Cryogenic treatment

A cryogenic treatment is the process of treating workpieces to cryogenic temperatures (typically around -300°F / -184°C, or as low as ) in order to remove residual stresses and improve wear resistance in steels and other metal alloys, such as aluminum. In addition to seeking enhanced stress relief and stabilization, or wear resistance, cryogenic treatment is also sought for its ability to improve corrosion resistance by precipitating micro-fine eta carbides, which can be measured before and after in a part using a quantimet.
The process has a wide range of applications from industrial tooling to the improvement of musical signal transmission. Some of the benefits of cryogenic treatment include longer part life, less failure due to cracking, improved thermal properties, better electrical properties including less electrical resistance, reduced coefficient of friction, less creep and walk, improved flatness, and easier machining.
Processes.
Cryogenic tempering.
Cryogenic tempering is two phase metal treatment that involves a descent and ascent phase, including a cryogenic treatment process (known as "cryogenic processing") where the material is slowly cooled to ultra low temperatures (typically around -300°F / -184°C), which is then optionally reheated slowly (typically up to +325°F / 162°C). Materials do not "harden" during the temperature descent or ascent, rather their molecular structures are compressed together tightly in uniformity through a computer controlled process that typically uses liquid nitrogen to slowly descend temperatures.
Invention History of Cryogenic Processing & Cryogenic Tempering.
The cryogenic treatment process was invented by Ed Busch (CryoTech) in Detroit, Michigan in 1966, inspired by NASA research, which later merged with 300 Below, Inc. in 2000 to become the world's largest and oldest commercial cryogenic processing company after Peter Paulin of Decatur, IL collaborated with process control engineers to invent the world's first computer-controlled "dry" cryogenic processor in 1992 (where he was featured on the Discovery Channel's Next Step TV Show for his invention). Whereas the industry initially submerged metal parts in liquid nitrogen by dunking them or pouring liquid nitrogen over the parts, the earliest results proved inconsistent, which led Mr. Paulin to develop 300 Below's "dry" computer-controlled cryogenic processing equipment to ensure consistent and accurate treatment results across every processing run by introducing liquid nitrogen into a chamber above its boiling point, in a "dry" gaseous state, to ensure that parts in a chamber are not thermally shocked from being exposed to direct liquid contact of ultra low temperatures. A "dry" cryogenic process does not submerge parts in liquid, but rather ensures that temperatures are slowly descended at less than one degree per minute using short bursts of cold gas being introduced via a solenoid-metered pipe, which is controlled by a computer equipment paired with highly accurate RTD (Resistance Temperature Detector) sensors.
Science Behind Dry Cryogenic Processing & Cryogenic Tempering.
Because all changes to metals take place on the quench, the first phase of the initial descent is called cryogenic processing, and by adding a second phase to heat the molecular structure of materials after an initial molecular re-alignment, both processes together are called cryogenic tempering. By using liquid nitrogen, the temperature can go as low as −196 °C, though the typical dwell temperature of cryogenic processing equipment is slightly above the boiling point of liquid nitrogen (closer to -300°F / -184°C) due to being injected into the processing chamber as a gaseous state and making every attempt not to introduce liquid into the chamber that could cause parts to become thermally shocked. Cryogenic processing (and especially cryogenic tempering) can have a profound effect on the mechanical properties of certain materials, such as steels or tungsten carbide, but the heating phase in cryogenic tempering is typically omitted for softer metals like brass in musical instruments, for piano strings, in certain aerospace applications, or for sensitive electronic components like vacuum tubes and transistors in high-end audio equipment. In tungsten carbide (WC-Co), the crystal structure of cobalt is transformed from softer FCC to harder HCP phase whereas the hard tungsten carbide particle is unaffected by the treatment.
Cryogenic machining.
Cryogenic machining is a machining process where the traditional flood lubro-cooling liquid (an emulsion of oil into water) is replaced by a jet of either liquid nitrogen (LN2) or pre-compressed carbon dioxide . Cryogenic machining is useful in rough machining operations, in order to increase the tool life. It can also be useful to preserve the integrity and quality of the machined surfaces in finish machining operations. Cryogenic machining tests have been performed by researchers for several decades, but the actual commercial applications are still limited to very few companies. Both cryogenic machining by turning and milling are possible. Cryogenic machining is a relatively new technique in machining. This concept was applied on various machining processes such as turning, milling, drilling etc. Cryogenic turning technique is generally applied on three major groups of workpiece materials—superalloys, ferrous metals, and viscoelastic polymers/elastomers. The roles of cryogen in machining different materials are unique.
Cryogenic rolling.
Cryogenic rolling or "", is one of the potential techniques to produce nanostructured bulk materials from its bulk counterpart at cryogenic temperatures. It can be defined as rolling that is carried out at cryogenic temperatures. Nanostructured materials are produced chiefly by severe plastic deformation processes. The majority of these methods require large plastic deformations (strains much larger than unity). In case of cryorolling, the deformation in the strain hardened metals is preserved as a result of the suppression of the dynamic recovery. Hence large strains can be maintained and after subsequent annealing, ultra-fine-grained structure can be produced.
Advantages.
Comparison of cryorolling and rolling at room temperature:
Cryogenic treatment in specific materials.
Stainless steel.
The torsional and tensional deformation under cryogenic temperature of stainless steel is found to be significantly enhance the mechanical strength while incorporating the gradual phase transformation inside the steel. This strength improvement is the result of following phenomenon.
Copper.
Zhang et al. exploited the cryorolling to the dynamic plastic deformed copper at liquid nitrogen temperature (LNT-DPD) to greatly enhance tensile strength with high ductility. The key of this combined approach (Cryogenic hardening and Cryogenic rolling) is to engineer the nano-sized twin boundary embedded in the copper.
Processing with the plastic deformation of grained bulk metal decreases the size of the grain boundary and enhances the grain boundary strengthening. However, as the grain gets smaller, the interaction between grain and the dislocation inside impedes further process of grains. Among the grain boundaries, it is known that the twin boundaries, a special type of low-energy grain boundary has lower interaction energy with dislocation leading to much smaller saturation size of the grain.
The cryogenic dynamic plastic deformation creates higher fraction of the twin boundaries compared to the severe plastic deformation. Following cryorolling further reduces the grain boundary energy with relieving the twin boundary leading to higher Hall-Petch strengthening effect. In addition, this increases the ability of grain boundary to accommodate more dislocation leading to the improvement in ductility from cryorolling.
Titanium.
Cryogenic hardening of Titanium is hard to manipulate compare to other face centered cubic (fcc) metals because these hexagonal close packed (hcp) metals has less symmetry and slip systems to exploit. Recently Zhao et al. introduced the efficient method to manipulate nanotwinned titanium which has higher strength, ductility and thermal stability. By cryoforging repetitively along the three principal axes in liquid nitrogen and following annealing process, pure Titanium can possess hierarchical twin boundary network structure which suppresses the motion of dislocation and significantly enhances its mechanical property. The microstructure analysis found that the repeated twinning and de-twinning keep increasing the fraction of nanosized twin boundaries and refining the grains to render much higher Hall-Petch strengthening effect even after the saturation of microscale twin boundary at high flow stress. Especially, the strength and ductility of nanotwinned titanium at 77 K, reaches about 2 GPa, and ~100% which far outweighs those of conventional cryogenic steels even without any inclusion of alloying.


