Wiring the KFB2.0 3D Printer Controller




Posted in Technology3D-Printing

Introduction: Wiring the KFB2.0 3D Printer Controller

About: Avid 3D printer builder, currently completing my 3rd printer design. If you like what you see and maybe even implement what provide, consider supporting my on Patreon.com: https://www.patreon.com/Core3d_tech

The KFB2.0 controller is an interesting little board, that caught my attention for it's size and price. It's less than $20 ($18.59 to be exact on Amazon.com: http://amzn.to/2FBSghi ) and about half the size in height compared to the RAMPS 1.4 (Stacked) kit.

It does lack some serious documentation, which is mitigated by the fact that it's basically a RAMPS 1.4 all-in-one on one board. Same 8 bit arduino chip and all the same pin configurations.

It does come with a few extra's like a 5v and 12v dedicated output (RAMPS only has the 12V and you can borrow 5V from elsewhere on the board).

You can also put more juice through the KFB2.0. It can take 12-40volts. Should you choose to go with a 24 Volt power supply make sure your heated bed and hot-end heater cartridge can handle the extra 12 volts.

It comes with 4 power outputs but in all honesty I've struggled (and lost) getting the 4th under control.

If you're deciding to go with the TMC2130 (see my instructable and results on that one here) you'r in luck as the dedicated ICSP connector will prevent you from having to solder on extra pins to share with the card reader.

The other difference with the RAMPS 1.4 is the connectors. the KFB2.0 uses all JST-XHP 2.54 connectors so bring out the crimping tools (or buy proper wires).

Step 1: Parts Required

I have used the KFB2.0 board on 2 of my printers now (on you can find here) and am pleased with the way it operates.

The KFB2.0: $18.59 http://amzn.to/2Gk9qBi

Here's a list of all the items I have attached to the KFB2.0

Nema 17 1.7A (5 pack) http://amzn.to/2E3gvYc

Mk8 Extruder

full direct exturer $36.99 http://amzn.to/2E3gvYc

Extruder Frame only $8.99 http://amzn.to/2FL3hAc

V6 Hotend (12V): $18.99 http://amzn.to/2HoEXS0

For end stop control you can go with two options (I will discuss wiring for both):

The fully wired Limit switch (with cables): $7.98 http://amzn.to/2E3gvYc

The simple Micro Switch: $8.99 http://amzn.to/2E3gvYc

Stepper Cables: $8.59 http://amzn.to/2FHuALR (JSP HX2.54, which fit the KFB2.0)

12V/30Amp Power supply 19.98: http://amzn.to/2E3gvYc

Heated Bed $31.99 (optional but will describe wiring) http://amzn.to/2E3gvYc

Thermistors $8.99 http://amzn.to/2FtRvux

LCD 12864 $14.99 http://amzn.to/2HoEz60

Stepper Drivers $9.99 http://amzn.to/2FKdRYd

Fans. I'm a huge fan of the Noctua Fans. They are a bit pricier but worth the SUPER quiet:

12Volt: $13.95 http://amzn.to/2FDoyss

5Volt: $13.95: http://amzn.to/2p8JZdO

(If you want to go with the TMC2130, I recommend getting the real deal from trinamic waterott through Filastruder.com)

Step 2: Assembling the KFB2.0

Before adding the steppers, add 3 of the jumpers underneath each of the steppers. This will enable 1/16h micro stepping for the A4988 and DRV8825 drivers (not necessary for the TMC21xx drivers)

Adding the Stepper drivers does take some special care. MAKE SURE your drivers are oriented properly. The pins instructions are on the back of the board but I've add an image to show them on top. Your stepper boards should have the corresponding pin names. To keep it simple, align DIR and GND on the drivers to the board.

for the A4988 drivers this means the little pot meter is on the same side as the USB PORT

for DRV8825 and TMC2130 the pot meter points in the opposite direction

Step 3: Wiring the KFB2.0

Wiring the KFB2.0 is very similar to the RAMPS 1.4. As a matter of fact in the Software it is configured as a RAMPS 1.4 configuration. Most of the pins are connected identical to RAMPS.

One of the downsides to the KFB2.0 is that a lot of the useful information is printed on the back of the board. Take note of that before you bolt it on to something.

The first image above pretty much explains it all. Power (12-24V) goes in at the small green connector. Polarity IS IMPORTANT. Make sure positive connects to positive. The rest of the connections are discussed in the next steps.

Step 4: Connecting the Fans

-There are three FAN outputs.

