Printing artefacts: cause and remedy?
Posted by dc42
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Printing artefacts: cause and remedy? April 17, 2014 06:20PM |
I've noticed that certain features in a model being printed cause artefacts such as small steps elsewhere in the model at the same z-height. In order to pin this down, I created and printed a simple model, then rotated it 90 degrees and printed it again. The results were very similar.
I'm wondering what the cause might be:
1. Mechanical? I don't think it can be belt slippage or a stepper motor missing steps, because there are no permanent steps in the piece. Looking at the photos of the ends, one side is more or less vertical, the other is not.
2. slic3r issue? As far as I can see, the positions of the X and Y extremities are the same throughout the gcode file. I haven't checked whether the extrusion rates are also constant.
3. Firmware? Could it be causing the XY positions at the end of a move to be out by a substantial fraction of a mm, the amount depending on the size of the move, only to be corrected when it moves back?
4. Cooling? Could it be that in the seconds after a section of perimeter has been printed, depending on the subsequent head movement the rate of cooling varies, and this in turn affects the width when the extruded filament solidifies?
5. Something else?
I would be interested to know whether other users see the same thing, and whether other 3D printers display the same effect.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
I'm wondering what the cause might be:
1. Mechanical? I don't think it can be belt slippage or a stepper motor missing steps, because there are no permanent steps in the piece. Looking at the photos of the ends, one side is more or less vertical, the other is not.
2. slic3r issue? As far as I can see, the positions of the X and Y extremities are the same throughout the gcode file. I haven't checked whether the extrusion rates are also constant.
3. Firmware? Could it be causing the XY positions at the end of a move to be out by a substantial fraction of a mm, the amount depending on the size of the move, only to be corrected when it moves back?
4. Cooling? Could it be that in the seconds after a section of perimeter has been printed, depending on the subsequent head movement the rate of cooling varies, and this in turn affects the width when the extruded filament solidifies?
5. Something else?
I would be interested to know whether other users see the same thing, and whether other 3D printers display the same effect.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Printing artefacts: cause and remedy? April 17, 2014 08:28PM |
Hello dc42,
I've always blamed retraction and travel speed for these artifacts, although I guess printing speed and cooling play a big role as well,
Usually I print ABS only, but because my PSU was broken til today I switched back to PLA for the moment. However, when printing ABS, I can't discover this kind of artifacts at all. Just for comparion, here's an ABS-printed part for my replacement alu bed:
And here is your test piece printed with PLA:
This makes me think your firmware is working properly, but perhaps the last layer of laid PLA doesn't cool down quickly enough and deforms when retraction is triggered. Out of curiosity, what do your extruder settings in Slic3r look like?
I've always blamed retraction and travel speed for these artifacts, although I guess printing speed and cooling play a big role as well,
Usually I print ABS only, but because my PSU was broken til today I switched back to PLA for the moment. However, when printing ABS, I can't discover this kind of artifacts at all. Just for comparion, here's an ABS-printed part for my replacement alu bed:
And here is your test piece printed with PLA:
This makes me think your firmware is working properly, but perhaps the last layer of laid PLA doesn't cool down quickly enough and deforms when retraction is triggered. Out of curiosity, what do your extruder settings in Slic3r look like?
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Re: Printing artefacts: cause and remedy? April 20, 2014 03:05PM |
I *think* I know what's going on. Recently I've upgraded my Slic3r version to 1.0.0 stable and and since then I'm no longer able to print the XYZ testpiece because it messes up the Z-axis part by extruding too much filament into the solid infill. Now I'm using Slic3r 1.1.0 experimental and my testpiece seems to be printed properly - I'll report whether this has an effect on dc42's testpiece when I'm done calibrating 
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Re: Printing artefacts: cause and remedy? April 20, 2014 10:30PM |
A quick PS here as I need some sleep.
Look at the bottom of your print... There's lots to see....
Look at the infill...
If the lines of filament are thicker in one direction than the other, then your nozzel isn't vertical. It only has to be out a fraction.
When the first layer is printed we want the plastic to be pushed on to the glass. If the nozzle isn't vertical, you can have a hell of a time getting it to stick to the glass......
If the nozzle isn't vertical, in one direction it will be great, and pushed onto the glass ...Fairly thick... in the other direction thinner as it's rolling off the nozzle instead of getting pushed on to the glass, because it's round. Hence I designed new mounts....
This will also give you some of the artifacts your seeing in the sides, as it's doing a similar thing there...
(ie extruding some plastic to the side instead of downwards,...
But I think we will find out later that cooling is your main issue there... or should I say lack of cooling...
I'll run your stl later to find out.
You can tell allot from the bottom of the print... I don't run compensation, I hate it. I use a level bed...
When I look at the bottom of a print I can tell by the thickness of the filament lines if the bed needs leveling again.
(Mine gets knocked out by vibration of the ships engines when the vibration is extream).
If the bed moves out of level to far, the print won't stick to the glass, and a corner might lift, but you can tell by the thickness of the lines if it's a chilled air issue (BackWash), or a bed out of level issue... Thick lines are good, thin lines is where the bed is to low...
Thick lines with warping, are caused by BackWash chilling the print.... Which is where Big Blue steps in....
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
Look at the bottom of your print... There's lots to see....
Look at the infill...
If the lines of filament are thicker in one direction than the other, then your nozzel isn't vertical. It only has to be out a fraction.
