Prototyping is one of the most exciting and satisfying stages of product development. Typically, at this point the product specification is well defined and a risk management plan has been completed to identify which critical aspects of the design need higher focus. This particular phase of a project can vary from the design of a complete device or a portion of a system. There are a few things you need to consider when designing and developing your prototypes to make the process go as smoothly as possible.
1. Keep your overall cost in mind
Material selections and manufacturing processes are usually driven by the cost goals of the product. The piece part cost of a machined part is much higher than the cost of a molded or cast part. However, there are significant tooling dollars associated with molded or cast parts. If the volumes are high enough and the tooling costs are amortized over the life of the product, molding the part is still the most cost-effective approach for high volume products.
2. Utilize multiple prototyping methods if needed
If casting is not an option there are several options to manufacture metal components besides conventional machining. With the onset of 3D printing (DMLS), parts can be manufactured in record time (often next day) in various materials. If the metal parts are thin there are other options like Photochemical Machining. This process yields parts that have the same material characteristics as a machined part and results in an accurate burr free part. In parts requiring close tolerance round or square holes there is Electrical Discharge Machining (EDM). Production times are typically longer than 3D printing, but the finish quality and accuracy is better.
3. Inventory management is key
When prototype parts arrive, there is much to do. Parts need to be counted and checked against the drawings used to fabricate them. In some cases, parts may need to have post processing done to complete the parts. Occasionally, the client may be providing some of the components used in your design, in which case you will need to verify that they too, are within specification.
4. Be prepared to change your design
Prototyping is the point where one can verify all that was done and conceived in the digital world, works and goes together as designed. There is nothing more gratifying then getting it right the first time. However, things do not always go as planned and when it does not, parts might need to be modified slightly, or in rare cases redesigned, to make the assembly work as conceived.
There may be a requirement for life cycle testing of the product. This can take quite some time depending upon the product and complexity. On some projects there may be tissue, animal or cadaver testing required to see that the product performs as intended. Depending upon these results changes may be required and then portions of the process is repeated.
In other cases, there may be an industrial design phase of the project where after the device is determined to be performing as intended it may need to be altered to have a more ergonomic feel. Sometimes this may be done earlier in the project and other times it may be done in the later phases.
Often there are two to three different concepts to prototype in order to see which mitigates the risk most effectively. Whether it be a full-blown model with machined parts or a portion of the product using rapid prototyping methods, or a combination of both, the goal is to prove out a particular function. While more carefully planned and executed it is still an iterative process. Keeping a calm head while you work through these iterations will allow you to develop your prototypes on time and within budget.