What the heck happened here???
I've had my i3 MK2 for several months now, and have printed a slew of things using different PLA filaments, all with great success. However, I recently needed to print something that would need to stand up to the high temps of a hot car during the summer, which meant I'd need to take a crack at printing with ABS. It was a disaster at first, but due entirely to the fact that I had no enclosure and was printing in a relatively cool garage. So, I spent a couple of weeks building a really nice insulated enclosure with a top lid, plexiglass front door, side windows, etc. I also whipped up some ABS juice, and was able to get a pretty nice print of the PRUSA logo with a little tweaking here and there. So I set it up to print the little Martian at .1mm as a "final test", and after watching it for a while to make sure it was going well, I headed in to take care of some other stuff. I came back about an hour later, and found this little guy waiting for me:
I've had no shortage of failed prints before, but never anything like this! The print nozzle and sensor are clean - there's no indication that anything was "crashed into". I'm baffled by the fact that so much of it printed *perfectly*, yet mixed in are these enormous defects that persisted for dozens of layers in the weirdest places. The ABS filament was purchased from Amazon with a 4.5 star rating and no reports of anything like this. I started with the default ABS filament settings in the Prusa Slic3r software, and only changed the bed temp to 106 degrees C, and the nozzle to 245 degrees C after some earlier tinkering to determine what worked best.
Any ideas as to what may have happened? I'm still working on a lighting rig for my new enclosure so I can't take good time-lapse photography yet, but I think that'll have to be the next step unless one of you brilliant people out there can help me.
Thanks in advance!
J.J.
Re: What the heck happened here???
Speed and/or temperature needs fine tuning. I would say to fast and to hot on this model. Your current settings may work on a larger print because it will allow the layers to cool sufficiently. Small models need time to cool between layers.
Re: What the heck happened here???
looks as if your nozzle-fan was off.
i know that one should avoid printing abs with fan, but if you have overhangs like at the little marvin, you'll run into trouble without.
furthermore the whole print looks a little bit molten, as if the temperature inside your enclosure was to hot for a while (higher than the vicat temperature of your abs).
personally i wouldn't exceed the heatbed temperature beyond 100°C, especially inside an enclosure (90° or 95°C should do the job).
💡 if you need something to withstand the high temperatures during summer inside your car, you should have looked for the biofila PlaTec filament.
it's between 2 and 3 times more expensive than ordinary pla, but has a vicat temperature of 115°C (ordinary abs has only between 94°C and 103°C) and is mechanical very strong (same tensile stress value with 44N/mm² as ordinary abs).
dem inscheniör is' nix zu schwör...
Re: What the heck happened here???
When switching from PLA to ABS did you do a few cold pulls to clear left over PLA from the nozzle? If not a jam may be in your near future.
Re: What the heck happened here???
Yeah, the nozzle fan was off, as that was one of the default settings, too. The temp in the enclosure can get pretty hot - about 115 degrees F., if I leave both doors closed. That seemed to work great for the "PRUSA" print, but clearly not for this one! I'd done some reading on the forums after my first ABS prints (at 90 degrees C) failed to adhere, delaminated, or curled badly around the edges. Higher temps were recommended, some suggesting even higher than 110 degrees C, so I gave that a shot and had much better results, but I didn't see any apparent improvements beyond 106.
I'll increase the ventilation and try using the auto-cooling settings on the next one for sure. Thanks for all of the suggestions!
Update (Re: What the heck happened here???)
I turned "Enable auto-cooling" on, but not "Keep fan always on", and lowered the bed temp to 105 C for the first layer, and 100 C after that, and the filament temp to 245 C for the first layer, and 240 C after that. So far it looks really good! One problem, though: It cannot keep the bed temp at 100 C - the highest it'll go with the fan cooling the print is about 98 C, but that's only if I seal the enclosure up tight, at which point the air temp gets to about 107 C! So I'm playing around with different gaps in the doors, trying to keep the bed temp and air temp as close to 100 C as possible. Might need to get really ambitious and build an Arduino-based temperature regulator using a servo to open the lid a bit when it gets too hot, and close it when it cools back down. 🙂
Question for the group: Anyone know how hot the power supply can get "safely"? If I attach the temperature probe to the side of the power supply (which is currently attached in the factory location, inside the enclosure) it'll get to 49 C (120 F). Should I consider relocating the power supply to the outside of the enclosure, or is that probably overkill?
I'll post pics of the finished print when it's done. Thanks again!
Final update/last questions (Re: What the heck happened here???)
I misspoke earlier when I said I was trying to keep the bed temp and air temp as close to 100 C as possible - my air temp is in F., so what I was ultimately shooting for was a bed temp of 100 C and and air temp of 100 F, but the closest I could get was 98 C bed, 104 F air. This ultimately proved to be too cold, as Marvin broke free about 1/3 of the way through. And yes, I started with a clean bed and two decent wipes of ABS juice on a cold bed to start. Regardless, what did finish looks SO MUCH BETTER than before!
So, the two questions I have now are:
1. When it comes to the air temp inside the enclosure, how hot is too hot? If the bed is kept at 100 C and the fan is actively cooling the print, is it OK if the air temp hits or exceeds 44 C (111 F)? I'm not sure I can get the air any cooler than that while still keeping the bed hot enough to maintain adhesion.
2. How hot is too hot when it comes to the power supply, and what would be the best way to probe it's temp? I've been taping it to the side of the case and seeing temps as high as 49-50C (120 F). I'm no electrical engineer, but I know that most components are rated for temps much higher than that, but I'd hate to unknowingly kill the power supply. If it needs to be moved outside the enclosure, I think I can make that happen.
