No abstract

Due to the strong plasticity of Inconel 718 and the significant size effect of micromachining, a large number of burrs will be produced in traditional processing. The addition of ultrasonic vibration during machining can reduce the burr problem. The mechanism of burr generation in traditional micromilling (TMM) and ultrasonic vibration-assisted micromilling (UVAMM) was analyzed by simulation, and verified by corresponding experiments. It is found that applying high-frequency ultrasonic vibration in the milling feed direction can reduce cutting temperature and cutting force, improve chip breaking ability, and reduce burr formation. When the cutting thickness will reach the minimum cutting thickness hmin, the chip will start to form. When A/ƒz > 1/2, the tracks of the two tool heads start to cut, and the chips are not continuous. Some of the best burr suppression effects were achieved under conditions of low cutting speed (Vc), feed per tooth (ƒz), and large amplitude (A). When A is 6 μm, the size and quantity of burr is the smallest. When ƒz reaches 6 μm, large continuous burrs appear at the top of the groove. The experimental results further confirm the accuracy of the simulation results and provide parameter reference.

In the traditional micromilling(TMM) of Inconel718 alloy, due to the influence of material plas ticity and size effect, relatively large burr will be produced. In order to solve the burr proble m in micromilling, ultrasonic vibration in feed direction is applied to the workpiece to complet e vibration cutting. Combined with trajectory simulation and cutting experiment, the burr forma tion mechanism of TMM and ultrasonic vibration assisted micromilling(UVAMM) was studied.The results show that when the ratio of amplitude(A) to feed per tooth(ƒz) is greater than 0.5, continuous cutting changes to intermittent cutting. Compared with TMM, UVAMM improves ch ip breaking ability, facilitates the propagation of burr crack and effectively inhibits the formatio n of burr. However, due to the influence of cutting edge radius, A/ƒz should be set larger. Wh en the chip breaking condition is reached, the burr shape is usually tearing or flocculent. Unde r the conditions of low speed(n), large ƒz and large A, the burr suppression is more obvious.