Issue link: https://iconnect007.uberflip.com/i/1513827
40 SMT007 MAGAZINE I JANUARY 2024 Feature Article by Bob Wettermann When a PCB undergoes multiple heat cycles, inherent risks emerge, primarily due to the expansion and contraction of materials. is thermal stress can induce various issues, including delamination, warping, compro- mised solder joints, and damage to heat-sen- sitive components like integrated circuits or capacitors. To counter these risks, one approach involves a unique process called "cold mill- ing," designed to mitigate the adverse effects of additional thermal stress. Unlike traditional methods involving direct heat application, this solution utilizes a laser-guided precision mill to remove components. is ESD-safe process includes a vacuum nozzle that simultaneously removes debris during the milling process, ensuring cleanliness. e genesis of "cold milling" stems from a customer's challenge with removing under- filled BGAs. ey encountered issues with underfill leaching into the adjacent solder dur- ing reflow, causing solder shorts. By utiliz- ing this cold milling process, we were able to remove the component without applying heat and place a new component in its place result- ing in a yield >90% and a successful solution for the customer. Cold Milling as an Alternative PCB Component Removal Method