Hybrid Mold: Comparative Study of Rapid and Hard Tooling for Injection Molding Application Using Metal Epoxy Composite (MEC)

Abstract

The mold-making industry is currently facing several challenges, including new competitors in the market as well as the increasing demand for a low volume of precision moldings. The purpose of this research is to appraise a new formulation of Metal Epoxy Composite (MEC) materials as a mold insert. The fabrication of mold inserts using MEC provided commercial opportunities and an alternative rapid tooling method for injection molding application. It is hypothesized that the addition of filler particles such as brass and copper powders would be able to further increase mold performance such as compression strength and thermal properties, which are essential in the production of plastic parts for the new product development. This study involved four phases, which are epoxy matrix design, material properties characterization, mold design, and finally the fabrication of the mold insert. Epoxy resins filled with brass (EB) and copper (EC) powders were mixed separately into 10 wt% until 30 wt% of the mass composition ratio. Control factors such as degassing time, curing temperature, and mixing time to increase physical and mechanical properties were optimized using the Response Surface Method (RSM). The study provided optimum parameters for mixing epoxy resin with fillers, where the degassing time was found to be the critical factor with 35.91%, followed by curing temperature with 3.53% and mixing time with 2.08%. The mold inserts were fabricated for EB and EC at 30 wt% based on the optimization outcome from RSM and statistical ANOVA results. It was also revealed that the EC mold insert offers better cycle time compared to EB mold insert material.

Analysis of the main factors affecting mass production in the plastic molding process by using the finite element method

“…Mass production by using the method of mass tooling involved with mold insert provided the alternative and effective way and offers better accuracy. Some shortcomings like alignment, pressure distribution need to be addressed as explained in [11].…”

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].…”

“…Currently, most prototype injection molds are still made via hard tooling options, for which aluminum is often chosen as mold material [16,17]. In the last two decades, HM has been already introduced more broadly in industry [15]. This sustainable manufacturing method generally includes inserts made by all rapid tooling (RT) techniques and is thus not limited to AM [12].…”

“…This sustainable manufacturing method generally includes inserts made by all rapid tooling (RT) techniques and is thus not limited to AM [12]. For example, silicone casting is an RT technique often investigated for injection mold tooling [12,15]. The high speed machining (HSM) of soft metals such as aluminum can also be applied for HM insert production [18].…”

Epoxy-Copper Composite Materials for Injection Mold Optimal Design: a Low-Run Production Simulative Study

“…Many of these studies describe the mechanical and thermal behavior of these molds for different resin fillings, such as carbon fibers, pulverized aluminum, and ceramic, among others (Ma et al 2007;Vasconcelos et al 2006). It is demonstrated that the addition of fillers as copper in an epoxy resin matrix is able to improve the mold performance in terms of mechanical and thermal properties (Hussin et al 2021). However, no previous study has been found in which the mold is reinforced with long fibers in certain directions; generally, these are particulate materials or short fibers.…”