Some notes I made while assembling a Prusa i3 Wooden purchased from Aliexpress branded “rp3d.com” to make assembly easier.
If you’ve already built and just want to tune your settings. try this Slic3r configuration bundle (unzip the file then in Slic3r, you can use File > Load Config Bundle to load the file which was in the zip), Slic3r version 1.2.6, which has my settings for PLA using both the standard j-head, and cheap-as-chips all metal hotends.
The materials list in the English manual differs in a few ways. Firstly, M10 rods are not used, only M8 and M6. Two M6 for the Z and the rest are M8.
There should be 3 short M8, 1 medium M8, and 2 long M8, these are used for the Y axis bed. I was also supplied 1 M8 at 150mm, I think this is intended to be used as a convenient measuring stick to get the distance between the Y axis supports correct, I couldn’t find any other use for it.
The large washers on the long M8 runner are for clamping the lower frame to the wooden frame so shoudl be nut-washer-washer-nut (took me a minute to work it out what I was looking at there :-/)
Don’t concern with setting the Y motor mount and idler correctly until the moving platform is attached, similarly you will probably need to adjust the spacing of the lower platform when you attach it to the frame, mating it with the frame will give you the correct spacing so just get it approximate for now. Use the longest 8mm smooth rods to set the long axis spacing of the lower bed, don’t fully install them yet just make sure they will fit snugly in their “sockets” if you were to do so (but don’t).
When you mount the Y motor the wires should exit on the bottom inside of the frame.
There were 4 nylock nuts supplied, these seem to be for the 4 M8 bolts on the long axis of the Y bed, but since adjustment may be necessary it might be an idea to install normal nuts temporarily and then swap to nylocks one at a time when it’s all straight (after you have put in the long smooth rods and attached the platform).
The wooden frame order of construction can be improved by
- First insert the square nuts into the nut holders on all the wooden pieces, they are a fairly tight fit so won’t go walk-about on you, easier to do them all at once.
- Build the Z-axis motor mounts first, take note that there is an 8mm locating hole on the tops to take the 8mm smooth rod for the Z axis, these must be on the OUTSIDE (so the left motor mount must have it’s hole on the left, the right on the right).
- Note that for all the wood assembly the “stackup” should be bolt head, spring washer, flat washer, wood, nut. However for attaching the PSU and PCB omit the spring washer because it just won’t fit.
- Check that the flexible coupler on each side has a 5mm bore on one end (to fit the stepper) and a 6mm bore on the other (for the M6 rod), one of mine was incorrectly supplied 5x5 and I had to drill out one end to 6mm.
- Before installing the motors to the mounts, screw in one of the grub screws on the 5mm end a couple of turns, then slide it onto the stepper shaft with that grub screw aligned with the flat, use that grub screw as a stop against where the flat ends to get your vertical position on the motor shaft right. Then tighten both grub screws.
- Assemble the rear supports and front frame, install the top-caps temporarily, we will remove them again later
Now install the bottom bed into the wooden frame, and get it bolted up according the measurements in the manual, again use the longest 8mm rods to check your long-axis distances are correct. Install the longest smooth 8mm rods CAREFULLY through the linear bearings of the build platform (be very very careful not to damage the bearings), then align the rods onto the lower frame. Use a quick-clamp (ratching clamp) or whatever to press the rods down into their sockets. Ensure the bed slides freely. Then you can do the final tightening of the lower frame nits (except the motor mount and idler) and install the zip-ties around the ends of the smooth rods.
After attaching the build platform to the Y frame, to align the motor and pully, first push the platform to the motor end and adjust the motor position so it is in line with the belt clamp on the platform, then slide frame to the other side and do the same with the idler pully. Don’t worry if the belt doesn’t stay centered on the idler pully, just adjust the idler to try and get it so the belt won’t rub on either side of the pully, mine walks side to side without quite touching either side. Idler tension can be added by angling the idler pully downwards.
