A new way to produce conformal cooling channels by RPT for moulding blocks of the hybrid moulds

Hybrid moulds are an increasingly considered alternative for prototype series or short production runs. In this solution of injection moulds the moulding elements (blocks or other inserts) are manufactured in alternative metallic materials or in synthetic materials. One of the main issues associated to the use of these alternative materials is their thermal behaviour. For instance, in order to allow uniformity in the cooling of the moulded part, and a significant cooling time reduction, conformal channels are recommended as an efficient solution. The layout of the channels should contour the geometry of the impression, and has to be easily implemented during the production of the moulding blocks. This paper reports on a case study involving the use of conformal cooling channels obtained in wax by 3D-impression. An injection hybrid mould of a simple geometry production was used for testing several possibilities of conformal cooling construction. The discussion of cure parameters of the epoxy-based composite resin that can have influence on the wax thermal properties is presented alongside with recommendations for the use of this rapid tooling technique.