Junk box

Junk box is a term used by amateur radio operators (hams) to describe a collection of spare parts and old equipment kept to assist in building and repairing their station. Typical items found in a junk box are electronic components such as resistors and capacitors as well as small parts such as screws, nuts and bolts. A junk box may also contain surplus, cast off or used electronic gear. Radio amateurs who construct their own equipment, known as homebrewers, often have large or well stocked junk boxes.
Description and uses.
According to some hams, a well-stocked junk box is a requirement for anyone who likes to build, repair, or tinker with radio equipment and electronic gear. Keeping an ample supply of spare electronic components provides the ham with parts to build a variety of electronic projects, as well as "spares" of components needed for repairs. Resistors, capacitors, transistors, meters, speakers, wire, cable, and even small mechanical parts such as screws, nuts and bolts are typical junk box items. Cannibalizing or removing parts from old equipment is sometimes the only way for an individual to obtain some types of parts, either because they are no longer made, or can only be ordered in large quantities. Cast-off or used electronic equipment make especially good additions to a junk box. What non-hams may see as junk, hams often see as treasure. Hamfests, surplus stores, electronic swapmeets and even dumpster diving are often venues for hams to trade, buy, scrounge, or salvage spare parts and components. Junk boxes can range in size from small cardboard or plastic boxes, to large collections that fill garages and outbuildings. Many hams derive satisfaction from having an especially large junk box full of exotic and hard-to-find components. Others feel that the act of tracking down parts is half the fun.
Use in homebrewing.
Homebrewing is a slang term in amateur radio referring to building an alternative to a commercially available piece of equipment or accessory by hand. "Homebrewers" often naturally maintain a sizeable junk box, and amateur radio publications have often employed the term in DIY project articles such as "The 'Junker' Amplifier" from QST, Oct 1970, an RF amplifier built from scrounged and junk-box parts.


Flat no-leads package

Flat no-leads packages such as quad-flat no-leads (QFN) and dual-flat no-leads (DFN) physically and electrically connect integrated circuits to printed circuit boards. Flat no-leads, also known as micro leadframe (MLF) and SON (small-outline no leads), is a surface-mount technology, one of several package technologies that connect ICs to the "surfaces" of PCBs without through-holes. Flat no-lead is a near chip scale plastic encapsulated package made with a planar copper lead frame substrate. Perimeter lands on the package bottom provide electrical connections to the PCB. Flat no-lead packages usually, but not always, include an exposed thermally conductive pad to improve heat transfer out of the IC (into the PCB). Heat transfer can be further facilitated by metal vias in the thermal pad. The QFN package is similar to the quad-flat package (QFP), and a ball grid array (BGA).
Flat no-lead cross-section.
The figure shows the cross section of a flat no-lead package with a lead frame and wire bonding. There are two types of body designs, "punch singulation" and "saw singulation". Saw singulation cuts a large set of packages in parts. In punch singulation, a single package is moulded into shape. The cross section shows a saw-singulated body with an attached thermal head pad. The lead frame is made of copper alloy and a thermally conductive adhesive is used for attaching the silicon die to the thermal pad. The silicon die is electrically connected to the lead frame by 1–2 thou diameter gold wires.
The pads of a saw-singulated package can either be completely under the package, or they can fold around the edge of the package.
Different types.
Two types of QFN packages are common: air-cavity QFNs, with an air cavity designed into the package, and plastic-moulded QFNs with air in the package minimized.
Less-expensive plastic-moulded QFNs are usually limited to applications up to ~2–3 GHz. It is usually composed of just 2 parts, a plastic compound and copper lead frame, and does not come with a lid.
In contrast, the air-cavity QFN is usually made up of three parts; a copper leadframe, plastic-moulded body (open, and not sealed), and either a ceramic or plastic lid. It is usually more expensive due to its construction, and can be used for microwave applications up to 20–25 GHz.
QFN packages can have a single row of contacts or a double row of contacts.
Advantages.
This package offers a variety of benefits including reduced lead inductance, a small sized "near chip scale" footprint, thin profile and low weight. It also uses perimeter I/O pads to ease PCB trace routing, and the exposed copper die-pad technology offers good thermal and electrical performance. These features make the QFN an ideal choice for many new applications where size, weight, thermal and electrical performance are important.
Design, manufacturing, and reliability challenges.
Improved packaging technologies and component miniaturization can often lead to new or unexpected design, manufacturing, and reliability issues. This has been the case with QFN packages, especially when it comes to adoption by new non-consumer electronic OEMs.
Design and manufacturing.
Some key QFN design considerations are pad and stencil design. When it comes to bond pad design two approaches can be taken: solder mask defined (SMD) or non-solder mask defined (NSMD). A NSMD approach typically leads to more reliable joints, since the solder is able to bond to both the top and sides of the copper pad. The copper etching process also generally has tighter control than the solder masking process, resulting in more consistent joints. This does have the potential to affect the thermal and electrical performance of the joints, so it can be helpful to consult the package manufacturer for optimal performance parameters. SMD pads can be used to reduce the chances of solder bridging, however this may affect overall reliability of the joints. Stencil design is another key parameter in QFN design process. Proper aperture design and stencil thickness can help produce more consistent joints (i.e. minimal voiding, outgassing, and floating parts) with proper thickness, leading to improved reliability.
There are also issues on the manufacturing side. For larger QFN components, moisture absorption during solder reflow can be a concern. If there is a large amount of moisture absorption into the package then heating during reflow can lead to excessive component warpage. This often results in the corners of the component lifting off the printed circuit board, causing improper joint formation. To reduce the risk of warpage issues during reflow a moisture sensitivity level of 3 or higher is recommended.
Several other issues with QFN manufacturing include: part floating due to excessive solder paste under the center thermal pad, large solder voiding, poor reworkable characteristics, and optimization of the solder reflow profile.
Reliability.
Component packaging is often driven by the consumer electronics market with less consideration given to higher reliability industries such as automotive and aviation. It can therefore be challenging to integrate component package families, such as the QFN, into high reliability environments. QFN components are known to be susceptible to solder fatigue issues, especially thermomechanical fatigue due to thermal cycling. The significantly lower standoff in QFN packages can lead to higher thermomechanical strains due to coefficient of thermal expansion (CTE) mismatch as compared to leaded packages. For example, under accelerated thermal cycling conditions between -40 °C to 125 °C, various quad flat package (QFP) components can last over 10,000 thermal cycles whereas QFN components tend to fail at around 1,000-3,000 cycles.
Historically, reliability testing has been mainly driven by JEDEC, however this has primarily focused on die and 1st level interconnects. IPC-9071A attempted to address this by focusing on 2nd level interconnects (i.e. package to PCB substrate). The challenge with this standard is that it has been more adopted by OEMs than component manufacturers, who tend to view it as an application-specific issue. As a result there has been much experimental testing and finite element analysis across various QFN package variants to characterize their reliability and solder fatigue behavior.
Serebreni et al. proposed a semi-analytical model to assess the reliability QFN solder joints under thermal cycling. This model generates effective mechanical properties for the QFN package, and calculates the shear stress and strain using a model proposed by Chen and Nelson. The dissipated strain energy density is then determined from these values and used to predict characteristic cycles to failure using a 2-parameter Weibull curve.
Comparison to other packages.
The QFN package is similar to the quad flat package, but the leads do not extend out from the package sides. It is hence difficult to hand-solder a QFN package, inspect solder joint quality, or probe lead(s).
Variants.
Different manufacturers use different names for this package: ML (micro-leadframe) versus FN (flat no-lead), in addition there are versions with pads on all four sides (quad) and pads on just two sides (dual), thickness varying between 0.9–1.0 mm for normal packages and 0.4 mm for extremely thin. Abbreviations include:
Micro lead frame package (MLP) is a family of integrated circuit QFN packages, used in surface mounted electronic circuits designs. It is available in 3 versions which are MLPQ (Q stands for "quad"), MLPM (M stands for "micro"), and MLPD (D stands for "dual"). These package generally have an exposed die attach pad to improve thermal performance. This package is similar to chip scale packages (CSP) in construction. MLPD are designed to provide a footprint-compatible replacement for small-outline integrated circuit (SOIC) packages.
Micro lead frame (MLF) is a near CSP plastic encapsulated package with a copper leadframe substrate. This package uses perimeter lands on the bottom of the package to provide electrical contact to the printed circuit board. The die attach paddle is exposed on the bottom of the package surface to provide an efficient heat path when soldered directly to the circuit board. This also enables stable ground by use of down bonds or by electrical connection through a conductive die attach material.
A more recent design variation which allows for higher density connections is the "dual row micro lead frame" (DRMLF) package. This is an MLF package with two rows of lands for devices requiring up to 164 I/O. Typical applications include hard disk drives, USB controllers, and wireless LAN.


