Lack Hack: Lulzbot Mini Enclosure

Want to print in ABS and print taller and larger objects? You’ll need to enclose your 3D printer. Drafts and fluctuations in temperature can lead to failed parts – poor layer adhesion, prints stuck on the hot-end and tearing away from the bed.

I’ve used a black garbage bag to help and I’ve got surprisingly good results – for a garbage bag, but it looks ugly and I’m sure isn’t the safest way to print.

I decided to use IKEA LACK tables as a basis for my enclosure. I want a larger enclosure that would allow a bigger printer or addition of other features in the future so I chose to go with a “3x” LACK design. My first step was going into TinkerCAD to work what I wanted the cabinet to look like.

Two LACK tables will be glued together, with their tops together. I changed the way I put the “middle” LACK together so that I could keep the finished side of the LACK showing. I also wanted an aesthetically pleasing design...which I think I ultimately achieved. I purchased Acrylic sheets, consumables, and hardware, but printed all the parts except the PVC pipe and caps. I also wanted the enclosure to match the coloration of my printer so I used the Lulzbot-branded-green colored ABS to print the parts.

The community has already produced some great parts so I repurposed readily available “things” from Thingiverse.com for this build.

Parts & Supplies:

3D Printed Parts

36x Brackets (http://www.thingiverse.com/thing:1802737)
3x Door hinges (http://www.thingiverse.com/thing:1831572)
1x Door handle (http://www.thingiverse.com/thing:1920010) - handle.stl only
2x Magnetic bracket (http://www.thingiverse.com/thing:2186895)
4x LACK stacking feet (http://www.thingiverse.com/thing:1418251) - LACK_Feet.stl only
1x Filament guide (http://www.thingiverse.com/thing:2114888)
2x Filament spool holder (http://www.thingiverse.com/thing:1424791) I “remixed” this part
2x Filament spool holder riser – another “remixed” part from the Spool Holder

Hardware:
120 6 x 5/8 sheet metal screws
8 M3 x 6 screws
4 #6 ¾” screws
4 10-24x machine screws
2 ¾” sheet metal screws
3 M4 machine screws
4 3/16” washers
2 ¾” washers (as ferrous as possible)
20 M4 washers
6 M3 washers
6 M3 lock washers
6 M3 hex nuts
3 M4 Nylon lock nuts
4 Acorn nuts (fit 10-24x machine screws)
3 Neodymium magnets 18mm x 3mm
4 48cm x 65cm sheets of Acrylic
24” section of ¾” PVC pipe
2 ¾” PVC pipe end caps
60” of ¼” fuel tube, black

Tools:
Lulzbot Mini
Screw drivers (Philips head)
Utility knife
Scissors
Metric measuring tape
Dremmel w/ cutting wheel
Power drill
Drill bits
Jigsaw
Hacksaw
Quick release clamps
Sawhorses
Miter box
Table
Extension cords
Straight edge
Scraps of wood

Consumables:
3 IKEA LACK tables, black
Paper towels
Liquid Nails
Gorilla Glue
Blue painters’ tape
Sandpaper, 320 grit
Sanding sponge
Pencil
Sharpie
Glue stick
Lulzbot Green ABS Filament by Village Plastics

Printing parts: Besides the curing process for the Liquid Nails, printing parts took the most time and the design process in TinkerCAD helped me make sure I could visualize the project in a way that a line drawing could not.

I printed my parts in multiples, if possible, and made sure I cleaned the PEI bed after each print – I also use PVA glue (purple Elmer’s Glue stick) – to make sure my print adheres. I have a tendency to watch the first layer like a hawk because I find a few things can happen:

· auto-level sometimes does not do its job. More than once I had the hot end traveling through the first layer, this can result in a print that sticks to the print-head and fails,

· Nozzle will not clean properly (and auto-level will fail). If you walk away, you have a potential of 30-60 minutes wasted.

· It is oddly hypnotizing.

During one print, I discovered a new way for a print to fail. With 12 brackets printing the print head stopped traveling freely. I had some serious macaroni salad on my print bed…and I was 2 ½ hours into the print. It seems that the filament was wound over itself on the spool and was so tight it would not allow the print head to move in the x-axis. I now check my spools of filament before each print.

a. Assemble “bottom” LACK per instructions from IKEA.

b. Using a sanding sponge, scuff the surface of table top. This will help with adhesion

c. Assemble “middle” LACK with the finished side facing down. This table will be secured to the top of the “bottom” LACK with Liquid Nails, finished side facing up, so that the “middle” LACK’s legs are pointing up.

d. Using a power drill and the 3/16” bit, drill through the unfinished side to the finished side using the existing hole. Use blue tape and drill slowly to prevent splintering of the finished side. Repeat for all four corners.

e. Apply Liquid Nails to the top, finished surface side of the “bottom” LACK. Place the “middle” LACK on top and secure with quick release clamps. Ensure sides are aligned. Allow for ample curing time (package recommends 24 hours).

