PCBA Functional Testing

Everything About PCB Functional Testing

Functional Test: A Final Manufacturing Step

Venture Electronics offers a Functional Test (FCT) as the final manufacturing step to prove these complex boards’ correct functionality and reliability while they are still operating. The comprehensive PCBA testing services include AOI digital inspection, X-ray inspection, ICT in-circuit testing, and FCT functional circuit test to ensure the quality of the PCB assembly.

1. PCBA Testing Types

PCBA testing is the most critical quality control process in PCBA processing, which depends on the product’s final quality. So what are the formings of PCBA testing? Please see the following:

• PCBA testing mainly includes the ICT test, FCT test, Burn-in test, Fatigue test, and harsh environment test these five methods.
• ICT test mainly includes the circuit turn-on and turn-off, voltage and current values and fluctuation curves, amplitude, noise, etc.
• FCT testing requires burning of IC programs, testing the function of the entire PCBA board, finding out whether there are problems with hardware and software, and equipping the necessary chips to process production fixtures and test stands.
• Fatigue testing is mainly for PCBA board sampling, the function of high frequency, long time operation, to observe the failure, and to determine the probability of failure of the test, then to feedback the work performance of the PCBA board.
• A harsh environment test is mainly the PCBA board exposed to extreme values of temperature, humidity, drops, splashes, and vibration to obtain test results of random samples, thus determining the reliability of the entire PCBA board batch.
• Burning-in test is mainly for PCBA board for a long time power test, to observe its working condition whether there are faults and defects, PCBA products will be batch factory after the burning test.

PCBA process is complex in the production and processing process. Maybe due to equipment or improper operation of various problems, and cannot guarantee that the products produced are qualified, so it is necessary to PCBA testing to ensure that each product will not have quality problems.

2. What Is PCBA Functional Testing?

Technicians use a functional test (FCT) as the last manufacturing step in PCB assembly. It provides a pass or fails determination before the finished PCBA is shipped. The primary purpose of FCT in manufacturing is to verify that there are no defects in the product hardware that would otherwise adversely affect the product in other applications. The board that needs to be tested must be soldered and then passed through some specific fixtures to simulate the actual use of the board and observe whether the users can use the board naturally when they power it on. This testing allows you to determine if the board is working correctly and accurately. In short, FCT verifies the function and behavior of the PCBA.

3. How To Make The Testing Of PCBA?

PCBA test standard methods, there are mainly the following methods:

• Manual testing

Manual testing is a direct visual inspection method to confirm the placement of components on the PCB by visual inspection, and technicians use this visual inspection method technology very widely. But the number of numerous elements is small, making this method increasingly inapplicable. And some functional defects are not easily detected, and the data is not well collected. In this way, it needs a more professional test method.

• Automatic optical inspection (AOI)

Automatic optical inspection, also known as automatic visual testing, is carried out by a special detector, used before and after reflow, and is more effective in checking the polarity of components. When using this method, it is easy to follow the diagnosis, it is a more common method, but this method is poor for short circuit identification.

• Flying probe tester

Due to the progress in mechanical accuracy, speed, and reliability, professionals have generally welcomed needle testing in the past few years. In addition, now for the prototype (Prototype) manufacturing, low volume manufacturing is required with fast conversion, no fixture capacity of the test system requirements, making the flying probe test the best choice.

• Functional test

It is a specific PCB or a specific unit of testing methods with specialized equipment to complete. Functional testing is mainly the final product test (Final Product Test) and the latest entity model (Hot Mock-up) two.

• Manufacturing Defect Analyzer (MDA)

The main advantages of this test method are low cost, high throughput, easy short circuit, open circuit testing, etc. The disadvantages are that functional testing is not possible; there are usually no test coverage instructions, technicians must use fixtures, test costs, etc.

4. PCBA Functional Testing Services

Types of PCBA testing functions include:

• Flying probe test.
• Functional testing. Board-level and system-level testing, including engineering technical support.
• Circuit wire bonding.
• PCBA conformal coating.
• In-circuit testing (ICT). Development of test fixtures and tests (recommended to be built during PCB prototype assembly).

PCBA inspection has different requirements at different stages. Manufacturers should consider detecting product defects, cost, and examination speed to configure the right equipment.

The functional test is usually the last test performed on a PCBA prototype. FCT Functional Test provides a simulated environment for the PCBA board to obtain various state parameters of the board to check whether the operating information of the board meets the design requirements. The items of the FCT functional test mainly include voltage, current, power, power factor, frequency, duty cycle, brightness and color, character recognition, sound recognition, temperature measurement, pressure measurement, motion control, FLASH, and EEPROM burn-in, etc.