Lack Enclosure HEPA Filter System

This design is a build off my initial fan/filter design. Once I saw how much dust was coming off the printer, I decided to upgrade to a proper HEPA filter.

This design is a touch over engineered since I was working with some specific constraints.

• I wanted to use the same hole and sleeve I had already cut into my Lack enclosure from the previous design.
• I wanted to use the same brand fan so I could use the variable speed control.
• I wanted to use a specific HEPA filter.

Notes

• If you did my previous design, you can print and adapt this one right in without any modifications to your current enclosure.
• The fan I used here is louder than the one I used in the previous design. I didn't care about noise, I care about filtration.
• On top of the HEPA filter, which has its own built in carbon pad, I added two more pre-filter carbon pads.
• I printed this in PETG, but no reason you can't do it in PLA. Nothing is really structural.

Here are the parts you need to purchase, note this is assuming you did not do the previous design.

• 120mm AC Fan - 110 CFM - https://www.amazon.com/gp/product/B009OWRMZ6/ref=ppx_yo_dt_b_asin_title_o00__o00_s00?ie=UTF8&psc=1
• OPTIONAL - Variable speed control for fan - https://www.amazon.com/gp/product/B00809BQZG/ref=ppx_yo_dt_b_asin_title_o03__o00_s02?ie=UTF8&psc=1
• Cut to fit Carbon pre-filter pad - https://www.amazon.com/gp/product/B074MKZNFW/ref=ppx_yo_dt_b_asin_title_o03__o00_s01?ie=UTF8&psc=1
• HEPA Filter (2 Pack) - https://www.amazon.com/gp/product/B074T4KJ2C/ref=ppx_yo_dt_b_asin_title_o02__o00_s01?ie=UTF8&psc=1

• Molex power connectors : https://www.amazon.com/gp/product/B07CVZPTN4/ref=oh_aui_detailpage_o02_s02?ie=UTF8&psc=1

• Print all pieces (Note, you need two of the pre-filter spacers)

Enclosure Modification & Install
(First time install only, if using previous design you can skip)

• Cut hole in lack table the same size as the sleeve, this piece goes in from the underside of the table and will be flush with the top. I used hot glue on the flange and that was more than enough to secure it to the table.
• NOTE - Make sure you place the notch in the sleeve in the same direction you plan to run the wire to the leg. That notch is for the cable.
• To run the wire to the fan, you can easily drill a hole through the top of the leg, the printed corner piece, and the underside of the table as the legs are hollow. The inside of the table is paper, so easy to push through. See the attached picture of how I completed this.
• I did have to cut the wire to run it and added a molex connector to it so I could also disconnect the fan later if needed. Note the notch in the top of the lack table, this is to get the bezel past the wire.
• The wire runs down the leg and there is an additional molex connector for when I need to remove the top of the enclosure.

Assemble Filter

• Glue Bezel Coupler to the inside of the Bezel. You can use your favorite glue of choice, expoy, CVA, or Hot Glue.
• Glue lower filter housing to the coupler you just glued into the bezel piece.
• Install fan into upper fan housing, using screws that come with it. You will have to trim the screws.
• Insert alignment pegs into upper fan housing. This will help line up the upper and lower pieces.
• I used hot glue to attach the upper and lower fan housing pieces together. That way if I ever need to get the fan out, a heat gun will loosen it enough to pull it apart. Yet, it will keep a nice air seal.
• Insert HEPA filter into lower filter housing. Note the notices in the sides of the housing match up to the notches on the HEPA filter itself. This is to lock it in place and to make sure it is installed in the right direction.
• Slide the fan assembly over the lower filter assembly.
• For the power wire, this is up to you. In my case, I used a molex connector on the other side of the bezel that connects to the lead wire molex connector. This way it was cleaN and all inside the table. The fan wire disconnects at the fan as well, so you have two ends you can connect/disconnect it from. If you have questions here, let me know.

Carbon Pre-Filter

• Cut two pieces of the carbon filter to the size of the sleeve that is installed in the Lack enclosure.
  
• Place the first piece inside the sleeve
• Place in the first pre-filter spacer
• Place the second pad in.
• Place the second space on top of that pad.

These spaces will lock in place once the fan assembly is inserted. They also keep the pads flat and uniform under the air pressures. I notice these get debris in them pretty quick, so they should be changed often.

If you have any questions, please let me know!