3D BEM-based cooling-channel shape optimization for injection molding processes

Abstract

-Today, around 30% of manufactured plastic goods rely on injection molding. The cooling time can represents more than 70% of the injection cycle. Moreover, in order to avoid defects in the manufactured plastic parts, the temperature in the mold must be homogeneous. We propose in this paper a practical methodology to optimize both the position and the shape of the cooling channels in 3D injection molding processes. For the evaluation of the temperature required both by the objective and the constraint functions, we must solve 3D heat-transfer problems via numerical simulation. We solve the heat-transfer problem using Boundary Element Method (BEM). This yields a reduction of the dimension of the computational space from 3D to 2D, avoiding full 3D remeshing: only the surface of the cooling channels needs to be remeshed at each evaluation required by the optimization algorithm. We propose a general optimization model that attempts at minimizing the desired overall low temperature of the plastic-part surface subject to constraints imposing homogeneity of the temperature. Encouraging preliminary results on two semi-industrial plastic parts show that our optimization methodology is viable.

Modeling and Optimization of the Injection‐Molding Process: A Review

“…They presented a practical methodology to optimize both the position and the shape of the cooling channels in the IM process. Later, Pirc et al 131 extended this methodology to optimize both the position and the shape of the cooling channels in 3D IM simulations. The results for the simple geometries were encouraging, but the efficiency of the optimization could be improved to handle more complex shape variations.…”

“…They presented a practical methodology to optimize both the position and the shape of the cooling channels in the IM process. Later, Pirc et al . extended this methodology to optimize both the position and the shape of the cooling channels in 3D IM simulations.…”

Efficient mold cooling optimization by using model reduction

“…In order to avoid multi-domains calculation and save computation time, the plastic part is taken into account via a heat flux q p imposed on the mold cavity surface. The flux density q p is calculated from the cycle time and polymer properties [20,29].…”

Optimization of BEM-based Cooling Channels Injection Moulding Using Model Reduction

“…The optimization method allows updating the cooling channel design parameters (subject to the constraints) until a minimum of the cost function is reached [5]. Figure 1 shows the coupling between the thermal solver and the optimization algorithm.…”

“…An interesting side effect is the considerable reduction in size of the linear system to be solved [5]. The transient heat conduction in a homogeneous isotropic body Ω is described by the diffusion equation [6], where a is the material diffusion:…”