Microfactory

A microfactory either refers to a capital-light facility used for the local assembly of a complex product or system or a small (normally automated) factory for producing small quantities of products. The term was proposed by the Mechanical Engineer Laboratory (MEL) of Japan in 1990 and has recently been used to describe the approach of manufacturers like Arrival. The microfactory's main advantages are saving a substantial amount of space, energy, materials, time, and upfront capital costs.
Due to their reduced dimensions, microfactories are normally highly automated. They might contain automatic machine tools, assembly systems, quality inspection systems, material feed systems, waste elimination systems, a system to evaluate tool deterioration and a system to replace tools.
At least one proposed microfactory is being designed to make many of its own parts, i.e., a partially self-replicating machine.
A microfactory can also refer to a factory designed for flexible small batch production that can produce a wide variety of products as opposed to a single monolithic mass production type approach. Typically the manufacturing processes of microfactories take advantage of digital fabrication technology such as 3D printing and CNC machines in order to accomplish this. For example, Local Motors had microfactories in Phoenix, Ariz. and Knoxville, Tenn. The company built products, like the Rally Fighter prerunner sports car, in its microfactories.


Packaging engineering

Packaging engineering, also package engineering, packaging technology and packaging science, is a broad topic ranging from design conceptualization to product placement. All steps along the manufacturing process, and more, must be taken into account in the design of the package for any given product. Package engineering is an interdisciplinary field integrating science, engineering, technology and management to protect and identify products for distribution, storage, sale, and use. It encompasses the process of design, evaluation, and production of packages. It is a system integral to the value chain that impacts product quality, user satisfaction, distribution efficiencies, and safety. Package engineering includes industry-specific aspects of industrial engineering, marketing, materials science, industrial design and logistics. Packaging engineers must interact with research and development, manufacturing, marketing, graphic design, regulatory, purchasing, planning and so on. The package must sell and protect the product, while maintaining an efficient, cost-effective process cycle.
Engineers develop packages from a wide variety of rigid and flexible materials. Some materials have scores or creases to allow controlled folding into package shapes (sometimes resembling origami). Packaging involves extrusion, thermoforming, molding and other processing technologies. Packages are often developed for high speed fabrication, filling, processing, and shipment. Packaging engineers use principles of structural analysis and thermal analysis in their evaluations.
Education.
Some packaging engineers have backgrounds in other science, engineering, or design disciplines while some have college degrees specializing in this field.
Formal packaging programs might be listed as package engineering, packaging science, packaging technology, etc. BE, BS, MS, M.Tech and PhD programs are available. Students in a packaging program typically begin with generalized science, business, and engineering classes before progressing into industry-specific topics such as shelf life stability, corrugated box design, cushioning, engineering design, labeling regulations, project management, food safety, robotics, RFID tags, quality management, package testing, packaging machinery, tamper-evident methods, recycling, computer-aided design, etc.


Buchli drive

The Buchli drive is a transmission system used in electric locomotives. It was named after its inventor, Swiss engineer Jakob Buchli. The drive is a fully spring-loaded drive, in which each floating axle has an individual motor, that is placed in the spring mounted locomotive frame. The weight of the driving motors is completely disconnected from the driving wheels, which are exposed to movement of the rails.
First used in electric locomotives from the 1920s, the Buchli drive made possible the construction of faster and more powerful locomotives that required larger and heavier traction motors. The system minimises the impact on rail tracks due to the reduction in the overall unsprung weight. Although the drive was very successful though the 1930s, it is little used in modern locomotives, having been replaced with smaller, simpler drives that exhibit less imbalance and allow higher speeds.
Construction.
In a Buchli drive a driven gear wheel is securely fixed to the locomotive frame. Inside this gear wheel are two levers, coupled to gear segments that mesh with one another. The other end of the levers is coupled via universal joints to tension bars, which are then coupled via more universal joints to the driving rail wheel.
Vertical movement of the driving wheel results in the gear segments moving due to the internal mechanism, and the driving wheel can move in a horizontal or vertical direction with respect to the gear wheel, while still transferring the momentum of the gear wheel.
A disadvantage of the drive was the large number of moving parts, which demanded frequent lubrication and careful maintenance. As a result the Buchli drive system was mainly used on express train locomotives, as there were no other drive systems that gave the same performance at high speeds. However, at higher speeds the drive components became unbalanced, causing issues at speeds over 140 km per hour.
Standard design.
The Buchli drive was exported to other rail companies as one sided separate traction motor drive, usually with an inside frame.
The motor framework with the wheelset bearing is located between the wheel disks of the driving wheels. The gear wheel, which is housed in an auxiliary frame outside the driving wheels and is surrounded by a protective casing, is on one side of the driving wheels. Each gear wheel is driven by an individual traction motor, which is located above the gear wheel in the locomotive body.
With this implementation, a strongly one-sided weight distribution occurs in the underframe through the remote gear wheels. In order to maintain stability of the locomotive on the longitudinal axis, heavy equipment inside the locomotive body must be arranged on the opposite side of the drive equipment.
Locomotives with a Buchli drive also typically have an asymmetrical appearance: on one side, the bearings of the drive wheels are visible, on the other side, they are almost completely covered by the wheel cover box of the gear wheels.
Other designs.
In addition to the standard implementation, there were also the following variations:
Outside frame.
The engine framework with the driving wheel housing is outside the wheel disks of the driving wheels. The driving wheel is enclosed by a quill camped in the locomotive cabinet, on which the gear wheel sits. Examples included the Pennsylvania Railroad O1b, and the Deutsche Reichsbahn ET11.01.
Group drive.
The motor is arranged between the floating axles. A common pinion or a pinion on both motor end drives the gear wheels of the neighbouring axes. described this design, but vehicles implementing it are not known.
Bilateral drive.
The driving wheel is coupled with two gear wheels, and the motor has a pinion on both sides. The taps in the wheel disk are warped about 90 degrees against each other so that the drive imbalance can be reduced. This version of the driver was used for greater driving power.
However with this arrangement, there is the danger of mechanical stress in the drive components. Examples included the French express train locomotives: SNCF 2D2 5400, SNCF 2D2 5500, SNCF 2D2 9100.
Two motors per axis.
Two driving motors work on one common gear wheel, which is interconnected with a driving wheel. Examples include the Pennsylvania Railroad O1b.
Locomotive with Buchli drive.
Nearly 240 locomotives of the SBB with Buchli drive were in use for over sixty years. The SBB Ae 3/6I class locomotives were in operation from 1921 to 1994. French tracks had 100 express train locomotives using the Buchli drive, in service for fifty years.


Lapping film

Lapping film, in telecommunications, is a precision coated abrasive consumable mainly used for processing and polishing optical fiber connectors. It is made from a polyester base sheet, coated with precisely graded minerals such as diamond, aluminium oxide, silicon carbide, silicon oxide or cerium oxide. Lapping film is designed to provide a uniform, consistent finish on optical fiber connector end tips to ensure efficient light/signal transmission. It is available in 0.01-45 μm grades, with or without pressure-sensitive adhesive (PSA) backing.


Expanded polyethylene

Expanded polyethylene (aka EPE foam) refers to foams made from polyethylene. Typically it is made from expanded pellets ('EPE bead') made with use of a blowing agent, followed by expansion into a mold in a steam chest - the process is similar to that used to make expanded polystyrene foam.
Properties.
EPE foams are low density, semi-rigid, closed cell foam that are generally somewhere in stiffness/compliance between Expanded polystyrene and Polyurethane. Production of EPE foams is similar to that of expanded polystyrene, but starting with PE beads. Typical densities are with the lower figure being common. Densities as low as can be produced.
Base polymer for EPE foams range from Low-density polyethylene (LDPE) to High-density polyethylene (HDPE).
Co-polymers.
Expanded polyethylene copolymers (EPC) are also known - such as 50:50 (weight) materials with polystyrene. Though other properties are intermediate between the two bases, toughness for the copolymer exceeds either, with good tensile and puncture resistance. It is particularly applicable for re-usable products.
Production.
EPE foams were first manufactured in the 1970s.
Production of the PE beads is usually by extrusion, followed by chopping, producing a 'pellet'. Autoclave expansion is the most common route the bead foam. Butane or pentane is often used as a blowing agent (before 1992 CFCs may have been used). Depending on the specific process uses the beads may be cross-linked either by electron beam irradiation (see Electron beam processing), or by the addition of a chemical agent such as Dicumyl peroxide.
An alternate route (JSP Process) to the beads uses carbon dioxide as a blowing agent which is impregnated into the pellets in an autoclave at a temperature close to the plastic's crystalline melting point. The pellets are foamed by "flashing" into the (lower pressure) atmosphere to expand.
Finally molding is done by steam chest compression molding; usually the low pressure variant of the process is used, though the high pressure variant may be used for HDPE based EPE foams.
Uses.
Polyethylene bead foams (including) EPE can be used to replace both polystyrene foam, and both rigid and flexible polyurethane. Uses include cushioning applications, and impact absorption applications including packaging.
Consumption of polyethylene for PE foam was estimated at 114x106 kg in 2001. The majority was used for non-crosslinked foams, but crosslinked PE foams represented a significant (~ one third) fraction of demand. Use in protective packaging represented the largest use sector for such foams.


RepRap Snappy

The RepRap Snappy is an open-source fused deposition modeling 3D printer, part of the RepRap project, it is the most self replicating 3D printer in the world.
The RepRap Snappy is designed to address the core goal of the RepRap project of creating a "'general-purpose self-replicating manufacturing machine"'. The RepRap Snappy is able to create 73% of its own parts by volume with a design that eliminates as many of the non 3D printed parts as possible including belts and bearings which are replaced with a rack and pinion system. The name Snappy comes from the use of snap fit connectors used on the small printed parts to construct larger pieces, this both cuts down on the use of non 3D printed parts and means a smaller build volume is needed on the machine producing the parts. The only non self replicating parts on the printer are the motors, electronics, a glass build plate and one 686 bearing, the 3D printed parts take around 150 hours to create. The RepRap Snappy received an honourable mention in the Uplift Prize Grand Personal Manufacturing Prize.


Severe plastic deformation

Severe plastic deformation (SPD) is a generic term describing a group of metalworking techniques involving very large strains typically involving a complex stress state or high shear, resulting in a high defect density and equiaxed "ultrafine" grain (UFG) size (d nanocrystalline (NC) structure (d < 100 nm).
History.
The significance of SPD was known from the ancient times, at least during the transition from the Bronze Age to the Iron Age, when repeated hammering and folding was employed for processing strategic tools such as swords. The development of the principles underlying SPD techniques goes back to the pioneering work of P.W. Bridgman at Harvard University in the 1930s. This work concerned the effects on solids of combining large hydrostatic pressures with concurrent shear deformation and it led to the award of the Nobel Prize in Physics in 1946. Very successful early implementations of these principles, described in more detail below, are the processes of equal-channel angular pressing (ECAP) developed by V.M. Segal and co-workers in Minsk in the 1970s and high-pressure torsion, derived from Bridgman's work, but not widely developed until the 1980s at the Russian Institute of Metals Physics in modern-day Yekaterinburg.
Some definitions of SPD describe it as a process in which high strain is applied without any significant change in the dimensions of the workpiece, resulting in a large hydrostatic pressure component. However, the mechanisms that lead to grain refinement in SPD are the same as those originally developed for mechanical alloying, a powder process that has been characterized as "severe plastic deformation" by authors as early as 1983. Additionally, some more recent processes such as asymmetric rolling, do result in a change in the dimensions of the workpiece, while still producing an ultrafine grain structure. The principles behind SPD have even been applied to surface treatments.
Methods.
Equal channel angular Pressing.
Equal channel angular extrusion (ECAE, sometimes called Equal channel angular pressing, ECAP) was developed in the 1970s. In this process, a metal billet is pressed through an angled (typically 90 degrees) channel. To achieve optimal results, the process may be repeated several times, changing the orientation of the billet with each pass. This produces a uniform shear throughout the bulk of the material.
High pressure torsion.
High pressure torsion (HPT) can be traced back to the experiments that won Percy Bridgman the 1946 Nobel Prize in Physics, though its use in metal processing is considerably more recent. In this method, a disk of the material to be strained is placed between 2 anvils. A large compressive stress (typically several gigapascals) is applied, while one anvil is rotated to create a torsion force. HPT can be performed unconstrained, in which the material is free to flow outward, fully constrained, or to some degree between in which outward flow is allowed, but limited.
Accumulative roll bonding.
In accumulative roll bonding (ARB), 2 sheets of the same material are stacked, heated (to below the recrystallization temperature), and rolled, bonding the 2 sheets together. This sheet is cut in half, the 2 halves are stacked, and the process is repeated several times. Compared to other SPD processes, ARB has the benefit that it does not require specialized equipment or tooling, only a conventional rolling mill. However, the surfaces to be joined must be well-cleaned before rolling to ensure good bonding.
Repetitive corrugation and straightening.
Repetitive corrugation and straightening (RCS) is a severe plastic deformation technique used to process sheet metals. In RCS, a sheet is pressed between two corrugated dies followed by pressing between two flat dies. RCS has gained wide popularity to produce fine grained sheet metals. Endeavors to improve this technique lead to introduce Repetitive Corrugation and Straightening by Rolling (RCSR), a novel SPD method. Applicability of this new method approved in the various materials.
Asymmetric rolling.
In asymmetric rolling (ASR), a rolling mill is modified such that one roll has a higher velocity than the other. This is typically done with either independent speed control or by using rolls of different size. This creates a region in which the frictional forces on the top and bottom of the sheet being rolled are opposite, creating shear stresses throughout the material in addition to the normal compressive stress from rolling. Unlike other SPD processes, ASR does not maintain the same net shape, but the effect on the microstructure of the material is similar.
Mechanical alloying.
Mechanical alloying/milling (MA/MM) performed in a high-energy ball mill such as a shaker mill or planetary mill will also induce severe plastic deformation in metals. During milling, particles are fractured and cold welded together, resulting in large deformations. The end product is generally a powder that must then be consolidated in some way (often using other SPD processes), but some alloys have the ability to consolidate "in-situ" during milling. Mechanical alloying also allows powders of different metals to be alloyed together during processing.
Surface treatments.
More recently, the principles behind SPD have been used to develop surface treatments that create a nanocrystalline layer on the surface of a material. In the surface mechanical attrition treatment (SMAT), an ultrasonic horn is connected to an ultrasonic (20 kHz) transducer), with small balls on top of the horn. The workpiece is mounted a small distance above the horn. The high frequency results in a large number of collisions between the balls and the surface, creating a strain rate on the order of 102–103 s−1. The NC surface layer developed can be on the order of 50 μm thick. The process is similar to shot peening, but the kinetic energy of the balls is much higher in SMAT.
An ultrasonic nanocrystalline surface modification (UNSM) technique is also one of the newly developed surface modification technique. In the UNSM process, not only the static load, but also the dynamic load are exerted. The processing is conducted striking a workpiece surface up to 20K or more times per second with shots of an attached ball to the horn in the range of 1K-100K per square millimeter. The strikes, which can be described as cold-forging, introduce SPD to produce a NC surface layer by refining the coarse grains until nanometer scale without changing the chemical composition of a material which render the high strength and high ductility. This UNSM technique does not only improve the mechanical and tribological properties of a material, but also produces a corrugated structure having numerous of desired dimples on the treated surface.
Applications.
Most research into SPD has focused on grain refinement, which has obvious applications in the development of high-strength materials as a result of the Hall-Petch relation. Conventionally processed industrial metals typically have a grain size from 10–100 μm. Reducing the grain size from 10 μm to 1 μm can increase the yield strength of metals by more than 100%. Techniques that use bulk materials such as ECAE can provide reliable and relatively inexpensive ways of producing ultrafine grain materials compared to rapid solidification techniques such as melt spinning.
However, other effects of SPD, such as texture modification also have potential industrial applications as properties such as the Lankford coefficient (important for deep drawing processes) and magnetic properties of electrical steel are highly dependent on texture.
Processes such as ECAE and HPT have also been used to consolidate metal powders and composites without the need for the high temperatures used in conventional consolidation processes such as hot isostatic pressing, allowing desirable characteristics such as nanocrystalline grain sizes or amorphous structures to be retained.
Some known commercial application of SPD processes are in the production of Sputtering targets by Honeywell and UFG titanium for medical implants.
Grain refinement mechanism.
The presence of a high hydrostatic pressure, in combination with large shear strains, is essential for producing high densities of crystal lattice defects, particularly dislocations, which can result in a significant refining of the grains. Grain refinement in SPD processes occurs by a multi-step process:
The mechanism by which the subgrains rotate is less understood. Wu "et al." describe a process in which dislocation motion becomes restricted due to the small subgrain size and grain rotation becomes more energetically favorable. Mishra "et al." propose a slightly different explanation, in which the rotation is aided by diffusion along the grain boundaries (which is much faster than through the bulk).
F.A. Mohamad has proposed a model for the minimum grain size achievable using mechanical milling. The model is based on the concept that the grain size is dependent on the rates at which dislocations are generated and annihilated. The full model is given by
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While the model was developed specifically for mechanical milling, it has also been successfully applied to other SPD processes. Frequently only a portion of the model is used (typically the term involving the stacking fault energy) as the other terms are often unknown and difficult to measure. This is still useful as it implies that all other things remaining equal, reducing the stacking fault energy, a property that is a function of the alloying elements, will allow for better grain refinement. A few studies, however, suggested that despite the significance of stacking fault energy on the grain refinement at the early stages of straining, the steady-state grain size at large strains is mainly controlled by the homologous temperature in pure metals and by the interaction of solute atoms and dislocations in single-phase alloys.


