The Prusa i3 MK2S is a great printer especially for the hobbyist or light industrial desktop user. That having been said it is a raw printer without a lot of accessories that would make it a great printer. The is the second in a series of accessories that I designed for the i3. The others are:
Although Prusa i3 MK2S is a great printer, it lacks an enclosure that would isolate the print area from drafts and cold ambient temperatures. Enclosures are also necessary if you wish to filter the air before exhausting it into living spaces common for home 3D printers.
3D Printers produce VOC and Ultra Fine Particles as a unwanted byproducts of melting and extruding plastics. See recent study by Illinois Institute of Technology and The University of Texas at Austin among others: http://pubs.acs.org/doi/full/10.1021/acs.est.5b04983
The enclosure is constructed of 20x20mm aluminium extrusions, 1/2" finish plywood, and Plexiglass panels. The only 3D printed parts are the Extrusion End Caps and Filament Guide.
The basic frame is constructed from four 500mm & eight 600mm 20x20 aluminium extrusions joined at each corner by hidden "L" brackets. The picture below shows the placement of the extrusions at each corner. The horizontal front and back bars anchor the vertical and side bars. "L" brackets fit into the slots of the extrusion and fasten the 3 bars at each corner by tightening set screws built into the "L" brackets.
The 4 side to side extrusions are 500mm in length while the remaining 8 at 600mm.
This results in an interior space of 620mm Deep, 480mm Wide, and 540mm High. The width can be increased by 40mm by moving the front and back horizontal bars inside the side bars at the cost of 40mm in depth. In hind site this would have been a better configuration for the i3 since the power cable comes out of the side of the power supply, not the back. In the end I did not discover the problem until everything was assembled. It was easier to print a new power supply housing with the power cord connector in the rear rather than cut all new Plexiglas and plywood panels.
Add Plywood Top, Bottom, and Aft Panels
Once the Extrusion Frame has been constructed, carefully measure the top (or Bottom, they should be the same) and the rear dimensions. Cut the top and bottom panels 0.5" longer than the frame so that the aft plywood panel sits between the top and bottom panels. This hides the edge of the plywood panel which may include voids and other imperfections. See above.
Drill 2 5mm holes in each side of each panel 5mm from the edge (assuming you cut the panels to the exact dimension of the frame). Insert M5x20mm screws into each hole and start "T" nuts on each screw. Align the "T" nuts with the slot in the mating extrusion and place the panel on the corresponding extrusions. Tighten the screws in turn one panel at a time. Turn any one screw no more than 720 degrees before moving to the next screw. This insures the panel will be held in place without warping the frame. Use a builder's square to ensure the extrusion frame is square when all screws are completely tightened. Leave the top cover off until after the side Plexiglass panels are installed.
All three plywood panels can be cut from one 4'x4' sheet.
The nuts will initially turn 90 degrees and lock in place before the nuts begin to tighten.
Add Plexiglass Panels
Measure the distance from the bottom of each extrusion slot to the bottom of the opposing extrusion slot on each side panel. Cut the two 2 side sheets accordingly using a fine finish blade or router to the dimensions just measured.
Remove the top side extrusions and slide the panels down the slots on the vertical extrusion slots and into the slot on the bottom side extrusion. Replace the top extrusions and install the top cover temporarily.
Add Plexiglass Door
Cut a Plexiglass sheet to the dimensions of the front frame. Do not overlap unto the Plywood top and bottom covers.
Carefully cut the resultant sheet 20mm from the RH edge (Left if you want a LH hinge). The saw kerf will provide clearance between the panels to allow the door to swing freely.
Install three plastic hinges using Acrylic cement. Do not use excessive amount of cement! Hold each hinge in place using clamps until the cement sets. Average cure time is 3-5 minutes.
Drill 3 evenly spaced 5mm screw holes in the 20 mm stationary Plexiglas strip created above 10mm from either edge. Install door using 3 M5x8mm Button Head Hex Socket screws and 3 "T" nuts.
Install Door Handle using hardware supplied with the handle .
Install magnetic door catch using 2 M5x8mm Buttom Head Hex Socket screws and "T" Nuts. Cement the steel plate to the inside of the door opposite the frame mounted magnetic catch using the Acrylic cement listed in the BOM.
See door detail below.
Front Door Installation
Drill one and optionally a second 1.5" hole(s) for power and data cables. Install locally obtained furniture grommets with covers. The covers are necessary to restrict airflow through the openings during printer operation. See above right grommet with the i3 power cable and air scrubber cables installed. The left side grommet is obscured by the printer frame.
Temporarily place the printer in the enclosure and determine best location for the filament to feed through the top cover. Remove the printer and top cover. Using a router or Dremel rotary tool cut a 12x22mm hole at the location previously determined to be the best location for the Filament guide. Print and install the Filament Guide.
Install strip LEDs listed in the BOM on the top inside cover 20mm from the front and sides and 50 mm from the aft edge. Connect each strip together with 8mm "L" shaped connectors. Replace the top cover and connect a 12Vdc power source to the LED lead. In the case of the i3 I tapped 12Vdc off the i3's power supply. This should have no adverse affect on the power available to the printer since the LED drain is minimal.
Optional HEPA Filter
If a filter is desired (encouraged) drill a 36mm hole in the aft plywood cover at an appropriate location for your printer and install the Filter using the bracket supplied. The filter shown in the above photo is documented here:
Extrusion End Caps
Print and install 8 Extrusion End Caps. See below:
Extrusion End Cap Install
Thoroughly clean the enclosure, especially the interior. Install the 3D printer and connect power and data cables as required.
Be sure to follow printer manufacture's setup and calibration requirements whenever the printer is moved from one location to another.
Install the filament in an appropriate holder on the top cover and feed the filament through the guide and load into the printer.
Bill of Materials
- 2 ea 500x653mm 1/2" Plywood Panel (Top & Bottom)
- 1 ea 420x540mm 1/2" Plywood Panel (Back)
- 2 ea 1 1/2" Grommets (Aft Panel Wire Penetration)
- 1 ea Magnetic Door Catch