A different kind of rotary attachment

[Douglas J Miller]

Hello everyone! I'm a long time lurker here, and infrequent poster.

I have come up with a different kind of rotary attachment, and I'm wondering what everyone thinks of it. I've posted a video on youtube of it working. You can view it here: http://youtu.be/ksnVMXjrR1s

It's made for my Full Spectrum Engineering 40watt hobby laser (a machine I love!), but it can be adapted to a lot of other lasers.

So, let me have it! Good? Bad? Don't care? Don't be too mean to me, my wife hates to see a grown man cry. :) Lol

Douglas

[Joe Hillmann]

Pretty slick. I saw a picture of one that kind of worked like that but much more complicated that someone had built for engraving on pumpkins

http://www.youtube.com/watch?v=SDqTp33xjME here is a video of it.

[Dan Simone]

Wow, that is really cool. I always think the simpler the solution the better.

[Gary Hair]

Two things - if it's attached to the X-axis rail how you do you focus? Also, doesn't the way it's attached limit the size of what you can engrave? Maybe I'm not seeing it right?

Gary

[Douglas J Miller]

Gary, The attachment rises and falls with the table. You focus it with the table height just like normal. And there are limits to what it will handle, but if you don't need to do large diameter items it works great. For the person who just wants to engrave a few pens now and again, and similar tasks, it's ideal. Of course, that's just my opinion. :D

[Chris S Martin]

Mr. Miller I would love to know how to build one. I have a 60w Full Spectrum Laser which I also love. Thanks for anything that you could share.

[Gary Hair]

I just looked at it a bit closer - at first glance it looked to be firmly attached to the x rail, I didn't realize it actually floats on the rail allowing you to set focus. It is a very clever design.

Gary

[Ernie Balch]

That certainly is an interesting design, You have me wondering how to adapt that to my shopbot router as well as my rabbit laser. Thanks for sharing.

ernie

[Mike Null]

Doug

thanks for posting what appears to be a great idea. I assume it would be ok for interested parties to pm you for more details.

My questions deal with increasing the working diameter and length as well as whether this can be adapted for use on any machine.

[Douglas J Miller]

Dan, i agree that often the simpler the solution the better. Sometimes a lack of money can lead you in all new directions. :)

Mike, The design can be adapted for almost any gantry type system. The size of object it can take is a function of table size and depth. If your table is big enough there is no reason one couldn't be built to handle wine bottles or something like that. While I have my doubts that a truly 'universal' one would work very well, I'm going to start collecting data on other machines, and see just how many different sizes it would take to make everyone happy.

Anyone who wants more information, please PM me. I like this forum too much to take a chance of breaking the rules and getting kicked off. Lol

[Keith Outten]

Doug,

Its pretty clear to me what your intention is here so I wouldn't worry so much about losing your place on the roster :)

Honestly I think your approach is innovative and interesting so I hope that lots of people here will provide you data that you can use to make improvements.:D
.
.

[Dee Gallo]

Doug, for those who want to help you by providing info on their lasers, could you list the kind of info you need? Your invention is a definite improvement over the present rotary I have, that's for sure!

cheers, dee

[Douglas J Miller]

I can do that, Dee!

Here's the list, for anyone who cares to help out. Wouldn't it be nice to come up with a 'universal' one? Well, there I go dreaming again.... But I guess I can try! :)

Measurements needed:

1: Total table travel up and down.


2: Table X and Y dimensions.


3: Gantry height and width. This is the gantry itself, not including the firing head or any of that.


4: Distance from front face of gantry to beam. Easiest way to get this is to place a piece of scrap in the machine, in focus. Then hold something square up to the gantry and make a mark on the scrap directly below the front face. Fire the beam, and measure between the two marks.


5: A guess as to the amount of room between the top of the gantry and the lid. For sloping lids give the best guess at the front and the back, counting only that above where the gantry can actually travel through.


6: Focal length of lens.


7: Make and model of laser.

I think that should do it.

PM me with all of that, and I'll make a chart and see what we have.

