Development of Bi-Material Rotational Mould Made by Additive Manufacturing and Electroforming

Abstract

This paper is focused on the development of mould for rotational moulding of plastic parts where the tool is made by electroforming of two materials starting from a model of additive manufacturing (AM). Rotational moulding is a technique to manufacture the hollow industrial parts .The mould aims to reduce the cycle time of the rotational moulding process which is usually very high related to any other process of polymers. The plastic model of 3D printing Polijet technology was used as pattern (cathode) for electrodepositing nickel as first thin layer and a thick layer of copper as the second one. The combination of high hardness of nickel and highcoefficient of thermal conductivity of copper provides to the mould high quality and efficiency for being used in the rotational moulding process. The paper presents all the process from the design of AM model, the electroforming process, manufacturing of proposed standardshell holder and finally a test of the mould, under real conditions, being compared to a conventional CNC machined aluminium mould.The main finding of the proposed process is to take advantage of additive manufacturing and electroforming, allowing the manufacture of complex and efficient bi-material moulds in rotational moulding (reducing cycle time even more than 15%), as well as approaching standardization of such innovative tooling.