Wafer testing

Wafer testing is a step performed during semiconductor device fabrication after BEOL process is finished. During this step, performed before a wafer is sent to die preparation, all individual integrated circuits that are present on the wafer are tested for functional defects by applying special test patterns to them. The wafer testing is performed by a piece of test equipment called a wafer prober. The process of wafer testing can be referred to in several ways: Wafer Final Test (WFT), Electronic Die Sort (EDS) and Circuit Probe (CP) are probably the most common.
Wafer prober.
A wafer prober is a machine used for integrated circuits verification against designed functionality. It's either manual or automatic test equipment. For electrical testing a set of microscopic contacts or probes called a probe card are held in place whilst the wafer, vacuum-mounted on a wafer chuck, is moved into electrical contact. When a die (or array of dice) have been electrically tested the prober moves the wafer to the next die (or array) and the next test can start. The wafer prober is usually responsible for loading and unloading the wafers from their carrier (or cassette) and is equipped with automatic pattern recognition optics capable of aligning the wafer with sufficient accuracy to ensure accurate registration between the contact pads on the wafer and the tips of the probes.
For today's multi-die packages such as stacked chip-scale package (SCSP) or system in package (SiP) – the development of non-contact (RF) probes for identification of known tested die (KTD) and known good die (KGD) are critical to increasing overall system yield.
The wafer prober also exercises any test circuitry on the wafer scribe lines.
Some companies get most of their information about device performance from these scribe line test structures.
When all test patterns pass for a specific die, its position is remembered for later use during IC packaging. Sometimes a die has internal spare resources available for repairing (i.e. flash memory IC); if it does not pass some test patterns these spare resources can be used. If redundancy of failed die is not possible the die is considered faulty and is discarded. Non-passing circuits are typically marked with a small dot of ink in the middle of the die, or the information of passing/non-passing is stored in a file, named a wafermap. This map categorizes the passing and non-passing dies by making use of bins. A bin is then defined as a good or bad die. This wafermap is then sent to the die attachment process which then only picks up the passing circuits by selecting the bin number of good dies. The process where no ink dot is used to mark the bad dies is named substrate mapping. When ink dots are used, vision systems on subsequent die handling equipment can disqualify the die by recognizing the ink dot.
In some very specific cases, a die that passes some but not all test patterns can still be used as a product, typically with limited functionality. The most common example of this is a microprocessor for which only one part of the on-die cache memory is functional. In this case, the processor can sometimes still be sold as a lower cost part with a smaller amount of memory and thus lower performance. Additionally when bad dies have been identified, the die from the bad bin can be used by production personnel for assembly line setup.
The contents of all test patterns and the sequence by which they are applied to an integrated circuit are called the test program.
After IC packaging, a packaged chip will be tested again during the IC testing phase, usually with the same or very similar test patterns. For this reason, it may be thought that wafer testing is an unnecessary, redundant step. In reality this is not usually the case, since the removal of defective dies saves the considerable cost of packaging faulty devices. However, when the production yield is so high that wafer testing is more expensive than the packaging cost of defect devices, the wafer testing step can be skipped altogether and dies will undergo blind assembly.


Original equipment manufacturer

An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional organizations such as SAE International, ISO, and others.
However, the term is also used in several other ways, which causes ambiguity. It sometimes means the maker of a system that includes other companies' subsystems, an end-product producer, an automotive part that is manufactured by the same company that produced the original part used in the automobile's assembly, or a value-added reseller.
Automotive parts.
When referring to auto parts, OEM typically refers to the manufacturer of the original equipment, that is, the parts which are then subsequently assembled and installed during the construction of a new vehicle. In contrast, aftermarket parts are those made by companies other than the OEM, which might be installed as replacements or enhancements after the car comes out of the factory. For example, if Ford used Autolite spark plugs, Exide batteries, Bosch fuel injectors, and Ford's own engine blocks and heads when building a car, then car restorers and collectors consider those to be the OEM parts. Other-brand parts would be considered aftermarket, such as Champion spark plugs, DieHard batteries, Kinsler fuel injectors, and BMP engine blocks and heads. Many auto parts manufacturers sell parts through multiple channels, for example to car makers for installation during new-vehicle construction, to car makers for resale as automaker-branded replacement parts, and through general merchandising supply chains. Any given brand of part can be OEM on some vehicle models and aftermarket on others.
Computer software.
Microsoft is a popular example of a company that issues its Windows operating systems for use by OEM computer manufacturers via the bundling of Microsoft Windows. OEM product keys are priced lower than their retail counterparts, especially as they are purchased in bulk quantities, although they use the same software as retail versions of Windows. They are primarily for PC manufacturer OEMs and system builders, and as such are typically sold in volume licensing deals to a variety of manufacturers (Dell, HP, ASUS, Acer, Lenovo, Wistron, Inventec, Supermicro, Compal Electronics, Quanta Computer, Foxconn, Pegatron, Jabil, Flex, etc.). These OEMs commonly use a procedure known as System Locked Pre-installation, which pre-activates Windows on PCs that are to be sold via mass distribution. These OEMs also commonly bundle software that is not installed on stock Windows on the images of Windows that will be deployed with their PCs (appropriate hardware drivers, anti-malware and maintenance software, various apps, etc.).
Individuals may also purchase OEM "system-builder" licenses for personal use (to include virtual hardware), or for sale/resale on PCs which they build. Per Microsoft’s EULA regarding PC manufacturers and system-builder OEM licenses, the product key is tied to the PC motherboard which it is initially installed on, and there is "typically" no transferring the key between PCs afterward. This is in contrast to retail keys, which may be transferred, provided they are only activated on one PC at a time. A significant hardware change will trigger a reactivation notice, just as with retail.
Direct OEMs are officially held liable for things such as installation/recovery media, and as such were commonly provided until the late-2000s. These were phased out in favor of recovery partitions located on the primary storage drive of the PC (and available for order from the manufacturer upon request) for the user to repair or restore their systems to the factory state. This not only cut down on costs, but was also a consequence of the gradual obsolescence and phasing out of optical media from 2010 onward. System builders also have a different requirement regarding installation media from Direct OEMs.
While a clean retail media of Windows can be installed and activated on these devices with OEM keys (most commonly using the SLP key that's embedded in to the system firmware already), actual OEM recovery media that was created by the PC manufacturer (not system-builder, nor retail Windows versions) typically only works on the PC model line that was designed for it. For example, a recovery disc/USB for a Toshiba Satellite P50-B will only work on that model, and not a Satellite S55T.
Economies of scale.
OEMs rely on their ability to drive down the cost of production through economies of scale. Using an OEM also allows the purchasing company to obtain needed components or products without owning and operating a factory.
Misuse.
Some companies mistakenly use the title OEM when referring to Custom Machine Builders, Systems Integrators, and other companies that design and build custom factory automation. Two such companies include Keyence and Omron.


Folding carton

The folding carton created the packaging industry as it is known today, beginning in the late 19th century. The process involves folding carton made of paperboard that is printed, laminated, cut, then folded and glued. The cartons are shipped flat to a packager, which has its own machinery to fold the carton into its final shape as a container for a product. An example of such a carton is a cereal box.
Some styles of folding cartons can be made of E-flute or micro-flute corrugated fiberboard.
Invention and development.
In the 1840s, cartons were made by hand and held together with tacks and string, and used only for expensive items (such as jewellery). Although Charles Henry Foyle is described by some as the "inventor" of the paper carton, mass production of the cartons was invented, partly by accident, at the Robert Gair Company in Brooklyn, New York. Machinery at the end of the press had been set up carelessly by a pressman, and machinery cut through the material. This ruined the press but gave them an idea: printing and cutting could be done with one machine. Previously, cutting of printed cardboard had been done manually. From the mistake in 1879, Gair developed a process for mass production of boxes. In 1897, the National Biscuit Company (Nabisco) became the first large company to adopt the new cartons, for Uneeda Biscuits. Other manufacturers soon followed. With inexpensive packaging now even common items could be placed in a showy carton and each carton became its own advertisement. The product was also protected, and the contents had a longer shelf life. This trend was to continue with force, through the 20th century. This could be seen as a contributing factor in the so-called 'throwaway' culture of America. The environmental impact of product packaging has gained attention from consumers and businesses alike, and this awareness has created a steady trend since the mid to late 1990s, on the part of manufacturers, to use recycled material and/or reduce overall materials usage.
Product characteristics.
Folding cartons are now a $110 billion industry. Typically, cylinder board made from pulp from reprocessed scrap paper is used for most packages. Cartons for food are made from a higher grade and lighter solid sulfate board with plastic coating. Because of the limitations of cutting machinery, the thickness of the board is limited to 0.81 mm (0.032 in), and folding cartons are generally limited to holding a few pounds or kilograms of material.
Folding cartons are frequently tall and wide but very thin. For example a typical breakfast cereal box has a poor material to volume ratio and is very inefficient; it is wasteful and can be considered overpackaging. Package designers are aware of this opportunity to save packaging costs, materials, and waste but marketing and merchandising people want the “billboard” style package for advertising and graphics. An optimized folding carton would use much less paperboard for the same volume of cereal, but with reduced room for graphics.
Opening.
Opening a carton can be accomplished by opening an access flap, cutting, use of tear tapes or perforations.