And Thank You All for your interest. It's a bit overwhelming, but in a good way. :)

Douglas

[Mark Ross]

We have a 3D printer at work, so if any gears / brackets/ fittings etc. need to be fabricated let me know! We have an Epilog 36EXT and I would like to make a system for our unit.

[Joe Hillmann]

How does you laser zero itself out? I ask because the way you have it set up on your machine would require changing the home position on a universal laser or for the right side to be pushed up against the y rail to allow the head to hit the stop button when it re-homes itself after every job.

[Douglas J Miller]

On the laser in the video 'home' is where ever you set it. I just move the head to where I want to start, and after the job is done it returns to that same spot. The machine does have a switch at the top left position (0,0), but that's not set in stone. I move the head where I want it, and that's the new 'home'.

[Joe Hillmann]

On the laser in the video 'home' is where ever you set it. I just move the head to where I want to start, and after the job is done it returns to that same spot. The machine does have a switch at the top left position (0,0), but that's not set in stone. I move the head where I want it, and that's the new 'home'.


What about when you first turn it on? Does it then zero itself out at a calibrated home position? Not that it really matters I am just curious.

[Douglas J Miller]

When you first turn it on where ever the head is is Home. I can reset that by moving the head to the top left and it'll call that Home. It does not automatically seek out any one position to call Home.

[Joe Hillmann]

So does that mean everything you do is based off of measuring from the red dot rather than using rulers mounted as solid stops?

[Douglas J Miller]

Mostly. I go by the red dot for most things, but I can set it back left and then move off from that a given amount. Jigs I've made I have a known distance from the back left, so I start there and know I'm always right on. Most other stuff I do by the red dot.

[Bill Cunningham]

Hmmm; I have a couple of old soft rubber rollers with bearings on the ends that I salvaged from a scrap photo copier a few years ago.. They have just been taking up space on a shop rack.. This is giving me an idea of what to use them for. I just have to find some time to experiment.
This is truly the KISS version of a rotator a lot of folks have been looking for..Thanks for the great 'outside the box' idea Douglas!

[Dee Gallo]

Measurements for Epilog Mini 35w
1. table travel with table in place: 4 1/4", without table and grid, 6 1/4"
2. 18" x 12"
3. gantry 2 1/2" x 21"
4. ?
5. top of gantry to lid 7/8"
6. focal length 2"

[Steve Busey]

Was doing a general search for "jigs" when I found this timely mention... :)


for engraving on pumpkins

http://www.youtube.com/watch?v=SDqTp33xjME here is a video of it.

[Mayo Pardo]

Anyone know whatever happened to this idea? It appears that the website and email given in the Youtube videos is no longer active.

[Bill George]

How does you laser zero itself out? I ask because the way you have it set up on your machine would require changing the home position on a universal laser or for the right side to be pushed up against the y rail to allow the head to hit the stop button when it re-homes itself after every job.

That was my first thought. When first turned on, a Reset or Home and mine goes to upper Right corner. So why can't it just set on the Honeycomb table and then be pushed forward and back.

Second thought, those X & Y stepper motors are rated at so much torque, add some additional load as pushing a wheel or whatever you want to call it around the table, the motor misses some steps and its bad news.

[Jim Galer]

Hi Everyone,

First time poster, long time lurker. I was inspired by this thread to build my own rotary attachment for our Trotec. It was fairly easy, and it works quite well. I cut all the pieces out of Delrin for the pantographs on either side, and used conveyor rollers with urethane covers. The nice thing about this design is that it doesn't matter what diameter the object is, the laser doesn't care as long as you focus as the start. Some of the concern areas are that when getting into the larger diameters, there is more slop in the pantographs and they have more play in them than I would like. This is a minor concern, but the cantilever effect does put more stress on the gantry than I'd like.

Anyhow, take a look and feel free to copy, suggest, make improvements, or whatever.

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[Mayo Pardo]

Jim that looks like a really nice design! Some questions:

Is the front roller with the two black sleeves on it just for additional stability?
Does the depth of the pantograph require it to be that size from front to back?

