Copyright © 2014 www.lybga.com. All Rights Reserved. LiYang (LY) Welding Equipment Co., Ltd.
Method for detecting BGA welding
Method for detecting BGA welding
For the BGA is concerned because the chip is welded, it is difficult to judge the welding quality. In the
absence of inspection equipment, the first visual observation of the BGA the most outside of the solder
joint situation (as shown in Figure 2), then the chip to the light, if each column can be determined by the
light can not be determined, and sometimes the size of a large point can also be seen. However, this
method can not be used to determine whether there are other defects in the solder joints or whether
there is a hole in the solder joint. To better judge the quality of the solder joint, the X light spot inspection
instrument is used.
Traditional two-dimensional X-ray direct photographic equipment is cheaper, but the disadvantage is in
two sides of the PCB board all the solder joints are also in a photo developing. For components on two
sides of the same position, the formation of these solder shadows will overlap points not clear which is
the surface of the component, if defective, it is not clear which layer. This can not meet the requirements
for accurate determination of welding defects.
In addition a 5DX HP circuit board inspection instrument is specifically designed to check the solder joints
of X ray tomography inspection equipment. Of course, it is not only able to check the BGA, the circuit
board all the solder joints which can be checked. Although it was previously thought that this device was
too expensive for solder joints inspection cost was too high but with the application of BGA devices more
and more people have been able to accept this expensive equipment. 5DX HP is a X ray tomography,
which can be used to produce the effect of the film layer. The images of X ray tomography can automatically
analyze the solder joints according to the original design data and the user settings. The CAD can be used
to perform a precise comparative analysis of all the components of the PCB. Why is there a very high effect
of X - ray radiography in tomography? This is determined by the principle of its work.
The HP system of the 5DX X system is generated by a X ray tube at the upper end of the device. At work,
the voltage must be raised from 160KV to 200V, and the current is 100mA. An electron beam produced
under high voltage will produce a X ray on the metal tungsten. This a bunch of X-ray diagonal shot down
to 7.6 (Rev / sec speed high-speed rotation, also in the following is not a scintillator platform with the
same speed and X-ray synchronous rotation. The flash device is actually a receiver for X light sensitive.
Generally speaking, metal tin, lead and other heavy metal X light will not through, will form a dark scene
and the general material is X light penetrate what can not see. X light in a position between the light
source and the platform of the flashing device to appear a gathering plane, the aggregation of objects
or images on the platform to form a clear image, but not on the aggregation level of objects or images
on the flash platform is eliminated only a shadow. The principle of X ray tomography is shown in Figure 3.
As a result of the high degree of PCB on different joints of the fault, you want to check a layer of welding
conditions as long as the layer will be adjusted to the location of the plane will be very clear to show the
results of the scan.
TAG:  BGA PCB BGA rework station