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Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Sun Sep 10, 2017 1:01 pm
by swatti
I'm printing a "plate" so to speak with quite some size to it. It has lots of 3mm screw-holes in it.

For reasons unkown the machine stops after each loop and just oozes in place for like half-a-second. To prevent this, i have to use up to 10mm coasting settings. This simply REMOVES all small screw-holes and the print goes bad.

Why does it stop there before it begins the next loop?

Small parts are nearly impossible to print because infills are simply removed by the coasting. Without the coasting corners have massive blobs on em. If i reduce extrusion, all the open areas are left under-extruded.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Thu Sep 14, 2017 3:28 am
by horst.w
No answers for 4 days for such a simple question???

May caused by the missing FACTORY-FILE!

Regards
horst.w, GER

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Wed Sep 20, 2017 6:14 am
by swatti
I'l post the FFF-file as i get back home but i doubt that helps much... Its merely "default" settings with greatly increased speed and thus comes the need for coasting.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Wed Sep 20, 2017 6:22 am
by dkightley
I'l post the FFF-file as i get back home but i doubt that helps much
You were requested to post the factory file.....not the profile. And the factory file WILL be helpful despite your doubts!...that is provided you really do want some help.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Sun Sep 24, 2017 1:30 am
by swatti
Ookkey...

Heres the file, well, one of many.

Speed reduced a lot. I run this at 100+ mm/s, or should be running it at that. Cant, makes it blobby. Takes 5 hours+ now, me no likey.
I usually just print it at 0.33 height. In this file im testing to print it lower height where the curves are.

Blobs appear always at the end of each loop.

The part is for an airsoft aplication. A part of a magazine that feeds from 2 sources. The BBs go thru the y-part and merge into one feed. This needs quite some accuracy to work properly.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Sun Sep 24, 2017 12:17 pm
by gearsawe
Coasting is usually a small value. It tells the extruder to stop extruding material in your case a while 10mm before the end of a of loop. If a loop does use 10mm of material it would extrude nothing. Personally I have not found coasting that useful yet. It may fix one small problem in a print but cause to many others.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Sun Sep 24, 2017 1:51 pm
by swatti
If i HALF my coasting, the blobs will pile up so high my prints crack off the bed.

Coasting is not the "problem"
Coasting is good, embrace it!

Why is my machine generating a massive pressure in the nozzle? EVEN if i drop speeds to stupidly slow, it still happens.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Sun Sep 24, 2017 3:02 pm
by MasterFX
10mm Retraction seems a little bit too much, even for bowden.
Maybe you shold try this the following settings and post images of your print:

Retraction Distance: 6-8mm
Extra Restart: 0mm
Vertical lift: 0.2mm (maybe you should use a lower layer height, 0.33mm is almost the limit for 0.4mm nozzle and use multiples of your hardware full step resolution, most printers have 0.04mm/fullstep)
Retraction Speed: 60-90mm/s
Coast at end: 0.2mm
Wipe => Disable

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Mon Sep 25, 2017 8:50 am
by swatti
Got desparate and dismantled my entire bowden setup.

9mm retract. No strings with this.
ret-speed at 40mm/s. Could go higher...
Wiping: off
Extra restart at 0.2mm
Lift at 1mm. Works.
Coasting at 3.60mm

Seems to be LOT less blobbing and im only printing at 110mm/s so theres room to go past the 150mm/s mark. I print big with high acc/jerk so i dare say it does run the speeds.

My smoothie mobo dropped in the mail so i think this topic wont have much purpose soon...

I'l be returning to bowden when i get my tilting Y-head dual running.

Re: Long "coasting" removes loops. No coasting -> blobs/ooze

Posted: Thu Sep 28, 2017 11:50 am
by jfkansas
That profile is so out of whack I'm not sure where to begin. 10mm of retraction takes time, it doesn't happen instantly. For every 10mm of retraction you also have to wait for 10mm + 1mm of prime.

Printing fast increases nozzle pressure, and the faster you print the more pressure.

I don't see a lot of reason to do 3 processes for that part either.

The other poster was right, .24 mm for the whole thing should be fine. Anything over .3 with a .4 nozzle is approaching the limits of the of that size nozzle.

swatti wrote:Ookkey...

Heres the file, well, one of many.

Speed reduced a lot. I run this at 100+ mm/s, or should be running it at that. Cant, makes it blobby. Takes 5 hours+ now, me no likey.
I usually just print it at 0.33 height. In this file im testing to print it lower height where the curves are.

Blobs appear always at the end of each loop.

The part is for an airsoft aplication. A part of a magazine that feeds from 2 sources. The BBs go thru the y-part and merge into one feed. This needs quite some accuracy to work properly.