If you are reading this post, you probably understand the basics of prototyping early in the product development lifecycle. In past posts on prototyping, we have discussed the Proof-of-Concept Prototype and the Design Prototype (also referred to as the Form/Fit/Function Prototype) as the first two phases of prototypes in world-class product development. Let’s define these two prototypes again as a refresher:
Proof-of-Concept Prototype: First phase of a product prototype that bears little resemblance to the final product but is used to validate of the idea and prove feasibility. A Proof-of-Concept Prototype is also used for obtaining intellectual property and to show to investors for raising money.
Design Prototype: Second phase of a product prototype that has the functional and aesthetic properties of the final product and is produced using quick fabrication methods. A design prototype is used to work out the final design and manufacturing details and to receive feedback from distributors, buyers, and retailers.
Note that these first two prototype stages are meant to prepare the product for production but that no production tooling or final products using the final manufacturing processes have been built or qualified. The picture below shows the proof-of-concept (POC) and design prototype for the Emada Cigar Clip, a product that is used by golfers and boat enthusiasts to hold their cigars. The POC prototype was constructed using an off-the-shelf plastic wire clip attached to a flat metal plate and an off-the-shelf magnet. The Design (Form/Fit/Function) Prototype was designed to the specifications required of the Emada and machined out of nylon to meet the functional and aesthetic requirements. These two prototypes were used to prove the concept, qualify the design, and verify it was acceptable for the existing market. This was required to prepare for the next phase of prototyping. The inventing blog Ideas Uploaded provides some other great examples of Proof-of-Concept Prototypes in the post How Inventors make Prototypes.
There is a third and final prototype stage that fills the gap between prototyping and full scale manufacturing. This is referred to as the Production Prototype.
Production Prototype: The third phase of prototype that is fabricated using the final production design and manufacturing methods. A Production Prototype is used to qualify manufacturing processes and to receive feedback from distributors, buyers, customers, and retailers.
The Production Prototype for the Emada Cigar Clip in different materials is shown below. Due to the expectations of large production volumes of this product, it was necessary to produce a two-cavity hardened steel tool for plastic injection molding. Once the tool was complete, the engineering team at Leardon Solutions approved the tool by performing first article inspection (FAI) and determining the process capability (Cpk) of the molding process. To determine the proper material to be used in the final product, three materials were molded including nylon, POM (polyoxymethylene), and PP (polypropylene). All three materials were tested but only the nylon was qualified as acceptable for use in the expected environment.
You might be wondering why you must build production prototypes if the production tools and assembly line are functioning. There is sufficient work required to qualify the product functionality and the manufacturing processes to prevent defective products from getting into the hands of customers. Performing the proper verification and validation with production protoypes will result in high quality products.