Ever want to put your Prusa MK3S extruder on your Ender 3 or CR-10? Now you can. You get the best of both worlds in combining cheap chinese frames with a world class direct drive extruder.
- Integrated filament sensor
- Bondtech Gears
- E3D Hotend
- Low Weight
- Easy to maintain
FIRST VIDEO: https://youtu.be/zSFvH2H0kGU
Biege Benchy: First print, no real tuning or calibration put into it except for extruder. The extruder steps are 140 per mm for the bondtech gears.
Gray Benchy: Sliced using Prusa Slicer 2.0 using default MK3S settings The only thing I changed was I removed zhop, all else remains default (except start GCODE, removed firmware version announcement and changed bed level to G29).
VLOG #1: https://youtu.be/APyHX3tR5OE
So, I added a few things after printing 100 or so hours.
1.) Steel V-Slot rollers: https://www.amazon.com/gp/product/B07DS3S678/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
2.) Dual Z lead screw: www.thingiverse.com/thing:3451260
Lesson Learned: Polycarbonate V-Slots aren't enough to hold up to the weight over time. White powder began sloughing off in the first 20 hours of printing.
Also, this project bore unexpected fruit; I was able to use GCODE created with Prusa Slic3r using the MK3S canned profile for PLA and all of the goodness for the MK3 came with it. The zhops are flawless, and the speeding through infill cut print time down significantly. Best part is, I don't have to re-slice all of my production prints. Just drop Prusa GCODE and go. I have to admit, there is something very gratifying watching an Ender 3 zip around like a Prusa and perform flawlessly!
And misc. 40, 25, 7, and 10mm cap screws. This mod is for experts and crazies only, as you'll have to:
- Add raspberry pi (filament sensor, or you can replace OEM sensor with MK3S wires no problem)
- Adjust firmware for thermister type, steps per mm on extruder, adding BL touch/ABL sensors
- Extend Extruder Motor Cable
You can recycle the motor from your old extruder but it is a bit on the heavy side. You might want to try a pancake style motor, but I did find the smaller motors get really hot.
Print all parts in PETG, preferably with a prusa if you have one. I included the GCODE for the mounting plate as I needed to put down a support blocker to keep from filling the zip tie anchor points. All other parts print without supports at .15LH and 20% infill.
I included a .mix file that opens with meshmixer so that you can see the tolerances and fit of the entire assembly on the CR-10 and Ender 3.
I extended the top cover insert so that a PTFE tube can be used as both strain relief for the harness as well a healthy redirect for the filament so that you can still side-spool if you want to.
1 - CR10_Mount_Rev_L: My design for the adapter mount
2 - MK3S_Extruder_Body_Rev_B: Modified Prusa design, added recesses to fit CR-10 10 mm mounting cap screws
3 - MK3S_Extruder_End_Plate: Modified Prusa Design, added 7mm counterbore on top of the existing 7mm to allow 40mm screws to thread into Rev J mount
4 - fs-cover_Rev_B: Modified Prusa Design, added 4mm recess for bowden tube
-All other parts remain the same for Prusa MK3S download package
Update 5/20/19 - Added ABL sensor mount, see file "MK3S Extruder Body Rev B - ABL Sensor.stl"
Update 5/22/19 - I have all of the initial settings uploaded, and a Marlin is working the way I want it to. That said, there is an EMI issue between the extruder stepper motor and the filament sensor. I'm going to try a few things to eliminate the issue:
1.) Clamp on EMI filter
2.) Twisting the wires from the extruder
3.) Placing a capacitor between the + and - terminals
Update 5/24/19 - EMI issue was fixed, a 36mm x 22.5mm clamp-on ferrite bead did the trick. You have to give it 2 full wraps sonewhere close to the pi. Also, I routed the filament sensor direct to the harness vice through the body (original prusa design). I'll link the ferrite bead in the BOM.
Also: I wound up switching to a 42-34 Stepper motor for the extruder for the reduced weight.
With the filament sensor functional, I'm down to little tweaks to the slicing settings but I'm calling this project DONE!
Update 5/25/19 - Added BL Touch adapter for mesh bed levelling. Tested & verified, uses Prusa PINDA mount for adjustable height.
I have run a few test prints, and I'm really happy with the project overall. I rev'd the mount one last time to reach out and grab the screw hole on the Ender X carriage, last rev will be rev L. At this point, I'm going to run a couple hundred hours against it to post wear/tear lessons learned, but I'm done tweaking and I'm freezing the design.
In the end, between the additions of the BL touch and WhamBam flex plate, I think I've only saved about $359/machine as compared to just buying Prusa MK3S kits. I still get the power Panic from Marlin, but not the Einsy board or the Trinamic drivers with the Prusa. All in all, this project represents a cost savings of $5,744 in upgrading 16 Enders to become...... PrEnder 3's!
100 hour lessons learned (6/1/19)
- You can use Prusa Slic3R (change dimensions of the machine) and all of the presets work. This is a huge benefit as Prusa Research has invested a lot of time/tuning into their material profiles, so you get Nylon X, PET, TPU, all pre-optimized when you switch to their extruder. I found the GCODE I have for the MK3/MK3S can be dropped directly into the ender without issue.
- Dual Z is a must!
- Steel wheels on the X carriage are a must to counteract the weight of the extruder. It will wear off the anodization of the gantry, but that seems to be about it.
- The wire loom needs protection against abrading on the top anchor point. I used a couple wraps of electrical tape and that seems to have fixed it.
- Polycarbonate wheels on the Y axis are a great benefit, especially with the faster travel moves that are directed by the default Prusa Slic3r profiles.
- I wound up switching to 42-40 Steppers for the Z axis and Extruderr as the smaller motors got too hot for my comfort. For Z this presented a problem as the mounting holes were tapped, so I created a T-nut based Z motor mount to give the height needed as well as the throw for the alignment to the dual-z design. Refer file "T Slot Motor Mount Rev B".
Mount update 6/11/19
Rev J Mount - Use for those printers that only have 2 holes to mount the microswiss hotends, but not the 3rd hole to the left to secure the shroud
Linear Rail Mod:
Use the "CR-10 Mount Lin Rail Rev A" to mount to the linear rail. This is what I settled on in my final prototype, and I ditched the x carriage wheels altogether. I had to reposition the x limit switch as a result, see file "X Limit Switch Mount Rev B".
You can pick up a cheap bolt-on linear rail here: https://www.amazon.com/gp/product/B0762MPVN3/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
Rolled in TeachingTech's electronics enclosure design along with my own remix of an added bed chain: https://www.thingiverse.com/thing:3688967
It doesn't improve print quality so much as cleans up the overall look of the machine, and pulls it that much further away from stock.
Removed Bed leveling: This wound up being a feature for feature's sake. With the WHAMBAM plate and polycarbonate wheels, there is ZERO disruption to bed level after print removal. I don't want to add probing overhead (time per print) and another part to go wrong for no real benefit.
At this point, I'm calling the complete design finished and ready for rollout to my Ender farm. I have 2/16 machines modded, with a plan to do 1 a week until the farm is finished.
END OF LOG, PROJECT COMPLETE