Install the long 3mm bolt (for contacting the Z axis end-stop switch) into the X axis motor mount now, it’s more awkward to do it later, you should install the X axis end stop switch now too.
Check that the M6 rods will screw through the Z axis captive nuts of the X axis motor mount and idler end, I had to enlarge the hole on the plastic to get through.
The X axis idler end and motor mount end have holes to accept the 8mm smooth rods for the X axis carriage, these are VERY VERY tight. I reamed them out using the supplied carving tools to be able to get the rods in, still tightly but at least not impossible. I think if I was to do again, I might try a 7 or 8mm drill bit to do the reaming.
At this point, you may want to make a slight fix to the hot end especially if you will be printing PLA mainly. The “J Head” which was supplied has a plastic (”PEEK”) part and the hot block end with the thermistor and heating cartridge. The block can be unscrewed from the plastic part (remove the two screws holding the head in place so you can work on it more easily, they just pull out, not threaded), you should then put a wrap or two of plumber’s tape (teflon thread tape) around the threads, and screw it back in tight. Without the thread tape, the PLA has a tendancy to seep through the threads and as it does so it either burns or picks up adhesive off the kapton wrapping around the block and gets a nasty brown colour, then it will drip onto your print. The thread tape seems to have fixed it. But disassembling the hot end after I had put plastic through it was a very tough job, so if I was building another, I’d do it before I used it! Update: the leaking returned, probably I need to retighten it when it’s hot, or get a length of ABS and extrude it through, then it will plug the leak for PLA. In the mean time I’ve modified and reprinted the extruder mount to accept cheap all-metal J-Heads from Aliexpress, which including the heater and thermistor etc are like $6 delivered, it fits the “short” type (direct feed, not the bowden one).
Insert the X axis 8mm smooth rods CAREFULLY into the extruder assembly, be very careful the bearings are delicate.
Insert the 8mm smooth rods for the X axis (now mated with the extruder) into the motor mount end, they should be a tight fit, make sure they go in a reasonable distance and are even.
Insert the idler pully end of the X axis in the same way, the rods should go right through and extend out a few cm, the exact distance will be adjusted later.
Check so see that the extruder assembly can reasonably freely traverse the length of the X axis, check that you don’t have a twist in it which might cause binding. I had to replace one of the LM8UU which was damaged, either from factory or mishandling by me.
Remove the top-caps from the wooden frame now.
CAREFULLY install the Z axis 8mm smooth rods into the bearings of the motor mount and idler end of the X axis, be very careful, again check to see that the bearings on the Z axis rods are smooth and not doing anything very nasty, if so you might as well replace them now.
Take the X axis assembly with the installed Z axis smooth rods and sit it on the Z axis motor mounts, adjust the X axis idler end so that the Z axis smooth rods align with their “sockets” on the top wooden surface of the Z axis motor mounts, slot the top-caps on the wooden frame into place and make sure that the Z axis rods are correctly aligned (don’t screw the top caps in yet), check that the carriage can move smoothly up and down the Z axis now before you install the threaded rods, and again check that the extruder can smoothly move along the X axis.
Remove the top-caps and screw the M6 Z axis rods down through the X axis motor mount and idler end and align them into the motor couplings, try to make sure the X axis is level when supported by the M6. Now you can install the top-caps finally with the top of the M6 rods floating free in their over-size holes (yes this is correct, the rod tops are intentionally not captive so that slight warping is less an issue).
Tighten the grub screws on the couplers to hold the M6 rods. Use your fingers to carefully turn the M6 rods to get the X axis level, don’t worry if you pop-out a nut by over-screwing one side, put a drop of superglue on the outside surfaces of the nut and then screw it back up into the housing.
