Design and manufacture of injection mould tool inserts produced using indirect SLS and machining processes

The purpose of this paper is to report on the use of a combination of indirect selective laser sintering (SLS) and machining processes to create injection mould tools, an approach designed to offer the capability to create conformal cooling channels in the core/cavity inserts together with the levels of surface finish and accuracy required to meet typical injection mould tool specifications.

The research has been pursued through three industrial case studies. In each study, existing injection mold inserts have been redesigned to give a conformally cooled tool. These have then been manufactured using indirect SLS, high‐speed machining, electro‐discharge machining and polishing. The inserts have been evaluated in industrial trials to assess their performance in terms of cycle time, energy usage, durability and quality. The insights gained from the three case studies have then been developed into a series of design rules, which may be applied in the development of tooling for new applications.

The results show that significant productivity improvements and energy use reductions in injection moulding are possible through the implementation of conformal cooling, and that the material has sufficient wear resistance to be used in production applications. However, it is recommended that modelling is always used to understand the impact of conformal cooling channels, and manufacture is carefully planned to ensure that the required internal geometry is created.

The paper presents new results on the impact of conformal cooling on the productivity and energy efficiency of injection moulding, and on the durability of the indirect SLS material in injection moulding applications. A novel “cut‐out volume” technique for powder clearing is also presented, along with a set of design rules to support further application of the work.