Final answer:
Functional testing occurs during the testing and evaluation phase of the product development stage.
Step-by-step explanation:
Functional Testing in Product Development
Functional testing is an essential part of the product development stage which primarily occurs post-development of a detailed design. Once the design team has created a detailed design, the testing and evaluation phase begins. During this stage, prototypes are created and rigorously tested against the predefined criteria and constraints to ensure that the product functions as intended and meets all requirements.
The process involves establishing test methods and is closely managed, from setting up test methods to full product testing. This identifies any weaknesses or areas for improvement in the design, sometimes requiring multiple iterations of refinement or even a return to earlier design stages if the design fails to meet criteria.
Through functional testing, the design evolves, and only after satisfactory test results are secured, the product moves towards the manufacturing phase and final production.
The testing ensures that the product can endure real-world usage while meeting quality and performance standards. Inadvertently, this phase influences the product's success and addresses its lifecycle, safety, and customer satisfaction.