I need opinions on improving my nice ABS enclosure.

Low volume production? Design a PCB to cover all those unused holes in one go, and get it made at say 0.8 mm thickness and glue it on. You don't need any of those tools you mentioned.

Hobby use? Do the same with thin plastic sheet (e.g. a cheap plastic document wallet, doesn't matter if it's flexible) and hand-trim with scissors and glue it on. 

Yes, it is for low volume production.  I have designed 3 PCB layouts for other 3 enclosures with Kicad v10.  Only this one has the extra rectangular hole.

I need the USB-C opening, switch button hole and the light hole.

The main PCB is horizontal to the enclosure bottom.  According to your suggestion, how do I get a PCB which is also vertical?  

Since it is low volumes, why not use a keystone jack cover?  You can glue it in place - either with epoxy or even hot glue.  It should fit the opening perfectly and it's readily available.  You can get enough at a cheap price to play around with modifying them 

Of course, as shabaz said, just gluing a blank on the backside of the opening would be the fastest, cheapest and probably most effective.  It doesn't have to be a flush closure.

Hi  HKPhysicist ,

I often use openings like these as passageways for controls, buttons, switches, indicators, cable management, etc.

You can mount it as a suitable front panel, making it slightly larger all around so it doesn't slip through.

Along the edge of the front panel, you can attach a very narrow strip of sealing tape (soft adhesive tape from a hardware store) to make it moisture-proof.

On the inside of the housing, attach locknuts (glued on) so you can screw the front panel in place neatly.

This makes the opening quite functional.

If you don't have any specific functions planned, you can simply create a blank front panel and attach the nameplate to it.

Best Regards

Gerald

---

This looks to me like the perfect opportunity to buy more tools. If you want a 3D printer then now you need one. 

Not sure what you mean, but I think PCB covers, keystone covers, 3D printed covers mentioned by all, are all viable options to meet the requirement to cover/patch the cutout.

Shabaz means to use a separate PCB as a cover for the hole, not to use the main PCB to cover the hole.

Another option might be to apply tape over one side of the hole and then pour resin from the other side to fill the hole. Once set, remove the tape. You can colour the resin to match the colour of the case before pouring.

 Another option might be to get some thick self-adhesive labels printed and stick them over the hole. You could make this label larger so as to cover the whole end so as to provide meaningful and neat labelling for the holes you are using and cover the ones you aren't.

I also find a cheap option.

I have found that this rectangle is perfectly a RJ45 dimensions 16mm x 13.5mm.

So, I can actually add this cheap cheap dummy through-hole RJ45 socket to my PCB:

https://www.aliexpress.com/item/1005005570284582.html

5 items for about US$2.

Easy to work with and good looking.

Thanks for all the valuable opinions.  

Hey,

This looks like a good choice for low volume production.  Nor sure whether it is a 3D printer?

https://www.aliexpress.com/item/1005005654989723.html