Roll bonding

Roll bonding is a solid state, cold welding process, obtained through flat rolling of sheet metals. In roll bonding, two or more layers of different metals are passed through a pair of flat rollers under sufficient pressure to bond the layers. The pressure is high enough to deform the metals and reduce the combined thickness of the clad material. The mating surfaces must be previously prepared (scratched, cleaned, degreased) in order to increase their friction coefficient and remove any oxide layers.
The process can be performed at room temperature or at warm conditions. In warm roll bonding, heat is applied to pre-heat the sheets just before rolling, in order to increase their ductility and improve the strength of the weld. The strength of the rolled bonds depends on the main process parameters, including the rolling conditions (entry temperature of the sheets, amount of thickness reduction, rolling speed, etc.), the pre-rolling treatment conditions (annealing temperature and time, surface preparation techniques, etc.) and the post-rolling heat treatments.
Applications.
The applications of roll bonding can be used for cladding of metal sheets, or as a sub-step of the accumulative roll bonding. Bonding of the sheets can be controlled by painting a pattern on one sheet; only the bare metal surfaces bond, and the un-bonded portion can be inflated if the sheet is heated and the coating vaporizes. This is used to make heat exchangers for refrigeration equipment.


Production control

Within supply chain management and manufacturing, production control is the activity of monitoring and controlling any particular production or operation. Production control is often run from a specific control room or operations room. With inventory control and quality control, production control is one of the key functions of operations management.
Overview.
Production control is the activity of monitoring and controlling a large physical facility or physically dispersed service. It is a "set of actions and decision taken during production to regulate output and obtain reasonable assurance that the specification will be met." The American Production and Inventory Control Society, nowadays APICS, defined production control in 1959 as:
Production planning and control in larger factories is often run from a production planning department run by production controllers and a production control manager. Production monitoring and control of larger operations is often run from a central space, called a control room or operations room or operations control center (OCC).
The emerging area of Project Production Management (PPM), based on viewing project activities as a production system, adopts the same notion of production control to take steps to regulate the behavior of a production system where in this case the production system is a capital project, rather than a physical facility or a physically dispersed service.
Production control is to be contrasted with project controls. As explained, project controls have developed to become centralized functions to track project progress and identify deviations from plan and to forecast future progress, using metrics rooted in accounting principles.
Types.
One type of production control is the control of manufacturing operations.
Management of real-time operational in specific fields.
Communist countries had a central production control institute, where the agricultural and industrial production for the whole nation was planned and controlled.
In Customer Care environments production control is known as Workforce Management (WFM). Centralized Workforce Management teams are often called Command Center, Mission Control or WFM Shared Production Centers.
Related types of control in organizations.
Production control is just one of multiple types of control in organizations. Most commons other types are:


Rotary transfer machine

A rotary transfer machine is a machine tool, typically for metal working by machining, comprising a large indexing table with machining stations surrounding the table. Such rotary transfer machines are used for producing a large number of parts in fairly short cycle times.
Operation.
In rotary transfer machines, the workpieces are located and clamped in pallet type fixtures that are indexed in a circular path. During one cycle, sequential machining operations are performed simultaneously on the workpieces. The indexed table turns vertically or horizontally, and its movement could be continuous or intermittent. As the indexing table turns, the subsequent machining operation is repeated on the workpiece which was just machined by the previous station. This design combines automated part feed with simultaneous operations, enabling rapid completion of parts.
Applications.
Rotary transfer machines are commonly used for the mass-production of metal parts in the automotive industry and for pneumatic and hydraulic fittings. The parts can range from simple to complex, depending on the layout of the machining tool, which is often custom-designed for the manufacturing of a single part or family of parts. Rotary arrangement presents a compact arrangement that saves floor space. The annual production capacity of one rotary transfer machine can range from 100'000 units to tens of millions of units.
Rotary transfer machines can generally cope with all standard machining operations like turning, milling, drilling, reaming, threading, recessing, marking, deburring, etc... for sizes ranging more or less from a fingernail up to a backpack.


Retaining ring

A retaining ring is a fastener that holds components or assemblies onto a shaft or in a housing/bore when installed - typically in a groove - for one time use only. Once installed, the exposed portion acts as a shoulder which retains the specific component or assembly. Circlips are a type of retaining ring.
Circular push-on retaining rings may be installed in applications where there is no groove.
Retaining rings are typically made from carbon steel, stainless steel or beryllium copper and may feature a variety of finishes for aesthetics and corrosion protection depending on the type of environment in which they are used.
Types.
There are four main types of retaining rings available, each of which may then be broken down into sub-types depending on unique application needs:
Tapered section retaining rings.
Tapered section retaining rings decrease symmetrically from the center to the free ends, remaining circular when contracted or expanded within the limits of normal use. This assures contact with the groove along the entire periphery of the ring. These rings may be installed axially (horizontally along the center point of an axis) or radially (externally along the radius of a circle). Depending on the size of the ring in question, it may be manufactured in one of two ways:
Axially assembled.
Axially assembled retaining rings are installed into machined grooves in housings/bores (internal) or on shafts (external). These rings are manufactured with lug holes—small holes in the lugs of both axial internal and external retaining rings—that are used to install/remove them, using pliers designed for this purpose.
Inverted retaining rings.
Inverted retaining rings are a variation of axially assembled rings in which the lug holes are inverted to fit in the bottom of the groove. Inverting the lugs allows greater clearance on a shaft or in a housing and forms a higher uniform shoulder good for retaining bearings and other components with large corner radii or chamfers.
Beveled retaining rings.
Beveled retaining rings feature a 15° beveled or angled edge. This angle allows the ring to wedge itself between the groove and the retained part until it can go no farther, effectively “locking” everything in place. Think of placing a cork in a bottle. The cork is forced into the opening until it is wedged as far into the opening as possible. The same thing happens when a beveled retaining ring is installed into an application. The ring is wedging itself into place between the groove wall and the retained part, resulting in what is referred to as rigid end-play take-up.
Bowed retaining rings.
Bowed retaining rings are curved versions of standard flat internal and external retaining rings and exert a pre-load on an assembly when installed in the groove. This takes up the end-play and acts like a spring, which keeps the assembly in compression.
In manufacturing, parts can not be produced to an exact dimension; as a result, if they are made on the low side of the tolerance, they will be loose or have play on the shaft when a standard ring is installed. If they are made on the high side of the tolerance, they will extend further into the groove and prevent a standard ring from being fully installed. Compensating for accumulated tolerances is what bowed retaining rings are designed to do, by acting as a spring once installed into the groove.
Radially assembled.
Radially assembled retaining rings are installed externally into machined grooves on a shaft. These rings have no lug holes and must be installed using applicators.
Self-locking.
Self-locking retaining rings can be installed in a housing/bore or on a shaft that has not had a groove machined into it. Self-locking rings with no lug holes are impossible to remove without either destroying the ring or warping it out of specified tolerances.
Constant section retaining rings.
Constant section retaining rings (snap rings) feature a uniform, constant section. In other words, the material used to make the ring is the same width at any point along the circumference of the ring. When they are contracted or expanded, they take on an elliptical deformation. As a result, they contact the groove at three or more isolated points but never continuously around the periphery. These rings are made from either flat or round wire.
Spiral retaining rings.
Spiral retaining rings are axially installed into housings/bores (internal) or onto shafts (external), making 360° contact with the groove. Spiral retaining rings have no ears or lugs to interfere with the assembly. These rings are manufactured by coiling flat wire into the shape of the finished retaining ring. Spiral rings are provided with a removal notch to simplify the removal process. Spiral retaining rings can be economically produced in special alloys like stainless steel because the manufacturing process eliminates scrap.
No special tools are required for installation or removal. Duck bill pliers can be used in installing and removing external spiral rings.
Circular push-on.
A circular push-on ring resembles a toothed washer, commonly fabricated in metal. These are installed by pressing onto the end of a grooved shaft, until the nut's inner teeth snap into the groove. The use of push nuts avoids the cost of threading a nut onto the end of the shaft during the manufacturing process.
Protective finishes.
The following are various surface finished used on retaining rings:


