I’m trying to cut some vinyl upholstery on the Lowrider. The laser cutter has this annoying habit of releasing chlorine gas so I’m thinking about a drag knife but I’m not sure the vinyl sticker one from Ryan’s shop is going to work. I also need some way to keep the material flat. Maybe stretch it over a frame?
Any suggestions?
There are some thingiverse mounts for a box cutter type blade that might work. Not sure how those will work turning sharp corners …
I saw those, I will try printing one tonight. The main problem is the hold down. Maybe a vacuum table? I would love to go the tangential knife route but I don’t have any more drivers for another stepper on my mini rambo.
Thanks
Yea i would think a vacuum table would work - i’ve seen one built for cutting foam board for model airplanes.
Just an idea – take a look at the needle cutter used to cut foam boards for model airplanes. Depending on the thickness of the vinyl it might be able to perforate the material enough to tear out the shape.
Pure conjecture since I’ve only read about this “trick,” but consider using contact/shelf paper. It works just like the painter’s tape “trick.” You apply the contact paper to both the spoil board and the back side of the material then glue them together. I think the blurb I read said they used Super 77 as the glue.
I was going to suggest trying one of the sticky mats they use for Cricut or Brother machines, but I don’t think they come a yard long. You can get just the sticky glue from online suppliers and make your own.
Maybe repositionable spray adhesive ( 3M Repositionable 75) onto a foam core backer?
I was just coming to say this. There are also temporary spray adhesives. You could just try that, directly onto the back of the vinyl, and your spoil board.
I have cut some vinyl on my mpcnc. Ryan’s drag knife and instructions should work. I would tape the vinyl perimeter down to a flat rigid surface.
I think the Roland style vinyl cutter(similar to what Ryan is selling) with a 60deg blade should work. I have just added one onto my MPCNC and still have a bit of fine tuning to do, but it seems to work well for vinyl.
The test cuts in the background on the previous photo I posted was done with a Stanley blade type…and I had huge struggles to get it to work. I wouldn’t recommend you go that route.
@d30n - where did you find that holder? Does it just slip over the Z conduit rail? That’s slick!
Upholstery vinyl is much thicker than the sticker vinyl you appear to be showing. I’m not saying the roland-style cutter wouldn’t cut it, but I don’t know if just taping the edges would hold position well enough to fight the stretch inherent to the fabric over the length in @droesch’s original photo.
Well after a few hours of noodling with it, my conclusion is that I really need a tangential drag roller set up with a steel cutting wheel.
The experiment thus far has included slapping together a quick vacuum table. Covering it with a light coat of spray adhesive and using my 11° v bit. The really tricky part about the hold down strategy is there are lots of v cuts where the upholstery is eventually folded together and stitched. As soon as you cut through the cloth, it bunches up.
The commercial systems that I see online have a large perforated rubber belt that acts as a huge vacuum table. The cutting head is also connected to a stepper motor which is similar to the tangential cutter project that someone was kind enough to link above.
I’m not for sure if the mini Rambo extruder connection could run the tangential stepper but I’m guessing not since it doesn’t seem like people use that port for fourth axis.
Here are a couple links to more commercial systems.
I had to design my own holder using Fusion360, as I didn’t want to remove my router. The blade sits 12mm (just short of 1/2 inch) below the collet if there is no end-mill in it. It slips onto the one conduit of the Z rail but it’s quite a tight fit (initially I wanted to drill and tap into the Z pipe to secure it with a screw, but that turned out not to be necessary) I agree that holding down your material will surely be the biggest challenge.
Thoughts (in no particular order)
Tom,
So, I marked this as the temporary solution because the cricket maker can cut pieces that are up to 24 in long so it will work for this project. Thanks for the idea!
The long-term plan is to still try to get a tangential stepper roller cutter working on the lowrider so that I can cut bigger pieces. Inkscape has some plugins that seem to generate the gcode but I haven’t dug into it yet.
My first upgrade will probably be changing out my mini Rambo with a board that has an extra driver to control the rotary cutter direction. That would also open the door to some fourth axis messing about 
I have seen a lot of talk with the Primo on what boards do what but I have not really paid attention.
What would be the best board supported by Ryan to upgrade my lowrider to? I currently run my mini Rambo headless with the LCD screen.
Thanks so much for everyone’s time and thoughtfulness in helping me work through this!
I’m using a CNC Shield on my MPCNC since i got two by accident when I replaced the controller in my K40 laser. It’s limited to 3 axes so won’t work for your project.
Either RAMPS or RAMBO should meet your technical needs. Ramps are less expensive but quality is hard to ensure and they are more susceptible to damage to the drivers or underlying arduino if things get shorted. Rambo is more $ up front but better protected, used heavily by users on the forums, and firmware is actively supported by Ryan.
32-bit boards are available, but I dont know that the extra power is needed for these machines.
If I were buying today, I think I’d get the full RAMBO board.
Well Bob’s your uncle, I got my machine cutting vinyl upholstery! Taking Tom’s suggestion, I took a look at an old silhouette cutter. I ended up swiping the drag knife from it and with a little bit of 3D printing bailing wire made myself a makeshift spring loaded mount.
I covered a board with a layer of repositioning adhesive and made myself the world’s biggest Cricut!
I still hope to make a purpose driven machine someday with a tangential head but this will work for now. Thanks everyone!
Okay a little update. I ordered a more robust drag knife with a nice aluminum housing. I reworked the mount so that it can be height adjustable as it borrows the thread geometry from the DeWalt 611 router (Thanks GrabCad!).
I haven’t used it to cut yet but I’m excited on how much more rigid this version is!
