Originally posted to a reply in X1 forum about adhesion issues and slight warp in bed.
I checked my other branded machines (Prusa, Creality, and others) all have a slight warp. Nothing is perfect. I started having adhesion issue with some off-branded PLA, a rainbow one, seem like many used it, though it was problematic for me. I researched and found some articles about enclosed printers and too much heat, though other articles stated they did see enclosure as a potential cause of lost adhesion. I tried cleaning, washing the plate, various temps, and slowing it down.
EDIT - To be clear, this was an off-brand of filament. PLA with this enclosure from more well-known brands has not been an issue.
So what I did, following one Reddit post, was I removed the top cover. BAM, no issues. I am on 5th bulk print (10 of the same model on the plate). So the excessive heat build did play a part, it appears. Even with the slight warp and printing pretty close to the edges.
I do more PETG, so the enclosure is excellent for this, and I vent via a fan through an AC Infinity filter.
If you want to know about enclosure, and yes, I overspent, and if at the time I could, maybe just have gotten the X1, but it worked out very well, and I like the orange panels. It’s from ClearViewPlastics
PLA PTEG = no enclosure. If you enclose your printer and try to print PLA it fails. PTEG sometimes works.
Encloses on 3D Printers are for ABS ASA etc… Hard plastics that warp need a heated chamber. Heated by a heater or print bed.
If you print both ABS and PLA a enclosure system that the side panels are removable for PLA PTEG are best.
So re-read this part - I started having an adhesion issue with some off-branded PLA, a rainbow one, seem like many used it, though it was problematic for me.
I am not saying that fully enclosed does not work with PLA, it does. Like @PrinterMcgee I print in PLA all the time with the top on. It was this particular PLA that was causing an issue. Oddly, the lid off helped in this siutation.
Again I do exhaust air for safety reasons, and I could try turning the exhaust fan up in speed as it will pull some air from the outside enclosure and see if that makes a difference for this particular brand filament.
My apologies to the forum and to @dingchow , I should have been more clear and taken more time to think through the title and post.
So again, this filament, lid off worked great for it. However, I do print plenty of PLA with the lid on without issues, and those are more common brands, Hatchbox, Polyterra and Polymaker, Matterhackers, and more.
To be fair, for the X1C the BL Wiki (scroll to “Bed settings” section) explicitly mentions, that the top glass cover may be removed by the operator if bed temp >= 45°C. I guess this also applies if your P1P is fully enclosed.
I ran into a similar problem with some prints warping off the bed with PLA. After a while I started realizing that nearly all of the prints were due to a single roll of filament, and I actually did a fairly thorough investigation of the particular print across multiple materials.
Conditions:
The particular print was a SHARKZ clip from Thingiverse, with two copies, one closer to the aux and one further away. No brim. Used cool plate.
The filament was a fairly old roll of Hatchbox Black. While many people consider this to be a very consistent filament, I heard that during the pandemic they had severe supply chain issues and were constantly switching material vendors. This roll had been purchased at the peak of the pandemic.
I purchased a new roll of Hatchbox Black and the problem was not present at all.
I’ve tested for warping on multiple brands of material - Bambu PLA basic, Fremover, and none of them had issues with this print at all.
Observations
Liquid PVA glue and glue stick both helped, but were insufficient for the bad Hatchbox roll. Without the glue it’d peel off before completing the print. Both were necessary on cool plate for all of the other filaments to prevent the edges from curling up.
For the “bad” filament, hotter cool plate temperatures (45C) and turning off the aux fan helped. I think curling stopped altogether with 40 or 45C build plate + no aux fan. Obviously with less cooling some line quality starts going down for PLA.
I did not try opening the top cover, but probably should have. I already printed away the “bad” roll to save myself from the trouble.
General notes on PLA based on my other observations:
Warping is caused by a balance of two factors - curling force due to shrinkage from upper levels of the material and bed adhesion.
An imbalance between bed and chamber temperature or cooling rates for newly deposited material can cause high warping forces.
PLA also softens at higher temperatures (>55C) and at high enough temperatures, can begin to crystallize which typically results in a sudden shrinkage, probably in the direction of extrusion. I doubt many people are running into this problem as you really have to try to get >55C chamber temperatures.
My guess for this “bad” batch was actually that it was an adhesion problem - perhaps the extruder was using some lubricant that never got cleaned off of the filament. I think it was very easy to pull material off the build plate.
Another thing that can happen with an enclosed box (I have made this happen before - but when pushing bed temps way beyond 60C). At high speeds you often find that you have to push the temperatures of PLA all the way to the max to ensure good material finish and z-layer adhesion for some materials. The higher chamber temperatures due to both hotter beds and enclosure can result in the cold end of the hotend assembly to exceed the softening temperature of PLA (which is only 55-60C, depending on brand) and jam your entire assembly.
I think for all these reasons Bambu recommends cold plate + glue stick + open top for PLA. It gives you the most likelihood of almost every single filemant on the market, even slightly defective ones, to work reliably. I never tried open top for the bad filament (my AMS is on top of the machine…) but I suspect it would have helped.
In summary…it’s a complicated issue and I’ve actually gotten most PLAs to print just fine in both enclosed and unenclosed machines (X1C and P1P). If you can tolerate the glue, I think cool plate is better overall due to lower power consumption (print cost) and generally better tolerance to both enclosed and unenclosed machines across different brands of PLA. I haven’t had a failed PLA print yet on a PEI plate but I would imagine it could be higher, and adhesion appears to be worse than glue stick.
[EDIT]
I forgot to mention! I was printing the Sharkz clip with 6 wall loops to improve the clamping force of the clip. This is very close to effectively 100% infill, which drastically increases warping force for the part. In general higher infill parts cause a lot more thermal gradients in the part during printing and will probably help show peeling problems at their worst.
