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

Supply chain, #question. 1. how does a formal procurement policy affect cus...

#question. 1. how does a formal procurement policy affect customer service

Describe different steps needed for proper decision making, Question: O...

Question: Oceania Hospitals has recorded demand for heart transplant surgery over the past few years. The data is given in the following table: a) You have been hired

Compute the estimated sample size needed, Practical Application Scenario 2 ...

Practical Application Scenario 2 To complete this scenario, use the Sample Size Estimator file provided in the Resources. The third shift at Microsoft's Windows' security uni

Explain how can the hrm professional be prepared to deal, How can the HRM p...

How can the HRM professional be prepared to deal with the variations in HR practices in the global environment

Describe why is it vital to pay more attention to firms roe, Explain why is...

Explain why is it important to pay more attention to the firm's ROE if you are the firm's shareholder (investor) and explain how to use the DuPont equation to see how the ROE can b

Describe what is the reorder point, The injection moulding department of a ...

The injection moulding department of a company that operates 24x7 uses an average of 20 gallons of special lubricant per day. It takes two weeks for an order of lubricant to be del

Major challenges in relation to organizational behavior, Question 1: (a...

Question 1: (a) What does Organisational Behaviour mean to you? Use your own words to explain the concept. (b) Describe carefully the major challenges organizations are fa

Disadvantages, What are the disadvantages of operation management?

What are the disadvantages of operation management?

Explain ethical principles in marketing situations, Applying sound ethical ...

Applying sound ethical principles in marketing situations: a.is a losing battle. b.must be a continuous process. c.requires a major competitive fight. d.is impossible for most comp

Scheduling - production control, Scheduling Meaning and Definition ...

Scheduling Meaning and Definition Scheduling is the next technique of production control. In production control scheduling  means  the  arrangement of different operatio

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