Deep drawing

Deep drawing is a sheet metal forming process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch. It is thus a shape transformation process with material retention. The process is considered "deep" drawing when the depth of the drawn part exceeds its diameter. This is achieved by redrawing the part through a series of dies.
The flange region (sheet metal in the die shoulder area) experiences a radial drawing stress and a tangential compressive stress due to the material retention property. These compressive stresses (hoop stresses) result in flange wrinkles (wrinkles of the first order). Wrinkles can be prevented by using a blank holder, the function of which is to facilitate controlled material flow into the die radius. Deep drawing presses, especially in the Aerospace and Medical industries, require unparalleled accuracy and precision. Sheet hydroforming presses do complex draw work. Bed size, tonnage, stroke, speed, and more can be tailored to your specific draw forming application.
Process.
The total drawing load consists of the ideal forming load and an additional component to compensate for friction in the contacting areas of the flange region and bending forces as well as unbending forces at the die radius. The forming load is transferred from the punch radius through the drawn part wall into the deformation region (sheet metal flange). In the drawn part wall, which is in contact with the punch, the hoop strain is zero whereby the plane strain condition is reached. In reality, mostly the strain condition is only approximately plane. Due to tensile forces acting in the part wall, wall thinning is prominent and results in an uneven part wall thickness, such that the part wall thickness is lowest at the point where the part wall loses contact with the punch, i.e., at the punch radius.
The thinnest part thickness determines the maximum stress that can be transferred to the deformation zone. Due to material volume constancy, the flange thickens and results in blank holder contact at the outer boundary rather than on the entire surface. The maximum stress that can be safely transferred from the punch to the blank sets a limit on the maximum blank size (initial blank diameter in the case of rotationally symmetrical blanks). An indicator of material formability is the limiting drawing ratio (LDR), defined as the ratio of the maximum blank diameter that can be safely drawn into a cup without flange to the punch diameter. Determination of the LDR for complex components is difficult and hence the part is inspected for critical areas for which an approximation is possible. During severe deep drawing the material work hardens and it may be necessary to anneal the parts in controlled atmosphere ovens to restore the original elasticity of the material.
Commercial applications of this metal shaping process often involve complex geometries with straight sides and radii. In such a case, the term stamping is used in order to distinguish between the deep drawing (radial tension-tangential compression) and stretch-and-bend (along the straight sides) components. Deep drawing is always accompanied by other forming techniques within the press. These other forming methods include:
Often components are partially deep drawn in order to create a series of diameters throughout the component (as in the image of the deep draw line). It common use to consider this process as a cost saving alternative to turned parts which require much more raw material.
The sequence of deep drawn components is referred to as a "deep draw line". The numbers of components that form the deep draw line is given by the quantity of "stations" available in the press. In the case of mechanical presses this is determined by the number of cams on the top shaft.
For high precision mass productions, it is always advisable to use a transfer press also known as eyelet press. The advantage of this type of press, in respect to conventional progressive presses, is that the parts are transferred from one die to the next by means of so-called "fingers". Not only do the fingers transfer the parts but they also guide the component during the process. This allows parts to be drawn to the deepest depths with the tightest tolerances.
Other types of presses:
Variations.
Deep drawing has been classified into "conventional" and "unconventional" deep drawing. The main aim of any unconventional deep drawing process is to extend the formability limits of the process. Some of the unconventional processes include hydromechanical deep drawing, Hydroform process, Aquadraw process, Guerin process, Marform process and the hydraulic deep drawing process to name a few.
The Marform process, for example, operates using the principle of rubber pad forming techniques. Deep-recessed parts with either vertical or sloped walls can be formed. In this type of forming, the die rig employs a rubber pad as one tool half and a solid tool half, similar to the die in a conventional die set, to form a component into its final shape. Dies are made of cast light alloys and the rubber pad is 1.5-2 times thicker than the component to be formed. For Marforming, single-action presses are equipped with die cushions and blank holders. The blank is held against the rubber pad by a blank holder, through which a punch is acting as in conventional deep drawing. It is a double-acting apparatus: at first the ram slides down, then the blank holder moves: this feature allows it to perform deep drawings (30-40% transverse dimension) with no wrinkles.
Industrial uses of deep drawing processes include automotive body and structural parts, aircraft components, utensils and white goods. Complex parts are normally formed using progressive dies in a single forming press or by using a press line.
Workpiece materials and power requirements.
Softer materials are much easier to deform and therefore require less force to draw. The following is a table demonstrating the draw force to percent reduction of commonly used materials.
Tool materials.
Punches and dies are typically made of tool steel, however cheaper (but softer) carbon steel is sometimes used in less severe applications. It is also common to see cemented carbides used where high wear and abrasive resistance is present.
Alloy steels are normally used for the ejector system to kick the part out and in durable and heat resistant blankholders.
Lubrication and cooling.
Lubricants are used to reduce friction between the working material and the punch and die. They also aid in removing the part from the punch. Some examples of lubricants used in drawing operations are heavy-duty emulsions, phosphates, white lead, and wax films. Plastic films covering both sides of the part while used with a lubricant will leave the part with a fine surface.


Incremental sheet forming

Incremental sheet forming (or ISF, also known as Single Point Forming) is a sheet metal forming technique where a sheet is formed into the final workpiece by a series of small incremental deformations. However, studies have shown that it can be applied to polymer and composite sheets too. Generally, the sheet is formed by a round tipped tool, typically 5 to 20mm in diameter. The tool, which can be attached to a CNC machine, a robot arm or similar, indents into the sheet by about 1 mm and follows a contour for the desired part. It then indents further and draws the next contour for the part into the sheet and continues to do this until the full part is formed. ISF can be divided into variants depending on the number of contact points between tool, sheet and die (in case there is any). The term Single Point Incremental Forming (SPIF) is used when the opposite side of the sheet is supported by a faceplate and Two Point Incremental Forming (TPIF) when a full or partial die supports the sheet.
Types.
Single-point incremental forming (SPIF) and double-sided incremental forming (DSIF) are the two variants of the IF process. In the DSIF process, two tools are used to form the sheet on either side, while the SPIF process only uses a tool on one side of the sheet. Thus, a component having features on either side of the sheet, e.g., an inverted cone can be effectively formed by the DSIF process.
Advantages over conventional sheet metal forming.
Because the process can be controlled entirely by CNC processes no die is required as is in traditional sheet metal forming. The elimination of the die in the manufacturing process reduces the cost per piece and decreases turnaround time for low production runs because the need to manufacture a die is eliminated. However, for high production runs the time and cost to produce a die is absorbed by the higher per piece speed and lower per piece cost.
Several authors recognize that the formability of metal materials under the localized deformation imposed by incremental forming is better than in conventional deep drawing. In contrast, there is a loss of accuracy with the ISF process.
Implementation.
The ISF process is generally implemented by clamping a sheet in the XY plane, which is free to move along the Z axis. The tool moves in the XY plane and is coordinated with movements in the Z axis to create the desired part. It is often convenient to retrofit a CNC milling machine to accommodate the process. Spherical, flat-bottomed, and parabolic tool profiles can be used to achieve differing surface finishes and forming limits.
The machine employs a combination of stretch forming by drawing the sheet incrementally down over a die, with the CNC tool approach described above. This is said to produce a more even distribution of thickness of the material. The process is well suited to one-off manufacture though difficulties in simulating the process mean that toolpaths are complex and time-consuming to determine.
Ford Motor Company has recently released Ford Freeform Fabrication Technology, a two-point incremental sheet-forming technique being implemented in the rapid prototyping of automotive parts. Complex shapes such as the human face and cranial implants have been manufactured successfully using this manufacturing process. Advances in the technology are expected to increase adoption in the near future by other sheet metal-reliant manufacturers.
Applications.
Incremental forming (IF) is a recent manufacturing process having a wide range of applications in the following areas.
List of process parameters.
The mechanics of the process is influenced by many parameters, including:
Current research.
Research is underway at several universities. The most common implementation is to outfit a traditional milling machine with the spherical tool used in the ISF process. Key research areas include