Ball grid array

A ball grid array (BGA) is a type of surface-mount packaging (a chip carrier) used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. The whole bottom surface of the device can be used, instead of just the perimeter. The traces connecting the package's leads to the wires or balls which connect the die to package are also on average shorter than with a perimeter-only type, leading to better performance at high speeds.
BGAs were introduced in the 1990s and became popular by 2001.
Soldering of BGA devices requires precise control and is usually done by automated processes such as in computer-controlled automatic reflow ovens.
Description.
The BGA is descended from the pin grid array (PGA), which is a package with one face covered (or partly covered) with pins in a grid pattern which, in operation, conduct electrical signals between the integrated circuit and the printed circuit board (PCB) on which it is placed. In a BGA the pins are replaced by pads on the bottom of the package, each initially with a tiny solder ball stuck to it. These solder spheres can be placed manually or by automated equipment, and are held in place with a tacky flux. The device is placed on a PCB with copper pads in a pattern that matches the solder balls. The assembly is then heated, either in a reflow oven or by an infrared heater, melting the balls. Surface tension causes the molten solder to hold the package in alignment with the circuit board, at the correct separation distance, while the solder cools and solidifies, forming soldered connections between the device and the PCB.
In more advanced technologies, solder balls may be used on both the PCB and the package. Also, in stacked multi-chip modules, (package on package) solder balls are used to connect two packages.
Advantages.
High density.
The BGA is a solution to the problem of producing a miniature package for an integrated circuit with many hundreds of pins. Pin grid arrays and dual-in-line surface mount (SOIC) packages were being produced with more and more pins, and with decreasing spacing between the pins, but this was causing difficulties for the soldering process. As package pins got closer together, the danger of accidentally bridging adjacent pins with solder grew.
Heat conduction.
A further advantage of BGA packages over packages with discrete leads (i.e. packages with legs) is the lower thermal resistance between the package and the PCB. This allows heat generated by the integrated circuit inside the package to flow more easily to the PCB, preventing the chip from overheating.
Low-inductance leads.
The shorter an electrical conductor, the lower its unwanted inductance, a property which causes unwanted distortion of signals in high-speed electronic circuits. BGAs, with their very short distance between the package and the PCB, have low lead inductances, giving them superior electrical performance to pinned devices.
Disadvantages.
Lack of compliance.
A disadvantage of BGAs is that the solder balls cannot flex in the way that longer leads can, so they are not mechanically compliant. As with all surface mount devices, bending due to a difference in coefficient of thermal expansion between PCB substrate and BGA (thermal stress) or flexing and vibration (mechanical stress) can cause the solder joints to fracture.
Thermal expansion issues can be overcome by matching the mechanical and thermal characteristics of the PCB to those of the package. Typically, plastic BGA devices more closely match PCB thermal characteristics than ceramic devices.
The predominant use of RoHS compliant lead-free solder alloy assemblies has presented some further challenges to BGAs including "head in pillow" soldering phenomenon, "pad cratering" problems as well as their decreased reliability versus lead-based solder BGAs in extreme operating conditions such as high temperature, high thermal shock and high gravitational force environments, in part due to lower ductility of RoHS-compliant solders.
Mechanical stress issues can be overcome by bonding the devices to the board through a process called "underfilling", which injects an epoxy mixture under the device after it is soldered to the PCB, effectively gluing the BGA device to the PCB. There are several types of underfill materials in use with differing properties relative to workability and thermal transfer. An additional advantage of underfill is that it limits tin whisker growth.
Another solution to non-compliant connections is to put a "compliant layer" in the package that allows the balls to physically move in relation to the package. This technique has become standard for packaging DRAMs in BGA packages.
Other techniques for increasing the board-level reliability of packages include use of low-expansion PCBs for ceramic BGA (CBGA) packages, interposers between the package and PCB, and re-packaging a device.
Difficulty of inspection.
Once the package is soldered into place, it is difficult to find soldering faults. X-ray machines, industrial CT scanning machines, special microscopes, and endoscopes to look underneath the soldered package have been developed to overcome this problem. If a BGA is found to be badly soldered, it can be removed in a "rework station", which is a jig fitted with infrared lamp (or hot air), a thermocouple and a vacuum device for lifting the package. The BGA can be replaced with a new one, or it can be refurbished (or "reballed") and re-installed on the circuit board. Pre-configured solder balls matching the array pattern can be used to reball BGAs when only one or a few need to be reworked. For higher volume and repeated lab work, a stencil-configured vacuum-head pick-up and placement of loose spheres can be used.
Due to the cost of visual X-ray BGA inspection, electrical testing is very often used instead. Very common is boundary scan testing using an IEEE 1149.1 JTAG port.
A cheaper and easier inspection method, albeit destructive, is becoming increasingly popular because it does not require special equipment. Commonly referred to as dye and pry, the process includes immersing the entire PCB or just the BGA attached module into a dye, and after drying, the module is pried off and the broken joins are inspected. If a solder location contains the dye, then it indicates that the connection was imperfect.
Difficulties during circuit development.
During development it is not practical to solder BGAs into place, and sockets are used instead, but tend to be unreliable. There are two common types of socket: the more reliable type has spring pins that push up under the balls, although it does not allow using BGAs with the balls removed as the spring pins may be too short.
The less reliable type is a ZIF socket, with spring pinchers that grab the balls. This does not work well, especially if the balls are small.
Cost of equipment.
Expensive equipment is required to reliably solder BGA packages; hand-soldering BGA packages is very difficult and unreliable, usable only for the smallest packages in the smallest quantities. However, as more ICs have become available only in leadless (e.g. quad-flat no-leads package) or BGA packages, various DIY reflow methods have been developed using inexpensive heat sources such as heat guns, and domestic toaster ovens and electric skillets.
Variants.
Effectively also the flip chip methods for mounting chip dies to a carrier is sort of a BGA design derivate with the functional equivalent of the balls there being called bumps or micro bumps. This is realized at an already microscopic size level.
To make it easier to use ball grid array devices, most BGA packages only have balls in the outer rings of the package,
leaving the innermost square empty.
Intel used a package designated BGA1 for their Pentium II and early Celeron mobile processors. BGA2 is Intel's package for their Pentium III and some later Celeron mobile processors. BGA2 is also known as FCBGA-479. It replaced its predecessor, BGA1.
For example, the "micro-FCBGA" (flip chip ball grid array) is Intel's current BGA mounting method for mobile processors that use a flip chip binding technology. It was introduced with the "Coppermine" Mobile Celeron. Micro-FCBGA has 479 balls that are 0.78 mm in diameter. The processor is affixed to the motherboard by soldering the balls to the motherboard. This is thinner than a pin grid array socket arrangement, but is not removable.
The 479 balls of the Micro-FCBGA package (a package almost identical to the 478-pin socketable micro-FCPGA package) are arranged as the 6 outer rings of a 1.27 mm pitch (20 balls per inch pitch) 26x26 square grid, with the inner 14x14 region empty.
Procurement.
Primary end-users of BGAs are original equipment manufacturers (OEMs). There is also a market among electronic hobbyists do it yourself (DIY) such as the increasingly popular maker movement. While OEMs generally source their components from the manufacturer, or the manufacturer's distributor, the hobbyist will typically obtain BGAs on the aftermarket through electronic component brokers or .


Surface-mount technology

Surface-mount technology (SMT), originally called planar mounting, is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). An electrical component mounted in this manner is referred to as a surface-mount device (SMD). In industry, this approach has largely replaced the through-hole technology construction method of fitting components, in large part because SMT allows for increased manufacturing automation which reduces cost and improves quality. It also allows for more components to fit on a given area of substrate. Both technologies can be used on the same board, with the through-hole technology often used for components not suitable for surface mounting such as large transformers and heat-sinked power semiconductors.
An SMT component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of solder balls (BGAs), or terminations on the body of the component.
History.
Surface-mount technology was developed in the 1960s. By 1986 surface mounted components accounted for 10% of the market at most, but was rapidly gaining popularity. By the late 1990s, the great majority of high-tech electronic printed circuit assemblies were dominated by surface mount devices. Much of the pioneering work in this technology was done by IBM. The design approach first demonstrated by IBM in 1960 in a small-scale computer was later applied in the Launch Vehicle Digital Computer used in the Instrument Unit that guided all Saturn IB and Saturn V vehicles. Components were mechanically redesigned to have small metal tabs or end caps that could be directly soldered to the surface of the PCB. Components became much smaller and component placement on both sides of a board became far more common with surface mounting than through-hole mounting, allowing much higher circuit densities and smaller circuit boards and, in turn, machines or subassemblies containing the boards.
Often the surface tension of the solder is enough to hold the parts to the board; in rare cases parts on the bottom or "second" side of the board may be secured with a dot of adhesive to keep components from dropping off inside reflow ovens if the part is above the limit of 30g per square inch of pad area. Adhesive is sometimes used to hold SMT components on the bottom side of a board if a wave soldering process is used to solder both SMT and through-hole components simultaneously. Alternatively, SMT and through-hole components can be soldered on the same side of a board without adhesive if the SMT parts are first reflow-soldered, then a selective solder mask is used to prevent the solder holding those parts in place from reflowing and the parts floating away during wave soldering. Surface mounting lends itself well to a high degree of automation, reducing labor cost and greatly increasing production rates.
Conversely, SMT does not lend itself well to manual or low-automation fabrication, which is more economical and faster for one-off prototyping and small-scale production, and this is one reason why many through-hole components are still manufactured. Some SMDs can be soldered with a temperature-controlled manual soldering iron, but unfortunately, those that are very small or have too fine a lead pitch are impossible to manually solder without expensive hot-air solder reflow equipment. SMDs can be one-quarter to one-tenth the size and weight, and one-half to one-quarter the cost of equivalent through-hole parts, but on the other hand, the costs of a certain SMT part and of an equivalent through-hole part may be quite similar, though rarely is the SMT part more expensive.
Common abbreviations.
Different terms describe the components, technique, and machines used in manufacturing. These terms are listed in the following table:
Assembly techniques.
Where components are to be placed, the printed circuit board normally has flat, usually tin-lead, silver, or gold plated copper pads without holes, called "solder pads". Solder paste, a sticky mixture of flux and tiny solder particles, is first applied to all the solder pads with a stainless steel or nickel stencil using a screen printing process. It can also be applied by a jet-printing mechanism, similar to an inkjet printer. After pasting, the boards proceed to the pick-and-place machines, where they are placed on a conveyor belt. The components to be placed on the boards are usually delivered to the production line in either paper/plastic tapes wound on reels or plastic tubes. Some large integrated circuits are delivered in static-free trays. Numerical control pick-and-place machines remove the parts from the tapes, tubes or trays and place them on the PCB.
The boards are then conveyed into the reflow soldering oven. They first enter a pre-heat zone, where the temperature of the board and all the components is gradually, uniformly raised to prevent thermal shock. The boards then enter a zone where the temperature is high enough to melt the solder particles in the solder paste, bonding the component leads to the pads on the circuit board. The surface tension of the molten solder helps keep the components in place, and if the solder pad geometries are correctly designed, surface tension automatically aligns the components on their pads.
There are a number of "techniques" for reflowing solder. One is to use infrared lamps; this is called infrared reflow. Another is to use a hot gas convection. Another technology which is becoming popular again is special fluorocarbon liquids with high boiling points which use a method called vapor phase reflow. Due to environmental concerns, this method was falling out of favor until lead-free legislation was introduced which requires tighter controls on soldering. At the end of 2008, convection soldering was the most popular reflow technology using either standard air or nitrogen gas. Each method has its advantages and disadvantages. With infrared reflow, the board designer must lay the board out so that short components do not fall into the shadows of tall components. Component location is less restricted if the designer knows that vapor phase reflow or convection soldering will be used in production. Following reflow soldering, certain irregular or heat-sensitive components may be installed and soldered by hand, or in large-scale automation, by focused infrared beam (FIB) or localized convection equipment.
If the circuit board is double-sided then this printing, placement, reflow process may be repeated using either solder paste or glue to hold the components in place. If a wave soldering process is used, then the parts must be glued to the board prior to processing to prevent them from floating off when the solder paste holding them in place is melted.
After soldering, the boards may be washed to remove flux residues and any stray solder balls that could short out closely spaced component leads. Rosin flux is removed with fluorocarbon solvents, high flash point hydrocarbon solvents, or low flash solvents e.g. limonene (derived from orange peels) which require extra rinsing or drying cycles. Water-soluble fluxes are removed with deionized water and detergent, followed by an air blast to quickly remove residual water. However, most electronic assemblies are made using a "No-Clean" process where the flux residues are designed to be left on the circuit board, since they are considered harmless. This saves the cost of cleaning, speeds up the manufacturing process, and reduces waste. However, it is generally suggested to wash the assembly, even when a "No-Clean" process is used, when the application uses very high frequency clock signals (in excess of 1 GHz). Another reason to remove no-clean residues is to improve adhesion of conformal coatings and underfill materials. Regardless of cleaning or not those PCBs, current industry trend suggests to carefully review a PCB assembly process where "No-Clean" is applied, since flux residues trapped under components and RF shields may affect surface insulation resistance (SIR), especially on high component density boards.
Certain manufacturing standards, such as those written by the IPC - Association Connecting Electronics Industries require cleaning regardless of the solder flux type used to ensure a thoroughly clean board. Proper cleaning removes all traces of solder flux, as well as dirt and other contaminants that may be invisible to the naked eye. No-Clean or other soldering processes may leave "white residues" that, according to IPC, are acceptable "provided that these residues have been qualified and documented as benign". However, while shops conforming to IPC standard are expected to adhere to the Association's rules on board condition, not all manufacturing facilities apply IPC standard, nor are they required to do so. Additionally, in some applications, such as low-end electronics, such stringent manufacturing methods are excessive both in expense and time required.
Finally, the boards are visually inspected for missing or misaligned components and solder bridging. If needed, they are sent to a rework station where a human operator repairs any errors. They are then usually sent to the testing stations (in-circuit testing and/or functional testing) to verify that they operate correctly.
Automated optical inspection (AOI) systems are commonly used in PCB manufacturing. This technology has proven highly efficient for process improvements and quality achievements.
Advantages.
The main advantages of SMT over the older through-hole technique are:
Rework.
Defective surface-mount components can be repaired by using soldering irons (for some connections), or using a non-contact rework system. In most cases a rework system is the better choice because SMD work with a soldering iron requires considerable skill and is not always feasible.
Reworking usually corrects some type of error, either human- or machine-generated, and includes the following steps:
Sometimes hundreds or thousands of the same part need to be repaired. Such errors, if due to assembly, are often caught during the process. However, a whole new level of rework arises when component failure is discovered too late, and perhaps unnoticed until the end user of the device being manufactured experiences it. Rework can also be used if products of sufficient value to justify it require revision or re-engineering, perhaps to change a single firmware-based component. Reworking in large volume requires an operation designed for that purpose.
There are essentially two non-contact soldering/desoldering methods: infrared soldering and soldering with hot gas.
Infrared.
With infrared soldering, the energy for heating up the solder joint is transmitted by long-, medium- or short-wave infrared electromagnetic radiation.
Advantages:
Disadvantages:
Hot gas.
During hot gas soldering, the energy for heating up the solder joint is transmitted by a hot gas. This can be air or inert gas (nitrogen).
Advantages:
Disadvantages:
Hybrid technology.
Hybrid rework systems combine medium-wave infrared radiation with hot air
Advantages:
Disadvantages
Packages.
Surface-mount components are usually smaller than their counterparts with leads, and are designed to be handled by machines rather than by humans. The electronics industry has standardized package shapes and sizes (the leading standardisation body is JEDEC).


