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As technology evolves and PCbas become more complex, careful consideration must be given to the testing and inspection options for these boards. PCB is a key component and is expected to work well in a variety of environments. Appropriate testing procedures and inspection measures are required to maintain product quality and reliability.

PCB inspection and testing benefits

Having a trusted contract manufacturer is one of the most critical steps to successfully building a board. The company prides itself on providing high quality products to its customers. This is achieved through many years of repetitive PCB assembly and manufacturing processes. We pay close attention to preventative measures and pre-construction steps, rather than finding problems after the fact and reworking to fix defects. The most commonly used inspection and testing methods experienced by the company are:

Visual examination

Automatic optical detection

X-ray examination

First piece inspection

Online test

Functional test

Aging test

PCBS come in a variety of shapes, sizes and quality requirements. They can be rigid or flexible, single-sided, double-sided, multilayered, and so on. The industry also uses three "categories" to classify PCBS and PCbas. They are Level 1, Level 2 and Level 3, of which Level 3 is of the highest quality and requires the most attention.

PCB assembly

As the category requirements increase, so does the complexity of the inspection and testing methods. Both PCB manufacturing and PCB assembly require a unique set of inspection and testing methods to manufacture the board to specifications.

Visual examination

The most basic form of inspection is a visual inspection. This is done by having technicians inspect the circuit boards with gilt plates, bills of materials and prints. Then, special personnel check whether there are wrong components, missing components, welding bridge, missing welding, monument falling off and other errors. You can use magnifying glasses, powerful microscopes and, of course, good lighting. Because this method is highly operator dependent, it can be time consuming for large and complex boards. This is mainly done at the end, but it is important to visually inspect the board throughout the manufacturing process to verify procedures and procedures. After SMT, we can find out whether the SMT machine misses or mispastes components and solder paste problems. The company uses high power to provide our operators with a variety of light sources and glare free lighting to fully understand the PCBA being inspected. Each lens has an adjustable high-power lens for viewing to minimize eye strain.

Automatic Optical detection (AOI)

AOI uses high-resolution cameras and software to catch manufacturing errors. The software essentially checks multiple images of the board being examined against the "gold" board images stored in its memory and flags the differences.

These machines can be placed on the entire SMT line. Inspection after the reflow welding stage can reveal welding defects, such as dry welding, welding bridge, insufficient wetting, tombstone shedding, etc. The operator can then make more subtle adjustments to the previous stages based on feedback from the machine to ensure fewer defects.

Although AOI technology has come a long way, it still has some weaknesses. On the one hand, AOI is not good at through-hole parts. It can catch many through-hole errors, such as part errors or missing parts, but sometimes poor height, casting shadows, and hiding parts can be limitations of AOI. Programming also takes some time, which is an additional overhead.

X-ray examination

X-ray detection is required for components with hidden leads. There is a pin arrangement below the BGA, and its connection cannot be visually inspected after welding. X-rays are then used to check that all the leads are properly welded.

First piece inspection

In order to verify programs and components, the OEM usually needs to conduct a first inspection of the product. The company's fixed asset investment plan is different. Some require CM to verify the completion of the FAI in written documentation, others to actually send them the first article for approval. Whatever you think is necessary, it is important to communicate with CM to check all the boxes.

Online and functional testing

Online testing: This form of testing requires a custom fixture, often called a nail bed. Typically, several spring-loaded metal probes are assembled in an array on an insulated bed. If ICT testing is considered to be the best form of testing, it is usually planned at the design stage, as this requires the designer to place the test pad at a key location in the underlying copper wiring of the PCB.

The tester places the assembled PCB on the probe to electrically connect it to the test pad. Sometimes it is manual or built into the light. The test will then check various parameters, such as resistance, capacitance, and inductance between the specified probes, as well as marking differences from established standards.

Functional testing: This approach varies widely. It is essentially a field simulation device. This test form is created by the OEM and given to CM to run. It usually includes a power supply and multiple inputs to ensure that the board works as expected.

Aging test

Burn-in tests can simulate real environments. The PCB components will be set at the maximum temperature for 24 hours and continue for the specified time. After cooling, there should be no expected performance problems. This can be verified by functional testing or ICT.

Our company inspects and tests

We provide inspection and test methods here according to customer request. Whether your board requires multiple forms of testing or several forms of testing, our experienced team is here to help you. PCB factory explains and shares PCB assembly inspection and test options guide, test procedures and inspection measures in detail to maintain product quality and reliability.