LR2 for cardboard processing

Thought I would share the build here, maybe it will be of interest to others. Also, I am still reading posts here, so sure I have missed many great pearls of wisdom from the members here, please feel free to point me in the right direction!

Been wanting to build a CNC that could score and cut double wall cardboard. We need to make custom boxes a lot at my office and it is a real knee killer and a time consuming process. You know, crawling around on all fours measuring and cutting.We start with a 4’x8’ double wall pad of cardboard, these are large boxes. This is the type of work that screams for automation!

I originally thought something like a Maslow might work, but upon further research I knew that wasn’t going to work well. Then I eventually ran across the Low Rider, and I even found some info of people using drag knives with it.

First off, Ryan has done a great job on the STL files. Wow, they printed out great. We have a couple of Prusa Minis at the office and they knocked it out just fine. Not a single issue with the printing. I even left them in fine mode and with a high infill since I was not in a hurry. Here are the first parts I printed.

After a day of printing I ordered up the parts from Ryan. Went with the SKR option as that is what was available and should work well. Dang, those shipped out fast and arrived today. So thought I would print up some cases for the screen and SKR. I ended up using this for the screen:


A well done case that seems to work very well. I turned on supports only for the ball mount.

Fits very nicely.


SKR case is currently printing. I’m using these STL files:

Next up to print will probably be a drag knife. I think this will be the first one I try:

If the simple drag knife does not work, I might have to give this one a try:



I imagine there is a thread here in the forum for this project?

Hope to be able to get to work on the actual build next week. Right now it is easy to send some parts to print, but the building will take some real time, and that is rare right now.

The table will be a pretty simple affair, and probably on wheels. It will double as a nice big table when not in use. That is one of the attractive features of the LR2, it does not have big rails and stuff ruining the use as a table. Since I do not need very tight tolerances for the cardboard, I’m not going to go crazy on the table. With this said, I think I will set this up for a router as I may use it after hours and on weekends for making wood chips.

I’d also like to build it with the idea of using a vacuum to hold the cardboard in place. Will need to do some testing on this as I’m not sure how well this works with cardboard, but think it will be fine. I’m planning to draw a vacuum through the surfaced MDF on the top of the table. No drilled holes.

No plans for a laser as I do not want the liability of that in our shop. The goal will be for a rather simple to use machine that my team can put to good use in a safe manor.

Thoughts? Suggestions?

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Oh yeah, one more thing. Probably sneak off to the metal shop for some SS tubes. Kind of shocked by the prices out there. If I can get some locally for about the $50 mark, I might grab some extras I could ship out to folks that are planning to build. Let me know if you are interested. We ship a fair amount here, so hopefully the covid rates are too silly for a 5’ box.

It the amazing cardboard cat house maker!
Or my grandkids will have the best cardboard rocket ship ever LOL
I had not thought about using the LR2 for a custom box maker. Great idea!

I keep being amazed by the new uses people come up with for these machines. Sometimes we forget that these are not CNC routers, they are 3-axis robotic manipulators with routers as their tooling.

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Did the skr pr v1.2 fit into the case you printed that’s stated for a 1.1?

I have not fully test fit the SKR yet, but it seemed to fit in the bottom of the case. I have not printed the top just yet. Wanted to make sure it looked like a good fit first. I had the same concern. I guess the big question will be if any of the ports moved around.

Didn’t make it to the metal shop, but did spend a little time bolting all of the bearings and motors in. So, basically all of the easy bits are done. Now onto the wood and may be do some wiring to see if I can get the motors driving while the wood project progresses.

Thanks. I had a chance to look up the manuals and all the dims and port locations look the same. In printing now. :+1:

Finished printing the cover and snapped some quick picks. Yep, all looks good. My printer weirded out a bit on the corners… Otherwise very nice.

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And a boring photo of a bunch of bolts… Wood parts are next.

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I have a simple drag knife option for you. I did a remix of these 2 together as I am already using the tool holder for my laser.



I have printed the attached stl’s and they seem to be good, but I haven’t tested it yet. DragKnife.zip (158.1 KB)
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Have you figured out your CAM solution yet for creating your drag knife tool path lead-ins to align the simple drag knife?

Cool, I’ll give that a try. Not played with the paths yet. Need to get the basics done first.

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For those finding this in the future: https://www.thingiverse.com/thing:4697691

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Sorry it has been a while but we finally got back to work on this project.


We have it up and running doing the basics and learning as we go. Seems like we may have a low voltage issue so will be doing a little research on that next. Basically the machine is pretty slow, but seems to be doing well with some pen tests.

Waiting on a few parts to clean things up, but coming along nicely.

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Guess we have to show this one…

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Interesting project to follow.
For some product I make I also need custom cardboard boxes. But it´s rather expensive to order all the custom sizes, so I was also thinking in trying this in due time.

Do you plan on cutting the cardboard completely through, or just the fold lines? For the fold line I imagine it could be difficult to do this with a knife as the box looses structural strength, no?

Some rough testing with Drag Knife number 2, it does not like the tough double wall cardboard we would like to cut. But it will cut through the thinner ECT single wall pretty easily. More trial and error to test.

The double wall attempts loose steps.

For creasing you swap out the knife to a different tool.

Quick update - We have managed to cut many circles from single wall, and now double wall. The double wall takes about 4 passes to cut all the way through. Currently using a #11 Xacto blade, but sure this all will change with more testing. Moving onto a square shape as I suspect it will cut a little better than a circle, and we really only need straight cuts for our boxes.

Starting to look very promising. :slight_smile:

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They make a creasing tool for fold lines. Basically just a thin caster style wheel. The big cnc cutters can control the angle the blade/wheel sits with the gcode, but a caster style wheel should work, or at least be close enough.

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Out of curiosity, could you not just use an endmill and a router for the through cuts?