Types of PCB Inspection and Factors Inspected Discussed

The printed circuit board assembly process is fully automated and usually performed by experts. Although every step is carefully planned, errors may still be introduced during the assembly process. This is why the PCB assemblies are inspected carefully before shipping to the customer. Do you want to know how this PCB assembly inspection is done and what factors are addressed during the process? This post is all about PCB inspection. It will give you a brief insight into various types of PCB inspections and their importance.

Types of PCB Inspection

PCB inspection is used for detecting faults in a printed circuit board after the manufacturing process. The following are a few popular PCB inspection techniques used by PCB manufacturers to check faults in PCB assemblies:

• Visual Inspection of PCBs: Visual inspection may sound like a straightforward method, but it demands tremendous focus to check hidden errors. In this process, the operator checks the printed circuit board from all angles to fix the mistakes, if any. Technicians also use a magnifying glass to detect the faults in a PCB. This is a very cheap and simple inspecting method that can help in identifying major solder errors. The visual inspection is usually performed after every stage of manufacturing.
• Automated Optical Inspection: Automated optical inspection, abbreviated as AOI, is the same as visual inspection, but it is an optical inspection process. In this inspection method, a camera is used for scanning the circuit board — the scanned images of PCBs help in identifying the defects and catastrophic failure. 
• X-ray Inspection: As the name suggests, x-ray inspection is done using an x-ray machine. This machine provides a precise 2D or 3D picture of a printed circuit board. The x-ray inspection transmits X-rays through the object and records the grayscale images of components. The image is processed by the software, which detects the size and position of the component.

What Factors are Inspected Using Different Inspecting Techniques?

The following factors are checked on a PCB board using various inspection techniques:

• Solderability: The solder helps connect the components to the board. During solderability inspection, the factors like edge dip, wave dip, and ration dip are checked.
• Warpage: Warpage is inspected by applying pressure to the corners of a printed circuit board. This helps in determining any breakage or crack on a PCB.
• Appearance and Size: The appearance of a PCB and its size are checked by inspecting its line width, tracing, layers, sides, and so on. By examining these aspects, one can rely on the physical appearance of a printed circuit board.
• Internal Defects: The PCB assemblies are inspected for internal defects using microsection technology, where factors like lamination, alignment of the layers, copper thickness, etc., are inspected.

The above-given points can help you understand the importance of inspecting a printed circuit board. Sourcing inspected printed circuit boards will help you manufacture the best quality products that will meet your business standards. Sierra Assembly Technology is the best choice if you are looking to partner with a trusted and experienced PCB provider who can offer you well-tested printed circuit boards as well as PCB assembly services. Sierra Assembly Technology offers high-quality printed circuit boards that go through different inspections performed by experts. In addition to this, they also provide new product introduction (NPI) and supply chain management services. Get in touch with the experts at the company to know more.