MPCNC Lowrider initial squaring and maintenance

LowRider CNC Advice
#1

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?
#2

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.

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#3

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.

#4

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…

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#5

OK So I finally got a few to get back to my Lowrider 2 today. I have the Y plates (The ones with the wheels on them) square to one another and now it will travel the Y from one end to the other. The X axis on the other hand is an issue. Yes it is able to travel from one side to the other with no problems but one side of my 611 plate is level, but when it gets to the other side of the table it is way unsquare. How do I adjust the plastic part to make it level? One side is like 1/2" or so higher on that side of the table. I want to be able to adjust it, and then run my crown test tomorrow. Thought I would ask here before I went out there and messed with it as that side of the table is tough to get at to begin with. Once I get it level, I should be ready to run my crown test, and then bolt the router on. From there I plan on doing two video’s One of the machine doing the crown test and one with the machine going from X0,Y0,Z0 to full X Full y and Full Z then traveling to X0 Full Y Full Z and then moving to Full X Y0 Full Z and then from there going to X0 Y0 Z0. That will show full range of motion. Then it is a matter of buying a sheet of material, and buying the Bits and I will be ready to make a new pair of Y plates and a 611 Plate and rebuilding the whole thing. From there I will be ready to start using it.

 

On a side note, a couple of parts after I printed all of my Lowrider 2 parts I broke my extruder on my 3d printer so that has been my slowdown as I had to find my spare parts, and then rebuild and calibrate my printer. As we speak it just finished the last calibration cube (A calibration cat) and is all back up and running) The printed extruder that came with my printer has lasted over 5 years now. I think it did its job and I am glad it is back up and running. I did not realize how much I missed having a printer.

#6

Do you mean thw Z is higher on one side than the other? Does it fall all the way down when it’s off? My first problem like this was I forgot to lube the screw.

Can you share a photo that explains it?

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#7

Look at the distance between horizontal where the vertical bars for the Z connect

[attachment file=117690]

Now look at the close side

[attachment file=“117691”]

It has a twist in the x from side to side. Not sure how to adjust this out of the machine

8BF64E68-A609-4C27-B9AC-F0971627C1A5.jpeg
8BF64E68-A609-4C27-B9AC-F0971627C1A5.jpeg4032Ă—3024 1.52 MB

6513AD54-06D0-44C0-97CA-AEAD0F22FFDB.jpeg
6513AD54-06D0-44C0-97CA-AEAD0F22FFDB.jpeg4032Ă—3024 1.66 MB

#8

If you loosen the XZ corner caps on both sides that should fall into place. If it does not chances are really good your Z rails are not parallel for some reason.

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#9

Thank you Ryan. I will try that first thing tomorrow. Before I put them on the Y plates Y thought I had it right but things sure were moving around.