Measurement-assisted assembly

Measurement-assisted assembly (MAA) is any method of assembly in which measurements are used to guide assembly processes. Such processes include:
Measurement-assisted assembly is typically used for large structures such as aircraft and steel fabrications. It can be used to improve production rates, reduce reworking and increase flexibility for processes where manual reworking during assembly is required to maintain assembly form and component interface conditions. This type of approach generally offers no advantages where part-to-part interchangeability can already be achieved.


Just in sequence

Just in sequence (JIS) is an inventory strategy that matches just in time (JIT) and complete fit in sequence with variation of assembly line production. Components and parts arrive at a production line right in time as scheduled before they get assembled. Feedback from the manufacturing line is used to coordinate transport to and from the process area. When implemented successfully, JIS improves a company's return on assets (ROA), without loss in flexibility, quality or overall efficiency. JIS is mainly implemented with car manufacture.
JIS is sometimes called In-Line Vehicle Sequencing (ILVS).
Just in sequence is just in time.
Just in sequence (JIS) is just one specialised strategy to achieve just in time (JIT). The process concept of JIT sees buffers at the production line as waste in capital bound. The aim is to eliminate buffers as much as possible at the expense of stability when disturbances arise. Just In Sequence is one of the most extreme applications of the concept, where components arrive Just In Time and sequenced for consumption.
The sequencing allows companies to eliminate supply buffers as soon as the quantity in component part buffers necessary is reduced to a minimum. If not sequencing according to scheduled variety of production, all required components must be stocked in buffers. For flexible production lines, such as a modern automotive assembly line, the variety is an option to produce directly on customer orders. As soon as the next order arrives at the work center, the scheduler distributes the supply orders inline with the production sequence of the final production line.
Displacement of buffers upwards to suppliers.
However, with JIS the buffer quantities are displaced upward in material flow to the components suppliers. It is a misinterpretation of JIS to assume that all buffers will be eliminated. Hence just the cost for buffer inventory becomes re-allocated to the producers of the supplies. Sequencing eliminates buffers in the final assembly line by consolidating all similar components into distributed and sequenced buffers, which partly reside on the paths of transport to final assembly. This strategy thus reduces the line-side inventory buffer. However, the effect is worse when the sequence does not get correctly scheduled upwards or when the transport line gets congested.
Introduction of JIS concepts.
Just In Sequence processes are typically implemented only after the company has achieved a high degree of competency on Just In Time processes. The first step for the organization is to implement JIT processes to synchronize all manufacturing and material departments inside the plant and to collaborate with suppliers, customers, and sub-contractors to reduce inventory buffers to within a few hours. This process typically uncovers deep manufacturing and logistic issues that are not easy to overcome (see JIT Implementation for more details). The manufacturing company can only benefit from sequencing items once these problems have been resolved successfully and components are delivered Just In Time.
Sequencing can be implemented in a Just In Time supply operation at many levels, bringing ever-higher inventory reduction and financial benefits:
Implementing JIS concepts.
Just In Sequence implementations introduce a number of new process requirements on top of Just In Time practices. A production sequence or final assembly sequence must be shared upwards to suppliers and sub-contractors. Feedback to customers must be organized according to the scheduled output to earn all positive financial effects. For these and other reasons, the actual production sequence must be "broadcast" out to all relevant parties once it is firm. This "broadcast" can be done over the phone, paper, email, or other automated IT system. UN/EDIFACT supports an EDI message standard called DELJIT as one standardized way to communicate this information.
Once the sequence is broadcast, each party must immediately take action to deliver sequenced parts in time. In many cases the turn-around time from broadcast to final assembly is less than 2 hours, with some components required in 30 minutes or less. With this time frame, there is little room for errors. In addition, quality inspection and poka-yoke must be implemented in the sequencing step to guarantee that the sequenced components match the assembly sequence perfectly. In many cases, suppliers must manage periodic sequence reversals, for example, when loading racks into a truck, since the first rack into the truck is the last one to come out. Employees and systems must also properly manage exceptional scenarios, such as re-processing damaged items after initial sequencing, skipping slots for scrapped items, etc. Just In Sequence implementations can only be successful if all of these processes are implemented correctly and all people involved understand what is at stake.
Limitations.
In many manufacturing operations, the actual production sequence cannot be planned ahead of time with enough certainty to enable sequencing. The main reason is that some manufacturing processes require re-work frequently so that a scheduled sequence becomes irrelevant. For example, painting operations in an automotive plant can have re-work levels of up to 20% (USA, Southern Europe).
References.
Stephan M. Wagner and Victor Silveira-Camargos, 2009, "Decision model for the application of just-in-sequence", in: Decision Sciences Institute Proceedings of the 40th annual conference, New Orleans, USA.


Ellington Electronics Technology Group

Ellington Electronics Technology Group 依頓電子科技股份有限公司 (simply known as Ellington PCB or Eton) is one of the leading printed circuit board (PCB) manufacturers in China. It is a Hong Kong based company which is listed on the Shanghai Stock Exchange on 1 July 2014. In Year 2018, the company was ranked Top 10 in China and 41st in the world by revenue.
History.
Ellington was founded in March 2000, principally engaged in the manufacture and sale of high precision and density 2/L to 20/L printed circuit board. With in-house surface finishing of Organic Solderability Preservative (OSP), Lead-Free Hot Air Solder Leveling (HASL), Immersion Gold / Silver / Tin. It manufactures for over 400 customers worldwide. Ellington's world ranking jumped from 88th in 2005 to 41st in 2018.
Operations.
The company's headquarter and production facilities are located in Zhongshan City, Guangdong Province, China. The 4 storey manufacturing plant has a total area of 2,600,000 ft2. Ellington focusing on production quality management and control, with the mission of " Quality Is Life ", the company is ISO/TS16949, ISO 9002, ISO 14001 and OHSAS 18001 certified. After the completion of its 3rd stage capacity expansion, the company currently generates an output of 4,200,000 ft2 (390,600 m2) per month and currently employs more than 6,500 people.
Ellington also has a logistic facility and administration office located in Tsuen Wan, Hong Kong.
The company produces multilayered rigid PCBs that are used in various electronic equipment worldwide including consumer electronics, telecommunication, computer and Computer Peripherals, automotive industry, automation, power supply and electronic test equipment.
Future.
Ellington has completed the 4th Stage of capacity expansion, generating a further 500,000 ft2 capacity for Automotive Industry only in an isolated production plant. A total production output of 7,000,000 ft2 multilayer PCB will be generated by the 5th Stage of capacity expansion plan after listing on Shanghai Stock Exchange.
Major Customer Base.
Apple, Bose Corporation, Continental AG, Delphi Technologies, Flextronics, Huawei, Jabil Circuit, Lite-On, Preh, Robert Bosch GmbH, Wistron Corporation, Valeo and 200+ others.


Tailstock

A tailstock, also known as a foot stock, is a device often used as part of an engineering lathe, wood-turning lathe, or used in conjunction with a rotary table on a milling machine.
It is usually used to apply support to the longitudinal rotary axis of a workpiece being machined. A lathe center is mounted in the tailstock, and inserted against the sides of a hole in the center of the workpiece. A tailstock has a Dead Center, while headstock has Live Center. A Tailstock is particularly useful when the workpiece is relatively long and slender. Failing to use a tailstock can cause "chatter," where the workpiece bends excessively while being cut.
It is also used on a lathe to hold drilling or reaming tools for machining a hole in the work piece. Unlike drilling with a drill press or a milling machine, the tool is stationary while the workpiece rotates. Holes can only be cut along the axis that the workpiece is set to spin.
Usually, the entire tailstock is moved to the approximate position that it will be needed by manually sliding it along its ways. There, it is locked in place and the tool mounted to it is moved with a leadscrew to the exact position where it is needed. When a cutting tool such as a drill bit or reamer is used, the feed is done with this leadscrew. The extendible portion of the tailstock is called the barrel, and usually has a Morse taper mount in the end of it to secure the drill or reamer. If the work is heavy the drill may be further secured from turning with a lathe dog as shown in the photo.