Wave soldering

Wave soldering is a bulk soldering process used for the manufacturing of printed circuit boards. The circuit board is passed over a pan of molten solder in which a pump produces an upwelling of solder that looks like a standing wave. As the circuit board makes contact with this wave, the components become soldered to the board. Wave soldering is used for both through-hole printed circuit assemblies, and surface mount. In the latter case, the components are glued onto the surface of a printed circuit board (PCB) by placement equipment, before being run through the molten solder wave. Wave soldering is mainly used in soldering of through hole components.
As through-hole components have been largely replaced by surface mount components, wave soldering has been supplanted by reflow soldering methods in many large-scale electronics applications. However, there is still significant wave soldering where surface-mount technology (SMT) is not suitable (e.g., large power devices and high pin count connectors), or where simple through-hole technology prevails (certain major appliances).
Wave solder process.
There are many types of wave solder machines; however, the basic components and principles of these machines are the same. The basic equipment used during the process is a conveyor that moves the PCB through the different zones, a pan of solder used in the soldering process, a pump that produces the actual wave, the sprayer for the flux and the preheating pad. The solder is usually a mixture of metals. A typical leaded solder is composed of 50% tin, 49.5% lead, and 0.5% antimony. The Restriction of Hazardous Substances Directive (RoHS) has led to an ongoing transition away from 'traditional' leaded solder in modern manufacturing in favor of lead-free alternatives. Both tin-silver-copper and tin-copper-nickel alloys are commonly used, with one common alloy (SN100C) being 99.25% tin, 0.7% copper, 0.05% nickel and <0.01% germanium.
Fluxing.
Flux in the wave soldering process has a primary and a secondary objective. The primary objective is to clean the components that are to be soldered, principally any oxide layers that may have formed. There are two types of flux, corrosive and noncorrosive. Noncorrosive flux requires precleaning and is used when low acidity is required. Corrosive flux is quick and requires little precleaning, but has a higher acidity.
Preheating.
Preheating helps to accelerate the soldering process and to prevent thermal shock.
Cleaning.
Some types of flux, called "no-clean" fluxes, do not require cleaning; their residues are benign after the soldering process. Typically no-clean fluxes are especially sensitive to process conditions, which may make them undesirable in some applications. Other kinds of flux, however, require a cleaning stage, in which the PCB is washed with solvents and/or deionized water to remove flux residue.
Finish and quality.
Quality depends on proper temperatures when heating and on properly treated surfaces.
Solder types.
Different combinations of tin, lead and other metals are used to create solder. The combinations used depend on the desired properties. The most popular combinations are SAC (Tin(Sn)/Silver(Ag)/Copper(Cu)) alloys for lead-free processes and Sn63Pb37 (Sn63A) which is a eutectic alloy consisting of 63% tin and 37% lead. This latter combination is strong, has a low melting range, and melts and sets quickly (i.e., no 'plastic' range between the solid and molten states like the older 60% tin / 40% lead alloy). Higher tin compositions give the solder higher corrosion resistances, but raise the melting point. Another common composition is 11% tin, 37% lead, 42% bismuth, and 10% cadmium. This combination has a low melting point and is useful for soldering components that are sensitive to heat.
Environmental and performance requirements also factor into alloy selection. Common restrictions include restrictions on lead (Pb) when RoHS compliance is required and restrictions on pure tin (Sn) when long term reliability is a concern.
Effects of cooling rate.
It is important that the PCBs be allowed to cool at a reasonable rate. If they are cooled too fast, then the PCB can become warped and the solder can be compromised. On the other hand, if the PCB is allowed to cool too slowly, then the PCB can become brittle and some components may be damaged by heat. The PCB should be cooled by either a fine water spray or air cooled to decrease the amount of damage to the board.
Thermal profiling.
Thermal profiling is the act of measuring several points on a circuit board to determine the thermal excursion it takes through the soldering process.
In the electronics manufacturing industry, SPC (Statistical Process Control) helps determine if the process is in control, measured against the reflow parameters defined by the soldering technologies and component requirements.
Products like the Solderstar WaveShuttle and the Optiminer have been developed special fixtures which are passed through the process and can measure the temperature profile, along with contact times, wave parallelism and wave heights. These fixture combined with analysis software allows the production engineer to establish and then control the wave solder process.
Solder wave height.
The height of the solder wave is a key parameter that needs to be evaluated when setting up the wave solder process. The contact time between the solder wave and assembly being soldered is typically set to between 2 and 4 seconds. This contact time is controlled by two parameters on the machine, conveyor speed and wave height, changes to either of these parameters will result in a change in contact time. The wave height is typically controlled by increasing or decreasing the pump speed on the machine. Changes can be evaluated and checked using a tempered glass plate, if more detailed recording are required fixture are available which digitally record the contact times, height and speed. Also, some wave solder machines can give the operator a choice between a smooth laminar wave or a slightly higher-pressure 'dancer' wave.


Maurer-Union

Maurer-Union was a German car maker located in Nuremberg. From 1900-1910 Maurer-Union produced 300 to 400 cars per year. It was one of the first manufacturers that introduced continuously variable transmission using a friction drive.


Reusable packaging

Reusable packaging is manufactured of durable materials and is specifically designed for multiple trips and extended life. A "reusable package" or container is "designed for reuse without impairment of its protective function." The term returnable is sometimes used interchangeably but it can also include returning packages or components for other than reuse: recycling, disposal, incineration, etc. Typically, the materials used to make returnable packaging include steel, wood, polypropylene sheets or other plastic materials.
Reusability of packaging is an important consideration of the environmental credo of "reduce, reuse, and recycle". It is also important to the movement toward more sustainable packaging. Returnable packaging is encouraged by regulators.
Shipping containers.
For many years, several types of shipping containers have been returnable and reusable. These have made most sense when a reverse logistics system is available or can be readily developed. A return, reconditioning, and reuse system can save money on the cost per shipment and can reduce the environmental footprint of the packaging.
Manufacturing, particularly the automotive industry, has used heavy-duty returnable racks for shipping hoods, fenders, engines, dashboards, etc. from suppliers to final assembly plants. The racks are then returned for the next shipment cycle.
Bulk foods, chemicals, and pharmaceuticals are often shipped in reusable and returnable containers. These need to be carefully inspected, cleaned and sanitized as part of the reuse cycle. An effective quality management system is necessary.
Wooden pallets are often made to be expendable, for a single shipment. Others are heavy duty and intended for multiple shipments. Some are in "pallet pools" which are used, inspected, and refurbished for extended usage.
Often reusable industrial shipping containers have bar code labels or radio-frequency identification (RFID) chips to help identify and route the containers.
Use in the automotive industry.
Automotive original equipment manufacturers (OEMs) use and encourage the use of returnable packaging to move components from their vendors to their factories. The components are placed in returnable packaging and are at times and arranged in a way that facilitates movement straight to assemble lines. Such packaging replaces traditional corrugated cartons, thereby helping companies cut costs by avoiding wastage and effort required in disposing the cartons. It also helps in reducing the environmental footprint of the automotive industry.
Other advantages of using returnable packaging include avoiding damages to parts in while in transit. Parts are at times placed in specially designed receptacles for easy picking on the assembly line contributing to fewer mistakes and simpler inventory management.
A few examples of returnable packaging in automotive industry:
Consumer packaging and containers.
Several types of consumer containers have been in reuse systems. Reusable bottles for milk, soda, and beer have been part of closed-loop use-return-clean-refill-reuse cycles. Food storage containers are typically reusable. Thick plastic water bottles are promoted as an environmental improvement over thin single-use water bottles. Some plastic cups can be re-used, though most are disposable.
Home canning often uses glass mason jars which are often reused several times.
Many non-food types of containers, including reusable shopping bags, and luggage, are designed to be reused by consumers.
With any food packaging, proper cleaning and disinfecting between each use is critical to health.
In September 2019, the UK Environment, Food and Rural Affairs Committee released a report claiming that the official intervention should encourage more shops to offer refillable options instead of traditional single-use packing.
Reuse for other purposes.
Used packages are often reused for purposes other than their primary use. For example, a single-use plastic shopping bag might be reused as a bin bag, a household storage bag or a dog faeces bag. Steel drums can be reused as traffic barricades, dock flotation, and as musical instruments
Justification.
Reusable packaging often costs more initially and uses more and different materials than single-use packaging. It often requires adding complexity to the distribution system. Not all packaging justifies being returnable and reusable.
A thorough cost analysis is required. This involves all of the material, labor, transport, inspection, refurbishing, cleaning, and management costs. Often these costs may be incurred by different companies with different cost structures.
The environmental costs and benefits can also be complex. The material, energy, pollution, etc. needs to be accounted for throughout the entire system. A life cycle assessment offers a good methodology for this task.
References.
Books, general references.
Industry Associations


