PCB Tech - Online test ICT in PCBA assembly

ict online test in PCBA assembly

At present, there are a wide variety of testing technologies used in the field of electronic assembly testing. Commonly used are Manual Visual Inspection (MVI), In-Circuit Tester (ICT), and Automatic Optical Inspection (Automatic Optical Inspection, AOI for short), Automatic X-ray Inspection (AXI for short), Function Tester (FCT for short), etc.

They can be classified into two categories according to whether the PCBA board is powered on: one is electrical testing technology, the other is the end of non-electrical testing, or whether the PCBA is in contact with the test equipment is divided into two categories: one is contact testing In the end, one is non-contact testing technology.

ict online test

On-line tester (ICT), also known as flying probe (probe, needle bed) tester. Its principle is to test the electrical performance and electrical connection of the assembled PCBA board on the board components to check the production and manufacturing lack of money and a technical means of defective components.

The online tester uses a special flying probe to contact the components on the PCBA board that have been soldered, and uses hundreds of millivolts of voltage and current within 10 milliamps to conduct discrete isolation tests, so as to accurately measure the installed resistance and inductance, Capacitors, diodes, triodes, thyristors, window effect tubes, integrated blocks and other general and special components such as missing installation, wrong installation, parameter value deviation, solder joint welding, circuit board open and short circuit and other faults, and the fault is Accurately locate which component or open/short circuit is located at which point.

The biggest advantage of flying probe test is that the market response speed is fast, but the detection speed is slow, which is suitable for testing samples and small batch orders. If the customer asks for a sample, you can choose the flying needle test until the customer makes a large-volume order and then change the needle bed test. This is not the case, eliminating the need for the customer to change the process or cancel the order.

The strength of ICT is electrical defect testing, such as device malfunction or wrong value. Online testing can effectively find various defects and failures during the assembly process, but it cannot fully evaluate the electrical performance of PCBA.

ICT requires customers' PCB design to meet ICT testability design requirements, and it is troublesome to implement the diversified levels of PCBA processing customers. In addition, the more the number of nodes for PCBA testing, the sharp increase in cost, which is mainly consumed in the design and manufacture of needle beds or flying probes, and there is a problem of difficulty in testing. When the number of nodes exceeds the ICT requirement, when the physical size of the PCBA exceeds the ICT requirement, the problem will be more difficult to solve.

The miniaturization of electronic products actually directly leads to the miniaturization of PCBA board design (high-density integration) assembly, and the value of PCBA design for ICT testing will disappear. This means that production and manufacturing will face a large number of potential problems. The PCBA assembly will go directly to the final inspection, which will not only lead to a decline in the qualification rate, but also increase the amount of repairs and fault diagnosis costs, but also cause production delays.