Underfill Rework Services-Cold Component Removal
BEST can deliver underfill rework services for customers with underfilled components, components in close thermal proximity to underfilled components as well as components close to thermally sensitive (cameras, plastic bodied components such as connectors or thermally sensitive sensors) components.
Removal of a component from a PCB using a typical thermal removal process can create several problems including the pushing around of solder during reflow or the thermal damage to neighboring components.
Instead of using a thermal reflow process BEST has a precision high speed milling machine which can remove a component without sending the neighboring areas into reflow. Through the implementation of precision laser micrometers the mill is able to remove the component to within a few thousands of an inch from the PCB. The high speed mill is programmed to take several cuts at removing the component body, underfill, solder and copper interconnections leaving only the solder in place. The precision is gained by holding the populated PCB to the milling table using a vacuum fixture to insure that it is held as coplanar as possible. This combined with the proper tool sizing, spindle speed and tool travel allows the component to be removed without thermally damaging neighboring locations. An integrated chuck vacuum source and static control helps to eliminate FOD on the PCB and while reducing potential static charging which may damage the PCB. This programmable tool mills locations through fiducial recognition and precision servo motors to precisely locate the component to be removed.
Applications in handheld electronics which utilize underfill to help prevent solder joint cracking if the device is dropped typically have underfilled components. This opens up the possibility of underfill rework of cell phones, laptops, pad computers and other like devices. In addition, automotive electronics which use underfill to protect the components from damage due to shock or temperature are well-suited for this rework approach. Applications in engine or transmission control modules, cameras and position sensors all are well-suited for using this component removal technique.
In addition to not thermally damaging the surrounding area, the automation of the process allows for more consistent yields and potentially higher throughput of PCB rework. This eliminates the potential bottleneck of only very highly skilled technicians working on these projects. It also increases the yield once the process is refined.
More information on the process can be found below: