EXTRUSION-ASSISTED DIRECT-FOAMING ROTATIONAL MOLDING PROCESS

摘要

This paper focuses on the evolution and experimental validation of the novel patent-pending Extrusion-Assisted Rotational Foam Molding (EARFM) process intended for the fabrication of high quality integral-skin fine-celled foamed-core polyolefin moldings. The process innovatively conjoins the traditional rotational foam molding technology with extrusion melt compounding in a deliberate attempt to reduce the principal intrinsic disadvantages associated with rotational foam molding, i.e., the energy intensive and very lengthy processing cycles. A lab-scale custom-made heavy-duty experimental setup along with three mold shape variations (cylindrical, flat plate and container-like) have been designed and built. It was used for conducting a comparative experimental process validation by using all three mold designs for processing integral-skin foamed core polyethylene (PE) parts. The process control optimization included resin formulation optimization, direct foaming concept implementation for process simplification, and mold venting system re-design. The thereby modified process resulted in even shorter processing cycle times, lower energy consumption, and improved foam morphologies.