Assessment of the Effects of Microgrooved Cutting Tool on the Machining Induced Residual Stress in Machining of Ti-6Al-4V

Author(s):  
Changqing Qiu ◽  
Jianfeng Ma ◽  
Shuting Lei

In this paper, the effects of microgroove textured cutting tools on the residual stress on the machined surface of drying three-dimensional turning of Ti-6AL-4V are investigated using Finite Element Method (FEM). Microgrooves are designed and fabricated on the rake face of cemented carbide (WC/Co) cutting inserts. Specifically, the following microgroove parameters are examined: microgroove width, microgroove depth, and edge distance (the distance from cutting edge to the first microgroove). Their effects are assessed in terms of the circumferential residual stress. It is found that microgroove textured cutting tools can lower the detrimental tensile residual stress and induce beneficial compressive residual stress on the machined surface. The microgroove width, microgroove depth, and edge distance all have influence on residual stress on the machined surface in their own ways. This research provides insightful guidance for optimizing the fatigue life of the components by inducing beneficial compressive residual stress on the machined surface.

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3432
Author(s):  
Edwin Gevorkyan ◽  
Mirosław Rucki ◽  
Tadeusz Sałaciński ◽  
Zbigniew Siemiątkowski ◽  
Volodymyr Nerubatskyi ◽  
...  

The paper presents results of investigations on the binderless nanostructured tungsten carbide (WC) cutting tools fabrication and performance. The scientific novelty includes the description of some regularities of the powder consolidation under electric current and the subsequent possibility to utilize them for practical use in the fabrication of cutting tools. The sintering process of WC nanopowder was performed with the electroconsolidation method, which is a modification of spark plasma sintering (SPS). Its advantages include low temperatures and short sintering time which allows retaining nanosize grains of ca. 70 nm, close to the original particle size of the starting powder. In respect to the application of the cutting tools, pure WC nanostructure resulted in a smaller cutting edge radius providing a higher quality of TiC/Fe machined surface. In the range of cutting speeds, vc = 15–40 m/min the durability of the inserts was 75% of that achieved by cubic boron nitride ones, and more than two times better than that of WC-Co cutting tools. In additional tests of machining 13CrMo4 material at an elevated cutting speed of vc = 100 m/min, binderless nWC inserts worked almost three times longer than WC-Co composites.


Author(s):  
C. G. Jensen ◽  
J. K. Hill ◽  
K. A. White

Abstract Engineers and designers use a wide variety of curve and surface formulations to describe products. The process of producing the physical shape of these products has remained essentially unchanged for many years. Traditionally, the process of finish surface machining has been error prone and inefficient due in large part to the mathematical basis used to control the positioning, orientation and movement of cutting tools in five-axis machining centers. This paper presents swept silhouette curvature matching algorithms for positioning and orienting a cutter such that tool and surface curvatures match. Formulations are given for both flat and filleted end mill cutters. The benefits of curvature matching are: reduction of local machining errors, reduction or elimination of grinding of the finished machined surface, and the improvement of machine tool efficiency. Examples are given that compare curvature matching to traditional machining methods. The paper concludes by discussing current research into a priori gouge detection methods based on intersection contact between the cutting tool and the design surface or the lower tolerance-bound offset surface to the design surface. An a priori gouge detection algorithm is necessary for the development of optimal tool motion and the reduction of time spent in tool path editing and verification. Techniques involving collinear normals, Bézier clipping, triangulation, normal intersection and swept volumes are suggested as techniques for examining the positional and translational tool gouge problem.


2006 ◽  
Vol 532-533 ◽  
pp. 540-543 ◽  
Author(s):  
Lu Lu Jing ◽  
Gang Liu ◽  
Ming Chen

In die and mold industry, there is a tendency to use milling in the finishing machining of dies and molds as an alternative to the traditional EDM process, consequently the surface integrity in milling is considered as one of the most important indices. In this study, surface roughness, micrograph of machined surface, surface microhardness, residual stress, and metallurgical texture of the surface layer were considered. The influence of geometrical characteristics of cutting tools and tool wear on surface integrity was studied. The results showed that hard milling of hardened die steel could yield a quite satisfied surface integrity by proper process; compressive residual stress was induced on machined surface, and the compressive stress induced in transversal direction was almost 3 times of that in longitudinal direction; tool wear had a significant negative influence on surface finish and caused the machined surface soften. These conclusions revealed the effects of tool conditions on surface integrity and would play a practical significance in the machining of hardened die steel.


2015 ◽  
Vol 66 (1) ◽  
pp. 98-101 ◽  
Author(s):  
Miloš Madić ◽  
Miroslav Radovanović ◽  
Dušan Petković ◽  
Bogdan Nedić

Abstract Machining of aluminum and its alloys requires the use of cutting tools with special geometry and material. Since there exists a number of cutting tools for aluminum machining, each with unique characteristics, selection of the most appropriate cutting tool for a given application is very complex task which can be viewed as a multi-criteria decision making (MCDM) problem. This paper is focused on multi-criteria analysis of VCGT cutting inserts for aluminum alloys turning by applying recently developed MCDM method, i.e. weighted aggregated sum product assessment (WASPAS) method. The MCDM model was defined using the available catalogue data from cutting tool manufacturers.


