PCB with square ended slots

[Simon]

I'd expect that a slot in a PCB would be routed with a round spinning tool. But can square ended slots be made inexpensively?

[Kasper]

I'm not sure about square end but if you want flat end you could try an 'I' shaped slot

[ConKbot]

Yes, if you're ordering a few thousand+ 1-2 layer boards that get die-cut. Otherwise youre looking at laser routing (extra machine/step so definitely a cost-adder) or adding relief/clearance cuts, which will add a bit of cost if the board house has to move down to a smaller diameter cutter (slower feed for the mill, more time on the machine) though it should be minor if its just a tool change and detailing a few slots.

[Kean]

Only in mass production by creating a punch and die, which generally has looser tolerances than routing and usually is only used for really low cost PCBs.

If you need something with sharp corners to fit into the slot then you can use “dog bone” ends on the slot.  (This is different from the “dog bone” traces used for BGA fan-out)

[IconicPCB]

You can approach a square ended slot by drilling out corners of the notional square and routing in the usual way.

Routing bits come in a variety of diameters and a discussion with your PCB shop is in order. ( We use 1 and 2 mm chip breaker bits to rout slots and shapes).

[T3sl4co1l]

Phenolic boards are often punched rather than drilled.  These are mostly seen in old equipment (~40s to 80s?) made for mass production (~millions qty), with varieties of CEM and FR being more common today.

AFAIK, if you aren't doing more than ~100k of something, you'll be hard pressed to save enough money by switching away from FR-4 to justify the change.

If you need to fit a square object in the slot, you can dogbone the corners to get a better fit.  I did that on a part of my power flashlight,



Tim

[Simon]

OK no square slots and a complete change of plan I was hoping to just join two PCB's together and solder them at right angles to each other but use a PCIe card edge so that I had the option for being able to insert into a regular socket. I think i will just use pin headers. That way I just choose if i want the socket or if I just insert the header and solder straight on.