Study On The Control System Of Q-300A Metallographic Sample Cutting Machine Based On IPC-PLC

The Metallographic Sample Cutting Machine which is widely used in the machinemanufacture profession is mainly used to cut the metallographic sample. But at present, thecutting scope of domestic Metallographic Sample Cutting Machine is small and theautomaticity is low. It cannot directly carry on the sample to the big components. Althoughthe overseas Metallographic Sample Cutting Machine's performance is good and cuttingscope is broad, but the price is extremely expensive. In order to meet the professional needand promote our metallography enterprise development, researching on the large-scaleMetallographic Sample Cutting Machine is imperative. After earnestly realizing theprinciple of the metallography cutting technology and the special request of the cuttingmetallographic sample, the Q-300A Metallographic Sample Cutting Machine controlsystem is researched and designed.According to the mechanism and the work principle of large-scale MetallographicSample Cutting Machine, the control system has been designed with the thought ofmechanical and electrical integration. The heart of the control system is ProgrammableLogic Controller (PLC). Industrial Personal Computer (IPC) works as the input and thedemonstration module. IPC is also called Host Computer, which provides aperson-machine intercommunication interface and carries on the monitoring and themanagement about entire system. PLC is also called Slave Computer, which executes areliable effectively control on the spot. OMRON Host Link unit and the serial line are usedin the 1:1 interconnection system of IPC and PLC. The MSComm connection module ofVisual Basic 6.0 is applied to the reliable serial port data communication.Frequency conversion timing technology is adopted to control the three postureasynchronism motor to attain stepless timing for adapting to request of cutting differentmaterials. The mate speed of the grinding wheel carries on real-time sample through thephotoelectric sensor which utilizes the functions of high speed count of PLC and PIDcontrol of analogue variable. As a result, the PID closed loop control of the velocity of thegrinding wheel comes true, the control precision of the velocity is improved, the flexibilityof cutting different materials is boosted up and the sample quality is guaranteed. Thecontrol of three step motors has come true by PLC through three step motor drivers. Xdirection step motor and Y direction step motor can make the working platform movesmoothly according to the front or rear and the right or left of setting speed. Z direction step motor is utilized to move grinding wheel, the speed can be set according to sizes of thecut sample. PLC controls one transducer and three step motor drivers so that the worktable,the cantilever and grinding wheel can move in phase and the task of cutting is completed.The control system of the cutting machine has been designed in two kinds of control way:automatic operation and manual operation. The automatic operation has four kinds ofcutting modes: cut off workpiece once, cut off workpiece with advancing three steps andretreating one step, cut off workpiece layer by layer, cut off workpiece in series. Thecutting ability of the cutting machine was enhanced, so that cutting machine can cut offvarious sizes of parts efficiently. VB6.0 development platform is utilized to design IPCdisplay and input interface which provides the system with a simple, practical, safe andreliable person-machine intercommunication interface. In addition, the control system hasadopted the electrical equipment protection and the electric circuit antijamming measure sothat its security and reliability have been enhanced. Massive cutting experiments have beencarded out after finishing the installing and debugging of system. The practice proves thatthe Metallographic Sample Cutting Machine can achieve the desired result.The control system of Metallographic Sample Cutting Machine has a novel designand a reliable function. Its cutting scope is expanded (maximum curing diameter isΦ160mm, maximum cutting width is 300mm). It realizes the cutting automation, reducesthe labour and enhances the work efficiency, so it has good values of practicality andspread.