When the first layer is printed we want the plastic to be pushed on to the glass. If the nozzle isn't vertical, you can have a hell of a time getting it to stick to the glass......
If the nozzle isn't vertical, in one direction it will be great, and pushed onto the glass ...Fairly thick... in the other direction thinner as it's rolling off the nozzle instead of getting pushed on to the glass, because it's round. Hence I designed new mounts....
This will also give you some of the artifacts your seeing in the sides, as it's doing a similar thing there...
(ie extruding some plastic to the side instead of downwards,...
But I think we will find out later that cooling is your main issue there... or should I say lack of cooling...
I'll run your stl later to find out.
You can tell allot from the bottom of the print... I don't run compensation, I hate it. I use a level bed...
When I look at the bottom of a print I can tell by the thickness of the filament lines if the bed needs leveling again.
(Mine gets knocked out by vibration of the ships engines when the vibration is extream).
If the bed moves out of level to far, the print won't stick to the glass, and a corner might lift, but you can tell by the thickness of the lines if it's a chilled air issue (BackWash), or a bed out of level issue... Thick lines are good, thin lines is where the bed is to low...
Thick lines with warping, are caused by BackWash chilling the print.... Which is where Big Blue steps in....
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
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Re: Printing artefacts: cause and remedy? April 20, 2014 11:47PM |
I'll try 175' later.... These look a bit hot
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
|
Re: Printing artefacts: cause and remedy? April 21, 2014 05:30AM |
BTW I meant to say that this Blue Filament I have here is a real pain.....
Ok I'll try and tweak the Slic3r settings some more later but here goes.
Now you will see there is some curling of the Brim.
1) I hadn't washed the glass and this spool of filament hates that....
2) I tried upping the amount of filament it layed down on the first layer, which it didn't like...
3) I'd dropped the bed temp a little to far.
But.... the actual print is better... The artifacts near the opening are about 1/3rd the size of the first print...
Mainly because I turned wipe on retract on.
Right I must get on with other stuff... I'll tweak again later.
Slic3r settings attached...
Edited 1 time(s). Last edit at 04/21/2014 05:45AM by KimBrown.
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
Ok I'll try and tweak the Slic3r settings some more later but here goes.
Now you will see there is some curling of the Brim.
1) I hadn't washed the glass and this spool of filament hates that....
2) I tried upping the amount of filament it layed down on the first layer, which it didn't like...
3) I'd dropped the bed temp a little to far.
But.... the actual print is better... The artifacts near the opening are about 1/3rd the size of the first print...
Mainly because I turned wipe on retract on.
Right I must get on with other stuff... I'll tweak again later.
Slic3r settings attached...
Edited 1 time(s). Last edit at 04/21/2014 05:45AM by KimBrown.
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
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Re: Printing artefacts: cause and remedy? April 21, 2014 07:48AM |
Yes I have DC42s settings he sent me ages ago for Slic3r which I might have to go back to.
The print was about 3/4hr in, it dropped a couple of loops which was odd, then 10 minutes later just built a platform across the whole print blocking everything off.....
Edited 1 time(s). Last edit at 04/21/2014 07:49AM by KimBrown.
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
The print was about 3/4hr in, it dropped a couple of loops which was odd, then 10 minutes later just built a platform across the whole print blocking everything off.....
Edited 1 time(s). Last edit at 04/21/2014 07:49AM by KimBrown.
Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete
|
Re: Printing artefacts: cause and remedy? April 22, 2014 12:31PM |
I think at least some of it is caused by the change of starting points after layer shift when the print gets to the hole, if so, adjusting the filament retraction should make a difference
Erik
Erik
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Re: Printing artefacts: cause and remedy? April 24, 2014 09:35AM |
Hi DC42,
Sliced with Slicr verrion 1.0.0.CR2:
When I look at your pictures, my first impression was:
Or you print directly from Pronterface in stead of the SD card (I strongly doubt it but I justy mention it to rule out this option
)
Or, the feederate of the extruder is too high
Or extruder temperature is too high (but even then the effect would not be so big)
But an other option could be the setting of the perimeters
What are your following settings:
Layer height (in my case 0.25mm)
Extruder width for perimeters? (default 0, in my case 0.75)
External perimiter first? (in my case no)
This last setting helped me to solve a sortlike issue where small droplets were seen on the outside of vertical surfaces. After unchecking External perimeters first, the droplets were gone so maybe that’s helpful.
Hope for you this is helpfull
Sliced with Slicr verrion 1.0.0.CR2:
When I look at your pictures, my first impression was:
Or you print directly from Pronterface in stead of the SD card (I strongly doubt it but I justy mention it to rule out this option
)Or, the feederate of the extruder is too high
Or extruder temperature is too high (but even then the effect would not be so big)
But an other option could be the setting of the perimeters
What are your following settings:
Layer height (in my case 0.25mm)
Extruder width for perimeters? (default 0, in my case 0.75)
External perimiter first? (in my case no)
This last setting helped me to solve a sortlike issue where small droplets were seen on the outside of vertical surfaces. After unchecking External perimeters first, the droplets were gone so maybe that’s helpful.
Hope for you this is helpfull
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Re: Printing artefacts: cause and remedy? April 24, 2014 10:48AM |
Two extra photo's of another test.
On the left outer perimiter first, on the right inner perimiter first
On the left outer perimiter first, on the right inner perimiter first
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