Productive efficiency

In microeconomic theory, productive efficiency (or production efficiency) is a situation in which the economy or an economic system (e.g., bank, hospital, industry, country) operating within the constraints of current industrial technology cannot increase production of one good without sacrificing production of another good. In simple terms, the concept is illustrated on a production possibility frontier (PPF), where all points on the curve are points of productive efficiency. An equilibrium may be productively efficient without being allocatively efficient — i.e. it may result in a distribution of goods where social welfare is not maximized (bearing in mind that social welfare is a nebulous objective function subject to political controversy).
Productive efficiency is an aspect of economic efficiency that focuses on how to maximize output of a chosen product portfolio, without concern for whether your product portfolio is making goods in the right proportion; in misguided application, it will aid in manufacturing the wrong basket of outputs faster and cheaper than ever before.
Productive efficiency of an industry requires that all firms operate using best-practice technological and managerial processes and that there is no further reallocation that bring more output with the same inputs and the same production technology. By improving these processes, an economy or business can extend its production possibility frontier outward, so that efficient production yields more output than previously.
Productive inefficiency, with the economy operating below its production possibilities frontier, can occur because the productive inputs physical capital and labor are underutilized—that is, some capital or labor is left sitting idle—or because these inputs are allocated in inappropriate combinations to the different industries that use them.
In long-run equilibrium for perfectly competitive markets, productive efficiency occurs at the base of the average total cost curve — i.e. where marginal cost equals average total cost — for each good.
Due to the nature and culture of monopolistic companies, they may not be productively efficient because of X-inefficiency, whereby companies operating in a monopoly have less of an incentive to maximize output due to lack of competition. However, due to economies of scale it can be possible for the profit-maximizing level of output of monopolistic companies to occur with a lower price to the consumer than perfectly competitive companies.
Theoretical measures.
Many theoretical measures of production efficiency have been proposed in the literature as well as many approaches to estimate them.
The most popular measures of efficiency include Farrell measure (also known as Debreu–Farrell measure, since Debreu (1951) has similar ideas). This measure is also the reciprocal of the Shephard's distance function. These can be defined with either the input orientation (fix outputs and measure maximal possible reduction in inputs) or the output orientation (fix inputs and measure maximal possible expansion in outputs).
A generalisation of these is the so-called directional distance function, where one can select any direction (or orientation) for measuring the production efficiency.
The most popular for estimating production efficiency are data envelopment analysis and stochastic frontier analysis.
See the recent book by Sickles and Zelenyuk (2019) for comprehensive coverage of the theory and related estimation and many references therein.


Packaging machinery

Packaging machinery is used throughout all packaging operations, involving primary packages to distribution packs. This includes many packaging processes: fabrication, cleaning, filling, sealing, combining, labeling, overwrapping, palletizing.
Overview.
Some packaging operations cannot be accomplished without packaging equipment. For example many packages include heat seals to prepare or seal a package. Heat sealers are needed, even in slow labor-intensive operations.
With many industries, the effectiveness of the heat seal is critical to product safety so the heat sealing operation must closely controlled with documented Verification and validation protocols. Food, drug, and medical regulations require consistent seals on packages. Proper equipment is needed.
Automation.
Packaging operations can be designed for variable package sizes and forms or for handling only uniform packages, where the machinery or packaging line is adjustable between production runs. Certainly slow manual operations allow workers to be flexible to package variation but also some automated lines can handle significant random variation.
Moving from manual operations, through semi-automatic operations to fully automated packaging lines offers advantages to some packagers. Other than the obvious control of labor costs, quality can be more consistent, and throughput can be optimized.
Efforts at packaging line automation increasingly use programmable logic controllers and robotics.
Large fully automatic packaging lines can involve several pieces of major equipment from different manufactures as well as conveyors and ancillary equipment. Integrating such systems can be a challenge. Often consultants or external engineering firms are used to coordinate large projects.
Choosing packaging machinery.
Choosing packaging machinery includes an assessment of technical capabilities, labor requirements, worker safety, maintainability, serviceability, reliability, ability to integrate into the packaging line, capital cost, floorspace, flexibility (change-over, materials, multiple products, etc.), energy requirements, quality of outgoing packages, qualifications (for food, pharmaceuticals, etc.), throughput, efficiency, productivity, ergonomics, return on investment, etc.
Packaging machinery can be:
In addition to purchasing equipment, leasing options are often attractive.
Machinery must be compatible with the expected operating conditions. For example, cold temperature operations require special considerations. Some industries must perform periodic washdowns of all equipment. This high pressure chemical washing puts special demands on machinery and control systems. Condensation within closed portions of machinery can also be problematic.
Machinery needs to keep control of the product being packaged. For example, powders need to be stable, liquids cannot slosh out, etc.
Some manufacturers decide not to do their own packaging but to employ contract packagers to perform all or some operations. Capital, labor, and other costs are outsourced.
Types of machinery.
Packaging machines may be of the following general types:
Function.
Packaging is necessary to protect products, and is now done mainly through the use of packaging machinery. Machinery plays increasingly important roles such as:


Jig borer

The jig borer is a type of machine tool invented at the end of World War I to enable the quick and precise location of hole centers. It was invented independently in Switzerland and the United States. It resembles a specialized kind of milling machine that provides tool and die makers with a higher degree of positioning precision (repeatability) and accuracy than those provided by general machines. Although capable of light milling, a jig borer is more suited to highly accurate drilling, boring, and reaming, where the quill or headstock does not see the significant side loading that it would with mill work. The result is a machine designed more for location accuracy than heavy material removal.
A typical jig borer has a work table of around which can be moved using large handwheels (with micrometer-style readouts and verniers) on particularly carefully made shafts with a strong degree of gearing; this allows positions to be set on the two axes to an accuracy of . It is generally used to enlarge to a precise size smaller holes drilled with less accurate machinery in approximately the correct place (ie with the small hole strictly within the area to be bored out for the large hole).
Jig borers are limited to working materials that are still soft enough to be bored. Often a jig is hardened; for a jig borer this requires the material to be bored first and then hardened, which may introduce distortion. Consequently the jig grinder was developed as a machine with the precision of the jig borer, but capable of working materials in their hardened state.
History.
Before the jig borer was developed, hole center location had been accomplished either with layout (either quickly-but-imprecisely or painstakingly-and-precisely) or with drill jigs (themselves made with painstaking-and-precise layout). The jig borer was invented to expedite the making of drill jigs, but it helped to eliminate the need for drill jigs entirely by making quick precision directly available for the parts that the jigs would have been created for. The revolutionary underlying principle was that advances in machine tool control that expedited the making of jigs were fundamentally a way to expedite the cutting process itself, for which the jig was just a means to an end. Thus the jig borer's development helped advance machine tool technology toward later NC and CNC development. The jig borer was a logical extension of manual machine tool technology that began to incorporate some then-novel concepts that would become routine with NC and CNC control, such as:
Franklin D. Jones, in his textbook "Machine Shop Training Course" (5th ed), noted:
Several innovations in the development of the jig borer were the work of the Moore Special Tool Company. In particular, the adoption of hardened and accurate leadscrews, formed by grinding, rather than a soft leadscrew with a compensating nut.
The technological advances that led to the jig borer and NC were about to usher in the age of CNC and CAD/CAM, radically changing the way people manufacture many of their goods.


