| As an advanced precision machining technology, Double-sided grinding machine has been getting more and more attentions from economic developed countries. How to efficiently obtain a good roughness, flatness and flexion on optical material surface has become an important research direction of ultra-precision grinding technology. The pressure pneumatic loading precision, stability of the operation of upper and lower plate, and high precision of measuring apparatus are the main factors which affect the performance of grinding equipment.The theme of this paper is double-sided grinding control system. The use of advanced computer-aided design technology, advanced monitoring technology, pressure control technology, process control technology and user-friendly HMI enables unskilled operators reach a high level of precision machining. Abandoning PLC master controller which is used by many manufacturers, and using the IPC as main controller can increase the extendibility of the equipment and reduce cost as much as possible. Using IPC to fulfill the parameter setup of double-sided grinding process, production process management, monitoring and control, which can facilitate the later factory network and device management, equipment maintenance to achieve full monitoring of plant equipment. Using VB. NET software platform and MS-SQL database to achieve graphic interface functional parameter, high-precision height sensors, air-pressure sensors, digital proportional valve to form a combined control system to realize automatic processing and control of the aircraft. The main contents are as follows.1. Research on control system of industrial computer software, write control software and user interface by Visual Basic.NET. 2. Research on sized grinding and time-fixed grinding control mode, design and use high-precision altimeter(resolution 0.52μm, precision 2μm) to real-time monitor the workpiece size of grinding, so as to ensure the dimensional accuracy of the workpiece. 3. Research and algorithm on planet motion control make the workpiece motion trail variable in grinding process. The workpiece is placed in the loose pulley, which will be a planetary gear in the differential gear train composed by sun gear and ring gear. This makes the workpiece do planetary motion in contrast to the millstone in the process of grinding.4 Research on pneumatic pressure control. Test the lower cylinder pressure when installing high-precision air pressure sensor in the lower cylinder, and then feedback the pressure signal to the software control system to form closed-loop control. This ensures that the workpiece pressure can be accurately controlled and the pressure stability can be guaranteed. In addition, there are machine mortar hydraulic control, drainage control, trim control and other automatic control systems.After commissioning of the equipment, it is proved that the overall conditions of the equipment control system is good, the operation is stable, the subsystems work smoothly. Test the processing quality, processing efficiency, processing precision and processing cost of double-sided grinding machine processing sapphire material by experiment and customers’ long-term use. The precision of the double-sided grinding machine designed by this paper has reached the same level with overseas advanced machine tool, and the efficiency is even better than that of the Japanese equipment. |
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