MPCNC Lowrider initial squaring and maintenance

New Home Forum LowRider Advice – LowRider MPCNC Lowrider initial squaring and maintenance

This topic contains 3 replies, has 2 voices, and was last updated by  Jeffeb3 1 week, 4 days ago.

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  • #113399

    Mark Selig
    Participant

    Hello all,

    I have a few questions for the group as I looked on the regular page and did not find what I am looking for.

    1.  What are the steps for squaring this machine?  My thoughts are to drop Z to its lowest point without the router in place and verify that all for contact points are even.  Take the x to its minimum and maximum travel and verify that the x is square, and then do the same thing with the y.  Measure from X full Travel Y full Travel, to X Home Y  Home, and do the same for the opposite corner to verify that it is all square.  Once I do that Put a mark at center of table with my Pen in the pen holder, and make repeated moves a given distance(Such as 10MM each direction making a square and verifying the size, and verify it can do it consistantly.  How to tune that is a mystery to me.  If everything is square, and it moves to the locations I tell it, great, but if it is off a little how do I tune it.
    2. Once I have it tuned fairly, I plan on making the two Y plates and the 611 plate on the machine, and tearing it completely down to start over on my assembly, making sure I get it all square again.  I would like to at that point put on a fresh spoils board, and then do a wipe pass on it.
    3. What other calibrations do I need to make on the machine?  Am I on to the right path of making sure this is set up correct?
    #113404

    Jeffeb3
    Participant

    If you don’t have dual endstops (which most people don’t on the LR), then you need to start the motors with the machine square, and as long as it doesn’t skip steps, it will stay square. This is how I start square. It all starts with my table, which I know is square (enough):

    – I manually pull the machine to the front edge of the table.
    – I have some stop blocks I attach to the front edge of the table and I pull the gantry up against them (The front of my table runs parallel to the tubes).
    – I give each Z leadscrew a half turn to lift the gantry up, and it gently falls back down. This will remove any springiness in the couplers.
    – The gantry location doesn’t matter much, but I’ll pull it all the way to the left side, so I can hope to recover if there is some kind of power outage or skipped steps.
    – I hold the gantry against my stop blocks while I send a movement command. This starts the motors and then I can remove the blocks.
    – I move the machine around, setting up the job with the motors/jogging. Before I set the G92 origin, I write down the values of the X, Y, Z and if I get really into trouble, I can hope to get close again by starting in the corner, and moving to these coordinates before issuing the G92 again.

    I do this every time I start the machine. It’s proved pretty reliable to me, reliable enough to fix jobs that went wrong.

    As for verifying the squareness, you can just move the machine with the G1 commands or with Repetier host or the LCD, whatever. If you draw a 3-4-5 triangle, or just the points of the 3-4-5 triangle, you can measure the lengths of the side, and make sure they are indeed 3-4-5. So if you drew a point at 0,0, then at 90, 0, then at 0,120, the distance between 90,0 and 120,0 should be 150mm. If you don’t have a pen mount, you can plunge the router bit in 2mm and make a mark that way. It’s harder to verify the Z is moving perpendicular to the XY plane. I guess I have always just assumed it with my LR.

    If it’s not square, then look at your startup procedure and the table for errors. You can shim the starting blocks or if there’s a way the rails have gotten out of square, then square them up.

    Regarding 2) Sounds good, although I would say you should do as many jobs as you’re comfortable with before you tear it down. That way, you’ll have some frame of reference to know if it helped, and it will help if any new issues show up after rebuilding it.

    Regarding 3) You’re doing more than most. You should be good to make a bunch of dust already.

    1 user thanked author for this post.
    #113408

    Mark Selig
    Participant

    I know I am a little (OK A Lot) overboard with start up procedures, and why would anyone make a Start Up Procedure with a checklist?  Will it is just the way I am.  I have a start up procedure for my 3d printer and it is working great and works for the most part every time,  If it does not it is easy to find out why, and get back up and running really fast.  I want to be able to use this machine for a wide array of different things, and so far, it appears like it will do everything I plan to ask of it.

    #113419

    Jeffeb3
    Participant

    My day job is writing software for robotics. One thing I’ve learned: Humans are terrible at repeated tasks. A checklist makes a lot of sense. I have definitely forgotten steps because I’ve never written mine down. I should…

    1 user thanked author for this post.
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