Diamond blade

A diamond blade is a saw blade which has diamonds fixed on its edge for cutting hard or abrasive materials. There are many types of diamond blade, and they have many uses, including cutting stone, concrete, asphalt, bricks, coal balls, glass, and ceramics in the construction industry; cutting semiconductor materials in the semiconductor industry; and cutting gemstones, including diamonds, in the gem industry.
Types.
Diamond blades are available in different shapes:
Diamond blades designed for specific uses include marble, granite, concrete, asphalt, masonry, and gem-cutting blades. General purpose blades are also available.
Manufacturing methods.
Electroplating.
Blades using diamonds embedded in a metal coating, typically of nickel electroplated onto a steel blade base, can be made to be very thin—blades can be tens of micrometres thick, for use in precise cuttings.
Vacuum brazing.
Vacuum brazed diamond saw blades are manufactured by brazing synthetic diamond particles to the outside edge of the circular saw blade in a vacuum brazing furnace. All of the diamond particles are fully exposed and fastened on the exterior cutting edge of the blade instead of being embedded within a metal-diamond mixture. Depending on the manufacturer's recommended blade application, vacuum brazed blades will cut a wide variety of material including concrete, masonry, steel, various irons, plastic, tile, wood and glass.
Finer synthetic diamond grits will reduce the chipping of tile and burring of steel and provide a smoother finish. Larger diamond grits will provide a higher cutting speed, but will be more likely to cause chipping, burring, or cracking. Fire departments sometimes use vacuum brazed saw blades and require blades to be made with a very large diamond grit, to tear through material quickly. An intermediate grit size is used by the production industry.
Sintering.
Sintered metal-bonded diamond blades are the most common type of blade. These blades consist of a steel core (the base is steel plate, unlike that of the wires used in diamond wire saws) and "diamond segments", which are made by combining synthetic diamond crystals with metal powder and then sintering them. The diamond segments are also known as the "cutting teeth" of the blade.
The steel core can vary in design. Some cores have spaces (known as gullets) between segments to provide cooling and slurry removal, while others have a single continuous rim for smoother cutting. The type of core that can be used depends on the type of materials that the diamond blade is designed to cut.
Generally, there are three types of sintered metal-bonded diamond blades according to their manufacturing methods: wholly sintered diamond blades, silver brazed diamond blades and laser welded diamond blades.
A wholly sintered diamond blade is made by putting the steel core, together with the diamonds and the metal bond materials, into a mold and then sintering it in a sintering furnace equipment. Consequently, the diameter of wholly sintered diamond blades is not very large, normally not more than . Because it is participating in the sintering process, the steel core cannot be quenched, so the hardness and strength of the core are not very high. This means that these types of diamond blade may deform in high-load and high-intensity cutting processes and can exhibit low cutting efficiency.
Silver brazed and laser welded diamond blades do not have this weakness because their diamond segments and steel core are treated separately. The steel core can be quenched and processed with other heat treatments, so its hardness and strength can be high, meaning that the blade can be used in high-load and high-intensity cutting processes with high cutting efficiency and a smaller degree of deformation.
Silver brazed diamond blades' diamond segments are brazed to the steel core using a silver solder. These blades can only be used in wet cuttings. If they are used in dry cuttings, the silver solder may melt and the segments can break from the steel core and become a serious safety hazard. A laser melts and combines the metal of the diamond segment and the steel core creating a stronger weld, which can hold the segments even in high temperatures, meaning that laser welded diamond blades can be used to cut many types of stone without water cooling. However, when cutting very hard or abrasive materials, e.g., concrete containing reinforcing rebar, laser welded diamond blades should also be used with adequate water. Otherwise, it is possible for the diamond segment itself to break or the steel core below the segment to wear and break, creating serious safety hazards.
Application of sintered metal-bonded diamond blades.
A diamond blade grinds, rather than cuts, through material. Blades typically have rectangular teeth (segments) which contain diamond crystals embedded throughout the segment for grinding through very hard materials.
The "bond" is a term used for the softness or hardness of the powder metal being used to form the segments. The powdered metals hold the diamonds in place. The bond controls the rate at which the diamond segments wear down allowing new diamonds to become exposed at the surface to continue grinding with a "sharp" edge. An important step in choosing a blade is to match the bond to the specific material to be cut. Additional factors to consider are the type and power of the equipment to be used and the availability of water. Harder materials need a softer bonded segment to allow for continuous diamond exposure. Softer materials like asphalt or freshly poured concrete can use a harder segment to resist the increased wear that softer, abrasive materials create. In addition, the diamonds' grit (size), toughness, and concentration should also match the nature of the material to be sawed. For example, when hard materials are cut, the diamonds should be smaller.
There are other factors that should be considered when choosing a diamond blade for a particular application. These include the type (manufacturing method) of the blade, the availability of water in the cutting process, the horsepower of the saw, and the acceptable level of noise created by the saw. For example, if the horsepower of a saw machine is large, the diamond concentration of the diamond blade should be higher, or the bond should be harder. Higher diamond concentration will decrease the impact on each single diamond in working, while a harder bond will hold the diamonds more firmly.
Cutting with or without water.
Many blades are designed to operate either wet or dry. However, diamond tools and blades work better when wet, and dry cutting should be limited to situations in which water cannot or should not be used. Water will prevent the blade from overheating, greatly reduce the amount of harmful dust created by cutting, remove the slurry from the cut, and extend the life of the blade, since diamond is unable to withstand the forces involved at the elevated temperatures involved in dry cutting ceramic and abrasive materials, and will be subject to rapid tool wear and possible failure.
When water cannot be used (in, for example, electrical saws), measures should be taken to ensure that the operator does not inhale the dust created by the process, which can cause silicosis, a serious lung disease. When dry cutting, the blade should be allowed to cool off periodically. Cooling can be increased by allowing the blade to spin freely out of the cut. The OSHA has strict regulations regarding silica dust and requires a N95 NIOSH-approved respirator in work sites where dangerous amounts of silica dust are present.
References.
Sources.


Heat-affected zone

In fusion welding, the heat-affected zone (HAZ) is the area of base material, either a metal or a thermoplastic, which is not melted but has had its microstructure and properties altered by welding or heat intensive cutting operations. The heat from the welding process and subsequent re-cooling causes this change from the weld interface to the termination of the sensitizing temperature in the base metal. The extent and magnitude of property change depends primarily on the base material, the weld filler metal, and the amount and concentration of heat input by the welding process.
The thermal diffusivity of the base material plays a large role—if the diffusivity is high, the material cooling rate is high and the HAZ is relatively small. Alternatively, a low diffusivity leads to slower cooling and a larger HAZ. The amount of heat input during the welding process also plays an important role as well, as processes like oxyfuel welding use high heat input and increase the size of the HAZ. Processes like laser beam welding and electron beam welding give a highly concentrated, limited amount of heat, resulting in a small HAZ. Arc welding falls between these two extremes, with the individual processes varying somewhat in heat input. To calculate the heat input for arc welding procedures, the following formula is used:
where = heat input (kJ/mm), = voltage (V), = current (A), and = welding speed (mm/min). The efficiency is dependent on the welding process used, with gas tungsten arc welding having a value of 0.6, shielded metal arc welding and gas metal arc welding having a value of 0.8, and submerged arc welding 1.0.


Power Surfacing

Power Surfacing is a computer-aided design software that allows users to create and edit complex freeform surfaces in SOLIDWORKS. It is developed by nPower Software, a division of IntegrityWare Inc., and is available as an add-in for SOLIDWORKS.
Overview.
Power Surfacing uses subdivision surface (Sub-D) modeling and Non-uniform rational B-spline (NURBS) modeling methods together, to provide a flexible and intuitive way of designing organic shapes with high quality class A surfaces. Users can create and manipulate Sub-D models inside SOLIDWORKS, and convert them to NURBS models that are compatible with SOLIDWORKS features and commands. Power Surfacing also supports reverse engineering of scanned meshes with Power Surfacing RE, a separate add-in that can reconstruct Sub-D models from polygonal meshes.
Power Surfacing is designed for industrial design, product design, automotive design, jewelry design, and other applications that require complex freeform surfaces. It aims to simplify the design process and reduce the editing time for organic shapes, compared to traditional surface creation methods. It also provides video tutorials and examples to help users learn how to use the software effectively.
Features.
Some of the features of Power Surfacing include:
Usage.
Power Surfacing functions as a generative design tool, generating iterative, evolutionary results based on initial constraints.
This tool is commonly used to optimize manufacturing processes for parts in various industries, such as automotive, packaging design, and medical implants.
Power Surfacing can also reverse-engineer the shapes of 3D-scanned objects and recreate their geometry algorithmically, facilitating reproduction through industrial production processes. This capability can be employed to digitally replicate physical aspects of human anatomy, such as bones, and modify the model to produce precise-fitting physical Prosthesis for patients.


Gas immersion laser doping

Gas immersion laser doping (GILD) is a method of doping a semiconductor material such as silicon.
In the case of doping silicon with boron to create a P-type semiconductor material, a thin wafer of silicon is placed in a containment chamber and is immersed in boron gas. A pulsed laser is directed at the silicon wafer and this results in localised melting and subsequent recrystallisation of the silicon wafer material, allowing boron atoms in the gas to diffuse into the molten sections of the silicon wafer. The result of this process is a silicon wafer with boron impurities, creating a P-type semiconductor.


Haas Automation

Haas Automation, Inc is an American machine tool builder headquartered in Oxnard, California. The company designs and manufactures lower cost machine tools and specialized accessory tooling, mostly computer numerically controlled (CNC) equipment, such as vertical machining centers and horizontal machining centers, lathes/turning centers, and rotary tables and indexers. Most of its products are manufactured at the company's main facility in Oxnard. The company is also involved in motorsports: it owns the Haas F1 Team and is a co-owner of Stewart-Haas Racing in NASCAR.
Haas is one of the largest machine tool builders in the world by total unit volume.
History.
Gene Haas founded Haas Automation in 1983 to manufacture machine tool accessory tooling. The company entered the machine tool industry with the first fully automatic, programmable collet indexer. Over the next four years, the company expanded its product line to include fully programmable rotary tables, rotary indexers, and other machine tool accessories.
In 1987, Haas Automation began developing its first vertical machining center (VMC), the VF-1, a machine designed to perform operations such as milling, drilling, tapping, and boring. The first VF-1 prototypes were completed in 1988, and introduced at the International Manufacturing Technology Show (IMTS '88) in Chicago, Illinois.
Products.
The company manufactures several lines of CNC machine tools for the metalworking industry.
Vertical Mills.
VF Series.
VF series mills are a range of 3-axis vertical machining centers, which can be outfitted with 4th and 5th axis drives if so configured. These mills are available in different sizes, ranging from VF-1 to VF-14.
The VF in the name stands for "Very First" as the first machine Haas produced was the VF-1 ("Very First One"). One of these machines was restored by an employee, gifted to Gene Haas, and now resides in Haas's demo room in Oxnard, CA.
Universal Machines (UMC).
Haas universal machining centers (known as UMC) are 5-axis bridge-type vertical machines. They were first introduced in 2015.
Mini Mill.
The mini mill was introduced as a small footprint alternative to the VF series mills, featuring a smaller casting while still maintaining a 40 taper spindle.
Toolroom Mills (TM).
The TM series was first introduced as essentially a "CNC-capable toolroom mill”. Originally, these mills did not feature an enclosure, but have since been outfitted with an enclosure that encompasses the bottom and sides of the machine. These machines are characterized by a smaller casting and slower rapids, as they are targeted towards customers who do not require production capabilities.
Drill/Tap/Mill Series (DT / DM).
The Haas DT series was originally introduced as a 30 taper high-speed machine, ideal for operations where high speed and small footprint are required, but the ability to handle large axial cutting loads is not needed. Eventually, the DM series was introduced as a 40 taper variant of the DT machine, but does not offer the 20,000 RPM spindle option.
Compact Mill.
The CM is focused on machining small parts where high accuracy is required. The CM is a 20 taper machine, with spindles from 30,000 to 50,000 RPM. Haas only offers one machine in this series, the CM-1.
Gantry Series (GM / GR).
Gantry Series mills feature a static bed, a bridge that moves along the Y axis, and a head that moves along the X axis. The two primary use cases for GM series machines are large molds. GM series machines feature a more substantial casting with improved chip management as opposed to the GR series. The GM-2-5AX is also available, which is simply a GM-2 featuring two extra axes affixed to the head.
Certifications.
Haas Automation is an ISO 9001 certified company. All machine tools carry the ETL Listed mark, certifying that they conform to the NFPA 79 electrical standard for industrial machinery and the Canadian equivalent, CAN/CSA C22.2 No. 73. The company is also entitled to affix the CE mark to its products.
Sales.
Products are distributed worldwide through a network of independently owned franchised local "factory outlet" businesses that provide sales, service, and applications support for Haas machine tools. Introduced in 1999, with the first outlet established in Torrance, California, it was applied to the company's existing worldwide network, and then expanded to Europe.


