Smart watch shell injection mold design
With the improvement of people's living standards, high-end smart watches have been widely used. The function of smart watches has also been extensively expanded. This article introduces the key points of the design of the injection mold for the smart watch case. The maximum size of the smart watch case product is 37.36 mm x 38.80 mm x 8.60 mm, the average plastic part thickness of the plastic parts is 1.95mm, the plastic material is ABS, the shrinkage rate is 1.005, and the plastic part quality is 3.89 grams. The technical requirements of plastic parts are that there must be no defects such as peaking, injection molding, flow pattern, pores, warping deformation, silver grain, cold material, spray pattern, air bubbles, etc., and mold release agents should not be used in plastic molding. There are 7 side holes on the side of the plastic part, which are the strap mounting holes and the adjusting button holes, which are divided into two groups, which are respectively placed on the left and right sliders.
Figure 1 Smart watch case product diagram Smart watch is a high-end consumer electronics product, which has high requirements for the appearance of plastic parts. Plastic parts need to maintain high dimensional accuracy and geometric accuracy to meet the appearance requirements, to meet the waterproof performance after assembly. There are four types of plastics that can be used to form precision injection molded parts: POM, PA, PC, and ABS. The smart watch case is made of ABS. It is made of ABS material that can form precision plastic parts and has excellent injection molding properties. Excellent fuel injection and plating performance, can meet the requirements of high-end smart watches for aesthetic appearance. Plastic parts are small in size but highly accurate. In addition, the left and right sides need to design the slider core pulling mechanism, so the mold design cavity position is 1 out 1. The mold blank is CH2325, the front and back mold core materials are NAK80, which is the best hardness and surface polishing performance of pre-hardened steel. Steel. Designing a 10 o-shaped tiger's mouth at the four corners of the mold core facilitates precise positioning of the front and rear molds. Two conical positioning members 23 are designed on the mold blank for precise positioning of the mold. A locating pin is added between the iron and the movable plate above the mold base and the bottom plate, which is advantageous for maintaining the rigidity of the mold frame. In order to adapt to the patterning habits of Japanese molds, the panel and the bottom plate of the mold are lengthened, so that the direction of the pattern is a horizontal pattern. This patterning method involves pushing the mold horizontally instead of lifting the mold from the top of the injection molding machine. After the molten plastic autonomous flow path enters the parting surface, it enters the mold cavity along the submerged gate of the branching channel, and enters the glue at a certain point. The ejector system of the mold is designed with a ejector pin. The four sets of thimbles are respectively located at the four corners of the plastic part, and each set of thimbles consists of three thimbles of diameters of 0.9, 1.2 and 2.0, respectively. The thimble material is SKH51, which is a high-speed steel heat-resistant thimble. The standard parts of the complete mold are all made of Japanese MISUMI standard parts. The thimble plate is designed with a middle toe to provide guidance for the small diameter thimble.
The bottom of the ejector plate is designed with an ejector insert 26 which increases the rigidity of the ejector plate and prevents deformation of the thimble plate. More importantly, the insert can shorten the ejector stroke. Helps reduce the injection cycle. The sliders on the left and right sides of the mold are all sliders driven by the inclined guide column. Due to the high dimensional accuracy of the side holes of the plastic part, it is necessary to design the insert needle, which is fixed on the slider seat 12 by the slider insert 13. A wear plate is designed on the bottom of the slider to facilitate oil retention and reduce friction coefficient. All inserts are nitrided to increase hardness and reduce wear. The cooling circuit is designed for the stationary mold, which is of great significance for stable injection molding and shortening the injection cycle. For small precision plastic parts such as smart watch cases. Its reasonable injection cycle should be below 20S. The first test injection molding conditions of this set of molds are shown in Figure 4. After the first test, the molds are reviewed according to the appearance of the sample, the dimensions of the plastic parts and the stability of the mold to improve the existing problems.