Hard chrome for pure copper process

we have a pure copper part that made by cnc process.
we need 55HRC - 60HRC and 5-7 micron.
After the hard chrome process, we need to polish the part to get a mirror effect.

Dose someone knows, how many minute need to plate the part.

First, most chrome plate is harder than 60RC.
Second, you can not measure the hardness of a thin layer of chrome with a Rockwell type of tester, especially on a soft material like copper. You need a microhardness tester.
The length of plating time is going to depend on the solution temperature, the current applied and the anode to cathode spacing.
Your part will not plate evenly without using a conforming anode or robbers (thieves) and possibly shields. The center of your plate will have far less plate than the edges.
If you match the proper current for the tank temperature, you should get a very bright finish by starting with a good parent material finish.