Introduction: 3D Printer Enclosure

About: I am a large mammal. http://www.thingiverse.com/schlem/designs http://www.youtube.com/user/Schlemmerwood

Not long after assembling my 3D Printer (the Schlabricator ), my wife, Beehive, AKA She-Who-Must-Be-Obeyed, banished my beloved, but slightly odorous machine to the garage. The structure, originally built for Model-T era vehicles, is behind the house and unusable as a garage, owing to a gnarled Russian Olive that obstructs the driveway.  There is power to the building, but no heat, and therein lies the motivation for building an enclosure for my Printrbot.  When the weather is coolish - in the 40's - it takes an inordinate amount of time for the heated bed to actually heat up. I have experimented with insulating the glass with a blanket of paper sheets, but it still takes far too long, and the temperature plummets when the "blanket" is removed. 

UPDATE: I've been using this enclosure almost daily since I built it and I can tell you two things: it works great at trapping heat and controlling the thermal environment around your printer, and that the vent is a useless vanity. Sure, it looks cool, but if it is warm enough to warrant venting the enclosure (as it was occasionally during the summer), I just pull the hinge pins and remove the door. DON'T drop the door! Just sayin'   I am building a smaller enclosure for another home-built 3D printer that I am dedicating to ABS after frustrating experiments with PLA. 

Other uses for a 3D printer enclosure might include mitigating fumes, noise abatement, or protection from dust or inquisitive felines.  Regardless, join me on my 3D Plexiglass adventure...

Step 1: Methodology (or "Let's Go to Home Depot!")

My first vision for this project was an off-the-shelf metal hardware solution for building sheets of plexiglass into a box to contain my Printrbot.  As I wandered the aisles of Home Depot, a quiet Voice in my head reminded me that I could print the brackets that would join the plastic together. I dismissed the voice as I weighed the merits of various shiny galvanized doo-dads hanging in neat rows on the perfboard display.  With a tentative mental blueprint in mind, I collected what I thought I needed: the 1/8th inch-thick plexi, assorted corner braces, nuts, bolts, hinges, and headed back to the ranch.  

I worked with acrylic in high school shop, and we glued and drilled and sanded our key fobs and pen holders with abandon.  However, when I put my drill bit to the plastic, regardless of altering variables like pressure, RPM, or bit size, the plexiglass would typically (and violently) crack. 

I'm sure most of you are way ahead of me at this point, but after a dozen such fabrication failures, the Voice in my head became impossible to ignore: "Print the hardware and glue the box together"

Me: "Maybe I should just print the hardware..."

Inner Voice: "Geesh"

My mental blueprint just got Etch-a-Sketched, but the vision was clearer now.  Little ABS blocks would hold the plexiglass square, glued into the corners and along the edges.  I would still need to run wires into, and potentially vent excess heat out of the enclosure, so I hoped that hole saws would work better than the drill bits.

As luck would have it, I now possessed an extra, albeit cracked, piece of plexi to experiment on.  Even though, at the heart of every hole saw is a drill bit, the test holes that I produced involved no catastrophic cracking.  

This just might work.

Step 2: Materials and Tools

After an undisclosed number of trips to various hardware stores, this is what I collected to build my 3D printer enclosure:
5 sheets of "Optix" acrylic sheet, 1/8" thick, 18 X 24  inches  - $10 at Home Depot- consider an extra sheet to practice cutting and drilling.  You could buy thicker (1/4") sheet, but it's more expensive, and probably vastly more difficult to cut accurately. 
Devcon Home Plastic Welder  (This is an epoxy with solvents in it that will bond ABS to Acrylic - very nasty stuff.  I also used Duco Cement to glue ABS to ABS.  More on glues later)
1 inch hole saw
2 inch hole saw
(I just bought the cheapest ones available, about $5 ea at Home Depot)
Rare Earth magnets for closing door (about $4 at Home Depot)
Masking Tape
#6 wood screws (to hold everything down on your workbench)

These are the tools I found useful:
Straight edge or Framing square - good for cutting plexi and checking your angles
Cordless drill  and assorted drill bits
Tape measure
Pocket knife for scribing plexiglass and various trimming duties
Sand Paper for smoothing acrylic edges and ABS surfaces 200 - 400 grit
3D printer to create the gizmacci used to join the acrylic sheets
Flat work surface, large enough to allow you access to all sides of your enclosure-in-progress. (I used the kitchen floor)


Step 3: Cutting Plexiglass

The dimensions of the acrylic sheets lend themselves handily to a box large enough to contain my Printrbot Plus.  I decided to make the enclosure 24 inches deep, which meant that I wouldn't have to cut three of the sheets.  From the other two sheets, I would cut out the back, the door, and two smaller strips to brace the enclosure at the top and bottom of the door.

