Digital prototyping

Digital Prototyping gives conceptual design, engineering, manufacturing, and sales and marketing departments the ability to virtually explore a complete product before it's built. Industrial designers, manufacturers, and engineers use Digital Prototyping to design, iterate, optimize, validate, and visualize their products digitally throughout the product development process. Innovative digital prototypes can be created via CAutoD through intelligent and near-optimal iterations, meeting multiple design objectives (such as maximised output, energy efficiency, highest speed and cost-effectiveness), identifying multiple figures of merit, and reducing development gearing and time-to-market. Marketers also use Digital Prototyping to create photorealistic renderings and animations of products prior to manufacturing. Companies often adopt Digital Prototyping with the goal of improving communication between product development stakeholders, getting products to market faster, and facilitating product innovation.
Digital Prototyping goes beyond simply creating product designs in 3D. It gives product development teams a way to assess the operation of moving parts, to determine whether or not the product will fail, and see how the various product components interact with subsystems—either pneumatic or electric. By simulating and validating the real-world performance of a product design digitally, manufacturers often can reduce the number of physical prototypes they need to create before a product can be manufactured, reducing the cost and time needed for physical prototyping. Many companies use Digital Prototyping in place of, or as a complement to, physical prototyping.
Digital Prototyping changes the traditional product development cycle from design>build>test>fix to design>analyze>test>build. Instead of needing to build multiple physical prototypes and then testing them to see if they'll work, companies can conduct testing digitally throughout the process by using Digital Prototyping, reducing the number of physical prototypes needed to validate the design. Studies show that by using Digital Prototyping to catch design problems up front, manufacturers experience fewer change orders downstream. Because the geometry in digital prototypes is highly accurate, companies can check interferences to avoid assembly issues that generate change orders in the testing and manufacturing phases of development. Companies can also perform simulations in early stages of the product development cycle, so they avoid failure modes during testing or manufacturing phases. With a Digital Prototyping approach, companies can digitally test a broader range of their product's performance. They can also test design iterations quickly to assess whether they're over- or under-designing components.
Research from the Aberdeen Group shows that manufacturers that use Digital Prototyping build half the number of physical prototypes as the average manufacturer, get to market 58 days faster than average, and experience 48 percent lower prototyping costs.
History of Digital Prototyping.
The concept of Digital Prototyping has been around for over a decade, particularly since software companies such as Autodesk, PTC, Siemens PLM (formerly UGS), and Dassault began offering computer-aided design (CAD) software capable of creating accurate 3D models.
It may even be argued that the product lifecycle management (PLM) approach was the harbinger of Digital Prototyping. PLM is an integrated, information-driven approach to a product's lifecycle, from development to disposal. A major aspect of PLM is coordinating and managing product data among all software, suppliers, and team members involved in the product's lifecycle. Companies use a collection of software tools and methods to integrate people, data, and processes to support singular steps in the product's lifecycle or to manage the product's lifecycle from beginning to end. PLM often includes product visualization to facilitate collaboration and understanding among the internal and external teams that participate in some aspect of a product's lifecycle.
While the concept of Digital Prototyping has been a longstanding goal for manufacturing companies for some time, it's only recently that Digital Prototyping has become a reality for small-to-midsize manufacturers that cannot afford to implement complex and expensive PLM solutions.
Digital Prototyping and PLM.
Large manufacturing companies rely on PLM to link otherwise unconnected, siloed activities, such as concept development, design, engineering, manufacturing, sales, and marketing. PLM is a fully integrated approach to product development that requires investments in application software, implementation, and integration with enterprise resource planning (ERP) systems, as well as end-user training and a sophisticated IT staff to manage the technology. PLM solutions are highly customized and complex to implement, often requiring a complete replacement of existing technology. Because of the high expense and IT expertise required to purchase, deploy, and run a PLM solution, many small-to-midsized manufacturers cannot implement PLM.
Digital Prototyping is a viable alternative to PLM for these small-to-midsized manufacturers. Like PLM, Digital Prototyping seeks to link otherwise unconnected, siloed activities, such as concept development, design, engineering, manufacturing, sales, and marketing. However, unlike PLM, Digital Prototyping does not support the entire product development process from conception to disposal, but rather focuses on the design-to-manufacture portion of the process. The realm of Digital Prototyping ends when the digital product and the engineering bill of materials are complete. Digital Prototyping aims to resolve many of the same issues as PLM without involving a highly customized, all-encompassing software deployment. With Digital Prototyping, a company may choose to address one need at a time, making the approach more pervasive as its business grows. Other differences between Digital Prototyping and PLM include:
Digital Prototyping Workflow.
A Digital Prototyping workflow involves using a single digital model throughout the design process to bridge the gaps that typically exist between workgroups such as industrial design, engineering, manufacturing, sales, and marketing. Product development can be broken into the following general phases at most manufacturing companies:
Conceptual Design.
The conceptual design phase involves taking customer input or market requirements and data to create a product design. In a Digital Prototyping workflow, designers work digitally, from the very first sketch, throughout the conceptual design phase. They capture their designs digitally, and then share that data with the engineering team using a common file format. The industrial design data is then incorporated into the digital prototype to ensure technical feasibility.
In a Digital Prototyping workflow, designers and their teams review digital design data via high-quality digital imagery or renderings to make informed product design decisions. Designers may create and visualize several iterations of design, changing things like materials or color schemes, before a concept is finalized.
Engineering.
During the engineering phase of the Digital Prototyping workflow, engineers create the product's 3D model (the digital prototype), integrating design data developed during the conceptual design phase. Teams also add electrical systems design data to the digital prototype while it's being developed, and evaluate how different systems interact. At this stage of the workflow, all data related to the product's development is fully integrated into the digital prototype. Working with mechanical, electrical, and industrial design data, companies engineer every last product detail in the engineering phase of the workflow. At this point, the digital prototype is a fully realistic digital model of the complete product.
Engineers test and validate the digital prototype throughout their design process to make the best possible design decisions and avoid costly mistakes. Using the digital prototype, engineers can:
By incorporating integrated calculations, stress, deflection, and motion simulations into the Digital Prototyping workflow, companies can speed development cycles by minimizing physical prototyping phases. By implementing a digital prototype of a partially or fully automated vehicle and its sensor suite into a dynamic co-simulation of traffic flow and vehicle dynamics, a novel toolchain methodology comprising virtual testing is available for the development of automated driving functions by the automotive industry.
Also during the engineering phase of the Digital Prototyping workflow, engineers create documentation required by the production team.
Manufacturing.
In a Digital Prototyping workflow, manufacturing teams are involved early in the design process. This input helps engineers and manufacturing experts work together on the digital prototype throughout the design process to ensure that the product can be produced cost effectively. Manufacturing teams can see the product exactly as it's intended, and provide input on manufacturability. Companies can perform molding simulations on digital prototypes for plastic part and injection molds to test the manufacturability of their designs, identifying potential manufacturing defects before they cut mold tooling.
Digital Prototyping also enables product teams to share detailed assembly instructions digitally with manufacturing teams. While paper assembly drawings can be confusing, 3D visualizations of digital prototypes are unambiguous. This early and clear collaboration between manufacturing and engineering teams helps minimize manufacturing problems on the shop floor.
Finally, manufacturers can use Digital Prototyping to visualize and simulate factory-floor layouts and production lines. They can check for interferences to detect potential issues such as space constraints and equipment collisions.
Customer Involvement.
Customers are involved throughout the Digital Prototyping workflow. Rather than waiting for a physical prototype to be complete, companies that use Digital Prototyping bring customers into the product development process early. They show customers realistic renderings and animations of the product's digital prototype so they'll know what the product looks like and how it will function. This early customer involvement helps companies get sign-off up front, so they don't waste time designing, engineering, and manufacturing a product that doesn't fulfill the customer's expectations.
Marketing.
Using 3D CAD data from the digital prototype, companies can create realistic visualizations, renderings, and animations to market products in print, on the web, in catalogues, or in television commercials. Without needing to produce expensive physical prototypes and conduct photo shoots, companies can create virtual photography and cinematography nearly indistinguishable from reality. One aspect of this is creating the illumination environment for the subject, an area of new development.
Realistic visualizations not only help marketing communications, but the sales process as well. Companies can respond to requests for proposals and bid on projects without building physical prototypes, using visualizations to show the potential customer what the end product will be like. In addition, visualizations can help companies bid more accurately by making it more likely that everyone has the same expectations about the end product. Companies can also use visualizations to facilitate the review process once they've secured the business. Reviewers can interact with digital prototypes in realistic environments, allowing for the validation of design decisions early in the product development process.
Connecting Data and Teams.
To support a Digital Prototyping workflow, companies use data management tools to coordinate all teams at every stage in the workflow, streamline design revisions and automate release processes for digital prototypes, and manage engineering bills of materials. These data management tools connect all workgroups to critical Digital Prototyping data.
Digital Prototyping and Sustainability.
Companies increasingly use Digital Prototyping to understand sustainability factors in new product designs, and to help meet customer requirements for sustainable products and processes. They minimize material use by assessing multiple design scenarios to determine the optimal amount and type of material required to meet product specifications. In addition, by reducing the number of physical prototypes required, manufacturers can trim down their material waste.
Digital Prototyping can also help companies reduce the carbon footprint of their products. For example, WinWinD, a company that creates innovative wind turbines, uses Digital Prototyping to optimize the energy production of wind-power turbines for varying wind conditions. Furthermore, the rich product data supplied by Digital Prototyping can help companies demonstrate conformance with the growing number of product-related environmental regulations and voluntary sustainability standards.


