I have a milling machine.
Max speed around 2000rpm.
I'd like to mill slots for component lugs in FR4 PCBs or stripboard.
Has anyone done this and can advise cutters & techniques to avoid the cutter jamming or breaking?
Max speed around 2000rpm.
I'd like to mill slots for component lugs in FR4 PCBs or stripboard.
Has anyone done this and can advise cutters & techniques to avoid the cutter jamming or breaking?
Normally use carbide tools for FR4, and they will wear out (HSS will wear very fast on glass fibre)... End mill with short cutting section to maximize stiffness is appropriate, you only need a few mm cut depth after all. I suspect 2000rpm will limit the feed rate considerably from what's possible - carbide isn't the toughest material so you need to keep the side forces moderate, perhaps using multiple passes.
There are PCB milling machines out there. They use cutters with 1/8" (or 3 mm Ø) shank. Maybe grab some of those cutters.
Example: https://www.kyoceraprecisiontools.com/pcb/end-mills/
Tom
Example: https://www.kyoceraprecisiontools.com/pcb/end-mills/
Tom
I tend to use cutters like this. I have 5400 RPM in my machine and they do a pretty good job
https://www.amazon.com/HOZLY-Titanium-Coated-Milling-Cutter/dp/B073RJ3SYZ
Not this specific listing, but the same type of cutter
They are cheap and tend to last longer and not clog up as bad as regular endmills. With only 2000rpm you probably need to feed fairly slowly, but these burr type cutters have more teeth and tend not to bind and snap as easily. And when they do snap they're cheap. The finish they leave is pretty good in FR4 but will leave a slight raised burr if you are going through an area with copper.
https://www.amazon.com/HOZLY-Titanium-Coated-Milling-Cutter/dp/B073RJ3SYZ
Not this specific listing, but the same type of cutter
They are cheap and tend to last longer and not clog up as bad as regular endmills. With only 2000rpm you probably need to feed fairly slowly, but these burr type cutters have more teeth and tend not to bind and snap as easily. And when they do snap they're cheap. The finish they leave is pretty good in FR4 but will leave a slight raised burr if you are going through an area with copper.
That's very slow RPM, so go slow on the feed rate. When I mill glass board I like a single flute, definitely carbide, with a 45 degree helix angle, up cut. Also you only need no more than 1/2 inch of flute bits so you can chuck it deep into the collet so you have minimum deflection. A two flute might probably be ok too, but I've never tried that, intuitively it just seems like a bad idea with 2 flutes. Definitely don't even try it with 3 or 4 flute bits. How long is the slot? That matters because of heat build up. Also don't attempt a climb cut, use conventional cut milling. So if your vise is holding it, mill it feeding it in from right to left. Go slow, if you see the bit glowing, stop, let it cool.
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I'll give it a try.
It's for one offs on stripboard.
You know when a component such as a PCB mounted socket has flat lugs & pins not at 2.54 centres?
Max 3mm long slot
In the past I have drilled holes oversize, attempted to drill holes mid way between existing holes (drill often wanders & falls into the hole) or used a small burr hand held in a dremel.
Incidentally, if milling a slot, one side is climb milling, the other side conventional so direction doesn't matter.
It's for one offs on stripboard.
You know when a component such as a PCB mounted socket has flat lugs & pins not at 2.54 centres?
Max 3mm long slot
In the past I have drilled holes oversize, attempted to drill holes mid way between existing holes (drill often wanders & falls into the hole) or used a small burr hand held in a dremel.
Incidentally, if milling a slot, one side is climb milling, the other side conventional so direction doesn't matter.