Open Source Rotary Attachment

[bdring]

twehr asked me where I left off with the rotational engraving attachement. Here is a rendering of where I left off. The goal was to make an exact 1000dpi device with as low a profile as possible.

This uses two 3D printed drive wheels. Based on the Ponoko price, these should cost about $8 each. I think that works well because a pulley alone at that size is at least $6-7. This also has a groove built in for an o-ring that will produce 1000 dpi. The nice thing about 3D printing, is that complexity is free. The belt is not shown in the rendering so you can see the detail of the pulleys, but it is intended to be a double sided timing belt that goes around the bottom side of the motor pulley.

The other end uses simple, manual adjustments to move a set of idler wheels. One wheel has a stop on it to prevent the workpiece from "walking" while rotating. The end plate can raised or lowered a little and can be inverted. It also has several extra sets of holes for bigger objects. The max length will probably be a little longer.

I don't know how this will play with the 2.x. I have some ideas on how to get a little more head room for it though.

[twehr]

The DSP does know about varying diameters. I have not tried it yet (don't have the rotary attachment yet), but know that when you set up to do rotary work, you have to tell it the diameter of your work piece. So should not be an issue for the v2 DSP (v1.x does not natively do rotary work).

I was wrong. The DSP allows for separate calibration, but expects the kind of attachment where diameter is not an issue (like Bart is proposing). didn't want to leave anyone with the wrong idea.

[bdring]

I think there will always be times when a little image manipulation is required. If you have a wine glass, for example, it may change diameter from where it is mounted to where the engraving is and may even change diameter over the engrave area. AI little pinch or pull in the right areas would be easy to do in many image editing programs.

[thechoochman528]

hmmm, you could adapt something like this to be used as a laser lathe as well, but with a fast spinning motor and more robust chocking of the work.

[bdring]

That is an interesting idea and potentially a simpler problem to solve. Sounds like a fun experiment.

[bdring]

I'll bet you thought I forgot about this project.

I am still missing some parts like the belt and o-rings. These are all McMaster parts, so I should have it all done pretty soon. It is basically the same design I proposed a while ago. I added an extra o-ring right against the other one. I was afraid a thin section like the base of a wine glass would not stay on the o-ring. Now it will ride the groove between them. I was worried about the strength of the 3D printer wheels, but they turned out to be super strong. The built in MXL pulley is perfect. This drive system gives an exact 1000 dpi surface resolution.

[whmeade10]

Looking good Bart! I will definitely be building one of these. There is a wine maker in my family and this would be great for custom wine bottles and glasses. I take it this will plug into the Z axis. I will need to connect a plug to the Z controller so it will be easier to go between the two.

-Bill

[bdring]

It temporarily replaces the Y axis. Any controller even Mach3 should be able to use it. Some controllers may be able access a separate dedicated driver for it. I will probably integrate it into the 2.x so it is a quick install and gets the most useful height. I don't have a lot of time to play with it, so I might send it off to twehr for testing.

[bdring]

Here is the idler end. This piece is designed to slide on a piece of extrusion. You can also adjust the width of the idler wheels. Each wheel has two bearings to eliminate wobble. The flange on the one wheel keeps the engraved items from walking forward. The drive pulley on the other end, serves the same purpose. The long raised ovals slide in the extrusion slots to keep it smooth and parallel.

It is all manual as opposed to some of the screw jack style versions, but the whole thing including motor will probably cost less than $100.

[twehr]

It temporarily replaces the Y axis. Any controller even Mach3 should be able to use it. Some controllers may be able access a separate dedicated driver for it. I will probably integrate it into the 2.x so it is a quick install and gets the most useful height. I don't have a lot of time to play with it, so I might send it off to twehr for testing.

I'm ready. (of course, you mqy never get it back! )