PCB Test Method

PCB Test Method

The PCB test method includes the auto optical inspection (AOI) and in-circuit-test (ICT)

  • 1.1 AOI（Auto Optical Inspection）：

    The automated optical inspection machine (AOI machine) is a machine that is designed to perform vision inspection automatically. The versatile machine can practically work on any devices that need precise vision inspection.
    It is used to guarantee that the standard of products leaving the line of production is top-notch-without any manufacturing or assembly deficiencies.
    There are three main advantages of AOI machines:

  • To identify errors in the line of production, and quickly send feedback to avoid a repeat of the failure.
  • To contain high-speed effectiveness with time to enable that corrective measures are taken timely.
  • To be fast (easy programming and operation) to enable an inspection to be completed with a reliable result and promptly.

  • 1.2 In-Circuit-Test (ICT)：

    100% ICT has become the common test which most of customers will require. Even if the ICT is not requested, PCB manufacturers will run the test to ensure that there are no circuit problems in their products. The ICT can be performed in terms of:

  • Flying Probe：

    Bare Printed Circuit Boards (PCBs) and PCB Assemblies (PCBA) undergo various tests before leaving the manufacturing area. One of the most popular test methods is the Flying Probe test. A simple way of explaining, the Flying Probe Test (FPT) is an automated system with a small number of probes that "flies" around the top and bottom of a PCB simultaneously to make contact with the test points. In accordance to program set up for the specific board being tested, a flying test probe is moved from one test point to another.
    FPT machines have high precision needles that perform electrical tests to determine if a PCB (component) is in good condition. These tests, by not having the need to use custom tools, are a cost-effective instrument in the early stage of development and low-medium volume production.

  • Dedicated ICT：

    A PCB manufacturer will ask supplier to produce testing tooling for the product. Also, the probes and wires will be ready for each testing point while the tooling completed. The tooling cannot be disassembled and can only be stored in the complete set.

  • Universal on Grid ICT：

    PCB manufacturers need to ask a tooling supplier to produce a universal on grid tester which only has holes for the testing points but without any cable connection. Before running a test, PCB manufacturers need to insert probes on each testing hole and put the tooling on the upper and lower pads of the ICT machine. During the test, the upper and lower pads contact the testing points through the probes to check if the circuit on the PCB is correct. After testing completed, the probes can be disassembled from the universal on grid tester to facilitate storage.