TLDR: Is it possible print PLA, PET, conductive PLA and nylon with stock style extruders? Is the solution lowering the print temperate to reduce heat-creeping or is lubricating the filament with oil really the most viable option? Is there something I'm completely missing?
I've been running a 2x at work for a few years now and a year ago I got materials other than ABS, a few spools of PLA and PET. Its been able to print ninja flex decently although parts would suffer from a little overheating. ABS has never really been an issue for the printer and I was successful early on with PLA but it would always stop feeding mid print. Specifically the filament would slowly stop feeding after a few layers and eventually start grinding on the drive gear. This had all been with a completely stock printer.
So back in the beginning of the summer I replaced the nozzles with Fargo Printing replacement nozzle assemblies and the stock filament drive assemblies with some machined aluminum ones off amazon. I also added a cooling fan for the filament on the front of the gantry. That was the easiest part of the whole upgrade because the main board already has a dedicated connection for a fan and Simplify3d is able to activate it. The upgrades fixed some old feed and extrusion issues the printer always had. At that point I went back to trying PLA and ninja flex. The cooling fan makes a huge difference with the ninja flex and PLA but the PLA would still stop extruding mid print.
Shortly after upgrading the 2x, I upgraded my own printers with good all metal extruders and learned about their advantages. That's also when I learned that the internal lubrication coating and heat break are critical to making them work so well. I though since the 2x stock nozzles are essentially early versions of all metal extruders the problem was the filament drive assembly. After thoroughly checking prints I came the conclusion that the drive assembly is able to push the filament much harder with out it grinding and the issue was with the extruder. One thing I think that has been happening is heat-creeping up from the heater block into the thermal barrier tube. The stock designed tubes don't have much of a thermal brake and the way it mounts the the assembly block does not allow for much heat to be drawn off. If the thermal barrier tube overheating the filament then I'm assuming lowering the temperature would resolve that issue. I played around with that earlier this week and found it helped a bit but lead to layers adhesion problems and outer shells not extruding at the start.
Looking at other solutions, I've come across a lot of talk about lubricating the filament with something before it goes into the extruder. The idea being that the filament is expanding inside the thermal barrier tube and sticking to the side walls. Pre-lubing the filament would help the potentially clogged filament I really don't like the idea of doing that. Not from a fume or fire risk but just because that's just another variable to account for when trying to run an already old and poorly designed printer. I'm also thinking the new thermal barrier tubes are much like the stock ones in that they completely lack any lubrication on the side walls. I was reading further that ABS would not be as prone to problems like this because it supposedly flows better when melted when compared to other plastics. PET, PLA and softer plastics don't flow as well when heated or even bind to the thermal barrier tube more than ABS. To me that makes since because I've always been able to print ABS throughout all of this.
I'm really just rambling at this point. I've been trying to get the most out of this printer for years and want to be able to successfully print more than ABS. I want to know who else has voided their warranty by printing anything other than ABS or HIPS in their 2x. Also if there is something I'm completely missing please chime in.