Process capability index - asymmetrical positioning, Operation Management

Assignment Help:

Process Capability Index - Asymmetrical Positioning of the Process

As stated earlier, the Cp index assumes that the process mean is centred within the tolerance band, but, in practice, this is often an unreasonable assumption. For this reason, alternative indices have been devised which take account of asymmetrical positioning of the process mean relative to mid-tolerance. Consider the process output represented in this next figure, for which the LSL is 10, the USL is 20, the process mean (µ) is 18 and the standard deviation (σ) is 1.166. For this process the Cp index value is 1.43 [i.e. (20 - 10)/ (6 × 1.166)], which might suggest that the output has a very low level of non-conformance. However, as can be seen from the figure, a significant proportion of the output actually lies beyond the upper specification limit. The Cpk index takes account of the asymmetry by relating the spread of one side of the output distribution (3σ) to the difference between the process mean (µ) and the nearest specification limit. Two calculations are performed, and the lowest value (worst case) is taken as the index value.

1148_Process Capability Index – Asymmetrical Positioning of the Process.png

In the example in the figure above, the Cpk index is 0.57 [ie (20 - 18)/(3 × 1.166)], indicating that the process, as currently set, is not capable of producing to the design specification. The following figure shows the significance of different Cpk values.

1302_Process Capability Index – Asymmetrical Positioning of the Process 1.png


Related Discussions:- Process capability index - asymmetrical positioning

Explain why should be performed before signing a contract, What due diligen...

What due diligence should be performed before signing a contract?

Evaluate optimal order quantity, (a) Supply chain management is the integr...

(a) Supply chain management is the integration of the activities that procure materials and services, transform them into intermediate goods and the final product, and deliver the

OPERATTION MANAGEMENT, DISCUSS THE ADVISABILITY OF USING MODULAR ASSEMBLIES...

DISCUSS THE ADVISABILITY OF USING MODULAR ASSEMBLIES IN MANFACTURING

Explain leadership training and development, Leadership training and develo...

Leadership training and development throughout all levels of the organization. From your experience discuss the importance this component and why? Include examples

Explain the expected rate of return, Debt: Jones Industries borrows $6...

Debt: Jones Industries borrows $600,000 for 10 years with an annual payment of $100,000. What is the expected interest rate (cost of debt)? Internal common stock:

Explain regression equation relating expected travel, Accountants at the fi...

Accountants at the firm Walker and Walker believed that several traveling executives submit unusually high travel vouchers when they return from business trips. The accountants too

Explain the organizational structure that results, Describe the organizatio...

Describe the organizational structure that results from each of the different bases of departmentalization?

Describe senior management prospective, Develop an 8 to 10 page marketing p...

Develop an 8 to 10 page marketing plan for a sports enterprise (e.g. professional, school or community program). You will take the position of the manager and develop a plan that y

Explain quality management program, Use your critical thinking skills and d...

Use your critical thinking skills and discuss what you can deduce from this data. Please think about both behaviours and processes and linkage to the quality management program.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd