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Variable Intra-Layer Speeds To Improve Print Quality

Posted: 19 Jun 2016, 15:39
by inventabuild
Jonathan,

Can you develop variable intra-layer speeds that depend on the degree of overhang? What follows are three pictures that show how slowing down the print speed on overhangs up to 57 degrees can create nice smooth surface finishes without the need for support. In fact adding support to the slowest speed print of these examples appears to make the surface finish worse, not better. I have not experimented w/ overhangs > 57 degrees yet so I don't know if there is an overhang degree limit where support will give a better finish vs no support at slow speeds:

At perimeter print speed 30 and overhang 57 degress the surface finish over a large area is rough and wavy (area circled in red):
Perimeter Print Speed 30 - No Support
Perimeter Print Speed 30 - No Support
KISS Perimeter Print Speed 30 - No Support - Markup.jpg (44.43 KiB) Viewed 4505 times
At perimeter print speed 15 and overhang 57 degress the area with a rough, wavy surface finish (circled in red) is smaller than at perimeter print speed 30:
Perimeter Print Speed 15 - No Support
Perimeter Print Speed 15 - No Support
Perimeter Print Speed 15 - No Support - Markup.jpg (41.58 KiB) Viewed 4505 times
At perimeter print speed 5 and overhang 57 degress the surface finish is relatively smooth with only minor surface blemish over a small area of the overhang:
Perimeter Print Speed 5 - No Suport
Perimeter Print Speed 5 - No Suport
Perimeter Print Speed 5 - No Support.jpg (39.01 KiB) Viewed 4505 times
Printing w/out support and all print moves at speed 30 mm / sec the whole print takes 5 hours 24 minutes.
Printing w/ support and all print moves at speed 30 mm / sec the whole print takes 6 hours 29 minutes; however printing w/ support still gave a rough surface finish.
Printing w/out support and printing the perimeter at 5 mm / sec and loops at 15 mm / sec gave me a nice surface finish w/ only minor blemish, but the print took 9 hours 1 minute. If you could create a variable layer speed that for example would print at 30 mm on the non-overhang section of the layer and slow down a % based on the degree of overhang it encounters, that would greatly reduce print time and at the same time help give an awesome surface finish on prints w/ overhangs.

Something like variable intra-layer speeds might also come in handy for the Coast feature you are looking at creating.

Edit: Perhaps in the first step towards implementation you could have two sets of print speeds. One set of print speeds for layers where the overhang is < than the support threshold (in the Support tab) and a second set of print speeds for when the layer contains an overhang(s) >= the support threshold. That way at least layers that have minimum overhangs can be set to print faster and layers with larger overhangs (for example > 45 degrees) can be set to print appropriately slow to improve the overhang area print quality.

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 22 Jun 2016, 18:10
by inventabuild
Update: Running perimeter print speed 2.4 mm / sec, loops at 6.6 mm / sec and infill 30 mm / sec I get a perfectly smooth print on the 57 degree overhang of the frog belly just as good as the print on the top of the frog. The path lines you see are only reflections from the light I used to take the picture and they show in both the bottom of the frog where the 57 degree overhang occurs as well as the top of the frog where there is no overhang.
Smooth Print on 57 Degree Overhang of Frog Belly.  Printed at 2.4 mm / sec Perimeter
Smooth Print on 57 Degree Overhang of Frog Belly. Printed at 2.4 mm / sec Perimeter
Perimeter Print Speed 2.4 - No Support.jpg (36.9 KiB) Viewed 4476 times
Smooth Print on Top of Frog.  Printed at 2.4 mm / sec Perimeter
Smooth Print on Top of Frog. Printed at 2.4 mm / sec Perimeter
Perimeter Print Speed 2.4 - Top of Frog.jpg (77.62 KiB) Viewed 4476 times
Jonathan does modifying print speed based on the degree of overhang seem like a good idea?

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 23 Jun 2016, 04:55
by MorganTH
I like a lot this idea.
I was thinking of somethink like it, for specific parts you ll be able to setup for layer X to layer Y different setting speed. Somethink like the N[*] Layer but with two values. But the printing speed which depend on the overhang can be a really really nice idea.
I ll follow this request with a lot of interest !

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 25 Jun 2016, 13:42
by lonesock
I like the idea! I will think on it some more once the 1.5 release is out. Thanks for doing the research!

Jonathan

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 24 Aug 2016, 18:37
by neel
+1

Just suggested something similar before I see your post:
viewtopic.php?f=13&t=1364

Also this other suggestion to display layer time may help too, it is related to this same subject in fact:
viewtopic.php?f=13&t=1365

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 03 Jan 2017, 17:59
by Bubolz
Variable speed for small perimeters and overhangs is just what I need to get really perfect prints ;)

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 04 Jan 2017, 19:15
by Doug
Great Idea
I'm looking forward to seeing it implemented

Re: Variable Intra-Layer Speeds To Improve Print Quality

Posted: 06 Aug 2019, 03:39
by chrish_92
Any news on this feature request? As far as I can see it has not been implemented yet, right?
I would really really love this feature, I think it greatly enhances the print quality of a lot of printed parts.