Open Source Rotary Attachment

[bdring]

I want to get started on an open source rotary attachment. I thought one could easily be designed for well under $100. I was hoping to start an information gathering thread here before starting the design.

My first thought is to have the workpiece ride on rollers. If the perimeter of the rollers translates back to 1000steps/inch at the motors. You would simply use the rotary as the Y axis. The X would scan normally and the rotary would be the Y.

The other end would need to be adjustable so it could handle a different diameter, like a wine bottle or wine glass. If there was a lot of Z change across the X scan, focusing would be a problem, but it would require a serious controller to handle that and most Z's won't be able to handle the speed. Maybe a long focal length would help.

[trwalters001]

Here's what I'm intending to build:

It looks like the left side (with the height adjust knob) is a scissors-type lifting arrangement.

I don't think this would be hard to build at all.

[bdring]

Yes,

That is what I had in mind. What do you think would be good design criteria for the work piece size?

[trwalters001]

The "height adjustment" end of the fixture slides along the rail (I think.)

It seems that we'd need some way to adjust the spacing between the wheels too.

I've seen some stuff here: http://www.epiloglaser.com/sc_drumsticks.htm

and here: http://www.epiloglaser.com/sc_beermug.htm

that shows the size range we're probably talking about (wine glasses or champagne bottles might be larger.)

Take a look through here: http://www.epiloglaser.com/sample_club.htm

Lots of good ideas and vector files.

[araknid01]

Do you think that while you're designing this, do you think it could be made for both lasers? Those with the original lasers would like one also. Do you think that we could make a separate stepper motor control it instead of using the XY or Z?

[lasersafe1]

Here is the way the do it in the ULS-25. The item gets pinched between the two rollers. When I plug this item in, it plugs into a connection that is in parallel with the normal Y axis. I have a DPDT switch that can swap 2 of the 4 stepper (A+, B+) motor wires between the two connections. It doesn't matter if the other Y axis motor is still hanging out there on two wires since they no longer have a completed circuit through the motor.

I have only used this once to test it. I engraved an apple. Items like an apple would be difficult to engrave on the platform you have shown in your first post. Sometimes when I stop by the dollar store, I often think of purchasing some of their cheap glassware to engrave, but I don't have much free time for it.

[twehr]

Rotary attachments tend to take up quite a bit of space, especially vertically. I am curious, what is the total z height that will be available in the new smaller laser design. With the attachment installed, what is the max diameter item that could be engraved?

tim

[bdring]

The ULS model requires special software or image stretching to work. I know FSE does not support that. Does the Lightobject DSP directly support it?

With that said, a little image manipulation might not be that bad. Most users on this site are probably up to that. I know I could write an app with a simple interface in less than an hour.

I think I will investigate both methods to see what has the best combination of cost and ease of use.

My new laser only has about 4" of vertical travel. I am sure the rotary attachment could fit, but the actual size of the workpiece will be severely limited.

[trwalters001]

Bart wrote: "The ULS model requires special software or image stretching to work."

Why is that? It seems to me that it would work the same as the other type if they're both at 1000 steps/inch...

Tim

[bdring]

Things with a different diameter will engrave differently unless the software knows about it. Surface length per degree depends on diameter.

The other style does not care about diameter because it uses the surface of the item to drive the motion.