Dynamic Materials Corporation

DMC Global Inc.  is a metalworking business headquartered in Broomfield, Colorado. It was formed in 1971, then known as Explosive Fabricators Inc.
The company operates in two segments, explosive metalworking and perforation (oil well). The explosive metalworking segment utilizes explosives to perform metal cladding and shock synthesis. Its principal product is an explosion welded clad metal plate, which is used in the construction of heavy, corrosion-resistant pressure vessels, and heat exchangers for petrochemical, refining, and hydrometallurgy industries.


Responsive computer-aided design

Responsive computer-aided design (also simplified to responsive design) is an approach to computer-aided design (CAD) that utilizes real-world sensors and data to modify a three-dimensional (3D) computer model. The concept is related to cyber-physical systems through blurring of the virtual and physical worlds, however, applies specifically to the initial digital design of an object prior to production.
The process begins with a designer creating a basic design of an object using CAD software with parametric or algorithmic relationships. These relationships are then linked to physical sensors, allowing them to drive changes to the CAD model within the established parameters. Reasons to allow sensors to modify a CAD model include customizing a design to fit a user's anthropometry, assisting people without CAD skills to personalize a design, or automating part of an iterative design process in similar fashion to generative design. Once the sensors have affected the design it may then be manufactured as a one-off piece using a digital fabrication technology, or go through further development by a designer.
Context.
Responsive computer-aided design is enabled by ubiquitous computing and the Internet of Things, concepts which describe the capacity for everyday objects to contain computing and sensing technologies. It is also enabled by the ability to directly manufacture one-off objects from digital data, using technologies such as 3D printing and computer numerical control (CNC) machines. Such digital fabrication technologies allow for customization, and are drivers of the mass-customization phenomenon. They also provide new opportunities for consumers to participate in the design process, known as co-design.
As these concepts mature, responsive design is emerging as an opportunity to reduce reliance on graphical user interfaces (GUIs) as the only method for designers and consumers to design products, aligning with claims by Golden Krishna that "the best design reduces work. The best computer is unseen. The best interaction is natural. The best interface is no interface." Calls to reduce reliance on GUIs and automate some of the design process connects with Mark Weiser's original vision of ubiquitous computing.
Related concepts.
A variety of similar research areas are based on gesture recognition, with many projects using motion capture to track the physical motions of a designer and translate them into three-dimensional geometry suitable for digital fabrication. While these share similarities to responsive design through their cyber-physical systems, they require direct intent to design an object and some level of skill. These are not considered responsive, as responsive design occurs autonomously and may even occur without the user being aware that they are designing at all.
This topic has some common traits with responsive web design and responsive architecture, with both fields focused on systems design and adaptation based on functional conditions.
Current work.
Responsive computer-aided design has been used to customize fashion, and is currently an active area of research in footwear by large companies like New Balance who are looking to customize shoe midsoles using foot pressure data from customers.
Sound waves have also been popular to customize 3D models and produce sculptural forms of a baby's first cries, or a favorite song.


Implant induction welding of thermoplastics

Implant induction welding is a joining method used in plastic manufacturing. The welding process uses an induction coil to excite and heat electromagnetically susceptible material at the joint interface and melt the thermoplastic. The susceptible material can be contained in a gasket placed between the welding surface, or within the actual components of a composite material. Its usage is common for large, unusually shaped, or delicate parts that would be difficult to weld through other methods.
Physical Mechanisms.
In non-magnetic electrical conductors like aluminum, nickel, or copper, an alternating electromagnetic field will induce Eddy currents in the material. These currents generate thermal energy through Joule heating. Ferromagnetic materials like iron and carbon steels will see heating from both Eddy current formation and Hysteresis losses.
Welding Process.
Material Considerations.
Induction heating is an efficient method of heating electrically conductive or magnetic materials. Warm-up times are minimal and direct contact with the part is not needed. Unfortunately most thermoplastics are non-magnetic and excellent insulators. To take advantage of induction heating for thermoplastic welding purposes, a susceptible implant must be used as an intermediary material. Nearly any electrical conductor or ferromagnetic material may be used as an implant. Implant styles include meshes, fibers, and fine powders. The most common gasket design is a thermoplastic composite with suspended susceptible fibers. . This composite gasket can be formed into any shape required for the welding application. The gasket matrix is typically made of the same thermoplastic being welded. In situations where two dissimilar materials are to be welded, the gasket material is usually a blend of the two thermoplastics.
Composite Materials.
Carbon fiber is of interest due to its widespread use in composite materials. Provided there are closed loops of carbon within the composite structure, eddy currents can be induced in the material. Unidirectional carbon fiber composites can have poor susceptibility when fiber to fiber contact is limited.
Focusing heat only at the weld point is difficult with susceptible composite fibers throughout the material. In carbon fiber composites, thin electrically insulating layers with non-aligned fibers may be inserted between conducting layers to electrically isolate the joint surface from the material bulk. Using this technique, induction heating of the bulk is avoided.
Equipment.
An induction generator is used to produce high frequency current in the range of 2-10 Mhz. The range used is regulated by the FCC to avoid interference with broadcast signals.
An induction coil converts the high frequency current from the induction generator into the necessary alternating magnetic field. A single turn coil may be used when space is limited, however multiturn coil designs are more common due to their generation of a stronger and deeper penetrating magnetic field. Split coil designs are also available, which may be dissasembeled to fully surround a large part such as plastic piping. The high currents used in induction welding produce large amounts of heat in the coil. To avoid overheating, the coil turns are made with hollow tubing, and water is circulated during welding. Coil heat is dissipated by an attached heat exchanger.
Fixtures are used to hold the parts in position during welding. One fixture is fixed and the other moveable so that a press may apply and maintain pressure during heating and cooling.
Welding Steps.
An implant rich gasket is placed at the surface to be welded. Pressure is applied to the joint to force out air cavities and ensure a sound bond. An electromagnetic field is applied by the induction coil to heat the implants, and pressure is applied to the joint. Heat conducts into the surrounding thermoplastic, which melts the gasket and creates a melt layer at the joint surfaces. The applied pressure flows the molten thermoplastic and fills the joint. When sufficient bonding has been achieved, the induction coil is turned off and the joint is cooled under pressure. For large items with long joints, the joint can be welded continuously by scanning the active coil along the length of the interface.
Parameters.
Power.
Typical induction generators provide a power output of 1-5 kWs. High power output is necessary for longer and larger joints. Power output must also be increased as coil distance from the joint increases, due to electromagnetic field decay.
Pressure.
Even distribution of the molten polymer in the joint is imperative for strong bonding. Weld pressure must be sufficient to induce squeeze flow in the molten gasket, achieve intimate contact with the joint surface, and fill the joint.
Weld Time and Cooling Time.
Weld time will vary based on the joint size, the volume of susceptible implant material, and the power and frequency. Cycle times can be very fast since no preheating is needed, and heat generation happens exclusively at the weld joint. This also benefits the cooling time. With little heat wasted on the bulk of the part, cooling is brief. Under 1 second for some applications.
Joint Design.
Unusual joint designs are possible using implant induction welding. The simplest is the flat to flat joint, where a gasket is placed between two thermoplastic plates. This joint is common for continuous welding processes, or long weld lines where the active coil is scanned along the joint interface. The flat to groove joint uses a plate with a channel to accurately align the weld versus the flat to flat joint. The tongue in groove joint is similar to the flat to groove joint, but has the advantage of complete encapsulation of the gasket and a pressure tight seal.
Applications.
Food Packaging.
Implant induction welding is heavily used in the production of Tetra Pak containers for products like juice boxes. The use of induction heating shortens the sealing time versus other joining methods that use external heat, and avoids damage to the paperboard layer from direct contact with hot tooling. An aluminum foil layer is used to block oxygen diffusion into the packaging, so no additional implant material is needed.
Automotive Manufacturing.
The automotive industry makes large scale use of implant induction welding for the manufacture of large plastic items such as bumpers, plastic body panels, and fuel tanks. Manufacturing costs of components with complex geometries are brought down by manufacturing the parts in separate pieces, to be assembled later using induction welding.
Tamper Proof Packaging.
Polyethylene coated aluminum foil is induction welded to the top of many food, supplement, and drug containers. The seal helps retain product quality and provides evidence of tampering.


