Auto Bed Compensation probs

Hi All,

I've just set up DC42's sensor board and am tweaking all of the config files. The final problem I have is that when I do Auto Bed Compensation the Z0 is too high, if I restart and do a Home all then Home Z it's fine, but after a ABC a Home Z causes the Z to be too far off the bed. Any thoughts? bed.g attached.

M561
G1 Z10 F200
G1 X50 Y25 F3000
G30 P0 Z-100000
G1 Z10 F200
G1 X50 Y190 F3000
G30 P1 Z-100000
G1 Z10 F200
G1 X205 Y190 F3000
G30 P2 Z-100000
G1 Z10 F200
G1 X205 Y25 F3000
G30 P3 S Z-100000
G1 Z10 F200
G1 X125 Y105 F3000
G30 P4 S Z-100000
G4 P1500 ; Leave the probe there to give the web interface time to report the plane points
G1 Z10 F200

Hi,

Not sure what you mean by "after an ABC"
If you home the z-axis after the X and Y. Is the z-height correct? I.e is has a slight pull upon a trapped sheet of paper.
After you run the auto compensation the console should display a string of values at each point, please can you copy that into this post.
As we can see if your print bed is flat and level, if not this could be the reason for the z-height being too high, at the start of the print (I think)

Chris

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Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

Quote
unstable
Hi All,

I've just set up DC42's sensor board and am tweaking all of the config files. The final problem I have is that when I do Auto Bed Compensation the Z0 is too high, if I restart and do a Home all then Home Z it's fine, but after a ABC a Home Z causes the Z to be too far off the bed. Any thoughts? bed.g attached.

M561
G1 Z10 F200
G1 X50 Y25 F3000
G30 P0 Z-100000
G1 Z10 F200
G1 X50 Y190 F3000
G30 P1 Z-100000
G1 Z10 F200
G1 X205 Y190 F3000
G30 P2 Z-100000
G1 Z10 F200
G1 X205 Y25 F3000
G30 P3 S Z-100000
G1 Z10 F200
G1 X125 Y105 F3000
G30 P4 S Z-100000
G4 P1500 ; Leave the probe there to give the web interface time to report the plane points
G1 Z10 F200

First of all your bed.g is wrong. See the marking. Second I would try to run only 4 points:

M561
G1 Z10 F200
G1 X50 Y25 F3000
G30 P0 Z-100000
G1 Z10 F200
G1 X50 Y190 F3000
G30 P1 Z-100000
G1 Z10 F200
G1 X205 Y190 F3000
G30 P2 Z-100000
G1 Z10 F200
G1 X205 Y25 F3000
G30 P3 S Z-100000
G1 Z10 F200
;G1 X125 Y105 F3000
;G30 P4 S Z-100000
G4 P1500 ; Leave the probe there to give the web interface time to report the plane points
G1 Z10 F200

The S parameter is to save the settings after the last point.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Sorry I was being lazy, 'after an ABC' = after an Auto Bed Compensation.

Console output is interesting:

10:19:06 PMBed calibration error: 0 points provided but only 3, 4 and 5 supported
10:18:55 PMBed equation fits points [50.0, 25.0, 0.050] [50.0, 190.0, 0.009] [205.0, 190.0, -0.507] [205.0, 25.0, 0.062]

If I home X, then Y and finally Z the nozzle is touching the bed. If I do a G32 and then Home Z the nozzle no longer touches the bed.

I suspect the problem is that you still have the homing files set up to home Z in one corner, but you are now running 5 point bed compensation. Try changing the homez.g and homeall.g files to home at the centre of the bed. Recalibrate your G31 Z height at the centre of the bed, and remove the white squares at the corners of the bed if you still have them.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

The main problem is that he uses two times the "S"-parameter. One after the fourth point and one after the fifth point. At first he should fix this and report the behaviour after that.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Thanks Treito, that seems to be the problem.

Latest output : Bed equation fits points [50.0, 25.0, 0.217] [50.0, 190.0, 0.173] [205.0, 190.0, -0.467] [205.0, 25.0, 0.115] [125.0, 105.0, 0.140]

Quote
dc42
I suspect the problem is that you still have the homing files set up to home Z in one corner, but you are now running 5 point bed compensation. Try changing the homez.g and homeall.g files to home at the centre of the bed. Recalibrate your G31 Z height at the centre of the bed, and remove the white squares at the corners of the bed if you still have them.

Yep I went through them, all seems to be working now, it looks like I copied and pasted the last G30 command and didn't see the S.

Does the compensation persist across restarts? Or is it something I should do before every print? Up until now I've never used it, just homed XYZ and printed.

Compensation does not persist across restarts, although there is a mechanism to define compensation amounts in config.g if you want.

I only use bed compensation when doing large prints. For small prints I just re-home Z in the centre of the bed when the bed and nozzle are hot, just before printing.

Edited 1 time(s). Last edit at 02/07/2016 05:49PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Sounds good, thanks. And thanks for the board, it makes a huge improvement to the printer. Now I just need to install my ALU X arm.

Quote
unstable
Thanks Treito, that seems to be the problem.

Latest output : Bed equation fits points [50.0, 25.0, 0.217] [50.0, 190.0, 0.173] [205.0, 190.0, -0.467] [205.0, 25.0, 0.115] [125.0, 105.0, 0.140]

I would get all these values to be 0.1 or zero by manually levelling the print bed with an object of known height but then as you are replacing the x-arm you are going to need to perform the Bed Plane Compensation and then Orthogonal Axis Compensation print and set the values in the firmware to get good prints and the above will improve.
The worse points to get to be zero are the two near the 3rd mount point.
I normally run the Auto Bed compensation at the start of every print and check the output of G32 first thing.
As for some reason when I run at the start of a print the above is not shown in the console.

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Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)