Gold plating

Gold plating is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver (to make silver-gilt), by chemical or electrochemical plating. This article covers plating methods used in the modern electronics industry; for more traditional methods, often used for much larger objects, see gilding.
Types.
There are several types of gold plating used in the electronics industry:
Gold plating chemistry.
There are five recognized classes of gold plating chemistry:
Jewelry.
Gold plating of silver is used in the manufacture of jewelry. The thickness of gold plating on jewellery is noted in microns (or micro-meters). The microns of thickness determines how long the gold plating lasts with usage. The jewellery industry denotes different qualities of gold plating in the following terminology
Gold plated silver jewellery can still tarnish as the silver atoms diffuse into the gold layer, causing slow gradual fading of its color and eventually causing tarnishing of the surface. This process may take months and even years, depending on the thickness of the gold layer. A barrier metal layer is used to counter this effect - these can be nickel or rhodium. Copper, which also migrates into gold, does so more slowly than silver. The copper is usually further plated with nickel. A gold-plated silver article is usually a silver substrate with layers of copper, nickel, and gold deposited on top of it.
Infrared reflectivity.
Gold, applied by evaporated methods or electroplating, has been specified by NASA to thermally control spacecraft instruments, due to its 99% reflectivity in infrared wavelengths.
Electronics.
Gold plating is often used in electronics, to provide a corrosion-resistant electrically conductive layer on copper, typically in electrical connectors and printed circuit boards.
With direct gold-on-copper plating, the copper atoms tend to diffuse through the gold layer, causing tarnishing of its surface and formation of an oxide and/or sulphide layer.
A layer of a suitable barrier metal, usually nickel, is often deposited on the copper substrate before the gold plating. The layer of nickel provides mechanical backing for the gold layer, improving its wear resistance. It also reduces the impact of pores present in the gold layer.
Both the nickel and gold layers can be plated by electrolytic or electroless processes. There are many factors to consider in selection of either electrolytic or electroless plating methods. These include what the deposit will be used for, configuration of the part, materials compatibility and cost of processing. In different applications, electrolytic or electroless plating can have cost advantages.
At higher frequencies, the skin effect may cause higher losses due to higher electrical resistance of nickel; a nickel-plated trace can have its useful length shortened three times in the 1 GHz band in comparison with the non-plated one. Selective plating is used, depositing the nickel and gold layers only on areas where it is required and does not cause the detrimental side effects.
Gold plating may lead to formation of gold whiskers.
Wire bonding between gold plated contacts and aluminium wires or between aluminium contacts and gold wires under certain conditions develops a brittle layer of gold-aluminium intermetallics, known as purple plague.
Soldering issues.
Soldering gold-plated parts can be problematic as gold is soluble in solder. Solder which contains more than 4–5% gold can become brittle. The joint surface is dull-looking.
Gold reacts with both tin and lead in their liquid state, forming brittle intermetallics. When eutectic 63% tin – 37% lead solder is used, no lead-gold compounds are formed, because gold preferentially reacts with tin, forming the compound. Particles of disperse in the solder matrix, forming preferential cleavage planes, significantly lowering the mechanical strength and therefore reliability of the resulting solder joints.
If the gold layer does not completely dissolve into the solder, then slow intermetallic reactions can proceed in the solid state as the tin and gold atoms cross-migrate. Intermetallics have poor electrical conductivity and low strength. The ongoing intermetallic reactions also cause Kirkendall effect, leading to mechanical failure of the joint, similar to the degradation of gold-aluminium bonds known as purple plague.
A 2–3 µm layer of gold dissolves completely within one second during typical wave soldering conditions. Layers of gold thinner than 0.5 µm (0.02 thou) also dissolve completely into the solder, exposing the underlying metal (usually nickel) to the solder. Impurities in the nickel layer can prevent the solder from bonding to it. Electroless nickel plating contains phosphorus. Nickel with more than 8% phosphorus is not solderable. Electrodeposited nickel may contain nickel hydroxide. An acid bath is required to remove the passivation layer before applying the gold layer; improper cleaning leads to a nickel surface difficult to solder. A stronger flux can help, as it aids dissolving the oxide deposits. Carbon is another nickel contaminant that hinders solderability.


Swaging

Swaging  is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.
The term swage may apply to the process (verb) or to a die or tool (noun) used in that process.
Origin.
The term "swage" comes from the Old French term , meaning "decorative groove" or "ornamental moulding". Swages were originally tools used by blacksmiths to form metal into various shapes too intricate to make with a hammer alone. These have handles for holding or pegs for attaching to an anvil, and often a flat head for striking with a hammer. Swage blocks are anvil-like dies with various shapes forged into them, which are also used for forming metal. Swages called "fullers" are specific to making grooves in swords and knives.
"Swage" is most often pronounced (AHD format: swāj). Another (less common) pronunciation sometimes heard in the metalworking industries is (AHD format: swĕj) (perhaps influenced by "sledge" as in "sledgehammer").
Process.
As a general manufacturing process swaging may be broken up into two categories:
Tubes may be tagged (reduced in diameter to enable the tube to be initially fed through the die to then be pulled from the other side) using a rotary swager, which allows them to be drawn on a draw bench. Swaging is normally the method of choice for precious metals since there is no loss of material in the process.
Rotary swaging is usually a cold working process, used to reduce the diameter, produce a taper, or add a point to a round workpiece. It can also impart internal shapes in hollow workpieces through the use of a mandrel (the shape must have a constant cross-section). Swaging a bearing into a housing means either flaring its groove's lips onto the chamfer of the housing, or flaring the housing's material over the edge of the bearing. The flaring is done with a pair of rolls that travel around the hole and are fed down into the part, deforming the metal in a controlled, predicted way. Grease is often used to lubricate this swaging process, which is also called "roller swaging".
A swaging machine works by using two or four split dies which separate and close up to 2,000 times a minute. This action is achieved by mounting the dies into the machine's spindle which is rotated by a motor. The spindle is mounted inside a cage containing rollers (looks like a roller bearing). The rollers are larger than the cage so as the spindle spins the dies are pushed out to ride on the cage by centrifugal force, as the dies cross over the rollers they push the dies together because of their larger size. On a four-die machine, the number of rollers cause all dies to close at a time; if the number of rollers do not cause all pairs of dies to close at the same time then the machine is called a rotary forging machine, even though it is still a swaging process.
A variation of the rotary swager is the "creeping spindle" swaging machine where both the spindle and cage revolve in opposite directions, this prevents the production of fins between the dies where the material being swaged grows up the gap between the dies.
There are two basic types of rotary swaging machine, the standard (also known as a tagging machine), and the "butt swaging" machine. A butt swaging machine works by having sets of wedges that close the dies onto the workpiece by inserting them between the annular rollers and the dies, normally by the use of a foot pedal. A butt swaging machine can allow a workpiece to be inserted without the dies closing on it, for example a workpiece can be inserted and then the dies closed, drawn through until remain and the dies are then released, the finished workpiece would then, for example, be but still of its initial diameter for at each end.
Uses.
Blacksmithing.
Swages are used for shaping the metal in various ways, to enhance its beauty or its fit for a desired purpose.
Electronics.
In printed circuit board assembly individual connector pins are sometimes pressed/swaged into place using an arbor press. Some pins have a hollow end that is pressed over by the arbor's tool to form a mushroom-shaped retaining head. Typical pin diameter range from 0.017 to 0.093 inches (0.43 mm to 2.36 mm) or larger. The swaging is an alternative or supplement to soldering.
Plastics.
Heat swaging is a similar process to heat staking, but it involves rolling or reforming a wall (typically a perimeter) of a plastic part to retain another part or component.
Pipes and cables.
The most common use of swaging is to attach fittings to pipes or cables (also called wire ropes); the parts loosely fit together, and a mechanical or hydraulic tool compresses and deforms the fitting, creating a permanent joint. Pipe flaring machines are another example. Flared pieces of pipe are sometimes known as "swage nipples", "pipe swages", or "reducing nipples". In furniture, legs made from metal tubing (particularly in commercial furniture) are often swaged to improve strength where they come in contact with the ground, or casters.
Saw blade teeth.
In sawmills, a swage is used to flare large bandsaw or circle saw teeth, which increases the width of the cut, called the kerf. A clamp attaches a mandrel and die to the tooth and the eccentric die is rotated, swaging the tip. A much earlier version of the same operation used a hardened, shaped swage die and a hand held hammer. Saw teeth formed in this way are sometimes referred to as being "set". A finishing operation, shaping, cold works the points on the tooth sides to flats. It might be considered as a side swage. This slightly reduces the tooth width but increases the operating time between "fittings". Swaging is a major advance over filing as the operation is faster, more precise and greatly extends the working life of a saw.
Manufacturing.
When dealing with rubber components with mold bonded metal sleeves, swaging provides a more controlled and cost-effective alternative to 'shooting' the rubber part into a metal sleeve, where an intensive and less dependable secondary operation is needed to finish the product. A metal can with a bonding component (such as phosphate) is painted to the inside diameter, and molten rubber is injected into the metal sleeve. This creates a product that when cooled may be swaged to the desired size. The second reason for this is that the product is more reliable, and during the swaging process the rubber is more relaxed when the outside can to which the rubber is bonded has its diameter reduced, changing the springrate (K) values and damping coefficient (C) of the rubber. After swaging, any inconsistencies in the metal and rubber have been minimized.
Firearms.
In internal ballistics, swaging describes the process of the bullet entering the barrel and being squeezed to conform to the rifling. Most firearm bullets are made slightly larger than the inside diameter of the rifling, so that they are swaged to engage the rifling and form a tight seal upon firing. Compare to obturate.
In ammunition manufacture, swaged bullets are bullets manufactured by compressing metal at room temperature into a die to form it into the shape of a bullet. The other common manufacturing method is casting, which uses molten metals poured into a mold. Since metals expand when heated and contract when cooled, cast bullets must be cast with a mold slightly larger than the desired finish size, so that as the molten metal cools, it will harden at just the right point to shrink to the desired size. In contrast, swaged bullets, since they are formed at the temperature at which they will be used, can be formed in molds of the exact desired size. This means that swaged bullets are generally more precise than cast bullets. The swaging process also leads to fewer imperfections, since voids commonly found in casting would be pressed out in the swaging process. The swaging process in reference to cold flow of metals into bullets is the process not of squeezing the metals into smaller forms but rather pressing smaller thinner items to form into shorter and slightly wider shapes.
Individuals who make their own bullets usually are not aware of available manual specialized equipment and dies required for swaging bullets, and thus choose to make cast bullets. To get high precision results, it is common to cast the bullets slightly oversized, then swage the resulting castings through a die to do the final forming. Since the amount of pressure required to size the bullet is far less than that required to form a bullet, a simple mechanical press can be used, often the same press used for handloading ammunition.
All of the larger manufacturers of reloading equipment have abandoned making or marketing bullet swaging equipment due to the downturn in the popularity of the manual methods and the subsequent loss of sales. Currently there are only a few die makers who manufacture and market bullet swaging equipment. Four die and equipment makers, CH/4D, RCE, Corbin, and Custom Maker Kaine Dies, manufacture the bulk of bullet swaging equipment in the United States.
Medicine.
In surgery, the thread used in sutures is often swaged to an eyeless needle in order to prevent damage as the needle and suture thread are drawn through the wound.
Musical instrument repair.
In musical instrument repair the usual term on both sides of the Atlantic is swedging, not swaging, though it is generally acknowledged that the former derives from the latter. Keyed instruments such as the clarinet, bassoon, oboe and flute need swedging when years of key movement has worn or compressed the metal of the hinge tube they swivel on and made it slightly shorter, so that the key can travel along the rod it is mounted on instead of being held firmly between the posts attaching the rod to the body of the instrument. This gives rise to floppy keys and a poor air-seal and needs to be corrected by lengthening (swedging) the hinge tube. This is a job that needs to be done by hand, and swedging pliers with highly polished oval holes in the jaws to fit common sizes of hinge tubes are often used to achieve this, though various proprietary designs of swedging tools are available to do the same job more efficiently.
In piano technology, swaging happens in several areas: key leads, underlever leads, and bass strings. Key leads which, in the piano's earliest history, were actually made using lead, are soft, round chunks that are inserted into holes drilled into the side of piano keys as a means of balancing actions. Key leads vary in size, generally small, medium, and large. Basically, key leads help to make a keyboard's touch light enough to play. Over time, fluctuations in humidity and aging of wood in piano key-sticks and underlevers causes space to develop around leads, causing them to rattle, tick, or knock. Loose leads in underlevers tend to be the most annoying to pianists because it's difficult to pinpoint where the noise (often a "tick" sound) is coming from. The remedy for the noise is swaging—squashing the leads with a short steel rod. Swaging the lead fills the void and eliminates the noise.
Bass strings in pianos are generally constructed with round—sometimes hexagonal—drawn-steel cores, over which copper is wound. Especially on round core wire, the last several inches of the area where the winding terminates is often flattened—swaged—to create a grabbing point for the copper winding material.
Car styling.
As swaging is a technique in which cold metal is formed over a grooved tool or swage, the term was adopted in the field of automotive styling to describe when two panels were brought together, an edge of one panel was swaged so to overlap the other to create the impression of one continuous surface.
The term is now often used generically to refer to any similar designs.
Lockbolts.
A lockbolt is a fastener similar to a bolt in appearance and function. However, instead of using screw threads which connect to a nut using a turning motion, a lockbolt has annular grooves around the shaft of the bolt (pin). After placing the lockbolt in a hole, a threadless collar is forced at high pressures around the annular grooves, deforming the collar and permanently locking it into place around the grooves. Swaging is the generic term for setting a lockbolt and collar assembly. During the installation cycle of a lockbolt, the collar is deformed around the pin with locking grooves using special tooling. The tool engages onto the pintail, which is an extra portion of pin material protruding past the collar that the tool grabs and pulls. This force on the pintail pushes the joint together, and the conically-shaped cavity of the tooling is forced down the collar, which reduces its diameter and progressively swages the collar material into the grooves of the harder pin. As the force required for swaging increases during the process, the installation is finalised when the pintail breaks off. Lockbolts could be viewed as a heavy-duty cousin of structural blind rivets ("pop rivets" in some regions), though the way the collar material's plastic deformation is achieved is different. Some tools are capable of "setting" both variants, as in both cases traction is applied to a sacrificial pintail.


