4 Replies Latest reply: Aug 14, 2010 2:14 AM by Steven Kastell

# what is Parts Per Million and how to find it

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Hi to all ,

Please can any body tell me , what is Parts Per Million and How to find Parts Per Million .

As i have to find Internal , external and customer Parts Per Million .

Can any body send me example or website link , which can help me .

I shall b thank full to you for this.

Regards

Pavneet Rana

• ###### Re: what is Parts Per Million and how to find it
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• ###### Re: what is Parts Per Million and how to find it
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1mg/kg = 1 ppm

• ###### Re: what is Parts Per Million and how to find it
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Dear Pavneet,

Please can any body tell me , what is Parts Per Million and How to find Parts Per Million .

As i have to find Internal , external and customer Parts Per Million .

PPM is the concept or process to calculate  the defects / rejects  per million.

Following is the simple example to explain PPM :

Previously people use to calculate rejections / defects in %, many companies use to say that they work at 1% rejection level. Workmen use to feel satisfied  that the rejection is too low  (1%).

This PPM concept shows same results at wider perspective  and creates good opportunity for reducing the rejects further :

1% Rejects  means you manufactured 100 and 1 is rejected. PPM express this in other way as follows:

Million means 10 Lacs, so in PPM language  same can be seen as 10000 rejects from 10 Lacks produced ,this gives the feeling that there is huge rejects and even if you reduce it by 50 % 5000 rejects  can be  avoided.

Then comes concept of six sigma, here your rejects / failure level is only 3.4 PPM i.e. you generate only 3.4 rejects per 10 Lacks produced. Hence bringing rejects from 10000 nos (1%) to 3.4 nos is very  big achievement and profit to any management. Few companies in India has achieved 3.4 PPM.

Now coming to your question, how to calculate PPM:

If you sale 5000 parts and  100 parts rejected by customers in that month then : Rejection is 2%

PPM =  (% rejects)x 10000  = 2 x 10000 = 20000 PPM  OR other way is

PPM = (No.rejects) / ( total sale) x 1000000(10 Lacks) = 100/5000*10 Lacks = 20000 PPM

so you are working at 20000 PPM level for customers, which is very bad. and should try to reduce to three digit level.

Best Regards

Shekhar

Edited by: Shekhar Mokashi on Apr 22, 2010 9:51 AM

• ###### Re: what is Parts Per Million and how to find it
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Parts per Million is how the contents of gas is measured.  Levels in exhaust gases of a car exhaust are measured in parts per million.

The reject rate is DEFECTS per million.