How to test the printing circuit board

 Printing circuit boards (PCBs) are used in almost all electronic products. As a result, the designer continues to promote PCB limitations and engineered integrated circuits with fewer size requirements and other key connections. Therefore, in order to meet the growing demand for connections and rapid advances in electronic manufacturing, PCB component manufacturers must conduct comprehensive quality assurance testing.

Manufacturers will conduct tests such as online testing or X-ray inspection to check components and detect defects in almost all micro packaging. Defects (such as size or power consumption) in the characteristic definition directly affect the single board on which they occur and pose risks to the manufacturing process and the supply chain. The ultimate goal of the manufacturer is to achieve higher output at a lower cost and lower defect rate. Therefore, even occasional flaws can destroy the goal.

This article focuses on various quality control testing techniques in the circuit board manufacturing process.

1 – PCB circuit test (ICT)

Online testing (ICT) is the most powerful PCB testing method. Testing technology focuses on opening, short-circuit, component values, and IC operations. This is a capacitive test.

The online nail bed test consists of a small spring needle that is pressed into each test point to measure the small spring needle. The integrity of the circuit board weld is checked. To start testing, you can push the circuit board down to the probe bed (nail bed). The evaluation board has a pre-designed access point, which allows the on-line test probe to connect to the circuit.

Manufacturers usually use ICTs for mature products that are rarely modified. If you do not set up a proper pad on the board, you cannot carry out ICT. In addition, you cannot change your mind in the middle of ICT production and use.

2 Automatic optical inspection of circuit boards (AOI)

AOI is widely used in manufacturing because it is an automatic test. Compared to manual inspection methods, it has higher speed and repeatability.

Before comparing the picture with the detailed schematic, AOI uses 3D or 2D cameras to take PCB photos. If the circuit board does not match the schematic to some extent, the technician will mark it for inspection.

Do not rely on AOI. It cannot power PCBs, nor can it cover all types of circuit boards 100 %. It is best to use it with functional, flying needles or online testing.

It is particularly useful when placing AOI at the end of the welding plate production line. Here, testing can quickly identify production problems, such as welding defects. When you perform the AOI test immediately after welding, you can quickly stop and solve all problems before the problem affects the subsequent PCB.

3 -Circuit Board Production -Flying Needle Test

This non-electricity test will check the opening, short-circuit, capacitor, resistance, inductance, and diode problems. The test uses a needle that is connected to the X-Y grid probe from basic CAD. Then, your program matches the circuit board and checks for an error.

The difference between a flying needle and online testing is the latter's high initial cost because you need to design it to be suitable for test fixtures. However, ICT is a faster and less error-prone test. Compared to flying needle surveys, ICTs may also be more cost effective for larger orders.

4 X-ray examination (AXI)

AXI is an inspection tool for most electronic manufacturers. Here, X-ray technicians can locate defects in the manufacturing process by looking at the welded connection, barrel, and internal trace line. The AXI test uses 2D and 3D.

The X-ray test can check generally invisible elements, such as the array of ball bearings below the chip package. This test requires a trained and experienced operator. It's time-consuming and expensive.

5 Printing circuit board function test

Manufacturers use functional tests to verify whether the product is powered on. It requires fixed devices and external devices. It must also meet standard requirements (such as UL and MSHA). Customers usually provide functional testing and parameters, but manufacturers can help them design and develop them. Functional tests may take some time, but from a quality and life perspective, they can save you face and money.

6 – PCB board aging test

This is a strict PCB test that can detect early failures and determine load capacity. Due to strength, aging tests may damage other parts. It usually continues to power via PCB with the maximum specified capacity for 48 to 168 hours. This test is not applicable to all items and may shorten the service life of the product.