Let's build a VORON Trident

Let's build a VORON: Filters

Published: December 15, 2023 in 8da5c32

This is part 7 of the Let's build a VORON Trident series.

I can print, but the printer is missing a very important thing that I alluded to in the previous post: filtering dangerous particles and fumes.

This is mostly covered by the kit, but I was missing some parts from the print it forward and the kit didn’t include a HEPA filter. Because the printer is in the office and health is super important fixing this was needed so I could start printing some ABS and continue modding the printer.

Exhaust cover

The standard VORON comes with a filter in the back, but the LDO kit doesn’t include the fan for the filter and instead uses an exhaust cover to close the hole.

I didn’t receive this part, so the first thing I did was to print that part. This was just a very temporary measure so I printed it in PLA.

Nevermore filter

The LDO kit includes the Nevermore filter, which removes VOCs. I was confused on how to install it as at the time the LDO docs only mentioned how to install it on a 2.4, not on a Trident. When I brought it up they fixed it so no big deal.

But they wanted me to mount it using a plenum mount, which my parts didn’t have. I think I received an older version of the Nevermore from the print it forward service so I couldn’t use it.

I instead printed out the updated plenum and frame connector myself. Because the point of the Nevermore is to be able to print ABS safely I did this in PLA as well. I know it’s not ideal, but it will have to do. Lazy as I am I’ll run with this and if it breaks I’ll replace it then.

I also added some strips of foam tape to the back of the filter to prevent it from scrambling against the back panel.

Cutting away parts from the fans was horrible. They broke very easily.

I finally got to exercise my (very poor) soldering skills! It was cute how LDO included a small board so that you don’t have to crimp any cables.

HEPA exhaust filter

A new HEPA filter. I wasn’t able to color match with the print-it-forward parts…

While I have the Nevermore filter, it doesn’t filter Ultra-Fine Particulates. For that you need a HEPA filter.

There were a few solutions with combined carbon and HEPA filter, but since I already have the Nevermore I wanted a standalone HEPA filter. I found the Voron HEPA Exhaust Filter that replaces the stock filter that seemed like a good option.

With the Nevermore in place I could print the parts using ABS, and they turned out pretty well.

For silence I used a Noctua FN-A6x25 fan. In hindsight I maybe should’ve used the PWM variant, if only to make the wiring simpler. Now I have this ugly looking wiring in the top corner (it uses the Noctua low-noise adapter).

I also had to create another cable, which wasn’t too difficult:

Converted the 3-pin cable to a 2-pin JST connector and extended it.

I simply ignored the yellow RPM speed signal cable.
Connect to a free fan output on the Octopus.
Used the 12V selection jumper for the fan output.

Klipper setup

With the fans installed you also need to configure Klipper to utilize them.

I setup them both as generic fans, so I can control them from the start and end macros:

[fan_generic nevermore_fan]
##  Nevermore fan - FAN3
pin: PD13
max_power: 1.0
kick_start_time: 5.0

[fan_generic filter_fan]
##  HEPA filter fan - FAN4
pin: PD14
max_power: 1.0
kick_start_time: 5.0

Then in PRINT_START I turn on the fans:

SET_FAN_SPEED FAN=nevermore_fan SPEED=1
SET_FAN_SPEED FAN=filter_fan SPEED=1

After the print has finished I don’t want to just turn off the fans immediately, but have them run a bit after the print has finished to clear out any toxic fumes. I accomplished this with a delayed_gcode:

[delayed_gcode _VENT_OFF]
gcode:
  SET_DISPLAY_TEXT MSG="Venting done"
  SET_FAN_SPEED FAN=nevermore_fan SPEED=0
  SET_FAN_SPEED FAN=filter_fan SPEED=0

That I call in PRINT_END with a timeout:

# Turn off fans after 30 min
UPDATE_DELAYED_GCODE ID=_VENT_OFF DURATION=1800

To prevent the fans from turning off mid-print if I get impatient and start a new print before _VENT_OFF has been called I also clear the delayed gcode in PRINT_START:

# Prevent Nevermore and filter fan from being turned off mid print
UPDATE_DELAYED_GCODE ID=_VENT_OFF DURATION=0

And now the filter fans turn on and off automatically.

Some people run the Nevermore on 50–80% during print and then go 100% at the end, but I don’t know why you can’t run it at 100% all the time so that’s what I do.