During assembly I put Liquid Nails near the screws provided in the LACK kit to ensure a secure fit.

f. Install four legs using the included hardware.

a. Apply liquid nails to the face up legs.

b. Align the printed LACK stacking feet on the legs.

c. Secure each stacking foot to the leg with one #6 ¾” screw.

a. Tape around the midpoint of the legs with blue painters’ tape and measure the half-way point, 20cm from either end.

b. Place each leg in the miter box and slowly saw through the side of the leg with the hacksaw. Do not cut all the way through. Remove the saw and rotate the leg once the saw is through the side until the top of the blade is just below the surface. LACK table legs are hallow and you will get a more accurate cut if you rotate the leg to cut on each side.

c. (Optional Step) Fill the cut, hallow legs with 50% Gap filler. Do not overfill. The foam may not look like it will completely fill the leg, but it will expand and rise out the top, like a head of beer. If you overfill the leg, you run the risk of splitting it. To prevent splitting, if you do overfill, use cardboard scraps to slice the top off as it continues to rise out of the leg. Cure time is around 8 hours.

a. Trace the footprint of the Lulzbot Mini on the top of the third LACK table.

b. Find the mid point of the Mini’s footprint. Cover with blue tape to prevent damage to the LACK surface.

c. Measure 17cm from the back of the footprint towards the mid point. This is where the filament enters the print head on the mini.

d. Using the printed filament guide as a template, trace around the foot of the filament guide.

e. Drill pilot holes for the jigsaw using an appropriately sized drill bit. To protect the finish start with smaller drill bits and work up to a 3/16” bit. You may need to drill multiple holes close to one another to fit the jigsaw blade.

f. Cut out the hole for the filament guide using the jigsaw.

g. Turn the tabletop over and check the underside to see if the cut went all the way through. Trace the foot of the filament guide on the underside of the table to make sure the guide fits properly. Go slow and make additional cuts or pilot holes as needed.

h. Add Liquid Nails to the filament guide before inserting it into place.

a. Ensure the legs are level at the open end if using Gap Filler from Step 3c. Use a serrated saw blade to remove excess material.

b. Attach legs to the “top” LACK per IKEA provided instructions. Add liquid nails around the screw before fully installing the legs to the tabletop.

c. Test fit the “top” LACK table to the LACK stacking feet on the “middle” LACK. Remove the “top” LACK and add Liquid Nails to the LACK stacking feet.

d. Carefully fit the “top” LACK in place. Add weight to the top of the table to keep it from moving and to add some weight to the enclosure while working.

Optional: Add quick release clamps to keep the legs in place for the recommended period of time until the liquid nails cures.

a. The top portion of the enclosure is 55cm x 55cm x 70cm. The Acrylic sheet will fit between the two LACK stacking feet on either side of the enclosure. The Acrylic is 48cm x 65cm. The tall edge will be 3.5cm from the side of the enclosure and the short edge will be 2.75cm from the top and bottom edges of “top” and “middle” LACK tables respectively. Use a straight edge to connect the measurements.

b. Place a bracket along the bottom edge, aligning the inside of the bracket to the line drawn. The bottom of the Acrylic sheet will rest on the inside ledge of the bracket. Trace the bracket and mark, with a sharp pencil or score with a pointed object the three holes in the bracket. Repeat this step for two more brackets along the bottom of the “middle” LACK. Once installed these three brackets will hold the Acrylic in place while you measure and position the remaining nine brackets for this side of the enclosure. Secure the Acrylic sheet with blue painters’ tape if required.

c. Drill pilot holes for the screws using a 2mm drill bit.

d. Add liquid nails to the holes on the side of the bracket facing the enclosure.

e. Use 3 of the 6 x 5/8” sheet metal screws to attach each bracket to the enclosure.

f. Use the top of the “middle” LACK as a guide and place the bottom bracket vertically. Trace the bracket.

g. Drill pilot holes for the screws using a 2mm drill bit.

h. Add liquid nails to the holes on the side of the bracket facing the enclosure.

i. Use 3 of the 6 x 5/8” sheet metal screws to attach the bracket to the enclosure. Repeat for the top bracket on the left side, this time using the bottom of the “top” LACK as the guide.

j. Find the middle point between the installed brackets on the side of the enclosure -25.25cm from either of the vertically installed brackets – and install the middle bracket. Repeat steps f. through j. for the opposite side of the Acrylic sheet.

