Effectiveness of Different Materials as Heat Shields during Reflow/Rework

摘要

As device density continues to maximize the PCB real estate the reflowing of neighboring components or damaging of heat-sensitive components in the rework process continues to cause problems. Devices either have to be removed, thereby reducing rework throughput, or devices get damaged during the reflow process if not shielded from the heat generated during rework. The shielding solutions used most commonly either cannot be delivered in a timely fashion or offer very limited protection to these heat sensitive devices. A new, flexible heat shielding solution is now available that can be easily modified by the users and is inexpensive enough to have on hand. Most importantly it is an effective way to reduce the temperature on nearby components during the reflow/rework process so that neighboring devices do not go into reflow. This study documents the relative effectiveness of this ceramic nonwoven material as well as different shielding materials in protecting neighboring components during PCB rework.