On 27 Jul 2014 17:01:43 -0700, you wrote:
>I was wondering how many of you folks use fillets in your PCB patterns where two traces, or any two edges for that matter, meet at 90 degrees.
I almost always bevel at 45 degrees. I rather wish that Eagle had a
"constrain to 45 degrees by moving both ends" behavior as an option.
>
>I was looking at some commercially produced patterns and they seem to frequently employ fillets. This is I presume to prevent cutting in of the pattern at 90 degree corners when the board is etched. For a pattern produced on a computer it's easy enough to add them in. Would it make any difference if one is using the toner transfer method?
>
I was told many years ago that traces had a tendency to break if they
were at 90 degrees (that was the expression they used). In theory, I
can imagine that etching through at the 90 degree junction may be a
problem. As such, I will avoid 90 degree joints (even T joints) and
bevel at 45 degrees.
I suspect that it was a result of etching (and etching ∗in∗ at the 90
degrees inside point), since they used photoetching (KPR) and had
production etching capability in house.
Therefore, the toner transfer method would not make a difference, one
way or another.
(or so says logic and my memory).
Harvey
>Thanks in advance for your comments.
>
>John