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Retraction points - How good can it get?

Posted: Wed Apr 13, 2016 4:14 pm
by zemlin
I've been playing this game only since the end of January. Done a lot of printing and learned a lot of stuff, but I haven't done any intensive work on minimizing retraction zits. I've done some and am pretty happy with the results I get. FWIW, I normally set S3D to put all the retraction points along a line rather than scattered over the part - that way I limit my cleanup work to one area and the rest of the part looks splendid. :-)

My question for y'all is .... if I put in the effort, what's the best I can hope for as far as minimizing irregularities at retraction points? I'm assuming that because of the nature of the process they are simply a fact of life and will never go away completely. Can you share your best practices, settings, and photos for specific materials?

Re: Retraction points - How good can it get?

Posted: Wed Apr 13, 2016 4:30 pm
by sthone
I don't have any best setting to share but don't be afraid to play around with your Coast and Wipe setting either... those will help get rid of blobs and zits too.

Re: Retraction points - How good can it get?

Posted: Wed Apr 13, 2016 6:09 pm
by zemlin
sthone wrote:don't be afraid to play around with your Coast and Wipe setting either
Yep, I've played with all that stuff. Just trying to get some idea of where I should set the bar when trying to work things out. I also found that it is somewhat part dependent, in that a negative Extra Restart Distance worked great on one set of parts - then I tried something with a lot of small features and the plastic never made it out of the nozzle in some of the short bursts.

Re: Retraction points - How good can it get?

Posted: Thu Apr 14, 2016 12:31 pm
by willnewton
So you have already figured it out. There is no perfect setting, just the setting that works best for what you are printing right now. ;)

It sounds like you don't have a typical retraction issue, such as stringing between separate areas in the prints, just surface issues?

You asked us to post pictures and make suggestions, but what we need is a picture of YOUR prints and what you are trying to fix in them. My picture can't fix your issues. :)

Re: Retraction points - How good can it get?

Posted: Thu Apr 14, 2016 6:05 pm
by zemlin
I can post some pics in a couple days. I'm not mystified by the options in the software - they make sense. I can make improvements on things when I am having issues. The purpose of the post was to see your 'best of' builds from a quality standpoint so I can get a feel for the limits with different materials. I'm willing to put extra effort into getting a good build, but don't want to beat my head on the wall trying to achieve the impossible.

Re: Retraction points - How good can it get?

Posted: Thu Apr 14, 2016 7:04 pm
by Jules
zemlin wrote:I can post some pics in a couple days. I'm not mystified by the options in the software - they make sense. I can make improvements on things when I am having issues. The purpose of the post was to see your 'best of' builds from a quality standpoint so I can get a feel for the limits with different materials. I'm willing to put extra effort into getting a good build, but don't want to beat my head on the wall trying to achieve the impossible.
I can now, after a year, get perfect builds in PLA and PETG. Almost perfect builds in the wood filaments. Average builds in PVA. Sometimes the filament really does fight you and you can only achieve "pretty good, all things considered".
No globs, no zits, no gaps, no cracks, no warping, no stringing, no over-extruded lip on the first row, first layer same size as the others, even bottom pattern, water-fill flat top layer......is my definition of perfect. It can take months (and hundreds of calibration squares) to achieve perfection with a particular kind of filament, but it is doable. Just depends how much time you want to spend on it - the more you do, the better they'll get.

And the better you'll get at it - it definitely took longest to figure out what was going on with the first one. After that it gets a lot quicker. :D

Re: Retraction points - How good can it get?

Posted: Wed May 11, 2016 4:38 am
by forever9801
Jules wrote: I can now, after a year, get perfect builds in PLA and PETG. Almost perfect builds in the wood filaments. Average builds in PVA. Sometimes the filament really does fight you and you can only achieve "pretty good, all things considered". :D
How did you manage to stop PETG from dropping burnt filament that stuck on the nozzle into the printed parts from time to time? I can deal with the stringy with heated air blower, but it's the burnt doping that kept on getting into my nerve :oops:

Re: Retraction points - How good can it get?

Posted: Wed May 11, 2016 5:11 am
by Jules
forever9801 wrote:
Jules wrote: I can now, after a year, get perfect builds in PLA and PETG. Almost perfect builds in the wood filaments. Average builds in PVA. Sometimes the filament really does fight you and you can only achieve "pretty good, all things considered". :D
How did you manage to stop PETG from dropping burnt filament that stuck on the nozzle into the printed parts from time to time? I can deal with the stringy with heated air blower, but it's the burnt doping that kept on getting into my nerve :oops:
Very, very, very careful gap determination, and slight under-extrusion. The PETG needs to almost "air print" a little bit, because if it touches the layer below at all, the nozzle will pick up those superfine threads and those just get crisped on the nozzle and drop off later into the print. It's actually easier to control that on the older machines - the newer ones cannot be fine tuned as carefully. (yet.)