The key differences between spin forming and deep draw stamping for making rapid prototype parts are as follows:

Spin Forming:

Spin forming, also known as spin casting or spin molding, is a metal forming process that involves rotating a flat metal blank against a rapidly rotating form tool to create a symmetrical 3D shape.
This process is well-suited for rapid prototyping of rotationally symmetric parts, such as automotive components like wheels, fuel tanks, and engine covers.
Spin forming is generally faster and more cost-effective than deep draw stamping, as it does not require specialized tooling and can be performed on a CNC lathe or dedicated spin forming machine.
The main limitation of spin forming is that it is primarily limited to axisymmetric shapes, whereas deep draw stamping can produce a wider range of complex, non-symmetric forms.
Spin forming works best with ductile metals like aluminum, brass, and copper.

Deep Draw Stamping:

Deep draw stamping is a metal forming process that involves using a punch and die to progressively shape a flat metal sheet into a desired 3D form.
This process is well-suited for rapid prototyping of complex, multi-part metal components, as it allows for the creation of intricate shapes and features.
Deep draw stamping is typically slower and more expensive than spin forming, as it requires the fabrication of specialized tooling (punch and die), which can be time-consuming and costly, especially for low-volume prototyping.
The main advantage of deep draw stamping is its versatility in producing a wider range of non-symmetric shapes and forms compared to spin forming.
Deep draw stamping works best with malleable metals like aluminum, steel, and brass.

In summary, spin forming is faster and more cost-effective for producing rotationally symmetric prototype parts, while deep draw stamping is better suited for creating complex, non-symmetric metal prototypes, although it requires more specialized tooling and is generally slower. The choice between the two processes depends on the specific design requirements and the desired turnaround time for the prototype.