Putting my plan together

New Home Forum Mostly Printed CNC – MPCNC Troubleshooting – MPCNC Putting my plan together

This topic contains 6 replies, has 3 voices, and was last updated by  Lou Spinuso 1 year, 3 months ago.

Viewing 7 posts - 1 through 7 (of 7 total)
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  • #13685

    Lou Spinuso
    Participant

    Hey all, so I’m really thinking of building one of these, probably after the summer, and I pretty much have everything I need as far as electronics go (5 steppers, Ramps/Arduino, cheap chinese display, etc) from an old 3d printer project I had (it was a printer I was going to rebuild but I wasn’t sure how to make a more rigid frame after I took it apart with the tools I have). I currently need to perform some mods on my current 3d printer in order to start printing all the parts I need but I do have some questions I was hoping to get some help with.

    -Pipe, does it matter if it’s schedule 80 or 40? Is one any better than the other for this project?

    -Size, I’ve never seen a clear answer on this and I suspect it’s because pipes that will be holding the weight of the tool head will flex a bit one way or the other depending on your tool and the material being worked. I’d like to use this on wood initially and I’d like to be able to get a full sheet of plywood up to 3/4 inch in there. Has anyone made this size? What are the “gotchas” I need to look out for?

    -tool head, I see that the dewalt is the preferred tool for milling here but I was wondering if something a bit heavier, like my porter cable 5.6 amp 30Krpm flush trim router which comes in about 4 lbs? Not that much heavier, but I want to know if that will cause more flex? will it need more reinforcement?

    -I see talk of Lasers. Are these lasers that are being purchased for $100 capable of cutting 1/4 inch plywood? Or is this something that is just being used to etch? I have seen great etching with them but I haven’t seen any posts of anyone trying to cut wood with one. Also, I read a question from someone asking if it can be used to cut acrylic but never saw an answer. Has anyone had success with this?

    -I plan to mount it on a large board (which may actually limit me to < 4×8 sheets of plywood) and put it on a system to pulley it off my garage work bench when not in use. Anyone have any experience with moving one of these? or does everyone just mount it directly to a table for the added rigidity?

    I have other questions rattling around in my brain but they just aren’t coming to me right now.

    Thanks in advance

    #13688

    Daniel Huss
    Participant

    -Pipe, does it matter if it’s schedule 80 or 40? Is one any better than the other for this project?

    I wouldn’t guess so as long as the outer diameter is the right size. With the size you’re looking at, the thicker walls seems like it would be a better bet.

    -Size, I’ve never seen a clear answer on this and I suspect it’s because pipes that will be holding the weight of the tool head will flex a bit one way or the other depending on your tool and the material being worked. I’d like to use this on wood initially and I’d like to be able to get a full sheet of plywood up to 3/4 inch in there. Has anyone made this size? What are the “gotchas” I need to look out for?

    That’s pretty big… here’s the first one in build forum I found that’s pretty close: https://www.vicious1.com/forum/topic/test-run-of-the-7-5-foot-x-4-foot-mpcnc/ Looks like he added an extra set of grantry pipe to make the middle more rigid. Try looking through the build forum for some more.

    -I plan to mount it on a large board (which may actually limit me to < 4×8 sheets of plywood) and put it on a system to pulley it off my garage work bench when not in use. Anyone have any experience with moving one of these? or does everyone just mount it directly to a table for the added rigidity?

    I saw one a while ago where they put it on a hinge to fold it up against a wall when they weren’t using it. If I remember correctly though, it was more in line with the recommended size.

    #13689

    Lou Spinuso
    Participant

    Thanks, that’s very helpful. Looking at those additional rails to help with the head seems like it will take away a bit of milling space, I’ll have to think of ways to make that work out better. I just ordered a new Y carriage for my 3d printer and if that resolves my leveling issues (it should as I can visibly the current cheap carriage bend while trying to adjust the leveling screws) I’m going to start printing the parts I need right away (I’ll grab a small piece of schedule 80 pipe to make sure things fit nicely) and stock piling them so I have everything ready when it cools down enough to build in my garage again.

    Thanks again.

    #13691

    Ryan
    Keymaster

    I would say if you are going big, stick with conduit. It is thin walled and rigid, low moving mass.

    Are you going to be cutting 4×8 parts or just don’t want to cut down a full sheet? You can easily make a full sheet pass under it and slide the sheet down each cut. I have never really seen any giant parts cut ever.

    It isn’t necessarily the weight of your tool but also the distance your spindle is offset from the gantry. The dewalt has plenty of power and it is pretty compact. If you stick a giant tool on there it increases the gantry lever arm and significantly reduces rigidity.

    The laser would take at least 2 passes to cut 1/4 ply, but maybe the new higher powered one would do it faster? Not sure. 1/4 ply mills much faster than a laser cuts it, I believe that is why most only etch with them.

    If you are going to use pulleys build a nice torsion box and you will be fine.

    #13695

    Lou Spinuso
    Participant

    Thanks, so you think conduit would be suitable for a CNC of that size?

    I want to go full sheet because I’m hoping to be able to use it to cut wood out of full sheets to make cabinets and boxes more accurately than I get when trying to manhandle a large sheet through a table saw by myself. Also, with a CNC mill, I should be able to have less waste cuts as I should be able to fit pieces in ways that I wouldn’t be able to using traditional tools. tbh, I think I will mostly use it for 1/2 and 3/4 inch ply though I do see a time in my future where I’ll probably use it on boards (once my building skills with wood increase). I’ll definitely have to give it some thought.

    using laser on 1/4 is more of a question. I like the etching (I’d love to put some personalization on some pieces) but if I have some really tricky, small details, sharp corner cuts that need to be made, it’s nice to know that the laser might be able to pull it off. Though again, not even a remote priority, just more of a curiousity.

    And great idea on the use of a torsion box. That should keep things rigid enough to stay flat.

    Thanks again

    #13696

    Ryan
    Keymaster

    Hard to say I have not built one that big. I always suggest conduit though. Anything larger than 3′ should use midspan supports. You are months out from a a build so maybe someone will do a large build by then.

    As for the laser I have not tried the new stronger one so I could not say for sure. You will have to deal with charred edges though.

    #13719

    Lou Spinuso
    Participant

    Yeah, I figured as much with the laser. Looks like my new Y carriage gets here on Saturday, so early next week my printer should be just cranking out printed parts.

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