From Concept to Bestseller: How Products Mature Through Sample Phases

A -- B -- C -- D -- this is how the German Association of the Automotive Industry (VDA) designates the sample phases in product development.The VDA defines these phases in its recommendation for maturity level assurance of new supplier parts in the product development process, to regulate cooperation between suppliers and vehicle manufacturers.(Reference: Verband der Automobilindustrie e. V. (VDA), Quality Management Center (QMC): Reifegradabsicherung für Neuteile -- Methoden, Messkriterien, Dokumentationen. 3rd revised edition, June 2022. Berlin: Verband der Automobilindustrie e. V. ISSN 0943-9412.)The VDA has good reasons to think carefully about cooperation between vehicle manufacturers and their suppliers.To have safe, reliable, and fully functional vehicles in the showroom and ready for customer delivery by the set market launch date, standardized procedures and unified communication terms are not just helpful but necessary.A vehicle isn't just any product where you can accept if something isn't quite perfect. Faulty vehicles pose a safety hazard to people and can cause potentially disastrous economic damage.I know what I'm talking about.During my time as development manager, I had to deal with recall actions and safety-relevant product defects -- a dubious pleasure one would gladly do without. Nevertheless, this experience proves valuable in emergencies, as you then know how to act quickly and professionally to get such problems under control.Controlling product development through maturity levels and structuring development projects into sample phases aims to avoid quality problems in customer use and recalls.However, the price for this careful, classical approach is a development time of ten years or more.Despite all necessary care, such long development times are no longer sustainable today. Market demand and competitive pressure require significantly shorter timeframes to bring new, innovative vehicles to market.I have intensively studied how to accelerate vehicle development without compromising quality in recent years.This has resulted in a framework I call "NewPDP" -- New Product Development Process.I will write about these approaches in upcoming articles. I hope they will be helpful not only for vehicle developers and developers at automotive suppliers, but also useful in other industries.So please subscribe to my newsletter so you don't miss any article.In this article, I'll start with an overview of the project phases and lay the foundation for understanding the processes that build on them.Sample Phases in a Development ProjectThe term "sample phase" comes from a time when product development was heavily influenced by working with hardware.It wasn't that long ago when computers were fed with punch cards and many problems couldn't be solved theoretically.Even today, we can't completely avoid empirical work. This is evident from the fact that the VDA itself published a revised edition of its recommendation in 2022.The basic approach to product development is as follows:* Define requirements* Find solution (design)* Document solution* Manufacture parts* Build a prototype* Test prototype* Identify errors* Analyze error causes* Correct the errorsIn the classical approach, this sequence is run through multiple times -- called "development loops." With each loop, the product works better and becomes more "mature."Since parts are manufactured, prototypes assembled, and tested in each loop, there are as many hardware development stages as development loops -- the classic "samples" that get their letter designation according to project phase.However, these loops are the cause of long development times.If we want to accelerate development, we need a different logic.However, multiple phases where the product matures still make sense.In my interpretation, the classical sequence isn't run through completely multiple times in succession, but only once. Selected problem areas are worked on and completed sequentially to keep complexity manageable during troubleshooting.Manufacturing parts in a high-volume production process requires very high investments and costs. This makes it necessary for the product to already have high maturity at the time of investment, otherwise high change costs can occur.As a consequence, this means development must predominantly occur without the presence of final parts.As described initially, the VDA focuses on components and delivery scopes developed by suppliers and made available to vehicle manufacturers. However, the sample phase logic has found its way into the basic project structure of vehicle development projects through this approach.I will explain my interpretation of the individual sample phases here, which follows the basic logic presented by the VDA in some aspects, but has a much stronger focus on accelerated development of the end product.A-Sample Phase: Concept DevelopmentIn the A-sample phase, architectures and concepts are developed. The focus is on the fundamental design of the product.Requirements for the newly developed product are converted into concepts, and these concepts are validated.Typically, no hardware is used in this phase; instead, work takes place in virtual space.To start the A-sample phase, the following information must be available:* Project goals (costs, time, and performance requirements)* The predecessor product and its performance characteristics* Pre-developed new, innovative technologies* Technical specifications of key components (space requirements, calculation models, performance characteristics, integration requirements, etc.)As a result of the A-sample phase, the following outcomes are available:* The dimensional concept is established* Product modularity, and variance are worked out* Installation spaces, part and component positions are defined* System requirements are broken down and system interfaces defined* Development goals for components and parts are established* Software and mechatronics architecture are fixed* Communication protocols, features, and functions are defined and assignedAt the end of the A-sample phase, it must be ensured that the product concept, as defined, can fundamentally function and contains no unsolvable tasks.This also includes ensuring that the conceptually established technologies are well enough understood that they can be brought to series readiness.To clarify this aspect, it may occasionally make sense to test such technology in hardware. Normally, however, this should already have been done earlier as part of a pre-development project.The actual A-sample is a virtual prototype consisting of:* Carryover parts and components from the predecessor product* Space envelope models of parts and components to be developed* Concept models of parts and componentsConcept validation occurs on these virtual prototypes using CAD and CAE. In the A-sample phase, Systems Engineering is a focus, so that in addition to space envelope models, System Engineering Models are also created and used.Should it be necessary to manufacture and measure or test hardware for concept validation, this is done manually with minimal use of tools and fixtures. However, the functionality of prototype parts must enable assessment of concept suitability.At the end of the A-sample phase, the development goal is clear and feasibility is validated.B-Sample Phase: Function DevelopmentIn the B-sample phase, systems and components are developed. The focus is on the functionality and performance of the product.Now it gets concrete.Based on the A-sample phase