Session: 02-02-02: Characterization of Additively Manufactured Metal Parts

Paper Number: 69263

Start Time: Wednesday, 02:00 PM

69263 - Effects of Laser Parameters on Printing Quality of Injection Mold Cores 

With the constant enhancement of living standards, personalization and diversification have gradually become the mainstream consumer demand. Mass customized products have become the future trend, with low cost, high efficiency and high design freedom as the key features. It’s well known that injection molding has been widely utilized to fabricate light-weight, complex-structured precision plastic products in a cost-effective and mass-productive way. However, due to the long manufacturing cycle and high cost for the entire mold set, it’s unsuitable for personalized and small batch production. Meanwhile, the rapid development of 3D printing makes it possible to freely design and manufacture products, providing technical conditions for personalized customization. In particular, the selective laser melting (SLM), one of 3D printing technologies, is able to manufacture metal parts with complex shapes and good mechanical properties. In this context, the present work aims at investigating the feasibility of product mass customization according to consumers’ needs, making full use of advantages of both SLM and injection molding. However, the integration of the two processes is not easy. One reason is that the injection mold set is very precise, which requires the printed cores to be precise enough to ensure good matching. Another reason is that as SLM technology is based on melting and solidifying metal powders on substrates, the printed metal mold core needs a series of post-treatments to be combined with the injection mold set, for example, wire cutting is needed to separate the printed core from the substrate. Obviously, too complex post-treatments will increase the manufacturing cycle and cost, which weakens the advantages of process integration. Therefore, one key issue is to reduce to the largest extent (or even totally avoid) the post-treatments of the printed core. This may be realized by optimizing core structure designs and laser parameters. For this purpose, the injection mold cores were manufactured by SLM and then assembled into the injection mold set. Specifically, a new type of cylindrical injection mold core with a diameter of 30 mm was designed. In this core, ear structures for assembly purpose were designed with different inclined angles (i.e., 45°, 60° and 75°). All structures were 3D printed using the SLM machine (Solutions SLM 125), and the influence of the ear inclined angle on the fitting degree was evaluated. In addition, by adjusting the laser scanning strategy/parameters, the optimized mold core was successfully manufactured, which can be directly integrated into the injection mold set. It’s found that the fitting degree of the 3D printed core and the injection mold set is directly proportional to the inclined angle of the ear structures. Meanwhile, the fringe laser scanning strategy gives the smoothest surface of the printed cores. For example, the roughness values for the top and lateral surfaces are 11 and 6 microns, respectively. As fully integrating the individualization of SLM and the batch production capacity of injection molding, this work will provide theoretical and experimental data support for the mass customization.

Presenting Author: Can Yang Shenzhen Technology University

Authors:

Can Yang Shenzhen Technology University
Bao-Hua Yang Shenzhen Technology University
Chunbo Li Shenzhen Technology University
Liang Deng Shenzhen Technology University
Ren-Xiu Yang Shenzhen Technology University