Prototyping Guide
“If I had five minutes to chop down a tree, I’d spend the first three sharpening my axe”
Prototyping is often misunderstood in the commercial world. Our guide is designed to address some key misconceptions.
The outcome of prototype testing is usually a refinement on the original concept design, but new opportunities for functionality and even wholly new applications can be realised in the early stages of prototyping. Design validation, durability, certification, customer experience, and performance, all of these testing categories serve to expose opportunities to improve the product. The best project managers prepare for this eventuality, both in terms of financial and strategic planning as well as technical problem solving.
A prototype is not simply a first-build of a product. Nor does prototyping represent a single product development phase. Rather, it is an iterative process which extends across much of the product development journey. There is a best practice for developing products that has been realised by the most successful companies in the world. In this guide, we set out the four phases which broadly constitute that vital practice of “Prototyping”.
Phase One: Proof of Concept
Objective
To prove the product’s Core Technology-otherwise known as the “product-critical systems”-is capable of fulfilling its intended function and can be attained by current physical and technology capabilities.
Technology Readiness Level: 3
Stakeholder Duties & Expectations
Directors and Stakeholders are encouraged to amend concept requirements. Multiple updates and refinements are likely within this stage.
Prototype budget quantities:
1 for simple product
2 for complex product
Marketing: None - no public awareness.
Core Technology Status
Core Technology is designed for integration with test equipment. Features may be added or removed to ease assembly or reduce costs. Support systems and integration features will not be representative of a product or meet performance targets at this stage.
Product Status
The overall “Product-Concept” is not yet a consideration, and much of the system will bear no resemblance to a finished product — aesthetics are not a concern here. For ease of development and to minimise cost, systems may be integrated into a simple enclosure or a pre-existing “mule”.
Manufacturing & Assembly Method
The final product’s manufacturing capabilities and limitations should be considered in the design of Core Technology, but in most cases an alternative, cost-effective, ad hoc production method will be employed. Generic assembly methods that do not require specialist tooling will be employed in most cases, and any specialist tooling will be designed for developmental testing only.
Quality Control
Parts designed in-house go through initial quality inspection, while off-the-shelf parts do not. Early quality control is reliant upon engineering judgement, but may employ practices already established in the business. A ‘Faults System’ is implemented to log and track issues, as well as how they are being actioned.
Design Validation & Testing
The function of the Core Technology is validated with reference to the Product Requirements. The Product Specifications will be reviewed and modified in turn, in light of the performance and operation of the technology.
User Experience Testing
UX is not tested. This is limited to lab-based work conducted by the product developer. Ease of replacing components and the like nonetheless remain a consideration here.
Phase Two: Experimental Phase
Objective
Prove through experimentation that an “overall product-concept” meets performance expectations with reference to the Product Requirements. Optimise product durability within simulated environments.
Technology Readiness Levels: 4 & 5
Stakeholder Duties & Expectations
Directors and Stakeholders make final changes and sign-off overall product-concept.
Prototype budget quantities:
- 2-3 for simple product
- 10 for complex product
Marketing:
First rendered concept images are revealed. Initial interest in product is gauged.
Core Technology Status
A design optimised for manufacture undergoes comprehensive performance and durability testing to ensure all Product Requirements are met and fall within available manufacturing capabilities. All core technology and associated support systems must now achieve performance targets.
Product Status
Detailed integration design and aesthetic considerations are now implemented as part of the overall product-concept. While this prototype might undergo further refinement, this design represents a best effort to finalise layout and appearance; it will only be updated if problems are identified during testing or customer demonstrations.
Manufacturing & Assembly Method
Investment will not have been made in the tooling required for mass-production at this stage, and most parts will be manufactured by alternative means. Critical and long lead-time mechanical parts (e.g., castings), however, may nonetheless follow the same mass-production methods, in order to prove key reliability requirements are met.
Quality Control
Quality control processes for the Core Technology are formalised. All Core Technology parts are “inspected to drawing”, to assess manufacturing accuracy and capture issues that could cause failures in testing. Bought-in-parts may rely on external quality inspection. Historical engineering quality control examples are considered for their relevance to the current project.