results, the completely functional product is now created, which theoretically achieves all project goals.Unlike the VDA proposal, I don't have "the" B-sample.Here we have a special feature in my approach that differs significantly from the VDA approach.The B-sample phase begins with the A-sample, which continuously evolves during the B-sample phase and is documented as the C-sample at the end of the B-sample phase.It's somewhat odd that a change in process logic occurs here. The result of the A-sample phase is the A-sample. However, the result of the B-sample phase is not the B-sample, but the release of the C-sample.You can think of it this way: the large development loops from the VDA approach take place as micro-loops within the B-sample phase.This phase is characterized by iterative development steps that lead to the final product design.Because relatively little time is usually available, as many scopes as possible must be developed using theoretical approaches and calculation tools.Where working with hardware prototypes is unavoidable, these are manufactured very pragmatically oriented to concrete development needs, with minimal time and cost expenditure.The B-sample is a virtual prototype that continuously evolves throughout the entire B-sample phase.For development tasks requiring hardware prototypes, "mules" are used. These are physical vehicles equipped only sectionally with hardware B-sample parts. The scope of B-sample parts is tailored to the concrete development task.At the conclusion of the B-sample phase, all product, system, and part specifications are established and there are no more open questions or problems.The end of the B-sample phase is also an important milestone for suppliers, because now the requirements and execution details of their delivery scopes are completely described.To explain it clearly, I like to use the comparison with a school exam:At the end of the B-sample phase, paper and pencil are collected, the exam is over.The teacher's correction of the work is now comparable to the C-sample phase.Software represents a special case.Since software doesn't require high investments in production equipment, software functions can also be developed later. However, this only applies to functions that have no influence on product hardware validation.C-Sample Phase: Reliability VerificationIn the C-sample phase, the reliability and durability of the new product are validated. The focus is on searching for development-induced quality defects.In this phase, proof is now provided that reality really matches theory and no errors or misjudgments have occurred.For this, complete, representative, physical prototypes are needed.For this reason, the beginning of the C-sample phase involves manufacturing product prototypes that exhibit all project change scopes in their interaction and full functionality.The danger is still great that problems will be recognized in this phase. Therefore, the change effort for necessary design modifications must be kept minimal. However, the prototypes must represent the state of the later series product as well as possible.Two different methods are typically used for part manufacturing:* Relatively cost-effective prototype production methods are applied. The compromise lies in the possible production quantity. With these methods, usually only a small quantity can be manufactured.* Preliminary stages of later series production equipment, combined with higher manual manufacturing effort, are used to manufacture the prototypes.The number of C-samples depends on the requirements for statistical validation of change scopes. This is a big topic that I will address in separate articles.I must say it feels very unusual when the entire project team should pause until prototype parts are manufactured and prototypes assembled.This somehow feels inefficient. But it's not!Validation is only meaningful and informative when what is validated is also manufactured exactly that way. Design changes are prohibited until concrete errors are recognized and analyzed. These may be corrected through changes.Software is again an exception here. During the time hardware is procured and C-samples manufactured, additional software functions may be developed.Once C-samples are available in hardware, product validation in theory and practice begins.The C-sample phase ends with the decision to make investments in series tools and series manufacturing equipment. This is formally expressed through D-sample release.Now it must be clear that nothing more can go wrong and the product functions as required.D-Sample Phase: Series Capability VerificationIn the D-sample phase, the series suitability of the product is validated. The focus is on series production-induced quality defects.Similar to the C-sample phase, the D-sample phase also starts with creating D-samples.D-samples are characterized by corresponding to the series manufacturing state because they were manufactured in the series manufacturing process.Why is this needed at all?Hardware has the characteristic that manufacturing methods can have a significant influence on part properties.The size and type of influence strongly depends on the manufacturing method and chosen prototype method.If this interests you, write it in the comments, then I'll write more about this topic.The D-samples themselves emerge so late that testing can usually only take place alongside series production.It's quite reasonable to consider this, as it offers the advantage that possible problems are found before they occur at the customer, and thus prophylactic error correction possibilities still exist.Another special characteristic of hardware is that the error occurrence probability follows a bathtub curve. Errors don't all appear immediately. Particularly impairments in operational strength only appear after some time in use. So there's still time to fix the error before it occurs.I can also go into more detail on this topic if it interests you. So write it in the comments.For parts and components, an A/B test is performed on test stands, checking whether the D-sample part exhibits the same properties as the C-sample part, which was tested in the overall system.At the end of the D-sample phase stands series release, often also a Chief Engineer release, which approves the product for sale and customer use.Sample Phases OverviewLet's return to the development sequence presented at the beginning.Unlike the classical approach, in the NewPDP approach the sample phases don't designate development loops where the development sequence is completely run through.They bracket segments of the development sequence and define which aspects of product development are focused on in the respective phase.With that, I'll conclude today's overview of the development phases of vehicle development. I will certainly go into more detail on each phase in separate articles and also present the concept of maturity levels. Maturity levels are very closely connected to sample phases.I'm aware that this subject matter is very specialized, so I'm very interested to know whether this information is helpful to you. Please give me feedback on this!Please also write in the comments which aspects I should go into more detail on in upcoming articles.We can also chat about it.Don't forget to subscribe to my newsletter so you don't miss any of the upcoming articles.If you found this helpful, don't forget to share it with others who might enjoy it too!If my newsletter resonates with you, please consider sharing it with others. Get full access to Uwe Mierisch at uwemierisch.substack.com/subscribe