Analytical computation of the plunger kinematic parameters affecting quality in HPDC

High Pressure Die Casting (HPDC) is one of the most used process for manufacturing Al alloy components, thanks to its high production rate. Nevertheless, HPDC is considered a “defect generating process”, due to high scrap percentage usually detected. Thus, the identification and the computation of the parameters affecting quality of castings is the challenge towards an efficient and effective production. In their previous work, the Authors have found and statistically validated a novel parameter explaining and forecasting both static mechanical properties and porosity of the castings. Such a parameter, defined as the Root Mean Square value of the plunger acceleration in the second phase, represents a measure of the average force transmitted by the plunger to the melt, and has been proved to be more effective than speed in predicting the casting quality. In order to provide a tool for the practical use of this novel and effective approach, this work proposes an analytical method for computing this influential parameter, starting from the plunger displacement curve or just some notable points. The method formulation takes advantage of the analytical development of the typical motion primitive adopted for this kind of process. Hence, the optimization of the process can be achieved by selecting in advance the characteristic of the most suitable motion profile of the plunger that allows improving the quality of castings. Besides the theoretical formulation, experimental validation is provided to demonstrate the correctness of the proposed parameter and of the analytical approach, as well as its ease of implementation that makes it suitable for being used in industrial manufacturing plants.