Have you determined what the minimum and maximum diameters are that you can engrave?
Maximum length?
Do you have to install the device after the Trotec homing procedure is done?

I haven't used Delrin - do you think aluminum or MDF would work for the frame?

I'd really be interested in either a bill of materials/parts list, or possibly even getting a parts kit from you if you decide to produce one.

[Gary Hair]

I think it's pretty clever but you are very limited in the diameter you can engrave. If you divide your Y axis size by Pi you'll get the max diameter, right? Then you have to consider whether it can go the full length of the Y axis due to the design. You mentioned this, but I don't think I'd want to put that much strain on the gantry - motors, belts and bearings will surely wear with the extra effort needed to move it. If you used it very seldom for small diameter, lightweight parts then it wouldn't be too bad, but otherwise it would be worth spending a bit on a more "traditional" device - or making one...

[Jim Galer]

Hi Mayo,

The front roller was added for additional stability
The depth of the pantograph definitely drove the size from front to back. I added two x's to keep the depth to a minimum while maximizing the height.
I didn't determine the diameters, although it probably wouldn't be difficult. In one of the pictures, there is a note on the fixture that you can't do more than 11" of circumference due to the travel of the fixture during engraving. It will run into the back wall of the engraver or the front wall. With a little more thought on width of the fixture and maybe another layer of x's, this could be increased.
Maximum length is set somewhere around 20" (the width of the rollers).
I set the laser in the software to NOT go to 0,0 after cutting. It homes when I start it up, then I drive the lens to the middle of the y axis and about 1" out from the x axis. When the job is done, it returns here without crashing.

I think aluminum or MDF would work well, probably aluminum better. I just wanted something I could cut out quickly and I had a lot of delrin sheet.

I never really made a parts list or BOM. The design just sort of evolved as I ran across issues. I got the conveyor rollers from McMaster Carr. I'd like to have smaller rollers with urethane covers, but these were available and cheap.
I think even a steel drill rod with a urethane cover would work fine as long as it could rotate easily.

I might have the Corel file around with the pantograph end pieces if you're interested. The rest of the fixture are just shoulder bolts, nylock nuts, washers, and a couple of clevis pins.

[Jim Galer]

If you divide the y-axis by Pi you should get the maximum theoretical diameter minus the fixture width. As far as gantry strain, I agree to some extent, however, the gantry doesn't move very fast or very much due to the 'raster' scanning of engraving. It mostly creeps along which is pretty easy to move with the rollers. I'm more concerned with inadvertent gantry/fixture crashes and the strain that would put on it. It certainly could use some improvement, but it has some potential.

[Gary Hair]

If you divide the y-axis by Pi you should get the maximum theoretical diameter minus the fixture width.
I just realized that would give you the maximum engravable length but the diameter would only matter if you were trying to engrave around the entire circumference.

As far as gantry strain, I agree to some extent, however, the gantry doesn't move very fast or very much due to the 'raster' scanning of engraving. It mostly creeps along which is pretty easy to move with the rollers.
Very true


It certainly could use some improvement, but it has some potential.
I think it has lots of potential! I think optimizing/minimizing and using aluminum would go a long ways to improve it, but it certainly is a great start.

[Dave Sheldrake]

I love this kind of thing Doug, while I have rotarys they don't get used much but the focussed mind that creates something like you have is inspiring to say the least.

Anybody looking to do the same on a chinese machine, you can reset the home position to the top middle easily in the software so the head won't clash when it goes home.

[Mayo Pardo]

Jim I sent you a PM

Dave:
While Doug started this thread in 2012, Jim has just recently put his own spin on a similar device.

[Mayo Pardo]

Jim

If the material of choice was more rigid, (like aluminum) do you think you would be able to eliminate the front most roller? If so, this would allow engraving a larger diameter because you would have more available travel in the Y axis. If I calculated right, the circumference of 11 inches will allow up to 3 1/2 inches diameter.

Would you be able to share the Corel file or is it available for purchase some place? I'm interested - it would at least give me a starting point for making a similar one for my machine.