I've also posted some photos of the finished enclosure, should anyone care to see. I've got full plans available via Onshape should anyone be interested in them. I initially planned on going with extruded aluminum and plexiglass, but quickly realized that was a tad outside the budget. This one is built using expensive 1x2 lumber and even less expensive laminated styrofoam insulation, plus a few pieces of plexiglass. All told I think it cost about $50.
https://www.dropbox.com/sh/jrokktf2rcn8v1d/AABwiMtgZNg9osOYYDHSaPIna?dl=0
Thanks again for everyone's help!
J.J.
Re: What the heck happened here???
I use a plastic bag over my printer to print ABS that needs to be strong. if its just for looks I print in the open. What issues did you have with ABS before the enclosure? They might reveal more
I print a lot with ABS and I have never seen anything quite like that. it does seem like is way too hot. Is your filament Esun? The reason I ask is because Esun filament needs to be printed pretty cold compared to others.
Re: What the heck happened here???
looks as if your nozzle-fan was off.
i know that one should avoid printing abs with fan, but if you have overhangs like at the little marvin, you'll run into trouble without.
furthermore the whole print looks a little bit molten, as if the temperature inside your enclosure was to hot for a while (higher than the vicat temperature of your abs).
personally i wouldn't exceed the heatbed temperature beyond 100°C, especially inside an enclosure (90° or 95°C should do the job).
💡 if you need something to withstand the high temperatures during summer inside your car, you should have looked for the biofila PlaTec filament.
it's between 2 and 3 times more expensive than ordinary pla, but has a vicat temperature of 115°C (ordinary abs has only between 94°C and 103°C) and is mechanical very strong (same tensile stress value with 44N/mm² as ordinary abs).
Sounds too good to be true!
Must get some of that plaTec to Australia, just what I need for my surfboard fin printing.
Re: What the heck happened here???
looks as if your nozzle-fan was off.
i know that one should avoid printing abs with fan, but if you have overhangs like at the little marvin, you'll run into trouble without.
furthermore the whole print looks a little bit molten, as if the temperature inside your enclosure was to hot for a while (higher than the vicat temperature of your abs).
personally i wouldn't exceed the heatbed temperature beyond 100°C, especially inside an enclosure (90° or 95°C should do the job).
💡 if you need something to withstand the high temperatures during summer inside your car, you should have looked for the biofila PlaTec filament.
it's between 2 and 3 times more expensive than ordinary pla, but has a vicat temperature of 115°C (ordinary abs has only between 94°C and 103°C) and is mechanical very strong (same tensile stress value with 44N/mm² as ordinary abs).
Have you tried the plaTech on the Pruse i3 PEI sheet?
The more I read about it, the better it sounds. (Cough cough, scatch that after some more reading: NOT German, but Austrian engineering at it's best! Sorry ...
Re: What the heck happened here???
looks as if your nozzle-fan was off.
i know that one should avoid printing abs with fan, but if you have overhangs like at the little marvin, you'll run into trouble without.
furthermore the whole print looks a little bit molten, as if the temperature inside your enclosure was to hot for a while (higher than the vicat temperature of your abs).
personally i wouldn't exceed the heatbed temperature beyond 100°C, especially inside an enclosure (90° or 95°C should do the job).
💡 if you need something to withstand the high temperatures during summer inside your car, you should have looked for the biofila PlaTec filament.
it's between 2 and 3 times more expensive than ordinary pla, but has a vicat temperature of 115°C (ordinary abs has only between 94°C and 103°C) and is mechanical very strong (same tensile stress value with 44N/mm² as ordinary abs).
Have you tried the plaTech on the Prusa i3 PEI sheet?
The more I read about it, the better it sounds. German engineering at it's best!
Re: What the heck happened here???
Have you tried the plaTech on the Pruse i3 PEI sheet? ...
Yes, of course, the only problem with the platec stuff is that it sticks like hell at the pei sheet.
dem inscheniör is' nix zu schwör...
Re: What the heck happened here???
One final update to answer a few questions: After two clean but failed prints (breaking free about half-way through) I gave it one last shot, but this time I put a dab of Elmer's glue on the edge of each foot when it had finished the leg, before it got too top-heavy. Within about 90 seconds it had dried clear and all but vanished, and Marvin stayed put for the whole print!
I used a toothbrush with some mild warm soapy water to loosen things up when everything had cooled back down to room temperature, and he popped right off. In the end I went with a nozzle temp of 245 C for the first layer and 240 C for all others, and a bed temp of 105 C for the first layer, and 100 C for the rest. I left the enclosure sealed up tight the whole time, which allowed the bed to maintain 100 C despite the fan working to cool it down along with the print. The air temp peaked at 49 C (about 120 F) and didn't appear to have any impact on the print at all.
I also added some inexpensive recessed LED lighting ($15) in the lid that makes checking the prints SO much easier!
Now that I know I can print both PLA and ABS, I guess it's time to order some of the exotic stiff! 🙂
Thanks again for everyone's help!!
J.J.
Re: What the heck happened here???
@ j.j..s - if you need to print objects that can withstand outdoor sun/heat you should also give ProtoPasta HTPLA a try or MakerGeeks Raptor series PLA. Both are considered "high temp" PLA and can withstand as much, if not more, ambient heat as ABS but they print at PLA temps. I live near Atlanta,GA and it gets very hot(100F) here in the summer, especially inside of a car(120F). I have three different iPhone holders I have made for our cars (2 from Raptor PLA and 1 from ProtoPasta HTPLA) and they have been inside the cars non-stop since last May 2016 and have absolutely 0 deformation or any issues.
To me it is worth the little extra money to get HTPLA and be able to always print at PLA temps and not have the headache of ABS adhesion issues, delamination, fumes, curling/warping, needing an enclosure, etc...
It's another option to think about anyway.