Detection of Voids
X-ray imaging in detection of voids is helpful to a certain extent. A Digital Microscope should be considered to work alongside, and not in place of or as alternative inspection equipment. Manufacturers striving to gain the highest quality should consider X-ray and Digital Microscope equipment as a pair. Detecting voids is a helpful example of this relationship.
During pre-heating, voids can occur due to deteriorated flux. This can result in low flowing solder causing gas pockets.
The surface of flux residue and shine of solder joints may indicate possible voids (Figure 4A and 4B).
X-ray imaging in detection of voids is helpful to a certain extent. A Digital Microscope should be considered to work alongside, and not in place of or as alternative inspection equipment. Manufacturers striving to gain the highest quality should consider X-ray and Digital Microscope equipment as a pair. Detecting voids is a helpful example of this relationship.
During pre-heating, voids can occur due to deteriorated flux. This can result in low flowing solder causing gas pockets.
The surface of flux residue and shine of solder joints may indicate possible voids (Figure 4A and 4B).
During reflow, air current that is too hot and strong deteriorates flux and causes voids (Figure 5A). The specialized BGA inspection lens for the Digital Microscope can work side by side with X-ray inspection, detecting possible voids. Adjusting air current can contribute to the reduction of void occurrence (Figure 5B). X-ray is an important aid for void detection and until now has been considered an alternative and separate solution apart from both stereo and digital microscopy. Inspection of BGA properties and defects should be considered from a combination of potential solution providers.
Judgment of Defects by Exterior Inspection
BGA exterior inspection allows access to the hardest to reach places on the PCB. The highly accessible prism adapter for the Digital Microscope BGA Lens can squeeze between components and look directly at the BGA from the side on heavily populated boards with minute pitches. Utilizing a metal halide bulb (discussed below), will greatly enhance the information retrieved from this style of observation. The following section as well will provide further examples of how specific reflections further support conclusions and information gathering. Without even the aid of X-ray technology it is possible to determine defects caused by over extended pre-heating and reflow (Figure 6).
Common among these issues of over-heating are oxidization and visible damage to the ball itself (Figure 7). Exterior inspection goes beyond defects, aiding as well in the correction of
temperature profiles.
No hay comentarios:
Publicar un comentario