Pay on production

Pay on production (PoP) is a special build-operate-transfer (BOT) model, where payment is made to a supplier by the original equipment manufacturer (OEM) per piece produced on the supplier's own equipment by the OEM's employees.
Description.
Most build-operate-transfer systems work in a way that the final manufacturer (OEM) doesn't invest in the production equipment for parts or components but instead procures these parts from a supplier who organises production on his equipment. An example from vehicle manufacturing might be the assembly of wheels and tyres. The OEM might decide not to invest in a wheel assembly line but instead obtain from a supplier or logistics service provider delivery of these items just in sequence as these are needed at the OEM's assembly line: sometimes five with steel rim followed by four with light-alloy rim and a compact spare tire and so on. This is a longstanding and common methodology where the production and supply of many items and services are outsourced to other providers, typically to obtain better cost, quality and delivery performance than can be achieved in house, and also enable the OEM to better focus on core activities.
With PoP one important thing is different. The very equipment on which the OEM produces or assembles the final product, in the OEM factory, is supplied by, but still remains owned by, and is also maintained by, the equipment supplier. But it is still the OEM's personnel who assemble the products on the equipment and facilities. The external equipment supplier is then paid a fixed price for every product item which is assembled or produced on their equipment. The general idea of PoP is similar to using a rented car. The car is always owned and maintained by the car rental company but used or driven by the customer. The customer pays the car rental company for using the car, e.g. per every driven kilometre. However, in the assembly line case the contract is not just for a few days, rather both partners plan to keep the agreement for as long as the product is produced on the equipment, though it can be terminated before this. It means PoP is not therefore so much a production system, more of a financial model.
This concept was established by the German Ford Motor Company in Cologne for the Fiesta assembly line in 2002, and was soon recognised as the most productive in the world measured by working hours used to assemble a car. The new Fiesta was started on this line at 2008 and the high productivity remained (i.e. til 2010). This is despite the Cologne factory, because the buildings are 90 years old, is laid out in such a way that many new production developments just can't be introduced. For example, component suppliers can't deliver straight to the assembly line nor is there room for more flexible U shaped assembly areas. Parts have to be delivered to a separate ‘supermarket’ type warehouse where kits of required parts are boxed and made up for use on the lines. For the Cologne factory the main assembly lines and some of the cells, for example where engines are fitted to the body, are owned and maintained by several equipment suppliers.
History and Background.
Within the beginning of the 21st century, the Ford Motor Company's goal was to focus and concentrate on designing new cars. There were no surplus funds available for investment in the modern manufacturing equipment needed at the Cologne plant. Indeed, for the equipment suppliers their participation in PoP was the only option available.
Most of the costs incurred by the OEM in PoP are variable costs such as labour and materials, though there is also in this case an additional variable cost for the equipment for every car produced. The fixed cost of the production equipment is borne the external equipment suppliers. For the OEM it means that PoP allows it to run its own production, but without incurring the high fixed capital cost of the equipment, and of course this cost is absent from any US GAAP balance sheet, not even included as a footnote, nor is it factor in assessment by financial rating agencies. Also with PoP much of the OEM's entrepreneurial risks are passed to the equipment supplier.
For the equipment supplier bearing the equipment capital cost can often be a financial problem, because, where these are SME companies, they are not always able to easily obtain sufficient investment capital, nor are they able to receive money from global financial markets. However the assembly lines and cells can't be sold or built without the supplier's permission and, most importantly, the equipment supplier, who has continuous contact with the lines and cells, is much closer to its customers so enabling ongoing CIP (continuous improvement process) both in the equipment maintenance and collaborative future line design improvements. CIP improvements in production stay with the OEM
Because the use of the practice by Ford in Cologne was so successful its use and adoption was tried at other Ford assembly plants. Perhaps not unsurprisingly, Ford has not been successful in their attempts to expand this Ford Cologne-based system elsewhere.


Quick response manufacturing

Quick response manufacturing (QRM) is an approach to manufacturing which emphasizes the beneficial effect of reducing internal and external lead times.
Description.
Shorter lead times improve quality, reduce cost and eliminate non-value-added waste within the organization while simultaneously increasing the organization's competitiveness and market share by serving customers better and faster.
The time-based framework of QRM accommodates strategic variability such as offering custom-engineered products while eliminating dysfunctional variability such as rework and changing due dates. For this reason, companies making products in low or varying volumes have used QRM as an alternative or to complement other strategies such as Lean Manufacturing, Total quality management, Six Sigma or Kaizen. However, the benefits of QRM are still mooted and contested by experts around. Many opposers of QRM criticize its approach being very "marketing-style" rather than academic or statistical.
History.
Background.
QRM is rooted in the concept of Time-based competition (TBC) pioneered by Japanese enterprises in the 1980s and first formulated by George Stalk Jr. in his 1988 article entitled "Time – The Next Source of Competitive Advantage". Time-based competition is a broad-based competitive strategy emphasizing time as the major factor for achieving and maintaining a sustainable competitive advantage. It seeks to compress the time required to propose, develop, manufacture, market and deliver products.
QRM advocates a companywide focus on short lead times that include quick response to demand for existing products as well as new product and design changes. This combination has led to the implementation of QRM in many high-mix, low-volume companies.
Some argue that Quick Response Manufacturing differs from Quick Response (QR) methods used in the apparel industry and the fast fashion market. QRM is a companywide management strategy applicable to a wide variety of businesses, whereas QR primarily stands for a specific business model in a particular industry. However, the important difference to note is that QR was a competitive industry initiative introduced in the US Textile Industry in 1984 as a means of improving efficiencies in manufacturing and supply chain processes and as such was one of the earliest pioneers of putting into practice time-based competition prior to Stalk's seminal article. Thus QR crossed the traditional boundaries of organization and was not limited to a single organizational efficiency improvement such as that advocated by proponents of QRM. In this respect the Textile Industry initiative was innovative and visionary in its application of QR techniques across the supply chain.
Development.
The concept of Quick Response Manufacturing (QRM) was first developed in the late 1980s by Rajan Suri, at the time professor of Industrial and Systems Engineering at the University of Wisconsin-Madison. Combining growing academic research in Time-based Competition (TBC) with his own observations from various lead time reduction projects, Suri conceived QRM as a concept espousing a relentless emphasis on lead time reduction that has a long-term impact on every aspect of the company.
In 1993, Suri, along with a few U.S. Midwest companies and academic colleagues at the University of Wisconsin-Madison, launched the Center for Quick Response Manufacturing, a consortium dedicated to the development and implementation of QRM principles in an industry setting. Proposed by Suri, the newly coined term "Quick Response Manufacturing" (QRM) signifies the new strategy.
QRM extends basic principles of time-based competition while including these new aspects:
Suri's continued research into QRM through industry projects along with enthusiastic responses to various articles on lead time reduction issues led him to develop a comprehensive theory on implementing speed in a manufacturing company, covering all areas in the enterprise. He formulated his theory in the book "Quick Response Manufacturing: A Companywide Approach to Reducing Lead Times (1998)", providing a framework for the implementation of QRM in manufacturing companies.
QRM Strategies and Tools.
Lead time as a management strategy.
Traditionally, U.S. manufacturing firms have focused on scale and cost management strategies based on the division of labor practices formalized by Frederick Winslow Taylor and pioneered by Henry Ford.
From the time-based perspective of QRM, the high degree of labor specialization and hierarchical department structures at purely cost-based organizations have these negative effects on lead times:
All these factors contribute to long lead times, ultimately resulting in waste throughout the enterprise such as excessive forecasting, planning, scheduling, expediting, work in progress (WIP), finished goods costs and obsolescence. These increase the overall costs and lower the organization's competitiveness.
QRM suggests that an enterprisewide focus on reducing lead times will result in improvements in both quality and cost. Eliminating the time-consuming – and often self-reinforcing – practices described above can lead to large cost savings while improving product quality and customer responsiveness. Hence, on a management level, QRM advocates a mindset change from cost-based to time-based thinking, making short lead times the yardstick for organizational success.
Manufacturing Critical-path Time (MCT).
QRM's strong focus on lead time reduction requires a comprehensive definition of lead time. To accomplish this, QRM introduces Manufacturing Critical-path Time (MCT). It is based on the standard critical path method; defined as the typical amount of calendar time from when a customer creates an order, until the first piece of that order is delivered to the customer.
A metric designed to calculate waste and highlight opportunities for improvement, MCT gives an estimate of the time it takes to fulfill an order, quantifying the longest critical-path duration of order-fulfillment activities.
Organizational structure.
QRM requires four fundamental structural changes to transform a company organized around cost-based management strategies to a time-based focus:
QRM Cell.
The main building block of the QRM organization is the QRM cell. Extending the concept of cellular manufacturing, QRM cells are designed around a Focused Target Market Segment (FTMS) – a segment of the market in which shorter product lead times provide the company with maximum benefits. Resources in a cell are dedicated (only to be used for jobs in the cell), collocated (located in close proximity to each other) and multifunctional (cover different functions). QRM cells complete a sequence of operations ensuring that jobs leave the cell completed and do not need to return.
The work organization in QRM cells is based on team ownership. Provided with a job and a completion deadline, teams can decide independently on how to complete the job. To ensure quick response to high-variety demand, workers in QRM cells need to go through cross training.
The main performance measure for a QRM cell is lead time as defined by MCT. To measure MCT reduction, managers can use the QRM number, a metric designed to show management lead time trends for cells.
System Dynamics.
In QRM, the product-focused cell structure has to be complemented by a thorough understanding of system dynamics in order to make better decisions to reduce lead times. Based on principles of system dynamics, QRM identifies high utilization of machines and labor as well as running large batch sizes as major obstacles to lead time reduction.
Create spare capacity.
Many cost-based organizations aim for machines and labor to be utilized at close to 100% of capacity. QRM criticizes this approach as counterproductive to lead time reduction based on queuing theory, which shows that high utilization increases waiting times for products. In order to be able to handle high variability in demand and products, QRM advises companies to operate at 80 percent capacity on critical resources.
Optimize batch sizes.
Common efficiency measures encourage production of parts in large batch sizes. From the QRM perspective, large batch sizes lead to long waiting times, high WIP and inventory, and ultimately long lead times. Long lead times in turn result in multiple forms of waste and increased cost as described above. Thus, QRM encourages enterprise to strive towards batch sizes that minimize lead times.
Enterprisewide Application.
QRM emphasizes time-based thinking throughout the organization, creating a unified management strategy for the entire enterprise. Extending beyond traditional efforts to optimize shop floor operations, QRM applies time-based management principles to all other parts of the organization.
Office Operations.
QRM identifies office operations such as quoting, engineering, scheduling and order processing as major contributors to lead times. To achieve short lead times in the office environment, QRM suggests implementing several changes according to the time-based approach described above.
The main requirement for reorganizing office operations in QRM is the formation of a Quick Response Office Cell (Q-ROC) around a Focus Target Market Segment (FTMS). In their focus on closed-loop, collocated, multifunctional, cross-trained teams, Q-ROCs are similar to QRM Cells. Q-ROCs, like QRM cells on the shop floor, break down functional departments and can complete jobs through multiple functional steps.
Material Planning.
QRM criticizes commonly used material planning and scheduling systems such as Material Requirements Planning (MRP), Manufacturing resource planning (MRP II), and Enterprise resource planning (ERP) for not incorporating system dynamics in their analysis and not accounting for the cost of long lead times.
QRM recommends simplifying existing MRP systems to a Higher Level MRP (HL/MRP) concerned with high-level planning and coordination of material and not with detailed scheduling of operations.
Production Control.
To coordinate and control flow within the QRM structure of cells and HL/MRP, QRM utilizes POLCA (Paired-cell Overlapping Loops of Cards with Authorization). POLCA is a card-based shop floor control system, designed as the QRM alternative to Kanban.
POLCA differs from commonly used Kanban systems in the type of signal it sends to move jobs/material through the shop floor. POLCA constitutes a capacity signal, showing that a cell is ready to work on a new job, whereas Kanban systems rely on inventory signals designed to replenish a certain quantity of parts. For this reason, POLCA works well for low-volume and/or custom products. The first QRM shop floor control system was developed by PROPOS software. PROPOS software was also the first to develop a digital version of the POLCA card system. In March 2018 Rajan Suri published The Practitioner's Guide to POLCA: The Production Control System for High-Mix, Low-Volume and Custom Products] in which Suri describes a practical approach to POLCA to maximize production efficiency, reduce WIP (Work in Process) and prevent bottlenecks from forming. Suri also describes the use of PROPOS QRM software and digital POLCA, illustrated by a case at BOSCH Scharnieren. This Dutch manufacturer produces custom metal hinges and managed to greatly reduce lead times and optimize the production flow in their job shop using QRM and POLCA principles.
Supply Chain.
QRM encourages companies to work with suppliers to reduce their MCT. Long supplier lead times can incur "hidden" costs such as high inventory, freight cost for rush shipments, unplanned engineering changes creating obsolete inventory, and reduced flexibility to respond to demand changes. QRM recommends that MCT be included as a significant factor in sourcing decisions.
New Product Introduction.
QRM highlights strategic advantages of rapid New Product Introduction (NPI). Applying the MCT metric to the NPI process provides valuable information on the current NPI performance. Based on these findings, QRM encourages managers to rethink cost-based decisions in terms of their impact on the NPI MCT. For example, cost-based purchasing policies can result in long purchasing times for prototype materials, in turn delaying the NPI.
Implementation.
QRM theory recommends following four common steps when implementing QRM:
Creating a QRM mindset.
QRM implementation requires company personnel to embrace the strategy's time-based principles. In a first step, a team of management and employees trained in QRM principles should compile a list of wastes due to long MCT, creating awareness for the negative impact of long lead times on operations.
If the company decides to take action, QRM theory recommends the creation of an organizational framework for the implementation effort. In this framework, a high-level QRM Steering Committee oversees all QRM efforts, while a QRM Champion – an experienced employee with sound QRM training – is charged with driving and overseeing projects on a day-to-day basis.
With this structure in place, the Steering Committee can pick a set of products as the target for the first QRM project.
Changing of organizational structure.
Following the general direction of the Steering Committee, a cross-functional planning team starts studying the project, including a detailed analysis of the MCT, product volumes, strategic needs and other factors. This analysis leads to the definition of the FTMS for the QRM project. Using QRM principles, the planning team designs a QRM cell for the FTMS.
With approval from management, an implementation team consisting of the people in the new cell and members of the planning team can start training activities, cross-training of operators and – if needed – relocation of equipment to launch the cell. After cell launching, the implementation team continues support for the new cell and measures MCT to monitor lead time changes.
Inclusion of system dynamics.
During both design of the cell and its operation, the implementation team should reexamine policies on utilization to properly plan the loading of the cells and to maintain spare capacity.
Furthermore, cells teams should be encouraged to engage in a program of batch size reduction.
Enterprisewide expansion of QRM.
After completing the initial project, the company needs to evaluate the results of these QRM efforts and publicize successes throughout the organization. Following the same pattern as described above, the company should identify additional FTMSs for other QRM projects and start the implementation process. As more cells are formed, restructuring of the MRP system and implementation of POLCA may become necessary.
To maximize benefits of a time-based management strategy, QRM projects should span across office operations, the shop floor and supply chain.
Practice.
Quick Response Manufacturing is used by a variety of companies from different sectors worldwide. As an enterprisewide strategy, QRM has found applications in all areas of the company from shop floor to office operations to supply chain and beyond. In the apparel industry, QRM has also become closely intertwined with the concepts of Fast fashion (Sweatshop) and Fast Fit, both of which are intended to reduce the timeframes typically associated with bringing catwalk style to the high street.
Many companies use QRM to address lead time issues in some parts of their organization or as an addition to existing continuous improvement efforts such as Lean, Six Sigma or others.
Another group of companies including Alexandria Extrusion, Omnipress, RenewAire and Phoenix Products have transformed their entire operation according to QRM principles making full use of QRM's enterprisewide reach.
In a 2008 article in Barron's magazine profiling the five companies most successful at boosting their sales and cash flow from among the 500 largest (by sales) publicly traded companies in the U.S. and Canada, Merrill Miller, chairman and CEO of National Oilwell Varco mentions improved manufacturing efficiencies based on QRM as a large part of NOV's growth.
In recent years, QRM principles have also found applications in the healthcare and pharmaceutical sector.
Center for Quick Response Manufacturing.
Founded in 1993 by Rajan Suri, along with a few U.S. Midwest companies and academic colleagues at the University of Wisconsin-Madison, the Center for Quick Response Manufacturing has been a driving force in the development and implementation of QRM.
Organized as a public-private consortium including faculty, students and company members, the Center has assisted more than 220 companies in applying QRM principles over the past 20 years.
The Center provides general information on QRM and hosts a variety of training events each year. Companies interested in implementing QRM can become members of the Center and take part in improvement projects conducted in cooperation with engineering students and university faculty.
Following the public-private partnership model, a new QRM Center at HAN University of Applied Sciences in Arnhem, Netherlands (founded 2010) is helping European companies implement QRM strategies.
Book.
T.C.E. Cheng, T.M. Choi (Eds.). Innovative Quick Response Programs in Logistics and Supply Chain Management, Springer, International Handbooks on Information Systems, 2010.


Backshop

A backshop or back-shop is a specialized store or workshop found in service industries, such as locomotive and aircraft repair. Most repairs are carried out in small workshops, except where an industrial service is needed.
In the military, backshops repair parts are known as shop-replaceable units (SRUs). These are commonly-stocked subassemblies of a larger system, such as circuit cards components of a line-replaceable unit (LRU), designed to be repaired at the field level. Repair at this level is known as field-level maintenance or intermediate-level (I-level) maintenance.
Calibration and repair of United States Air Force test equipment is conducted at shops known as precision measurement equipment laboratories.


TL.37

The TL.37 was an Italian military artillery tractor of World War II. It was manufactured by SPA ("Società Piemontese Automobili"), an Italian car maker that was a subsidiary of Fiat.
Development and history.
The tractor was chosen for the Royal Italian Army in 1938 as the result of a design competition between SPA and "Breda Meccanica Bresciana" for a light artillery tractor. It was subsequently used during World War 2 by all the Italian forces and was bought by Hungary. After the Italian Armistice in 1943, it continued to be used by German forces. Post–war, it was in service until 1948 with the Italian Navy.
The vehicle was notable for having four-wheel steering, that enabled it to have a turning circle. It was able to pull artillery pieces of 75mm and 100mm at a speed of on road, carrying five gun–crew in addition to the driver and of artillery ammunition. It was also able to climb a 40-degree slope.
A self-propelled gun variant was also built, with a Cannone da 75/27 modello 11 fitted at the rear. The TL.37 was also the basis for a general–purpose truck, the Fiat–SPA AS.37, and two armoured cars the Fiat–SPA S37 ("Fiat-SPA Autoprotetto S37") and the Fiat-SPA AS43.


Pettibone (company)

Pettibone, founded as Pettibone Mulliken, is a manufacturer of material handling equipment based in Baraga, Michigan. The company started doing business in 1881, and manufactures various cranes and other material handling vehicles, many designed specifically for railroad use.
History.
Pettibone Mulliken was founded in 1881 in Chicago, Illinois with Alfred H. Mulliken as president. Initially, the company's biggest product was railroad track and switch equipment.
By 1929, the company's manufacturing facilities in Chicago occupied 32 acres.
While primarily a manufacturer of cranes and other material handling equipment, the company received a $3,817,844 contract for artillery material from the United States Department of War in 1940, on the eve of U.S. entry into World War II. During the war, the company continued to manufacture artillery for the United States Armed Forces.
Pettibone today.
Today, the company is known simply as Pettibone. It primarily manufactures cranes and other material handling equipment, some of which is still sold specifically for the rail industry.
Pettibone is most known for its cranes, manufactured under the Speed Swing line. Pettibone cranes are used by railroads for a variety of applications, including lifting rails and moving ties.


