English
русский
The main reasons for air trapping of plastic injecton mold
During the injection molding process, the front end of the slight ribs may be air trapped and plastic burnt, and also cause the molded part may become black and carbonized.
The mechanism of air trapped scorching is that when the air in the mold cavity is extruded by the molten plastic flowing into the cavity, the air will heat due to being compressed if it is in a sealing state without an outlet, and then it leads to combustion and burns.
Since the air is a kind of gas, it can be compressed, but it generates heat when compressed, it is like when we use a pump to inflate our bike tires, the pump gets hot.
The compression of the residual air in the cavity usually occurs in a short time of about 0.1 to 0.5 seconds, because it is compressed under a high pressure of 200 to 500 kgf per square centimeter, it is easy to heat up to the ignition point of the plastic (as shown in picture 1).
Therefore, for some slight ribs, pillars and other product features in the gas injection mold, it is necessary to make venting slot to let the gas in the mold which can be discharged to the outside of the cavity.
Factors affecting the cooling rate of parts by injection molding
Feb 9, 2022It should be shaped by cooling to get stable plastic part after plastic filling the cavity and core side, so most injection molds need to be equipped with cooling devices to make the mold temperature...view
Slider designing tips 2
Nov 22, 20239. The molding parting surface of the slider molding should be made as a shut-off surface as possible, and the width of the shut-off part should be at least 8mm, and do not make a shut-off surface;...view
Temperature system of injection mold
Feb 8, 2022Hi everyone,the mold cooling time is the longest during injection, so the design of mold temperature system controlling is very important, we will talk about mold cooling, heating system in following...view
Design principles of plastic injection mold runner system
Jan 6, 20221. Quality first The design of the gating system has a big influence on part quality, firstly the gate should be set at the easiest part of the plastic part to be removed, and at the same time, the...view
Plastic injection mold runner system design
Jan 16, 2022The gate is the connecting part between the runner and the cavity, and is also the end part of the injection mold gating system, the molten plastic enters the cavity and core side through the gate...view
Plastic injection mold cooling system design notice
Feb 14, 2022Design notice of designing the cooling system: 1. Normal molds can be quickly cooled to obtain a shorter molding cycle, and precision molds can be slowly cooled with a mold temperature thermometer; 2....view