Study On The Method Of The Deformation Evaluation Of The Pattern On The IMD Film

With the plastic used in all kinds of fields widely, the requirements of surface decoration technology had been improving. The traditional technology of surface decoration had gradually unable to meet the requirements of the new products, so the in-mold decoration(IMD) technology came into being. But in the actual production, the deformation of the pattern on the IMD film often lead to low surface quality of the product. For this situation, this paper presents a method to evaluate the deformation of the pattern accurately and quantitatively. The specific work is as follows:(1) A evaluation method is built for the deformation of the pattern on the IMD film. It can quantitatively evaluate the deformation of the pattern in different areas by two aspects of the geometry and the color.(2) The deformation data of the grids on the film of the simulation model and the actual product is respectively extracted by the means of the secondary development of ABAQUS software post-processing and the measurement and image processing technology. Depending on the design of python algorithms, these data can change to the deformation data of the grids of the pattern. And after constructing the cubic B-spline surface of the film, the evaluation parameters are calculated.(3) The evaluation model of the color-changing of the pattern is built, and the color difference value is the main evaluation parameter. The color difference value is displayed in the form of cloud picture. It can be used to evaluate and analyze the color-changing in different areas of film.(4) The evaluation model of the geometry-changing of the pattern is built, and the evaluation parameters are the area-changing of grids, the linear distortion, the variation of tensile ratio and the angle-changing. These values are displayed in the form of cloud picture. They can be used to evaluate and analyze the geometry-changing in different areas of film.(5) The evaluation method and algorithms are applied by examples and analysis by simulation, the results prove that they are reasonable.