Regardless of the cutting method used there should never be any copper
near the cut line.
Mind that round hand operated punches typically have a pip in the
center to locate a center punch mark.
You may have to grind that off or maybe you can have a small hole
there and use it.
Some punches heavily deform the disc ( to make it smaller and fit
through the die easier), those may not be suitable.
I have seen small circular PCBs manufactured, and they were routed.
There are good reasons, routing is a standard manufacturing step the
commercial PCB supplier can do.
Also leaving the discs connected via breakout tabs means the whole
panel can be processed for machine assembly and testing.
ST
On Sun, May 11, 2014 at 8:32 AM, Peter Johansson
rockets4kids@... [Homebrew_PCBs] <
Homebrew_PCBs@yahoogroups.com>
wrote:
> On Sat, May 10, 2014 at 10:10 PM, Jean-Paul Louis louijp@...
> [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>
>> You’re going to wear your punch very fast as FR4 is loaded with glass which is very abrasive.
>> Unless you can have a very high resistance punch which would cost hundreds of dollars.
>> I used a punch press to cut boards in a previous job. The wear of the punches and dies were very costly.
>
> This is my concern as well. This is part of the reason I want to go
> with as thin a board as I can get away with. Do you recall how many
> cuts you were getting per punch/die set?
>
>> so we replaced the whole process by a router. But that was for 0.062” FR4.
>
> That is my other option. I am looking at something on the order of
> several hundred boards for my prototype run, and if I go into
> production beyond that I will probably have the boards professionally
> made. There are still a few unknowns, and I would prefer to work them
> out making the PCBs myself before setting up a job.
>
> Speaking of which, does anyone know a board house that is friendly
> towards lots of (cutting) routing?
>
>> You have also to make sure that there is no copper in the cut area.
>
> Yes, I had figured that the punch could damage any traces along the
> cut. That shouldn't be a problem.
>
> -p.
>
>
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