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GRBL Control Board Strain Relief

control board strain relief

Depending on your model of 3D printer or desktop CNC, you can benefit from adding a 3D printed control board strain relief. Here’s why and how.

Lots of us build machines using a small printed circuit board controller. You can quickly recognize examples of this approach using Arduino and many Chinese control boards with lots of connections. Usually, you connect wires to header pins, and often USB and Power connectors.

Normally, these pins and connectors are just soldered to the PCB. Often, these boards use surface mount connectors, sometimes, through hole. If you need to connect and disconnect often, these actions put a lot of stress on the PCB. And, if your cables need to move around and stretch, more stress.

An example of these stresses is the Z axis zero probe you can use when milling a PCB. Basically, you connect one wire to the copper plane and the other wire to the milling tool. Your CNC will then make a series of probes touching the copper at various locations. When the probe touches the copper, an electrical circuit is closed and the control board automatically measures the height.

Watch this video demonstration of Z axis probing.

If you just attach the probe to the flimsy pin headers on your control board, after a while the pins will bend and often simply break. Not good.

GRBL Control Board Strain Relief Solution

We can easily solve this problem with a bit of 3D printing. Shown above is my little gizmo to provide control board strain relief for power, USB and probe connections.

My small plastic bracket attaches to the aluminum extrusion, and provides guiding slots for the power and communications cables, shown above right. Proper positioning of this bracket prevents any movement of the connecting plugs at the control board.

Also, you can see above left how I have brought out the connections for the Z axis probe to the front of the CNC. Again, the probe cables do not provide any stress on the control board at back.

Designing, printing and assembling your own version of this control board strain relief solution is pretty easy in any CAD program, as long as you make good measurements. For my Z probe connection, I have provided both banana terminals and 3.5 millimetre phone jack. You can modify to suit your needs.

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