Metal injection moulding

Use of Table 18.2 is intended only as a guide, as it is difficult to give precise values. For instance, casting masses depend on the material being cast, accuracy depends on size, and so on. 

Once the feedstock, after a predetermined cycle, has hardened, the mould is opened, the compact ejected and picked up by a robotic handling unit to avoid any damage to the green compact. 

Depending on the part, this can be tbe final step, unless there are secondary operations to be performed, e.g. tapping threads. 

Almost any metal that can be produced in a suitable powder form can be processed by metal injection moulding. Aluminium is an 

Typical tolerances that can be achieved ate 0.08mm/2Smm i.e. on a 25 mm diameter the achievable tolerance would be 0.08 mm. 

For example, if the component under consideration is to be made from aluminium alloy and only 2000 per year are required, the choice would be limited to gravity die-casting. If, however, the quantity required was 50000 per year then the high-pressure cold-chamber method would be appropriate. 

Fine metal powder is mixed with a binder system to create a feedstock. The binder is a mix of wax and plastics and makes up roughly 50% by volume of the feedstock. The feedstock, in the form of granules, is injected under high pressure into a mould cavity using moulding machines 

Die- casting method Economic run per year Accuracy Casting mass General minimum thickness of section Type of metal cast Rate of prodn Surface finish Die costs Capital cost of equipment 

Gravity 1000 Good Up to about 23 kg or more 3-5 mm Al alloys Cu alloys Mg alloys Medium Good High Nil to very little 

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What type of metal is unsuitable for metal injection moulding and Mty ... 

Describe briefly the metal injection moulding process. 

What is the name given to the mix of powder and binder in the metal injection moulding process ... 

Where required, chapters have heen updated in line with current developments, e.g. lost foam casting and metal injection moulding. 

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