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1、过程品质控制通往零缺陷制造的途径（Process quality control the approach to zero defect manufacturing）Process quality control: the approach to zero defect manufacturingProcess quality control: the approach to zero defect manufacturingThe ultimate goal of adopting AOI will determine where to place the AOI on the produc
2、tion line and what process control information will be produced.As printed circuit assembly becomes smaller and more dense, automatic AOI (automated optical inspection) devices are increasingly used to monitor and guarantee the quality of board (PCB, printed, circuit). In addition, the efficient use
3、 of AOI with specialized purposes can produce process control information of different types and levels of detail.There are four types of targets for implementing AOI inspections:1. final quality (End, quality). Manufacturers who focus their attention on the final quality are interested in the statu
4、s of the product when they leave the production line. This goal is preferred when production issues are clear, product mix is high, and quantity and speed are critical factors. AOI will usually be attached to the end of the line. In this position, the device can produce a wide range of process contr
5、ol information.2. process tracking (Process tracking) uses inspection equipment to monitor the production process. Typically, detailed defect classification and element placement offset information are included. This is a priority for manufacturers when product reliability is important, high-volume
6、manufacturing is low, and supply of components is stable. This often requires moving the inspection equipment to several locations and monitoring specific performance online. Process control information is usually less than the final quality goal, but it can directly find specific process problems.
7、Support the steps of special process process control information may be more quantifiable than the other target.3., ICT (ICT, test, in-circuit), pass through rate (FPY, first-pass, yields), reaction process capabilities and any difficulties in the steps. The AOI device improves the pass rate of the
8、ICT by finding the defect plate and sending the defect plate to repair before the first ICT. When production volumes are large and demand times are short, manufacturers are given priority in order to make testing and delivery of products a critical issue. Because AOI is placed near the final end of
9、the line, process control information is typically qualitative.4. characterization (Characterization). In the production of hazardous assemblies, i.e. medical or military applications, the inspection equipment must be adjusted to find all possible abnormalities. As a result, there is almost no omiss
10、ion rate, but it produces false positives and requires longer inspection times. AOI is typically used at the end of the production line to check solder points, but it can be removed to monitor the special process. The key production factors for this goal are the type of production, the risk of site
11、failure, and the allowable monitoring time. Qualitative and quantitative process control information can be generated, depending on the location and setting of the equipment.In many applications, the AOI machine settings will be no different for any of these goals. The difference is to check how the
12、 machine is used. For example, check the machine typically only signs of serious defects, however, if the feature as the inspection target, the user may browse to the (or to check the equipment abnormal report) just enough serious, not enough to fully reflect the characteristics of the product. The
13、inspection facility must support all of these inspection targets and move from one to the other. Similarly, process control information may vary depending on the use of the device. For example, although component mount information can be collected and checked by reflow soldering, the use of this inf
14、ormation will be checked before reflow soldering. At this site, defects associated with mounting machine errors may be less relevant.Implementation strategy (Implementation, Strategies)The location placed by the machine can realize or hinder the inspection target, and different positions can produce
15、 different process control information. The placement of AOI is determined by the following factors:1. special production problems. If the production line has specific problems, the inspection equipment can be added or moved to this location to monitor defects and detect duplicate problems as early
16、as possible.2. implementation objectives. For inspection equipment, there is no best place to handle all production line defects (Table 1). If the goal of implementing AOI is to improve the overall final quality, placing the machine in front of the process may not be worth much later. One argument that the machine puts in front is to avoid adding value to the products that are already defective. Also, the cost of maintenance in the early stag