You can now install the X axis belt. There is no tensioning ability on this so get it right (update: I created a tensioner, recommended to print and install this once you have things running). Mine had two screws in the ends of the belt clamp on the extruder assembly, I think these were just to hold the clamp open during assembly, I removed them, there doesn’t appear to be any way to clamp the belt with bolts lie there is on the Y axis, they just slot into the clamp and stay there. Leave the excess hanging until you are certain your tension is right, I left mine dangling until I had actually fired it up and checked all the axes were controllable.
Install the remaining end-stop clamps and switches as shown in the manual, I would suggest setting the Y axis stop somewhat further forward than the manual because the binder-clips holding the glass down will obstruct the nozzle if the Y axis is allowed to go all the way to the end (the X axis stop is not adjustable).
Similarly set the Z-axis stop higher than necessary for now to avoid accidental damage before you have sorted out your software etc. Note on the Z stop, when you are done with the tweaking, make sure this is properly tight, mine slipped around and failed to trigger because I didn’t do it up tight enough (and had a wonky bearing which was twisting the rod a bit didn’t help).
Install the power supply, the manual shows it with the terminals facing down to the bottom, this is silly, put them facing upwards, firstly the capacitors will then be at the bottom and fractionally cooler, but more importantly, it makes attaching everything much easier. Throw away the (unearthed!) power cable that came with it, just sacrifice one of the good sealed earthed power cables that you probably have a drawer full of. Use crimped on ring terminals for good finish and safety, red pre-insulated ring terminals with a 4mm inner hole diameter fit and appear to handle the current fine. Before you install the 12v output wires, power up the power supply and check the voltage, prevention better than cure, also, remember when checking the voltage, that’s mains power on those screw heads right there near where your fingers are, CAREFUL NOW!
Do not install the PCB onto the frame, get it wired up first, route your wires how you want, cut them to appropriate lengths so that they will reach the connectors when the PCB is comfortably sitting on your desk beside the printer (you probably will want to operate it like this from time to time to debug etc, so make sure you can), be careful to remember that some things move and you need to have enough room for them to move.
Follow the wiring colours and instructions in the manual. The far side (PSU side) Z stepper wires, and the PSU 12v output wires run through the slot on the bottom of the wooden frame support, under the Y axis frame, through the opposite slot on the near side. The wires for the Y stepper run through that slot too. Group the wires as you see fit using the cable sleeves supplied. The extruder assembly wires in their sleeve can be fed through the hole in the top-block on the PCB side, sleeve and all. After installing all the wires I cable tied each group just to try and tidy it up a bit.
Double, triple and quadruple check your wiring, make sure nothing is shorted out, make sure your work area is clean, the moment of truth has arrived, plug her in. After a couple seconds booting, the fan turns on. She’s alive.
Now you can install Repetier-Host, the FTDI drivers as necessary, connect your USB, configure the printer (see rough settings in the manual) and eventually you’ll be able to connect. Use the manual controls to drive your axes around and check everything works. If at first it connects but doesn’t seem to be working, disconnect, and/or hit the reset button, reconnect.
At this point everything is technically working, so it’s over to you to get the Z axis (and if necessary Y axis) end stops adjusted, the bed levelled, and your first print attempted. The details of which I’ll leave to you and google.
For the software side of thing, FWIW, I’m using Slic3r (not the one built into Repetier Host) separately to do the slicing, and then Repetier Host to feed the gcode to the printer. Note about Repetier Host – in Printer Settings, you should have Reset on Connect Disabled.
Here’s also my current Slic3r configuration bundle (unzip the file then in Slic3r, you can use File > Load Config Bundle to load the file which was in the zip) , Slic3r version 1.2.6. The configurations include PLA filament settings for the standard j-head which is supplied with the printer, another for an all-metal hotend but without a dedicated fan on the heatsink (runs the standard fan full speed all the time), and one for an all-metal hot end with a dedicated fan. I modified the extruder mount to accept cheap ($10 US and cheaper) all metal hot ends from aliexpress (with fan and without fan in both cases you want the “short distance” one to fit in my extruder mount).