| “Ask and you shall receive,” like “Make your thoughts known,” have the same objective, to initiate a dialogue between someone with a vision and those who can get the job done. In other words, if you don’t ask for it, you’re probably not going to get it, and the moving force behind it all is communication. Communication is as important in design engineering as it is in marriage.
Last time we learned that a system is a combination of interacting components organized to achieve one or more specific purposes and that communication is a key ingredient in the process. Now let’s see how the systems engineering approach is used within the medical device design process. The systems engineering approach consists of five key stages, the first being Concept. In this stage the objective is to identify all stakeholders, that is, those who have a stake in the outcome, then exhaustively define and capture their requirements. Crucial to this stage is a good line of communication between design engineers and stakeholders. This usually takes the form of brainstorming sessions in which all parties meet to toss around ideas. These ideas eventually solidify into design requirements. Once the design requirements are identified, they are incorporated into the first draft of a working specification. This specification will be written using plain English to minimize any potential misunderstandings. Within the specification each requirement is not only well defined, but traceable back to whoever proposed it. To this end, all requirements are listed in tandem with the names of stakeholders proposing them. Accountability is the main concern here. Next time we’ll talk more about these design requirements, and how they must serve the needs of functionality, performance, and constraint. ____________________________________________
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Posts Tagged ‘design requirements’
Systems Engineering In Medical Device Design – Concept and Communication
Monday, December 3rd, 2012
Medical Device Design Controls – Output, Verification, Review, and Validation
Sunday, September 5th, 2010| Recently my wife was on a quest to make the perfect pound cake, but before she put butter to flour she did her research. What’s the best butter? Best flour? Eventually she came up with a recipe she felt would prove to be the Queen of all pound cakes. After the recipe came reviews by her test panel, or family members, including myself. Questions were asked, such as, When you first bite into a pound cake, do you want to be aware of vanilla or lemon? It was only then that she would begin to combine ingredients for the final mouth watering product. Very much this same procedure is used when coming up with a new medical device.
Previously we’ve discussed FDA requirements for medical devices as they concern design controls with respect to design and development planning and design input procedures. We’ll now focus on requirements for Design Output, Design Verification, and Design Review Procedures. Design Output and Design Verification Procedures go hand in hand to ensure that design output is properly documented, organized, reviewed, and evaluated in light of design input. What this means is that medical device companies must scrutinize and evaluate what is going into the design process, then make a comparison to what is coming out. The design is ultimately verified when all requirements for the medical device as previously set out have been met. “Design output” is just another name for work product after major phases of the design project are completed, such as when my wife determined which butter would produce the best pound cake. Design output typically takes the form of specifications, notes, calculations, computer programs, mechanical drawings, electrical schematics, printed circuit board (PCB) layouts, bills of materials (BOM), mockups, prototypes, test data, and test reports. These are then utilized by people outside engineering circles to manufacture components and assemble them into a final product. Design Review Procedures ensure that the design output is evaluated by others not directly involved in or responsible for the design work product, much as when family members served as a reviewing committee for my wife’s inquiries into taste preferences in pound cake. Sometimes she’d even ask a friend or neighbor to put their two cents in, and companies, too, will at times go outside and hire consultants to perform this function. By so doing, unbiased opinions are sought out, in the hopes that this fresh set of eyes will be more likely to spot errors, omissions, and misinterpretations that could prove disastrous if put into play. Design reviews are typically conducted after each major phase of a design project is complete. Just as a recipe that looks good on paper may not necessarily taste good, a device design will often seem to work perfectly on paper, then prove otherwise when its manufacture begins or it’s used in the field. Ideally bugs are worked out before the product hits production and, later, the marketplace. Design Validation Procedures make use of prototypes for testing and careful evaluation under simulated or actual use conditions. Does the design safely meet requirements for intended use? Does it conform with industry standards? If not, there’ll be a lot of wasted “dough” going into the trash — pun intended! Next time we’ll explore FDA requirements for Design Transfer and Design Changes. We’ll also talk about procedures for Design History Files. _____________________________________________ |
Medical Device Design Controls – Planning and Input
Sunday, August 29th, 2010| Have you ever had the divine experience of remodeling a major-use room of your house? Was the general contractor you employed able to understand what you wanted, plan out the work according to your requirements, and finish the job to your satisfaction? Maybe you had the unfortunate experience of hiring one that forgot your requirements, made things up as they went along, and stuck you with a room that looked awful, violated building codes, and didn’t meet your needs.
Now imagine what would happen if a medical device company took this haphazard approach to designing new products. Suppose the company’s engineers ignored the input of regulatory, marketing, procurement, quality control, and manufacturing staff? What if they chose not to follow applicable industry standards for performance and safety? And what if they failed to check design calculations or test prototypes for errors before putting the device into production and introducing it to the marketplace? The result is likely to be unfavorable, just like your contractor forgetting that you wanted a black granite countertop, not a beige one. To help eliminate painful and costly scenarios such as these, the FDA requires that medical device manufacturers establish and maintain procedures to control the design of Class II and III devices, and even some Class I. This requirement for a system of design controls is part of the Quality System Regulation (QSR) under Title 21 of the Code of Federal Regulations. In case you’re not too familiar with the Code of Federal Regulations, Title 21 gives the FDA legal authority to regulate food, drugs, and medical devices in the United States. So what falls under the premises of FDA design controls? Well, the FDA requires that a medical device company develop procedures for:
For now, let’s focus on Design and Development Planning and Design Input Procedures. In the Design and Development Planning Procedure companies must carefully plan who will be involved in each phase of product development, as well as how they will interact, all in an effort to ensure that information flows and design requirements are met. The right pool of people would include design engineers, in addition to those employees responsible for making sure that regulations are complied with and those who are charged with securing intellectual property rights to the design. Then there are those who must acquire the physical materials required to manufacture the device and those who will do the actual manufacturing of it. Also, those responsible for quality control, marketing, sales, and product service should be involved. Perhaps others should be involved as well. Mind you, the Design and Development Planning Procedures are not set in stone. They must be regularly reviewed and updated as the project evolves. Now let’s talk about Design Input, which is another term for a design requirement. These inputs can come from inside or outside the company. An example of a requirement coming from within is when Marketing stipulates that the maximum manufacturing cost of the device should not exceed $150 in order to maintain an acceptable margin of profit and be most competitive in the marketplace. A design requirement coming from outside the company would include industry standards that make specific requirements, such as requiring that the device in question be designed to protect its electronics from radio frequency interference. Next time we’ll continue our discussion on medical device design by exploring Design Output, Design Verification, and Design Review Procedures. _____________________________________________ |
