CNC Machine Rolls Up An Axis To Machine PVC Pipe

Whether it’s wood, metal, plastic, or otherwise, when it comes to obtaining materials for your builds, you have two choices: buy new stock, or scrounge what you can. Fresh virgin materials are often easier to work with, but it’s satisfying to get useful stock from unexpected sources.

This CNC router for PVC pipe is a great example of harvesting materials from an unusual source. [Christophe Machet] undertook his “Pipeline Project” specifically to explore what can be made from large-diameter PVC pipe, of the type commonly used for sewers and other drains. It’s basically a standard – albeit large-format – three-axis CNC router with one axis wrapped into a cylinder. The pipe is slipped around a sacrificial mandrel and loaded into the machine, where it rotates under what looks like a piece of truss from an antenna tower. The spindle seems a bit small, but it obviously gets the job done; luckily the truss has the strength and stiffness to carry a much bigger spindle if that becomes necessary in the future.

The video below shows the machine carving up parts for some lovely chairs. [Christophe] tells us that some manual post-forming with a heat gun is required for features like the arms of the chairs, but we could see automating that step too. We like the look of the pieces that come off this machine, and how [Christophe] saw a way to adapt one axis for cylindrical work. He submitted this project for the 2019 Hackaday Prize; have you submitted your entry yet?

31 thoughts on “CNC Machine Rolls Up An Axis To Machine PVC Pipe

      1. And why at the moment the project is already finished?
        Although a very kind gesture if it happens once…
        but this is the third time and it starts to smell like an advertisement, which is not what are comments for.
        Comments are intended for people to comment the project, praise it, make fun of it or to burn it to the ground or make smart comments on how it also could have been done.
        What would the world look like if every CNC related build is rewarded with free boards?

      1. Looks like the cnc is using larger Nema23 motors. The smoothieboard only has 2amp stepper drivers which would limit the torque of the steppers. With the many cheap smoothie clone boards available, the sale of authentic boards probably have dwindled. Version 2 is late and will probably be fairly expensive. Too little to late when there are so many 32bit boards to choose from now.

        The developers wont even acknowledge the shortcomings of the firmware.

  1. Interesting, I’ve been considering a chunk of similar pipe as the body/frame of a delta 3D printer. One of the more interesting problems I’ve been chewing on is cutting it such that the ‘tower’ spacing is accurate.
    This guys solves that problem in the process of making chairs.

  2. That’s stage lighting bracing, not antenna tower. Tower sections have a different bracing pattern, to provide a level place for your foot when climbing. It’s painful to watch someone on TV climbing stage bracing that standing in for an antenna tower because the props people used what they had on hand.

    1. My first job out of school was climbing radio towers. Real (i.e., non-trivial) towers aren’t built to climb on the structural struts — they have ladders or pegs for that. Structural members aren’t intended to take bending loads like that (even though they have ample strength), and generally aren’t spaced for human-sized convenience anyway.

  3. Anyone know the dimensional accuracy of a lighting truss like that? I’m guessing they’re welded in a jig to prevent any heat distortion? They’re obviously very strong, I don’t think it would’ve occurred to me to use one like this.

    Sweet build, does it stink up the whole shop when its running?

  4. Nothing new we built a similar machine back in 1994 at JH engineering in Birmingham Al to cut contoured holes in rectangular tubing for the manufacture of cruise missile shipping pallets do don’t make a big deal out of this manhine.

      1. Everyone complains about things like the $1000 toilet seat but, while I am sure that some overcharging or money laundering is hidden in things that way, it doesn’t take into account that some of these supposedly gross misuse of funds are actually because the part or tool are not as mundane as the description sounds.

        For example, if I recall, that specific toilet seat that everyone likes to point at actually some custom molded part specifically for the lavatories on high altitude long range bombers or something so there was no economy of scale.

  5. needs a throwaway pipe of slightly smaller diameter for every pipe it repurposes?

    I was expecting some sort of finned metal rig sort of like a cylindrical plasma tab that could be expanded to fit many diameters of pipe. Just control your cnc rig so it knows that zero is the edge of that jig and never go “below the hard deck”

    1. It uses the long X shaped mandrel made of wood inside the pipe. It fits closely enough the pipe doesn’t wobble around and he has one end made so that driving wedges in locks the pipe to it.

      Looks like he can get a lot of use out of that before enough of the edges are cut down by the end mill where the mandrel would need repair or replacement.

  6. This is for sure a cool project however… that first chair they show – would it really hold up to a person sitting in it and leaning back even a little? This looks great but I don’t really see it being rigid enough to be used like a normal chair.

    1. There’s not too much of melting. You can see nice chips flying. You can increase feedrate to improve chipload if machine is rigid enough. Also this project might benefit from using better milling bit. I’ve found “half straight” chinese bits can do wonders for the price, however they are rather brittle. Another solution might be to do second pass with 90 degree v-bit to chamfer the edges slightly, which will also remove the burr.

  7. Interesting to see this done at this scale. I played around with this same concept back in 2012 with acrylic tubing and delrin rods on my Epilog laser using its rotary attachment. I figured if I could etch circular objects why couldn’t I cut through them. It actually works rather well for some very cool end results.

  8. PVC can’t/shouldn’t be re-processed, whether cut, laser, molded, etc. Me think that surgeon mask she is wearing is not going to do you any good… possibly trapping those highly toxic fumes between your nose and life.

    Hang on a minute… was that post a hoax or…?

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