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In this application the operator supplies the machine with raw parts at entry end of the cell and finished parts are removed by a robotic arm at the other end. The cell runs essentially unattended. It makes use of Closed Loop Control, which essentially is a method of making near perfect parts. It does this by automatically positioning a tool on a machine such that each feature on a part will be machined to the nominal value for that feature.
This application calls for monitoring 5 features (characteristics). Three of these features make use of Closed Loop Control. FSWorks is connected to a Fanuc18i machine controller via ethernet. FSWorks does the gauging for the application. Each time a part is made, FSWorks measures the five features in question. If any of these features are out of tolerance, FSWorks sends a message to the machine controller and the part is put in a reject bin. In addition, three of these features have the measurement values monitored a little more closely. The average for the last three parts for each of these three features are held in memory. As long as these averages fall within the control tolerance ban set for these features there will be no offsets sent to the machine controller. On the other hand if one these averages does not fall within the control tolerance ban, an offset will be sent to the machine controller in an amount that is equal to the difference between this average and the nominal value for this feature.
For example, one of the features being controlled is height. The nominal value for height is 12.5 mm. The tolerance for height is 12.45 to 12.55 mm. The control tolerance is 12.475 to 12.525 mm. If the average for the last three parts is 12.539mm an offset of (12.539mm - 12.5mm) or -.039mm will be sent to the machine controller and the value of the height for the next part should be 12.5mm.
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