squeeze casting: the future - International Specialised Skills Institute

Executive SummarySqueeze casting is a relatively new casting technology when compared with traditional sand casting,which dates back to between 2000 and 3500 BC. Squeeze casting has number of advantages,including the elimination of gas and shrinkage porosities, the reduction or elimination of metal wastagedue to the absence of feeders or risers, and the possibility of the manipulation of processes to achievethe required optimum parameters.Squeeze casting can be applied to high integrity parts like suspension arms, brake calipers, aluminiumwheels, steering knuckles, vanes, ring groove reinforced pistons, connecting rods, rotary compressorvanes and shock absorber cylinders, to name a few.Squeeze casting is a die casting method based on slower, continuous die filling and high metalpressures. Laminar die filling and squeezing, which is the application of pressure during solidification,ensures that the component is free from blowholes and porosity. This method produces heat-treatablecomponents that can also be used in safety-relevant applications and are characterised by higherstrength and ductility than conventional die castings.The die casting process is the high-speed injection of a molten metal alloy into a steel mould. Thisalloy then solidifies rapidly (solidification time varying from milliseconds to a few seconds) to form a netshaped component and is then extracted from the mould. During the die casting process the die isfilled at high speed, but during squeeze casting the filling process takes longer, from a half-second tothree seconds. This slower approach permits a die filling that is virtually free of gas entrapment.Dr Amita Iyer’s current observation of the Australian context suggests that manufacturing industriesare still sceptical about the use of squeeze casting; considering it as a relatively new technology whencompared to conventional die casting methods.The aim of the Fellowship was to provide the opportunity for Dr Iyer to develop a comprehensiveunderstanding of how others in the world of the manufacturing industry are embracing squeeze castingand implementing it easily and successfully. The Fellowship itinerary included visits to CONTECH,Ryobi die casting, CWRU University, and NADCA, all in the USA.The Fellowship provided a valuable opportunity to undertake a comprehensive investigation of theprocess parameters and skills required to maximise the potential of squeeze casting within theAustralian context.Key areas of study included:• Identification and assessment of various approaches being employed by the squeeze castmanufacturers, and highlighting those considered to be best practice.• Visiting professional associations to gauge the status of squeeze casting overseas.• Collecting, recording and analysing the manufacturing techniques of squeeze casting.• Identification of any special die requirements for squeeze casting.• Identification of the difference between standard die casting and squeeze casting methods.• Identification of post-finish operations on squeeze casting parts, such as machining and/or heattreatment.• Determining the influence of squeeze casting parameters on mechanical properties andmicrostructures.• Identification of the relationship between the design of the part, the process variables and thesoundness of the squeeze cast part.