Electromagnetic forming

Electromagnetic forming (EM forming or magneforming) is a type of high-velocity, cold process for electrically conductive metals, most commonly copper and aluminium. The workpiece is reshaped by high-intensity pulsed magnetic fields that induce a current in the workpiece and a corresponding repulsive magnetic field, rapidly repelling portions of the workpiece. The workpiece can be reshaped without any contact from a tool, although in some instances the piece may be pressed against a die or former. The technique is sometimes called "high-velocity forming" or "electromagnetic pulse technology".
Explanation.
A special coil is placed near the metallic workpiece, replacing the pusher in traditional forming. When the system releases its intense magnetic pulse, the coil generates a magnetic field which in turn accelerates the workpiece to hyper speed and onto the die.
The magnetic pulse and the extreme deformation speed transforms the metal into a visco-plastic state – increasing formability without affecting the native strength of the material. See the magnetic pulse forming illustration for a visualization.
A rapidly changing magnetic field induces a circulating electric current within a nearby conductor through electromagnetic induction. The induced current creates a corresponding magnetic field around the conductor (see Pinch (plasma physics)). Because of Lenz's Law, the magnetic fields created within the conductor and work coil strongly repel each other.
In practice the metal workpiece to be fabricated is placed in proximity to a heavily constructed coil of wire (called the "work coil"). A huge pulse of current is forced through the work coil by rapidly discharging a high-voltage capacitor bank using an ignitron or a spark gap as a switch. This creates a rapidly oscillating, ultrastrong electromagnetic field around the work coil.
The high work coil current (typically tens or hundreds of thousands of amperes) creates ultrastrong magnetic forces that easily overcome the yield strength of the metal work piece, causing permanent deformation. The metal forming process occurs extremely quickly (typically tens of microseconds) and, because of the large forces, portions of the workpiece undergo high acceleration reaching velocities of up to 300 m/s.
Applications.
The forming process is most often used to shrink or expand cylindrical tubing, but it can also form sheet metal by repelling the work piece onto a shaped die at a high velocity. High-quality joints can be formed, either by electromagnetic pulse crimping with a mechanical interlock or by electromagnetic pulse welding with a true metallurgical weld. Since the forming operation involves high acceleration and deceleration, mass of the work piece plays a critical role during the forming process. The process works best with good electrical conductors such as copper or aluminum, but it can be adapted to work with poorer conductors such as steel.
Comparison with mechanical forming.
Electromagnetic forming has a number of advantages and disadvantages compared to conventional mechanical forming techniques.
Some of the advantages are;
The principle disadvantages are;


Timeline of the COVID-19 pandemic in India (June–December 2020)