Magnetic pulse welding

Magnetic pulse welding (MPW) is a solid state welding process that uses magnetic forces to weld two workpieces together. The welding mechanism is most similar to that of explosion welding.
Magnetic pulse welding started in the early 1970s, when the automotive industry began to use solid state welding. The biggest advantage using magnetic pulse welding is that the formation of brittle intermetallic phases is avoided. Therefore, dissimilar metals can be welded, which cannot be effectively joined by fusion welding. With magnetic pulse welding high quality welds in similar and dissimilar metals can be made in microseconds without the need for shielding gases or welding consumables.
Process.
Magnetic pulse welding is based on a very short electromagnetic pulse (capacitors through low inductance switches into a coil. The pulsed current with a very high amplitude and frequency (500 kA and 15 kHz) produces a high-density magnetic field, which creates an eddy current in one of the work pieces. Repulsive Lorentz forces are created and a high magnetic pressure well beyond the material yield strength causing acceleration and one of the work pieces impacts onto the other part with a collision velocity up to .
During magnetic pulse welding a high plastic deformation is developed along with high shear strain and oxide disruption thanks to the jet and high temperatures near the collision zone. This leads to solid state weld due to the microstructure refinement, dislocation cells, slip bends, micro twins and local recrystallization.
Principles.
In order to get a strong weld, several conditions have to be reached:
The main difference between magnetic pulse welding and explosive welding is that the collision angle and the velocity are almost constant during the explosive welding process, while in magnetic pulse welding they continuously vary.
Numerical simulations of MPW.
Various numerical investigations were carried out to predict the interface behavior of the MPW and the in-flight behavior of the flyer to determine the collision conditions. Generally, the flyer velocity prior to the impact governs the interfacial phenomena. This is the characteristic parameter that should be known based on the process and adjustable process parameters. Although, Experimental measurements using laser velocimetry methods provide an accurate assessment of the flyer velocity, (one example of such measurement is Photon Doppler velocimetry (PDV)), numerical computation offers a better description of the flyer velocity in terms of spatial and temporal distribution. Moreover, a multi-physics computation of the MPW process take into account of the electrical current through the coil and compute the physical behavior for an electromagnetic-mechanical coupled problem. Sometime, these simulations also allow to include the thermal effect during the process. A 3D example model used for LS-DYNA simulation is also described in , and it also provides some details of the physical interactions of the process, the governing equations, the resolution procedure, and both boundary and initial conditions. The model is used to show the capability of 3D computation to predict the process behavior and particularly, the flyer kinematics and macroscopic deformation.


Evolution of management systems

This article outlines the evolution of management systems. A management system is the framework of processes and procedures used to ensure that an organization can fulfill all tasks required to achieve its objectives.
After World War II, the reigning paradigm of product-oriented mass production had reached its peak. Examples of management systems at that time are linear assembly lines, organizational hierarchies of command, product quality control and mass consumption.
Soon afterwards, the Deming-Juran process-quality teachings spearheaded a new quality orientation (later referred to as Total quality management) and propelled Japan directly to the post-war process focus (process quality control, just-in-time, continuous improvement). The US responded by a painful and prolonged product-to-process transformation, ultimately leveling the playing field again by the mid 1980s.
At the end of the 1980s, business process reengineering focused on the radical redesign of the production process through the reintegration of task, labor and knowledge. As a result, lean, flexible and streamlined production processes were created, capable of fast response and internet-based integration necessary for the upcoming phase of supply chains - business-to-business (B2B) – as well as demand chains – business-to-customer (B2C).
In the above three stages of evolution of management systems, the competitive advantage was derived almost exclusively from the internal resources of the firm. At the end of the 1980s, a radical fourth shift has occurred: the competitive advantage became increasingly derived from the external resources of the firm – through the extended networks of suppliers and customers.
Figure 1 refers to the basic scheme of production and service delivery process. It represents the traditional linear input-process-output management system. This system has been fixed and unchanging for centuries. The only change has been in terms of changing focus on individual components of the system, emphasizing different parts of this basic scheme.
Although the scheme itself (inputs → process → outputs) remains mostly unchallenged, there are some indications that this business model will undergo major restructurings in the future (in the emerging stages of evolution of management systems). It will become disaggregated and distributed, subjected to non-linear modularity and bringing forth new ways of making things and delivering services. Then it will become reintegrated again, tying together globally distributed components into a unified recycling whole.
Early stages.
All early stages are characterized by changing focus of attention within the unchanging, invariant scheme of Figure 1. The management system has typically focused on:
Final product.
The final product is a primary focus, the production process is considered secondary. Its operations and their sequences are technologically fixed or ‘given’. Product quality is ‘inspected in’, mostly at the end of the process. Statistical quality control, inventory control, cost minimization, mass production, assembly line, work specialization, hierarchies of command, mass consumption, statistical mass markets and forecasting are among the defining characteristics of this stage.
Partitioned process.
It is the high-quality process that assures the high-quality product. The main focus was on improving of process operations. Quality of the process was understood as the quality of its operations. Powerful new concepts of Total Quality Management (TQM), Continuous Improvement Process (Kaizen) and Just-In-Time (JIT) systems have characterized this stage. Although the operations were being improved, the process architecture and structural sequencing were kept intact and remained technologically ‘given’.
Integrated process.
The focus of attention shifted from operations (circles) to linkages (arrows) – thus changing the process architecture itself. The reengineering of the process, re-integrating individual components into effective, more autonomous and even self-manageable wholes, has characterized this stage. The production process became a business process and therefore subject to qualitative redesign and reengineering (BPR). Discontinuous improvement and process innovation replaced the piecemeal continuous improvement. Traditional vertical hierarchies of command have flattened out into more horizontal, process-oriented networks. Mass customization, disintermediation, knowledge management and autonomous teams have started emerging.
Extended process.
Figure 2 refers to the paradigmatic shift from internal processes expanded into the extended process – including supplier networks and alliances as well as customer self-service, mass customization and disintermediation – as the increasingly external sources of competitive advantage.
In this recently peaked stage, networks of suppliers and communities of customers have extended the internal process into a functional and competitive whole. Both internal and external sources of knowledge and competitiveness have formed new core competencies. Supply and demand chains management have emerged, in dependence on shifting CIP (Customer Intervention Point). Intranets and extranets have provided a communication medium for B2B and B2C exchanges. Quality has become bundled together with cost, speed and reliability..
Today, powerful processes of global sourcing bring forth and foster a new set of relationships with customers and suppliers. The firm starts disaggregating its production processes, transferring, leasing or selling selected pieces off to a higher-added value operator or coordinator. Any firm can be only as good as is the network of which it is a part. Consequently, the firm has disaggregated and became a network.
Distributed process.
This emerging stage represents the most radical business refocusing so far. Through the global sourcing, sections and components of the internal process are being outsourced to external providers and contractors in search of the highest added value contribution. Long-term alliances are formed and companies are transforming themselves into networks. Network cooperation is replacing corporate competition: "coopetition" emerges. The majority of companies (also the educational and training institutions) could still be the leading global players in this incessant and accelerating paradigm shifting. Globally distributed process ushers in new forms of organization, coordination and modular integration.
Different parts of the extended process are geographically distributed and often spatially remote. In Figure 3, this distribution is represented by sections OS of the process which have been outsourced to higher added-value providers.
Although the Stage 5 (Figure 3) represents the most radical business refocusing emerging so far, still rapidly emerging kernels of the next stage (Figure 4) is taking shape. The evolutionary process, driven by relentless global search for maximum added value, is clearly accelerating. Management systems paradigm or business model, after a century of relative invariance, is becoming a new dynamic source of competitive advantage. Radically distributed supply and demand chains of Stage 5 will clearly have to be coordinated and reintegrated on a global scale. Reintegration processes are proceeding under increasing environmental pressures. The search for added value, after exploring traditional global resources, is now turning towards reuse, recycling, recovery and remanufacturing as new sources of maximizing added value. Innovation in business models will become a norm.
Recycled process.
During the process of utilizing added value, the asset-recovery practices expand quickly to a majority of products and services (Dell, IBM, Xerox). New products are being designed for extended life spans and multiple profit cycles. Reverse logistics and reverse logistics management (RLM) are adding new loops to the traditionally unidirectional processes of supply chains. Old supply chains have become demand chains and now reverse value chains, demonstrating that value can be added in both directions: through the forward pass of production as well as through the backward pass of recovery and remanufacture. Concepts of easy disassembly, durability, reuse and recycling are built in into equipment design.
Figure 4 refers to closed-loop management system and it represents the Stage 6 of the evolution of management systems. The new loops in the figure are not just traditional information feedback loops, but real business processes of collection, disassembly, reprocessing and reassembly activities (operations). The conventional open-ended linear processes are being redesigned towards closure.
New loops of recycled products and materials, energy recovery and knowledge renewal are being created within global-sourcing (GS) networks. Product reuse/remanufacture relies on a high residual value which gives a good head start for added value maximization. The system becomes organizationally closed and potentially long-term sustainable or even trans-generations self-sustainable. The "openness" and customization of the product design, upgradeable products, flexible product platforms, mutability and waste-free strategies are being implemented. However, in this latest stage, new employee skills and managerial knowledge, as well as essential mass customization mindset are yet to be produced, maintained and renewed. Eliminating non-value added resources is still necessary. Integrating production system elements and work functions still needs time to evolve.
Evolutionary spiral.
Evolutionary spiral of the six management systems (SMS) are indicated in Figure 5.
It is appropriate to notice that six-management-system evolution is progressing in an accelerated fashion, the periods of stasis are getting shorter and revolutions are occurring faster. Individual management systems are beginning to overlap and their boundaries are getting blurred. An era of continuous change in business models and management systems emerges: the search for competitive advantage (one over the other) becomes relentless, strenuous and resources depleting. Cooperation networks have to merge into larger entities, reducing competition and expanding collaboration. The search for collaborative advantage (for both jointly) will become the new mode of economic behavior.


