Why don’t you have the contract manufacturer do the prototype build so you can skip this step?
This is a very common question. The simple answer is “schedule and cost”. As a general rule, contract manufacturers can not produce a prototype as fast or inexpensively as a prototyping house. Contract manufacturers are designed by definition for volume production and have put in place processes consistent with that emphasis. Prototyping houses are used to building a few of a particular item and quickly changing. They are used to, and expect that, engineers will be making last minute changes as the design evolves. Contract manufacturers want to design for manufacturability, yet the design has to proven out. In the end, our experience has consistently shown that the fastest, lowest cost method to shipping products is to keep prototyping activities out of (volume) contract manufacturers and to use companies that specialize in prototyping builds.