Machine tool builder

A machine tool builder is a corporation or person that builds machine tools, usually for sale to manufacturers, who use them to manufacture products. A machine tool builder runs a machine factory, which is part of the machine industry.
The machine tools often make interchangeable parts, which are assembled into subassemblies or finished assemblies, ending up sold to consumers, either directly or through other businesses at intermediate links of a value-adding chain. Alternatively, the machine tools may help make molds or dies, which then make the parts for the assemblies.
Overview.
The term "machine tool builder" implies a company that builds machine tools for sale to other companies, who then use them to manufacture subsequent products. Macroeconomically, machine tools are only means to ends (with the ends being the manufactured products); they are not the ends themselves. Thus it is in the nature of machine tools that there is a spectrum of relationships between their builders, their users, and the end users of the products that they make.
There is always natural potential for the machine tool users to be the same people as the builders, or to be different people who occupy an intermediate position in the value stream. Markets often have some proclivity for circumventing such a position, although the proclivity is often not absolute. Every variant on the spectrum of relationships has found some instances of empirical embodiment; and over the centuries, trends can be seen for which variants predominated in each era, as described below.
Machine tool builders tend not to be in the business of using the machine tools to manufacture the subsequent products (although exceptions,
including chaebol and keiretsu, do exist); and product manufacturers tend not to be in the business of building machine tools. In fact, many machine tool builders are not even in the business of building the control system (typically CNC) that animates the machine; and makers of controls tend not to be in the machine building business (or to inhabit only specialized niches within it).
For example, FANUC and Siemens make controls that are sold to many machine tool builders. Each segment tends to find that crossing into other segments involves becoming a conglomerate of dissimilar businesses, which is an execution headache that they don't need as long as focusing on a narrower field is often more profitable in net effect anyway. This trend can be compared to the trend in which companies choose not to compete against their own distributors. Thus a software company may have an online store, but that store does not undercut the distributors' stores on price.
History.
The machine tool industry began gradually in the early nineteenth century with individual toolmakers who innovated in machine tool design and building. The ones that history remembers best include Henry Maudslay, Joseph Whitworth, Joseph Clement, James Nasmyth, Matthew Murray, Elisha K. Root, Frederick W. Howe, Stephen Fitch, J.D. Alvord, Frederick W. Howe, Richard S. Lawrence, Henry D. Stone, Christopher M. Spencer, Amos Whitney, and Francis A. Pratt.
The industry then grew into the earliest corporate builders such as Brown & Sharpe, the Warner & Swasey Company, and the original Pratt & Whitney company. In all of these cases, there were product manufacturers who started building machine tools to suit their own inhouse needs, and eventually found that machine tools had become product lines in their own right. (In cases such as B&S and P&W, they became the main or sole product lines.)
In contrast, Colt and Ford are good examples of product manufacturers that made significant advances in machine tool building while serving their own inhouse needs, but never became "machine tool builders" in the sense of having machine tools become the products that they sold. National-Acme was an example of a manufacturer and a machine tool builder merging into one company and selling both the machines and the products that they made (screw machines and fasteners). Hyundai and Mitsubishi are chaebol and keiretsu conglomerates (respectively), and their interests cover from ore mine to end user (in actuality if not always nominally).
Until the 1970s, machine tool builder corporations could generally be said to have nationality, and thus it made sense to talk about an American machine tool builder, a German one, or a Japanese one. Since the 1970s, the industry has globalized to the point that assigning nationality to the corporations becomes progressively more meaningless as one travels down the timeline leading up to the present day; currently, most machine tool builders are (or are subsidiaries of) multinational corporations or conglomerates. With these companies it is enough to say "multinational corporation based in country X", "multinational corporation founded in country X", etc. Subcategories such as "American machine tool builders" or "Japanese machine tool builders" would be senseless because, for example, companies like Hardinge and Yamazaki Mazak today have significant operations in many countries.
Trade associations.
Machine tool builders have long had trade associations, which have helped with such tasks as establishing industry standards, lobbying (of legislatures and, more often, import-and-export-regulating agencies), and training programs. For example, the National Machine Tool Builders' Association (NMTBA) was the trade association of U.S. machine tool builders for many decades, and it helped establish standards such as the NMTB machine taper series (which made toolholders interchangeable between the different brands of machine on a typical machine shop floor). It has since been merged into the Association for Manufacturing Technology (AMT). Other examples have included CECIMO (European Machine Tool Industry Association), the UK's ABMTM, MTTA, and MTA, and the Japan Machine Tool Builders' Association (JMTBA).
Just as machine tool builders have long had trade associations, so have machine tool distributors (dealers). Examples have been the American Machine Tool Distributors’ Association (AMTDA) and the Japan Machine Tool Trade Association (JMTTA). In recent decades the builders' and distributors' associations have cooperated on shared interests to the extent that some of them have merged. For example, the former NMTBA and AMTDA have merged into the AMT.
Trade shows.
Major trade shows of the industry include IMTS (International Manufacturing Technology Show, formerly called the International Machine Tool Show) and EMO (French "Exposition Mondiale de la Machine Outil", English "Machine Tool World Exposition"). There are also many smaller trade shows concentrating on specific geographical regions (for example, the Western US, the mid-Atlantic US, the Ruhr Valley, or the Tokyo region) or on specific industries (such as shows tailored especially to the moldmaking industry).
Historical studies of machine tool building.
In the early 20th century, Joseph Wickham Roe wrote a seminal classic of machine tool history, "English and American Tool Builders" (1916), which is extensively cited by later works. About 20 years later Roe published a biography of James Hartness (1937) that also contains some general history of the industry. In 1947, Fred H. Colvin published a memoir, "Sixty Years with Men and Machines", that contains quite a bit of general history of the industry.
L. T. C. Rolt's 1965 monograph, "A Short History of Machine Tools", is a widely read classic, as are the series of monographs that Robert S. Woodbury published during the 1960s, which were collected into a volume in 1972 as "Studies in the History of Machine Tools".
In 1970, Wayne R. Moore wrote about the Moore family firm, the Moore Special Tool Company, who independently invented the jig borer (contemporaneously with its Swiss invention). Moore's monograph, "Foundations of Mechanical Accuracy", is a seminal classic of the principles of machine tool design and construction that yield the highest possible accuracy and precision in machine tools (second only to that of metrological machines). The Moore firm epitomized the art and science of the tool and die maker.
David F. Noble's "Forces of Production" (1984) is one of the most detailed histories of the machine tool industry from World War II through the early 1980s, relayed in the context of the social impact of evolving automation via NC and CNC. Also in 1984, David A. Hounshell published "From the American System to Mass Production", one of the most detailed histories of the machine tool industry from the late 18th century through 1932. It does not concentrate on listing firm names and sales statistics (which Floud's 1976 monograph focuses on) but rather is extremely detailed in exploring the development and spread of practicable interchangeability, and the thinking behind the intermediate steps. It is extensively cited by later works.
In 1989, Holland published a history, "When the Machine Stopped", that is most specifically about Burgmaster (which specialized in turret drills); but in telling Burgmaster's story, and that of its acquirer Houdaille, Holland provides a history of the machine tool industry in general between World War II and the 1980s that ranks with Noble's coverage of the same era (Noble 1984) as a seminal history. It was later republished under the title "From Industry to Alchemy".


