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V6 Universal Hotend Assembly (1.75mm Version)

Warning: Before you start assembly, please read the following important information:

  • Hotend comes lightly pre-assembled to give you better idea of the assembled product look. You should not rely on this assembly. To prevent leaks and ensure reliable operation, you have to tighten parts as it will be described below.
  • The heatbreak is fragile. If you are using a large spanner, hitting it with a hammer, etc. It will break.
  • You are dealing with high temperatures - the hotend gets hot, and may be off your printer when you do the initial tightening. If you touch it, you will get burned!
  • You are dealing with high currents, make sure you double check all your wiring and your power supply rating.
  • This is high performance hotend, capable of reaching a wide range of temperatures. The temperatures that ignite some plastics are within the normal printing temperatures of other plastics. If you only plan on printing ABS, PLA, and/or Nylon, it is recommended that you set your heater cartridge “MAX_PWM” to 150 in your firmware, in order to limit the heater to a range suitable for these plastics. If you are not printing materials requiring ~300C, there is no need for “MAX_PWM" to be set over 150. This variable can usually be found in the configuration.h file of your printers firmware. You can always change it to a higher value when you want to experiment with higher temperatures.
  • Like all 3D printers, printers fitted with a high temperature all metal hotend can be a fire hazard. You are using experimental technology to heat and melt plastic, in a machine that you may have built or modified yourself, that likely does not have safety certification or significant failsafes. Fire/Smoke alarms, supervision of your printer while printing, and expertise should not be considered optional
  • Your hotend and your printer is your responsibility. We cannot be held responsible for damages caused by the use, misuse or abuse of our products.

Package contents

  • Pre-assembled V6 hotend (heatsink, heatbreak, heater block, nozzle, M3 screws, fan shroud, 30mm fan with 1 meter wiring, fan voltage 12V or 24V).
  • PTFE tube 4mm OD 2mm ID, 1 meter long.
  • PC4-M6 tube fitting.
  • Modular pre-assembled Semitec 104GT-2 thermistor with JST connector.
  • Thermistor cable.
  • Heater cartridge 40W, 12V or 24V.
  • 2.5mm Allen key.

Tools you will need

  • 16mm spanner or adjustable wrench
  • 7mm spanner or adjustable wrench

Assembly Step 1

You need to disassemble hotend - remove nozzle and heater block, as pictured. Screw nozzle into the heater block into the end closest to the thermistor holes. Unscrew the nozzle a 1/2 turn.

Assembly Step 2

Screw the heatbreak into the other side of the heater block so it is butts up against the nozzle.

Assembly Step 3

Gripping the heater block with a spanner, tighten the nozzle with a second spanner. Do not over-tighten, we are going to tighten it up later when the heater block is hot.

Assembly Step 4

Screw the heatsink onto the heatbreak by gripping the heatsink in one hand and the heater block in the other. It only needs to be tightened up hand-tight. Do not overtighten.

Assembly Step 5

Place the of the thermistor into the hole, and fasten in place using the smaller M3x4 screw and washer. Use your fingernails to keep the sleeving under the washer whilst tightening. Visually check that the white 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.

Assembly Step 6

Install and tighten heater cartridge. You can skip this step if cartridge was already tightened in heater block.

Assembly Step 7

Snap on fan with shroud, as pictured, then Insert PTFE Tubing

  • This step apply for both 1.75mm Direct and 1.75mm Bowden.
  • The PTFE tubing in the 1.75mm Direct configuration is not optional, 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.
  • the PTFE tube actually runs through the heatsink and into the heatbreak, please ensure the tubing as seated as deep into the hotend as possible.

PTFE recommendations

  • On bowden systems it is especially helpful to 'lock in' the PTFE tubing so that it cannot move around during retraction, this increases reliability, and gives much better retraction performance in general. To do this, push the PTFE firmly into the hotend, while pulling upwards on the black collet that retains the tubing. This locks the tubing into place so that it cannot move during retraction. It is important to do this at both ends of the tube.
  • To release the tubing from the heatsink simply press down on the black or grey collet in the top of heatsink while pulling on the tubing.
  • In 1.75mm Direct configurations thought should be given to running the PTFE right up as close to the hobbed bolt/drive gear as possible as this provides the easiest loading and the best performance with all filament types. However if you do not wish to run PTFE up to the hobbed bolt or drive gear you can simply cut the tubing off flush with the top of the hotend.
  • Shown below is a cutaway illustration of how an optimal PTFE configuration might look in a wades type extruder. The PTFE tubing extends right up to the hobbed bolt.

Firmware configuration

In the following stages we are going to configure the hotend in firmware then go on to do the final hot-tighten of the hotend. This can be done either on or off your printer, however where practical we recommend doing it off your printer, then mounting.

Connect the heater-cartridge and thermistor to your electronics board. Please refer to the documentation specific to your electronics for pin-outs and other technical information which may be relevant to the hotend installation.

Marlin

Reconfigure your firmware for the Semitec 104GT2 thermistor: In configuration.h:

  • #define TEMP_SENSOR_0 5

For safety it is strongly recommended to do the following:

  • Set the minimum temperature to detect bad wiring (HEATER_0_MINTEMP 5 in configuration.h)

In newer versions of Marlin there are extra features for Thermal Runaway Protection should your thermistor come loose.

Upload the new firmware to your electronics.

Repetier

Use thermistor definition number 8:

  • #define EXT0_TEMPSENSOR_TYPE 8

Or select "ATC Semitec 104-GT2" if using the Online Configuration Tool (v091)

For safety it is strongly recommended to do the following:

  • Set the Minimum defect temperature to ensure that the thermistor shorting out is caught by the firmware.

New in Online Configuration Tool (v092) are the two options to also improve safety:

  • Decouple hold variance and Decouple min temp. rise to detect the thermistor coming loose. These must be set appropriately for your system to ensure that they work properly.

Upload the new firmware to your electronics.

Smoothieware

Use thermistor definition “Semitec”:

  • temperature_control.hotend.thermistor Semitec

Upload the new firmware to your electronics.

RepRapFirmware

Use the Beta value 4267K.​

Upload the new firmware to your electronics.

PID Tunning

  • Connect hotend to the printer electronics
  • Run M303 to autotune your PID - check out Thomas Sanladerer's video guide for more information. Please note that not all firmwares support autotune, and you may need to tune manually.
  • Set the HotEnd temperature to 285ºC. If you did not do a PID tune, then approach this temperature slowly, exceeding 295ºC will permanently damage the thermistor.

Final Tightening

When the HotEnd is at tempereature, tighten the nozzle whilst holding the heater block with a spanner. This will tighten the nozzle against the HeatBreak and ensure that your hotend does not leak. You want to aim for 3Nm of torque on the hot nozzle - this is about as much pressure as you can apply with one finger on a small spanner. The nozzle does not need to be torqued down incredibly tightly to form a good seal, when at lower temperatures the aluminium will contract and hold the Nozzle and heatbreak together.