ガラスインサート金型による型内三次元樹脂流動挙動の可視化解析
Visual Analysis of Three Dimensional Melt Flow Behavior Using a Glass-Inserted Mold
横井秀俊・梅山 浩・宇高 靖・村田泰彦
Yokoi, Hidetoshi / Umeyama, Hiroshi / Utaka, Yasushi / Murata, Yasuhiko
To perform detailed analyses of injection molding phenomena inside cavities with complicated shapes, it is very important to observe the behavior of three dimensional melt flows. In this paper, we have proposed a "three-dimensional (3-D) visual mold" that enables simultaneous observation of the mold filling process from both the vertical direction to the parting face and the direction along the cavity thickness. Based on the above mold and an image measurement system which displays images of both directions on a single monitor, we investigated 3-D flow at the base of a rib portion, step change portion and a corner portion. In conclusion, we obtained the following results.
(1) Immediately after the flow front reaches these above-mentioned portions, the flow front advance velocity increases in the flow direction.
(2) Based on the observations of molded product surfaces, it has been confirmed that a dull surface is formed on the surfaces, opposite to these above portions and the locations precisely correspond to the areas where the flow front velocity shows variation.
(3) Since the melt's contact pressure to the cavity wall near the flow front is reduced at the moment the melt begins to form a diverging flow into these above portions, the surface properties of the cavity wall can not be sufficiently transferred to the surface of the molded products. We presume that this is the mechanism for the dull surface formation.
Key words: Injection molding / Visual analysis / Three dimensional flow behavior / Glass-Inserted Mold / Dull surface