Learning Factory

Learning factories represent a realistic manufacturing environment for education, training, and research. In the last decades, numerous learning factories have been built in academia and industry.
Definition.
The term learning factory consists of two words. The word ‘learning’ indicates the development of competencies, while the word ‘factory’ defines a realistic manufacturing environment. The generally accepted definition was agreed within the CIRP CWG and published in the CIRP Encyclopedia: According to the International Academy for Production Engineering (CIRP) a learning factory is defined by
Depending on the purpose of the learning factory, learning takes place through teaching, training and/or research. Consequently, learning outcomes may be competency development and/or innovation. An operating model ensuring the sustained operation of the learning factory is desirable.
The difference between learning factories and model factories is that learning factories provide a didactical concept and an operating model for training.
History.
The term ‘learning factory’ was first coined in the US in 1994, when the National Science Foundation (NSF) awarded a consortium of the Penn State University. Industry-related design projects have been supported on a 2000 m² facility with machines, tools, and materials. Real problems of the industry could be solved in a realistic environment. In 2006, the program received the National Academy of Engineering’s Gordon Prize for Innovation in Engineering Education. In Europe, more and more learning factories have been designed in the last decade. One of the first learning factories in this wave is the ‘Center for industrial Productivity’ founded by the Institute for Production Management, Technology and Machine Tools (Technische Universität Darmstadt), established in 2007 (see section 3). In 2011, the Initiative on ‘European Learning Factories’ was established with the 1st Conference on Learning Factories in Darmstadt (Germany). The Initiative has led to a European collaboration on the topic of learning factories. In 2017, the initiative decided to include learning factories from all continents and renamed itself to the ‘International Association of Learning Factories’.
Examples of existing learning factories.
Learning factories in academia.
TU Darmstadt: Process Learning Factory CiP.
In the Process Learning Factory CiP of the Technische Universität Darmstadt focuses on developing competencies for lean production and Industrie 4.0. It has been established in 2007. The delivery of raw material, machining, quality control, assembly, packing, and indirect processes are simulated similar to a small and medium-sized enterprise . Besides the eight variants of the pneumatic cylinder, customer-individualized requirements of different measurements are implemented in a lean machining area. On about 500 m², learners apply lean methods and solve problems on own experience. The learning factory can map different scenarios from a wasteful and unbalanced production environment to a lean and a digital lean state. The 15 different learning modules are structured in lean basics, lean core elements and lean thinking. Within a learning module, practical experiences alternate with theoretical teaching. The Process Learning Factory CiP is a part of the SME competency center for the Rhine-Main area funded by the German Federal Ministry for Economic Affairs and Energy. With new implemented Industrie 4.0-technologies the concept of lean is extended. Different technologies are implemented, e.g. product traceability, worker assistance, digital shopfloor management, predictive maintenance, milk run 4.0 and AGVs. With each implemented technology new topics for the learning modules are integrated. Furthermore, the operating institute has established many learning factories for academia and industry worldwide.
Technische Universität Wien: Pilot Factory.
In the TU Wien Pilot Factory focuses on Industrie 4.0. It is a realistic test environment with real machines, real production chains, and a real product. On 900 m² a 3D printer is produced that uses the principle of fused deposition modeling. The printer dimensions can be configured on customer requirements. Different Industrie 4.0-concepts are integrated, e.g. process and layout adaptivity, a high degree of human-machine interaction, and use of data analytics for transparency and optimization. AGV transportation connects the manufacturing with the assembly area. The material is replenished automatically. Furthermore, operators are assisted with collaborative robots, assistance systems, sensor technology, and image processing.
Stellenbosch University: Stellenbosch Learning Factory.
The Stellenbosch Learning Factory of the Stellenbosch University provides trainings for lean operations, ergonomics and is a research platform for Industrie 4.0. The target groups are industry partners and students for industrial engineering. New developments include a double degree M.Sc. Program with the Reutlingen University. German students have the possibility to visit a summer school. In the learning factory a RFID track and trace-system and a real time KPI visualization are integrated. The product of the Stellenbosch University is a O-scale train set.
University of Windsor: iFactory.
The iFactory of the University of Windsor has the main topics integrated product – systems learning and Industrie 4.0. Desksets and automobile belt tensioners are assembled on 200 sqm. The tracking of processes and production operations planning and scheduling is possible with RFID tags. The complete system is modular and reconfigurable with equipment from FESTO Didactic. The main purpose of the learning factory is research, teaching and demonstration for students and industry. The learning factory was set up in 2011 and is the first of its kind in North America.
Université du Luxembourg: Operational Excellence Laboratory.
The Operational Excellence Laboratory of the Université du Luxembourg is place for industrial partners to get hands-on experience of lean tools and demonstrate new technology related to Industrie 4.0. Examples for new technologies are the integration of RFID, augmented reality and digital manuals. Furthermore engineering master students are trained. The learning factory is a platform for retrofitting new technological features to develop, analyze and validate their usability in assembly or disasssembly lines. The product of the learning factory is a hole puncher.
Technische Universität München: Learning Factory for Lean Production (LSP).
The focus of the Learning Factory for Lean production (LSP) at the TU München is lean production. The manufactured product is a real gearbox with 24 variants. The facility consists of an assembly area, a kaizen workshop area, and a theoretical teaching area. The processes logistics, assembly, quality control and packaging are mapped. A typical lean journey is recreated during the course: from an unsatisfying situation to a lean state. The theory is taught in theory lessons slots. Four to six trainings are offered every year. The mobile equipment can be transported to any location.
Ruhr-Universität Bochum: LPS Learning Factory.
The main topics of the LPS Learning Factory are lean production, Industrie 4.0 and resource efficiency. It was established in 2009 by the Ruhr Universität Bochum. Bottle caps, bottle cap holders and various make-to-order products are manufactured on 1800 m². The production environment includes various machine tools, load transports, manual assembly stations, and various industrial robots. The main topics are lean production, Industrie 4.0 and resource efficiency. Every year 900 students are practicing exercises. Real products that are purchased for the industry are produced. Besides that, numerous research projects take place in the learning factory, e.g. Industrie 4.0 maturity model, assistance and learning systems, cyber-physical production systems and industrial robotics. Since 2018 the learning factory is part of the SME 4.0 competence center Siegen.
Hochschule Reutlingen: Werk150.
The Werk150 (formerly ESB Logistics Learning Factory) at ESB Business School is an authentic learning, development and research environment. The facility, which was started in 2014, provides a cutting-edge infrastructure for the training and advanced training of students. Moreover, topical issues of applied research are also addressed, and new methods, tools and future technologies as well as control methods for adaptable work and logistics systems are developed and tested. The results of the applied research are continuously integrated in the course activities. The Werk150 images a model production company with its entire industrial value chain and a changing product and services portfolio. Especially processes in the areas of product and work system engineering, incoming goods, storage, order picking, production, assembly and additive manufacturing as well as distribution are replicated and looked at in their entirety.
In the Werk150 the requirements and influences from Industry 4.0 are investigated and conveyed in teaching and further training courses. It has a digital twin or image that is linked with a real factory using information and communication technologies. Thus, both products and production can be planned and simulated virtually, production controlled digitally and the status and localisation of orders, parts and resources monitored in real time.
Dresden University of Technology: Process-to-Order Lab (P2O-Lab).
The P2O-Lab is a 110 m² learning factory on the premises of the Dresden University of Technology. Building on solution approaches from the fields of modularization, digitization and artificial intelligence, the P2O-Lab investigates the next steps to serve highly variable markets with almost binary product life cycles. The P2O Lab asks itself which requirements, models, methods, and tools must be fulfilled for this. As an accompanying UserStory, the goal is to derive, evaluate and implement a suitable process from existing plant modules directly from the product order. The findings from the current research are subsequently flowing into the teaching of the Faculty of Electrical Engineering at the TU Dresden. In addition, students as well as external persons have the opportunity to gain hands-on experience in the P2O-Lab in the context of workshops and internships.
Learning factories in industry.
MPS Lernplattform.
Since 2011, the MPS Lernplattform of the Daimler AG manufactures different products on 3000 m² with the main topic of lean production. The original components of the production as well as 1:10 models with several simulations are used. A press shop, body shop, paint shop, assembly and logistics as parts of the automobile industry are simulated. The assembled products can be reused after the training: e.g. roof control units, sun visors, covers, floor mats or room tears. Qualified in-house employees carry out the training who have didactical background knowledge as well as long-term experience in the production area. The training consists of 20% theory and 80% practice. More than ten different learning modules are offered for participants who take important insights to their daily work. The MPS Lernplattform increasingly relies on cooperation with external partners such as the TU Darmstadt.
Festo Learning Factory Scharnhausen.
The Festo Learning Factory in Scharnhausen is operated by Festo AG since 2014 with four different topics: mechanical processing (1), valve and valve terminal assembly (2), automation and process improvement (4), administration of the learning factory (4). Pneumatic valves and valve terminals are manufactured on 220 m² on four rooms. More than forty learning modules are offered on fourteen different workplaces. The participants are exclusively from Festo, especially for the training of new operators and advanced qualification of incumbent workers. Each team leader or a qualified team specialist trains the operators by themselves. Therefore ‘Train-the-trainer’-modules have been developed. The trainings are developed continuously. New products, new processes, new production equipment are integrated.
Approach to Competency-Oriented Planning and Design.
The concept of learning factories offers potentials to former didactical and technical approaches. Through the realistic environment, learners are more motivated and the development of competencies facilitates. Problem-based, project-based or research-based learning is possible. Action-oriented learning results in significant advantages compared to traditional teaching methods. Methods, innovations, and technologies can be transferred to the industry more easily. Through learning factories learners can apply methods on a realistic production environment without the negative effect of stopping production lines in their own enterprise.
Learning Factories are designed on three design levels:
More details about the design process of learning factories can be seen in the dissertation of Michael Tisch with the title “Modellbasierte Methodik zur kompetenzorientierten Gestaltung von Lernfabriken für die schlanke Produktion”.
Limitations of learning factories.
The learning factory concept is also limited. The planning, development, construction, and operation of learning factories require financial and personnel resources. Physical learning factories need space in a facility. Machines, workplaces, and other factory elements must be purchased and maintained. Partners and personnel should be willing and able to participate in a learning factory. The sustainability must be ensured through an operating model. Furthermore, learning factories map limited sections of production environments. A single learning factory is not able to provide a suitable, general environment for all challenges in academia and industry. Specific industrial sectors, addressed topics, single production processes, company departments, and target groups are addressed. The mapping abilities of learning factories are limited.


Savita Oil Technologies Limited

Savita Oil Technologies Limited  (formerly known as Savita Chemical) is an Indian automotive, industrial lubricant and petroleum specialty oils production company with its headquarters at Mumbai, Maharashtra. It has primarily engaged in manufacturing of petroleum specialties such as transformer oils, liquid paraffin and white oils, petroleum jellies, synthetic petroleum sulfonates and other specialties. Savita Oil has been ranked "#42" in Fortune Next 500 list under lube oil and lubricants category, by Fortune India.
The company is also involved in manufacturing of automotive and industrial lubricants. In 2018, the company relaunched Savsol, a domestic brand of lubricants and engine oils.
History.
The company has been listed on Bombay Stock Exchange and National Stock Exchange since 1994.
It operates three manufacturing plants in Western India. Its Lube Oil manufacturing plant situated at Silvassa, is a fully automated manufacturing unit and has been certified for ISO 9001:2015 & ISO 14001:2015.
Partnership.
In 2018, Tata Motors signed an agreement with Savita Oil Technologies to manufacture and provide original oils for their passenger vehicle brands.


