PCBA= Printed Cirruit Board + Assembly that PCB board space.After the pieces of SMT , DIP plug in another whole process , referred to as PCBA .For large , high-densityPrinted circuit board Assembly (PCBA, printed circuit board assembly) to develop a robust testing strategy is important to ensure compliance with the design and function . In addition to the establishment and testing of complex assembly , the only input the money in the electronic components may be very high - the final test when a unit may reach 25,000. As such the high cost of assembly to find and repair the problem now than in the past and even more important step. Today, more complex assembly of about 18 square inches , 18 layers ; in the top and bottom with more than 2900 components; with 6000 circuit nodes ; has more than 20,000 solder joints need to be tested .
Manufacturing plants in the accelerated (N. Andover, MA), manufacturing and testing -the-art PCBA and complete transmission system . More than 5000 points in the assembly of a concern for us , because they are close to our existing line test (ICT, in circuit test) equipment resource limits (Figure 1 ) . We now manufacture about 800 different PCBA or " nodes . " In this 800 nodes , about 20 species in the range of 5000 ~ 6000 nodes . However, this number growing rapidly.
New development projects require more complex, more and more closely packed PCBA . These requirements challenges for the construction and testing of the ability of these cells . Furthermore , with smaller components and higher number of nodes and greater circuit board may be continued . For example, now draw a circuit board design , there are about 116 000 nodes , more than 5100 components and more than 37,800 requests testing or confirmation of the weld . This unit also in the top and bottom BGA , BGA is followed by the . Using the traditional needle -bed to test the size and complexity of the board , ICT method is impossible.
In the manufacturing process , especially in the test, the increasing complexity and density of the PCBA is not a new problem . Aware of the increase in testing within the ICT test fixture pin number is not the direction to go , we can replace the circuit began to observe the recognized method . See per million the number of non-contact probe , we found the node in 5000 , many found the error (less than 31) may be due to probe access issues rather than actual manufacturing of the defects ( Table 1 ) . Therefore, we begin to reduce the number of test pins , not rising. However, the quality of our manufacturing process or the assessment of the entire PCBA. We decided to use a traditional X -ray ICT and layered on the Combination is a viable solution.