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  3. Is Six Sigma the only certification available for business processes other than IT. Six-Sigma is more an efficiency measure, I understand. For non IT processes, how do you measure the maturity and capability of a process? IT industry has CMM certification with levels. What about functions like accounting, HR etc.? ISO is available but is more of a System Certification than Process. Answers and views invited. Thanks.
  4. Q 80. A component manufacturer (OEM supplier for a complex finished product) faces several unique challenges. One of them is as follows - The field failures reported by the client result in repairs and replacement costs to be borne by the component maker. Let us assume that the failures reported by end customer and client are genuine. Client wants improvements to be made so as to reduce reported component failures. Let us assume there are 20 possible reasons for failures. The component manufacturer wants to make improvements but has no mechanism to validate the root cause of field failures. This is due to two reasons. Failures show themselves only after usage in field over many months. Accelerated life testing is very costly and doing hypothesis tests for each cause is cost prohibitive. Improvements (based on guessed root causes) made today will show their success or failure in months or years to come. How should this situation be handled by the component manufacturer? Once This question is a part of Excellence Ambassador initiative and is open for 3 days. There is a reward of 5000 points for best answer in 3 days. All rewards are mentioned here - https://www.benchmarksixsigma.com/forum/excellence-ambassador-rewards/. The scoreboard is here - https://www.benchmarksixsigma.com/forum/business-excellence-scoreboard/ All questions so far can be seen here - https://www.benchmarksixsigma.com/forum/lean-six-sigma-business-excellence-questions/
  5. Yesterday
  6. What is Six Sigma, DMAIC Methodology?

    Great explanation and definition. If you could only have two tools in your six sigma toolbox which two tools would you use?
  7. Last week
  8. Control Limits

    Any matured process fall into one of the four states: 1. Ideal 2. threshold 3. brink of chaos 4. state of chaos an ideal process is one where the variations are within the control limits, increase in the variation means standard deviation is increasing and the the control limit X+- 3 sigma also increases at the same time. Therefore target should always be to stay within the control limits which is nothing but the voice of the process. We should always watch for the below in a control chart: a. if an observation is outside the control limits b. 9 points in a row above or below the center line c. 6 points in a row steadily increasing or decreasing Variation is present in output of every process. The degree of variation or distribution pattern of the output is an indicator of to what extent the process is matured. The six key process elements people, environment, material, machinery, method, and measurement impact the variation. If the variation is within a predictable range as mentioned at the starting which are nothing but the common causes of variation and over the period the process could still be brought down within the range after reducing the effect of common causes. on the contrary if we look for different ways to reduce the variation as defined by the customer we could never be able to reach an optimal solution because for a customer who is receiving an ordered food from zomato, +- 20 minutes could be a tolerance level where as for customer2 it could be +- 30 minutes. The question indicates variation level which sounds more like defined by the voice of the customer but by the voice of the process.
  9. Control Limits

    Based on the equations below, it is very clear that as the standard deviation increases, the UCL and LCL would shift widely(as the Variation is square of Std. deviation). So as the variation increases, the control limits also increase which would show that the process is in control despite the increase in variation. This can be addressed by making sure that the control limits are set based on the maximum allowable standard deviation and both the UCL & LCL to be made static and not variable based on the changing value of variation. UCL = Avg + 3*Sigma LCL = Avg - 3*Sigma where Avg = average of all the individual values Sigma = the standard deviation of the individual values.
  10. Hiring a Lean Six Sigma Black Belt Professional

    No. In my view, the basic quality to be seen while hiring a Business Excellence professional are, asking sensible questions, challenging the status quo & strong in Lean fundamentals.
  11. Hiring a Lean Six Sigma Black Belt Professional

    Togy Jose, 100% agree with you. Nowadays, many of the Business Excellence Professionals forget the basic tools like FMEA, QFD, etc.
  12. Control Limits

    Here is what i think; the answer lies in understanding the customer specification limits along with control limits. While we are monitoring the process using control chart, what is important is to keep a watch on the customer specifications. In a process where the variation is gradually increasing will in most occasions breach the customer specification, which fundamentally means we are not meeting customer requirement. So, maybe we should first get to meet the customer specification and then look at controlling the process…...
  13. Q 79. For Process Performance Assessment, one may use Capability / Performance Indices (Cp, Cpk, Pp, Ppk) or Sigma Level inter-changeably. Compare and contrast their utility and highlight why someone would prefer one over the other. This question is a part of Excellence Ambassador initiative and is open for 3 days. There is a reward of 5000 points for best answer in 3 days. All rewards are mentioned here - https://www.benchmarksixsigma.com/forum/excellence-ambassador-rewards/. The scoreboard is here - https://www.benchmarksixsigma.com/forum/business-excellence-scoreboard/ All questions so far can be seen here - https://www.benchmarksixsigma.com/forum/lean-six-sigma-business-excellence-questions/
  14. Long term performance of a process means Sigma Long Term and Short term performance of a process means Sigma short term. The question is why Sigma short term is calculated and treated differently than Sigma long term. Sigma short term of a process is usually given higher value than Sigma long term of the same process because, it is without any noise and reflects the current state of the process. Smaller deviation is seen in the process when measured in the short term, similar to students performing excellently in Unit tests and weekly class tests. The person studies a smaller portion and answers a smaller set of questions, similar to having a smaller set of population to test the performance of the process. In case of Long term performance of a process, the data points are more and hence more noise and more deviation. Greater deviation can be attributed to lot of factors and indicates measuring performance of a population rather than a sample. Hence Long term performance is measured differently. An anology would be the student performing well in the Annual exams. So simple answer is population and sample size determines it
  15. Long term vs Short Term

