Introduction: 3D Printable Solder Fume Extractor / Air Filter: the Two Towers

Intro:

In the past, while soldering, I used a large fan to move the fumes away from me and keep my workspace (and nose) clear. It created a bit of a strong breeze, but, for the most part, it kept my breathing air clear.

Next, I tried a 3D printer-built small portable battery-operated fan with an adjustable stand. It worked well and could be turned on and off without getting out of my seat, very important, but it needed to be close and took up a bit too much of my work space.

Neither solution was great, as was pointed out repeatedly, as I was just dispersing the fumes rather than filtering out any of the impurities.

Background on Solder Fumes

Whether the issue is the fume produced by the flux (rosin core solder) or the lead content of the solder itself, it is recommended that suitable and sufficient ventilation be active when working with rosin based solder.

Rosin-based solder flux fume is a contributing cause in many cases of occupational asthma. It is thought by most to be as dangerous during soldering as the Lead itself. It affects many workers in the electronics and assembly industries.

When heated at above 180C, well below normal soldering temperatures, it vaporizes and condenses into fine particles, which form the fume which is usually seen as a white smoke. The higher the temperature, the more fume is generated. The lead free solders introduced have higher melting points than the traditional lead/tin, lead/silver types, but, ironically, the elimination of lead has led to a potential for increased exposures to asthma causing fumes.

The Fume Extractor

The average fume extractor works by using an activated carbon or HEPA filter and a medium-to-high power fan to remove soldering particulate and other poisonous fumes from the work area. The costs for a commercially available hobby-model can be as much as $150, but a low-cost somewhat usable solution can be made using relatively low-cost parts, depending on what features and level of filtering are required.

Fan rating (CFM)

A fan's ability to move air is measured in cubic feet per minute (CFM). It is a measurement of the velocity at which air flows into or out of a space.

CFM is also a key factor when determining a fan’s airflow efficiency. Airflow efficiency is the CFM divided by the watts/amount of energy used to run the fan. As I am only looking to use the fan for short-periods, during my active soldering, the efficiency is not a major concern, but I certainly wouldn’t mind high CFM at a low wattage.

Goals


So together with the background above, the goals of this project:

1- Create a filtered Fume Extractor using existing Fans

Fairly light weight and taking as little of my usable work space as is feasible.

2- Powerful enough for reasonable distance operation

The fan(s) should have a high enough CFM rating rating to be functional and remove fumes and

particulate.

3- Easily changeable orientation and height

I should be able to move the fans around my work space without too much space loss

4- Easily modifiable with exchangeable component parts

Electronic components, Fan(s), and carbon filter should be accessible and easily replaced. The device design itself should be modifiable simply by replacing parts with modified versions that snap in.

5- Battery and/or DC adapter powered

The unit should operate on either battery or AC/DC adapter as required

6- On/Off switch

Unit should have an ON/OFF switch so I don’t have to get up.

7- LED indicator

LED should indicate visually when the fan is on. (Remind me to shut it off when not using it)

8- Support various input voltages from (~3.7V DC to 30V DC)

Should support any input voltage in the range above with no effect on the fan speed.

9- Most parts should be 3D printable with the STLs available to print/modify as required

All base, brackets, electronics case, fan and carbon filter holders should be 3D printable and all models available.

Step 1: Components

Picture of Components

3D Printed Parts

The STL's for all 3D printable parts can be downloaded at:

https://www.thingiverse.com/thing:2574252

The List below includes the parts to build a two fan tower. It is easy to expand to more fans by printing and using more Mitte and Dowels:

  1. Tower Top/Bottom Pieces (2)
  2. Tower Mitte Pieces (2)
  3. Long Dowels (4)
  4. Short Dowels (2)

The Electronics Case requires the following printed parts

  1. Electronics Enclosure Box and Back Panel (1 each)

Electronics

Listed by Column:

  1. (4) Male pins (to attach XL6009)
  2. (1) 5*7 Double-sided PCB
  3. (3) 2 pole 5.08mm Pitch PCB Mount Screw Terminal Block 10A
  4. (1) DC-DC Boost Buck ADJ Step Up-Down Converter Module Solar Voltage XL6009
  5. (1) 2 Pin ON / OFF IO SPST Snap-in Mini Boat Rocker 250V 3A
  6. (1) DC Socket 3A with Nut
  7. (1) 2-3 V LED
  8. (1) 680-820 Ohm 1 Watt Resistor

Fan and Filter

  1. (4) Artic F8 80x80x25 mm 12V Fan
    • Fan Speed: 2,000 RPM (@ 12V DC)
    • Current12V: 0.16A
    • Air Flow: 31 CFM / 52.7 m³/h (@ 2,000 RPM)
  2. (2) Carbon Filter

Step 2: The Circuit

Picture of The Circuit

The DC-DC Boost Buck ADJ Converter Module Solar Voltage (XL6009) is an Automatic Buck-Boost module that takes an input voltage between 3.7 and 32V and produces an output that is continuously adjustable between 1.2 and 35V.

For this project, I used a multi-meter and adjusted the output to 12.5 V.

The maximum output current is 1.5A so you must pay attention to the total amperage drawn by the fans connected in parallel as well as by the XL6009 itself. This is not a problem for the draw above and even a 3.7V LiPo will be fine with the 4 160 mA drawing fans.

The input voltage comes from the adapter connector or battery and the available current should be well above the expected draw. I have used both a 12V /1.7 A adapter and a 3.7V 5000 mAh LiPo.

The 820 Ohm - 1W resistor is connected to the positive lead of the LED (CN2) (680 Ohm would be fine as well, but I wouldn't go below that and stay with a 1 Watt variety to keep the heat down.)

The other connectors, CN3 and CN4 are both parallel connectors for the fans. I connect 2 fans to each connector in this usage.

If no voltage conversion is required, either higher or lower, then the XL6009 is not needed and you could drop it. This would be the case if you wanted to run off a 12V Adapter and nothing else.

When you assemble the basic board, it will need to be cut down a bit to fit in the control box.

Step 3: Assemble the Control Box

Picture of Assemble the Control Box

Glue in the LED

I soldered a couple of wires to the LED leads and then used some crazy glue to set it. I let it dry before testing with low voltage and Milliamperes.


Led test

Rocker Switch

I soldered a couple of wires to the ROCKER Switch and then began to assemble the Control Box

Attach Socket to Control Box Back and Solder Wire

I soldered a single wire to the ground connection of the DC Socket


Attach Socket Rocker Switch and Solder Wire

Solder one wire from the Rocker Switch to the positive lead of the DC adapter socket, it doesn't matter which Rocker switch wire.


Wire up the Circuit Board

  1. Other Wire from Rocker Switcht to Positive input on CN1
  2. Other wire from AC Adapter to Negative input on CN1
  3. Positive wire from LED to Positive input on CN2
  4. Ground wire from LED to Negative input on CN2
  5. For the fans I combined the positive wires from two fans and then the ground wires from the same two fans. I then wired them to CN3. Rinse and repeat for fans 3 and 4 if you are using four fans and wire up to CN4.


Closeup the Box with a couple of Screws and Give it a Test

The holes are 3 mm. Here you will have to shave a bit off the 5*7 board to fit inside the control box, see picture above.



Step 4: Size a Couple of Filters and Cut

Step 5: Assemble the Tower and Test

Just a word of warning, the build video uses AVC 12V .5 Amp fans. These are almost 3 times as powerful as the F8s used earlier and are much louder.. Cheers..

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