Industrial digital printer

Industrial Digital Printers can be divided into a variety of different categories. As the industry becomes more mature, and the number of manufacturers increases, the line between the broad descriptions becomes less defined.
Digital Printers are sometimes erroneously referred to as being “Digital Printing Presses”. The term Printing Press refers to the nature of the process, in which there is contact between the system that applies the ink to the substrate and substrate that the ink is pressed onto. Digital Printers however are non-impact printing processes; to print, a devices “fires” drops of ink from the print heads onto the substrate.
Categories.
Here is a broad outline of classes of digital printers in the graphic arts segment of the printing industry.
High volume.
These systems print at speeds measured at between 200 and 400 square metres per hour.
Super wide format.
These printers are generally roll-to-roll and have a print bed that is 2m to 5m wide. Mostly used for printing billboards and generally have the capability of printing between 60 and 160 square metres per hour. Traditionally these were manufactured by Western manufacturers, however in the last 5 to 10 years Korean, Japanese and Chinese printer manufacturers have been aggressively competing in this category with more reliable faster printers. Margins dictate that many well-known European brands are currently manufactured in the East and simply rebranded in Europe and the United States for distribution around the world. Market antipathy to products manufactured in the East is becoming obsolescent as the vast majority of products used commercially are either assembled complete in the East or have their parts manufactured and exported from there. The low manufacturing costs of parts and machines in the East would make it extremely difficult for super-wide format digital printer suppliers around the world to compete profitably unless they turned to countries like China, Korea and Japan for their manufacturing.
Wide format.
These printers are most commonly manufactured in Korea and China with India starting to develop printers as well. These machines are now available from 0.9 metres to 3 metres wide. Generally they are capable of printing from 10 to 60 square metres per hour.
High resolution.
Printers are generally referred to as "Super-Wide format" when their print bed exceeds 2.2m in width. For many applications at this size resolution becomes secondary to print speed - which is why many machines over 3m wide are designed for speed over resolution. In the 1980s billboards were generally printed at resolutions as low as 80dpi (dots per inch). Resolutions today are much higher because of the improvements in technology but printing billboards, vehicle graphics, building wraps and the like do not require the ultra-high resolutions of 1440dpi and upwards often associated with standard wide format printers. It is normal for super-wide format digital printers to function at maximum resolutions of between 540dpi and around 1040dpi. However even these resolutions are rarely used in a production environment, billboards and building wraps for example are often done at between 200dpi and 350dpi and the result relies on the viewing distance for the impactful, colourful graphics the public sees on roadsides and buildings. The fact that they are capable of printing at these higher resolutions is still important though because it attests to the size of the ink droplet being laid down by the inkjet solvent and eco-solvent machines. These ink droplets are measured in pica-litres and a print done at 200dpi will look more defined if it is printed with smaller ink droplets when compared to a machine laying down bigger ink droplets. The primary print head technologies used in ultra-wide format digital outdoor printing comes down to a few print head manufacturers worldwide including (but not restricted to) Piezo, Seiko and Spectra as the primary competitors and their print heads are used in most machines from a variety of manufacturers. They have their pros and cons and Piezo appears to focus more on the higher resolution side of the industry whereas Seiko and Spectra-Polaris tend more towards the robust, high production capabilities required in a manufacturing environment.
Print heads.
At this time these printers use printers using PZT crystals as micro-pumps to eject the droplets from the nozzles. The crystals deform to generate a “shock wave” in the fluid inks which in turn ejects a drop from the nozzle. A combination of surface tension, capillary pressure and other complex fluid dynamics ensures that the fluid is refilled ready for the next fire cycle.


Non functional pad

A non-functional pad is a pad in a printed circuit board that is not connected to a track on the layer it is on.
Removal.
Non-functional pads can be removed at any phase of the design process. Some software allows precise control during the design process, and also removes the non-functional pads during output file creation. Furthermore, some board manufacturers remove non-functional pads during data preparations.
Occasionally, this process of non-functional pad removal is also called unused pad suppression.
The benefits of removing the non-functional pads are limited. Electrically, it creates needless extra capacitance in certain designs, which needs to be removed. Removing non-functional pads can improve the drilling process, as it lessens drill wear.
Non-functional pad removal can influence the reliability. (e.g. barrel cracking failure mode). Removal can increase or decrease reliability. Depending on design parameters, removing the non-functional pads can free up routing space.
Non-functional pads naturally also affect thermal characteristics.
Sometimes, non-functional pads (or their removal) are used for copper balancing, which affects etching, bow and twist and other effects.


Deep reactive-ion etching

Deep reactive-ion etching (DRIE) is a highly anisotropic etch process used to create deep penetration, steep-sided holes and trenches in wafers/substrates, typically with high aspect ratios. It was developed for microelectromechanical systems (MEMS), which require these features, but is also used to excavate trenches for high-density capacitors for DRAM and more recently for creating through silicon vias (TSVs) in advanced 3D wafer level packaging technology. In DRIE, the substrate is placed inside a reactor, and several gases are introduced. A plasma is struck in the gas mixture which breaks the gas molecules into ions. The ions accelerated towards, and react with the surface of the material being etched, forming another gaseous element. This is known as the chemical part of the reactive ion etching. There is also a physical part, if ions have enough energy, they can knock atoms out of the material to be etched without chemical reaction.
DRIE is a special subclass of RIE.
There are two main technologies for high-rate DRIE: cryogenic and Bosch, although the Bosch process is the only recognised production technique. Both Bosch and cryo processes can fabricate 90° (truly vertical) walls, but often the walls are slightly tapered, e.g. 88° ("reentrant") or 92° ("retrograde").
Another mechanism is sidewall passivation: SiOxFy functional groups (which originate from sulphur hexafluoride and oxygen etch gases) condense on the sidewalls, and protect them from lateral etching. As a combination of these processes deep vertical structures can be made.
Cryogenic process.
In cryogenic-DRIE, the wafer is chilled to −110 °C (163 K). The low temperature slows down the chemical reaction that produces isotropic etching. However, ions continue to bombard upward-facing surfaces and etch them away. This process produces trenches with highly vertical sidewalls. The primary issues with cryo-DRIE is that the standard masks on substrates crack under the extreme cold, plus etch by-products have a tendency of depositing on the nearest cold surface, i.e. the substrate or electrode.
Bosch process.
The Bosch process, named after the German company Robert Bosch GmbH which patented the process, also known as pulsed or time-multiplexed etching, alternates repeatedly between two modes to achieve nearly vertical structures:
Each phase lasts for several seconds. The passivation layer protects the entire substrate from further chemical attack and prevents further etching. However, during the etching phase, the directional ions that bombard the substrate attack the passivation layer at the bottom of the trench (but not along the sides). They collide with it and sputter it off, exposing the substrate to the chemical etchant.
These etch/deposit steps are repeated many times over resulting in a large number of very small isotropic etch steps taking place only at the bottom of the etched pits. To etch through a 0.5 mm silicon wafer, for example, 100–1000 etch/deposit steps are needed. The two-phase process causes the sidewalls to undulate with an amplitude of about 100–500 nm. The cycle time can be adjusted: short cycles yield smoother walls, and long cycles yield a higher etch rate.
Applications.
RIE "deepness" depends on application:
What distinguishes DRIE from RIE is etch depth: Practical etch depths for RIE (as used in IC manufacturing) would be limited to around 10 µm at a rate up to 1 µm/min, while DRIE can etch features much greater, up to 600 µm or more with rates up to 20 µm/min or more in some applications.
DRIE of glass requires high plasma power, which makes it difficult to find suitable mask materials for truly deep etching. Polysilicon and nickel are used for 10–50 µm etched depths. In DRIE of polymers, Bosch process with alternating steps of SF6 etching and C4F8 passivation take place. Metal masks can be used, however they are expensive to use since several additional photo and deposition steps are always required. Metal masks are not necessary however on various substrates (Si [up to 800 µm], InP [up to 40 µm] or glass [up to 12 µm]) if using chemically amplified negative resists.
Gallium ion implantion can be used as etch mask in cryo-DRIE. Combined nanofabrication process of focused ion beam and cryo-DRIE was first reported by N Chekurov "et al" in their article "The fabrication of silicon nanostructures by local gallium implantation and cryogenic deep reactive ion etching".
Precision Machinery.
DRIE has enabled the use of silicon mechanical components in high-end wristwatches. According to an engineer at Cartier, “There is no limit to geometric shapes with DRIE,”. With DRIE it is possible to obtain an aspect ratio of 30 or more, meaning that a surface can be etched with a vertical-walled trench 30 times deeper than its width.
This has allowed for silicon components to be substituted for some parts which are usually made of steel, such as the hairspring. Silicon is lighter and harder than steel, which carries benefits but makes the manufacturing process more challenging.


