그리고 PCBA 어셈블리 process is very complex. It includes PCB 제작, component sourcing and inspection, SMT 어셈블리, DIP insertion, PCBA testing, and other important steps. Among them, PCBA testing is the most important quality control step in the whole PCBA manufacturing process. It decides the final performance of the product in use.
1. What Is PCBA Testing?
PCBA testing mainly includes five types: ICT testing, FCT testing, burn-in testing, fatigue testing, and harsh environment testing.
1) ICT Testing
ICT testing mainly checks circuit continuity, voltage and current values and their fluctuation curves, amplitude, noise, and other items.
2) FCT Testing
FCT testing requires IC programming. It simulates the function of the whole PCBA board to find problems in hardware and software. It also needs the right SMT production jigs and test fixtures.
3) Fatigue Testing
Fatigue testing mainly takes samples from the PCBA board and runs the board at high frequency for a long time. It checks whether failures appear and judges the chance of test failure. In this way, it can reflect the working performance of the PCBA board inside the electronic product.
4) Harsh Environment Testing
Harsh environment testing exposes the PCBA board to extreme temperature, humidity, drop, water splash, and vibration conditions. It gets test results from random samples, and then it can judge the reliability of the whole PCBA batch.
5) Burn-In Testing
Burn-in testing keeps the PCBA board and the electronic product powered on for a long time. It keeps the product running and checks whether any failure happens. Only electronic products that pass burn-in testing can be mass produced and sold.
The PCBA process is complex. During production and assembly, problems may happen because of equipment issues or wrong operation. This means not all finished products can be guaranteed to pass. So PCB testing is needed to make sure every product has no quality problem.
2. How to Test PCBA
Common PCBA testing methods mainly include the following:
1) Manual Testing
Manual testing means checking by visual inspection. It uses visual comparison to confirm component placement on the PCB. This method is used very widely. But with large quantities and very small components, this method is becoming less suitable. Also, some functional defects are hard to find, and the data is not easy to collect. So more professional testing methods are needed.
2) Automated Optical Inspection (AOI)
Automated Optical Inspection is also called automatic visual testing. It is done by special inspection equipment. It is used before and after reflow soldering. It works well for checking component polarity. It is easy to diagnose and is a very common method. But this method is not very good at identifying short circuits.
3) Flying Probe Tester
Because of progress in mechanical accuracy, speed, and reliability, flying probe testing has become very popular in recent years. Also, the need for test systems with fast changeover and fixture-free ability in prototype manufacturing and low-volume production has made flying probe testing the best choice.
4) Functional Testing
This is a test method for a specific PCB or a specific unit. It is done by special equipment. Functional testing mainly includes Final Product Test and Hot Mock-up.
5) Manufacturing Defects Analyzer (MDA)
The main advantages of this test method are low early cost, high output, easy diagnosis, and fast and full short circuit and open circuit testing. The disadvantages are that it cannot do functional testing, it usually has no test coverage indication, it must use a fixture, and the test cost is high.
3. PCBA Testing Equipment
Common PCBA testing equipment includes ICT online testers, FCT functional testers, and burn-in test equipment.
1) ICT Online Tester
ICT means In-Circuit Tester. It has a wide use range and is easy to operate. ICT online testing is mainly used for production process control. It can measure resistors, capacitors, inductors, and integrated circuits. It is especially effective for finding open circuits, short circuits, and damaged components. It gives accurate fault location and is easy to repair.
2) FCT Functional Tester
FCT functional testing means giving the PCBA board an analog operating environment, such as excitation and load. It can collect the state parameters of the board and check whether the functional parameters meet the design requirements. The main test items of FCT include voltage, current, power, power factor, frequency, duty cycle, brightness and color, character recognition, sound recognition, temperature measurement, pressure measurement, motion control, FLASH programming, and EEPROM programming.
3) Burn-In Test Equipment
Burn-in testing means simulating the aging process caused by different factors in real use conditions. It is a process of strengthened testing under set conditions. Based on the PCBA board of the electronic product, long-time power-on testing can be done to simulate customer use and carry out input/output testing, so that performance can meet market needs.
These three types of test equipment are common in the PCBA process. PCBA testing during the PCBA assembly stage can make sure the PCBA boards delivered to customers meet the design requirements. It can also greatly reduce the rework rate.
