Problems with z-distortion on my printer

flydeprutten

Hello.

I am new to this forum, but I have used the repetier firmware for a few months now on my new printer.

Over the holiday I have tried to get z-distortion to work, but I have some problems with the result. If I make a height map in repetier-host, it looks really good (+0.01mm), but when I'm printing something, it does not look good. Each line segment starts low and moves slowly upwards. As I can see it, the line starts at the right height but ends in the uncorrected height.

I use a CoreXY layout on my printer, with a 200 x 280 mm bed. I have saved my distortion map in my EEPROM and my configuration looks like this:

#define DISTORTION_CORRECTION 1

#define DISTORTION_CORRECTION_POINTS 10

#define DISTORTION_CORRECTION_R 100

#define DISTORTION_PERMANENT 1

#define DISTORTION_UPDATE_FREQUENCY 10

#define DISTORTION_START_DEGRADE 0.5

#define DISTORTION_END_HEIGHT 1

#define DISTORTION_EXTRAPOLATE_CORNERS 1

#define DISTORTION_XMIN 0

#define DISTORTION_YMIN 0

#define DISTORTION_XMAX 180

#define DISTORTION_YMAX 260

My Z-probe configuration looks as follows:

#define Z_PROBE_Z_OFFSET 0

#define Z_PROBE_Z_OFFSET_MODE 0

#define UI_BED_COATING 1

#define FEATURE_Z_PROBE 1

#define Z_PROBE_BED_DISTANCE 6

#define Z_PROBE_PIN ORIG_Z_MIN_PIN

#define Z_PROBE_PULLUP 0

#define Z_PROBE_ON_HIGH 0

#define Z_PROBE_X_OFFSET -35

#define Z_PROBE_Y_OFFSET -3

#define Z_PROBE_WAIT_BEFORE_TEST 0

#define Z_PROBE_SPEED 2

#define Z_PROBE_XY_SPEED 120

#define Z_PROBE_SWITCHING_DISTANCE 5

#define Z_PROBE_REPETITIONS 3

#define Z_PROBE_HEIGHT 0

#define Z_PROBE_START_SCRIPT ""

#define Z_PROBE_FINISHED_SCRIPT ""

#define Z_PROBE_REQUIRES_HEATING 0

#define Z_PROBE_MIN_TEMPERATURE 150

#define FEATURE_AUTOLEVEL 1

#define Z_PROBE_X1 20

#define Z_PROBE_Y1 20

#define Z_PROBE_X2 180

#define Z_PROBE_Y2 0

#define Z_PROBE_X3 20

#define Z_PROBE_Y3 260

My z-probe is 1.45mm higher than my hotend, but I always compensate it manually after the printer has auto-leveled the bed with the g-codes:

G00 z-1.45

G92 Z0

I have attached a picture of the problem.

Is there anyone who can help me with my problem?

/Hans

Repetier

#define DISTORTION_EXTRAPOLATE_CORNERS 0
is better. That was meant for deltas that can not reach edges of a rectangle.

You also provided the answer to the problem:

#define DISTORTION_START_DEGRADE 0.5

#define DISTORTION_END_HEIGHT 1

G00 z-1.45

G92 Z0

That is ugly and most likely causes problems with everything and completely not needed. Just set

#define Z_PROBE_HEIGHT 1.45

or do it in eeprom editor which you must override otherwise. Redo G32 S2 and G33 and see ho wit works then.

flydeprutten

ahh. That makes a lot of sense. I've overlooked that part of the configuration. I presume it should be:

#define DISTORTION_START_DEGRADE 0

#define DISTORTION_END_HEIGHT 0

Thank you :smile:

I've only set the z-probe height to 0 temporarily, as I'm still working on the printer, and have already experienced a height change after I made a change to the printer. After which the printer tried to make the first layer 0.5mm down into my aluminum bed. That was not good for either the bed nor the extruder nozzle. :|

/Hans

Repetier

#define DISTORTION_START_DEGRADE 0

#define DISTORTION_END_HEIGHT 0

No, the values were good.
Start degrade is when it should start reducing and you want at least one layer with full correction. Above end height it will do no correction at all.

flydeprutten

Oh, but then I do not understand why my first layer looks like it does. Is it supposed to have those big differences in the first layer, that can be seen in the picture?

Repetier

Looks like you are too close in general in the picture.

Roko

Are your probe offsets correct?A suggestion, go to a certain X,Y coordinate and mark the bed (lets say X50, Y50). Then do a g30 to the same coordinates. If your probe x,y is right you will touch in the same spot with the probe. You might be probing the wrong places ( slightly off).

flydeprutten

OK. I will try to optimize my z-probe to see if it helps.

Thanks for the help. :)

mikebarjak

Hi, Did you resolve your above issue? I am having similar problems

flydeprutten

Sorry, no.

I simply could not figure out what the problem was, and my bed is too uneven to avoid distortion correction. I worked with the problem over a few weeks, and tried, what I think was everything. That's why I eventually switched to another firmware.

I'm sorry that I can not be of more help. :/