MPCNC with no legs.. Instead on a MDF box?

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This topic contains 25 replies, has 6 voices, and was last updated by  Ryan 1 week, 3 days ago.

Viewing 26 posts - 1 through 26 (of 26 total)
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  • #49559

    Ciaran Whelan
    Participant

    Hi there, I am constantly fixing the little tightening lugs on all my corners as they seem very prone to cracking. I cannot tighten them too much as they crack, but also can’t blame them for cracking as they are just little things holding the clamps in place.

    What I was thinking is making a complete box section for the tubing to sit on with custom corners to hold the tubes all in place in the box or on top of the open top box section. Has anyone done similar and dumped the legs all together? If so I would love to see any pictures of how they have done this. If not then is there any negatives in exploring this path?

     

    #49561

    Jeffeb3
    Participant

    Huh. That’s interesting. I am assuming your just talking about parts in the corners, not entire sides? Can you extend the pipes and just support those with some wooden towers? If you leave the corners installed, then you don’t have to mess with the belts.

    #49562

    Ciaran Whelan
    Participant

    I am thinking of redesign of the complete corner to corner with a box section with poly carbonate inserts to MDF. That way remove all the corners and design new corners to attach to the inner corners of a box. Obviously a not so tall box, maybe 150mm tall sides, with printed outer joiners.

    I was hoping I could get my hands on a MPCNC as Fusion360 file. Has anyone designed the complete machine in Fusion for remixing?

    #49564

    atmonaut
    Participant

    You might look into building a flat MDF top with a square center cut-out, and then building the box underneath to lower the cutting area.  Then you can use the dimensional analysis here to get your measurements for your own polycarbonate corner blocks, I found these dimensions to to be extremely accurate and worked for me.

    https://www.thingiverse.com/thing:1459025

     

    #49571

    Ryan
    Keymaster

    The corners don’t really do anything and should need hardly any tension on those screws.  My rails can rotate on the corners, you just need them so the belt tension can not pull them together.

    The corners linked above are similar to the very first versions I made. We used electrical conduit boxes for feet and legs, sounds funny but actually worked very well. I switched for two reasons, the embedded nuts had everyone underwear in a knot and if the prints weren’t really good the bottom piece being shaped like a C would flex open and actually offset the top enough to cause tension in odd places. So if you use them they are great just make sure your printer is in good shape.

    Or you can print the corner pieces out of another material, petg? Just take it easy on the tension as it shouldn’t be needed.

    As for the new design your thinking of, I would love to hear more. As for dimensions there really are only two you need to worry about the rail to rail distance is a tiny bit different for all three machines, and the belt location is basically along the inside edge of the top of the rail (as in it rides on the bottom of the bearing that rides on the top of the tube).

    I am starting to feel the very strong urge for a redesign but at this point it will take some serious time.

    #49584

    Derek P
    Participant

    I built a U channel plywood box using the standard corners:

    Machine base and spoil board

    It works OK but doesn’t provide a significant improvement and access is slightly worse.

    #49618

    Ciaran Whelan
    Participant

    This image doesn’t really help too much. But art the very basics all I need is end collars, and incorporate the right height for the belt ends. I then have a way to attach inside an MDF box. I then no longer need the legs or end joiners at all.

     

    The lityle orange collar is just me mocking up an idea while I design how I will do it.

    My critical dimensions are the spacing of the tube away from the sides being 30mm to allow clearance of tge carriages. The height of the belt tensioner from the centre line of the tube. I think those two are all I actually need to ensure are correct

    Other than that the next is to ensure the pipes are all parallel and at equal heights. Hence the collars can simply screw into place rather than boring holes  the MDF for the pipes to sit into.

    into

    Thoughts on these parameters addressed above?

    #49622

    Ciaran Whelan
    Participant

    This is what I have in mind for a full boxed enclosure. What you don’t see is that the front panel will have a cutout for a poly-carbonate insert to go in the mdf frame like a window. That was my kids can see without getting any hands in the area at all. It will contain any little cuttings this way as well. I still have to design up the end collets that will fasten to the MDF sides, and incorporate the belt fastener ends.

    Please feel free to add your thoughts on how I can design these end collets and keep them fairly simple.

    #49626

    Barry
    Participant

    I think the little orange collar will work.  Make sure you seal the MDF real good though.  It will move on you throughout the seasons.  Hardest part will be squaring it all up and keeping the spacing.

    #49627

    Ciaran Whelan
    Participant

    I have a good 2 pack sealer which I will spray with 2 coats between sanding. I 5gem have 2 pack auto paint in gun metal grey in satin. I will use my corner bracing that I use in furniture making tho get this square on each corner sand fasten with 50mm Deming screws to pull the corners together, and hide those under the printed corner braces.

    At the bottom I will make 18mm corner fillets in the internal corners. I will then make a few cross braces out of 18mm which the spoil board can screw down to.