Original Heidelberg Platen Press

The Original Heidelberg Platen Press was a letterpress printing press manufactured by the Heidelberger Druckmaschinen company in Germany. It was often referred to as the Heidelberg Windmill, after the shape and movement of its paper feed system. When introduced, it was also called the "Super Heidelberg" or the "Super Speed".
History.
The "Original Heidelberg Platen Press" was introduced in 1914 and manufactured between 1923 and 1985.
Although the "Original Heidelberg Platen Press" is no longer being manufactured, it is still in wide use for commercial and enthusiast letterpress printing.
The company later also produced the "Original Heidelberg Cylinder Press" and today produces offset presses and printing related products.
Design and operation.
The printing press is most famous for its windmill-like automatic paper feed mechanism. There are two blades that rotate from the paper feed, where it picks up a sheet of paper; to the platen, where the printing impression is made; to the delivery rack, where the paper is released; followed by the blade pointing straight up ready to start the next cycle. There are two blades mounted on opposite sides of the rotor (when one blade is picking up the next sheet, the other blade is releasing the previously printed sheet). In addition, if the press is set for precision registration ("with gauges"), the feed arm drops the sheet onto moving gauge blocks that then pull it into precise alignment just before the press closes, then picks it back up to carry it to the delivery rack.
A clamshell-like mechanism performs the actual printing. In letterpress an impression is made on the paper by having a platen press the paper against a forme. The forme has the desired image in reverse: with raised parts where the ink is applied, and lowered parts where the ink is not applied. When a rotor has moved a page to the platen, the platen is pressed against the forme to make the impression (where ink is transferred from the form to the paper). The platen then opens up to release the printed page and allow the rollers to apply more ink to the forme. This cycle repeats for the next page.
The Original Heidelberg Platen Press also automatically inks the rollers. Ink can be added to a reservoir, or "fountain," which is then spread evenly via several rollers before reaching the rollers which make contact with the forme.
The press is driven by an electric motor that runs a flywheel. The press also contains an air pump. Air suction is used to pick up the next sheet of paper from the feed pile, so the blade can grab it as it comes around.
Models.
Two models of the press were manufactured: the Original Heidelberg 10" x 15" and the larger Original Heidelberg 13" x 18" that can print on larger sheets of paper.


Process qualification

Process qualification is the qualification of manufacturing and production processes to confirm they are able to operate at a certain standard during sustained commercial manufacturing. Data covering critical process parameters must be recorded and analyzed to ensure critical quality attributes can be guaranteed throughout production. This may include testing equipment at maximum operating capacity to show quantity demands can be met. Once all processes have been qualified the manufacturer should have a complete understanding of the process design and have a framework in place to routinely monitor operations. Only after process qualification has been completed can the manufacturing process begin production for commercial use. Equally important as qualifying processes and equipment is qualifying software and personnel. A well trained staff and accurate, thorough records helps ensure ongoing protection from process faults and quick recovery from otherwise costly process malfunctions. In many countries qualification measures are also required, especially in the pharmaceutical manufacturing field.
Process qualification should cover the following aspects of manufacturing:
Process qualification is the second stage of process validation.
A vital component of process qualification is process performance qualification protocol. PPQ protocol is essential in defining and maintaining production standards within an organization.


Mount Elliott Tool and Die

Mount Elliott Tool and Die is a Stellantis North America automotive stamping plant in Detroit, Michigan that produces Stamping Dies, Checking Fixtures, Stamping Fixtures.
It was built in 1938 by the Briggs Manufacturing Company. Chrysler purchased the plant in 1956 and it became Outer Drive Stamping plant. The facility became a tool and die plant after Vernor Tool & Die closed in 1983 and moved their operations there. The facility was then renamed Outer Drive Manufacturing Technology Center.
After the "Pilot Operations" and "Advanced Stamping Manufacturing Engineering" were moved to Chrysler Headquarters in Auburn Hills, Michigan in the 1980s, the facility was renamed "Mt. Elliott Tool and Die".
Mount Elliott currently employs around 300 people and is home to UAW Local 212. As of late 2018 Mount Elliot is currently idled.


Hardmask

A hardmask is a material used in semiconductor processing as an etch mask instead of a polymer or other organic "soft" resist material.
Hardmasks are necessary when the material being etched is itself an organic polymer. Anything used to etch this material will also etch the photoresist being used to define its patterning since that is also an organic polymer. This arises, for instance, in the patterning of low-κ dielectric insulation layers used in VLSI fabrication. Polymers tend to be etched easily by oxygen, fluorine, chlorine and other reactive gases used in plasma etching.
Use of a hardmask involves an additional deposition process, and hence additional cost. First, the hardmask material is deposited and etched into the required pattern using a standard photoresist process. Following that the underlying material can be etched through the hardmask. Finally the hardmask is removed with a further etching process.
Hardmask materials can be metal or dielectric. Silicon based masks such as silicon dioxide or silicon carbide are usually used for etching low-κ dielectrics. However, SiOCH (carbon doped hydrogenated silicon oxide), a material used to insulate copper interconnects, requires an etchant that attacks silicon compounds. For this material, metal or amorphous carbon hardmasks are used. The most common metal for hardmasks is titanium nitride, but tantalum nitride has also been used.


Reaction injection molding

Reaction injection molding (RIM) is similar to injection molding except thermosetting polymers are used, which requires a curing reaction to occur within the mold.
Common items made via RIM include automotive bumpers, air spoilers, and fenders.
Process.
The two parts of the polymer are mixed together, usually by injecting them under high pressure into an impinging mixer. Then the mixture is injected under lower pressure into a mold. The mixture is allowed to sit in the mold long enough for it to expand and cure.
If reinforcing agents are added to the mixture then the process is known as reinforced reaction injection molding (RRIM). Common reinforcing agents include glass fibers and mica. This process is usually used to produce rigid foam automotive panels.
A subset of RIM is structural reaction injection molding (SRIM), which uses fiber meshes for the reinforcing agent. The fiber mesh is first arranged in the mold and then the polymer mixture is injection molded over it.
The most common RIM processable material is polyurethane (known generally as PU-RIM), but others include polyureas, polyisocyanurates, polyesters, polyphenols, polyepoxides, and nylon 6. For polyurethane one component of the mixture is polyisocyanate and the other component is a blend of polyol, surfactant, catalyst, and blowing agent.
Advantages and disadvantages.
Reaction injection molding can produce strong, flexible, lightweight parts which can easily be painted. It also has the advantage of quick cycle times compared to typical vacuum cast materials. The bi-component mixture injected into the mold has a much lower viscosity than molten thermoplastic polymers, therefore large, light-weight, and thin-walled items can be successfully RIM processed. This thinner mixture also requires less clamping forces, which leads to smaller equipment and ultimately lower capital expenditures. Another advantage of RIM processed foam is that a high-density skin is formed with a low-density core.
The disadvantages are slow cycle times, compared to injection molding, and expensive raw materials.
Tooling.
Machined steel or aluminum; cast aluminum; silicone rubber; epoxy resin; nickel. The machines can be large or small depending on the size of part required.


