Open Source Rotational Engraving Adapter (Part 1)
This is the new buildlog.net open source rotational adapter for laser engraving. This allows you to engrave on a round surface. This design uses a friction drive method to rotate the workpiece. This has the advantage of keeping a consistent surface resolution regardless of diameter. This was designed to be 1000 steps/inch resolution. The length was sized to fit the 2.x laser, but you could easily scale it up to much longer or shorter. One design goal was absolute minimum height. This allows Z challenged engravers to be able to do some rotational engraving
The main feature of the design is the the two drive wheels. These serve several functions. They hold the rubber o-rings used to provide traction on the work piece. They have built in MXL drive pulleys and they have a spacer to ride directly on the bearings. These were 3D printed at Ponoko. With 3D printing, complexity is free. This encourages you to make the part do as many jobs as possible. I was initially concerned about the strength of these, but they turned out to be quite strong. I can probably reduce the material to take some cost out. I used the basic, cheapest, white flexible material. I was impressed with the detail level the material was able to hold. The belt fit perfectly.
At the other end of the assembly are the idler wheels. These also are Ponoko 3D printed items. They have bearings that press on each side. This allows them to roll freely with virtually no wobble. One idler has a flange on it. This acts as an end stop to the workpiece. It prevents it from “walking” while it is spinning. The stepper motor pulley serves the same function on the other end. This end is highly adjustable. There are three positions the wheels can be placed in. The plate can slide on the extrusions and you can flip it over. While all the adjustments are manual, they only take a few seconds to do.
Below is a video of some testing I did. I was trying to test a variety of shapes to see how they performed. In actual use the speed is very slow, because the the laser is primarily rastering along the length of the workpiece and this adapter just advances it a faction of millimeter at a time.
They all performed quite well. The only item that did not test well was a roll of duct tape (not shown). It was not very round so it wobbled a bit. It also has a sticky edge so it did not ride against the stops real well. The screwdriver at the end is an interesting example. While it did spin smoothly, it shows that if the image is not going to be at the same diameter as the drive area, some image scaling will be required before engraving. The bit is only 1/8″ diameter!
The design will be open source. There are a few tweaks to make before I release the drawings and 3D files. I may sell a complete kit for this. I estimate it will cost less than $100 with motor and extrusions included. I have not tested it in my laser yet. I don’t have the time right now, so I am going to have another 2.x laser owner do that for me….stay tuned for part 2.
Items Shown in video
- Drumstick
- Beer Bottle
- Odd Shaped Oil Can (remove oil before lasering)
- Wine Glass
- Tiny Screwdriver
Wow Bart, that rotary axis looks awesome
IS that 80/20 modular framing ?
It is Misumi frame 20x20mm. I find the Misumi is considerably cheaper the 80/20.
Is that no vibration when rotating and engraving?
I’m very impressed with the quality of the drive wheels, but what material/ process was used? I can’t quite tell by looking at the finish.
Hello I am wondering if the rotational unit kits are ready for sale, or if not are you selling the plans along with BOM. Please let me know I need two of them.
Thank you
Jade Elisar
The design is open source. The plans and BOM are free. I added links to the documentation at the end of the post.
If you’re not going to do the kit, can I get your 3d files and have them made at Ponoko? I really like your design, but alas I’m a writer with minimal precision skills. And I would pay over a hundred for that kit…I think most of us would. You need to get something out of this.
All of the source files are on the Wiki
http://www.buildlog.net/wiki/doku.php?id=rotational
Hi, could you tell me if you made these for sale complete
Many thanks
Brian
Sorry, I do not have plans to sell these any more.
Hi again, I am going to try and replicate this as I realy like it, I have managed to order most part, but not the drive wheel and idler wheel as you had these made, do you think you could let me know how many teeth on these wheels.
Thanks
Brian
Those parts are available at Shapeways.
Thank you very much
Nice blog. Thanks for sharing . Its useful information regarding Rotational Engraving adapters.
I am finding the links to be broken. I would like to get the files and build my own.
Thank you.
I added a link to the the 3D CAD File.