実成形時の冷却速度分布により発生するそり発生メカニズム

―金型温度非対称条件が樹脂流動に与える影響―

抄録

In some cases, warpage failure occurs in the injection molding plate. This warpage can be predicted by using injection molding CAE. However, the prediction accuracy is not enough in the warpage analysis of injection molding CAE. The warpage generation mechanism changes according to the material and shape. The mechanism has not been clarified in each condition. For example, there is difference in the cooling speed of the real injection plate in each position.
In this report, we considered the influence of the difference of mold temperature on warpage, assuming the mold temperature to be an asymmetric condition. And the following conclusions were arrived at. Moreover, upon examining the influence of mold temperature difference on warpage of PP plate, the following conclusions were obtained.
1) The amount of warpage grows in an asymmetrical mold temperature condition. The amount of warpage increases in the case of high mold temperature even if the difference of temperature between fixed side and moved side is constant.
2) In the case of asymmetrical mold temperature, the distribution of crystallinity becomes asymmetrical in the thickness direction. However, the thermal expansion coefficient is isotropy and constant.
3) The key factor of warpage in asymmetrical mold temperature conditions in PP is induced by thermal effect.
4) The resin flow of asymmetrical mold temperature conditions in PP becomes a symmetrical flow. This is thought to be influenced by heat of shearing and latent heat of crystallization.
5) Even under the same mold temperature asymmetric condition, differences in material cause the influence of mold temperature on flow to differ.