The special tooling & machining industry and its customers
The special tooling and machining industry in the Americas, Asia, and Europe is comprised, in the majority of cases, of independently owned companies. These companies could be described as the prototype of all small business. They design and build special tools, dies, jigs, fixtures, moulds, die-casting dies, gages, special machines, and precision machined parts and components. Some of the companies in this industry specialize in single machining processes. The companies usually work with metal but are not limited to any specific material. They often engage in auxiliary work, such as metal stamping, proprietary products and production, but their primary business is the custom manufacture of special tooling or precision machining. Some firms also specialize in experimental and research and development work.
The companies in this industry use a wide variety of equipment and processes, including all machine tools from the simplest engine lathe to the most complex CNC machining centre, electrical discharge machine (EDM), sonic grinders and lasers. Equipment measuring in microns (.0001 inches) is considered commonplace. Computers are regularly used in design, machining, and in control of operations. Materials worked range from ordinary steel to the most exotic alloys, as well as plastics, non-ferrous metals, and non-metallic ubstances.
Among the major customers of the special tooling and machining industry are: automotive, aerospace/aircraft, appliance, consumer products, agricultural implements, medical, electronics, semiconductor equipment, and many others. In fact, almost every manufacturer relies on the services and products of the special tooling and machining industry.
Tool, die and jigs
The phrase "tool and die" is applied to describe much of the traditional work and products of the special tooling and machining industry. The various types of dies generally are made up of two halves, an upper and lower portion. Material is placed between these upper and lower halves and is cut, shaped or formed by the die and the two portions are closed upon the material. These dies, which are made by some of the most highly skilled craftsmen in the world, are used in machine tools such as stamping presses or forging presses. Automobile fenders, aspirin tablets, coins, and easy-open can tops are some familiar products that are processed by dies. Dies allow a great many identical, interchangeable parts to be made from the same set of tooling.
Very large stamping dies, such as those used to produce automobile components, begin with a computer designed model. They are then finished and ground by skilled craftsmen and sophisticated machine tools to exacting tolerances.
One set of these large dies may weigh up to one hundred tons or more and will
produce many hundreds of thousands of identical, interchangeable parts.
Stamping dies can be used to make large quantities of dependable parts from
sheet metal in an almost infinite variety of shapes and sizes. Since the costs of producing the tooling are spread out overlong production runs, unit part costs are kept to a minimum. In addition, each part produced by the same die is identical, quality of the finished parts is completely uniform, and replacement is simple.
Everyday items often taken for granted are triumphs of tool engineering. High
production does often run continuously for three shifts per day, five or six
days per week, and may produce over one million units before requiring maintenance or re-sharpening.
Moulds for plastics
Moulds for plastics (as well as rubber and other softer materials) are similar to dies in that they usually consist of an upper and lower portion. Plastic or other material is heated to a workable temperature and is compressed or injected into the mould cavity. The material quickly hardens as the halves of the mold are opened and the parts may be extracted. Moulds often have heating and cooling piping built into the tool itself to allow for uniform temperatures within the cavity in which the material is formed. Virtually all of the plastic things in our everyday life have been produced in moulds. Mouldmakers use the same high levels of machining and assembly skills as die makers.
Moulded plastics have been used as replacements for many materials which are
more costly or more difficult to work with. Moulds with textured beryllium-copper cavity surfaces can produce "wood grained" parts that not only look like wood, but also feel like wood.
A single cavity mould produced for a complex electronics component's housing
required 1,756 critical dimensions for the housing itself, and 5,541 dimensions for the tool drawings. The mould contains approximately 300 bypass shutoff valves to insure uniform temperature and pressure within the mould.
Moulds for metals
A carburettor body is typical of the sort of complex metal part that can be
effectively made by a die-casting die. Soft metal such as aluminium or zinc
is melted and forced into the die cavity under pressure through channels in
the die called "runners." The molten metal cools and hardens quickly and finished hardened parts are removed when the die opens. Since the metal in the runners also hardens, the runner must be trimmed from the finished part.
Molds for metals are often referred to as die-casting dies.
Precision machinists use tool making techniques to produce close-tolerance parts, from single prototypes to production, for high-technology applications such as aircraft and space components, surgical equipment and electronic components. Highly skilled machinists utilize advanced technology to create parts crafted from almost every conceivable material...from plastic to aluminium, stainless steel, copper, titanium, as well as a wide range of exotic metals. Computer-controlled machine tools help ensure that each part is exactly the same as the previous parts.
Special purpose machines are designed and built for a variety of purposes which include assembly, forming, material removal, packaging, testing or combinations of these and other operations. A typical special machine application is for the finish machining of carburettor body castings. A special machine of this type would consist of a variety of "stations" to automatically position, mill, drill, tap screw threads, deburr and perhaps perform a final inspection or test of the finished part. Special machines often use conveyor systems to transport parts from station to station.
The automotive industry is one of the biggest users of special machines. Connection rods, carburettors and oil filters are among the many products that are machined or assembled on this type of equipment. Special machine builders use all of the skills of the toolmaker, plus a thorough knowledge of electric motors, hydraulics, gear drives and wiring.
Assembly and testing systems are often applied in highly regulated medical device manufacturing environments