Design vs. Production Trade-offs through the Lens of Modularity

Engineers promote modularity and code reuse when developing software, writing FPGA code, and designing hardware. Even modern EDA software packages take advantage of reusable modules at the schematic capture and PCB layout stages. Often, functional reuse is encouraged to reduce the design phase of a product and achieve faster time-to-market.

But the world of engineering is not limited to design. Design teams must also consider procurement and operations. Modularity can be crucial well after the product is designed and fielded to customers. This is not without its tradeoffs.

If a system contains two customized circuit boards which each have a component that requires passive heat dissipation, it would behoove the designer to take the extra steps to ensure both boards share the same heatsink mounting footprint. However, while a modular thermal solution with repeated use on the second PCB benefits the designer with reductions in design time and file management, the procurement team may also see a benefit: Purchasing a higher quantity of a single unit will increase the likelihood of a price break, thereby increasing profit margins of the system for the corporation.

Like all decisions, this comes at a cost which could be observed both in production and engineering.

After units are fielded, should a customer discover a flaw in the mounting threads for the heatsink, then all heatsinks must be remachined, stalling the production lines for both circuit boards. Whereas, if each circuit board were designed with a unique heatsink tailored to fit, a fault in one design would be less likely to impact the other, and the line assembling the circuit boards without the faulty part may resume.

The modular heatsinks in our dual-circuit board system could also come at the cost of reduced functionality to the customer.

Back at the design house, the engineering team may have elected to use the same heatsink to cool chips of two different manufacturers, each with different heights. The heatsink is designed optimally for the taller of the two parts, where the part makes direct contact with the heatsink using a low resistivity thermal compound. To accommodate the shorter part, a thermal gap pad is utilized, which has a higher thermal resistivity, resulting in reduced performance of the part.

At the Engineering Design Group, we work closely with our customers to understand their design goals. Whether they seek a short design cycle, optimum heat transfer, or factory operating efficiencies, our team will be paying attention to the design trade-offs throughout the design process as we work with you towards the solution.