Importance of Prototypes in New Product Development

The word prototype has its origins in the Greek words prōtos ‘first’ and tupos, ‘figure’ or the ‘defining characteristic of something’. Therefore, we are basically dealing with a first, or at least an early, effort to represent all or part of a new product idea.

Prototypes are created for a number of reasons:

  • Make an idea or product vision tangible
  • Evaluate an idea when analytical techniques or typical design practice are not applicable
  • Demonstrate functionality and performance, retiring technical risk
  • Refine product usability
  • Visualize cost drivers

A prototype is a representation of a product idea intended to
learn something about the ultimate end product

Prototype complexity and finish exist over a wide spectrum from limited to fully detailed functionality, and from low-fidelity (basic form) to high-fidelity (final product form and behavior).

Rapid fabrication techniques (stereolithography, fused deposition modeling, computerized mold-making and sheet-metal forming services, etc.) enable many physical prototype components to be obtained in hours or days. Occasionally, specialized components such as custom optics will require either alternate fabrication techniques or engineering approximations based on off-the-shelf solutions.

Tensentric has identified four levels of prototype, discussed below:

  • Concept Model
  • Element
  • Functional Demonstration Prototype
  • Engineering Confidence Unit

Protoype Image

Not all types of prototypes will be required for every project, while some projects may require multiple or iterative prototypes for each step of development.

Concept Model

Concept models consist of an iteratively-evolving progression of mockups and prototypes used to explore the usability, form and architecture of product-level concepts.

  • The goal for concept models is to help development teams, stakeholders and end-users envision and interact with ideas at product-scale. -Concept models are early tools for exploring usability and engineering-related issues, exposing potential use errors and opportunities for improvement. -Concept models may expose unforeseen or incompletely-understood requirements and the implications of product constraints, all of which inform the selection and scope of follow-on engineering prototypes.


Prototypes for exploring technical feasibility may consist of individual or connected ‘elements’, sometimes called ‘proof-of-principle’ (POP) devices. Elements generally address a single component or function such as an actuator, a valve, a flexure, a circuit or an optical structure.

Selection of candidate elements is based on risks associated with preliminary performance requirements, architecture tradeoffs, feedback from concept models and project constraints.

  • The goal for elements is to demonstrate performance or function in isolation from other system variables and constraints.
  • Elements have the advantage of being limited in scope, size and complexity and may be more easily designed, fabricated, assembled, tested and modified as needed.
  • Elements are often instrumented to maximize the information that can be obtained through their evaluation.
  • Elements differ significantly in design, components and construction from ‘final product’ in that they exist to answer a limited set of questions, challenge performance limits and refine specifications.
  • Elements are valuable due to their ability to produce rapid results which inform subsequent design.
  • Elements may be interconnected to evaluate or demonstrate more complex systems.

Functional Demonstration Prototype (FDP)

FDPs begin to integrate key subsystems and important interfaces at product-scale.

  • The goal for FDPs is to demonstrate key functionality in product-scale architecture.
  • FDPs typically run ‘end-to-end process’.
  • FDPs define and utilize critical interfaces required by the final product.
  • FDPs may use components suitable for eventual product integration.
  • The level and maturity of software, electronics, mechanics and system integration may vary significantly depending on identified project risks.

Engineering Confidence Unit (ECU)

ECU prototypes look and function like the ‘final product’. ECUs inform final costs, demonstrate required performance and support preliminary regulatory and usability testing.

  • The goal for ECUs is to represent a fully-integrated design meeting identified product requirements.
  • ECUs demonstrate full ‘end-to-end’ functionality and incorporate all critical interfaces.
  • ECU materials, construction methods, fabrication processes and designs may not be ‘final’ due to the constraints of rapid prototyping in small numbers.
  • ECUs are evaluated with respect to product and system requirements and any deficiencies are corrected through targeted, iterative design.
  • All disciplines and stakeholders including engineering, systems, management, quality, marketing, manufacturing, industrial design, human factors and service contribute to ECU development, assembly and/or testing.

Prototypes are tangible representations of the successive stages of development from initial idea to fully realized product. Each level of prototype yields valuable insights into how to create a final design most appropriate to the ultimate end goals of the development project.

Tensentric is a team of highly experienced engineers developing a wide range of medical devices and in vitro diagnostic systems. Tensentric has completed over 200 development projects for clients in the medical device and IVD space since the company’s inception in 2009 and is ISO 13485:2016 certified.