Design Validation & Testing
Product is tested rigorously against its Requirements, in preparation for certification and demonstration, as in-house testing foreshadows all relevant certifications tests. While sub-system performance tests represent an additional validation phase, they often prove to be cost-effective in the long run.
User Experience Testing
The product developer or stakeholder assumes the role of “user” at this stage—customers do not yet have access. As one of the key Product Requirements, the results of testing inform the development of the user interface.
Phase Three: Demonstration & Certification
Objective
Prove that the Core Technology is robust in real-world environments, using mass-production manufacturing processes. Establish the supply chain and obtain certification. Selected customers test the product and offer their feedback.
Technology Readiness Levels: 6 & 7
Stakeholder Duties & Expectations
No more changes in design by Directors or Stakeholders. Design freeze on whole-product.
Prototype budget quantities:
- 3-5 for simple product
- 5-15 for complex product
Marketing:
Branding details are integrated into the design. Product images and performance figures revealed.
Core Technology Status
Core Technology design is frozen: no further design changes should happen beyond this stage. Testing is only to prove performance and durability improvements are effective. Any future design changes—e.g., if the prototype fails a certification test—can have large cost implications.
Product Status
Overall product-concept layout and aesthetics are finalised. Changes beyond this point only occur to resolve issues uncovered during certification testing, or if an alternative manufacturing method is needed (usually in response to a supply issue).
Manufacturing & Assembly Method
Parts now manufactured by mass-production methods wherever possible, with exceptions assessed and tracked via a Development Specification document. Production supplier contracts are negotiated and signed.
For training purposes, assembly will be trialed by an experienced production team—an invaluable exercise for highlighting minor quality issues or opportunities for refinement. Special tooling is designed and assembly processes are formalised.
Quality Control
All parts undergo formalised quality control processes, with the following structure:
Design approvals >
Supplier and/or internal inspection >
Stores >
Build >
Subsystem tests >
Final assembly >
Full system test
Production logistics including inventory handling are realised for the first time.
Design Validation & Testing
Product certification including CE testing, UN testing, destructive tests, NVH (Noise Vibration and Harshness), and electrical and electromagnetic tests are completed to ensure the product is functional, high-quality, meets safety standards, and incurs minimal environmental impact.
User Experience Testing
Ergonomics tests are conducted to ensure the production product feels, sounds, and functions at the required standard.
Phase Four: Full Prototype
Objective
Prove 100% functionality with zero project issues, including manufacturing quality, production and assembly processes, and customer perception. Save for the employment of mass-production tooling, this prototype is identical to a production unit. Final preparation for commencing production, with focus on quality control processes and full product approval from commercial team.
Technology Readiness Levels: 8 & 9
Stakeholder Duties & Expectations
Directors and Stakeholders champion the mass-production process and focus on improving business efficiency.
Typical number of prototypes:
- 10-20 for simple product
- 5-10 for complex product
Marketing:
Full Prototypes are used for product launches. Initial orders are taken.
Core Technology Status
Core Technology parts and associated support systems are already manufactured with mass-production tooling, with no exceptions. Due to the level of integration with the overall product-concept, any design changes at this stage can incur far-reaching costs and delays.
Product Status
In this final phase of Design for Manufacture, all parts require a subtle redesign, to optimise for the agreed mass-production methods. This necessary change must be validated by stringent durability tests. The discovery of any need for refinement past this stage signals a failure in an earlier design decision and will require full review.
Manufacturing & Assembly Method
Parts manufactured by mass-production method (in 99% of cases), including all long lead-time items. Supply chains are established and tooling orders placed.
Assembly processes are refined and approved, with formal assembly/build tooling used exclusively. As all product part designs are now locked in, this stage represents the last iteration of build tooling.
Quality Control
All parts go through production-level quality control processes and are formally audited. Sub-assembly pass-off testing and whole-product final inspection will be concretised.
Lessons learned during the development phase are captured, for review and application to future projects.
Design Validation & Testing
All validation, durability, and performance test protocols are repeatable and applied to the overall product-concept with consistent results. A baseline is defined.
User Experience Testing
User expectations have been scrutinised and implemented, with details validated and signed-off at a minute level. User experience criteria, including aesthetics and branding, now match the product intent and are identical to a full production unit.
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