    I think with those things being done I should have a very sturdy base for my pipework to sit into. My one concern is the box section may amplify the cutting noise like a speaker.

    My other concern is getting the belt tensioner ends in the right place. I will probably model the end clamps with built in belt tensioner similar tho how they are on the sides of the clamps.

    Do we have these corners somewhere in fusion360? If so it will save me time remodeling something that was already done. If not I will just model up new ones.

    I wanted to see what the corner braces look like on top of the dark grey. I got lazy and faced the MDF a quick brush with no sealant so I could see the colours together.

    #49679

    Ciaran Whelan
    Participant

    Corner collets now designed and printed. These work fantastic and are to the right dimensions for offsetting the belt tensioner. Am pretty happy so far. I will create the box over the weekend and brace it up to see how it goes together. I am not worried about not being able to get access to it inside once boxed as I will drop hinge the front panel.

    #49681

    Ciaran Whelan
    Participant

    And attached is the printed end collet. I have just screwed it to a scrap piece of MDF

    #49694

    Derek P
    Participant

    What are you planning for cable management?

    #49704

    Ciaran Whelan
    Participant

    Thin black sticky back electrical conduit boxing.

    #49934

    Ciaran Whelan
    Participant

    Box painted and looking ready for second fitting.

    #49937

    Ryan
    Keymaster

    WOW that looks pretty dang good so far.

    #49938

    Barry
    Participant

    Yea, I’m digging it!

    #50017

    Ciaran Whelan
    Participant

    I a.m. getting that little bit closer.  I took it all apart this morn8ng after ferrying everything lined up perfectly to give the box another coat of polyurethane. One thing I noticed is that if any of your rails on tge sides are off by a fraction it turns the center into a seesaw type action. I didn’t realise but one of tge little spacers between the pipes had a bit of dirt stuck in it so it had one side offset by about 1mm. Enough to throw off alignment. Tge way o have designed three little pipe ends allows you to rotate the pipes enough to give some adjustment up and down. With the little bit of dirt removed it has fixed my small issue.

    So far I have the center in and will rewire soon. I just ordered some black sticky side conduit that I will hide my wiring into, as well as a couple of cable trays to get the XY into. I have not used cable tray before so it will be interesting to try work out.

    #50019

    Ryan
    Keymaster

    Are you going to cut openings or anything in the sides? How are you going to get material in the box?

    #50020

    Ciaran Whelan
    Participant

    I will cut a drop down side tomorrow.  I will also route a recess into the drop down for some plexiglass to sit in it. Still a bit to do.

    #50021

    Ryan
    Keymaster

    cool

    #50045

    Ciaran Whelan
    Participant

    For those nor on the FB group.

     

    A bit more progress today.
    I have decided this morning not to add a drop down panel at the front since the space above allows me to place my cutting material from the top. I may change my mind one this when I get to use the machine over time.

    So this morning I finished aligning all 2mm stainless tubes, fitted the emergency stop to the box, fitted belts, redesigned the Ryobi router clamps and printed them, I completely realigned the center section/carriage so that the T8 lead screw can literally wind down on its own weight.

    What I am really pleased with is that I am not chasing ways to get the corners to stop wobbling with the legs. I think by seeing that many remixed of corners to beef them up to stop any movement triggered my little alarm to think of a better way to mount a fantastic design such as the MPCNC.

    What is next on the list:
    1. Wire up the steppers
    2. Retest my possibly faulty mini Rambo
    3. Wire up my grbl CNC Shield
    4. Make a spoiler board
    5. Make a flexible overhead arm for vacuum
    6. Install cable chains
    7. Install internal LED lighting
    8. Design LED spindle ring
    9. Design and install misting nozzle for alloy
    10. Source a cheap bath for 3mm carbon cutting
    11. Add a nice big MPCNC vinyl sticker to the front.

    #50047

    Ciaran Whelan
    Participant

    Anti vibration rubber squares.

    #50051

    Ryan
    Keymaster
    11. Add a nice big MPCNC vinyl sticker to the front.

    I put the new logo files up on the information>Logo File,  page! Just a suggestion.

    I love the things you are trying here. I have some new ideas for sure because of it. There are a few builds where they have the XY rails right on the box edges. Similar to yours but a bit different. I have not started any new parts yet but you are definitely getting me excited to get my butt in gear on some new parts.

    #50068

    Ciaran Whelan
    Participant

    Thank you Ryan for your kind words. However your branding is more about your business direction, wgilst i want tho keep the simple lettering MPCNC on the machine front. I hope you don’t mind.

    I will be making my design files on Thingiverse “MPCNC Boxed”. Now that it is built i will tweak the corners as i notice that the belt tensioners are off by 1.5mm.

    I will also adjust the centerline of the cantelever on the pipes as well to give that adjustment without the pendulum effect.

    #50087

    Ryan
    Keymaster

    I have no problems with that at all.

    I can’t wait to see it in action, you are getting so close.

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