Updated design! With build instructions!

I've put all the files for an updated i3 on my Github: https://github.com/paenian/i3_parts

Including updated build instructions, with many pictures: https://github.com/paenian/i3_parts/wiki

The instructions are a work-in-progress, and take you from parts to working printer.  You'll need to source and cut the files yourself.

Notable improvements:

• Fully braced top frame
• Y endstop now lives inside the printer
• LCD is up top - shortens the cables required, should let you use the factory supplied cables
• electronics and power supply mounting holes are in there
• More zip tie slots for wire routing
• Half-decent instructions in a wiki!
• Feel free to update and improve the wiki.
• Unfortunately, the wiki doesn't easily let you upload pictures - I'd like to have them all internal, not linked to other sites - so please let me know if you add pictures, I'll copy them and host 'em on github.

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.

Updated Hotend Effector

The hotend effector has been updated - here's the skinny on why and how to build the new version.  It requires new rail effectors as well, however the only change there is the width of the rods - the build instructions are identical.

Improvements:

1. The new effector is much more compact.
2. Much higher torsional stability
3. Integrated Z-Min endstop (Experimental!)
4. One fan per hotend
5. Simpler hotend clamp
6. Black.

Vitamins

• 3x M5x20 socket cap screws
• 3x M5 washers
• 3x M5x40 socket head cap screw - make sure it's got a smooth part on it
• 3x springs that'll fit around an M5
• 6x M5 nuts
• 1x M3x20mm screw
• 1x M3 nut
• 1x M3 washer
• 1x M3 spring
• 1-3 30mm fans
• 1-3 hotends (pictures are using the e3d hotend.  It comes with 30mm fans, but they're not great.  I used some old ones that blow harder)
• 1 tactile switch (digikey or just ask, I got a bunch of extras)

RepRapped Parts

• Hotend Effector (https://github.com/paenian/bertha/blob/master/hotend_effector.stl)
• Tripleclamp (https://github.com/paenian/bertha/blob/master/tripleclamp.stl)

Assembly

1. Take the Tripleclamp first.
2. Insert the M3 hardware into the center hole - nut into the nut trap, washers and springs above:
3. Insert an M5 nut into all three nut slots, then loosely screw in the shorter M5 screws with washers.
4. Take the longer M5 bolts and springs, and drop in through the top of the tripleclamp (the top is the shiny part).  It should be a semi-loose fit.
5. solder two of the switches leads, on the same side - you'll need to bend them sideways to get it in the hole, and also bust off the other ones.  Make sure to test the switch - if you pick the two wrong contacts, it'll be always shorted.
6. Insert the switch into the hotend effector, wires through the holes.
7. Insert the three long M5 bolts down into the hotend effector itself.  There are three nut traps inside the side holes, hidden away.
8. Tighten lightly.

And there you have it.  Hotends can be inserted now, as well as fans.  If you use the E3d hotend, well, the fans don't fit in their slots - but you can hot glue 'em in just fine.  Wire it up, and let 'er rip!

I am currently stress-testing this setup - running some long prints to shake it down.  Next step is activating the Z-Min endstop, but that'll be another blog post.

Metal Rod Ends

The Igus rod ends are too stiff to use - they were causing all sorts of binding issues.  I tried running the machine in circles for three hours, and even talked to some IGUS engineers.  Their advice was to use 3 in 1 oil to lubricate, but this also failed.

My solution was to order metal rodends from AliExpress.  Along with this I redesigned the rodend mounts, and shortened the arms slightly (400 to 375) because the metal rodends have a bit more travel than the plastic igus ends.

Vitamins:

• 12* Metal Rod Ends - M5 female socket, M5 hole
• 6  * M5 Round cap screws, 20mm long
• 6  * M5 cap screws, 10mm long (leftover from v-rails)
• 6  * M5 washer
• 12* M5 nut
• 6  * 245mm Carbon Fiber Square Tube, 8mm OD, 6mm ID

RepRapped Parts :

• 12 * Rod End  (https://github.com/paenian/bertha/blob/master/rod_end.stl)

Tools :

• 3mm Ball-end hex key
• Knife for part cleaning - exacto or similar

Note that the rods are short enough that you can cut the ends off of your old rods and re-use them.  Also, if you buy the meter-long carbon fiber, you can now get 4 arms per meter instead of 3 - slightly more economical.  Ideally, the rods should be as short as possible - in order to maximize build height.  Using rod ends, this is about as good as it gets - to do better you'd need 12 universal joints.  I've toyed with designing my own u-joints around M5 bearings, but the size is an issue.  I might do more u-joint work in the future sized around M3 bore bearings, but this is as good as it gets for now.

