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MrMik
(@mrmik)
Honorable Member
Print bed size or location inaccurate

I have a problem with the location or size of a large object on the print bed.

According to OpenScad and Slic3r it should fit, but on the actual Prusa i3 bed it misses a corner.

I noticed only now that I had the same problem with firmware 3.0.8 : A large plate I printed is only 208mm wide instead of 210mm, I never noticed it before.

See pictures below for details.

I figure that maybe the printable area is 210mm, but is not being used at the front edge of the bed.

Any suggestions how to fix this would be much appreciated.

Cheers, Mik

Postato : 22/01/2017 10:52 pm
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Print bed size or location inaccurate

Could someone with a Prusa i3 MK2 try to print this ellipse, please?

It should just fill the print bed to touch the sides, but on my printer there are always a couple of mm missing at the rear edge.
No need to print the whole thing, just set Slic3r to 0mm skirt and tick "External perimeters first". That way, you only need to print a single ring until you know if your printer can print 250mm x 210mm, or not.

I would very much like to know if this is maybe due to the way I built the printer, and/or if it affects others.

Please let me know! 🙂

OpenScad code for the test object:

$fn=180;
linear_extrude(3)
scale([125,105,0])
circle(1);

Postato : 24/01/2017 12:11 pm
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Print bed size or location inaccurate

I found the cure for this problem:

Change bed size in Slic3r > Printer settings > Bed shape > Set > Size: x: 250 Y: 205 (change Y from 210 to 205)

I played around with changing the Y: Origin setting, but to no avail.

Setting the print bed 5mm too short makes Slic3r overlap the object by 2.5mm on front and back.

Happy camper 😀

Postato : 24/01/2017 9:26 pm
Carsten
(@carsten-2)
Estimable Member
Re: Print bed size or location inaccurate

Interesting! Maybe the position of the Z Assembly does not match quite?

Carsten

My Prints: https://www.prusaprinters.org/social/15695-carsten/prints
My Employer: https://make-magazin.de

Postato : 25/01/2017 10:49 am
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Print bed size or location inaccurate

Interesting! Maybe the position of the Z Assembly does not match quite?

Carsten

But with all the auto-calibration going on, I think that would be compensated for.

Postato : 25/01/2017 1:15 pm
Carsten
(@carsten-2)
Estimable Member
Re: Print bed size or location inaccurate

I can move:

X: 0mm (exactly the leftmost line, endstop activated) -- 251mm (exactly "eyeballed" rightmost line) --> 255mm (4mm outside bed)

Y: -2mm (where the intro line is) ZERO (at the frontmost line) -- 207,3mm (3mm before 210mm line)

So the movable area is really 210mm but printable area is 207mm which may confuse slic3r. So I wonder did you enter -2mm at the Y Origin to test?

Carsten

My Prints: https://www.prusaprinters.org/social/15695-carsten/prints
My Employer: https://make-magazin.de

Postato : 25/01/2017 2:09 pm
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Print bed size or location inaccurate

I can move:

X: 0mm (exactly the leftmost line, endstop activated) -- 251mm (exactly "eyeballed" rightmost line) --> 255mm (4mm outside bed)

Y: -2mm (where the intro line is) ZERO (at the frontmost line) -- 207,3mm (3mm before 210mm line)

So the movable area is really 210mm but printable area is 207mm which may confuse slic3r. So I wonder did you enter -2mm at the Y Origin to test?

Carsten

I tried adjusting the Y origin by -2mm but it did not change where the ellipse was being printed. I tried multiple different variations (manually moving it in Slic3r, auto arranging, just importing STL beore or after setting Y origin differently) but I could not influence the print location in any way by those methods.

The 250 x 205mm trick works, printable area is 250 x 210mm then; my surfboard-fin print is running and no edges are missing.

Postato : 25/01/2017 2:22 pm
Carsten
(@carsten-2)
Estimable Member
Re: Print bed size or location inaccurate

Yep just tried and my print also got capped at about 208mm Y-Axis. I mean the object was complete (as yours) but there are 2mm missing.... Strange behavior. Like "if y>208 then Y=208"

Carsten

My Prints: https://www.prusaprinters.org/social/15695-carsten/prints
My Employer: https://make-magazin.de

Postato : 25/01/2017 2:32 pm
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Print bed size or location inaccurate

Yep just tried and my print also got capped at about 208mm Y-Axis. I mean the object was complete (as yours) but there are 2mm missing.... Strange behavior. Like "if y>208 then Y=208"

Carsten

Thanks for trying it out!
🙂

Postato : 26/01/2017 6:34 am
Vojtěch Bubník
(@vojtech-bubnik)
Utenti Admin
Re: Print bed size or location inaccurate

The current XY skew calibration code shrinks the available print bed area a bit, if the X and Y axes are not perfectly perpendicular.

Postato : 28/01/2017 12:03 am
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