PCB Engraving / Cutting

[jrob3rts]

Hi All,
Wonder if I can pull some of that knowledge from you. I have myself a Marchant Dice A3 machine and one of my projects I shall be undertaking is some PCB work. I have previously been using the UV and Acid approach but it's lengthy and not clean.

I keep seeing some PCB bits on eBay which are incredibly cheap and look like Vs' on the end of shank.
Is shank the right name?
So, are they any good for light work?
Am I better off using an end mill or ball nose?
Any other suggestions?

I'm not after anything for really small work however if I can go smaller then I can rethink and improve the design if I see fit.

Check out my examples below which show the kind of work I am thinking of doing. This is my NanoLight V3 Project for illuminating Reef Tanks.

Thanks for your time.

James

Side A
https://lh5.googleusercontent.com/_gp555ubnpis/THbA7Kf6l-I/AAAAAAAAJog/LpKshh4WFEQ/s720/DSC01017.JPG

Side B
https://lh5.googleusercontent.com/_gp555ubnpis/THbA8T9hCII/AAAAAAAAJoo/Y6qDLlAgtY8/s720/DSC01018.JPG

End Product
https://lh3.googleusercontent.com/_gp555ubnpis/TIwHsbERaZI/AAAAAAAAJp4/0XMjhfaUiuQ/s720/DSC01227.JPG

End Product under test
https://lh4.googleusercontent.com/_gp555ubnpis/TIwHoR--9YI/AAAAAAAAJps/oivrrVs-QoU/s720/DSC01224.JPG

[jrob3rts]

Bump. Any thoughts here peeps?

[wiatroda]

Am I better off using an end mill or ball nose?
Any other suggestions?

Nice tank, It reminds me my adventure with cichlids few years ago.

To produce PCB I use carbide CNC PCB engraving bits. I bought them from http://www.virtualvillage.co.uk/3-x-1-8-carbide-cnc-pcb-engraving-bits-tools-machine-007807-075.html?utm_source=googlebase&utm_medium=shcomp (http://www.virtualvillage.co.uk/3-x-1-8-carbide-cnc-pcb-engraving-bits-tools-machine-007807-075.html?utm_source=googlebase&utm_medium=shcomp)- best price I found so far.I can't tell you how long they will last. Mine still works fine.

My first ever PCB cut with those bits:
http://www.mycncuk.com/forums/showthread.php/3338-My-first-ever-CNC-cut-PCB (http://www.mycncuk.com/forums/showthread.php/3338-My-first-ever-CNC-cut-PCB)
How many PCBs are you going to produce??
Hope that helps

[Jonathan]

Shank is the right name.

The best way to do it is to use a sufficiently small diameter endmill. The good thing about and endmill is the depth of cut does not matter, unlike a V-cutter which requires the PCB to be flat to maintain a constant isolation gap. Also and endmill may well have 2 or more flutes, so you can cut faster.

I've used V-cutters in the past - use about 60mm/min feedrate per 1000rpm spindle speed. So for instance a 24000rpm spindle gets 1440mm/min. If you go faster you might leave burrs.

The PCB you're making looks extremely simple - the isolation gap is large. That's good since you can use a relatively large endmill and thus feed it faster.

I posted about it here:

http://www.mycncuk.com/forums/showthread.php/3338-My-first-ever-CNC-cut-PCB?p=21637&viewfull=1#post21637

I use a 2mm slotdrill to cut out the PCBs:

http://www.youtube.com/watch?v=vDNScafwTYw

(The spindle speed on the mill is only 2150rpm,hence the slow feedrates)

[jrob3rts]

Both great answers and very welcomed. The wide tracks were set because it's easier so can play with those.
Love the cut depth in the pics too, makes it stand out more :)
Right, am off to check out my cutters and see if I need to buy some more.
Thanks again.
James

[jrob3rts]

Forgot to mention. How many PCBs? No idea, not planning on many but this is all about fun and learning so will have to see.

[wiatroda]

This is all about fun and learning.
1000000000000% agree :)