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

Systems approach - operations function, Systems Approach - Operations Funct...

Systems Approach - Operations Function In parallel with the development of management science, and also largely stemming from the wartime inter-disciplinary teams, an interest

Transaction Processing Systems, Discuss the organization structure and oper...

Discuss the organization structure and operation of a university. identify the different types of Transaction Processing System that can be defined for the university specify the d

Compute the service to club members as well as casual flyers, Evaluate the ...

Evaluate the service to club members and casual flyers by completing a table similar to table 3.1 (see page 70 Operations Management 6xth Edition Nigel Slack)

Briefly explain mcdonald''s value chain, Briefly describe McDonald's value ...

Briefly describe McDonald's value chain and discuss how information systems facilitate each component in the chain. How could information technology improve your next trip to McDon

Explain employee''s emails and online usage, From the video, take a positio...

From the video, take a position whether an organization has the right to monitor employee's emails and online usage

Make a fictional company and develop a memo to communicate, Create a fictio...

Create a fictional company and develop a memo to communicate the importance of a business continuity plan to the board of directors. The completed assignment should be at least 25

Explain what entry mode would you use, You are the Vice-President for Inter...

You are the Vice-President for International Development of a small U.S. pharmaceutical company (located in Emeryville, California) which specializes in the development of new medi

Describe confidence interval calculator, Practical Application Scenario ...

Practical Application Scenario To complete this scenario, use the Confidence Interval Calculator and the Area Gas Prices %u2013 Random Sample documents, provided in the Resource

The role of computers in POM, Obsolete technology can cost an organisation ...

Obsolete technology can cost an organisation its customers.Explain the role of computers in production and operations management

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