Shift kit

A shift kit is a set of components for automobiles designed to improve how well the car shifts between gears. Kits are made for both automatic and manual transmissions.
Goals.
Shifts may be optimized for different goals. Some drivers want slow, smooth shifts for comfort, while others want quick shifts for performance or towing.
Towing considerations.
During a shift, power is lost in the clutch (for automatic transmissions the clutches are usually internal) due to clutch slip and the difference between the current and final output shaft speeds. This makes a quick shift more desirable when towing, to reduce clutch wear and heat developed in the transmission. Balancing this, too quick a shift increases peak mechanical loads on the transmission, engine and drive train; an instant shift would cause impact loads and lead to early mechanical failure, as well as an unpleasant driving experience.
Manual transmission kit.
For manual transmission equipped cars, it is a component that replaces the stock gear selector (shifter). A shift kit usually shortens the throws of selecting a gear (also known as a short throw shift or short shifter), therefore allowing a driver to reduce the shift time and change gears more efficiently.
Automatic transmission kit.
An automatic transmission's main focus is smooth shifting between gears. To accomplish this it often goes into two gears at once while shifting up, which is known as a shift overlap. In these cars, it is a kit that can reduce or eliminate the shift overlap. It will also reduce wear because the transmission won't be trying to drive in two gears at once.
History.
The term "Shift Kit" is a registered trademark of the company "TransGo" which originated the development of automatic transmission valve body improvement and upgrade components such as springs, valves, and instructional materials to improve the shift characteristics and durability of automatic transmissions.


Rake angle

In machining, the rake angle is a parameter used in various cutting processes, describing the angle of the cutting face relative to the workpiece. There are three types of rake angles: "positive", "zero" or "neutral", and "negative".
Positive rake angles generally:
Negative rake angles generally:
Zero rake angles:
Recommended rake angles.
Recommended rake angles can vary depending on the material being cut, tool material, depth of cut, cutting speed, machine, setup and process. This table summarizes recommended rake angles for: single-point turning on a lathe, drilling, milling, and sawing.


Weihenstephan Standards

The Weihenstephan Standards ("Weihenstephaner Standard" in German), also referred to as "WS" in shorthand, are communication interfaces for machine data acquisition.
The standards were developed by a working group of machine manufacturers, plant suppliers, IT system vendors and technologists, under the guidance of the Technical University of Munich (TUM) at the Faculty of Food Packaging Technology in Weihenstephan, Germany.
Weihenstephan libraries have been developed for production data acquisition in bottling and packaging plants (WS Pack), food industry plants (WS Food), in the bakery industry (WS Bake), and for processes within the brewing industry (WS Brew). These libraries are used to connect the plants industrial equipment within the production processes to higher-level management and control systems such as data acquisition systems (SCADA) or Manufacturing Execution Systems (MES). In the Weihenstephan Standards, the physical interface specification, specification of the interface content, recommendations for data evaluation and reporting are defined.
The Weihenstephan Standards 2000 comprise the guidelines for standard BDE specifications for bottling plants; the Weihenstephan Standards 2005 describe the interfaces and data provision for bottling and packaging plants in the beverage industry.
Description.
The Weihenstephan standards are located in the automation pyramid as a link between the production management level and the process control level. The standards allow an MES to exchange data with the controls of various machines and thus support the MES' operation. To help manage the data the standards provide:
In addition, industry-specific reports and evaluation examples are available in the Weihenstephan Standards.
See also.
Brewmaxx


Nibbler

A nibbler, or nibblers, is a tool for cutting sheet metal with minimal distortion. They may be used for nibbling. One type operates much like a punch and die, with a blade that moves in a linear fashion against a fixed die, removing small bits of metal and leaving a kerf approximately 6 mm wide. Another type operates similar to tin snips, but shears the sheet along two parallel tracks 3–6 mm apart, rolling up the waste in a tight spiral as it cuts. Nibblers may be manual (hand operated) or powered.
Power nibblers are often powered by compressed air, though electrical types also exist. A common DIY nibbler tool is an electric drill attachment, which converts the rotary motion of the drill into a reciprocating motion of the jaw.