The following is the timeline of the COVID-19 pandemic in India.
June.
1 June.
204 deaths and 8,171 cases were reported. New cases were reported in the states/UTs as following:
Assam: 22 cases
Odisha: 156 cases
Delhiː 990 cases
Maharashtraː 2,361 cases
2 June̝.
217 deaths and 8,909 cases were reported. New cases were reported in the states/UTs as following:
Andhra Pradeshː 115 cases
Tamil Naduː 1,091 cases
Keralaː 86 cases
3 June̝.
293 deaths and 9,304 cases were reported. New cases were reported in the states/UTs as following:
Tamil Naduː 1,286 cases
Andhra Pradeshː 79 cases
Keralaː 82 cases
Maharashtraː 2,560 cases
4 June.
273 deaths and 9,851 cases were reported. New cases were reported in the states/UTs as following:
Andhara Pradesh: 98 cases
Maharashtraː 2,933 cases
Gujaratː 485 cases
Tamil Naduː 1373 cases
5 June.
294 deaths and 9,887 cases were reported. New cases were reported in the states/UTs as following:
Andhra Pradesh: 50 cases
Maharashtraː 2436 cases
Tamil Nadu: 1,438 cases
Karnataka: 515 cases
6 June.
287 deaths and 9,971 cases were reported. New cases were reported in the states/UTs as following:
Karnataka: 378 cases
Bihar: 147 cases
Andhra Pradesh: 161 cases
Maharashtraː 2,739 cases
Gujaratː 498 cases
7 June.
271 deaths and 9,983 cases were reported. New cases were reported in the states/UTs as following:
Andhra Pradesh: 130 cases
Delhi: 1,320 cases
8 June.
271 deaths and 9,983 cases were reported. New cases were reported in the states/UTs as following: New cases were reported in the states/UTs as following:
Andhra Pradesh: 125 cases
Odisha: 138 cases
Kerala: 91 cases
9 June.
274 deaths and 9985 cases were reported.
Tamil Nadu: 1,685 cases
Andhra Pradesh: 147 cases
Karnataka: 161 cases
10 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 1927 cases
Karnataka: 120 cases
Andhra Pradesh: 218 cases
11 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 1875 cases
Karnataka: 204 cases
Andhra Pradesh: 135 cases
12 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 1982 cases
Andhra Pradesh: 141 cases
Odisha: 112 cases
14 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 1974 cases.
Karnataka: 176 cases.
Andhra Pradesh: 253 cases.
15 June.
New cases were reported in the states/UTs as following:
Kartataka: 213 cases.
Tamil Nadu: 1843 cases.
16 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 1515 cases.
Karnataka: 317 cases.
17 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 2174 cases.
West Bengal: 391 cases.
Andhra Pradesh: 275 cases.
18 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 2141 cases.
Karnataka: 210 cases.
Andhra Pradesh: 210 cases.
19 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 2115 cases.
Gujarat: 540 cases.
20 June.
New cases were reported in the states/UTs as following:
Karnataka: 416 cases.
Tamil Nadu: 2396 cases.
21 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 2352 cases.
Karnataka:453 cases.
Andhra Pradesh: 477 cases.
23 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 2516 cases.
Andhra ̪Pradesh: 462 cases.
24 June.
New cases were reported in the states/UTs as following:
Maharastra: 3890 cases.
Tamil Nadu:2865 cases.
25 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 2509 cases.
Andhra Pradesh: 553 cases.
26 June.
New cases were reported in the states/UTs as following:
Tamil Nadu: 3523 cases.
Maharashtraː 5024 cases.
27 June.
New cases were reported in the states/UTs as following:
Delhiː 2948 cases.
Tamil Naduː 3713 cases.
28 June.
New cases were reported in the states/UTs as following:
Delhiː 2889 cases.
Tamil Naduː 3940 cases.
29 June.
New cases were reported in the states/UTs as following:
Tamil Naduː 3949 cases.
30 June.
New cases were reported in the states/UTs as following:
Tamil Naduː 3943 cases.
Keralaː 131 cases.
July.
1 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 3882 cases
Uttar Pradesh: 564 cases
2 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 4343 cases.
Punjab: 120 cases.
3 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 4329 cases.
Kerala: 211 cases.
4 July.
New cases were reported in the states/UTs as following:
Delhi: 2505 cases.
Tamil Nadu: 4280 cases.
5 July.
New cases were reported in the states/UTs as following:
Delhi: 2244 cases.
Andhra Pradesh: 2244 cases.
6 July.
New cases were reported in the states/UTs as following:
Maharashtra: 5368 cases.
Tamil Nadu: 3827 cases.
7 July.
New cases were reported in the states/UTs as following:
Uttar Pradesh: 1346 cases.
Maharashtra: 5134 cases.
8 July.
New cases were reported in the states/UTs as following:
Kerala: 301 cases.
Tamil Nadu: 3756 cases.
9 July.
New cases were reported in the states/UTs as following:
Andhra Pradesh: 155 cases.
Delhi: 2187 cases.
10 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 3680 cases.
Andhra Pradesh: 1608 cases.
11 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 3965 cases.
Andhra Pradesh: 1813 cases.
12 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 4244 cases.
Delhi: 1574 cases.
13 July.
New cases were reported in the states/UTs as following:
Uttar Pradesh: 1644 cases.
Tamil Nadu: 4328 cases.
15 July.
New cases were reported in the states/UTs as following:
Kerala: 623 cases.
Andhra Pradesh: 2432 cases.
16 July.
New cases were reported in the states/UTs as following:
Maharashtra: 8641 cases.
Karnataka: 4169 cases.
17 July.
New cases were reported in the states/UTs as following:
Maharashtra: 8308 cases.
Karnataka: 3693 cases.
18 July.
New cases were reported in the states/UTs as following:
Delhi: 1475 cases.
Tamil Nadu: 4807 cases.
19 July.
New cases were reported in the states/UTs as following:
Delhi: 1211 cases.
20 July.
New cases were reported in the states/UTs as following:
Andhra Pradesh: 4074 cases.
Kerala: 794 cases.
21 July.
New cases were reported in the states/UTs as following:
Delhi: 1349 cases.
Tamil Nadu: 4965 cases.
22 July.
New cases were reported in the states/UTs as following:
Maharashtra: 10576 cases.
23 July.
New cases were reported in the states/UTs as following:
Maharashtra: 9895 cases.
24 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 6785 cases.
25 July.
New cases were reported in the states/UTs as following:
Delhi: 1142 cases.
Tamil Nadu: 6988 cases.
26 July.
New cases were reported in the states/UTs as following:
Rajasthan: 1120 cases.
27 July.
New cases were reported in the states/UTs as following:
Maharashtra: 7924 cases.
28 July.
New cases were reported in the states/UTs as following:
Maharashtra: 7717 cases.
29 July.
New cases were reported in the states/UTs as following:
Tamil Nadu: 6426 cases.
30 July.
New cases were reported in the states/UTs as following:
Andhra Pradesh: 10167 cases.
31 July.
New cases were reported in the states/UTs as following:
Maharashtra: 10167 cases.
August.
1 August.
Kerala: 1129 cases.
Tamil Nadu: 5879 cases.
2 August.
Maharashtra: 9509 cases.
8 August.
Indian Medical Association says nearly 198 doctors died due to COVID.
December.
lock down started on 28 December 2022 19,855 cases


Finished goods

Finished goods are goods that have completed the manufacturing process but have not yet been sold or distributed to the end user.
Manufacturing.
Manufacturing has three classes of inventory:
A good purchased as a "raw material" goes into the manufacture of a product. A good only partially completed during the manufacturing process is called "work in process". When the good is completed as to manufacturing but not yet sold or distributed to the end-user, it is called a "finished good".
This is the last stage for the processing of goods. The goods are ready to be consumed or distributed.
There is no processing required in term of the goods after this stage by the seller. Though there maybe instance that seller finished goods become buyer’s raw materials
Finished goods is a relative term. In a Supply chain management flow, the finished goods of a supplier can constitute the raw material of a buyer.


Flash (manufacturing)

Flash, also known as flashing, is excess material attached to a molded, forged, or cast product, which must usually be removed. This is typically caused by leakage of the material between the two surfaces of a mold (beginning along the parting line) or between the base material and the mold in the case of overmolding.
Details.
Molding flash is seen when the optimized parameter on cull height is not calibrated. Proper design of mold parting surfaces can reduce or eliminate flash.
Molding flash can be caused from old or worn mold cavities that no longer fit tightly together. Other times, the complexity of the part requires so many mating pieces with such precise geometries that it is almost impossible to create a perfect fit on every impression. Most often, the type of material being molded, and its attendant viscosity in its liquid form, is the primary factor that leads to the creation of the unwanted mold flash.
The process of removing flash, known as deflashing, is commonly performed via cutting, breaking, grinding, or tumbling. Some foundries use robot autogrinders to remove this unwanted material. It is very typical for molders to have their operators trim flash with hand tools at the molding machine between cycles. Many molders and OEMs seek out the use of batch processes including vibratory tumbling, cryogenic deflashing or media blasting to remove unwanted flash from large batches of parts.
Witness mark.
In plastic injection, a faint mark called a witness mark (or witness line) will occur along the parting line. This is unavoidable and is usually accepted despite the minor aesthetics issue. However, some part surfaces (e.g. when used for sealing) cannot tolerate witness marks, and thus either the marks must be removed post-molding or the mold redesigned.


Harsco

Harsco Corporation is an environmental solutions company based in Philadelphia, Pennsylvania. Harsco operates in over 30 countries and employs approximately 12,000 people worldwide. The company provides solutions for complex environmental issues and serves large industries, including steel, railways, and energy. Harsco's common stock is a component of the S&P SmallCap 600 Index and the Russell 2000 Index.
History.
Harsco was founded in 1853 as The Harrisburg Car Manufacturing Company and became the Harrisburg Steel Corporation in 1935. Following a series of acquisitions, the company became Harsco Corporation in 1956, forming three divisions: Metals & Minerals (Now Harsco Environmental), Rail, and Industrial.
By the early 1990s, Harsco products and services covered defense, industrial, commercial, and construction applications, with over 250 manufacturing, reclamation, distribution, and service facilities across 14 countries.
In 2018, Harsco acquired Altek, a UK producer of aluminum processing equipment.
In 2019, Harsco Metals & Minerals rebranded to Harsco Environmental, and acquired Clean Earth, a U.S. provider of environmentally sustainable solutions for specialty waste streams.
In April 2020, Harsco Corporation acquired the Environmental Solutions business (ESOL) from Stericycle, Inc.
Harsco currently operates as the mother company with its two main divisions Clean Earth and Harsco Environmental. Additional subsidiary companies include ALTEK, SteelPhalt, and Black Beauty Abrasives.
Financial information.
Harsco reported total sales of USD $1.89 billion in fiscal year 2022.
Stock exchanges.
Harsco is traded publicly on NYSE with ticker symbol HSC.


Hand mould

A hand mold is a simple mold used for low quantity work. It is used in the injection molding and printing industries.
It is made by a hand injection molding machine. It is a simple machine which contains a barrel, handle, nozzle, mold and heaters.
Printing.
In the printing industry, a hand mold specifically refers to a two-part mold used for casting hand-made type. Inside the mold is a matrix.
In particular, it refers to a system for casting movable type, pioneered by Johannes Gutenberg, which was widely used in the early era of printing in Europe (15th-16th century).
In this method, the type was made by punching a letter-shaped cavity in a matrix made of some soft metal (typically copper). Then this matrix would be held in the lower part of the mold, the upper part would close on it, and molten type metal would be poured into the cavity. Using the hand mold, the printer could quickly make any additional type he might need.
Injection molding.
In injection molding, hand molds refer to simple molds that have no provision for heat, cooling, or ejection. This means when a hand mold is cycled universal heating plates are required to warm the molds and the molds must be removed after each cycle to remove the moldings. This drastically increases the cycle time, which limits it to short runs, but to offset this is the low cost of the mold. They are usually single cavity molds, but may be multi-cavity if the molding is quite small. They are usually only of a two or three plate design because of the simplicity of the parts. If only a short run is required then the molds may be made from aluminum or brass, but if more parts are required then they are made from conventional steels.
Bullet casting.
Hand cast bullets remain popular with the handloading, muzzleloading and small custom ammunition loading communities. In a tradition dating back to the beginning of firearms, molds matched to the bore (and the chamber for breech loading weapons) are custom made for each weapon. Anywhere from one to six cavities are carved into the molding block, along with appropriate gates and sprues. As the blocks are now usually made out of aluminum, which does not allow lead alloys to stick, only a small amount of parting compound is needed.


