• 2023-07-31
• 805
• 5 Comments

What factors affect the structure of the mold

What factors affect the structure of plastic mold processing

1. Cavity layout.

According to the geometric structure characteristics of plastic parts, dimensional accuracy requirements, batch size, mold manufacturing difficulty, mold cost and so on to determine the number of cavity and its arrangement.

For the injection mold, the precision of the plastic parts is 3 and 3a, the weight is 5 grams, the hardening gating system is used, and the number of cavities is 4-6; The plastic parts are of general accuracy (4-5 grade), the molding material is local crystalline material, and the number of cavities can be 16-20; The weight of the plastic parts is 12-16 grams, and the number of cavities is 8-12; The weight of 50-100 grams of plastic parts, the number of cavities to take 4-8.

The recommended number of cavities for amorphous plastic parts is 24-48,16-32 and 6-10. When the weight of plastic parts continues to increase, multi-cavity molds are rarely used. For plastic parts of grade 7-9 accuracy, the maximum number of cavities is increased to 50% compared with the plastics of grade 4-5 accuracy indicated.

2. Determine the parting surface.

The position of the parting surface should be conducive to mold processing, exhaust, release and molding operations, and the surface quality of plastic parts.

3. Determine the pouring system (shape, position and size of main runner, sub-runner and gate) and exhaust system (exhaust method, exhaust groove location and size).

4. Select the ejecting method (ejecting rod, ejecting tube, pushing plate, combined ejecting), decide the side concave treatment method and core pulling method.

5. Determine the cooling and heating methods, the shape and position of the heating and cooling groove, and the installation position of the heating element.

6. According to the mold material, strength calculation or experience data, determine the thickness and outline size of the mold parts, outline structure and the location of all connections, positioning and guiding parts.

7. Determine the structure of the main forming parts and structural parts.

8. Consider the strength of each part of the mold and calculate the working size of the molded parts. If the above problems are solved, the structural form of the mold will naturally be solved. At this time, you should start to draw a sketch of the mold structure to prepare for the formal drawing.