Session: 03-03-03: Annual Congress-Wide Symposium on Additive Manufacturing III

Paper Number: 166705

Investigating the Effects of Printing Orientation on Material Properties of 3D Printed Resin for Humanoid Robot Applications 

Resin printing is a relatively new tool with many questions still unanswered. With this in mind, the following paper is focused on the material properties of resin and what factors can affect these numbers. The motive for this research comes from the Humanoid Robot project, led by students at Worcester Polytechnic Institute (WPI). This group was using Esun Hard-Tough resin as the material for the robot body, and unexpected issues arose from the resin printed parts, mostly breaks and fractures after few uses. This paper’s research was then conducted to collect data on how to maximize the material qualities, and what its limits are. In the previous year of this Humanoid Robot project (2023-24), another conference paper was published called “Properties of 3D Printing Resins For Humanoid Robot Application”. It looked at 6 different types of engineering resins as tensile testing was conducted with type IV specimens, sliced at a 30 degree orientation on the build plate. Its purpose was to select the resin best suited for the project, and it was the foundation of this study. 

This topic requires more research to glean what usual resin behavior is like, what should be expected of it, how printing orientation affects performance, and general material properties so simulations can be conducted in software, such as ANSYS in this study, for reliable expectations of designs. In order to do this, a few key procedures were used, these were tensile testing, ANSYS simulations, and fatigue testing. Tensile testing was done on a Mecmesin MultiTest 2.5 dv(u), 2500N calibrated load cell attached. Type IV specimens were used, all cured for the same amount of time and tested 1-2 days after curing. The difference between the samples were the orientation on the Elegoo Jupiter build plate, the angles were 20, 30, 45, and 60. The material properties obtained from these tests were implemented in a custom material in ANSYS and a simulation similar to tensile testing was set to compare results for discrepancies. Fatigue testing was conducted for better simulation results. Knowing how many cycles a certain part will be expected to last is highly valuable during the design iteration process. The findings from these tests showed small behavior changes at different printing orientations, and lower fatigue resistance that had been expected. This data and research can be utilized by other researchers to further learn about the intricacies of resin printing. Continuous testing and data acquisition of this material is critical for assessing in which scenarios resin printing is the best option and fits requirements.

Presenting Author: Ligia Portugal Worcester Polytechnic Institute

Presenting Author Biography: Ligia Portugal is a mechanical engineer who graduated in May 2025, from Worcester Polytechnic Institute (WPI). Portugal was born in Brazil and moved to the United States at age 13, where she developed an admiration for robotics and engineering through school clubs. This admiration is what drove her to WPI and guided her academic path. She is excited to start gaining experience in her field from her first job and continue her contributions in research and development.

Authors:

Ligia Portugal Worcester Polytechnic Institute
Pradeep Radhakrishnan Worcester Polytechnic Institute