What if Cpk index is more than 2 (Cpk > 2)

Dear Forum
Our company have been done the process validation of manufacturing tablet. The validation is conducted for 3 consecutive batch. In Process Control is conducted in compressing process of the tablet. the sampling of parameter tested (ex. assay, hardness, content uniformity) is done in 3 compressing speed, as follow :

  1. Minimum speed : 45,000 tabs/hour
  2. Maximum speed : 65,000 tabs / hour
  3. Normal speed : 50,000 tabs / hour

The checking was conducted every 2 minutes of time interval for both the minimum and maximum speeds, and every 30 minutes of time interval for the normal speed during compressing tablet.
Both the minimum and maximum speed was carried out for 20 minutes only.
The QC testing was conducted after the compressing process is completed with the sampling locating at the beginning, middle and end of the compressing process for each compression speed, are as follow :
1.The minimum and the maximum speeds
•The beginning of compressing tablet, from the initial, 2nd, 4th, and 6th minutes of time interval
•The middle of compressing tablet from the 8th, 10th, 12th and 14th minutes of time interval
•The end of compressing tablet from the 16th, 18th, and 20th minutes of time interval
2. The normal speed
•The beginniing of compressing tablet from the initial and 30th minutes of time interval
•The middle of compressing tablet from the 60th and 90th minutes of time interval
•The end of compressing tablet from the 120th and 150th ( if any ) minutes of time interval

Many of parameter tested (particullarly assay) have Cpk > 2 (2.19 - 14.79)
all the data input is in 100 or 60 datas

My question is, : Is Cpk more than 2 (2.19 - 14.79) are capable or allow in six sigma ?

Any input is appresiated

Regard,

annisa

The higher the CpK the better >2 means the process is highly capable. We’ve even had a CpK around 6. This just means you’re process specifications are really wide compared with the variation in your process.