rmimoun
Posts: 5
Joined: Sun Aug 28, 2016 7:46 am

Re: Impossible to remove retraction defects with S3D

Tue Aug 29, 2017 6:45 pm

I stand corrected. To be clear, I eliminated the bumps quite fast, but there was always a vertical scar where the layer change happened. It was _very_ visible. For testing, I scetched a simple object, a tube with 20mm outer diameter, 18mm inner diameter and 5mm height. The layer change zone looked like these "volcanoes will be here one day" pictures in school books, en miniature.

While playing around with profiles I found on the internet, the scars vanished. Cool, but why? Simple, the layer change does not happen on a single place anymore. Means: The layer x stops eg. at 0° of the outer circle in that tube (I print inside-out to get a better surface, but that makes no real difference here). Layer x+1 starts at 15° of the inner circle. So, you have a really tiny bump at the outer layer and another one, in a distance, at the inner layer. So, you get two vertical lines, only one on each surface, that are almost invisible instead of one big ugly one.

In the end, it was the "Wipe Nozzle" parameter. In that configuration, it wipes the nozzle for about 4mm. It does not matter if you define the layer start next to a specific location or just for fastest speed. Which is a flaw in my view, because when the nozzle is at a specific location after the whipe, the fastest way would be to change to the next layer right there and not go back x mm to start there, but I am happy with that :) Oh, and you should switch off "Force retraction between layers".

studiodyne
Posts: 26
Joined: Wed Nov 26, 2014 12:59 pm

Re: Impossible to remove retraction defects with S3D

Wed Aug 30, 2017 7:20 am

Force retraction on layer change ?? no !
Because you stop the extrusion that runs , to make a retraction + a recover , not serious
The best printing is to retract/ recover only when needed , and always where it's impossible to be seen
To perimeters for example , we will use 2 permiters , just to start the ' recover ' inside the object and to have a perfect outline without stopping process
The position of the first start of the layer , will leave a default , then , we will place the starting in a face of the object that we will never be seen when done
And there is no ' recover ' that is perfect , and will always be seen , then , try to make 2 permiters with ' inside first ' , try to place the starting extrusion on the center of the model
I think , the other slicers are SMART and simplify3d is MANUALLY SMART loll
For me it's just the intelligence of the ' recover restart ' placement somewhere where it will be invisible
For your circular object placed in the center of the builplate , with 2 permiters ' inside first ' and 'starting extusion' at ' 0,0 ' , will never make a ' retractation process on the outlines '

Hope it serves to you

ishootyou
Posts: 1
Joined: Tue Nov 14, 2017 7:31 pm

Re: Impossible to remove retraction defects with S3D

Tue Nov 14, 2017 7:36 pm

rmimoun wrote:I stand corrected. To be clear, I eliminated the bumps quite fast, but there was always a vertical scar where the layer change happened. It was _very_ visible. For testing, I scetched a simple object, a tube with 20mm outer diameter, 18mm inner diameter and 5mm height. The layer change zone looked like these "volcanoes will be here one day" pictures in school books, en miniature.

While playing around with profiles I found on the internet, the scars vanished. Cool, but why? Simple, the layer change does not happen on a single place anymore. Means: The layer x stops eg. at 0° of the outer circle in that tube (I print inside-out to get a better surface, but that makes no real difference here). Layer x+1 starts at 15° of the inner circle. So, you have a really tiny bump at the outer layer and another one, in a distance, at the inner layer. So, you get two vertical lines, only one on each surface, that are almost invisible instead of one big ugly one.

In the end, it was the "Wipe Nozzle" parameter. In that configuration, it wipes the nozzle for about 4mm. It does not matter if you define the layer start next to a specific location or just for fastest speed. Which is a flaw in my view, because when the nozzle is at a specific location after the whipe, the fastest way would be to change to the next layer right there and not go back x mm to start there, but I am happy with that :) Oh, and you should switch off "Force retraction between layers".
Can you upload your profile anywhere and post the download link, pls? :D

nigeljh
Posts: 3
Joined: Sat Apr 25, 2015 4:58 am

Re: Impossible to remove retraction defects with S3D

Thu Jun 14, 2018 5:22 am

Came across this thread whilst suffering from the same artifacts on exterior surface of prints .. They showed up in the preview as well..

Machine is a Kossel XL with a bowden, so retraction set to 5mm etc for normal bowden operation ...

I turned off the 'coast at end' setting and they vanished in the preview .. However they still appear on the print, albeit much smaller!

Still have the wipe setting enabled , along with retract on open spaces and during wipe, and printing inside-out ...

airscapes
Posts: 195
Joined: Tue Mar 06, 2018 10:35 am
Location: Philadelphia PA Area

Re: Impossible to remove retraction defects with S3D

Thu Jun 14, 2018 12:55 pm

I just gave up and accept the fact this is FFF and not injection molding.. maybe the next release will be better.. for now, strong well bonded parts that don't break can have a line in them.. :shock:

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