Router table (woodworking)

A router table is a stationary woodworking machine in which a vertically oriented spindle of a woodworking router protrudes from the machine table and can be spun at speeds typically between 3000 and 24,000 rpm. Cutter heads (router bits) may be mounted in the spindle chuck. As the workpiece is fed into the machine, the cutters mold a profile into it. The machine normally features a vertical fence, against which the workpiece is guided to control the horizontal depth of cut. Router tables are used to increase the versatility of a hand-held router, as each method of use is particularly suited to specific application, e.g. very large workpieces would be too large to support on a router table and must be routed with a hand-held machine, very small workpieces would not support a hand-held router and must be routed on a router table with the aid of pushtool accessories etc.
Varieties.
Router tables exist in three varieties:
Use.
Router tables are used in one of three ways. In all cases, an accessory is used to direct the workpiece.
History.
Router tables evolved as shop improvised tools. Individual woodworkers began taking routers, mounting them in an inverted position beneath a table, and using the routers' depth adjustment to raise the bit through a hole in the table surface.
Over time manufacturers began selling accessories (pre-made table tops, table legs, table inserts, fences, hold downs, vertical adjustment tools ("lifts"), etc.
Finally, manufacturers began selling complete packages, such as the Inverted Pin Router, which put them in the business of effectively selling wood shapers, the very tool that shop improvised router tables were created as inexpensive substitutes for.


Low plasticity burnishing

Low plasticity burnishing (LPB) is a method of metal improvement that provides deep, stable surface compressive residual stresses with little cold work for improved damage tolerance and metal fatigue life extension. Improved fretting fatigue and stress corrosion performance has been documented, even at elevated temperatures where the compression from other metal improvement processes relax. The resulting deep layer of compressive residual stress has also been shown to improve high cycle fatigue (HCF) and low cycle fatigue (LCF) performance.
History.
Unlike LPB, traditional burnishing tools consist of a hard wheel or fixed lubricated ball pressed into the surface of an asymmetrical work piece with sufficient force to deform the surface layers, usually in a lathe. The process does multiple passes over the work pieces, usually under increasing load, to improve surface finish and deliberately cold work the surface. Roller and ball burnishing have been studied in Russia and Japan, and were applied most extensively in the USSR in the 1970s. Various burnishing methods are used, particularly in Eastern Europe, to improve fatigue life. Improvements in HCF, corrosion fatigue and SCC are documented, with fatigue strength enhancement attributed to improved finish, the development of a compressive surface layer, and the increased yield strength of the cold worked surface.
LPB was developed and patented by Lambda Technologies in Cincinnati, Ohio in 1996. Since then, LPB has been developed to produce compression in a wide array of materials to mitigate surface damage, including fretting, corrosion pitting, stress corrosion cracking (SCC), and foreign object damage (FOD), and is being employed to aid in daily MRO operations. To this day, LPB is the only metal improvement method applied under continuous closed-loop process control and has been successfully applied to turbine engines, piston engines, propellers, aging aircraft structures, landing gear, nuclear waste material containers, biomedical implants, armaments, fitness equipment and welded joints. The applications involved titanium, iron, nickel and steel-based components and showed improved damage tolerance as well as high and low cycle fatigue performance by an order of magnitude.
How it works.
The basic LPB tool is a ball, wheel or other similar tip that is supported in a spherical hydrostatic bearing. The tool can be held in any CNC machine or by industrial robots, depending on the application. The machine tool coolant is used to pressurize the bearing with a continuous flow of fluid to support the ball. The ball does not contact the mechanical bearing seat, even under load. The ball is loaded at a normal state to the surface of a component with a hydraulic cylinder that is in the body of the tool. LPB can be performed in conjunction with chip forming machining operations in the same CNC machining tool.
The ball rolls across the surface of a component in a pattern defined in the CNC code, as in any machining operation. The tool path and normal pressure applied are designed to create a distribution of compressive residual stress. The form of the distribution is designed to counter applied stresses and optimize fatigue and stress corrosion performance. Since there is no shear being applied to the ball, it is free to roll in any direction. As the ball rolls over the component, the pressure from the ball causes plastic deformation to occur in the surface of the material under the ball. Since the bulk of the material constrains the deformed area, the deformed zone is left in compression after the ball passes.
Benefits.
The LPB process includes a unique and patented way of analyzing, designing, and testing metallic components in order to develop the unique metal treatment necessary to improve performance and reduce metal fatigue, SCC, and corrosion fatigue failures. Lambda modifies the process and tooling for each component to provide the best results possible and to ensure that the apparatus reaches every inch on the component. With this practice of customization along with the closed-loop process control system, LPB has been shown to produce a maximum compression of 12mm, although the average is around 1-7+mm. LPB has even been shown to have the ability to produce through-thickness compression in blades and vanes, greatly increasing their damage tolerance over 10-fold, effectively mitigating most FOD and reducing inspection requirements. No material is removed during this process, even when correcting corrosion damage. LPB smooths surface asperities during machining, leaving an improved, almost mirror-like surface finish that is vastly better looking and better protected than even a newly manufactured component.
Cold working.
The cold work produced from this process is typically minimal, similar to the cold work produced by laser peening, only a few percent, but a great deal less than shot peening, gravity peening or, deep rolling. Cold work is particularly important because the higher the cold work at the surface of a component, the more vulnerable to elevated temperatures and mechanical overload that component will be and the easier the beneficial surface residual compression will relax, rendering the treatment pointless. In other words, a component that has been highly cold worked will not hold the compression if it comes into contact with extreme heat, like an engine, and will be just as vulnerable as it was to start. Therefore, LPB and laser peening stand out in the surface enhancement industry because they are both thermally stable at high temperatures. The reason LPB produces such low percentages of cold work is because of the aforementioned closed-loop process control. Conventional shot peening processes have some guesswork involved and are not exact at all, causing the procedure to have to be performed multiple times on one component. For example, shot peening, in order to make sure every spot on the component is treated, typically specifies coverage of between 200% (2T) and 400% (4T). This means that at 200% coverage (2T), 5 or more impacts occur at 84% of locations and at 400% coverage (4T), it is significantly more. The problem is that one area will be hit several times while the area next to it is hit fewer times, leaving uneven compression at the surface. This uneven compression results in the whole process being easily "undone", as was mentioned above. LPB requires only one pass with the tool and leaves a deep, even, beneficial compressive stress.
The LPB process can be performed on-site in the shop or in situ on aircraft using robots, making it easy to incorporate into everyday maintenance and manufacturing procedures. The method is applied under continuous closed loop process control (CLPC), creating accuracy within 0.1% and alerting the operator and QA immediately if the processing bounds are exceeded. The limitation of this process is that different CNC processing codes need to be developed for each application, just like any other machining task. The other issue is that because of dimensional restrictions, it may not be possible to create the tools necessary to work on certain geometries, although that has yet to be a problem.


Product concept

A product concept is a description of a product or service, at an early stage in the product lifecycle. It is generated before any detailed design work is undertaken and takes into consideration market analysis, customer experience, product features, product cost, strategic fit, and product architecture.
A product concept should describe how the new product will appeal to its target market. While the product concept is based upon the idea that customers prefer products that have the most quality, performance, and features, some customers prefer a product that is simpler and easier to use.


Green strength

Green strength, or handling strength, can be defined as the strength of a material as it is processed to form its final ultimate tensile strength. This strength is usually considerably lower than the final ultimate strength of a material. The term green strength is usually referenced when discussing non-metallic materials such as adhesives and elastomers (such as rubber). Recently, it has also been referenced in metallurgy applications such as powdered metallurgy.
Adhesives.
A joint made through the use of an adhesive can be referred to as an adhesive joint or bond.
The green strength of adhesives is the early development of bond strength of an adhesive. It indicated "that the adhesive bond is strong enough to be handled a short time after the adherents are mated but much before full cure is obtained." Usually, this strength is significantly lower than the final curing strength. Most adhesives typically have an initial green strength and a final ultimate tensile strength listed for their application. For household adhesives, this data is usually reflected on the packaging.
The best example of this is seen in typical epoxies from a local hardware stores. During curing, the epoxy will travel into an initial curing phase, also called "green phase", when it begins to gel. At that point, the epoxy is no longer workable and will move from being tacky to a firm rubber-like texture. While the epoxy is only partially cured at this point, it has formed a lower green strength. Normally, this process occurs within 30 minutes to 1 hour. At this time, the part in question can be handled, but cannot handle large loads or stress. It typically takes up to 24 hours for a standard epoxy to cure to its final and complete strength.
Temperature is an important factor in the time it takes for an adhesive to form the green strength. While this can vary from adhesive to adhesive, general speaking, heat can speed up the process to form the green strength and the overall curing time. Time-Temperature-Transformation Diagrams exist for various adhesives that relate the time and temperature to the state of the adhesive during curing. This allows for a proper understanding of when the green strength will be reached for an adhesive joint based on certain conditions.
Testing.
Mechanical testing can be used to verify the green strength of a material. This will allow the user the understand the amount of load that can be applied in the green phase before final cure.
Tensile loading can be verified by various testing methods. Multiple ASTM specifications exist for the tensile testing of adhesives that are relatively easy to follow. Such tests include the process of attaching the adhesive to two adherents (typically wood or steel) then testing the joint with a pull-type test. One example is the use us ASTM Test Method D2095. In this test, two metal rod ends are polished so it contains no burrs that could affect the adhesive bond. It also machined so the surfaces are perfectly parallel. The rods are then butted against each with the adhesive joining them. As it cures and sets, the fulfillment of green strength can be tested by a pull test, putting the bond in full tension load.
Shear loading can also be tested in respect to green strength. Most adhesive bonds used in design require the bond to typically be in a state of shear, not tensile. Because of this, it is very important to understand the shear loading of a joint in relation to its green strength and final strength. Just like in tensile loading, ASTM provides very specific testing methods for a joint in shear loading.
The standard lap shear specimen test is described in ASTM D1002. This test is the single common and discussed test method for adhesive bonds. In this method, the surface is prepped and cleaned for each specimen. The adhesive is then applied to the area that will be lapped. This lap length is generally 0.5" and the bond width is 1". The bond is then fixed and allowed to cure. For green strength testing, the fixture can be removed, at the appropriate time, and the specimen can be loaded in shear until it finally fails. This will verify the green strength of the material.
Other testing, such as cleavage loading and peel test, can be used to determine both the green strength and final strength of a material. These are typically not reflected on the data sheet for standard adhesives, but can be used for testing of adhesives based on their applications in residential and commercial environments.
Elastomers.
In the elastomer industry, "green strength" describes the strength of an elastomer in an unvulcanized, uncured state. The most popular referenced type of elastomer is rubber.
For rubber composites, green strength is essential during formation and manufacturing of materials such as radial tires, tank tracks, etc. These rubbers must be stretched from one mill to another during processing to form the final, vulcanized product. Green strength allows these transfers without tearing or wrinkling the workpiece.
To improve the green strength of elastomers and prevent issues during forming, various additives and compounds are typically added to the composite. Also, fabrication and forming techniques have been modified to reduce the amount of stress on the material before it is vulcanized. These techniques are a pertinent component of the tire making industry because it is a process that requires much forming, stretching, and bending during fabrication before the final curing is complete.
Metals.
Green strength of metals is typically referenced in the field of powder metallurgy.
Powder metallurgy refers to the fabrication of materials or components from powders. In powder metallurgy, the initial green strength is formed during compacting and forming. Increased complexity of parts and geometry have created a need for a higher green strength during this process.
There are several limitations that restrict the ability to increase green strength in powder metallurgy components. Characteristics such as particle size and compressibility pose limits on the final green strength.
Various studies have been undertaken to improve the green strength of powder metallurgy. The use of advanced lubricants and the addition of high alloys have shown that it is possible to increase the green strength of these materials.