Centerless grinding

Centerless grinding is a machining process that uses abrasive cutting to remove material from a workpiece. Centerless grinding differs from centered grinding operations in that no spindle or fixture is used to locate and secure the workpiece; the workpiece is secured between two rotary grinding wheels, and the speed of their rotation relative to each other determines the rate at which material is removed from the workpiece.
Centerless grinding is typically used in preference to other grinding processes for operations where many parts must be processed in a short time.
Working principle.
In centerless grinding, the workpiece is held between two wheels, rotating in the same direction at different speeds, and a work-holding platform. One wheel, known as the grinding wheel (stationary wheel in the diagram), is on a fixed axis and rotates such that the force applied to the workpiece is directed downward, against the work-holding platform. This wheel usually performs the grinding action by having a higher tangential speed than the workpiece at the point of contact. The other wheel, known as the regulating wheel (moving wheel in the diagram), is movable. This wheel is positioned to apply lateral pressure to the workpiece, and usually has either a very rough or rubber-bonded abrasive to trap the workpiece.
The speed of the two wheels relative to each other provides the grinding action and determines the rate at which material is removed from the workpiece. During operation the workpiece turns with the regulating wheel, with the same linear velocity at the point of contact and (ideally) no slipping. The grinding wheel turns faster, slipping past the surface of the workpiece at the point of contact and removing chips of material as it passes.
Types.
There are three forms of centerless grinding, differentiated primarily by the method used to feed the workpiece through the machine.
Through-feed.
In through-feed centerless grinding, the workpiece is fed through the grinding wheels completely, entering on one side and exiting on the opposite. The regulating wheel in through-feed grinding is canted away from the plane of the grinding wheel in such a way as to provide an axial force component, feeding the workpiece through between the two wheels. Through-feed grinding can be very efficient because it does not require a separate feed mechanism; however, it can only be used for parts with a simple cylindrical shape.
End-feed.
In end-feed centerless grinding, the workpiece is fed axially into the machine on one side and comes to rest against an end stop; the grinding operation is performed, and then the workpiece is fed in the opposite direction to exit the machine. End-feed grinding is best for tapered workpieces.
In-feed.
In-feed centerless grinding is used to grind workpieces with relatively complex shapes, such as an hourglass shape. Before the process begins, the workpiece is loaded manually into the grinding machine and the regulating wheel is moved into place. The complexity of the part shapes and grinding wheel shapes required to grind them accurately prevent the workpiece from being fed axially through the machine.
Equipment.
Centerless grinding uses purpose-built centerless grinding machines. Such a machine will always include the grinding wheel, regulating wheel, and some means of supporting a workpiece. Modern machines may involve computer numerical control to allow automation and improve precision. Grinding wheels are interchangeable, to allow for different grits and shapes. Machines designed to accommodate through-feed grinding operations will allow the angle of the regulating wheel to be adjusted, to accommodate parts of different sizes.


Computer-aided manufacturing

Computer-aided manufacturing (CAM) also known as computer-aided modeling or computer-aided machining is the use of software to control machine tools in the manufacturing of work pieces. This is not the only definition for CAM, but it is the most common. It may also refer to the use of a computer to assist in all operations of a manufacturing plant, including planning, management, transportation and storage. Its primary purpose is to create a faster production process and components and tooling with more precise dimensions and material consistency, which in some cases, uses only the required amount of raw material (thus minimizing waste), while simultaneously reducing energy consumption.
CAM is now a system used in schools and lower educational purposes.
CAM is a subsequent computer-aided process after computer-aided design (CAD) and sometimes computer-aided engineering (CAE), as the model generated in CAD and verified in CAE can be input into CAM software, which then controls the machine tool. CAM is used in many schools alongside computer-aided design (CAD) to create objects.
Overview.
Traditionally, CAM has been numerical control (NC) programming tool, wherein two-dimensional (2-D) or three-dimensional (3-D) models of components are generated in CAD. As with other "computer-aided" technologies, CAM does not eliminate the need for skilled professionals such as manufacturing engineers, NC programmers, or machinists. CAM leverages both the value of the most skilled manufacturing professionals through advanced productivity tools, while building the skills of new professionals through visualization, simulation and optimization tools.
A CAM tool generally converts a model to a language the target machine in question understands, typically G-Code. The numerical control can be applied to machining tools, or more recently to 3D printers.
History.
Early commercial applications of CAM were in large companies in the automotive and aerospace industries; for example, Pierre Béziers work developing the CAD/CAM application UNISURF in the 1960s for car body design and tooling at Renault. Alexander Hammer at DeLaval Steam Turbine Company invented a technique to progressively drill turbine blades out of a solid metal block of metal with the drill controlled by a punch card reader in 1950.
Historically, CAM software was seen to have several shortcomings that necessitated an overly high level of involvement by skilled CNC machinists. Fallows created the first CAD software but this had severe shortcomings and was promptly taken back into the developing stage. CAM software would output code for the least capable machine, as each machine tool control added on to the standard G-code set for increased flexibility. In some cases, such as improperly set up CAM software or specific tools, the CNC machine required manual editing before the program will run properly. None of these issues were so insurmountable that a thoughtful engineer or skilled machine operator could not overcome for prototyping or small production runs; G-Code is a simple language. In high production or high precision shops, a different set of problems were encountered where an experienced CNC machinist must both hand-code programs and run CAM software.
The integration of CAD with other components of CAD/CAM/CAE Product lifecycle management (PLM) environment requires an effective CAD data exchange. Usually it had been necessary to force the CAD operator to export the data in one of the common data formats, such as IGES or STL or Parasolid formats that are supported by a wide variety of software.
The output from the CAM software is usually a simple text file of G-code/M-codes, sometimes many thousands of commands long, that is then transferred to a machine tool using a direct numerical control (DNC) program or in modern Controllers using a common USB Storage Device.
CAM packages could not, and still cannot, reason as a machinist can. They could not optimize toolpaths to the extent required of mass production. Users would select the type of tool, machining process and paths to be used. While an engineer may have a working knowledge of G-code programming, small optimization and wear issues compound over time. Mass-produced items that require machining are often initially created through casting or some other non-machine method. This enables hand-written, short, and highly optimized G-code that could not be produced in a CAM package.
At least in the United States, there is a shortage of young, skilled machinists entering the workforce able to perform at the extremes of manufacturing; high precision and mass production. As CAM software and machines become more complicated, the skills required of a machinist or machine operator advance to approach that of a computer programmer and engineer rather than eliminating the CNC machinist from the workforce.
Overcoming historical shortcomings.
Over time, the historical shortcomings of CAM are being attenuated, both by providers of niche solutions and by providers of high-end solutions. This is occurring primarily in three arenas:
Machining process.
Most machining progresses through many stages, each of which is implemented by a variety of basic and sophisticated strategies, depending on the part design, material, and software available.


