Technology

Three Basics To Understand PCB Inspection

PCB inspection is critical to any PCB assembly and fabrication process. It helps the stakeholder identify any errors, bottlenecks, or glitches in the circuit board that could otherwise significantly impact its performance down the line. It also helps to reveal any design flaws in the PCB. Since PCBs are made of various complex electrical parts, it is necessary that during and after the engineering process, you need to subject it to rigorous testing. It will help ensure that you are releasing a high-quality product in the market that will deliver optimum performance without malfunctioning.

Checking a PCB after each phase in the production pipeline can help you to uncover any defects immediately. It will help you intervene in accumulating the potential flaws and enable you to save time and costs. It ensures that you are maintaining consistent quality among your boards and final products. You need to deploy an effective PCB inspection strategy to gauge the errors appropriately. With a proper inspection procedure in place, you can immediately identify and respond appropriately to various defects. PCB assembly is prone to a wide range of common defects such as opens and shorts, inconsistent orientation, soldering errors, components misalignment, wrong component placement, defective or missing non-electrical and electrical components, and more. If you want to avoid these issues, you should follow a rigorous PCB inspection and testing strategy. 

Through PCB inspection training and certification, you can educate yourself about the various problems you may encounter during the PCB production process and use suitable inspection methods to gauges these issues. It will help you release high-quality PCBs by ensuring that the PCB design meets the documented IPC standards. Effective PCB inspection allows you to help prevent the recurrence of PCB problems, improve circuit board efficiency, and meet customer expectations. It would be best if you inspected the PCB to verify the soldering quality, electrical conductivity, mechanical strength, cleanliness, lamination, hole wall quality, and more. Here are few essential things you should know about PCB inspection.

Benefits Of PCB Inspection and Testing

  • PCB inspection helps to identify and gauge faults and bugs like short circuits, opens, poor soldering, functionality glitches, and more.
  • It helps to find potential issues in the printed circuit board early in the production pipeline so that the stakeholders can rectify problems on time and save money. Eliminating issues in a finished product is more costly, complex, and time-taking.
  • Efficient PCB inspection helps to bring down wastage and costs. It is because, rather than using complete products, testers use small-scale assemblies and prototypes. Hence, you do not have to waste faulty, full-scale circuit board assembly.

PCB Components Tested

The three main components in a circuit board that you should inspect for irregularities and malfunctions include the capacitors, diodes, and resistors.

  • Capacitors: Capacitors store energy in the form of an electrostatic field. It blocks the direct current flow and enables indirect flow current while it simultaneously stores energy. For testing capacitors, apply voltage to identify if it functions correctly. It may be susceptible to short, leak, or compromised working if it does not deliver desired results. 
  • Diodes: Diodes help to transmit current in a single direction and block current in the opposite direction. You need to test the diode with care, hence hire a professional to do so.
  • Resistors: Resistors have two terminals that allow currents to produce voltage. With the help of an ohmmeter, you can test the resistors. Once you isolate a resistor, use a digital multimeter, and connect the leads to the resistor for testing it. If it shows high, it is probably due to an open resistor.

PCB Inspection Methods

  • Manual PCB Inspection Or MVI: It is a simple PCB inspection method. You visually inspect the board to identify potential errors. Compare the PCB design with the blueprint available to ensure it does not have any perceptible glitches. Include the MVI method after each stage of PCB production to respond to common errors immediately. It can help you maintain consistency in board thickness and dimensions and optimize surface quality.
  • AOI PCB Inspection: The Automated Optical Machine (AOI) inspection process requires an optical system. The systems image of an exemplary assembly and compares the two images for detecting problems. The machine utilizes various light sources and one or more still or video cameras to take the image. It helps identify complex defects like bridging, insufficient solder, and damaged parts.
  • AXI PCB Inspection: The modern-day complex PCB includes components and chip packages such as BGAs and CSPs. With Automated X-Ray Inspection or AXI, you can effectively view the solder connection beneath a chip which you cannot perform with an optical system. It is expensive but necessary in various instances to identify solder joints in complex circuit boards.
  • Automatic Laser Test Measurement: It uses laser technology to measure solder joint’s dimension and deposition. It helps define the quantity and position of solder paste deposition and ensure that it is aligned appropriately with the circuit board.

To Conclude:

With proper PCB inspection, you can ensure that the components are correctly placed and function optimally. It will help you minimize waste and maximize board safety. Moreover, it facilitates the release of high-quality products that are at par with the service level agreement.

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