Why should the injection mold exhaust and its way

When the plastic melt is injected into the cavity of the injection mold, if the original gas and steam in the cavity can not be discharged, the pores will be formed on the products, the joints and the appearance of the outline are unclear, and the cavity can not be completely filled. At the same time, the high temperature burns the parts due to the compression of the gas, so that the coke marks will be produced. The compressed gas in the injection cavity will reduce the filling speed and affect the injection cycle and product quality. So the design of injection mold must consider the exhaust problem.

Injection mold exhaust mode:

Way one: the exhaust in the flow passage is generally set at the end of the flow passage, because it is the last place full of exhaust groove depth can take 0.025 ~ 0.10mm, width can take 1.5 ~ 6mm. The effective stroke of 2~5mm can be opened bevel, convenient for more efficient exhaust.

Method two: The use of injection mold thimble exhaust, thimble and insert with a certain gap, you can use this gap to achieve the purpose of exhaust.

Method three: Design the integral injection mold into an insert mold. Exhaust gas using the gap between inserts. After the trapped gas location is assessed according to the mold flow analysis software or experience, the area is designed as a Mosaic structure to achieve the exhaust purpose.

Way four: We can also use exhaust steel to process injection molds. Design the exhaust steel in the mold where the gas is trapped to reach the purpose of exhaust. This is a relatively novel exhaust method at present.

Way five: There is another way is vacuum exhaust, that is, mold vacuum, at the same time, this can also promote plastic mold filling, but this increases the complexity of injection mold, so it is rarely used.

The exhaust of injection mold is an important problem in mold design, especially in rapid injection molding, the exhaust of injection mold is more strict. From the distribution of bubbles in plastic parts, we can not only judge the nature of bubbles, but also judge whether the exhaust part of the mold is correct and reliable. The mission of Fanstar is to master the core technology of injection molding production, communicate and analyze the technology before mold production with customers from the production needs of finished products, so that the mold delivery time is short, the life is long, the mass production is fast and the finished product quality is excellent!