Gas assisted injection moulding process now has another modification; wherein Carbon Dioxide (CO₂) is introduced in melt through injection cylinder in addition to the mould.

The Amotech process developed by Asahi Kasei Corporation, Japan involves injection of CO₂ gas at about 2-3% level and at 5-10Mpa pressure in injection cylinder.

CO₂ gas acts as plasticizer and enhances flow of the melt:

CO₂ gas gets dissolved throughout the melt and gets dispersed in the atmosphere at a later stage. The structural integrity of the moulded part therefore does not get affected. The major benefits are superior surface finish and perhapssome scope of reduction in wall thickness of the moulded parts.

The process has been evaluated in Polystyrene and Acrylic polymers in injection moulding machines upto the size of 500-ton capacity. Most of the gas disappears from the moulded parts within a day. No gas is detected at all on storage of the products after a week.

Target applications are:

	Lenses
	Optical discs
	Portable information terminals

The Amotech process is available for license and could cost under $50,000. This cost includes gas supply equipment and special screw that introduces gas in the melt.

It will take some time to assess the success of this new technology.