Optimized design of self-releasing microarray mold based on shape memory polymer

Abstract

To reduce demolding defects in the micro molding process, a new self-release molding approach is proposed for products with microarray structures. Specifically, shape memory polymer (SMP) is filled in the mold cavities and its shape memory effect is used to overcome the demolding resistance, enabling automatic demolding of the micro products. To study the feasibility of this process and improve the self-releasing molding effect, numerical simulation is carried out using ABAQUS. The analysis considers the internal stress in the products due to SMP’s unbalanced response, and the response status of the SMP fillers. These factors are used as indexes for a control variable study on the parameters of the self-release molding process. The results show that reducing the number of microarray structures, increasing the distance between pattern distributions, and constructing an array pattern with parallel edges can decrease defects in the finished products caused by the unbalanced recovery of the SMP. Additionally, reducing the diameter or height of the SMP filler, selecting the appropriate heating temperature, and extending the heating time facilitate the self-releasing. Finally, a comprehensive design method for self-releasing molds for microarray structures is gradually founded to provide guidance for future applications.