visible 3 steps in part of larger prints

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visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-09-Jun

Hello community

I need help with a strange behavior with my new Printrbot maker kit which works great except for this (potentially software based) bug
Two larger objects I have resized or rotated and printed using Cura 15.04 show 3 visible "steps" or X offset. When i print the object twice, the steps happen again in the same place (just to make sure it wasn't a random accident)

I'm thinking this is a Cura bug more than anything else but I didn't find any sign of it in the forums or the Cura github so I was curious as to whether there is experience with the people on this forum.

Thanks!
Stephane
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visible 3 steps in part of larger prints

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Re: visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-09-Jun

trying to post pictures and links to source to illustrate. Any idea how to link to pictures or files as a new user?
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Re: visible 3 steps in part of larger prints

Postby PxT » 2015-Jun-Mon-12-Jun

How to post photos: viewtopic.php?f=7&t=6771
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Re: visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-13-Jun

See pictures and files attached.
The rodin statue has the 3 steps offset between knees and butt, The STL file is attached as well
The gremlin status has the 3 steps offset on the ears. The STL file is 50MB, if you want to download it, just search for Gimli in Tingiverse
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Re: visible 3 steps in part of larger prints

Postby RetireeJay » 2015-Jun-Mon-13-Jun

It looks like these objects may have exceeded the build boundaries of your printer. The maximum size limits in X and Y extend all the way up to the top of the Z travel. If the printer tries to move beyond the maximum (or negatively beyond zero) then it won't actually go there, but it loses the steps that would have taken it there.
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Printrbot Plus operational January 2013
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PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
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Re: visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-14-Jun

Thanks for looking into this Jay but I doubt it's even close to the upper limit from the printrbot maker's kit. In the case of the Rodin statue, the problem manifest itself almost exactly in the middle of the statue at apprx. 1.5 inches high. Aside from this defect, the rest of the statue (about 4 inches high) printed incredibly well and smooth.
Is there a way in Cura (or using some export tool) to see what the expected 3D outcome would have been according to the data Cura is going to send to the printer (if that makes sense)
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Re: visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-14-Jun

I should add I am using the Printrbot simple makers kit template from Cura that shows a printable area of 100mm in every direction (not sure if that's a known incorrect setting)
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Re: visible 3 steps in part of larger prints

Postby RetireeJay » 2015-Jun-Mon-17-Jun

xs32 wrote:In the case of the Rodin statue, the problem manifest itself almost exactly in the middle of the statue at apprx. 1.5 inches high. Aside from this defect, the rest of the statue (about 4 inches high) printed incredibly well and smooth.


Perhaps I wasn't clear. It wouldn't matter if your model was only 1/4 inch high. Height has nothing whatsoever to do with the problem I was describing. It's how far in X and Y that your printer has to travel to make the model. It's clear that your models grow larger in X and Y as you go up in Z. And in the case of the Rodin statue, it looks like the knees are where the print reaches its maximum extent in the X-Y plane. What are the maximum dimensions of your model in X and Y (the slicing program should tell you what the maximum X and Y are)? In other words, if you had the sun directly overhead, would the shadow of the (good) print go outside the printable area of the bed?

xs32 wrote:I should add I am using the Printrbot simple makers kit template from Cura that shows a printable area of 100mm in every direction (not sure if that's a known incorrect setting)


You need to have your maximum dimensions set to agree with each other everywhere. That means in Cura and also in the EEPROM (M211) settings of the printer. If you are using Repetier, set the maximum bed dimensions there, too.
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Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
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Re: visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-17-Jun

Got it. Thank you for your patience and wisdom. Cura says the object size is X:72mm Y:48.84mm Z:97mm
I can't answer your question about whether the shadow would go outside of the printable area (it's not obvious to me what it is looking at the bed) but the problem areas are indeed towards the limit of where the printer prints.
M211 returned nothing but M501 returned this:
> M501
< echo:Stored settings retrieved
< echo:Steps per unit:
< echo: M92 X80.00 Y80.00 Z2020.00 E96.00
< echo:Maximum feedrates (mm/s):
< echo: M203 X125.00 Y125.00 Z5.00 E14.00
< echo:Maximum Acceleration (mm/s2):
< echo: M201 X2000 Y2000 Z30 E10000
< echo:Acceleration: S=acceleration, T=retract acceleration
< echo: M204 S3000.00 T3000.00
< echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
< echo: M205 S0.00 T0.00 B20000 X20.00 Z0.40 E5.00
< echo:Home offset (mm):
< echo: M206 X0.00 Y0.00 Z0.00
< echo:PID settings:
< echo: M301 P22.20 I1.08 D114.00
< echo:Min position (mm):
< echo: M210 X0.00 Y0.00 Z0.00
< echo:Max position (mm):
< echo: M211 X100.00 Y100.00 Z115.00
< echo:Bed probe offset (mm):
< echo: M212 X25.00 Y0.00 Z-1.10
The M211 settings seem to align with the ones from Cura (100mm in every direction).
Does this help confirm we're dealing with an XY plane dimension issue? If so, should i calibrate the bed or modify a printer setting in Cura?
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Re: visible 3 steps in part of larger prints

