The technological process of mirror spark machine machining is a process from rough machining to finish machining. Firstly, a large amount of metal is removed by rough machining electrode with large discharge energy under the condition of ensuring certain machining quality (dimensional accuracy, shape accuracy, position accuracy and surface roughness), so as to shorten machining time and improve machining efficiency; Then change the finishing electrode and finish the finishing with less discharge energy. No matter rough machining or finish machining, multiple discharge conditions will be used, and the current will be from large to small, and the bottom will be polished by deep feed and the side will be polished by translation.

For each discharge condition, machining allowance should be reserved for the following conditions. Reasonable machining allowance is the key to ensure machining quality and efficiency. Large machining allowance can ensure the surface quality, but it will slow down the machining speed. Small machining allowance can achieve high efficiency, but the final machined mirror will have many pinholes or unevenness.