12.2
Hot End & Nozzle
Keep your Hot End Nozzle clean, don’t let molten plastic build up on it as this will cause issues
when starting prints. Brillo/ Scotch Brite Pads or a scourer are a good way of keeping it clean.
It’s easiest to keep it clean as you go, by using tweezers to remove excess plastic in between
printing and not letting it stick to the nozzle.
Visually ensure wiring and connections haven’t moved and are still located in their correct
positions, pay special attention to the hot end thermistor, if this moves away from the hot end
heater block it will result in the electronics applying more power to the hot end to maintain it at
a higher temperature as an offset to the thermistor being further away, this could result in the
electronics cutting the power to the hot end as too much current is drawn. This would then
result in the hot end cooling mid print, and then the filament will grind out in the extruder and
you will need to reload the extruder and start the print again
Check the nuts and washers across the printer to ensure they are still tight and haven’t worked
loose, as the printer move’s and vibrates a lot, it is prudent to check these regularly. It is
important they don’t work loose as it can affect the geometry and stability of the 3D Printer
12.3
Nuts & Bolts
The Extruder is one of the hardest working parts of the printer.
Every so often open the extruder Idler and clean out any loose plastic and plastic debris that
may have built up on and around the hobbed bolt. Using a small tooth brush or hand held
vacuum is very effective, clear out any loose debris, you should do this everytime you change
filament anyway.
Visually check the drive and driven gears for wear and to ensure no teeth have broken or
become damaged, this might not be obviously visible, make sure you look closely. This could
result in uneven/inconsistent extrusion.
Check the drive and driven gears still consistently mate together tightly.
Check that the hot end is still tightly clamped into the extruder and is still located in it’s original
position, in that it hasn’t moved or slipped at all.
12.4
Extruder & Gears
12.0 Maintenance - Reprap Prusa Mendel Build Manual
©2012 NextDayReprap
Prusa Mendel Kit Build Manual V1.01 - 07/2012