Application of Casting Process Optimization Tools to a Structural Aluminum Part Made Via the Low Pressure Casting Process

摘要

The low pressure casting process is a well-established route for the manufacture of large safety-critical non-ferrous automotive components. While smooth, ambient mold filling allows for a high degree of control over the process, the inherently long cycle time results in low productivity. The two most commonly made parts via the low pressure process are wheels and cylinder heads. More recently, this process has been successfully applied to the manufacture of bedplates and control arms, and some progressive casters are investigating the adaptation of this process for the manufacture of magnesium cylinder blocks. Even though the low pressure casting process takes advantage of directional solidification, feeding related issues in castings can often result in porosity problems after machining. Solving these problems usually requires stringent control of mold temperatures so as to promote directional solidification, and sometimes tooling changes. Using simulation capabilities is the best approach for predicting these porosity problems. This paper deals with a case study wherein the root cause of porosity outbreaks, evident in one of the bulkheads of a bedplate, was linked to feeding problems. Simulation tools were used to first analyze and predict the defect within the casting. Subsequent simulations with minor, yet important tooling corrections resulted in a quick solution that were then implemented on the shop floor resulting in significantly lower reject rates.