ブロー成形の可視化
Direct Observation of Blow Molding Process from Inside the Parison
今村伸二・金田勉・九島行正・大田 彰・戸来稔雄・小山清人
Imamura, Shinji / Kaneta, Tsutomu / Kushima, Kousei / Ohta, Akira / Herai, Toshio / Koyama, Kiyohito
We have developed a method of directly observing the blow molding process from inside the parison, which enabled us to ascertain some important aspects of parison deformation. This method consists of observing the displacement and deformation of a parison through a fibescope inserted inside the parison.
During parison inflation, under various friction conditions, we confirmed that the parison does not slip against the mold wall and that the deformation takes place only in the "free" parison. We also observed that the "blow out" takes place at the highly deformed area of the "free" parison. This also supports the above observation.
We estimated the heat transfer coefficient from the surface temperature change of the parison before mold closing and the molded part after mold opening under various conditions. The heat transfer coefficient between parison and mold is estimated to be about 100 to 260 W/m2K.
On the basis of the above observations, we tried to simulate the inflation process using a general purpose FEM program (ABAQUS). The thickness distribution of a molded part, thus computed, was in good agreement with experimental results.
Key words: Blow molding process / Fiberscope / Parison / Heat transfer / Simulation (CAE) / Wall slip