Bizarre Enclosure Induced Failure

[Brian]

I have been printing some very large parts that reach the edges of the build volume and started to have layer separation with the ABS I was using, so I decided to hack an enclosure around the printer and I had much better results at first. I thought I could get it even better if I added a heat source to the enclosure, so I put a 100W light bulb in near the top. The print came out perfect!

I was done with that print and went back to making smaller parts right after that, and so I took the enclosure off and printed some small items. When I checked on them, they were totally messed up. They had layer shift and alignment issues. I was totally puzzled, so I cancelled the job and went to lift the extruder up by hand to get it out of the way, and I discovered the extruder was flopping around like a wet noodle. When I looked closer, the cause of this is that ALL THREE of my cheapskates were loose. They were just barely riding in the grooves, as the screws were all loose and the adjustment cams had become loose.

I can only imagine that the hot chamber had caused something in the cheapskates to expand, and when the printer was cooled, they loosened up. I have never had any troubles with any of them before, so this must be what happened.

[gestalt73]

Hey Brian,

That is very strange. although I've never used a light or heat lamp in my Hefty Trash Bag enclosure, I do tend to print most items enclosed now. I recently opened up a vent towards the top, because I was a little worried that it was getting a bit too toasty in there.

I'd think that anything hot enough to melt the melamine would warp it permanently.

The V1s use melamine panels for the cheapskates, do the V2s use the same?

I'd really like to get more input from people like you who have successfully printed large items.

I've had pretty good successes printing full bed parts, but I had to really crank up the temps and keep the print speeds reasonable.
Otherwise the parts would split.
(Disclaimer, I've upgraded to an E3DV5, if you're using the stock hot end, you can't go much above 145c.)

I'm almost finished printing a full bed, 60 hour ABS print for a client.

Here's how I've been accomplishing full bed prints:
using an enclosure
0.20mm layers
280c for first layer and all other layers
120c bed
20mm/s perimeter, 30mm/s inner, 40mm/s infill

I know there are people on the board that insist that I shouldn't have to print that hot, but any cooler and I get splits. I'm sure I could lower the temps a bit if I slowed down, or went to 0.15mm layers, but that would take forever to finish.

The main problem with large prints, is that each tweak to settings can take day(s) to see the results of. Some of what I'm doing may be unnecessary, but I don't have alot of time to fiddle with it and find out. And alot of the things that I'd do on smaller prints simply don't work on large prints.

I might even have a split or two on this part, I'll know for sure when I get home tonight.

[Eric]

Do you know how hot the top of your enclosure got?

100W is a lot of heat to add to a closed box that already has heat sources in it. I wouldn't do it unattended unless there's a thermostat involved...you could come home to a fire.

[Brian]

Hi Eric,

I was mistaken, the lamp was a 60W, so it's not quite that bad as you thought.

Don't worry, I did not leave the printer unattended in this configuration. In fact, I got an extra smoke detector and mounted it on the ceiling directly above the printer, so even if I stepped out of the room for a moment, I would get a quick warning if something went wrong. I also installed a fire extinguisher when I first built the printer, so I had that ready too.

I will probably ultimately build a controlled heater for the enclosure. I just was interested to see if it could make a difference. It really does seem to help, but it looks like I let it get too hot inside.

I suspect that the extra hot enclosure caused to nylock nuts to loosen up, that's the only thing I can think of.

BTW, after setting the cheapskates back right, and recalibrating the Z heights, the printer is back to functioning and making great prints.

[Brian]

Hey Brian,

That is very strange. although I've never used a light or heat lamp in my Hefty Trash Bag enclosure, I do tend to print most items enclosed now. I recently opened up a vent towards the top, because I was a little worried that it was getting a bit too toasty in there.

I'd think that anything hot enough to melt the melamine would warp it permanently.

The V1s use melamine panels for the cheapskates, do the V2s use the same?

I'd really like to get more input from people like you who have successfully printed large items.

I've had pretty good successes printing full bed parts, but I had to really crank up the temps and keep the print speeds reasonable.
Otherwise the parts would split.
(Disclaimer, I've upgraded to an E3DV5, if you're using the stock hot end, you can't go much above 145c.)

I'm almost finished printing a full bed, 60 hour ABS print for a client.

Here's how I've been accomplishing full bed prints:
using an enclosure
0.20mm layers
280c for first layer and all other layers
120c bed
20mm/s perimeter, 30mm/s inner, 40mm/s infill

I know there are people on the board that insist that I shouldn't have to print that hot, but any cooler and I get splits. I'm sure I could lower the temps a bit if I slowed down, or went to 0.15mm layers, but that would take forever to finish.

The main problem with large prints, is that each tweak to settings can take day(s) to see the results of. Some of what I'm doing may be unnecessary, but I don't have alot of time to fiddle with it and find out. And alot of the things that I'd do on smaller prints simply don't work on large prints.

I might even have a split or two on this part, I'll know for sure when I get home tonight.

My part is EXTREMELY problematic because it is about 10 inches long, 5 inches high and is about 3/8" thick. It would be better to print it laying down, but the corners come off the edge of the build plate if I print it laying down.

The super hot enclosure did make it print, but the print got sloppy for the last few layers, I assume because the cheapskates loosened up. The melamine did not melt, only the screws in the cheapskates got loose.

Does printing thinner layers help with splitting? I could do that.

Also, does a hotter extruder really help? I thought the issue was that there was too much shrinking and that would be worse with more heat?

[gestalt73]

There was another really helpful post in the past about what another guy did to print large parts.

There are a few settings that I borrowed from him, totally makes sense, and seems to help with shrinking:
- 2 perimeters
- 20% infill

I print all my large parts with those slicer settings now.

The part I just completed was 11"x8"x5", but it's more of a shell, with more then half of the print volume going to support material.

I've also printed full plate flatter parts using the same settings.

I started printing large parts cooler, and everything was "split city" until I bumped it up to 280c.
You can't get that high on the stock hot end though, I've upgraded to an E3DV6.

There were even splits for me at 275c on a couple of different models.

I'd love to hear other people's settings