1. Structural analysis of plastic parts
The material is PP plus 30% glass fiber, the shrinkage rate is 1.1%. The structure of the plastic part is characterized by a small wall thickness of only 1mm, and the resistance of the melt filling is large, so attention should be paid to the design of the pouring system. There are five evenly arranged hollow cylinders with an inclination angle of 10°, and the cores should be drawn obliquely in the direction of the moving and fixed mold.
2、Analysis of injection mold structure
The injection mold adopts hot runner pouring system, which can change the melt filling (the wall of the plastic part is thin, and the resistance of molten rest filling is larger), and also can improve the labor productivity of the injection mold. The five oblique pillars of the mold are formed by both sides of the moving and fixed mold, and five oblique cores are designed respectively. The five oblique cores slide in the oblique holes of the moving and fixed mold and the T-slots perpendicular to the opening direction to change the opening movement into oblique movement, thus realizing oblique core extraction. For this purpose, an additional opening surface is added to each of the moving and fixed mold sections to convert the opening distance into the oblique core extraction distance. In order to ensure the safety and reliability of oblique core extraction during mold opening and resetting, Dongguan Machico Injection Mold Factory adopts a combination of external and internal fixed distance parting mechanism, and adds a travel switch on the fixed plate of the push rod. The plastic parts are pushed out by the pusher, which is simple and safe. Parts locking clasp, plastic injection mold processing transportation and storage warehouse before installed, production must be removed.
3. Injection mold working process
The melt enters the mold cavity through the hot runner, and after the injection molding is completed, the injection mold is opened under the pull of the injection molding machine. Under the action of the fixed distance parting mechanism and spring, the mold is opened from the parting surface 1 at a distance of 30mm, which is controlled by the limit peg. In this process, the oblique core extraction completes the oblique core extraction. Due to the action of the external fixed pitch parting mechanism, the mold opens from parting face 2 when the mold continues to open, and the movable and fixed dies are separated. When the mold opening distance reaches 20mm, the upper hook detaches from the moving mold plate, and the pull hook hooks the moving mold plate, then the parting surface 1 stops opening and the parting surface 2 starts opening. The opening distance of parting surface 2 is 20mm, which is controlled by limit peg. In this process, the movable mold will finish the diagonal core extraction and detach the plastic part. After the parting surface 2 is opened 20mm, the pull hook is released from the moving mold plate, the parting surface 2 continues to open, and after the mold opening stroke is completed, the injection molding machine pushes the push rod to push the plastic part out of the injection mold.