Eliminated Risk: Very Large Thin Structural Auto Part
More than one meter long and just as wide, thin structural auto part for performance vehicle; average thickness ~2 to 2.5mm, with a few heavy attachment points. Never been successfully cast before. OEM was faced with a die re-design after the first attempt failed. Failures were due to part quality and parts sticking to the die and was never able to run the die in a steady casting process.
The OEM decided to have a “clean slate” approach and BHOLSTER was retained to guide the gating and cooling design. We relied exclusively on the science of die casting that we have isolated and calibrated over the years.
We optimized the runner and made some very minor product tweaks that dramatically improved metal flow and reduced trapped air in the cast part. Blisters and poor elongation in tensile bar tests were the failure modes relating to part quality. Die failure mode that they wish to avoid was die solder, part sticking and die running either too hot or too cold. Our simulated die temperature accurately predicted solder/sticking as well as solidification times. We pin-pointed the die features that needed to be cooled and also identified zones in the die that must be heated (with hot-water units). Our simulations specified the shot profile and zone temperature settings needed in order to make good parts at the target cycle time.
The result: First castings were nearly perfect! Minor tweaks to overflow placement was all that was needed to make tensile bars pass at one local area of the part. And the die was successfully “run at rate” and produced quality parts with our specified temperature zone and specified process settings.
The lesson that we learnt on this project was to abandon beliefs stemmed from decades of experience and trust the simple Physics that BHOLSTER calibrated and identified as relevant.
The most challenging part of this project was to was to trust the science and abandon conventional beliefs and practices. It was particularly difficult to convince the team to adapt this approach, but as soon as we took this approach, we were able to meet targets on time.