Can the word 'Proficiency' be used for non-living objects like Machinery,etc.?
Yes, it can be used. Take a look at the following example:
... is a reflection of the culture's ambivalent fascination with technology, which simultaneously fetishizes and fears the proficiency of machines and their ability to replace human effort.
However, it's better to use capability for objects.
By the experiments analysis, it can be known that the cutting capability of tools were determind by toughness of tools when the hardness of deposited materials