Study On The Structure Design And Additive Manufacturing Of Magnetically Controlled Oscillating Plasma Arc Sensor

Plasma arc material with fast deposition rate,high deposition rate,filling the advantages of the preparation of a morphology is not limited,on the rapid deposition into component has its huge development potential,but under the traditional method,the size of each metal deposition layer are fixed,and in the process of multi-channel manufacturing,material heat accumulation gradually increase,increasing surface uneven phenomenon,As a result,the morphology and quality of the prepared parts will deteriorate,and even affect their use.In this paper,for the existing plasma arc additive manufacturing process of low intelligence,morphology precision is not high,the difficulty of heat input control and other key points,the use of transverse magnetic field to control the plasma arc swing,the heat input in the additive process control,so as to improve the size and morphology of the prepared parts.By building a magnetic swinging plasma test platform and designing a special magnetic swinging plasma arc sensor,the simulation analysis and test verification of the excitation system are carried out.According to the additional process variables of arc additive in this paper,the exploration methods of single path,single channel and multi-channel are set up.The numerical coupling simulation of arc attitude was carried out by using COMSOL.It was found that when there was no magnetic field,the heat of the flame flow inside the arc was distributed in a "bell bell" shape from top to bottom,and the local heat of the flame arc flow decreased continuously from the tip to the substrate and gradually to the periphery.When the flame arc velocity escapes from the nozzle,the velocity will reach the peak.The arc pressure curve is shown as a parabola,and the pressure peak is located at the base material position below the nozzle axis.When the magnetic field is added,the heat of the internal flame arc flow deviates and the peak value of heat decreases slightly.The flame arc flow escape rate reaches its peak at the exit boundary,and the peak arc stiffiiess will occur with the deflection of the arc column.Simufact welding was used to conduct thermodynamic coupling simulation of additive manufacturing process to explore the evolution law of the melt layer.It was found that the arc starting point and arc ending point in the same melt layer experienced different thermal cycles,which resulted in the inhomogeneity of microstructure in the layer.There are also some differences in the thermal cycles of different alluvial layers,which result in the difference of the interlayer structure.Subsequent deposited material has certain stress relaxation effect on the metal material deposited previously.However,the stress relaxation effect is gradually reduced as the deposition process continues.As the deposition process increases,the depressions in the middle part of the additive occur and the bending deformation occurs at the end of the additive,while the deformation in other parts is not significant.The shape of magnetron oscillating plasma arc was filmed by high speed camera,and it was found that the shape of arc intercepted was close to that of simulation.At the same time,orthogonal test method is used to study the influence of process variables on the manufacturing of magnetically controlled oscillating plasma arc additive.The results show that the order of the influence of the layer height on the welding factors is wire feeding rate,magnetic field strength and welding current,while the welding rate has no significant effect on the layer height.The order of influence degree of welding width is welding rate,welding current,magnetic field strength and wire feeding rate.