Poor cut quality

[DMW]

Hi,

I recently picked up a Bungard CCD/2 milling machine, so I am hoping for some professional quality isolation milling.

It came with some unbranded (Just in a unmarked plastic container) 0.2mm 30-degree V-bits, these bits are a delight and cut beautifully at 750mm/min, 60K RPM, they cut a little wide, the total width ends up being about 0.45mm (about double for some reason?)

Now I really want to cut at ~0.2mm width. So I have bought some 0.1mm 30-degree and 10-degree bits, so far I have bought 3 different inexpensive sets of bits. Each time the cut is really really bad, they tend to cut at around ~0.3mm with a really unacceptable finish. Under the microscope the bits dont look any different (to me) from the 0.2mm bits I mentioned above.
I have tried cutting at different speeds, RPM and cut-depth (120mm/min, 450mm/min and 600mm/min, and spindle speeds 30K (minimum) and 60K (maximum) without much improvement.

I have just tried some 0.2mm Chinese 30-degree bits I bought, so in theory the same as the unbranded ones which came with the machine, but again the cut was really bad, so I am guessing its down to the quality of my bits? (Though some had some good reviews on Amazon).

I once read about using cutting oil, I have also just tried to place a small amount of machine oil on the copper area to be milled with no effect.


Can anyone please recommend a supplier of good quality engraving bits for PCB isolation routing (10 to 30-degree) I can get in the UK?

I have attached some pictures of what my cuts have looked like, as you can see all the Chinese stuff is just very wrong!

Many thanks in advance,
Dom