Push–pull strategy

The business terms push and pull originated in logistics and supply chain management, but are also widely used in marketing and in the hotel distribution business.
Walmart is an example of a company that uses the push vs. pull strategy.
Supply-chain management.
Complete definition.
There are several definitions on the distinction between push and pull strategies. Liberopoulos (2013) identifies three such definitions:
Other definitions are:
Information flow.
With a push-based supply chain, products are pushed through the channel, from the production side up to the retailer. The manufacturer sets production at a level in accord with historical ordering patterns from retailers. It takes longer for a push-based supply chain to respond to changes in demand, which can result in overstocking or bottlenecks and delays (the bullwhip effect), unacceptable service levels and product obsolescence.
In a pull-based supply chain, procurement, production and distribution are demand-driven rather than to forecast. However, a pull strategy does not always require make to order production. Toyota Motors Manufacturing is frequently used as an example of pull production, yet do not typically produce to order. They follow the "supermarket model" where limited inventory is kept on hand and is replenished as it is consumed. In Toyota's case, Kanban cards are used to signal the need to replenish inventory.
A supply chain is almost always a combination of both push and pull, where the interface between the push-based stages and the pull-based stages is sometimes known as the "push–pull boundary". However, because of the subtle difference between pull production and make-to-order production, a more accurate name for this may be the "customer order decoupling point". An example of this is Dell's build to order supply chain. Inventory levels of individual components are determined by forecasting general demand, but final assembly is in response to a specific customer request. The decoupling point would then be at the beginning of the assembly line.
In a marketing "pull" system, the consumer requests the product and "pulls" it through the delivery channel. An example of this is the car manufacturing company Ford Australia. Ford Australia only produces cars when they have been ordered by customers.
Use of pull, push, and hybrid push-pull strategy.
Harrison summarized when to use each one of the three supply chain strategies:
Examples in "push" and "pull".
Hopp and Spearman consider some of the most common systems found in industry and the literature and classify them as either push or pull
Liberopoulos (2013) also classifies common systems according to different definitions on the distinction between push and pull.
Marketing.
An advertising push strategy refers to a situation when a vendor advertises its product to gain audience awareness, while the pull strategy implies the aims to reach audiences which have shown existing interest in the product or information about it. The difference between "push" and "pull" marketing can also be identified by the manner in which the company approaches the lead. If, for example, the company were to send a sales brochure, that would be considered pushing the opportunity toward the lead. If, instead, the company provided a subject matter expert as a speaker for an industry event attended by targeted leads, that could be one tactic used as part of a strategy to pull in a lead by encouraging that lead to seek out the expert in a moment of need for that expertise.
Hotel distribution.
The online world has brought this pull push decision to the hotel distribution business


The United Nations Humanitarian Response Depot (UNHRD) is an international network of six humanitarian support hubs located strategically around the world, that provide supply chain solutions to the international humanitarian community. The hubs are located in Brindisi (Italy), Dubai (UAE), Accra (Ghana), Panama City (Panama), Kuala Lumpur (Malaysia) and Las Palmas (Spain).
It is managed by the World Food Programme and currently serves 86 partners, such as UN organizations, government agencies and NGOs. It enables these partners to assist people affected by natural disasters or other complex emergencies by prepositioning vital relief items and allowing them to be dispatched rapidly to critical areas. In addition, the UNHRD network offers services and knowledge that allow various humanitarian partners to fulfill their missions rapidly and effectively.
Background.
Today's UNHRD Network dates back to an initiative by the Italian government in the mid-1980s: to pre-position relief items and support equipment for humanitarian operations at its military airport facilities. Expanding on the success of this method and envisioning a global network, WFP transformed the humanitarian depot into a logistic hub for emergency preparedness and response. In line with the United Nations Reforms for better coordinated development system and more effective humanitarian structures, UNHRD enhances the efficiency and effectiveness of humanitarian assistance, with the specific mandate to "assist the population living in countries affected by natural disasters or complex emergencies, through a prepositioning of relief and survival items and their rapid demobilization to the affected countries."
History.
The original UNHRD depot was inaugurated in Brindisi in the year 2000 to replace the United Nations Supply Depot (UNSD) in Pisa, then managed by the Office of Coordination of Humanitarian Affairs (OCHA). Upon decision of the Inter-Agency Standing Committee (IASC) the mandate to provide rapid and accessible stockpiling and demobilisation services to partners inside and outside the United Nations was transferred from OCHA to WFP. Subsequently, the hub was moved to the military airport at Brindisi in an effort to set up a new and robust logistics platform, available to all partners as a "shared resource".
In 2006, based on its own requirements and that of its partners, WFP replicated the successful Brindisi model by setting up further emergency response facilities in strategic locations worldwide, creating a network of HRDs in Africa, the Middle East, South East Asia and Latin America. Each of these locations has been selected to provide easy access to an airport, port and road systems, making access to a wide range of transportation methods available and allowing for consistently low response times of 24-48 hours.
Functions.
When Governments, UN agencies and NGOs look to respond quickly and efficiently to a disaster, they call on emergency supplies that are immediately available in UNHRD warehouses. By prepositioning relief items, the humanitarian community can support affected people at the very beginning of an emergency, often saving lives within the first 24–48 hours.
UNHRD offers a range of supply chain solutions to relief organizations around the globe, acting as a 'one-stop shop' to its partners for storage, procurement, transport, handling, stock borrowing, technical field assistance and training centre facilities.
Figures.
Originally, five humanitarian organisations relied on the UNHRD Network, including WFP itself. This number has since grown to 86 in 2017. Partner organisations that join the network are diverse, spanning UN agencies, governmental and non-governmental organisations.
In 2017, the UNHRD Network managed 575 shipments in 95 countries supporting 36 partners in responding to humanitarian emergencies, including Hurricane Irma, the Rohingya Refugees Crisis in Bangladesh, and the South Sudanese Refugee Crisis in Uganda.


Scheduling (production processes)

Scheduling is the process of arranging, controlling and optimizing work and workloads in a production process or manufacturing process. Scheduling is used to allocate plant and machinery resources, plan human resources, plan production processes and purchase materials.
It is an important tool for manufacturing and engineering, where it can have a major impact on the productivity of a process. In manufacturing, the purpose of scheduling is to keep due dates of customers and then minimize the production time and costs, by telling a production facility when to make, with which staff, and on which equipment. Production scheduling aims to maximize the efficiency of the operation, utilize maximum resources available and reduce costs.
In some situations, scheduling can involve random attributes, such as random processing times, random due dates, random weights, and stochastic machine breakdowns. In this case, the scheduling problems are referred to as "stochastic scheduling".
Overview.
Scheduling is the process of arranging, controlling and optimizing work and workloads in a production process. Companies use backward and forward scheduling to allocate plant and machinery resources, plan human resources, plan production processes and purchase materials.
The benefits of production scheduling include:
Production scheduling tools greatly outperform older manual scheduling methods. These provide the production scheduler with powerful graphical interfaces which can be used to visually optimize real-time work loads in various stages of production, and pattern recognition allows the software to automatically create scheduling opportunities which might not be apparent without this view into the data. For example, an airline might wish to minimize the number of airport gates required for its aircraft, in order to reduce costs, and scheduling software can allow the planners to see how this can be done, by analysing time tables, aircraft usage, or the flow of passengers.
Key concepts in scheduling.
A key character of scheduling is the productivity, the relation between quantity of inputs and quantity of output. Key concepts here are:
Scheduling algorithms.
Production scheduling can take a significant amount of computing power if there are a large number of tasks. Therefore, a range of short-cut algorithms (heuristics) (a.k.a. dispatching rules) are used:
Batch production scheduling.
Background.
Batch production scheduling is the practice of planning and scheduling of batch manufacturing processes. See Batch production. Although scheduling may apply to traditionally continuous processes such as refining, it is especially important for batch processes such as those for pharmaceutical active ingredients, biotechnology processes and many specialty chemical processes. Batch production scheduling shares some concepts and techniques with finite capacity scheduling which has been applied to many manufacturing problems. The specific issues of scheduling batch manufacturing processes have generated considerable industrial and academic interest.
Scheduling in the batch processing environment.
A batch process can be described in terms of a recipe which comprises a bill of materials and operating instructions which describe how to make the product. The ISA S88 batch process control standard provides a framework for describing a batch process recipe. The standard provides a procedural hierarchy for a recipe. A recipe may be organized into a series of unit-procedures or major steps. Unit-procedures are organized into operations, and operations may be further organized into phases.
The following text-book recipe illustrates the organization.
A simplified S88-style procedural organization of the recipe might appear as follows:
Note that the organization here is intended to capture the entire process for scheduling. A recipe for process-control purposes may have a more narrow scope.
Most of the constraints and restrictions described by Pinedo are applicable in batch processing. The various operations in a recipe are subject to timing or precedence constraints that describe when they start and or end with respect to each other. Furthermore, because materials may be perishable or unstable, waiting between successive operations may be limited or impossible. Operation durations may be fixed or they may depend on the durations of other operations.
In addition to process equipment, batch process activities may require labor, materials, utilities and extra equipment.
Cycle-time analysis.
In some simple cases, an analysis of the recipe can reveal the maximum production rate and the rate limiting unit. In the process example above if a number of batches or lots of Product C are to be produced, it is useful to calculate the minimum time between consecutive batch starts (cycle-time). If a batch is allowed to start before the end of the prior batch the minimum cycle-time is given by the following relationship:
formula_1
Where CTmin is the shortest possible cycle time for a process with M unit-procedures and τj is the total duration for the jth unit-procedure. The unit-procedure with the maximum duration is sometimes referred to as the bottleneck. This relationship applies when each unit-procedure has a single dedicated equipment unit.
If redundant equipment units are available for at least one unit-procedure, the minimum cycle-time becomes:
formula_2
Where is the number of redundant equipment for unit procedure .
If equipment is reused within a process, the minimum cycle-time becomes more dependent on particular process details. For example, if the drying procedure in the current example is replaced with another reaction in the reactor, the minimum cycle time depends on the operating policy and on the relative durations of other procedures. In the cases below, an increase in the hold time in the tote can decrease the average minimum cycle time.
Visualization.
Various charts are used to help schedulers visually manage schedules and constraints. The Gantt chart is a display that shows activities on a horizontal bar graph in which the bars represent the time of the activity. Below is an example of a Gantt chart for the process in the example described above.
Another time chart which is also sometimes called a Gantt chart shows the time during which key resources, e.g. equipment, are occupied. The previous figures show this occupancy-style Gantt chart.
Resources that are consumed on a rate basis, e.g. electrical power, steam or labor, are generally displayed as consumption rate vs time plots.
Algorithmic methods.
When scheduling situations become more complicated, for example when two or more processes share resources, it may be difficult to find the best schedule. A number of common scheduling problems, including variations on the example described above, fall into a class of problems that become very difficult to solve as their size (number of procedures and operations) grows.
A wide variety of algorithms and approaches have been applied to batch process scheduling. Early methods, which were implemented in some MRP systems assumed infinite capacity and depended only on the batch time. Such methods did not account for any resources, and would produce infeasible schedules.
Mathematical programming methods involve formulating the scheduling problem as an optimization problem where some objective, e.g. total duration, must be minimized (or maximized) subject to a series of constraints which are generally stated as a set of inequalities and equalities. The objective and constraints may involve zero-or-one (integer) variables as well as nonlinear relationships. An appropriate solver is applied for the resulting mixed-integer linear or nonlinear programming (MILP/MINLP) problem. The approach is theoretically guaranteed to find an optimal solution if one exists. The disadvantage is that the solver algorithm may take an unreasonable amount of time. Practitioners may use problem-specific simplifications in the formulation to get faster solutions without eliminating critical components of the scheduling model.
Constraint programming is a similar approach except that the problem is formulated only as a set of constraints and the goal is to arrive at a feasible solution rapidly. Multiple solutions are possible with this method.
Agent-based modeling describes the batch process and constructs a feasible schedule under various constraints. By combining with mixed-integer programming or simulated-based optimization methods, this approach could achieve a good balance between the solution efficiency and the schedule performance. A new development and framework addresses how to exploit the aggregation of several digital twins, representing different physical assets and their autonomous decision-making, together with a global digital twin, in order to perform production scheduling optimization.


