Papers by Keyword: Rake Angle

Abstract: Parallel turning is one among the advanced unconventional turning process. It employs two turning tools operating concurrently to cut the material from the workpiece. For turned rotary components, surface integrity is a major quality indicator that determines the fatigue life of the finished workpiece. Tool parting distance, rake angle and edge radius affects surface integrity. Part I dealt with numerical analyses to determine the effect of parting distance on surface integrity using finite element based commercial software Abaqus 6.14. Here in Part II, the impact of rake angle over surface integrity for various cutting speeds and feeds are numerically analyzed. It was observed that with the rise in negative rake angle the negative residual stresses decreased for the machined surface of leading and lagging cutting tool. When the rake angle is increased from-10 ̊ to-2 ̊, percentage reduction of negative residual stresses is same for the turned surfaces of both tools. The cutting velocity was 250 m/min and feed 0.2 mm/rev. With the rise in rake angle, the friction angle reduced but shear angle raised. When the cutting velocity increased, the shear angle of the leading and lagging cutting tool reduced. Lower shear angle causes higher stagnation region which further causes higher compressive surface residual stress.

Abstract: A simulation of the material removal by a single abrasive grain in nanometric grinding is presented in this paper. Molecular Dynamics method is used for modeling the diamond grain and the copper workpiece. The Morse potential function is used to simulate the interactions between the atoms involved in the procedure. The abrasive grain follows a trajectory with decreasing depth of cut within the workpiece to simulate the interaction of the grain with the workpiece. The influence of the grain shape, being either square or rectangular, and of the orientation of the grain, where the grain has rake angle 10^o, -10^o and-20^o, are studied. From the analysis it is apparent that both grain morphology and orientation play a significant role on chip formation, grinding forces and temperatures. With the appropriate modifications, the proposed model can be used for the simulation of various nanomachining processes and operations, in which continuum mechanics cannot be applied or experimental techniques are subjected to limitations.

Abstract: Inorder to analyze the influence of the grinding wheel parameters on the spiralgroove parameters in the grinding process of spiral groove, this paper analyses indetail the influence of grinding wheel radius, fillet radius and grinding wheelcone angle on the rake angle and the opening angle of the spiral groove basedon the spiral groove mathematical model of the end mill. And two polynomial werefitted between the grinding wheel fillet and the rake angle of spiral groove. Studieshave shown that: when the wheel attitude angle remains unchanged, the fillet ofgrinding wheel influence the rake angleand opening angle of spiral groove significantly; the cone angle of grindingwheel affects the opening angle largely; the radius and cone angle of grindingwheel have the weak influence on the rake angle of spiral groove.

Abstract: Micro-machining of hard dies and molds for optical parts or precision instruments is required to extend die and mold life. This paper investigates the effect of cutting fluid on diamond tool life under micro V-groove turning of cobalt-free tungsten carbide. Zinc dialkyldithiophosphate fluid (ZnDTP) displayed excellent diamond tool wear resistance in previous experiments. The performance of this cutting fluid is compared to newly developed vegetable oil based cutting fluid with dispersed MoS₂ nanotubes. This paper investigates nanopolycrystalline diamond (NPD) tool life with a rake angle of 0° and-30° under continuous micro V-groove turning (i.e. face turning), of cobalt-free tungsten carbide using the developed cutting fluids. Superior diamond tool edge wear resistance is observed when using the dispersed MoS₂ nanotubes in vegetable oil and using a NPD tool with a-30° rake angle.

Abstract: This study evaluates the machinability of titanium alloy, Ti6Al4V in terms of tool-chip interface temperature, cutting forces and tool stresses by varying rake angle of PCD insert and compares the results with TiAlN coated carbide inserted end mill using finite element numerical simulations. It has been found that tool rake angle has significant effect and behaves differently for different evaluation parameters and also shows different behavior for two different cutting material inserts. It reduces cutting forces with every positive angle geometry, about 50% reduction is observed for both cutting tool materials for a change in angle from-7° to 34°, but for tool-chip interface temperature, 15% reduction has been observed when angle is changed from-7° to 15° but it starts rising again when angle is increased to 34° for PCD insert, but for TiAlN coated carbide insert a continuous drop of about 20% has been observed. For tool stresses tool rake angle has different effect. The stresses remains almost unchanged when angle is changed from-7° to 15° but increased by almost 20% when angle is changed to 34° for both insert materials. Results also have shown that PCD insert due to its excellent thermal conductivity and strength at elevated temperatures dissipates most of the heat into the chip and has almost half temperature near the tool edge as compared to TiAlN coated carbide insert and thus can be used for machining of Ti6Al4V alloy at much higher cutting speeds than TiAlN coated carbide insert with positive rake angle geometries (around 15°).

Abstract: Formation of chip is a typical severe plastic deformation progress in machining which is only single deformation stage. The rake angle of tool is governing parameter to create large strain imposed in the chip. Effect of rake angle and deformation times on effective strain, mean strain, strain variety and strain rate imposed in the chip are researched respectively. The result of simulation have shown that the chip with large strain and better uniform of strain along the longitudinal section of chip can be produced with negative rake angle at some lower cutting velocity by multi-deformations in large strain machining.

Abstract: A finite element model (FEM) of an orthogonal metal-cutting process is used to study the influence of tool rake angle on the cutting force and tool temperature. The model involves Johnson-Cook material model and Coulomb’s friction law. A tool rake angle ranging from 0° to 20° and a cutting speed ranging from 300 to 600 m/min were considered in this simulation. The results of this simulation work are consistent optimum tool rake angle for high speed machining (HSM) of AISI 1045 medium carbon steel. It was observed that there was a suitable rake angle between 10° and 18° for cutting speeds of 300 and 433 m/min where cutting force and temperature were lowest. However, there was not optimum rake angle for cutting speeds of 550 and 600 m/min. This paper can contribute in optimization of cutting tool for metal cutting process.

Abstract: The article examines the change of the slip-line fields structure with the help of numerical simulation (FEM) in the case of hard turning by gradually decreasing the tool rake angle. During the examination the influencing effect of the stagnation zone on the chip removal was taken into consideration. The stagnation zone is typical of the cutting done by a negative rake angle and it is generally present in front of the tool tip.

Abstract: This paper presents the mathematical model of helical groove of the end mill according to the differential geometry and meshing principle based on the grinding wheel attitude. The profile of the helical groove can be precisely calculated using a given wheel attitude and the relative motion between the workpiece and the grinding wheel.The relation between the grinding wheel attitude and the rake angle can be obtained through adjusting the grinding wheel attitude angle.And the accurate 3D model of helical groove was generated in the SolidWorks.The research shows that the grinding wheel attitude is the main factor that affects the rake angle of end mill.There is a linear relationship between the rake angle and the grinding wheel attitude. The smooth and accurate 3D model of helical groove lay the foundation for studying the cutting performance and dynamic characteristics of end mill.

Abstract: In this paper the residual stresses are investigated emerging in the machined layer during hard turning in case of chip removal done by different tool rake angles. By means of finite element method simulation we examined what rake angle is best to complete cutting so that favourable residual stress values are gained in the machined surface layer.