An unoriginal prusa enclosure

My new mk4 deserved a fresh home! Here are the key features:

• A solidly built, minimalist enclosure with aluminum extrusion frame and large acrylic windows all around (sizing slightly larger than the original prusa enclosure)
• Front door is fully removable but attached with strong hidden magnets
• Entire enclosure frame can be easily lifted away from the printer, giving easy maintenance access.
• Enclosure frame slides onto alignment pins to get it back at the exact same spot as before
• Cable passthroughs to mount power supply mount underneath the table
• An easily adjustable, print-in-place vent on top to get the internal temperature just right.
• Acrylic drilling can be fairly imprecise- built-in parts are made to cover every drilled/machined hole

General build tips:

• No supports required on any print, unless otherwise stated. 
• All parts printed at 0.2 mm layer height (can probably get away with 0.3mm for all components except the vent and front door handles)
• All parts printed at 15-20% cubic infill, except top handle (see assembly instructions)
• All parts printed with Overture black/white PLA (though I may redo it in PETG in the future if I get into higher temperature filaments. Recommended color included in filenames. 
  • The frame acts as a huge heatsink, shedding heat effectively from functional components
• This is not an airtight enclosure! Mostly to keep out cats, stabilize from drafts, and control ambient temperature a little better. As a result, I planned to have 1/8 inch gaps along the sides and top of each acrylic panel.

Enclosure Assembly:

1. Assemble the big ikea lack table: it's just the right size for prusa enclosure sizing. Don't build in the lower shelf if you want to leave a filament dry box underneath
2. Buy EX-1515-BLACK aluminum extrusion from tnutz
   1. 6x 21 inch pieces (these will be the legs (z axis relative to printer) and horizontal bars (x axis relative to printer)
   2. 2x 25 inch pieces (these will be along the y axis relative to printer)
   3. Also buy 70x M8x16mm button-head screws and 70x 15-series standard M8 t-nuts
      • You can potentially substitute these screws/nuts for generic parts, but I wanted to splurge on this enclosure
3. Assemble the aluminum extrusion frame (see photos for the right orientation):
   1. Print all parts in the frame skeleton folder below. No special treatment needed for any parts other than the top handle
      • Top handle printed at 0.2 mm layer height, 50% gyroid infill with 5 walls to make sure it can hold the whole weight of the printer. The enclosure is heavy from the aluminum, don't skimp on this. Also, supports can help with this part.
   2. Take two 21 inch extrusions and orient them along the z-axis. Now put the 25 inch extrusion sitting on top (call that the y axis) so you can see the 25 inch extrusion's end but not the 21 inch one. 
      1. Screw them in place with 1x top joint side1 and 1x top joint side2, so that the slots lie along the y-axis 
      2. Repeat the step again with 2x 21 inch and 1x 25 inch extrusion. You should have two sets of legs now.
   3. Slide two t-nuts into each y-axis to hold the top braces for later. Refer to images to see which side.
   4. Take the two remaining pieces of 21 inch aluminum extrusion. This will be the x-axis
      1. Slide two t-nuts into the x-axis so that all nuts will sit along the same slot. 
      2. Screw the two pieces of 21 inch extrusion into the 25 inch y axis. When done with this, the only visible ends of aluminum extrusion will be the 25 inch extrusion and the four legs.
   5. Slide on the feet of the extrusion and screw in. Two of the feet will be identical - these go in the back. The front two feet will have magnet holes facing the front, and the front two joints will be the top joint magnet braces.
   6. Screw in the top braces into the t-nuts you placed earlier. You should have two braces for each extrusion along the top.
   7. Sanity check the build: all the magnet holes should face the front. There should be four top braces mounted in 
4. Acrylic mounting:
   1. Buy 1/8 inch extruded acrylic. I got these cheap from a local plastics store (TAP plastics if you're in the bay)
      1. 2x front/back pieces 20 3/4 x 21 7/8
      2. 2x sides: 22 1/4 x 21 7/8
      3. 1x top: 22 1/4 x 20 3/4
   2. Cut a 5mm x 45mm rectangle out from the sides of each sheet. I just did this with a dremel drill bit and essentially melted away the plastic. This will make room for the feet (some day I'll modify the design to accommodate uncut acrylic)
   3. Print all parts in the “frame acrylic mounting” folder. 
   4. Mounting side and top panels:
      1. Plan to have the acrylic resting on the table, ie not suspended in the air by screws. I found that to give a cleaner look.
      2. Drill ~4mm holes in the acrylic corresponding to the locations of the slots. Note that the frame mounting system is entirely clamping between two pieces of plastic, so there's room for error in all drilling steps.
      3. Drill a single 182mm hole in the center of the top panel for the vent
      4. Use M4-0.7 x 20mm socket head cap screws and M4-0.7 hex nuts to assemble. You will need 16 screws and 16 nuts. Use the acrylic mount printed parts to essentially clamp in the screw.
   5. Mounting front panel:
      1. Pull an M3 hex nut into each front door handle base, then once you're sure it's secure push a 10x10mm magnet (same as above) into the base. 
         1. Make sure that the magnet orientations will match the frame. You can use a marker to mark which sides need to face outwards.
      2. Drill holes in the front panel corresponding to the thickness of the front door handle base, then push that through the holes.
      3. Put the front door handle cap on top and screw it in, clamping the assembly around the acrylic in the process
5. Cable passthrough and PSU holder
   1. Print all parts in “Table passthroughs & PSU bracket”
   2. Mounting pins:
      1. Put the enclosure on the lack table and decide where it'll be mounted. Mark it off, then put double sided sticky tape on the foot pins to get them attached to the feet of the enclosure. 
      2. Place the enclosure at the decided spot and then lift, leaving behind the foot pins. Screw them in place gently with wood screws, taking care to not strip the hole. (I used #8 flat head philips wood screws from home depot). 
         1. Then remove the screws, remove sticky tape, and screw in snugly
   3. Cable passthrough:
      1. Place the printer in the enclosure and check for placement. Mark off the corners when satisfied (my mk4 fits well ~1.5-2 inches from the front
      2. Decide where to place the cable passthrough. I put mine to the front left of the y axis motor, ie on the xbuddy board side). That spot is nice because it leaves a lot of slack for cables and if you decide to move the printer side to side nothing will really sit on top of the passthrough.
      3. Drill through with a 1 3/8 inch drill bit, cutting the hexagonal paper material with scissors halfway through.
      4. Screw on the cable passthrough lower section to lock it in place
   4. PSU holder
      1. Put the PSU with connectors just adjacent to the passthrough
      2. Place two M3 hex nuts in the PSU bracket with the pull-through technique. Screw it in place underneath the table. with #8 flat head philips screws.
      3. Test-run the placement of the PSU, then mark off where the PSU holder should go.
      4. Remove the PSU, then screw in the PSU holder. 
      5. Secure the PSU to the bracket with M3 screws.
6. Top vent
   1. Print vent outer case, making sure the outer side (with flat slats) is on the bed. 
      1. It's important to print this at 0.2mm layer height with no supports: all parts support each other with a 0.2mm gap between them, so it's effectively all internally supported.
      2. Once printed, gently shift around the slats to break them free for turning. Note that the pins are just long enough to remove a slat if necessary.
   2. Print vent inner case and rib, then screw the rib into the slats via 5x M3x16 screws
   3. Press 8x3mm magnets into the holes if desired. These will help lock the slats shut but aren't necessary.
   4. Screw vent into the top hole. Be very careful screwing these, the parts are robust enough to work just fine, but the walls aren't extremely thick. 
