There are serveral progress for making your plastic part conception/designs — the one you choose really depends on what you expect to accomplish with the real part. For example, will the plastic part be subjected to testing? Does it need to be "dressed up" for a trade show? Will it need to meet tight tolerance requirements?
The most common way to make it as a rapid prototyping,these options are SLA/SLS, Vacumm Casting(also named urethane cast),CNC machining and soft tooling. But which is right one for your component? Please continue to read the article.