What FDM is good at, and what it is not
Good at: geometry, fit, assembly sequence, visual proportion and anything where you need it this week.
Not good at: surface finish that matches a moulded part, material properties that match the production grade and anything where the layer lines change how the part behaves. A printed part tells you whether the design works. It does not tell you whether the moulded part will.
That distinction matters when a printed part is used for a functional test, and we will tell you where the result does and does not carry over.
Other additive processes
Where the application suits it we can arrange SLA for high-detail visual models, and SLS for functional parts that need to behave closer to a moulded component. Tell us what the part has to do and we will suggest the process that suits it.
Alongside a tool, not instead of one
The usual sequence is print for form and fit, simulate to prove the design will mould, then cut steel. Each step costs less than discovering the same problem at the next one.