Process sigma Calculation
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 This topic has 5 replies, 4 voices, and was last updated 15 years, 11 months ago by qlychap.

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September 13, 2006 at 11:18 am #44590
qlychapParticipant@qlychap Include @qlychap in your post and this person will
be notified via email.I am willing to Calcullate the efficiency of the process. kindly help me out. Let me explain.
Each and every department in our organisation got a objective that the NC given to them should be closed within a months time. On a sample we started to calculate the process capability of the departments. below is the data on sample of a departmentNCR #
objective failed by
NCR0110406
27NCR0020406
28NCR0120406
12NCR0130406
12NCR0140406
12NCR0010406
28NCR0170506
67NCR0180506
67NCR0200506
67NCR0160506
10NCR0190506
10NCR0300606
31NCR0310606
31NCR0320606
31NCR0280606
79NCR0290606
79NCR0030406
6NCR0040406
6NCR0050406
6NCR0060406
6NCR0080406
6NCR0070406
6NCR0090406
6NCR0100406
7NCR0150506
4
On calculating the LSL is 1 ; USL is 30; Mean is 22 and SD is 29.23.
How can I quantify the department and how would I emplain to the departments. ? Kinldy help me out0September 13, 2006 at 4:40 pm #143180QlyChap,
First of all I would calculate your stats on the “Cycle Time” not the delta.
When I run your numbers I get:
mean of 51.5 days
median of 42
stdev of 29.2
Also looking from a perato concept 64% of your “NCs” are late. My next steps would be to do the same analysis by department so you can find the correct X. I would recommunicate the goal (30 days) and start posting the sample results by depatment. I had a project where department were assigned SOPs to review, our target was to have the document reviewed and any changes completed within 45 days, our historical average was 80 days. By making this a KIP for the facuility and posting the cycle times we are currently running at the 30 day mark. Each department had to evaluate there system of review and the changes in order to meet their target.0September 13, 2006 at 5:43 pm #143193Post the same data with the total turnaround time, and maybe we can help. As you have it stated, the data you have in the table is the number of days past 30 (objective failed by). Looking at the data like that would have only a 1 sided upper spec at 0 days past 30. So, first do that, then we can calculate the capability of meeting between 1 and 30 days. Based on you data listed, you had 9 out of 25 that beat the goal = 64% defective. Currently, not a capable process.
What is the result if the NC is not done on time ($, satisfaction, etc.)? Please indicate in your next post as well.
When I calculated the mean and standard deviaiton, I got the same thing you did, but wouldn’t use those numbers anyway. I would use the totoal cycle time it took to get the thing done.0September 13, 2006 at 5:55 pm #143194I would you assume that you just add a constant of 30 to the defect data in the file to get to the raw data.
0September 13, 2006 at 5:56 pm #143196Sorry – it’s been a long day.
0September 14, 2006 at 6:53 am #143234
qlychapParticipant@qlychap Include @qlychap in your post and this person will
be notified via email.The data given is not the time taken to close the NC. It is the time taken beyond 30 days to close the NC. Certain numbers would be in ve which means that the NC is closed before 30 days. There fore total cycle time would be +30 of the “objective failed by”
NC closure on time shows the commitment of the employee and management towards the Quality management system.0 
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