What is the purpose of your prototype? If the prototype will be used for trade show or ID verification of the new product, we recommend using CNC machining for manufacturing. It can help you to save the new product development time and cost because it is unnecessary to do internal structural design. More over, the prototype surface processed by CNC machining is more suitable for surface treatment. If made by SLS, the prototype surface will not be as smooth as ones made by CNC machining. We propose to use SLA to make the prototype if you don't have the special requirement for the prototype surface finishing.