Welding of advanced thermoplastic composites

Advanced thermoplastic composites (ACM) have a high strength fibres held together by a thermoplastic matrix. Advanced thermoplastic composites are becoming more widely used in the aerospace, marine, automotive and energy industry. This is due to the decreasing cost and superior strength to weight ratios, over metallic parts. Advance thermoplastic composite have excellent damage tolerance, corrosion resistant, high fracture toughness, high impact resistance, good fatigue resistance, low storage cost, and infinite shelf life. Thermoplastic composites also have the ability to be formed and reformed, repaired and fusion welded.
Fusion bonding fundamentals.
Fusion bonding is a category of techniques for welding thermoplastic composites. It requires the melting of the joint interface, which decreases the viscosity of the polymer and allows for intermolecular diffusion. These polymer chains then diffuse across the joint interface and become entangled, giving the joint its strength.
Welding techniques.
There are many welding techniques that can be used to fusion bond thermoplastic composites. These different techniques can be broken down into three classifications for their ways of generating heat; frictional heating, external heating and electromagnetic heating. Some of these techniques can be very limited and only used for specific joints and geometries.
Friction welding.
Friction welding is best used for parts that are small and flat. The welding equipment is often expensive, but produces high-quality welds.
Linear vibration welding.
Two flat parts are brought together under pressure with one fixed in place and the other vibrating back-and-forth parallel to the joint. Frictional heat is then generated till the polymers are softened or melted. Once the desired temperature is met, the vibration motion stops, the polymer solidifies and a weld joint is made. The two most important welding parameters that affect the mechanical performance are welding pressure and time. Developing parameters for different advance thermoplastic composite can be challenging because the high elastic modulus of the material will have a higher heat generation, requiring less weld time. The pressure can affect the fiber orientation which also greatly impact the mechanical performance. Lap shear joints tend to have the best mechanical performance from the higher volume fraction of fibers at the weld interface. Overall linear vibration welding can achieve high production rates with excellent strength, but is limited to the joint geometries that are flat.
Spin welding.
Spin welding is not a very common welding technique for advanced thermoplastic composites because this can only be done with parts that have a circular geometry. This is done by one part remaining stationary while the other is continuously rotated with pressure applied to the weld interface. Rotational velocity will vary throughout different radii of the Interface. This will result in a temperature gradient as a function of the radius, resulting in different shrinkage for the fibers causing high residual stresses. The orientation of the fibers will also contribute to high residual stress and reduction in strength.
Ultrasonic welding.
Ultrasonics welding is one of the most commonly used technique for welding advanced thermoplastic composites. This is due for its ability to maintain high weld strength, hermetic sealing, and high production rates. This welding technique operates at high vibrational frequencies (10–70 kHz) and low amplitude. The direction of vibration is perpendicular to the joint surface, but can also be parallel to the joint for hermetic application. Heat is generated from the surface and intermolecular friction due to the vibrational. On the surface of the joint there are small asperities called energy directors, where the vibrational energy concentrates and induces melting. Design of the energy director and optimized parameters can be critical to improve the quality of the weld to reducing any fiber disruption during welding. Energy directors that are triangular or semi-circle often achieve the highest strength. With optimize welding parameters and joint design weld strength, up to 80% of the base material can be retained for advanced thermoplastic composites. However, welding can cause damage to the fibers, which will result in premature failure. Ultrasonic welding of advanced thermoplastic composites is used for making automotive parts, medical devices and battery housing.
Thermal welding.
Thermal welding can produce good weld quality although extra precautions need to be taken to prevent high residual stress, warping, and decohesion. Other thermal welding techniques are not commonly used due their high heat input, which can damage the composite.
Laser welding.
Laser welding of advanced thermoplastic composites is a process by which the LASER (Light Amplification of Simulated Emission of electromagnetic Radiation), a highly focused coherent beam of light melts the composite tin various ways. Taking advantage of joint design and material properties, lasers can be applied either directly or indirectly to create the welded joint. There are processing methods that take advantage of material structure/properties to create the weld joint. Welding variables affect weld quality in both positive and negative ways depending on how they are manipulated.
Laser heating mechanism in matter.
When a laser beam impinges on a material, it excites electrons in the outer most shell of the atom. The return of those electrons to the relaxed state induces thermal heating through conversion to vibrational states which propagate to the surrounding material.
Joining methods for laser welding.
Surface heating.
This method involves using infrared radiation to heat the surfaces the composites to be welded and then clamping until and holding the parts together.
IR/Laser stacking.
This method involves laser melting a polymer post and pressing a die into the molten post to create a rivet-like button to joint materials like metals. This process can be used to join metallic joints to composite structures.
Through Transmission IR welding (TTIr).
This method utilizes one laser transparent (LT) and one laser absorbing (LA) material. Typically, the components are layered as a sandwich with the laser beam passing through the LT layer and irradiating the surface of the LA. This creates a melt layer at the interface of two components leading to a weld.
Effect of Constituent Properties on Weldability.
To understand how the properties of a composite affect is weldability, the effects of the individual constituents (fiber, matrix, additives, etc.) need to be understood. The effect of each will be noted separately and then the combined effects will be discussed.
Matrix.
Electromagnetic radiation interaction.
A laser beam can interact in one of three ways when it contacts the polymer matrix. It can be absorbed, transmitted, or reflected. The amount of absorption determines the amount of energy available for welding. The reflectivity is affected by the index of refraction according to this relation: formula_1, where n is the index of refraction of the polymer and m is the index of refraction of air.
Absorption can be affected by the following structural characteristics of the polymer to be discussed below: crystallinity, chemical bonding, and concentration of additives.
Crystallinity.
Increased crystallinity tends to cause lower laser beam transmission because of scattering caused by changes in the index of refraction encountered when going from one phase to the next or because of changing crystallographic orientation. Increased crystallinity can cause the transmission to increase monotonically as a function of polymer thickness. The relationship follows the Lambert-Bouuger's Law: formula_2, where formula_3 is the intensity of the laser beam at a given depth or thickness, t. formula_4 is the intensity of laser beam at its source. formula_5 is the absorption constant of the polymer. By the same token, amorphous polymers lack this trend with thickness.
Chemical bonding.
Polymers absorb EMR (Electro Magnetic Radiation) in a specific wavelength of light depending on what functional groups are present on the polymer. For instance, bending of the C-H bond on the formula_6 at 6800 nm. Many polymers have vibrational modes at wavelengths greater than 1100 nm, so to apply methods such as TTIr, laser sources must produce photons at wavelengths shorter than that. Therefore, lasers (1064 nm) and diode lasers (800-950 nm) can pass through the LT until they impinge on the intended modified polymer or additive that results in absorption, whereas CO_2 lasers (10,640 nm) will be absorbed too easily as it passes through the LT.
Reinforcements.
Reinforcements such as fibers or short particles. Reinforcing fibers can be added to increase the strength of a composite.
Some reinforcements like carbon fibers have high thermal conductivity and can dissipate the heat of welding, thus requiring more energy input than with other reinforcement materials such as glass. Glass reinforcements can cause scattering of the beam.
The orientation of the continuous fibers can affect the width of welds being made. When the welding direction is parallel to the orientation of the fibers, the weld width is usually narrower due to heat being channeled through the fibers to the front and the rear of the weld.
Increased volume fraction of reinforcements such as glass can scatter the laser beam, thus allowing less to be transmitted to the weld joint. When this happens, the amount of energy necessary to fuse the joint may increase. The increase if not done carefully can cause damage to the transparent part of a TTIr weld joint.
Additives and Fillers.
Some additives can be intentionally added to absorb laser energy. This technique is especially useful in concentrating the weld joint to the mated surfaces of two materials that are relatively transparent to the laser beam. For example, carbon black increases absorption of the laser beam. There can be some unintended consequences of using these absorbing additives. Increasing the concentration of carbon black in a polymer can decrease the depth of heating and increase the peak temperature at the weld joint. Surface damage can occur if the concentration of carbon black becomes excessive.
Some additives such as the highly selective materials used in the Clearweld process are applied only to the mating surfaces between the plastics to be joined. Some of the chemicals such as cyanines only absorb in a narrow wavelength band centered around 785 nm. This methodology initially was applied only to plastics, but has recently been applied to composites such as carbon fiber reinforced PEEK.
Other additives called clarifiers can do the opposite of carbon black by increasing laser beam transmission by reducing crystallinity in polymers.
Despite the fact that both pigments and dyes can both add color to a polymer, they behave differently. A dye is soluble in a polymer, whereas a pigment is not.
Welding technique comparisons.
Contour Welding (CW) vs quasi-simultaneous (QS).
During TTIr, although it takes more energy per unit length to achieve fusion with QS than with CW, QS offers the advantage of achieving higher weld strength and weldability of low transmissive materials such as continuous glass fiber thermoplastics. Greater strength is imparted because full fusion is achieved without damaging the surface of the transparent material.
Electromagnetic welding.
Electromagnetic welding is capable of welding complex parts with also the possibility of reopening welds for replacement or repair. To achieve good welds the design of the coil and implant is important for uniform heating.
Implant resistance welding.
Implant resistance welding can be a low cost solution for welding parts that are flat or with curved surfaces. The heating element used is often a metal mesh or carbon strips, which provides uniform heating. However, advanced thermoplastic composites that contain conductive fibers can’t be used due to unwanted power leakages.
Implant induction welding.
Induction welding uses a implant or susceptor that is placed at the weld interface and embedded with conductive material such as metal or carbon fibers. An induction coil is then place near the weld joint, which induces a current in embedded in the material used to generate heat. When welding carbon fiber, carbon and graphite fiber mats with higher electrical resistance are used to concentrate the heat at the weld interface. This has the ability to weld complex geometry structures with great weld strength.
Challenges of welding advanced thermoplastic composites.
The heat generated during welding thermoplastic composite, induces residual stresses in the joint. These stresses can greatly reduce the strength and performance of the part. Upon cooling from welding the matrix and fibers will have different coefficients of thermal expansion, which introduces the residual stress. Things such as heat input, cooling rates, volume fraction of the fibers, and matrix material will influence the residual stress. Another important factor to consider is the orientation of the fibers. During the molten state of welding, fibers can reorient themselves in a manner that reduces weld strength.