Athletics at the 1971 Mediterranean Games – Results

These are the partial results of the athletics competition at the 1971 Mediterranean Games taking place between 12 and 17 October in Izmir, Turkey.
Men's results.
100 meters.
Heats – 12 OctoberWind:
Final – 13 OctoberWind: +0.1 m/s
200 meters.
HeatsWind:
Final – 16 OctoberWind: +0.1 m/s
400 meters.
Heats – 13 October
Final – 14 October
800 meters.
Heats – 15 October
Final – 16 October
1500 meters.
Heats – 12 October
Final – 13 October
5000 meters.
Heats – 12 October
Final – 14 October
10,000 meters.
16 October
Marathon.
17 October
110 meters hurdles.
Heats – 14 OctoberWind:
Final – 15 OctoberWind: +0.3 m/s
400 meters hurdles.
Heats – 12 October
Final – 13 October
3000 meters steeplechase.
16 October
4 × 100 meters relay.
15 October
4 × 400 meters relay.
16 October
20 kilometers walk.
12 October
50 kilometers walk.
14 October
High jump.
16 October
Pole vault.
15 October
Long jump.
13 October
Triple jump.
15 October
Shot put.
12 October
Discus throw.
14 October
Hammer throw.
15 October
Javelin throw.
16 October
Decathlon.
13–14 October
Women's results.
100 meters.
Heats – 12 October
Final – 13 October
400 meters.
16 October
800 meters.
14 October
1500 meters.
15 October
100 meters hurdles.
Heats – 13 October
Final – 14 October
4 × 100 meters relay.
15 October
High jump.
15 October
Discus throw.
12 October


Ensinger (company)

The Ensinger Group is engaged in the development and manufacture of compounds, semi-finished products, technical parts, composite materials and profiles made of engineering and high-performance plastics. The family-owned enterprise is represented in major industrial regions with manufacturing facilities or sales offices. The main office is located in Nufringen/Baden-Württemberg, Germany.
History.
The company was founded in 1966 by Wilfried Ensinger. First areas of focus included the manufacture and sale of thermoplastic engineering plastics. Closely linked with this technology, the company worked on further development of the extrusion process and application technology. A short time after relocation of the headquarters to Nufringen, Ensinger launched the production of components manufactured by machining semi-finished products. In 1977, the company dispatched its first volume-produced thermal insulating profiles made of glass fibre-reinforced polyamide 6.6 to manufacturers of aluminium windows. A second plant was erected in 1980 in Cham/Bavaria. After the launch of other product lines, Ensinger founded a number of additional subsidiaries in Europe, North America, South America and Asia. Since 2007 the company has been present in China with its own production facility.
Business field.
The products are used in a wide variety of industrial sectors, including mechanical engineering, in the automotive and aviation industry and in medical technology. The technical solutions based on thermoplastic polymers are also very common in the food industry and in electrical and semiconductor technology. In many cases, high -performance plastics replace other materials such as metals or ceramics. The segment disc distance made of insulating plastic for insulating glass was sold to the Fenzi Group in 2019.
Locations.
The company group employs a total workforce of ca. 2,700 in 33 locations.
Production sites.
The company also owns subsidiaries in Denmark, Poland, Sweden, Spain, Czech Republic, Turkey, Japan, Singapore, Vietnam, India, Taiwan and South Korea.
Business segments.
To process the thermoplastic polymers, Ensinger uses a number of production methods, in particular compounding, extrusion, machining, injection moulding, casting, sintering and compression molding.
The spectrum of materials used ranges from engineering plastics (such as PA, PET and POM) through to the category of highly temperature-resistant high-performance plastics (such as PEEK, PPS, and PI).
Thermoplastic polymer products are used in different fields, including the automotive and aerospace industries, mechanical engineering, medical technology, the electrical and semiconductor sectors and food industry.
On 1 February 2022, it was announced Ensinger had concluded a joint agreement to acquire INEOS Styrolution's "StyLight" thermoplastic composite materials business.


Design to standards

"Design to Standards" means to design items with generally accepted and uniform procedures, dimensions or materials.
Benefits.
Product standardization is a technique in engineering design that aim to reduce the number of different parts within a product. The benefits are:
The supply chain costs are simple to reason:
Product platforms are enabled through:
The product design process becomes faster because:
Standards.
Standardization can occur through two ways


Time metrology

Time metrology or time and frequency metrology is the application of metrology for time keeping, including frequency stability.
Its main tasks are the realization of the second as the SI unit of measurement for time and the establishment of time standards and frequency standards as well as their dissemination.


Moscow Aircraft Production Association

MAPO - the Moscow Aircraft Production Association  was a major Russian state-owned military aircraft manufacturer.
History.
MAPO has its origins in Plant #30 of the Dux Factory company. Plant #30 was established in 1939 in Dubna. In December 1941, it was relocated to the former site of Plant #1, where it manufactured the Ilyushin Il-2. In 1950, it merged with Plant #381, to produce the Il-28 in larger volumes. In 1953, Lukhovitsy Machine Building Plant was established as a subsidiary of the plant.
Plant #30 became known as the "Znamya Truda Machine-Building Plant" in 1965, and as the Moscow Aircraft Production Organisation in 1973.
In the early 1990s, it employed 30,000 workers. In 1995, MAPO was merged with the Mikoyan Design Bureau, forming MAPO-MiG. In January 1996, a decree of President Boris Yeltsin established MAPO VPK, which combined 12 different aviation companies, including MAPO-MiG, Kamov, Klimov, the Chernyshev Machine Building Enterprise and Aviabank.
Unlike Sukhoi, which managed to secure export contracts with China and India, MAPO continued to be unprofitable throughout the 1990s. In December 1999, MAPO was renamed Russian Aircraft Corporation MiG.
In 2006, MAPO merged with Sukhoi and several other Russian aviation companies to form United Aircraft Corporation. The majority of MAPO's former assets are now part of Mikoyan.
The Lukhovitsy and Znamya Truda plants are currently known as 'MiG Manufacturing Complex №1' (ПК №1 PCK «МиГ») and 'MiG Manufacturing Complex №2' (ПК №2 PCK «МиГ»), respectively.
Names.
Over the years, it has also been known as OSOAVIAKHIM Plant #1, GAZ No. 1, Menjinski Plant #39, Orjonikidze Plant #381, Plant #30, MMZ (Moscow Machine-Building Plant) "Znamya Truda" (Banner of Labor), P.A. Voronin Production Center, and "Moscow Aircraft Production Organization (MAPO) named after Dementiev" (, Minister of Aircraft Industry from 1953 to 1977).


