The Research And Design For Band Sawing Machine’s Hydraulic System

As metal band sawing machine plays a more important role in the field of the processing of metal,people hopes that it has a better quality.First,machining efficiency should be improved.It should cut off a block of metal as soon as possible.Second,the cutting area on the metal should have a small surface roughness.Because if the roughness is small enough,the metal can be used without any other processing operation.Both of the two problems have a close relationship to the feed rate of the band sawing machine.Third,different kind of material has its own best sawing rate.And it is difficult for the band sawing machine that is sold on the market to change its sawing rate.The band sawing machine that produces by the company of China can merely change its feeding rate.And the changing of sawing rate mostly depends on belt pulley.This kind of phenomenon indicates that the digitalization of such kind of band sawing machine is very low.This paper focuses on these problems and do research on speed control.Firstly,this paper depends on the mechanical transmission and hydraulic transmission principle of the band sawing machine putting forward the method of speed control.To be specific,PLC and inverter are used to change the speed of engine.And then sawing rate is changed.The changing of feed rate depends on the using of electro-hydraulic proportional valve,amplifier of proportional valve and speed sensor.Secondly,since it is a mature technology to use inverter changing the speed of sawing rate,this paper focuses on the changing of feeding rate.And the paper consists of three parts.(1)The mathematical model of all hydraulic components is built,so that transfer function can be got.MATLAB/Simulink is used to analyze the performance of the hydraulic system by simulation.Then,a special hydraulic simulation software that is named AMESim is used to analyze the performance of the hydraulic system.By contrast with the result that getting from the software of MATLAB/Simulink,we can draw the conclusion that mathematical model is reliable.(2)Basing on the mathematical model,PID is used to optimize the performance of the hydraulic system.Trial-and-error method is used to do the tuning PID parameters.(3)Since the key parameters of hydraulic system are changing when band sawing machine is processing,PID parameters should be changed to adapt to the new working condition.This paper uses the method relay feedback to do the tuning PID parameters,so that the system is working very well.And this kind of method can be easily combined with the modern computer to realize the digitalization of band sawing machine.