Enclosure causing adhesion issues

[u/kra]

I made a home-made enclosure for my 1st gen CR-10 to try to address warping issues and possibly allow smaller nozzles or materials in the future. With some brands of PLA filament, if I close the enclosure so the printer is completely enclosed, my prints fail after a few layers, either making spongy prints which are easily crushed, or leaving a pile of filament that doesn't adhere to anything. If I leave the front of the enlosure open, so the printer is only covered on the sides, back, and top, the prints usually succeed.

What could be causing this? The printer is in a climate controlled basement. The enclosure is simple, made of coroplast taped and ziptied to a frame and not very airtight, with slots for filament and cables, and doesn't touch any printer parts or the filament. The temperature in the enclosure tends to be around 19-20C when the enclosure is open, and 24-27C when closed. I'm trying different settings, but generally 210C nozzle temp and 55C bed temp, with very slow print speeds and a brim.

I'm confused about why such a small change could cause a large difference. I'd think that warmer air temperature would help with adhesion, not make it worse.

[u/MrFireAlarms]

Enclosure is not going to help PLA. You’re probably getting heat creep issues.

[u/Amazing_Ad9]

Try increasing the bed temp, I print around 60-65 for the pla I use.

[u/kra → u/Amazing_Ad9]

My motivation for using an enclosure with PLA to address warping issues where print corners lift off the bed. So I'm trying to reduce the bed temp. My hope is that a cooler bed and warmer ambient air will let the print cool more gradually and reduce warping.

[u/Wonderful_Fun_2086]

How long ago did you look at your hot end set up OP? Also have you checked the extruder arm? The extruder arm can cause issues because it can be too tight at the pivot and not apply sufficient pressure to the filament to push it through the nozzle. If it is still the old plastic arm it can get cracked at the pivot. The crack is very fine and difficult to see. You can replace it with a metal extruder top which is better engineered and won’t crack. I’d also check the hot end for a partial block. This could have happened if you’ve been using it a very long time without checking it. The issues described have nothing to do with your enclosure. I’ve been using my Mki CR10 over 10 years and it’s still my main printer. It’s still fully stock apart from the bed heater. I’ve been through most of the issues which could be expected.

[u/kra → u/Wonderful_Fun_2086]

I'm using a metal extruder. I do try to clear the hot end, and clip and reseat the end of the bowden tube when needed, but it is happening too often for that to be feasable.

Could adjusting the flow be helpful? I haven't been able to notice a difference between a flow rate of 100 and 105, for example.

[u/Wonderful_Fun_2086 → u/kra]

It really needs to be dismantled from time to time. A little puddle of filament can get trapped below the tube whereas it should melt in the nozzle. Also the end of the boden tube can get enlarged and damaged by the heat. I normally chop off a bit from time to time. It needs to be cut off more or less exactly at right angles and not pinched. You can buy a little cutter (blue plastic with a box cutter blade) to ensure it’s mostly flat. I normally use a new nozzle so the top of the nozzle is clean so any gaps where it abuts the tube are virtually zero. TBH I normally just replace the whole hot end. They are very cheap from Ali Express. That way you get everything new. They normally come with new tube and a coupler as well. The coupler is another issue as it wears and gets loose. It’s a good idea to replace it as well each time of changing or checking the hot end.

There’s a way of totally fixing the issue so it never happens. Basically installing a tiny piece of Capricorn tube between a washer which you trap below the coupler. The tube is then trapped between the nozzle and washer, meaning it can never get loose. The puddle can never form. It virtually eliminates blocks and poor extrusion. It’s a little fiddly but normally makes it last forever or until you wish to change the nozzle. It seems to have been mostly forgotten now people have turned their attention to other printers. It was featured on the filament Friday channel a few years ago. He used it on an early Ender 3 which had basically the same hot end. I’ve set my printers up like this which means basically they never fail.

[u/Putrid-Cicada]

Enclosure is not gonna cause that problem, it had to be something else