    Long Term & Short Term Process Capability: The Capability indices [ Cp, CpK ] & the Performance indices[Pp & PpK] can be considered as the Long Term & Short term on the Basis of Method used to calculate Sigma, an estimate of Process Standard Deviation. - Cp & CpK represent the Long term Process Capability, while Pp & Ppk represents the Short term Process Capability. - The AIAG suggests us that we can use PpK for a Production run of less than 30 days & CpK for everything there after can be used - Long Term Variability = Short Term Variability + 1.5 Sigma Shift. This Interpretation is based on the underlying assumption of Six Sigma, which indicated that the Process will drift or Shift +/- 1,5 Sigma in the Long term. When this shift is taken into account, 6 Sigma process performance equates to 3.4 ppm, otherwise 4.5 Sigma Process performance equates to 3.4 ppm. The Main reason why the Long term Performance is calculated & treated differently is that the Long term Process capability gives out the exact output of the current running Process. It also include the Common Causes that occur during the Process & gives us the result. During the Short term process, we cannot completely analyse the entire Process & Process Capability calculated during that period, may give us a hint only about the process. So Long term Process capability is preferred for complete understanding of the Process performance & calculate the Process capability
  16. I have little knowledge on the statistics and Math abilities. Chapter 3 of the precourse material is already in explaining these subjects. Are we looking for intense course material in statestics and Math when we attend the 4 day course? Will teh Exam be based on solving problems with math abilities? Can we have a sample precourse quiz to take and have a feel of the course we are looking forward to attend? Any sample questions on the Exams?
  17. Long term vs Short Term

    Long term performance is to be treated differently compared to short term performance as there is a scope of random variations that could be introduced in the process because of several changes which could be but not limited to new employees in the process, change in measuring standards and/or any abnormalities that could have run into the process. As the scope for this to happen in measuring short term performance is less, and as there would be more number of subsets in long term(of short term), the performance could most probably come down in long run. This is even supported with the calculations of Short and long term sigma where usually the long term sigma is a difference of short term sigma and 1.5(one point five sigma) to attain long term sigma value.
  18. Before proceeding lets define what’s long term and short term. For easy understanding say 1 year and above is considered as long term and anything below 1 year is short term. The variations or challenges might not vary drastically in a Short term process. Where as a long term process would have higher spikes. Short terms cannot have a compounded effect, but long term has. Considering the investment, long terms always fetches good returns compared to short duration. Employees who work in the same company for longer period are considered as seniors irrespective of their performance where as a new employee will be treated differently (again irrespective of the performance). Short terms may seem attractive, but long term is taken for granted (in terms of process).
  19. Long term vs Short Term

    The long term performance or also known as “Long Term Capability” for a process, itself implies that it has to be taken for a reasonable period of time. At any given point of time, if we measure the process capability for a process, it will always be the “Short Term capability”. The short term denotes to process potential, when operated under a set of variations that are always expected to be inherent in the process at any point of time. Statistically these are variations that may be typically depicted by the spread of an associated normal distribution on both sides of the mean value. It is particularly useful to quickly understand the effectiveness of a change that is expected to reduce the variation, i.e. improve the process capability. If the short term capability itself does not meet the expected requirements, there wouldn’t be a need to run a long term capability. Knowing that during the long term a process will get subjected to additional variations the could impact in the shifting of the mean value, it is important that the short term capability has to be adequately good enough to enable the process to accommodate additional variations in the long term, so that the long term capability will still meet the expected requirements. Considering the practical challenges in terms of the time and effort in obtaining the long term process capability, it has been agreed that during long term, one may expect a shift of the mean value by 1.5σ on either side of the mean will be an acceptable indication of the long term capability. Thus in order to attain a long term process capability of 4.5σ, we need to ensure a short term capability of 6σ.
  20. Control Limits

