Infill gaps and Parts to fit

Hello there, I have a issue calibrating the extrusion multiplier in slic3r. If its too high ~1 my parts don't fit together - i need around 0.6mm tolerance. But i've seen people on thingiverse getting flush parts to fit, and this is very annoying when downloading as a lot of them don't work of them because of this. On the other hand around 0.85 my solid infill has gaps between the single extrusions. I've been having this issue for ages. Any ideas what could be causing this/how to fix it? Thanks in advance

Calibrate your e-steps per mm first and make sure you have the correct filament diameter in your slicer settings. Measure the filament diameter with a set of calipers - don't believe what the manufacturer tells you.

Calibration guide on the reprap wiki.

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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.

There is no simple answer to your question and with the information you give us it is in no way possible to find any usefull answer.
You may try to read this thread below, but if you get to the end of it you will find that many questions are left open and give only a few anwers :
[forums.reprap.org]

Good luck

I calibrated filament diameter (measured in 5 different places and averaged)
I calibrated my e-step got around 807 on a gregs wade using RAMPs
If I set Extrusion multiplier in slicer to 1 i get a nice solid infill but my parts don't fit together nicely. Holes are too small and the outside is too big.
I followed this guide to calibrate my extrusion multiplier in slic3r and got 0.85
Now if I print my solid infills aren't solid they're made of unconnected extrusions.

People in the link you posted suspected in may be a bug in slic3r. Although it was half a year ago and I expect any such glich to be resolved by now, I will try kisslic3r and report back my results

There's long been a bug in Slic3r about inner hole diameters, I don't know about outer dimensions. I would try the commonly beloved Kisslicer, or even Cura. I use Simplify3D [$140] and have removed all previous issues related to slicing.
E-steps only control amount of plastic, but you X and Y steps control the size and distance, have you thoroughly calibrated those?

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

I tried using Cura. The issue is still there. It's not a issue with X/Y steps I measured the amount of movement and it was perfect. Problem with X/Y steps would make both holes and outer dimensions smaller or larger. For me the holes are too small and the outer dimensions too large. I have no idea what to do. Someone please help

Do you have the proper nozzle size and extrusion width calibrated?

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

I have entered the correct nozzle size 0.5mm (I have measured it to make sure it is as advertised). I tried calibrating the perimeter width using the guide on the wiki, but the problem persisted. I also believe slic3r takes into account the extrusion width so it shouldn't have an impact. Someone please correct me if I'm wrong, this is just what I noticed.

Here's all relevant settings in Slic3r 1.1.4 (same thing happens in all version I've tried as well as other slicers such as Cura with default settings):

First Layer Temp:230
Other layers:220
BedTemp: 100

Layer-height: 0.35 mm
Perimeters: 2
Default Extrusion Width: 150%
Perimeter Extrusion width: 120%
Extrusion Multiplier: 1 (parts don't fit even if I lower this to 0.85)

I've also calibrated E-steps using this guide and measured X/Y movement using digital calipers. Regardless I'll try printing with different X/Y steps and report back here. Any suggestions are appreciated.

Edited 1 time(s). Last edit at 06/13/2014 01:36PM by mikh3x4.

Quote
mikh3x4
I have entered the correct nozzle size 0.5mm (I have measured it to make sure it is as advertised). I tried calibrating the perimeter width using the guide on the wiki, but the problem persisted. I also believe slic3r takes into account the extrusion width so it shouldn't have an impact. Someone please correct me if I'm wrong, this is just what I noticed.

Here's all relevant settings in Slic3r 1.1.4 (same thing happens in all version I've tried as well as other slicers such as Cura with default settings):

First Layer Temp:230
Other layers:220
BedTemp: 100

Layer-height: 0.35 mm
Perimeters: 2
Default Extrusion Width: 150%
Perimeter Extrusion width: 120%
Extrusion Multiplier: 1 (parts don't fit even if I lower this to 0.85)

I've also calibrated E-steps using this guide and measured X/Y movement using digital calipers. Regardless I'll try printing with different X/Y steps and report back here. Any suggestions are appreciated.

