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.
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
The design principle of the exhaust slot
Mar 6, 2022The exhaust system of plastic molds is also very important, if the product has air trapping or exhaust system is not suitable will have a big impact on injection molding production and product...view
Unique Solutions Mold Profile
Dec 27, 2021USM (UNIQUE SOLUTIONS MOLD LIMITED) was founded in 2012 and is located in Dongguan City, Guangdong Province, a famous mold manufacturing province in China, the plant covers an area of 3500 square...view
The sub gate of the plastic injection mold runner system
Jan 26, 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
Comparison of water-assisted and gas-assisted injection molding
May 19, 2022Comparing with water-assisted injection molding technology and gas-assisted injection molding technology, the fundamental difference is the nature of the auxiliary molding media used. One is liquid...view
Parting surface venting of runner system
Mar 10, 2022There are a large amount of gas in the main and sub channel, these gas are discharged through the pull rod (push rod) during injection processing, a part of gas come out from exhaust slot on parting...view