Riveting machine

A riveting machine is used to automatically set (squeeze) rivets in order to join materials together. The riveting machine offers greater consistency, productivity, and lower cost when compared to manual riveting.
Types.
Automatic feed riveting machines include a hopper and feed track which automatically delivers and presents the rivet to the setting tools which overcomes the need for the operator to position the rivet. The downward force required to deform the rivet with an automatic riveting machine is created by a motor and flywheel combination, pneumatic cylinder, or hydraulic cylinder. Manual feed riveting machines usually have a mechanical lever to deliver the setting force from a foot pedal or hand lever.
Riveting machines can be sub-divided into two broad groups — impact riveting machines and orbital (or radial) riveting machines.
Impact riveting.
Impact riveting machines set the rivet by driving the rivet downwards, through the materials to be joined and on into a forming tool (known as a rollset). This action causes the end of the rivet to roll over in the rollset which causes the end of the rivet to flare out and thus join the materials together. Impact riveting machines are very fast and a cycle time of 0.5 seconds is typical.
Orbital riveting.
Orbital riveting machines have a spinning forming tool (known as a peen) which is gradually lowered into the rivet which spreads the material of the rivet into a desired shape depending upon the design of the tool. Orbital forming machines offer the user more control over the riveting cycle but the trade off is in cycle time which can be 2 or 3 seconds.
There are different types of riveting machines. Each type of machine has unique features and benefits. The orbital riveting process is different from impact riveting and spiralform riveting. Orbital riveting requires less downward force than impact or spiral riveting. Also, orbital riveting tooling typically lasts longer.
Orbital riveting machines are used in a wide range of applications including brake linings for commercial vehicles, aircraft, and locomotives, textile and leather goods, metal brackets, window and door furniture, latches and even mobile phones. Many materials can be riveted together using orbital riveting machines including delicate and brittle materials, and sensitive electrical or electronic components.
The orbital riveting process uses a forming tool mounted at a 3 or 6° angle. The forming tool contacts the material and then presses it while rotating until the final form is achieved. The final form often has height and/or diameter specifications.
Pneumatic orbital riveting machines typically provide downward force in the range. Hydraulic orbital riveting machines typically provide downward force in the range.
Radial (Spiralform) riveting.
Radial riveting is subtly different from orbital forming. In most cases however, where high-quality joints are demanded, the radial riveting technology is the appropriate procedure due to the low cyle time, the little force needed and the high quality results obtained.
The riveting peen describes a rose-petal path. The rivet is deformed in three directions. Radially outwards, radially inwards and overlying also tangentially.
Excellent surface structure of the closing head: With the Radial riveting process, the tool itself does not rotate. The friction between tool and work-piece is thus at a minimum. The result is an excellent surface structure.
Low workpiece loading: Even bakelite or ceramic parts can be riveted. Lateral forces are negligible. Clamping is usually unnecessary.
Rollerform riveting.
Rollerforming is a subset of orbital forming. Rollerforming uses the same powerhead as orbital forming but instead of a peen has multiple wheels that circle the workpiece and combine two similar or non-similar materials together with a seamless and smooth gentle bonding via downward pressure as the rollers move downward or inward on the piece.
Automatic drilling and riveting machine.
These machines take the automation one step farther by clamping the material and drilling or countersinking the hole in addition to riveting. They are commonly used in the aerospace industry because of the large number of holes and rivets required to assemble the aircraft skin.
Applications.
Riveting machines are used in a wide range of applications including brake linings for commercial vehicles, aircraft, and locomotives, textile and leather goods, metal brackets, window and door furniture, latches and even mobile phones. Many materials can be riveted together using riveting machines including delicate and brittle materials, and sensitive electrical or electronic components.


Threaded insert

A threaded insert, also known as a threaded bushing, is a fastener element that is inserted into an object to add a threaded hole. They may be used to repair a stripped threaded hole, provide a durable threaded hole in a soft material, place a thread on a material too thin to accept it, mold or cast threads into a work piece thereby eliminating a machining operation, or simplify changeover from unified to metric threads or vice versa.
Types.
Thread inserts come in many varieties, depending on the application. Threaded inserts for plastics are used in plastic materials and applied with thermal insertion or ultrasonic welding machines.
Manufacturers of ready-to-assemble furniture often ship the parts with threaded inserts and other kinds of knock-down fasteners pre-installed.
People who use sheet metal or sandwich panel or honeycomb sandwich-structured composite often install threaded inserts to spread shear, tension, and torque loads over a larger area of the material.
Captive nut.
Captive nuts come in two basic styles. One type, the cage nut or clip-on nut is a conventional nut held captive by a sheet metal carrier that clips onto the part to be connected. These are generally used to attach screws to sheet metal parts too thin to be threaded, and
they can generally be attached, removed and reused with simple hand tools.
The second type of captive nut is a threaded insert. These are either pressed into holes in the material to be joined or moulded in. In either case, part of the insert is generally knurled to get a good grip on the material supporting the insert. One variant, the swage nut, has a knurled portion that swages the sides of a soft metal hole to more tightly grip the nut. Press fit and swaged captive nuts are used in panels that are too thin to be threaded or in soft materials that are too weak to be threaded. They are installed by pressing them in with an arbor press.
Threaded inserts are commonly used in plastic casings, housing, and parts to create a metal thread (typically: brass or stainless steel) to allow for screws to be used in the assembly of many consumer electronics and consumer products. These may be cast in place in injection molded parts or they may be added by thermal insertion. In the latter, the insert is heated and then pressed into a hollow in the plastic part. The heat causes local melting in the plastic. Ultrasonic Insertion is the process used to apply vibration and pressure to install the threaded insert into a molded hollow boss (hole) of a plastic part. The ultrasonic vibrations melt the thermoplastic material where the metal insert is in contact, and pressure is applied to press it into position. The material typically reforms around the knurled body of the threaded insert to ensure a good retention.
Externally-threaded inserts.
Externally threaded inserts have threads on the outside and inside of the insert. The insert is threaded into a pre-tapped hole, or some inserts tap their own threads in a drilled or molded hole. It is then anchored by various means, such as a nylon locking element. Inserts that are anchored via Loctite are more commonly known by the trademarked name "E-Z Lok". A thin walled solid bushing insert by the trademarked name "TIME-SERT" is locked in by rolling the bottom few internal thread into the base material with a special install driver which will permanently lock the insert in place. Key locking inserts, more commonly known by the trademarked name "Keenserts", use keys that are hammered into grooves through the threads, permanently locking the insert. Inserts that are self-tapping and lock via friction are more commonly known by the trademarked names Tap-lok or Speedserts.
Helical insert.
A helical insert (also called a screw thread insert (STI), although most users call them all by the prominent brand name, Heli-Coil® or Recoil®) is an insert made of diamond shaped stainless steel, or phosphor bronze, coiled wire. The
coil of wire screws into a threaded hole, where it forms a smaller diameter internal thread for a screw or stud. These inserts provide a convenient means of repairing stripped-out threads. These inserts are commonly sold as kits with matched tap, coil, and insert tool.
In soft materials, they are used to provide stronger threads than can be obtained by direct tapping of the base materials, e.g. aluminium, zinc die castings, wood, magnesium, plastic.
An example application is engine repair after unintentionally destroying the threads in the socket for a spark plug by over-torquing or by cross-threading.
Mold-in inserts.
Mold-in inserts are internally threaded and have a specially shaped outer diameter to anchor the insert in plastic. The insert is placed in the mold of an injection molded part beforehand. The mold is then closed and filled with the plastic filling in around the insert. These inserts can also be heated and pressed into pre-made thermoplastics.
For softer more pliable plastics, hexagonal or square inserts with deep and wide grooves allow the plastic to flow and adhere. The process allows large product manufacture i.e. fuel tanks, boats etc., so the torque inserts may be of large thread sizes.
Press fit inserts.
Press fit inserts are internally threaded and have a knurled outer diameter. They are pressed into a plain hole with an arbor press.
Potted inserts.
An insert that is potted-in refers to the application of epoxy to fix it to a panel, such as a honeycomb sandwich panel, which are often used in commercial aircraft.
Strength factor for threaded inserts.
"Resistance" is the key strength factor in case of inserts, pull-out & torque-out are the two parameters to judge inserts.
Knurling.
Knurling is the metalworking which is done on the outer side of the component. In case of Brass Insert, knurling plays an important role in increasing pull-out & torque-out resistance. Types of knurling and its benefit are as follows:
Installation methods.
For industrial purposes, following installation methods are the standards:


Machine tending

Machine tending refers to the automated operation of industrial machine tools in a manufacturing plant, primarily using robot automation systems. While loading and unloading is the primary function of machine tending systems, often the robot performs other valuable functions within the automation system such as part inspection, blow off, wash, deburring, sorting, packaging and gauging.
Benefits of machine tending systems include:
Because of the sophistication, functionality, and costs associated with machine tending systems, most manufacturers require a capital approval process prior to investing in these systems where executive management must approve the purchase. Typically, an ROI (return on investment) is calculated to justify the purchase.