Pin grid array

A pin grid array (PGA) is a type of integrated circuit packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a regular array on the underside of the package. The pins are commonly spaced 2.54 mm (0.1") apart, and may or may not cover the entire underside of the package.
PGAs are often mounted on printed circuit boards using the through hole method or inserted into a socket. PGAs allow for more pins per integrated circuit than older packages, such as dual in-line package (DIP).
Chip mounting.
The chip can be mounted either on the top or the bottom (the pinned side). Connections can be made either by wire bonding or through flip chip mounting. Typically, PGA packages use wire bonding when the chip is mounted on the pinned side, and flip chip construction when the chip is on the top side. Some PGA packages contain multiple dies, for example Zen 2 and Zen 3 Ryzen CPUs for the AM4 socket.
Flip chip.
A flip-chip pin grid array (FC-PGA or FCPGA) is a form of pin grid array in which the die faces downwards on the top of the substrate with the back of the die exposed. This allows the die to have a more direct contact with the heatsink or other cooling mechanism.
The FC-PGA was introduced by Intel with the Coppermine core Pentium III and Celeron processors based on Socket 370, and was later used for Socket 478-based Pentium 4 and Celeron processors. FC-PGA processors fit into zero insertion force (ZIF) Socket 370 and Socket 478-based motherboard sockets; similar packages have also been used by AMD. It is still used today for mobile Intel processors.
Material.
Ceramic.
A ceramic pin grid array (CPGA) is a type of packaging used by integrated circuits. This type of packaging uses a ceramic substrate with pins arranged in a pin grid array. Some CPUs that use CPGA packaging are the AMD Socket A Athlons and the Duron.
A CPGA was used by AMD for Athlon and Duron processors based on Socket A, as well as some AMD processors based on Socket AM2 and Socket AM2+. While similar form factors have been used by other manufacturers, they are not officially referred to as CPGA. This type of packaging uses a ceramic substrate with pins arranged in an array.
Organic.
An organic pin grid array (OPGA) is a type of connection for integrated circuits, and especially CPUs, where the silicon die is attached to a plate made out of an organic plastic which is pierced by an array of pins which make the requisite connections to the socket.
Plastic.
Plastic pin grid array (PPGA) packaging was used by Intel for late-model Mendocino core Celeron processors based on Socket 370. Some pre-Socket 8 processors also used a similar form factor, although they were not officially referred to as PPGA.
Pin layout.
Staggered pin.
The staggered pin grid array (SPGA) is used by Intel processors based on Socket 5 and Socket 7. Socket 8 used a partial SPGA layout on half the processor.
It consists of two square arrays of pins, offset in both directions by half the minimum distance between pins in one of the arrays. Put differently: within a square boundary the pins form a diagonal square lattice. There is generally a section in the center of the package without any pins. SPGA packages are usually used by devices that require a higher pin density than what a PGA can provide, such as microprocessors.
Stud.
A stud grid array (SGA) is a short-pinned pin grid array chip scale package for use in surface-mount technology. The polymer stud grid array or plastic stud grid array was developed jointly by the Interuniversity Microelectronics Centre (IMEC) and Laboratory for Production Technology, Siemens AG.
rPGA.
The reduced pin grid array was used by the socketed mobile variants of Intel's Core i3/5/7 processors and features a reduced pin pitch of 1mm, as opposed to the 1.27mm pin pitch used by contemporary AMD processors and older Intel processors. It is used in the G1, G2, and G3 sockets.


Zig-zag in-line package

The zig-zag in-line package (ZIP) is a packaging technology for integrated circuits. It was intended as a replacement for dual in-line packaging (DIL or DIP). A ZIP is an integrated circuit encapsulated in a slab of plastic with 16, 20, 28 or 40 pins, measuring (for the ZIP-20 package) about 3 mm x 30 mm x 10 mm. The package's pins protrude in two rows from one of the long edges. The two rows are staggered by 1.27 mm (0.05"), giving them a zig-zag appearance, and allowing them to be spaced more closely than a rectangular grid would allow. The pins are inserted into holes in a printed circuit board, with the packages standing at right-angles to the board, allowing them to be placed closer together than DIPs of the same size. ZIPs have now been superseded by surface-mount packages such as the thin small-outline packages (TSOPs), but are still in use. The quad in-line package uses a similar staggered semiconductor package design.
High-power devices (such as high-voltage op-amp ICs, voltage regulators, and motor driver ICs) are still being manufactured in a package with a zig-zag pinout (and normally screwed onto a heatsink). These zig-zag packages include variations on the TO220 such as "TO220S", "staggered leads TO-220-11", "staggered leads TO-220-15", and HZIP. The trademarks Pentawatt or Hexawatt are also used for chips in multi-leaded power packages like TDA2002/2003/2020/2030 and L200.
As for computers, dynamic RAM ZIP chips are now only to be found in obsolete computers, some of these are:


