Introduction
Before upgrading your Prusa Mini with the Revo Micro please read the following safety cautions
This is a complete upgrade guide suitable for an original Prusa MINI+ and Revo Micro or Revo Prusa Mini Edition. Please note, your printer may vary from the one illustrated in this guide, depending on the model and your own upgrade choices.
You should read through the whole guide before attempting the upgrade to ensure you understand exactly what is required to successfully complete it. The upgrade should take approximately 1 hour.
The upgrade has been carefully designed to reuse the existing fixings on your Mini. This means you will not need to buy any additional nuts and bolts to complete it.
No Firmware changes are required for this upgrade.
Preparation
To begin, you need to make sure you have this part printed in advance:
Do not begin disassembling your printer until you have printed this part or you risk being unable to complete the upgrade!
In order to make the upgrade as straightforward as possible, the part is attached by threading directly into the plastic. This is sufficiently strong and it means you will not need any additional fixings. This version is shown in the illustrations and is the default option. Alternatively, if you want a stronger connection, we have also provided a second STL with slots for M3 square nuts.
Models available here:
https://www.prusaprinters.org/prints/151007-prusa-mini-upgrade-v2-e3d-revo-micro
Make sure you check the tolerances of the printed part before beginning the upgrade. The M3 screws should easily thread into the plastic and (if you are using them) the square nuts should slide into place. It's also very important that the Revo micro can be screwed into the plastic thread.
Suggested print settings:
Recommended materials: PETG, ABS, ASA, Nylon, PC blends, etc. should all be fine. Avoid PLA!
Print with the E3D logo facing up as shown
Supports will be required. Presliced Gcode and a support enforcer STL are provided.
0.4mm nozzle or smaller, 0.2mm layer height or lower
40% infill
3 perimeters (walls)
5 top/bottom layers
You may also need to print:
You will need to reuse the cable management arm on your existing Prusa Mini. If you need a replacement or want to reprint it in another colour scheme, you can find the original STL here:
https://www.prusaprinters.org/prints/57214-mini-printable-parts/files
If you have an early release of the Mini, you may find that yours doesn't use the cable management arm or potentially has the older version of the Minda holder. MINI+ superseded the MINI, but the printed parts are reverse-compatible. Just download and print them from the link above. The files are named fan-spacer-clip and minda-holder.
To undertake this upgrade you will need:
- 2.5mm hex key
- Flush cutters/cutting pliers
- Adjustable wrench/large pliers
- Utility knife/tube cutter
- Small flathead screwdriver
- A handful of cable ties
- Your 3D printed bracket
- Your existing Prusa Mini
- Revo Micro 24V variation (Please double check your own voltage, all original Prusa Mini's are 24V).
- (Optional) 2 x M3 square nuts
Check out our blog if you are unsure on whether you need a 12 or 24V Revo Micro:
https://e3d-online.com/blogs/news/12v-vs-24v
Before starting disassembly, you should make sure your Mini is on the latest firmware from Prusa.
Please see: https://help.prusa3d.com/en/downloads/
Disassembly instructions
Move your extruder to roughly the centre of your bed and around 100mm above the build plate before starting the upgrade, this will give you easier access to the extruder.
You should also ensure there is no filament loaded and that the printer is unplugged from the power source before starting.
You should also place a cloth or piece of fabric over your heat bed to give it some protection in case you drop something onto it.
1. Use the 2.5mm hex key to remove the screw holding the part cooling fan in place and then carefully twist the fan upwards as you remove it. This will help ensure you do not strain the wires.
It is a good idea to keep your screws in a small container while you are working on the printer so that you don't lose them!
2. Loosen the upper fitting and remove the Bowden tube from the HotEnd. You can use a wrench to get a better grip on the fitting.
3. Remove the screw that holds the cable management arm in place. Remove the arm and set it aside, you will need it later.
4. Remove the screw that connects the pinda arm to the heatsink.
5. Remove the screw that sits underneath the fan.
6. Remove the screw above the fan which holds the heatsink.
The whole HotEnd assembly will now be loose, so be careful.
7. Now with the HotEnd assembly loose, you can remove the final fan screw. You can leave the fan where it is, as we will be reusing it in the next few steps.
8. Start taking the heater and thermistor out of the cable sleeve and place the Prusa HotEnd on the heatbed for now, we will handle the wiring later.
You should also cut the cable ties holding the sleeve to the x-axis now.