Reworked `PRINT_START`/`PRINT_END`

I also rewrote the PRINT_START and PRINT_END macros to make a little more sense to me. Here they are in their entirety:

[gcode_macro PRINT_START]
gcode:
  # Fetch data from slicer
  {% set target_bed = params.BED|int %}
  {% set target_extruder = params.EXTRUDER|int %}
  {% set target_chamber = params.CHAMBER|default(0)|int %}

  # Set temps for bed and extruder without waiting to save some time
  SET_DISPLAY_TEXT MSG="Preheating"
  SET_HEATER_TEMPERATURE HEATER=heater_bed TARGET={target_bed}
  SET_HEATER_TEMPERATURE HEATER=extruder TARGET=150

  SET_DISPLAY_TEXT MSG="Homing"
  G28                                                     # Full home (XYZ)
  G90                                                     # Absolute position
  G92 E0                                                  # Reset extruder

  BED_MESH_CLEAR                                          # Clears old saved bed mesh (if any)
  CLEAR_PAUSE                                             # Ensure that we can't accidentally resume an old pause
  # Prevent Nevermore and filter fan from being turned off mid print
  UPDATE_DELAYED_GCODE ID=_VENT_OFF DURATION=0

  SET_DISPLAY_TEXT MSG="Bed: {target_bed}c"
  # We're in the center of the bed after full home
  M190 S{target_bed}                                      # Sets the target temp for the bed

  # Heating nozzle to 150 degrees. This helps with getting a correct Z-home
  SET_DISPLAY_TEXT MSG="Hotend: 150c"
  M109 S150                                               # Heats the nozzle to 150c

  # Turn on fans to help with chamber heating
  SET_FAN_SPEED FAN=nevermore_fan SPEED=1
  M106 S255                                               # Turns on the PT-fan

  # Waits for chamber to reach desired temp
  SET_DISPLAY_TEXT MSG="Heatsoak: {target_chamber}c"
  TEMPERATURE_WAIT SENSOR="temperature_sensor chamber_temp" MINIMUM={target_chamber}

  # Only turn on filter after chamber has been heated
  SET_FAN_SPEED FAN=filter_fan SPEED=1

  SET_DISPLAY_TEXT MSG="Z-tilt adjust"
  Z_TILT_ADJUST                                           # Levels the buildplate via z_tilt_adjust
  G28 Z                                                   # Homes Z again after z_tilt_adjust

  SET_DISPLAY_TEXT MSG="Bed mesh"
  BED_MESH_CALIBRATE                                      # Starts bed mesh

  # Heats up the nozzle up to target via data from slicer
  SET_DISPLAY_TEXT MSG="Hotend: {target_extruder}c"
  SMART_PARK                                              # KAMP parking routine
  M107                                                    # Turns off partcooling fan
  M109 S{target_extruder}                                 # Heats the nozzle to printing temp

  SET_DISPLAY_TEXT MSG="Purge"
  VORON_PURGE                                             # KAMP purge
  G92 E0                                                  # Reset extruder
  SET_DISPLAY_TEXT MSG="Printer goes brr"

[gcode_macro PRINT_END]
gcode:
  # safe anti-stringing move coords
  {% set th = printer.toolhead %}
  {% set x_safe = th.position.x + 20 * (1 if th.axis_maximum.x - th.position.x > 20 else -1) %}
  {% set y_safe = th.position.y + 20 * (1 if th.axis_maximum.y - th.position.y > 20 else -1) %}
  {% set z_safe = [th.position.z + 2, th.axis_maximum.z]|min %}

  SAVE_GCODE_STATE NAME=STATE_PRINT_END

  SET_DISPLAY_TEXT MSG="Print done"

  M400                                                        # Wait for buffer to clear
  G92 E0                                                      # Zero the extruder
  G1 E-2.0 F3600                                              # Retract filament

  TURN_OFF_HEATERS

  G90                                                         # Absolute positioning
  G0 X{x_safe} Y{y_safe} Z{z_safe} F20000                     # Move nozzle to remove stringing
  G0 X{th.axis_maximum.x//2} Y{th.axis_maximum.y - 2} F3600   # Park nozzle at rear
  M107                                                        # Turn off partcooling fan

  # Turn off fans after 30 min
  UPDATE_DELAYED_GCODE ID=_VENT_OFF DURATION=1800

  BED_MESH_CLEAR
  RESTORE_GCODE_STATE NAME=STATE_PRINT_END

[delayed_gcode _VENT_OFF]
gcode:
  SET_DISPLAY_TEXT MSG="Venting done"
  SET_FAN_SPEED FAN=nevermore_fan SPEED=0
  SET_FAN_SPEED FAN=filter_fan SPEED=0