Preassembled Spherical Geneva Drive

by prtevol Jan 20, 2014
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Awesome model! I had to scale it up quite a bit but it printed well. You can see a timelapse video of the print here: https://www.instagram.com/p/BsEOeGKHZkN/

Seems to be scaled to 1/2540th... must have saved in some odd inches format

there are couple of fully printable index counters on TI , it would be nice to incorporate this thing into them as flat geneva wheels are generating too much friction to be useable.

Thanks mgg942, Its nice to see feedback. I updated a few things to help others with similar build issue in the crank clearance zone, a new file called GDprtevol2 has double the clearance, .559mm in the dig out area you mentioned. I also posted my layer size and speeds in the instructions (std medium qty for makerware abs on rep2x), similar to what you used, and added side dimensions snap shot for those that want to check the scale. Oh, somehow in my thing info edits I lost credit to where I found this spherical drive, its
derived from Mechanisms and Mechanical Devices 5th ed. page 195 there is no mention of if it was used in application. Yes the movement of this is jerky, its interesting to see more refined mechanisms that predate servo motion controls.

Now I'm a little disappointed - I'd thought that you'd dreamt up the design from scratch!
I'm sure that the changes that you've made will help others. I'm going to enjoy showing this to my engineer pals. Have to admit that it leaves the lay public a little cold - they don't have the right background I guess.

its a great thought....

What an elegant design! Do they exist in the 'real' world? Came across flat plate genevas in my professional life but nothing like this. Of course most mechanical indexers were scroll cam boxes with better acceleration and deceleration characteristics.
I've made one in Diamond Age PLA on an Ultimaker 1. Sliced with Cura 14.01. Scaled up 30 times !! to give a x dim of approx 105 mm. Support from the baseplate and brim.
I had two failures, both to do with the supported parts, so I changed from my default settings of 01mm layer height, 200C 100mm/s print speed to 0.2 layer height, 220C and 50mm/s. No problem.
Once off the print table I found that the 'bowl' was free to rotate but couldn't turn the handle. This was due to adhesion between the handle arm and the actuator arm to the support bracket. Once I'd freed these (about 20 mins with a knife) the actuator turned freely so the shaft had no or very little adhesion.

How should this be scaled when brought into Makerware?

Rescale object, it will auto scale (lower main body about 50mm long) move to platform. I also rotated it 45 degs so the length of the object is on the x axis.