Model maker

A Model maker is a professional Craftsperson who creates a three-dimensional representation of a design or concept. Most products in use and in development today first take form as a model. This "model" may be an exacting duplicate (prototype) of the future design or a simple mock-up of the general shape or concept. Many prototype models are used for testing physical properties of the design, others for usability and marketing studies.
Mock-ups are generally used as part of the design process to help convey each new iteration. Some model makers specialize in "scale models" that allow an easier grasp of the whole design or for portability of the model to a trade show or an architect or client's office. Other scale models are used in museum displays and in the movie special effects industry. Model makers work in many environments from private studio/shops to corporate design and engineering facilities to research laboratories.
The model maker must be highly skilled in the use of many machines, such as manual lathes, manual mills, Computer Numeric Control (CNC) machines, lasers, wire EDM, water jet saws, tig welders, sheet metal fabrication tools and wood working tools. Fabrication processes model makers take part in are powder coating, shearing, punching, plating, folding, forming and anodizing. Some model makers also use increasingly automated processes, for example cutting parts directly with digital data from computer-aided design plans on a CNC mill or creating the parts through rapid prototyping. Hand tools used by a model maker are an exacto knife, tweezers, sprue cutter, tape, glue, paint, and paint brushes.
There are two basic processes used by the model maker to create models: additive and subtractive. Additive can be as simple as adding clay to create a form, sculpting and smoothing to the final shape. Body fillers, foam and resins are also used in the same manner. Most rapid prototyping technologies are based on the additive process, solidifying thin layered sections or slices one on top of each other. Subtractive is like whittling a solid block of wood or chiseling stone to the desired form. Most milling and other machining methods are subtractive, progressively using smaller and finer tools to remove material from the rough shape to get to the level of detail needed in the final model.
Model makers may use a combination of these methods and technologies to create the model in the most expeditious manner. The parts are usually test fitted, then sanded and painted to represent the intended finish or look. Model makers are required to recreate many faux finishes like brick, stone, grass, molded plastic textures, glass, skin and even water.


Abrasive flow machining

Abrasive flow machining (AFM), also known as abrasive flow deburring or extrude honing, is an interior surface finishing process characterized by flowing an abrasive-laden fluid through a workpiece. This fluid is typically very viscous, having the consistency of putty, or dough. AFM smooths and finishes rough surfaces, and is specifically used to remove burrs, polish surfaces, form radii, and even remove material. The nature of AFM makes it ideal for interior surfaces, slots, holes, cavities, and other areas that may be difficult to reach with other polishing or grinding processes. Due to its low material removal rate, AFM is not typically used for large stock-removal operations, although it can be.
Abrasive flow machining was first patented by the Extrude Hone Corporation in 1970.
Process.
In abrasive flow machining, the abrasive fluid flows through the workpiece, effectively performing erosion. Abrasive particles in the fluid contact raised features on the surface of the workpiece and remove them. The fluid is forced through the workpiece by a hydraulic ram, where it acts as a flexible file, or slug, molding itself precisely to the shape of the workpiece. The highest amount of material removal occurs in areas where the flow of the fluid is restricted; according to Bernoulli's Principle, the flow speed and pressure of the fluid decrease in these areas, facilitating a higher material removal rate (MRR). The pressure exerted by the fluid on all contacting surfaces also results in a very uniform finish.
AFM may be performed once, as a one-way flow process, or repeatedly as a two-way flow process. In the two-way flow process, a reservoir of medium exists at either end of the workpiece, and the medium flows back and forth through the workpiece from reservoir to reservoir.
Equipment.
An abrasive flow machine normally includes two medium chambers equipped with hydraulic rams, a fixture for holding the workpiece, and a clamping system that holds all the components tightly together. Most machines allow for the loading of different types of abrasive medium, and include the capacity to adjust the pressure used in extruding the medium through the workpiece. They may be manually operated, or automated using CNC. For machines designed to accommodate high production volumes, accessories such as part-cleaning stations, unloading and reloading stations, media refeed devices, and media heat exchangers may be included.


Tardiness (scheduling)

In scheduling, tardiness is a measure of a delay in executing certain operations and earliness is a measure of finishing operations before due time. The operations may depend on each other and on the availability of equipment to perform them.
Typical examples include job scheduling in manufacturing and data delivery scheduling in data processing networks.
In manufacturing environment, inventory management considers both tardiness and earliness undesirable. Tardiness involves backlog issues such as customer compensation for delays and loss of goodwill. Earliness incurs expenses for storage of the manufactured items and ties up capital.
Mathematical formulations.
In an environment with multiple jobs, let the deadline be formula_1 and the completion time be formula_2 of job formula_3. Then for job formula_3
In scheduling common objective functions are formula_8 or weighted version of these sums, formula_9, where every job comes with a weight formula_10. The weight is a representation of job cost, priority, etc.
In a large number of cases the problems of optimizing these functions are NP-hard.


Metal stitching

Metal stitching is an industrial technique for repairing cracked and broken cast iron, steel, bronze or aluminium structures and their components. The process is carried out cold, without welding. It allows the repair of cast iron and cast steel, often in-situ, without the distortion from welding, and can be used in other situations where heat cannot be used to achieve a repair.
Background.
The metal stitching process was developed in the late 1930s as an option for repairing cast iron components and equipment on the Texas oil fields. The process was developed to provide a permanent, stress-free repair and utilized when the use of heat or open flame was limited or not allowed. Four men have been credited with the development of this new metal locking technique: Lawrence B. Scott, Fred Lewis, Earl Reynolds and Hal W. Harman. However, it was Hal Harman who initially invented the metal stitching technique, and he filed for a patent to the technique in the 7th of August, 1937.
In 1938 L.B. Scott was officially credited with the invention of the Metalock variation of metal stitching, whilst he was still working for Harman. Scott was given patent rights to the repair technique and materials used. Scott used his patents to secure the repair process, called it the ‘Metalock Repair Process’, and began to offer franchises under the Metalock Corporation trade name after starting his own operation in Long Island City, NY. Shortly thereafter, Thomas O. Oliver Ltd. (based in Ontario, Canada) was the first company to purchase a franchise.
Fred Lewis (a partner in the development process) purchased a franchise and began operation in Chicago, IL in 1942. The same year, George Jackman Sr. left T.O. Oliver Ltd. and formed Metal Locking Service, Inc. as a stand-alone company.
Hal Harman took forward his method - called Chainlock. Initially Harman and Scott both offered competing metal stitching repairs. Then, for several years, Harman and Scott proceeded to take each other to court, to contest patent infringements and design rights. Ultimately Harman succeeded and Scott had to concede the process ownership to others.
The first repairs, in the 1930s, were in hazardous oilfields. Just prior to and during WWII, the process was used secretly on US Naval vessels, the process becoming a standard repair method approved by the US Navy after the war. It was in this time period that the process was verified as a credible alternative to welding.
Over the years alternative variations of the metal stitching processes were developed, they use terms like Metal Stitch, and Metal Locking, and Metalock to describe their repair process. Lock-N-Stitch is a slightly different stitching method, that was developed from the original stitching concept, by Gary J Reed.
Development of the process.
Major Edward Peckham, a Canadian engineer originally of the Canadian army, was so impressed by what he saw in Texas that he brought the metalock process to Europe, and in 1947 opened an office in London, England. Peckham registered the Metalock Casting Repair Service, which became Metalock (Britain) Ltd. In 1953, to coordinate the expansion of the new process, the Metalock International Association was started in London. An engineering standard was developed to ensure the best possible outcome for a metalock repair.
During the early years, from the 1953 to the 1970s, research was applied to improve the process in Sweden, Germany and the UK. This resulted in improvement in two main areas; the creation of a material for the key that was designed for maximum strength under operating conditions. And the development of the key design and dimensions, and how to locate the keys in as best layout possible.
During the mid 20th century, the process gained rapid popularity among engineers and in manufacturing. The evidence of this is in the publications of specialist engineering publications
Process description.
The metalock process consists of a series of steps, that uses metal alloy ‘locks’ or 'keys' that are inserted into the cast iron across and at right angles to the fracture. The process is applied to a fracture, or to a complete break in the material. There is often related damage caused in the break, that has to be cut out prior to repair.
The steps in the process are:
Once complete, the appearance this repair gives is one of a 'stitch' from the sewing of cloth, hence the common term 'metal stitching.’ This method has also been called ‘metal locking’ as it locks in the broken parts of the machine. The durability of the repair is normally high as the technician ensures that the repair maximises the original equipment strength design pattern.
Applications.
As a cold repair process, metal stitching is applicable where heat should not be used, and in situations where the material cannot be successfully repaired by welding.
Situations where application of heat would be problematic are particularly appropriate for cold metal stitching, examples include: oil installations and engine rooms. Often large equipment cannot be easily dismantled and removed for repairs, the metalock repair process can often be performed in-situ with little or no dismantling. It is this feature that created the foundation for the development of the process. More unusual onsite locations expanded to include the repair of ship propellers whilst they are fixed to the ship, large mining equipment that is located underground, and underwater repairs.
Welding introduces thermal stresses into the base metal, and also changes the grain structure of the metal crystals - altering the characteristics and the strength of that part of the equipment. Heat also distorts the alignment of the original surface. Once the equipment is machined and returned to use, the parent metal is always significantly weaker. Often, the site of the original repair then subsequently fails.
The metal stitching repair process however tends to maintain alignment of original surfaces, since the lack of heat during the repair produces no distortion of the completed repair. In addition, the parent metal is not weakened due to material changes. Metal stitching dampens and absorbs compression stresses; providing a good ‘expansion joint’ for castings subject to thermal stresses. It distributes the tensional load away from fatigue points and maintains relieved conditions of inherent internal stresses where the rupture initially occurred. Where the repair involved a pressurized interface, the repair process has the ability to seal the join.


