The Carbon Aktivist - 5015 VOC Activated Carbon Filter

The Carbon Aktivist - activated carbon VOC and odour filter

EDIT - Top tip … I also use one of these as an air filter when I'm soldering 

Attach or place in or near any 3D printer or enclosure in order to help keep you healthy and clean the nasty stuff from the air caused by your prints. 

• Small form factor 
• Universal mounting options for enclosures - open or enclosed (better)
• Activated carbon air purifier / filter 
• Looks good 
• Easy to print
• AND most importantly … keeps your print environment healthier!

If the science is to be believed activated carbon will not only help stop nasty odours but also potentially harmful VOCs (Volatile Organic Compounds) generated from 3D printing and which are known to cause severe health issues and may even be cancerous!?!

Design concepts

• After a little investigating I decided that re-circulating rather than venting the air within my (sealed) enclosure would mean repeat passes of the pollutants / odours through the carbon should give it more chance to adsorb more unwanted particles. 
  • Can be used in open environments, and / or maybe even double up - one on each side of the print head / printer to double the amount of filtering
• Quick + simple to print
  • I wanted to get this in place and test effectiveness fast
  • didn't want a massive shopping list of parts or a big complicated project (nevermore looks awesome however perhaps a little overengineered for my needs, at least right now)
• Minimal use of commonly found bolt sizes and heat inserts (4 x m3)
  • 4x short m3 bolts (choose 8mm, 10mm 12mm or longer) 
  • 4x m3 heat inserts
• Small form factor so it can be placed close to hotend or wherever best
• Re-usable ofc
• 5015 blower fan 
  • with top cowl removed - not simply for aesthetics, should give increased / wider airflow
  • Screw-less mounting to minimise hardware needs
  • don't forget an exit path for fan cable!
• Simple yet optimised airflow (without getting too sciencey) 
  • add channels and position exit ports to attempt even airflow over activated carbon
• Alternative mounting options
  • place close to the print head or in bottom of enclosure on adhesive rubber pads or similar
  • optional - 2nd base stl file included here has open holes all way through base for more heat inserts and so mount securely on enclosure, frames  alu profile with t-nuts or other surface (again sized for m3 heat inserts to keep bom simple)

Print

• nothing special, no supports required … did mine fast at 0.24 with 0.28 first layer 30% adaptive infill, pretty quick print speeds and it turned out nice n clean

Assembly

• print 
• decide on mounting and melt heat inserts into place  … hints: 
  • if sitting flat or on side or similar - print standard “5015 carbon aktivist mk1_21 base.stl” (the holes do not extend through the base)
  • if you're wishing to use t-nuts or other 3mm bolts and attach them into the bottom of the filter
    • print "5015 carbon aktivist mk1_22 base #2.stl" with mount holes all the way through the base so you can add more heat inserts as necessary
  • if you're unsure - print the second option
    • its harder to locate holes and drill through the base once the top heat inserts are in place. 
• cut side tabs off the 5015 blower fan - top cowl then easily comes off
  • clean / clip any other tabs or bits on the sides off the fan that may be sticking out and so stop it fitting into the case
• put 5015 fan in case 
  • could be a tight fit, I've increased tolerances since my v1.0 to help here
  • make sure it slots in flush to base of the case 
  • ensure the cable comes out of the side slot
  • If for any reason it's a bit loose, maybe a blob of hot glue to secure, but remember the top cover also holds it in place with fairly tight tolerances
• add activated carbon pellets or similar (designed for ~3mm diameter type)
  • replace carbon based on usage - I am still testing
  • You will need to source these locally yourself
• screw lid into place with whatever m3 bolts you prefer or have the most of 
  • should work with 8, 10, 12mm … or longer if you are struggling
• Final part - attach to fan header or attach a power source
  • spare fan header on mainboard
  • splice into existing cabling
  • or … however you wish to power and control it

Klipper config

If like me you're running klipper with an aftermarket mainboard, then you can perhaps connect this its own fan header 

• klipper config suggestion: the filter fan comes on when the hotend heats above 50ºC and switches off when it drops below … so it continues filtering for some time after print has finished. 

Example: add/amend as below accordingly in Printer.cfg  

[heater_fan carbon_aktivist] # carbon filter  
pin: PD13         # change to match connection to your mainboard 
max_power: 1.0
shutdown_speed: 0 # if printer fault fan goes off - set 1 to keep on
heater: extruder  # linked printer part - when "extruder" heats fan starts
heater_temp: 50.0 # filter fan will only start / stop above
fan_speed: 1.0    # fan speed when on, 1.0 = 100% ... 0.5 = 50% and so on

… and now …. you can breathe a little more easy 😬

Feel free to donate via Paypal if you appreciate my efforts and would like to help keep me in filament and publishing designs :)