List of fuel cell manufacturers

A fuel cell is an electrochemical energy conversion device. Fuel cells differ from batteries in that they are designed for continuous replenishment of the reactants consumed.
This is a partial list of companies currently producing commercially available fuel cell systems for use in residential, commercial, or industrial settings. Fuel cell systems from these manufacturers are currently being used to generate AC or DC electricity, heat, water, or any combination of the three.


High-area rapid printing

High-area rapid printing (HARP) is a stereolithography (SLA) method that permits the continuous, high-throughput printing of large objects at rapid speeds (Figure 1). This method was introduced in 2019 by the Mirkin Research Group at Northwestern University in order to address drawbacks associated with traditional SLA manufacturing processes. Since the polymerization reactions involved in SLA are highly exothermic processes, the production of objects at high-throughputs is associated with high temperatures that can result in structural defects. HARP addresses this problem by utilizing a solid-liquid slip boundary (Figure 2) that cools the resin by withdrawing heat from the system. This allows for large structures to be fabricated quickly without the temperature-associated defects inherent to other SLA processes.
Design and Advantages.
Additive manufacturing, or 3D printing, has allowed for the rapid prototyping of intricate structures that are not accessible via traditional manufacturing processes and has found specific applications in tissue engineering and high-strength materials production. SLA is one such approach, which typically utilizes ultraviolet light to cure a photoactive resin onto a vertically moving plate. Stereolithography is traditionally realized by printing successive 2D layers between the vertically moving plate and the bottom of the vat in order to build up a three-dimensional (3D) object. This process is time-consuming as each layer must be mechanically cleaved from the bottom of the resin vat before another layer can be printed. Recent advances employ an oxygen “dead zone” between the bottom of the vat and the polymerized object to achieve continuous liquid interface production (CLIP). Because the polymerizing object is no longer in contact with the bottom of the resin vat, mechanical cleavage is not necessary, making CLIP a continuous stereolithographic process. CLIP is being used by Carbon 3D to manufacture parts approximately 100 times faster than traditional SLA methodologies. At these print speeds, however, the heat generated from the exothermic polymerization reactions can result in deformation of the printed object.
HARP utilizes a circulating fluorinated oil layer below the resin to remove heat at the boundary between the oil and the resin, cooling the system (Figure 2). The fluorinated oil is circulated at a rate that supports the formation of a solid-liquid slip boundary, and therefore, low adhesion between the printed object and the transparent vat. The slip boundary ensures uniformity of both topology and temperature across the interface and allows for continuous printing but at substantially higher throughputs than CLIP. The heat dissipation is a consequence of the direct contact between the fluorinated oil and the hot, polymerizing resin, since heat is effectively transferred from the resin to the oil. The hot oil is then flowed out of the reaction bath, cooled, filtered, and subsequently reintroduced into the system. Thus, control over the temperature of the system is attained. Even the printing of small structures via a SLA process at high-throughput without cooling results in temperatures at which deformation of the desired structure occurs (Figure 3A). In contrast, when HARP is used with cooling, markedly decreased temperatures are observed without a reduction in part quality (Figure 3C). HARP is also compatible with traditional stereolithographic resins; this has been demonstrated with polyurethane acrylate, butadiene rubber, and silicon carbide ceramic.  At the time of writing, HARP had printed the largest structure based on SLA 3D printing (0.30 x 0.30 x 1.2-meters) to date in approximately three hours (Figure 1).
Professor Chad Mirkin, Dr. James Hedrick, and Dr. David Walker founded Azul3D (previously CDJ Technologies) for the purpose of commercializing the HARP platform.


Projection micro-stereolithography

Projection micro-stereolithography (PµSL) adapts 3D printing technology for micro-fabrication. Digital micro display technology provides dynamic stereolithography masks that work as a virtual photomask. This technique allows for rapid photopolymerization of an entire layer with a flash of UV illumination at micro-scale resolution. The mask can control individual pixel light intensity, allowing control of material properties of the fabricated structure with desired spatial distribution.
Materials include polymers, responsive hydrogels, shape memory polymers and bio-materials.
Introduction.
The micro electro-mechanical systems (MEMS) is developing quickly in the past 30 years. Relying on the integration of sensors and actuators, MEMS always demand cheaper, easier and more precise method to fabricate micro size 3-D structures using different materials such as polymers, ceramics and semiconductor materials. The appearance of the Projection Micro-stereolithography improves the development of MEMS by achieving most of the requirements above. This invention is based on the stereolithography (3D printing), which developed by Charles Hull in 1984. This machine is primarily used to fabricate soft materials such as hydro gels and polymers. The basic theory behind this invention is using UV light to cure the solution, which consists initiators, monomers and absorbers, to form each layer of materials. Under the exposure of UV light, the initiators are transferred into the radicals. Radicals connect monomers together to begin the polymerization process. The absorbers are mixed with monomers to control the depth of UV light penetration. This chemical process allows the areas under UV exposure to become solid state polymers.
History.
At first, all micro size stereolithography method utilized the same method as the macro size stereolithography that they direct write materials on the base. The first micro size stereolithography that use the UV light to cure the liquid resin surface is developed by professor Ikuta and Hirowatari in 1993. This fabrication approach is the prototype of today's projection micro-stereolithography. Compared with previous direct writing fabrication methods, this approach has the advantage that it can fabricate each layer simultaneously which increases the yield rate for large production. At that time, 2D shape data was obtained in a CAD system. The 2D data is used to fabricate 2D sliced planes in the liquid. Therefore, several 2D planes have to be made in the CAD system for complicated structures. This stereolithography can be used to fabricate both polymers and metals. Metals are fabricated using the casting process after a polymer mold is made. Although improves the yield rate, this method requires a mask for each layer of the final product, which increases process time and cost. Therefore, the fabricate technology is developed again that the masks are replaced by the micromirror display device, which is similar to the projector in our daily life. The micromirror display provides a dynamic mask that can change the patterns electronically. Since multiple masks are displaced by one mask, the processing time and fabrication cost are greatly decrease.
Process.
The dynamic mask defines the beam. The beam is focused on the surface of a UV-curable polymer resin through a projection lens that reduces the image to the desired size. Once a layer is polymerized, the stage drops the substrate by a predefined layer thickness, and the dynamic mask displays the image for the next layer on top of the preceding one. This proceeds iteratively until complete. The process can create layer thickness on the order of 400 nm.
Sub 2 µm horizontal and sub-1 µm vertical resolutions have been achieved, with sub-1 µm feature sizes. Process can work at ambient temperature and atmosphere, although increased nitrogen improves polymerization Production rates of 4 cu mm/hr have been achieved, depending on resin viscosity.
Materials can be easily switched during fabrication, enabling integration of multiple material elements in a single process.
Applications.
Applications include fabricating microactuators, creating molds, electroplating or (with resin additives) ceramic items, including micro-bio reactors to support tissue growth, micromatrices for drug delivery and detection and biochemical integrated circuits to simulate biological systems.
Microactuator.
Inspired by Mimosa pudica, the leaf of this actuator can swell upon the external stimulations such as solvents, temperature and light. In order to control the motion of this actuator, microfluidic channels are embedded inside the leaf of this actuator. With both complex external geometries and internal structures, this soft microactuator can be fabricated using Projection Micro-stereolithography, which is one of the easiest ways to obtain this complex 3D structures. The CAD mold of this actuator is generated in a computer. The sliced 2D images are obtained next. Each 2D image is then projected by the micromirror display and go through the lens to a desired size to the surface of the polymer resin. Since Projection Micro-stereolithography is time-saving, the same experiment can be done on different liquid soft materials in order to learn the swelling effect of them. Based on this contraction and extension of materials caused by a small drop of solvent or a small change in environmental conditions, this microactuator can mimic the motion of the human muscle and can be used on many soft robotic applications.
Artificial Tissue.
Many reconstructive surgery procedures require new tissues when the original tissues are removed because of illnesses. One way to generate this new tissue is to take one part of tissue from another part of the human body and transfer it to the new site. However, this method causes damage to other organs while generating new tissues. Therefore, fabricating artificial tissues is a preferred approach to solve this problem. The major limitation of this artificial tissue is the absence of the capillary system to transport nutrient and oxygen like the circulatory systems in living organisms. With the ability to fabricate complex 3D structures, the Projection Micro-stereolithography may provide one of the best solutions to this tissue. Like the microactuator, the mold of the artificial tissue is made by CAD. Then the CAD mold is transferred to 2D images and projected to the surface of the polymer resin through a lens. The capillary system is embedded in the tissue during the mold designing process in the CAD mold. The polymer used in fabricating the tissue is semi-permeable, which allows the nutrient and oxygen in the capillary system go into the tissue during the transportation process. The capillary system is shown to have growth promoting function in yeast cells, which illustrate the viability of this artificial tissue.