Shielded metal arc welding

Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld.
An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. The workpiece and the electrode melts forming a pool of molten metal (weld pool) that cools to form a joint. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.
Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world's first and most popular welding processes. It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels (including stainless steel) but aluminium, nickel and copper alloys can also be welded with this method.
Development.
After the discovery of the short pulsed electric arc in 1800 by Humphry Davy and of the continuous electric arc in 1802 by Vasily Petrov, there was little development in electrical welding until Auguste de Méritens developed a carbon arc torch that was patented in 1881.
In 1885, Nikolay Benardos and Stanisław Olszewski developed carbon arc welding, obtaining American patents from 1887 showing a rudimentary electrode holder. In 1888, the consumable metal electrode was invented by Nikolay Slavyanov. Later in 1890, C. L. Coffin received for his arc welding method that utilized a metal electrode. The process, like SMAW, deposited melted electrode metal into the weld as filler.
Around 1900, Arthur Percy Strohmenger and Oscar Kjellberg released the first coated electrodes. Strohmenger used clay and lime coating to stabilize the arc, while Kjellberg dipped iron wire into mixtures of carbonates and silicates to coat the electrode. In 1912, Strohmenger released a heavily coated electrode, but high cost and complex production methods prevented these early electrodes from gaining popularity. In 1927, the development of an extrusion process reduced the cost of coating electrodes while allowing manufacturers to produce more complex coating mixtures designed for specific applications. In the 1950s, manufacturers introduced iron powder into the flux coating, making it possible to increase the welding speed.
In 1945 Karl Kristian Masden described an automated variation of SMAW, now known as gravity welding. It briefly gained popularity in the 1960s after receiving publicity for its use in Japanese shipyards though today its applications are limited. Another little used variation of the process, known as firecracker welding, was developed around the same time by George Hafergut in Austria. In 1964 laser welding was developed in Bell Laboratory with the intention of using this technology as a communication tool. Due to the large force of energy coupled with the small area of focus, this laser became a powerful heat source for cutting and tooling.
Operation.
To strike the electric arc, the electrode is brought into contact with the workpiece by a very light touch of the electrode to the base metal. The electrode is then pulled back slightly. This initiates the arc and thus the melting of the workpiece and the consumable electrode, and causes droplets of the electrode to be passed from the electrode to the weld pool. Striking an arc, which varies widely based upon electrode and workpiece composition, can be the hardest skill for beginners. The orientation of the electrode to workpiece is where most stumble; if the electrode is held at a perpendicular angle to the workpiece, the tip will likely stick to the metal, which will fuse the electrode to the workpiece, causing it to heat up very rapidly. The tip of the electrode needs to be at a lower angle to the workpiece, which allows the weld pool to flow out of the arc. As the electrode melts, the flux covering disintegrates, giving off shielding gases that protect the weld area from oxygen and other atmospheric gases. In addition, the flux provides molten slag which covers the filler as it travels from electrode to the weld pool. Once part of the weld pool, the slag floats to the surface and protects the weld from contamination as it solidifies. Once hardened, it must be chipped away to reveal the finished weld. As welding progresses and the electrode melts, the welder must periodically stop welding to remove the remaining electrode stub and insert a new electrode into the electrode holder. This activity, combined with chipping away the slag, reduces the amount of time that the welder can spend laying the weld, making SMAW one of the least efficient welding processes. In general, the operator factor, or the percentage of operator's time spent laying weld, is approximately 25%.
The actual welding technique utilized depends on the electrode, the composition of the workpiece, and the position of the joint being welded. The choice of electrode and welding position also determine the welding speed. Flat welds require the least operator skill, and can be done with electrodes that melt quickly but solidify slowly. This permits higher welding speeds.
Sloped, vertical or upside-down welding requires more operator skill, and often necessitates the use of an electrode that solidifies quickly to prevent the molten metal from flowing out of the weld pool. However, this generally means that the electrode melts less quickly, thus increasing the time required to lay the weld.
Quality.
The most common quality problems associated with SMAW include weld spatter, porosity, poor fusion, shallow penetration, and cracking.
Weld spatter, while not affecting the integrity of the weld, damages its appearance and increases cleaning costs. Secondary finishing services are often required due to the aesthetic appearance caused by the occurrence of molten splatter. It can be caused by excessively high current, a long arc, or arc blow, a condition associated with direct current characterized by the electric arc being deflected away from the weld pool by magnetic forces. Arc blow can also cause porosity in the weld, as can joint contamination, high welding speed, and a long welding arc, especially when low-hydrogen electrodes are used.
Defects to weld strength make welds prone to cracking. Porosity of the weld bead can cause serious weakening and is often detectable only via advanced nondestructive testing methods. Porosity occurs when the gases produced by the weld flux insufficiently shield the molten weld metal. An overexposed weld bead absorbs nitrogen, oxygen, and hydrogen from the atmosphere; these gases form tiny voids in the weld bead and are released while the weld cools. Poor fusion also affects the strength of the weld and is often easily visible. This is caused by low current, contaminated joint surfaces, or the use of an improper electrode. Shallow welds are weaker and can be mitigated by decreasing welding speed, increasing the current, or using a smaller electrode.
Other factors in cracking propensity include high content of carbon, alloy, or sulfur in the base material, especially if low-hydrogen electrodes and preheating are not employed. Furthermore, workpieces should not be excessively constrained, as this introduces residual stresses into the workpieces (and specifically into the weld) as they expand and contract due to heating and cooling. As the weld cools and contracts, this residual stress can cause cracking in the weld.
Safety.
SMAW welding, like other welding methods, can be a dangerous and unhealthy practice if proper precautions are not taken. The process uses an open electric arc, which presents a risk of burns which are prevented by personal protective equipment in the form of heavy leather gloves and long sleeve jackets. Additionally, the brightness of the weld area can lead to a condition called arc eye or flash burn, in which ultraviolet light causes inflammation of the cornea and can burn the retinas of the eyes. Welding helmets with dark face plates are worn to prevent this exposure, and in recent years, new helmet models have been produced that feature a face plate that self-darkens upon exposure to high amounts of UV light. To protect bystanders, especially in industrial environments, translucent welding curtains often surround the welding area. These curtains, made of a polyvinyl chloride plastic film, shield nearby workers from exposure to the UV light from the electric arc, but should not be used to replace the filter glass used in helmets.
In addition, the vaporizing metal and flux materials expose welders to dangerous gases and particulate matter. The smoke produced contains particles of various types of oxides. The size of the particles in question tends to influence the toxicity of the fumes, with smaller particles presenting a greater danger. Additionally, gases like carbon dioxide and ozone can form, which can prove dangerous if ventilation is inadequate. Some of the latest welding masks are fitted with an electric powered fan to help disperse harmful fumes.
Application and materials.
Shielded metal arc welding is one of the world's most popular welding processes, accounting for over half of all welding in some countries. Because of its versatility and simplicity, it is particularly dominant in the maintenance and repair industry, and is heavily used in the construction of steel structures and in industrial fabrication. In recent years its use has declined as flux-cored arc welding has expanded in the construction industry and gas metal arc welding has become more popular in industrial environments. However, because of the low equipment cost and wide applicability, the process will likely remain popular, especially among amateurs and small businesses where specialized welding processes are uneconomical and unnecessary.
SMAW is often used to weld carbon steel, low and high alloy steel, stainless steel, cast iron, and ductile iron. While less popular for non-ferrous materials, it can be used on nickel and copper and their alloys and, in rare cases, on aluminium. The thickness of the material being welded is bounded on the low end primarily by the skill of the welder, but rarely does it drop below . No upper bound exists: with proper joint preparation and use of multiple passes, materials of virtually unlimited thicknesses can be joined. Furthermore, depending on the electrode used and the skill of the welder, SMAW can be used in any position.
Equipment.
Shielded metal arc welding equipment typically consists of a constant current welding power supply and an electrode, with an electrode holder, a ground clamp, and welding cables (also known as welding leads) connecting the two.
Power supply.
The power supply used in SMAW has constant current output, ensuring that the current (and thus the heat) remains relatively constant, even if the arc distance and voltage change. This is important because most applications of SMAW are manual, requiring that an operator hold the torch. Maintaining a suitably steady arc distance is difficult if a constant voltage power source is used instead, since it can cause dramatic heat variations and make welding more difficult. However, because the current is not maintained absolutely constant, skilled welders performing complicated welds can vary the arc length to cause minor fluctuations in the current.
The preferred polarity of the SMAW system depends primarily upon the electrode being used and the desired properties of the weld. Direct current with a negatively charged electrode (DCEN) causes heat to build up in the parent material, increasing the electrode melting rate and decreasing the depth of the weld. Reversing the polarity so that the electrode is positively charged (DCEP) and the workpiece is negatively charged increases the weld penetration. With alternating current the polarity changes over 100 times per second, creating an even heat distribution and providing a balance between electrode melting rate and penetration.
Typically, the equipment used for SMAW consists of a step-down transformer and for direct current models a rectifier, which converts alternating current into direct current. Because the power normally supplied to the welding machine is high-voltage alternating current, the welding transformer is used to reduce the voltage and increase the current. As a result, instead of 220 V at 50 A, for example, the power supplied by the transformer is around 17–45 V at currents up to 600 A. A number of different types of transformers can be used to produce this effect, including multiple coil and inverter machines, with each using a different method to manipulate the welding current. The multiple coil type adjusts the current by either varying the number of turns in the coil (in tap-type transformers) or by varying the distance between the primary and secondary coils (in movable coil or movable core transformers). Inverters, which are smaller and thus more portable, use electronic components to change the current characteristics.
Electrical generators and alternators are frequently used as portable welding power supplies, but because of lower efficiency and greater costs, they are less frequently used in industry. Maintenance also tends to be more difficult, because of the complexities of using a combustion engine as a power source. However, in one sense they are simpler: the use of a separate rectifier is unnecessary because they can provide either AC or DC. However, the engine driven units are most practical in field work where the welding often must be done out of doors and in locations where transformer type welders are not usable because there is no power source available to be transformed.
In some units the alternator is essentially the same as that used in portable generating sets used to supply mains power, modified to produce a higher current at a lower voltage but still at the 50 or 60 Hz grid frequency. In higher-quality units an alternator with more poles is used and supplies current at a higher frequency, such as 400 Hz. The smaller amount of time the high-frequency waveform spends near zero makes it much easier to strike and maintain a stable arc than with the cheaper grid-frequency sets or grid-frequency mains-powered units.
Electrode.
The choice of electrode for SMAW depends on a number of factors, including the weld material, welding position and the desired weld properties. The electrode is coated in a metal mixture called flux, which gives off gases as it decomposes to prevent weld contamination, introduces deoxidizers to purify the weld, causes weld-protecting slag to form, improves the arc stability, and provides alloying elements to improve the weld quality. Electrodes can be divided into three groups—those designed to melt quickly are called "fast-fill" electrodes, those designed to solidify quickly are called "fast-freeze" electrodes, and intermediate electrodes go by the name "fill-freeze" or "fast-follow" electrodes. Fast-fill electrodes are designed to melt quickly so that the welding speed can be maximized, while fast-freeze electrodes supply filler metal that solidifies quickly, making welding in a variety of positions possible by preventing the weld pool from shifting significantly before solidifying.
The composition of the electrode core is generally similar and sometimes identical to that of the base material. But even though a number of feasible options exist, a slight difference in alloy composition can strongly impact the properties of the resulting weld. This is especially true of alloy steels such as HSLA steels. Likewise, electrodes of compositions similar to those of the base materials are often used for welding nonferrous materials like aluminium and copper. However, sometimes it is desirable to use electrodes with core materials significantly different from the base material. For example, stainless steel electrodes are sometimes used to weld two pieces of carbon steel, and are often utilized to weld stainless steel workpieces with carbon steel workpieces.
Electrode coatings can consist of a number of different compounds, including rutile, calcium fluoride, cellulose, and iron powder. Rutile electrodes, coated with 25%–45% TiO2, are characterized by ease of use and good appearance of the resulting weld. However, they create welds with high hydrogen content, encouraging embrittlement and cracking. Electrodes containing calcium fluoride (CaF2), sometimes known as basic or low-hydrogen electrodes, are hygroscopic and must be stored in dry conditions. They produce strong welds, but with a coarse and convex-shaped joint surface. Electrodes coated with cellulose, especially when combined with rutile, provide deep weld penetration, but because of their high moisture content, special procedures must be used to prevent excessive risk of cracking. Finally, iron powder is a common coating additive that increases the rate at which the electrode fills the weld joint, up to twice as fast.
To identify different electrodes, the American Welding Society established a system that assigns electrodes with a four- or five-digit number. Covered electrodes made of mild or low alloy steel carry the prefix "E", followed by their number. The first two or three digits of the number specify the tensile strength of the weld metal, in thousand pounds per square inch (ksi). The penultimate digit generally identifies the welding positions permissible with the electrode, typically using the values 1 (normally fast-freeze electrodes, implying all position welding) and 2 (normally fast-fill electrodes, implying horizontal welding only). The welding current and type of electrode covering are specified by the last two digits together. When applicable, a suffix is used to denote the alloying element being contributed by the electrode.
Common electrodes include the E6010, a fast-freeze, all-position electrode with a minimum tensile strength of which is operated using DCEP, and provides deep weld penetration with a forceful arc capable of burning through light rust or oxides on the workpiece. E6011 is similar except its flux coating allows it to be used with alternating current in addition to DCEP. E7024 is a fast-fill electrode, used primarily to make flat or horizontal fillet welds using AC, DCEN, or DCEP. Examples of fill-freeze electrodes are the E6012, E6013, and E7014, all of which provide a compromise between fast welding speeds and all-position welding.
Process variations.
Though SMAW is almost exclusively a manual arc welding process, one notable process variation exists, known as gravity welding or gravity arc welding. It serves as an automated version of the traditional shielded metal arc welding process, employing an electrode holder attached to an inclined bar along the length of the weld. Once started, the process continues until the electrode is spent, allowing the operator to manage multiple gravity welding systems. The electrodes employed (often E6027 or E7024) are coated heavily in flux, and are typically in length and about thick. As in manual SMAW, a constant current welding power supply is used, with either negative polarity direct current or alternating current. Due to a rise in the use of semiautomatic welding processes such as flux-cored arc welding, the popularity of gravity welding has fallen as its economic advantage over such methods is often minimal. Other SMAW-related methods that are even less frequently used include firecracker welding, an automatic method for making butt and fillet welds, and massive electrode welding, a process for welding large components or structures that can deposit up to of weld metal per hour.