Roller screw

A roller screw, also known as a planetary roller screw or satellite roller screw, is a low-friction precision screw-type actuator, a mechanical device for converting rotational motion to linear motion, or vice versa. Planetary roller screws are used as the actuating mechanism in many electro-mechanical linear actuators. Due to its complexity the roller screw is a relatively expensive actuator (as much as an order of magnitude more expensive than ball screws), but may be suitable for high-precision, high-speed, heavy-load, long-life and heavy-use applications.
Roller screw mechanisms are commonly incorporated into motion/positioning systems in a variety of industries such as manufacturing and aerospace.
Principle of operation.
A roller screw is a mechanical actuator similar to a ball screw that uses rollers as the load transfer elements between nut and screw instead of balls. The rollers are typically threaded but may also be grooved depending on roller screw type. Providing more bearing points than ball screws within a given volume, roller screws can be more compact for a given load capacity while providing similar efficiency (75%-90%) at low to moderate speeds, and maintain relatively high efficiency at high speeds. Roller screws can surpass ball screws in regard to positioning precision, load rating, rigidity, speed, acceleration, and lifetime. Standard roller screw actuators can achieve dynamic load ratings above 130 tons of force (exceeded in single-unit actuator capacity only by hydraulic cylinders).
The three main elements of a typical planetary roller screw are the screw shaft, nut and planetary roller. The screw, a shaft with a multi-start V-shaped thread, provides a helical raceway for multiple rollers radially arrayed around the screw and encapsulated by a threaded nut. The thread of the screw is typically identical to the internal thread of the nut. The rollers spin in contact with, and serve as low-friction transmission elements between screw and nut. The rollers typically have a single-start thread with convex flanks that limit friction at the rollers' contacts with screw and nut. The rollers typically orbit the screw as they spin (in the manner of planet gears to sun gear), and are thus known as planetary, or satellite, rollers. As with a lead screw or ball screw, rotation of the nut results in screw travel, and rotation of the screw results in nut travel.
For a given screw diameter and quantity of thread starts more rollers corresponds to higher static load capacity, but not necessarily to a higher dynamic load capacity. Preloaded split nuts and double nuts are available to eliminate backlash.
Planetary roller screw types.
Carl Bruno Strandgren developed some of the earliest effective forms of roller screws and applied for a patent in Nice, France in February 1942. The French patent #888.281 was granted in August 1943 and published in December of the same year. The first commercial Roller Screw was designed and manufactured under his supervision in 1949 and was mounted on a narrow gauge locomotive which operated in a northern France coal mine. Subsequent units were produced and mounted on machine-tools and starting in 1955 on aircraft. At that time Carl Bruno Strandgren applied for a new patent incorporating detailed calculations and detailed manufacturing considerations for which he was awarded US patents for such a “Screw-Threaded Mechanism” in 1954, and “Nut and Screw Devices” and the "Roller Screw" in 1965.
Roller screw types are defined by the motion of the rollers relative to the nut and screw. The four commercially available types of roller screw are "standard", "inverted", "recirculating", and "bearing ring".
"Differential roller screws", typically variants of the standard and recirculating types, are also commercially available. Differential roller screws modify the rotational speed ratios between the rollers and the screw by varying the flank angles and contact points of the threads or grooves. In that way differential roller screws change the effective lead of the screw. William J. Roantree received a US patent for the "Differential Roller Nut" in 1968.
Standard planetary roller screw.
The standard planetary roller screw is also known as the non-recirculating roller screw. The lack of axial movement of the roller relative to the nut, and the gearing of rollers to nut, are definitive of the standard type of roller screw.
The nut and screw have identical multiple-start threads. The rollers have a single-start thread with an angle matching the nut thread. The matched thread angle prevents axial movement between the nut and the roller as the rollers spin. The nut assembly includes spacer rings and ring gears that position and guide the rollers. The spacer rings, which rotate within the ring gears, have equidistant holes that act as rotary bearings for the smooth pivot ends (studs) of the rollers. The ring gears time the spinning and orbit of the rollers about the screw axis by engaging gear teeth near the ends of the rollers. The spacer rings rotate on axis with the screw in unison with the orbit of the rollers. The spacer rings float relative to the nut, axially secured by retaining rings, because they spin around the screw at a lower frequency (angular velocity) than the nut.
Configuration.
Standard roller screws are typically identified by screw diameter (typically ranging from 3.5mm – 200mm) and lead (1mm – 62mm). The threading of the screw (3 – 6 starts) is either rolled (lower capacity) or ground (higher capacity). The diameters of the nut and rollers (7 – 14 in quantity) are simple functions of the screw diameter and lead.
Where:
The following relationships apply to standard and inverted roller screws:
For example, if
then
Inverted roller screw.
The inverted planetary roller screw is also known as the reverse roller screw. The lack of axial movement of the roller relative to the screw, and the gearing of rollers to screw, are definitive of the inverted type of planetary roller screw. This type of roller screw was developed simultaneously with the standard roller screw.
Inverted roller screws operate on the same principles of standard roller screws except that the function of the nut and screw is reversed in relation to the rollers. The rollers move axially within the nut, which is elongated to accommodate the full extent of screw shaft travel. The threaded portion of the screw shaft is limited to the threaded length of the rollers. The non-threaded portion of the screw shaft can be a smooth or non-cylindrical shape. The ring gear is replaced by gear teeth above and below the threaded portion of the screw shaft.
Aside from the inversion of the relationship of rollers to nut and screw, the configuration and relationships of inverted roller screws match those of standard roller screws.
Recirculating roller screw.
The recirculating type of planetary roller screw is also known as a recycling roller screw. A recirculating roller screw can provide a very high degree of positional accuracy by using minimal thread leads. The rollers of a recirculating roller screw move axially within the nut until being reset after one orbit about the screw. Recirculating roller screws do not employ ring gears. Carl Bruno Strandgren was awarded a US Patent for the recirculating roller screw in 1965.
The screw and nut may have very fine identical single- or two-start threads. Recirculating rollers are grooved (instead of threaded) so they move axially during spinning engagement with the threads of the nut and screw, shifting up or down by one lead of thread after completing an orbit around the screw. The nut assembly typically includes a slotted cage and cam rings. The cage captivates the rollers in elongated slots, equally spacing the rollers while permitting rotation and axial motion of the rollers. The cam rings have opposing cams aligned with an axial groove in the wall of the nut. After a roller completes an orbit about the nut it is released into the groove, disengages from nut and screw, and is pushed between the cams to the axial midpoint of the nut assembly (shifting by a distance equal to the lead of the screw). Returned to its starting position, and reengaged to nut and screw, the roller may then orbit the screw once again.
In 2006, Charles C. Cornelius and Shawn P. Lawlor received a patent for a cage-less recirculating roller screw system. As with the traditional recirculating roller screw system, rollers disengage from the screw when they come upon an axial groove in the wall of the nut. The system differs in that the rollers are continually engaged by the nut, and the axial groove of the nut is threaded. Non-helical threads in the axial groove of the nut return the roller to its axial starting position (after completion of an orbit). Non-circular compression rings, or cam rings, at opposite ends of the rollers (roller axles) apply constant pressure between rollers and nut, synchronizing roller rotation and thrusting the rollers into the nut's axial groove. Lacking ring gears and roller cage, cage-less recirculating roller screws can be relatively efficient and, as a result, permit higher dynamic capacities for some screw shaft diameters.
Bearing ring roller screw.
In 1986 Oliver Saari was awarded a patent for a bearing ring roller screw, commonly referred to by its trademark, Spiracon. This type matches the orbit of the rollers to the rotation of the nut assembly. The actuator contains more load transfer elements than the other types, a bearing ring and thrust bearings, but manufacture of component parts is relatively simple (e.g. gearing teeth may be eliminated).
In the other roller screw types above, loads are transferred from the nut through the rollers to the screw (or in the reverse order). In this type of actuator, thrust bearings and a freely rotating internally grooved bearing ring transfer loads between the rollers and the nut.
The screw has a multi-start thread. The rollers and encapsulating rotating ring are identically grooved, not threaded, so there is no axial movement between the two. The nut assembly includes a cylindrical housing capped by non-rotating spacer rings. The spacer rings have equidistant holes that act as rotary bearings for the smooth pivot ends (studs) of the rollers. Roller-type thrust bearings between the spacer rings and bearing ring permit free rotation of the bearing ring while transferring the axial load between the two.
The rollers act as the “threads” of the nut assembly, causing axial movement of the rotating screw due to their orbital restraint. Screw rotation spins the rollers, which spin the bearing ring, dissipating the load-induced friction along the way.
Timothy A. Erhart was awarded a US patent in 1996 for a linear actuator effectively incorporating an inverted bearing ring roller screw. The screw shaft is grooved the length of and to match the grooved rollers, which travel with the shaft. The bearing ring is elongated and internally threaded for the length of screw shaft travel. The nut assembly housing and sealed end ring forms the exterior of the actuator assembly.


