Mounting and cooling the board
All Duet variants have 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. The mounting centres are 115mm x 92mm, full dimensions are shown in the diagrams:
Duet 2 Wifi Dimensions
Duet 2 Ethernet 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 3 additional 2.54mm holes at: (53.1,9.1),(56.7,28.7),(81.5,22.) for mounting the Ethernet Module.
3D models ¶
Phil Maddox has created a 3d model of the Duet 2 Wifi hosted here:
Giuliano Moschini has created a model based on the Duet 2 WiFi model for the Duet 2 Ethernet:
On Duet 0.6 and 0.8.5 boards, and pre-production Duet 2 Wifi boards, the mounting holes are plated-through and connected to the ground plane. On Duet 2 production boards, the 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 between the E1 LED and ground.
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. Always use a cooling fan if you run a Duet 2 Wifi or Duet 2 Ethernet above 2.0A motor current.
The Duet 2 Wifi has a built-in antenna. (It is unclear whether the board could be FCC certified if it had a connector for an outboard antenna.) This antenna cannot work from inside a metal box; it must protrude from an opening. Covering it with plastic should pose no problem. Exactly how much the antenna needs to protrude and/or be visible depends on the quality of your Wifi at the printer location.