A new method for suppressing cutting chatter is studied by adjusting servo parameters of the numerical control （NC） machine tool and controlling the limited cutting width. A model of the cutting system of the NC mac...A new method for suppressing cutting chatter is studied by adjusting servo parameters of the numerical control （NC） machine tool and controlling the limited cutting width. A model of the cutting system of the NC machine tool is established. It includes the mechanical system, the servo system and the cutting chatter system. Interactions between every two systems are shown in the model. The cutting system stability is simulated and relation curves between the limited cutting width and servo system parameters are described in the experiment. Simulation and experimental results show that there is a mapping relation between the limited cutting width and servo parameters of the NC machine tool, and the method is applicable and credible to suppress chatter.展开更多
This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test ...This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerr ratio of the bottom width to the top width can be determined. In addition, the analysis of ranges and variances are all employed to identify various factors： traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. ~rthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerr ratio. Finally, the verification experiments of cutting parameters＇ effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ.展开更多
The objective of this work was to investigate the possibility of taper angle correction in cutting of complex micro-mechanical contours using a TruMicro ultra-short pulse laser in combination with the SCANLAB precSYS ...The objective of this work was to investigate the possibility of taper angle correction in cutting of complex micro-mechanical contours using a TruMicro ultra-short pulse laser in combination with the SCANLAB precSYS micro machining sub system. In a first step, the influence of the process parameters on the kerftaper angle of metallic alloys was systematically investigated without beam inclination. A set of base parameters was derived for the subsequent investigations. In a second step, the kerftaper angle was controlled by static beam inclination. In a third step, the same optics was used in its dynamic precession mode to fabricate micro-mechanical components of complex contours with perpendicular 0~ taper angles. It was found that taper angle adjustments of up to 7.5~ are possible with the used setup for cutting applications. Taper angle control is possible both in the static beam inclination mode and in the dynamic precession mode. The static mode could be interesting for contours with sharp inner radii and for achieving faster cutting times similar to results with fixed optics, but would require excellent synchronization of beam inclination and axis motion. The dynamic precession mode would allow an easier integration of the optics into a laser machine but will result in longer cutting times and limitations with respect to achievable inner radii.展开更多
Experimentation data of perspex glass sheet cutting, using CO2 laser, with missing values were modelled with semi-supervised artificial neural networks. Factorial design of experiment was selected for the verification...Experimentation data of perspex glass sheet cutting, using CO2 laser, with missing values were modelled with semi-supervised artificial neural networks. Factorial design of experiment was selected for the verification of orthogonal array based model prediction. It shows improvement in modelling of edge quality and kerf width by applying semi-supervised learning algorithm, based on novel error assessment on simulations. The results are expected to depict better prediction on average by utilizing the systematic randomized techniques to initialize the neural network weights and increase the number of initialization. Missing values handling is difficult with statistical tools and supervised learning techniques; on the other hand, semi-supervised learning generates better results with the smallest datasets even with missing values.展开更多
Based on the LOM(Laminated Object Manufacturing)process,an inert gas-assisted laser method for wood cutting was proposed.The carbonization degree of wood surface was improved by the introduction of helium(He)gas,and t...Based on the LOM(Laminated Object Manufacturing)process,an inert gas-assisted laser method for wood cutting was proposed.The carbonization degree of wood surface was improved by the introduction of helium(He)gas,and the influence of process parameters on the carbonization layer of wood surface was solved,it was significance to reduce the post-processing of LOM and improve the quality of forming workpiece.The cherry wood veneer was used as the experimental material,under the condition of the same process parameters,the wood was cut with or without inert gas-assisted,and the influence factors of kerf quality were studied by variance analysis.The results showed that under the same condition,compared with traditional laser processing,the kerf width was obviously reduced in the inert gas-assisted cutting.Because the He gas had oxygen-isolation and flame retardant effect,which prevented heat accumulation and conduction.The micro morphology of the kerf surface showed that the flatness was better in the inert gas-assisted cutting.As the excess heat was blown out by the cooling and purging of the gas,the phenomenon of oxidation and burning was reduced,the range of HAZ(heat affected zone)was reduced,and the carbonization phenomenon was obviously improved.The surface quality of kerf was improved effectively.According to the analysis of variance,in addition to the effect of laser power,cutting speed and inert gas flow on the cutting width,the interaction between inert gas flow and laser power,laser power and cutting speed were also the main factors which affected the cutting width.The feasibility of the combined inert gas and laser processing to improve wood cutting quality has been verified through experimental research,which provided a certain reference for the followup research on improving the wood processing quality.展开更多
文摘A new method for suppressing cutting chatter is studied by adjusting servo parameters of the numerical control （NC） machine tool and controlling the limited cutting width. A model of the cutting system of the NC machine tool is established. It includes the mechanical system, the servo system and the cutting chatter system. Interactions between every two systems are shown in the model. The cutting system stability is simulated and relation curves between the limited cutting width and servo system parameters are described in the experiment. Simulation and experimental results show that there is a mapping relation between the limited cutting width and servo parameters of the NC machine tool, and the method is applicable and credible to suppress chatter.
