Directed Energy Deposition Laser Head Integrated Design And 3D Printing Manufacturing

Directed Energy Deposition Technology,as an emerging surface modification technology,can realize the direct forming of large parts.And the coaxial powder feeding nozzle is one of the important parts of the directed energy deposition device.At present,there is no relevant design process for the development and commercialization of the nozzle.At the same time,the traditional machining method can no longer meet the needs of rapid manufacturing and people need to use SLM technology for rapid manufacturing of nozzles because of the complicated nozzle structure.This article explores key structural parameters of DED nozzles,summarizes design method and standardizes its SLM forming process and post-processing steps.Furthermore,it develops a set of quick-install cladding devices and its nozzles to verify the feasibility of the above research result.The main research results are as follows:1.Explore the design method of the key structure of coaxial powder feeding nozzle.For the powder channel structure,simulation software and fluid mechanics theory are used to analyze the movement law of the carrier gas powder,and a buffer structure is added to improve the powder convergence effect.Among them,the length of the powder channel buffer structure of the hole coaxial powder feeding nozzle is 15 mm and the pore diameter is 1.8mm;the length of the powder channel buffer structure of the annular nozzle is 15mm;For the cooling structure,combined with the design experience of conformal cooling channels,the structure to cool the heated area of nozzle is designed;For gas protection structure,considering with the gas flow rules and functional requirements,a compact gas channel is designed;2.Summarized the process for SLM forming and post-processing of coaxial powder feeding nozzle.Due to the limitation of the processing error of the SLM equipment and SLM principle,it is necessary to optimize the overhanging structure of the nozzle parts and determine suitable processing parameters.316 L stainless steel powder is used for processing.The specific parameters are follows: layer thickness 0.03 mm,laser power 160 W in the filling area,scanning speed 900 mm / s,edge scanning speed 400 mm / s,edge laser power 165 W,and remelting the the edge of the single layer twice.After the processing is completed,the key dimensions,inner hole roughness,and appearance of the nozzle parts are processed according to the postprocessing steps,and the performance is checked.3.Design a set of quick-install cladding device and its nozzle.According to the existing design methods and manufacturing processes,combined with the use requirements of directed energy deposition additive and subtractiove composite manufacturing equipment,a set of directional energy depositon device which can be used to switch with traditional cutting tools is developed.A coaxial powder feeding nozzle is designed and manufactured,and the rationality and repeatability of the design method and manufacturing process are tested.Finally,the equipment's work flow and programming method are introduced,and the simple directed energy deposition process is realized.