Hi, did you manage to get it right? I have exactly the same problem. E steps calibrated (tested on 500mm of extrusion, extruder ate exactly 500mm of filament), X/Y are also all right. Parts to fit have to small holes and too big outside.

Could you show us a picture of some prints, showing infill on the top and also the layers on the sides? If there are shifts in the layers (like z wobble) or other errors will influence how parts fit together. I've got the tolerance down to 0.15mm on each side. So if I need to fit a square peg of 10mm into a matching hole, The hole needs to be 10.3mm for the part to fit easily. Blobs on layer changes and retractions can further prevent snugly fitting parts from fitting at all.
For small circular holes like 8mm to fit a smoothrod for example, I used an object with a hole of 8.34mm, which fits very well on the smoothrod without binding. Printed in nylon it works well as a bearing, it has less play than a LM8UU bearing.


Also be aware that things posted on thingiverse are often not checked, printed or even fit for slicing. The print instructions are often missing what the print settings should be, like extrusion width and layer height, what material to print it with etc.

You can try getting your printer print with better accuracy, eliminating extrusion aberrations, z-wobble, ringing/corner waves, over extrusion, backlash, blobbing, bridging etc.

Edited 1 time(s). Last edit at 11/23/2015 09:57AM by imqqmi.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Imqqmi, thanks for the response.
I'm attaching a photo of few test prints from today:
1. 20mm cube
2. 20mm empty cube, walls 0.4 (testing wall width)
3. Part fit test.

Edited 1 time(s). Last edit at 11/23/2015 05:15PM by Darmach.

My five cents when it comes to matching and fitting parts:
1. All the tweaking of print settings is useless if the printer is not properly calibrated, motor stepping can be a pain to get 100% correct.
2. The exrusion rates and line widths must be as close as possible to what is set in the settings.
In many cases it can be simple to get 10mm test cube to be perfect on the outside but holes...
3. Keep in mind the physics of 3D printing and tolerances as used in the techical and engineering world!
If you need a8mm rod to perfectly fit into a hole on a machine, then either the rod is less than 8mm or the hole is more than 8mm in diameter.
Sure you can have it the other way around for high temp press fittings but that is not the point here.
If you print a 0.5mm line with good calibration than it will be a 0.5mm, but it won't be 0.5mm where the line changes direction and a circle is just many straight lines with directional changes.
On the outside of the changes there might be less plastic but usually on the inside there is always more plastic than required.
Some of this can be compensated for by using very fast jerk and acceleration settings - but this often comes at the price of accuracy as it can cause vibrations and missing steps.


How to measure to excess extrusion for inside holes:
Print box 20x20mm with 1mm thick walls.
The inside should measure 18x18mm - if that is the case good so far.
Now measure across from one inside corner to the opposite corner.
In a perfect world it should measure 25.46mm but you will be shorter.
Whatever amount is more here is you absolute printing tolerance margin.
If it is around 26mm it is quite good, 27mm is really bad, getting under 26mm and still keeping all extrusion good including layer bonding and you are close to perfect.
Of course you still have to take care of little blobs or wobbles by cutting and sanding.

One object I quite like for these test is this thing.
In the customizer you can set the tolerances and make it smaller if you want.
With PLA I can go down to 0.15mm before it gets really hard to make the gear move, with this you can also see if your first layer is correct as otherwise the gears will bind there already.
0.2mm seems to be a good value that still keeps everything moving without too much wobble while it is still easy to break the little bonds to make it moove smoothly.
Abs gives me the limit at 0.2mm but I have not done a test with the new craft glue. Last test still showed some minor warping, so 0.15mm could be possible here too.
Nylon is a pain in ... for those jobs.
I managed to get down to 0.25mm tolerance but had a really hard time to free the gears.
Once free and after a round in the cordless drill it was a smooth rolling motion with very little play.
Problem with nylon is the extreme expansion and shrinking during the print.

