how to predict warranty returns???

[Arvind]

Hi All,

we market products which are covered under warranty (18mnths), a unit once failed under warranty would be replaced by another unit.

The details i have is monthwise total shipment quantity (which may consist of several build month units) and total warranty returns per month.

Alternately i also have what are the build quantities per month and monthwise returns for every such build month.

I tried using Nevada format for shipment Vs failures but realised that the failing components must correspond to that particular month shipment, for which unfortunately we do not have data.

Can anyone suggest me what may be the best way of predicting total warranty returns for 18 months for either each month shipment quantity or build quantity.
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[David]

Hi Arvind,

So if I understand correctly...You have the number of units shipped and the number of warranty returns for each month. However, you do not know from which month's shipment the return came. Is this correct?

[Arvind]

Hi David , you are right i do not know which shipment month the returned units belong to.

But i have details of build quantity per (i.e, how many units are built everymonth)& build month wise returns (i.e., how many units from each build month are returned in subsequent months)

However shipment quantity may consist of several build month units.

pl ref the attachment with my previous post.
Request your inputs please.

[David]

Hi Arvind,

Unfortunately, I do not see a document attached to your previous post. But if you have the build dates for each shipment and you know the build date for each returned unit, then you can conduct a warranty analysis based on the build date using the Warranty Folio in Weibull++. For each build date you could then predict the returns for any desired period of time.

Now if you really want results in terms of the shipping date, this becomes a little more difficult since you do not have the returns in terms of the shipping date. Assuming that the unit does not degrade between the build date and the shipping date, you can simply account for the difference between the two when entering the data into the Warranty Folio. For example, if the shipping date is two months after the build date you would add two months to the build date (or subtract two months from the return date). This will put your data in terms of the shipping date. Although, I think adding two months, in this case, to the build date would be easier than having to subtract the difference from the returns.

I hope this helps.