Optimal cooling design in injection moulding process – A new approach based on morphological surfaces

The design of the cooling channels in the thermoplastic injection process is one of the most important steps during the mould design. An inappropriate cooling will lead to defects in the part and a low production rate. In this paper, a new approach with no a priori for the design of the cooling channels is presented for the determination of the cooling system of a 3D industrial part. Based on morphological concepts, the idea of regulation of the temperatures of the polymer and the mould by a cooling surface is introduced. The methodology is decomposed in two steps: the first step leads to the determination of the optimal fluid temperature distribution along the cooling surface in order to minimize an objective function composed of two terms linked to the quality of the part and the productivity of the process. The conjugate gradient algorithm coupled with a Lagrangian technique is implemented for the determination of the distribution of the fluid temperature. The second step illustrates the transition from cooling surface to discrete cooling channels, based on the analysis of the isothermal surfaces in the mould.

► Determination of the location, number and shape of cooling channels and of the coolant fluid temperature.
► Definition of a cooling surface enveloping the plastic part determined by morphological analysis.
► Determination of the optimal temperature profile along the cooling surface that minimizes an objective function.
► Design of discrete cooling channels based on the shapes of isotherms in the mould in periodic steady-state.
►  Application of the whole methodology to a three dimensional industrial plastic part.