Nominal dimensions
TOP, LEFT and RIGHT sides: each 18 x 24 inch, whole sheet of acrylic
BACK: 18 X 17 3/4 inches  (must fit between the sides)
DOOR: 17 X 17 3/4 inches  (must fit between the sides and not bind at the top and bottom of the enclosure)
BRACES: 2 X 17 3/4 inches (inserted at the top and bottom of the door, positioned behind and inside the door.)
Finished enclosure will measure 18 1/8 inches high, 24 inches deep, 18 inches wide.

The top sits upon the sides and back, such that the width of the top sheet dictates the width of the back (or door) less the thickness of the sides.  If the top is precisely 18 inches wide, the back will be 17 3/4 inches wide (each side is 1/8 inch, remember?) 

Please, actually take a moment and measure the width of your acrylic.  Mine were a just a bit wider than the advertised 18 inches, and when I cut the back and door, I found them slightly narrower than they could have been. While we're at it, I found a couple of sheets at Home Depot that weren't square either.  With the goals of minimizing errors and efficient cuts, checking your stock with a tape measure and a square at the big box store can save you some grief.

The best method I found to cut acrylic sheet involves almost no cutting.  The acrylic is covered on both sides with a protective film - handy for marking measurements and keeping the plastic unscathed.  
1. Carefully measure and mark the cut you wish to make on the film.
2. Align a straight edge along the line.
3. Carefully cut the protective plastic film along the intended cut with the pocket knife.
4. Keeping the straight edge on the line, turn the knife over, and using the point, BUT NOT THE EDGE, scribe the line several times.  Repeatedly make deep scratches along the straight edge; done correctly, delicate shavings will peel from the acrylic.  
5. Repeat scoring on other side of acrylic sheet.  Take time to measure accurately - the scorings must be parallel. 
6. Clamp the sheet or hold it firmly under a straight edge with the scribe mark along the sharp edge of a counter or table. Apply a sharp downward pressure to break the sheet along the scribed line. 
7. The new edge can be lightly sanded or scraped with a knife blade to smooth.  A slight bevel will actually make the acrylic less prone to chipping and thus cracking. 

Step 4: The Gizmacci

Gizmacci  / 'giz ma chee' /
n. pl. gizmacci
A thing, device or part whose name is unimportant or unknown; a gadget, doohickey, thingamajig, thingamabob, doo-dad, or whatchamacallit.  Likely a portmanteau of gizmo and machine.

The following printable items are used in the construction of the 3D Printer Enclosure (click on links to download  from Thingiverse.com in STL format):

Gizmacci One
These are brackets for gluing up a right proper and square box from acrylic sheets (AKA plexiglass).

Gizmacci Two
These are extra brackets (should you need/want them) for gluing up a right proper and square box from acrylic sheets .

Gizmacci Three
This is an adjustable vent that sit atop the plexiglass enclosure to passively vent hot air and fumes through convection. This is designed to fit in 2 inch hole. I had very good success with a new hole saw at slow speed.

The pin the vent spins around is a section of 3.0 mm ABS filament that has the ends "peened" with a hot element, like a soldering iron. You can clean out the small hole with a 1/8" drill bit which is just a tiny bit bigger than 3.0mm.

Gizmacci Four
These are hinges for the door to the enclosure. The pin the hinge hangs from is a section of 3.0 mm ABS filament that has the end "peened" with a hot element, like a soldering iron. You can clean out the hinge holes with a 1/8" drill bit which is just a tiny bit bigger than 3.0mm.

These are designed for 1/8 inch-thick plexi sheets. There are two outside hinge elements that sandwich the middle hinge on the door. Mate the bottom element and the middle element such that their smooth (bottom) sides kiss. Your hinginess will be much smoother. The design of the faces that engage the plexi should suggest the area of glue application.

Gizmacci Five
This "tray" contains a swiveling pass-through and reinforcing rings for wiring/vent holes. All these parts are designed for a 1 inch hole. I had very good results with a new 1" hole saw at slow speed.

An annoying property of acrylic sheet is how edge defects from cutting or drilling can spawn heart-breaking cracks (ask me how I know this) I think reinforcing any hole through plexi is cheap insurance. The Pass-through will fit 1/4 inch sheet or 1/8 inch sheet (like I used) with a ring as a shim. The images should demonstrate how the Swivel Pass-through works. Be careful not to accidentally glue your swivel ball in the rings - it should move freely and be loose.

Skull Knob
Since the two pieces are the same material, bonding them is easy, Use your favorite ABS glue or plain ol' acetone should work. This shrunken head was derived from "Cleaned Skull" by ssd. I added little round eyeballs in the orbits. Zoinks!

Additionally, you will want some way to keep your 3D printer from banging off the walls of the box - I recommend the Vertical Board Anchor by CodeCreations   The are countersunk to take #6 wood screws and they perfectly fit the 6mm ply from which my Printrbot is made. 

