A LUMPED-PARAMETER ANALYSIS OF POWDER INJECTION-MOLDING

This paper presents a combined experimental and analytical study on a lumped parameter analysis of the powder injection molding process. The analysis uses a simplified control volume approach to study an otherw ise complex problem. To obtain a reliable analysis, most of the assump tions used in the previous work have been eliminated A new thermal mod el has been introduced to include conduction and die thermal propertie s for an improved temperature analysis. The transient injection speed response of the molding machine has been modeled to obtain a reliable actuator pressure prediction during mold filling. The analytical model is flexible to allow easy application to various injection molding ma chines and feedstocks. Experiments have been conducted on an injection molding machine to determine the machine related parameters. Some of these included leakage through the screw tip, friction between the bar rel and the screw, amount of stroke overshoot during filling, and pres sure overshoot during packing. The simulation analysis has been applie d to various shapes using different process conditions. The predicted results are in good agreement with the experimental data.