Issue link: https://iconnect007.uberflip.com/i/1536435
32 PCB007 MAGAZINE I JUNE 2025 Trouble in Your Tank Feature Column by Michael Carano, IPC CONSULTANT In the movie "Friday Night Lights," the head football coach (played by Billy Bob ornton) addresses his high school football team on a hot day in August in West Texas. He asks his players one question: "Can you be perfect?" at is an interesting question, in football and the printed circuit board fabrication world, where being perfect is somewhat elusive. When it comes to mechanical drilling and via formation, can you drill the perfect hole time aer time? Over these many years, I've learned that you cannot fix poorly drilled vias with good plating, and you cannot make perfectly drilled vias more reliable with poor plating. Via formation is followed by desmear and metallization. e quality of the through-hole drilling process (and by inference the quality of the drilled through-hole) or lack thereof will also impact the desmear and metalliza- tion processes. While drilling equipment, tools, and methods have been continually improved over the years, the fabricator must adhere to strict guidelines with respect to maintenance of the equipment, quality of the drill bits, the drilling operation parameters, and the proper selection and use of entry and back-up materials. When simple mainte- nance of drill equipment and drill bits is lack- ing, drilled hole-wall quality deteriorates. is leads to defects in the plated through- hole (PTH) that are not attributable to the plating processes, such as electroless copper. Drilling Basics rough-holes are formed by the cutting action of drill bits in numerically controlled drilling machines. Figure 1 shows a five-head drilling machine. ere are multiple factors to consider when mechanically drilling plated through-holes and blind and buried vias (assuming mechan- ical drilling will be used on a few applications for blind/buried vias). ese include the drill machine, drill bits, entry and back-up materi- Can You Drill the Perfect Hole?