Hide cut-out gaps for PCB parts flush with front panel

[physicsben]

I have a PCB in an extruded aluminum case (http://www.hammondmfg.com/1455.htm). I have a few parts that I want flush with the front panel ( ). I can cut holes in the front panel to accommodate this parts, but between machining tolerances and the radius or curvature of the cuts, the holes have to be a decent amount bigger than the part itself. That gaps mean you can look inside the box and see the insides which I'd like to avoid. Any thoughts on how best to do this?

I was thinking maybe some sticky black tape to go around the parts so they are effectively bigger before the part that sticks through the front panel. Or some residue I can paint or. I've found very little part selection of things like where the part is designed to go thorough a front panel hole the body blocks is bigger after that part to cover the hole.

Open to any suggestions. Thanks!

[jpanhalt]

You can get something with a bezel to cover the clearance hole.

I would probably use something with  threaded barrel and nut like these.  That way, you aren't depending on the PCB to support the supply cord.

https://www.digikey.com/en/products/detail/switchcraft-inc/721AFMS/9608573
https://www.digikey.com/en/products/detail/schurter-inc/4840-2200/1212406
https://www.digikey.com/en/products/detail/switchcraft-inc/ST10U/4966994

[mikeselectricstuff]

For rectangular parts and sharp corners, dogboning the corners works pretty well
(Example could be tightened up a bit more, but you get the idea )

[wilhe_jo]

Hi!

Mike's suggestion works perfectly fine (btw. thank's for that video about PCB front panels back then)!

However, you can reduce the visual impact a lot by just cutting to the corner (in the attached image, the circle touches the corner).
You can further blend in everything by adding some arcs (same diameter as the circle) and use some tangent constraints to connect everything up.

Just for the sake of completeness, the circle represents the cutter

If i get it right, 2mm is nowadays the default cutter diameter in basically all PCB fabs.
I stay with 3.17mm just in case I have to do this on my own router...

73

[mikeselectricstuff]

1.6mm is usually the minimum router before costs increase, but 2mm is a good default to use, especially if you work on a metric grid

[Microdoser]

If you don't mind doing some finishing work by hand, I find a square file gets the corners to fit flush with a square connector. Then you can machine the sides to fit flush and just need to do a little filing in the corners to remove the curved material.

If that is not acceptable, there are drill attachments than can drill square holes...

[SMTech]

You don't specify what your endcaps are made from, but assuming your using the supplied aluminium plate, we used to press out D-Sub and DIN apertures using a Punch/Die, this wasn't exactly speedy and they wear out with time. Looks like they may be slightly obsolete (e.g https://uk.farnell.com/c/tools-production-supplies/tools-hand-workholding/punch-tools/hole-punches?punch-type=d-type) these days but there must have been and remain to be other sources of such punches in various shapes. These days we get the enclosure supplier to do it for us as its a single product requirement and we do a years worth at once.

One of those tiny CNC machines should also be able, in combination with a square file, be able to do a slow but vaguely accurate job although as is typical with those types of appliance some jigs and modding are probably needed to get a repeatable zero etc.

[phil from seattle]

Hi!

Mike's suggestion works perfectly fine (btw. thank's for that video about PCB front panels back then)!

However, you can reduce the visual impact a lot by just cutting to the corner (in the attached image, the circle touches the corner).
You can further blend in everything by adding some arcs (same diameter as the circle) and use some tangent constraints to connect everything up.

Just for the sake of completeness, the circle represents the cutter

If i get it right, 2mm is nowadays the default cutter diameter in basically all PCB fabs.
I stay with 3.17mm just in case I have to do this on my own router...

73

Yes, this is a good (though somewhat time consuming) practice.  You also don't have to take the circle to the corner because the connectors generally do not have 100% sharp corners - there is some rounding over.