Three resin lots required for part qualification

Hi All,

Been running up against some people who like to require three different lots of resin to do a part qualification. Early in my career I spent some time at a medical molder and they used the three lot requirement. Always assumed it was part of the FDA IQ OQ PQ process but searching online I can't find a mention of it being required.

Does anyone know where using 3 lots to qualify comes from? Trying to understand the background so I can attempt to kill the idea here. Current part running into the "we need three lots" wall is non-medical and is molded with HIPS - boggles my mind. :confused:

Thanks!

I have never had to run three lots of resin, but I am guessing it is to prove the process is stable with changing lots of material. If it isn't something that is a super critical part I would just let the customer know the normal process and that any additional testing costs extra. Found a lot of times customers rethink things when they realize their requirements cost them money.

I work for a medical molder (regulated facility) and we write our PQ protocols to use multiple material lots "if available". The idea of PQ is to model long term behavior of the process and prove it's stable, so varying material is a good challenge. It works fine when using obscure medical grades of engineering resins that come in 50 lb sacks, but for commodities like olefins that you have to buy by the Gaylord (which for small parts may be a ten year supply), it's just not feasible. For HIPS, it would be insane.

First, as far as I know, there is a ISO standard which is used as a regulation for sterilization for medical packaging validation. Three resin lots requirement reffed to this requirement.
Second, the reason why chose three lots resin is to simulate the real production situations. In this way, it could identify materials differences risks.

I've run 3 lots of resin many times, but only if customer requires it.
The work-around is justification of a robust processing window. The argument is if you qualify a higher injection speed + higher pack pressure and a lower injection speed with lower pack pressure (among other parameters) you've covered your basis of any lot variability you might encounter