Modeling of flow and debris ejection in blasting erosion arc machining in end milling mode

Blasting erosion arc machining(BEAM)is a typical arc discharge machining technology that was developed around 2012 to improve the machinability of difficult-to-cut materials.End milling BEAM has been successfully developed and preliminarily applied in industry.However,owing to the high complexity of the flow field and the difficulty of observing debris in the discharge gap,studies of the flow and debris in end milling BEAM are limited.In this study,fluid dynamics simulations and particle tracking are used to investigate the flow characteristics and debris ejection processes in end milling BEAM.Firstly,the end milling BEAM m o d e is introduced.Then the numerical modeling parameters,geometric models,and simulation methods are presented in detail.Next,the flow distribution and debris ejection are described,analyzed,and discussed.The velocity and pressure distributions of the axial feed and radial feed are observed;the rotation speed and milling depth are found to have almost no effect on the flow velocity magnitude.Further,debris is ejected more rapidly in the radial feed than in the axial feed.The particle kinetic energy tends to increase with increasing milling depth,and smaller particles are more easily expelled from the flushing gap.This study attempts to reveal the flow field properties and debris ejection mechanism of end milling BEAM,which will be helpful in gaining a better understanding of BEAM.

An automatic arc welding machine for saddle joint seams on large diameter cylinders

This paper deals with the structure, components, characteristics and work principle of a newly developed automatic arc welding machine for saddle joint seams on large diameter cylinders. The equations for designing the geometry and dimensions of the cam controlling the moving locus of the welding torch have been derived. This welding machine has successfully been used in automatic welding saddle joint seams on boiler drums with good results and low cost.

Electrical arc contour cutting based on a compound arc breaking mechanism

Electrical arc contour cutting(EACC)is a novel high-efficiency material cutting process that applies arc plasma to perform efficient and economical contour cutting of difficult-to-cut materials.Compared to conventional electrical arc machining(EAM),this process can remove the allowance of open structures and plates in bulk mode,rather than entirely in the form of debris.Compared with existing contour cutting methods,EACC possesses the advantages of high cutting efficiency and a deep cutting depth.Particularly,a compound arc breaking mechanism(CABM),which integrates hydrodynamic force and mechanical motion,has been applied to control the discharge arc column in EACC,while also strengthening the debris expelling effect in the narrow discharge gap.The CABM implementation conditions were studied,based on arc column distortion images captured by a high-speed camera and simulation results of the flow field and debris distribution.A set of machining experiments was designed and conducted to optimize the performance of the proposed process.Finally,a SiC_(p)/Al metal matrix composite(MMC)space station workpiece was machined to verify the feasibility and efficiency of this process.