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• A 3D friction model is developed based on oblique cutting theory. • Conventional and ultrasonic assisted turning and face turning are simulated. • Cutting forces and cutting angles determine the friction value. • The differences of forces plus inclination and rake angles are very effective on friction value. As turning is a 3D operation, development of a friction model considering all cutting forces and angles, is essential. In this study, shear friction model is extended based on oblique cutting theory. The developed model calculates friction value using measured cutting forces coupled with their related angles. To use the model, the operation is carried out in two methods of turning and face turning (with and without ultrasonic vibrations). Then the friction values based on experimental results are calculated. A finite element method is developed to evaluate the accuracy of the values. The results show that the values of simulated tool temperatures are in good agreement with the experiments. Furthermore, the effect of cutting forces on friction values are discussed. [ABSTRACT FROM AUTHOR]

Highlights • Analytical model of ultrasonic burnishing force has been developed. • Effect of ultrasonic vibration has been included. • Effect of surface elastic recovery has been included. • The results of analytical model were in line with experimental measurements. Abstract In our recently published work i.e. Teimouri et al. [25], mechanic of forces acting during burnishing process has been identified and fully discussed. The process was modeled based on slab method theorem and effect of burnishing parameters on horizontal and vertical forces were identified. However, the present work is an analytical approach to find effect of ultrasonic vibration parameters and pass number considering elastic rebound of work surface. In the proposed methodology effect of different parameters such as feed rate, ball diameter, depth of burnishing, vibration amplitude and pass number on the burnishing force. The comparison with experimental results allows to affirm that the model is a useful tool to predict the value of resultant burnishing force. [ABSTRACT FROM AUTHOR]

In this study, ultrasonic assisted drilling (UAD) is performed to investigate the effect of ultrasonic vibrations on common difficulties existed in conventional drilling (CD). UAD is a promising and advanced technique by which a harmonic movement with high frequency and low amplitude is superimposed on the movement of work material or cutting tool. The study is conducted both experimentally and numerically; at first, a UAD system is designed, manufactured, and carried out on a milling machine and then experimental tests are accomplished. In the following, experimental results are supported by the help of three-dimensional (3D) finite element simulation. Finally, the dependent parameters such as the burr height and cylindricity of the ultrasonically and conventionally drilled workpiece are measured and compared. Briefly, it was proved that the intermittent movement of drill bit in the direction of feed rate results in broken and discontinuous chips by which built-up-edge (BUE) is reduced and hole quality is improved. In addition, the burr height, which is known as unwanted projection of material at the exit surface of pieces, can notably decrease, if UAD is considered. [ABSTRACT FROM AUTHOR]

Conventional drilling (CD) which is known by two rotary and linear motions is considerably used in material removal processes; however, this method cannot satisfy the new demands of modern industry anymore, encountering with some serious technological constraints such as fast tool wear, high thrust force, and so on. A new and promising method which has been used recently as an alternative technique to cope or at least diminish common difficulties in CD is imposing ultrasonic vibrations to the cutting process, where vibrations usually with high frequency and low amplitude are superimposed in the movements of cutting tool. This study is a new exercise which considers the effects of one and two directional ultrasonic vibrations in drilling of AISI 1045 compared to CD. In one directional technique known as longitudinal ultrasonic assisted drilling (L UAD), ultrasonic vibrations are added to the feed motion and in two directional vibrations; ultrasonic vibrations are simultaneously applied to both feed and rotary motions known as longitudinal-torsional ultrasonic assisted drilling (L-T UAD). The study which is performed both experimentally and numerically does its best to evaluate and compare the obtained results in CD, L UAD, and L-T UAD. In experimental part, a system including two vibratory tools and a rotary mechanism is designed, fabricated, and then assembled with other equipment on a milling machine to accomplish drilling tests. In numerical part, a FE model is also developed with the aim of further understanding of experimental results, by which drilling operations either conventional or vibratory in different forms can be conducted and studied. As a brief conclusion, it was found that ultrasonic vibrations can be used as an effective tool for enhancement of drilling process and longitudinal-torsional vibrations reveal better results than longitudinal vibrations. [ABSTRACT FROM AUTHOR]

In this study, 3D finite element simulation of ultrasonically-assisted drilling is carried out to analyze the effect of ultrasonic vibrations on common difficulties existed in conventional drilling. Influence of harmonic movement of drill bit on the formation of built-up edge is experimentally evaluated and also discussed by investigation of heat generation on the tool faces in simulation. At the end, it was revealed that intermittent movement of drill bit in vibration method causes the total time of heat transfer between workpiece and drill bit to be reduced resulting lower built-up edge formation compared to conventional drilling. Moreover, linear motion of cutting tool in the feed direction results in the increase of chip strain and consequently damage value which causes to generation of broken chips. [ABSTRACT FROM AUTHOR]