Automated storage and retrieval system

An automated storage and retrieval system (ASRS or AS/RS) consists of a variety of computer-controlled systems for automatically placing and retrieving loads from defined storage locations. Automated storage and retrieval systems (AS/RS) are typically used in applications where:
An AS/RS can be used with standard loads as well as nonstandard loads, meaning that each standard load can fit in a uniformly-sized volume; for example, the film canisters in the image of the Defense Visual Information Center are each stored as part of the contents of the uniformly sized metal boxes, which are shown in the image. Standard loads simplify the handling of a request of an item. In addition, audits of the accuracy of the inventory of contents can be restricted to the contents of an individual metal box, rather than undergoing a top-to-bottom search of the entire facility, for a single item.
They can also be used in self storage places.
Overview.
AS/RS systems are designed for automated storage and retrieval of parts and items in manufacturing, distribution, retail, wholesale and institutions. They first originated in the 1960s, initially focusing on heavy pallet loads but with the evolution of the technology the handled loads have become smaller. The systems operate under computerized control, maintaining an inventory of stored items. Retrieval of items is accomplished by specifying the item type and quantity to be retrieved. The computer determines where in the storage area the item can be retrieved from and schedules the retrieval. It directs the proper automated storage and retrieval machine (SRM) to the location where the item is stored and directs the machine to deposit the item at a location where it is to be picked up. A system of conveyors and or automated guided vehicles is sometimes part of the AS/RS system. These take loads into and out of the storage area and move them to the manufacturing floor or loading docks. To store items, the pallet or tray is placed at an input station for the system, the information for inventory is entered into a computer terminal and the AS/RS system moves the load to the storage area, determines a suitable location for the item, and stores the load. As items are stored into or retrieved from the racks, the computer updates its inventory accordingly.
The benefits of an AS/RS system include reduced labor for transporting items into and out of inventory, reduced
inventory levels, more accurate tracking of inventory, and space savings. Items are often stored more densely than in systems where items are stored and retrieved manually.
Within the storage, items can be placed on trays or hang from bars, which are attached to chains/drives in order to move up and down. The equipment required for an AS/RS include a storage & retrieval machine (SRM) that is used for rapid storage and retrieval of material. SRMs are used to move loads vertically or horizontally, and can also move laterally to place objects in the correct storage location.
The trend towards Just In Time production often requires sub-pallet level availability of production inputs, and AS/RS is a much faster way of organizing the storage of smaller items next to production lines.
The Material Handling Institute of America (MHIA), the non-profit trade association for the material handling world, and its members have categorised AS/RS into two primary segments: Fixed Aisle and Carousels/Vertical Lift Modules (VLMs). Both sets of technologies provide automated storage and retrieval for parts and items, but use different technologies. Each technology has its unique set of benefits and disadvantages. Fixed Aisle systems are characteristically larger systems whereas carousels and Vertical Lift Modules are used individually or grouped, but in small to medium-sized applications.
A fixed-aisle AS/R machine (stacker crane) is one of two main designs: single-masted or double masted. Most are supported on a track and ceiling guided at the top by guide rails or channels to ensure accurate vertical alignment, although some are suspended from the ceiling. The 'shuttles' that make up the system travel between fixed storage shelves to deposit or retrieve a requested load (ranging from a single book in a library system to a several ton pallet of goods in a warehouse system). The entire unit moves horizontally within an aisle, while the shuttles are able to elevate up to the necessary height to reach the load, and can extend and retract to store or retrieve loads that are several positions deep in the shelving. A semi-automated system can be achieved by utilizing only specialized shuttles within an existing rack system.
Another AS/RS technology is known as shuttle technology. In this technology the horizontal movement is made by independent shuttles each operating on one level of the rack while a lift at a fixed position within the rack is responsible for the vertical movement. By using two separate machines for these two axes the shuttle technology is able to provide higher throughput rates than stacker cranes.
Storage and Retrieval Machines pick up or drop off loads to the rest of the supporting transportation system at specific stations, where inbound and outbound loads are precisely positioned for proper handling.
In addition, there are several types of Automated Storage & Retrieval Systems (AS/RS) devices called Unit-load AS/RS, Mini-load AS/RS, Mid-Load AS/RS, Vertical Lift Modules (VLMs), Horizontal Carousels and Vertical Carousels. These systems are used either as stand-alone units or in integrated workstations called pods or systems. These units are usually integrated with various types of pick to light systems and use either a microprocessor controller for basic usage or inventory management software. These systems are ideal for increasing space utilization up to 90%, productivity levels by 90%, accuracy to 99.9%+ levels and throughput up to 750 lines per hour/per operator or more depending on the configuration of the system.
Advantages.
An effective automated storage and retrieval system provides several benefits for supply chain management
Vertical lift module.
Vertical lift modules (VLMs) can be built to a height to match the available overhead space in a facility. Multiple units can be placed in 'pods' whereby an operator can retrieve items from one unit while the other units are moving. Variants include width, height, load, speed and a control system.
The VLM is a board controlled automated vertical lift module. Inventory within the VLM is stored on front and rear tray locations or rails. When a tray is requested, either by entering a tray number in the built-in control pad or by requesting a part through software, an extractor travels vertically between the two columns of trays and pulls the requested tray from its location and brings it to an access point. The operator then picks or replenishes stock and the tray is returned to its home upon confirmation.
VLM systems are sold in numerous configurations, which could be applied in different industries, logistics, as well as office settings. The VLM systems could be customized to fully utilize the height of the facility, even through multiple floors. With the capability of multiple access openings on different floors, a VLM system is able to provide an innovative storage and retrieval solution. The rapid movement of the extractor, as well as inventory management software, can dramatically increase the efficiency of the picking process. This occurs by simultaneously retrieving and storing trays in multiple units. Unlike large AS/RS systems, which require a complete overhaul of the warehouse or production line, the vertical lift modules are modularized, which can be easily integrated into the existing system, or to be rolled out in gradually over different phases.
Most common applications include: MRO, order picking, consolidation, kitting, parts handling, buffering, inventory storage, WIP, buffer storage, and many more.
VLMs provide floor space savings, increased labor productivity and picking accuracy, improved worker ergonomics, and controlled process.
Most VLMs offer dynamic space storage which measures the tray every time it is returned to the unit to optimize space, safety features and some offer tilt-tray delivery for increased ergonomic accessibility, and laser pointers which indicate the exact item to be picked on each tray.
Horizontal carousels.
A horizontal carousel is a series of bins which revolve on an oval track. Every bin has shelves which are adjustable to and can be configured for a myriad of standard and special applications. An operator simply inputs a bin number, part number or cell location and the carousel will rotate via the shortest path. Multiple horizontal carousels integrated with pick to light technology and inventory management software (a pod of carousels) are used for order fulfillment.
A wave of orders is sent to the pod. A group of orders is selected to create a batch. The operator simply follows the lights and pick round-robin from the carousels and place items in a batch station behind them. Each carousel pre-positions and rotates when picked. By applying the "product to person" principle, operators do not have to move from their position to prepare the order.
When the batch is complete, a new batch is inducted and the process repeated until the wave is complete. Horizontal carousels can save up to 75% of floorspace, increase productivity by 2/3, accuracy levels to 99.9+% levels and throughput up to 750 lines per hour/operator.
Horizontal carousel systems generally outperform robotic systems for a fraction of the cost. Horizontal carousels are the most cost-effective AS/RS system available.
Robotic Inserter/Extractor devices can also be used for horizontal carousels. The robotic device is positioned in the front or rear of up to three horizontal carousels tiered high. The robot grabs the tote required in the order and often replenishes at the same time to speed up throughput. The tote(s) are then delivered to a conveyor, which routes it to a work station for picking or replenishing. Up to eight transactions per minute per unit can be done. Totes or containers up to 36" x 36" x 36" can be used in a system.
On a simplistic level, horizontal carousels are also often used as "rotating shelving." With simple "fetch" command, items are brought to the operator and otherwise wasted space is eliminated.
AS/RS Applications: Most applications of AS/RS technology have been associated with warehousing and distribution operations. An AS/RS can also be used to store raw materials and work in process in manufacturing. Three application areas can be distinguished for AS/RS: (1) Unit load storage and handling, (2) Order picking, and (3) Work in process storage. Unit load storage and retrieval applications are represented by unit load AS/RS and deep-lane storage systems. These kinds of applications are commonly found in warehousing for finishing goods in a distribution center, rarely in manufacturing. Deep-lane systems are used in the food industry. As described above, order picking involves retrieving materials in less than full unit load quantities. Minilpass, man-on board, and items retrieval systems are used for this second application area.
Work in process storage is a more recent application of automated storage technology. While it is desirable to minimize the amount of work in process, WIP is unavoidable and must be effectively managed. Automated storage systems, either automated storage/retrieval systems or carousel systems, represent an efficient way to store materials between processing steps, particularly in batch and job shop production. In high production, work in process is often carried between operations by conveyor system, which this serve both storage and transport functions.
Installed applications.
Installed applications of this technology can be wide-ranging. In some libraries, such as at University of Nevada, Reno library, such a system is employed to retrieve books. Still others in use involve retrieval of bicycles from a bicycle tree, as in the case of systems in Japan.
Institutions using automated storage and retrieval systems.
Some examples of academic institutions using automated storage and retrieval systems are;
Man-aboard systems.
A man-aboard system can provide significant floorspace savings over manual or forklift operations but is not truly an AS/RS, as the operation is still manual. Storage system heights are not limited by the reach height of the order picker, as the picker rides along on the platform as it is moved vertically or horizontally to the various storage locations. Shelves or storage cabinets can be stacked as high as floor loading, weight capacity, throughput requirements, and/or ceiling heights will permit. Man-aboard storage and retrieval systems are far and away the most expensive picker-to-stock equipment alternative but are less expensive than a fully automated system. Aisle-captive storage/retrieval machines reaching heights up to cost around $125,000. Hence, there must be enough storage density and/or productivity improvement over cart and tote picking to justify the investment. Also, because vertical travel is slow compared to horizontal travel, typical picking rates in man-aboard operations range between 40 and 250 lines per person-hour. The range is large because there is a wide variety of operating schemes for man-aboard systems. Man-aboard systems are typically appropriate for slow-moving items where space is fairly expensive.


