If my primary goal is a visual model, which process will give the best substrate?
The immediate thought is not to separately source the constituent parts and the finishing. The finish derived is predominantly a function of the model makers skill and as such a lead should be taken from his experience. (This is probably not the time to introduce a new material unless there is a good reason).
As a general rule the softer the material (substrate) the more difficult it is to obtain a high level of finish. For example, it is easier to polish PC clear than it is to even obtain a smooth finish on PP, and it is easier to dress SLA and glass filled SLS than laser sintered nylon.
Process selection will also impact the toughness of the final part, so if a concept model is going on a world tour, in and out of packing cases and customers hands, some of the more fragile resins should be avoided.
The substrate will be responsible for the majority of the models weight. On large models this can be considerable and opportunities usually exist with RP processes to core out areas from hidden surfaces. This can ease handling, storage and carriage and improve durability.