The green connector with the Fan written next to is is the controllable fan that generally is referred to as the parts-fan. It is controlled variably by the software and cools the last layer of filament deposited.

There's a 5V fan output and a 12-24V fan output. It generally connects to the fan that is attached to your hot-end heat sync. This one starts running when you power up the board.

ALL FANS have a red and black wire. Polarity matters, make sure positive is connected to positive.

I'm a huge fan (no pun intended) of the Noctua fans. They are incredibly quiet. They come in both 12 volt and 5 Volt version.

If you have any plans of using auto bed leveling, I recommend using a 5 Volt fan as it will leave the 12 Volt connector for the proximity sensor used in Auto bed leveling.

Step 5: Connecting the Heaters

This boards has three outputs for heaters.

Hot Bed (Heated Bed)

Heater0 (primary extruder)

Heater1 (second extruder)

-The Hot bed and Heater0 outputs speak for themselves. They don't care about polarity but make sure you use wire of proper gauge (14-16) as these carry a lot of Amps).

-Heater1 is not as straight forward. If you have double extruders you should connect the second one to this output but; I have not been able to get it to work. I've tried tracing its pins back to the board but even after doing so I could not get it powered up.

I'll keep you posted if I ever succeed.

For each heater there would be a corresponding Thermistor that notifies the board of the actual temperature.

The thermistor for the extuder connects to TEMP0

The thermistor for the heated bed connects to TEMP-BED

Polarity does not matter for these connections.

Step 6: Connecting the End Stops (Maketbot Style)

If you are using the most commonly used end stops "Makerbot Designed Mechanical Endstop Kit", it comes with little circuit board and wiring. It will light up an LED when triggered.

There are 3 wires coming from the end stop: RED/BLACK/GREEN

IMPORTANT: make sure the wires correspond with the image above.

If you have to crimp your own connectors make sure the RED wire is on the "inside" towards the center of the board.

Reversing the wires I believe fry parts of your board.

Step 7: Connecting the End Stops (Micro Switches)

If you forego the fancy Makerbot Switch (don't do it for the price, it's generally more about the size of the sensor) and instead go with a micro switch it's my experience wiring is a bit easier. You really only need two wires.

Solder the wire to the two outside pins of the Micro switch and connect them to the -(minus) and s (signal) pin on the ramps.

These are the two pins towards the outside of the board

Since in this configuration the connection is open you will have to flip the configuration in the Marlin software to reverse the signal.

Step 8: Connecting LCD

The LCD connects to the two EXP1 and EXP2 connectors on the board via the 2 flat cables that most likely came with your LCD unit. You're LCD board will have the corresponding EXP1 and EXP2 on the back.

That's really all there is to it.

NOTE: Several reviewers for the KFB2.0 have complained that the LCD connectors are on backward, requiring them to cut of the notches from their cables. I won't dismiss this, but I've used 3 boards (ordered on different occasions) and have not found this to be a problem.

Step 9: Setting Up the Software

I won't go into setting up the software in this instructable other than to say that the KFB2.0 runs Marlin 1.1.x and corresponds to the RAMPS_14_EFB.

In your configuration.h select the BOARD_RAMPS_14_EFB if you use a controlled fan and heated bed

// The following define selects which electronics board you have.<br>// Please choose the name from boards.h that matches your setup

Step 10: Conclusion

The KFB2.0 is nothing fancy but it packs more than a traditional RAMPS 1.4 board and comes at a very reasonable price.

I currently have two printers running the KFB2.0 and have had no issues yet (at least not with the board).

On of the printers is fully explained here on instructables.com at https://www.instructables.com/id/3D-Printer-Cantil...

Let me know if I missed something, screwed up something or should add more for clarification.

Most product links are affiliate links so if you do need to purchase some items, please use those links. I'll make a few pennies.

If you would like to the instructables coming consider supporting me at patreon.com. Writing and testing all this doesn't just take time. I have to buy the parts as well. Thank you!!