Product life-cycle management (marketing)

Product life-cycle management (PLM) is the succession of strategies by business management as a product goes through its life-cycle. The conditions in which a product is sold (advertising, saturation) changes over time and must be managed as it moves through its succession of stages.
Goals.
The goals of product life cycle management (PLM) are to reduce time to market, improve product quality, reduce prototyping costs, identify potential sales opportunities and revenue contributions, maintain and sustain operational serviceability, and reduce environmental impacts at end-of-life. To create successful new products the company must understand its customers, markets and competitors. Product Lifecycle Management (PLM) integrates people, data, processes and business systems. It provides product information for companies and their extended supply chain enterprise. PLM solutions help organizations overcome the increased complexity and engineering challenges of developing new products for the global competitive markets.
Product life cycle.
The concept of product life cycle (PLC) concerns the life of a product in the market with respect to business/commercial costs and sales measures. The product life cycle proceeds through multiple phases, involves many professional disciplines, and requires many skills, tools and processes. PLC management makes the following three assumptions:
Once the product is designed and put into the market, the offering should be managed efficiently for the buyers to get value from it. Before entering into any market complete analysis is carried out by the industry for both external and internal factors including the laws and regulations, environment, economics, cultural values and market needs. From the business perspective, as a good business, the product needs to be sold before it finishes its life. In terms of profitability, expiry may jolt the overall profitability of the business therefore there are few strategies, which are practiced to ensure that the product is sold within the defined period of maturity.
Extending the product life cycle.
Extending the product life cycle by improving sales, can be done through
Something important to notice is that all these techniques rely on advertising to become known. Advertising needs the others to target other potential customers and not the same over and over again.
Characteristics of PLC stages.
There are the following major product life cycle stages:
Identifying PLC stages.
Identifying the stage of a product is an art more than a science, but it's possible to find patterns in some of the general product features at each stage. Identifying product stages when the product is in transition is very difficult. More recently, it has been shown that user-generated contents (UGC) (e.g., in the form of online product reviews) has the potential to reveal buyer personality characteristics that can in turn be used to identify product life cycle stage.


Flow-shop scheduling

Flow-shop scheduling is an optimization problem in computer science and operations research. It is a variant of optimal job scheduling. In a general job-scheduling problem, we are given "n" jobs "J"1, "J"2, ..., "Jn" of varying processing times, which need to be scheduled on "m" machines with varying processing power, while trying to minimize the makespan – the total length of the schedule (that is, when all the jobs have finished processing). In the specific variant known as "flow-shop scheduling", each job contains exactly "m" operations. The "i"-th operation of the job must be executed on the "i"-th machine. No machine can perform more than one operation simultaneously. For each operation of each job, execution time is specified.
Flow-shop scheduling is a special case of job-shop scheduling where there is strict order of all operations to be performed on all jobs. Flow-shop scheduling may apply as well to production facilities as to computing designs. A special type of flow-shop scheduling problem is the permutation flow-shop scheduling problem in which the processing order of the jobs on the resources is the same for each subsequent step of processing.
In the standard three-field notation for optimal-job-scheduling problems, the flow-shop variant is denoted by F in the first field. For example, the problem denoted by " F3|formula_1|formula_2" is a 3-machines flow-shop problem with unit processing times, where the goal is to minimize the maximum completion time.
Formal definition.
There are "m" machines and "n" jobs. Each job contains exactly "m" operations. The "i"-th operation of the job must be executed on the "i"-th machine. No machine can perform more than one operation simultaneously. For each operation of each job, execution time is specified.
Operations within one job must be performed in the specified order. The first operation gets executed on the first machine, then (as the first operation is finished) the second operation on the second machine, and so on until the "m"-th operation. Jobs can be executed in any order, however. Problem definition implies that this job order is exactly the same for each machine. The problem is to determine the optimal such arrangement, i.e. the one with the shortest possible total job execution makespan.
Sequencing performance measurements (γ).
The sequencing problem can be stated as determining a sequence S such that one or several sequencing objectives are optimized.
detailed discussion of performance measurement can be found in Malakooti(2013).
Complexity of flow-shop scheduling.
As presented by Garey et al. (1976), most of extensions of the flow-shop-scheduling problems are NP-hard and few of them can be solved optimally in O(nlogn); for example, F2|prmu|Cmax can be solved optimally by using Johnson's Rule.
Taillard provides substantial benchmark problems for scheduling flow shops, open shops, and job shops.
Solution methods.
The proposed methods to solve flow-shop-scheduling problems can be classified as exact algorithm such as branch and bound and heuristic algorithm such as genetic algorithm.
Minimizing makespan, Cmax.
F2|prmu|Cmax and F3|prmu|Cmax can be solved optimally by using Johnson's Rule but for general case there is no algorithm that guarantee the optimality of the solution.
The flow shop contains n jobs simultaneously available at time zero and to be processed by two machines arranged in series with unlimited storage in between them. The processing time of all jobs are known with certainty. It is required to schedule n jobs on machines so as to minimize makespan. The Johnson's rule for scheduling jobs in two-machine flow shop is given below.
In an optimal schedule, job i precedes job j if "min{p1i,p2j} < min{p1j,p2i}". Where as, p1i is the processing time of job i on machine 1 and p2i is the processing time of job i on machine 2. Similarly, p1j and p2j are processing times of job j on machine 1 and machine 2 respectively.
For Johnson's algorithm:
Johnson's algorithm:
This type schedule is referred as SPT(1)–LPT(2) schedule.
A detailed discussion of the available solution methods are provided by Malakooti (2013).