Forge welding

Forge welding (FOW), also called fire welding, is a solid-state welding process that joins two pieces of metal by heating them to a high temperature and then hammering them together. It may also consist of heating and forcing the metals together with presses or other means, creating enough pressure to cause plastic deformation at the weld surfaces. The process, although challenging, has been a method of joining metals used since ancient times and is a staple of traditional blacksmithing. Forge welding is versatile, being able to join a host of similar and dissimilar metals. With the invention of electrical welding and gas welding methods during the Industrial Revolution, manual forge-welding has been largely replaced, although automated forge-welding is a common manufacturing process.
Introduction.
Forge welding is a process of joining metals by heating them beyond a certain threshold and forcing them together with enough pressure to cause deformation of the weld surfaces, creating a metallic bond between the atoms of the metals. The pressure required varies, depending on the temperature, strength, and hardness of the alloy. Forge welding is the oldest welding technique, and has been used since ancient times.
Welding processes can generally be grouped into two categories: fusion and diffusion welding. Fusion welding involves localized melting of the metals at the weld interfaces, and is common in electric or gas welding techniques. This requires temperatures much higher than the melting point of the metal in order to cause localized melting before the heat can thermally conduct away from the weld, and often a filler metal is used to keep the weld from segregating due to the high surface tension. Diffusion welding consists of joining the metals without melting them, welding the surfaces together while in the solid state.
In diffusion welding, the heat source is often lower than the melting point of the metal, allowing more even heat-distribution thus reducing thermal stresses at the weld. In this method a filler metal is typically not used, but the weld occurs directly between the metals at the weld interface. This includes methods such as cold welding, explosion welding, and forge welding. Unlike other diffusion methods, in forge welding the metals are heated to a high temperature before forcing them together, usually resulting in greater plasticity at the weld surfaces. This generally makes forge welding more versatile than cold-diffusion techniques, which are usually performed on soft metals like copper or aluminum.
In forge welding, the entire welding areas are heated evenly. Forge welding can be used for a much wider range of harder metals and alloys, like steel and titanium.
History.
The history of joining metals goes back to the Bronze Age, where bronzes of different hardness were often joined by casting-in. This method consisted of placing a solid part into a molten metal contained in a mold and allowing it to solidify without actually melting both metals, such as the blade of a sword into a handle or the tang of an arrowhead into the tip. Brazing and soldering were also common during the Bronze Age.
The act of welding (joining two solid parts through diffusion) began with iron. The first welding process was forge welding, which started when humans learned to smelt iron from iron ore; most likely in Anatolia (Turkey) around 1800 BC. Ancient people could not create temperatures high enough to melt iron fully, so the bloomery process that was used for smelting iron produced a lump (bloom) of iron grains sintered together with small amounts of slag and other impurities, referred to as sponge iron because of its porosity.
After smelting, the sponge iron needed to be heated above the welding temperature and hammered, or "wrought." This squeezed out air pockets and melted slag, bringing the iron grains into close contact to form a solid block (billet).
Many items made of wrought iron have been found by archeologists, that show evidence of forge welding, which date from before 1000 BC. Because iron was typically made in small amounts, any large object, such as the Delhi Pillar, needed to be forge welded out of smaller billets.
Forge welding grew from a trial-and-error method, becoming more refined over the centuries. Due to the poor quality of ancient metals, it was commonly employed in making composite steels, by joining high-carbon steels, that would resist deformation but break easily, with low-carbon steels, which resist fracture but bend too easily, creating an object with greater toughness and strength than could be produced with a single alloy. This method of pattern welding first appeared around 700 BC, and was primarily used for making weapons such as swords; the most widely known examples being Damascene, Japanese and Merovingian. This process was also common in the manufacture of tools, from wrought-iron plows with steel edges to iron chisels with steel cutting surfaces.
Materials.
Many metals can be forge welded, with the most common being both high and low-carbon steels. Iron and even some hypoeutectic cast-irons can be forge welded. Some aluminum alloys can also be forge welded. Metals such as copper, bronze and brass do not forge weld readily. Although it is possible to forge weld copper-based alloys, it is often with great difficulty due to copper's tendency to absorb oxygen during the heating. Copper and its alloys are usually better joined with cold welding, explosion welding, or other pressure-welding techniques. With iron or steel, the presence of even small amounts of copper severely reduces the alloy's ability to forge weld.
Titanium alloys are commonly forge welded. Because of titanium's tendency to absorb oxygen when molten, the solid-state, diffusion bond of a forge weld is often stronger than a fusion weld in which the metal is liquefied.
Forge welding between similar materials is caused by solid-state diffusion. This results in a weld that consists of only the welded materials without any fillers or bridging materials. Forge welding between dissimilar materials is caused by the formation of a lower melting temperature eutectic between the materials. Due to this the weld is often stronger than the individual metals.
Processes.
The most well-known and oldest forge-welding process is the manual-hammering method. Manual hammering is done by heating the metal to the proper temperature, coating with flux, overlapping the weld surfaces, and then striking the joint repeatedly with a hand-held hammer. The joint is often formed to allow space for the flux to flow out, by beveling or rounding the surfaces slightly, and hammered in a successively outward fashion to squeeze the flux out. The hammer blows are typically not as hard as those used for shaping, preventing the flux from being blasted out of the joint at the first blow.
When mechanical hammers were developed, forge welding could be accomplished by heating the metal, and then placing it between the mechanized hammer and the anvil. Originally powered by waterwheels, modern mechanical-hammers can also be operated by compressed air, electricity, steam, gas engines, and many other ways. Another method is forge welding with a die, whereby the pieces of metal are heated and then forced into a die which both provides the pressure for the weld and keeps the joint at the finished shape. Roll welding is another forge welding process, where the heated metals are overlapped and passed through rollers at high pressures to create the weld.
Modern forge-welding is often automated, using computers, machines, and sophisticated hydraulic presses to produce a variety of products from a number of various alloys. For example, steel pipe is often forge-welded during the manufacturing process. Flat stock is heated and fed through specially-shaped rollers that both form the steel into a tube and simultaneously provide the pressure to weld the edges into a continuous seam.
Diffusion bonding is a common method for forge welding titanium alloys in the aerospace industry. In this process the metal is heated while in a press or die. Beyond a specific critical-temperature, which varies depending on the alloy, the impurities burn out and the surfaces are forced together.
Other methods include flash welding and percussion welding. These are resistance forge-welding techniques where the press or die is electrified, passing high current through the alloy to create the heat for the weld. Shielded active-gas forge-welding is a process of forge welding in an oxygen-reactive environment, to burn out oxides, using hydrogen gas and induction heating.
Temperature.
Iron, different steels, and even cast-iron can be welded to each other, provided that their carbon content is close enough that the welding ranges overlap. Pure iron can be welded when nearly white hot; between and . Steel with a carbon content of 2.0% can be welded when orangish-yellow, between and . Common steel, between 0.2 and 0.8% carbon, is typically welded at a bright yellow heat.
A primary requirement for forge welding is that both weld surfaces need to be heated to the same temperature and welded before they cool too much. When steel reaches the proper temperature, it begins to weld very readily, so a thin rod or nail heated to the same temperature will tend to stick at first contact, requiring it to be bent or twisted loose.
Care must be taken to avoid overheating the metal to the point that it gives off sparks from rapid oxidation (burning), or else the weld will be poor and brittle.
Decarburization.
When steel is heated to an austenizing temperature, the carbon begins to diffuse through the iron. The higher the temperature; the greater the rate of diffusion. At such high temperatures, carbon readily combines with oxygen to form carbon dioxide, so the carbon can easily diffuse out of the steel and into the surrounding air. By the end of a blacksmithing job, the steel will be of a lower carbon content than it was prior to heating. Therefore, most blacksmithing operations are done as quickly as possible to reduce decarburization, preventing the steel from becoming too soft.
To produce the right amount of hardness in the finished product, the smith generally begins with steel that has a carbon content that is higher than desired. In ancient times, forging often began with steel that had a carbon content much too high for normal use. Most ancient forge-welding began with hypereutectoid steel, containing a carbon content sometimes well above 1.0%. Hypereutectoid steels are typically too brittle to be useful in a finished product, but by the end of forging the steel typically had a high carbon-content ranging from 0.8% (eutectoid tool-steel) to 0.5% (hypoeutectoid spring-steel).
Applications.
Forge welding has been used throughout its history for making most any items out of steel and iron. It has been used in everything from the manufacture of tools, farming implements, and cookware to the manufacture of fences, gates, and prison cells. In the early Industrial Revolution, it was commonly used in the manufacture of boilers and pressure vessels, until the introduction of fusion-welding. It was commonly used through the Middle Ages for producing armor and weapons.
One of the most famous applications of forge welding involves the production of pattern-welded blades. During this process a smith repeatedly draws out a billet of steel, folds it back and welds it upon itself. Another application was the manufacture of shotgun barrels. Metal wire was spooled onto a mandrel, and then forged into a barrel that was thin, uniform, and strong. In some cases the forge-welded objects are acid-etched to expose the underlying pattern of metal, which is unique to each item and provides aesthetic appeal.
Despite its diversity, forge welding had many limitations. A primary limitation was the size of objects that could be forge welded. Larger objects required a bigger heat source, and size reduced the ability to manually weld it together before it cooled too much. Welding large items like steel plate or girders was typically not possible, or at least highly impractical, until the invention of fusion welding, requiring them to be riveted instead. In some cases, fusion welding produced a much stronger weld, such as in the construction of boilers.
Flux.
Forge welding requires the weld surfaces to be extremely clean or the metal will not join properly, if at all. Oxides tend to form on the surface while impurities like phosphorus and sulfur tend to migrate to the surface. Often a flux is used to keep the welding surfaces from oxidizing, which would produce a poor quality weld, and to extract other impurities from the metal. The flux mixes with the oxides that form and lowers the melting temperature and the viscosity of the oxides. This enables the oxides to flow out of the joint when the two pieces are beaten together. A simple flux can be made from borax, sometimes with the addition of powdered iron-filings.
The oldest flux used for forge welding was fine silica sand. The iron or steel would be heated in a reducing environment within the coals of the forge. Devoid of oxygen, the metal forms a layer of iron-oxide called wustite on its surface. When the metal is hot enough, but below the welding temperature, the smith sprinkles some sand onto the metal. The silicon in the sand reacts with the wustite to form fayalite, which melts just below the welding temperature. This produced a very effective flux which helped to make a strong weld.
Early examples of flux used different combinations and various amounts of iron fillings, borax, sal ammoniac, balsam of copaiba, cyanide of potash, and soda phosphate. The 1920 edition of "Scientific American book of facts and formulae" indicates a frequently offered trade secret as using copperas, saltpeter, common salt, black oxide of manganese, prussiate of potash, and "nice welding sand" (silicate).