Failure of electronic components

Electronic components have a wide range of failure modes. These can be classified in various ways, such as by time or cause. Failures can be caused by excess temperature, excess current or voltage, ionizing radiation, mechanical shock, stress or impact, and many other causes. In semiconductor devices, problems in the device package may cause failures due to contamination, mechanical stress of the device, or open or short circuits.
Failures most commonly occur near the beginning and near the ending of the lifetime of the parts, resulting in the bathtub curve graph of failure rates. Burn-in procedures are used to detect early failures. In semiconductor devices, parasitic structures, irrelevant for normal operation, become important in the context of failures; they can be both a source and protection against failure.
Applications such as aerospace systems, life support systems, telecommunications, railway signals, and computers use great numbers of individual electronic components. Analysis of the statistical properties of failures can give guidance in designs to establish a given level of reliability. For example, power-handling ability of a resistor may be greatly derated when applied in high-altitude aircraft to obtain adequate service life.
A sudden fail-open fault can cause multiple secondary failures if it is fast and the circuit contains an inductance; this causes large voltage spikes, which may exceed 500 volts. A broken metallisation on a chip may thus cause secondary overvoltage damage. Thermal runaway can cause sudden failures including melting, fire or explosions.
Packaging failures.
The majority of electronic parts failures are packaging-related. Packaging, as the barrier between electronic parts and the environment, is very susceptible to environmental factors. Thermal expansion produces mechanical stresses that may cause material fatigue, especially when the thermal expansion coefficients of the materials are different. Humidity and aggressive chemicals can cause corrosion of the packaging materials and leads, potentially breaking them and damaging the inside parts, leading to electrical failure. Exceeding the allowed environmental temperature range can cause overstressing of wire bonds, thus tearing the connections loose, cracking the semiconductor dies, or causing packaging cracks. Humidity and subsequent high temperature heating may also cause cracking, as may mechanical damage or shock.
During encapsulation, bonding wires can be severed, shorted, or touch the chip die, usually at the edge. Dies can crack due to mechanical overstress or thermal shock; defects introduced during processing, like scribing, can develop into fractures. Lead frames may contain excessive material or burrs, causing shorts. Ionic contaminants like alkali metals and halogens can migrate from the packaging materials to the semiconductor dies, causing corrosion or parameter deterioration. Glass-metal seals commonly fail by forming radial cracks that originate at the pin-glass interface and permeate outwards; other causes include a weak oxide layer on the interface and poor formation of a glass meniscus around the pin.
Various gases may be present in the package cavity, either as impurities trapped during manufacturing, outgassing of the materials used, or chemical reactions, as is when the packaging material gets overheated (the products are often ionic and facilitate corrosion with delayed failure). To detect this, helium is often in the inert atmosphere inside the packaging as a tracer gas to detect leaks during testing. Carbon dioxide and hydrogen may form from organic materials, moisture is outgassed by polymers and amine-cured epoxies outgas ammonia. Formation of cracks and intermetallic growth in die attachments may lead to formation of voids and delamination, impairing heat transfer from the chip die to the substrate and heatsink and causing a thermal failure. As some semiconductors like silicon and gallium arsenide are infrared-transparent, infrared microscopy can check the integrity of die bonding and under-die structures.
Red phosphorus, used as a charring-promoter flame retardant, facilitates silver migration when present in packaging. It is normally coated with aluminium hydroxide; if the coating is incomplete, the phosphorus particles oxidize to the highly hygroscopic phosphorus pentoxide, which reacts with moisture to phosphoric acid. This is a corrosive electrolyte that in the presence of electric fields facilitates dissolution and migration of silver, short-circuiting adjacent packaging pins, lead frame leads, tie bars, chip mount structures, and chip pads. The silver bridge may be interrupted by thermal expansion of the package; thus, disappearance of the shorting when the chip is heated and its reappearance after cooling is an indication of this problem. Delamination and thermal expansion may move the chip die relative to the packaging, deforming and possibly shorting or cracking the bonding wires.
Contact failures.
Electrical contacts exhibit ubiquitous contact resistance, the magnitude of which is governed by surface structure and the composition of surface layers. Ideally contact resistance should be low and stable, however weak contact pressure, mechanical vibration, corrosion, and the formation of passivizing oxide layers and contacts can alter contact resistance significantly, leading to resistance heating and circuit failure.
Soldered joints can fail in many ways like electromigration and formation of brittle intermetallic layers. Some failures show only at extreme joint temperatures, hindering troubleshooting. Thermal expansion mismatch between the printed circuit board material and its packaging strains the part-to-board bonds; while leaded parts can absorb the strain by bending, leadless parts rely on the solder to absorb stresses. Thermal cycling may lead to fatigue cracking of the solder joints, especially with elastic solders; various approaches are used to mitigate such incidents. Loose particles, like bonding wire and weld flash, can form in the device cavity and migrate inside the packaging, causing often intermittent and shock-sensitive shorts. Corrosion may cause buildup of oxides and other nonconductive products on the contact surfaces. When closed, these then show unacceptably high resistance; they may also migrate and cause shorts. Tin whiskers can form on tin-coated metals like the internal side of the packagings; loose whiskers then can cause intermittent short circuits inside the packaging. Cables, in addition to the methods described above, may fail by fraying and fire damage.
Printed circuit board failures.
Printed circuit boards (PCBs) are vulnerable to environmental influences; for example, the traces are corrosion-prone and may be improperly etched leaving partial shorts, while the vias may be insufficiently plated through or filled with solder. The traces may crack under mechanical loads, often resulting in unreliable PCB operation. Residues of solder flux may facilitate corrosion; those of other materials on PCBs can cause electrical leaks. Polar covalent compounds can attract moisture like antistatic agents, forming a thin layer of conductive moisture between the traces; ionic compounds like chlorides tend to facilitate corrosion. Alkali metal ions may migrate through plastic packaging and influence the functioning of semiconductors. Chlorinated hydrocarbon residues may hydrolyze and release corrosive chlorides; these are problems that occur after years. Polar molecules may dissipate high-frequency energy, causing parasitic dielectric losses.
Above the glass transition temperature of PCBs, the resin matrix softens and becomes susceptible contaminant diffusion. For example, polyglycols from the solder flux can enter the board and increase its humidity intake, with corresponding deterioration of dielectric and corrosion properties. Multi-layer substrates using ceramics suffer from many of the same problems.
Conductive anodic filaments (CAFs) may grow within the boards along the fibers of the composite material. Metal is introduced to a vulnerable surface typically from plating the vias, then migrates in presence of ions, moisture, and electrical potential; drilling damage and poor glass-resin bonding promotes such failures. The formation of CAFs usually begins by poor glass-resin bonding; a layer of adsorbed moisture then provides a channel through which ions and corrosion products migrate. In presence of chloride ions, the precipitated material is atacamite; its semiconductive properties lead to increased current leakage, deteriorated dielectric strength, and short circuits between traces. Absorbed glycols from flux residues aggravate the problem. The difference in thermal expansion of the fibers and the matrix weakens the bond when the board is soldered; the lead-free solders which require higher soldering temperatures increase the occurrence of CAFs. Besides this, CAFs depend on absorbed humidity; below a certain threshold, they do not occur. Delamination may occur to separate the board layers, cracking the vias and conductors to introduce pathways for corrosive contaminants and migration of conductive species.
Relay failures.
Every time the contacts of an electromechanical relay or contactor are opened or closed, there is a certain amount of contact wear. An electric arc occurs between the contact points (electrodes) both during the transition from closed to open (break) or from open to closed (make). The arc caused during the contact break (break arc) is akin to arc welding, as the break arc is typically more energetic and more destructive.
The heat and current of the electrical arc across the contacts creates specific cone & crater formations from metal migration. In addition to the physical contact damage, there appears also a coating of carbon and other matter. This degradation drastically limits the overall operating life of a relay or contactor to a range of perhaps 100,000 operations, a level representing 1% or less than the mechanical life expectancy of the same device.
Semiconductor failures.
Many failures result in generation of hot electrons. These are observable under an optical microscope, as they generate near-infrared photons detectable by a CCD camera. Latchups can be observed this way. If visible, the location of failure may present clues to the nature of the overstress. Liquid crystal coatings can be used for localization of faults: cholesteric liquid crystals are thermochromic and are used for visualisation of locations of heat production on the chips, while nematic liquid crystals respond to voltage and are used for visualising current leaks through oxide defects and of charge states on the chip surface (particularly logical states). Laser marking of plastic-encapsulated packages may damage the chip if glass spheres in the packaging line up and direct the laser to the chip.
Examples of semiconductor failures relating to semiconductor crystals include:
Parameter failures.
Vias are a common source of unwanted serial resistance on chips; defective vias show unacceptably high resistance and therefore increase propagation delays. As their resistivity drops with increasing temperature, degradation of the maximum operating frequency of the chip the other way is an indicator of such a fault. "Mousebites" are regions where metallization has a decreased width; such defects usually do not show during electrical testing but present a major reliability risk. Increased current density in the mousebite can aggravate electromigration problems; a large degree of voiding is needed to create a temperature-sensitive propagation delay.
Sometimes, circuit tolerances can make erratic behaviour difficult to trace; for example, a weak driver transistor, a higher series resistance and the capacitance of the gate of the subsequent transistor may be within tolerance but can significantly increase signal propagation delay. These can manifest only at specific environmental conditions, high clock speeds, low power supply voltages, and sometimes specific circuit signal states; significant variations can occur on a single die. Overstress-induced damage like ohmic shunts or a reduced transistor output current can increase such delays, leading to erratic behavior. As propagation delays depend heavily on supply voltage, tolerance-bound fluctuations of the latter can trigger such behavior.
Gallium arsenide monolithic microwave integrated circuits can have these failures:
Metallisation failures.
Metallisation failures are more common and serious causes of FET transistor degradation than material processes; amorphous materials have no grain boundaries, hindering interdiffusion and corrosion. Examples of such failures include:
Electrical overstress.
Most stress-related semiconductor failures are electrothermal in nature microscopically; locally increased temperatures can lead to immediate failure by melting or vaporising metallisation layers, melting the semiconductor or by changing structures. Diffusion and electromigration tend to be accelerated by high temperatures, shortening the lifetime of the device; damage to junctions not leading to immediate failure may manifest as altered current–voltage characteristics of the junctions. Electrical overstress failures can be classified as thermally-induced, electromigration-related and electric field-related failures; examples of such failures include:
Electrostatic discharge.
Electrostatic discharge (ESD) is a subclass of electrical overstress and may cause immediate device failure, permanent parameter shifts and latent damage causing increased degradation rate. It has at least one of three components, localized heat generation, high current density and high electric field gradient; prolonged presence of currents of several amperes transfer energy to the device structure to cause damage. ESD in real circuits causes a damped wave with rapidly alternating polarity, the junctions stressed in the same manner; it has four basic mechanisms:
Catastrophic ESD failure modes include:
A parametric failure only shifts the device parameters and may manifest in stress testing; sometimes, the degree of damage can lower over time. Latent ESD failure modes occur in a delayed fashion and include:
Catastrophic failures require the highest discharge voltages, are the easiest to test for and are rarest to occur. Parametric failures occur at intermediate discharge voltages and occur more often, with latent failures the most common. For each parametric failure, there are 4–10 latent ones. Modern VLSI circuits are more ESD-sensitive, with smaller features, lower capacitance and higher voltage-to-charge ratio. Silicon deposition of the conductive layers makes them more conductive, reducing the ballast resistance that has a protective role.
The gate oxide of some MOSFETs can be damaged by 50 volts of potential, the gate isolated from the junction and potential accumulating on it causing extreme stress on the thin dielectric layer; stressed oxide can shatter and fail immediately. The gate oxide itself does not fail immediately but can be accelerated by stress induced leakage current, the oxide damage leading to a delayed failure after prolonged operation hours; on-chip capacitors using oxide or nitride dielectrics are also vulnerable. Smaller structures are more vulnerable because of their lower capacitance, meaning the same amount of charge carriers charges the capacitor to a higher voltage. All thin layers of dielectrics are vulnerable; hence, chips made by processes employing thicker oxide layers are less vulnerable.
Current-induced failures are more common in bipolar junction devices, where Schottky and PN junctions are predominant. The high power of the discharge, above 5 kilowatts for less than a microsecond, can melt and vaporise materials. Thin-film resistors may have their value altered by a discharge path forming across them, or having part of the thin film vaporized; this can be problematic in precision applications where such values are critical.
Newer CMOS output buffers using lightly doped silicide drains are more ESD sensitive; the N-channel driver usually suffers damage in the oxide layer or n+/p well junction. This is caused by current crowding during the snapback of the parasitic NPN transistor. In P/NMOS totem-pole structures, the NMOS transistor is almost always the one damaged. The structure of the junction influences its ESD sensitivity; corners and defects can lead to current crowding, reducing the damage threshold. Forward-biased junctions are less sensitive than reverse-biased ones because the Joule heat of forward-biased junctions is dissipated through a thicker layer of the material, as compared to the narrow depletion region in reverse-biased junction.
Passive element failures.
Resistors.
Resistors can fail open or short, alongside their value changing under environmental conditions and outside performance limits. Examples of resistor failures include:
Potentiometers and trimmers.
Potentiometers and trimmers are three-terminal electromechanical parts, containing a resistive path with an adjustable wiper contact. Along with the failure modes for normal resistors, mechanical wear on the wiper and the resistive layer, corrosion, surface contamination, and mechanical deformations may lead to intermittent path-wiper resistance changes, which are a problem with audio amplifiers. Many types are not perfectly sealed, with contaminants and moisture entering the part; an especially common contaminant is the solder flux. Mechanical deformations (like an impaired wiper-path contact) can occur by housing warpage during soldering or mechanical stress during mounting. Excess stress on leads can cause substrate cracking and open failure when the crack penetrates the resistive path.
Capacitors.
Capacitors are characterized by their capacitance, parasitic resistance in series and parallel, breakdown voltage and dissipation factor; both parasitic parameters are often frequency- and voltage-dependent. Structurally, capacitors consist of electrodes separated by a dielectric, connecting leads, and housing; deterioration of any of these may cause parameter shifts or failure. Shorted failures and leakage due to increase of parallel parasitic resistance are the most common failure modes of capacitors, followed by open failures. Some examples of capacitor failures include:
Electrolytic capacitors.
In addition to the problems listed above, electrolytic capacitors suffer from these failures:
Metal oxide varistors.
Metal oxide varistors typically have lower resistance as they heat up; if connected directly across a power bus, for protection against voltage spikes, a varistor with a lowered trigger voltage can slide into catastrophic thermal runaway and sometimes a small explosion or fire. To prevent this, the fault current is typically limited by a thermal fuse, circuit breaker, or other current limiting device.
MEMS failures.
Microelectromechanical systems suffer from various types of failures:
Recreating failure modes.
In order to reduce failures, a precise knowledge of bond strength quality measurement during product design and subsequent manufacture is of vital importance. The best place to start is with the failure mode. This is based on the assumption that there is a particular failure mode, or range of modes, that may occur within a product. It is therefore reasonable to assume that the bond test should replicate the mode, or modes of interest. However, exact replication is not always possible. The test load must be applied to some part of the sample and transferred through the sample to the bond. If this part of the sample is the only option and is weaker than the bond itself, the sample will fail before the bond.


