Impact of Tool Geometry on Cutting Dynamics

Author(s):  
Achala V. Dassanayake ◽  
C. Steve Suh

Machining stability in response to changing tool geometry is studied using a 3D turning model that considers coupled tool-workpiece dynamics subject to nonlinear regenerative cutting forces [1]. As tool geometry varies with the specified tool angles, values of tool rake angle, side cutting edge angle, and inclination angle are considered in the study as the controlled parameters. In the presented model, cutting force components in the X, Y, and Z directions vary with the variations of tool geometry, thus resulting in changes in cutting dynamics — a major feature not attainable using 1D models. It is found that tool geometry does have a significant effect on machining stability. In contrast to commonly used stability charts that are created by considering varying cutting speed and depth-of-cut (DOC), the study makes an observation that tool geometry can be a variable effective in restoring an unstable system back to stability without having to resort to changing cutting speed, feed rate or DOC.

Author(s):  
İsmail Kırbaş ◽  
Musa Peker ◽  
Gültekin Basmacı ◽  
Mustafa Ay

In this chapter, the impact of cutting parameters (depth of cut, cutting speed, feed, flow, rake angle, lead angle) on cutting forces in the turning process with regard to ASTM B574 (Hastelloy C-22) material has been investigated. Variance analysis has been applied in order to determine the factors affecting the cutting forces. The optimization of the parameters affecting the surface roughness has been obtained using response surface methodology (RSM) based on the Taguchi orthogonal experimental design. The accuracy of the developed models required for the estimation of the force values (Fx, Fy, Fz) is quite successful. In this study, where the R2 value has been used as the criterion/measure, accuracy values of 93.35%, 95.03%, and 95.09% have been achieved for Fx, Fy, and Fz, respectively. As a result of the ANOVA analysis, the most effective parameters for Fx at a 95% confidence interval are depth of cut, feed rate, flow, and rake angle. The most effective parameter for Fy is depth of cut, while the most effective parameters for Fz are depth of cut, feed rate, and flow, respectively.


2016 ◽  
Vol 836-837 ◽  
pp. 168-174 ◽  
Author(s):  
Ying Fei Ge ◽  
Hai Xiang Huan ◽  
Jiu Hua Xu

High-speed milling tests were performed on vol. (5%-8%) TiCp/TC4 composite in the speed range of 50-250 m/min using PCD tools to nvestigate the cutting temperature and the cutting forces. The results showed that radial depth of cut and cutting speed were the two significant influences that affected the cutting forces based on the Taguchi prediction. Increasing radial depth of cut and feed rate will increase the cutting force while increasing cutting speed will decrease the cutting force. Cutting force increased less than 5% when the reinforcement volume fraction in the composites increased from 0% to 8%. Radial depth of cut was the only significant influence factor on the cutting temperature. Cutting temperature increased with the increasing radial depth of cut, feed rate or cutting speed. The cutting temperature for the titanium composites was 40-90 °C higher than that for the TC4 matrix. However, the cutting temperature decreased by 4% when the reinforcement's volume fraction increased from 5% to 8%.


2011 ◽  
Vol 418-420 ◽  
pp. 1482-1485 ◽  
Author(s):  
Erry Yulian Triblas Adesta ◽  
Muataz Al Hazza ◽  
Delvis Agusman ◽  
Agus Geter Edy Sutjipto

The current work presents the development of cost model for tooling during high speed hard turning of AISI 4340 hardened steel using regression analysis. A set of experimental data using ceramic cutting tools, composed approximately of Al2O3 (70%) and TiC (30%) on AISI 4340 heat treated to a hardness of 60 HRC was obtained in the following design boundary: cutting speeds (175-325 m/min), feed rate (0.075-0.125 m/rev), negative rake angle (0 to -12) and depth of cut of (0.1-0.15) mm. The output data is used to develop a new model in predicting the tooling cost using in terms of cutting speed, feed rate, depth of cut and rake angle. Box Behnken Design was used in developing the model. Predictive regression model was found to be capable of good predictions the tooling cost within the boundary design.


