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.
_20250310164515A048.webp "Touch Switch Sensor Mold")
Venting of parting surface
Mar 7, 2022The exhaust slot on the parting surface is easy to clean and processing, also not easy to be blocked, and has a good exhaust effect, it is the main area where the gas is exhausted, so the exhaust from...view
Venting insert design of molded parts
Mar 13, 2022In the thin-walled cavity, the end of the melt flow, the bottom of the blind hole of the mold cavity, the end of the solid column of the plastic part, the bottom of the plastic part rib and screw...view
Slider designing tips 1
Aug 3, 20221. After the slider core pulls out, the length of staying in the guide pin slot should not be less than 2/3 of the total length of the slider, for special cases, the slider slot can be partially...view
Design principle of plastic injection mold cooling system
Feb 13, 2022Design principle of cooling system In order to improve the efficiency of the cooling system and make the cavity surface temperature distribution even, the following principles should be followed in...view
The main design points of the design of the plastic mold pouring system
Jan 11, 2022The main runner is the part where the molten plastic first passes when it is sprayed from the injection nozzle, and it is coaxial with the injection nozzle, because of repeated contact and collision...view
Plastic cooling factors by injection parameter
Feb 10, 20221. Plastic parts design: mainly for the wall thickness of plastic products. The thicker thickness of the product, the longer the cooling time. Generally speaking, the cooling time is approximately...view