Surface feet per minute

Surface feet per minute (SFPM or SFM) is the combination of a physical quantity ("surface speed") and an imperial and American customary unit ("feet per minute" or "FPM"). It is defined as the number of linear feet that a location on a rotating component travels in one minute. Its most common use is in the measurement of cutting speed (surface speed) in machining. It is a unit of velocity that describes how fast the cutting edge of the cutting tool travels. It correlates directly to the machinability of the workpiece material and the hardness of the cutting tool material. It relates to spindle speed via variables such as cutter diameter (for rotating cutters) or workpiece diameter (for lathe work).
SFM is a combination of "diameter" and the "velocity" (RPM) of the material measured in feet-per-minute as the spindle of a milling machine or lathe. 1 SFM equals 0.00508 m/s (meter per second, the SI unit of speed). The faster the spindle turns, and/or the larger the diameter, the higher the SFM. The goal is to tool a job to run the SFM as high as possible to increase hourly part production. However some materials will run better at specific SFMs. When the SFM is known for a specific material ("ex 303 annealed stainless steel = 120 SFM for high speed steel tooling"), a formula can be used to determine spindle speed for live tools or spindle speeds for turning materials.
In a milling machine, the "tool" diameter is used instead of the "stock" diameter in the following formulas when the tool is revolving and the stock is stationary.
Spindle speed can be calculated using the following equation:
SFM can be calculated using the following equation:


Columbia Manufacturing Inc.

Columbia Manufacturing Inc. is a company located in Westfield, Massachusetts that manufactures chairs, desks, and other materials. In the education industry, it is best known for making the desk chair Model 114, which is used across the United States. Founded in 1877, it was once owned by Pope Manufacturing Company and was the brand that manufactured bicycles for the company. After Pope filed for bankruptcy in 1915, Columbia continued on to manufacture bicycles in Westfield. As of the 2010s, Columbia-branded bicycles are marketed by Columbia Bicycles, a subsidiary of Ballard Pacific.


DSP coupling

A "DSP coupling" is a self-sealing symmetrical coupling which is secured by inter-connecting two couplings together.
It is closed by turning the locking ring on the triangular part of the opposed DSP coupling.
Extra closure can be applied by locking the connection with couplings wrench.
The DSP coupling locking principle is similar to that of the guillemin coupling.
However, there are differences to the preformed serration on the locking ring and the design of the lugs.
The locking ring of DSP couplings can be turned up to 45°.
DSP coupling are used as fire-fighting couplings. They are typical in for e.g. France and Belgium.
DSP couplings are symmetrical.
DSP comes in different sizes. (e.g. DN40 DN65 DN100).
Typical materials for the coupling are aluminum, brass and bronze.
For the Origin or meaning of "DSP" there is only speculation.


Amada Miyachi America

AMADA WELD TECH, a subsidiary of AMADA WELD TECH CO., LTD, designs and manufactures equipment and systems for resistance welding, laser welding, laser marking, laser cutting, laser micro machining, hermetic sealing, micro tig welding, and hot bar reflow soldering and bonding. Established in 1948, AMADA WELD TECH is headquartered in Monrovia, California, US. The company's equipment is used in numerous industries, chief among which are medical, aerospace, automotive, batteries, and electronic components.
AMADA WELD TECH has approximately 200 employees, with 7 sales and manufacturing offices serving about 12,000 customers worldwide. More than 80,000 items are manufactured annually. The company is certified to , China Compulsory Certificate (CCC), European Conformity (CE), and Canadian Standards Association (CSA) quality certifications.
AMADA WELD TECH CO., LTD..
AMADA WELD TECH's parent company, AMADA WELD TECH CO., LTD., was founded in 1972 to manufacture and market semiconductor-related measuring instruments and welding control equipment in response to the demand for quality control in the automobile, television, and electronics industries. The company incorporated microprocessors and other electronic devices into its resistance welders to enable high quality precision joining and monitoring and analysis. Its Weld Checkers™ are used worldwide for weld monitoring.
In 1984, the company developed a neodymium-doped yttrium aluminum garnet  laser welder that allowed for more precise and micro welding, and this product line became a central component of the company's business, along with resistance welding. In 2006, the company developed the first Yb: fiber laser welder in Japan.
AMADA WELD TECH CO., LTD. has more than 600 employees (consolidated), in 10 sales offices and 2 factories in Japan, and 7 subsidiary companies (AMADA WELD TECH Inc., AMADA WELD TECH Gmbh, AMADA WELD TECH Korea Co., Ltd., AMADA WELD TECH Shanghai Co., Ltd., Amada (Thailand) Co., Ltd., AMADA WELD TECH India Pvt., Ltd., AMADA WELD TECH Taiwan CO., Ltd., and Amada Vietnam Co., Ltd. and 4 factories overseas (China, USA, Germany, Thailand). Annual revenue is ¥20 billion.
AMADA WELD TECH is an AMADA Group Company. It is headquartered in Isehara, Kanagawa, Japan and develops, manufactures, sells, and services products and systems for metal sheet processing, metal cutting, pressing, and machine tooling. The company was established in 1946 and is listed on the Tokyo Stock Exchange (6113:Tokyo). It has 60 subsidiaries (17 in Japan and 43 overseas) and more than 7000 employees worldwide. Annual revenue exceeds ¥200 billion.
Products.
AMADA WELD TECH specializes in the design and manufacture of welding, marking, cutting and bonding equipment, as well as automated systems. Major products include:
Applications.
AMADA WELD TECH currently offers seven different technologies, which the company combines to create end-to-end assembly joining solutions to facilitate reliable and repeatable welding. A few of the key application areas include:
Patents.
AMADA WELD TECH has been awarded numerous patents for its resistance and laser welding inventions, over the period 1971 through the present, including the following:


Laser rapid manufacturing

Laser Rapid Manufacturing (LRM) is one of the advanced additive manufacturing processes that is capable of fabricating engineering components directly from a solid model.
Technique.
In this technique, a solid model of the component to be fabricated is made either by 3D imaging system or by designer using computer-aided design (CAD) software or by math data as an output of numerical analysis. Thus obtained model is sliced into thin layers along the vertical axis. The thin layers are converted into corresponding numerical controlled (NC) code and are sent to LRM station in suitable format (e.g. G&M code). LRM station employs a laser beam as a heat source to melt a thin layer on the surface of the substrate/deposited material and fed material to deposit a new layer as per shape and dimensions defined in NC code. A number of such layers deposited one over another and it results in three-dimensional (3D) components directly from the solid model.
Benefits.
LRM eliminates many manufacturing steps such as materials-machine planning, man-machine interaction, intermittent quality checks, assembly and related human errors etc. Therefore, LRM offers many advantages over conventional subtractive techniques, such as reduced production time, better process control and capability to form functionally graded parts. It is also an attractive candidate for refurbishing applications because of low heat input, limited dilution with minimal distortion and capability of adding finer near-net shaped features to the components.
Similar techniques.
Manufacturing techniques, similar to LRM, are being developed with different names at various laboratories, such as Laser Engineered Net Shaping (LENSTM) at Sandia National Laboratories (USA), Freeform Laser Consolidation at National Research Council (Canada), Selective Laser Powder Remelting (SLPR) at Fraunhofer Society (Germany), Selective Laser Cladding (SLC) at the University of Liverpool (UK), Shape deposition Manufacturing (SDM) at Stanford University (USA), Direct Metal Laser Sintering (DMLS) at Electrolux Rapid Development (Finland), Direct Metal Deposition at the University of Michigan, Automated Laser Fabrication (ALFa) at the University of Waterloo, Canada etc.


F crimp

F-Crimp is a type of solderless electrical crimp connection. It is not related to the F connector common in RF equipment.
It is sometimes referred to as "open-barrel", which is technically a more general term including crimp types such as "Weather Pack" and "Metri Pack".
F-Crimp is a more mechanically robust crimp connection compared to the common barrel-crimp type readily available at retail locations (Radio Shack, Home Depot, "etc."). It also has an optional second crimp section that crimps to the insulation, providing strain relief. Because of these characteristics, automobiles use F-Crimp almost exclusively. F-Crimp was devised to eliminate the need for soldered connections—crimping can be preferred to soldering in mass production because it is easier to reproduce reliable connections. These connections, when made with ratcheting application tooling, provide a solderless, "gas-tight" connection. F-Crimp connections are never soldered as application of solder can lead to fracturing of the wire conductor.
The term F-Crimp was originally coined by AMP Incorporated (now TE Connectivity), however terminals of this style are currently manufactured by multiple companies. Crimpers are available from multiple sources: manufacturers of the connectors typically offer industrial crimp devices for high volume production, and specialized hand tools companies such as Ideal, Eclipse and Greenlee (formerly Paladin) offer dies for hand crimpers. For instance, Ideal die #30-586 and Paladin die #2033 are designed for open barrel / F-Crimp connectors. Non-AMP crimpers are available in "ratcheting" ("Certi-Crimp") and non-ratcheting versions, but only ratcheting types are suitable for production applications, with non-ratcheting types being suitable for occasional, or "field" repairs. Non-ratcheted crimps must "never" be used in "mission critical" applications.


Belur Industrial Area

Belur Industrial Area (Abbreviation : BIA) is an industrial area of the Dharwad city in India and it is one of the biggest industrial areas in Karnataka. lies on the Dharwad-Belgaum Highway. It houses small, medium, and large-scale industries. The industrial area is known for engineering, electrical goods such as: CNC Machine tools, GDC dies & moulds transformers, motors and generators, textile (silk), hydraulics, machine tool industries and Rubber moulding industries.


