cut2cut
Posts: 3
Joined: Thu Jan 02, 2020 5:42 pm

how do I fix this print anomoly ?

Tue Jul 21, 2020 1:23 am

Looking for a bit of help. I have never seen this behavior before, please see the picture. At the thinnest part of the print ( due to the hole ) this print the layer characteristics change. ( 100% infill ) Note, this is CarbonX carbon fiber "infused" Ultem on a high temp printer ( 385 degree extruder , 125 degree bed and 70 degree chamber ). If anyone has any ideas as to why, I'm all ears !

Cheers,

Jake
Attachments
Screen Shot 2020-07-20 at 10.16.17 PM.jpg

gwhite
Posts: 138
Joined: Wed Jul 19, 2017 9:37 am

Re: how do I fix this print anomoly ?

Tue Jul 21, 2020 11:51 am

This happens quite a lot... Something in the model changes (externally or internally), and that forces the extrusion process to shift in some fashion. If you have the start location optimized for speed, the starting point will move around as the model changes, and the "seam" where it starts and stops will shift. One thing that can help is to tell it to always start a layer close to a specific XY location (like an edge).

cut2cut
Posts: 3
Joined: Thu Jan 02, 2020 5:42 pm

Re: how do I fix this print anomoly ?

Wed Jul 22, 2020 1:04 am

gwhite wrote:
Tue Jul 21, 2020 11:51 am
This happens quite a lot... Something in the model changes (externally or internally), and that forces the extrusion process to shift in some fashion. If you have the start location optimized for speed, the starting point will move around as the model changes, and the "seam" where it starts and stops will shift. One thing that can help is to tell it to always start a layer close to a specific XY location (like an edge).
Oh, I see the setting. Thank you. I'll experiment with that. It seems it will only work if I'm printing one thing at a time which is quite limiting.

Cheers,

Jake

airscapes
Posts: 334
Joined: Tue Mar 06, 2018 10:35 am
Location: Philadelphia PA Area

Re: how do I fix this print anomoly ?

Wed Jul 22, 2020 10:23 am

you can position each part so the place you want the layer change is closes to the point you chose, or create a process for each item with a different location that matches the part.

Daniel
Posts: 7
Joined: Thu Jan 17, 2019 9:04 pm

Re: how do I fix this print anomoly ?

Thu Jul 23, 2020 9:33 am

hi Jake
your picture show a darker and maybe a glossy finish in this zone
looks like it's print at lower speed in this zone so the filament had more time to heat and maybe less pressure in nozzle due to lots of retraction feature
if you look at your print speed in the gcode preview, this zone is probably darker blue than the rest of the part, if so your speed override is active

your part seem to be small if i compare the layers to the overall dimensions, that mean small print each side of the hole and less time to cool down
you said that you print multiple parts at the same time, so you have more retraction feature in this zone and more displacement too and by the way less nozzle pressure

maybe a different process in this zone with a lower nozzle temp can help you
or maybe just turning off speed override in this zone can help
but this is only suggestion, i didn't take time to experiment a lot in these kind of situations

good luck

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