Channel-stopper

In semiconductor device fabrication, channel-stopper or channel-stop is an area in semiconductor devices produced by implantation or diffusion of ions, by growing or patterning the silicon oxide, or other isolation methods in semiconductor material with the primary function to limit the spread of the channel area or to prevent the formation of parasitic channels (inversion layers).


Plaster mold casting

Plaster mold casting is a metalworking casting process similar to sand casting except the molding material is plaster of Paris instead of sand. Like sand casting, plaster mold casting is an expendable mold process, however it can only be used with non-ferrous materials. It is used for castings as small as to as large as . Generally, the form takes less than a week to prepare. Production rates of 1–10 units/hr can be achieved with plaster molds.
Parts that are typically made by plaster casting are lock components, gears, valves, fittings, tooling, and ornaments.
Details.
The plaster is not pure plaster of Paris, but rather has additives to improve green strength, dry strength, permeability, and castability. For instance, talc or magnesium oxide are added to prevent cracking and reduce setting time; lime and cement limit expansion during baking; glass fibers increase strength; sand can be used as a filler. The ratio of ingredients is 70–80% gypsum and 20–30% additives.
The pattern is usually made from metal, however rubber molds may be used for complex geometry; these molds are called s. For example, if the casting includes reentrant angles or complex angular surfaces then the rubber is flexible enough to be removed, unlike metal. These molds are also inexpensive, reusable, more accurate than steel molds, fast to produce, and easy to change.
Typical tolerances are for the first and 0.02 mm per additional centimeter (0.002 in per additional inch). A draft of 0.5 to 1 degree is required. Standard surface finishes that are attainable are 1.3 to 4 micrometers (50–125 μin).
Process.
First, the parting line is determined - either simple two part or more complex (3 or more). A box is made around the pattern to hold the plaster. Then plaster is mixed and the pattern is sprayed with a thin film of parting compound also called a release agent to prevent the plaster from sticking to the pattern. The plaster is then poured over the pattern and the box holding the plaster and pattern is vibrated by mechanical means in order to fill all gaps and to release air bubbles. The plaster sets, usually in about 15 minutes, and the pattern is removed. The mold is then baked, between and , to remove any excess water. The dried mold is then assembled, preheated, and the metal poured. Finally, after the metal has solidified, the plaster is broken from the cast part. The mold is usually damaged from the metal so reusing is usually not done. Discarded plaster can be recycled by grinding but care must be used since silica dust causes lung damage.
Advantages and disadvantages.
Plaster mold casting is used when an excellent surface finish and good dimensional accuracy is required. Because the plaster has a low thermal conductivity and heat capacity, the metal cools more slowly than in a sand mold, which allows the metal to fill thin cross-sections; the minimum possible cross-section is . This results in a near net shape casting, which can be a cost advantage on complex parts. It also produces minimal scrap material.
The major disadvantage of the process is that it can only be used with lower melting temperature non-ferrous materials, such as aluminium, magnesium, zinc and sometimes copper alloys. The most commonly used material is aluminium. The maximum working temperature of plaster is , so higher melting temperature materials would melt the plaster mold. Also, the sulfur in the gypsum reacts with iron, making it unsuitable for casting ferrous materials.
Another disadvantage is that its long cooling times restrict production volume. Onetime molds are often quenched in water but only after completing solidification so hot metal does not fly everywhere. Proper quenching can aid in mold removal and it makes some alloys stronger.
Plaster is not as stable as sand, so it is dependent on several factors, including the consistency of the plaster composition, pouring procedures, and curing techniques. If these factors are not closely monitored the mold can be distorted, shrink upon drying, have a poor surface finish, or fail completely.


Mechanical plating

Mechanical plating, also known as peen plating, mechanical deposition, or impact plating, is a plating process that imparts the coating by cold welding fine metal particles to a workpiece. Mechanical galvanization is the same process, but applies to coatings that are thicker than . It is commonly used to overcome hydrogen embrittlement problems. Commonly plated workpieces include nails, screws, nuts, washers, stampings, springs, clips, and sintered iron components.
The process involves tumbling the workpieces with a mixture of water, metal powder, media, and additives. Common coating materials are zinc, cadmium, tin, copper, and aluminium.
Invented by the Tainton Company in the 1950s, it was further developed by the 3M company.
Process.
The process begins with a descaling and removing soil from the workpiece. This can be done in the tumbler or in a separate cleaning system. After cleaning, the parts are prepared by combining them with water, medium, and a surface conditioner. The surface conditioner lightly coats the workpiece in copper, while the medium removes any residual mill scale or oxides. Finally, accelerators, promoters and metal powder are added to the mix. The accelerators and promoters provide the proper chemical environment for the plating to occur, such as the maintenance of a pH level of 1 to 2 to prevent oxidation and promote adhesion. The medium that is already in the mixture cold welds the metal powder to the workpiece through impacts that are induced by the tumbling action of the tumbler. At this point the surface finish is typically matte to a semi-bright finish, however the finish can be improved with a water polish. The time required for the above process is approximately 50 minutes.
For some thinly coated workpieces a chromate passivation is necessary. Finally, the workpiece, whether passivated or not, is dried.
The medium material is usually soda lime glass or a ceramic. It is usually spherical in form, but angular shapes are also used. For plating, medium usage is usually 1 part medium for every workpiece, but for galvanization the ratio is 2:1. However, various sized media are used in each batch with a typical batch consisting of 50% sized beads, 25% sized beads, and 25% sized beads. The smaller media are omitted when the workpiece has a cavity that the medium can get caught in, such as a fastener's recessed head. Note that the medium is reused many times.
This process works better if the workpieces' surface finish is slightly rough.
Equipment.
The most important piece of equipment in the process is the "tumbler". It is constructed of steel or stainless steel and lined with an acid and abrasion resistant material, such as neoprene, polypropylene, and polybutylene. The barrel sizes range from , however the working volume is only 25 to 35% of the total volume. For most plating applications the tumbler is rotated at 60 RPM, however it can vary. If the speed is too fast then lumpy deposits will form on the workpieces, but if the speed is too slow then the metal powder will not deposit onto the workpiece.
The "separator" separates the coated workpieces from the medium after coating. It can be as simple as a screen with water nozzles or as complicated as a vibratory system with magnetic separators. A "medium handling machine" then takes the separated medium and transports it to a storage tank for reuse.
The separated workpieces are then taken to a "dryer" to remove any moisture. Usually centrifugal dryers are used, however oven are used for larger parts or loads.
Advantages and disadvantages.
The greatest advantage of the process is its ability to overcome hydrogen embrittlement problems, which is important for workpieces that have a hardness greater than HRC 40. Note that there still is some embrittlement of the workpiece. While this process does not cause problems with hydrogen embrittlement, and electroplating does, it still offers equivalent corrosion protection. There is a great cost savings in using mechanical plating over electroplating on hardened workpieces, because the electroplating processes requires a pre- and post-plating operation to overcome hydrogen embrittlement problems. Moreover, because mechanical plating occurs at room temperature there is no tempering of hardened workpieces.
Another advantage is that mechanical plating evenly coats all surfaces and features, unlike electroplating which has issues plating recesses. Mechanical plating can evenly coat up to 75 μm thick. For thicker plating mechanical plating is especially cost advantageous versus electroplating, because the cycle time does not increase much for the thicker plating, unlike electroplating.
One of the disadvantages is the processes size limitations. Workpieces heavier than can be damaged by the process, while flat lightweight workpieces tend to stick together so they are not properly plated.


START Lab

START Lab Inc. (株式会社スタート ・ ラボ; "Sony Taiyo Yuden Advanced Recording Technology Laboratory") is a joint venture of Sony Corporation and Taiyo Yuden Co., Ltd. The headquarters are in Chiyoda, Tokyo.
START Lab, founded in June 1989, was active in the optical media business. Initially intended to produce small-scale runs of CDs for business customers on the basis of newly developed CD-R technology, it pioneered the sale of CD-R media to consumers. The current president is Masanori Kimizuka. 50.1% of START Lab is owned by Sony, 49.9% is owned by Taiyo Yuden.
START Lab ceased operations in March 2016 after parent company Taiyo Yuden ended production of storage media.
Well-known product lines included the That's consumer media, the That's CD-R/DVD-R for master product line, and the CD/DVD error checkers (ES-50, ES-70, ES-1000 rebranded Almedio model).


