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13 commonly used test methods for PCB

PCBs are widely used in all kinds of electronic devices, whether it is mobile phones, computers or complex machines, you can find circuit boards.

Defects or manufacturing issues with the PCB can cause the final product to malfunction and cause inconvenience. In these cases, the manufacturer will have to recall the devices and spend more time and resources fixing the fault.

Therefore, PCB testing has become an indispensable part of the circuit board manufacturing process. It finds problems in time, assists the staff to deal with them quickly, and ensures the high quality of the PCB.

There are 13 test methods commonly used in PCBs.

Online Test (ICT)

ICT, that is, automatic online testing, is an essential test equipment for modern PCB manufacturers and is very powerful. It mainly detects the open circuit, short circuit, and all parts of the PCBA through the test probe, and clearly informs the staff.

ICT has a wide range of use, high measurement accuracy, and clear indication of detected problems. Even workers with average electronic skills can easily handle problematic PCBAs. The use of ICT can greatly improve production efficiency and reduce production costs.

Flying Probe Test

Flying probe testing and In-Circuit Testing (ICT) are both well-recognized and effective forms of testing, and both are effective at finding production quality issues, but flying probe testing has proven to be a particularly cost-effective way to improve board standards .

Contrary to traditional testing methods where test probes are fixed in place, flying probe testing uses two or more separate probes that run without fixed test points. These probes are electromechanically controlled and move according to specific software instructions.

Therefore, the initial cost of flying probe testing is low, and it can be done by modifying the software without changing the fixed structure. In contrast, the initial fixture cost of ICT is higher, so for small batch orders, flying probe test is cheaper, but ICT is faster and less error-prone than flying probe test, so for large batch orders , or ICT is more cost-effective.

Functional Testing

Functional system testing uses dedicated test equipment in the middle and end of the production line to comprehensively test the functional modules of the circuit board to confirm the quality of the circuit board. There are two main types of functional testing Final Product Test and Hot Mock-up.

Functional tests typically do not provide in-depth data (eg, pin locations and component-level diagnostics) to improve the process, but require specialized equipment and specially designed test procedures. Writing functional test programs is complex and therefore not suitable for most circuit board production lines.

Automatic Optical Inspection (AOI)

AOI uses a single 2D camera or two 3D cameras to take pictures of the PCB and then compares the board photo with the detailed schematic. If the board does not match the schematic to a certain extent, the mismatch of the board will be marked for inspection by a technician, and the AOI can detect the failure problem in time.

However, the AOI test will not supply power to the circuit board and cannot detect 100% of the problems of all components. Therefore, AOI is generally used in combination with other test methods. The commonly used test combinations are

AOI and Flying Probe

AOI and Online Testing (ICT)

AOI and functional testing

X-Ray Test

X-ray test, that is, X-ray inspection, uses low-energy X-rays to quickly detect circuit board open circuits, short circuits, empty soldering, and missing soldering problems.

X-ray is mainly used to detect defective circuit boards with ultra-fine pitch and ultra-high density, as well as defects such as bridges, missing chips, and dislocations generated during the assembly process. It can also use tomography to detect internal defects in IC chips. This is the only way to test the quality of ball grid arrays and solder ball bonds. The main advantage is the ability to check BGA solder quality and embedded components without spending a fixture.

Laser Detection

This is the latest development in PCB testing technology. It scans the printed board with a laser beam, collects all measurements and compares the actual measurements to preset acceptance limits. The technology has been validated on bare boards and is being considered for assembled board testing. This speed is sufficient for a mass production line. Fast output, no fixture, and unobstructed vision are its main advantages; high initial cost, maintenance and usage issues are its main disadvantages.

Aging Test

Aging test refers to the process of simulating the various factors involved in the actual use conditions of the product to carry out the corresponding condition strengthening experiment for the aging of the product. The purpose is to test the stability and reliability of the product in a specific environment.

According to the design requirements, the product is placed under specific temperature and humidity conditions, and the simulated work is continued for 72 hours to 7 days, the performance data is recorded, and the production process is reversed for improvement to ensure that its performance meets the market demand. Aging test usually refers to electrical performance test, and similar tests include drop test, vibration test, salt spray test, etc.

In addition to the above 7 tests, based on product requirements, other test methods will be used to further ensure PCB quality. for example

Solderability Testing Ensures a strong surface and increases the chance of a reliable solder joint

PCB Contamination Testing Detects high levels of ions that can contaminate circuit boards, causing corrosion and other problems

Microsection Analysis Investigate Defects, Opens, Shorts, and Other Failures

Time Domain Reflectometry (TDR) Finding faults in high frequency boards

Peel Testing Find out the strength measurement needed to peel the laminate from the board

Solder Float Testing Determining the Thermal Stress Level a PCB Hole Can Resist

PCBA testing is a necessary process that, if done correctly, can prevent quality issues from damaging a brand when a product goes to market.

Fragility Test

Secure solid surface and additional formable break-point opportunities.

PCB Pollution Test

A large number of contaminated circuit boards can be measured, causing corrosion and other problems.

Microanalysis

Check for faults, open circuits, short circuits and other faults.

Time Domain Reflectometer(TDR)

Development board failure.

Stripping Test

Measure the strength required for stripping and pressing on the board.

Floating Test

It is a necessary process to ensure the PCB hole resistance is a PCBA test heat stress level.

About Wonderful

Shenzhen Wonderful Technology Co., Ltd. is China’s top model and small batch circuit board manufacturer.

The company targets precision circuit board samples and small batches as the main target market. Since its establishment, it has adhered to the development concept of good quality and important reputation.

Invest huge sums of money to introduce advanced equipment, strictly regulate the operating standards and QC standards for incoming and outgoing materials, to ensure that the shipped products reach Seiko quality.

The self-developed ERP management system can realize the whole process of paperless operations such as online ordering, online payment, online production progress query, online logistics tracking, and online statistical report production, which greatly improves work efficiency.

It ensures that each order can be shipped quickly. After more than ten years of development, the company’s products and services have been well received by the market.

As well as the opening of an electronic component mall, integrated circuits, semiconductors, resistors, capacitors and other products are sold.

The company’s scale is developing rapidly, and the sample and small batch shipment capacity reaches 500 models/day.

The products are widely used in communications, medical equipment, industrial control products, aviation, military products, testing instruments,Automotive, computers and other peripheral products.

We will continue to pay attention to customers, with efficient delivery speed and perfect after-sales service, to become the most trusted brand supplier in the PCB industry.

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13 Commonly Used Test Methods for PCB