Flexibility (engineering)

Flexibility is used as an attribute of various types of systems. In the field of engineering systems design, it refers to designs that can adapt when external changes occur. Flexibility has been defined differently in many fields of engineering, architecture, biology, economics, etc. In the context of engineering design one can define flexibility as the ability of a system to respond to potential internal or external changes affecting its value delivery, in a timely and cost-effective manner. Thus, flexibility for an engineering system is the ease with which the system can respond to uncertainty in a manner to sustain or increase its value delivery. Uncertainty is a key element in the definition of flexibility. Uncertainty can create both risks and opportunities in a system, and it is with the existence of uncertainty that flexibility becomes valuable.
Flexible Manufacturing System.
Flexibility has been especially thoroughly studied for manufacturing systems. For manufacturing science eleven different classes of flexibility have been identified [Browne, 1984], [Sethi and Sethi, 1990]:
These definitions yield under current conditions of the system and that no major setups are conducted or investments are made (except "expansion flexibility"). Many of the flexibility types are linked to each other; increasing one flexibility type also increases another. But in some cases tradeoffs between two flexibility types are needed.


Zhuhai Zhongfu

Zhuhai Zhongfu(珠海中富) Enterprise Co., Ltd. engages in the production and supply of PET bottles in China. It offers PET bottles for soft drinks, mineral water, distilled water, tea, and beer. The company's products also include bottle labels, film, and packing paper boxes. Zhuhai Zhongfu Enterprise Co., Ltd. is based in Zhuhai city, Guangdong province, China.
Zhuhai Zhongfu Enterprises Co. has been listed on the Shenzhen market since 1996.
Ownership.
CVC Capital Partners acquired a 29% stake in the company in 2007, paying $US225 million. This made CVC the largest single shareholder in the company.
Operations.
The company has operations throughout China and produces approximately 12 billion PET bottles a year.


Edwards Manufacturing Company

Edwards Manufacturing Company is a business in Albert Lea, Minnesota that manufactures Hydraulic Ironworkers.
History.
Manufacturing since 1875 Edwards began with road graders, and other manufacturing equipment such as the stump puller, Manual Shears, and Intake Grates.
Ironworkers.
Edwards Manufacturing Company manufactures Ironworkers and hydraulic equipment. Ironworkers are machines that speed up fabrication by punching and shearing opposed to drilling or using a saw. Edwards Ironworkers can have a Hydraulic Accessory Pack that allows separate machinery to plug into the Ironworker and use the Ironworker's hydraulic power. Edwards Manufacturing Company has a line of 12 ironworkers and 5 Hydraulic Accessories as of 2015.


Chollima-321

The Chollima-321 (Korean: 천리마 -321) is a North Korean trolleybus with battery power built by the Pyongyang Trolley Bus Factory. The name 'Chollima' refers to a myth about a winged horse that has since been adopted as the name of North Korea's Stakhanovite movement. The production of the Chollima-321 production replaced the Chollima-091 articulated trolleybus, due to the need to replace older Chollima-961, -951, Ikarus and Karosa bus based trolleybuses. The trolleybus features on a 50 won stamp.
In Japanese sources, it is called the Mallima-312.
Design.
The new trolleybus was first tested at night, with Kim Jong-un onboard, which had become a tradition for the testing of new modes of public transport. Before that, Kim Jong-un had visited the trolleybus factory, confirming the specifications of the trolleybus, such as the door width. The vehicle that he had ridden on would be numbered 483, in honour of the route he had taken, and the date on which he had tested it, August 3. The production vehicles differ that there is an additional blinker above the headlights, different lights on the rear and a ladder to the roof at the rear. The first seat is reserved for 'heroes'.
The trolleybus has a digital dashboard that monitors the overhead wire voltage, speed and battery voltage. It features a TV manufactured by Potonggang Electronics Factory. Like the Chollima-316, it has LED indicators for the route on front and rear, but the Chollima-321 also has one inside. The vehicle has no air conditioner. A new type of motor, which is more efficient than previous models was introduced on this trolleybus.
This model demonstrated that the trolleybus factory had mastered the use of plastic moulding, which was reported as achieved through CNC machines and plasma cutters. It is claimed that almost all parts are built at the factory, which after its refurbishment completed in early 2018, featured a full assembly line for trolleybuses, from framing to painting of the vehicle, with the plating of trolleybuses being automated. A new production process of curved glass was reportedly created for the use in electric public transport. Other production processes that were upgraded for its production included induction furnaces and heating furnaces, used for forging of parts.
Up until January 2020, it was reported 'more than 100' trolleybuses have been manufactured in recent years, and that despite shortages in 2019, the production was pushed ahead.
The design of the Chollima-321 has been displayed at the national industrial design exhibition in celebration of the 75th year anniversary of the founding of the Workers' Party of Korea. Its design has inspired other factories, such as the Chongjin Bus Factory, which serially produced 20 new trolleybuses in a design clearly inspired by the Chollima-321. Other similar models have been built in Hamhung and Pyongsong. The design and colour scheme of the trolleybus is similar to the 'Thongil' tram that was manufactured at the same time.
Service.
There are currently 42 known Chollima-321 trolleybuses known to be in operation. Other vehicles, such as the trolleybuses in Chongjin are a completely different model, named 'Jipsan'.


Spread tow fabric

Spread tow fabric (stf) is a type of lightweight fabric. Its production involves the steps of spreading a tow in thin and flat uni-directional tape (Spread Tow Tape, STT), and weaving the tapes to a Spread Tow Fabric. This technique increases the mechanical properties of the material and is also used to reduce weight on composites. Manufacturers of Spread Tow Tapes include Oxeon AB, Teknomax Corp., Harmoni Industry Inc., Sakaiovex.
Technique.
The spread tow technique, to weave with tapes instead of tows, tape weaving technology, was invented by Dr. Nandan Khokar in 1995. The theory behind Spread Tow Fabric is quite simple, by arranging the fibres in the woven structure in the straightest orientation possible the fibre properties are used in the most effective way to carry load, both in tensile and compression.
STF offers high versatility as it overcomes the limitations of traditional woven fabrics produced using tows. The flatness of STF, which comes from near absence of crimp, significantly reduces accumulation of matrix at the interlacing points and thereby the dead weight of the final composite material. This not only reduces the weight of the final composite material product but also eliminates the print-through defects associated with post curing of the undesired matrix accumulation.
Although the technique is based on the same principles, the spreading of the tow can be made in different way, for example using water or air.
Uses.
Spread Tow Fabric offers the advantages of relatively lower crimp, increased smoothness and less-pronounced crossover defects. As a greater number of filaments are exposed in STF they also present correspondingly improved wetting ability.
Additionally, the STF offers improved mechanical performance, thinness, draping ability and even different aesthetics compared with those produced using 1k – 6k tows.
Spread Tow Fabric is often produced with carbon fiber and is widely used in the composites industry in a number of applications.
Spread tow reinforcements (str) are reinforcements made using spread tow material, fabric or UD tapes, which is new category of composite reinforcements.


