Fundamental Research On Building Process Of Inclined Thin-walled Parts On Laser Deposition

As a typical part,thin-walled parts have the advantage of small size,light weight,compact structure,saving materials,strong bearing capacity,is widely used in aerospace,ships,automobiles,molds and other industrial fields.Using the traditional processing method to process thin-walled parts,there are some defects such as large metal cutting volume,easy deformation,complex structure of mold and auxiliary manufacturing.Laser cladding deposition technology is a kind of advanced manufacturing technology combined with laser cladding surface modification technology and additive manufacturing thought,and it can rapidly manufacture fully dense functional metal parts with no mold and auxiliary.The use of laser cladding deposition technology to manufacture thin-walled parts has the advantages of short time period,material saving and excellent mechanical properties.In this paper,the laser,powder and velocity which are the fundamental process parameters in the process of laser cladding deposition are studied by using HWF20 laser cladding 3D Printing and remanufacturing system.The stability of the feeding powder was studied by using the way of weight collection by electronic balance.The speed of the deposition head is measured by using high speed camera combined with the way of machine vision,and the limit corner of the deposition head deceleration is obtained.The change in height of the deposition head will change the convergence point of the powder,thus affecting the cladding height.The temperature directly below the melting pool under different deposition head height is measured by infrared Thermal Imager.Based on the results of the study of the basic process parameters,a process method is proposed to improve the deposition defects of the high starting point and the tail collapse of the straight thin-walled parts,and the high inflection points of the thin wall parts with sharp.The deposition efficiency of straight thin-walled parts is studied.The powder feeding rate is the main parameter affecting the deposition efficiency.The deposition method,the tilt angle error,the width and height of thin-walled parts are studied.The angle,height and width of the deposited oblique thin-walled parts are measured by microscope.In this research,the angle error of deposited oblique thin-walled parts by deposition head offset method is large,the change attitude method of deposition head and the tilt method of substrate is small,and with the increase of tilt angle,the height of thin-walled parts becomes lower and the width of the inclined thin-walled parts is basically unchanged.The temperature field of thin-walled parts under different cooling conditions is simulated numerically,and the variation law of temperature field and the residence time of molten pool in the deposition process of thin-walled parts are obtained.The Powder flow field formed by thin-walled parts under different deposition head height and three kinds of powders in the form of oblique thin-walled parts are numerically simulated,and the corresponding distribution law of powder concentration is obtained.