A Novel High Flow Rate Pin for Water-assisted Injection Molding of Plastic Parts with a More Uniform Residual Wall Thickness Distribution

• Published in: International polymer processing Vol. 21; no. 5; pp. 436 - 439
• Main Authors: Liu, S.-J., Wu, Y.-C.
• Format: Journal Article
• Language: English
• Published: De Gruyter 10.05.2022
• ISSN: 0930-777X; 2195-8602
• DOI: 10.3139/217.0989

Three types of water pins are currently used in the water-assisted injection molding technologies to mold plastic parts, including orifice, ring and piercing type pins. Nevertheless, the former two types of pins have the disadvantages of a low flow rate and high pressure drop, while the drawbacks for the latter type are that timing the piercing pin into the cavity is a challenge and the cost of a mold is high. This report describes the development a novel high flow rate water pin for water-assisted injection molding of plastic parts. The pin, which consists of a sintered porous surface outlet, has been tested on parts with two different geometries: a plate with a channel across the center and a float-shaped tube part. The experimental results suggests that the proposed water injection pin can mold parts of a large size with a more uniform residual wall thickness distribution.