Semi-Chamber for PLA? (Sides On Door Open)

[m00dawg]

I've been trying to track down a problem I feel like I started having somewhat recently where my large flat PLA parts will tend to warp after coming off the (cooled) heat bed. I thought printing with some infill (rather than solid) might help but I think it might actually be making it worse. One change I have made recently-ish was to have the sides off the printer (a 2.4 in this case). When the sides and doors were on, I would leave the doors mostly open when printing PLA. That caused the chamber to get somewhat warm and while it proved problematic with some PLAs I think that was perhaps the better overall situation since the part stayed warm through the printing and kept the top parts of the part warm longer while the heated bed cooled. I wanna say with that setup I didn't get warping after removal. I should say it's only some parts too, but it's the parts which are larger and thicker than my other, smaller, mostly flat parts. For instance I print flat parts on my complete open Trident with no problem but we're talking 2mm vs 4-5mm worth of thickness. The parts do have some geometry, but it's still lots o flat stuff rather than complicated sculptures.

Curious what other folks printing flat parts in PLA are doing in terms of panels vs no panels?

 

[claudermilk]

I have the top and doors off, sides are left on. I also revised my bed temps to stay the same throughout the print--not lowering after the first layer.

 

[m00dawg]

Trying a print with everything on, but doors open just to see how things compare. The reason I took the panels off in the first place was when I had to do maintenance on the gantry. I'm not expecting a huge change but something changed between when I first started printing these parts and now. Good point on the bed by the way! I've long since been using the same bed temp for all layers as well but I wonder if maybe I should consider different temperatures. Too low and the model will start to get corner lifting though.

 

[m00dawg]

I dunno why I didn't think of this sooner. I happen to have a larger t-shirt/vinyl press and figured may as well try it. So I heated it up to ~50C, pressed it down onto one of my parts that was giving me some warping, then let it completely cool like that. To my surprise it's super flat! I'm going to try that on a few other parts to see if it's reproduceable but that might actually be a good option for me.

 

[leograyc]

Just to throw in a datapoint. I actually print PLA with my door closed. I do print some box-parts that are 200mm square, with no top-btm surface, exposed 30% cubic infill. No warping problem.

I was recently playing around with the idea of auto part eject by letting the printhead push the part out, and changed the front door to a shower curtain. This also worked well for me.

I wonder if you should let your part fully sticked to the print-bed, smooth bed, until it's fully cooled down, and then peel it off ? Specially using a smooth-bed so it doesn't pop itself off during cooling.

 

[m00dawg]

I'll have to try that. I have found my flattest prints seem to be with the doors cracked. So might be worth trying it closed. These parts don't involve any overhangs so the only real risk is a heat creep with the nozzle. I have a Honeybadger super high speed fan cannon on the heatbreak so that risk might be somewhat low. Just started a 2.5 week vacation so that's something I'll have to look at once I get back home but I think there might be something to that.

 

[leograyc]

I got the same honeybadger 10k rpm fan for cooling the hotend. My CANbus board is reading 50C on itself when I'm printing (shower curtain closed, with some leaks). I think the chamber temp is not that high, but like 40+.

 

[m00dawg]

It's LOUD but I really like that HB fan. I'd run it on my Trident too but the pin connectors are different (smaller) and I haven't bothered to look at recrimping. Kinda waiting on Nitehawk (or, brightest timeline, Nitehawk+ with a USB header for Beacon).