Prusa i3: Graber edition: Mounting the Axes

Once the frame is complete, it's time to mount the axes - X, Y and Z.  To do this I printed various bits to make life easier, or to make the printer more robust.

Z Motor Install
First install the two Z motors - one on each side.  I twisted the cables first, to cut down on stray noise, then sheathed them so they'd look nicer.  There are slots in the base to run the motor wires, too.

For this step, you need:

• 2 Nema 17 motors
• 8 8-10mm M3 socket cap screws
• 8 M3 washers.

 
The next step is the X Idler, which will also construct the Z axis.

 You need:

• Wood: P, R, Q, Q, V, F, U, U.
• 4 1.5" 6-32 screws
• 4 6-32 nuts
• 1 M5 nut
• 2 LM8UU
• 2 3/4" 6-32 screws
• 6-32 washers
• 2 more 6-32 nuts
• 1 30mm M8 bolt (note: the one I used was too long)
• 1 608ZZ bearing
• 1 M8 nut (2 if your bolt is too long)
• 8mm Z Smooth Rod
• M5 Threaded Rod

The assembly is a bit confusing.  You have three horizontal plates, with three end caps and two internal spacers - best to check out the video.  Luckily, there's really only one way it'll work, and the X Motor mount uses the same configuration.

The long screws hold the assembly together; the short screws are used to clamp the M5 nut in between the two top plates.  That nut is your Z motion.  The M8 bolt holds the idler in place, making for a nice compact assembly.

 Here the M8 bolt I'm using is too long - if you use a 30mm bolt, you can go straight in - keeping the nut in between the first two plates, and then the idler resting on the end of the bolt.  I replaced this later.

The next step is the X Motor Mount.  The assembly is configured almost identically to the idler, except that there's a motor slapped onto the end.

Parts Needed:

• Wood: Y, X, Q, Q, W, AA, Z, Z.
• 4 1.5" 6-32 screws
• 4 6-32 nuts
• 1 M5 nut
• 2 LM8UU
• 2 3/4" 6-32 screws
• 6-32 washers
• 2 more 6-32 nuts
• 4 8-10mm M3 screws
• 4 M3 washers
• 8mm Z Smooth Rod
• M5 Threaded Rod
• 2 * 8mm X Smooth Rod
• 3 more LM8UUs - put 'em on the X rods before mounting them :-)  I forgot this step, had to dismantle a bit to get 'em in afterwards.

Y Assembly
Next up is the Y assembly.  For this, I printed two parts - an LM8UU holder, and a double nut trap - to make my life easier, and make the machine more reliable.

Parts Needed:

• Wood: O, O, O, O
• 6 10mm M3 screws
• 6 M3 nuts
• 3 LM8UU bearings
• 3 nut traps (http://www.thingiverse.com/thing:325681)
• 3 LM8UU clamps (http://www.thingiverse.com/thing:325681)
• 8mm Y Smooth Rod
• 4 1/2" 6-32 screws
• 4 6-32 washers
• 4 6-32 nuts
• 4 zip ties

Prusa i3: Graber edition: frame assembly

Once all the parts are lasercut it's time to assemble.  First, lay out all the parts.  I'm using a non-stick mat (slightly stained...) to keep screws/nuts from bouncing all over.  Small tupperware bins help keep the itty bits organized.


I took videos most of the time.  These are real-time; later I'll go back and make a condensed version, keeping only the essential steps.

Layout all of the parts

Assemble the Z Motor mounts & the frame

Assemble the base of the machine

Coffee is essential to any build process.  I'm doing this at 7 in the morning on a Saturday - while baby Scarlet sleeps in.

I didn't do much prepwork on this... some foibles included.  Assembling the front and the rear, including the Y axis motor and idler mounts.

 

 

 

 

 

 

 

Final frame pieces - the upper Z rod mount!

 Frame Complete!  If you have any questions, or want photos of  particular assembly let me know.

Prusa i3: Graber edition: lasercutting

Once the plywood was stained, I waited three days to make sure it was well and truly dry.  Then, LASER.

I'm using the laser cutter at nova-labs.org.  It's a 100 watt Hurricane Laser.

First Plate - this is the frame, X and Y axes, bed, motor mounts...

Second plate - this is two bases, and two LCD mounts.

The files are color-coded for cut order and intensity.  If you cut a part out completely, you can no longer cut inside of it - so you need to cut out the insides first, then the next border, then the next... etc.

If you look closely, the green hexagons are nut traps - meant to be cut halfway through the material.

The Raw lasercut files are in my Google Drive folder.  The dxf's are the parts, the rest are probably only applicable to Nova-Labs' laser.

You'll want to test the cut speed and power of your laser - I made a test set for cutting all the way through, cutting halfway through for the nut traps, and labeling. 

MY CUT ORDER

1. Red - speed 100, power 10 - these are the labels, just etching
2. Green - speed 30, power 50 - nut traps - cut halfway for nut traps
3. Black - speed 9, power 100 - all the screw holes/tiny stuff
4. Blue - The rest are all the nested parts.
5. Magenta
6. Teal
7. Yellow

You can use the cut order on any laser, but should adjust the speed and power settings.

