Consistently skipping during last layer
 
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eileen.b
(@eileen-b)
New Member
Consistently skipping during last layer

Printing cookie cutters and on the last section of the build it is skipping at certain points of the build. It has done so in the same exact spaces 3 times in a row. I went back into fusion360 and saved 2 new files. One the handle of the cutter only, which printed fine. The other was just the last layer, the cutter of the cookie cutter, which printed defective with the same missing parts as in the print of the full cutter (pictures attached) The cutter layer is 2mm higher than the next and supposed to be .6mm thick. I'm not sure if this is a printer problem or a software problem. All previews of the cookie cutter in fusion360 and Slic3r for Prusa show no defects.

Posted : 14/07/2018 1:20 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Consistently skipping during last layer

Hi Eileen,
can you ZIP the STL and attach a copy for us to try?

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 14/07/2018 1:31 am
eileen.b
(@eileen-b)
New Member
Topic starter answered:
Re: Consistently skipping during last layer

I've attached the SVG and the gcodes also.

Posted : 14/07/2018 3:31 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Consistently skipping during last layer

Hi Eileen

I am having difficulty understanding what you are showing me...

the cutter only g code file seems to just have two prongs in it.
the other G code file seems to have a cookie cutter with a holding flange at the bottom, and two prongs at the top

if the prongs weren't there I expect the file would print...

how did you generate the G code?
I suspect you had a surface tessalation file (STL) which you loaded in to Slic3r

is there any chance of sending that STL file? in an attachment?
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 14/07/2018 4:04 am
eileen.b
(@eileen-b)
New Member
Topic starter answered:
Re: Consistently skipping during last layer

My apologies Joan, I sent the SVG instead. I've attached the STL, it was made in Fusion 360. I got the gcode from Slic3r Prusa Edition.

Posted : 14/07/2018 8:34 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Consistently skipping during last layer

Hi Eileen

your model is designed with some very thin sections at the cutting edge and the shoulders between the bat's cheeks and it's wings

additionally you have scaled the model down, so the thin parts get even thinner 🙁

so the Slicer doesn't place any filament where the section is too thin.

in the top picture, you can see two spikes

these are caused because the two lines come together in the pointed areas circled in the second picture.
[attachment=2]20180714_121353[1].jpg[/attachment]
in the third picture you can just about see the two spikes in reality. where I test printed the model...

it's not the best print, I set it going, using the dregs of a reel of filament at 200% speed, to print quickly, then forgot to slow it down for the top part... but it clearly shows that the thin edge section and the shoulder parts didn't get realised because they are too thin

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 14/07/2018 1:45 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Consistently skipping during last layer

Hi Eileen,

I trimmed the thin edge off the model, and extended the thicker part to the same height as the original, re scaled and re sliced the model and as you see it came out good.

[attachment=1]20180714_142319[1].jpg[/attachment]
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 14/07/2018 3:29 pm
eileen.b
(@eileen-b)
New Member
Topic starter answered:
Re: Consistently skipping during last layer

Hi Joan,
Your last few replies have greatly helped! I reconfigured my measurements in the designing process and i was able to print a cookie cutter successfully!! My problem has been solved! Thank you very much for your help. My only lasting question is that if i have a .4mm nozzle should i be able to print something that is .4mm and the same with a .25mm nozzle?

Posted : 23/07/2018 6:54 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Consistently skipping during last layer


My only lasting question is that if i have a .4mm nozzle should i be able to print something that is .4mm and the same with a .25mm nozzle?

In theory, yes but in practice, you will very often find that such "thin walls" are very weak and delaminate easily. Ideally you do need to print about 25% wider than the nozzle to get good layer adhesion on single-wall models.

You will also find that different slicers handle things differently.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 23/07/2018 9:49 am
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