Bad PLA adhesion only on small/curved models
Hello there,
I assembled my MK3 kit and aside from a few hiccups everything seems to be going smoothly enough (coming from an Anet A8 it's definitely a whole diffrerent planet!) but I'm having some odd issues with first layer adhesion of PLA on the smooth PEI sheet.
What happens is that if the model is big enough and has long ilnes, everything is fine: adhesion is perfect. When there are smaller lines, or even worse curved lines, it just doesn't stick, and ultimately the nozzle starts dragging the unstuck filament and turns into a messy blob. Even using a brim or a raft doesn't help: with small pieces even those are small, and they don't stick either. (That's actually confusing to me, because rafts with Slic3r PE have the same shape no matter what the size, so they should eiher work all the time or never. Perhaps the issue is that with smaller pieces even the "long" lines are shorter?)
I'm using Slic3r PE with some slightly customized settings for perimeters and the like, but printer-wise it's pretty much stock.
I managed to improve it slightly by raising the bed temperature to 65° instead of the 'stock' 60°, and I generally print at 210° for the first layer and 205° for the subsequent layers instead of the 'stock' 215° as I find my filaments tend to look better.
I keep my fan off for the first layer; perhaps I should keep it on from the get go for small pieces?
The Z height seems to be fine: my "correct" prints have pretty much a solid bottom and are as squishy as they should be (the calibration test results in a full square). I even tried slowing the first layer to 15 mm/s, but it just doesn't seem to help.
What I'm going to try after I'm done with this print is disabling Z lift for the first few layers, just in case it has to do with how the extruder "attacks" the bed, but in the meantime I thought I'd post and ask for advice on what else to test. 🙂
I've been cleaning the PEI plate with 90% ethyl alcohol (isopropyl alcohol is hard to come by around here but I ordered it off Amazon), and once every few prints with acetone. The latter seems to help a bit, so perhaps it's just a matter of keeping it cleaner? (I used to print on glass with the A8 so this is a bit of a new world to me).
Thank you in advance!
EDIT: Well, this is very, very weird but using Slic3r PE's default settings give a flawless print of small models. I'm completely at a loss: the only things I had changed on mine were perimeters, infill and other things that aren't directly related to the first layer, and I had definitely used the same temperature settings before. Moreover, I had re-created my own profiles by editing those default ones as needed, deliberately not carrying them over from the ones I used with other printer.
Can anyone please explain how changing settings such as perimeters and infill may interfere with adhesion? I'm really confused at this point.
Thanks!
Re: Bad PLA adhesion only on small/curved models
Well, turns out it was just a dirty plate. Washing it with dish soap and warm water restored it to perfection. 😀
Re: Bad PLA adhesion only on small/curved models
Good to hear!
Dish soap and warm water are clearly better than any chemicals 💡
Bear MK3 with Bondtech extruder
Re: Bad PLA adhesion only on small/curved models
Good to hear that your problem has been solved. I use an alcohol wipe before every print after the bed has heated. Not sure if it works better than wiping down a cold bed, but it seems to work for me so I keep doing it that way. Once in a while I give it a dish soap cleaning.
The other thing to check is small bits of filament stuck to the nozzle. These tiny "boogers" can get in the way of small features on the first layer. I try to give the nozzle a quick wipe with a soft brass brush before each print. Be careful to only touch the nozzle because there are a few delicate wires nearby.
Steve
Re: Bad PLA adhesion only on small/curved models
Hi Steve,
Thank you for the tips! Since my "fixed" post I've been printing a bunch of things (and I'm oh-so-happy with this printer!) without doing anything in between prints, until literally just now — I got your reply notification as I was washing the plate again.
I just got my bottle of iso-alcohol earlier today and I tried a wipe before the wash, but it was probably not the case. Fingers crossed this thing prints better now, I even put Octoprint broadcasting on Telegram as I have a few friends who apparently enjoy seeing my prints progress (...yeah, I have interesting friends! :D) and I feel a little self-conscious about stopping prints. 😀
I will do the alcohol wipe before each print, I find that sometimes taking things off the plate is impossible without leaving a few smidges here and there, especially with low pieces. I even started printing 2 layers of skirt just so it's easier to grab, may go with 3 actually.
I have been trying to keep the nozzle clean with a paper tissue (much like one would clean a baby's nose, except the latter doesn't burn your fingers if you're a little careless!) as I was recommended against using a brass brush on nozzle with my old Anet A8, as it may scratch the nozzle itself and lead to erratic extrusion. I still have the brush though so I may give it a go.
Thank you for your tips!
Re: Bad PLA adhesion only on small/curved models
Everything was sticking perfectly when I first got my machine. I was able to print multiple items with no cleaning between jobs and I was wondering why anyone would complain about parts not sticking. Then corners started curling up and parts started coming loose.
Now I do a quick alcohol wipe between every print, usually just over the area where the next print will be. I use 50% isopropyl alcohol from the local drugstore.
Steve
Re: Bad PLA adhesion only on small/curved models
I have started doing that too now that I finally found isopropyl alcohol. 🙂 It seems to be going very smoothly so far.
I just have an odd issue with the left part of the X axis making a strange noise when moving at a specific speed (around 60 mm/s) and I'm not sure what it is; I can even replicate it via manual Gcode and it seems to come from the extruder block somewhere. I wonder if it's just lubrication, since it happens only at that speed and only on part of the axis, and the rods are straight (I checked before assembly). Let me ask you, since you certainly have more experience with maintenance: what kind of lubricant should be used on the straight rods? Would regular sewing machine oil be fine?
Thanks in advance!
Re: Bad PLA adhesion only on small/curved models
For reference, it can be heard at around 0:12 . It's really odd as it only happens at that speed!