GKD Legend

The GKD LEGEND is a light-weight performance sports car manufactured by British company GKD Sports Cars, based in Boughton Monchelsea, near Maidstone with workshops at Lenham. The LEGEND is available in component form, or fully built. It was the first seven inspired car on the market using BMW E36/46 running gear.
History.
The GKD LEGEND was a byproduct of the work to convert the GKD EVOLUTION to BMW donor parts. Creator Peter Lathrope saw a gap in the market for a BMW based seven and developed the LEGEND. After its first show preview at Exeter kit car show the press hailed the car as "the next big thing" in the kit car market as most of the Lotus Seven Style cars are still Ford Sierra based. After the success of the initial Legend GKD Sports Cars bridged the gap between the Legend and the Evolution by introducing a new variant known as the Legend six. This model is a slightly longer chassis to accommodate the BMW straight 6 engine and running gear but still keeping the classic 7 style.
Car components.
The car uses a donor pack from a BMW 3 Series. The donor pack includes differential, half-shafts, brakes, steering column and lower steering shaft and if required, engine and gearbox. The chassis comes with BMW engine mounts already welded to the chassis to ease fitment.
Kits start at around £2,995, with an estimated build price from £8,000 (as of late 2008).
Fully built cars are also supplied to foreign markets, countering crash test requirements. Prices start at around £10,500, with the donor pack left to the customer to source. Or GKD can supply all the donor pack components to order.
The body shell is made from GRP fibreglass, with a bespoke chassis housing the engine and suspension.
Example cars.
The LEGEND can utilise most engines. The chart below indicates performance with a BMW E46 1.8 with different states of tune. Also including the Legend six with the E46 M3 engine and running gear


Sigrity

Sigrity, acquired by Cadence Design Systems in 2012 for $80M, supplies software for IC package physical design and for analyzing power integrity, signal integrity and design stage electromagnetic interference (EMI). Analysis is performed on chips, IC packages and printed circuit boards.
Overview.
Sigrity began operations with a 1997 award from the National Science Foundation for simulation using electromagnetic computation techniques targeting electronic structures with hybrid solver techniques. The IC package physical layout product line was acquired from Synopsys in 2006.
The 2017 revision of Cadence’s Sigrity product introduces several features specifically designed to speed up PCB power and signal integrity signoff. In 2016, Cadence expanded the portfolio with an upgraded serial link analysis flow including an IBIS-AMI modeling-building technology, USB 3.1 (Gen 2) compliance kit, and cut-and-stitch model extraction technology to segment long serial links into sections that should be modeled using 3D full-wave and sections that can be modeled using hybrid extraction technology. In 2015, Cadence released the Sigrity Parallel Computing 4-pack which enabled efficient product creation with 3X speedup in signoff-accurate PCB extraction, an updated power-aware system signal integrity (SI) feature which supports LPDDR4 analysis with full JEDEC compliance checking, and flexible licensing options.


Mitchell Electronics

Mitchell Electronics Incorporated, founded in 1979, is a manufacturer of equipment to test and run servomotors, encoders and resolvers as well as various third-party electronic devices. Corporate headquarters are located in Athens, Ohio, which is also where manufacturing takes place. The company is an associate member of the Electrical Apparatus Service Association (EASA), an international electromechanical trade organization.
Company history.
Mitchell Electronics began in 1979 by providing custom designed industrial electronic systems to the motion control. By 1983 the company had progressed to offering standard computer based industrial products to end users and to original equipment manufacturers as components in their products and ten years later began offering encoder test equipment. In 1999 the company began offering a suite of hardware and Windows-based software to designed to test additional types of encoders as well as resolvers and other servo feedback devices.
In 2001 the company introduced a line of equipment designed to provide repair shops and plant maintenance personnel the ability to test run many types of servo motors with one common drive device. A patent was later issued to the company for "an apparatus that allows a non-standard brushless motor to be driven with a standard drive amplifier."
Equipment and Services.
Mitchell Electronics' products include the TI-3000 line of servomotor run-rest equipment, TI-4000EX (formerly PulsePro) line of encoder test equipment, TI-5000EX (formerly TI-5000) line of PC based servo feedback test equipment and software and the TI-7000 line of servo feedback field test equipment. Most major motor and feedback manufacturer's devices are supported by Mitchell Electronics equipment, which is widely used in the motor and feedback repair field and other industrial applications, such as CNC machining and robotics, around the world. Notable manufacturing applications include use by Ford, General Mills, and Sturm Ruger.
The company additionally provides consulting, hardware and software development and manufacturing services to various third party distributors and OEM manufacturers, generally also in the electronics field, such as Avtron and certain divisions of Danaher. Mitchell Electronics equipment is also used in servomotor operation and service training courses.


Lens board

A lens board or lensboard is a photographic part used for securing a lens to the front standard of a large format view camera. The lens board itself is usually flat, square, and made of metal (most commonly aluminum), wood, or plastic. The lens board will have a hole of various diameters drilled dead center on the board. A lens board typically varies between 1 and 4 millimeters in thickness. The overall size and shape of the lens board depends on the brand of camera and film format used. Some cameras will use 2 to 4 screws to secure the lens board to the front standard of the view camera, most commonly however, the lens board will be secured by one or more locking levers or tabs to allow tool-less removal of the lens board. The rear surface of a lens board is usually painted matte black to keep light entering the camera through the lens during exposure from reflecting off the surface and interfering with the projected image.
While most lens boards are flat, some are recessed to accommodate wider focal length lenses which must be positioned closer to the film plane. A recessed lens board effectively reduces the flange focal distance of a camera.
Sizes.
Depending on the size and focal length of a particular lens, a certain diameter of hole is drilled in the center of the lens board to accommodate the shutter assembly. Lens boards are typically available pre-drilled by the camera manufacturer, however, if no replacement lens board is available from a camera manufacturer, then one can be custom fabricated by a machinist.
Nearly all large format leaf shutters made since the 1990s are manufactured by the Nidec Copal Corporation, therefore the diameter of hole drilled is commonly referred to as the ‘Copal Number’.
The Copal sizes are as follows:
The origin Compur/Compound sizes are as follows:
Lens mounting.
Lenses are fitted to a lens board by placing the shutter assembly through the front of the board and securing the shutter assembly by threading a locknut to rear of the shutter. A front lens element will thread onto the mounted shutter and if necessary, a second lens element will thread onto the rear of the mounted shutter. This procedure can be accomplished by a camera technician, or by an end-user with the appropriate tools.
Other uses.
Lens boards are used in photographic enlargers to secure an enlarging lens to the focus stage of the device.
Similar to large format photographic view cameras, a lens board is utilized by some reprographic cameras in the printing industry.
Lens boards may also be used by some medical and scientific imaging devices.


Maverick Technologies

Maverick Technologies is an industrial automation, enterprise integration, operational consulting and sustaining services provider. The company has over 500 employees and 18 U.S. locations and operations worldwide and is the largest independent systems integrator in North America.
History.
In 1989, Paul Galeski founded MAGNUM Technologies. In 1995, Inc. Magazine cited MAGNUM Technologies as one of the nation's fastest growing companies. In 1997, MAGNUM Technologies was sold to General Electric, where it became a GE Industrial Systems Division subsidiary. Paul Galeski continued to serve as President of the GE Industrial Systems Division until he left GE in early 1999.
Later that year, Paul Galeski founded MAVERICK Technologies and acquired Software Architects, also an Inc. 500 company. Between 2002 and 2004, MAVERICK Technologies acquired RHES Inc. and Professional Maintenance Consultants. In 2005, they acquired GEAS (General Electric Automation Services) and CF Picou, Inc. Between 2006 and 2009, MAVERICK Technologies acquired LaPlace Technologies, Mission Controls and Program4 Engineering.
MAVERICK Technologies partnered with MPE Industrial Automation Europe and MPE Industrial Automation Asia to form the Global System Integrators Alliance (GSIA), a partnership that connects its members to more than 30 locations and 700 professionals worldwide. MAVERICK began international operations in the Netherlands and Thailand in 2008 and Singapore in 2009.
As of 2011, MAVERICK Technologies had completed 10,000 projects in 45 countries on six continents, employs over 500 people globally and has been listed as one of the Inc. 500 fastest growing companies five times.
In 2016, MAVERICK Technologies was acquired by Rockwell Automation.
Services.
MAVERICK Technologies provides industrial automation, enterprise integration and strategic manufacturing solutions to manufacturing and processing industries worldwide.
It serves biofuel, chemical and petrochemical, upstream and downstream oil and gas, bakery, beverage, confectionery, dairy, protein, consumer packaged goods, high-tech manufacturing, life sciences, and power and utilities industries through a network of employees and international partners.
Industrial automation.
MAVERICK’s industrial automation services comprise automation solutions including automation engineering, process automation, industrial automation integration, regulatory-compliant systems and services and distributed control system migration; field services, which include construction management, technician/calibration, outage services and planning, maintenance and installation; and advanced process control services.
Enterprise integration.
MAVERICK’s enterprise integration services comprise manufacturing IT services, including demand planning, production planning and scheduling, sourcing and procurement, logistics and distribution, manufacturing execution/production management, manufacturing intelligence and quality management; and business solutions, which include Microsoft Dynamics AX, customer relationship management (CRM), enterprise manufacturing intelligence (EMI) and enterprise application integration (EAI).
Strategic manufacturing solutions.
MAVERICK’s strategic manufacturing solutions comprise sustaining services, including industrial security solutions; and offers operational consulting services, which include operational strategy, productivity improvements, energy optimization and safety.
Paul Galeski.
Paul Galeski, CEO and President of MAVERICK Technologies, was named one of Fast Forward's '40 under 40,' and St. Louis Business Journal ‘Who’s Who in Technology,’ a listing of top young St. Louis area executives. In 2002, Galeski was awarded the Illinois Entrepreneur of the Year and later elected to an International Society of Automation (ISA) Fellow appointment.
Galeski holds a bachelor's degree in electrical engineering from Southern Illinois University, where he is a member of the inaugural class of the SIUE Alumni Hall of Fame and sponsor of the MAVERICK Technologies LLC Scholarship in Engineering. He is a graduate of the GE executive management school and the Harvard Business School President's Program. He is also involved in expert witness testimony, and is a contributing author to Aspatore Books' Inside the Minds, a series of publications that examine C-level business intelligence.


