I3 Plus Frankensteining into a duet

  • Hi all… newbie here. Got my first printer a couple weeks back and have been hooked on modifying it ever since. Talked the wife into letting me buy the Maker Select Plus and i dont think she knew I would start tearing into it like I have been. Hoping to get some validation on some ideas from the great folks here as well to make sure I am not going down the wrong path.
    Original printer: Maker Select Plus 3D
    Thoughts: Good printer but not great. After lots of non stop printing the print bed became warped with a wicked frown. This led me to try and figure out ways of leveling it. I also felt like the extruder was lacking so I replaced it with a Flexion. In my extended research I came across lots of praise of the Duet products and my brain started going crazy. I saw they also worked with a BLTouch and I just had to have one.

    Path going forward:
    I am stripping the electronics out of the 3P and replacing the controller with the DuetWifi. I also ordered and will be using the PanelDue 7i since I couldnt find much in the way of keeping the existing touch LCD without writing firmware, which felt like more work than it was worth. I will be adding some drag chain guides as well for cable management and as mentioned the BLTouch for the Z.
    Eventually I would like to build a CoreXY box with a bigger print area and some better motors, but for the time being this is what I have.

    So.. question 1 should be easy. Will these steppers work ok? Ive seen documentation about the steppers being a minimum of 1.2a and these seem shy of that.
    E/X/Y - C17HD40102-01N - 1.02a?
    Z - C17HD6039-06N - .39a? (seems really low)

    Also I came up with the vref (using the duet's .051 resistors) as:
    E/X/Y - .41616
    Z - .15912

    Now with the DuetWifi its recommended to run the Z in series with the plugs which I plan to do. Other systems they double the voltage to Z so i am guessing that with them being in serial I can just leave it at the 90% of .15912.

    As for the BLTouch I have seen a couple threads on hooking them up so I should be OK there. I will run the wire ahead of time and just not connect them till I have the mount printed. The mount I have chosen will be mounted to the back side of the extruder bearing guide. Id rather have it as close as possible to the nozzle but with the fans and motor, this seems best. Otherwise I have to build a mount for the second blower to mount to the back of the bearing guide and do the BLTouch to the front but that may push it too far forward on the Y.

    Second question is about the speed of the motors after this upgrade. With stock they claimed 150mms which was way too fast for their controller it seemed. I had run normally at:
    Print: 40
    Infill: 50
    Travel: 80
    Initial: 20
    Would the upgraded controller and drivers allow a faster yet still quality print?
    Any other suggestions? I am hoping to start wiring it all up starting next week. I need to get some wire connectors still.

    Oh and I am going to start also designing a "case" for the LCD and DuetWifi. I am thinking I can build it to fit the front of the 3P and mount to the two screws in the faceplate. It will have 2x25mm fans to blow down the back of the Duet for cooling and hopefully it should be only about 70-80mm thick in total, depending on clearance for the LCD so not terrible.

  • administrators

    Those motors will be ok, however I suggest you wire the two Z motors in parallel instead of in series because they are low current motors.

    At those currents, you won't need any fans to keep the Duet cool unless the bed heater draws more than about 15A current. When placing the Duet, give some thought to keeping the WiFi antenna clear of metal parts that would shield it from the WiFi signal.

    The top speeds you can achieve depend on the combination of motors and supply voltage. See the calculator at reprapfirmware.org. If the printer originally used 12V power then converting it to 24V may allow you to use higher speeds, but only if the printer is large enough so that it can actually reach those speeds allowing for acceleration and deceleration.

  • Thanks dc42, your assistance in this forum has been fantastic!

    I like to build my stuff better than worse, so the fans are being built with the future in mind. Hoping that when I go to the CoreXY it will be an easy move, just a change to the mounting plate. The case will also have slots for the WiFi antenna, SD card and reset button.
    Since the original printer is a 24V, its been funky with finding many who have done this conversion if any while keeping the stock parts. With my eye on the future, what are your favorite motors to pair with the DuetWifi? I may just replace the Z's now if they can stay the same size and fit into the gantry. I was thinking of 2 JK42HS40-1704 which would have 1.7A per motor and should fit into the next printer easily.

  • administrators

    Unless your Z axis is especially heavy then JK42HS40-1704 should be a good choice. If you are looking for 40mm long motors then another possibility is 17HS16-2004S1.

  • Those are good too. In fact even though the shaft is a little longer than what I have for the stock gantry they should work too.. I'll order some! Thanks DC!

  • Sounds like you've planned to do pretty much exactly what I've accidentally done...

    Balco Touch (rebranded Wanhao i3 plus also) with Flexion extruder and hot end and Duet Wifi controller and BL touch.

    I ended up with this over time after replacing various broken parts along the way.

    How did you get on with the z steppers? I was under the impression that they'd need replacing with integrated lead screws..

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