Electrochemical grinding

Electrochemical grinding is a process that removes electrically conductive material by grinding with a negatively charged abrasive grinding wheel, an electrolyte fluid, and a positively charged workpiece. Materials removed from the workpiece stay in the electrolyte fluid. Electrochemical grinding is similar to electrochemical machining but uses a wheel instead of a tool shaped like the contour of the workpiece.
Process.
The electrochemical grinding process combines traditional electrochemical machining and grinding processes to remove material from a workpiece. A grinding wheel is used as a cutting tool as a cathode and the workpiece is an anode. During the process, electrolytic fluid, typically sodium nitrate, is pumped into the space between the workpiece and the grinding wheel. Other electrolytes used include sodium hydroxide, sodium carbonate, and sodium chloride. This electrolytic fluid will cause electrochemical reactions to occur at the workpiece surface which oxidize the surface, thereby removing material. As a consequence of the oxidation which occurs, layers of oxide films will form on the workpiece surface, and these need to be removed by the grinding wheel. A couple schematics of the process are provided below.
Abrasive materials, either diamond or aluminum oxide, are bonded to the grinding wheel, which allows the wheel to remove the oxide layers on the workpiece surface by abrasive action. Appropriate materials used for electrolyte fluid and the grinding wheel abrasives are summarized in the table below.
Most material removal is by the electrochemical reactions which occur at the workpiece surface. Five percent or less of the material removal is carried out by the abrasive action of the grinding wheel. The fact that most material is not removed by abrasive action helps increase the life of the grinding wheel; that is, the tool will take a long time to wear down. The electrolytic fluid serves another useful purpose - it flushes out leftover material in between the grinding wheel and workpiece. The abrasive particles bonded to the grinding wheel will help to electrically insulate the space between the grinding wheel and workpiece. An equation giving the material removal rate for an electrochemical grinding process is provided in and is stated here as:
MRR = GI/ρF
where ρ is the workpiece density, G is the total mass of the workpiece, I is the current supplied, MRR is the material removal rate, and F is Faraday's constant.
Some of the main factors which govern the performance of an electrochemical grinding process include current supplied, rotation speed of the grinding wheel, the workpiece feed rate, the type of electrolyte used, electrolyte feed rate, and the workpiece's chemical properties. By changing these parameters, one can alter the material removal rate. Increasing the supplied current, rotation speed of the wheel, electrolyte feed rate, or the workpiece feed rate will lead to an increase in material removal rate (MRR), while decreasing these properties will do the opposite. If the workpiece is more reactive to the electrolyte used, then the material removal rate will increase. The grinding wheel is usually rotated with a surface speed of 1200–2000 m/min and supplied currents are around 1000A.
The accuracy of parts made by electrochemical grinding is strongly dictated by the chemical properties of the workpiece and electrolytic fluid used. If the workpiece is very reactive to the electrolyte, and if too much electrolyte is pumped into the space between the grinding wheel and workpiece, it may be difficult to control the material removal, which can lead to loss of accuracy. Also, accuracy may be reduced if the workpiece feed rate is too high.
The wheels are metal disks with abrasive particles embedded. Copper, brass, and nickel are the most commonly used materials; aluminum oxide is typically used as an abrasive when grinding steel. A thin layer of diamond particles will be used when grinding carbides or steels harder than 65 Rc.
An electrolytic spindle with carbon brushes, acting as a commutator, holds the wheel. The spindle receives a negative charge from the DC power supply, which gives the workpiece a positive charge. The electrolytic fluid is applied where the work contacts the tool by a nozzle similar to that which supplies coolant in conventional grinding. The fluid works with the wheel to form electrochemical cells that oxidize the surface of the workpiece. As the wheel carries away the oxide, fresh metal is exposed. Removing the oxidized fluid may only require a pressure of 20 psi or less, causing much less distortion than mechanical grinding. The wheel is subject to little wear, reducing the need for truing and dressing.
Applications.
Electrochemical grinding is often used for hard materials where conventional machining is difficult and time-consuming, such as stainless steel and some exotic metals. For materials with hardness greater than 65 HRC, ECG can have a material removal rate 10 times that of conventional machining. Because ECG involves little abrasion, it is often used for processes where the surface of the part is needs to be free of burrs, scratches, and residual stresses. Because of these properties, electrochemical grinding has a number of useful applications.
Advantages and disadvantages.
One of the key advantages of electrochemical grinding is the minimal wear that the grinding wheel tool experiences. This is because the majority of the material is removed by the electrochemical reaction that occurs between the cathode and anode. The only time that abrasive grinding actually occurs is in removing the film that develops on the surface of the workpiece. Another advantage of electrochemical grinding is that it can be used to machine hard materials. Hard materials pose a difficulty to other types of machining due to the tool wear that is associated with machining hard materials. It may come as a bit of a surprise that electrochemical grinding can remove material from a hard surface and experience minimal wear. Because most material is removed through electrochemical reactions, the workpiece does not experience heat damage like it would in a conventional grinding process.
Electrochemical grinding also has a few disadvantages as well. The system consists of the anode workpiece and the cathode grinding wheel. In order to create those conditions both the workpiece and the grinding wheel must be conductive. This limits the types of workpiece materials that are suitable for electrochemical grinding. Another disadvantage of electrochemical grinding is that it is only applicable to surface grinding. It is not possible to apply electrochemical grinding to workpieces that have cavities, due to the grinding wheels inability to remove the film deposit with in the cavity. One other disadvantage is the electrolytic fluid can cause corrosion at the workpiece and grinding wheel surfaces. Lastly, electrochemical grinding is more complicated than traditional machining methods. This will require more experienced personnel to operate the machinery, which will lead to higher production cost. Another disadvantage is that chemical used during grinding process need to be properly disposed of depending on the environmental regulation.


Weld line

In manufacturing, the Weld line or Knit line or Meld line is the line where two flow fronts meet when there is the inability of two or more flow fronts to "knit" together, or "weld", during the molding process. These lines usually occur around holes or obstructions and cause locally weak areas in the molded part. Knit lines are considered molding defects, and occur when the mold or/and material temperatures are set too low: thus the materials will be cold when they meet, so that they do not bond perfectly. This can cause a weak area in the part which can cause breakage when the part is under stress. Weld lines therefore occur during machine start-up, when equilibrium conditions have not been met. Mouldings made in this setting-up period must be rejected.
There are many Computer Aided Engineering tools that are available that can predict where these areas could occur, but a skilled designer will be able to predict where such defects can be found by examining the tool or product.
Weld lines are not found in other manufacturing methods such as Rotational moulding, but can exist in extrusion, especially where there are internal metal supports for a die. The defects are then known as spider lines.
Causes.
Weld lines can be caused by several different problems: