Three years ago, I started to build the Blackbox 3D Printer. There was one driving factor which kept me going: my dream of making soft robots one day. I assembled pneumatic robots in 2017, and that convinced me that I was on the right track. The assembly of these robots was complicated because of the numerous hard to reach parts, the required precision, and complex assemblies. That way, we'll never build robots like the ones we dream of. My concept is to use a multi-material printer that can produce the most sophisticated features in one process. And today I finally got a proof of concept!
How it works
This little actuator was printed in one process and consists of just 3 parts; An actuator, a printed gear and a servo Motor. The working principle is also quite simple, flexible fingers are connected to a slider with bridged "cables," which is then driven by a servo using a rack and pinion. What's not so easy is the print itself, there are very few printers out there which can combine flexible materials. My first experiments started with a E3D Kraken hotend and failed because the inactive nozzle permanently dragged across the print. The second experiments where before I installed a wipe system in the Blackbox but the third experiment finally succeed.
So how to combine flexible and rigid Materials?
Printing two materials next to each other create a fragile bond, especially when it's such different materials like TPU and PLA. My solution to making a strong connection between the two materials are undercuts. By hooking the materials together, the links can withstand high forces. I've tested several hooks, but I haven't been able to compare them yet.
This is just a proof of concept and a straightforward mechanism. There are so many things to test, but my goal is to print highly complex actuators with multiple motors and axis, but for now, I'm keeping it simple. Another thing I want to test soon is nylon cable bundles for high torque applications. I'm open to any input and will probably create a Hackaday project out of this once the Hackaday prize 2019 is over!