On PPAP reference manual section 3.1 does not state a specific period of time. You're advice will be greatly appreciated.
I would be surprised if your customer's haven't made that advanced notification expectation clear to your company at some point, at least with your sales and marketing folk... You may want to get in touch with them to see if any have already contacted your customers?
Not to panic you or anything, but from my experience the timing can be based on the industry you are supplying:
- with our automotive customers, I think they would be very upset if they didn't get at least a 4 to 6-month advance notice of any major changes which may affect the materials they purchase.
- with our cosmetic customers, they like to have at least a two month advance notification.
- for our industrial customers, 2 weeks advance notification is OK, but at least one-month advance notification is preferred.
Please also note that sometimes a change is necessary on very short notice... These should be the exception, not the rule. As soon as a change has been identified, someone should be asking the questions = does it / could it affect our product? or our ability to supply our customers? and do we need to notify our customers? and if so, when?
By way of example, for my site, we deal with a corporate sales and marketing force. In the past, our site was not made aware of what kinds of discussions the sales and marketing folk were having with our customers. Now (for the past several years), under our current systems, and under our current management, sales and marketing people interact with all of our manufacturing locations on a daily basis and we have a good understanding of our customer requirements, including how far in advance we should be notifying the customers of a change. Actually, we notify our sales and marketing folk as far in advance as we are able, and it is our sales and marketing team's job to notify the customers as they deem appropriate. Sometimes, this is a two week advance notification (very rare occasions), sometimes it is 4 or 5 months in advance (the average is about a 2 to 3 months advance notification).