Electrical discharge machining

Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a metal
fabrication process whereby a desired shape is obtained by using electrical discharges (sparks). Material is removed from the work piece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the or , while the other is called the workpiece-electrode, or . The process depends upon the tool and work piece not making physical contact.
When the voltage between the two electrodes is increased, the intensity of the electric field in the volume between the electrodes becomes greater, causing dielectric break down of the liquid, and produces an electric arc. As a result, material is removed from the electrodes. Once the current stops (or is stopped, depending on the type of generator), new liquid dielectric is conveyed into the inter-electrode volume, enabling the solid particles (debris) to be carried away and the insulating properties of the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is commonly referred to as . After a current flow, the voltage between the electrodes is restored to what it was before the breakdown, so that a new liquid dielectric breakdown can occur to repeat the cycle.
History.
The erosive effect of electrical discharges was first noted in 1770 by English physicist Joseph Priestley.
Die-sink EDM.
Two Soviet scientists, B. R. Lazarenko and N. I. Lazarenko, were tasked in 1943 to investigate ways of preventing the erosion of tungsten electrical contacts due to sparking. They failed in this task but found that the erosion was more precisely controlled if the electrodes were immersed in a dielectric fluid. This led them to invent an EDM machine used for working difficult-to-machine materials such as tungsten. The Lazarenkos' machine is known as an R-C-type machine, after the resistor–capacitor circuit (RC circuit) used to charge the electrodes.
Simultaneously but independently, an American team, Harold Stark, Victor Harding, and Jack Beaver, developed an EDM machine for removing broken drills and taps from aluminium castings. Initially constructing their machines from under-powered electric-etching tools, they were not very successful. But more powerful sparking units, combined with automatic spark repetition and fluid replacement with an electromagnetic interrupter arrangement produced practical machines. Stark, Harding, and Beaver's machines were able to produce 60 sparks per second. Later machines based on their design used vacuum tube circuits that were able to produce thousands of sparks per second, significantly increasing the speed of cutting.
Wire-cut EDM.
The wire-cut type of machine arose in the 1960s for making tools (dies) from hardened steel. The tool electrode in wire EDM is simply a wire. To avoid the erosion of the wire causing it to break, the wire is wound between two spools so that the active part of the wire is constantly changing. The earliest numerical controlled (NC) machines were conversions of punched-tape vertical milling machines. The first commercially available NC machine built as a wire-cut EDM machine was manufactured in the USSR in 1967. Machines that could optically follow lines on a master drawing were developed by David H. Dulebohn's group in the 1960s at Andrew Engineering Company for milling and grinding machines. Master drawings were later produced by computer numerical controlled (CNC) plotters for greater accuracy. A wire-cut EDM machine using the CNC drawing plotter and optical line follower techniques was produced in 1974. Dulebohn later used the same plotter CNC program to directly control the EDM machine, and the first CNC EDM machine was produced in 1976.
Commercial wire EDM capability and use has advanced substantially during recent decades. Feed rates have increased and surface finish can be finely controlled.
Generalities.
Electrical discharge machining is a machining method primarily used for hard metals or those that would be very difficult to machine with traditional techniques. EDM typically works with materials that are electrically conductive, although methods have also been proposed for using EDM to machine insulating ceramics. EDM can cut intricate contours or cavities in pre-hardened steel without the need for heat treatment to soften and re-harden them. This method can be used with any other metal or metal alloy such as titanium, hastelloy, kovar, and inconel. Also, applications of this process to shape polycrystalline diamond tools have been reported.
EDM is often included in the "non-traditional" or "non-conventional" group of machining methods together with processes such as electrochemical machining (ECM), water jet cutting (WJ, AWJ), laser cutting and opposite to the "conventional" group (turning, milling, grinding, drilling and any other process whose material removal mechanism is essentially based on mechanical forces).
Ideally, EDM can be seen as a series of breakdown and restoration of the liquid dielectric in-between the electrodes. However, caution should be exerted in considering such a statement because it is an idealized model of the process, introduced to describe the fundamental ideas underlying the process. Yet, any practical application involves many aspects that may also need to be considered. For instance, the removal of the debris from the inter-electrode volume is likely to be always partial. Thus the electrical properties of the dielectric in the inter-electrodes volume can be different from their nominal values and can even vary with time. The inter-electrode distance, often also referred to as spark-gap, is the result of the control algorithms of the specific machine used. The control of such a distance appears logically to be central to this process. Also, not all of the current between the dielectric is of the ideal type described above: the spark-gap can be short-circuited by the debris. The control system of the electrode may fail to react quickly enough to prevent the two electrodes (tool and workpiece) from coming into contact, with a consequent short circuit. This is unwanted because a short circuit contributes to material removal differently from the ideal case. The flushing action can be inadequate to restore the insulating properties of the dielectric so that the current always happens in the point of the inter-electrode volume (this is referred to as arcing), with a consequent unwanted change of shape (damage) of the tool-electrode and workpiece. Ultimately, a description of this process in a suitable way for the specific purpose at hand is what makes the EDM area such a rich field for further investigation and research.
To obtain a specific geometry, the EDM tool is guided along the desired path very close to the work; ideally it should not touch the workpiece, although in reality this may happen due to the performance of the specific motion control in use. In this way, a large number of current discharges (colloquially also called sparks) happen, each contributing to the removal of material from both tool and workpiece, where small craters are formed. The size of the craters is a function of the technological parameters set for the specific job at hand. They can be with typical dimensions ranging from the nanoscale (in micro-EDM operations) to some hundreds of micrometers in roughing conditions.
The presence of these small craters on the tool results in the gradual erosion of the electrode. This erosion of the tool-electrode is also referred to as wear. Strategies are needed to counteract the detrimental effect of the wear on the geometry of the workpiece. One possibility is that of continuously replacing the tool-electrode during a machining operation. This is what happens if a continuously replaced wire is used as electrode. In this case, the correspondent EDM process is also called wire EDM. The tool-electrode can also be used in such a way that only a small portion of it is actually engaged in the machining process and this portion is changed on a regular basis. This is, for instance, the case when using a rotating disk as a tool-electrode. The corresponding process is often also referred to as EDM grinding.
A further strategy consists in using a set of electrodes with different sizes and shapes during the same EDM operation. This is often referred to as multiple electrode strategy, and is most common when the tool electrode replicates in negative the wanted shape and is advanced towards the blank along a single direction, usually the vertical direction (i.e. z-axis). This resembles the sink of the tool into the dielectric liquid in which the workpiece is immersed, so, not surprisingly, it is often referred to as die-sinking EDM (also called conventional EDM and ram EDM). The corresponding machines are often called sinker EDM. Usually, the electrodes of this type have quite complex forms. If the final geometry is obtained using a usually simple-shaped electrode which is moved along several directions and is possibly also subject to rotations, often the term EDM milling is used.
In any case, the severity of the wear is strictly dependent on the technological parameters used in the operation (for instance: polarity, maximum current, open circuit voltage). For example, in micro-EDM, also known as μ-EDM, these parameters are usually set at values which generates severe wear. Therefore, wear is a major problem in that area.
The problem of wear to graphite electrodes is being addressed. In one approach, a digital generator, controllable within milliseconds, reverses polarity as electro-erosion takes place. That produces an effect similar to electroplating that continuously deposits the eroded graphite back on the electrode. In another method, a so-called "Zero Wear" circuit reduces how often the discharge starts and stops, keeping it on for as long a time as possible.
Definition of the technological parameters.
Difficulties have been encountered in the definition of the technological parameters that drive the process.
Two broad categories of generators, also known as power supplies, are in use on EDM machines commercially available: the group based on RC circuits and the group based on transistor controlled pulses.
In both categories, the primary parameters at setup are the current and frequency delivered. In RC circuits, however, little control is expected over the time duration of the discharge, which is likely to depend on the actual spark-gap conditions (size and pollution) at the moment of the discharge. Also, the open circuit voltage (i.e. the voltage between the electrodes when the dielectric is not yet broken) can be identified as steady state voltage of the RC circuit.
In generators based on transistor control, the user is usually able to deliver a train of pulses of voltage to the electrodes. Each pulse can be controlled in shape, for instance, quasi-rectangular. In particular, the time between two consecutive pulses and the duration of each pulse can be set. The amplitude of each pulse constitutes the open circuit voltage. Thus, the maximum duration of discharge is equal to the duration of a pulse of voltage in the train. Two pulses of current are then expected not to occur for a duration equal or larger than the time interval between two consecutive pulses of voltage.
The maximum current during a discharge that the generator delivers can also be controlled. Because other sorts of generators may also be used by different machine builders, the parameters that may actually be set on a particular machine will depend on the generator manufacturer. The details of the generators and control systems on their machines are not always easily available to their user. This is a barrier to describing unequivocally the technological parameters of the EDM process. Moreover, the parameters affecting the phenomena occurring between tool and electrode are also related to the controller of the motion of the electrodes.
A framework to define and measure the electrical parameters during an EDM operation directly on inter-electrode volume with an oscilloscope external to the machine has been recently proposed by Ferri "et al." These authors conducted their research in the field of μ-EDM, but the same approach can be used in any EDM operation. This would enable the user to estimate directly the electrical parameters that affect their operations without relying upon machine manufacturer's claims. When machining different materials in the same setup conditions, the actual electrical parameters of the process are significantly different.
Material removal mechanism.
