Hello everybody, I'm new here and I'm not native English speaker so I'm sorry for mistakes and describing some concepts instead of using professional vocabulary. I'm writing my engineering project and I've got a problem. I want to know how fast a process becames unstable while tools wears away to put new tools. I was trying to make measurement and every thee measurement (five samples in every measurement) count cp, cpk and cm and check how fast they became too low. I know it's a strage method but the company I cooperate didn't let me use any device measuring force at tools etc. So I was thinking that it would be a good idea. I'm not studying quality engineering but mechanical engineering so I don't know quality tools well. I wasn't albe to use laboratory as often as possible and I was doing up to three measurments a day (I don't know if it's an important piece of information so I'd better tell about this). I have no idea why but Cp are uncredibly high, there is no sign of wearing away of the tools (but they WERE really wearing out). I've read that to counting cp and cpk I may use 50, 100 and more groups. If I use very little number of groups, do the indexes increace? Is it possible that in my situation accetable level of Cp should be (for example) 3,6, not 1,67? What stranger, cpk increases instead of lower (the tools are kind of die). Can I still "save" my project or I made unforgivable mistake at the beginning?