For the most part, I’m getting acceptable prints for what I need. The only thing that ‘annoys’ me are the occasional boogers I get. Right now I’m playing with the retraction settings via http://retractioncalibration.com/ For some filaments I’m getting ‘decent’ prints, for others I’m still getting boogers even at retraction distances of 5mm and speeds as LOW as 5mm/s (default is 60mm/s??). My latest try is not showing boogers but the walls have, in some places, significant holes. This one is with Snapmaker PLA at 200C, retraction distance, 5mm all around, retraction speed from 10 (bottom) to 20 (top) mm/s. The holes do not seem associated with any of the test parameters. The first picture is the front side, the second showing the backside having really predominate holes. But again, the parameter differences are speed on the different vertical layers and 5mm retraction all around. My only thought is filament dryness but the filament is relatively new, kept desiccated, and being printed out of a Snapmaker dry box. Other than filament wetness, does anybody have another thought on these seemingly random holes? Thanks.
Correct me if I am wrong, but, it seems to be generally accepted that the optimal retraction distance is around 0.5mm
Normaly I use a retraction of 0.8-1mm @45mm/s for the single extruder and 1mm @35mm/s for the dual extruder.
In my opinion it’s kind of normal to see defectives in such test prints..
Would not agree with Boxkite that there’s an established standard. I have PLA from different brands, and there are differenzes as to how much they tend to ooze/need retraction. Also, going for other materials, the settings may differ considerably - one of the most extreme ones I’ve yet played with is PVA, which oozes as if there’s no tomorrow. For that I go up to 10 mm or so.
Would agree with xchrisd that test prints are exactly for identifying the sweet spots, so defects are a feature, not a bug, as long as you have parts of the test print that look good and tell you what are good parameters. Actually, your print looks very similar to the picture shown on the retration page you linked in.
One thing I personally find important for handling retraction well, and which seems to be missing from the test page, is extra prime amount. Whatever you do, in my experience retraction makes you lose a bit of material, and extra prime amound compensates for that. You do not need much, but 0.1-0.2 mm length - or up to 1mm³ for those slicers that do volumina - have improved my prints.
Thanks for the input. I’m glad to hear that the consensus no the holes is that its an “undocumented feature” and don’t sweat it.
I was using the Snapmaker Luban defaults for most of my prints with only minor tweaks, so the 5mm retraction and the 60mm/s was what Snapmaker loads. I have seen the discussions on that being too aggressive. I did try going to starting at 0.5 and incrementing on 0.5mm (see attached photo). Snapmaker red PLA sure doesn’t like that. The 0.5 was boogers at all the speeds (10 to 70mm/s). It didn’t get better until about 4.5mm/s but 6.5 seems the sweetest spot regardless of speeds (though there were ‘some’ at 40mm/s). And along this side, there were not many holes and most were really small.
@Hauke; yes, I did see the need for extra priming to get this box to work. I added about six lines across the front to be sure it primed (see the string hanging off the front corner). It probably only needed 3-4 lines to settle in, but I have the code and just plug it into what the website downloads each time.
Thanks all for the input.
