Overview of the hardware product development stages: POC – EVT – DVT – PVT explained

Hardware is hard...but not impossible

The hardware and IoT product development process is long and costly, possessing challenges and pitfalls to neophytes and those who underestimate the associated risks and project staging. In this article, we break down help to crack the product design and engineering development  into the phases and milestones that any professional design house or new product development company or engineers use.

In a nutshell, the new product development life cycle is divided into 3 major phases:

1. Idea, Product Definition, Feasibility, Conceptualization 
2. Development and Prototyping
3. Volume Production 

There is a whole range of acronyms standing for various types of hardware prototypes in between Concept and Mass Production (MP). In the development and Prototyping phase, there are different prototypes being made and they all serve very different purposes.

Whether you are building a smart IoT speaker, a robot, an electric bike or a consumer kitchen appliance device, you will have to progress via these phases and achieve POC - EVT - DVT- PVT milestones in your venture, otherwise learning the cornerstones of the design process would cost you a lot more time and money and will overshoot the estimated budget. Below is a ‘how to’ plan that is applicable for any product development and manufacturing project.

Demonstrators and Mockups

‍While the first phase of concept development and product definition is very important, it is not much dependent on engineering. At this first stage, making various look-alike demonstrators and mock-ups made of available materials such as paper, clay, plasticine, wood with the help of glue and scotch tape is highly beneficial to channel consumer-centric thinking as early as possible. Industrial designers can practice their creativity and deliver various sketches and renders that are far from the final prototype appearance, but this is all to help thinking and frame upcoming design development. 

Proof of Concepts (POCs)

‍Strictly speaking, any product engineering starts from a POC (proof-of-concept) prototype. The purpose of the POC is to prove the fundamental concept behind the product at the lowest possible cost. That is why POC prototyping highly benefits from market available development kits such as Arduino and Raspberry Pi or hardware/software development kits (HDK/SDK). In deep/hard tech projects that are focused on commercializing a scientific technology, the term POT (proof-of-technology) is typically used.

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One should differentiate POC and MVP (minimum viable product) that are very often confused in hardware development. POC functionality is limited and is NOT identical to the final product, while hardware MVP is a prototype which can be presented/sold to real customers to gather valuable product feedback.

Development and Prototyping

‍EVT – DVT – PVT acronyms stand for the different stages of product engineering and industrialization. These phases of prototype development exist to minimize risks, defects, errors, bugs and design flaws before entering mass production. It is extremely important to identify and cope with these risks during the engineering design phase, otherwise producing and selling 1000s of faulty products would cost you a lot more in money and reputation. 

The table below combines the most common terminologies used for product development lifecycle:

The EVT (engineering validation testing) phase

‍Succeeds the first POC prototype. EVT phase takes up a series (or even a small batch) prototypes of various modules (or subsystems). EVT is all about developing work-like and (sometimes) work-like + look-alike prototypes to validate, test and refine the core functionality of the product. These prototypes can be anything between a breadboard electronics prototype, PCB(A) and functional prototype with a 3D printed enclosure. EVT is intrinsically iterative and several iterations can be made before you eliminate design flaws through functional testing and analysis.

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The objective of the EVT is to combine look-alike and work-like subsystem prototypes made of intended components to meet the functional requirements in the form factor as per your PRD (product requirements Document). 

EVT prototype quantities: 3-50 units, depending on the design complexity and BOM cost. On average, 5-12 prototypes are required to complete the EVT.

Technologies: 3D printing, laser cut/milled PCBs, soft tooling (silicon molds), professional hardware development kits (HDK), rapidly cut/milled parts;

Outputs / Deliverables: fully-functional prototype with key components performing as intended.

Limitations: Prototypes delivered throughout the EVT phase may look somewhat ugly, raw and have a lack of beautiful cosmetic finish. The EVT prototype can also miss some non-key mechanical features such as handles, curves in enclosure, painting, etc.

Only after completing the EVT phase one really pushes on with the industrial design to develop the product final appearance. Any industrial design (whether done in renders, sketches or in CAD) before that stage is not relevant to the actual sizes, weight and module arrangements. The late alpha “work-like + look-alike” prototypes intend to realize the real look of industrial design.

