Computer simulation for prediction of thermal distortion of JIS ADC12 flat-shape die-casting

A computer simulation method to predict the thermal distortion value of a high-pressure die cast part was investigated. The evaluated product was a flat-shape JIS ADC12 part. The actual distortion value of the part was measured by an optical 3D digitizer and it was compared with the predicted distortion value. In this method, the initial temperature distribution of the part was determined by casting simulation. The thermal distortion value during cooling was calculated by FEM analysis. The stress-strain relation was approximated by the elastic-perfectly plastic material model including the temperature dependence of the yield strength. It was found that the heat-transfer coefficient between the die and the injected molten metal is a critical factor to implement an accurate FEM simulation in the casting simulation. The heat-transfer coefficient value was accessed and confirmed using the temperature distribution measured by a thermo camera. The distortion values of the actual part optically measured as a function of the curing time well coincided with the simulated value. It was concluded that the method can predict the distortion within a practically accepted preciseness.

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