Power integrity

Power integrity or PI is an analysis to check whether the desired voltage and current are met from source to destination. Today, power integrity plays a major role in the success and failure of new electronic products. There are several coupled aspects of PI: on the chip, in the chip package, on the circuit board, and in the system. Four main issues must be resolved to ensure power integrity at the printed circuit board level:
Power distribution network.
The current path from the power supply through the PCB and IC package to the die (consumer) is called the power distribution network. Its role is to transfer the power to the consumers with little DC voltage drop, and to allow little ripple induced by dynamic current at the consumer (switching current). The DC voltage drop occurs if there is too much resistance in the plane or power traces leading from the VRM (Voltage Regulator Module) to the consumer. This can be countered by raising the voltage on the VRM, or extending the "sense" point of the VRM to the consumer.
Dynamic current occurs when the consumer switches its transistors, typically triggered by a clock signal. This dynamic current can be considerably larger than the static current (internal leakage) of the consumer. This fast change in current consumption can pull the voltage of the rail down, or cause it to spike, creating a voltage ripple. This change in current happens much faster than the VRM can react. The switching current must therefore be handled by decoupling capacitors.
The noise or voltage ripple must be handled differently depending on the frequency of operation. The highest frequencies must be handled on-die. This noise is decoupled by parasitic coupling on the die, and capacitive coupling between metal layers. Frequencies above 50100MHz must be handled on the package. This is done by on-package capacitors. Frequencies below 100MHz are handled on the PCB by plane capacitance and using decoupling capacitors. Capacitors work on different frequencies depending on their type, capacitance and physical size. It is therefore necessary to utilize multiple capacitors of different sizes to ensure a low PDN impedance across the frequency range.
The physical size of the capacitors affect its parasitic inductance. The parasitic inductance creates impedance spikes at certain frequencies. Physically smaller capacitors are therefore better. The placement of the capacitors is of varying importance depending on its frequency of operation. The smallest value capacitors should be as close as possible to the consumer to minimize the AC current loop area. Larger capacitors in the microfarad range can be placed more or less anywhere.
Target impedance.
The target impedance is the impedance at which the ripple created by the dynamic current of the specific consumer is within the specified range. The target impedance is given by the following equation
In addition to the target impedance, it is important to know which frequencies it applies, and at which frequency the consumer package is responsible (this is specified in the datasheet of the specific consumer IC).
One usually use some form of simulation when designing the PDN to ensure that the PDN meets the target impedance. This can be done by SPICE simulation, chip vendor tools, capacitor vendor tools, or by tools embedded in the EDA software.


Bexel

SM Bexel Co, Ltd. (, formerly known as Bexel) is a South Korean chemical company specializing in battery manufacture. It is headquartered in Yangpyeong-dong Yeongdeungpo-gu, Seoul and Gongdan-dong, Gumi, Gyeongsangbuk-do, South Korea. Founded in 1978, it also manufactures other electronic products. Manufacturing is based in Gumi, Gyeongsangbuk-do.


Supply chain engineering

Supply chain engineering is the engineering discipline that concerns the planning, design, and operation of supply chains. Some of its main areas include logistics, production, and pricing. It involves various areas in mathematical modelling such as operations research, machine learning, and optimization, which are usually implemented using software.
Supply chain engineering draws heavily from, and overlaps with other engineering disciplines, such as industrial engineering, manufacturing engineering, systems engineering, information engineering, and software engineering. Although they have the same goals, supply chain engineering is focused on a mathematical model-based approach, whereas supply chain management is focused on a more traditional management and business-based one. Supply chain engineering can be considered to include supply chain optimization, although the latter could also be done using more qualitative management-based approaches, which is less of a focus in supply chain engineering.
Applications.
Supply chain engineering is applied to all parts of supply chains, including:
Techniques.
Supply chain engineering uses a wide variety of mathematical techniques such as:


Manoir Industries

Manoir Industries is a global metal processing company mainly focusing on high tech casting and forging components in petrochemical, nuclear, oil and gas, civil engineering, energy, defense, heavy weight trucks, tractors and aerospace markets. Manoir Industries employs 1,400 workers in 7 manufacturing locations in France, the United Kingdom, India and China.
History.
Manoir Industries was created in 1917 in the commune of Pîtres in northwestern France. It was built between the towns of Pîtres and Le Manoir, from the latter of which comes its trade name. Manoir has become the Manoir Industries group by successive acquisitions. From 1917 to 1995, Manoir Industries acquired forging plants including Bouzonville, and Manoir Custines then Saint-Brieuc's foundry dedicated to wear parts. In 1994, Manoir expanded to a worldwide presence with a joint-venture in China becoming Yantai Manoir in 2006. In 2008 Hi-Tech Fabrication, a welding company located in the United Kingdom, joined the group, and in 2010 Kartik Steels also became part of Manoir. Kartik, specializing in tube supports for petrochemical furnaces, is a foundry in Chennai, India.
On February 28, 2013, the Yantai Taihai Group, a Manoir Industries partner for 15 years and a leading private company in China for nuclear casting and forging components, became Manoir's newest shareholder and committed to a long-term partnership with Manoir by speeding-up investments and building-up its international position.
Manufacturing process.
Manoir Industries technologies and know-how cover steel casting (static and centrifugal casting), forging (close-die, extrusion, welding), and provide ‘ready-to-assemble’ gear grinding and cutting, machined, surface treated, painted, shotblasted, coated parts to its customers.
In forging or casting processes, small- and mid-size batches of various morphologies are manufactured in a large range of alloys and are undergo controls meeting customers quality requirements:
The Petrochemical and Nuclear BU with the Pîtres, Burton-on-Trent, Yantai and Chennai plants offer high technology components to withstand high temperatures. The Excellence center, based in Pîtres and historical innovator of high temperature alloys, guarantees the process and quality for Manoir's Petrochemical plants.
The Manoir Forging Solutions with the Bouzonville forging plant and Manoir Engrenages provide all the closed-die, extrusion, gear grinding and cutting, machining and control processes for parts operating under severe conditions (nuclear, defense, oil&gas, mine, civil engineering, transport (heavy weight trucks and railways components), tractors and aerospace...).
Innovation and customers service.
Manoir Industries develop high-temperature alloys which increase the life cycle of components and improve the existing solutions. Manoir AlloyServices enhance the performance of petrochemical facilities
Bouzonville’designer of forged components works with clients, from the design stage to the delivery of ready-to-assemble sets.


Stand-up pouch

A stand-up pouch or doypack is a type of flexible packaging that is able to stand erect on its bottom for display, storage, and convenience. It has characteristics of plastic bags, water bottles, and retort pouches. The bottom part of a stand-up pouch is gusseted to provide support for display or use.
Stand-up pouches are commonly used for food packaging. They can be aseptically filled or filled on normal packaging lines.
History.
Early work on stand-up pouches was conducted in France by Leon and Louis Doyen. Doyen was president of Thimonnier Company, which trademarked the name "Doypack" (from "DOY"en "PACK"aging").
Development of materials, design options, and equipment increased in the 1980s and 1990s. Development of the retort pouch was closely related. It is currently a very widely used package form.
Construction.
The flexible pouches are usually constructed of multi-layer materials: various plastic films, paper, foil, etc. Pouches are often printed with high-impact graphics or sometimes have attached labels. The materials must have specialized heat-seal properties to allow conversion into pouches.
The most common pouch has bottom gussets to form a "W" which opens to allow a flat bottom. Side gussets are also sometimes used. Several design options are available.
Inclusion of pour spouts and re-closable zip strips is common.
Equipment.
The packaging machinery involved typically forms the pouch from preprinted roll stock. The preformed pouches are shipped to a packager where they are filled and the top is sealed.
The alternative is an integral form-fill-seal machine, whether vertical or horizontal. The equipment forms the pouches, fills the pouches in-line, and seals them. With foods, drinks, or medical products, special sanitizing and wash-down requirements are critical.
The resulting equipment is sometimes complex and expensive. Packagers who do not have the volume to fill a machine to its capacity often use contract packagers.