Decapping

Decapping (decapsulation) or delidding of an integrated circuit is the process of removing the protective cover or integrated heat spreader (IHS) of an integrated circuit so that the contained die is revealed for visual inspection of the micro circuitry imprinted on the die. This process is typically done in order to debug a manufacturing problem with the chip, or possibly to copy information from the device, to check for counterfeit chips or to reverse engineer it. Companies such as TechInsights and ChipRebel decap, take die shots of, and reverse engineer chips for customers. Modern integrated circuits can be encapsulated in plastic, ceramic, or epoxy packages.
Delidding may also be done in an effort to reduce the operating temperatures of an integrated circuit such as a processor, by replacing the thermal interface material (TIM) between the die and the IHS with a higher-quality TIM. With care, it's possible to decap a device and still leave it functional.
Method.
Decapping is usually carried out by chemical etching of the covering, laser cutting, laser evaporation of the covering, plasma etching or mechanical removal of the cover using a milling machine, saw blade or by desoldering and cutting. The process can be either destructive or non-destructive of the internal die.
Chemical etching usually involves subjecting the (if made of plastic) IC package to concentrated or fuming nitric acid, heated concentrated sulfuric acid, white fuming nitric acid or a mixture of the two for some time, possibly while applying heat externally with a hot plate or hot air gun, which dissolve the package while leaving the die intact. The acids are dangerous, so protective equipment such as appropriate gloves, full face respirator with appropriate acid cartridges, a lab coat and a fume hood are required.
Laser decapping scans a high power laser beam across the plastic IC package to vaporize it, while avoiding the actual silicon die.
In a common version of non-destructive, mechanical delidding, one removes the IHS of an IC such as a computer processor using an oven to soften the solder (if present) between the IHS and the die(s) and using a knife to cut the adhesive in the periphery of the IHS, which joins the IHS with the processor package substrate, which is often a specialized printed circuit board often only called a substrate or sometimes an interposer. The die(s) are mounted on the substrate using flip chip.


Prohibited Steps Order

A Prohibited Steps Order is a court order in the United Kingdom common in divorce and separation cases. An example of where a Prohibited Steps Order might be applied for is to prevent one parent from taking a child out of the country.


Grown-junction transistor

The grown-junction transistor was the first type of bipolar "junction" transistor made. It was invented by William Shockley at Bell Labs on June 23, 1948 (patent filed June 26, 1948), six months after the first bipolar point-contact transistor. The first germanium prototypes were made in 1949. Bell Labs announced Shockley’s grown-junction transistor on July 4, 1951.
An NPN grown-junction transistor is made of a single crystal of semiconductor material which has two PN junctions grown into it. During the growth process, a seed crystal is slowly pulled from a bath of molten semiconductor, which then grows into a rod-shaped crystal (boule). The molten semiconductor is doped N-type at the start. At a predetermined moment in the growth process a small pellet of a P-type dopant is added, almost immediately followed by a somewhat larger pellet of an N-type dopant. These dopants dissolve in the molten semiconductor changing the type of semiconductor subsequently grown. The resulting crystal has a thin layer of P-type material sandwiched between sections of N-type material. This P-type layer may be as little as a thousandth of an inch (25 μm) thick. The crystal is sliced, leaving the thin P-type layer in the center of the slice, then cut into bars. Each bar is made into a transistor by soldering its N-type ends to supporting and conducting leads, then welding a very fine gold lead to the central P-type layer, and finally encasing in a hermetically sealed can. A similar process, using the opposite dopants, makes a PNP grown-junction transistor.
The most difficult part of this process is welding the gold wire to the base layer, as the wire may have a larger diameter than the thickness of the base. To facilitate this operation, the gold wire is pointed or flattened until the end is thinner than the base layer. The tip of the gold wire is slid along the bar until electrical resistance measurement shows it is in contact with the base layer. At this time a pulse of current is applied, welding the wire in place. Unfortunately sometimes the weld is too large or slightly off center in the base layer. To avoid shorting the transistor, the gold wire is alloyed with a small amount of the same type dopant as used in the base. This causes the base layer to become slightly thicker at the point of the weld.
Grown-junction transistors rarely operated at frequencies above the audio range, due to their relatively thick base layers. Growing thin base layers was very hard to control and welding the wire to the base became harder the thinner it got. Higher-frequency operation could be obtained by welding a second wire on the opposite side of the base, making a tetrode transistor, and using special biasing on this second base connection.


The 1999 Nigerian House of Representatives elections in Kwara State was held on February 20, 1999, to elect members of the House of Representatives to represent Kwara State, Nigeria.
Results.
Asa/Ilorin West.
APP candidate Gbemisola Ruqayyah Saraki won the election, defeating other party candidates.
Baruten/Kaiama.
PDP candidate Idris S. Abubakar won the election, defeating other party candidates.
Edu/Moro/Patigi.
PDP candidate Yunusa Y. Ahmed won the election, defeating other party candidates.
Ekiti/Isin/Irepodun/Oke-ero.
APP candidate Basair Bola Oni won the election, defeating other party candidates.
Ilorin East/South.
APP candidate Farouk A. O. Farouk won the election, defeating other party candidates.
Offa/Oyun/Ifelodun.
APP candidate Rauf Kolawole Shitu won the election, defeating other party candidates.


Nada Sanders

Nada R. Sanders is an American university professor specializing in forecasting and supply-chain management. She is the Distinguished Professor of Supply Chain Management at the D’Amore-McKim School of Business at Northeastern University. She is also a research scholar, academic editor, reference book author, keynote speaker, business consultant, and corporate board member. Her forecasts describing the impact of the economic crisis on supply disruptions resulting from the COVID-19 pandemic received media coverage. Her latest book "The Humachine" (co-authored with John D. Wood) explores the influence of artificial intelligence over world business and culture.""
Education.
Sanders' university degrees include PhD in operations management and logistics from the Fisher College of Business, Ohio State University, also an MBA and a BS in mechanical engineering.
Career.
Sanders has successively been the "West Chair" at the Neely School of Business at Texas Christian University (2007–2009), "Iacocca Chair" of Supply Chain Management at Lehigh University (2009–2014), and "Distinguished Professor of Supply Chain Management" at the D’Amore-McKim School of Business at Northeastern University (2014 to present).
Her research has centered on topics such as forecasting methods, management technologies, and resilience of supply chains, her works being commonly cited by subject reviews, and referred as reading in university courses covering these matters. Her research is cited in current Wikipedia entries on Forecasting, Global value chain, Electronic business, Logistics, Operations management. Procurement, Supply chain, and Supply chain management.
In 1996, Sanders was ranked among major contributors to the field of production and operations management in the US in preceding years, according to a study from the David Eccles School of Business, University of Utah. She has been a keynote speaker at conferences in her specialties-
As an institutional executive, she has served as a President of the Production and Operations Management Society (POMS, 2019), a Fellow and vice-president of Decision Sciences Institute, a member of the Board of Economic Advisors of the Association of Industries of Massachusetts (AIM), and a member of the Board of Consultants of the International Institute of Forecasters (IIF).
As an editor, Sanders is a member of the editorial boards of several academic journals, among them the Journal of Business Logistics, the Journal of Supply Chain Management, and Production and Operations Management. She has also been a co-editor of several special journal issues, including "Big Data Driven Supply Chain Management" (Production and Operations Management", 2017"), "Big Data Driven Forecasting in Supply Chain Management" (International Journal of Forecasting, 2017), "Perspectives on Big Data" (Operations Management, 2018), "Sustainable Supply Chains in a Digital Interconnected World," (Journal of Business Logistics"," 2019), and "Using Interdisciplinary Research to Address Contemporary SCM Problems" (Journal of Business Logistics, 2016).
Works.
Papers.
Sanders has published over 120 articles in peer-reviewed academic journals which have been cited over 6,400 times; her most cited papers are:
Her most recent articles refer to the impact of Artificial intelligence on business and supply chains:


Wire stripper

A wire stripper is a small, hand-held device used to strip the electrical insulation from electric wires.
Types.
Manual.
A US-style simple manual wire stripper is a pair of opposing blades much like scissors or wire cutters. The addition of a center notch makes it easier to cut the insulation without cutting the wire. This type of wire stripper is used by rotating it around the insulation while applying pressure in order to make a cut around the insulation. Since the insulation is not bonded to the wire, it then pulls easily off the end. This type of wire stripper can be used on wires of any size. Another type of manual wire stripper is very similar to the simple design previously mentioned, except this type has several notches of varying size. This allows the user to match the notch size to the wire size, thereby eliminating the need for twisting, but can only be used on wire sizes that approximately match one of the notches. Once the device is clamped on, the remainder of the wire can simply be pulled out, leaving the insulation behind.
European-style wire strippers look more like a notched pincer, with a grab that is adjusted with a screw.
Compound automatic.
The compound automatic wire stripper was first patented in 1915 by Stuart G. Wood of Brooklyn, NY. The design was refined by Herman Gerhard Jan Voogd of the Netherlands eliminating the awkward 4 bar mechanism taking on the general outline that it has kept since. Wood, now of Rockville IL, added reinforcements, replaceable blades, and blade stops in 1943 The 1943 design was also equipped to block the halves open after stripping to avoid crushing the freshly stripped wire as it returned to its rest position. A second actuation released the mechanism to return to the rest position. The action was further refined by Wood and finally, in 1959, by Eugene D. Hindenburg of DeKalb, IL. The 1959 refinement of the action shifted the sequence of operations so that the stripping blades opened before any other part of the mechanism began to return to the rest position while the clamping jaws retraced the sequence of operation, remaining closed until the handles were fully released.
When engaged, a compound automatic wire stripper first simultaneously grips the wire in one side and in the other side closes its shaped blades cutting the insulation around the conductor. After the sides have completed their strokes the two sides of the mechanism spread apart to push the cut tube of insulation from the end of the conductor. To use it, one simply places the wire in the jaws at the cutting slot matching the size of the conductor and squeezes the handles together. This device allows even a novice to strip most wires very quickly. The compound automatic wire stripper's cutter must be short, because it causes the jaws to twist, as described by Wood in the 1943 patent. All wire strippers are inherently limited to those wire sizes the cutting jaw notches will accommodate. A compound automatic wire stripper's short cutter limits it to fewer notches and a smaller range of wire sizes than most other types of wire strippers. The accuracy of the cutting blade opening determines the smallest conductor that can be reliably stripped. If the cutter opening is too small it will impinge on the conductor causing excess friction and more tension than the wire can withstand. If the cutter opening is too large the tension required to tear the remaining annulus of uncut insulation may be greater than the wire can withstand. Some models have an adjustable grip tension, to adjust the clamping force of the gripping jaw. The knob below the jaw on the yellow automatic strippers in the image below is a grip tension adjustment. Although in principle applicable to wire of any size, compound automatic wire strippers that are widely available have cutters that can accommodate conductors in a range of sizes no larger than 8 AWG nor smaller than 26 AWG, but not the entire range.
Laser wire stripper.
A laser wire stripper is a computer-controlled machine, much like a CNC router, which uses a laser to burn off the insulation of the wire. Laser wire stripping machines are used mostly for very fine gauge wires since they do not damage the conductor. A typical CO2 laser wire stripping machine should be capable of stripping the insulation from any size wire.


