| In the laser cladding forming,the wire feeding cladding has the advantages of high efficiency,low cost,no hysteresis,excellent performance of the molded part,but the wire is rigid,the wire feeding speed is unstable,the wire feeding speed is unstable,and there are problems such as wire jump and burning nozzle in wire feeding.In order to improve the wire feeding stability,this paper specially designed a wire feeder driven by servo motor based on the three-beam optical inner wire nozzle,and integrated with the optical inner nozzle to control the wire feeding speed to be constant;The wire feeding nozzle improves the optical path structure inside the nozzle and improves the stability of the cladding;the feedback closed-loop control system which can correct the process parameters in real time is developed,and the actual layer height and expectation are adjusted through the speed proportional-integral(PI)digital controller.The error between the layer heights greatly improves the stability and accuracy of the wire cladding forming.According to the research requirements of three-beam optical internal wire forming process and process control,this paper constructs a three-beam optical internal wire feeding system,which mainly includes IPG fiber laser,wire feeding system,optical internal wire feeding nozzle,KUKA driving mechanism,work Platform,protection system and CCD imaging measurement system.The forming test uses a closed loop control system with PI feedback adjustment.The effects of process parameters such as laser power,defocusing amount,wire feeding speed and scanning speed on the morphology of the three-beam light feed wire are studied.The results show that the laser power and defocusing have the most obvious influence on the width and height of the cladding.A good negative defocus should be selected before the cladding.The influence of the change of process parameters on the laser cladding is mutual.Finally,a set of optimized process parameters were obtained by orthogonal test,and the cladding forming test was carried out.For the instability of the optical feed wire and the wire feeder can not achieve real-time feedback and other issues,this paper proposes a set of wire feeder and laser coating device based on Panasonic PLC.Through the PLC to realize the conversion of the voltage signal to the pulse signal of the servo motor,the closed-loop feedback control of the wire feeder is realized,and the stability and accuracy of the wire transmission are improved.Based on the CCD layer height measurement system,the optical internal wire is set to defocus.Closed loop forming technology and speed PI feedback control model.During the cladding process,the scanning speed of each layer is adjusted in real time,and the height of each layer of the melt is changed,so that the actual cladding height is approached to the desired layer height of the design,effectively solving the existence of the three-beam in-line wire feeding process.Unstable problems such as collapse,wire jump,and dripping.The formed thin-walled structural parts were designed.The structural model of thin-walled ring and straight-walled structural parts was proposed.The path planning and programming of the formed parts were carried out.The proportional digital link of the speed PI feedback control model was established as-10/s.The integral number link is-0.35/s,and the forming process converges quickly.During the forming process,the actual cladding height is close to the desired layer height,fluctuating in a small range around the desired layer height,and the stability is good,reaching the experimental design goal,and the speed PI controller has good control performance.The dimensional error analysis,hardness performance analysis and microstructure analysis of the thin-walled ring forming parts were carried out.The microstructure of the micro-grain was uniform and compact,the microstructure was well distributed,the microhardness value was evenly distributed,and the mechanical properties were good. |
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