Building a DIY Drop Tower for Impact Testing Resin 3D Prints

I've been working on a custom Drop Tower (impact tester) to accurately measure the dynamic impact strength of 3D-printed resin structures (specifically cubes with various internal infills). Here is a quick build log of the mechanical stage!

The Mechanical Design The main frame is built using V-slot and T-slot aluminum extrusions, held together by robust 3D printed brackets. The impact mechanism relies on a massive steel cylinder with a flat face, riding on linear bearings along two vertical guide rods. To lift it, I'm using a stepper motor coupled with a lead screw located at the back, which raises an electromagnet. Once it reaches the desired height, the electromagnet releases the steel cylinder, delivering a precise amount of kinetic energy to the sample below.

The Problem: The Anvil & Stoppers When testing 20% infill resin samples, the base holding the sample needs to be absolutely rigid. I also wanted a way to precisely limit the crush depth (e.g., forcing the impactor to stop exactly at 8mm of deformation). I designed a custom base with mounting tabs for solid ABS stopper rings. The ABS stopper is much bulkier and stronger than the tiny resin sample, effectively halting the massive steel cylinder.

The Solution: Titanium CNC Machining 3D printing the base wasn't an option, and standard aluminum would dent over time. I decided to go all out and have this custom anvil CNC machined out of Titanium.

A massive shoutout to Justway for sponsoring this part of the build! I sent them the CAD files, and their CNC service delivered this flawless titanium base. If you are building extreme hybrid projects and need serious metals like titanium machined, I highly recommend checking them out.

The mechanics are now fully done. Next step: finishing the electronics. Stay tuned!