Supplier wants to perform pre-qualifications prior to every run instead of locking in parameters.

[Vobro]

I am currently working to validate a process with a supplier. The ask of the supplier was to perform validation. During the OQ, it was asked that non-critical parameters be locked in. Supplier says that they cannot do this, and typically they do not perform OQs. They said they will compromise and run an OQ but will not lock in non-critical parameters.

Typically the supplier runs what they refer to as a pre-qualification prior to each run. Based on the large variability in the raw material, they sometimes need to adjust parameters in order to produce acceptable product.

Questions I have are how does the supplier determine what their critical process parameters are? If they are going to be changing other parameters the affect the output of the process, are these parameters not critical? Does anyone have any experience with this? Is there some way to mitigate the large amount of variability in raw material, in order to validate the process?

 

[Johnny Quality]

Vobro,

In order to give a proper answer I think we'd need to know what the process is. However, have you asked your supplier on why the variability in the raw material is so great they have to adjust/tamper the process with each run? Could it not be improved?

 

[Vobro]

It is a blow form molding process, the variability in the raw material cannot be changed. The supplier says that the raw material variability is dictating certain run parameters and that they cannot be locked in. I have asked about process studies to create some sort of run window, but the supplier says the window would be on a lot by lot basis.

 

[optomist1]

your supplier is not controlling monitoring, managing, validating, etc its suppliers...what does their "pre-qualification" consist of?

 

[Miner]

Just to elaborate on the OP's supplier's situation, I was in a similar situation decades ago. Our process was the co-extrusion of multiple batches of different natural rubber compounds. Natural rubber comes from trees, so the best you can do to minimize variation is to purchase from the same plantation. The rubber compounds were mixed at a sister facility. The variation in the NR polymers caused a lot of variation in the properties of the batch (e.g., viscosity), which caused a lot of variation in the extrusion. While we could lock in 80-90% of the extruder process parameters, we had to use the remaining (critical) parameters to compensate for material variation every time we changed a batch of rubber.

There have been great strides in AI and automated control systems that may be able to automate this now, but then it was entirely manual.

 

[Vobro]

your supplier is not controlling monitoring, managing, validating, etc its suppliers...what does their "pre-qualification" consist of?

From the information I have gathered thus far, their pre-qual is basically a guess and check. The supplier has some locked in parameters but will have to tweak others in order to create the final product. They perform this at start-up of each production run and analyze the components produced, until they are meeting specs for the final product. They then begin the production run with those parameters locked in.

 

[Golfman25]

Jumping on Miner's post, and not all that familiar with blow molding, but in the injection molding context, today's machines can maintain a certain injection speed and automatically alter pressures to achieve that as material viscosity changes. So you could give a range for the speed and let everything else "float." A lot will depend on their equipment. If they know what they are doing and have proven themselves, I would let them be the experts you're paying them to be.

 

[Matt's Quality Handle]

It is a blow form molding process, the variability in the raw material cannot be changed. The supplier says that the raw material variability is dictating certain run parameters and that they cannot be locked in. I have asked about process studies to create some sort of run window, but the supplier says the window would be on a lot by lot basis.

Have they documented the starting point, or method in obtaining their critical parameters? I worked in sheet metal stamping, and there were critical parameters that changed due to material variation, and possibly environmental factors.

I would look at how their setup process is documented and controlled. Do they have a starting point? A defined method in "dialing in" their process? Appropriate controls on the first piece to verify that they have a good setup?