Air exchanger

• Objective:  Produce the body of an air exchanger by overmoulding structural and insulating expanded polystyrene on top of a complex casing made from ABS injected plastic.
• Challenge:
  • Manufacture a mould for the EPS with identical shape as the future injected plastic piece
  • Take into consideration the complex geometries, the dimensional variables and the shrinkage of the overmoulded piece
  • Facilitate the unmoulding with multi-axis side vents
  • Insure the precise overmoulding of the casing without causing thermal distortion
  • Effectively fill complex maze of obstructions, caused by the overmoulded plastic piece, with the EPS beads
  • Insure the effective fusion of the two different materials
  • Insure the precision of the side drawers’ division lines
  • Make sure the EPS is uniformly stabilized to respect the dimensional integrity and the quality of the finished product
• Solutions:
  • Eliminate uncertainties by running both materials through experimental overmoulding steps
  • Multiple steps mould manufacturing to adjust critical geometrical parameters, based on the overmoulding results
• Result: Polymos finally managed to overmould EPS on a large, complex piece of injected plastic without distortion. The final product combines all the properties of both technologies: external mechanical resistance and efficient thermal insulation.

On September 8^th, 2005, Polymos received the National Bank’s Montérégie SME Gold Award. Thanks to this project, Polymos has been awarded the first prize in innovation by Canada’s plastic industry. The research done for this project has increased Polymos team’s global expertise and this technological advancement is now available for all customers.