Tamiya connector

A Tamiya connector is a type of DC power connector, commonly used on radio-controlled model vehicle battery packs, drones and chargers. They are also commonly used on airsoft guns. The connector was designed by Japanese manufacturer Tamiya Corporation.
The connector is still available from connector manufacturers such as Molex. The following connectors are compatible with the Tamiya connectors: 19-09-1029 with crimp 02-09-1119 and 19-09-2029 with crimp 02-09-2116.
Wiring.
The usual wiring has the positive (red) wire running to the terminal with a square profile, and the negative (black) wire running to the half-circle, half-square terminal. This is true for both genders of connector. The female sockets are in a male housing and the male pins are in a female housing. The male pins (female housing) connector is usually on the battery side.
In electrical and electronics engineering, the convention is that gender refers to the metal contact parts of a connector in order to avoid ambiguity. A large number of hobbyist retailers selling these connectors refer to the gender of the plastic housing, which is against convention and can lead to errors.
In some cases, Mini-Tamiya connectors are wired in reverse polarity. This is often the case with airsoft guns, where the square profile terminal is the negative terminal and the rounded terminal is the positive terminal.
Sizes.
There are two sizes of Tamiya connectors: standard and mini.
The outside dimensions of the standard connector is:
The outside dimensions of the mini connector is:
The standard Tamiya connector uses "D" cross-section sheaths for polarisation as seen in the male end above. The mini-Tamiya connector uses one square and one or two round sheaths.
Advantages.
A useful feature of the Tamiya connectors is the locking mechanism which prevents accidental disconnection.
The connector physically isolates the positive and negative wires so that the connectors remain safe to use in damp conditions. This makes them safe for use in relatively low-current applications (up to about 15 A) in dirty conditions (for example, model boats or RC cars used outdoors).


DigitalOptics Corporation

DigitalOptics Corporation (DOC) is a San Jose, California-based technology company that designs and manufactures imaging systems for smartphones. DOC’s capabilities include optical design, camera module design and manufacturing, MEMS manufacturing, and image processing algorithms.
In 2013, DOC introduced a camera module technology ( mems|cam) with a MEMS-based autofocus actuator. The technology is designed to replace voice coil motor components, while improving speed, power consumption, and precision of the autofocus function.
DigitialOptics also provides embedded image processing and computational photography algorithms, including its face beautification, face detection, and multi-focus products.
DigitalOptics Corporation operates as a wholly owned subsidiary of Xperi. DOC consists of the imaging and optics-related businesses acquired by Xperi. since 2005.


Spania GTA

Spania GTA is an automobile design and manufacturing company based in Valencia, Spain. It was founded by Domingo Ochoa, who is also the current CEO of the company.
They have designed, developed, and produced the GTA Spano in-house. The first production units were delivered to the customers in 2012, with full scale production expected in 2013.


Probe card

A probe card (commonly referred to as a DUT board) is used in automated integrated circuit testing. It is an interface between an electronic test system and a semiconductor wafer.
Use and manufacture.
A probe card or DUT board is a printed circuit board (PCB), and is the interface between the integrated circuit and a test head, which in turn attaches to automatic test equipment (ATE) (or "tester"). Typically, the probe card is mechanically docked to a Wafer testing prober and electrically connected to the ATE . Its purpose is to provide an electrical path between the test system and the circuits on the wafer, thereby permitting the testing and validation of the circuits at the wafer level, usually before they are diced and packaged. It normally comprises a PCB and some form of contact elements, usually metallic.
A semiconductor manufacturer will typically require a new probe card for each new device wafer and for device shrinks (when the manufacturer reduces the size of the device while keeping its functionality) because the probe card is effectively a custom connector that takes the universal pattern of a given tester and translates the signals to connect to electrical pads on the wafer. For testing of Dynamic random-access memory (DRAM) and Flash memory (FLASH) devices, these pads are typically made of aluminum and are 40–90  per side. Other devices may have flat pads, or raised bumps or pillars made of copper, copper alloys or many types of solders such as lead-tin, tin-silver and others.
The probe card must make good electrical contact to these pads or bumps during the testing of the device. When the testing of the device is complete, the prober will index the wafer to the next device to be tested.
Normally a probe card is inserted into a wafer prober, inside which the position of the wafer to be tested will be adjusted to ensure a precise contact between the probe card and wafer. Once the probe card and the wafer are loaded, a camera in the prober will optically locate several tips on the probe card and several marks or pads on the wafer, and using this information it will align the pads on the device under test (DUT) to the probe card contacts.
Design and types.
Probe cards are broadly classified into needle type, vertical type, and MEMS (Micro Electro-Mechanical System) type depending on shape and forms of contact elements. MEMS type is the most advanced technology currently available. The most advanced type of probe card currently can test an entire 12" wafer with one touchdown.
Probe cards or DUT boards are designed to meet both the mechanical and electrical requirements of the particular chip and the specific test equipment to be used. One type of DUT board is used for testing the individual die of a silicon wafer before they are cut free and packaged, and another type is used for testing packaged IC's.
Efficiency factors.
Probe card efficiency is affected by many factors. Perhaps the most important factor impacting probe card efficiency is the number of DUTs that can be tested in parallel. Many wafers today are still tested one device at a time. If one wafer had 1000 of these devices and the time required to test one device was 10 seconds and the time for the prober to move from one device to another device was 1 second, then to test an entire wafer would take 1000 x 11 seconds = 11,000 seconds or roughly 3 hours. If however, the probe card and the tester could test 16 devices in parallel (with 16 times the electrical connections) then the test time would be reduced by almost exactly 16 times (to about 11 minutes).
Advanced Tester Resource Enhancement (ATRE) is a powerful means of increasing the number of DUTs that can be tested by a probe card in parallel (or in one touchdown during which probe card needles remain in contact with the wafer DUTs). ATRE allows the sharing of tester resources among DUTs using active components, which have the ability to connect and disconnect DUTs from the tester resources. Without ATRE, a single tester resource (power, DC or AC signal) would normally only go directly to one DUT. However by installing ATRE-configured relays (switches) onto the probe card PCB, the tester resource can split or branch out to multiple DUTs. For example in a x4 sharing configuration, 1 power signal is fed into 4 relays whose outputs go to 4 DUTs, respectively. Then by turning each relay ON and OFF sequentially (in the case of a DUT current measurement test), the tester can test each of the 4 DUTs in turn during the same touchdown (without having to move the prober from one device to the other). Therefore a tester that has only 256 power signals will appear to have its resources expanded or enhanced so as to enable it to test 1024 DUTs in one touchdown, thanks to the 1024 onboard relays in the x4 sharing scheme implemented on the probe card. ATRE brings dramatic savings in terms of test time and cost, as it can allow a chip manufacturer or test house to validate more DUTs in one touchdown without the need to purchase a more advanced tester equipped with more resources.
Contamination issues.
Another major factor is debris that accumulates on the tips of the probe needles. Normally these are made of tungsten or tungsten/rhenium alloys or advanced palladium based alloys like PdCuAg. Some modern probe cards have contact tips manufactured by MEMS technologies.
Irrespective of the probe tip material, contamination builds up on the tips as a result of successive touchdown events (where the probe tips make physical contact with the bond pads of the die). Accumulation of debris has an adverse effect on the critical measurement of contact resistance. To return a used probe card to a contact resistance that is acceptable, the probe tips must be spotless. Cleaning can be done offline using an NWR style laser to reclaim the tips by selectively removing the contamination. Online cleaning can be used during testing to optimize the testing results within the wafer or within wafer lots.


Hybrid integrated circuit

A hybrid integrated circuit (HIC), hybrid microcircuit, hybrid circuit or simply hybrid is a miniaturized electronic circuit constructed of individual devices, such as semiconductor devices (e.g. transistors, diodes or monolithic ICs) and passive components (e.g. resistors, inductors, transformers, and capacitors), bonded to a substrate or printed circuit board (PCB). A PCB having components on a Printed Wiring Board (PWB) is not considered a true hybrid circuit according to the definition of MIL-PRF-38534.
Overview.
"Integrated circuit" as the term is currently used refers to a monolithic IC which differs notably from a HIC in that a HIC is fabricated by inter-connecting a number of components on a substrate whereas an IC's (monolithic) components are fabricated in a series of steps entirely on a single wafer which is then diced into chips. Some hybrid circuits may contain monolithic ICs, particularly Multi-chip module (MCM) hybrid circuits.
Hybrid circuits could be encapsulated in epoxy, as shown in the photo, or in military and space applications, a lid was soldered onto the package. A hybrid circuit serves as a component on a PCB in the same way as a monolithic integrated circuit; the difference between the two types of devices is in how they are constructed and manufactured. The advantage of hybrid circuits is that components which cannot be included in a monolithic IC can be used, e.g., capacitors of large value, wound components, crystals, inductors. In military and space applications, numerous integrated circuits, transistors and diodes, in their die form, would be placed on either a ceramic or beryllium substrate. Either gold or aluminum wire would be bonded from the pads of the IC, transistor, or diode to the substrate.
Thick film technology is often used as the interconnecting medium for hybrid integrated circuits. The use of screen printed thick film interconnect provides advantages of versatility over thin film although feature sizes may be larger and deposited resistors wider in tolerance. Multi-layer thick film is a technique for further improvements in integration using a screen printed insulating dielectric to ensure connections between layers are made only where required. One key advantage for the circuit designer is complete freedom in the choice of resistor value in thick film technology. Planar resistors are also screen printed and included in the thick film interconnect design. The composition and dimensions of resistors can be selected to provide the desired values. The final resistor value is determined by design and can be adjusted by laser trimming. Once the hybrid circuit is fully populated with components, fine tuning prior to final test may be achieved by active laser trimming.
Thin film technology was also employed in the 1960s. Ultra Electronics manufactured circuits using a silica glass substrate. A film of tantalum was deposited by sputtering followed by a layer of gold by evaporation. The gold layer was first etched following the application of a photoresist to form solder compatible connection pads. Resistive networks were formed, also by a photoresist and etching process. These were trimmed to a high precision by selective adonization of the film. Capacitors and semiconductors were in the form of LID (Leadless Inverted Devices) soldered to the surface by selectively heating the substrate from the underside. Completed circuits were potted in a diallyl phthalate resin. Several customized passive networks were made using these techniques as were some amplifiers and other specialized circuits. It is believed that some passive networks were used in the engine control units manufactured by Ultra Electronics for Concorde.
Some modern hybrid circuit technologies, such as LTCC-substrate hybrids, allow for embedding of components within the layers of a multi-layer substrate in addition to components placed on the surface of the substrate. This technology produces a circuit that is, to some degree, three-dimensional.
Other electronic hybrids.
In the early days of telephones, separate modules containing transformers and resistors were called hybrids or hybrid coils; they have been replaced by semiconductor integrated circuits.
In the early days of transistors the term "hybrid circuit" was used to describe circuits with both transistors and vacuum tubes; e.g., an audio amplifier with transistors used for voltage amplification followed by a vacuum tube power output stage, as suitable power transistors were not available. This usage, and the devices, are obsolete, however amplifiers that use a tube preamplifier stage coupled with a solid state output stage are still in production, and are called hybrid amplifiers in reference to this.


Geunyoung Industry

Geunyoung Industry Co, Ltd. (hangul:근영산업) is a Korean auto parts company headquartered in Nowon-Dong, Buk-Gu Daegu established in 1977. It makes automotive spare parts products, similar to Hyundai Mobis and SL Corp. The "Geunyoung Industry" CEO is brother by Yoo Deok Sool & Yoo Yeong Sool (유덕술, 유영술 형제).


Rotary wheel blow molding systems

Rotary wheel blow molding systems are used for the high-output production of a wide variety of plastic extrusion blow molded articles. Containers may be produced from small, single serve bottles to large containers up to 20-30 liters in volume - but wheel machines are often sized for the volume and dimensional demands of a specific container, and are typically dedicated to a narrow range of bottle sizes once built. Multiple parison machines, with high numbers of molds are capable of producing over one million bottles per day in some configurations.
Description.
Rotary blow molding "wheels" are targeted to the high output production of containers. They are used to produce containers from one to seven layers. View stripe and In Mold Labeling (IML) options are available in some configurations. Rotary wheels, which may contain from six to thirty molds, feature continuously extruded parisons. Revolving sets of blow molds capture the parison or parisons as they pass over the extrusion head. The revolving sets of molds are located on clamp "stations".
Rotary wheels come in different variations, including both continuous motion and indexing wheels, and vertical or horizontal variations. Wheel machines are favored for their processing ease, due to having only single (or in some cases, two) parisons, and mechanical repeatability.
In some machinery configurations, the molds take on the shape of a "pie" sector. Thus, if two or more parisons are used, each blow molded "log" has a unique length, requiring special downstream handling and trimming requirements. In other machine configurations, the molds utilize "book style" opening mechanisms, allowing multiple parisons of equal length. However, machines of this style typically have lower clamp force, limiting the available applications.
The mold close and open actuation is typically carried out through a toggle mechanism linkage that is activated during the rotational process by stationary cams. This mechanical repeatability is considered an advantage by most processors.
The method of wheel rotation is typically conducted through an electric motor with a "pinion" gear or small gear to or in mesh with a rotating "bull" gear or large gear. All utilities for blowing containers and for mold cooling are carried through the main shaft or the axle from which the wheel rotates about. These utilities include compressed air and water. Sequencing functions necessary to inflate the parison, hold the container prior to discharge and discharge are completed by mechanical actuation to pneumatic valves – resulting in a high degree of repeatability.
Advantages & disadvantages.
Very tight weight and dimensional tolerances can be obtained on wheel equipment, as the parison is captured on both ends. It is pinched in the preceding mold on the leading end, and positioned by the stationary flowhead die on the other end. In shuttle machinery and reciprocating screw machinery multiple parisons are extruded and are free hanging. Because there is always some variation in the parison length on these machines, bottle weight and tolerance consistencies are not as tight as on rotary wheel machinery.
Other advantages of wheel equipment include:
Disadvantages:
Applications.
The growth of wheel machinery in the United States was spurred by the conversion of motor oil containers from paperboard cans to plastic bottles, and the conversion of laundry detergent from powder to liquid form. Additional high volume applications have included single-serve juices and drinkable yogurt, condiments, and household cleaning supplies.


Roll-to-roll processing

In the field of electronic devices, roll-to-roll processing, also known as web processing, reel-to-reel processing or R2R, is the process of creating electronic devices on a roll of flexible plastic, metal foil, or flexible glass. In other fields predating this use, it can refer to any process of applying coating, printing, or performing other processes starting with a roll of a flexible material and re-reeling after the process to create an output roll. These processes, and others such as sheeting, can be grouped together under the general term converting. When the rolls of material have been coated, laminated or printed they can be subsequently slit to their finished size on a slitter rewinder.
In electronic devices.
Large circuits made with thin-film transistors and other devices can be patterned onto these large substrates, which can be up to a few meters wide and long. Some of the devices can be patterned directly, much like an inkjet printer deposits ink. For most semiconductors, however, the devices must be patterned using photolithography techniques.
Roll-to-roll processing of large-area electronic devices reduces manufacturing cost. Most notable would be solar cells, which are still prohibitively expensive for most markets due to the high cost per unit area of traditional bulk (mono- or polycrystalline) silicon manufacturing. Other applications could arise which take advantage of the flexible nature of the substrates, such as electronics embedded into clothing, large-area flexible displays, and roll-up portable displays.
Thin-film cells.
A crucial issue for a roll-to-roll thin-film cell production system is the deposition rate of the microcrystalline layer, and this can be tackled using four approaches:
In electrochemical devices.
The roll-to-roll processing has been used in the manufacture of electrochemical devices such as batteries, supercapacitors, fuel cells, and water electrolyzers. Here, the roll-to-roll processing is utilized for electrode manufacturing and is the key to reducing manufacturing cost through stable production of electrodes on various film substrates such as metal foils, membranes, diffusion media, and separators.


