wirlybird
Posts: 1142
Joined: Sun Jul 17, 2016 1:32 pm

How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:06 pm

I have a large print with a lot of details and small areas that are internal to the part.
The extruder travels over this area and can cause damage to the more delicate sections.

Is there a way to keep the extruder from crossing over this area or have it avoid the internal parts when making travel moves?

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dkightley
Posts: 1995
Joined: Tue Mar 10, 2015 4:09 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:15 pm

Isn't Retraction vertical Lift designed to avoid the nozzle scraping across the surface of the extruded part??
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

wirlybird
Posts: 1142
Joined: Sun Jul 17, 2016 1:32 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:18 pm

Yes and may be my only recourse.
I just thought it didn't work so well on machines where the build platform moved in the Z.

Never really used it other than on my Prusa machines.

JWest
Posts: 14
Joined: Fri May 06, 2016 5:36 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:20 pm

You can use nozzle lift but the question should also be why it is happening. Over extrusion can often cause scarring as the extruded plastic fans out in all directions making it thicker than the layer height expected by the slicer. This can be an accumalative effect.

TheBum
Posts: 76
Joined: Fri May 18, 2018 11:13 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:29 pm

Have you tried experimenting with the Avoid Crossing Outlines for Travel Movements setting in the Advanced tab of the profile?

wirlybird
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Joined: Sun Jul 17, 2016 1:32 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:32 pm

What is happening is I have these areas inside the print. The top edges of each little rectangle start to curl a slight bit when they reach their final couple layers which is unavoidable.

This printers travel moves are extremely fast (350mm/s x/y) and set by the maker in their S3D profile.

The nozzle grates across the tops at high speed and is catching the edges and breaking them off.

My two other machines I use move much slower for travel and you can hear the nozzle hitting but it never breaks them off.

My other machines use an MK10 nozzle which has a much smaller tip area than the nozzle on this volcano hot end even though they are all 0.4mm.

Going to try the hop as is being suggested by the maker.
2.png

wirlybird
Posts: 1142
Joined: Sun Jul 17, 2016 1:32 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:33 pm

TheBum wrote:
Mon Jun 10, 2019 7:29 pm
Have you tried experimenting with the Avoid Crossing Outlines for Travel Movements setting in the Advanced tab of the profile?
I thought of that and set it but it looks like in the preview that it is still crossing it.

Maybe it takes a really high number to get it to stick to the perimeters which would be ideal.

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dkightley
Posts: 1995
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Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:40 pm

The Avoid Crossing Outline feature is not appropriate for the model as per your screenshot. The "outline" is being crossed on every move!

Avoid Crossing Outline is useful for objects that for example are horseshoe shaped....where a path from one point of the horseshoe to the other end of the horseshoe can be diverted to follow the shape....rather than zipping across open space!

Retraction Vertical Lift is going to be the option to go for. Messing with flow, etc may not yield desired results....particularly with a Bowden printer!
Last edited by dkightley on Mon Jun 10, 2019 7:44 pm, edited 1 time in total.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

wirlybird
Posts: 1142
Joined: Sun Jul 17, 2016 1:32 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Mon Jun 10, 2019 7:43 pm

Thanks Doug, that is what I thought. I do use it on another part to keep the extruder travel within the boundaries of the part. Works well there.

TheBum
Posts: 76
Joined: Fri May 18, 2018 11:13 pm

Re: How To Avoid Extruder Travel over Internal Area Of Print

Tue Jun 11, 2019 11:47 am

I find on my PETG prints that I have to set the option to retract on every move in addition to vertical lift or else I get horrible stringing. It's in the Ooze Control settings. This also helps with not getting artifacts across surfaces as the nozzle passes. It considerably slows the printing process, but I'd rather have clean prints and running overnight is not an issue.

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