It looks a bit overextruded but otherwise print quality seems good. The single wall test seems problematic. What are the slicer settings? Is the automatic volume or pressure contrpl turned on? What retraction settings do you use? Is there any extra extrusion set after unretracting?

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Quote
imqqmi
It looks a bit overextruded but otherwise print quality seems good. The single wall test seems problematic. What are the slicer settings? Is the automatic volume or pressure contrpl turned on? What retraction settings do you use? Is there any extra extrusion set after unretracting?

From slicer:
nozzle diameter 0.3
0.2 layer
perimeters-shells: 3-3-3
Infill 20%
speed 30mm/s for perimeters
infill 60
top solid infill 50
default extrusion width set to 0.3, rest 0 (auto) except first layer 200%
automatic volume or pressure control - not even sure where can I find that, I didnt turn it on for sure .)
retraction: 1 mm, 30mm/s, no extra length on restart, retract on layer change

Try an extrusion width of 0.4. Filament has the tendency to expand when leaving the nozzle. The rule of thumb is about 1.25 x nozzle diameter for extrusion width. Is it a bowden setup?

Calibrate the extruder multiplier like in this video:
calibrate extrusion

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Sorry for the confusion, checked the actual gcode, and I was printing that at 0.4 - this was set to auto back then, and with 0.3 nozzle slic3r set it to 0.4.
Thats a wade with 9/49 ratio.
I'll take a look on this video, and get back here with some test tomorrow .)
Thanks!

Hi,

Im attaching the picture of another test, sliced with 0.3 extrusion.
The holes/plugs dimensions are wrong as usual, the big angle is a little bit too small - but I think thats because of abs thermal shrinkage being bigger than my issue error.




The second image shows the object before (on the right) and after the calibration according to the youtube link from the post above.
Result is very weird - earlier I did already calibrate my extrusion by calculating the value first, then extruding some amount (measured filament not extrusion) and correcting calculated error.
Finally I did test it on 500mm filament, and extruder ate 499,80 or something like that. I thought that was the perfect result.

However - calibration according to instructions from the video imqqmi posted tells I have a huge misconfiguration! In the video they got .96 coefficient, while my calculated was... ...0.69! 2/3rd, thats a lot to correct.
The object on the left on second picture was printed with 0.69 extrusion multiplier. Walls are 0.3, so its right as it should be - except of the part where the old layer ends, and new extrusion starts. It does seem like the old layer gets narrow near the end, and new one is too thick in the beginning (0.4+ vs 0.3).

Two questions arose:
1. Is it possible that I should use 0.69 extrusion multiplier? This doesnt seem right.
2. That wall getting more narrow near the end, and too thick in the beginning of a new layer - something wrong with retraction? retracts too much on layer change?

P.S. Right now Im printing that "test set" from first ficture, with 0.69 extrusion multiplier as calibrated on the second picture. I wonder how will it go.

Edited 1 time(s). Last edit at 11/27/2015 04:33AM by Darmach.

Well, it completed...



Result is messy, underextruded a lot. Very fragile, layers nod adhering at all (actually funny, they break with slight touch).
Maybe because Slic3r choose 0.3 extrusion width when set to auto?



...but the plugs fit well.

I will repeat that test with 0.4 extrusion width.

I disagree with your assessment, your extrusion is pretty close to perfect. What over exrusion has covered up is a good degree of backlash. Please see my blog about backlash. Once that is solved you're well on your way for quality prints. Slic3rs automatic extrusion width often choses the wrong width, just set it between 0.4 and 0.5 for a .3mm nozzle. If you design your parts with the metric system 0.5mm width can be very pracical.

