Research On The Precision Of Thin-walled Cylindrical Parts Based On Hybrid Additive And Subtractive Manufacturing

The hybrid additive and subtractive manufacturing technology gives full play to the advantages of laser additive manufacturing technology,such as convenience,high flexibility,as well as the advantages of high-quality machining accuracy of subtractive processing,and is favored by more and more universities and research institutions.In this paper,the dimensional accuracy and shape accuracy of thin-walled cylindrical parts made by hybrid additive and subtractive processes were studied.Firstly,based on the analysis of the structural characteristics of thin-walled cylindrical parts,the experimental research method was set.By comparing and analyzing the linear fitting and curve motion fitting,the curve motion fitting was finally selected,and the manual programming was used to plan the forming path of the additive parts.Based on the surface quality of the formed parts,the forming process parameters of the additive were set;and the subtractive processing parameters were set according to the cutting technology manual.In this paper,the coordinate data of the thin-walled parts were measured and recorded by the on-line measurement system in the machine.The on-line measurement system was used to measure and record the data of the wall coordinate points of the thin-walled parts,and the least square polynomial fitting method was used to fit the coordinate data points to obtain the inner and outer diameters,wall thicknesses,dimensional errors and shape errors of the thin-walled cylindrical parts.And the coordinate data points of the parts were fitted by the least square method to obtain the inner and outer diameter,wall thickness,dimension error and form error of the thin-walled cylindrical parts.Secondly,the dimensional accuracy,The shape accuracy and their time variation of the forming parts were studied,and the influencing factors of the forming accuracy were analyzed.The results show that it becomes more obvious that powder sticks on the wall with the increase of the height.The error of wall thickness is positive,and the error decreases with the increase of height.The roundness of the formed part keeps stable despite the change of the height,and the roundness of the outer wall was larger than that of the inner wall.The cylindricity of the outer ring was greater than that of the inner ring.After the additive manufacturing process,with the increase of time,the dimensional error of the formed part is reduced,and the change of the roundness error is basically stable.60 minutes after the end of the additive process finished,the dimensional error and the roundness error of the formed parts remain unchanged.Finally,the dimensional accuracy,the shape accuracy,and their time variation of subtractive processing based on additive manufacturing were explored,and the effect of additive manufacturing process on subtractive material processing accuracy was analyzed.The results show that after subtractive processing,the surface quality,the dimensional accuracy and the shape accuracy of the additive parts have been greatly improved.Differences in additive manufacturing,after subtractive processing,the cylindricity of the inner wall of the thin-walled columnar member is greater than the cylindricity of the outer wall.After the subtractive process was completed,with the increase of time,the variation range of the size error of each height is different,and the roundness error remains basically unchanged.By intervening in the subtractive processing before and after the stabilization of the additive parts,it is shown that the precision of the parts can be improved by cutting the material immediately at the end of the additive process.In this paper,by studying the forming precision of hybrid additive and subtractive manufacturing,the influence of additive manufacturing process on the processing accuracy of subtractive material was analyzed,and a method for improving and controlling the forming accuracy of laser additive manufacturing was proposed.The method of improving and controlling the processing accuracy of hybrid additive and subtractive manufacturing was proposed by using the time variation nature of part size error and shape error.It provides guidance for improving the processing precision control of the thin-walled cylindrical parts manufactured by hybrid additive and subtractive technology.