Strategic partnership

A strategic partnership (also see strategic alliance) is a relationship between two commercial enterprises, usually formalized by one or more business contracts. A strategic partnership will usually fall short of a legal partnership entity, agency, or corporate affiliate relationship. Strategic partnerships can take on various forms from shake hand agreements, contractual cooperation's all the way to equity alliances, either the formation of a joint venture or cross-holdings in each other.
Typically, two companies form a strategic partnership when each possesses one or more business assets or have expertise that will help the other by enhancing their businesses. This can also mean, that one firm is helping the other firm to expand their market to other marketplaces, by helping with some expertise. According to Cohen and Levinthal a considerable in-house expertise which complements the technology activities of its partner is a necessary condition for a successful exploitation of knowledge and technological capabilities outside their boundaries. Strategic partnerships can develop in outsourcing relationships where the parties desire to achieve long-term “win-win” benefits and innovation based on mutually desired outcomes.
No matter if a business contract was signed, between the two parties, or not, a trust-based relationship between the partners is indispensable.
One common strategic partnership involves one company providing engineering, manufacturing or product development services, partnering with a smaller, entrepreneurial firm or inventor to create a specialized new product. Typically, the larger firm supplies capital, and the necessary product development, marketing, manufacturing, and distribution capabilities, while the smaller firm supplies specialized technical or creative expertise.
Another common strategic partnership involves a manufacturer/supplier partnering with a distributor or wholesale consumer. Rather than approach the transactions between the companies as a simple link in the product or service supply chain, the two companies form a closer relationship where they mutually participate in advertising, marketing, branding, product development, and other business functions. As examples, an automotive manufacturer may form strategic partnerships with its parts suppliers, or a music distributor with record labels.
The activities of a strategic partnership can also include a shared research & development department between the partners. This requires a higher level of knowledge sharing as well as a higher level of sharing the technological capabilities. But by doing so, the costs and risks of innovation can be spread between the partners.
Strategic partnerships also have emerged to solve many company business problems. The book "Vested: How P&G, McDonald’s and Microsoft are Redefining Winning in Business Relationships" profiles strategic partnerships in large scale business process outsourcing relationships, public-private infrastructure projects, facilities management and supply chain relationships. Contemporary strategic sourcing and procurement processes enable organizations to use performance-based or vested sourcing business models for establishing strategic supplier relationships.
There can be many advantages to creating strategic partnerships. As Robert M. Grant states in his book "Contemporary Strategy Analysis", "For complete strategies, as opposed to individual projects, creating option value means positioning the firm such that a wide array of opportunities become available". Firms taking advantage of strategic partnerships can utilize other company's strengths to make both firms stronger in the long run.
Strategic partnerships raise questions concerning co-inventorship and other intellectual property ownership, technology transfer, exclusivity, competition, hiring away of employees, rights to business opportunities created in the course of the partnership, splitting of profits and expenses, duration and termination of the relationship, and many other business issues. Another risk of strategic partnerships, especially between manufacturer and key supplier, is the potential forward integration by the key supplier. Also different developments or development plans can lead to a broken strategic partnership. The relationships are often complex as a result, and can be subject to extensive negotiation. Strategic partnerships are also prone to conflict. The University of Tennessee has done significant research into strategic partnerships, especially in the area of strategic outsourcing relationships.


Converters (industry)

Converting companies are companies that specialize in modifying or combining raw materials such as polyesters, adhesives, silicone, adhesive tapes, foams, plastics, felts, rubbers, liners and metals, as well as other materials, to create new products.
Materials such as paper, plastic film, foil and cloth often are produced in long, continuous sheets that are rolled up for more convenient handling and transportation. These rolls of material vary significantly in size and weight — ranging from wide and weighing as much as several tons. The converting industry takes these continuous rolls of thin, flat materials — known as webs — threads them through processing machines (such as printing presses, laminating, coating and slitting machines) and converts or changes the web of material into an intermediate form or final product. For example, a converter’s equipment might take a web of plastic film, cut it into lengths, and fuse their edges, thus converting it into plastic bags. This activity is known as web processing.
Processes.
Typical converting processes include coating, laminating and printing. Coating technologies can include hot melt coating, gravure coating, curtain coating and slot-die coating. The most common printing techniques are flexo printing and rotogravure (gravure) printing. Both print processes are suited to high speed roll-to-roll processing.
Many converting companies will process large diameter, wide rolls of material as this increases the converting efficiency by minimising changes. On completion of the converting process the rolls may be cut into smaller rolls on a slitting machine or a sheeter. These rolls or sheets are then a convenient size for handling on packaging and other machines. Further processes such as collation may occur after sheeting.
Depending on the specially of the converter, many other processes might be involved. These might include: shearing, die-cutting, laser cutting, heat sealing, laser converting, perforating, Ultrasonic welding, Surface finishing, etc.
Web alignment.
When converting from rolls of material, web alignment is an important part of a converting operation as a moving web of material has a tendency to track off course and wander out of alignment during the converting processes. To avoid these problems, engineers have developed a variety of automatic web-guiding systems that assure production accuracy and reduce waste. Web-guiding systems typically are positioned just before a critical stage on a converting machine (for example, just before a print station on a printing press).
Each type of web guiding system uses a sensor to monitor the web position for lateral tracking, and each has an actuator to shift the running web mechanically back on course whenever the sensor detects movement away from the set path. Actuators may be pneumatic or hydraulic cylinders, or some kind of electromechanical device. Because the web may be fragile — particularly at its edge — non-contact sensors are used. These sensors may be pneumatic, photoelectric, ultrasonic, or infrared. The system’s controls must put the output signals from the sensors in to a form that can drive the actuator. Many controls today are electronic, typically using an amplifier to convert signals from the sensor, then commanding a special servo motor incorporating a lead or ball screw for guiding actuation. The latest web guiding systems have touch screen controls to simplify the setup procedure. Some web guiding systems have been designed specifically for the converting industry.
Services.
Many converters specialize in
Newer technology.
Some converting companies now incorporate electronics in their finished products. For example, converters producing RFID stock labels must incorporate RFID chips and antenna inlays. The electronic components make up the RFID tag. The tag stores the information about the items that have been tagged. These converters therefore sometimes incorporate volume electronics manufacturing practices including controlling static electricity, electronic manufacturing test and similar processes. Solving some of the issues of inclusion of materials sensitive to external influences has led to more tech companies embracing roll-based manufacturing processes, with particular success in the lithium ion and solar cell manufacturing sectors.
Paper converting.
Paper converting can refer to manufacturing processes involving paper as the raw material. This raw material, similar to other converting industries, can be in a roll or sheet form. Paper converting is required for the manufacture of nearly all paper based products, such as magazines, books, newspapers, labels, bags, and general purpose paper products.
The process of processing pre-cut cartons or "blanks" and folding them into the appropriate shape to become finished packaging containers is known as tray forming or carton erecting. This is a specific example of a type of converting. These machines can create, for example, nacho trays, chinese noodle soup boxes, pizza boxes, french fry trays, hamburger clamshells, etc.


