In the production process of injection molds, it is easy to cause the problem of difficult exhaust, so how to solve it? Mingyang Yutong made the following analysis.
Natural venting of injection molds refers to venting through the part gaps between the molds. Parting surface of injection mold, natural exhaust of push rod and push rod hole matching clearance and movable core hole matching clearance, suitable for most small and medium injection molds.
For example, it is extremely difficult to perform normal exhaust in some special large-scale injection molds. Without affecting the appearance and dimensional accuracy requirements of plastic products, the molding parts of the mold may use inserts or composite structures as much as possible. Different insert splice gaps are formed between different parts of the exhaust. At the same time, the insertion of the mutual structure further reduces the difficulty of processing a single piece, making the mold structure and maintenance very convenient.
The exhaust plug is made of special sintered metal, mainly using sintered material to exhaust in many fine gaps. Sometimes if the end of the cavity filling area is not on the parting surface, if there is no vent fit for its vicinity, it can be embedded deep in the cavity vent, because the vent plug tends to leave contact marks on the surface of the plastic product, Therefore, it is necessary to pay attention to setting the ventilation plug to be hidden in a place where it is not easy to find inside the product. At the same time, the diameter of the ventilation opening should not be too large to avoid deformation of the ventilation plug.
For those common plastic melts that are prone to gas formation, or injection molding in certain parts of thin-walled products, it is often necessary to open a certain number of vent slots on both sides of the core vent. In order to facilitate injection mold manufacturing and cleaning, the surface of the exhaust groove should be opened as far as possible on the side of the mold parting surface. The exhaust groove is generally processed into a curved shape and measured from the edge of the cavity surface, so that the plastic parts can discharge various gases from everywhere, and the speed overflow is also reduced to a certain extent; but the outlet of the exhaust groove should not be set. Open to the operating side of the machine in case of accidental burns caused by high pressure injection of plastic melt.
Post time: Sep-06-2022