Analysing Powder Injection Moulding of a Helix Geometry Using Soft Tooling.

Alberto Basso,Jon Spangenberg,Yang Zhang,Jacob Kjeldahl Pløger,Hans Nørgaard Hansen

doi:10.3390/polym13234183

Abstract

Freeform injection moulding is a novel technology for powder injection moulding where a sacrificial 3D printed mould (i.e., a soft tooling) is used as an insert in the injection process. The use of 3D printed moulds enable a higher geometrical design flexibility as compared to the conventional injection moulding process. However, there is still very limited knowledge on how the sacrificial soft tooling material and powder suspension handles the increased geometrical complexity during the process. In this study, a stainless steel powder suspension is injected into a geometrically challenging sacrificial mould (viz. a helix structure) that is produced by vat photopolymerization additive manufacturing. Computed tomography is used to quantify the geometrical precision of the mould both before and after injection. In addition, a new numerical model that considers the suspension feedstock is developed to investigate the powder injection moulding process. The numerical results are found to be in qualitative good agreement with the experimental findings in terms of pinpointing critical areas of the structure, thereby highlighting a new pathway for evaluating sacrificial inserts for powder injection moulding with a high geometrical complexity.

Highlights

Powder Injection Moulding (PIM) is a well-established technology for mass manufacturing of metal parts
In addition to being more affordable, the use of Additive Manufacturing (AM) in a PIM process chain opens new avenues for the possible geometry of the final part, which overcomes some limitation of the traditional PIM process [10]
The photopolymer resin applied in the Vat-Photopolymerization Additive Manufacturing (VPAM) process was water soluble, which enabled the creation of the helix structure

Summary

Introduction

Powder Injection Moulding (PIM) is a well-established technology for mass manufacturing of metal parts. Nowadays the market demands new and highly customized products, forcing the producers to continuously update the moulds in their manufacturing processes. PIM is a profitable process for mass production, but in the case of prototyping or small batch production, the cost of the metal tools has an influential weight on the overall cost of the final parts [9]. An efficient way to reduce the manufacturing cost of PIM parts, when only a low number of units need to be produced, is to integrate Additive Manufacturing (AM). Moulds for soft tooling in PIM are generally produced via Material Extrusion Additive Manufacturing [11] or

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