Direct polymer additive tooling – effect of additive manufactured polymer tools on part material properties for injection moulding

Abstract

Purpose This study aims to investigate the influence of additive manufactured polymer injection moulds on the mechanical properties of moulded parts. Therefore, polymer moulds are used to inject standard specimens to compare material properties to specimens produced using a conventional aluminium tool. Design/methodology/approach PolyJet technology is used to three-dimensional (3D)-print a mould insert in Digital ABS and selective laser sintering (SLS) technology is used to 3D-print a mould insert in polyamide (PA) 3200 GF. A conventionally aluminium milled tool serves as reference. Standard specimens are produced to compare resulting mechanical properties, shrinkage behaviour and morphology. Findings The determined material characteristics of the manufactured prototypes from the additive manufactured tools show differences in terms of mechanical behaviour to those from the aluminium reference tool. The most significant differences are an up to 25 per cent lower tensile elongation and an up to 63 per cent lower elongation at break resulting in an embrittlement of the specimens produced. These differences seem to be mainly due to the different morphological structure caused by the lower thermal conductivity and greater surface roughness of the polymer tools. Research limitations/implications The determined differences in mechanical behaviour can partly be assigned to differences in surface roughness and morphological structure of the resulting parts. The exact extend of either cause, however, cannot be clearly determined. Originality/value This study provides a comparison between the part material properties from conventionally milled aluminium tools and polymer inserts manufactured via additive tooling.

Comparative Analysis of the Impact of Additively Manufactured Polymer Tools on the Fiber Configuration of Injection Molded Long-Fiber-Reinforced Thermoplastics

“…Similar results were achieved by Fernandes et al [30] and Volpato et al [31]. Recent investigations by Kampkar et al [16] proved that the materials still show a rather brittle and non-ductile fracture behavior. However, the deviations can be attributed with high probability to particle agglomeration due to the lower thermal conductivity and a greater surface roughness.…”

Experimental Investigation of Dimensional Precision of Deep Drawn Cups Using Direct Polymer Additive Tooling

“…In contrast to indirect tooling methods, the tools are directly manufactured using polymer additive manufacturing (AM) technologies. While DPAT is a widely researched topic for manufacturing injection molds [4][5][6], it has been almost entirely neglected for the production of deep drawing tools. Most studies addressing the applications of DPAT in the field of sheet metal forming are dealing with bending or embossing operations.…”

Increasing the Sustainability of the Hybrid Mold Technique through Combined Insert Polymeric Material and Additive Manufacturing Method Design

“…Such sustainable AM inserts, containing mold cores and cavities, are inserted in a larger steel overall mold house, which should be adaptable for multiple insert geometries. The method of placing adaptable mold inserts containing the core and cavity of the injection molded product has been referred to as direct polymer additive tooling (DPAT) [11] and hybrid injection molding (HM) [12][13][14][15].…”