01. Assemble the HotEnd

Do not tighten.

Secure the heater cartridge with an M3 set screw.

The thermistor is small and fragile. Be gentle with the legs. The thermistor bead is made of glass - don't crush it!

Slide the glass-fiber high temperature sleeving onto the legs of the thermistor. Make sure to get the sleeving all the way right up against the glass bead.

Bend thethermistor legs 90 degrees about 2-3mm behind the glass bead.

The legs must be fully insulated next to the bead. Careful about the sleeving - it will want to slide away. Keep it right against the bead.

Due to the manufacturing process, washers often have slightly sharper edges on one of their sides.

Make sure to have the smooth side facing away from the screw head - this way the smooth side will be against the sleeving and won't damage the insulation.

M5x5 button head screw.

Secure the thermistor in place with the buttonhead screw.

Don't overtighten - you don't want to damage the insulation and short-circuit the thermistor.

Visually check that the sleeving is insulating the legs of the thermistor right down to the bead.

If the legs make electrical contact with the block or each other your temperature readings will be incorrect and you risk overheating.

Split the thin double wire about 5cm and slide heatshrink pieces on both legs.

Strip about 1.5cm (1/2'') of insulation from the wire ends. Use a wire stripper, knife, snips, scissors, fire, teeth, or a combination of these.

Slide on two ferrules onto the thermistor legs.

It does not matter which wire is which. The thermistor does not care about plus and minus.

Crimp the ferrules by firmly crushing them with a pair of vise grips/ pliers.

You can use a fancy ferrule crimping tool if you have one, but it's not needed.

Slide the heatshrink down over the now crushed ferrules and shrink into place with a heat source such as a soldering iron, hot air gun or a flame.

The PTFE tubing is mandatory, you must use the tubing or the HotEnd will not function properly.

The tubing should be inserted from the top of the now assembled hotend and pushed as far down into the hotend as possible at all times.

The end of the tubing that is inserted into the hotend must be cut cleanly and squarely with a razor.

To release the tubing from the heatsink simply press down on the black collet in the top of heatsink while pulling on the tubing.

Note: As of summer 2018, we ship our hotends with a premium high-temperature blue PTFE tubing. Rejoice.

Inset the PTFE tube all the way through.

Then, push it back up (as much as the black collet on top rises) so that about 2mm of the tubing ends up sticking out of the threaded end.

The PTFE guides the filament from the cold side of the heatsink right down into the hot nozzle. For it to do so effectively it must butt up against the nozzle squarely and be positively secured in that position.

Cut the PTFE squarely against the stainless heatsink with a razor blade, x-acto knife, or other very sharp cutting instrument.

Gently bend the red heat cartridge wires at about 90 degree angle straight back (see picture).

Unscrew the nozzle about 1/2 of a turn (180 degrees) to create a small gap between the nozzle and the heatblock.

Screw in the heatsink all the way to touch the nozzle.

The wires will sit between the heatblock and the heatsink.

Shrink the leftover heatshrink at an appropriate place.

The PTFE should be sticking out on the top and not moving in any direction.

The black collet should be all the way up.

None of the heatshrink should ever touch the heatblock. Only the fiberglass sleeving can withstand printing temperatures.

There should still be a small gap between the nozzle and the heatblock. The gap can be smaller than the one in the picture, but some gap must be there.

Before you can use your hotend, you have to perform a Hot Tightening' procedure. Hot tightening is essential to sealing the nozzle and heatsink together to ensure that molten plastic cannot leak out of the hotend in use.

A) If this is the first time you're assembling the hotend, you're done for now! You'll do the hot tightening once you have an otherwise functioning JellyBOX.

B) If you already have some JellyBOX built, then you may go ahead and follow the Hot-Tightening Guide.