PSU –

– Michel has designed a cover for the 'live' parts that incorporates an IEC socket and switch. Here we see the standard hinged honey coloured cover. Note: Mains Voltage is fed into the PSU, after this all Voltage is 12V or less although current can be up to 30Amps

Tin with solder all the wires to be connected to the PSU terminals to help prevent stray strands of wire causing shorts

• OMC = Open Motor Controller
• HB = Hot Bed

PSU –

– The PSU and Controller housings are mounted onto a base board. This reduces transfer of vibrations from the Printer

Casing the Electronics –

– An 80mm fan is used to cool the electronics, this case made of reused aluminium

Mounting the Electronics –

– With the fan removed we can see the layout of the OMC and two driver boards This photo gives a good view of the IDC flat ribbon cables and the orientation of the connectors with a red stripe down one side. You should also refer to the photo to note how to connect the FTDI cable, exposed pin side to the top and a spare socket on the connector is set to the right. A blanking piece could be inserted into the spare pin if wished.

OMC board –

– Access to the Programming connector, SD Card and Reset button are through a side access panel.

The OMC board is supported on two plastic standoffs at the rear and to the case at the front.

It is good to be able to view the LED indicators mounted on the OMC board

Access to the large chip may be needed in the future to allow for loading new Firmware.

The connectors on the left of this photo are from the end-stop microswitches. The other end of these 2 wires are soldered to the N/O pin set on the microswitches.

Note: It is likely that end-stop switches will be changed to use the N/C pins in the future, to reduce the chance of them picking up interference, but this will need to be accommodated in the Firmware on the OMC

Driver Modules –

– The 2 driver chips on each board are attached to the casing to allow heat to be disappaited

Add jumpers to the headers as shown in the picture, NB The two mirrored header are opposite ways around.

Wiring to the OMC terminals –

– Here we see the wiring to the screw terminals on one edge of the board. On the right is the connector for the electronics cooling fan that is poowerd whenever the OMC is on. Note that the wires to the screw terminals were tinned in a previous step

Connections to Driver Modules –

– Here we see the Extruder Stepper and Z Axis Stepper with the Extruder Cooling Fan connection in the centre. The connections on the stepper shell, when viewed as here from the rear and with the key slot to the top, are coloured Black, Green, Blue, Red, from left to right

Running the Wires –

– The Hot End thermister and Heater wires are run up the front A frame and the Motor wires up the rear frame to reduce interference.

Helpful hint. Buy a pack of 100 cable ties and use them liberally!

Allowing for the Moving Axes

Wrap the wiring to avoid rubbing, catching or stretching of wires

Wiring to the Hot End and Bed

The heating resistor wires are stiff and inflexible so running these avoiding any of the frame can be a be tricky

The wiring to Hot Bed is attached to the Y axis base board with a cable clamp.

The HB thermister goes to a hole in the centre of the HB and should be held 1mm above the bed surface so that if touches the glass printing surface. It is held in place with Kapton tape or Sugru

6 though holes are located on the HB PCB between the wiring points for optional surface mount LEDs and resistor. (How to Mount LED's) You need only mount 1 LED to get an indication when the HB is powered. If one is used then it must be polarised correctly to match the +/- power connections. An alternative is to mount 2 LEDs in opposite polarisation that so that one will be lit irrespective of the way the power wiring is orientated

Note: check the lay of the cables over the full movement of all axes and the full printing envelope