Key points of injection mould design for hot nozzle of mobile phone shell
The mobile phone shell product is shown in Figure 1. The maximum size of the product is 97.62 mm x 43.76mm x 11.80 mm, the average thickness of the plastic part is 1.10 mm, the material of the plastic part is ABS+PC, the shrinkage rate is 1.006, and the quality of the plastic part is 5.80 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 mobile phone shell is composed of upper and lower shells. After the upper and lower shells are assembled, the joint surface is required to be smooth and not scratchy, and the appearance is beautiful. The mobile phone shell is a very demanding plastic part with high appearance, which has high requirements on the mold. The plastic part of the mobile phone shell is made of ABS+PC, commonly known as plastic alloy, which has high toughness and strength, as well as good injection performance. The most important thing is the plastic alloy products, which will not crack when dropped on the ground, which can meet the requirements of mobile phone products.
According to the accuracy requirements of the mobile phone case, the mold design cavity rank is 1 out 1. The mold base is the standard mold base CI2330, and the cavity rank is 1 out 1 not because the production batch of the mobile phone case is small, but the accuracy is determined . The mold design drawing is shown in Figure 2. The gate position of the mobile phone shell is selected in the middle of the two windows on the top surface of the shell, and a single hot nozzle is used to inject the glue at one point. After the plastic part is assembled, the gate position is covered by the lens, which will not affect the appearance of the plastic part.
There are 4 hooks for assembling on the edge of the plastic part. See the attached 3D drawing. It is necessary to design the movable mold slider. There are 3 undercuts on the inner side, which need to be designed for oblique ejection. Because the movable die slide is very small, a barb is designed on the slide to replace the inclined guide post. The three inclined roofs all adopt the inclined roof of MLM sub-structure. The minimum pin diameter here is ø4. There is a key point in the mold design, the middle insert of the movable mold (the blue insert), the insert must be designed here and cannot be made into the original structure. Because the original body is left, electrical discharge processing is required, which will make the edges of the plastic parts of the mold not clear enough, and it is difficult to vent during injection molding.
The movable and fixed molds are designed with sufficient cooling water. The fixed mold has a set of water-carrying IN5 and OUT5 close to the parting surface. This group of water-carrying water needs to be connected to hot oil during injection molding in order to increase the cavity mold temperature and improve the appearance quality of the plastic parts. , To avoid welding marks outside each button hole. The hot oil has a high temperature, and a long throat nozzle is required to be directly connected to the mold core, and it is not suitable to use a rubber ring to seal.
The ejector of the plastic parts adopts a thimble and a cylinder. Because the diameter of the cylinder is small and there are 3 inclined tops, the ejector plate of the mold must be guided by the center to avoid the failure of the ejection mechanism. An inclined top guide block is also designed on the bottom surface of the B board.
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