Stephane Morvan Devendra: it depends on where you are in your design process:

* if you are still evaluating options, then Rapid Prototypes are definitely the way to go to quickly explore, evaluate and validate in a cadaver lab context. Say a set of design ideas for an implant design, a set of instruments etc...

* if you are ready to go to series manufacturing, and seek final design signoff I would advise against using rapid prototypes because this validation step does not just validate form, fit and function, it also validate the manufacturing process which turns your specifications into a functional product... In that case, you should probably consider doing a short series run / validation batch that you would test in a cadaver lab, to ensure you would get the same material, the same specs (or close enough) that of series manufacturing.

Evidently, if your chosen manufacturing process is based on rapid prototyping, your approach make more sense.

Devendra Aher PMP® @Stephane : Thanks for throwing more light on this concern. In short, can I conclude prototypes are good to validate form, fit & function? So they are good for design validation but not for process validation.

Stephane Morvan @Devendra: conventional rapid prototypes can be used to validate form and fit, and the most advanced prototypes (w/ the right material) can go a long way for form, fit and function validation.

I also agree with the bit that process validation has to be done anyway (according to MDD 93/42 and 2007:47) using the final manufacturing process.

Pedro Fregoso Devendra,

I am hesitant to answer your question because this question can have multiple answers, and they all could be right.

Things you need to consider are:

• You are developing a device that will be used in humans, not for a school project, consequently your prototype must be as close to the final design as possible, if not, you would be wasting time and money, and perhaps, making the wrong decision from this study.
• The concept of “rapid” is wide open. Speed is important in any project, but the concept of “pay now or pay later” is very important at this point. Take the time to make the prototype in a way that you get from your cadaver study a good sense of confidence that you are going in the right track.
• Consider the expected application for this device. Some devices (i.e., Class I devices) could be evaluated with simpler prototypes than other devices (i.e., Class III devices).
• Do not use the term “validation” when you use prototypes. You cannot validate anything with a prototype. All you are doing is evaluating a concept. You may be able to start evaluating some manufacturing concepts and some packaging designs as well with this prototype, but do not make final decision here either since everything you do on these areas will be considered “at risk”.
• If you are doing “Design Reviews”, I trust you are following “Design Controls”, if so, you will understand the concepts I am describing here.

Hope this help. Best Luck to you.

Devendra Aher PMP® Pedro, yes I had similar confusion about rapid prototyping precisely. Still, with all things being equal till 3rd paragraph (device classes) does it not validate form, fit & function which is design validation?

Pedro Fregoso I am sorry Devendra, but you cannot validate the design of a product using a prototype.
I suggest you refer to the guidelines that regulate your industry for additional details.

Devendra Aher PMP® Thanks Pedro for firm answer, I would refer Design control again.

Devendra,
Rapid prototyping helps you verify (not validate) your concepts and narrow your options down to 1 or 2 solutions.
It is possible to use rapid prototypes for design validation if you intend to use 3D printing (CAM) to manufacture your product.
Not knowing the details on the product intend, I can only speculate.

Devendra Aher PMP® Thanks Mirela.

@Devendra, the answers of Stephane and Pedro really hit the point. It depends on which stage you are in. For new product R&D, prototype really helps by saving research time and cost. We divide new products R&D a few stages. 1st. If your product is in initial concept design stage, you may find a 3D printing supplier to make a printed model, which is only for outlooking and apperance showing. 2nd. If your design become mature, structure and assembly test might be needed, then 3D print, or CNC milling prototypes are useful. 3rd. After that you may need 10 units for real material test, drop test or heat test. 4th, at this stage, design is almost confirmed. 10 to 50 units customized products might be needed for marketing research, and to protect invest before mass production. Hope the answer helps.

Devendra Aher PMP® Thanks Amy for detail clarification. I am still pursuing the design control aspect raised by Pedro, as per FDA guideline.