Grinding and Wire-Cut EDM are both machining methods for mold components, especially for stamping die components. Of course, 5-axis/3-axis CNC machining also can be used for making the tool and die components.
But compare with the quality of different machining methods, EDM (including wire EDM and sink EMD) is better than CNC machining; Grinding is better than EDM.
To be specific, in the precision tolerances, Grinding is doing better than EMD, and EMD is doing better than CNC machining.
In the Surface roughness and surface evenness, Grinding is also doing better than EMD, and EMD is also doing better than CNC machining in some places.
According to the speeds, CNC machining is the fast way for machining, EDM needs a longer time than CNC, and Grinding needs a longer time than EDM. But fast doesn’t mean the quality. In some respect, Slower Grinding is better than EDM and CNC.
Maybe Grinding is the best mechanical machining method for ultra-precision components in steel, HSS, or Carbide.
And there are various kinds of grinding, surface grinding, profile grinding, cylindrical grinding, centerless grinding, internal and external circular grinding, etc. We will not talk more about various grinding technologies here.
We just need to know that grinding is the basic and best machining method, and grinding parts quality are better than EDM and CNC machining(milling and turning).