I’ve always wondered how Z homing would work with the LR. I typically use a small carpenter square, one edge flat on the spoil board then lower the Z assembly until just touching with the router close to 0,0. Then I’ll move X to the max positive value and adjust the right side Z leadscrew by hand until the router mount is touching again. Move the router back to 0,0 and double check Z height.
Is there an easier way you know about?
I’ve been meaning to draw up a rest that I could slip under the X rails so that when the steppers die and the X gantry falls, it rests level. But, alas, I choose the hard way…
With the LR2, in order to use homing to square the Z axis, it homes to the top of the travel, but goes down when using the touch plate to determine Z=0
Homing in this case is more accurately squaring the machine. To do this, we need to have a consistent spot to go to where we can be assured that both locations are an equal distance from a reference point.
To home Z downwards would be difficult, to say the least, unless you are always going to have the same tool in place (like an extruder, for example) and you would need to test in 2 known locations to be able to level the motors. Easier to place 2 switches in known locations, where you can always get there, and never need to go past. Going towards the table, a longer tool will prevent you from getting there, and a shorter tool might require you to go past the switches, or cutting into the spoilboard to be sore you go through your material.
Thanks Dan,
i agree that this is more of a squaring process rather than homing. Squaring is exactly what i am trying to achieve! I also ordered the touch plate for homing prior to start the cut (which i still havent gotten around to yet). Ill need to get some parts designed or downloaded to mount the switches for z squaring.
Appreciate the help!
FWIW, I don’t use dual endstops on my LR. I just start the motors while the sides are resting on the bottom. My LR has a 4’ span. I can get within a mm. That’s pretty good too me.
Pick up a pair of inexpensive mass-produced items while you’re cogitating on your rest design. I used to tomato paste or soup cans to level the two ends of the X axis on my Prusa clone before I upgraded to the version of Marlin that supports auto Z levelling. They were identical in height to the precision available on my (admittedly not stellar) digital calipers.
Thanks Jeff, i also assumed that starting in the fully lowered position would be suitable for leveling. However, since i already have the equipment purchased, i figured why not add the functionality with the end stops (if it ends up being to much of a pain, i can always disconnect).
Tom i also agree, my next thought would be to 3d print a cradle or spacer that i could put on both ends of the X axis tubing. they would help to level but also prevent the carriage from bottoming out in the z direction. when i disconnect power, one of my steppers always wants to bottom out and im not sure why. as such, my machine always sits skewed after powering down.
I worry about that in theory, but in practice, I’ve found that they’re definitely close enough.
Even when there’s a measurable difference (One has too much “squish” in the first layer, for example) the actual difference becomes irrelevant quickly.
Even then, if you use the X or Y axis for your more precise measures, you’ll be accurate to within one motor step for sure, and almost certainly better than that. Chances are that your accuracy is the accuracy of your filament, adjusted for your nominal extrusion width. Better than my calipers at least.
So i have run into a new issue.
I can home X, however when trying to home Z, only the E1 (Z2) motor will move until the end stop is actuated. I have the Z2 drive connected to E1 on rambo V1.4 port and the end stop connected to the Xmax port.
Z1 (which wont actuate while homing) is connected to the Z port on the rambo, and its end stop is connected to the Zmax port.
Ive ensured that end stops are not using the positive terminal(S and - only).
On a side note, if I try to move any axis of the machine, it works as expected.
Could this be a damaged endstop, damaged board or something like software/firmware or just plain old user error?
My Rambo V1.4 was recently flashed with V1CNC_Rambo_DualLR 2.0.7.2-2.0.7.2 / 510.
Sorry Dan, unfortunately I haven’t gotten as far as looking into code (I wanted to get the end stops wired and parts printed/set up before starting to learn the code/commands). I have yet to read into this portion of the low rider. All movements/commands have been through inputs via the hand held screen.
Edit: i can access the code via Visual Studio Code and the platformio extension. when i do a cntrl F for M114 no results are found. I did not edit the this code, so maybe that line needs to be added?
You will need to access the control board via the USB serial port, and send the command to it. M114 is a Marlin Gcode command that reports the status of the endstops. It should list all of the stops and whether they are in open or triggered status.
This is going to be the next step in debugging the endstops.
Control board was wired correctly, however the wires running from the steppers on opposite side of my machine were not.
Long story short, the z end stop was mistakenly connected to Y stepper (FACEPALM).
I’ll try to figure out the repetier host commands next and report back on m119 vs m114.
Hey Guys, figured id keep this post going.
Based on the image that Dan posted, i believe my Y axis should be flipped to follow the right hand rule (this means my origin moves to the opposite end of my machine - no big deal just need to move Y end stops to opposite end).
i generated my GCode file, placed my paper, and lowered the Z so its about touching the paper.
when i hit run in repetier host, my machine bottoms out in the negative z direction (it also moves in the wrong y axis direction, but thats due to my issue above). am i wrong in assuming that positive Z lifts the gantry away from the workpiece?
the toolpath shows above the surface, and the crown is shown below the surface (when viewing in repetier host).
there is a note on the tutorial page that suggests my z motor wires may need to be flipped. I think this is odd because my machine auto levels by raising the x gantry (flipping would cause it to autolevel by moving downwards).
Positive Z axis should lift the gantry away from the bed surface.
Estlcam by default will have a “clearance plane” at Z=5 (This is configurable) and it will go there between cut moves. The cut moves will be at the depth set.
You can try Ryan’s GCode for the test crown and then at least you have a known good source code. My LowRider handles a pen worse than my kids did when they were toddlers, so mine looked like garbage but still confirmed that I’m getting correct movement from the machine itself.
I think i may have resolved the issue. dont want to say a problem with the gcode, but i believe the first few lines of code were trying to move my machine to a point below the table surface. mostly to do with the machine not knowing where it was (imo, im still learning). i removed some of the lines and added a command to define where the tool was starting from (G92 x0,y0,z0 if i recall correctly). i have "successfully drawn the crown a few times, but my maker is moving on me as its only held by a single zip tie). ill print up a holder tomorrow if i have time and try with a pen. baby steps!
Got mixed up there.