| Nowadays in China the globalization of industrial division is deepening,labor cost is also rising and the market competition pressure becomes more and more intense.Small and medium-sized agricultural machinery enterprises in northern Jiangsu are anxious to automate the transformation of the existing strip shearing machines reduce labor cost,improve product quality and safety performance of shearing lines,and ultimately achieve the purpose of improving efficiency.The strip shear machine of JEEGEE Agricultural Co.,Ltd.has many problems,such as over-staff operation for a single machine,high labor intensity,low efficiency,high labor cost,potential safety hazards and sheet metal quality problems.In view of the above problems,we have improved the automation and designed the automatic control system of strip shear machine based on PLC.Based on universal punch press,the system uses servo motor to control speed synchronization of the front and back rollers to control the shearing accuracy.To realize the automation,specified modules are added to the production line,such as strip width limit,roller drive and transmission,material dividing device,photoelectric sensor(to detect the position of strip),PLC control mechanism and so on.The system can reduce investment while meeting production needs and is suitable for small and micro enterprises.This paper introduces the design process of the automatic control system for transverse shear of strip based on punch press.The servo drive system of high accuracy,low cost,small volume and easy control is selected for the automatic control scheme.In terms of system structure,the mechanical transmission scheme is determined after analyzing the characteristics of chain drive,belt drive and gear drive,real site condition and efficiency requirements.We use S7-200 series PLC as the controller according to the performance requirements.The closed-loop servo system is used in the drive system design,and the servo driver and servo motor of Delta are applied to control the speed.The shear length accuracy of sheet metal is the key parameter of fixed-length shearing.For better accuracy,we carry out the simulation analysis of fuzzy-PID control,design and debugging of the system software.After site installation,debugging and industrial test,PLC servo drive system is proved good performance on synchronous speed control,cutting head control,automatic length control,automatic positioning control and classification control of finished products and wastes. |
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