Tebis

Tebis ("Technische Entwicklung Beratung und Individuelle Software") is a CAD/CAM software provided by Tebis AG, with headquarters in Martinsried near Munich/Germany.
Development locations: Martinsried and Norderstedt, Germany
International locations: China, Spain, France, Italy, Portugal, Sweden, United Kingdom, USA.
Functionality.
Tebis is a CAD/CAM software for industries such as die, mold or model manufacturing. The software is primarily to create toolpaths for machining operations such as drilling, milling and turning, but also for Wire EDM and sinker EDM. These toolpaths control multi-axis CNC machines. Other applications include manufacturing planning, design, reverse engineering, quality assurance, CNC machining and assembly. The software features interfaces for neutral file formats as well as proprietary formats of third-party manufacturers (STEP 203/214, VDAFS, IGES, DXF, STL, Parasolid, Catia V4/V5, Creo, SolidWorks, NX, JT, Inventor, Nastran, AutoForm).
Industrial application.
The programs are used in manufacturing companies of all sizes, from small and medium-sized companies to OEMs in the automotive and aerospace industries and their suppliers.
The following is a small sampling of companies who use the CAM system from Tebis.
The history of Tebis.
Tebis was founded in 1984. Following initial consulting jobs and business software projects, Tebis shifted its focus after six months to CAD/CAM. The first technical product was a PC-based station, which used a drawing board equipped with a position-measuring system to digitize transparent plans and convert them to scribed programs for milling machines.
Versions 1.0 to 1.0.4 constituted the first Tebis CAD/CAM system. As one of the first 3D systems, Tebis ran exclusively on PCs (DOS). Two monitors were required for its operation: One monitor displayed the real commands, while the other showed the geometries in 4 panels. The input commands were entered using a digitizer tablet. The milling programs were calculated only for individual surfaces. Because of the small RAM (256 bytes) in the NC machines of the 1980s, Tebis provided a DNC connection to enable postprocessing via a V24 line next to the NC machine.
The Tebis Version 2.0 with a graphical user interface was introduced in 1989. It is still used today in a much more advanced form, and is distinct from common Windows interfaces. This version made it possible to animate geometries onscreen in real-time. Tebis Automill technology, which allows users to calculate milling paths across surfaces, was introduced in Version 2.1.
Tebis Version 3.0 was presented in 1993. The system was modularized and expanded for operation under the SCO UNIX, HP-UX, IRIX and AIX operating systems. Version 3.1 included the Milling Wizard, version V3.2 featured interactive CAD and version V3.3 offered the first integration of a tool library and parameterized administration for all NC calculations. In Version 3.4, modules for the simulation of machining at a virtual CNC machine the design of electrodes for EDM, and 2.5D milling and drilling were added. Starting with Version 3.5, variable machining templates can be used for even better NC programming automation. For the first time this version also included the Job Manager as a central control element for all machining steps. The CAD module for BREP design was integrated in the software, enabling Tebis to be used for the entire manufacturing process in die, mold and model manufacturing. Version 4.0 was provided with a new user interface specifically designed for CAD/CAM applications and a new platform for 2.5D and 3D feature-based NC automation. For the first time, this version supported CNC lathes and industrial robots, and the manufacturing technologies of laser hardening and laser weld cladding.
The current Tebis Version 4.1 was launched in 2020 with an internally-developed parametric-associative CAD system base. The hybrid CAD system combines free-form surfaces, solids and digitized data and provides Tebis template technology also in the CAD environment. Parametric CAD templates automate design and CAD manufacturing preparation. The user interface has also been optimized in terms of simplicity and automation for CAM users.
Tebis is one of the global market leaders in CAM software. The owner-managed company also has its own consulting unit working with companies primarily in die, mold and model manufacturing. Services include industry-specific process and management consulting and optimizing the processes of these companies.
After acquiring a division of ID Ingenieurgesellschaft für Datentechnik mbH, Tebis now also offers a manufacturing execution system (MES) called ProLeiS that can be integrated in the CAD/CAM application.