The first serious attempt at providing a physical explanation of the material removal during electric discharge machining is perhaps that of Van Dijck. Van Dijck presented a thermal model together with a computational simulation to explain the phenomena between the electrodes during electric discharge machining. However, as Van Dijck himself admitted in his study, the number of assumptions made to overcome the lack of experimental data at that time was quite significant.
Further models of what occurs during electric discharge machining in terms of heat transfer were developed in the late eighties and early nineties. It resulted in three scholarly papers: the first presenting a thermal model of material removal on the cathode, the second presenting a thermal model for the erosion occurring on the anode and the third introducing a model describing the plasma channel formed during the passage of the discharge current through the dielectric liquid. Validation of these models is supported by experimental data provided by AGIE.
These models give the most authoritative support for the claim that EDM is a thermal process, removing material from the two electrodes because of melting or vaporization, along with pressure dynamics established in the spark-gap by the collapsing of the plasma channel. However, for small discharge energies the models are inadequate to explain the experimental data. All these models hinge on a number of assumptions from such disparate research areas as submarine explosions, discharges in gases, and failure of transformers, so it is not surprising that alternative models have been proposed more recently in the literature trying to explain the EDM process.
Among these, the model from Singh and Ghosh reconnects the removal of material from the electrode to the presence of an electrical force on the surface of the electrode that could mechanically remove material and create the craters. This would be possible because the material on the surface has altered mechanical properties due to an increased temperature caused by the passage of electric current. The authors' simulations showed how they might explain EDM better than a thermal model (melting or evaporation), especially for small discharge energies, which are typically used in μ-EDM and in finishing operations.
Given the many available models, it appears that the material removal mechanism in EDM is not yet well understood and that further investigation is necessary to clarify it, especially considering the lack of experimental scientific evidence to build and validate the current EDM models. This explains an increased current research effort in related experimental techniques.
In this conclusion, there are following major factors are achieved during machining operations:
Types.
Sinker EDM.
Sinker EDM, also called ram EDM, cavity type EDM or volume EDM, consists of an electrode and workpiece submerged in an insulating liquid such as, more typically, oil or, less frequently, other dielectric fluids. The electrode and workpiece are connected to a suitable power supply. The power supply generates an electrical potential between the two parts. As the electrode approaches the workpiece, dielectric breakdown occurs in the fluid, forming a plasma channel, and a small spark jumps.
These sparks usually strike one at a time, because it is very unlikely that different locations in the inter-electrode space have the identical local electrical characteristics which would enable a spark to occur simultaneously in all such locations. These sparks happen in huge numbers at seemingly random locations between the electrode and the workpiece. As the base metal is eroded, and the spark gap subsequently increased, the electrode is lowered automatically by the machine so that the process can continue uninterrupted. Several hundred thousand sparks occur per second, with the actual duty cycle carefully controlled by the setup parameters. These controlling cycles are sometimes known as "on time" and "off time", which are more formally defined in the literature.
The on time setting determines the length or duration of the spark. Hence, a longer on time produces a deeper cavity from each spark, creating a rougher finish on the workpiece. The reverse is true for a shorter on time. Off time is the period of time between sparks. Although not directly affecting the machining of the part, the off time allows the flushing of dielectric fluid through a nozzle to clean out the eroded debris. Insufficient debris removal can cause repeated strikes in the same location which can lead to a short circuit. Modern controllers monitor the characteristics of the arcs and can alter parameters in microseconds to compensate. The typical part geometry is a complex 3D shape, often with small or odd shaped angles. Vertical, orbital, vectorial, directional, helical, conical, rotational, spin and indexing machining cycles are also used.
Wire EDM.
In "wire electrical discharge machining" (WEDM), also known as "wire-cut EDM" and "wire cutting", a thin single-strand metal wire, usually brass, is fed through the workpiece, submerged in a tank of dielectric fluid, typically deionized water. Wire-cut EDM is typically used to cut plates as thick as 300mm and to make punches, tools, and dies from hard metals that are difficult to machine with other methods.
The wire, which is constantly fed from a spool, is held between upper and lower diamond guides which is centered in a water nozzle head. The guides, usually CNC-controlled, move in the "x"–"y" plane. On most machines, the upper guide can also move independently in the "z"–"u"–"v" axis, giving rise to the ability to cut tapered and transitioning shapes (circle on the bottom, square at the top for example). The upper guide can control axis movements in the GCode standard, "x"–"y"–"u"–"v"–"i"–"j"–"k"–"l"–. This allows the wire-cut EDM to be programmed to cut very intricate and delicate shapes.
The upper and lower diamond guides are usually accurate to , and can have a cutting path or "kerf" as small as using Ø wire, though the average cutting kerf that achieves the best economic cost and machining time is using Ø brass wire. The reason that the cutting width is greater than the width of the wire is because sparking occurs from the sides of the wire to the work piece, causing erosion. This "overcut" is necessary, for many applications it is adequately predictable and therefore can be compensated for (for instance in micro-EDM this is not often the case). Spools of wire are long — an 8 kg spool of 0.25 mm wire is just over 19 kilometers in length. Wire diameter can be as small as and the geometry precision is not far from ± .
The wire-cut process uses water as its dielectric fluid, controlling its resistivity and other electrical properties with filters and PID controlled de-ionizer units. The water flushes the cut debris away from the cutting zone. Flushing is an important factor in determining the maximum feed rate for a given material thickness.
Along with tighter tolerances, multi axis EDM wire-cutting machining centers have added features such as multi heads for cutting two parts at the same time, controls for preventing wire breakage, automatic self-threading features in case of wire breakage, and programmable machining strategies to optimize the operation.
Wire-cutting EDM is commonly used when low residual stresses are desired, because it does not require high cutting forces for removal of material. If the energy/power per pulse is relatively low (as in finishing operations), little change in the mechanical properties of a material is expected due to these low residual stresses, although material that hasn't been stress-relieved can distort in the machining process.
The work piece may undergo a significant thermal cycle, its severity depending on the technological parameters used. Such thermal cycles may cause formation of a recast layer on the part and residual tensile stresses on the work piece. If machining takes place after heat treatment, dimensional accuracy will not be affected by heat treat distortion.
Fast hole drilling EDM.
Fast hole drilling EDM was designed for producing fast, accurate, small, and deep holes. It is conceptually akin to sinker EDM but the electrode is a rotating tube conveying a pressurized jet of dielectric fluid. It can make a hole an inch deep in about a minute and is a good way to machine holes in materials too hard for twist-drill machining. This EDM drilling type is used largely in the aerospace industry, producing cooling holes into aero blades and other components. It is also used to drill holes in industrial gas turbine blades, in molds and dies, and in bearings.
Applications.
Prototype production.
The EDM process is most widely used by the mold-making, tool, and die industries, but is becoming a common method of making prototype and production parts, especially in the aerospace, automobile and electronics industries in which production quantities are relatively low. In sinker EDM, a graphite, copper tungsten, or pure copper electrode is machined into the desired (negative) shape and fed into the workpiece on the end of a vertical ram.
Coinage die making.
For the creation of dies for producing jewelry and badges, or blanking and piercing (through use of a pancake die) by the coinage (stamping) process, the positive master may be made from sterling silver, since (with appropriate machine settings) the master is significantly eroded and is used only once. The resultant negative die is then hardened and used in a drop hammer to produce stamped flats from cutout sheet blanks of bronze, silver, or low proof gold alloy. For badges these flats may be further shaped to a curved surface by another die. This type of EDM is usually performed submerged in an oil-based dielectric. The finished object may be further refined by hard (glass) or soft (paint) enameling, or electroplated with pure gold or nickel. Softer materials such as silver may be hand engraved as a refinement.
Small hole drilling.
Small hole drilling EDM is used in a variety of applications.
On wire-cut EDM machines, small hole drilling EDM is used to make a through hole in a workpiece through which to thread the wire for the wire-cut EDM operation. A separate EDM head specifically for small hole drilling is mounted on a wire-cut machine and allows large hardened plates to have finished parts eroded from them as needed and without pre-drilling.
Small hole EDM is used to drill rows of holes into the leading and trailing edges of turbine blades used in jet engines. Gas flow through these small holes allows the engines to use higher temperatures than otherwise possible. The high-temperature, very hard, single crystal alloys employed in these blades makes conventional machining of these holes with high aspect ratio extremely difficult, if not impossible.
Small hole EDM is also used to create microscopic orifices for fuel system components, spinnerets for synthetic fibers such as rayon, and other applications.
There are also stand-alone small hole drilling EDM machines with an "x"–"y" axis also known as a super drill or "hole popper" that can machine blind or through holes. EDM drills bore holes with a long brass or copper tube electrode that rotates in a chuck with a constant flow of distilled or deionized water flowing through the electrode as a flushing agent and dielectric. The electrode tubes operate like the wire in wire-cut EDM machines, having a spark gap and wear rate. Some small-hole drilling EDMs are able to drill through 100 mm of soft or hardened steel in less than 10 seconds, averaging 50% to 80% wear rate. Holes of 0.3 mm to 6.1 mm can be achieved in this drilling operation. Brass electrodes are easier to machine but are not recommended for wire-cut operations due to eroded brass particles causing "brass on brass" wire breakage, therefore copper is recommended.
Metal disintegration machining.
Several manufacturers produce EDM machines for the specific purpose of removing broken cutting tools and fasteners from work pieces. In this application, the process is termed "metal disintegration machining" or MDM. The metal disintegration process removes only the center of the broken tool or fastener, leaving the hole intact and allowing a part to be reclaimed.
Closed loop manufacturing.
Closed loop manufacturing can improve the accuracy and reduce the tool costs
Advantages and disadvantages.
EDM is often compared to Electrochemical Machining.
Advantages of EDM include:
Disadvantages of EDM include:


