Plastic injection mold exhaust on the quality of the mold has a great impact, the mold appears compressed air burns, products within the high internal stress, surface flow and melting lines and other phenomena are related to the mold exhaust, then the plastic injection mold exhaust How to design it?
The role of plastic injection mold exhaust slot has two main points. First, when the injection of molten material, the exclusion of the cavity of the air; the second is to exclude the material in the heating process to produce a variety of gases. The more thin-walled products, the more away from the gate of the site, the opening of the exhaust slot is particularly important. In addition to the small parts or precision parts should also pay attention to the opening of the exhaust slot, because it can avoid the surface of the product burns and injection volume is insufficient, but also can eliminate all kinds of defects in products, reduce mold pollution. In the case of
There are many ways to vent the cavity, but each method must ensure that the exhaust groove is designed to prevent the material from overflowing into the tank while the exhaust is at the same time. Therefore, from the inner surface of the cavity to the outer edge of the mold cavity direction, the length of 6 ~ 12mm above the exhaust groove, the groove height to be about 0.25-0.4mm.
In addition, the number of exhaust slots is too harmful. Because it is dangerous if the mold clamping force in the cavity is not open and the mold cavity is liable to cause cold flow or cracking of the cavity material. In addition to the mold cavity on the side of the exhaust, but also by the pouring system at the end of the flow of the exhaust pipe, as well as leaving the gap around the ejector bar to achieve the purpose of exhaust. In the case of
According to the experience of multi-year injection mold design and product test mode; for complex geometric shape of the product mold, exhaust slot set; preferably after several test mode to determine.
There are several exhaust methods for the overall mold cavity:
1 by the cavity of the slot or insert by the parts;
2 with the side of the insert seams;
3 partially made of spiral shape
4 in the vertical position on the slotted with a slotted heart of the process hole;
5 when the exhaust is very difficult to use mosaic structure, etc., if some die corner is not easy to open the exhaust slot, first of all should not affect the appearance and accuracy of the product under the appropriate mold to change the fight in the fight.