Foundry Products Operations

Foundry Products Operations was a subsidiary operation of the Cincinnati Milling Machine Company (CMM), a company which no longer exists. Some parts of the company evolved into the present Milacron, Inc. and Cincinnati Machine. CMM relied heavily on castings for the manufacturing of its machine tool products. The castings were produced at Cincinnati foundries owned by CMM (and later, Milacron, Inc.) and at foundries independent of CMM, between 1907 and 1988.
History.
Beginnings of CMM reliance on castings.
In 1884 the Cincinnati Screw and Tap Company was incorporated. The company was in the business of making screws and taps, but also began to make machine tools. A basic component in machine tools at this time was gray iron castings. The company bought castings from jobbing foundries for the machine tools it manufactured. Some of the Cincinnati local foundries which supplied to the machine tool company included the Blackburn Foundry, Buckeye Foundry Company, the Steel Foundry Company (Cincinnati) and others.
In 1889 the screw and tap business was sold off, as the company focused on machine tool business. It was renamed as the Cincinnati Milling Machine Co. (CMM). CMM continued to operate in the central business district of Cincinnati and purchased castings from a number of local foundries.
In 1905 the company was sold in total to Frederick A. Geier, who became president. Geier had been a partner in the concern previously. Until this time the company had had some problems with the locations in the business district: at least one flood and a fire had caused it to relocate.
Relocation to Oakley.
In October 1906 CMM announced plans for a new vertically integrated factory to be built in Oakley, a suburb of Cincinnati. A site was purchased which was named the Factory Colony. This site was developed to include a two-story administration building 62 × , a foundry building 62 × , a building for cleaning castings and storing 62 × , a charging building 62 × , and a pattern shop 62 × . These buildings would be all of brick and steel construction. A few months later the company announced the foundry would be 350 × , with the pattern shop to be 50 × . A power house would also be erected with a size of 75 × 100 feet. The foundry was planned to provide castings to all companies which would locate to the new industrial park.
Geier reasoned a captive foundry operation was needed because "the uncertain supply of castings had been a great handicap to production at a time when demand was far greater than our ability to supply".
A few months after making the construction announcement, CMM announced they were leasing a foundry on Patternson Street in Cincinnati, to be occupied be the Modern Foundry until the construction was completed in Oakley. The Modern Foundry was the beginnings of what became the Foundry Products Operations of the Cincinnati Milling Machine Company.
The foundry was erected by the Interstate Engineering Company, opening in 1907. It was the first production facility in the new industrial park, as a separate organization called the Modern Foundry and was located at the corner of Marburg and Disney Street in Oakley. The new foundry was fully operational by 1908 and could melt 30 tons per day in its cupola furnaces.
The foundry also organized with other foundries in Cincinnati: Lunkenheimer, Buckeye Foundry Company and the John B. Morris Foundry, to form the Associated Foundries of Cincinnati, supplying castings to Cincinnati industry. The first manager of the Modern Foundry was Walter H. Geier.
By the mid-1930s the Factory Colony was considered one of the world's largest manufacturers of machine tools and employed thousands of workers.
Chosen to represent the foundry industry in a mural.
Winold Reiss was contracted to produce murals depicting workers in Cincinnati industries, for the new Cincinnati Union Terminal. To depict the foundry industry, he visited the Modern Foundry to get ideas and set a scene for one of the murals, called "Foundry and Machine Shop Products". In this mural, a man (modeled by Joseph Schwope, 1898–1980) is skimming a ladle of iron, while an iron pourer (modeled by Bill Rengering, 1901–1985) pours a mold. A metallurgist (modeled by Emil Weston, 1900–1990) measures the metal temperature using an optical pyrometer. In the background a cupola tender (Bill Ennix, 1886–1944) watches over the work. One source credits the model for the cupola tender as being Howard Fredericks.
A copy of the original photograph is shown in the book "They Built a City: 150 Years of Industrial Cincinnati".
After visiting the Modern Foundry for a couple days, and after everything was arranged as Reiss wanted to capture the depiction of the foundry industry, the photograph was taken during the pouring of a mold. Reiss made a sketch of the elements he wanted to include from the photograph, simplifying certain elements for his mural. He submitted this sketch to the Ravenna Mosaic Company of Italy for production into the tesserae medium of the mosaic. The glass tesserae pieces were attached to paper and shipped to Cincinnati Union Terminal. The paper-backed pieces were pressed into the plaster on the terminal wall. Interstitial places were filled with colored mortar. In 1973, when the terminal concourse was to be torn down, this mural and 13 others by Reiss were carefully removed and transported for display at Cincinnati/Northern Kentucky International Airport.
Preparations for a new expansion, gearing up for war.
In the early 1930s Frederick V. Geier (son of Frederick A. Geier) was sent to Germany to explore the possibility of establishing an operation there for manufacturing machine tools. He was shocked by the scale of industrial development and concluded a war in Europe was imminent. He believed that the United States needed to make changes to support its needs and those of its allies.
The foundry operation was licensed to produce iron under the Meehanite process in 1935 for the cupola operation. In 1937 the Blackburn Foundry was taken over to support production of large castings. In 1938, based on his studies of what was happening in Europe and despite a deep recession, Geier launched a program to double the plant size, including construction of a new foundry.
New Foundry.
The New Foundry opened and poured its first heat by December 1940, about a year before the Attack on Pearl Harbor. With the opening of the New Foundry, the company tore down the old Modern Foundry. At this site, it developed additional machining and assembly space, which enabled a seven-fold increase in production during World War II. The Modern Foundry poured its last heat in 1941.
The Metal Fabricating Division foundry, as it came to be called, supplied all the needs of the Cincinnati Milling Machine Company and its successor, Milacron, Inc. At least three buildings were constructed, totaling more than .
 By 1942 the Cincinnati Milling Machine Company Foundry (CMM Co. Foundry) was producing 35,000 tons of castings, with an additional 32,000 tons being purchased from other sources. Melting in the New Foundry was done by up to four cupola furnaces. Production in the foundry was around the clock, seven days a week. Additional castings were needed, and the 'Mill' turned to outside Cincinnati local foundries. At total of 27 outside foundries were also supplying castings to the Mill.
Army-Navy "E" Award.
Cincinnati Milling Machine received the prestigious Army-Navy "E" Award on March 6, 1942, in part through the efforts of the New Foundry and the other local foundries in supplying thousands of castings, which were used to produce 17,511 machine tools in 1942 alone to gear up for war. Late in the World War II era, they dropped production considerably, to less than half of that amount, to about 15,000 tons per year.
Post war.
At the end of the war and into the 1950s, production stabilized at about 12,000 tons per year, with purchased castings at about 3,000 tons per year. The CMM Co. Foundry also produced castings for direct sales to other customers, but at a low rate of about 1,000 tons per year. Because the foundry was wholly owned by CMM, other machine tool makers were reluctant to have their competitor making castings for them. In the late postwar period, Cincinnati local foundries had an excess production capacity.
The production of castings was similar to the way they were made since the early days of founding. Molding was done with green sand until sometime in the 1960s or 1970s, when the furan molding process was adopted for medium and large sized castings. Melting continued using the cupola. Most requirements on the foundry were for gray iron, the material normally used in machine tool castings. With the discovery of ductile iron, the foundry began producing ductile in the 1950s, using open ladle treatments or the Gazal porous plug process. Not many machine tool parts were needed in ductile iron.
Castings for overseas production facilities.
In 1964 Milacron constructed an entirely new foundry in England to supply castings for its European machine tool business. This foundry was known as Cincinnati Milacron Ltd, Foundry Operations, Tamworth, England. In the 1970s and 1980s the company was the largest single employer in Biggleswade, Bedfordshire, England.
Change in the 1970s.
In the 1970s, great changes came to the machine tool industry, especially in Cincinnati. Milacron diversified its interests by developing machines that made plastic products . A large part of its success in making machinery was in the use of ductile iron in the plastic injection machinery.
Sale to Cast-Fab Technologies.
In 1988, Cincinnati Milacron, Inc. restructured and reorganized the company. It sold the Met-Fab Division facility, including the Oakley foundry. In the previous ten-year period, Milacron had invested more than $8 million in the plant.
The sale represented the end of the Foundry Products Operations. The modernized New Foundry was adapted as a metalcasting operation that supplies many companies and customers with a full range of gray and ductile iron castings. Named Cast-Fab Technologies, Inc., this foundry ceased operation in November 2016, transferring remaining business to Elyria Cast-Fab.
As of the end of 2012, the entire 100-acre site that once held the Cincinnati Milling Machine Company was cleared to bare ground.


Pou Chen Corporation

Pou Chen Corporation  (Taiwan Stock Exchange Stock Code: 9904), or Pou Chen, is a leading footwear manufacturer in Taiwan, and the largest branded athletic and casual footwear manufacturer in the world. It is headquartered in Taichung City, Taiwan.
The Group was founded in Fuxing, Changhwa in 1969 by Tsai's family. It focuses on the manufacturing of athletic and casual footwear on an OEM/ODM basis for major global brands such as Nike, Adidas, Asics, Clarks, Reebok, Puma, New Balance, Crocs, Merrell, Timberland, Converse and Salomon. It owns production lines in China, Indonesia, Mexico and Vietnam. Its subsidiary, Yue Yuen Industrial Holdings , is the world's largest athletic shoe manufacturer which focuses on footwear material manufacturing.
In April 2014, 40,000 workers were protesting Yue Yuen Industrial Holding failure to pay the full social security and house renting contribution. The protests were triggered by a staff member who worked for 18 years at Yue Yuen who did not get her full pension. The company did not pay 250 yuan per month to the employee that they should have.
Besides footwear business, Pou Chen used to engage in electronics business by investing Global Brands Manufacture Limited (GBM), which is engaged in manufacturing printed circuit boards and assembling. However, the erupted global financial crisis in 2008 caused the group to readjust its business strategy and to dispose its 40% stake in GBM by auction in March 2010.


