Build Log 3: Upgraded Fingers and Rotation Wrist.

A project log for Protoype Heavy Duty Robotic Arm Mk.1

A remarkably strong and sturdy 3d printed robot arm. With rotating wrist and articulated thumb.

Gray EldritchGray Eldritch 07/20/2017 at 06:200 Comments

After last week's filament disaster, I wound up using the same hand design from MK. 1, none of the faulty plastic was used for that part, and I was overall pretty happy with it! Especially the articulating thumb. The one problem I was having however, was the fingers would jam from time to time, being made of rigid plastic. So I fixed that by replacing the five plastic fingers, with 4 flexible-jointed fingers. This is also part of how I plan to make this design modular, more on that to follow. But all four fingers are easily, individually removable and replaceable. I had some leftover flexible filament lying around from a sample I was given at CES this year, so I managed to get my FLSUN delta printer to print out just enough joints to make the new hand. Flexible filaments are such a pain in some of the cheaper printers!

The dark blue material is printed in Algix filament. I love this material! It's make of algae and is non-toxic, and they have some awesome colors. Unfortunately, I'm working on an artist and college student budget, so I can only get it for special projects like this one. It is a bit coarser than some other filaments, this caused some problems when fitting the rubber joints, when they slid right into and ABS finger, But after a little tinkering, I managed to get them all to fit.

The rotation wrist has been upgraded with a second slave servo, I found just one had enough power to move the hand, but really struggled when the hand was holding something. I plan to eventually make a more elegant solution to this, but for now, this does the job very well! The central gear also has a steel bolt running through the wrist, into the hand. Eliminating the previous arm's biggest weak point and making it remarkably stable for a 3d printed part!