Simulation and Experimental Study on Reverse Helical Milling with the Gradual-Removal Reverse Edge Milling Cutter under Ultrasonic-Assisted Condition.

Kemeng Ren,Guangyue Wang

doi:10.3390/ma15031117

Abstract

As a new machining method, ultrasonic-assisted bi-direction helical milling has obvious advantages in making holes on carbon fiber-reinforced plastics (CFRP). However, cutting edges of the flat-bottomed milling cutter are easy to wear, which may cause severe defects such as burrs and tears in the outlet of the hole. In order to improve the hole-making quality of CFRP, the gradual-removal reverse edge milling cutter was proposed and designed. The finite method models of reverse helical milling CFRP with the flat-bottomed reverse edge milling cutter and the gradual-removal reverse edge milling cutter under an ultrasonic vibration were established, and the comparative cutting experiments of the two cutters were carried out. By comparing the cutting performance of the two milling cutters under the condition of ultrasonic vibration assistance, the cutting mechanism of improving the hole wall quality by the gradual-removal reverse edge milling cutter was studied. The results showed that when the reverse cumulative cutting depth reached about 60 mm, compared with the flat-bottomed reverse edge milling cutter, the gradual-removal reverse edge milling cutter transferred part of the cutting task of the peripheral edge to the end edge, and the wear of the reverse peripheral edges which directly affects the hole quality was effectively alleviated. This mechanism made the cutting state of the peripheral edge dominated by shear failure, which led to the significant improvement of the quality at the outlet of the hole.

Highlights

Carbon fiber-reinforced plastics (CFRP) is widely used in advanced manufacturing fields, such as aviation and aerospace, because of its low density, high strength and excellent mechanical properties [1,2]
In terms of CFRP machining in a helical milling way, Sadek et al [7] carried out comparative experimental research on CFRP helical milling and traditional drilling, and the results showed that, compared with conventional drilling, the cutting temperature and axial force of helical milling holes were lower and the quality of holes were significantly improved
Wang et al [8] put forward a comparative experimental scheme for helical milling and drilling of CFRP with the same feed speed, and the results showed that the lower cutting temperature was the main reason for the higher quality of helical milling holes

Summary

Introduction

Carbon fiber-reinforced plastics (CFRP) is widely used in advanced manufacturing fields, such as aviation and aerospace, because of its low density, high strength and excellent mechanical properties [1,2]. CFRP is mostly used as key structural parts in aircrafts, and a large number of high-precision assembly connecting holes are often required to be machined in the assembly process [3]. The helical milling method is gradually becoming widely used in CFRP high-precision hole making because of its advantages, such as low cutting temperature, fast heat dissipation, large chip removal space, small axial force, short machining time, and good hole quality [4]. Different from the traditional drilling method, the movement form of the helical milling tool is more complex, which consists of two parts. Axial vibrations can change the motion form of the tool, thereby affecting the material removal behavior

Results

Discussion

Conclusion