Hybrid silicon laser

A hybrid silicon laser is a semiconductor laser fabricated from both silicon and group III-V semiconductor materials. The hybrid silicon laser was developed to address the lack of a silicon laser to enable fabrication of low-cost, mass-producible silicon optical devices. The hybrid approach takes advantage of the light-emitting properties of III-V semiconductor materials combined with the process maturity of silicon to fabricate electrically driven lasers on a silicon wafer that can be integrated with other silicon photonic devices.
Physics.
A hybrid silicon laser is an optical source that is fabricated from both silicon and group III-V semiconductor materials (e.g. Indium(III) phosphide, Gallium(III) arsenide). It comprises a silicon waveguide fused to an active, light-emitting, III-V epitaxial semiconductor wafer. The III-V epitaxial wafer is designed with different layers such that the active layer can emit light when it is excited either by shining light, e.g. a laser onto it; or by passing electricity through it. The emitted light from the active layer couples into the silicon waveguide due to their close proximity (cavity.
Fabricate.
The silicon laser is fabricated by a technique called plasma assisted wafer bonding. Silicon waveguides are first fabricated on a silicon on insulator (SOI) wafer. This SOI wafer and the un-patterned III-V wafer are then exposed to an oxygen plasma before being pressed together at a low (for semiconductor manufacturing) temperature of 300C for 12 hours. This process fuses the two wafers together. The III-V wafer is then etched into mesas to expose electrical layers in the epitaxial structure. Metal contacts are fabricated on these contact layers allowing electric current to flow to the active region.
Silicon manufacturing and fabrication is widely used in the electronic industry to mass-produce low-cost electronic devices. Silicon photonics uses these same electronic manufacturing technologies to make low-cost integrated optical devices. One issue with using silicon for an optical device is that silicon is a poor light emitter and cannot be used to make an electrically pumped laser. This means that lasers have first to be fabricated on a separate III-V semiconductor wafer before being individually aligned to each silicon device, in a process that is both costly and time-consuming, limiting the total number of lasers that can be used on a silicon photonic circuit. By using this wafer bonding technique many hybrid silicon lasers can be fabricated simultaneously on a silicon wafer, all aligned to the silicon photonic devices.
Uses.
Potential uses cited in the references below include fabricating many, possibly hundreds of hybrid silicon lasers on a die and using silicon photonics to combine them together to form high bandwidth optical links for personal computers, servers or back planes. These lasers are now fabricated on 300 mm silicon wafers in CMOS foundries in volumes of over one million per year.
The low loss of silicon waveguides means these lasers can have very narrow linewidths (LIDARs, optical gyroscopes, and other applications. These lasers can be used to pump nonlinear devices to make optical synthesizers with a stability of 1 part in 1017.


Contingency allowance

The contingency allowance is the time allocated during planning for unscheduled events. Technical and personal disruptions result in changes in the indirect production costs. The contingency allowance is calculated in special contingency time studies, the results of which yield rates for indirect production costs. The time is usually added to the pure operations time to form a standard time in manufacturing.
The concept was developed by Charles Bedaux.


Quad in-line package

In microelectronics, a quad in-line package (QIP or QIL), is an electronic component package with a rectangular housing and four parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. Rockwell used a QIP with 42 leads formed into staggered rows for their PPS-4 microprocessor family introduced in 1973, and other microprocessors and microcontrollers, some with higher lead counts, through the early 1990s.
The QIP has the same dimensions as a Dual in-line package (DIP), but the leads on each side are bent into an alternating zigzag configuration so as to fit four lines of solder pads (instead of two with a DIP but similar to Zig-zag in-line package). The QIP design increased the spacing between solder pads without increasing package size, for two reasons:
Some QIP packaged ICs had added heatsinking tabs, such as the HA1306W.
Intel and 3M developed the ceramic leadless quad in-line package (QUIP), introduced in 1979, to boost microprocessor density and economy. The ceramic leadless QUIP is not designed for surface-mount use, and requires a socket. It was used by Intel for the iAPX 432 microprocessor chip set, and by Zilog for the Z8-02 external-ROM prototyping version of the Z8 microcontroller.


List of number-one digital tracks of 2007 (Australia)

The ARIA Digital Track Chart ranks the best-performing digital tracks of Australia. It is published by Australian Recording Industry Association (ARIA), an organisation who collects music data for the weekly ARIA Charts.
To be eligible to appear on the chart, the recording must be a single not an EP and only paid downloads counted from downloadable outlets.


Reverse costing

Reverse costing describes the process of disassembling (reverse engineering) a device to identify manufacturing technology and calculate its manufacturing costs through a cost analysis of its parts and the effort required to assemble them.