Cyber manufacturing

Cyber manufacturing is a concept derived from cyber-physical systems (CPS) that refers to a modern manufacturing system that offers an information-transparent environment to facilitate asset management, provide reconfigurability, and maintain productivity. Compared with conventional experience-based management systems, cyber manufacturing provides an evidence-based environment to keep equipment users aware of networked asset status, and transfer raw data into possible risks and actionable information. Driving technologies include design of cyber-physical systems, combination of engineering domain knowledge and computer sciences, as well as information technologies. Among them, mobile applications for manufacturing is an area of specific interest to industries and academia.
Motivation.
The idea of cyber manufacturing originates from the fact that Internet-enabled services have added business value in economic sectors such as retail, music, consumer products, transportation, and healthcare; however, compared to existing Internet-enabled sectors, manufacturing assets are less connected and less accessible in real-time. Besides, current manufacturing enterprises make decisions following a top-down approach: from overall equipment effectiveness to assignment of production requirements, without considering the condition of machines. This usually leads to inconsistency in operation management due to lack of linkage between factories, possible overstock in spare part inventory, as well as unexpected machine downtime. Such situation calls for connectivity between machines as a foundation, and analytics on top of that as a necessity to translate raw data into information that actually facilitates user decision making. Expected functionalities of cyber manufacturing systems include machine connectivity and data acquisition, machine health prognostics, fleet-based asset management, and manufacturing reconfigurability.
Technology.
Several technologies are involved in developing cyber-manufacturing solutions. The following is a short description of these technologies and their involvement in cyber-manufacturing.
Development.
In 2013 the Office of Naval Research in the US Military has issued a proposal solicitation subjected for cyber-manufacturing.


Ti-6Al-2Sn-4Zr-2Mo

Ti-6Al-2Sn-4Zr-2Mo (UNS designation R54620), also known as Ti 6-2-4-2, is a near alpha titanium alloy known for its high strength and excellent corrosion resistance. It is often used in the aerospace industry for creating high-temperature jet engines and the automotive industry to create high performance automotive valves.


Automation technician

Automation technicians repair and maintain the computer-controlled systems and robotic devices used within industrial and commercial facilities to reduce human intervention and maximize efficiency. Their duties require knowledge of electronics, mechanics and computers. Automation technicians perform routine diagnostic checks on automated systems, monitor automated systems, isolate problems and perform repairs. If a problem occurs, the technician needs to be able to troubleshoot the issue and determine if the problem is mechanical, electrical or from the computer systems controlling the process. Once the issue has been diagnosed, the technician must repair or replace any necessary components, such as a sensor or electrical wiring. In addition to troubleshooting, Automation technicians design and service control systems ranging from electromechanical devices and systems to high-speed robotics and programmable logic controllers (PLCs). These types of systems include robotic assembly devices, conveyors, batch mixers, electrical distribution systems, and building automation systems. These machines and systems are often found within industrial and manufacturing plants, such as food processing facilities. Alternate job titles include field technician, bench technician, robotics technician, PLC technician, production support technician and maintenance technician.
Education and training.
Automation technician programs integrate computer programming with mechanics, electronics and process controls, They also commonly include coursework in hydraulics, pneumatics, programmable logic controllers, electrical circuits, electrical machinery and human-machine interfaces. Typical courses include math, communications, circuits, digital devices and electrical controls. Other courses include robotics, automation, electrical motor controls, programmable logic controllers, and computer-aided design. Good math and analytic skills are essential to understand automated systems and isolate problems. In addition to programming, Automation Technicians are expected to become proficient with various instruments and hand tools for troubleshooting, such as electrical multimeters, signal analyzers, and frequency counters.
Employers generally prefer applicants who have completed an automation technician certificate or associate degree. These programs can be completed at colleges and universities in either an in-class or online format. Some colleges, such as George Brown College, offer an online automation technician program that uses simulation software, LogixSim, to complete automation lab projects and assignments.
Other relevant credentials to become an automation technician include mechatronics, robotics, and PLCs. Up-to-date credentials and certifications can enhance employment opportunities and keep technicians current with the latest technological developments. In addition to colleges and universities, other organizations and companies also offer credential programs in automation, including equipment manufacturers such as Rockwell and professional associations, such as the Electronics Technicians Association, Robotics Industries Association and the Manufacturing Skill Standards Council.
Career prospects.
Career opportunities for automation technicians include a wide range of manufacturing and service industries such as automotive, pharmaceutical, power distribution, food processing, mining, and transportation. Other career prospects include areas as machine assembly, troubleshooting and testing, systems integration, application support, maintenance, component testing and assembly, automation programming, robot maintenance and programming, technical sales and services.
Typical job-related activities may involve:
Experienced automation technicians with advanced training may become specialists or troubleshooters who help other technicians diagnose difficult problems, or work with engineers in designing equipment and developing maintenance procedures. Automation technicians with leadership ability also may eventually become maintenance supervisors or service managers. Due to the highly specialized skills and knowledge required, there are many opportunities available to automation technicians in the service sector where there is a great demand for contract and sub-contract work with smaller manufacturing and distribution companies. Some experienced automation technicians open their own design, installation and maintenance companies. They can also become wholesalers or retailers of automation equipment, including inside and outside sales of automation equipment and systems.
Because of their familiarity with control systems and equipment, automation technicians are particularly well qualified to become manufacturers' sales representatives. Other related opportunities include customer service, quality-control, quality-assurance and consulting.


Design for availability

Design for Availability is the design process for a system targeting availability of the system for guarantying readiness as the major part of goal specification. This design is generally used toward availability based contracts. Design for availability means that design process should start by given parameters of requirement space and maps them to design parameter space. However, the conventional trial and error of parameters set followed by sensitivity analysis might end to the same result area in the design plane.
Description.
The design parameters generally include reliability, maintainability of the system. Reliability will be the result of manufacturing of the system where as maintainability is coming from operational, maintenance logistics, inventory management, Prognostic Health Management (PHM) and supply chain design of the services that system require. The general usage of this philosophy of system design is geared toward outcome-based contracts. Availability is the major factor of operational effectiveness along with performance of the system. Availability based contracts are not as complicated as performance based contract because the discussion over metrics and requirement is less obscure to define for customer and designer. Minimum required availability of complex system is a key factor of many distributed and repairable systems like ATM network or Airliner.
In Availability-based Contracts instead of parts, supplier is paid for a guaranteed level of services and performance a and system capability, like availability-based tariff for electric power. The supplier often has to guarantee the availability and preparedness of system at lesser costs by considering the logistics as part of design. The contractor will also have more control over logistics and supply chain of system. The key point of using availability instead of Performance is that combining availability of different part of one platform or system from its subsets is feasible and easy unlike dealing with obscure measures of performance in Performance based logistics.
Recent interest in availability contracts that specify a required availability has created an interest in deriving system design and support parameters directly from an availability-based contracts. But, a point to point allocation from parameter of operation and support to meet availability requirement in the performance space, given the required availability distribution is a direct way of design which must be followed by a sensitivity analysis and robustness of parameters. However, determining design parameters from an availability requirement is a stochastic reverse design problem.
Evaluating an availability requirement is a challenge for manufacturers and supporters of systems because determining how to deliver a specific availability is not trivial. The required availability can be defined over the instance of system or over the fleet. It can be defined over different time windows or in different geographical boxes. However availability optimization approaches provide solutions only at selected points in time (not all times), using mean time to failure (or fixed rate demand) and mean time to repair as deterministic values as part of convex optimization.
Availability engineering in network world is generally toward reducing unplanned downtime or planned downtime by providing redundancy or fast switching systems. This area of design is the subject of different discipline with different approach. The main difference between network industry and manufacturing availability is that former is more targeting toward decreasing downtime where as in reliability world it might be seen as using higher reliability part in a cost-effective manner.


Thin small outline package

Thin small outline package (TSOP) is a type of surface mount IC package. They are very low-profile (about 1mm) and have tight lead spacing (as low as 0.5mm).
They are frequently used for RAM or Flash memory ICs due to their high pin count and small volume. In some applications, they are being supplanted by ball grid array packages which can achieve even higher densities. The prime application for this technology is memory. SRAM, flash memory, FSRAM and E2PROM manufacturers find this package well suited to their end-use products. It answers the needs required by telecom, cellular, memory modules, PC cards (PCMCIA cards), wireless, netbooks and countless other product applications.
TSOP is the smallest leaded form factor for flash memory.
History.
The TSOP package was developed to fit the reduced package height available in a PCMCIA PC Card.
Physical properties.
TSOPs are rectangular in shape and come in two varieties: Type I and Type II. Type I ICs have the pins on the shorter side and Type II have the pins on the longer side. The table below shows basic measurements for common TSOP packages.
HTSOP.
HTSOP (Heatsink TSOP) is a variant of TSOP with an exposed pad on the bottom side. The pad is soldered to the PCB to transfer heat from the package to the PCB.
Similar packages.
There are a variety of small form-factor IC carrier available other than TSOPs