Postby RetireeJay » 2015-Jun-Mon-18-Jun

Well, OK, you've got me convinced that my hypothesis is all wet. Your object SHOULD print without running afoul of the boundaries. I don't have another theory to suggest.

Unless... the print is not centered. There must be a setting in Cura somewhere that says where to place the center of the print, and that should be at 50, 50 from the dimensions you gave. Also, some people have encountered problems with the print starting off-center due to some mysterious mumbo-jumbo with the bed probing sequence. I don't have that stuff, so I can't easily tell you how to troubleshoot that. But basically, the print (all of it, not just the base) should be centered on the bed. If you dropped a vertical line from the statue's knees as printed, would that line be well within the bounds of the printable area?
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Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
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Re: visible 3 steps in part of larger prints

Postby Mach-Chris » 2015-Jun-Mon-20-Jun

RetireeJay wrote:Well, OK, you've got me convinced that my hypothesis is all wet. Your object SHOULD print without running afoul of the boundaries. I don't have another theory to suggest.

Unless... the print is not centered. There must be a setting in Cura somewhere that says where to place the center of the print, and that should be at 50, 50 from the dimensions you gave. Also, some people have encountered problems with the print starting off-center due to some mysterious mumbo-jumbo with the bed probing sequence. I don't have that stuff, so I can't easily tell you how to troubleshoot that. But basically, the print (all of it, not just the base) should be centered on the bed. If you dropped a vertical line from the statue's knees as printed, would that line be well within the bounds of the printable area?


WRT Mumbo jumbo, as far as I have figured, in my experience anyways, is that the M212 X25.00 is what tends to shift the prints from the desired centre of the bed. My best guess is that the autolevel routine is supposed to be using this offset value to better map the bed relative to the nozzle, since the probe IS roughly 25mm X+ from the nozzle. However, it would seem that what ends up happening (according to a post I found, reddit I think ) is that the machine's position ends up being shifted at the conclusion of the probing routine. SO, in light of that, there are a few options you have here. One would be to play with the M211 X value (ex: M211 X10.) and print some test prints, and wash, rinse,repeat until you find values that result in your print being in the same position as Cura slices them in. The other option, is to put an M92 in your "starting gcode" sequence AFTER the G29 that will actually reset where the printer thinks it is. To do this you would have to read off the echo positions of the probing routine, and do some math to figure out where is SHOULD think it is. If I recall correctly from my playing around in the configuration.H file of marlin for PBSM. the default probe Inset from max X travel is 10mm which would mean that If you have 100mm x travel, the probing routine would probe its last point at X90. You should still double check these numbers yourself though.

Good luck!
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Re: visible 3 steps in part of larger prints

Postby xs32 » 2015-Jun-Mon-20-Jun

You figured it out both of you. Although you must be half blind to miss it, I didn't realize I was always printing off the bed center by 15mm so the M212 X10 (didn't forget to save!) was the fix. Seeing that now there are a numbers of online threads about printrbot off center problems and a number of G29 suggestions (none of which worked for me because all printers are different), it appears to me this is a known issue affecting a number of printrbot (potentially other) people. I wonder why the Printrbot firmware comes out of the box with this offset of 25 (M212 X25.00 Y0.00 Z-0.20) rather than 15 --- maybe good feedback for the product team. Anyway thanks to both of your for your time and help and patience. Looks like I'm good to print larger models in good conditions.
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Re: visible 3 steps in part of larger prints

Postby RetireeJay » 2015-Jun-Mon-21-Jun

I'm not sure, but I think another solution is to do a G28 X0 Y0 command AFTER the G29 command. This resets the X and Y zero positions without affecting the Z correction. But I may be off-base on this; let us know if that works.
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Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
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