Study on two-dimensional ultrasonic assisted precision cutting of titanium alloy based on size effect

ObjectivesTo improve the negative effects of size effect on precision machining， enhance the machining accuracy and surface quality of titanium alloy micro-scale cutting，Methodsthe special processing theory was combined with the precision cutting method， a two-dimensional ultrasonic-assisted precision cutting method was proposed. Based on the ABAQUS force-thermal coupling model， the cutting process of two-dimensional ultrasonic-assisted precision cutting of titanium alloy was analyzed， and the cutting mechanical characteristics of precision cutting and two-dimensional ultrasonic-assisted precision cutting were explored. Through experiments， taking the ratio of ultrasonic amplitude， cutting depth to edge radius（ap/rn） as factors， the change rules of cutting force and unit cutting force in ultrasonic vibration cutting under the action of size effect were analyzed. Furthermore， the surface morphology characteristics of precision cutting and two-dimensional ultrasonic vibration cutting under different（ap/rn） values were compared and analyzed.ResultsAs the ratio of cutting depth to edge radius（ap/rn） increased， the surface morphology of precision cutting of titanium alloy showed adhesion， pits， and plowing phenomena， while the surface of two-dimensional ultrasonic-assisted cutting showed uniform and complete reticulated surface texture characteristics. At the same time， the unit cutting force of two-dimensional ultrasonic-assisted cutting was much smaller than that of precision cutting. And as the amplitude increased， the growth ratio of unit cutting force decreased from 57.7% to 45.2%.ConclusionsTwo-dimensional ultrasonic-assisted precision cutting can significantly improve the negative rake angle effect and plowing phenomenon generated by size effect， reduce unit cutting force， and improve the stability of the cutting process. It has important application value in improving the machining accuracy and surface quality of titanium alloy micro-scale cutting chips.