Evaluation of AOI equipment, AOI testing equipment, and AOI testing instrument
The full name of AOI is Automated optical inspection, which is based on optical principles to detect common defects encountered in welding production. It is mainly used in SMT production line to detect the quality of soldering joints of components mounted on circuit boards.
The core of AOI equipment is its image acquisition and image recognition system, which can identify and judge whether components or solder joints have errors or abnormalities by collecting, processing and analyzing the images of components, solder joints and pins. AOI equipment can be used to detect common component missing components, component wrong components, wrong orientation, posture errors, position errors, solder joints, solder shortages, excessive solder, and false soldering and empty soldering errors that are common in the circuit board production process. . Compared with manual detection, automatic optical detection technology has the characteristics of fast detection speed, high detection accuracy, and good detection repeatability. The use of AOI equipment can quickly detect and feedback component placement or solder joint errors in the circuit board production process, shorten the commissioning time of the new board, reduce the rejection rate, and provide real-time feedback, diagnosis, and troubleshooting of various faults on the production line. Abnormal, at the same time can greatly reduce the labor cost of the production line. In the highly competitive circuit board production industry, A0I technology is becoming an effective tool for circuit board manufacturers to improve product quality, reduce production costs and increase production efficiency.
2. Application of AOI equipment:
AOI equipment is usually divided into two types: online and desktop (offline). The online AOI detector can be placed after the solder paste machine to check the quality of the solder paste printing, after the placement machine to check the quality of the components, and after the reflow oven to check the quality of the solder joints. Desktop AOI detectors need to manually transfer the circuit board to the detector. Desktop AOI testers are generally only used to test circuit boards with solder joints.
AOI can be placed in different positions after printing, before welding, and after welding.
1. AOI is placed after printing-it can check the printing quality of the solder paste. It can detect the amount of solder paste is too much or too little, the position of the solder paste pattern is offset, and there is no adhesion between the solder paste patterns.
2. AOI is placed after the placement machine and before soldering-it can check the quality of the patch, it can detect the wrong component, component displacement, component reverse (such as resistance flip), component side stand, component loss, extreme Sexual errors, and excessive mounting pressure causes adhesion between solder paste patterns, etc.
3. A0l is placed behind the flow soldering furnace-it can be used for welding quality inspection, which can detect wrong component placement, component displacement, component reverse (such as resistance flipping), component loss, wrong polarity, solder joint wettability, soldering tin Excessive amount, too little amount of solder, missing solder, false solder, bridge, solder ball (soldering ball between pins), component lift (tombstone or tombstone) and other soldering defects.
It is the most common practice to inspect the circuit board after placing the AOI in the reflow furnace, because the quality of the entire line can be controlled at this time, and of course the efficiency is the highest.
3. Operation process of AOI testing equipment
The operation process of AOI testing equipment is mainly divided into western parts: learning process and testing process. In the learning process, the AOI control software needs to learn and collect the code, position, code, polarity and other properties of the standard components on the standard circuit board and the standard image, and form a test program to save; in the test process, AOI The control software collects the image of the circuit board to be inspected, and uses the inspection process generated in the learning process to perform image recognition on each component and solder joint, and finally records and reports the recognition result to the operator.
The inspection of the circuit board requires at least one learning process to generate the inspection program, and then each circuit board is inspected accordingly. Of course, because in the production of circuit boards, there may be situations such as holding materials, so the inspection program needs to be adjusted during the inspection process to ensure the smooth progress of the inspection.