Jeffg1

Thanks! I might be able to give this a shot!

... Also, the hexagonal portion of the nozzle is marked with the letters BB. Not that it would have anything to do with the coding, but this proves beyond reasonable doubt that the core itself is indeed BB and must be a software/firmware coding error.

I inserted a new BB print core in my machine in slot 2 this afternoon, and when I attempted to load a reel of PVA, it said that the material is not compatible with an AA core...?? I unloaded and re-loaded the core, and the same with the material. The core is clearly marked BB 0.4 on the black plastic but the machine seems to think it is an AA. What should I do?

I recently opened a ~6 month old reel of Pearl Gold ABS and found it to be brittle. So brittle that any bending whatsoever caused it to snap. Think dry spaghetti out of the box. Needless to say trying to print it caused several problems, it was cracking as it went through the feeder and the print quality was pretty horrible. Has anyone else seen this kind of behavior on ABS? Thanks Jeff

Will you be bringing it to Rapid + TCT in Ft. Worth next week??!!!

Even with Brass, I would be leery of putting it into the nozzle to try to break away debris. From a clean cold pull you can see from the shape of the plastic coming out that the inside surface of the hotend and nozzle is very smooth and does not have much in terms of defects or machining artifacts. When you put metal in there, even brass, I would be concerned that over time you will start adding scratches and defects, which will accelerate the wear out of the hotend and the defects will create pockets for molten plastic to adhere and remain, where it will break down over time. I also think the defects will create additional friction, which will make future cold pulls more difficult. I think the safest bet is to only put plastic into the hotend.

Thanks all, and I am wondering if the cleaning rods supplied in the maintenance kit are actually polycarbonate, because I have a bunch of that as well.

Further bake-out for another 1.5 hours at 300c yielded more black carbonized bits, and finally a clean cold pull with the full shape of the nozzle. Planning to run a test print and see how it goes. I think for now the moral is that if your cold pull is clean but rough and not the exact shape of the nozzle, you may have some stubborn bits that are stuck to the nozzle wall that need to be burned off. Probably not a big deal on an AA nozzle but from my experience this has caused failed prints on PVA in a BB nozzle.

This is a hot pull after sitting for another 30-45 minutes at 300 degrees. So I think the burn out is having an effect. Going to try another cold pull with the cleaner filament and see where things stand.

I had a BB core that was clogging repeatedly so I took it out of service and just today started taking a deeper look. I have performed about 5 of the machine guided cleanings using PLA and cleaning filament, which produced gobs of yellow and black bits from both hot pulls and cold pulls. But in the end, I am now getting "clean" cold pulls however you can see from the images that there is still evidence of some sort of material that is caked on the cylindrical portion of the print head, and some very tiny bits in the cone shaped portion. My concern is that if I put the nozzle back into service in this condition my problems will continue since we know that perturbations in the flow of a BB core will cause issues with PVA extrusion and subsequent clogging. Beyond the repeated hot and cold pulls, I have also tried heating the empty nozzle (currently at 300 degrees (previously spent 30 minutes at 275 degrees) in hopes that I could convert these bits to carbon and be able to pull them out. So far after pushing about 1 meter of PLA and about 1 cleaning filament through repeated hot and cold pulls I have not been able to get any of these bits free, and each cold pull is similar to the shape shown in the attached images. Any advice would be greatly appreciated!

If you are using a Solex Hardcore with the .25mm nozzle, can you just select the UM AA 0.25 core in Cura without modifying any settings? I haven't tried it yet but just wanted to see if anyone else has experience with using it. Thanks

Interesting! I get the sense that this may be easier to achieve on a different printer. I like the concept but since this is a company printer I'm not inclined to do surgery to it to power the fan from the printer's controller.

Thanks for the lively discussion! Waging war with our safety department is not a path I am prepared to take for many reasons, some already described here by some astute commenters. AbeFM, I appreciate your note about adding a vent fan. I didn't think of that before, and the enclosure lid includes a fan provision for a 40mm fan. I'll try buying one and see if it can draw off enough heat to make a difference in print quality.

I understand what you are saying, but I think my preference at this point would be a software based profile correction. There are already materials that benefit from being printed in an enclosure, such as PC and to a slightly lesser extent ABS. Also, this enclosure is clean, professional looking and commercially available. I would have to go off and make my own wire based solution. As a home based tinkerer, that would not be a problem, in this case as a corporate asset it wouldn't be optimal.

My company's health and safety department requires we operate our UM3Ext with an enclosure installed to prevent pinch points. I have a plexiglass hinged door and a top cap enclosure installed. I find that my prints do not come out as crisp as when there was no enclosure, with the following typical characteristics: Ooze on 1st layer moves warping from build plate pimples on the outer wall of parts irregularity on interface between build material and support material I think these can probably be attributed to the enclosure causing an elevated build chamber temp, and pre-heating of the material in the bowden tubes. My request is to add functionality in Cura to be able to select by machine setting or checkbox to tell the slicer whether an enclosure (door OR door + top cover) is installed, which would automatically adjust the print temperature profiles for all materials accordingly. Is this possible in a future version? In the meantime, has anyone done the legwork on determining appropriate build plate and nozzle temperature profiles for different materials when printing with an enclosure? If so I am all ears! Thanks Jeff