1984 ◽  
Vol 30 (104) ◽  
pp. 77-81 ◽  
Author(s):  
D.K. Lieu ◽  
C.D. Mote

AbstractThe cutting force components and the cutting moment on the cutting tool were measured during the orthogonal machining of ice with cutting tools inclined at negative rake angles. The variables included the cutting depth (< 1 mm), the cutting speed (0.01 ms−1to 1 ms−1), and the rake angles (–15° to –60°). Results of the experiments showed that the cutting force components were approximately independent of cutting speed. The resultant cutting force on the tool was in a direction approximately normal to the cutting face of the tool. The magnitude of the resultant force increased with the negative rake angle. Photographs of ice-chip formation revealed continuous and segmented chips at different cutting depths.


2013 ◽  
Vol 433-435 ◽  
pp. 2101-2106
Author(s):  
Joon Hwang ◽  
Ey Hyoun Jeong ◽  
Eui Sik Chung ◽  
Steven Y. Liang

Machining performance is often limited by chatter vibration at the tool-workpiece interface. Chatter is a type of machining self-excited vibration which originates from the variation in cutting forces and the flexibility of the machine tool structure. Machining chatter is an inherently nonlinear phenomenon that is affected by many parameters such as cutting conditions, tool geometry, cutting speed, feed rate, depth of cut, overhang length of tool, clamping condition of workpiece. This study presents experimental approach for investigation of effects of various cutting tool geometry on the onset of chatter. In turning process, measured cutting force signal and triaxial accelerometer signal was used to know the characteristics of chatter vibration. The static and dynamic component of cutting forces reflect onset of chatter vibration. Proper selection of tooling is an important parameter in terms of chatter elimination in machining.


1996 ◽  
Vol 118 (3) ◽  
pp. 419-425 ◽  
Author(s):  
G. Caprino ◽  
L. Nele

The results of orthogonal cutting tests carried out on unidirectional glass fiber reinforced plastic composites, using HSS tools, are presented and discussed. During the tests, performed on a milling machine at very low cutting speed to avoid thermal effects, the cutting speed was held constant and parallel to the fibre direction. Three parameters, namely the tool rake angle α, the tool relief angle γ, and the depth of cut t, were varied. According to the experimental results, the horizontal force per unit width, Fhu, undergoes a dramatic decrease, never verified for metals, with increasing α. Besides, Fhu is only negligibly affected by the relief angle, and linearly increases with t. Similarly to metals, an effect of the depth of cut on the specific energy (size effect) is found also for composites. However, the presented results indicate that the size effect can be analytically modeled in a simple way in the case of composites. The vertical force per unit width, Fvu, exhibits a marked reduction when the relief angle is increased. Fvu, is also very sensitive to the rake angle: the lower α the higher is Fvu. It is shown that this behavior probably reflects a strong influence of the rake angle on the forces developing at the flank. A linear dependence of the vertical force on the depth of cut is also demonstrated. Finally, the experimental data are utilized to obtain empirical formulae, allowing an approximate evaluation of cutting forces.


2014 ◽  
Vol 2 (4) ◽  
Author(s):  
Jing Shi ◽  
Chunhui Ji ◽  
Yachao Wang ◽  
Steve Hsueh-Ming Wang

Three-dimensional (3D) molecular dynamics (MD) simulation is performed to study the tool/chip interface friction phenomenon in machining of polycrystalline copper at atomistic scale. Three polycrystalline copper structures with the equivalent grain sizes of 12.25, 7.72, and 6.26 nm are constructed for simulation. Also, a monocrystalline copper structure is simulated as the benchmark case. Besides the grain size, the effects of depth of cut, cutting speed, and tool rake angle are also considered. It is found that the friction force and normal force distributions along the tool/chip interface in both polycrystalline and monocrystalline machining exhibit similar patterns. The reduction in grain size overall increases the magnitude of normal force along the tool/chip interface, but the normal forces in all polycrystalline cases are smaller than that in the monocrystalline case. In atomistic machining of polycrystalline coppers, the increase of depth of cut consistently increases the normal force along the entire contact area, but this trend cannot be observed for the friction force. In addition, both higher cutting speed and more negative tool rake angle do not bring significant changes to the distributions of normal and friction forces on the interface, but both factors tend to increase the magnitudes of the two force components.