Four-slide

A four-slide, also known as a multislide, multi-slide, or four-way, is a metalworking machine tool used in the high-volume manufacture of small stamped components from bar or wire stock. The press is most simply described as a horizontal stamping press that uses cams to control tools. The machine is used for progressive or transfer stamping operations.
Design.
A four-slide is quite different from most other presses. The key of the machine is its moving slides that have tools attached, which strike the workpiece together or in sequence to form it. These slides are driven by four shafts that outline the machine. The shafts are connected by bevel gears so that one shaft is driven by an electric motor, and then that shaft's motion drives the other three shafts. Each shaft then has cams which drive the slides, usually of a split-type. This shafting arrangement allows the workpiece to be worked for four sides, which makes this machine extremely versatile. A hole near the center of the machine is provided to expel the completed workpiece.
Advantages and disadvantages.
The greatest advantage of the four-slide machine is its ability to complete all of the operations required to form the workpiece from start to finish. Moreover, it can handle certain parts that transfer or progressive dies cannot, because it can manipulate from four axes. Due to this flexibility it reduces the cost of the finished part because it requires less machines, setups, and handling. Also, because only one machine is required, less space is required for any given workpiece. As compared to standard stamping presses the tooling is usually inexpensive, due to the simplicity of the tools. A four-slide can usually produce 20,000 to 70,000 finished parts per 16-hour shift, depending on the number of operations per part; this speed usually results in a lower cost per part.
The biggest disadvantage is its size constraints. The largest machines can handle stock up to wide, long, and thick. For wires the limit is . Other limits are the travel on the slides, which maxes out at , and the throw of the forming cams, which is between . The machine is also limited to only shearing and bending operations. Extrusion and upsetting operations are impractical because it hinders the movement of the workpiece to the next station. Drawing and stretching require too much tonnage and the mechanisms required for the operations are space prohibitive. Finally, this machine is only feasible to use on high volume parts because of the long lead time required to set up the tooling.
Materials.
The material stock used in four-slides is usually limited by its formability and not the machine capabilities. Usually the forming characteristics and bending radii are the most limiting factors. The most commonly used materials are:
Use.
Items that are commonly produced on this machine include: automotive stampings, hinges, links, clips, and razor blades.


Integration platform

An integration platform is software which integrates different applications and services. It differentiates itself from the enterprise application integration which has a focus on supply chain management. It uses the idea of system integration to create an environment for engineers.
Integration platforms can be built from components, purchased as a pre-built product ready for installation or procured from an integration Platform as a Service (iPaaS) company.
Overview.
An integration platform tries to create an environment in which engineers can:
Common components of integration platform.
Integration platform typically contains a set of functional components, such as
Differentiation.
An integration platform has a focus to be designed by and helpful to engineers. It has no intention to map business processes or integrate tools for supply chain management. Therefore it is not related to those systems.


