Defect Vs Defective for DPMO Calculation
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Perera.
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October 31, 2008 at 10:39 am #51234
Hi,
I have started using six sigma concepts and i have one basic question on the DPMO calculation.
If we are taking the defect as base for DPMO. How can we define that defect and how it is different from defective.
Can any one help me out0October 31, 2008 at 11:41 am #177275How I take this and I’m not saying I’m right is that if your final product has 10 ways of being wrong and your measuring each of these then your measuring defect, (10 opps) but if you say well that it’s either good or bad then your measuring defectivies (1 opp).
In my opinion measuring defectivies measures what the customer feels so is the better of the two. Defects can easily be used to make your system look a lot better than it is by adding in a couple of opps which never fail.0October 31, 2008 at 11:52 am #177277Rejections in Nos
Base Line SigmaStage 1 Loss
Stage 2 Loss
Customer Returns
Total
Production Qty
Loss Percentage
DPMO
Short Term
Long TermDPO
Case 1
Apr’08
9383
13523
0
22906
243116
9.42
94218
2.8
1.3Case 2
Apr’08
9383
13523
0
22906
243116
9.42
7851.53
3.9
2.4
In case 1 i have taken PPM
In case 2 i have considered 12 types of difects can occur in any of this defect products.0October 31, 2008 at 3:37 pm #177284Suresh,
A unit of product may have many types of defects. Any one non-confirmity is a “defect” and a unit with a defect or many defects is called a “defective” unit. This is the fundamental difference between defect and defective. For example, one product has only one defect, that product is a defective unit-more than one defect in one product is also called a defective unit. For DPMO calculation you need to consider no. of defects in each unit.
Best Regards,
Pramod0October 31, 2008 at 4:00 pm #177286DPMO = DPU x 1,000,000
0October 31, 2008 at 11:22 pm #177301
Mike CarnellParticipant@Mike-CarnellInclude @Mike-Carnell in your post and this person will
be notified via email.Suresh,You haven’t gotten a correct answer yet.Good luck
0November 1, 2008 at 9:08 am #177313We are producing components and having 4 stage process the product will be rejected due to 12 types of defects ( all type of defects will not be present in one rejeced sample)
Total Productin Qty – 4,18,534
Total Rejected Qty – 22210
Total types of defects considered 12
DPO = {22210/(418534×12)} = 0.44
DPMO = DPO x 1000000 = 0.44 x 1000000 = 440000
Is it Ok
0November 2, 2008 at 12:26 am #177322Suresh,
What is your Y?
Pramod0November 2, 2008 at 5:04 am #177323
Mike CarnellParticipant@Mike-CarnellInclude @Mike-Carnell in your post and this person will
be notified via email.Suresh,You need to use your head and think about the advice you are getting. If you want to use DPMO then you need to start with the number of opportunities you have. It has nothing to do with the possibilies to makes types of errors. It is the opportunities to do something correctly. The simplest calculation and is somewhat conservative is parts plus connections.Going from Number of opportunities it should be pretty straightforward to calculate defects per opportunity (DPO) and if you want DPMO you multiply by……It doesn’t have anything to do with DPU or what your Y is.You need to think about what the words mean and stop being a sucker for such crappy advice. You should be able to figure this out for yourself.Good luck.
0November 3, 2008 at 5:34 am #177338Use a “c” chart for the number defective.
Use a “u” chart for the number of defects.
There’s volumes on the net explaining these two charts.
… ooops … but neither of these have anything to do with “six sigma” defects and six sigma’s “sigma” can’t be used either !!!!
Anyone who believes in “3.4 defects” needs his head examined.
0November 3, 2008 at 6:23 am #177339
Thilanka MarasingheMember@Thilanka-MarasingheInclude @Thilanka-Marasinghe in your post and this person will
be notified via email.Hi,
Can anybody propose us a good theme/slogan for our company six sigma community
TM0November 3, 2008 at 9:06 am #177340Stan,
if your actual process is free of any shifts and is perfectly normal it produces 0.002 defects0November 3, 2008 at 10:47 am #177342Sick Sigma
Opporunity count inflaters
Deming Slogan Committee
Just a few options
0November 3, 2008 at 1:01 pm #177346
Sridhar SukumarMember@Sridhar-SukumarInclude @Sridhar-Sukumar in your post and this person will
be notified via email.Hi Suresh,
Assume you are a manufacturer of Gear Box with 10 gears in it. If you supply this gear box to a car or a stationary machine you treat failure of individual gears seperately so defects(DPMO) is what you see. If you supply this gear box to an Aeroplane, the criticality of each gear is high so any failure would be equal to failure of the gear box, the entire unit. Here it is defective(DPU).
Regards
0November 3, 2008 at 4:05 pm #177352
Jonathon AndellParticipant@Jonathon-AndellInclude @Jonathon-Andell in your post and this person will
be notified via email.I’ve always been fond of “Old Hat, New Feathers.”
0November 3, 2008 at 5:12 pm #177359Suresh,
Send me your email address. I will send you an Excel file which shows the difference between a DPMO calculation and a defective calculation (Yield).
Cyrus0November 7, 2008 at 5:48 am #177473Dear Cyrus,
Here is my E mail ID :
[email protected]
[email protected]
Suresh0 -
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