Processes based on injection molding but more complex – for specific applications.

Co-injection

Insert Molding

Gas Assist Injection Molding

Water assisted Injection Molding

Micromolding

In-mould decoration

Advances In Injection Molding Technologies

Gas Assist Injection Molding

The process step involves: 1. The process begins when a "short shot" of thermoplastic is injected

into a mold, partially filling it with a predetermined amount of resin.

2. Using either a nozzle or gas pins, nitrogen is injected into the center of the hot resin. Following the path of least resistance it forms hollow channels and directs the resin to the last area of the mold to fill. 3. As the gas expands in the cavity, forcing the plastic in front of it, all of the surfaces receive an equal pressure creating an even "pack out" of the part. This brings the following benefits: shortened cooling cycle, improved dimensional stability. 4. The nitrogen gas is vented either through a sprue break, if gas was injected through the nozzle, or back through the self-venting pins if injected by pins.

Principle of Gas/Water Assist Injection Molding

Application – Gas Assist Injection Molding

Material savings (weight, cost) for thick-walled parts up to 40%.

Cycle times may be reduced by 50% or more when compared to

standard injection molding of thick-walled parts.

Improved holding pressure effect.

Uniform shrinkage and pressure.

Design freedom.

Fewer weld lines due to fewer injection points.

Advantages: