Do you mean for metalworking operations only, or all manufacturing?  Either way I have not yet run across a standard notation in my long mfg engineering career.  I am curious if one may be available.  Closest thing I can think of, is "Value stream analysis" notation which has some graphics for inventory and shipping operations, versus manufacturing; similar to process flow charts; but the 'value added' processes in those systems have always been given the same symbol regardless of the process type.

Thank you very much for your answers. I run across SysML and IDEF before, however they do not satisfy my needs :)

I guess there is a field one can work on.