Prusa i3

The Prusa i3 is a family of fused deposition modeling 3D printers, manufactured by Czech company Prusa Research under the trademarked name Original Prusa i3. Part of the RepRap project, Prusa i3 printers were called the most used 3D printer in the world in 2016. The first Prusa i3 was designed by Josef Průša in 2012, and was released as a commercial kit product in 2015. The latest model (Prusa MK4 on sale as of March 2023) is available in both kit and factory assembled versions. The Prusa i3's comparable low cost and ease of construction and modification made it popular in education and with hobbyists and professionals, with the Prusa i3 model MK2 printer receiving several awards in 2016.
The i3 series is released under an open source license, so many other companies and individuals have made variants of the printer.
Models.
RepRap Mendel.
First conceived in 2009, RepRap Mendel 3D printers were designed to be assembled from 3D printed parts and commonly available off-the-shelf components (referred to as "vitamins," as they cannot be produced by the printer itself). These parts include threaded rods, leadscrews, smooth rods and bearings, screws, nuts, stepper motors, control circuit boards, and a "hot end" to melt and place thermoplastic materials. A Cartesian mechanism permits placement of material anywhere in a cubic volume; this design has continued throughout development of the i3 series. The flat "print bed" (the surface on which parts are printed) is movable in one axis (Y), while two horizontal and two vertical rods permit tool motion in two axes, designated X and Z.
Prusa Mendel.
Josef Průša, a core developer of the RepRap project who had previously developed a PCB heated "print bed", adapted and simplified the RepRap Mendel design, reducing the time to print 3D plastic parts from 20 to 10 hours, and including 3D printed bushings in place of regular bearings. First announced in September 2010, the printer was dubbed Prusa Mendel by Průša himself. According to the RepRap wiki, "Prusa Mendel is the Ford Model T of 3D printers."
Prusa Mendel (Iteration 2).
Průša streamlined his Mendel design, releasing "Prusa Iteration 2" in November 2011. Parts changes allowed for snap-fit assembly (no glue required); fewer tools were needed to construct and maintain this version. Although not required, fine-pitch manufactured pulleys and LM8UU linear bearings were recommended over printed equivalents for "professional" results.
Prusa i3.
In May 2012, Průša released a major redesign, focused on ease of construction and use, and no longer structured around the simplest available common hardware as previous RepRap printers were. The Prusa i3 design replaced the threaded-rod, triangular Z axis frame construction with a rigid, single-piece water jet cut aluminium vertical frame. This improved printing speed and accuracy by eliminating the need to erect, align and tighten the upper supports on the Mendel, which were easily skewed or twisted out of alignment from the base. M10 threaded rods were still used to support the heated bed Y axis. It used a single piece, food safe stainless steel hot end called the Prusa Nozzle which printed with 3 mm filament, and used M5 threaded rods as lead screws instead of M8.
In 2015, Průša released an i3 full kit under the brand name "Original Prusa i3". For about three months, the Prusa i3 was delivered set up for a proprietary 3 mm filament diameter (which retrospectively has been dubbed the "mark zero"), before the Mk1 update when it was switched to the more common filament diameter of 1.75 mm.
Prusa i3 MK2 and MK2S.
Průša released the Prusa i3 MK2 in May 2016. It was the first hobby 3D printer with mesh bed leveling and automatic geometry skew correction for all three axes. Features included a larger build volume, custom stepper motors with integrated lead screws, a non-contact inductive sensor for auto-leveling, and a rewritten version of the Marlin firmware. Other new features include a polyetherimide print surface, Rambo controller board and an E3D V6 Full hotend. The Prusa MK2 became the first RepRap printer to be supported by Windows 10 Plug-and-Play USB ID.
In March 2017, Průša announced on his blog that the revised Prusa i3 MK2S would ship in place of the Prusa i3 MK2. Enhancements cited include U-bolts to hold the LM8UU bearings where cable ties had been used, higher quality bearings and rods, an improved mount for the inductance sensor, improved cable management, and a new electronics cover. An upgrade kit was offered to owners of the MK2 to add these improvements.
Prusa i3 MK3 and MK2.5.
In September 2017, Prusa i3 MK3 was released, marketed as "bloody smart." Starting with this model, the base and Y axis were assembled with aluminum extrusion, eliminating the last of the structural threaded rods from the Mendel design. Included were a new extruder with dual Bondtech drive-gears, quieter fans with RPM monitoring, faster print speeds, an updated bed leveling sensor, a new electronics board named "Einsy", quieter stepper motors with 128 step microstepping drivers and a magnetic heatbed with interchangeable PEI-coated steel sheets. Electrical components were updated to work with the new 24 volt power supply. The printer also offers dedicated sockets to connect Raspberry Pi Zero W running a fork of the open source OctoPrint software for wireless printing.
Ease-of-use features included a filament detector, allowing the printer to load filament when it is inserted, and to pause printing if the filament is jammed or runs out; error-correcting stepper motor drivers preventing layer shifts due to skipped steps; and recovery after power outages. The ambient temperature sensor both confirms suitable environment temperature and detects overheated electrical connections on the main board.
Existing MK2 and MK2S users were offered a $199 partial upgrade named MK2.5, limited to features which are cheaper to upgrade. After negative feedback from the community, Prusa made available a more expensive $500 MK2S to MK3 full upgrade.
Prusa i3 MK3S and MK3S+.
In February 2019, Prusa i3 MK3S was released, along with the Multi Material Upgrade 2S (MMU2S), which allows selecting any of 5 different materials for printing together automatically. MK3S changes include a simplified opto-mechanical filament sensor, improved print cooling, and easier access to service the extruder.
Prusa made a running change starting November, 2020 to the Prusa i3 MK3S+. This model has a revised bed leveling sensor and minor parts changes.
Prusa i3 MK4.
In March 2023, Prusa announced the i3 MK4 and the Multi Material Unit version 3 (MMU3). This model features a new i3 version of their "Nextruder" extruder system first seen on the Prusa XL, no-adjustment load cell bed leveling, a modular replaceable all-metal hot end, a color touchscreen, and die-cast aluminum frame, Y-carriage (heat bed support), and extruder frame. The 32-bit main processor board includes additional safety and monitoring circuits, a network connector, a port for the MMU3, and a Wi-fi module. This is Prusa's first Mendel-based design to include support for local and cloud monitoring and support.
Switching to 0.9 degree stepping motors, and the addition of input shaping and pressure advance, allow the Mendel-style design to print faster while avoiding ringing artifacts and other undesirable patterns imposed on the object being made, even though it does not have the advantages of the box-like structure of CoreXY printers. However, Průša has stated that print quality, not maximum speed, is their design goal. There is a provision for an accelerometer, often used in 3D printing for self-tuning of input shaping, but that component is not included in the final design.
When announced, software for input shaping, touch screen operation, and sensor data collection were not finished, and the Multi Material Unit was not ready for release. Upgrade kits for earlier models likewise were not available for shipping.
Other Prusa models.
Following the MK3S, Prusa introduced unrelated models such as the Prusa SL1 (SLA printer), the Prusa Mini (with a cantilever arm) and Prusa XL (using a Core XY method inside a full-frame structure). These printers are not iterations of the Mendel frame design.
Variants.
With all aspects of the design freely available under open source and open hardware terms, companies and individuals around the world have produced Prusa i3 copies, variants, and upgrades in assembled and kit form, with thousands offered for sale as early as 2015. Rather than compete directly with these, Prusa Research's strategy is to pursue continual refinement of its designs.
Components and materials.
Plastic parts.
All Prusa i3 models use 3D printing filament as feedstock to make parts.
Like other RepRap printers the Prusa i3 is capable of creating many of its own parts, with the designs freely available for repairs, replication, and redesign. Formerly these were printed in ABS plastic; Prusa Research now uses mostly PETG instead. Prusa Research maintains a "print farm" of 600 3D printers (as of October 2021) to manufacture the plastic parts for Original Prusa branded products.
Control system.
When the Prusa i3 design was first introduced in 2012, RepRap printers frequently used Open Hardware controllers such as an Arduino Mega combined with an Arduino shield providing the remaining circuitry, such as the RAMPS board. All-in-one versions such as the RAMBo board were becoming available. As a commercial product, Original Prusa i3 up to MK2 used Mini-Rambo. MK3 versions switched to Einsy Rambo boards to provide desired features such as quieter operation. The i3 MK4 uses xBuddy, the first 32-bit board used in the i3 series.
All Original Prusa products use Marlin 3D printing firmware.
First layer control and bed leveling.
When extruding the first layer, the print head must be a precise distance away from the print bed for proper adhesion. Many 3D printers rely on the user to complete this process by adjusting the height of the bed at several locations ("bed leveling"). To automate this process, Prusa i3 models from the MK2 in 2016 have a sensor to detect the height of the printbed at different locations, and then adjust for it when printing ("auto-leveling").
The PINDA series requires an electronic Z-height adjustment which may vary for different heat bed surfaces or different nozzles. The load cell sensor automatically compensates for variations in nozzle size, and thickness and expansion of the heated bed surface, eliminating stored settings for the purpose.
Frames.
The distinguishing feature of the i3 from its predecessors is the vertical frame, which can take many forms. These include single sheet frames cut from steel or acrylic, box frames from plywood or medium-density fibreboard, and Lego. Inexpensive aluminum extrusion is commonly used, both by printer enthusiasts and by manufacturers of "clone" i3 printers. Some mass market i3 variants, such as many Shenzhen Creality products, use rollers against the extruded frame itself instead of precision rods and bearings to reduce cost and complexity.
Extruders.
Beyond the standard Prusa i3 filament extruders, others have created aftermarket extruders and enthusiast tool heads, including a MIG welder and a laser cutter. Průša offered a collection of functional cooking tools and programs under the name "MK3 Master Chef Upgrade" as an April Fools' Day gag in 2018.


Ceramic mold casting

Ceramic mold casting, also known ambiguously as ceramic molding, is a group of metal casting processes that use ceramics as the mold material. It is a combination of plaster mold casting and investment casting. There are two types of ceramic mold casting: the "Shaw process" and the "Unicast process".
These casting processes are commonly used to make tooling, especially drop forging dies, but also injection molding dies, die casting dies, glass molds, stamping dies, and extrusion dies.
Shaw process.
The ', also known as the ', uses a mixture of refractory aggregate, hydrolyzed ethyl silicate, alcohol, and a gelling agent to create a mold. This slurry mixture is poured into a slightly tapered flask and a reusable pattern ("i.e." the item used to create the shape of the mold) is used. The slurry hardens almost immediately to a rubbery state (the consistency of vulcanized rubber). The flask and pattern is then removed. Then a torch is used to ignite the mold, which causes most of the volatiles to burn-off and the formation of ceramic microcrazes (microscopic cracks). These cracks are important, because they allow gases to escape while preventing the metal from flowing through; they also ease thermal expansion and contraction during solidification and shrinkage. After the burn-off, the mold is baked at to remove any remaining volatiles. Prior to pouring metal, the mold is pre-warmed to control shrinkage.
Unicast process.
The "Unicast process" is very similar to the Shaw process, except it does not require the mold to be ignited and then be cured in a furnace. Instead, the mold is partially cured so the pattern can be removed and it is then completely cured by firing it at approximately . If a metal with a low melting point is cast then the firing can be skipped, because the mold has enough strength in the "green state" (un-fired).
Characteristics.
The main advantages of ceramic molds are: a reusable pattern (the item used to create the shape of the mold), excellent surface finish, close dimensional tolerances, thin cross-sections, and intricate shapes can be cast. For undercuts and other difficult to cast features, part of the pattern can be made from wax in conjunction with a standard pattern; essentially using investment and ceramic mold casting techniques together. The main disadvantages are: it is only cost effective for small- to medium-sized production runs and the ceramic is not reusable. Ferrous and high-temperature non-ferrous are most commonly cast with these processes; other materials cast include: aluminum, copper, magnesium, titanium, and zinc alloys.
Weight limits are 100 grams to several thousand kilograms (3.5 oz to several tons). Cross-sections as thin as are possible, with no upper limit. Typical tolerances are 0.1 mm for the first 25 mm (0.005 in for the first inch) and 0.003 mm per additional mm (0.003 in per each additional in). A draft of 1° is typically required. The typical surface finish is 2–4 um (75–150 uin) RMS.


Full-mold casting

Full-mold casting is an evaporative-pattern casting process which is a combination of sand casting and lost-foam casting. It uses an expanded polystyrene foam pattern which is then surrounded by sand, much like sand casting. The metal is then poured directly into the mold, which vaporizes the foam upon contact.
Process.
First, a pattern is usually made from polystyrene foam, which can be done many different ways. For small volume runs the pattern can be hand cut or machined from a solid block of foam; if the geometry is simple enough it can even be cut using a hot-wire foam cutter.
If the volume is large, then the pattern can be mass-produced by a process similar to injection molding. Pre-expanded beads of polystyrene are injected into a preheated aluminum mold at low pressure. Steam is then applied to the polystyrene which causes it to expand more to fill the die. The final pattern is approximately 97.5% air and 2.5% polystyrene.
The finished patterns can be hot glued to pre-made pouring basins, runners, and risers to form the final pattern. The pattern is then coated with a refractory material. The coated pattern (2) is placed in a flask and packed carefully with green sand (4) or a chemically bonded sand.
Finally, the molten metal (1) is poured into the mold, which vaporizes the foam (3) allowing the metal to fill the entire mold. The vapor is simultaneously extracted from the flask through the sand.
The casting is allowed to cool and then dumped out of the flask (5) ready to use. The sand does not need to be reprocessed so it can be directly reused.
Details.
The minimum wall thickness for a full-mold casting is . Typical dimensional tolerances are 0.3% and typical surface finishes are from 2.5 to 25 µm (100 to 1000 µin) RMS. The size range is from to several tonnes (tons).
Full-mold casting is often used to produce cylinder heads, engine blocks, pump housings, automotive brake components, and manifolds. Commonly employed materials include aluminium, iron, steel, nickel alloys, and copper alloys.
Advantages and disadvantages.
This casting process is advantageous for very complex castings, that would regularly require cores. It is also dimensionally accurate, requires no draft, and has no parting lines so no flash is formed. As compared to investment casting, it is cheaper because it is a simpler process and the foam is cheaper than the wax. Risers are not usually required due to the nature of the process; because the molten metal vaporizes the foam the first metal into the mold cools more quickly than the rest, which results in natural directional solidification.
The two main disadvantages are that pattern costs can be high for low volume applications and the patterns are easily damaged or distorted due to their low strength. If a die is used to create the patterns there is a large initial cost.
History.
The first patent for an evaporative-pattern casting process was filed in April 1956, by H.F. Shroyer. He patented the use of foam patterns embedded in traditional green sand for metal casting.


