Thursday, September 5, 2013

Extruder wiring connections (Mendel90)

I'm building a Mendel90... A dimension of the prescribed design utilises a ribbon cable to bring power to the hot-end, extruder motor and fan(s) and carries the hot-end thermistor reading back to the printers motherboard.

The Kit version of this printer, designed and sold by Chris (Nophead), has quite an involved connector assembly between the x-carriage and the ribbon cable that connects to it. In scratch building the Mendel90 I came at this connector fresh and have gone with my own take on it, though the essence of the design, a ribbon cable to the x-carriage, is maintained.

I've built a functioning prototype using various connectors from my junk box. I'm using the screw-down connector for heavier wired hot-end power, and simple push-on connectors for the motor and fan(s). The under side has a spaghetti of wires soldered to the various pins.

 Two longer bolts replace the motor bolts, allowing the connector block to be mounted on to the back of the stepper motor. A piece of plastic is placed between the board and motor for extra insulation on my prototype.

You can mix and match connectors to your own preference. The screw-down ones are definitely a good idea for power to the heavier duty wiring on the hot-end, and multiple strands of the ribbon cable are needed to carry power to it. The push-on connectors are fine for fans. The 16 pin ribbon connector might do with some kind of retaining clip to prevent it working loose when printing. We'll see how it goes!

I don't have access to PCB etching or any way of producing a more professional PCB connector block, so this is probably as far as I'll take this idea. I'm happy to share it so others might evolve it if they wish.

There's lots more to blog about with the Mendel90 build. This is just to get things moving again!

Thanks for viewing!


  1. This looks great. I really like the simplicity of your design. I'm in the process of building a Mendel90 and I'd like to use your board. Do you have a Fritzing or Eagle PCB schema diagram of your board?

  2. Sorry Eden, nothing so elaborate. Just sketched out the connections on a piece of paper, got some strip-board and the soldering iron out. Chris does sell an Extruder PCB connector board (bare or with components) for very reasonable money. Second part of this post:,196585
    Also, if you want to consier speed control of the cooling fan then you may also want to take a look at this later post:,196585
    Best of luck with your build.