Prusa i3: Graber edition: staining

Once the plywood arrived, I started to stain it.  This isn't purely cosmetic - I think it's an important step when building anything out of wood.

Untreated wood will swell and warp over time - especially plywood.  Because I had so many small pieces to be lasercut, I decided to stain first.

Underneath the panels is a non-skid pad for carpet.

Staining:

• Get everything ready.
• Gloves!
• stain
• stirrer
• opener
• trim tray
• brush - I like the foam ones
• paper towels
• wood!
• Put on your gloves, open the stain
• Spread stain on thin and quick - you want full coverage.
• Wait 5 mins - or just do three panels in sequence
• You'll need one and a half panels per printer.
• Wipe off excess stain with the paper towels - you want the wood grain to show through.
• Move panels off to the side, let dry 3 hours.
• When dry, rub with fine steel wool
• Apply a second coat.
• Now do the other side.

When you're done with a side, you can grab the foam part of the brush with your glove, and then take the glove off over the brush - sealing the wet paint inside and saving it for the next coat.

The red is called gunstock - I really love this color.  The black shows the panels after one coat, and then standing up to finish drying before lasercutting.

Prusa i3: Graber edition: sourcing

The first step to building a reprap is sourcing the parts.  It is by far the hardest step, aside from perhaps choosing which printer you want to build!  I chose the Prusa i3, or rather the Graber i3 - Shane Graber's lasercut rendition.  I picked it for the rigid frame and ease of assembly, but also because I could easily replace lasercut parts with printed ones - the machine can still upgrade itself, even if the upgrades aren't laser cut.

Some Notes on Acquisition

Where to buy from?  If this is your first rodeo, and you're only building one machine, I highly recommend a kit.  Buying oodles of parts from different suppliers can be a hassle, and often will only save money if you're buying more than one machine, or spending a lot of time scavenging deals.

I am sourcing four machines, and building two myself.  Right now I have less time than money - so my sourcing decisions may not match your own.

Last note: this is a video build.  I am filming myself with Google Glass, and I don't edit much.

I hope that was exciting.

Materials - initial run, anyways

• woodworkerssource.com
• $10.25 per printer - $41 for 6 sheets of 1/4" Baltic Birch plywood, 20"x30" 
• You need 1.5 sheets per printer, so six sheets = 4 printers
• McMaster-Carr
• $70.68 for 6 Smooth Rods - 8mm by 400mm precision steel shaft
• $10.72 for stainless steel threaded rod, 5mm by 1000mm long
• $24.62 for 3/16" Borosilicate glass, 8"x8"
• $23.73/4 for 25' of 3/8" heatshrink tubing (way more than you'll need for one printer... I'm stocking up).  Get the red heatshrink.
• $17.79/4 for polyester cable sleeving - if you don't make the printer nice, it's way harder to fix it later.
• $7.51/4 for 1/16" diameter high-temp sleeving - I'm going to try putting this on the thermistor.
• AliExpress
• $12.42 for 20LM8UU bearings (you need 10... order extra.  I ordered 60 for four printers)
• $3.40 for 6mm wide tensioning springs
• $14.00/4 for 50 625RS bearings - I think you only need 3 or 4.
• reprapdiscount
• $209 for Rumba Big Box with Smart LCD controller, endstops, Mk2B heatbed, 3 gt2 belts and pulleys, hall endstops, 2 thermistors, 1 40mm fan and a ceramic screwdriver
• Even I get the kit.  Makes sourcing much easier.
• E3d hotend
• $81.09 per hotend.  It's steep, but the hotends are very nice.
• Also kickstarted the Pico hotend.
• Fastenal.com
• About $50 in screws, nuts and bolts per printer.  I don't know the exact count of what needed per printer.  Below counts are approximate.
• 50 * 6-32x3/4" socket cap screws to hold the machine together
• 10 * 6-32x1 1/4"
• 10 * 6-32x1 1/2
• 50 * 6-32 washers
• 100 * 6-32 nuts
• 25 * m3x10mm screws to hold the motors on
• Various longer m3 screws for electronics mounts, extruder
• Total: $487.93
• Missing:
• motors, which I already had - expect to pay $14*5 = 70, or 557.9375 for the whole machine.
• Laser cutting cost - I'll be using Nova Labs' laser.
• Probably some little bits for the extruder assembly
• PET tape - my personal bed adhesion solution.  Search Amazon for powder-coating tape.

You could save on most of the bits from McMaster-Carr, but you'd likely be sacrificing quality - same with Fastenal.  Cheaper electronics packages abound as well, and there's no need for a fancy all metal hotend... unless you need one.

Long post.  But a final shoutout to WoodWorkersSource - they sent an extremely amusing shipping notice, so much so that I thought that the plywood deserved its own unboxing video.

New Build: Prusa i3

I've found myself in need of another printer.  Bertha is printing well, and has learned dual extrusion with Marlin, but my Prusa is starting to show its age.

So, I will be building the Prusa i3 - specifically the Graber lasercut version thereof.

I couldn't find a really great build doc - so I figured I'd write one.

Part one: Acquisition is coming soon.