Whether a supplier is able to make a prototype for your business is completely dependent on the specific supplier. Some suppliers may only provide 3D prints of prototypes, which isn't necessarily a problem, but could pose a challenge for businesses that want both a 3D printed prototype and mass production of that prototype to happen in the same factory.
If businesses are looking to manufacture their product based on a 3D printed sample, then you need a supplier that has CNC capabilities. It can be difficult for businesses to find suppliers who can make prototypes (as well as the kinds of prototypes they want to make), but Kanary makes this easy. We've already vetted prototype suppliers, so we can offer the best (and most cost-effective) supplier choices to our clients.