What was the first design for manufacturing (DFM) tool used in the printed circuit board (PCB) industry? Answer: The eye loop. Yes, back in the day when design organizations sent actual photo-plotted 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. Eye loops were used until the 1990s to check PCB artwork for manufacturing suitability. Simpler times, then. 10 mil lines and spaces. 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 are 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, in many cases outsourced and off-shored. So what does DFM look like today? Well, it’s become more than DFM for one thing. 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. LINK