Delta Calibration firmware for atmega + ramps 1.4

Hey everyone,

I have a delta 3d printer running on atmega 2560 + ramps 1.4.
I have achieved good results by manual calibration or by using the amazing escher 3d wizard from dc42.
But I havent had good success with auto calibration so far.

Which Marlin firmware should I go for ? Marlin 1.1.x or Rich cattell's Marlin ?

Has anyone tried the manual probing of marlin 1.1.x to level the bed ?

Please help.

What unsuccessful auto calibration FW did you use?

Marlin 1.1.x now includes auto calibration for deltas (G33); you have to enable it in configuration.h; uncomment #define DELTA_AUTO_CALIBRATION.

Edited 2 time(s). Last edit at 05/11/2017 01:35AM by LVD.

Hi LVD,
Thanks for your amazing work in the AC firmware. I have used the AC firmware provided in the example_configurations of marlin 1.1.x

Here is what I have done:
1) I did not find the correct z probe offset so I kept it 0. Now I run the G33 P6 C0.03 as autocalibration command. The calibration is done in 7-8 iterations.
2) Because I kept the offset 0, after calibration, I manually set the Z-Height.
3) Now as expected it should print a good first layer. But it does not. At one point on bed it prints well, at another point on bed it tries digging into the bed and scrapes.
4) When I manually check the calibration at the base of the towers, it is not equal. At one tower its above the bed, at another tower its into the bed.

5) So i did a M502 - M500 - G33 P6 C0.03.
6) The firmware gives me the same calibration solution again.

Where am I going wrong ? Do I need to find the right z probe offset and do auto level after auto calibration ?

Just for information: Is manual probing not compatible with deltas to use auto leveling ?

Auto-level is tilting the bed and is conflicting with auto-calibration; this is like putting the bed on springs in order to calibrate the end-stops. Since you're still using the C0.03 parameter you must be using a pretty old version of the AC-firmware; there has been a bug with the z-offset, but that seems to be solved now. Better get the latest version at [github.com] or if you want the latest of the latest go check out [github.com]. And do not change the calibrated height, but trim it with the z-offset parameter (M851). Manual probing at the towers should give the same results as displayed with verbose level 2 (G33 P2 V2). When probing more points (G33 P6) you should compare results with manual probing the same 36 points.

Yes, I have uploaded the following firmware: [github.com]

I did a 7x7 point auto-calibration by using the following command: G33 P7 V2
Z-offset value: -0.35
It resulted in a std deviation of 0.008 after 8 iterations.

echo:busy: processing
. c:-0.00 x:+0.01 y:-0.00 z:+0.00
. yz:-0.01 zx:-0.01 xy:+0.00
Iteration : 08 std dev:0.008
.Height:307.52 Ex:-2.22 Ey:+0.00 Ez:-0.53 Radius:154.74
.Tower angle : Tx:-0.02 Ty:-0.91 Tz:+0.00
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
. c:-0.01 x:+0.02 y:-0.00 z:+0.01
. yz:-0.01 zx:+0.01 xy:+0.00
Calibration OK rolling back.
.Height:307.52 Ex:-2.22 Ey:+0.00 Ez:-0.52 Radius:154.75
.Tower angle : Tx:-0.04 Ty:-0.93 Tz:+0.00
Save with M500 and/or copy to Configuration.h

Then I manually probed 7 of the 49 points (near towers, opposite towers and center)
Here is the result:

Center: -0.55
Tower Z: Near: -0.2 Opposite : -1.3
Tower X: Near: -0.9 Opposite : -0.3
Tower Y: Near: -0.8 Opposite : -0.3

What could possibly create such a huge error ? Can pulley dimensions or belt tolerance cause this ?
I feel the error is possibly in tower Z, because the errors are symmetric in tower X and Y.

Edited 1 time(s). Last edit at 05/12/2017 10:10AM by VJain.

I manually probed the 7 points and put them in the escher 3d wizard made by dc42.

This is the result shown:
Endstop X -2.3 Y-0.28 Z0
Tower angle: X-0.39 Y-0.32 Z0
Delta Radius 153.73
Height 308.06

So I inserted these values in the firmware and did a M500.

And then I cross-checked and probed the 7 points again. This is the result I got:

Center: 0.00
Tower Z: Near: 0.0 Opposite : -0.05
Tower X: Near: 0.05 Opposite : 0.00
Tower Y: Near: 0.0 Opposite : 0.00

Thats with 100 micron flatness. So what must be going wrong with auto-calibration ? I am very much confused now. Please help.

Could you post the output of M420 V

>>> m420 V
SENDING:M420 V
echo:Bed Leveling Off

It just says bed levelling off every time I send M420 V.

Am I missing something ?

Trying to figure out why manual probing gives different results to probing in G33; there was one guy with the same problem, it disappeared when he switched to the latest FW [github.com]

Uploaded the latest firmware and did auto calibration.
When I cross checked by manually probing, the error is still there.

Please let me know when you find out what causes this error.
Until then I will be using dc42 calculator. But I really want the auto-calibration to work.

Thanks

Probe the same points with auto-calibration and the manual check; so use G33 P3 V2 and do your check manually on the same radius that was set with M665 Bx.x on exactly the same points.

dear lvd
where we can found a manual for this new marlin features?
it s a it hard for non users to understand everything...and if you are not english is a hard way

Marlin doc here in the Wiki

Hi,
I'm struggeling with G33 too,
when I send G33 I get message M665 Bed radius implausible

I'v increased or lowered
#define DELTA_PRINTABLE_RADIUS 130

but I'm always getting M665 Bed radius implausible


If I run Delta Calibration from LCD
I can only run set Delta Hight and X,Y Z separatelly
and not Auto Calibration


I'm stuck
Any advise will be most welcome

Regards
Mario

reduce DELTA_CALIBRATION_RADIUS or more easy without recompiling set it with M665 Bxx.x

LVD Thank You,
I already reduced DELTA_CALIBRATION_RADIUS. to 80
After your replay I reduced ro 60 and now it works

I have one more question regardin G33, do I have to execute any other command
after running G33 or are the new measurements already saved to EEPROM

Regards and thanks

MArio

M500

Hi LVD
Couldn't work out recently.

But found these parameter:
OD of 20 teeth GT2 pulley (measured including the teeth)

1) Pulley 1 - 12.18 mm
2) Pulley 2 - 12.18 mm
3) Pulley 3 - 12.28 mm

Can this affect the calibration process ?