Design Principles of Straight Top Block and Thimble for Automobile Mould

Ⅰ. The design principles of the straight top block for the automobile mould

1. The mating length of the straight top link and the guide sleeve must be greater than 2/3 of the length of the link in the B plate;

2. The straight top block is connected with the link rod, and it is better to fix it with cup-head screws, which is convenient for processing; it can also be fixed with a pin or a press block;

3. The edge of the screw hole on the top block is at least 5mm away from the sealing position;

4. The hole between the connecting rod and the B plate should be 0.5mm away from one side;

5. The head and tail of the link should be considered for positioning; the bottom plate should be made with craft holes for easy disassembly and assembly.

6. The link can be directly fixed on the bottom needle plate;

7. The side of the straight top block of the automobile mould needs to be inclined by 3 or 5 degrees to avoid friction with the mold core when ejecting;

8. There should be a distance of 0.2～0.3mm between the straight top block and the inner side of the plastic product.

Ⅱ. The design principles of the thimble for the automobile mould

1. According to the characteristics of industrial moulds: the depth of the column is less than 5mm for inserting needles, and the pillars greater than 5mm are used for cylinders, but also according to the actual situation;

2. Deeper bones need to be made of inserts for exhaust to avoid air trapping during injection molding and unsatisfactory filling of the bones;

3. Place a nozzle needle directly under the main runner and make an inverted buckle to pull the runner out of the runner after the mold is opened;

4. Arrange the thimble reasonably according to the principle of product balance ejection. The diameter of the thimble of the automobile mold should be as large as possible, and it is more difficult to process the smaller thimble.