The process of bed leveling is fine when the nozzle goes to all the points. After that process the nozzle heats up and then the Lidar scans the bed where the print will lay down filament. It’s not a problem on small prints but on bigger ones there is a bunch of filament that gathers on the head and sometimes ends up dropping off in the middle of the bed. This is mostly a problem when using PETG or other high temp materials. How can I make the nozzle heat AFTER the lidar bed scan? Thanks in advance
3 Likes
I have noticed this too with ABS since that is primarily what I print in.
1 Like
I’ve noticed this as well. You would probably have to modify the g-code to change the heating sequencing.
I started with the Generic PETG profile when slicing. After a lot of oozing, I noticed that the preset was preset to 250C for PETG. I dropped that to 230C and have experienced less oozing during the timeframe that you mentioned, but it’s still there. I’m still in the dial-in process. I probably need to drop it lower to maybe 220C. Anyway, it doesn’t directly answer your question, but you might get some improvement with this method, if you haven’t already tried it, which is easy to change in the Bambu slicer settings.
1 Like
That is what I have done so far. Simply dropped my temp on PETG to 240. At least now it’s not as much and usually does not release onto the plate until the purge line. But I would still like to edit g code to have this done before the nozzle temp increase. Im just not that familiar with the bambu g code yet.
1 Like
What’s causing me some uncertainty is this quote from Wham Bam: “Bambu raises the temperatures of the hot end in their slicer so they can push more plastic through the hot end and print at incredible speeds.” So, maybe changing just the first layer slicer temperature is the way to go, whereas, without knowing why it had been set to 250C, I had crudely set everything to a lower temperature.
1 Like
I’ve had this issue with the BL CF material that came with the printer. I’ve tried a few things in the slicer/material profile with minimal success. Dropping first layer temp with this material worries me due to clogging, etc. but after checking it does appear that all first layer temps are quite high considering how slow they print. All things considered, I will be trying this in future prints to see how it works out.
BTW! The oozing itself hasn’t really caused an issue with the prints that I find to be detrimental other than minor cosmetic issues. Don’t get me wrong when I see material strung all over the bed after the first layer I get really nervous but so far it’s been manageable. I’m kind of surprised it doesn’t detect it and give an error though.
2 Likes
I tried it yesterday, and it seemed to help.
Trying it more today, I notice there’s a problem: it doesn’t wait to heat up the hot end between the first layer temperature and the hotter second layer temperature. Rather, it plows ahead at high speed while the hot-end is catching up. Luckily, in my case, it hasn’t jammed yet, but it’s not ideal for the general case.
Bah, I bought this machine so I wouldn’t have to fix stuff like this. 
I’ll just use it as is and hope for the best. YMMV.
Its funny because on a typical bed slinger you usually need first layer higher to help with adhesion but in this instance we are adjust for ooze. My thoughts about the speed and temp is much differant for this printer than an Ender running Klipper at high speed. Enders hot end is not built to push filament so quickly and is the reason we push the temps higher BUT Bambu’s hot end is meant to run at this speed so its built differently. My guess and my findings show that i run my filaments at the same temp i did on my ender. My first PETG print i didnt even look at the temp but its set manually to 250 which is the higher limit on most. If you get your temps correct for the filament it shouldnt be oozing like crazy and when i drop it down to 235 or 240 it seems to run perfect and also very little oozing. Another thing i noticed, if using the bambu pei textured sheet the scan is bypassed. While i dont have a bambu plate i do have a picture of the qr code which i printed and glued to the plate. So now when starting a print it scans qr code and does not scan the bed. Not ideal, but it works!!!
1 Like
@Droopydroors42 Why doesn’t it scan on the textured PEI?
Noticing that different brand PETG’s can perhaps have meaningfully different heat ranges listed on their stickers. Based on my oozing experience, I’m switching from DiKale (210-230C) to Sunlu (220-250C), which will maybe be more inline with the default temperatures used by the Bambulab slicer’s “Generic PETG” profile.
I believe the reason Bambu has stated is the lidar has issues with the textured plate. I have used it on the textured plate without issue but this is the reason it is skipped. As far as the filament brand and temps i was having oozing issues with Polyterra which is the same range as recommended in Slicer. But going to the lower end of the scale seems to do well.
I don’t see that PolyTerra offers any promises regarding the consistency of the diameter (e.g. + or - 0.02mm). I know that Prusa has made a big deal about diameter consistency in its Prusament filament. He claims it has a big effect on print quality. I suppose a lot of variability might also have some effect on oozing.
I think the problem is only on the pressure advance calibration. Because the surface is uneven, therefore the lines put down during pressure advance calibration are not consistent enough to really work. Otherwise it should be fine.
1 Like
Switching to Sunlu solved my oozing issues. Glad it was so simple. Who knew? Mind you, I’m not promoting that particular brand. Just sayin’.
Funny enough I was searching for an answer because I was having issues with oozing on Sunlu PETG. So I am curious if you changed any settings or did you keep the stock settings?
2 Likes
Stock. Have you kept your filament bone dry? If not, that could be a source of oozing, not to mention stringing as well. If you leave it exposed to humidity, it will pick up detrimental amounts of moisture in about a day.
I havent experinced any stringing and I noticed it oozing straight out of the bag. Not sure if it already has moisture from the factory tland I will just have to try drying it. Otherwise I am not sure what else could be causing it
1 Like
I’m getting some whispy stringing today that I didn’t have yesterday, from just letting the roll sit on the back of the printer in the garage. For what I’m doing, not a big deal. Thankfully I haven’t had a “Blob of Death” experience on the Bambulabs printer, but for that reason I stay vigilent against possible oozing complications.
I’ve been tinkering with the material profiles for the last week and noticed that the retract is EXTREMELY LOW! Only .8MM which, at first glance, seems to be insufficient for a lot of materials.
It’s most likely due to the speed of the printer, so that’s the tradeoff. You can override this in the material profile. I’m using what the manufacturer for my filament recommends: 3MM!
If you’re having ooze issues, Change this setting!
2 Likes