Printed circuit board milling

Printed circuit board milling (also: isolation milling) is the milling process used for removing areas of copper from a sheet of printed circuit board (PCB) material to recreate the pads, signal traces and structures according to patterns from a digital circuit board plan known as a "layout file". Similar to the more common and well known chemical PCB etch process, the PCB milling process is subtractive: material is removed to create the electrical isolation and ground planes required. However, unlike the chemical etch process, PCB milling is typically a non-chemical process and as such it can be completed in a typical office or lab environment without exposure to hazardous chemicals. High quality circuit boards can be produced using either process. In the case of PCB milling, the quality of a circuit board is chiefly determined by the system's true, or weighted, milling accuracy and control as well as the condition (sharpness, temper) of the milling bits and their respective feed/rotational speeds. By contrast, in the chemical etch process, the quality of a circuit board depends on the accuracy and/or quality of the mask used to protect the copper from the chemicals and the state of the etching chemicals.
Advantages.
PCB milling has advantages for both prototyping and some special PCB designs. The biggest benefit is that one does not have to use chemicals to produce PCBs.
When creating a prototype, outsourcing a board takes time. An alternative is to make a PCB in-house. Using the wet process, in-house production presents problems with chemicals and disposing thereof. High-resolution boards using the wet process are hard to achieve and still, when done, one still has to drill and eventually cut out the PCB from the base material.
CNC machine prototyping can provide a fast-turnaround board production process without the need for wet processing. If a CNC machine is already used for drilling, this single machine could carry out both parts of the process, drilling and milling. A CNC machine is used to process drilling, milling and cutting.
Many boards that are simple for milling would be very difficult to process by wet etching and manual drilling afterward in a laboratory environment without using top-of-the-line systems that usually cost many times more than CNC milling machines.
In mass production, milling is unlikely to replace etching although the use of CNC is already standard practice for drilling the boards.
Hardware.
A PCB milling system is a single machine that can perform all of the required actions to create a prototype board, with the exception of inserting "vias" and "through hole plating". Most of these machines require only a standard AC mains outlet and a shop-type vacuum cleaner for operation.
Software.
Software for milling PCBs is usually delivered by the CNC machine manufacturer. Most of the packages can be split in two main categories – raster and vector.
Software that produces tool paths using raster calculation method tends to have lower resolution of processing than the vector based software since it relies on the raster information it receives.
Mechanical system.
The mechanics behind a PCB milling machine are fairly straightforward and have their roots in CNC milling technology. A PCB milling system is similar to a miniature and highly accurate NC milling table. For machine control, positioning information and machine control commands are sent from the controlling software via a serial port or parallel port connection to the milling machine's on-board controller. The controller is then responsible for driving and monitoring the various positioning components which move the milling head and gantry and control the spindle speed. Spindle speeds can range from 30,000 RPM to 100,000 RPM depending on the milling system, with higher spindle speeds equating to better accuracy, in a nutshell the smaller the tool diameter the higher RPM you need. Typically this drive system comprises non-monitored stepper motors for the X/Y axis, an on-off non-monitored solenoid, pneumatic piston or lead screw for the Z-axis, and a DC motor control circuit for spindle speed, none of which provide positional feedback. More advanced systems provide a monitored stepper motor Z-axis drive for greater control during milling and drilling as well as more advanced RF spindle motor control circuits that provide better control over a wider range of speeds.
X and Y-axis control.
For the X and Y-axis drive systems most PCB milling machines use stepper motors that drive a precision lead screw. The lead screw is in turn linked to the gantry or milling head by a special precision machined connection assembly. To maintain correct alignment during milling, the gantry or milling head's direction of travel is guided along using linear or dovetailed bearing(s). Most X/Y drive systems provide user control, via software, of the milling speed, which determines how fast the stepper motors drive their respective axes.
Z-axis control.
Z-axis drive and control are handled in several ways. The first and most common is a simple solenoid that pushes against a spring. When the solenoid is energized it pushes the milling head down against a spring stop that limits the downward travel. The rate of descent as well as the amount of force exerted on the spring stop must be manually set by mechanically adjusting the position of the solenoid's plunger. The second type of Z-axis control is through the use of a pneumatic cylinder and a software-driven gate valve. Due to the small cylinder size and the amount of air pressure used to drive it there is little range of control between the up and down stops. Both the solenoid and pneumatic system cannot position the head anywhere other than the endpoints, and are therefore useful for only simple 'up/down' milling tasks. The final type of Z-axis control uses a stepper motor that allows the milling head to be moved in small accurate steps up or down. Further, the speed of these steps can be adjusted to allow tool bits to be eased into the board material rather than hammered into it. The depth (number of steps required) as well as the downward/upward speed is under user control via the controlling software.
One of the major challenges with milling PCBs is handling variations in flatness. Since conventional etching techniques rely on optical masks that sit right on the copper layer they can conform to any slight bends in the material so all features are replicated faithfully.
When milling PCBs however, any minute height variations encountered when milling will cause conical bits to either sink deeper (creating a wider cut) or rise off the surface, leaving an uncut section. Before cutting some systems perform height mapping probes across the board to measure height variations and adjust the Z values in the G-code beforehand.
Tooling.
PCBs may be machined with conventional endmills, conical d-bit cutters, and spade mills. D-bits and spade mills are cheap and as they have a small point allow the traces to be close together. Taylor's equation, Vc Tn = C, can predict tool life for a given surface speed.
Alternatives.
A method with similar advantages to mechanical milling is laser etching and laser drilling. Etching PCBs with lasers offers the same advantages as mechanical milling in regards to quick turnaround times, but the nature of the laser etching process is preferable to both milling and chemical etching when it comes to physical variations exerted on the object. Whereas mechanical milling and chemical etching exact physical stress on the board, laser etching offers non-contact surface removal, making it a superior option for PCBs where precision and geometric accuracy are at a premium, such as RF and microwave designs. Laser drilling is more precise, has extremely low power consumption compared with other techniques, requires less maintenance, does not use lubricants or drill bits, low rates of wear, does not use abrasive materials, does not ruin the boards, is more eco friendly, and in the most high-powered machines, the drilling is instant, but is expensive. An additional emerging alternative to milling and laser etching is an additive approach based upon printing the conductive trace. Such PCB printers come at a range of price points and with differing features but also offer rapid in-house circuit manufacture, with very little to no waste. An example of such a technology that produces simpler, low layer count PCBs is Voltera. A system at the higher layer-count end of the additive manufacturing approach is Nano Dimension's DragonFly technology which prints complex high layer count circuits as well as electro-mechanical parts.


Macor

Macor is the trademark for a machinable glass-ceramic developed and sold by Corning Inc. It is a white material that looks somewhat like porcelain. Macor is a good thermal insulator and is stable up to temperatures of 1000 °C, with very little thermal expansion or outgassing. It can be machined using standard metalworking tools.
Composition.
Macor is made up of fluorphlogopite mica in a borosilicate glass matrix. Its composition is roughly: 46% silica (SiO2), 17% magnesium oxide (MgO), 16% aluminium oxide (Al2O3), 10% potassium oxide (K2O), 7% boron trioxide (B2O3), 4% fluorine (F).
Properties.
Macor has a density of 2.52 g/cm3, a Young's modulus of 66.9 GPa at 25 °C, a specific stiffness of 26.55 m2s−2, a Poisson’s Ratio of 0.29 and a thermal conductivity of 1.46 W/(m·K). It has a low-temperature (25 to 300 °C) thermal expansion of 9.3 K−1. Its compressive strength is 50 lb/in2 (~350 MPa). Nominal engineering properties are comparable to borosilicate glass.
Extremely machinable, Macor offers tight-tolerance capabilities, allowing complicated shape design (optimal performances up to
±0.013 mm for dimensions, < 0.5 μm for finished surface and up to 0.013 μm for polished surface). Macor remains continuously stable at 800 °C, with a maximum peak at 1000 °C under no load, and unlike ductile materials, doesn’t creep or deform.
Its coefficient of thermal expansion readily matches most metals and sealing glasses. As an electric insulator, particularly at high temperatures, it is excellent at high voltages and a broad spectrum of frequencies.
Macor comes in a standard size maxi slab (about ). Components, bars, rods and plates can be machined within the size of this slab (hand tools can be used).
Applications.
Macor is used in the following applications:
Safety.
There are no major safety concerns or toxic effects associated with Macor. The dust created when machining it can be an irritant, and inhalation should be avoided.
Machining guidelines.
Key factors for successful machining are proper machining speeds and coolant. Macor can be machined with high-speed steel tools, but carbide tools are recommended for longer wear. Best results achieved by using a water-soluble coolant (such as Cimstar 40 – Pink) especially formulated for cutting and grinding glass or ceramics. Note: No post-firing is required after machining.


Run-out

Run-out or runout is an inaccuracy of rotating mechanical systems, specifically that the tool or shaft does not rotate exactly in line with the main axis. For example; when drilling, run-out will result in a larger hole than the drill's nominal diameter due to the drill
being rotated eccentrically (off axis instead of in line). In the case of bearings, run-out will cause vibration of the machine and increased loads on the bearings.
Run-out is dynamic and cannot be compensated. If a rotating component, such as a drill chuck, does not hold the drill centrally, then as it rotates the rotating drill will turn about a secondary axis.
Run-out has two main forms:
In addition, irregular run-out is the result of worn or rough bearings which can manifest itself as either axial or radial run-out.
Runout will be present in any rotating system and, depending on the system, the different forms may either combine increasing total runout, or cancel reducing total runout. At any point along a tool or shaft it is not possible to determine whether runout is axial or radial; only by measuring along the axis can they be differentiated.
Absolute alignment is impossible; a degree of error will always be present.
Radial run-out.
Radial run-out is the result of a rotating component running off centre, such as a ball bearing with an offset centre. This means that the rotating tool or shaft, instead of being centrally aligned, will rotate about a secondary axis. In general, cutting tools are more tolerant of radial run-out since the edges are parallel to the line of cutting tending to keep the tool tip aligned. However, a rotating shaft may be less tolerant of radial run-out since the centre of gravity is displaced by the amount of run-out.
Axial run-out.
Axial run-out is the result of a rotating component not being parallel with the axis, such as a drill chuck not holding the drill exactly in line with the axis. In general, cutting tools are less tolerant of axial run-out since the tool tip tends to dig in and further increase run-out. However, a shaft may be more tolerant of axial run-out since the centre of gravity is displaced less.
Measurement.
Typically run-out is measured using a dial indicator pressed against the rotating component while it is turned. Total indicated run-out (TIR) is a technician's term for the measured run-out of any rotating system, including all forms of run-out, at the measured point.


