I'm in the process of finding the perfect settings and tools for PCB milling.

I’m in the process of finding the perfect settings and tools for PCB milling.
I got a chinese silent spindle with 12k RPM and a heavily modified Shapeoko 1 (basically a Shapeoko 2).
In the past i used 10 deg v-bits but experienced heavy problems with broken bits (0.1 mm depth, 80 mm/min).
I have many PCBs with TQFPs (0.5mm distance between pins) or even SO-16.
The minimal isolation witdh should be something like 0.2 mm.
So can anybody give me a hint where to find the ultimate end mill with a diameter of 0.2 mm or 0.3 mm.
I’ve seen people here using 0.3 mm end mills. What speed at 12k RPM and depth can i achieve using those? I am just afraid of buying a 25 $ end mill and breaking it on the first time using it.

I started out with a shapeoko and gave up on timing belts as I could never get clean accurate traces so that’s possibly your bigger variable than the end mill. I have had success with Kyocera tools 0.3 and 0.2. Check out my micro milling pcb video on YouTube.

@ameen.nihad ​ was showing here nicely milled 2-sided PCB using 0.3mm end-mill and a CNC 3040 few days ago. But I don’t know his parameters (feed rate, rpm and depth).

Please try this endmill with maximum spindle speed: https://www.stepcraft-systems.com/zubehoer/einsatzwerkzeuge/vollhartmetall-vhm-gravur-fraeser-mit-spiralnut-1-schneide

@sszafran ​ I use the default 80mm/min feed rate, not sure about rpm, I have manual speed spindle with max 12000rpm, but I don’t run it at full speed, probably around 8000 rpm.

@jlauer : The CNC 3040 with ballscrews looks totaly cool, but i put a lot of money into my Shapeoko. So switching CNC is not an option :confused:
@ameen.nihad
: What end mill did you use? Can you give me a link?
@Frank_Herrmann : Thanks! I will definitly look into it!

I look at my Shapeoko2 moving and the motion seems horrible. I think a lot of that problem is the arduino with GRBL board. The movement of my SeeMeCNC Rostock Max v1 is much smoother with a different board but a belt wrapped over a pulley the same size as the one on the Shapeoko2. I am not sure if the Rostock Max is accurate in positioning to 0.2mm or not, but it is certainly better than the Shapeoko2. There should be many options for controller board replacements.

@Edmar https://www.aliexpress.com/item/3-175-0-3MM-Solid-Carbide-PCB-Milling-Bits-Cutter-Tool-Printed-Circuit-Board-Cutter-PCB/32296631557.html?spm=2114.13010208.99999999.6.OdLcKR

I had the same experiences with shapeoko imho an grbl arduino with cheap stepper drivers. I guess this drivers works very innacurate. I saw a video that try to proved this. Can’t find it.

Also beware of rotary tool shafts getting bent or the bits not being clamped squarely by the chuck/collette/whatever.

I read a couple of weeks ago that the high spindle speed caused heat problems for small carbide bits and the recommendation was low spindle speed and a higher feed rate. This seemed wrong to me when I read it and I haven’t followed up on the science…

I’m using maximum available spindle speed, which in my case is 12krpm, 50-60mm/sec feed rate and usually no more than 0.1mm depth. I never saw differences in milling leading me to a cooling problem conclusion, but on the other hand I haven’t run extremely long jobs. Possibly compressed air cooling might help here.

I always thought that high rpm (20-30k on bigger CNC machines) is a key for engraving.

That was my logic too. I suspect the article I was reading may have muddled feed rate and spindle speed.