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.
Side gate of plastic injection mold runner system design
Jan 23, 2022In order to get the best injection quality, the gate type must be selected carefully, the coommon gate tyeps are: direct gate, side gate, pin-point gate, sub gate,valve gate of hot runner etc. Among...view
Slider of side core pulling mechanisum assembling
Jul 21, 2022The picture 1 shows a typical guide pin driven slider parting and core-pulling mechanism, we will talk about the composition and function of the lateral core-pulling mechanism. 1. Lateral forming...view
The difference between full shot and short shot of gas-assisted injection molding
Apr 13, 2022Gas-assisted injection molding can be divided into short shot and full shot. Short shot The short shot method is shown in picture 1, it is suitable for thick-walled plastic parts with low mold filling...view
Design Tips of Vacuum Venting Mold
Mar 30, 2022There are some regular venting way which are parting surface venting, insert venting, insert pin venting and well-ventilated steel, but there is a special way is vacumm venting, it will need vacumm...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
USM Blogo Opening
Oct 27, 2021Hello everyone! Our blog is open today, it is very glad to have the opportunity to meet you here, welcome to visit us whenever you need. USM is a professional plastic injection mold and molding...view