Design of Injection Mold for Instrument Panel Body
The instrument panel body product is shown in Figure 1. The maximum size of the product is 343.40 mm x 167.13 mm x 48.01 mm, the average thickness of the plastic part is 2.00 mm, the material of the plastic part is PP TD40, the shrinkage rate is 1.010, and the quality of the plastic part is 208.88 grams. The technical requirements for plastic parts are that there must be no defects such as peaks, dissatisfaction with injection molding, flow lines, pores, warpage deformation, silver streaks, cold materials, jet lines, etc.
The instrument panel body is the internal bracket of the instrument panel of a Japanese car. It can be seen from Figure 1 that the structure of the plastic part is a flat and complex shell, the movable and fixed molds have many bone positions and column positions, etc., the size is relatively large, and the mold is a large mold. See the attached file for the product drawing of the plastic part and the 3D drawing of the mold. The material of the plastic part is PP TD40, and the material is added with calcium carbonate filler, mainly to increase the rigidity and fatigue resistance of the plastic part, and play the role of shock absorption and shock absorption.
Due to the large size of the plastic parts, the mold design cavity ranking is 1 out 1, the injection molding machine is 220 tons of Nissan, and the specifications of the 220 tons of JSW injection molding machine are shown in Figure 5, the mold design drawing is shown in Figure 2, and the mold design specification is shown in Figure 4.
The mold design style book is an important document for commodity mold design. It stipulates the number of mold cavities, the way of plastic injection, the brand grade of mold core steel and standard parts, mold life, injection molding machine model and injection cycle, etc., which are the basis for mold design. The most common terms of Japanese molds are briefly introduced as follows:
Matching meeting-mold review meeting; hooking-demolding angle; mold force-clamping force; gold mold-mold; model see this-test pattern Product
Inch method-----size; tip R------spherical surface of sprue sleeve;
The mold review meeting is also called the mold meeting meeting in Japanese companies. Review the product and mold structure problems and improvement countermeasures, determine the mold parting surface, ejection method and gate, all review content should be marked with red and blue pencils or pencils in the product drawing and written in the mold specification book. After the review is completed, fill in the relevant review record, stamp on the drawing, and sign for confirmation by both parties.
The guide pin and sleeve of the mold are the primary positioning of the entire mold. Because there is a gap of 0.01-0.03mm between the guide pin and the hole of the guide sleeve, for large molds, it is obviously not enough to rely on the guide post and the guide sleeve to locate. Four conical positioning parts are designed on the four sides of the mold base. The three-level positioning refers to the precise positioning of the design tiger's mouth on the mold core, which mainly protects the precise positioning of the inserting surface of the mold. The instrument panel body mold is designed with two three-level positioning systems. The first is the positioning of the tiger's mouth around the guide post and guide sleeve of the mold blank, and the second is the design of the tiger's mouth positioning at the four corners of the front and rear mold cores of the mold. The design of so many positioning is mainly due to the fact that the instrument panel body mold is a large mold, and there is an eccentric design configuration of the mold core, so it is very important to design effective positioning and guidance. In order to balance the clamping force, a balance block is designed on the parting surface 5.
The exhaust of large injection molds is very important. For export molds, the exhaust must be analyzed in advance, focusing on the areas that are prone to trapping, and design the exhaust on the mold drawing. The vent groove should also be ground on the edge of the insert to facilitate injection molding and filling.
Due to the large size of the plastic parts, the cavity is ranked 1 out of 1 eccentrically. The mold base is the standard mold base CH5565, and the front and rear mold cores are positioned and locked by squeezing blocks. Positioning pins are added between the movable mold B plate, square iron, and bottom plate to maintain the rigidity of the mold. The area of plastic parts is large and the process of molten plastic is long, so the design of the pouring system is very critical. Considering that there are many bones and holes in plastic parts, there are many factors that affect the flow of molten plastic, and the filling resistance is relatively large. Therefore, the gating system is designed with a 3-point latent gate to feed the glue, and the gate position is on the same side of the plastic part. The runner pull pin is designed with a tapered pull pin, which is convenient for the manipulator to grab the nozzle material. See the enlarged view of the runner system in Figure 2 of the mold design.
The ejection system of plastic parts adopts thimble and cylinder to eject. In order to make the ejection system smooth, some innovative designs have been made. The middle support guide post 13 is designed, which is guided by a graphite middle support. The top of the middle support guide post 13 is fixed on the back of the B board with a positioning pin, and the bottom is fixed on the bottom plate of the movable mold with screws. This design of the center support guide post has the best guiding performance and overcomes the disadvantage of the traditional center support guide post and the thimble plate of poor verticality. At the same time, the middle support guide post 13 can also function as a support head. For the convenience of mold installation, M10 threaded holes are designed on the end of the back pin to facilitate tightening of the ejector plate. At the same time, a limit screw 17 is designed on the ejector plate, and the top of the supporting head 11 and the supporting head 12 are designed with positioning pins. All the thimble uses Japanese MISUMI high-speed steel thimble SKH51.
The cooling system design of the mold is shown in Figure 3. The front and rear molds are designed with direct water and ponds, which effectively ensure the cooling effect.
ABIS MOLD TECHNOLOGY CO.,LTD
Daisy Wang (Sales Engineering)
M: +86-150 1652 6799
E: daisy@abismold.com
A: Building B#,YingKeli Industrial Part, LongDong Community, LongGang District, Shenzhen, China 518116
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