For a Taz 5, you technically don’t really ever have to clean the hotend. I usually pull any strings or crusty bits off of the surface with a pair of needlenose pliers periodically, and I have set up a nozzle wiper like the Taz mini has for general cleaning. I’ve never encountered a nozzle “jam” and most of the ones you hear about (or clogs, etc.) are actually either bits of old fillament that has different temperature properties, or nozzles that are too close to a bed at start, or grinding out due to part lifting or overextrusion, etc. It’s very rarely an actual clog.
Never ever ever ever use a wire brush. There is a risk of shorting out the thermistor or the heater core and destroying your hot end. You can use a mild scotchbrite pad with the nozzle heated slightly. Depending on what you are printing, if you are printing ABS you can wipe the surface down with Acetone. Some people use internal cleaning fillament. I think its generally a waste of money.
If you do the conductive auto leveling (mini style) modification, it becomes very important to keep the nozzle tip clean as well for proper leveling.
Prefferably never. You should only have to replace it if it is damaged, or if you are getting large bubbles. If you are getting large bubbles, it indicates you are putting too much upward force on parts when removing them. You need to change to a better part removal tool that is able to lever small sections of the part away from the bed at a time. The caphalon gadgets cheese wedge with the slicer bit taped over works great for that. Or a paint scraper. If you do have a large bubble, you can remove the PEI sheet by placing the entire bed assembly in the freezer, waiting for the PEI to get cold enough to separate (probably several hours) and then peeling it off. Then you can carefully remove the adhesive sheet, using something like goof off or other orange oil based solvent sparingly and carefully so as not to separate the heater core to remove the rest of the glue. Clean the surface 3 times with glass cleaner, then apply a new adhesive sheet and reapply your PEI. The PEI sheet does have two different surface profiles, so unless it is damaged, you generally want the normal print surface “up”
Those Mr. Clean Magic Eraser white sponge thingies work really well.
You will want to apply white lithium grease to the leadscrews (the threaded rod bolt looking things) periodically. You never need to apply any lubrication or oil to any of the bearing rods, it will actually gum them up.
You will also want to check all the setscrews periodically, the Z motor couplers, the small gear setscrew on the extruder, the small setscews on the X and Y pulleys. Check the belts for tension, inspect the idler arm, the large gear and the small gear for damage as they are wear parts.
@piercet THANK YOU! great reply. I found it very helpful and informative.
re: wire brush - surprised about the wire brush (especially given it was one of the tools included in the bag that came with the printer).
re: PEI sheet - great news about not needing to replace them. Quick follow up question: how much damage is acceptable damage (e.g. scrapes/scratches from stubborn parts)?
re: auto level mod - I will definitely look into auto leveling modifications. I’m never fully confident on my leveling and still uneasy with the paper trick. looking at the bottom layer of the print gives me the most confidence, but this approach results in lots of trial and error. I’m still unsure how often need to check/adjust leveling too. (any low tech tips here would be greatly appreciated as well.) ).
The wire brush is there to remove gunk from the hobbed bolt inside the idler chamber. The risk with using it on the nozzle is that you will puncture the insulation on the heater core and short things. It has happened to more than a few people.
That looks like either idler arm tension or a hobbed bolt that needs cleaning at first glance. in the other thread.
Check the screws on the motor mounts every so often also.
On the PEI sheet: If you see small cracks in the sheet you are going to need to replace it very soon. This happens as the cooling part stresses the plastic surface and will cause the plastic to fail and let oils and dirt(AKA GUNK) into the adhesive layer.
On clogs they can be caused by ‘foreign material’ passing into the top of the extruder along with the Filament. Aka dirt, saw dust, metal flakes, small BUGS, and other non-melting items.