Investigate Techniques for Low-Volume Injection Molding Production

Because of expensive tooling, injection molding is only suited for large production volumes. Consequently, this makes it hard to justify making prototypes and small production volumes. In spite of recent advances in additive manufacturing, this technology can still not capture performance properties of injection molded products. This report proposes several ways of prototyping injection molded components by means of direct rapid tooling. By Wayfaring, several techniques could be explored. Molds were built using rapid prototyping techniques such as fused deposition modeling, selective heat sintering, laminated object manufacturing, polymer jetting and CNC-milling. The molds were tested using a desktop injection molding machine, and the molded components were tested using a three point bending setup. Furthermore, a more complex mold was CNC-milled and tested in a full scale injection molding machine with the tool insert method. The tested techniques were evaluated with respect to cost, efficiency and effectiveness. From the study, it was found that polymer jetting could fabricate the molds quickest and with best quality of the tested techniques. Furthermore, it was found that desktop injection molding could be a good way of prototyping small components, while the tool insert method is better suited for larger, more complex geometry, and for low-volume production.