I have created the following PCB design:
On the right is a USB port, on the left are a number of pads for connecting a round multi-core cable. There will be between 3 and 10 connections, depending on what is being connected. The cable will most likely be soldered directly to the PCB, although a connector could be used. The large number of pads is to allow for different configurations, only 7 to 12 will be used at any one time.
The board is limited to 50x50mm for cost reasons.
My plan is to use a low cost "sandwich" enclosure, basically two acrylic laser cut parts, a top and a bottom, with screws and spacers to hold the PCB in the middle. The case can be larger than the PCB if required.
How can I add effective but cheap strain relief to this design? I was considering extending the case by 10mm to the left, and adding a couple of holes to thread a cable tie though. Alternately I could thread more screws through and bend the cable around them, but that would require more space. Perhaps some kind of slot in the bottom and top case parts would allow a rubber strain relief grommet to be fitted.
This is a hobby project, doesn't need to be commercial grade.