3D Printing of Variable Durometer Vibration Isolators

Project Goal: Develop a process that produces continuously variable hardness of material during the 3D printing of a vibration isolator.

Printing plastic with continuously varying hardness has potential applications in the design of vibration isolators. Current designs involve rubber isolators and metal mounts, but the bonding seams between metal and rubber tend to separate after prolonged use, increasing the failure rate of the isolator. A new process makes it possible to create a single-piece vibration isolator that has a lower failure rate than those currently produced. Also, isolators printed with adjustable hardness allow for fine-tuning the isolator to be more effective at specific frequencies.

The printhead of the MakerGear M3-SE 3D was modified to include a three-inlet nozzle with one outlet and supporting hardware that allows simultaneous mixing of high-, medium- and low-hardness filaments. In the custom design, the filaments are fed into the hotend at different rates to vary the mixture, and therefore the hardness, of the extruded material. In the printing process, the user creates a G-code file using slicer software. The file is run through a custom post-processor, and then this code is sent to the printer. The custom G-code contains commands that change printed plastic hardness depending on print-head coordinates throughout the process.

The combination of the modified printer and the custom software enables printing parts with continuously variable plastic hardness.