Step 5: Holes

Before you begin to fit the pieces of Acrylic together, the holes for ventilation and wiring should be cut.  I can say with some authority that cutting holes after the box is assembled is a PITA.

Use a gentle pressure and a slow speed.  Ensure that the hole saw engages the plastic uniformly around the perimeter when the teeth make contact with the acrylic.  Remember that extra sheet I suggested?  Practice will pay dividends.  

TOP: 2 inch hole for the adjustable vent (Gizmacci three).  I cut this hole in the center of the sheet, 16 inches from the front edge, but it could go anywhere.

LEFT side: 1 inch hole for swiveling pass-through and power cable hole (see Gizmacci five).  The swiveling pass-through I positioned 16 inches from the bottom, 16 inches from the front.  In this location, the filament assumes a gentle arc from the spool to the extruder, and the pass-through easily accommodates slight changes in direction as the extruder moves.  I also positioned the power cable hole 16 inches from the front, centered 3 inches above the bottom edge.  

RIGHT: The data cable to my laptop passes through a hole situated 16 inches back and centered 3 inches up, like on the the LEFT side. 

Step 6: Initial Fitting

Having cut the acrylic sheets to size, the basic box takes shape rapidly.  Carefully determine which sides will be on the inside; remove the protective film from these inside surfaces (Don't take the film off the door yet).  Position the sheet that will be the top of the enclosure, upside-down on the floor, with the unprotected side up.  The sides, back and door will be erected on the inverted top of the box, flush with the top's edges.  

I used blue masking tape to hold the sheets together, using another piece of acrylic as a square to make a tight and flush joint at the edges.  Taking your time at this stage will allow you to fine-tune the fit of the pieces.  Check and double-check the joints in the corners and along the edges.  Once you are satisfied with the fit, use copious tape to hold everything tight and square.  

You'll notice in one of the photos that I cut the back and front doors short under the assumption that the top was precisely 18 inches wide (it was wider).  I should have cut them the width of the top minus 1/4 inch.  

If you cut the door less than the 18 inch height, as I suggest to minimize binding at the top and bottom, for initial fitting, position the door flush with the top of the box.  The braces go inside the door.  Tape the braces into place inside the door, leaving the ends free from tape so that a bracket can be glued into each corner.  Leaving the film on the door will prevent any glue from sticking if it should contact the door.  The door is only helping to define the shape of the box at this point.  

Step 7: Gluing the Box

A few words about glue: To glue ABS and Acrylic takes some specialized chemistry.  Or not.  This was the most frustrating aspect of this project.  I only know what I have read, and I read that there are glues especially formulated for just this union.  The Interwebs are abundant in information about glues, but the dozens of consumer products on display use vague labeling and lack definitive product numbers that would identify the right formulation. There are plumbing glues, notably Weld-On 1802, but in all of my many trips to hardware and plumbing supply places, I could not find it.  Also suggested were various cyanoacrylates or Super Glues.  You might find something comparable but I finally found an epoxy-based product called Devcon Home Plastic Welder.  If you know of a suitable product or try a different methodology (simple acetone was suggested), please leave a comment. 

One more word about glue: VENTILATE.  You only get one brain, and the methyl ethyl mess you up in most "plastic glues" is particularly toxic. 

After your holes are cut, your box is fitted together and square, and you have printed out the gizmacci to join the acrylic sheets, you are ready to glue it together.

Double-check that the protective film is removed from the inside surfaces and from the inside surfaces of the braces.  The braces should be taped in position at the top and bottom of the front of the box, behind, inside the door.  You can get an idea about the braces positioning from the picture of the completed enclosure.  

Using sand paper on a flat surface, prepare the areas of the gizmacci that will receive the glue - sand down any irregularities and roughen the surface.  In many cases, the "down" side of the printed part is NOT the side that is being glued.

Work in small batches, mixing small amounts of glue (the working life of the Devcon glue is only a few minutes).  The larger the volume of epoxy, the faster it sets.  I found that by the time I had buttered and positioned 4 printed gizmacci, the glue was beginning to become too stiff to spread evenly.  Gizmacci one and two should provide ample brackets to join your sheets together.  Careful planning and fitting of the brackets will result in a neater job.   

To begin, you should glue in the 3-sided pyramids in the top corners, and the "feet" with the holes in the bottom corners.  Keep in mind, at this point in the assembly of your inverted box, the top corners are down and the bottom corners are up. On one end of the box, brackets are glued to the 2 inch-wide braces that are positioned inside the door.  Other brackets can be used to join the sheets along the edges.  I only used one extra bracket on each edge, but 2 brackets will hold the braces securely at each end. 

Step 8: More Gluing

Your box should now be held together by some combination of Gizmacci one and two.  A little poem: It will be noticeably flexy, when made from 1/8 inch plexi. 