Horizontal boring machine

A horizontal boring machine or horizontal boring mill is a machine tool which bores holes in a horizontal direction. There are three main types — table, planer and floor. The table type is the most common and, as it is the most versatile, it is also known as the universal type.
A horizontal boring machine has its work spindle parallel to the ground and work table. Typically there are three linear axes in which the tool head and part move. Convention dictates that the main axis that drives the part towards the work spindle is the Z axis, with a cross-traversing X axis and a vertically traversing Y axis. The work spindle is referred to as the C axis and, if a rotary table is incorporated, its centre line is the B axis.
Horizontal boring machines are often heavy-duty industrial machines used for roughing out large components, but there are high-precision models too. Modern machines use advanced computer numerical control (CNC) systems and techniques. Charles DeVlieg entered the Machine Tool Hall of Fame for his work upon a highly precise model, which he called a JIGMIL. The accuracy of this machine convinced the United States Air Force to accept John Parson's idea for numerically controlled machine tools.


Siliconware Precision Industries

Siliconware Precision Industries (NASDAQ:SPIL) was set up on May 17, 1984 and now is based in Taichung, Taiwan. The company focuses on semiconductor packaging and testing services for PC, communications, consumer integrated circuits markets. These services are provided to protect semiconductor chips, better integrating into electronic systems, and improving the dissipation of heat.
History.
Siliconware Precision Industries as founded in 1984. In 2000 the company became a public company in NASDAQ and in the same year, SPIL merged with Siliconware Corporation. The company acquired the common shares of ChipMOS Technologies LTD. in 2007, Taiwan Occupational Safety and Health Management in 2008, and merged with Siliconware Investment Company Ltd. in the next year of 2009.
In 2013, the company and Siliconware USA, Inc. settled the long patent infringement litigation with Tessera Technologies, Inc. Siliconware would pay Tessera, Inc. a partial upfront fee and smaller quarterly payments over the next five years, for being released from the litigation.
Products and services.
The packaging materials the company processed include substrate (ball grid array) and lead-frame packages, the testing services provided by the company are based on logic, mixed-signal, and embedded memory devices to measure the performance and reliability of packaged semiconductor devices. In addition, the company also provides turnkey service, shipment service, and other related services, such as wafer probing, tape and reel services.
Products of the company are under ISO 9001 certification, QS 9000 certification, ISO 14001 EMS International Certification, TS16949 certification, OHSAS 18001 Certification, IECQ HSPM certification, ISO 14064-1 verification, PAS 2050 verification.
The company competes with Advanced Semiconductor Engineering, Inc., Amkor Technology Inc., and STATS ChipPAC Ltd.


Aluminum polymer composite

An aluminum polymer composite (APC) material combines aluminum with a polymer to create materials with interesting characteristics. In 2014 researchers used a 3d laser printer to produce a polymer matrix. When coated with a 50-100 nanometer layer of aluminum oxide, the material was able to withstand loads of as much as 280 megapascals, stronger than any other known material whose density was less than , that of water.
Aluminum foam.
Spherical aluminum foam pieces bonded by polymers produced foams that were 80-95% metal. Such foams were test=manufactured on an automated assembly line and are under consideration as automobile parts.
Thermal conductivity.
Experimentally determined thermal conductivity of specific APCs matched both the Agari and Bruggeman models provide a good estimation for thermal conductivity. The experimental values of both thermal conductivity and diffusivity have shown a better heat transport for the composite filled with large particles.


Moving magnet actuator

A moving magnet actuator is a type of electromagnetic linear actuator. It typically consists of an arrangement of a mobile permanent magnet and fixed coil, arranged so that currents in the coil generate a pair of equal and opposite forces between the coil and magnet.
A voice coil actuator, also called a voice coil motor (VCM), is an electromagnetic linear actuator where the magnet is fixed and the coil is mobile. In this configuration the coil is common called a voice coil.


Rapid Heat Cycle Molding

Rapid Heat Cycle Molding (RHCM) is also known as steam injection molding. Dr. Chao-Tsai Huang has written an extensive 68 page paper outlining, among other things, a case study on RHCM. His paper is entitled In-depth Study of RHCM and IHM Technologiesand Industrial Applications.
In general, ABS material is used as the raw material. The primary advantage of steam injection is that it eliminates weld-lines on molded parts. This allows companies to eliminate future processes such as painting. In non-steam molding, water will heat the tool to a constant temperature. Plastic will be injected to the warm tool.
In steam molding, steam is injected at 160 degrees to heat the tool. When the tool reaches a predetermined temperature (about 140 degrees), the plastic is injected. Cold water is immediately added to the process to cool the plastic down to around 40 degrees.
Because the mold is so hot when the plastic is injected, there are no weld lines, and a "perfect" product results. Steam injection molding is now being extensively used to produce the front covers of LCD TVs.


Laser engineered net shaping

Laser powder forming, also known by the proprietary name (laser engineered net shaping) is an additive manufacturing technology developed for fabricating metal parts directly from a computer-aided design (CAD) solid model by using a metal powder injected into a molten pool created by a focused, high-powered laser beam. This technique is also equivalent to several trademarked techniques that have the monikers direct metal deposition (DMD), and laser consolidation (LC). Compared to processes that use powder beds, such as selective laser melting (SLM) objects created with this technology can be substantially larger, even up to several feet long.
Method.
A high power laser is used to melt metal powder supplied coaxially to the focus of the laser beam through a deposition head. The laser beam typically travels through the center of the head and is focused to a small spot by one or more lenses. The X-Y table is moved in raster fashion to fabricate each layer of the object. The head is moved up vertically after each layer is completed.
Metal powders are delivered and distributed around the circumference of the head either by gravity, or by using a pressurized carrier gas. An inert shroud gas is often used to shield the melt pool from atmospheric oxygen for better control of properties, and to promote layer to layer adhesion by providing better surface wetting.
Other techniques.
This process is similar to other 3D fabrication technologies in its approach in that it forms a solid component by the layer additive method. The LENS process can go from metal and metal oxide powder to metal parts, in many cases without any secondary operations. LENS is similar to selective laser sintering, but the metal powder is applied only where material is being added to the part at that moment. It can produce parts in a wide range of alloys, including titanium, stainless steel, aluminum, and other specialty materials; as well as composite and functionally graded materials. Primary applications for LENS technology include repair and overhaul, rapid prototyping, rapid manufacturing, and limited-run manufacturing for aerospace, defense, and medical markets. Microscopy studies show the LENS parts to be fully dense with no compositional degradation. Mechanical testing reveals outstanding as-fabricated mechanical properties.
The process can also make "near" net shape parts when it is not possible to make an item to exact specifications. In these cases post production process like light machining, surface finishing, or heat treatment may be applied to achieve end compliance. It is used as finishing operations.


StreetStrider

StreetStrider is the brand name for a mobile elliptical trainer. The StreetStrider consists of a T-shaped lower frame to which two front wheels and a rear wheel containing a drive assembly are attached, and an upright frame to which two reciprocating arm levers are attached. Two elongated foot platforms on either side of the lower frame are attached to cranks as part of the drive assembly, which, as with bicycle drivetrain systems, also includes a hub, a rotating axle, and an internal hub gear system translating the axle rotation to the hub. The StreetStrider drive assembly is either chained or chainless direct drive, depending on model. The lower end of each arm lever is attached to the front end of each foot platform, which, by connection in the rear to the rotating crank arm and in the front to the pivoting arm lever, moves generally in an elliptical path. The device also includes a leaning mechanism for steering, as well as brakes and multiple gearing. It was developed by David W. Kraus, who wrote the patent for the device.
The StreetStrider duplicates the motion of a stationary elliptical trainer in a mobile device. The rider achieves a full-body weight-bearing low-impact high-cardiovascular workout while moving outdoors. With a branded trainer stand, adult StreetStrider models can be fashioned into stationary elliptical trainers, enabling indoor use during inclement weather. The StreetStrider can be used for physical fitness, weight loss, physical therapy, human-powered transport, and outdoor adventure.