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Print not centering on build plate

Posted by Shank man 
Print not centering on build plate
May 26, 2018 04:39PM
Hello, I’m absolutely stymied and need some help. I’m not sure if this is a printer, firmware or slicer issue but I’ll post my problem here. The printer is a HyperCube CoreXY. RAMPS 1.4, Marlin 1.1.0-RC7 and g-code created with Slic3R. Pronterface is the host..The motors turn in the right direction and the axes all home as they should The problem is that the printer will not center the print on the bed. Every print start right at the home position, right at the front left hand side of the plate. While the printer is going through the motions it is triggering the X & Y end stops.

The printers X & Y travel limits are X250 x Y230, My printable area is set at 200 x 200. The extruder tip homes about 5mm to the front and left side off of the printable area so I set the offsets (origin in the bed setup) in Slic3r to -25 & -25. Pronterface shows the print starting up and to the right. If I’m reading the G-code right it also has the extruder traveling up and to the right to the bed center. I even tried setting the Slic3r offset setting to positive numbers and that had no effect. All I’m trying to print is a 100mm cubejust to check the motions. I haven’t actually printed anything yet, Its a new build.

I’ve read everything I could find but just can't seem find a solution.

Any suggestions or help is greatly appreciated.!

Ray

Config_H.doc

G-code.txt






Re: Print not centering on build plate
May 27, 2018 03:05AM
You have to set the origin in Marlin and slic3r the same way. ( eg. bed center at 0,0 )
IMHO you have to set slic3r offset to +105,+105 and leave Marlin as_is.

BTW: You can disable autocenter parts in slic3rs preferences, just to get you printing. Just move the part to a position, your printer can actually print it.

Edited 1 time(s). Last edit at 05/27/2018 03:08AM by o_lampe.
Re: Print not centering on build plate
May 27, 2018 10:15AM
Quote
o_lampe
You have to set the origin in Marlin and slic3r the same way. ( eg. bed center at 0,0 )
IMHO you have to set slic3r offset to +105,+105 and leave Marlin as_is.

BTW: You can disable autocenter parts in slic3rs preferences, just to get you printing. Just move the part to a position, your printer can actually print it.


Thank you for the suggestions, I tried both and still get the same results. The print continues to start at the home position regardless of where I place it in Slic3r.I tried Cura too and there is no difference so I'm guessing there are some settings in the firmware I'm missing.The firmware was preconfigured and included in the Thingiverse file with the printable part STL's. For now I changed the print area in Marlin and Slic3r to be the same and re-positioned my end stops so the nozzle homes over the print area. At least now the filament will land on the bed surface.
Re: Print not centering on build plate
May 28, 2018 12:59PM
Where is the bed located within that 230x250 mm space? The printer thinks of motion in its coordinate space, and the slicer has its own coordinate space shifted (usually) relative to the printer's coordinate space. The slicer's origin is always on the corner of the bed. The printer's origin may or may not be on the bed.

Take a look at this: [drmrehorst.blogspot.com] and this: [drmrehorst.blogspot.com]

Slic3r is usually pretty easy to set up, Cura a little harder because you have to use some custom gcode to tell it where the origin of the bed is located.


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Print not centering on build plate
May 30, 2018 06:08PM
Quote
the_digital_dentist
Where is the bed located within that 230x250 mm space? The printer thinks of motion in its coordinate space, and the slicer has its own coordinate space shifted (usually) relative to the printer's coordinate space. The slicer's origin is always on the corner of the bed. The printer's origin may or may not be on the bed.

Take a look at this: [drmrehorst.blogspot.com] and this: [drmrehorst.blogspot.com]

Slic3r is usually pretty easy to set up, Cura a little harder because you have to use some custom gcode to tell it where the origin of the bed is located.

I should have titled my topic differently. I should have said " All prints start at the origin regardless of the Slicer settings."

I never had any problems getting the prints centered on the Prusa I2 & I3 style printers so I thought this might be a CoreXY issue. I printed
out your tech topics a few months ago, they are a tremendous help. Thank you for taking the time to write and post those.