Because the tables are not designed to make an enclosure frame, there is some overhange between the bottom and/or top of the tabletop and legs. Do not completely tighten the screws for the side brackets until you have the Acrylic in place.

l. Using the brackets installed at the bottom of the enclosure as a guide, position three brackets in place along the top. Place the Acrylic in the already installed holders, and carefully align the inside of the three top brackets with the top of the Acrylic sheet.

m. Trace the brackets and mark the positions of the holes for the top- left, right, and middle positions.

n. Drill pilot holes using a 2mm drill bit.

o. Add liquid nails to the holes on the side of the bracket facing the enclosure.

p. Use 3 of the 6 x 5/8” sheet metal screws to attach each bracket to the enclosure. Tighten all screws on the side when finished.

It is highly recommended to use a screwdriver instead of a drill to install the brackets. Over-tightening the screws may crack the printed ABS parts or damage the LACK tables.

Use the template to make cuts in the Acrylic sheet for the Lulzbot Mini’s cooling fan and the power and USB cables.

a. Place the Lulzbot Mini inside the cabinet. Leave some filament inside the print head. Fit the Mini inside without a spool attached or spool arm up.

b. Position the Mini under the filament guide and adjust its position until the filament fits into the guide. The filament should not enter the guide at an angle. The cooling fan vents should be even with the left edge of the enclosure table.

c. Trace the footprint of the Mini inside the enclosure. This will help if the Mini is bumped or moves otherwise during creation of the template.

d. Using cardboard or paper, cute out a piece that fits over the Acrylic sheet Use the Acrylic as a guide or measure and cut to 48cm x 65cm.

e. Use blue painters’ tape to place the template over the enclosure where the Acrylic sheet will be installed.

f. Trace the profile of the Mini’s cooling fan enclosure and power and USB cables.

g. Remove the template. Use the power cable and USB cable to make sure the thickest part can fit through the opening and make adjustments as needed.

h. Attach the template, with the pattern facing the Acrylic sheet. Turn it over and view the pattern through the Acrylic. Trace the patterns on the protective film.

a. Clamp the Acrylic sheet to a work surface.

b. Drill pilot holes in the Acrylic sheet. Start with small drill bits and drill slowly. Work up to using bigger drill bits gradually. Drilling with a bit that is too big will catch the Acrylic and splinter, shatter, or break the piece. The power and USB cable cut-outs may require more pilot holes than jigsaw work.

c. Cut along the pattern traced onto the Acrylic sheet with the jigsaw. Be careful as the jigsaw may catch and move off of the cutting line.

Following the steps in Step 6 - Measure Location & Install Brackets for Rear Acrylic Sheet.

Sand the cut outs with 320 grit sand paper. Wrapping the sandpaper around a sharpie or pen is a good way to get corners or other areas unreachable by a full sheet.

a. Use the same measurements used in Step 6 for positioning the door on the front of the enclosure:

· 55cm x 55cm x 70cm for the front of the enclosure

· 48cm x 65cm for the Acrylic sheet

· 3.5cm from the top and bottom of the enclosure

· 2.75cm from the sides of the enclosure (should position between the LACK stacking feet

b. Hang the Acrylic sheet in position using blue painters’ tape. Check that the sheet is level so the door opens and closes correctly.

c. Use blue painters’ tape to attach the assembled hinges on the edge of the enclosure. Use the bottom of the “middle” LACK table as a guide for the bottom hinge, the bottom of the “top” LACK table as a guide for the top hinge, and the middle hinge should be 20cm down from the top hinge.

d. Fold the hinges over so that they are flat against the Acrylic sheet and mark the holes with a pointed object or pencil.

e. Drill pilot holes for the screws using the 2mm drill bit for each hinge – 2 per hinge, 6 total. Drill slowly to prevent breaking the Acrylic on the other side.

f. Find the mid point of the door handle bracket and mark with a pencil.

g. Find the mid point of the left side of the door (32.5cm from the top of the enclosure) and mark on the side of the door.

h. Align the door handle bracket with the mark on the side and position on the Acrylic sheet. Hold the door handle bracket in place with blue painters’ tape.