    For statistical Control charts, the control limits are formed by its own historical data. To answer the above question, let’s quickly recap the process of forming the control limits. Typically the inputs based on past 30 or more data points are taken and the control limits are worked out using the formula depending upon the nature of the data and the appropriate control chart applied. I am skipping the elaboration of the control chart construction in this discussion. (i) Once the control limits are derived as above, this becomes a baseline situation, against which the readings are plotted subsequently. Since we keep the limits fixed based on the baseline inputs, if the variation increases, the points will start falling outside the control limits, or would start representing the runs that indicate that the process is no longer in control with respect to the baseline limits. (ii) Another scenario is if we do not fix the baseline limits, but the UCL and LCL keep revising themselves as when the data points are added into the control chart. In this case, if the variation increases, the control limits will keep widening and might give an illusion that the process continues to be in control. As a matter of fact, the process can still be termed as “within statistical control” even with an increased variation, so long as the points are contained within those widened limits. (iii) Hence, to keep track of the changes in variation levels and at the same time to watch whether the process is within statistical control, “stages” can be defined for periods of the control chart run, and the control limits for each stage can be worked out. This will help us to graphically see any changes on the variations (distance between the control limits) and the extent of statistical control within each stage. Such an option is available in Minitab.
  21. Q 78. DPMO (Defects Per Million Opportunities) is used as an alternative to PPM (Parts Per Million Defective). For customers, defective items or Non- Conforming outcomes is a prime concern and they have penalty clauses based on PPM. Companies sometimes prefer to use DPMO instead of PPM as a measure of process performance. Explain specific situations where DPMO is a better measure as compared to PPM and vice versa. This question is a part of Excellence Ambassador initiative and is open for 3 days. There is a reward of 5000 points for best answer in 3 days. All rewards are mentioned here - https://www.benchmarksixsigma.com/forum/excellence-ambassador-rewards/. The scoreboard is here - https://www.benchmarksixsigma.com/forum/business-excellence-scoreboard/ All questions so far can be seen here - https://www.benchmarksixsigma.com/forum/lean-six-sigma-business-excellence-questions/
  22. Control Limits

    Control limits indicates voice of process. They are based on the past performance. On the other hand specification limits are the voice of customer. If variation increases and control limits shifts gradually and becoming wider but seems to be process is in control throughout entire period of process. We can say that it is possible to a process to be incapable of meeting a specification while remaining in statistical control. Predictably, We are making a product out of spec.
  23. Q 77. If variation gradually increases in a process output, the control limits (in the control chart) will shift gradually and become wider. The process in such a case may seem to be in control through the entire period. How is such a phenomenon supposed to be addressed? This question is a part of Excellence Ambassador initiative and is open for 3 days. There is a reward of 5000 points for best answer in 3 days. All rewards are mentioned here - https://www.benchmarksixsigma.com/forum/excellence-ambassador-rewards/. The scoreboard is here - https://www.benchmarksixsigma.com/forum/business-excellence-scoreboard/ All questions so far can be seen here - https://www.benchmarksixsigma.com/forum/lean-six-sigma-business-excellence-questions/
  24. Earlier
  25. Long term vs Short Term

    There is a shift of 1.5 sigma between long term and short term performance of a process. In other words a 6 sigma short term process would be a 4.5 sigma long term process. This is because the data considered for a short term performance calculation just has common causes of variation, is collected from from narrow inference spaces and restricted sampling is done like collection from one lot, batch, etc. However, when data is considered for calculation of a long term process performance calculation, it is collected from different time frames, broader inference spaces and sampling is done from multiple batches, lots, etc. As such this data along with common causes of variation also has special or assignable causes of variation. Hence a high sigma level for a process in short term lowers by roughly 1.5 if the long term performance of the same process is considered.
  26. Long term vs Short Term

    The process capability and hence the sigma level of an improved process will be at a greater level, as soon the improvement is done. Because every process will have a natural degradation, the process capability and hence the sigma level of that process will lower down, over period of a time. Motorola figured this out quite early and made a shift allowance of 1.5 sigma . Long Term variation = Short Term variation -1.5 Sigma. Very simple example for a process degradation : If a road is being laid out on National Highways, for one/two month(s), there may not be a soft spot or potholes or damaged spots. But by 4-6 months, the road may be severely damaged or even inaccessible. This is due to multiple causes such as Env.conditions , heavy traffic, more heavy vehicles operating Another example is Software Code deployed in production. First one or two months or during the warranty period (Short-term) there would not be much issues or minimal issues.But post that (long term), the issues could creep more as we may not have SMEs available, new team might work on the supporting the application,...
  27. Measurement System Analysis

    Thanks much VK.
  28. Measurement System Analysis

    Hi Giritharaprasad, You are right in saying that Gage R&R is not needed. You do need to carry out logical validation though. Basically you need to verify that the system generated data - Uses a validated method of data capture (error free and timely) The data being recorded matches the definition of the CTQ that you have selected in your project.
  29. Measurement System Analysis

    Hello Team, I am executing a GB project on Productivity improvement. All the required data are generated by the application thorough query to mine from application itself. in this case, do we need to do a Gage R&R Study? if Yes, what results should be considered as Operator and which result should be considered as Part to Part?
  30. Q 76. Why is it that long term performance is calculated and treated differently from short term performance of a process? The answer with the simplest and accurate description will be preferred. This question is a part of Excellence Ambassador initiative and is open for 3 days. There is a reward of 5000 points for best answer in 3 days. All rewards are mentioned here - https://www.benchmarksixsigma.com/forum/excellence-ambassador-rewards/. The scoreboard is here - https://www.benchmarksixsigma.com/forum/business-excellence-scoreboard/ All questions so far can be seen here - https://www.benchmarksixsigma.com/forum/lean-six-sigma-business-excellence-questions/
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