| In order to reduce the cutting force, cutting heat and increase tool lifein cutting process, the cutting fluid is commonly used to cool and lubricatethe tool and workpiece. Cutting fluid often contains kinds of additives,which are carcinogenic. The gasification and atomization of the cuttingfluid in the machining process are more threat to human health andenvironment. Therefore, the green cutting technology has been more andmore attentioned.Minimum quantity lubrication (MQL) uses high-pressure gasatomization nozzle to atomize by a high-pressure air, then sprays non-toxic,biodegradable plant-based lubrication to cutting point. In this paper, sprayperformance, lubrication mechanism and application to difficulty materialthread turning of MQL system were experimented. Atomization principle ofMQL was studied by Particle Image Velocimetry, and two-phase flow fielddistribution in cutting area was acquired. Downstream of nozzle and cuttingzone was simulated by FLUENT software, and two-phase flow field wasfurther researched. Stainless steel external thread turning experiment underdry cutting, MQL and wet lubrication was carried out, the effect oflubrication and cutting parameters to cutting performance was studied thenthe cutting force and thread precision cutting process optimization modelwas established. Main contents are as follows:(1) Use PIV-depth to study the impact of MQL system parameters forthe flow field distribution, including MQL’s atomization mechanism andcutting zone atomization characteristics. Provide a basis for optimizing the MQL system.(2) MQL fluid simulation analysis applied to the thread turning toprovide a theoretical basis for MQL applied to the actual cutting.(3) Stainless steel external thread turning experiment under drycutting, MQL and wet lubrication conditions was studied to understand thelubricating effect of the difference between MQL and other luburcationmethod by analyzing thread precision, cutting force, chip shape and toolwear.(4) Through single-factor analysis to understand how the cuttingspeed, the cutting number and lubrication methods affect to the cuttingforce, chip and thread precision, then offer an optimal process plan for theexternal thread turning. |
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