Residual stress

In materials science and solid mechanics, residual stresses are stresses that remain in a solid material after the original cause of the stresses has been removed. Residual stress may be desirable or undesirable. For example, laser peening imparts deep beneficial compressive residual stresses into metal components such as turbine engine fan blades, and it is used in toughened glass to allow for large, thin, crack- and scratch-resistant glass displays on smartphones. However, unintended residual stress in a designed structure may cause it to fail prematurely.
Residual stresses can result from a variety of mechanisms including inelastic (plastic) deformations, temperature gradients (during thermal cycle) or structural changes (phase transformation). Heat from welding may cause localized expansion, which is taken up during welding by either the molten metal or the placement of parts being welded. When the finished weldment cools, some areas cool and contract more than others, leaving residual stresses. Another example occurs during semiconductor fabrication and microsystem fabrication when thin film materials with different thermal and crystalline properties are deposited sequentially under different process conditions. The stress variation through a stack of thin film materials can be very complex and can vary between compressive and tensile stresses from layer to layer.
Applications.
While uncontrolled residual stresses are undesirable, some designs rely on them. In particular, brittle materials can be toughened by including compressive residual stress, as in the case for toughened glass and pre-stressed concrete. The predominant mechanism for failure in brittle materials is brittle fracture, which begins with initial crack formation. When an external tensile stress is applied to the material, the crack tips concentrate stress, increasing the local tensile stresses experienced at the crack tips to a greater extent than the average stress on the bulk material. This causes the initial crack to enlarge quickly (propagate) as the surrounding material is overwhelmed by the stress concentration, leading to fracture.
A material having compressive residual stress helps to prevent brittle fracture because the initial crack is formed under compressive (negative tensile) stress. To cause brittle fracture by crack propagation of the initial crack, the external tensile stress must overcome the compressive residual stress before the crack tips experience sufficient tensile stress to propagate.
The manufacture of some swords utilises a gradient in martensite formation to produce particularly hard edges (notably the katana). The difference in residual stress between the harder cutting edge and the softer back of the sword gives such swords their characteristic curve.
In toughened glass, compressive stresses are induced on the surface of the glass, balanced by tensile stresses in the body of the glass. Due to the residual compressive stress on the surface, toughened glass is more resistant to cracks, but shatter into small shards when the outer surface is broken. A demonstration of the effect is shown by Prince Rupert's Drop, a material-science novelty in which a molten glass globule is quenched in water: Because the outer surface cools and solidifies first, when the volume cools and solidifies, it "wants" to take up a smaller volume than the outer "skin" has already defined; this puts much of the volume in tension, pulling the "skin" in, putting the "skin" in compression. As a result, the solid globule is extremely tough, able to be hit with a hammer, but if its long tail is broken, the balance of forces is upset, causing the entire piece to shatter violently.
In certain types of gun barrels made with two tubes forced together, the inner tube is compressed while the outer tube stretches, preventing cracks from opening in the rifling when the gun is fired.
Compressive residual stress.
Common methods to induce compressive residual stress are shot peening for surfaces and High frequency impact treatment for weld toes. Depth of compressive residual stress varies depending on the method. Both methods can increase lifetime of constructions significantly.
Creation of residual stress.
There are some techniques which are used to create uniform residual stress in a beam. For example, the four point bend allows inserting residual stress by applying a load on a beam using two cylinders.
Measurement techniques.
Overview.
There are many techniques used to measure residual stresses, which are broadly categorised into destructive, semi-destructive and non-destructive techniques. The selection of the technique depends on the information required and the nature of the measurement specimen. Factors include the depth/penetration of the measurement (surface or through-thickness), the length scale to be measured over (macroscopic, mesoscopic or microscopic), the resolution of the information required, and also the composition geometry and location of the specimen. Additionally, some of the techniques need to be performed in specialised laboratory facilities, meaning that "on-site" measurements are not possible for all of the techniques.
Destructive techniques.
Destructive techniques result in large and irreparable structural change to the specimen, meaning that either the specimen cannot be returned to service or a mock-up or spare must be used. These techniques function using a "strain release" principle; cutting the measurement specimen to relax the residual stresses and then measuring the deformed shape. As these deformations are usually elastic, there is an exploitable linear relationship between the magnitude of the deformation and magnitude of the released residual stress. Destructive techniques include:
Semi-destructive techniques.
Similarly to the destructive techniques, these also function using the "strain release" principle. However, they remove only a small amount of material, leaving the overall integrity of the structure intact. These include:
Non-destructive techniques.
The non-destructive techniques measure the effects of relationships between the residual stresses and their action of crystallographic properties of the measured material. Some of these work by measuring the diffraction of high frequency electromagnetic radiation through the atomic lattice spacing (which has been deformed due to the stress) relative to a stress-free sample. The Ultrasonic and Magnetic techniques exploit the acoustic and ferromagnetic properties of materials to perform relative measurements of residual stress. Non-destructive techniques include:
Relief of residual stress.
When undesired residual stress is present from prior metalworking operations, the amount of residual stress may be reduced using several methods. These methods may be classified into thermal and mechanical (or nonthermal) methods. All the methods involve processing the part to be stress relieved as a whole.
Thermal method.
The thermal method involves changing the temperature of the entire part uniformly, either through heating or cooling. When parts are heated for stress relief, the process may also be known as stress relief bake. Cooling parts for stress relief is known as cryogenic stress relief and is relatively uncommon.
Stress relief bake.
Most metals, when heated, experience a reduction in yield strength. If the material's yield strength is sufficiently lowered by heating, locations within the material that experienced residual stresses greater than the yield strength (in the heated state) would yield or deform. This leaves the material with residual stresses that are at most as high as the yield strength of the material in its heated state.
Stress relief bake should not be confused with annealing or tempering, which are heat treatments to increase ductility of a metal. Although those processes also involve heating the material to high temperatures and reduce residual stresses, they also involve a change in metallurgical properties, which may be undesired.
For certain materials such as low alloy steel, care must be taken during stress relief bake so as not to exceed the temperature at which the material achieves maximum hardness (See Tempering in alloy steels).
Cryogenic stress relief.
Cryogenic stress relief involves placing the material (usually steel) into a cryogenic environment such as liquid nitrogen. In this process, the material to be stress relieved will be cooled to a cryogenic temperature for a long period, then slowly brought back to room temperature.
Nonthermal methods.
Mechanical methods to relieve undesirable surface tensile stresses and replace them with beneficial compressive residual stresses include shot peening and laser peening. Each works the surface of the material with a media: shot peening typically uses a metal or glass material; laser peening uses high intensity beams of light to induce a shock wave that propagates deep into the material.


Lawler's algorithm

Lawler's algorithm is a powerful technique for solving a variety of constrained scheduling problems. particularly single-machine scheduling. The algorithm handles any precedence constraints. It schedules a set of simultaneously arriving tasks on one processor with precedence constraints to minimize maximum tardiness or lateness. Precedence constraints occur when certain jobs must be completed before other jobs can be started.
Objective functions.
The objective function is assumed to be in the form formula_1, where formula_2 is any nondecreasing function and formula_3 is the flow time. When formula_4, the objective function corresponds to minimizing the maximum lateness, where formula_5 is due time for job formula_6 and formula_7 lateness of job formula_6. Another expression is formula_9, which corresponds to minimizing the maximum tardiness.
Algorithm.
The algorithm builds the schedule back to front. For each scheduling step, it looks only at the tasks that no other tasks depend on, and puts the one with the latest due date at the end of the schedule queue. Then it repeats this process until all jobs are scheduled.
The algorithm works by planning the job with the least impact as late as possible. Starting at formula_10 that formula_11 is the production time of job formula_12.
 formula_13 set of already scheduled jobs (at start: S = formula_14)
 formula_15 set of jobs whose successors have been scheduled (at start: all jobs without successors)
 formula_16 time when the next job will be completed (at start: formula_10)
 whileformula_18 do
 select formula_19 such that formula_20
 schedule formula_12 such that it completes at time formula_16
 add formula_12 to formula_13, delete formula_12 from formula_15 and update formula_15.
 formula_28
 end while
Example 1.
Assuming there are three jobs: t1, t2, and t3, with the following precedence constraints:
And the following deadlines (due date in a month)
Now we construct the required set of jobs:
Repeat the following steps until J is empty:
Do the next round:
Do the next round:
J is now empty. The end.
Example 2.
A more complex example, with simplified steps:
The jobs and precedence constraints are shown below: a parent node --> child node in the tree.
The due dates of jobs are shown underneath of each node of the tree in parentheses.
Now look at the set of jobs without any successors, find the one with latest due date, put it into the front of S:


This article details the 2010–11 UEFA Europa League qualifying phase and play-off round.
Each tie was played over two legs, with each team playing one leg at home. The team that had the higher aggregate score over the two legs progressed to the next round. In the event that aggregate scores finished level, the away goals rule was applied; i.e., the team that scored more goals away from home over the two legs progressed. If away goals were also equal, then 30 minutes of extra time was played, divided into two 15-minute halves. The away goals rule was again applied after extra time; i.e., if there were goals scored during extra time and the aggregate score was still level, the visiting team qualified by virtue of more away goals scored. If no goals were scored during extra time, the tie was decided by a penalty shootout.
"All times are CEST (UTC+2)"
Round and draw dates.
All draws were held at UEFA headquarters in Nyon, Switzerland.
Matches may also be played on Tuesdays or Wednesdays instead of the regular Thursdays due to scheduling conflicts.
Teams.
Below are the 160 teams involved in the qualifying phase and play-off round, grouped by their starting rounds. The 37 winners of the play-off round qualified for the group stage to join the 10 losing teams from the Champions League play-off round, and the title holders, Atlético Madrid.
In each round, teams were seeded based on their 2010 UEFA club coefficients. Prior to the draw, UEFA may form "groups" in accordance with the principles set by the Club Competitions Committee, but they are purely for convenience of the draw and do not resemble any real groupings in the sense of the competition, while ensuring that teams from the same association not drawn against each other.
CL-c Losing teams from the Champions League third qualifying round (Champions Path)
CL-n Losing teams from the Champions League third qualifying round (Non-Champions Path)
First qualifying round.
Matches.
Second leg.
"Anorthosis won 4–0 on aggregate."
"Tauras Tauragė won 5–4 on aggregate."
"Qarabağ won 5–2 on aggregate."
"Mogren won 5–0 on aggregate."
"Šibenik won 3–0 on aggregate."
"Dinamo Tbilisi won 2–1 on aggregate."
"1–1 on aggregate. Olimpia won on away goals."
"Bnei Yehuda won 1–0 on aggregate."
"Portadown won 2–1 on aggregate."
"MYPA won 7–0 on aggregate."
"Dnepr Mogilev won 8–2 on aggregate."
"Randers won 7–3 on aggregate."
"1–1 on aggregate. Dacia won on away goals."
"Győri ETO won 5–3 on aggregate."
"KF Tirana won 1–0 on aggregate."
"Gefle won 4–1 on aggregate."
"Rabotnički won 11–0 on aggregate."
"TPS won 7–1 on aggregate."
"Zrinjski won 4–2 on aggregate."
"Dundalk won 5–4 on aggregate."
"Kalmar FF won 4–0 on aggregate."
"Široki Brijeg won 5–0 on aggregate."
"Zestafoni won 5–0 on aggregate."
"KR Reykjavík won 5–2 on aggregate."
"Ruch Chorzów won 3–1 on aggregate."
"Torpedo Zhodino won 6–1 on aggregate."
Second qualifying round.
Matches.
Second leg.
"Rabotnički won 1–0 on aggregate."
"Teteks won 3–1 on aggregate."
"OFK Beograd won 3–2 on aggregate."
"Zestafoni won 3–1 on aggregate."
"Maccabi Tel Aviv won 3–2 on aggregate."
"Spartak Zlatibor Voda won 5–3 on aggregate."
"Qarabağ won 3–2 on aggregate."
"2–2 on aggregate. Cercle Brugge won on away goals."
"3–3 on aggregate. Dnepr Mogilev won on away goals."
"Austria Wien won 3–2 on aggregate."
"2–2 on aggregate. Molde won on away goals."
"Baník Ostrava won 6–0 on aggregate."
"Dinamo Minsk won 10–1 on aggregate."
"Karpaty Lviv won 6–2 on aggregate."
"Kalmar FF won 2–0 on aggregate."
Replay:
"MYPA won 8–0 on aggregate."
"Dinamo Tbilisi won 4–2 on aggregate."
"Randers won 4–1 on aggregate."
"Elfsborg won 3–1 on aggregate."
"APOEL won 6–1 on aggregate."
"Utrecht won 5–1 on aggregate."
"Shamrock Rovers won 2–1 on aggregate."
"Dinamo București won 7–1 on aggregate."
"Anorthosis won 3–2 on aggregate."
"Wisła won 7–0 on aggregate."
"Brøndby won 3–0 on aggregate."
"Levski Sofia won 8–0 on aggregate."
"Beşiktaş won 7–0 on aggregate."
"1–1 on aggregate. Ruch won on away goals."
"Rapid Wien won 6–2 on aggregate."
"Maribor won 3–1 on aggregate."
"Bangor City won 3–2 on aggregate."
"Győri ETO won 5–0 on aggregate."
"Zrinjski won 13–3 on aggregate."
"Olympiacos won 11–1 on aggregate."
"Lausanne-Sport won 2–1 on aggregate."
"Marítimo won 6–4 on aggregate."
"Cliftonville won 1–0 on aggregate."
"Budućnost Podgorica won 4–2 on aggregate."
"Motherwell won 2–0 on aggregate."
Third qualifying round.
Matches.
Second leg.
"Rapid Wien won 4–1 on aggregate."
"Elfsborg won 7–1 on aggregate."
"Galatasaray won 7–3 on aggregate."
"Dnepr Mogilev won 3–1 on aggregate."
"Karpaty Lviv won 2–0 on aggregate."
"Qarabağ won 4–2 on aggregate."
"Dinamo Minsk won 3–2 on aggregate."
"Sturm Graz won 3–1 on aggregate."
"Anorthosis won 3–2 on aggregate."
"2–2 on aggregate. Sibir Novosibirsk won on away goals."
"AZ won 2–1 on aggregate."
"Dnipro Dnipropetrovsk won 3–2 on aggregate."
"Timișoara won 5–4 on aggregate."
"Brøndby won 3–1 on aggregate."
"Lausanne-Sport won 4–3 on aggregate."
"Utrecht won 4–1 on aggregate."
"Levski Sofia won 6–3 on aggregate."
"Aris won 4–3 on aggregate."
"Genk won 8–3 on aggregate."
"Beşiktaş won 4–1 on aggregate."
"2–2 on aggregate. Maccabi Tel Aviv won on away goals."
"APOEL won 4–1 on aggregate."
"Marítimo won 10–3 on aggregate."
"Slovan Bratislava won 3–2 on aggregate."
"Austria Wien won 6–1 on aggregate."
"Stuttgart won 5–4 on aggregate."
"Hajduk Split won 4–3 on aggregate."
"Liverpool won 4–0 on aggregate."
"CSKA Sofia won 5–1 on aggregate."
"Juventus won 3–0 on aggregate."
"Maribor won 6–2 on aggregate."
"1–1 on aggregate. Győri ETO won 4–3 on penalties."
"Motherwell won 4–1 on aggregate."
"Odense won 5–3 on aggregate."
"Sporting won 3–1 on aggregate."


Ion milling machine

Ion milling machine thins samples until they are transparent to electrons by firing ions (typically argon) at the surface from an angle and sputtering material from the surface. By making a sample electron transparent, it can be imaged and characterized in a transmission electron microscope (TEM). Ion beam milling may also be used for cross-section polishing prior to SEM analysis of materials that are difficult to prepare using mechanical polishing.


Advances in Production Engineering & Management (APEM) is an interdisciplinary refereed journal. It is published quarterly by Production Engineering Institute (PEI), an organisational unit of the Faculty of mechanical engineering at the University of Maribor. The main goal of journal is to present high quality research developments in all areas of production engineering and production management, as well as their applications in industry and services, to a broad audience of academics and practitioners. Like most scientific journals, it can be obtained in print or in electronic form.
Advances in Production Engineering & Management is abstracted and indexed in the world’s leading bibliographic databases, including Web of Science (Science Citation Index Expanded – SCIE, Journal Citation Reports – JCR, and Current Contents – CC), Scopus, Inspec, EBSCO, and ProQuest.
In the Web of Science (THOMSON REUTERS) bibliographic database the journal is included into two categories:
1. Engineering, Manufacturing;
2. Material Science, Multidisciplinary.
The journal Advances in Production Engineering & Management has received its first impact factor calculated by Thomson Reuters in June 2016. The current impact factor is 1.125 (Journal Citation Reports 2016, year 2015).


Volvo Concept Coupe

The Volvo Concept Coupe is a concept car that was first revealed at the 2013 Frankfurt Motor Show. The concept car was based on Volvo's new platform Scalable Product Architecture (SPA), designed to provide the technical foundation for future Volvo models.
The front wheels are driven by a four-cylinder, two-litre petrol engine from Volvo's Volvo Engine Architecture (VEA) engine family, fed by both turbocharger and supercharger. The rear wheels are driven by an electric motor, making this car a plug in hybrid.
The engines have a combined peak power of and maximum torque of . The car was designed by Volvo's head of design Thomas Ingenlath, taking inspiration from the Volvo P1800 of the 1960s. Volvo Cars' subsidiary, Polestar, put the car into production, and re-badged it as the Polestar 1.


Product flow diagram

The product flow diagram (PFD) is a representation of the order by which a sequence of products is created according to product-based planning principles. It is related to the product breakdown structure (PBS).
The product flow diagram is a prescribed activity of the PRINCE2 project management methodology which mandates the use of product-based planning.
Features.
Some important features of the product flow diagram (PFD) include:
The product flow diagram is typically created iteratively with product descriptions and the product breakdown structure because as a project manager works through the logic they will identify missing products and additional information about products.


List of bottling companies

This is a list of bottling companies. A bottling company is a commercial enterprise whose output is the bottling of beverages for distribution. A bottler is a company which mixes drink ingredients and fills up cans and bottles with the drink. The bottler then distributes the final product to wholesale sellers in a geographic area. Large companies like The Coca-Cola Company and Dannizota sell their product to bottlers such as the Coca-Cola Bottling Co., who then bottle and distribute it.
M.


CMF design

Color, Materials, Finish (CMF) is an area of industrial design that focuses on the chromatic, tactile and decorative identity of products and environments.
Characteristics.
CMF design uses metadesign logic, the simultaneous planning of the identity of entire ranges of products for a given brand. This makes it possible, for example, to adopt a single color matrix, instead of using a series of separate and different color cards for each line of products, as previously done. A contribution to the development of this approach to design was the impetus provided by the proliferation in the 1980s of complete ranges of new systemic products.
Brand products are often thought up by different designers who through the use of ad-hoc CMF design manuals can work together to ensure a unique but coordinated identity for the products. This working process is advantageous in terms of the choice of color base for systemic products that are either of heterogeneous origin or are considered OEM products. The latter, even if characterized by different forms, can be connoted with the base colors or materials that are representative of the brand due to CMF design. Since CMF design manuals and the color matrix have a prescriptive role, the designers who create them are rarely involved in the applicative distribution either of colors, materials or finishes of individual products.


