Visual Quality Inspection

Visual inspection is a critical part of PCB assembly quality control. It ensures assembled boards are free from defects and helps manufacturers catch design and manufacturing flaws early on.  

PCB visual inspection can be done manually, using microscopes and magnifying tools, or automatically with AOI equipment. AOI systems use digital cameras to scan PCBs, which helps identify defects that may be difficult to spot with the naked eye.

To ensure quality, Venture adopts both manual and automated PCB inspection methods. These are performed at different stages of the PCB manufacturing process. During inspection,QA inspectors authenticate boards based on these specifications.

• The quality of PCB surface
• Board thickness correctness
• Dimensional accuracy
• The integrity and clarity of conductive features
• Coating quality
• Via placement and pad plating quality

Manual Visual Inspection of PCB

The manual visual inspection of PCB assembly is simple, quick, and inexpensive. It can also be performed at virtually any stage. This is the most preferred inspection method for simpler boards or low-production runs and prototypes.

Using digital microscopes, quality control inspectors examine individual boards. The PCB inspection microscope has a tilting table. This allows for greater control of the process.

PCBAs are compared to a “Golden Board” or a detailed inspection list to pick out any defects. The Golden Board is an approved PCB that has all the required features. It acts as the blueprint against which other PCBAs are matched.

AOI PCB Inspection

AOI, or automated visual inspection of PCB assembly, helps identify defects that may be difficult to spot using the manual process. This method is often used when smaller and high-density PCBAs are being checked, or if production runs are high.

Using an automated PCB visual inspection machine, operators check for defects in the assembled boards. This involves the use of digital still and video cameras to scan the PCB. The captured image is then compared against an approved board or design data and specifications checklist.

Venture also uses both 2D and 3D PCB visual inspection tools for AOI. This serves to ensure a more detailed overview of the board features and their correctness, which is a crucial step when it comes to ensuring your PCBA is without defects.

PCB Assembly Visual Inspection Checklist

To conduct a thorough PCB inspection procedure, visual inspectors use a detailed inspection checklist. The checklist contains all the features that boards are to be checked for. At venture, PCB assemblies are checked for the following.

Component Check

All required components must be assembled and correctly placed in their positions. PCB quality inspection at Venture is aimed at verifying the following component specifications:

• Component defects
• Misplaced components
• Misaligned components
• Damaged components
• Missing components
• Reversed component polarity
• Incorrect component value

Coating Check

PCB visual inspection procedure at Venture includes examining the coating for errors that may have resulted from manufacturing errors. The board is checked for these defects:

• Thickness
• Uneven spread
• Tears
• Pin pricks
• Masking correctness

Soldering Check

Venture uses a comprehensive PCB inspection checklist for the solder joints. This ensures your PCBs have been correctly soldered. During the inspection process, boards are checked for these defects.

• Soldering shorts or bridges
• Voids
• Bumps
• Open circuits
• Excess solder
• Too little solder
• Soldering quality

Verified boards are then passed on to the next stage of the PCB manufacturing process. This can be any phase, from the fabrication stage to the point where the board is populated with components.

At Venture, we understand what it means to have your PCB assembly perform as expected. By implementing various visual PCB inspection methods, we ensure your product is high quality and without defects. For more about our PCB manufacturing and assembly services, contact us today!