Study On The Influence Of Ultrasonic Vibration Direction On Material Removal Behavior In Ultrasonic Assisted Grinding

Due to its excellent performance,glass ceramics are not only applied in the field of architectural decoration,daily necessities and mechanical engineering,but also widely used in high-precision fields such as military facilities,biomedicine,aerospace and electronics.For the processing of difficult-to-machine materials such as glass ceramics,ultrasonic assisted grinding is considered a promising processing method because of its lower grinding force,higher material removal rate and better processing quality.At present,the research on the mechanism of ultrasonic assisted grinding has become the key to improve the processing effects.It is found that most of the studies focused on the mechanism of ultrasonic assisted grinding in different vibration directions or ultrasonic vibration assisted scratching in a single direction.There are no studies focusing on ultrasonic vibration assisted scratching in different vibration directions and analyzing the inner relationship of scratch morphological characteristics,scratching force and material removal rate.In view of the problems above,this article compares ultrasonic vibration assisted scratching in different directions with non-ultrasonic vibration assisted scratching on glass ceramics.To describe the test conditions and results more clearly,the ultrasonic vibration is divided into X-direction ultrasonic vibration,Y-direction ultrasonic vibration and Z-direction ultrasonic vibration based on the workpiece coordinate system.First,the scratching force is measured during the scratching tests,and the material removal mechanism of ultrasonic vibration assisted scratching in different directions is explored.To analyze the reasons why ultrasonic vibration assisted scratching in different vibration directions can reduce scratching force,the two component forces(normal force and tangential force)of the scratching force are linearly fitted,the effects of different vibration directions on the scratching force are discussed combining the morphological characteristics of the scratches.Second,the ability to remove the material of ultrasonic vibration assisted scratching is probed by measuring the cross-sectional area of the scratch at the same depth.The value of the cross-sectional area can reflect the ability to remove the material.Different ultrasonic vibration directions have different effects on the ability to wipe off material and the material removal mechanisms are also different.At the same time,considering morphology of the scratches’ entry part,the material removal mechanisms of different ultrasonic vibration directions are analyzed thoroughly.Third,the morphology features in ultrasonic assisted scratching are observed focusing on the entry part of the scratches,compared with those in conventional scratching.The reasons of the formation of scratches’ features are explored from three perspectives(the residual stress,fracture toughness and system’s energy).The relationship between scratching force and scratches’ morphology is comprehensively analyzed considering the scratches’ morphology results of scratching force.So as to the relationship between material removal rate and scratches’ morphology.At last,the effects of different vibration directions on scratching hard and brittle materials based on the scratches’ characters in three vibration directions are summarized.The relationship between the extent of scratching force reduction and the direction of ultrasonic vibration is studied to integrate the machining mechanism of ultrasonic vibration assisted scratching hard and brittle materials after investigate material removal mechanism thoroughly.