Advanced planning and scheduling

Advanced planning and scheduling (APS, also known as advanced manufacturing) refers to a manufacturing management process by which raw materials and production capacity are optimally allocated to meet demand. APS is especially well-suited to environments where simpler planning methods cannot adequately address complex trade-offs between competing priorities. Production scheduling is intrinsically very difficult due to the (approximately) factorial dependence of the size of the solution space on the number of items/products to be manufactured.
Difficulty of production planning.
Traditional production planning and scheduling systems (such as manufacturing resource planning) use a stepwise procedure to allocate material and production capacity. This approach is simple but cumbersome, and does not readily adapt to changes in demand, resource capacity or material availability. Materials and capacity are planned separately, and many systems do not consider material or capacity constraints, leading to infeasible plans. However, attempts to change to the new system have not always been successful, which has called for the combination of management philosophy with manufacturing.
Unlike previous systems, APS simultaneously plans and schedules production based on available materials, labor and plant capacity.
APS has commonly been applied where one or more of the following conditions are present:
Advanced planning & scheduling software enables manufacturing scheduling and advanced scheduling optimization within these environments.


Balancing network

In a hybrid set, hybrid coil, or resistance hybrid, balancing network is a circuit used to match, "i.e.", to balance, the impedance of a uniform transmission line, (e.g., a twisted metallic pair, coaxial cable, etc.) over a selected range of frequencies. A balancing network is required to ensure isolation between the two ports of the four-wire side of the hybrid.
A balancing network can also be a device used between a balanced device or line and an unbalanced device or line for the purpose of transforming from balanced to unbalanced or from unbalanced to balanced.
Source: from Federal Standard 1037C and from MIL-STD-188


Dual in-line package

In microelectronics, a dual in-line package (DIP or DIL) is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. The dual-inline format was invented by Don Forbes, Rex Rice and Bryant Rogers at Fairchild R&D in 1964, when the restricted number of leads available on circular transistor-style packages became a limitation in the use of integrated circuits. Increasingly complex circuits required more signal and power supply leads (as observed in Rent's rule); eventually microprocessors and similar complex devices required more leads than could be put on a DIP package, leading to development of higher-density chip carriers. Furthermore, square and rectangular packages made it easier to route printed-circuit traces beneath the packages.
A DIP is usually referred to as a DIP"n", where "n" is the total number of pins. For example, a microcircuit package with two rows of seven vertical leads would be a DIP14. The photograph at the upper right shows three DIP14 ICs. Common packages have as few as three and as many as 64 leads. Many analog and digital integrated circuit types are available in DIP packages, as are arrays of transistors, switches, light emitting diodes, and resistors. DIP plugs for ribbon cables can be used with standard IC sockets.
DIP packages are usually made from an opaque molded epoxy plastic pressed around a tin-, silver-, or gold-plated lead frame that supports the device die and provides connection pins. Some types of IC are made in ceramic DIP packages, where high temperature or high reliability is required, or where the device has an optical window to the interior of the package. Most DIP packages are secured to a PCB by inserting the pins through holes in the board and soldering them in place. Where replacement of the parts is necessary, such as in test fixtures or where programmable devices must be removed for changes, a DIP socket is used. Some sockets include a zero insertion force (ZIF) mechanism.
Variations of the DIP package include those with only a single row of pins, e.g. a resistor array, possibly including a heat sink tab in place of the second row of pins, and types with four rows of pins, two rows, staggered, on each side of the package. DIP packages have been mostly displaced by surface-mount package types, which avoid the expense of drilling holes in a PCB and which allow higher density of interconnections.
Applications.
Types of devices.
DIPs are commonly used for integrated circuits (ICs). Other devices in DIP packages include resistor networks, DIP switches, LED segmented and bar graph displays, and electromechanical relays.
DIP connector plugs for ribbon cables are common in computers and other electronic equipment.
Dallas Semiconductor manufactured integrated DIP real-time clock (RTC) modules which contained an IC chip and a non-replaceable 10-year lithium battery.
DIP header blocks on to which discrete components could be soldered were used where groups of components needed to be easily removed, for configuration changes, optional features or calibration.
Uses.
The original dual-in-line package was invented by Bryant "Buck" Rogers in 1964 while working for Fairchild Semiconductor. The first devices had 14 pins and looked much like they do today. The rectangular shape allowed integrated circuits to be packaged more densely than previous round packages. The package was well-suited to automated assembly equipment; a PCB could be populated with scores or hundreds of ICs, then all the components on the circuit board could be soldered at one time on a wave soldering machine and passed on to automated testing machines, with very little human labor required. DIP packages were still large with respect to the integrated circuits within them. By the end of the 20th century, surface-mount packages allowed further reduction in the size and weight of systems. DIP chips are still popular for circuit prototyping on a breadboard because of how easily they can be inserted and used there.
DIPs were the mainstream of the microelectronics industry in the 1970s and 1980s. Their use has declined in the first decade of the 21st century due to the emerging new surface-mount technology (SMT) packages such as plastic leaded chip carrier (PLCC) and small-outline integrated circuit (SOIC), though DIPs continued in extensive use through the 1990s, and still continue to be used substantially as the year 2011 passes. Because some modern chips are available only in surface-mount package types, a number of companies sell various prototyping adapters to allow those surface-mount devices (SMD) to be used like DIP devices with through-hole breadboards and soldered prototyping boards (such as stripboard and perfboard). (SMT can pose quite a problem, at least an inconvenience, for prototyping in general; most of the characteristics of SMT that are advantages for mass production are difficulties for prototyping.)
For programmable devices like EPROMs and GALs, DIPs remained popular for many years due to their easy handling with external programming circuitry (i.e., the DIP devices could be simply plugged into a socket on the programming device.) However, with In-System Programming (ISP) technology now state of the art, this advantage of DIPs is rapidly losing importance as well.
Through the 1990s, devices with fewer than 20 leads were manufactured in a DIP format in addition to the newer formats. Since about 2000, newer devices are often unavailable in the DIP format.
Mounting.
DIPs can be mounted either by through-hole soldering or in sockets. Sockets allow easy replacement of a device and eliminates the risk of damage from overheating during soldering. Generally sockets were used for high-value or large ICs, which cost much more than the socket. Where devices would be frequently inserted and removed, such as in test equipment or EPROM programmers, a zero insertion force socket would be used.
DIPs are also used with breadboards, a temporary mounting arrangement for education, design development or device testing. Some hobbyists, for one-off construction or permanent prototyping, use point-to-point wiring with DIPs, and their appearance when physically inverted as part of this method inspires the informal term "dead bug style" for the method.
Construction.
The body (housing) of a DIP containing an IC chip is usually made from molded plastic or ceramic. The hermetic nature of a ceramic housing is preferred for extremely high reliability devices. However, the vast majority of DIPs are manufactured via a thermoset molding process in which an epoxy mold compound is heated and transferred under pressure to encapsulate the device. Typical cure cycles for the resins are less than 2 minutes and a single cycle may produce hundreds of devices.
The leads emerge from the longer sides of the package along the seam, parallel to the top and bottom planes of the package, and are bent downward approximately 90 degrees (or slightly less, leaving them angled slightly outward from the centerline of the package body). (The SOIC, the SMT package that most resembles a typical DIP, appears essentially the same, notwithstanding size scale, except that after being bent down the leads are bent upward again by an equal angle to become parallel with the bottom plane of the package.) In ceramic (CERDIP) packages, an epoxy or grout is used to hermetically seal the two halves together, providing an air and moisture tight seal to protect the IC die inside. Plastic DIP (PDIP) packages are usually sealed by fusing or cementing the plastic halves around the leads, but a high degree of hermeticity is not achieved because the plastic itself is usually somewhat porous to moisture and the process cannot ensure a good microscopic seal between the leads and the plastic at all points around the perimeter. However, contaminants are usually still kept out well enough that the device can operate reliably for decades with reasonable care in a controlled environment.
Inside the package, the lower half has the leads embedded, and at the center of the package is a rectangular space, chamber, or void into which the IC die is cemented. The leads of the package extend diagonally inside the package from their positions of emergence along the periphery to points along a rectangular perimeter surrounding the die, tapering as they go to become fine contacts at the die. Ultra-fine bond wires (barely visible to the naked human eye) are welded between these die periphery contacts and bond pads on the die itself, connecting one lead to each bond pad, and making the final connection between the microcircuits and the external DIP leads. The bond wires are not usually taut but loop upward slightly to allow slack for thermal expansion and contraction of the materials; if a single bond wire breaks or detaches, the entire IC may become useless. The top of the package covers all of this delicate assemblage without crushing the bond wires, protecting it from contamination by foreign materials.
Usually, a company logo, alphanumeric codes and sometimes words are printed on top of the package to identify its manufacturer and type, when it was made (usually as a year and a week number), sometimes where it was made, and other proprietary information (perhaps revision numbers, manufacturing plant codes, or stepping ID codes.)
The necessity of laying out all of the leads in a basically radial pattern in a single plane from the die perimeter to two rows on the periphery of the package is the main reason that DIP packages with higher lead counts must have wider spacing between the lead rows, and it effectively limits the number of leads which a practical DIP package may have. Even for a very small die with many bond pads (e.g. a chip with 15 inverters, requiring 32 leads), a wider DIP would still be required to accommodate the radiating leads internally. This is one of the reasons that four-sided and multiple rowed packages, such as PGAs, were introduced (around the early 1980s).
A large DIP package (such as the DIP64 used for the Motorola 68000 CPU) has long leads inside the package between pins and the die, making such a package unsuitable for high speed devices.
Some other types of DIP devices are built very differently. Most of these have molded plastic housings and straight leads or leads that extend directly out of the bottom of the package. For some, LED displays particularly, the housing is usually a hollow plastic box with the bottom/back open, filled (around the contained electronic components) with a hard translucent epoxy material from which the leads emerge. Others, such as DIP switches, are composed of two (or more) plastic housing parts snapped, welded, or glued together around a set of contacts and tiny mechanical parts, with the leads emerging through molded-in holes or notches in the plastic.
Variants.
Several DIP variants for ICs exist, mostly distinguished by packaging material:
EPROMs were sold in ceramic DIPs manufactured with a circular window of clear quartz over the chip die to allow the part to be erased by ultraviolet light. Often, the same chips were also sold in less expensive windowless PDIP or CERDIP packages as one-time programmable (OTP) versions. Windowed and windowless packages were also used for microcontrollers, and other devices, containing EPROM memory. Windowed CERDIP-packaged EPROMs were used for the BIOS ROM of many early IBM PC clones with an adhesive label covering the window to prevent inadvertent erasure through exposure to ambient light.
Molded plastic DIPs are much lower in cost than ceramic packages; one 1979 study showed that a plastic 14 pin DIP cost around US$0.063 and a ceramic package cost US$0.82.
Single in-line.
A single in-line package (SIP or SIL) has one row of connecting pins. It is not as popular as the DIP, but has been used for packaging RAM chips and multiple resistors with a common pin. As compared to DIPs with a typical maximum pin count of 64, SIPs have a typical maximum pin count of 24 with lower package costs.
One variant of the single in-line package uses part of the lead frame for a heat sink tab. This multi-leaded power package is useful for such applications as audio power amplifiers, for example.
Quad in-line.
The QIP, sometimes called a QIL package, has the same dimensions as a DIL package, 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 DIL). The QIL design increased the spacing between solder pads without increasing package size, for two reasons:
Lead count and spacing.
Commonly found DIP packages that conform to JEDEC standards use an inter-lead spacing (lead pitch) of (JEDEC MS-001BA). Row spacing varies depending on lead counts, with 0.3 in. (7.62 mm) (JEDEC MS-001) or 0.6 inch (15.24 mm) (JEDEC MS-011) the most common. Less common standardized row spacings include 0.4 inch (10.16 mm) (JEDEC MS-010) and 0.9 inch (22.86 mm), as well as a row spacing of 0.3 inch, 0.6 inch or 0.75 inch with a 0.07 inch (1.778 mm) lead pitch.
The former Soviet Union and Eastern bloc countries used similar packages, but with a metric pin-to-pin spacing of 2.5 mm rather than .
The number of leads is always even. For 0.3 inch spacing, typical lead counts are 8, 14, 16, 18, and 28; less common are 4, 6, 20, and 24 lead counts. To have an even number of leads some DIPs have unused not connected (NC) leads to the internal chip, or are duplicated, e.g. two ground pins. For 0.6 inch spacing, typical lead counts are 24, 28, 32, and 40; less common are 36, 42, 48, 52, and 64 lead counts. Some microprocessors, such as the Motorola 68000 and Zilog Z180, used lead counts as high as 64; this is typically the maximum number of leads for a DIP package.
Orientation and lead numbering.
As shown in the diagram, leads are numbered consecutively from Pin 1. When the identifying notch in the package is at the top, Pin 1 is the top left corner of the device. Sometimes Pin 1 is identified with an indent or paint dot mark.
For example, for a 14-lead DIP, with the notch at the top, the left leads are numbered from 1 to 7 (top to bottom) and the right row of leads are numbered 8 to 14 (bottom to top).
Some DIP devices, such as segmented LED displays, relays, or those that replace leads with a heat sink fin, skip some leads; the remaining leads are numbered as if all positions had leads.
In addition to providing for human visual identification of the orientation of the package, the notch allows automated chip-insertion machinery to confirm correct orientation of the chip by mechanical sensing.
Descendants.
The SOIC (Small Outline IC), a surface-mount package which is currently very popular, particularly in consumer electronics and personal computers, is essentially a shrunk version of the standard IC PDIP, the fundamental difference which makes it an SMT device being a second bend in the leads to flatten them parallel to the bottom plane of the plastic housing. The SOJ (Small Outline J-lead) and other SMT packages with "SOP" (for "Small Outline Package") in their names can be considered further relatives of the DIP, their original ancestor. SOIC packages tend to have half the pitch of DIP, and SOP are half that, a fourth of DIP. (0.1"/2.54 mm, 0.05"/1.27 mm, and 0.025"/0.635 mm, respectively)
Pin grid array (PGA) packages may be considered to have evolved from the DIP. PGAs with the same pin centers as most DIPs were popular for microprocessors from the early to mid-1980s through the 1990s. Owners of personal computers containing Intel 80286 through P5 Pentium processors may be most familiar with these PGA packages, which were often inserted into ZIF sockets on motherboards. The similarity is such that a PGA socket may be physically compatible with some DIP devices, though the converse is rarely true.