All the motors are turning correctly, all limit switches are
connected to the minimum pins on the controller board.

the slicer generated g-code has the nozzle moving to X70 & Y70 to start the print


G28 ; home all axes


G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0
G1 E-1.00000 F1800.00000
G92 E0
G1 Z0.350 F7800.000
G1 X70.350 Y70.350 F7800.000
G1 E1.00000 F1800.00000
G1 X169.650 Y70.350 E10.02931 F378.000

Pronterface indicates the same when I load the file......

the print goes from 70.200000 mm to 169.800000 mm in X
and is 99.600000 mm wide

the print goes from 70.200000 mm to 169.800000 mm in Y
and is 99.600000 mm wide


but the prints always start right at the origin. the extreme lower left of the 3rd quadrant.

my next move is to try a different firmware version.
Re: Print not centering on build plate
May 30, 2018 09:23PM
When you load you stl file in the slicer, where does it show it in the plater view? Is it centered on the bed or is it at the corner?


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Print not centering on build plate
May 31, 2018 03:05AM
...reminds me of my first few prints, where the parts came out mirrored. I had defined the endstops wrong and reversed the steppers to get it "right".
The firmware didn't allow negative coords for XY too.
This might be the problem in your case: the nozzle is in the negative quadrant after homing and FW refuses to move it.
What are your bed limits in FW? In RRF it's the M208 S1 X### Y### Z### line.

Edited 1 time(s). Last edit at 05/31/2018 03:07AM by o_lampe.
Re: Print not centering on build plate
September 20, 2018 01:03AM
Did you solve the problem, cause mine is exactly the same. Every print so far started in the right bottom corner triggering the endstops of x and y, no matter even if the offset postions in marlin were changed.
Re: Print not centering on build plate
September 20, 2018 06:30AM
Did you solve the problem, cause mine is exactly the same. Every print so far started in the right bottom corner triggering the endstops of x and y, no matter even if the offset postions in marlin were changed.[/quote]

In my case all I had to do was increase the voltage to my X stepper. I turned the potentiometer a little and the printer started behaving normally. It seemed
odd that it worked great by just jogging the axes but not when it came time to do a print. I was a little embarrassed by not being able to figure it out for a couple days so I didn't post the fix to conclude this thread.


Prusa I2
Gen7-ARM 2.0 / Teacup
Genuine J-Head Mk V-BV

Hypercube
RAMPS 1.4 / Marlin
E3D V6

Piper 1 Version 2
Gen7-ARM 2.0 / Teacup
E3D V6

MPCNC
RAMPS 1.4/ Marlin
Re: Print not centering on build plate
September 20, 2018 07:12AM
No problem your response is still appreciated. And this could be of help too, cause what i recognized is that there is this loud sound right after heating is finished it seems like mine missing out the way to the defined print point somehow too but then for the print running "normal" except its alway that corner. Doesn't look like a configuration problem, so I will try to play with the vref and comment back.
Re: Print not centering on build plate
September 20, 2018 09:41AM
It's pretty easy to guarantee that the print centers on the build plate with any slicer/printer if you set the printer's origin to the printable center of the bed plate. I previously linked a blog post on setting up a corexy machine's origin at the FL or RR corners and then configuring slicers. That required some custom gcode to get Cura set up properly. Since then I have rethought the problem and come to the conclusion that center origin is better because it doesn't take any custom gcode tricks to make the slicers work that way. I wrote another blog post about that type of set-up here. Of course, it assumes that the printer's mechanism is working properly...


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Print not centering on build plate
September 20, 2018 10:20AM
Quote
the_digital_dentist
Of course, it assumes that the printer's mechanism is working properly...
Yes the problem is i don't think so, because when printing in the corner and hitting one of the endstops it tells position on pronterface and this differs slightly sometimes for ex. y coordinate is shown triggered endstop at 97.5 or on another try at 96.7. so the mechanismn isn't working probably.

But still thanks for the useful link
Re: Print not centering on build plate
September 20, 2018 12:07PM
So i solved the problem by switching back to a previous marlin version, neither turning vref up nor down did help
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