Photochemical machining

Photochemical machining (PCM), also known as photochemical milling or photo etching, is a chemical milling process used to fabricate sheet metal components using a photoresist and etchants to corrosively machine away selected areas. This process emerged in the 1960s as an offshoot of the printed circuit board industry. Photo etching can produce highly complex parts with very fine detail accurately and economically.
This process can offer economical alternatives to stamping, punching, laser or water jet cutting, or wire electrical discharge machining (EDM) for thin gauge precision parts. The tooling is inexpensive and quickly produced. This makes the process useful for prototyping and allows for easy changes in mass production. It maintains dimensional tolerances and does not create burrs or sharp edges. It can make a part in hours after receiving the drawing.
PCM can be used on virtually any commercially available metal or alloy, of any hardness. It is limited to materials with a thickness of . Metals include aluminium, brass, copper, inconel, manganese, nickel, silver, steel, stainless steel, zinc and titanium.
Photochemical machining is a form of photo engraving, and a similar process in microfabrication is called photolithography.
Process.
The process starts by printing the shape of the part onto optically clear and dimensionally stable photographic film. The "phototool" consists of two sheets of this film showing negative images of the parts (meaning that the area that will become the parts is clear and all of the areas to be etched are black). The two sheets are optically and mechanically registered to form the top and bottom halves of the tool.
The metal sheets are cut to size, cleaned and then laminated on both sides with a UV-sensitive photoresist. The coated metal is placed between the two sheets of the phototool and a vacuum is drawn to ensure intimate contact between the phototool and the metal plate. The plate is then exposed in UV light that allows the areas of resist that are in the clear sections of the film to be hardened. After exposure, the plate is "developed", washing away the unexposed resist and leaving the areas to be etched unprotected.
The etching line is a multi-chambered machine that has driven-wheel conveyors to move the plates and arrays of spray nozzles above and below the plates. The etchant is typically an aqueous solution of acid, frequently ferric chloride, that is heated and directed under pressure to both sides of the plate. The etchant reacts with the unprotected metal essentially corroding it away fairly quickly. After neutralizing and rinsing, the remaining resist is removed and the sheet of parts is cleaned and dried.
Applications.
Thin gauge (under ) parts in a broad range of alloys are candidates for photo etching.
Industrial applications include fine screens and meshes, apertures and masks, battery grids, fuel cell components, sensors, springs, pressure membranes, heat sinks, flexible heating elements, RF and microwave circuits and components, semiconductor leadframes, motor and transformer laminations, metal gaskets and seals, shields and retainers, electrical contacts, encoders and light choppers, EMI/RFI shields, jewelry and washers.
Economics.
Phototooling is quick and inexpensive to produce. Most phototools costs less than $350 and can be produced in two days or less. Unlike "hard" tools, such as stamping and punching dies, phototools are exposed only to light and therefore do not suffer wear. Due to the cost of hard tooling for stamping and fine blanking, significant volume is required to justify the expense. Some parts, such as semiconductor leadframes, are so complex and fragile that, despite volumes in the millions of pieces, they can only be produced by photo etching.
In PCM, the unit of labor is the sheet. Therefore, it is most economical to plan the largest sheet size possible consistent with the size and dimensional tolerances of the part. The more parts per sheet the lower the unit labor cost per part.
Material thickness affects costs as a function of the length of time to etch through. Most alloys etch at rates between of depth per minute per side.
In general, steel, copper or aluminium workpieces with a thicknesses up to , part costs will approximate $0.15–0.20 per square inch. As the geometry of the part becomes more complex, photochemical machining gains greater economic advantage over sequential processes such as CNC punching, laser or water-jet cutting, and electrical discharge machining.


Cladding (metalworking)

Cladding is the bonding together of dissimilar metals. It is different from fusion welding or gluing as a method to fasten the metals together. Cladding is often achieved by extruding two metals through a die as well as pressing or rolling sheets together under high pressure.
The United States Mint uses cladding to manufacture coins from different metals. This allows a cheaper metal to be used as a filler. For example, dimes and quarters struck since 1965 have cores made from pure copper, with a clad layer consisting of 75% copper and 25% nickel added during production. Half dollars struck from 1965 to 1969 for circulation and in 1970 for collectors also incorporated cladding, albeit in the case of those coins, the core was a mixture of 20.9% silver and 79.1% copper, and its clad layer was 80% silver and 20% copper. Half dollars struck since 1971 are produced identically to the dimes and quarters.
Laser cladding is an additive manufacturing approach for metal coatings or precise piece restorations by using high power multi-mode optical fiber laser.
Roll bonding.
In roll bonding, two or more layers of different metals are thoroughly cleaned and passed through a pair of rollers under sufficient pressure to bond the layers. The pressure is high enough to deform the metals and reduce the combined thickness of the clad material. Heat may be applied, especially when metals are not ductile enough. As an example of application, bonding of the sheets can be controlled by painting a pattern on one sheet; only the bare metal surfaces bond, and the un-bonded portion can be inflated if the sheet is heated and the coating vaporizes. This is used to make heat exchangers for refrigeration equipment.
Explosive welding.
In explosive welding, the pressure to bond the two layers is provided by detonation of a sheet of chemical explosive. No heat-affected zone is produced in the bond between metals. The explosion propagates across the sheet, which tends to expel impurities and oxides from between the sheets. Pieces up to 4 x 16 metres can be manufactured. The process is useful for cladding metal sheets with a corrosion-resistant layer.
Laser cladding.
"Laser cladding" is a method of depositing material by which a powdered or wire feedstock material is melted and consolidated by use of a laser in order to coat part of a substrate or fabricate a near-net shape part (additive manufacturing technology) .
It is often used to improve mechanical properties or increase corrosion resistance, repair worn out parts, and fabricate metal matrix composites. Surface material may be laser cladded directly onto a highly stressed component, i.e. to make a self-lubricating surface. However, such a modification requires further industrialization of the cladding process to adapt it for efficient mass production. Further research on the detailed effects from surface topography, material composition of the laser cladded material and the composition of the additive package in the lubricants on the tribological properties and performance are preferably studied with tribometric testing.
Process.
A laser is used to melt metallic powder dropped on a substrate to be coated. The melted metal forms a pool on the substrate; moving the substrate allows the melt pool to solidify in a track of solid metal. Some processes involve moving the laser and powder nozzle assembly over a stationary substrate to produce solidified tracks. The motion of the substrate is guided by a CAM system which interpolates solid objects into a set of tracks, thus producing the desired part at the end of the trajectory.
Automatic laser cladding machines are the subject of ongoing research and development. Many of the process parameters must be manually set, such as laser power, laser focal point, substrate velocity, powder injection rate, etc., and thus require the attention of a specialized technician to ensure proper results. By use of sensors to monitor the deposited track height and width, metallurgical properties , and temperature, constant observation from a technician is no longer required to produce a final product. Further research has been directed to forward processing where system parameters are developed around specific metallurgical properties for user defined applications (such as microstructure, internal stresses, dilution zone gradients, and clad contact angle).


Apple Monitor II

The Apple Monitor II is a CRT-based green monochrome 12-inch monitor manufactured by Sanyo for Apple Computer; for the Apple II personal computer family. Apple did not introduce the monitor until halfway through the lifespan of the II series. The business-oriented Apple III had its own Apple Monitor III long before. Many home users of Apple II computers used their televisions as computer monitors before the Monitor II was released. It featured an inner vertical-swiveling frame. This allowed users to adjust the viewing angle up or down to suit their taste without the addition of a tilt-and-swivel device. The Monitor II was widely adjustable for the time, including adjustments for the size and location of the image on the screen. These adjustments had a very small influence on the picture, however, much to the dislike of some users. The Monitor II was designed for the Apple II+, but was used widely throughout the Apple II product line, most recognizably on the Apple IIe.


DYE Precision

DYE Precision, also known as simply DYE, is a paintball equipment manufacturing company and a well known Numerical control (CNC) manufacturing company operated under the brand DYE CNC based in California. Dave Dehaan started the company by producing barrels for paintball markers, using his garage as a workshop. He supplied barrels to the California Ironmen and Team Avalanche, who at that time were two of the most dominant teams in Professional paintball. From these humble beginnings, DYE went on to become an International concern that went on to manufacture an extensive range of paintball markers, loaders, playing & casual clothing, protective gear, goggles and luggage and created an economy focused offshoot brand Proto Paintball. Their range of products is typically updated each year. In 2005, the company was praised as one of the industry's largest paintball manufacturers. The company has offices in London, Taiwan and Germany.
Markers.
DYE markers are considered to be high end tournament level markers and have been used professionally since their inception. Their most notable marker the Matrix line is a spool valve operated electropneumatic marker that featured smooth "flowing" milling to the aluminum body and a soft shot profile. Many notable professional teams have used DYE markers including Los Angeles Ironmen, Tampa Bay Damage and Red Legion.
History.
DYE Precision was founded by Dave and Rhonda DeHaan in 1994. DYE stands for Dave "Youngblood" Enterprises.
In 2006, DYE Precision sponsored a team, XXTIONEER, at the 2006 Paintball World Cup Asia.
In March 2009, DYE Precision manufactured the Baltimore Trauma with 2009 Mid-Atlantic Open jerseys.
In March 2010, the company allowed teams at the 2010 Paintball Sports Promotions World Cup to experience the new 2010 models free of charge. In April 2010, DYE Precision manufactured the jerseys for professional paintball team Portland Naughty Dogs. and later presented them with a limited special edition Naughty Dogs NT paintball gun. That same month, DYE Precision co-hosted the National Collegiate Paintball Association tournament in Central Florida.
In January 2011, DYE Precision signed a multi-year agreement with professional paintball team Chattanooga CEP.
In October 2012, DYE Precision signed a multi-year agreement with Ukrainian professional paintball team Hulk Kiev
In November 2012, the company purchased Pro-Tec, a helmet manufacturing company, from apparel and sports equipment company Vans for an undisclosed amount.
In December 2015, DYE Precision sold off Pro-Tec, a helmet manufacturing company, to Bravo Sports, a sporting goods and manufacturing brand for an undisclosed amount.