The cross section of the extruded filament should take the shape of a flattened bead. If you set layer height = extrusion width the bead is more like a circle, and has a very small area touching each layer. The rule of thumb is extrusion width should at least be 1.25 x nozzle diameter and layer height at maximum 0.8 x nozzle diameter. The lower the layer height the wider/flatter the bead, the higher the pressure pushing the new layer on the previous the stronger the layer adhesion.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Hi imqqmi,
Well, I have gaps on 100% infill - for example on top layers. This is not a proper behaviour, right?
And layers are not adhering together almost at all - I can break these objects with two fingers .)

Gaps - take a look at these:


Could you post the link to your backlash post?
EDIT: Ok, I found it.
You write about pairing lines - I dont have any such on these prints. Not at all.
Its hard to show without good macro lenses (and Im doing photos with my phone) but the lines are nicely, and evenly spread. They just dont touch each other.

The whole frame is constructed from 30x30 heavy aluminum extrusions, very rigid, witm 50x50 90 degree angle joints. Of cource GT2 belt can introduce some play, but its also set very tense.
Parts itself are either aluminum (water cut) or SLS printer polyamide.

EDIT: I managed to get a better picture:


EDIT: Aaand another edit, @imqqmi - talking about backlash, what do you think about this part as a test? [www.thingiverse.com] I will print - just to be sure ,)

Edited 5 time(s). Last edit at 11/27/2015 09:32AM by Darmach.

Ok, thought i could see some pairing, but it's not much. I've seen the perimeter gaps before in slic3r. What settings were used, extrusion with and layer height, speed? What temperature? I assume it's pla? the corners look rounded and uneven, seems like it's pulling the filament in, cutting corners. I'm still not convinced it's just underextrusion. If you bump up extrusion parts will not fit and top infill will be overextruded. But try increasing it by 5%.
It also looks as though the temperature is too low, could you try increasing it by 5-10 degrees? How many solid top layers is it set to?
could you link me to the calibration parts and post the gcode you used? Someyimes you can see there's gaps in the repeyier preview. By changing the extrusion width manually can help sometimes.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Extrusion width: 0.4
Layer height: 0.2
Perimeter speed: 30 mm/s
External perimeter: 70%
Infill: 60 mm/s
Solid infill: 60 mm/s
Top solid infill: 50 mm/s
Travel: 130 mm/s

Its ABS, manufacturer suggested temp is 242 celcius / 110 HB. I found that around 240-243 it produces the strongest prints, bed 110 with ABS juice - can go lower.

I have to go out now, but tomorrow I will try to bump up extrusion multiplier by 5% and print few iterations, each 5% more.

Thank you for all the help .)

I print ABS at 268 degrees C, I use a thermo couple, I can be pretty sure it's really on that temperature. I'd try to increase the temperature some more, it should also improve adhesion.

Glad to help, let me know how the latest tests go

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Hello .)

I tested same print today - this time starting with 0.9 multiplier, so just a little bit lowering the default extrusion.

I got prints with almost, but barely fitting plugs - but startin to show gaps between the lines. I find all of that weird, I get nice finish with not bad top at 0.95 extrusion - so 1.0 looks like its a little bit over extruded. But plugs start to fit lower than 0.88 - and at that moment gaps between the lines are starting to appear on top layers, and parts lose mechanical strength....

I tested also today for backlash. As I dont seem to be able to slice lashmaze with slic3r - tested 3 versions including newest, it claims it finds multiple errors in the model (redownloaded from different sources few times) - I used that test: [www.thingiverse.com]

What do you think about it? What value of backlash is acceptable?

EDIT: Actually forgot, wanted to ask you one more thing - how tense should my GT2 belt be? Maybe belt loosenes is one of the reasons for my fitting issue. Here is how tense is my belt right now, is it too lose?
[www.youtube.com]

Edited 1 time(s). Last edit at 11/28/2015 02:51PM by Darmach.

Guys, is it possible that I have wrong nozzle size set? I bought my nozzle from Chinese, maybe its not at all 0.3 mm?

Would it have such impact on the prints?