Tool/Chip Interfacial Friction Analysis in Atomistic Machining of Polycrystalline Coppers

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.

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

A three-dimensional molecular dynamics (MD) model is developed to study the tool/chip interface stress distributions in machining of polycrystalline copper at atomistic scale. Three polycrystalline copper structures with equivalent grain sizes of 12.25, 7.72, and 6.26 nm are constructed for simulation. Also, a monocrystalline copper structure of the same dimension is simulated as the benchmark case. In addition to the grain size, the effects of depth of cut and cutting speed are also considered. The friction force and normal force profiles along the tool/chip interface in both polycrystalline and monocrystalline nano-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 still smaller than that in the monocrystalline case. In polycrystalline nano-machining, 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, the stress profiles are also significantly affected by the cutting speed.


Author(s):  
Kadir Gok ◽  
Hüseyin Sari ◽  
Arif Gok ◽  
Süleyman Neseli ◽  
Erol Turkes ◽  
...  

In this study, milling operations were carried out using AISI 1040 specimens steel in dry cutting conditions. The cutting tools used in the experiment include P20 tool steel and they also have three different approach angles (45°, 60°, 75°) and rake angles (0°, −6°, −12°). In milling experiments, cutting parameters with a depth of cut of 1.5 mm, cutting speed of 193 m/min, and feed rate of 313 mm/min were selected. A comparison was presented between the force values which were obtained by measured value and predicted with numerical simulations, and then a good agreement was found between measured and predicted force values. As result of, it was observed that the rake and approach angles were effective in milling operations.


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.


Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Panagiotis Kyratsis ◽  
Anastasios Tzotzis ◽  
Angelos Markopoulos ◽  
Nikolaos Tapoglou

In this study, the development of a 3D Finite Element (FE) model for the turning of AISI-D3 with ceramic tooling is presented, with respect to four levels of cutting speed, feed, and depth of cut. The Taguchi method was employed in order to create the orthogonal array according to the variables involved in the study, reducing this way the number of the required simulation runs. Moreover, the possibility of developing a prediction model based on well-established statistical tools such as the Response Surface Methodology (RSM) and the Analysis of Variance (ANOVA) was examined, in order to further investigate the relationship between the cutting speed, feed, and depth of cut, as well as their influence on the produced force components. The findings of this study point out an increased correlation between the experimental results and the simulated ones, with a relative error below 10% for most tests. Similarly, the values derived from the developed statistical model indicate a strong agreement with the equivalent numerical values due to the verified adequacy of the statistical model.


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.


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.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Sandeep Kuriakose ◽  
Paolo Parenti ◽  
Salvatore Cataldo ◽  
Massimiliano Annoni

Additive manufacturing (AM) of metal offers matchless design sovereignty to manufacture metallic microcomponents from a wide range of materials. Green-state micromilling is a promising method that can be integrated into the AM of metallic feedstock microcomponents in typical extrusion-based AM methods for compensating the inability to generate microfeatures. The integration enables the manufacturing of complex geometries, the generation of good surface quality, and can provide exceptional flexibility to new product shapes. This work is a micromachinability study of AISI316 L feedstock components produced by extrusion-based AM where the effects of workpiece temperature and the typical micromilling parameters such as cutting speed, feed per tooth, axial depth of cut, and air supply are studied. Edge integrity and surface roughness of the machined slots, as well as cutting forces, are analyzed using three-dimensional microscopy and piezoelectric force sensor, respectively. Green-state micromilling results were satisfying with good produced quality. The micromilling of heated workpieces (45 °C), with external air supply for debris removal, showed the best surface quality with surface roughness values that reached around Sa = 1.5 μm, much smaller than the average metal particles size. Minimum tendency to borders breakage was showed but in some cases microcutting was responsible of the generation of surface defects imputable to lack of adhesion of deposited layers. Despite this fact, the integrability of micromilling into extrusion-based AM cycles of metallic feedstock is confirmed.


Author(s):  
O Kalantari ◽  
MM Fallah ◽  
F Jafarian ◽  
SR Hamzeloo

In laser-assisted machining (LAM), the laser source is focused on the workpiece as a thermal source and locally increases the workpiece temperature and makes the material soft ahead of the cutting tool so using this method, the machining forces are reduced, which causes improving the surface quality and cutting tool life. Machinability of advanced hard materials is significantly low and conventional methods do not work effectively. Therefore, utilizing an advanced method is inevitable. The product life and performance of complex parts of the leading industry depends on surface integrity. In this work, the surface integrity features including microhardness, grain size and surface roughness (Ra) and also the maximum cutting temperature were investigated experimentally in LAM of Ti-6Al-4V. According to the results, cutting speed has inverse effect on the effectiveness of LAM process because with increasing speed (15 to 63 m/min), temperature decreases (524 °C to 359 °C) and surface roughness increases (0.57 to 0.71 μm). Enhancing depth of cut and feed has direct effect on the process temperature, grain size, microhardness and surface roughness.


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