Shear forming

Shear forming, also referred as shear spinning, is similar to metal spinning. In shear spinning the area of the final piece is approximately equal to that of the flat sheet metal blank. The wall thickness is maintained by controlling the gap between the roller and the mandrel. In shear forming a reduction of the wall thickness occurs.
Before the 1950s, spinning was performed on a simple turning lathe. When new technologies were introduced to the field of metal spinning and powered dedicated spinning machines were available, shear forming started its development in Sweden.
Schematics.
Figure 2 shows the schematics of a shear forming process.
1. A sheet metal blank is placed between the mandrel and the chuck of the spinning machine. The mandrel has the interior shape of the desired final component.
2. A roller makes the sheet metal wrap the mandrel so that it takes its shape.
As can be seen, s1 which is the initial wall thickness of the workpiece is reduced to s0.
Workpiece and roller tool profiles.
In shear forming, the starting workpiece can have circular or rectangular cross sections. On the other hand, the profile shape of the final component can be concave, convex or a combination of these two.
A shear-forming machine looks very much like a conventional spinning machine, except that it has to be much more robust to withstand the higher forces necessary to perform the shearing operation.
The design of the roller must be considered carefully, because it affects the shape of the component, the wall thickness, and dimensional accuracy. The smaller the tool nose radius, the higher the stresses and poorest thickness uniformity achieved.
Spinnability.
Spinnability, sometimes referred as shear spinnability, can be defined as the ability of a metal to undergo shear spinning deformation without exceeding its tensile strength and tearing. Published work on spinnability is available from the authors Kegg and Kalpakcioglu.
Kegg predicted that for materials with a tensile reduction of 80%, the limiting spinning reduction will be equal or greater than 80%.
Kalpakciouglu concluded that for metals with a true fracture strain of 0.5 or greater, there is a maximum limit for the shear forming reduction. For materials with a true strain below 0.5, the spinnability depends on the ductility of the material.
Highly spinnable materials include ductile materials like aluminum and certain steel alloys.
Importance of shear forming operations in manufacturing.
Shear forming and conventional spinning are being used less than other manufacturing processes such as deep drawing and ironing. Being able to achieve almost any shape, thin sectioned parts, makes spinning a versatile process used widely in the production of lightweight items. Other advantages of shear spinning include the good mechanical properties of the final item and a very good surface finish.
Typical components produced by mechanically powered spinning machines include rocket nose cones, gas turbine engine and dish aerials.
Flow forming.
Flow Forming is an incremental metal-forming technique in which a disk or tube of metal is formed over a mandrel by one or more rollers using tremendous pressure. The roller deforms the workpiece, forcing it against the mandrel, both axially lengthening and radially thinning it. Since the pressure exerted by the roller is highly localized and the material is incrementally formed, often there is a net savings in energy in forming over drawing or ironing processes. However, these savings are often not realized because of the inherent difficulties in predicting the resulting deformation for a given roller path. Flow forming subjects the workpiece to a great deal of friction and deformation. These two factors may heat the workpiece to several hundred degrees if proper cooling fluid is not utilized.
Flow forming is often used to manufacture automobile wheels and can be used to draw a wheel to net width from a machined blank.
During flow forming, the workpiece is cold worked, changing its mechanical properties, so its strength becomes similar to that of forged metal.
References.
 3. https://www.pmfind.com/benefits/flowforming-process-benefits-process


Ultrasonic machining

Ultrasonic machining is a subtractive manufacturing process that removes material from the surface of a part through high frequency, low amplitude vibrations of a tool against the material surface in the presence of fine abrasive particles. The tool travels vertically or orthogonal to the surface of the part at amplitudes of 0.05 to 0.125 mm (0.002 to 0.005 in.). The fine abrasive grains are mixed with water to form a slurry that is distributed across the part and the tip of the tool. Typical grain sizes of the abrasive material range from 100 to 1000, where smaller grains (higher grain number) produce smoother surface finishes.
Ultrasonic vibration machining is typically used on brittle materials as well as materials with a high hardness due to the microcracking mechanics.
Process.
An ultrasonically vibrating machine consists of two major components, an electroacoustic transducer and a sonotrode, attached to an electronic control unit with a cable. The abrasive grains in the slurry now act as a free cutting tool as they strike the workpiece thousands of times per second. An electronic oscillator in the control unit produces an alternating current oscillating at a high frequency, usually between 18 and 40 kHz in the ultrasonic range. The transducer converts the oscillating current to a mechanical vibration. Two types of transducers have been used in ultrasonic machining; either piezoelectric or magnetostrictive:
The transducer vibrates the sonotrode at low amplitudes and high frequencies. The sonotrode is usually made of low carbon steel. A constant stream of abrasive slurry flows between the sonotrode and work piece. This flow of slurry allows debris to flow away from the work cutting area. The slurry usually consists of abrasive boron carbide, aluminum oxide or silicon carbide particles in a suspension of water (20 to 60% by volume). The sonotrode removes material from the work piece by abrasion where it contacts it, so the result of machining is to cut a perfect negative of the sonotrode's profile into the work piece. Ultrasonic vibration machining allows extremely complex and non-uniform shapes to be cut into the workpiece with extremely high precision.
Machining time depends on the workpiece's strength, hardness, porosity and fracture toughness; the slurry's material and particle size; and the amplitude of the sonotrode's vibration. The surface finish of materials after machining depends heavily on hardness and strength, with softer and weaker materials exhibiting smoother surface finishes. The inclusion of microcrack and microcavity features on the materials surface depend highly on the crystallographic orientation of the work piece's grains and the materials fracture toughness.
Mechanics.
Ultrasonic vibration machining physically operates by the mechanism of microchipping or erosion on the work piece's surface. Since the abrasive slurry is kept in motion by high frequency, low amplitude vibrations, the impact forces of the slurry are significant, causing high contact stresses. These high contact stresses are achieved by the small contact area between the slurry's particles and the work piece's surface. Brittle materials fail by cracking mechanics and these high stresses are sufficient to cause micro-scale chips to be removed from its surface. The material as a whole does not fail due to the extremely localized stress regions. The average force imparted by a particle of the slurry impacting the work piece's surface and rebounding can be characterized by the following equation:
Where "m" is the mass of the particle, "v" is the velocity of the particle when striking the surface and "to" is the contact time, which can be approximated according to the following equation:
Where "r" is the radius of the particle, "co" is the elastic wave velocity of the work piece, "E" is the work pieces Young's Modulus and "ρ" is the materials density.
Types.
Rotary ultrasonic vibration machining.
In rotary ultrasonic vibration machining (RUM), the vertically oscillating tool is able to revolve about the vertical center line of the tool. Instead of using an abrasive slurry to remove material, the surface of the tool is impregnated with diamonds that grind down the surface of the part. Rotary ultrasonic machines are specialized in machining advanced ceramics and alloys such as glass, quartz, structural ceramics, Ti-alloys, alumina, and silicon carbide. Rotary ultrasonic machines are used to produce deep holes with a high level of precision.
Rotary ultrasonic vibration machining is a relatively new manufacturing process that is still being extensively researched. Currently, researchers are trying to adapt this process to the micro level and to allow the machine to operate similar to a milling machine.
Chemical-assisted ultrasonic vibration machining.
In chemical-assisted ultrasonic machining (CUSM), a chemically reactive abrasive fluid is used to ensure greater machining of glass and ceramic materials. Using an acidic solution, such as hydrofluoric acid, machining characteristics such as material removal rate and surface quality can be improved greatly compared to traditional ultrasonic machining. While time spent machining and surface roughness decrease with CUSM, the entrance profile diameter is slightly larger than normal due to the additional chemical reactivity of the new slurry choice. In order to limit the extent of this enlargement, the acid content of the slurry must be carefully selected as to ensure user safety and a quality product.
Applications.
Since ultrasonic vibration machining does not use subtractive methods that may alter the physical properties of a workpiece, such as thermal, chemical, or electrical processes, it has many useful applications for materials that are more brittle and sensitive than traditional machining metals. Materials that are commonly machined using ultrasonic methods include ceramics, carbides, glass, precious stones and hardened steels. These materials are used in optical and electrical applications where more precise machining methods are required to ensure dimensional accuracy and quality performance of hard and brittle materials. Ultrasonic machining is precise enough to be used in the creation of microelectromechanical system components such as micro-structured glass wafers.
In addition to small-scale components, ultrasonic vibration machining is used for structural components because of the required precision and surface quality provided by the method. The process can safely and effectively create shapes out of high-quality single crystal materials that are often necessary but difficult to generate during normal crystal growth. As advanced ceramics become a greater part of the structural engineering realm, ultrasonic machining will continue to provide precise and effective methods of ensuring proper physical dimensions while maintaining crystallographic properties.
Advantages.
Ultrasonic vibration machining is a unique non-traditional manufacturing process because it can produce parts with high precision that are made of hard and brittle materials which are often difficult to machine. Additionally, ultrasonic machining is capable of manufacturing fragile materials such as glass and non-conductive metals that can not be machined by alternative methods such as electrical discharge machining and electrochemical machining. Ultrasonic machining is able to produce high-tolerance parts because there is no distortion of the worked material. The absence of distortion is due to no heat generation from the sonotrode against the work piece and is beneficial because the physical properties of the part will remain uniform throughout. Furthermore, no burrs are created in the process, thus fewer operations are required to produce a finished part.
Disadvantages.
Because ultrasonic vibration machining is driven by microchipping or erosion mechanisms, the material removal rate of metals can be slow and the sonotrode tip can wear down quickly from the constant impact of abrasive particles on the tool. Moreover, drilling deep holes in parts can prove difficult as the abrasive slurry will not effectively reach the bottom of the hole. Note, rotary ultrasonic machining is efficient at drilling deep holes in ceramics because the absence of a slurry cutting fluid and the cutting tool is coated in harder diamond abrasives. In addition, ultrasonic vibration machining can only be used on materials with a hardness value of at least 45 HRC.


