Tuesday, July 16, 2013

Prosthetic finger first print

My first attempt at printing the prosthetic finger

Here are some pictures and printing data about the prosthetic finger from Gael. One of the areas of 3d printing that has been a struggle is printing of small parts and these models really push what I have learned to do so far. The following are photos of the parts with comments about what settings I used. The camera I used, except for the last picture, is a small point and shoot and does not focus as close as I needed. For the last picture I dug out my Canon SLR. I will do some better pictures of the other parts later on.

Actuators. Printed at 20mm speed, .2 mm layer height, .3 first layer and solid infill.

Servo holder. Printed at 40mm speed, .3 mm layer height, .3 first layer and solid infill.

Finger. Printed at 20mm speed, .3 layer height, .3 first layer and solid infill.

Worm halves. Printed at 20mm speed, .2 layer height, .3 first layer and solid infill.

A little bit of explanation goes along with this picture. For the moment I have given up on printing things like worm gears in the vertical orientation due to problems with overhangs and support. I have not yet been able to print these without having to do an excessive about of carving and sanding. My current experiments in this area are to cut the piece in half vertically and then rotate each half to be flat. Each piece is then printed and the pieces glued back together. In the following picture the red line down the side of the gear can be seen. I used some goop made from acetone and red filament as glue. 

Worm. The glued together worm gear.

I will be starting to assemble the finger later today but I don't yet have the servos in hand. The size of the worm gear makes me wonder about how to attach it to a servo. I suspect I will have to go in search of some very tiny screws.


  1. Hi thanks for posting the pics. The holes on the wormgear won't match the actuator servo wheel I think, because I designed this without the servo itself in my hand. I used specs from the Hobby site and from my experience, it isn't always correct. What matters to me for now is if the principle works. If the actuators actually do their job at closing the finger when the big gear is rotating.
    Hope you understand how to mount it together!!

    1. I'll give it a try. I don't have the Corona servos yet but I do have a micro size servo from another project. I'll make something that will match up between the servo and worm gear. I should be able to assemble and test tomorrow.