| With the increasingly widespread application of hard and brittle material,the cutting process technology requirements are also getting higher and higher.Hard brittle materials with high hardness and brittleness,the machining process is very difficult.At present,the diamond wire saw process because of the narrow kerf,high flexibility and low material waste rate and become brittle material processing of choice.However,the reciprocating saw cutting of brittle materials,due to the frequent change direction of wire saw movement,cause workpiece surface scratch and low effective utilization of wire,and wire speed cannot go fast.In order to solve the above problem,this paper proposes endless electroplated diamond wire saw to improve the cutting speed and reduces the wafer surface roughness,which provides the theoretical analysis and experimental research for the cutting process of hard and brittle materials.Compared with the traditional reciprocating wire saw,looped Diamond wire saw is a single movement way,without reversing the mechanical inertia effect,which can realize high speed sawing.This study investigates the 0.25 mm wire saw fixed diamond abrasive welding by Capacitor Discharge Percussion Welding(CDPW),and analyzes the process parameters affecting physical and mechanical performance of joint in welding process,the Central Composite Design(CCD)is used to design experiment scheme to study the impact of the welding capacitor,welding voltage and heat treatment temperature on welding performance.An empirical model has been developed for analysis welding break tension of looped diamond wire saw and Response Surface Methodology(RSM),analysis of variance and function of satisfaction(DFM)are used to determine the optimal process parameters for the maximum break tension of wire saw joint,the validated tests show that the model can predict the break tension for different process parameters.Through observation of the microstructure and mechanical properties testing of welded joints,this thesis analyzed the microstructure of the welded joints and the formation of the law,the joint consists of nugget zone,semi-melt zone and heat affect zone.Due to very short time in welding and the large cooling rate of the joint,the transformation of austenite in the nugget suppresses,and the microstructure of the nugget refines remarkably,the microstructure of HAZ uncharges.When the capacitor discharge welding voltage of 20 V,Capacitance 40 mF obtained excellent performance and high-quality welding joints.Due to temperature changes during welding seam area has great influence on the organization and performance of the final weld and heat affected zone,known exactly of the temperature changing process is carried out metallurgical analysis,stress-strain analysis and welding process control premise,finite element simulates the welding temperature field,and the simulation results based on the establishment of a database and the temperature field prediction welding temperature field.A looped wire saw machine is developded basis of the reconstruction of a ring-shaped electroplated diamond wire saw machine tools,high speed cutting to perform an experiment tests the performance of welded wire saw which is looped cutting speed meets the requirements of high-speed wire saws. |
