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 "Visual Doorbell Housing Mold")
Plastic part ribs desigining
Jan 4, 2022The ribs function: The role of ribs is to improve the strength and rigidity of the plastic parts, prevent the plastic parts from being distorted and deformed, and will not cause the appearance of 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
Key points of gas-assisted injection molding process
Apr 20, 2022Gas injection parameters The gas-assisted control part is a device that controls the gas pressure in each stage, the gas-assisted parameters have only two values: gas injection time (seconds) and gas...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
Limitations of gas-assisted injection molding technology
Apr 25, 2022Gas-assisted injection molding technology has obvious advantages in thick wall thickness and pipe parts, but this technology still has many limitations, which are mainly reflected in the following...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