Electrical protective cover product is shown in Figure 1. Material is PC+ABS, and shrinkage rate is 5 ‰. PC/ABS is a modified engineering plastic synthesized through mixing, commonly known as plastic alloy. Among them, PC plastic raw material is polycarbonate, and ABS is a copolymer of acrylonitrile (A), butadiene (B) and styrene (S). This kind of modified plastic has better performance than simple PC and ABS, such as: improved impact resistance, heat resistance, hardness and so on.

 

Figure 1-1 Product Picture of Protective Cover
PC/ABS plastic raw materials, as the world's largest commercial polymer alloy with the largest sales volume, have been growing at a demand rate of about 10% in recent years. Compared with PC, PC/ABS has improved fluidity, improved processing performance, and reduced sensitivity of products to stress. Therefore, it is widely used in high-strength, high-heat-resistant parts such as automotive interiors, exteriors, and car lights.

 

Figure 1-2 Product Picture of Protective Cover
As people's awareness of environmental protection has increased, environmental protection and recyclable regulations such as ELV in automotive industry have been promulgated one after another, and raw material manufacturers have continued to provide new solutions. Electrical protective cover products just take advantage of high impact resistance of PC/ABS. It can be seen from product picture that product size is inch, size is larger, outer surface is appearance surface, and no trace of glue is allowed, so structure of flip chip mold is selected.

 

Figure 1-3 Product Picture of Protective Cover

1. Design diagram of protective cover mold is shown in Figure 2-1 and 2-2. In order to avoid feeding marks on the surface of plastic parts and ensure uniform feeding, mold adopts an inverted structure, glue is directly fed in with a large nozzle, and gate is removed after molding.
2. Selection of parting surface of product is shown in mold drawing. Product size is larger, and ranking is 1 cavity.
3. Mold belongs to mold exported to United States. Mold design concept adopts mold design concept of North America as a whole. Mold base is a straight mold base with no panel on the top.
4. 3 lifters of movable mold adopt a three-section stick design. This is standard lifter structure of PCS, a famous American manufacturer of standard parts. Return position of lifter is designed with a travel switch.

 

Figure 2-1 Mould of protective cover
5. In order to ensure accuracy of dynamic and fixed mold clamping, 4 precision positioning side locks are designed on four sides of mold base, which are installed by mold base manufacturer to guide mold.
6. A runner bushing is designed in the center of mold to facilitate passage of extended nozzle of injection molding machine, at the same time provide support for fixed mold and play role of supporting head.

 

Figure 2-2 Mould of protective cover

7. Movable and fixed mold core is designed with sufficient water transportation to ensure cooling effect. Water transportation diagram of protective cover mold is shown in Figure 3.

 

Figure 3 Water transportation diagram of protective cover mold

8. Exhaust inserts are designed for bone position of movable mold, which simplifies processing. Movable mold insert diagram of protective cover mold is shown in Figure 4.

 

Figure 4 Movable mold insert of protective cover mold
9. Return position of flip chip ejection system is mostly ejected by a hydraulic cylinder. Molds exported to United States generally use two brand cylinders, PARKER and MILLER. In order to ensure balance of ejection, two ejection cylinders on both sides of mold need to be balanced in oil intake, that is, design of a centralized oil inlet block ensures that pipeline lengths of the two cylinders are equal and oil intake is balanced.
10. Due to presence of oil cylinders on both sides, support legs are designed for stable placement of mold, see photo.

 

Figure 5 Photo 1 of protective cover mold

11. Export mold needs to design a clamping piece to ensure that mold will not open parting surface during transportation to avoid damage. Clamping piece is shown in yellow part in Figure 7. Thimble plate should also be designed with a fixing device to prevent it from moving during transportation and damaging cavity, as shown in the photo in Figure 5.

 

Figure 6 Photo 2 of protective cover mold

12. In addition to 3 lifters, flat thimble and dome pin are also designed for ejection of plastic parts. Flat thimble is arranged at the bottom of bone position. Flat thimble of mold exported to United States needs to be plated with titanium to increase wear resistance.

 

Figure 7 Photo 3 of protective cover mold

This protective cover belongs to a large-scale production mold. Customer has already opened a set of molds. One set of molds cannot meet production needs in terms of life and production efficiency. Therefore, customer decided to open a second set of molds. It is reasonable and fully meets requirements of mass production. It can be used as a reference when designing similar molds.