Why "printing in air" can appear, alerady from start of model 3d drawing??!

RomanVK

Hello everybody! Have a good time of day!

I got cheapest in the world Flsun Kossel Delta 3D printer with MKS base 1.4 (8828) board that i screwed with my best abilities to be happy owner. I'm got configured Repetier firmware and calibrated at openDact differencial "David's star" of Escher's algorhytm to have acceptable values. I'm using Slic3r to prepare my models for 3D printing, and have a good G-code to work.

So, I'm have an issue of "printing in air" from concrete start of 3d print. I makes a lot of checks and corrections I am tried, but have nothing at all. Every time of tenths of tries to print something I got only crazy effector in air.

Dear Repetier firmware and specialists of other sciences, please tell me some kind of ideas what to do, to fix this bug, and thank you very much, right now, mates?!

Repetier

Make sure you have always check endstop option disabled. If you get crosstalk to endstops during print moves will not finish correctly and result is random and wrong positions. So better only use endstops for homing and then ignore the signals.

Hope it is this. Alternatively the trigger wrong during homing causing wrong start condition.

Last is loosing steps.

All only if it normally works so you can assume correct configuration in general.

RomanVK

Repetier wrote
Make sure you have always check endstop option disabled. If you get crosstalk to endstops during print moves will not finish correctly and result is random and wrong positions. So better only use endstops for homing and then ignore the signals.

Hope it is this. Alternatively the trigger wrong during homing causing wrong start condition.

Last is loosing steps.

All only if it normally works so you can assume correct configuration in general.

Thank you! I'm use
#define always_check_endstops 0
And now my calibration becomes more correct! But I am still have printing problem: when I'm start to 3D print effector comes near the bed but not so close, and start printing in the air. Im just corrected Z-height by sheet of paper and checked it, using Repetier-host.
A bit later I'm found that on back on home command steppers doesn't turns off when comes to endstops. So I'm get back
#define always_check_endstops 1
And..... OOOOPS! I'm still have NOT WORKING ENDSTOPS.... then I'm found that one of endstops looking broken...

RomanVK

Woah... Idk what happens, but now my optical endstop turns on light when Im takes column of printer where its located. This happens only with one optical diode and column, wo other works fine and proper.
Ouuu... yeah.. Im fixed endst soop by reattaching it, so problem still old... printing in air, by ununderstoodable problem...
I'm back to this ferature
#define always_check_endstops 0
because it's works well...

Show you part of G-code that I'm sliced to print:

M107

G92 E0

M190 S115 ; set bed temperature and wait for it to be reached

M104 S235 ; set temperature

G28 ; home all axes

G1 Z5 F5000 ; lift nozzle

; Filament gcode

M109 S235 ; set temperature and wait for it to be reached

G21 ; set units to millimeters

G90 ; use absolute coordinates

M82 ; use absolute distances for extrusion

G92 E0

;G1 Z0.294 F7800.000

G1 E-2.00000 F2400.00000

G92 E0

G1 X8.656 Y-8.656 F7800.000

G1 E2.00000 F2400.00000

G1 F1800.000

G1 X8.656 Y8.656 E3.11139

G1 X-8.656 Y8.656 E4.22278

G1 X-8.656 Y-8.656 E5.33416

Repetier

Cod elooks good except
;G1 Z0.294 F7800.000
which prevents head going down making it print at 5mm height.

RomanVK

<a rel="nofollow" target="blank">Repetier</a> said:

Cod elooks good except
;G1 Z0.294 F7800.000
which prevents head going down making it print at 5mm height.

Ok! Finally I'm started printing, after calibrating Z-heightr again from printer's menu... And print becomes 19,55x19,40, and have vertical curves at founding.
Thank you again for your opinion and answer:
#define always_check_endstops 0
Next stage is to do test cube's planes correct. So another one question: what is your opinion, how to make identical moves for X, and Y, axises till 3D printing? I see that in firmware's code are strings of regulation steps per mm for each motor, but now can't imagine how to translate them to decart's coordinates.
Now I have 102 steps/mm for each axis => new medium value are (102 x 20)/19.47 = 104.7 = 105 steps/mm for each axis, but how to play with different values for axis?

RomanVK

Thank you very much Repetier! Im going to create new subj for questions c u soon :) bye bye

Repetier

Actually in this version we assume same steps for all 3 axis taken from z, so it is a must that these are equal which normally is the case if they use same belt/idler/tension.

But deltas a difficult to calibrate. The escher tool optimizes for bed getting planar also geometry is completely wrong. This can cause xy to become wrong insted which the z probe can not measure. So best is to ensure angles, distances of diagonal rods and horizontal radius are correct. Any physical improvement will reduce geometry errors.