The Proto stage in the NPI Process involves creating prototype devices and finalizing the product design. Prototypes are tested and evaluated to ensure they meet the requirements and specifications as outlined in Product Requirements Specification. During this stage, there will often be several adjustments and modifications to the design.
The Proto stage often involves creating a small number of units (1-10). Only rarely will complete units be built – and if they are, they are often non-enclosed devices (NEDs), wire-wrapped prototypes, or systems assembled out of existing off-the-shelf development kits. Mechanical components are often quickly prototyped, such as with a 3D printer. “Looks-like” prototypes may be created, but lack any actual functionality, while the “works-like” prototypes are often too large to fit into the target enclosure at this stage.
There is often little-to-no testing that happens at the Proto stage. If there are tests, they are usually for informational purposes only, and not for preventing units from leaving the line.
NPI Process Flow
- The Proto stage begins once there is a Product Requirements Specification and engineering resources are assigned.
- The Proto stage is completed once there is enough confidence in the design specifications and approach.
- After the Proto stage is complete, EVT begins.
Related Concepts
References
- NPI Process
- Hardware engineers speak in code: EVT, DVT, PVT decoded – Instrumental by Anna-Katrina Shedletsky
The Proto build is a small test run of key product concepts to gain confidence that they can work — potentially a combination of different form factors including looks-like and works-like.
Purpose: to understand risks around specific modules or designs, usually with multiple variants in low quantities, such as:
- Fragility of coverglass in drop test with different adhesives, perhaps done on dummy housing bucks
- Waterproofness of five different button seal designs
Typical Quantities: 10 or fewer, sometimes no “full systems” are even built
- Parts may be “stand-ins” or rapidly prototyped (which may change results for better or worse)
- Sub-modules do not have to be integrated — units may be “works like” or “looks like”
Things that Go Wrong:
- Part quality is poor, resulting in incorrect dimensions or an interference was missed in the CAD (3D model), so parts do not fit together and have to be modified by hand
- Pin 1s on connectors were not correctly mapped, so things do not electrically work even when plugged together
- The intended design fails miserably during testing and needs to be redesigned
Exit Criteria: one design concept for the product that the team has reasonable confidence is three major iterations or less from a mass-production worthy design