Trivia question for you: What was the first design for manufacturing (DFM) tool used in the PCB industry? Answer: The eye loop.
Yes, back in the day when design organizations sent actual photoplotted films of their PCB design to the bareboard fabricator, the fabricator would put the received films on a light table and measure feature sizes for line widths, spacing between features and annular ring using an eye loop with a reticle etched onto the glass lens. If the features were beyond the capabilities of the fabricator, the job would be declined and the customer notified. If the film had extraneous features they would be removed with an Exacto knife. Voids would be filled in using a black marker.
Simpler times, then. Ten mil lines and spaces and double-sided PCBs were the norm. Manual DFM was feasible.
Needless to say, our industry has advanced in technology since those days. We have PCBs that exceed 64 layers, build-up technology with laser-formed stacked and staggered microvias, embedded devices, and complex rigid-flex circuits. And our design, fabrication, and assembly processes morphed into the new global economy, and in many cases, outsourced and off-shored.
So, what does DFM look like today? Well, for one, it’s become more than DFM. We now expect our software tools to serve us more completely to take new designs to market. DFM has evolved to become an integral part of new product introductions (NPI). Today’s NPI software spans design and manufacturing to accelerate the optimization of a PCB for manufacturing. It looks at the entire design-to-manufacturing release process and deliverables, then streamlines them.
Engineers at best-practice companies use NPI software to help identify ways to optimize their design during the initial release process, with a holistic view of their bareboard fabricators’ and assembly suppliers’ capabilities. It’s not simply a matter of catching mistakes these days. It’s about understanding the various challenges and limitations involved in the chosen manufacturing processes and then empowering the product owner to make the trade-off decisions that best serve their objectives.
To read this entire article, which appeared in the September 2017 issue of The PCB Design Magazine, click here.