The DVT (Design Validation Testing) phase

Serves the need to validate the developed product’s design and start to implement DFM (design for manufacturability) along with other DF-X rules. After completing  EVT prototyping, one should lock on to deliver the design of the prototypes and enclosures that look like the final product. For example, if you are building an all-weather outdoor meteo station, the DVT prototype should be water-proof at this stage. 

It is the last stage before commencing sales and one needs to make sure the design is compliant with the various standards and certification requirements for targeted markets: CE, EC, FCC, UL, RoHS, etc. And here again, it is important that your product comply with the electric current source before you finalize the design and apply for certification (which you better think ahead when defining your product in a PRD).

There can be several DVT iterations, and different DVT prototypes can be delivered. These range from hand-crafted expensive prototypes with a fine finish to a small batch produced with “quick” and/or conventional steel moulds in the injection moulding machine.

Thus, initial outcomes of the DVT is what we would refer to as the MVP.

The objective of the DVT is to fix the design (i.e. dimensions, weight, materials, finish, moving mechanical parts) and rationalize the final product’s features. 

1. At this stage you should carefully revise and consider features vs product quality/finish vs production and BOM cost vs production volume. 
2. Complete the necessary certifications;
3. Develop and finalize boxing and packaging
4. Commence to request RFQs from mass-producers and devise plans for logistics.

DVT prototype quantities: typically 20-200 units, depending on the design complexity and BOM cost. The prototypes will be used for various reasons: certification lab tests, “beta tests” with early customers/testers.

Technologies: 3D printed + gel-coated enclosures with the finish “as from the factory”, rapidly cut/milled parts; industrial equipment (e.g. injection moulding) and 1st generation tooling (e.g. “quick moulds”).

Outputs / Deliverables: a [batch of] functional prototypes ready for mass-production with BOM and a design documentation package. Boxing and Packaging design completed. Estimate mass-production yields 

Limitations: The DVT prototypes and documentation is nearly final and can be slightly changed further in development. Some mechanical parts and electronic components may not be final due to economic reasons (e.g. it is cheaper to CNC mill some metallic parts instead of using dye casting).

If you plan any crowdfunding campaign such as Kickstarter or IndieGoGo, do not risk your reputation by showing off the POC or early EVT prototype to backers. The EVT phase can be long and require a lot of R&D. So it is important that you present your MVP / DVT prototype that has been engineered and tested with users. With successful crowdfunding, you can fund your final design adjustments and easily and quickly enter the PVT and pilot production

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The PVT or Production Validation Testing

‍Is the last step before officially commencing to mass-production. Usually 5-10% of the production run is delivered in the PVT, aiming to stabilize the quality of the manufacturable product. 

Although the PVT is not the most expensive stage, the outcomes may have a crucial impact on quality and the cost of volume production. Only minor changes are allowed at the PVT. Any significant change in design kicks the project back to DVT.  

Prototypes released at this phase are also called “Betas” and samples acquired from the mass-producer referred to as “goldens samples”.

The DF-X undergoes some corrections which result in mould and tooling development. Test benches for PCBA tests are designed. All components, materials, packaging and logistics are planned at this stage. 

PVT objectives:

1. Verify mass-production yields;
2. Finalize DF-X with the help of CM aiming to minimize waste and make assembly more efficient;
3. Make the first pilot production run and ensure the product quality adheres to your expectations;
4. Weed out the last design flaws during the pilot production run;

PVT prototype quantities typically range between 50 and 500 in order to verify mass-production yields and provide product samples.

Technologies: Industrial technologies suitable for volume production only;

Outputs / Deliverables: Final product produced in a limited quantity by using the tools for mass-production. Electronic layouts and components are revisited using PCB stencils for soldering components. Mechanical DFM is finalized and plastic parts are manufactured by using 2nd generation moulds.

Duration: 3-6 months in general.

Limitations: The time required to design and produce custom tools is generally long.

Mass-production (MP)

‍or MP1 for the first volume run on the manufacturing/assembly lines. This means that you have placed your purchase order (PO) and agreed on the production quantities with the CM

MP1 is typically started from 1000-2000 units which undergo quality and functionality testing. This is ensured via QC (quality control) and QA (quality assurance) measures.

Now you are left with the “simple things” which are sales, customer support and service, dealing with product returns and defects and thinking about the next product version.

And do not forget about the end of lifecycle (EOL) which entails following various disposal procedures and waste management protocols while thinking of replacing your old product with a new SKU!