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I recently spoke with Kelly Dack—CID, CID+, and a PCB designer and instructor who has worked in the design and manufacturing segments over the years. Thanks to his background, Kelly provides an intriguing viewpoint on cost-aware design and the philosophy of design economics in general.
Andy Shaughnessy: Kelly, you’ve written about cost and profit in PCB design. Give us a basic overview of your thoughts on design economics.
Kelly Dack: Considering cost in design is tricky because there are so many facets of cost. First, it’s expressed in product development as “time-to-market.” How much is a company losing by not having this product? It depends on priorities. I’ve always said that the first priority is meeting a performance specification and then meeting a cost specification. But in this tricky industry, if you miss either constraint—cost or performance—you may not have a product.
And rarely do I see a cost constraint on the front end of a PCB design project. In fact, I just had a conversation with an engineer regarding using a new chip and a new sensor to drive down the cost of a product, which has been on the market for years. Here’s where it gets tricky: You may not necessarily save money by using a less expensive component. Component packages can have many different form factors, and each may require different design techniques, which could offset any cost savings. A proposed new chip may require a more expensive design process, manufacturing process, materials requirement, or all three. It’s never simple. It really requires some good analysis by all of the project stakeholders.
Shaughnessy: Before you begin layout, what are some criteria that you keep in mind for cost-aware design?
Dack: The first thing is to define products by classes. What type of class does the product belong to? Is it a disposable product? Is it a product that has a dedicated use, or is it a product that needs high reliability? These are all different types of product classifications that will play into how much the product should cost.
For instance, a disposable/throwaway calculator that you buy at a dollar store would be presumed to use less costly components, higher volumes, and techniques to reduce the cost so that a profit would be realized by selling the product in volume. However, a spy satellite or a control mechanism in the cockpit of an airplane will most certainly be more costly due to its limited volume of production and it’s higher reliability requirements. The components and parts used in the product have to undergo rigorous testing, which all add cost to the individual components, and that will add cost to the overall product. Then, there are the specifications and regulations that will add to the timeline and cost.
To read this entire interview, which appeared in the April 2020 issue of Design007 Magazine, click here.