i. Mark the holes with a pointed object or pen.

j. Drill pilot holes for the door handle bracket and hinges.

k. Secure the hinges to the side of the enclosure with 2 6 x 5/8 sheet metal screws per hinge.

l. Install the hinges to the door using the M3 x 6 screw, M4 washer, M3 washer, M3 lock washer, M3 hex nut.

m. The inside M3 screws need to be cut in order to fit under the handle. 3 of the M3 screws were held in place with painters’ tape and a clamp and cut with a dremmel rotary tool and a cutting wheel on a work surface.

n. Install the door handle and door handle bracket using the 2 ¾” sheet metal screws. Use a bigger drill bit to increase the size of the pilot hole – work from 1/8” bit to 5/32” bit. Drill slowly to not break the opposite side of the Acrylic. The bracket goes on the inside and screws into the handle.

a. Carefully place the 18mm x 3mm neodymium magnet inside the magnetic bracket and place the bracket cover over the magnet.

b. Use the M3 x 6 screws to secure the cover. The magnet is strong and will pull towards the screws. Repeat for the second magnetic bracket.

c. Place one of the magnetic brackets along the left leg of the “middle” LACK tabletop with the back facing towards the door. Trace the bracket foot.

d. Apply liquid nails to the bottom of the bracket foot and install using two 6 x 5/8 sheet metal screws.

e. Place the second magnetic bracket along the top, inside, left leg of the “Top” LACK with the back facing towards the door. Trace the bracket foot.

f. Apply liquid nails to the bottom of the bracket and install it to the bottom of the “Top” LACK tabletop using two 6 x 5/8 sheet metal screws.

a. Place the washer on the magnetic bracket. Shut the door and trace the washer on the outside of the Acrylic sheet.

b. Open the door and use Gorilla Glue to secure the washer to the Acrylic door. Ensure you peel the protective film away before affixing the glue or washer to the inside of the door.

c. Repeat the process for the bottom washer and magnetic bracket.

The door will hold but is not as strong of a seal as I’d like. I placed another Neodymium magnet on the outside of the door over the washer to create a stronger bond.

a. Cut the tubing into one 26cm and two 22cm lengths.

b. Straighten and secure the tubing to a piece of wood or table using blue painters’ tape.

c. Cut about a 2cm starter cut on one side of the tubing using a pair of scissors. Do not cut all the way through the tubing. Continue the cut all the way up the tubing with a utility knife. Cut slowly to make as straight a line as possible. Insert the back end of a sharpie in to loosen up the split tubing and allow for an easier installation onto the Acrylic sheet.

d. Repeat the process for the remaining 26cm and 22cm pieces.

e. In order for the two 22cm pieces of fuel tube to sit against the top tubing, cut a slot out of the tubing so that it fits the 26cm tubing. Hold the 22cm piece up against the tube and trace with a pencil. Return to the same work surface and use the scissors and utility knife to cut away the piece of tubing.

a. Draw a straight line through the center of the filament guide on the top of the enclosure.

b. Use a filament spool holder as a guide and find the center point (6.5cm from either edge of the spool holder). Align the center of the spool holder with the line drawn through the center of the filament guide.

c. Using a long 5/32” drill bit, drill through the holes of the filament spool holder through the top of the enclosure.

d. Thread a 10-24x machine screw with a 3/16” washer on the screw through the hole made on the inside of the enclosure. Move slowly to not miss the hole on the top of the enclosure. The LACK is hallow and if it is threaded in quickly, the machine screw could puncture the top side of the LACK.

e. When the screw is flush with the top of the enclosure, apply liquid nails to the holes of the filament spool holder riser. Finish threading the machine screw from the inside of the enclosure until flush with the top of the riser.

f. Apply liquid nails to the hole and underside of the filament spool holder and attach to the top of the riser. Complete threading the machine screw from underneath until it is all the way through the top of the spool holder.

g. Attach the acorn nuts over the exposed machine screw and finger tighten.

h. Repeat for the opposite side spool holder and riser.

i. Slide the ¾” PVC pipe through the top of the filament spool holders and cap each end.

To attach spools of filament, remove a cap, slide the PVC pipe all the way through one end, and place your filament on the PVC pipe. Slide the pipe back out of and recap the spool holder.

Place the enclosure in its designated spot, remove dust, debris, liquid nail remnants, protective film from Acrylic sheets, and install the Lulzbot Mini. Plug in, print on!

#Rocktopus