We are manufacturing electronic instrumentation which comes in a machined aluminium case. We have full flexibilty on design of the case. I need to design some form of strain relief for the single cable, which has a diameter of 6mm. The case needs to be sealed to IP67. I have in mind some sort of glue but not sure what is the best thing to use here - we intend to produce tens of units, so needs to be repeatable and relatively easy to manufacture. What would be recommended here? Thank you
You can use a cable gland. For your use case:
- Select a cable gland which can hold a 6mm cable. These glands can either be made up of metal or nylon, like the "RS PRO PG 7 Cable Gland" or "HellermannTyton NGM M12 Cable Gland". At any rate, these should provide strain relief and at least IP67 rating -- you turn the gland with the cable passing through and the rubber or nylon material inside squeezes on the cable.
- You need to drill a hole larger than 6mm to accomodate the gland. The specific size depends on the gland that you'll be using.
You could just buy a grommet that fulfills your sealing requirements, and fits into a larger hole, and solve the strain relief issue on the outside, e.g. by a screw-on clamp thing.
However, standard way: Sealing Grommet/Strain relief to fasten into a hole:
You don't mention anything about what type of cable this is but for most even vaguely common types of cables, you should be able to use a panel-mount connector. The connector provides strain relief, and you can get them already certified to IP67. A few random examples:
Most companies that manufacture connectors have entire product lines that are ruggedized and already tested against various standards. Installing a connector in a cutout is less manufacturing work than running a cable through a hole and trying to seal the opening with glue or epoxy, plus you don't have to worry about the seal breaking loose over time as the cable gets jostled around. It also makes the device overall easier to package and transport since the cable can be disconnected and stored separately, and discourages harmful practices like winding the cable tightly around the device for storage.