Pre-reflow AOI : An Effective Tool for Improving Product Yield
Overview
The pre-reflow AOI is a technology that uses automatic optical inspection to inspect printed circuit boards prior to reflowing in
the SMT assembly.
Pre-reflow AOI is a pre-reflow inspection that uses optical processing to analyze the image and
determine if there are any defects, such as wrong parts, missing, offset or reversed, etc.
Principle
1) Image Processing
The core technology for pre-furnace AOI is optical image processing. This technology can convert an
image from a circuit board to a digital image, and then analyze that digital image.
The main optical image processing technologies that are used in pre-reflow AOI include:
• Image matching technology: The circuit board image is compared to a standard image in
order to determine if there are any defects.
• Image Analysis Technology: By analysing the image of a circuit board and identifying
its location, shape and size, as well as judging if there are defects.
• Image Feature Recognition Technology: Identify whether or not there are defects in
the circuitboard image by identifying features.
2) Software Analysis
The software analysis component is also a significant part of the pre-furnace A.O.I. It is responsible
for analysing the image and determining if there are any defects.
The main features of the software analysis system that is used by the furnace AOI are:
• High Precision: Can accurately identify defects.
• High Speed: Images can be processed quickly.
• Scalability: can be expanded to meet the needs of various products.
Test Items
The following defects can be detected by AOI prior to the furnace:
• Missing Components: components missing from circuit board.
• Offset: Mounting components SMT in the wrong position.
• Reverse: The direction of component soldering is incorrect.
• The wrong parts: The circuit board is populated with the incorrect components.
Application
Tablet computers are essential tools to work, entertain and for entertainment, and their quality
standards are high. The AOI pre-reflow can detect and correct any problems quickly.
Modern information systems are not complete without servers. Circuit boards are complex and pre-furnace
optical inspection can identify and correct any problems quickly.
The components of medical equipment are a vital part of ensuring the health and safety for the people.
They require a high level precision.
Pre-furnace AOI is able to detect and correct any problems that may occur during the manufacturing of
medical devices. This ensures the safety and reliability.
Pre-furnace AOI is required to detect and fix problems in time. Aerospace equipment must meet very high
standards of quality.
Benefits
Reduced PCB rework cost: The pre-furnace AOI detects problems like missing parts,
misalignment and reverse polarity. This reduces the circuit rework time and costs.
Reduced scrap costs: The AOI pre-furnace can detect defects that are not repairable,
thus reducing scrap prices.
Improved production efficiency: Furnace front AOI helps PCB makers identify and correct issues,
improving production efficiency.
Conclusion
The pre-furnace inspection is done before the parts are mounted. This can reduce the PCB rework and
scrap costs.
Increase production efficiency to increase product yields and reduce production costs.
Pre-furnace AOI has a wide range of applications and is an essential detection method for PCB assembly.
