Stereolithography mold life extension using gas‐assisted injection

Abstract

Purpose

The purpose of this work is to extend the life of plastic injection molds made by stereolithography through the use of gas‐assist technology.

Design/methodology/approach

Polypropylene parts were made by injection molding in stereolithography molds with and without gas‐assist technology. The mold life was evaluated by observing the number of parts produced before the breakage of each of small core pins and the ejection force was measured.

Findings

When using gas‐assisted injection molding (GAIM), the core pin life was approximately doubled, the average cavity pressure and the average mold temperature were reduced, and there was a three‐fold increase in ejection force. Also, the core pin location had a very dramatic effect on the life.

Research limitations/implications

This study suggests research into understanding the relationship between ejection force and mold failure, testing the mechanical properties of the parts and identifying reliable design rules for parts produced by GAIM. Research into other low pressure injection techniques and the viability of using a wider set of polymer materials also appears promising.

Practical implications

The result of this research encourages molders who have abandoned the use of stereolithography tools after a few unsuccessful attempts to consider using GAIM with stereolithography molds.

Originality/value

This is a novel use of GAIM technology to extend the lives of molds fabricated by stereolithography.

Citation

Nambiar, R.V., Lee, K.H. and Nagarajan, D. (2007), "Stereolithography mold life extension using gas‐assisted injection", Rapid Prototyping Journal, Vol. 13 No. 2, pp. 92-98. https://doi.org/10.1108/13552540710736777