Mini-Minion - the 3D printer for easy classroom production.
by CaptnBlynd, published
This is a Wallace/PrintRbot style 3D printer I designed for quick, multiple builds for a classroom type setting. I have named it the â€œmini-minionâ€ because every mad scientist needs a minion. I asked my local community education center if they would consider teaching 3D printing and associated technologies because I wanted to learn more. Somehow, now I'm teaching 3D printing and associated technologies at my local community education center. I have constructed 3 of these frames and completed 1 of these printers already so the files should be solid.
This Thing requires a drill press, a 3D printer and a saw able to make precise cuts. I use a radial arm saw. Most lumber sellers have a saw which they will do a couple cuts for you. The length is not critical on either set of cut parts but they must be EXACTLY the same. The sides are 1 x 4 x 18â€ which means actual dimensions of 3/4â€ x 3 1/2â€ x 18â€ to those of you who don't know lumber standards. 17 3/4â€ is fine. 18 1/4â€ is fine. AS LONG AS BOTH ARE THE SAME. The bottom spreaders are 1 x 4 x 12â€. Same applies but there are no holes to drill. I am using a product called AZEK. An extruded plastic meant for house trim. I find it very easy to use and nice looking. Use the bottom spreaders as your guides for setting the threaded rod before attaching it at the bottom. This give you verticle alignment. The drilling pattern is built in to the z axis motor brackets. Simply line the top edge of the bracket with the side board. Drill you boards together. I start by drilling a hole thru both side boards 1/2â€ from the top and Â½ â€œ from the side that is the diameter of the threaded rods. I use 5/16â€ you may use 8mm. I then put a 5/16 bolt in the hole to keep them perfectly aligned and do the same on the other end. Put a bolt in it. Position your bracket close to center and drill your holes. As long as you keep the same faces together the alignment will be perfect. I draw a circle on the end of the boards while they are still together to give me a reference in case the faces get confused. Line up the circle, you're in alignment.
The end rods are exactly the same as on a Prusa. The same nut bolt pattern and bearings. In fact, all of the rail system printed parts are from the Prusa depository on Github. I am using standard split cable cover from the hardware store. That is what the â€œslinky holdersâ€ are for. This is optional and frankly not entirely satisfactory.. The file labeled â€œmini-minion.stlâ€ is a label for the printer. Also optional. The â€œsupport-extruderâ€ is optional but it is likely you will need it with any j type hot end.
The reason this is a work in progress is because I need to give more complete assembly instructions BUT if you read the Wallace assembly I have credited as derived from and the Prusa instructions at the RepRap wikipedia site then you should have no real issues assembling this printer just from these notes. More detailed instructions and pictures to follow. The download includes all files and some helpful things like a bed drilling guide.
Guidler is the extruder 1 set for the size of your filiment
608adaptors (optional) 1
bushing-linear (optional) 11
x-end left 1
x-end right 1
Xlpulley (optional) 2
Threaded rod, 5/16" or 8mm x 14 1/2" 4 (2 z axis, 2 cross bars)
Threaded rod, 5/16 or 8mm x 16 " 1 (Top bar)
Smooth rod, 5/16" or 8mm x 18" 4 (2 z axis, 2 Y axis table rails)
Smooth rod, 5/16" or 8mm x 16 3/4" 2 (x carriage)
// by making the table wider than a standard heat plate we are able to place the leveling screws for easy access. I do not use the included bed drilling guide. I will provide one as I complete this.
Lower print table 10 1/2" x 6" 1
Upper print table 10 1/2" x 9" 1
* nuts and bolts a lot
608 bearings 6 (5 if you use an option on the x carriage)
lmu88 linear bearings 11 ( or print bushings)
NEMA17 stepper motors 5
Control board- printRboard-Gen6(or 7)- RAMPS 1 ( I own all 3. I prefer Ramps. Just me.)
end stops 3 ( I like the simple mechanical ones to start)
thermistor, 100k 2
hot end - j type designed 1 (other hot ends may mount. A standard j type WILL)
Heat plate 1
wires and connectors* I'll start counting
12v 30 amp power supply 1
Hobbed bolt 1
springs 6 (4 for table, 2 for extruder)
T2 pulleys 2 (if you use T2 belt, or print XL pulleys for XL belt)
Sheet glass, 8 1/2" x 8 1/2" with corners cut off 1 or more (people say to use tempered)
Binding clips for glass 4 (see photos)
Sheet cork gasket 8 1/2" x 8 1/2" 1 ( I use 2 layers. For under hotbed.)
If you don't get filiment then you won't be able to print!