基金supported by the Science and Technology Development Foundation of Shanghai Municipal Science and Technology Commission (Grant No.037252022)
文摘This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerr ratio of the bottom width to the top width can be determined. In addition, the analysis of ranges and variances are all employed to identify various factors： traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. ~rthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerr ratio. Finally, the verification experiments of cutting parameters＇ effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ.
文摘The objective of this work was to investigate the possibility of taper angle correction in cutting of complex micro-mechanical contours using a TruMicro ultra-short pulse laser in combination with the SCANLAB precSYS micro machining sub system. In a first step, the influence of the process parameters on the kerftaper angle of metallic alloys was systematically investigated without beam inclination. A set of base parameters was derived for the subsequent investigations. In a second step, the kerftaper angle was controlled by static beam inclination. In a third step, the same optics was used in its dynamic precession mode to fabricate micro-mechanical components of complex contours with perpendicular 0~ taper angles. It was found that taper angle adjustments of up to 7.5~ are possible with the used setup for cutting applications. Taper angle control is possible both in the static beam inclination mode and in the dynamic precession mode. The static mode could be interesting for contours with sharp inner radii and for achieving faster cutting times similar to results with fixed optics, but would require excellent synchronization of beam inclination and axis motion. The dynamic precession mode would allow an easier integration of the optics into a laser machine but will result in longer cutting times and limitations with respect to achievable inner radii.
文摘Experimentation data of perspex glass sheet cutting, using CO2 laser, with missing values were modelled with semi-supervised artificial neural networks. Factorial design of experiment was selected for the verification of orthogonal array based model prediction. It shows improvement in modelling of edge quality and kerf width by applying semi-supervised learning algorithm, based on novel error assessment on simulations. The results are expected to depict better prediction on average by utilizing the systematic randomized techniques to initialize the neural network weights and increase the number of initialization. Missing values handling is difficult with statistical tools and supervised learning techniques; on the other hand, semi-supervised learning generates better results with the smallest datasets even with missing values.
基金The research was supported by Significant special research and development project of Guangdong province(2020B020216001)Fundamental Research Funds for the Central Universities(2572018CG06).
文摘Based on the LOM(Laminated Object Manufacturing)process,an inert gas-assisted laser method for wood cutting was proposed.The carbonization degree of wood surface was improved by the introduction of helium(He)gas,and the influence of process parameters on the carbonization layer of wood surface was solved,it was significance to reduce the post-processing of LOM and improve the quality of forming workpiece.The cherry wood veneer was used as the experimental material,under the condition of the same process parameters,the wood was cut with or without inert gas-assisted,and the influence factors of kerf quality were studied by variance analysis.The results showed that under the same condition,compared with traditional laser processing,the kerf width was obviously reduced in the inert gas-assisted cutting.Because the He gas had oxygen-isolation and flame retardant effect,which prevented heat accumulation and conduction.The micro morphology of the kerf surface showed that the flatness was better in the inert gas-assisted cutting.As the excess heat was blown out by the cooling and purging of the gas,the phenomenon of oxidation and burning was reduced,the range of HAZ(heat affected zone)was reduced,and the carbonization phenomenon was obviously improved.The surface quality of kerf was improved effectively.According to the analysis of variance,in addition to the effect of laser power,cutting speed and inert gas flow on the cutting width,the interaction between inert gas flow and laser power,laser power and cutting speed were also the main factors which affected the cutting width.The feasibility of the combined inert gas and laser processing to improve wood cutting quality has been verified through experimental research,which provided a certain reference for the followup research on improving the wood processing quality.