Assembly instructions
9. If you haven't done so already, thread the screws into the printed part and then back out. At least once for each hole on the part. This will physically create the threads and make the part easier to attach to the carriage. If you are using the square nut version of the STL, you should slot these in now.
It should be easy to screw them in and out, if you're finding it difficult, the hole is probably too small and your printer may be over extruding.
Be very careful not to over thread the fan mounting holes as you risk cracking the printed part.
10. Remove the Revo Micro fan and then thread the Revo Micro into the printed part. You can remove the nozzle and unclip the HeaterCore before you do this if you find it easier.
You should be able to thread it sufficiently tight with just your fingers. Just make sure it feels secure and not loose/wobbly. A good check is to see whether you can unscrew the nozzle without the heatsink moving.
11. Position the mount and make sure the HeaterCore wires are orientated through the gap under the fan, like so:
12. Once in position, secure the mount to the carriage.
13. With the Revo Micro secured, now we must reattach the Bowden tube. You can cut the existing tube as shown here, but you may wish to use a fresh piece of PTFE tubing if you have some spare.
If using a fresh piece you will need to add a brass olive from your Prusa Mini spares bag to one end of the tube. The tube should be around 300mm in length.
Cut the tube just above the brass olive:
Try to cut into the tube as straight as possible and make sure the tip of the tube is circular and not squashed. Rework it back into shape if needed. You can use a scrap of filament to make sure it isn't squashed. The filament should pass through easily.
14. Remove the collet clip and feed the Bowden tube into the top of your Revo Micro. Replace the collet clip once the tube is in place.
Wiring
15. Now you just need to swap over the heater and thermistor wires.
Start by plugging in your extension cables as follows:
The colour of the HeaterCore thermistor wire has recently changed from white to blue. If your HeaterCore has a white thermistor cable. Please refer to the diagram below.
16. Remove the screw holding the mainboard housing together and remove the top covers.
17. Remove the old heater and thermistor wires from the sleeve all the way down to the board.
Then route the new extension cables through the sleeve all the way down to the board.
18. Next you need to swap over the heater and thermistor.
At this point, you should still have the old heater and thermistor plugged into the board.
The illustration below shows the location of the terminals but if in doubt please refer to Prusa's documentation.
Unplug the HotEnd Heater first. The whole terminal should pull away.
Unscrew the Heater connections from the terminal using a small flathead screwdriver and replace them with the Revo Heater extension cable (black with red ferrules). Then plug the terminal back into the board.
Don't worry about mixing up the heater wires, heaters don't have a polarity.
Then, unplug the thermistor. You will need to press on the small tab on the side as you pull to release it. Replace it with the Revo thermistor.
If using the standard extension cables, the thermistor cable doesn't have the same orientation tab as the original cable. Thermistors do not have a polarity though, so you can plug it in either way around.
19. Tidy up any excess cable using cable ties and close the housing.
20. Slide the cable management arm into position over the wiring loom and secure it using an M3x20mm screw.
Make sure the wiring isn't obstructing the carriage when at max position on the X-axis (180mm).
21. Move the Toolhead to the end of the X-axis and make sure there is sufficient length in your wiring loom and bowden tube.
22. When you have sufficient slack, reattach the wiring loom to the gantry with some cable ties.
23. Reposition the fan and secure it with the remaining M3 x 20 screw.
Final Calibration
24. Plug in and turn on your Prusa Mini. Click on 'Calibration', then go to 'Self test'.
Please note, when heating up your Revo for the first time, you may notice small amounts of smoke coming from the nozzle. This is just residue burning off and is nothing to worry about.
Wait for the test to finish.
25. If the test is successful, head over to 'Calibration' and click on 'First Layer Calibration'.
Run through the calibration.
When prompted, make sure you select 'NO' and use the default value (0mm). Your old offset could cause the nozzle to collide with the bed.
You may need to adjust the physical height of the Pinda Probe if you find that the nozzle is still too high when at -2mm on 'adjusted z height'.
If you are struggling to get a consistent first layer. You should rerun your mesh bed levelling in the calibration menu.
PID tuning the Mini
Prusa recommends not to PID tune the Mini (Source here) and the auto PID tune command that is present on the MK3 is not available. Without custom firmware, you are also unable to save to EEPROM.
If you feel the need to PID tune your Mini you can use pronterface and then add your generated PID values to the start G-code of your slicer.
That's it! Your Prusa Mini is now upgraded to Revo.
With the upgrade complete, why not print a fancy holder for your new Revo Nozzles?
https://www.printables.com/model/159519-prusa-mini-bracket-revo-connect