2018 ◽  
Vol 14 (1) ◽  
pp. 67-76
Author(s):  
Mohanned Mohammed H. AL-Khafaji

The turning process has various factors, which affecting machinability and should be investigated. These are surface roughness, tool life, power consumption, cutting temperature, machining force components, tool wear, and chip thickness ratio. These factors made the process nonlinear and complicated. This work aims to build neural network models to correlate the cutting parameters, namely cutting speed, depth of cut and feed rate, to the machining force and chip thickness ratio. The turning process was performed on high strength aluminum alloy 7075-T6. Three radial basis neural networks are constructed for cutting force, passive force, and feed force. In addition, a radial basis network is constructed to model the chip thickness ratio. The inputs to all networks are cutting speed, depth of cut, and feed rate. All networks performances (outputs) for all machining force components (cutting force, passive force and feed force) showed perfect match with the experimental data and the calculated correlation coefficients were equal to one. The built network for the chip thickness ratio is giving correlation coefficient equal one too, when its output compared with the experimental results. These networks (models) are used to optimize the cutting parameters that produce the lowest machining force and chip thickness ratio. The models showed that the optimum machining force was (240.46 N) which can be produced when the cutting speed (683 m/min), depth of cut (3.18 mm) and feed rate (0.27 mm/rev). The proposed network for the chip thickness ratio showed that the minimum chip thickness is (1.21), which is at cutting speed (683 m/min), depth of cut (3.18 mm) and feed rate (0.17 mm/rev).


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4427
Author(s):  
Antoni Świć ◽  
Arkadiusz Gola ◽  
Olga Orynycz ◽  
Karol Tucki

Low-rigidity thin-walled parts are components of many machines and devices, including high precision electric micro-machines used in control and tracking systems. Unfortunately, traditional machining methods used for machining such types of parts cause a significant reduction in efficiency and in many cases do not allow obtaining the required accuracy parameters. Moreover, they also fail to meet modern automation requirements and are uneconomical and inefficient. Therefore, the aim of provided studies was to investigate the dependency of cutting forces on cutting parameters and flank wear, as well as changes in cutting forces induced by changes in heating current density and machining parameters during the turning of thin-walled parts. The tests were carried out on a specially designed and constructed turning test stand for measuring cutting forces and temperature at specific cutting speed, feed rate, and depth of cut values. As part of the experiments, the effect of cutting parameters and flank wear on cutting forces, and the effect of heating current density and turning parameters on changes in cutting forces were analyzed. Moreover, the effect of cutting parameters (depth of cut, feed rate, and cutting speed) on temperature has been determined. Additionally, a system for controlling electro-contact heating and investigated the relationship between changes in cutting forces and machining time in the operations of turning micro-machine casings with and without the use of the control system was developed. The obtained results show that the application of an electro-contact heating control system allows to machine conical parts and semi-finished products at lower cutting forces and it leads to an increase in the deformation of the thin-walled casings caused by runout of the workpiece.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 840 ◽  
Author(s):  
Rashid Ali Laghari ◽  
Jianguang Li ◽  
Mozammel Mia

Cutting force in the machining process of SiCp/Al particle reinforced metal matrix composite is affected by several factors. Obtaining an effective mathematical model for the cutting force is challenging. In that respect, the second-order model of cutting force has been established by response surface methodology (RSM) in this study, with different cutting parameters, such as cutting speed, feed rate, and depth of cut. The optimized mathematical model has been developed to analyze the effect of actual processing conditions on the generation of cutting force for the turning process of SiCp/Al composite. The results show that the predicted parameters by the RSM are in close agreement with experimental results with minimal error percentage. Quantitative evaluation by using analysis of variance (ANOVA), main effects plot, interactive effect, residual analysis, and optimization of cutting forces using the desirability function was performed. It has been found that the higher depth of cut, followed by feed rate, increases the cutting force. Higher cutting speed shows a positive response by reducing the cutting force. The predicted and experimental results for the model of SiCp/Al components have been compared to the cutting force of SiCp/Al 45 wt%—the error has been found low showing a good agreement.


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