[Amps] mounting (UHF) RF powermodules

[Steve Thompson]

>>Expanding on those, any heatsink you buy will not 
>> be flat enough without machining, ideally with a large diameter 
>> 'fly' cutter. You are also looking for a good surface finish with 
>> machining ridges barely detectable with a fingernail. As well as 
>> flat (50um or .001" over the module area) clean is important.<
> 
> Not sure that I would agree about a fly cutter. Better than nothing, but I 
> would prefer 
> a horizontal milling cutter. Alternatively, a face-and-end milling cutter. 
> A large slot drill 
> might give a good enough finish.
> 
> Another good way would be to use a shaping machine.

The choice probably varies with the machinery available. Up to 6" 
wide I get things skimmed on a single pass and they give me a low 
roughness finish. With end cutters or slot drills the finish is 
usually excellent but there can be a tendency for tiny 
steps/ridges between passes - I've learnt to specify that any 
mounting area must be cut in a single pass.

Steve