This industry is not friendly to newcomers. The FDA Waterfall diagram either makes no sense or I'm just a dummy
Relax. You are certainly not a dummy. This industry can be challenging for newcomers, but aren't they all?...
The FDA waterfall model is very old, and while generally speaking it's still in effect / applicable, it has gathered tons of nuance and interpretation over the decades. There is nothing straightforward in all of this, but on the other hand it's doable. Just breathe...
The only thing I know for sure is that if your final product will be built by an automated process, then you can't build your test samples using a manual process!
Not necessarily. It depends on what you're testing, to what purpose and in what stage.
To follow the FDA Waterfall Diagram, you need to perform Design Transfer at the end. But wouldn't you want to perform manufacturing process validation before Design Transfer, so that you can manufacture your test samples for design verification and design validation?
- After all, FDA states in their Design Control Guidance that the design validation “should involve devices which are manufactured using the same methods and procedures expected to be used for ongoing production”.
- And then in the FDA website for Inspections of Design Controls, it clearly states that "Process validation may be conducted concurrently with design validation. Production devices used in design validation may have been manufactured in a production run during process validation."
To all of the above, I have a simple answer: Yes and no. An alternative answer: It depends.
There isn't really a textbook answer that suits all cases, and although some of it might seem contradictory, it's not necessarily so. Some steps happen in parallel, partially, and more than once, every time on a different level of intensity etc. Some of the statements and guidance really don't make sense when read with no context/experience (as you would expect from a patchwork body of knowledge that built up non-linearly across >30 years), but on the other hand in most cases it kind of settles out somehow, when you try to work out a specific case. It's much easier if you have a mentor around.