Plastic welding

Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat (except solvent welding). Welding of thermoplastics is accomplished in three sequential stages, namely surface preparation, application of heat and pressure, and cooling. Numerous welding methods have been developed for the joining of semi-finished plastic materials. Based on the mechanism of heat generation at the welding interface, welding methods for thermoplastics can be classified as external and internal heating methods, as shown in Fig 1.
Production of a good quality weld does not only depend on the welding methods, but also weldability of base materials. Therefore, the evaluation of weldability is of higher importance than the welding operation (see Rheological weldability) for plastics.
Welding techniques.
A number of techniques are used for welding of semi-finished plastic products as given below:
Hot gas welding.
Hot gas welding, also known as "hot air welding", is a plastic welding technique using heat. A specially designed heat gun, called a "hot air welder", produces a jet of hot air that softens both the parts to be joined and a plastic filler rod, all of which must be of the same or a very similar plastic. (Welding PVC to acrylic is an exception to this rule.)
Hot air/gas welding is a common fabrication technique for manufacturing smaller items such as chemical tanks, water tanks, heat exchangers, and plumbing fittings.
In the case of webs and films a filler rod may not be used. Two sheets of plastic are heated via a hot gas (or a heating element) and then rolled together. This is a quick welding process and can be performed continuously.
Welding rod.
A plastic welding rod, also known as a "thermoplastic welding rod", is a rod with circular or triangular cross-section used to bind two pieces of plastic together. They are available in a wide range of colors to match the base material's color. Spooled plastic welding rod is known as "spline".
An important aspect of plastic welding rod design and manufacture is the porosity of the material. A high porosity will lead to air bubbles (known as "voids") in the rods, which decrease the quality of the welding. The highest quality of plastic welding rods are therefore those with zero porosity, which are called "voidless".
Heat sealing.
Heat sealing is the process of sealing one thermoplastic to another similar thermoplastic using heat and pressure. The direct contact method of heat sealing utilizes a constantly heated die or sealing bar to apply heat to a specific contact area or path to seal or weld the thermoplastics together. Heat sealing is used for many applications, including heat seal connectors, thermally activated adhesives and film or foil sealing. Common applications for the heat sealing process: Heat seal connectors are used to join LCDs to PCBs in many consumer electronics, as well as in medical and telecommunication devices. Heat sealing of products with thermal adhesives is used to hold clear display screens onto consumer electronic products and for other sealed thermo-plastic assemblies or devices where heat staking or ultrasonic welding is not an option due to part design requirements or other assembly considerations. Heat sealing also is used in the manufacturing of bloodtest film and filter media for the blood, virus and many other test strip devices used in the medical field today. Laminate foils and films often are heat sealed over the top of thermoplastic medical trays, Microtiter (microwell) plates, bottles and containers to seal and/or prevent contamination for medical test devices, sample collection trays and containers used for food products. Medical and the Food Industries manufacturing Bag or flexible containers use heat sealing for either perimeter welding of the plastic material of the bags and/or for sealing ports and tubes into the bags. A variety of heat sealers are available to join thermoplastic materials such as plastic films: Hot bar sealer, Impulse sealer, etc.
Freehand welding.
With freehand welding, the jet of hot air (or inert gas) from the welder is placed on the weld area and the tip of the weld rod at the same time. As the rod softens, it is pushed into the joint and fuses to the parts. This process is slower than most others, but it can be used in almost any situation.
Speed tip welding.
With speed welding, the plastic welder, similar to a soldering iron in appearance and wattage, is fitted with a feed tube for the plastic weld rod. The speed tip heats the rod and the substrate, while at the same time it presses the molten weld rod into position. A bead of softened plastic is laid into the joint, and the parts and weld rod fuse. With some types of plastic such as polypropylene, the melted welding rod must be "mixed" with the semi-melted base material being fabricated or repaired. These welding techniques have been improved over time and have been utilized for over 50 years by professional plastic fabricators and repairers internationally. Speed tip welding method is a much faster welding technique and with practice can be used in tight corners.
A version of the speed tip "gun" is essentially a soldering iron with a broad, flat tip that can be used to melt the weld joint and filler material to create a bond.
Extrusion welding.
Extrusion welding allows the application of bigger welds in a single weld pass. It is the preferred technique for joining material over 6 mm thick. Welding rod is drawn into a miniature hand held plastic extruder, plasticized, and forced out of the extruder against the parts being joined, which are softened with a jet of hot air to allow bonding to take place.
Contact welding.
This is the same as spot welding except that heat is supplied with thermal conduction of the pincher tips instead of electrical conduction. Two plastic parts are brought together where heated tips pinch them, melting and joining the parts in the process.
Hot plate welding.
Related to contact welding, this technique is used to weld larger parts, or parts that have a complex weld joint geometry. The two parts to be welded are placed in the tooling attached to the two opposing platens of a press. A hot plate, with a shape that matches the weld joint geometry of the parts to be welded, is moved in position between the two parts. The two opposing platens move the parts into contact with the hot plate until the heat softens the interfaces to the melting point of the plastic. When this condition is achieved the hot plate is removed, and the parts are pressed together and held until the weld joint cools and re-solidifies to create a permanent bond.
Hot-plate welding equipment is typically controlled pneumatically, hydraulically, or electrically with servo motors.
This process is used to weld automotive under hood components, automotive interior trim components, medical filtration devices, consumer appliance components, and other car interior components.
Non-contact/IR welding.
Similar to hot plate welding, non-contact welding uses an infrared heat source to melt the weld interface rather than a hot plate. This method avoids the potential for material sticking to the hot plate, but is more expensive and more difficult to achieve consistent welds, particularly on geometrically complex parts.
High frequency welding.
High Frequency welding, also known as Dielectric Sealing or Radio Frequency (R.F.) Heat Sealing is a very mature technology that has been around since the 1940s. High frequency electromagnetic waves in the range of radio frequencies can heat certain polymers up to soften the plastics for joining. Heated plastics under pressure weld together. Heat is generated within the polymer by the rapid reorientation of some chemical dipoles of the polymer, which means that the heating can be localized, and the process can be continuous.
Only certain polymers which contain dipoles can be heated by RF waves, in particular polymers with high loss power. Among these, PVC, polyamides (PA) and acetates are commonly welded with this technology. In practice, two pieces of material are placed on a table press that applies pressure to both surface areas. Dies are used to direct the welding process. When the press comes together, high frequency waves (usually 27.120 MHz) are passed through the small area between the die and the table where the weld takes place. This high frequency (radio frequency) heats the plastic which welds under pressure, taking the shape of the die.
RF welding is fast and relatively easy to perform, produces a limited degradation of the polymer even welding thick layers, does not create fumes, requires a moderate amount of energy and can produce water-, air-, and bacteria-proof welds. Welding parameters are welding power, (heating and cooling) time and pressure, while temperature is generally not controlled directly. Auxiliary materials can also be used to solve some welding problems. This type of welding is used to connect polymer films used in a variety of industries where a strong consistent leak-proof seal is required. In the fabrics industry, RF is most often used to weld PVC and polyurethane (PU) coated fabrics. Other materials commonly welded using this technology are nylon, PET, PEVA, EVA and some ABS plastics. Exercise caution when welding urethane as it has been known to give off cyanide gasses when melting.
Induction welding.
When an electrical insulator, like a plastic, is embedded with a material having high electrical conductivity, like metals or carbon fibers, induction welding can be performed. The welding apparatus contains an induction coil that is energised with a radio-frequency electric current. This generates an electromagnetic field that acts on either an electrically conductive or a ferromagnetic workpiece. In an electrically conductive workpiece, the main heating effect is resistive heating, which is due to induced currents called eddy currents. Induction welding of carbon fiber reinforced thermoplastic materials is a technology commonly used in for instance the aerospace industry.
In a ferromagnetic workpiece, plastics can be induction-welded by formulating them with metallic or ferromagnetic compounds, called susceptors. These susceptors absorb electromagnetic energy from an induction coil, become hot, and lose their heat energy to the surrounding material by thermal conduction.
Injection welding.
Injection welding is similar/identical to extrusion welding, except, using certain tips on the handheld welder, one can insert the tip into plastic defect holes of various sizes and patch them from the inside out. The advantage is that no access is needed to the rear of the defect hole. The alternative is a patch, except that the patch can not be sanded flush with the original surrounding plastic to the same thickness. PE and PP are most suitable for this type of process. The Drader injectiweld is an example of such tool.
Ultrasonic welding.
In ultrasonic welding, high frequency (15 kHz to 40 kHz) low amplitude vibration is used to create heat by way of friction between the materials to be joined. The interface of the two parts is specially designed to concentrate the energy for the maximum weld strength. Ultrasonic can be used on almost all plastic material. It is the fastest heat sealing technology available.
Friction welding.
In friction welding, the two parts to be assembled are rubbed together at a lower frequency (typically 100–300 Hz) and higher amplitude (typically ) than ultrasonic welding. The friction caused by the motion combined with the clamping pressure between the two parts creates the heat which begins to melt the contact areas between the two parts. At this point, the plasticized materials begin to form layers that intertwine with one another, which therefore results in a strong weld. At the completion of the vibration motion, the parts remain held together until the weld joint cools and the melted plastic re-solidifies. The friction movement can be linear or orbital, and the joint design of the two parts has to allow this movement.
Spin welding.
Spin welding is a particular form of frictional welding. With this process, one component with a round weld joint is held stationary, while a mating component is rotated at high speed and pressed against the stationary component. The rotational friction between the two components generates heat. Once the joining surfaces reach a semi-molten state, the spinning component is stopped abruptly. Force on the two components is maintained until the weld joint cools and re-solidifies. This is a common way of producing low- and medium-duty plastic wheels, e.g., for toys, shopping carts, recycling bins, etc. This process is also used to weld various port openings into automotive under hood components.
Laser welding.
This technique requires one part to be transmissive to a laser beam and either the other part absorptive or a coating at the interface to be absorptive to the beam. The two parts are put under pressure while the laser beam moves along the joining line. The beam passes through the first part and is absorbed by the other one or the coating to generate enough heat to soften the interface creating a permanent weld.
Semiconductor diode lasers are typically used in plastic welding. Wavelengths in the range of 808 nm to 980 nm can be used to join various plastic material combinations. Power levels from less than 1W to 100W are needed depending on the materials, thickness and desired process speed.
Diode laser systems have the following advantages in joining of plastic materials:
Requirements for high strength joints include adequate transmission through upper layer, absorption by lower layer, materials compatibility (wetting), good joint design (clamping pressure, joint area), and lower power density.
Some materials that can be joined include polypropylene, polycarbonate, acrylic, nylon, and ABS.
Specific applications include sealing, welding, or joining of: catheter bags, medical containers, automobile remote control keys, heart pacemaker casings, syringe tamper evident joints, headlight or tail-light assemblies, pump housings, and cellular phone parts.
Transparent laser plastic welding.