Velocette KTT Mk VIII

The Velocette KTT Mk VIII is a British racing motorcycle made by Veloce, Ltd. who built motorcycles named the Velocette. The Mk VIII KTT was ultimate development of their "K" series of overhead-camshaft 350cc machines introduced in 1925, and the "TT" designation indicated a production racing motorcycle, and a near replica of the factory race team machines. Production continued until 1950.
Development.
The final development of the Velocette KTT, the Mk VIII KTT was introduced in 1938 at that year's Earls Court Show, and was the first motorcycle to use the now-conventional swinging-arm rear fork with a shock absorber unit (in this case, an oleo-pneumatic unit built by the Oleo Strut Co. of England). The rear suspension system was designed by Veloce development engineer Harold Willis, and was inspired by the Oleo strut landing gear on the DeHavilland Hornet he borrowed at the Midland Aero Club, while his beloved DeHavilland 'Moth' was undergoing repair. Contact with the Oleo company led to several pairs of air shocks built for Veloce in 1936, for which the factory's racing rigid-frame racers (similar to the Mark VII KTT) were adapted with a swinging-fork rear end and bolt-on subframe for the seat. The experimental first swinging-arms used an adapted steering head lug turned sideways, with the cup-and-cone bearings retained. Production Mark VIII KTTs used a more conventional bronze bush and trunnion shaft pivot for the one-piece rear fork. The first experimental swing-arm machines were raced by the factory in the 1937 season, and introduced as the Mark VIII KTT the next year, for sale to the public.
The Mark VIII KTT was offered from 1938 - 1950, after which Veloce closed its racing department.


Interfering thread nut

An interfering thread nut is a type of locknut that has an undersized root diameter. This creates an interference between the nut and the fastener, plastically deforming the threads on the fastener. Due to this deformation they are usually only used on permanent or semi-permanent installations.
A variation of this nut is the tapered thread nut. It utilizes a tapered thread to achieve the interference. The nut goes on easily, because the thread diameter starts at a standard size; as the nut is further threaded on it begins to lock, much like a distorted thread locknut.


Swage nut

A swage nut or self-clinching nut is a type of nut or threaded insert that is used on sheet metal.
It permanently anchors itself to the sheet metal by swaging the surrounding material. Generally, the swage nut is made of a hard metal such as stainless steel, which is inserted into a pre-drilled hole in a softer ductile material such as aluminum. The inserted shank has three diameters: a main shaft which fits the hole closely, a thin smaller-diameter undercut, and a larger-diameter serrated clinching ring. Forcing the clinching ring into softer material, with an arbor press or by tightening a screw through the hole, causes it to plastically deform (swage) into the annular recess in the shank. This locks the nut into the hole. The knurling on the clinching ring is not necessary for this step, but prevents the nut from rotating after installation.
This is a popular method for adding strong, load-bearing threads to a relatively thin piece of soft sheet metal.
Self-clinching nuts are described in National Aerospace Standard NASM45938 which supersedes military specification MIL-N-45938
History.
Albert Spokes filed for a U.S. patent on the swage nut in early 1958. The swage nut is descended from an older idea, the clinch nut. Clinch nuts incorporate a tubular shaft that fits through the part to be attached and is clinched or riveted in place from the opposite side.


Clip-on nut

A clip-on nut, also known as a sheet metal nut or a speed nut (but this is ambiguous, see speed nut), is a type of nut designed to be clipped to sheet metal. It is a type of captive nut commonly made as a cage nut.
Types.
They come in many forms based upon: where they clip on, shape, and type of thread. Each clip-on nut is designed for only a small range of sheet metal gauges (thicknesses). They are usually made from spring steel.
G-nut.
A G-nut, or G-style nut, is shaped like a "G" and clips to the edge of a sheet metal object. It is different from all of the other types in that it is meant to clip over a small flange on the edge of the sheet metal. The threads are from an integrated nut that has a special boss to sit in a hole in the sheet metal.
J-nut.
A J-nut is a nut that clips to the edge of the sheet metal. It is named after the way it is shaped; the thread is on the long side of the "J". The thread may either be of a speed nut form or have an integrated hex or square nut. Due to the short retaining leg the nut is allowed to float more, which can help with misalignment, but the nut is free to un-clip from the sheet metal as well.
S-nut.
An S-nut, or S-style nut, is shaped like an "S". It is designed to clip on the edge of a sheet metal object. The threads are provided by an integrated nut.
Square style.
A square style clip-on nut does not clip onto the edge of the sheet metal, but rather the edges of a square hole or slot. It is a square nut that has a sheet metal retainer that protrudes down two sides of the nut. These legs are formed to have lips that grab onto the sheet metal object. Prior to tightening the nut, it can float in the hole or slot, but when the nut is tightened it presses the lips of the retainer out and anchors itself in place.
U-nut.
A U-nut is very similar to a J-nut except that both legs are the same length. Because of this a retaining clip is usually formed on the leg without the threads. This helps keep the nut in place while not screwed down. The thread may be of a speed nut style, integrated nut, or have an extruded portion that is tapped. There are "standard" and "wide-panel" versions; the standard version has a solid hinge section, whereas the wide-panel version has a longer hinge with the center section cut-away to allow for easier installation.


Reliability (semiconductor)

Reliability of semiconductor devices can be summarized as follows:
Design factors affecting semiconductor reliability include: voltage, power, and current derating; metastability; logic timing margins (logic simulation); timing analysis; temperature derating; and process control.
Methods of improvement.
Reliability of semiconductors is kept high through several methods. Cleanrooms control impurities,
process control controls processing, and burn-in (short term operation at extremes) and probe and test reduce escapes. Probe (wafer prober) tests the semiconductor die, prior to packaging, via micro-probes connected to test equipment. Final test tests the packaged device, often pre-, and post burn-in for a set of parameters that assure operation. Process and design weaknesses are identified by applying a set of stress tests in the qualification phase of the semiconductors before their market introduction e. g. according to the AEC Q100 and Q101 stress qualifications. Parts Average Testing is a statistical method for recognizing and quarantining semiconductor die that have a higher probability of reliability failures. This technique identifies characteristics that are within specification but outside of a normal distribution for that population as at-risk outliers not suitable for high reliability applications. Tester-based Parts Average Testing varieties include Parametric Parts Average Testing (P-PAT) and Geographical Parts Average Testing (G-PAT), among others. Inline Parts Average Testing (I-PAT) uses data from production process control inspection and metrology to perform the outlier recognition function.
Bond strength measurement is performed in two basic types: pull testing and shear testing. Both can be done destructively, which is more common, or non destructively. Non destructive tests are normally used when extreme reliability is required such as in military or aerospace applications.
Failure mechanisms.
Failure mechanisms of electronic semiconductor devices fall in the following categories


Plastic forming machine

Plastic forming machines, or plastic molding machines, were developed on the basis of rubber machinery and metal die-casting machines. After the inception of the polymer injection molding process in the 1870s, plastic-forming machines were rapidly developed up until the 1930s. With the gradual commercialization of plastic molding equipment, injection molding and extrusion molding became the most common industrialized processes. Blow molding is the third-largest plastic molding method after the injection molding and extrusion blow molding methods.
Types of plastic forming machine.
Plastic injection molding machine.
A plastic injection molding machine injects melted plastic into a mold to make solid plastic parts.
Plastic extrusion machine.
A plastic extrusion machine extrudes plastic in a continuous profile. The main machine is usually called the host, and its accompanying equipment are called the plastic auxiliary equipment. Plastic extruders can make plastic film/wrapping, packing tape, corrugated sheets, plastic lumber, pipes, tubes, insulated wire, monofilament and nets.
Plastic blow molding machine.
A plastic blow molding machine inflates a preform or parison inside of a mold to form hollow parts.
Thermoforming.
Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, and stamped to a specific shape in a 2-part mold. Or a vacuum can be used to pull the plastic sheet onto the mold in a simplified process known as vacuum forming. The excess material is trimmed off and recycled.
Rotational molding.
Rotational molding involves a heated hollow mold that is filled with a charge or shot weight of material. It is then slowly rotated (usually around two perpendicular axes), causing the softened material to disperse and stick to the walls of the mold forming a hollow part. In order to form an even thickness throughout the part, the mold rotates at all times during the heating phase, and then continues to rotate during the cooling phase to avoid sagging or deformation. Rotocasting is a variant of the process that uses self-curing or UV-curable resins (as opposed to thermoplastics) in an unheated mold.
See also.
Mold-A-Rama


Boutique manufacturing

Boutique manufacturing is a method used for the custom production of certain products in limited quantities by hand or with a restricted level of automation. Products produced this way often include ceramics, furniture, amplifiers, yachts, boats, leather goods or watches and jewellery among others. In industrial countries, boutique manufacturing is being selected generally for high class goods in upper price levels and only for single products or small batches.
Benefits and disadvantages.
The key advantages of boutique manufacturing in comparison to traditional factory manufacturing with batch fabrication, large or mass production are as follows:
Consequently, boutique manufacturing closes the gap between piece production and small batch/low volume production. The workflow organization of a boutique manufacturing entity can be a mixture of both – elements of jobbing or batch production, however involving higher standardization than the first one. Often boutique manufacturing workshop and factories are organized with single workplaces or production cells carrying out a number of subsequent production steps until completion of certain components or even the whole product. Flexibility and variety of products being able to produce in the entity therefore are much higher than with the more standardized method batch production.
However, with this method, manufacturing of larger quantities of unified products is not possible at reasonable costs. Serial fabrication or large production of goods then would be suitable alternative production methods involving higher grades of automation and standardization.