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    2 Tips


    Sharp observers have found the servo pins missing from this KFB2.0 board. Odd they did that. Should you wish to add a servo actuated auto level probe, Adam from Australia pointed out (Thank you for that) what you can do:

    use pin 57 as signal for the servo and use gnd, vcc adjacent (see image).

    in the pins_RAMPS.h file, replace
    // Servos
    #ifdef IS_RAMPS_13
    #define SERVO0_PIN 7 // RAMPS_13 // Will conflict with BTN_EN2 on LCD_I2C_VIKI
    #define SERVO0_PIN 11

    at the top with:

    after that uncomment

    * Z Servo Probe, such as an endstop switch on a rotating arm.|
    #define Z_ENDSTOP_SERVO_NR 0 // Defaults to SERVO 0 connector.
    #define Z_SERVO_ANGLES {70,0} // Z Servo Deploy and Stow angles

    kfb2.0  servo pins.jpg



    Just what i needed, Thanks! Only problem i see with this board compared to the mega + Ramps 1.4 setup is the lack of servo pins. how would you control a servo actuated auto level probe? getting the power from the 5 volt fan connection is no problem, but what about the signal? the micro switch will use the signal from z Min pin so as i see it thus far this is a big limitation to this board. if i have to but a new type of probe, then i did not ave any money! any help would be greatly appriciated.

    3 replies

    I'm asking around, but would any of the Max X, Y Z connectors not do the trick? Redirect Pin 2 from X_MAX_PIN (pins_RAMPS.h) to whatever servo pin your probe would use?

    Someone else mentioned you could use pin 57 as signal for the servo and use gnd, vcc adjacent (see image).

    in the pins_RAMPS.h file, replace
    // Servos
    #ifdef IS_RAMPS_13
    #define SERVO0_PIN 7 // RAMPS_13 // Will conflict with BTN_EN2 on LCD_I2C_VIKI
    #define SERVO0_PIN 11

    at the top with:

    after that uncomment

    * Z Servo Probe, such as an endstop switch on a rotating arm.|
    #define Z_ENDSTOP_SERVO_NR 0 // Defaults to SERVO 0 connector.
    #define Z_SERVO_ANGLES {70,0} // Z Servo Deploy and Stow angles

    kfb2.0  servo pins.jpg

    the aux1 pin assignment is different from yours, see attached png from the backside


    You are correct I screwed that up. Replacing the image. A3 however equals pin 57.

    Thank you for noticing that

    Hey awesome stuff! Can you please explain how to use the ISCP pins with TMC2130? Thanks

    2 replies

    Please read this reply in conjunction with the instructable on upgrading RAMPS 1.4 to TMC2130 https://www.instructables.com/id/Upgrading-RAMPS-1...

    I kept the pin configuration the same as my RAMPS 1.4 meaning in the pin_RAMPS.h I changed to



    All CS pins are on Aux 2

    I Also did not use the Aux 3 but instead put the ISP connections to the ICSP pins (next to Aux3). I've attached an image with ISP pins and X_CS connected in that configuration.

    Also make sure you install the Bugfix_1.1.x.zip https://github.com/MarlinFirmware/Marlin/archive/b...

    The main release of 1.1.8 did not work (mostly lost steps) the bugfix release did work

    The layout of the ISP on KFB2.0 is the same as the black and white image.

    going by the wires (and colors) defined in the TMC2130 instructable.

    Black to 1/MISO

    Blue to 1/SCK

    Green to 2/MOSI

    Software setup remains the same as the RAMPS TMC2130 setup

    Hope this helps

    ICSP Pins.jpgIMG_8855.JPG

    Thank you very much for such a detailed explanation!

    Nice cantilever builds.

    Thanks for the info on this board.I really couldn't find much.

    Got mine with an 8825 set for$27 from Amazon.

    A budget,pin to pin replacement for a smoked Anycubic Trigorilla on a linear plus.(Stepstick heatsink fell off SOMEHOW?,smoked the board)

    Loaded with the same firmware.

    Seems like a decent,basic board for the dough.

    Initial testing looks promising so far.

    I don't have XH male connectors.
    All dupont on endstops and thermistors on this machine.

    XH pins are a little short with the hood for my liking.

    I gently worked the plastic hoods off the board and connected to the exposed pins.
    The bare pins have the same dimensions as male header pins.

    Extra caution though for polarity sensitive connections.

    1 reply

    Thanks. Clever to take the plastic hoods off. I crimp all my own wires and I go like the fact that they "click" in place but this certainly works.

    Yes, there is. You can add two z- motors parallel but you will be splitting current

    since you'd be using 2 motors for Z you can probably go with the lighter 0.4A (certainly not 2 2.8A steppers)

    Yes, I guess 0,4A would be OK for Z as there are no big accelerations on that axis.

    This is my current setup for auto bed leveling sensor connection on the KFB2.0. I used 2K and 1K resistors which seems to work great. Most other documentation recommends 15K and 10K resistors (just didn't have those around)