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

Political risk for an organisation, Identify, with examples, groups that ma...

Identify, with examples, groups that may represent a significant political risk for an organisation that is considering engaging in Foreign Direct Investment.  When companies a

Explain organization integrate the concept of compensation, Christian World...

Christian Worldview. How might an organization integrate the concept of compensation systems from an internal and external perspective, with an understanding of those same or simil

Explain the lead time for paper delivery, First printing has contracts with...

First printing has contracts with legal firms in San Francisco to copy their court documents. Daily demand is almost constant at 12,500 pages of documents. The lead time for paper

Explain use technology and information resources to research, Imagine that ...

Imagine that you are a senior manager for one of the following companies: • Apple • Burger King • Nike • General Mills Create a market entry strategy along with a st

Define ethical responsibilities and social responsibilities, Explain the di...

Explain the difference between ethical responsibilities and social responsibilities of a manager. Please in you own words.

State the major factors that affect location decisions?, state the major fa...

state the major factors that affect location decisions?

Give an example of what team performance, Provide an example of what team p...

Provide an example of what team performance readiness might look like at various readiness levels

Explain what is the evpi, State of nature decision ...

State of nature decision S1 S2 S3 D1 250 750 500 D2 300 -250

Explain limitations of budgets, Explain limitations of budgets. Limita...

Explain limitations of budgets. Limitations of Budgets : (i) Since budget is based on calculates approximately, that is, estimated sales, estimated business conditions and

Draw a p-chart based on the questionnaire results, You are the newly appoin...

You are the newly appointed assistant administrator at a local hospital, and your first project is to investigate the quality of the patient meals put out by the food-service depar

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