There are four 4mm clearance holes at the corners of the board. You can use M4 screws to attach the board to a panel or an enclosure, make sure to use nylon washers under the screw heads. The mounting centres are 115mm x 92mm, full dimensions are shown in the diagram:
Duet 2 Maestro Dimensions
The diagrams show the mounting hole points in the format X,Y so the bottom left hole is at X=4mm, Y=4mm, the top left is at X=4mm, Y=119mm and so on. The board has 1 additional holes at (63.4,64.3) for mounting the temperature daugherboard.
A 3d model of the Duet 2 MAestro has not yet been produced.
The mounting holes are isolated and not plated through.
- If you mount the board on a metal surface, use standoffs to ensure that the back of the board cannot short against the plate. A minimum standoff length of 5mm is advised, however larger is preferred for better cooling.
- Do not use metal washers under the mounting screws, or screws with large heads (e.g. button head). Nylon washers are recommended. With a metal washer there is a risk of creating a short.
The PCB is designed to transfer heat from the stepper drivers and power mosfets to the underside of the board. Therefore your mounting method should encourage good airflow underneath the board.
If you mount the board vertically, make sure that cool air can enter at the bottom of the board, flow upwards behind the board, and escape at the top. Convection cooling will usually be sufficient, but if you are using high stepper motor currents then you may wish to add a fan below the board to encourage the upward flow of air. Make the spacing between the back of the board and the panel or enclosure large enough to allow a good flow of air.
If you mount the board horizontally then a cooling fan is recommended, especially if there are other heat-generating components in the vicinity such as power supplies, SSRs or stepper motors. Position the fan to blow air underneath the board (optionally along the top as well), especially along the row of stepper driver chips and between the power input and bed heater terminal blocks.
Important! The higher the motor currents you set, the more important it is to cool the board.