Soft Tooling-Friendly Inductive Mold Heating—A Novel Concept

Tobias Vieten,André Zimmermann,Andrea Knöller,Wolfgang Eberhardt,Davide Zanin,Thomas Litwin

doi:10.3390/mi12040454

Tobias Vieten, André Zimmermann + Show 4 more

Open Access

https://doi.org/10.3390/mi12040454

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Abstract

In order to economize injection molded prototypes, additive manufacturing of, e.g., curable plastics based tools, can be employed, which is known as soft tooling. However, one disadvantage of such tools is that the variothermal process, which is needed to produce polymeric parts with small features, can lead to a shorter lifespan of the tooling due to its thermally impaired material properties. Here, a novel concept is proposed, which allows to locally heat the mold cavity via induction to circumvent the thermal impairment of the tooling material. The developed fabrication process consists of additive manufacturing of the tooling, PVD coating the mold cavity with an adhesion promoting layer and a seed layer, electroplating of a ferromagnetic metal layer, and finally patterning the metal layer via laser ablation to enhance the quality and efficiency of the energy transfer as well as the longevity by geometric measures. This process chain is investigated on 2D test specimens to find suitable fabrication parameters, backed by adhesion tests as well as environmental and induction tests. The results of these investigations serve as proof of concept and form the base for the investigation of such induction layers in actual soft tooling cavities.

Highlights

IntroductionThe subsequent maskless production steps, such as laser direct structuring (LDS) as well as the wet chemical metallization, enable creating individualized conductive patterns based on laser activatable additives in the thermoplastic materials [1], which can be further functionalized in a final step by different assembly techniques
A method for the soft tooling-friendly heating of cavities for injection molding via induction was proposed
The process chain to produce said tooling consists of additive manufacturing of the inserts, physical vapor deposition (PVD) coating of an adhesion agent and a seed layer, electroplating of the ferromagnetic nickel layer, and laser ablation

Summary

Introduction

The subsequent maskless production steps, such as laser direct structuring (LDS) as well as the wet chemical metallization, enable creating individualized conductive patterns based on laser activatable additives in the thermoplastic materials [1], which can be further functionalized in a final step by different assembly techniques

Methods

Results

Discussion

Conclusion