Grinding (abrasive cutting)

Grinding is a type of abrasive machining process which uses a grinding wheel as cutting tool.
A wide variety of machines are used for grinding, best classified as portable or stationary:
Milling practice is a large and diverse area of manufacturing and toolmaking. It can produce very fine finishes and very accurate dimensions; yet in mass production contexts, it can also rough out large volumes of metal quite rapidly. It is usually better suited to the machining of very hard materials than is "regular" machining (that is, cutting larger chips with cutting tools such as tool bits or milling cutters), and until recent decades it was the only practical way to machine such materials as hardened steels. Compared to "regular" machining, it is usually better suited to taking very shallow cuts, such as reducing a shaft's diameter by half a thousandth of an inch or 12.7 μm.
Grinding is a subset of cutting, as grinding is a true metal-cutting process. Each grain of abrasive functions as a microscopic single-point cutting edge (although of high negative rake angle), and shears a tiny chip that is analogous to what would conventionally be called a "cut" chip (turning, milling, drilling, tapping, etc.) . However, among people who work in the machining fields, the term "cutting" is often understood to refer to the macroscopic cutting operations, and "grinding" is often mentally categorized as a "separate" process. This is why the terms are usually used separately in shop-floor practice.
Lapping and sanding are subsets of grinding.
Processes.
Selecting which of the following grinding operations to be used is determined by the size, shape, features and the desired production rate.
Creep-feed grinding.
Creep-feed grinding (CFG) was a grinding process which was invented in Germany in the late 1950s by Edmund and Gerhard Lang. Normal grinding is used primarily to finish surfaces. But CFG is used for high rates of material removal, competing with milling and turning as a manufacturing process choice. CFG has grinding depth up to 6 mm (0.236 inches) and workpiece speed is low. Surfaces with a softer-grade resin bond are used to keep workpiece temperature low and an improved surface finish up to 1.6 μm Rmax.
CFG can take 117 s to remove of material. Precision grinding would take more than 200 s to do the same. CFG has the disadvantage of a wheel that is constantly degrading, requires high spindle power , and is limited in the length of part it can machine.
To address the problem of wheel sharpness, continuous-dress creep-feed grinding (CDCF) was developed in 1970s. The wheel is dressed constantly during machining in CDCF process and keeps the wheel in a state of specified sharpness. It takes only 17 s to remove of material, a huge gain in productivity. 38 hp (28 kW) spindle power is required, with a low to conventional spindle speeds. The limit on part length was erased.
High-efficiency deep grinding (HEDG) is another type of grinding. This process uses plated superabrasive wheels. These wheels never need dressing and last longer than other wheels. This reduces capital equipment investment costs. HEDG can be used on long part lengths and removes material at a rate of in 83 s. HEDG requires high spindle power and high spindle speeds.
Peel grinding, patented under the name of Quickpoint in 1985 by Erwin Junker Maschinenfabrik, GmbH in Nordrach, Germany, uses a thin superabrasive grinding disk oriented almost parallel to a cylindrical workpiece and operates somewhat like a lathe turning tool.
Ultra-high speed grinding (UHSG) can run at speeds higher than 40,000 fpm (200 m/s), taking 41 s to remove of material, but is still in the research and development (R&D) stage. It also requires high spindle power and high spindle speeds.
Cylindrical grinding.
Cylindrical grinding (also called center-type grinding) is used to grind the cylindrical surfaces and shoulders of the workpiece. The workpiece is mounted on centers and rotated by a device known as a lathe dog or center driver. The abrasive wheel and the workpiece are rotated by separate motors and at different speeds. The table can be adjusted to produce tapers. The wheel head can be swiveled. The five types of cylindrical grinding are: outside diameter (OD) grinding, inside diameter (ID) grinding, plunge grinding, creep feed grinding, and centerless grinding.
A cylindrical grinder has a grinding (abrasive) wheel, two centers that hold the workpiece, and a chuck, grinding dog, or other mechanism to drive the work. Most cylindrical grinding machines include a swivel to allow the forming of tapered pieces. The wheel and workpiece move parallel to one another in both the radial and longitudinal directions. The abrasive wheel can have many shapes. Standard disk-shaped wheels can be used to create a tapered or straight workpiece geometry, while formed wheels are used to create a shaped workpiece. The process using a formed wheel creates less vibration than using a regular disk-shaped wheel.
Tolerances for cylindrical grinding are held within ± for diameter and ± for roundness. Precision work can reach tolerances as high as ± for diameter and ± for roundness. Surface finishes can range from to , with typical finishes ranging from .
Surface grinding.
"Surface grinding" uses a rotating abrasive wheel to remove material, creating a flat surface. The tolerances that are normally achieved with grinding are ± for grinding a flat material and ± for a parallel surface.
The surface grinder is composed of an abrasive wheel, a workholding device known as a chuck, either electromagnetic or vacuum, and a reciprocating table.
Grinding is commonly used on cast iron and various types of steel. These materials lend themselves to grinding because they can be held by the magnetic chuck commonly used on grinding machines and do not melt into the cutting wheel, clogging it and preventing it from cutting. Materials that are less commonly ground are aluminum, stainless steel, brass, and plastics. These all tend to clog the cutting wheel more than steel and cast iron, but with special techniques it is possible to grind them.
Others.
Centerless grinding is when the workpiece is supported by a blade instead of by centers or chucks. Two wheels are used. The larger one is used to grind the surface of the workpiece and the smaller wheel is used to regulate the axial movement of the workpiece. Types of centerless grinding include through-feed grinding, in-feed/plunge grinding, and internal centerless grinding.
Electrochemical grinding is a type of grinding in which a positively charged workpiece in a conductive fluid is eroded by a negatively charged grinding wheel. The pieces from the workpiece are dissolved into the conductive fluid.
Electrolytic in-process dressing (ELID) grinding is one of the most accurate grinding methods. In this ultra precision grinding technology the grinding wheel is dressed electrochemically and in-process to maintain the accuracy of the grinding. An ELID cell consists of a metal bonded grinding wheel, a cathode electrode, a pulsed DC power supply and electrolyte. The wheel is connected to the positive terminal of the DC power supply through a carbon brush whereas the electrode is connected to the negative pole of the power supply. Usually alkaline liquids are used as both electrolytes and coolant for grinding. A nozzle is used to inject the electrolyte into the gap between wheel and electrode. The gap is usually maintained to be approximately 0.1mm to 0.3 mm. During the grinding operation one side of the wheel takes part in the grinding operation whereas the other side of the wheel is being dressed by electrochemical reaction. The dissolution of the metallic bond material is caused by the dressing which in turns results continuous protrusion of new sharp grits.
 is a specialized type of cylindrical grinding where the grinding wheel has the exact shape of the final product. The grinding wheel does not traverse the workpiece.
Internal grinding is used to grind the internal diameter of the workpiece. Tapered holes can be ground with the use of internal grinders that can swivel on the horizontal.
Pre-grinding - When a new tool has been built and has been heat-treated, it is pre-ground before welding or hardfacing commences. This usually involves grinding the outside diameter (OD) slightly higher than the finish grind OD to ensure the correct finish size.
Grinding wheel.
A grinding wheel is an expendable wheel used for various grinding and abrasive machining operations. It is generally made from a matrix of coarse abrasive particles pressed and bonded together to form a solid, circular shape, various profiles and cross sections are available depending on the intended usage for the wheel. Grinding wheels may also be made from a solid steel or aluminium disc with particles bonded to the surface.
Lubrication.
The use of fluids in a grinding process is often necessary to cool and lubricate the wheel and workpiece as well as remove the chips produced in the grinding process. The most common grinding fluids are water-soluble chemical fluids, water-soluble oils, synthetic oils, and petroleum-based oils. It is imperative that the fluid be applied directly to the cutting area to prevent the fluid being blown away from the piece due to rapid rotation of the wheel.
The workpiece.
Workholding methods.
The workpiece is manually clamped to a lathe dog, powered by the faceplate, that holds the piece in between two centers and rotates the piece. The piece and the grinding wheel rotate in opposite directions and small bits of the piece are removed as it passes along the grinding wheel. In some instances special drive centers may be used to allow the edges to be ground. The workholding method affects the production time as it changes set up times.
Workpiece materials.
Typical workpiece materials include aluminum, brass, plastics, cast iron, mild steel, and stainless steel. Aluminum, brass and plastics can have poor to fair machinability characteristics for cylindrical grinding. Cast Iron and mild steel have very good characteristics for cylindrical grinding. Stainless steel is very difficult to grind due to its toughness and ability to work harden, but can be worked with the right grade of grinding wheels.
Workpiece geometry.
The final shape of a workpiece is the mirror image of the grinding wheel, with cylindrical wheels creating cylindrical pieces and formed wheels creating formed pieces. Typical sizes on workpieces range from 0.75 in to 20 in (18 mm to 1 m) and 0.80 in to 75 in (2 cm to 4 m) in length, although pieces from 0.25 in to 60 in (6 mm to 1.5 m) in diameter and 0.30 in to 100 in (8 mm to 2.5 m) in length can be ground. Resulting shapes can be straight cylinders, straight-edged conical shapes, or even crankshafts for engines that experience relatively low torque.
Effects on workpiece materials.
Chemical property changes include an increased susceptibility to corrosion because of high surface stress.
Mechanical properties will change due to stresses put on the part during finishing. High grinding temperatures may cause a thin martensitic layer to form on the part, which will lead to reduced material strength from microcracks.
Physical property changes include the possible loss of magnetic properties on ferromagnetic materials.