A
aliasJohnQ
How do I set up a PPM with Total pcs shipped vs. Total Scrap for the month?
What is a good number and bad number?
Thank!!!!
What is a good number and bad number?
Thank!!!!
How do I set up a PPM with Total pcs shipped vs. Total Scrap for the month
I would think that you would want to know how many pieces are scrapped in proportion to how many are made, not how many are shipped. The standard formula is:
pieces scrapped/pieces made (or pieces shipped) * 1,000,000
If you make 1000 pieces and 10 of them get scrapped, the calculation is:
10/1000 = .01 * 1,000,000 = 10,000.
What constitutes an acceptable PPM level depends on what customers expect and what your process is capable of. In general, there's no good reason to use PPM unless your customers require it or you're actually making a million of something.
A
aliasJohnQ
Why isn't it a good idea to use ppm if your using less than a million parts of something???
What will the ppm number be if you have $950.00 of scrap but your total is: 780,000 pcs made. This is not all one part, but many.
What will the ppm number be if you have $950.00 of scrap but your total is: 780,000 pcs made. This is not all one part, but many.
How is saying your PPM is 10,000 better than just saying you have a 1% defect rate?
This is an apples/oranges comparison. In order for it to make sense, you need to use the same unit of measure for both quantities. In this case, you would need to know either the dollar value of the 780,000 pieces, or how many pieces are represented by the $950.
A
aliasJohnQ
Ok, I know how many are represented by $950.00. Then what?
Then you need to make sure you're not producing misleading results. For example, if there are 100 parts represented by the $950, it could be that one of them is worth $900 and the remainder are worth $.05 apiece. Nonetheless, if you know how many were produced and how many were scrapped, you can use the formula I gave earlier.
J
JRKH
The problem with using PPM is that it can be a number that is not "realistic" to many people.
If you are a company that routinely sets up and runs off many hundreds of thousands of identical parts, then such a number might make sense. You system is use to thinking in large terms.
However if yours is a company that routinely runs batches of a few dozen to a few hundred, then "Millions" is not a concept that is familiar and comfortable to most.
Say I run small batches of fairly complex parts and only ship 1000 per month. 2 of these are found defective and returned. Now I have a scrap rate of 1/500 but a PPM of 2000. Which of these numbers has more meaning to the people building the product?
If I routinely scrap 1/500 pieces it will take 1000 months, or 83 years to scrap 2000 parts.
Measures are only good if they are clear to those who must use them and understand them.
I agree with Jim Wynne that, unless PPM is required for a customer, there are more meaningful ways to measure Scrap rates and costs in ways that make sense to your orginization.
Peace
James
A
aliasJohnQ
What are the low cost ways to measure scrap vs. product out the door compared to PPM's?
How about scrap ($) as a percentage of sales?
M
MichelleH
I work for injection moulding company. We run aprox 30 moulding machines per shift. Internal Scrap figure for each machine is daily comunicated with production team (shift leader/process technician/operator)
For this comunication we use % of scraped parts from parts produced.
For the monthly reporting is our scrap divided into 2 categories:
1.IPPM (internal)
2.EPPM (external - customer compliants)
IPPM is counted with parts produced
EPPM is with parts shipped
For customer compliants we count % of sales to see the financial impact.
For this comunication we use % of scraped parts from parts produced.
For the monthly reporting is our scrap divided into 2 categories:
1.IPPM (internal)
2.EPPM (external - customer compliants)
IPPM is counted with parts produced
EPPM is with parts shipped
For customer compliants we count % of sales to see the financial impact.
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