Additive Manufacturing Strategies

3D Printing Studied as a Way to Produce Tooling for Injection Molding

ST Medical Devices

Share this Article

Injection molding is one of the more traditional manufacturing technologies that 3D printing is striving to replace – at least in some applications. 3D printing will likely never fully replace it, but will rather be used alongside it as a complementary technology. Already 3D printing has shown its value to injection molding as a cheaper, faster way to create tooling, for example. In a thesis entitled “Tooling for Injection Molding Using Laser-Powder Bed Fusion,” a University of Louisville student named Mohith Ram Buxani takes a closer look at using 3D printing to create tooling for injection molding.

The injection molding industry has always suffered from high costs and long lead times for tool making. 3D printing is an alternative method of creating tooling, saving time and money.

“There are various studies that approach the 3D printing route for the fabrication of tooling for injection molding,” says Buxani. “Additionally, there are studies that involve the use of simulations for the evaluation of part-design. However, there were minimal studies found that integrated these perspectives together and evaluated the performance of L-PBF (laser-powder bed fusion) fabricated molds. Therefore, this study has taken on the challenge of integrating the individual expertise of each industry to create a supply chain collaboration.”

Buxani’s research group 3D printed multiple tools for injection molding using a variety of materials and machines that achieved good mechanical properties. The study focuses on evaluating L-PBF fabricated molds using experiments and simulations examining several categories: post-machining, part design, material design and conformal cooling channels. The first part of the study uses injection molding experiments and computer aided simulations to understand the effects of single-sided L-PBF fabricated mold cavities on injection molded part quality and molding material composition. The next part of the study uses experiments and simulations to evaluate L-PBF fabricated core-and-cavity tooling with conformal cooling channels.

In the first part of the study, a mold cavity was selected in the form of an elliptical-shaped keychain. 17-4 PH stainless steel was used to 3D print the mold. Trials were run with the a version of the mold as printed, as well as one that had been machined, using both physical injection molding processes and computer simulations. The injection molded parts were greatly improved using the machined mold. The experiments also concluded that parts with thin walls tend to cool more quickly and achieve better part quality in terms of sink marks and warpage. The location of sink marks and warpage could be accurately predicted in computer-aided simulations, but their magnitude was not well described.

Another conclusion was that 3D printed molds can help identify improvements in part design, material composition of polymers, and simulation methods more quickly than traditionally manufactured molds.

In the second set of experiments, conformal cooling channels were 3D printed into the tools.

“In traditional manufacturing, conventional cooling channels are straight-hole passages built into the injection mold insert to decrease cooling time and increase temperature uniformity for part quality,” Buxani states. “However, design constraints in traditional manufacturing do not always allow conventional cooling channels to cool down a complex part uniformly.”

Additive manufacturing enables the production of mold inserts with conformal cooling channels, which are cooling passage holes that follow the part’s geometry, cooling the part in a much more uniform manner. The research team 3D printed two cavity-side molds with conformal cooling channels at different depths: 8 mm and 4 mm. These molds were evaluated using experiments and mold-filling simulations. The simulations indicated that the conformal cooling channel design influenced the surface temperature distribution of the part. However, simulations indicated no alleviation by conformal cooling channels in the center temperature of the thickest region. There was not a significant difference in part quality or cooling with the incorporation of conformal cooling channels for these particular mold designs; additional designs need to be tested.

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below. 

 

Share this Article


Recent News

FDM 3D Printing Support Removal Times Cut in Half with VORSA 500

3D Printing Drone Swarms, Part 12: 3D Printing Missiles



Categories

3D Design

3D Printed Art

3D Printed Food

3D Printed Guns


You May Also Like

ICAM 2021: Keynotes on 3D Printing in Healthcare & Aerospace

At last month’s International Conference on Additive Manufacturing (ICAM) 2021 in Anaheim, California, hosted by ASTM International’s Additive Manufacturing Center of Excellence (AMCOE), a wide variety of topics were covered,...

Featured

3D Printing Unicorns: Gelato Gets $240M in Funding, Expands into 3D Printing

On-demand printing platform Gelato, based in Oslo, Norway, achieved the coveted unicorn status after a new funding round. On August 16, 2021, the company announced it had raised $240 million...

Featured

US Army and Raytheon to Use 3D Systems Metal 3D Printing to Heat-Optimize Munitions

3D Systems (NYSE: DDD) has been chosen by defense contractor Raytheon and the U.S. Army’s central laboratory to help with a design optimization project. To do that, the 3D Systems’...

Raytheon Receives Funding for Aerospace 3D Printing of Optical Components

This spring, Ohio-based America Makes, the leading collaborative partner in additive technology research, discovery, and innovation for the US, announced its latest Project Call for AXIOM, or  Additive for eXtreme Improvement...


Shop

View our broad assortment of in house and third party products.