Mechanical plating large components

This is regarding the mechanical Plating.I wanted to know why it cannot be used for large components.All the theory which I had gone all of them refer to small components and fasteners.Many experienced guys are there in this community so if any one can help this newbie it would be great help to me.
Thanks in advance.

It's simply a matter that mechanical plating works by tumbling the parts, Vaibhav. A tumbled part randomly falls onto a glass bead and if that glass bead happens to be sitting atop a particle of zinc, then the zinc particle gets smashed onto the part which is lying below it -- with the process repeated millions of times until all of the parts are properly coated.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

The mechanical plating and mechanical galvanizing processes are generally limited to parts under one pound in weight and under six inches in length. Above these two parameters, the energy imparted to the system is sufficient to crush the glass impact media, among other negative factors.

Mechanical plating and mechanical galvanizing offer two advantages over other plating processes: (1) no hydrogen embrittlement and (2) improved economics for heavier coatings (such as coatings over 0.0007"). If neither of these factors is present (parts under 32 Rockwell "C"; thicknesses under 0.0007") then other plating processes (e.g., especially zinc electroplating) have the advantage.

adv.