I’m trying to understand how manufacturers choose the most practical process when moving from an early prototype toward production.

For a small plastic or metal part, what factors usually matter most when comparing CNC machining, 3D printing, and injection molding?

I’m especially interested in how teams balance:

• prototype quantity

• material requirements

• tolerance and surface finish

• tooling cost

• lead time

• expected production volume

At what point does it usually make sense to stop using 3D printing or CNC and invest in production tooling instead?

I’d be interested to hear how people here make that decision in real manufacturing projects.