Precision engineering

Precision engineering is a subdiscipline of electrical engineering, software engineering, electronics engineering, mechanical engineering, and optical engineering concerned with designing machines, fixtures, and other structures that have exceptionally low tolerances, are repeatable, and are stable over time. These approaches have applications in machine tools, MEMS, NEMS, optoelectronics design, and many other fields.
Precision engineering is a branch of engineering that focus on the design, development and manufacture of product with high levels of accuracy and repeatability.
it involves the use of advanced technologies and techniques to achieve tight tolerance and dimensional control is the manufacturing process.
Overview.
Professors Hiromu Nakazawa and Pat McKeown provide the following list of goals for precision engineering:


Saleen Special Vehicles

Saleen Special Vehicles or SSV, was a Saleen-owned and Saleen-operated small-volume, specialty vehicle assembly plant located at 1225 East Maple Road in Troy, Michigan. The building housing this facility was previously a Stanley door-manufacturing facility prior to renovations performed by Saleen to manufacture the Ford GT (which occurred between 2003 and 2006). Prior to use by Stanley, the building was the headquarters of the AMT Corporation, known by many as the premier manufacturer of 1:25th scale model cars in the 1950s, 1960s and 1970s. The plant was last used principally for production of the Saleen S331 Sport Truck, and various models of Saleen Mustangs. Additionally, following Steve Saleen's departure from the company, the core of Saleen's exterior styling and engineering was relocated to Saleen, Troy.
Manufacturing Facilities.
SSV boasts a single assembly line outfitted to accommodate mixed-product production, a high-efficiency paint shop capable of high-bake paint cure processes, fabrication shop, and specialty car assembly area. Saleen also conducted painting operations for the Dodge Viper in the paint shop at Saleen Special Vehicles. Based upon the production rates achieved during the manufacture of the Ford GT, Saleen Special Vehicles is capable of producing as many as 15 complete vehicles per day.
Show-Car Facilities.
SSV houses a multitude of specialty facilities configured with a focus upon the creation of vehicles for use in motion pictures and auto shows. SSV offered prototype model and assembly services to other automotive OEM companies.


Preorder economy

A preorder economy is a type of proposed future economy where the exact demand for goods is known ahead of time, before any material production takes place. It has been discussed within the framework of ecological economics.
Just-in-time manufacturing.
Creating a preorder economy has recently been proposed as an economic efficiency solution to the environmental problems facing modern society. These environmental challenges are believed to be caused in part by unsustainable levels of production, consumption and advertising related to the imperfect exchange of information in market economies. Therefore, preorder economy theory advocates using the Internet as the means to coordinate all production with existing consumer desires, so that almost nothing is made which does not have someone ready to buy it. This is the idea of just in time manufacturing taken to its logical end.
References.
Stanley, Conrad. (2006) "The Preorder Economy: Coordinating Supply and Demand on the Way to a Sustainable Future", International Journal of Environment, Workplace and Employment, Vol. 2, Nos. 2/3, pp. 180–205.


TO-220

The TO-220 is a style of electronic package used for high-powered, through-hole components with pin spacing. The "TO" designation stands for "transistor outline". TO-220 packages have three leads. Similar packages with two, four, five or seven leads are also manufactured. A notable characteristic is a metal tab with a hole, used to mount the case to a heatsink, allowing the component to dissipate more heat than one constructed in a TO-92 case. Common TO-220-packaged components include discrete semiconductors such as transistors and silicon-controlled rectifiers, as well as integrated circuits.
Typical applications.
The TO-220 package is a "power package" intended for power semiconductors and an example of a through-hole design rather than a surface-mount technology type of package. TO-220 packages can be mounted to a heat sink to dissipate several watts of waste heat. On a so-called "infinite heat sink", this can be 50 W or more. The top of the package has a metal tab with a hole used to mount the component to a heat sink. Thermal compound is often applied between package and heatsink to further improve heat transfer.
The metal tab is often connected electrically to the internal circuitry. This does not normally pose a problem when using isolated heatsinks, but an electrically-insulating pad or sheet may be required to electrically isolate the component from the heatsink if the heatsink is electrically conductive, grounded or otherwise non-isolated. Many materials may be used to electrically isolate the TO-220 package, some of which have the added benefit of high thermal conductivity.
In applications that require a heatsink, damage or destruction of the TO-220 device due to overheating may occur if the heatsink is dislodged during operation.
A heatsinked TO-220 package dissipating 1 W of heat will have an internal (junction) temperature typically 2 to 5 °C higher than the package's temperature (due to the thermal resistance between the junction and the metal tab), and the metal tab of the TO-220 package will typically have a temperature 1 to 60 °C higher than the ambient temperature, depending on the type of heatsink (if any) used.
The junction-to-case thermal resistance of a TO-220 packaged device (which typically matters less than the case-to-ambient thermal resistance), depends on the thickness and the area of the semiconductor die inside the package, typically in a range between 0.5 °C/W and 3 °C/W (according to one textbook) or 1.5 °C/W and 4 °C/W (according to another).
If more heat needs to be dissipated, devices in the also widely used TO-247 (or TO-3P) package can be selected. TO-3P has a typical junction-to-ambient (heatsink) thermal resistance of only about 40 °C/W, and its TO-3PF variant a slightly lower one. Further increase of heat dissipation capability is possible with power modules.
When a TO-220 package is used without a heatsink, the package acts as its own heatsink, and the heatsink-to-ambient thermal resistance in air for a TO-220 package is approximately 70 °C/W.
Variations.
The TO-220 family of outlines is defined by the JEDEC organization. There are a number of variations on this outline, such as:
Sometimes the designation is followed by the number of leads, as in TO-220AB-5L for five leads, etc.
There also some vendor-specific variations such as International Rectifier's SUPER-220, which dispenses with the hole in favor of clip-mounting, thus claiming TO-247-like thermal performance in a TO-220 footprint.
Common components that use the TO-220 package.
The TO-220 case is found on semiconductor devices handling less than 100 amperes and operating at less than a few hundred volts. These devices operate at DC or relatively low (audio) frequencies, since the TO-220 package is not intended for devices operating at radio frequencies. In addition to bipolar, bipolar Darlington, and power MOSFET transistors, the TO-220 case is also used for fixed and variable linear voltage regulator integrated circuits, and for Schottky diode pairs.


Vendor

In a supply chain, a vendor, supplier, provider or a seller, is an enterprise that contributes goods or services. Generally, a supply chain vendor manufactures inventory/stock items and sells them to the next link in the chain. Today, these terms refer to a supplier of any goods or service.
Description.
A vendor is a supply chain management term that means anyone who provides goods or services of experience to another entity. Vendors may sell B2B (business-to-business; i.e., to other companies), B2C (business to consumers or Direct-to-consumer), or B2G (business to government). Some vendors manufacture inventoriable items and then sell those items to customers, while other vendors offer services or experiences.
The term vendor and the term supplier are often used indifferently. The difference is that the vendors "sells" the goods or services while the supplier "provides" the goods or services. In most of business context, except retail, this difference has no impact and words are interchangeable.
Typically vendors are tracked in either a finance system or a warehouse management system.
Vendors are often managed with a vendor compliance checklist or vendor quality audits, and these activities can be effectively managed by software tools.
Purchase orders are usually used as a contractual agreement with vendors to buy goods or services.
Vendors may or may not function as distributors or manufacturers of goods. If vendors are also manufacturers, they may either build to stock or build to order.
"Vendor" is often a generic term, used for suppliers of industries from retail sales to manufacturers to city organizations. The term generally applies only to the immediate seller, or the organization that is paid for the goods, rather than to the original manufacturer or the organization performing the service if it is different from the immediate supplier.
Types.
There are four basic sorts of vendors in the supply chain, and the companies and business owners play diverse responsibilities.
Manufacturers: A raw material, when transformed into finished goods, is with the help of the manufacturers.
Retailer: A retailer is a reseller who sells things in a store or online, such as apparel, office supplies, street vendors selling hot dogs, and so on.
A Service Provider provides a service, such as maintenance or labour, to customers. Consulting and janitorial services and many other such are two examples.
A Wholesaler sources products from manufacturers and resells them to retail establishments, distributors, and other buyers. They serve as a crucial intermediary in the supply chain, offering competitive pricing and convenient purchasing options.
There must be a vendor relationship with a supplier if a small firm or a major organization wants to resell a product. Vendor registration entails several steps in the process, including completing a credit application, placing a company credit card on file for payments, giving them your company phone number, and establishing payment terms.


Featherboard

A featherboard is a safety device used when working with stationary routers or power saws such as table saws or bandsaws. The purpose of a featherboard is to apply pressure against a workpiece, keeping it flat against a machine table or fence.
Featherboard shapes and sizes vary depending on the tasks for which they are intended. A serviceable featherboard can be shop-fabricated from an approximately 3/4 × 3 × 11 inch piece of straight grained, defect-free wood cut crosswise at a 45-degree angle on one end. Several parallel cuts in the direction of the grain create fingers or "feathers" that flex in the direction of workpiece travel, preventing the workpiece from being dragged backwards by blade friction.
Featherboards are also useful for edge jointing, and making moulding on router tables.


Planning horizon

The planning horizon is the amount of time an organization will look into the future when preparing a strategic plan. Many commercial companies use a five-year planning horizon, however a general Planning horizon is around one year. Other organizations such as the Forestry Commission in the UK have to use a much longer planning horizon to form effective plans.
In manufacturing, a planning horizon is a future time period during which departments that support production will plan production work and determine material requirements.
In economics, a planning horizon is the length of time an individual plans ahead. It's important in the quest for total value, as opposed to short term pleasure consumption.