Kanto Auto Works

 was a Japanese car manufacturer. It was a member of the Toyota Group. In July 2012, Kanto Auto Works and two other Toyota subsidiaries were merged to form Toyota Motor East Japan.
History.
In April 1946, Kanto Auto Works was established in Yokosuka, Kanagawa Prefecture, Japan, as an independent company called "Kanto Electric Motor Works" which focused on repairing cars, assembling electric vehicles and producing bus bodies. In early 1948, it became a Toyota contractor, producing auto bodies. During its early years, the company also assembled some cars for Toyota (Toyota SB, Toyota Master, Toyota Crown). The company also diversified into other products such as yachts and prefabricated homes. In 1950, it adopted the "Kanto Auto Works" name. In 1960, the company became a permanent car assembler through a new Yokosuka plant. Later, the company replaced Yokosuka for car assembly with the Higashi-Fuji (established in 1968) and Iwate (established in 1993) plants.
Kanto Auto Works was a public company until the 2011 Tohoku earthquake, Toyota announced it would make it a wholly owned subsidiary. On July 1, 2012, Kanto Auto Works and two other Toyota subsidiaries (Central Motors and Toyota Motors Tohoku) were combined into a single company called Toyota Motor East Japan, Inc.


Thick-film technology

Thick-film technology is used to produce electronic devices/modules such as surface mount devices modules, hybrid integrated circuits, heating elements, integrated passive devices and sensors. Main manufacturing technique is screen printing (stenciling), which in addition to use in manufacturing electronic devices can also be used for various graphic reproduction targets. It became one of the key manufacturing/miniaturisation techniques of electronic devices/modules during 1950s. Typical film thickness – manufactured with thick film manufacturing processes for electronic devices – is 0.0001 to 0.1 mm.
Thick-film circuits/modules are widely used in the automotive industry, both in sensors, e.g. mixture of fuel/air, pressure sensors, engine and gearbox controls, sensor for releasing airbags, ignitors to airbags; common is that high reliability is required, often extended temperature range also along massive thermocycling of circuits without failure. Other application areas are space electronics, consumer electronics, and various measurement systems where low cost and/or high reliability is needed.
The simplest form to utilise a thick film technology is a module substrate/board, where wiring is manufactured using thick film process. Additionally resistors and large tolerance capacitors can be manufactured with thick film methods. Thick film wiring can be made compatible with surface-mount technology (SMT), and if needed (due to tolerances and/or size requirements) surface-mountable parts (resistors, capacitors, ICs, etc.) can be assembled on a thick film substrate.
The manufacturing of thick film devices/modules is an additive process involving deposition of several (typically max 6–8) successive layers of conductive, resistive and dielectric layers onto an electrically insulating substrate using a screen-printing process.
As a low cost manufacturing method it is applicable to produce large volumes of discrete passive devices like resistors, thermistors, varistors and integrated passive devices.
Thick film technology is also one of the alternatives to be used in hybrid integrated circuits and competes and complements typically in electronics miniaturization (parts or elements/area or volume) with SMT based on PCB (printed circuit board)/PWB (printed wiring board) and thin film technology.
Steps.
A typical thick-film process would consist of the following stages:
Lasering of substrates.
Typically thick film circuit substrates are Al2O3/alumina, beryllium oxide (BeO), aluminum nitride (AlN), stainless steel, sometimes even some polymers and in rare cases even silicon (Si) coated with silicon dioxide (SiO2)., Commonly used substrates for thick-film processes are 94 or 96% alumina. Alumina is very hard and lasering of the material is the most efficient way to machine it. The thick-film process is also a means of miniaturization, where one substrate normally contains many units (final circuits). With lasering it is possible to scribe, profile and drill holes. Scribing is a process where a line of laser pulses is fired into the material and 30–50% of the material is removed; this weakens the substrate, and after all other processes are completed the substrate can easily be divided into single units.
Profiling is, for example, used a lot in sensor fabrication, where a circuit needs to fit round tubes or other different complex shapes.
Drilling of holes can provide a "via" (conductive link) between the two sides of the substrate, normally hole sizes are in the range 0.15–0.2 mm.
Lasering before processing the substrates has a cost advantage to lasering or dicing using a diamond saw after processing.
Ink preparation.
Inks for electrodes, terminals, resistors, dielectric layers etc. are commonly prepared by mixing the metal or ceramic powders required with a solvent (ceramic thick film pastes) or polymer pastes to produce a paste for screen-printing. To achieve a homogeneous ink the mixed components of the ink may be passed through a three-roll mill. Alternatively, ready-made inks may be obtained from several companies offering products for the thick-film technologist.
Screen-printing and its improvements.
Screen-printing is the process of transferring an ink through a patterned woven mesh screen or stencil using a squeegee.
For improving accuracy, increasing integration density and improving line and space accuracy of traditional screen-printing photoimageable thick-film technology has been developed. Use of these materials however changes typically the process flow and needs different manufacturing tools.
Drying/Curing.
After allowing time after printing for settling of the ink, each layer of ink that is deposited is usually dried at a moderately high temperature of to evaporate the liquid component of the ink and fix the layer temporarily in position on the substrate so that it can be handled or stored before final processing. For inks based on polymers and some solder pastes that cure at these temperatures, this may be the final step that is required. Some inks also require curing by exposure to UV light.
Firing.
For many of the metal, ceramic and glass inks used in thick film processes a high temperature (usually greater than 300 °C) firing is required to fix the layers in position permanently on the substrate.
Abrasive Trimming of resistors.
After firing the resistors can be trimmed using a precision abrasive cutting method first developed by S.S. White. The method involves a fine abrasive media, usually 0.027 mm aluminum oxide. The abrasive cutting is fed through a carbide nozzle tip that can be of different sizes. The nozzle is advanced through the fired resistor while the resistor element is monitored with probe contacts and when final value is reached the abrasive blast is shut off and the nozzle retracts to the zero start position. The abrasive technique can achieve very high tolerances with no heat and no cracking of the glass frit used in the ink formulation.
Laser trimming of resistors.
After firing, the substrate resistors are trimmed to the correct value. This process is named laser trimming. Many chip resistors are made using thick-film technology. Large substrates are printed with resistors fired, divided into small chips and these are then terminated, so they can be soldered on the PCB board. With laser trimming two modes are used; either passive trimming, where each resistor is trimmed to a specific value and tolerance, or active trimming, where the feedback is used to adjust to a specific voltage, frequency or response by laser trimming the resistors on the circuit while powered up.
Mounting of capacitors and semiconductors.
The development of the SMT process actually evolves from the thick film process. Also mounting of naked dies (the actual silicon chip without encapsulation) and wire bonding is a standard process, this provides the basis for miniaturization of the circuits as all the extra encapsulation is not necessary.
Separation of elements.
This step is often necessary because many components are produced on one substrate at the same time. Thus, some means of separating the components from each other is required. This step may be achieved by wafer dicing.
Integration of devices.
At this stage, the devices may require integrating with other electronic components, usually in the form of a printed circuit board. This may be achieved by wire bonding or soldering.
Process control of thick film manufacturing.
There are numerous steps in the thick film manufacturing, which need careful control like roughness of the substrate, curing temperatures and times of pastes, selected stencil thickness vs. paste type etc., Therefore number of used pastes and process steps define the complexity of the process and cost of the final product.
Designing circuits based on thick-film technology.
Same or similar electronic design automation tools which are used for designing printed circuit boards can be used for designing thick film circuits. However, the compatibility of tooling formats with stencil manufacturing/manufacturer needs attention as well as the availability of the geometrical, electrical and thermal design rules for simulation and layout design from the final manufacturer.


EE Technologies

Electronic Evolution Technologies, Inc. (also referred to as EE Technologies, Inc or EET) is a multi-national electronic manufacturing services (EMS) company headquartered in Reno, Nevada. EET provides full electronic and mechanical box build assembly services and also specializes in circuit board assembly for a variety of markets, including the automotive, medical, military and digital audio/video markets. The company operates a global manufacturing network with operations in the Americas and Mexico, providing services to original equipment manufacturers (OEMs). EET has been recognized as one of the top 20 contract manufacturers in the western United States.
History.
EE Technologies, Inc. was incorporated as Meridian Electronics in 1994. By 1999 Meridian Electronics had grown to $28 million a year in revenue. EE Technologies was spun off from Meridian Electronics in March 2000. In October 2000, the company moved into a new facility in South Reno, Nevada. In December 2002, the company expanded their facilities by allowing for improved production efficiencies and capabilities, as well as improved inventory management. Currently, the company employs over 180 people with facilities in the US and Mexico. EE Technologies, Inc recently settled a lawsuit with the Environmental Protection Agency for $80,000 over them failing to file required reports on toxic chemicals.
Operations.
EE Technologies, Inc's manufacturing network comprises locations in the Americas and Mexico. The company's services include design, engineering, manufacturing and systems assembly, fulfilment and after-market services.
Mexico Facility.
In October 2005, EE Technologies, Inc expanded further with the opening of a facility in Empalme, Sonora, Mexico. The equipment, process, and training in the Mexico facility mirror the operations in Reno, Nevada. Both facilities are ISO/TS 16949:2002 certified.