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Re: M2 Auto-Leveling

Posted: Wed Apr 08, 2015 3:24 pm
by DaveSL
STEP would be nice to allow modification to the design.
Josh wrote: .......

Let me know if I've missed anything here, or if you would like .STEP or other formats for the parts.

Re: M2 Auto-Leveling

Posted: Wed Apr 08, 2015 3:53 pm
by DaveSL
Are there plans in the works for some type of deploy/retract system to automate the process? Micro servos weigh next to nothing. TAZ is using a x endstop bump system for its probe deploying.

My other question is the Z "after print freefall" going to knock the Z stop switch out of alignment if its relocated to the bottom. Even with gcode scripts in place for a gentle descent, there are times when "stuff" happens. I placed rubber grommets around the Z stepper shaft to act as a safety catch, but I think it might interfere with accurate Zstop calibration readings.

Re: M2 Auto-Leveling

Posted: Fri Apr 10, 2015 5:38 am
by nelsond6
Hi guys. I finally attempted this auto bed leveling feature. So far from my limited testing, it seems to work.

Here is a video of it in action. Sorry about my elementary video editing skills...

Like Joe, I had to only modify my z probe offset value. I also just moved the z endstop to the bottom of the printer, so the bed just triggers the switch lever but doesn't put any pressure on the switch body when the bed is in its resting position.
My bed is purposely not level on the x axis in the video. Notice the Z knob constantly moving when printing the layers. I am printing a scaled up version of the bed leveling probe rotated in the x axis for my first test. I printed all the probe mounts in PETG Blue and Red. Also, I usually would have my 50 mm fan going during the print, but it died a few days back, so that is why you don't see it in the video. The print still came out pretty good without it.

Things to note:
1. The probe mount blocks the filament tension screw. Maybe a easy fix would to turn the screw around so you could tighten it from the opposite side.
2. When the probe is in its locked position, it barely clears the nozzle. I probably have to fiddle more with the probe spring and the screw locking position to fix this, but for now the clearance gets me by.
3. I had to sand down the wire clip holder on the side of the extruder mount in order to get the probe mount on. Not a big deal, but something to note.
4. Having to remember to manually interact with the probe screw to move it up and down is not great, but it works for now. Like Dave said, you would probably want some sort of servo/retract in place. I was going to work on this once I get my hands on a servo this weekend. Anybody have any experience wiring up a servo to the Rambo board and controlling it with gcode?

Here is the starting gcode I used in S3D:

M108 S255 ; turn on M2 fans
M851 Z-9.4 ; set probe offset for z
G28 ; home all axes
G29 ; probe the bed
G4 S10 ; pause for 10 seconds to lift bed leveling probe screw and to lock it in place
;start the purging of the nozzle
G1 Y50 Z0.3 F9600 ; move forward to avoid binder clips
G1 X205 Z10 ; move off platform
G1 Z0.4 ; position nozzle
G92 E0 ; zero extruder
G1 E50 F225 ; purge nozzle
G92 E0 ; zero extruder
G1 X190 Z0.1 E1.0 F1200 ; slow wipe
G1 X180 Z0.25 ; lift

I would say if you are doing fine with your bed leveling and z height adjustment just stick with that, but for some reason I always have troubles leveling the bed and I hate having to adjust that z height bolt, so I will stick with this auto bed leveling for a while and see how it goes.


Re: M2 Auto-Leveling

Posted: Sun Apr 12, 2015 9:25 pm
by Farr0wn3d
It's quite possible that I'm missing something here, so please take these suggestions for what they are worth.

I find that I am having to constantly adjust my bed for level, and its usually because I'll begin a print that is turning out like shit and when I check the bed for level and distance in relation to the nozzle tip, it seems to always be out to some degree. I'm not sure how this is possible because I even do my adjustments with the nozzle part way to temp to account for thermal growth (only part way, 135 degrees C, anything more and the nozzle oozes and complicates things)

When it comes to leveling the bed I would really like to see the adjustment points further from the center of the bed. When you're dealing with clearances in the tens/hundreds of microns, we would benefit from finer adjustment and that can really only be accomplished by moving the points further from center because we're already working with a very fine thread adjustment medium. Not only that but if vibration or shocks bump the adjustment screws at all it will make less of an alignment impact if they are further from the center, ideally right at the edge if possible.

I would also prefer to see the 3-point adjustment system discarded in favor of a 2-point adjustment system. What I mean by this, is if you have a fixed ball joint in the center of the bed (center of both X and Y axes), and height-adjustable ball joints located at max X and Min Y, it would take the guesswork out of adjustments that affect all planes, and you could focus on each axis at a time. this could also be adjusted with mini-stepper motors which could be controlled via the software with the readings from the multiple Z-height probings that previous posts have mentioned.

Sidenote: I've designed a dial indicator holder that clears the v3b, and utilizes the 2 bottom mount screws that mount the extruder to the drive motor. Its for a 3/8" stem, and should be compatible with 1/2" and 1" travel indicators, as well its as close to the nozzle as possible. The indicator must have the flat back plate however. If anyone is interested I can post up the .STL

Re: M2 Auto-Leveling

Posted: Mon Apr 13, 2015 11:44 pm
by Lateralg
Bed Leveling drove me nuts until I decided to understand the geometry. Now it's no big deal.
1- Adjust Z reading over North screw to match South screw.
2- Adjust East screw to same level as North & South screws. Done.
3- East-West can be improved a bit by then measuring near X=0 & X=200, making them equal.


Let's try this Zip file.

Re: M2 Auto-Leveling

Posted: Sat May 02, 2015 7:59 am
by Developer69
@wrenches, can you post the .stl file for the dial indicator holder. Also a few pictures would be nice and part number of the dial indicator you use.


Re: M2 Auto-Leveling

Posted: Mon May 04, 2015 2:45 am
by Farr0wn3d
Heres the .STL, the model number of the dial really isnt necessary since any dial with a flat back and 3/8" stem will work with this, I've tested the 1/2" and 1" travel models and they both work well. Keep in mind that this is very close to the hot end so you really cant use this when the hot end is on or the bottom portion starts to flex and your readings get unreliable.

Okay so as it turns out the extension .stl isnt allowed to be attached so if you PM me your email I can email you the file

Re: M2 Auto-Leveling

Posted: Mon May 04, 2015 12:50 pm
by PcS
You can .zip it and it will post .

Re: M2 Auto-Leveling

Posted: Mon May 04, 2015 3:35 pm
by Developer69
Looks like I cant PM you. If you can either try and PM me or add it as a .zip file here as someone suggested.

Re: M2 Auto-Leveling

Posted: Mon May 04, 2015 4:35 pm
by insta
argh how are you both in the restricted group but still not showing up as needing moderated posts