Saw grind test for plated plastics

I am plating shop manager. Plating on plastics is my interest . I always tried to improve quality of plating. And it should be pass world all testing standards .I am facing problem to manage consistency in saw grind test . Although peel strength test pass (9.5 newton) Quick thermal cycle test also passed. Etching parameters also world class we are maintaining like 380 +-20 gm/lit chromic acid and sulfuric acid trivalant less then 15 gm/lit.

Saw grind test failure plating layer small chip out from base during cutting through 24 TPI hacksaw. Ductile test conducting monthly base which is also okay. Anyone suggest me what are the other reasons contributing for saw grind test failures ?