Design of Injection Mould for the Front Shell
The audio front shell product is shown in Figure 1. The maximum size of the product is 129.54 mm x 38.00mm x 35.94 mm, the average thickness of the plastic part is 1.80 mm, the material of the plastic part is ABS, the shrinkage rate is 1.004, and the quality of the plastic part is 16.56 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 structure of the plastic part is a heterosexual shell, and the design of the plastic part and the 3D mold is shown in the attached 3D drawing. It can be seen from Figure 1 that the two sides of the plastic part need to be designed with large slider cores. There is an inverted buckle at the end of the plastic part, which requires the design of a small slider for the front mold.
The production volume of plastic parts is huge. Because of the need to design large slider cores on both sides, the mold design cavity ranks 1 out and 1 is the best. The mold base is the standard mold base FC13035. The choice to simplify the fine nozzle mold base is mainly to save 4 guide posts and increase the space at the edge of the mold in order to facilitate the design of a wider slider. The glue feeding method of the plastic parts is to transfer the glue from the submerged nozzle to the submerged gate, making a submersible gate, the submerged column position, and the thimble is ejected before trimming.
The glue area of the sliders on both sides is large, and the lateral force is large. Therefore, the two large sliders are designed with backhoes. The shovel is a mosaic shovel, which is convenient for extending the movable mold as a backhoe. The two large sliding blocks are driven by oblique guide pillars. Since the top surface of the slider is a complex curved surface, in order to facilitate processing, the slider insert is selected to be inserted from the end surface to simplify the processing.
When designing the mold, the slider with a curved top surface cannot be designed as a whole. If it is designed as a whole, the connection between the curved surface and the slider seat requires EDM, which is time-consuming and labor-intensive, and it is not easy to adjust when flying the mold. The other front mold slider is driven by bending pins. In order to facilitate processing and venting during injection molding, the back mold has a large insert in the middle part, see 3D diagram. For the shape of the front mold core, pay attention to the strength of the mold core, and choose the pre-hardened mold steel NAK80.
The plastic part is ejected by a thimble. After the thimble is assembled, it needs to be twisted manually to detect. If it can be twisted easily, the gap is reasonable. Otherwise, the gap is too small and it is easy to burn to death during the ejection process, and it is difficult to exhaust. The ejection process needs to be stable to prevent the plastic parts from deforming, and the thimble plate needs to be designed with a center torsion guide. In long-life molds, heat-resistant thimble is required, and the surface is plated with titanium to increase wear life.
The cooling of the mold is that the front and rear molds are all cooled by straight-through water. The direct water flow is fast and the cooling efficiency is high.
There is a problem with the code model, which is often overlooked. For small nozzle molds, the panel is often very thick. In the part of the code mold, it needs to be milled thin. Keep the thickness 25~30 to ensure that the code mold can be pressed tightly.
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
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