How to manage with customer % failed product

[QAMTY]

Hi all,do you have an idea of how to explain the customer that the % of bad product is 4 %.
My case is we manufacture steel bolts,but we inspect only part of the product,not all bolts are inspected.how is this managed? ,will be enough to include it in the quotation? E.g. 20000 steel bolts 1/2 inch diameter,and 5% maximum reject of bolts?
Please share your experience.
I have ISO 9001 2008, Thanks

 

[Mike S.]

How do you determine that 4% are bad?

Is that typical for your industry -- seems like a very high defect rate.

 

[QAMTY]

Thanks Mike
It was an example,really Its 1.5%.
Thanks

 

[Mike S.]

Okay, how do you determine that 1.5% are bad?

Is that typical for your industry?

 

[hogheavenfarm]

I assume you are sampling to a sampling plan, so you should be able to get a good indication of the actual percentage. You then need to communicate this to your customer in the form of a 'tolerance'. Milled steel is supplied to similar 'tolerances' for flatness, thickness, etc. This is really a way of saying that one can expect wide ranges in the specified product which will be say, 0.060" thick nominal, but may vary by 10%.
If your customer is also sampling, then you can supply a limit % number which will cover this amount, but remember, your customer wants to see zero defects, as each defect costs both money and time for them, and for you. A better approach would be to reduce defects through a targeted program. There will always be a certain number of defectives, but reducing the number will pay off better than increasing a 'tolerance'.