Cooling Vacuum Formed Parts

The Problem

A manufacturer of major appliances vacuum forms the plastic interior shell of refrigerators. The deep draw of the plastic and complex geometry left the four corners unacceptably thin. The corners would tear during assembly or bulge when insulation was inserted between the shell and exterior housing, resulting in a high rejection rate.

The Solution

(4) Model 3225 Vortex Tubes were positioned to cool the critical corner areas just prior to forming the plastic sheet. By cooling these areas, less stretching of the plastic occurred, which resulted in thicker corners.

Comment

Rejected parts became very costly, especially when expensive materials and slow process times are involved. The cold air from the Vortex Tube is just the solution for big problems like this one. It can supply “instant” cold air down to -46°C (-50°F) from an ordinary compressed air supply. Along with cooling other vacuum formed parts such as spas, bathtubs, tote pans and waste cans, it is ideal for cooling hot melts, ultrasonic welders, environmental chambers, etc.

This is an ideal application for EXAIR’s EFC, an electronic flow control for compressed air. It reduces air consumption by turning on the compressed air for a preset length of time when sensing the plastic sheet is in position.