If you haven't already, use sand paper on a flat surface to prepare the areas of the gizmacci that will receive the glue - sand down any irregularities and roughen the surface.  In many cases, the "down" side of the printed part is NOT the side that is being glued.

Gizmacci three is an adjustable vent that fits in the 2 inch hole in the top sheet of you box.  The center pin is a section of 3.0 mm filament that has the ends "peened" with a hot implement like a a soldering iron. You can clean out the center holes with a 1/8" drill bit which is just a tiny bit bigger than 3.0mm.  Before you glue Gizmacci three in place, turn the box over, ensure that the protective film is pulled back from around the hole on top of the enclosure.  I think you get a better result if you spread the glue on the perimeter of the hole and then position the vent.  

Gizmacci four are the hinges upon which the door will open.  The pin the hinge hangs from is a section of 3.0 mm ABS filament that has the end "peened" with a hot element, like a soldering iron. You can clean out the hinge holes with a 1/8" drill bit which is just a tiny bit bigger than 3.0mm.

These are designed for 1/8 inch-thick plexi sheets. There are two outside hinge elements that sandwich the middle hinge on the door. Mate the bottom element and the middle element such that their smooth (bottom) sides kiss. Your hinginess will be much smoother.  These instructions assume a left side installation.  The design of the faces that engage the plexi should suggest the area of glue application.

The vertical positioning of the hinges is not critical.  Before gluing the hinges, remove all masking tape and protective film from the areas to receive the hinges.For best results, predetermine the order in which you will glue the pieces of the hinge assembly, laying them out logically before beginning.  Starting with the bottom elements, mix a small amount of glue and carefully apply to the surfaces that will contact the side of the enclosure, with caution to avoid getting glue on the door.  Allow these two pieces to set before gluing the middle element of the hinge assembly to the door.  Again, take care not to get glue on the other sheet of acrylic when gluing this part, and to snug it up against the bottom element, flat side to flat side, for maximum hinge happiness.  Let the middle portions of the hinge set also, then glue the final, top elements, like before.  

Gizmacci five consist of the swiveling pass-through and 5 - 1 inch rings.  An annoying property of acrylic sheet is that edge defects from cutting or drilling can spawn heart-breaking cracks (ask me how I know this),  I think reinforcing any hole in plexiglass is cheap insurance. Glue the rings to each side of the wiring access holes, and trim any excess glue from the inside of the hole. 

The sphere of the pass-through should be glued together and smoothed before assembly. I used Duco cement to bond these part together, but you could probably use acetone or other "model glue".  After gluing the spherical hub, I trimmed off the ridge from the joint and lightly sanded the ball.  The captive portion is slightly smaller than the inside dimensions of the contoured rings and when glued together, it should be loosely held.  The Pass-through will fit 1/4 inch sheet or 1/8 inch sheet (like I used) with an extra ring as a shim. The images and photos should demonstrate how the Swivel Pass-through works. Be careful not to accidentally glue your swivel ball in the contoured rings - it should move freely and be loose.

Skull Knob The door on the enclosure needed a knob, and, because organic forms like skulls look awesome when 3D printed, I took a 3D model of a skull, chopped and squashed it, and stuck it on a knob.  There is a hole in the bottom for a screw, but a small blob of Devcon Home Plastic Welder is up to the task of sticking it firmly to the front, so no holes need be drilled; no cracks need occur. 

Magnetic Latch Lastly, I used tiny blobs of the Plastic Welder (it's epoxy at heart) to glue super-strong rare earth magnets at several points on the face of the door.  The beautiful thing about this is that the magnets are self-clamping. I put them in place, sticking to each other through two layers of plexiglass, on the inside, on the brace, and on the outside of the door.  After applying some glue adjacent to  the magnets, I slid and spun the magnets into position so that the glue uniformly coated the inside surface of the magnets.  Boom!  

Step 9: Fasten It Down

Gizmacci one has four elements designed to go in the four bottom corners of the enclosure.  There is a hole in the bottom surface of this thing, intended to take a screw to hold the whole she-bang tight to your work surface.  I used #6 wood screws because I bought a box of them, but drywall screws would work just fine. Once you screw it down, you will be amazed at how stable the whole construction turns out.  

If you were so inspired, some kind of quick-release arrangement of pins and cotters to allow quick release and removal would be awesome. 

After all the trouble you have gone to make an enclosure for your 3D Printer, keeping your printer in place should be a priority.   I recommend the Vertical Board Anchor by CodeCreations   They are countersunk to take #6 wood screws and they perfectly fit the 6mm ply from which my Printrbot is made.  If you have another 3D printer, I got nothing; but find something - you'll be happier.

Wooo! Good Work!  Your 3D Printer is safely encapsulated in an insulating and protective enclosure.  You are in command, you are the master of the environment, you are the maker.

Enjoy.

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