| 摘要 |
PURPOSE: To enhance tensile and bending breaking strength to stabilize quality by utilizing fiber-containing effect by generating contraction flow in a root part ready to be structurally reinforced in a resin flow direction to largely change the orientation of a fiber in the contraction flow part. CONSTITUTION: In an injection process of a columnar test piece, when a product part cavity is filled with a molten resin from the gate 3 of the region 4B corresponding to a thick-walled part, the fiber in the molten resin at the root part 4C of the thin-walled part 4A continuing to the thick-walled part 4B is strongly oriented in a resin flow direction by the contraction flow shown by an arrow from the thick-walled part 4B to the thin-walled part 4A. When the wt. average fiber length in the molten resin is large, this tendency becomes marked and the strength against load is enhanced. Contrarily, when the product part cavity is filled with the molten resin from the gate 3 of the region A of the thin-walled part and the resin flows so as to expand from the thin-walled part 4A to the thick-walled part 4B, the fiber in the molten resin at the root part 4C of the thick-walled part 4B is strongly oriented in the direction right-angled to flow and, therefore, the fiber becomes orientation disadvantageous against load. |
