Once the design concept and cost requirements have been set, it is time to complete the detailed design of our part. This is the time to make a final determination of the material the part will be molded from and select any other components that will be included in the final product (e.g., threaded inserts, screws, etc). For our molded part, the following aspects must be considered.
Often, features that would functionally perform well are difficult and thus expensive to manufacture. Features are sometime added that have no effect on function but facilitate assembly, testing, packaging, etc. An example would be a slot allowing easy part orientation and gripping by a robot. Complexity of part design can effect robustness of the manufacturing process, tooling maintenance, etc.
Part appearance can be affected by many things to include part geometry, material, the molding process, and mold construction. If it is important for the part to have a certain "look", whether shinny or textured, this is the time to make that determination.