help with prusa i3 conversion

i bought a v2 prusa kit from makerfarm which i love, but a week after i got it built they dropped the i3!!!
i love everything except that my right hand side z coupler REFUSES to stay tight, keep having to readjust
i know that having the z motors on the ground should reduce the seperation, working with gravity rather than against it.

i would like to take my hardware, steppers, extruder, board, heatbed, and as much as my threaded rods and smooth rods as i can and upgrade to the i3.

id like to know if anyone has done this yet, and if so whats the parts list looking like, nuts and bolts, and also rod measurements?
also what changes if any would i have to make to the software side, or would all the settings stay the same because its the same size printbed

thanks all

Edited 1 time(s). Last edit at 06/23/2013 04:29PM by jasperash.

I am at the start of the same conversion. Comparing the rod lengths from the i2 page to those for the single plate i3, it looks to me like all the rods for the i2 can be cut down (some don't even need cutting) to make an i3. However there is a catch here. The i3 design calls for two 10mm rods for the Y axis. I have it on good authority that 8mm rods will work instead, but the 10s offer more rigidity. So, if you try to use your 8mm rods in their place, you will have to adjust the Y corner brackets before priting them.

Your motors and controller from your i2 should work. You will have to touch the firmware to atleast make Z longer. IDK about any other changes because I'm not there yet.

Cool, let me know how yours goes.
Rookie question but is there a i3 parts list, measurements page?

on the wiki [reprap.org]

---

Check my rubbish blog for my prusa i3

up and running
[3dimetech.blogspot.co.uk]

Some help in video form: [www.youtube.com]

However, I am not sure the best way to go is to turn your i2 into a i3.

If your is i2 is already working, why don't you find it a new home? If it is not working, you need to learn some skills that will help you building your next printer.

Threaded rods are so cheap that even if you have to buy them all new for an i3 they are still less than $10 all of them (just 1m of M10, M8 & M5).

On the other hand, having a working printer will help you sourcing the plastic parts for the i3.

sorry, I forgot to follow this thread. I'm still working on collecting hardware and printing parts.

[github.com]
[github.com]

That's from the official source of i3. Reading this thing, looking at pics in directory, and collecting up all the parts needed sections is prob your surest bet.

I just did a Prusa I2 to I3 conversion. It seems that nobody has really done a step by step process, so I had to "wing it". I'll give a synopsis here, and if I find time in the next week or so, give really detailed instructions (probably on one of my web sites).

Step one: Get conversion parts. If your I2 is working well enough to make good prints, print the following items, assuming that you plan to use the I3 frame kit that makergeeks.com sells.

X-carriage
X- End Idler
X-End Motor Mount
Y-Axis corners (4 required)
Y-Belt Holder
Y-Belt Motor mount
Y-Belt tenisoner/Idler
Wade Extruder Body for I3.
Fan Dutch

You will reuse these printed items from the I2:

Wade Large and small extruder gears.
end switch mountings.
Extruder idler (the part that presses the filament against the hob bolt)
Platform bushings.

My I2 was not working all that well due to the Z-axis slippage that plagues the I2, so I just bought the printed parts from MakerGeeks.com when I ordered the frame. You will have some duplicate parts doing it this way, but you can pick the best of the duplicates.

You will need to obtain the following additional "vitamin" parts.

20 M3 14 mm screws
20 M3 hex nuts. I used the thin pattern nuts, because that's what I had, but they tend to slip out of place until you get them tightend down while assembling the frame. The "standard" thickness has to be forced in. Pick your poison.
M5 "all thread" rod 0.8 mm Pitch. You will need two pieces at least 30 cm long. I bought a meter long rod and cut off two 32 cm pieces.
2 M5 nuts to mate with the M5 all thread rod.
2 5 mm shaft couplings. I found a seller on Ebay that had them for a very good price.

Step 2. After you have printed the conversion parts if you are not buying them, dismantle the I2. You don't have to unsolder anything, just cut all cable ties so that you can seperate the components and unplug or unscrew them from the driver board. Make a diagram as you disconnect everything paying particular attention to the orientation of the connectors and polairty of the fan connection.

Step 3. Assemble the frame using the M3 14 mm screws. Before you do this, check the fit of your electronics. I had to drill extra holes. Set this assembly aside for now.

Step 4. Assemble the Y Axis base, using the M8 threaded rods from the I2. Use the longest rods for the "Y" direction of the frame. Although the I3 calls for M10 threaded rods, the M8 long threaded rods from the I2 will work just fine.

Step 5. Attach the platform bushings to the new platform frame. Attach the new Y belt holder. You may have to drill another hole in the new platform holder, depending on the style of Y belt holder that you got.

Step 6. Mount the heated bed to the new platform frame using the same hardware that attached the heated bed to the old particle board platform on the I2.

Step 7. Attach the Z axis motors to the new frame.

Step 8. Assemble the X axis parts. First install the linear bearings from the old mounts into the new X axis parts. Then force fit the smooth rods from the old X-axis to the new X-ends. Don't forget to put the linear bearings on the rods first! Critical adjustment here. Make sure that the two small holes in the X-ends that will take the M5 "all thread" liine up exactly with the Z-axis motor shafts, othewise the Z-axis will bind. Tie wrap the new X-axis carrage to the linear bearings. Install the M5 nuts into the X axis ends. They should be a snug force fit.

Step 9. Mount the completed Y Axis base to the new frame. As it turns out, the correct postion is with the threaded rods of the base just touching the supports of the new frame.