Assembly:

1. Glue the rod ends onto the rods.  Note the cool 45 degree rotation... designed so that they'd print better, no other reason.
1. Once rods are inserted into rodends, arrange hole side up between a clamping surface.
2. Clamp 'em down.  I'm using a cushion to insure that every rod is inserted all the way.
3. Drip one drop of superglue into each rodend.
4. Let dry.

 Next is simply tightening nuts and bolts.

1. For the first end, the sequence is:
1. M5 by 10mm bolt
2. rodend plastic
3. M5 washer
4. metal rodend.
2. Tighten it all down, keeping the rodend planar to the bolt insertion hole.
3. For the second end, the sequence is:
1. M5 by 20mm bolt
2. M5 nut
3. M5 nut
4. Metal Rodend
4. The reason for the two nuts is for fine length adjustment.
1. The second nut locks against the metal rod end, holding it at a certain distance.  This should be adjusted using a gauge to ensure that all rodends end up being 375mm long.
2. Once the length is adjusted and locked in, tighten the first nut against the plastic to keep it from rotating/shaking.
5. Repeat these steps for the other six rods.

Important:

Installing these rods is exactly like installing the other ones, but you should ensure that the bolt insertion holes are facing outwards - that way you can tighten the rodends or adjust their length without dismantling the entire bot.

Calibration!

I've been working away on the printer; figured I should write up the calibration routine, mostly so as I don't forget it.

This is assuming Repetier Host and Repetier Firmware.  The same techniques work with Marlin and Pronterface, but you'll need to modify the variable names a smidge.

Printer Height

1. Set the Z max length.  Mine is 449.65
1. First set the Z Max to higher than your z (in eeprom or firmware).
2. Home the printer, dial M114 - this should spit out your Z_MAX_LENGTH exactly.  If it doesn't, check that the most current firmware is on there, and that the eeprom values match.
3. Lower the hotend - either send G0 Z100 down, or click the Z Down.
1. Repeat until a piece of paper can just slide underneath the hotend.
4. Send M114 - it should be X0 Y0 Z<value>
5. Your Z_MAX_LENGTH is the old Z_MAX_LENGTH minus the current Z<value>.
1. Write this into the firmware.

Ok, so now you've got the max height down, except for now it's just a convenience.  We'll be adjusting it again after we

Level the Build Plate

1. Your plate has leveling screws; the next step is to make sure that the plate is parallel to the plane of the hotends' motion.
2. In Repetier, set up four gcode scripts
1. on the right hand pane, select the 'gcode editor' tab.
2. From the dropdown, select 'script 1'
1. Script 1:
1. g28;   //home the printer
2. g0 f8000 x-133 y0 z10  //move to one of the towers
2. Script 2:
1. g28
2. g0 f8000 x56.5 y97.86 z10
3. Script 3:
1. g28
2. g0 f8000 x56.5 y-97.86 z10
4. Script 4:
1. g28
2. g0 f8000 x0 y0 z10
3. Each script will move the hotend 10mm above the print surface; 1-3 form an equilateral triangle near the bed adjustment screws, and 4 is the center.
3. Run Script 4.
1. Lower the hotend manually 10mm - it should be just touching the bed - if not, adjust your Z_MAX_LENGTH until it is.
4. Run Script 1.
1. Lower the hotend manually until it touches the build plate.
1. If it touches at zero, congrats!  You're level.
2. If it touches above zero, increase PRINTER_RADIUS
3. If it touches below zero, decrease PRINTER_RADIUS
2. I had to add 5.25mm to my printer radius.
1. I did this 1mm at a time, recording the height each time.
2. When it stops improving, go .25mm the other way.
1. I think 1/4mm accuracy is fine, but feel free to go farther.
3. Note that PRINTER_RADIUS isn't in the eeprom - you'll need to set it in firmware and then reload the firmware.
5. The Z_MAX_HEIGHT shouldn't change during this process, but it's always helpful to check and record it every cycle - it ensures nothing odd is happening.

At this point, you should be able to print anything!  Next post will be about checking dimensional accuracy, and I promise to throw some pictures in.