Improvement in wall thickness accuracy and smoothness of bore.

Simple to apply as a relatively low-cost retrofit system to any existing gas injection system.
High repeatability and quality of product.


Client Applications

Much of the Research on KoolGas technology has been conducted in the Advance Technology Centre at the University of Warwick using established commercially-available Gas Injection Moulding equipment (AIRMOULD Injection Moulding machine from Battenfeld). The KoolGas equipment is a proven module that is robust for industrial use.

Major Component Moulding companies are currently investigating the application of the KoolGas system in their processes. Process time reductions ensure a rapid pay back on investment in addition to the improved process repeatability and product improvements.

Process Overview

In conventional injection Moulding, heat is conducted throughout the polymer melt region from the hot areas (core of the Moulding) towards the fast cooling areas located at the mould wall. By replacing the hot polymer melt core by a gas using GAIM, the effective wall thickness of the Moulding is reduced. Hence, less time is required to reach the same ejection temperature. In this way, considerable reductions of the process cycle time can be achieved. However, as in conventional injection Moulding, the cooling process of gas-assisted injection moulded articles still controls the overall process cycle time.

KoolGas uses low temperature nitrogen gas to accelerate the cooling rate of GAIM samples by enhancing internal heat transfer from the polymer at the gas channel internal surface.

The KoolGas equipment, installed downstream of the pressure control module, is a specially developed cryogenic heat exchanger, which is used to produce a rapid temperature drop of the nitrogen gas being delivered to the process (Figure 3). The heat exchanger can produce a gas temperature down to -196°C, and withstand pressures up to 350 bar. The out coming gas from the heat exchanger is then conducted through special vacuum insulated delivery system to the gas nozzle inlet, therefore minimising heat losses to the environment. A pressure relieve valve was fitted on the line between the cryogenic heat exchanger and the gas nozzle. In this way, any excessive pressure generated by a liquid-vapour phase change in the system, is rapidly vented safely to atmosphere.