基于微量润滑的超声振动辅助切削加工性能研究OA

Nickel-based superalloy(GH4169)exhibits excellent mechanical properties under high-temperature and high-stress conditions,making it widely used in aerospace and defense industries.However,during milling,the material is prone to high cutting forces and temperatures,leading to rapid tool wear and compromised surface quality of the workpiece.While ultrasonic vibration can mitigate these issues to some extent.Its inherent limitations in lubrication and cooling make it insufficient for effective interfacial lubrication and heat dissipation.To address these challenges,this study proposes a milling method combining Minimum Quantity Lubrication(MQL)with ultrasonic vibration,thereby improving lubrication conditions.The research systematically investigates the mechanism and effectiveness of this technique in achieving high-efficiency,high-quality machining of nickel-based superalloy through three aspects:capillary lubrication permeation mechanism,thermodynamic simulation analysis,and milling experimental validation.The main contributions are as follows: Based on the capillary action theory of the tool-chip contact zone and the stress distribution,the regular triangular pyramid model and the spatial conditions for cooling lubricant entering the capillary tube are proposed.The penetration and lubrication mechanisms of cutting fluid on the tool are described,a regular triangular pyramid capillary tube model is established,and dynamic analysis is conducted.Friction is incorporated into the analysis to study the lubrication and cooling effects of minimal lubricant in the tool-chip contact zone.The capillary phenomenon of the regular triangular pyramid is further revealed through the wear morphology characteristics on the rake face of the tool. By establishing interface friction models,heat conduction models,and constitutive models,a thermodynamic analysis of milling nickel-based superalloy is conducted,and a three-dimensional thermal-mechanical coupling finite element model is constructed.The influence of minimal quantity lubrication parameters,including friction coefficients and thermal conductivity,on milling forces and temperatures is systematically analyzed.Additionally,the effect of milling speed,feed per tooth,ultrasonic amplitude,and radial depth of cut on milling forces and temperatures is investigated.It is revealed that ultrasonic vibration effectively reduces tool-chip interface friction and contact time through periodic contact-separation,while minimal quantity lubrication further enhances cooling and friction-reducing effects,significantly improving both cutting forces and temperature distribution. An experimental system for micro-irrigation-assisted ultrasonic milling is constructed,and process experiments are conducted using nickel-based superalloy materials.Utilizing detection equipment such as dynamometers and infrared thermal imagers,the influence mechanisms of core process parameters including milling speed,feed per tooth,ultrasonic amplitude,and radial depth of cut-on milling forces and temperatures are thoroughly investigated.Experimental results show that under composite machining conditions,GH4169 milling force is reduced by 20%-35%compared with dry cutting.When the ultrasonic amplitude increases from 0 to 3 μm,milling force drops from about 60 N to 50 N,and the maximum cutting temperature decreases by up to 14.8%.The simulation and experimental results well coincide,fully verifying the accuracy and reliability of the simulation model.The research confirms that MQL lubrication and ultrasonic dynamic cutting show significant synergistic effects,effectively compensating for the shortcomings of single processes,significantly reducing tool-chip interface friction,suppressing cutting temperature rise,slowing tool wear,and improving workpiece surface quality.The composite machining method and microscale mechanisms proposed in this paper effectively improve the theory of vibratory lubrication composite machining of superalloys,providing new technical ideas and theoretical support for efficient,green,and low-damage precision milling of nickel-based superalloys.