Issue link: https://iconnect007.uberflip.com/i/1475604
10 DESIGN007 MAGAZINE I AUGUST 2022 With the supply chain problem showing no signs of letting up, the idea of designing PCBs with fewer materials has begun to take hold. So, as we mapped out this issue on con- serving materials, we knew it was important to hear from Happy Holden about this topic. Here's why: Happy has been a proponent of cost-aware PCB design for decades. At HP, Happy helped develop the relative cost index (RCI), which allows PCB designers to compare the costs of PCB structures and their alternatives (see page 18). With this in mind, we spoke with Happy about the potential benefits of designing for material conservation, and why many of the old design concepts may be ripe for updating, such as the 0.062" board. Material Conservation Demands Stakeholder Buy-in Barry Matties: Happy, in the past you men- tioned that 75% to 80% of the cost of the board is controlled by design and just 20% by the fabricator. To help designers control cost, you developed a relative cost index. Tell us about that. Happy Holden: We came up with the relative cost index because it was almost impossible to get fabricators to provide cost predictors. First, they didn't want to have people hold their feet to the fire in case you le something out. Second, they were unsure if the informa- tion would get out to their competitors. So, we came up with the relative cost index. It allows you to compare architecture design alterna- tives as a percent savings or percent increase in cost from that fabricator. It doesn't give you the absolute value, although the RCIs are calculated based on the costs of a conventional eight-layer FR-4 through-hole multilayer PCB. Matties: So, you have a bench- mark board, and then you're either adding or subtracting based off that benchmark. Holden: In terms of percent- ages, not in terms of dollars. It's only good for that fabrica- tor because some other fabri- Feature Interview by the I-Connect007 Editorial Team