If you’ve ever been asked to sit through a product design review, you may realize that it can range the gamut, from a rather simple email review to a multi-day formal product design review. We asked one of our engineers to share their experience with product design reviews, including what to expect and lessons learned.
Some initial observations of the process include:
Here is a look at a simplified product design review process focusing on requirements, preliminary design and detailed design.
Requirements
This is the first step in the product design process. Setting requirements helps define product goals. Some requirements may be very formal sounding, with legal speak such as “will” or “shall”, while others may be a bulleted list. In either case, it should list broad features without taking into account the actual design, but should be specific where needed. Examples of things to have requirements for include:
When doing a systems requirements review (SRR), invite all team members. It’s important to get as much information and feedback at this stage. At a minimum invite the following key players:
The preparation for a SRR may just be a list of requirements, it can have some sample competitor information or even a demo of a similar product. During the SRR brainstorm and compile all ideas – at the end of the review you will determine what stays and what goes. After the list has been compiled, create an updated requirements document to start the product design portion of development.
Keep in mind that it’s typical for feature/function requirements to conflict with target cost. When it can apply, a requirement should state what is minimally acceptable and what the ultimate goal is. Usually, due to costs and development time, the final solution will be somewhere in between.
Preliminary Design
Using the requirements document as a guideline, it’s time to start the product design phase. At this point, you will probably find that some things are easy to do, some things are very difficult and some of the requirements just don’t make sense. Don’t put too much effort into the design at this point, just make sure you can present a plan to everyone involved that can be completed. Identify major components that will be used and major features such as size, connector locations, look and feel of any software screens, etc. at this stage. Create a block diagram and a very high-level bill of material (BOM). Don’t focus on resistors or capacitors unless they are expensive parts during this phase. The goal is to present the planned design to the whole team to make sure nothing was forgotten and everyone agrees.
Preliminary Design Review (PDR)
This needs to have more material than the SRR, but as long as the product is not too complex, a presentation of the data along with supporting documenting should suffice. Some elements to include:
Be sure to invite include all (or at least most) of the engineers that worked on the job, test people if applicable, users and again others that can provide value. Debate what is required, then update the PDR package to include all accepted changes. It is very likely that there will be some disagreements at this time. Decide which ones have to be resolved now, and which can be marked as action items and document them.
Detailed Design
Once the preliminary design is more or less agreed upon, start the detailed design. This phase involves selecting all components in detail, paying attention to tolerances, power handling, etc. For electronic printed circuit board (PCB) assemblies, full schematics, layout files, and BOMs should be determined. For mechanical components, full CAD or 3D files should be completed. Some bread boarding should have been done to test circuits. 3D printed or machined mechanical components should have been built to test fit. If software or firmware is needed, it should be complete to the level that was agreed upon. In reality, most of the time, everything is not perfect, but deadlines are forcing the design to be complete anyway. In this case, make a list of things that are not quite right, but can be tweaked later.
Critical Design Review (CDR)
The CDR is the final design review before production begins. If it will be short, go ahead and invite everyone (engineers, users, marketing, etc.). This stage may involve some heavy technical discussions. If this is the case, break it up into two sections:
Some elements to include:
Depending on the product, this may be a couple of hours or a couple of weeks. It is important to gain consensus as the next step is production. You may decide to go back and do some redesign, proceed as is or build some units to be able to field test, allowing you to then make changes.
Successful Product Design Reviews
Whether it is a SRR, PDR, CDR, or any of the other types of product reviews, strong communications throughout the product design process is critical so that issues are addressed in real time. A good design review process up to this point will produce the best first production piece possible.
ACDi is committed to helping our clients get their functional products to market as quickly as possible. If you need assistance from our engineering team to help facilitate that process, contact us today.
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