Instrument window panel injection mold
The instrument window panel product is shown in Figure 1. The maximum size of the product is 317.93 mm x 167.80 mm x 118.80 mm, the average thickness of the plastic part is 1.50 mm, the material of the plastic part is PP TD20, the shrinkage rate is 1.012, and the quality of the plastic part is 161.18 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 window panel is the internal bracket of the front instrument panel of a Japanese car's cab. According to the requirements of the use of plastic parts, it is made of PP TD20. This material is made by adding calcium carbonate (talc) to PP to improve the physical properties of the plastic by adding fillers. The common use of PP material to add calcium carbonate is to manufacture refrigerator drawers and car bumpers. It can be seen from Figure 1 that the structure of the plastic part is complex. The plastic parts have large fluctuations in height and many small scratches on the edges. The main difficulties in the mold design of this plastic part are gate design, plastic part filling, how to ensure dimensional tolerances and how to prevent ejection deformation. On the other hand, the mold structure of the plastic part is simple, and there is no complicated structure such as a slider. The two inclined roofs are designed for ejection needs, to avoid clamping the plastic parts during ejection.
The size of the plastic part is relatively large, and the mold design cavity rank is 1 out 1. The mold design drawing is shown in Figure 2. The mold base is a non-standard mold base CI 5075 that imitates the standard mold base design. In order to adapt to the coding method of the Japanese injection molding machine, the mold base is chamfered on one side, and there is no design positioning ring. A large area sinking code mold slot is opened on the panel and the bottom plate. At the same time, design screw holes for code patterns on the sides of the panel and the bottom plate. The code pattern slots of the panel and the bottom plate are shown in Figure 4 and Figure 5 respectively. The parting surface spacing of AB board is designed to be 15, and two balance blocks 21 are designed on the movable mold side of the parting surface to balance the force of the mold. In the movable part of the mold, positioning pins are designed between the plates of the mold blank to increase the rigidity of the mold.
The gating system is designed with a latent gate design. The enlarged view of the sprue bushing design is shown in Figure 6. Here, the bushing is 0.2 to 0.25 larger than the sprue bushing on one side, so as not to form an undercut and affect the removal of the sprue material. After the molten plastic enters the parting surface from the sprue in the small mouth 01, it sneaks into the cavity from the center of the large round window through the latent gate.
The size of the plastic part is larger, so the size of the front and rear mold cores is correspondingly larger. Therefore, the lower frame of the mold core is positioned and pressed by the squeezing block. The four corners of the front and back molds are locked with tiger mouths. For the front mold core, combined with the structural characteristics of the plastic part, the front mold core is divided into two parts, and the two parts are locked with each other with an inclined plane, and locked together with screws. The piercing position of the edge of the plastic part is all made of inserts, see the 3D picture.
The height of the plastic part is large, the tightening force on the back mold is large, and the force is uneven. The two ends of the plastic part (the side of the mold world) are respectively designed with an inclined roof. For the rear mold, the ejection mechanism must be designed. If it is designed for a straight top, it will clamp the plastic part, so the inclined top is designed. The three semi-circular raised edges have the largest ejection force, and are designed with a straight top, and the other parts are designed with a thimble to eject.
In order to make the ejection mechanism smooth, a guiding mechanism must be designed for the ejector plate. The guide post 08 and the guide sleeve 09 adopt MISUMI standard parts to guide the ejection mechanism. This kind of guide post is directly inlaid on the back of the B board and the bottom plate, and the accuracy is higher than that of the guide post directly fixed on the bottom plate, and at the same time, it plays the role of supporting head. The travel switch 16 is designed to ensure the mold return. The ejector rod in the ejector hole is also designed with a special ejector rod.
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
WhatsApp: +86 136 8261 9739
Skype: daisymold@outlook.com