The main points of the design of the injection mould of the electric toothbrush body
The electric toothbrush body mold is shown in Figure 1. The maximum size of the product is ?42.25 mm x 138.20 mm, the average thickness of the plastic part is 2.65 mm, the material of the plastic part is PP, the shrinkage rate is 1.016, and the quality of the plastic part is 22.62 grams. The technical requirements of 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 difficulty of mold design is that the shape of the plastic part needs to be designed with a Hough slider core, and the gap between the two sliders must be controlled below 0.03.
It can be seen from Figure 1 that there are several holes on the shoulder of the plastic part for button holes, and the head is for through holes to facilitate the passage of the rotating shaft. The inner cavity of the plastic part is an operating system component or an electronic component, and the outer diameter of the large port has an external thread. The battery cover is assembled here.
According to the structure of the plastic part, the structure of the Huff slider here needs to be designed as a front mold oblique elastic slider structure. The mold cavity is ranked 1 out of 2, and the molten plastic enters the runner of the Huff slider directly from the sprue sleeve 25. Then enter the top of the plastic part by means of a point gate.
Slender cylindrical parts, such as electric toothbrush bodies and penholders, have a greater tightening force on the core. Directly pushing out will cause the plastic parts to bend and affect the straightness, and the plastic parts will become unqualified products. The main measure to solve this kind of plastic part deformation is to demold the movable and fixed molds together. After the mold is opened, the Huff slider does not separate immediately, but loosens a certain distance from the movable mold insert 30 that wraps the plastic part, continues to open the mold, the buckle machine opens, the hook pulls the auxiliary front mold oblique elastic slider to open, The driving force of the block is a spring. Finally, the top rod 27 pushes the push plate insert 5 to demold the plastic part.
The control mechanism of the first sequence classification is the buckle machine, the spring 8, and the limit of the push plate is realized by the long limit screw fixed on the B plate. The delayed parting mechanism of the front mold oblique elastic slider effectively decomposes the packing force and avoids the deformation of the plastic part during the ejection process.
