TechnoTronix believes in best practices for PCB assembly rework, which recommend providing Pb-free training kits to aid in instructing technicians and developing profiles.
Accurate and reliable reworks are more difficult in a PB-free environment because the PCB and the components closest to the part needing repair must endure several cycles of higher temperatures. To protect the PCB laminate, the preheat temperature should be set no higher than 10?C below the glass transition temperature of the PCB material. Increased temperatures during this process means you may have to slow down the oven line speed during re-flow. OEM carefully plans for all exigencies during each step in your project.
The next steps involved in the rework process vary depending on whether or not there is a Pb-free requirement. The differences in standard vs. Pb-free present a number of challenges that can only be resolved by introducing new or altered processes including tighter, more accurate thermal profiles and extreme precision throughout the PCB rework procedures. This will avoid a number of costly problems that can result from the varying thermal profiles.