      1. I chose to screw it in so that the slats open away from the front. That way it covers all the internal machinery when opening.
7. Dry box & filament management
   1. ***Instructions & models below are incomplete! Will delete this line when instructions are good. The current system works, but I'm currently unhappy with the lack filament passthrough.***
   2. Print all parts in Drybox and Filament Management folder. Note: some parts have particular printing conditions, check the file notes for each before printing.
   3. Dry box:
      1. Buy:
         1. 45L ikea samla box (perfect for 5 standard spools)
         2. 3.6-7.5 lbs orange indicator silica gel (pictures above are of 7.5 lbs of silica gel in the box)
         3. 2x M8 x 500 mm, 1.25mm pitch threaded rods
         4. 24x M8 hex nuts, 1.25 mm pitch
         5. 20x 608zz bearings (I'm semi-happy with the linked brand, 1 of them was imperfectly manufactured. It's cheap and pretty much fine.)
      2. Screw the drybox supports into the corners of the dry box using M3 screws. I marked holes and pre-drilled with a thin drill bit.
      3. Press bearings into the drybox bearing_track parts
         1. Stack the following, bottom to top: bearing, bearing_track, a hardcover book
         2. Clamp the stack shut with a vice (or if you don't have that, sit on the stack). 
            1. Note that I designed the bearing_track to have ID 21.9mm, 0.1 mm smaller than the OD of the 608zz bearing. If your printer isn't fully dialed in, you may need to scale the bearing_track size to 100.5%.
         3. Now, make a new stack, bottom to top: bearing insert helper, the semi-inserted bearing, and a hardcover book. Clamp this shut as before, thus pushing the bearing to the correct position
      4. Assemble the threaded rods with bearings in the correct position for your spools. For all adjacent spools, separate bearings with one drybox washer so they don't rub against each other.
      5. Place threaded rods into samla box with drybox supports in place
      6. Pour in silica gel as desired. It may help to have a spool in place to see what level you want the gel to be at
         1. I intentionally wanted the silica gel to be loose in this build. I wanted to maximize the dehumidification of the environment, and I thought that it would be best to have a very large surface area directly exposed to the air.
   4. Filament management:
      1. Buy XXXXXX
      2. Screw pneumatic fittings into PTFE drybox adapters. It may be helpful to screw with two wrenches at the same time.
      3. Drill ½ inch holes into the dry box at desired positions and screw in the PTFE drybox adapters. 
         1. I mounted my adapters ~3-4cm higher than the height of the threaded rods. This lets filament pass cleanly from both a full spool and an empty one.
      4. PTFE harness:
         1. Note: the filament management system accommodates six PTFE tubes: 5 for the MMU3 and 1 extra for special filaments that may need to have a custom path or storage system (e.g. printing directly out of a filament dryer). For the build below, use the harness slots 1-5.
         2. Press fit 10mm x 10mm cylinder magnets (link above) into PTFE harness with opposite polarity. (ie north pole faces up in one side and down in the other side). This will prevent the user from plugging in the harness the wrong direction
         3. Press fit 8mm x 3mm cylinder magnets (link above) into the other side of the PTFE harness with polarity matching the other side of the harness.
         4. Sanity check: the harness should attract strongly in one orientation but repel in the other. The embossed numbering doesn't matter yet.
         5. Screw in pneumatic fittings to both sides of the harness
         6. Connect dry box to PTFE harness: connect dry box to the side with small magnets/embossed numbering. The side with large magnets will connect to the lack filament passthrough.
      5. Lack filament passthrough:
         1. Trace position of filament passthrough and drill two ½ inch holes at ends to start the cut. Cut a slot between those holes. You can clean the cut edges nicely with a dremel tool rotary sanding attachment.
         2. Try to keep the drill as straight as possible and continue the ½ inch drill through to the bottom of the table
         3. Attempt to mount the filament passthrough. Try to get the top part to be an exact fit. 
            1. While drilling, if the drill wasn't straight, the screw holes won't line up well with the lower part. I designed the lower part to accommodate inaccuracies in this alignment: you can widen the lower slot up to 1 inch diameter without any issue in mounting.
         4. Screw in place with M3 screws. Note that the lower table component has right to left numbering, corresponding to the MMU3 numbering order.
            1. I added some M3 screws in the top part for aesthetic, but the screw holes are there in case I wanted to build an attachment to mount to this part.
         5. Connect PTFE tubes to the printer side of the PTFE harness and thread them through the lack filament passthrough. You're best off cutting the exact amount of PTFE tube needed; otherwise the printer will pull the filament and PTFE tube together.
      6. Filament guide (if no MMU or if direct loading through PTFE tube 0):
         1. Design should be printable in place, but it requires fairly tight tolerances and good bed adhesion. It's a fast print at 0.2 mm quality prusa settings, so I'd just try to see if it works. If printing on prusa machines, print with the part oriented along the y-axis, as that has better printing. All prototypes printed flawlessly on the mk4 with these settings. Consider adding brims if there is bad bed adhesion, but do not print with supports!
         2. Turn the neck until it moves freely. Shouldn't take much force. Rotate the neck several times until it turns smoothly.
         3. Insert 608zz bearing into position. This may take a good amount of force (consider placing the bearing on a sturdy table and pushing the filament guide onto it). Tolerances are tight on the bearing to prevent any slipping mid-print.
         4. Insert M3 hex nut into bottom hole, and pass M3 x 12 mm screw through the nut. Clamp whole assembly onto the prusa frame. Note that the screw needs to clamp just hard enough to prevent the guide from slipping off the frame.

Upcoming additions:

• Neater/lower friction cable passthrough design with bearings to prevent PTFE tight turn radius issues.
• Lower filament cost PSU holder

Very open to feedback, and if it aligns with my interests I'm happy to upgrade parts!