Insertion loss

In telecommunications, insertion loss is the loss of signal power resulting from the insertion of a device in a transmission line or optical fiber and is usually expressed in decibels (dB).
If the power transmitted to the load before insertion is "P"T and the power received by the load after insertion is "P"R, then the insertion loss in decibels is given by,
Electronic filters.
Insertion loss is a figure of merit for an electronic filter and this data is generally specified with a filter. Insertion loss is defined as a ratio of the signal level in a test configuration without the filter installed (formula_2) to the signal level with the filter installed (formula_3). This ratio is described in decibels by the following equation:
For passive filters, formula_3 will be smaller than formula_2. In this case, the insertion loss is positive and measures how much smaller the signal is after adding the filter.
Link with scattering parameters.
In case the two measurement ports use the same reference impedance, the insertion loss (formula_7) is defined as:
Here formula_9 is one of the scattering parameters. Insertion loss is the extra loss produced by the introduction of the DUT between the 2 reference planes of the measurement. The extra loss can be introduced by intrinsic loss in the DUT and/or mismatch. In case of extra loss the insertion loss is defined to be positive.


Adams (1903 automobile)

Adams was an automobile introduced manufactured by the Adams Manufacturing Co. Ltd. from 1903 to 1906. It was developed by H. Adams, of Tunbridge Wells, Kent, England, who offered a conversion set that converted horse-drawn carriages into motorized automobiles. The engine was mounted on a swivelling fore-carriage, and steering was achieved through wheel and vertical column. In 1905, Adams produced a small 2-cylinder car sold under the name 'One of the Best'.


Brushed metal

Brushed or dull polished metal is metal with a unidirectional satin finish. It is produced by polishing the metal with a 120–180 grit belt or wheel then softening with an 80–120 grit greaseless compound or a medium non-woven abrasive belt or pad.
Commonly brushed metals include stainless steel, aluminium and nickel. Brushed finishes are popular in both small appliances and whiteware, and feature in architecture and automotive design. The Gateway Arch and DMC DeLorean are both clad in brushed stainless steel. The intensity of the brushed finish is specified as a surface roughness and is typically 0.5–1.5 micrometres Ra.
Characteristics.
Brushing gives metal a distinctive look, as it retains some but not all of its metallic lustre and is given a pattern of very fine lines parallel to the brushing direction. For this reason, it is commonly used for decorative items like jewelry and watches.
A brushed finish is susceptible to damage. Brushed finishes also typically have a detrimental effect on corrosion resistance. In particular the brushed texture limits the ability of fluid to bead on the material surface. In the case of stainless steel the grooves of the finish can accumulate chloride ions which break down the chromium oxide passivation layer, enabling rusting to occur.


Cold working

In metallurgy, cold forming or cold working is any metalworking process in which metal is shaped below its recrystallization temperature, usually at the ambient temperature. Such processes are contrasted with hot working techniques like hot rolling, forging, welding, etc. The same or similar terms are used in glassmaking for the equivalents; for example cut glass is made by "cold work", cutting or grinding a formed object.
Cold forming techniques are usually classified into four major groups: squeezing, bending, drawing, and shearing. They generally have the advantage of being simpler to carry out than hot working techniques.
Unlike hot working, cold working causes the crystal grains and inclusions to distort following the flow of the metal; which may cause work hardening and anisotropic material properties. Work hardening makes the metal harder, stiffer, and stronger, but less plastic, and may cause cracks of the piece.
The possible uses of cold forming are extremely varied, including large flat sheets, complex folded shapes, metal tubes, screw heads and threads, riveted joints, and much more.
Processes.
The following is a list of cold forming processes:
Advantages.
Advantages of cold working over hot working include:
Depending on the material and extent of deformation, the increase in strength due to work hardening may be comparable to that of heat treating. Therefore, it is sometimes more economical to cold work a less costly and weaker metal than to hot work a more expensive metal that can be heat treated, especially if precision or a fine surface finish is required as well.
The cold working process also reduces waste as compared to machining, or even eliminates with near net shape methods. The material savings becomes even more significant at larger volumes, and even more so when using expensive materials, such as copper, nickel, gold, tantalum, and palladium. The saving on raw material as a result of cold forming can be very significant, as is saving machining time. Production cycle times when cold working are very short. On multi-station machinery, production cycle times are even less. This can be very advantageous for large production runs.
Disadvantages.
Some disadvantages and problems of cold working are:
The need for heavier equipment and harder tools may make cold working suitable only for large volume manufacturing industry.
The loss of plasticity due to work hardening may require intermediate annealings, and a final annealing to relieve residual stress and give the desired properties to the manufactured object. These extra steps would negate some of the economic advantages of cold forming over hot forming.
Cold worked items suffer from a phenomenon known as "springback", or "elastic springback". After the deforming force is removed from the workpiece, the workpiece springs back slightly. The amount a material springs back is equal to the yield strain (the strain at the yield point) for the material.
Special precautions may be needed to maintain the general shape of the workpiece during cold working, such as shot peening and equal channel angular extrusion.