Analysis, Planning, Modelling and Presentation of an SPF Model-Plant in Virtual Reality

Superplastic forming (SPF) is well known in aircraft production of Titanium and Aluminium parts. The process technology is commercially interesting for small quantities. The advantage of low upfront cost for the tooling is quickly lost however in conjunction with the longer cycle times of forming under purest SPF conditions. At given production rates typical for the aircraft industry the technology has an economical advantage over conventional, ambient temperature sheet metal forming processes. Compared to established processes the break-even point is at about 400 to 4000 parts/year, depending on the metal alloy and the geometry. Transfer to high volume production as afforded by automotive production of niche products calls for a modified forming process and an optimisation of the production flow. One alternative for a modified process is called “Hot Gas Pressure Forming” (HGPF). This process is very comparable to SPF, but the applied strain rates are much higher than recommended for SPF. HGPF can be applied in combination with a pre-forming operation done by cold or hot forming. The production line which has to be created to establish a constant production flow of outerbody parts like doors, inner and outer, fenders, bonnet and trunklid, inner and outer and roof for a project with an annual production quantity of ~30 to 40 000 cars has been engineered on the basis of the material’s forming behaviour studies, process investigations, cost analysis studies, etc. The elements of the production line like presses, interstockers, transportation , etc have been defined and placed with the help of a production simulation tool to get the best efficiency combined with suitable flexibility.