Step 10. Install the new X axis assembly. Use the smooth rods that you have left and the M5 "all thread". Attach the M5 all thread to the Z-axis motors with the couplings. Manually turn the motor shafts and check for binding.

Step 11. Assemble the Wade extruder using parts salvaged from your old one. This version does not use the aluminum adapater plate, the hot end fits directly into a hole and is held in place by a couple of M3 X 20 mm screws salvaged from the I2.

Step 12. Attach the Wade extruder to the X-carrage, raising it high enough by manually turning the Z axis motors if necessary.

Step 13. Install the X, Y and Z end switches. You will have to change how the actual switches are attached to the brackets, but it's not that difficult. Have them in the same general location as on the I2 so that you don't have to do as much reprogramming. Tighen the M8 nuts that hold the Y frame to the vertical frame, adjusting as necessary so that the Y travel is centered correctly.

Step 14. Reconnect the electronics. Place the machine at the final location where you are going to use it. Make sure it is on a flat surface.

Step 15. Manually reposition the X and Y Axis to about the mid point. Move the Z axis to give about 10 to 20 mm clearance from the print head. Measure the distance of the X axis top smooth rod from the Z axis motor mount with a digital caliper.
Zero the caliper and lock it. Go to the X axis idler and check the height from the top smooth rod to the motor mount there. Adjust to be the same by manually turning the 5 mm lead screw. Hold the other Z axis motor from turning! Even though the machine is not powered up yet, the Z axes motors are connected in parallel and the one you are turning will act like a generator and turn the other motor!

Step 16. Connect your computer and power up the +12 volt supply. Load Pronterface and connect to the printer. Command the X, Y and Z axies to move 10 mm each direction. Note if they move in the correct direction or not. If not (two of mine
were reversed) make a note of which ones were wrong. Once you have confirmed that everything works again this might be the time to tidy up the wiring with tie wraps.

Step 17. Close Pronterface and open your Arduino editor. Open configuration.h. Scroll down to the"Inverting axis direction" section and change the "sense" of the ones that were wrong. That is, if it was "true", change it to "false" and vice versa. While you are in configuration.h go up to "#define _AXIS_STEP_PER_UNIT" and change the Z-axis. You will need to multply the value that is there by 1.6, since the pitch of the M5 lead screws is finer than the M8 used in the I2. This will get you in the ballpark. The other values should be correct, since you are using the same belts and drives for the X and Z. Finally go to the "Max Length" section and change them to 180 for X Y and Z. Yes, in theory you can do 200X200X200 but that will put the nozzle right at the edge of the glass and the Z axis almost hitting the top mounts. Save and upload. then close the Arduino editor.

Step 18. Adjust the X and Y end stop switches. Load Pronterface and check that the X and Y end stop settings put the nozzle about 10 mm from the edge of the glass. This is not too critical. While you are in Pronterface also set it for a 180x180x180 print area with no offset.

Step 19. Adjust the Z end stop switch. This is critical. However at this time we'll just do a coarse adjustment. First adjust the print bed mounting screws to about their half way position. Move the Z axis switch until it is obviously too low. Use Pronterface to slowly move the Z axis down until it is just touching the glass. Move the switch up until it just clicks. Now try the Z home command. If it presses down on the glass move the switch a couple mm higher and try again. When you get to the point where the hot end is about 1 mm from the glass go to step 20.

Step 20. Home all three axies Use the corner bed adjustment screw nearest the nozzle until you can just move a piece of paper between the glass and the hot end nozzle. Make sure there is no plastic hanging from the end of the hot end from a prior print before doing this. Move the bed to the maximum Y axis and adjust the nearest screw for the same tension on the piece of paper. Move the bed to the maximum X axis and adjust that screw. Finally home the Y axis and adjust the forth screw. These adjustments interact somewhat so repeat it at least once.

Step 20a. If you have trouble getting all four corners to the correct height check for frame warpage as follows. Remove the clips holding the glass. press gently on opposite corners. The glass should not rock. If it does, confirm that the glass is not warped by turning it 90 degrees. If it rocks on the same corners, the glass is fine, but the Y frame is warped. Make sure the machine is on a flat surface 90% of "warp" problems have been traced to a non flat installation surface. Loosen the M8 nuts and allow the frame to settle. Tighten and try again.

Step 21. Z axis fine calibration. Home the Z axis, then move it up 10 mm. Measure the distance from the end switch mount to the bottom of the X motor mount. Move the Z axis up 100 mm. Measure the distance. If you are lucky it will be exactly 100 mm different. Most likey it will not be. Divide 100 by the actual distance traveled. This will be the correction factor to apply in step 23. Unless it is grossly off, we'll fix all the calibration issues at the same time.

Step 22. Print a 20 mm per side calibration cube. Let it cool. Before removiing it from the heat bed, measure the X and Y sides. If you remove it first, it's very easy to lose track of which face is X and which is Y. Divide 20 by the actual size to get the adjustment factor.

Step 23. Close Ponterface and open the Arduino editor. Open configuration.h. Multiply the values in the "#define _AXIS_STEP_PER_UNIT" section by the correction factors obtained in steps 21 and 22 and change to the new values. Save and upload.

The upgrade is now complete. If you desire extreme accuracy, print another calibration cube, but if you were careful the new cube should be within 0.1 mm of actual size.

Edited 1 time(s). Last edit at 11/12/2014 03:58AM by br2600.

Now that I've been running that machine for a few days, it has become evident that the Wade Extruder as suppled by maktergeeks.com MUST have the fan going at all times, else enough heat is conducted from the hot end to soften the plastic extruder body. I kludged mine to reuse the aluminum mounting plate for the hot end assembly.