New fiber laser technology allows for the output of longer laser wavelengths, with the best results typically around 2,000 nm, significantly longer than the average 808 nm to 1064 nm diode laser used for traditional laser plastic welding. Because these longer wavelengths are more readily absorbed by thermoplastics than the infrared radiation of traditional plastic welding, it is possible to weld two clear polymers without any colorants or absorbing additives. Common applications will mostly fall in the medical industry for devices like catheters and microfluidic devices. The heavy use of transparent plastics, especially flexible polymers like TPU, TPE and PVC, in the medical device industry makes transparent laser welding a natural fit. Also, the process requires no laser absorbing additives or colorants making testing and meeting biocompatibility requirements significantly easier.
Solvent welding.
In solvent welding, a solvent is applied which can temporarily dissolve the polymer at room temperature. When this occurs, the polymer chains are free to move in the liquid and can mingle with other similarly dissolved chains in the other component. Given sufficient time, the solvent will permeate through the polymer and out into the environment, so that the chains lose their mobility. This leaves a solid mass of entangled polymer chains which constitutes a solvent weld.
This technique is commonly used for connecting PVC and ABS pipe, as in household plumbing. The "gluing" together of plastic (polycarbonate, polystyrene or ABS) models is also a solvent welding process.
Dichloromethane (methylene chloride) can solvent weld polycarbonate and polymethylmethacrylate. It is a primary ingredient in some solvent cements. ABS plastic is typically welded with Acetone based solvents which are often sold as paint thinners or in smaller containers as nail polish remover.
Solvent welding is a common method in plastics fabrication and used by manufacturers of in-store displays, brochure holders, presentation cases and dust covers. Another popular use of solvents in the hobby segment is model building from injection molded kits for scale models of aircraft, ships and cars which predominantly use Polystyrene plastic.
Testing of plastic welds.
In order to test plastic welds, there are several requirements for both the inspector as well as the test method. Furthermore, there are two different types of testing weld quality. These two types are destructive and non-destructive testing. Destructive testing serves to qualify and quantify the weld joint whereas nondestructive testing serves to identify anomalies, discontinuities, cracks, and/or crevices. As the names of these two tests implies, destructive testing will destroy the part that is being tested while nondestructive testing enables the test piece to be used afterwards. There are several methods available in each of these types. This section outlines some requirements of testing plastic welds as well as the different types of destructive and non-destructive methods that are applicable to plastic welding and go over some of the advantages and disadvantages.
Testing requirements.
Some standards like the American Welding Society (AWS) require the individuals who are conducting the inspection or test to have a certain level of qualification. For example, AWS G1.6 is the Specification for the Qualification of Plastic Welding Inspectors for Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds. This particular standard dictates that in order to inspect the plastic welds, the inspector needs one of 3 different qualification levels. These levels are the Associate Plastics Welding Inspector (APWI), Plastics Welding Inspector (PWI), and Senior Plastics Welding Inspector (SPWI). Each of these levels have different responsibilities. For example, the APWI has to have direct supervision of a PWI or SPWI in order to conduct the inspection or prepare a report. These three different levels of certification also have different capability requirements, education requirements, and examination requirements. Additionally, they must be able to maintain that qualification every 3 years.
Destructive testing.
Bend testing.
The bend test uses a ram to bend the test coupon to a desired degree. This test setup is shown in Figure 2.
A list of the minimum bend angles and ram displacements for different plastic materials can be found in the DVS Standards, DVS2203-1 and DVS2203-5. Some of the ram speeds, bend angle, and displacement information from DVS2203-1 are shown in Table 1 and Table 2.
Some of the main advantages of the bend test are it provides qualitative data for tensile, compressive, and shear strain. These results typically lead to a higher confidence level in the quality of the weld joint and process. In contrast, some of the disadvantages are it requires multiple test pieces. It is typically recommended to use a minimum of 6 different test samples. Another disadvantage is that it does not provide specific values for evaluating the joint design. Moreover, large amounts of effort may need to go into preparing the part for testing. This could cause an increase in cost and schedule depending on the complexity of the part. Lastly, like all destructive tests, the part and/or weld seam is destroyed and cannot be used.
Tensile testing.
When conducting the tensile test, a test piece is pulled until it breaks. This test is quantitative and will provide the ultimate tensile strength, strain, as well as the energy to failure if it has extensometers attached to the sample. Additionally, the results from a tensile test cannot be transferable to that of a creep test. The rate at which the specimen is pulled depends on the material. Additionally, the shape of the specimen is also critical. DVS2203-5 and AWS G1.6 are great sources for providing these details. Examples of the shapes are shown in Figure 3 through Figure 5. Additionally, the testing speed per material is shown in Table 3.
One advantage of the tensile test is that it provides quantitative data of the weld for both weld seam and the base material. Additionally, the tensile test is easy to conduct. A major disadvantage of this testing is the amount of preparation required to conduct the test. Another disadvantage is that it does not provide the long-term weld performance. Additionally, since this is also a type of destructive test, the part is destroyed in order to collect this data.
Impact Testing.
Also known as the Tensile Impact Test, the Impact Test uses a specimen that is clamped into a pendulum. The test specimen looks like the one shown in Figure 4. The pendulum swings down and strikes the specimen against an anvil breaking the specimen. This test enables the impact energy to be determined for the weld seam and base material. Additionally, the permanent fracture elongation can be calculated by measuring the post-test specimen length. The main advantage of this test is that quantitative data is obtained. Another advantage is that it is easy to set up. The disadvantages are that it too can have a great deal of preparation in order to conduct this test. Also, like the tensile test, there is not a long term weld performance determined, and the part is destroyed.
Creep test.
There are two types of creep tests, the Tensile Creep Test and the Creep Rupture Test. Both creep tests look at the long-term weld performance of the test specimen. These tests are typically conducted in a medium at a constant temperature and constant stress. This test requires a minimum of 6 specimens in order to obtain enough data to conduct a statistical analysis. This test is advantageous in that it provides quantitative data on the long-term weld performance; however, it has its disadvantages as well. There is a lot effort that needs to go into preparing the samples and recording where exactly the specimen came from and the removal method used. This is critical because how the specimen is removed from the host part can greatly influence the test results. Also, there has to be strict control of the test environment. A deviation in the medium's temperature can cause the creep rupture time to vary drastically. In some cases, a temperature change of 1 degree Celsius affected the creep rupture time by 13%. Lastly, this test is again a destructive test, so the host part will be destroyed by conducting this type of test.
Non-destructive testing.
Visual examination.
Visual inspection, just like the name implies, is a visual investigation of the weldment. The inspector is typically looking for visual indications such as discolorations, weld defects, discontinuities, porosity, notches, scratches, etc. Typically visual inspection is broken down into different categories or groups for the qualifying inspection criteria. These groupings may vary among standards and each group has a certain level of imperfections that they consider acceptable. There are 5 tables and a chart found in DVS Standard DVS2202-1 that show different types of defects found by visual examination and their permissible acceptance criteria.
Visual inspection is very advantageous in the fact that it is quick, easy, inexpensive, and requires very simple tools and gauges in order to conduct. Because it is so quick, it is typically required to have a weld pass visual inspection prior to being able to have any additional nondestructive test conducted to the specimen. In contrast, the inspection needs to be completed by someone who has a lot of experience and skill. Additionally, this type of test will not give any data into the quality of the weld seam. Because of the low cost, if a part is suspected to have issues, follow on testing can be conducted without much initial investment.
X-ray testing.
X-ray testing of plastics is similar to that of metal weldments, but uses much lower radiation intensity due to the plastics having a lower density than metals. The x-ray testing is used to find imperfections that are below the surface. These imperfections include porosity, solid inclusions, voids, crazes, etc. The x-ray transmits radiation through the tested object onto a film or camera. This film or camera will produce an image. The varying densities of the object will show up as different shades in the image thus showing where the defects are located. One of the advantages of X-ray is that it provides a way to quickly show the flaws both on the surface and inside the weld joint. Additionally, the X-ray can be used on a wide range of materials. They can be used to create a record for the future. One of the disadvantages of X-ray is that it is costly and labor-intensive. Another is that it cannot be used in the evaluation of the weld seam quality or optimize the process parameters. Additionally, if the discontinuity is not aligned properly with the radiation beam, it can be difficult to detect. A fourth disadvantage is that access to both sides of the component being measured is required. Lastly, it presents a health risk due to the radiation that is transmitted during the X-ray process.
Ultrasonic testing.
Ultrasonic testing utilizes high frequency sound waves passing through the weld. The waves are reflected or refracted if they hit an indication. The reflected or refracted wave will have a different amount of time it requires to travel from the transmitter to the receiver than it will if an indication was not present. This change in time is how the flaws are detected. The first advantage that ultrasonic testing provides is that it allows for a relatively quick detection of the flaws inside of the weld joint. This test method also can detect flaws deep inside the part. Additionally, it can be conducted with access from only one side of the part. In contrast, there are several disadvantages of using ultrasonic testing. The first is that it cannot be used to optimize the process parameters or evaluate the seam quality of the weld. Secondly, it is costly and labor-intensive. It also requires experienced technicians to conduct the test. Lastly, there are material limitations with plastics due to transmission limitations of the ultrasonic waves through some of the plastics. The image in Figure 6 shows an example of ultrasonic testing.
High voltage leak testing.
High voltage testing is also known as spark testing. This type of testing utilizes electrically conductive medium to coat the weld. After the weld is coated, the weld is exposed to a high voltage probe. This test shows an indication of a leak in the weld when an arc is observed through the weld. This type of testing is advantageous in the fact that it allows for quick detection of the flaws inside the weld joint and that you only have to have access to one side of the weld. One disadvantage with this type of testing is that there is not a way to evaluate the weld seam quality. Additionally, the weld has to be coated with conductive material.
Leak-tightness testing.
Leak-Tightness Testing or Leak Testing utilizes either liquid or gas to pressurize a part. This type of testing is typically conducted on tubes, containers, and vessels. Another way to leak-test one of these structures is to apply a vacuum to it. One of the advantages is that it is a quick simple way for the weld flaw to be detected. Additionally, it can be used on multiple materials and part shapes. On the other hand, it has a few disadvantages. Firstly, there is not a way to evaluate the weld seam quality. Secondly, it has an explosion hazard associated with it if over pressurization occurs during testing. Last, it is limited to tubular structures.,


Direct chill casting

Direct Chill casting is a method for the fabrication of cylindrical or rectangular solid ingots from non-ferrous metals, especially Aluminum, Copper, Magnesium and their alloys. The original ingots are usually further processed by other methods (rolling, forging, etc.). More than half of global aluminum production uses the Direct Chill casting process.
Direct Chill casting operates by pouring liquid metal continuously into a short mold (7.5–15 cm deep) that is open at the bottom. Only an outer layer of metal solidifies within the water-cooled mold. After leaving the closed mold at its bottom (e.g. with 5–15 cm/min), water is directly sprayed on the new ingot, continuing the solidification until complete. Only about 20% of the heat of the molten metal is removed through the mold wall, the secondary cooling (Direct Chill) contributing the majority of cooling. Typically the process is started with a starter-dummy block at the bottom of the mold, and runs until the maximum length possible in the machine is reached (up to 10 m).
The casting method reduces the internal stress in the cooled material by allowing contractions on all sides, as opposed to only on the top of the ingot in a traditional trough mold.