Minebea AccessSolutions Technology
Gas assisted molding
ENTRY
This is an applied technology for injection molding, and is a manufacturing method that improves NG events caused by pressure retention by filling inert gas together with the material.
1.Full shot method
After filling the mold with the same amount of material as the cavity volume, fill the mold with high-pressure gas in an amount that compensates for shrinkage during cooling and solidification.
Advantages
Selective gas flow through the thick-walled area efficiently suppresses sink marks.
Disadvantages
・Limited capacity of gas to be filled
・Difficult to spread the gas to the targeted area
Advantages
Selective gas flow through the thick-walled area efficiently suppresses sink marks.
Disadvantages
・Limited capacity of gas to be filled
・Difficult to spread the gas to the targeted area
2.Short shot method
After filling the mold with less material than the cavity volume, the mold is filled with high-pressure gas to expand it.
Advantages
・Thick-walled products can be molded due to the increased hollow ratio.
・Weight reduction compared to solid molding
Disadvantages
・There is a limit to the amount of gas that can be filled.
・Cannot be applied to materials with low elongation
・Hedging occurs, so a pre-cavity (overflow) is necessary to discharge the material that will become the hollow part.
Advantages
・Thick-walled products can be molded due to the increased hollow ratio.
・Weight reduction compared to solid molding
Disadvantages
・There is a limit to the amount of gas that can be filled.
・Cannot be applied to materials with low elongation
・Hedging occurs, so a pre-cavity (overflow) is necessary to discharge the material that will become the hollow part.