Author(s):  
Youqiang Xing ◽  
Jianxin Deng ◽  
Xingsheng Wang ◽  
Kornel Ehmann ◽  
Jian Cao

To improve the friction conditions and reduce adhesion at the tool's rake face in dry cutting of aluminum alloys, three types of laser surface textures were generated on the rake face of cemented carbide tools. Orthogonal dry cutting tests on 6061 aluminum alloy tubes were carried out with the textured and conventional tools (CT). The effect of the texture geometry on the cutting performance was assessed in terms of cutting forces, friction coefficient, chip compression ratio, shear angle, tool adhesions, chip morphology, and machined surface quality. The results show that the textured tools can improve the cutting performance at low cutting speeds, and that the tool with rectangular type of textures is the most effective.


Author(s):  
Toshiaki Segawa ◽  
Hiroyuki Sasahara ◽  
Masaomi Tsutsumi

We have developed a new tool that is called as the “Compressive Residual Stress Generating cutter” (CRSG cutter)[1]. The CRSG cutter can generate effective compressive residual stress within the machined surface concurrently with the milling process. It is expected to improve mechanical properties such as the fatigue life and the resistance to stress corrosion cracking. The purpose of this study is to investigate the possibility of controlling the residual stress state within the machined surface with varying the machining conditions using the CRSG cutter. It was shown that the quantity of the plastic deformation of the machined surface affects the residual stress. The setting of the machining conditions with the CRSG cutter can control the plastic deformation quantity. The cross feed width can change plastic deformation on the machined surface that is the key factor in order to control the residual stress within the machined surface.


Author(s):  
Heping Wang ◽  
Shenfeng Wu ◽  
Xueping Zhang ◽  
C. Richard Liu

To analyze AISI 52100 steel response in hard turning under pre-stressed conditions, an explicit dynamic thermo-mechanical finite element model (FEM) has been developed. The FEM adopts Johnson-Cook constitutive model to describe the workpiece material property; and Johnson-Cook failure model as chip separation criterion; a modified coulomb’s friction law determines the friction behavior at the tool/chip interface. 500MPa of tensile and compressive pre-stress are imposed on the workpiece to simulate the pre-tension-stress and pre-compression-stress conditions respectively in hard turning. The effect of pre-stress on hard turning is determined by analyzing and comparing the simulation results under the three different pr-stress conditions, in terms of saw-tooth chip morphology, cutting forces, plastic strain distribution and temperature distribution on chip, plastic strain distribution and temperature distribution in machined surface, and especially the residual stress in machined surface. It identifies hard cutting under pretension-stress condition is an effective approach to generate a beneficial compressive residual stress profile in hard turning characterized by a bigger value of compressive residual stress and a deeper penetration depth into the hard turned surface which are helpful to enhance the fatigue life of machined components.


2012 ◽  
Vol 591-593 ◽  
pp. 766-770 ◽  
Author(s):  
Rui Tao Peng ◽  
Fang Lu ◽  
Xin Zi Tang ◽  
Yuan Qiang Tan

In order to reveal the adjustment principle of prestressed cutting on the residual stress of hardened bearing steel GCr15, a three-dimensional thermal elastic-viscoplastic finite element model was developed using an Arbitrary Lagrangian Eulerian (ALE) formulation. Several key simulation techniques including the material constitutive model, constitutive damage law and contact with friction were discussed, simulation of chip formation during prestressed cutting was successfully conducted. At the prestresses of 0 MPa, 341 MPa and 568 MPa, distributions of residual stress on machined surface were simulated and experimentally verified. The results indicated that residual compressive stress on machined surface were achieved and actively adjusted by utilizing the prestressed cutting method; meanwhile, within the elastic limit of bearing steel material, the higher applied prestress leads to the more prominent compressive residual stress in the surface layer and subsequently the higher fatigue resistance of the part.


Author(s):  
Mithun K. Dey ◽  
Dave Kim ◽  
Hua Tan

Abstract Residual Stress distribution and parametric influence of friction are studied for the split sleeve cold expanded holes in Al 2024 T351 alloy, by developing a three-dimensional finite element model of the process. Fastener holes in the alloy are necessary for the manufacturing process, but they create a potential area for stress concentration, which eventually leads to fatigue under cyclic loading. Beneficial compressive residual stress distribution as a result of the split sleeve cold expansion process provides retardation against crack initiation and propagation at the critical zones near hole edges. In this parametric study, the influence of friction between contact surfaces of the split sleeve and mandrel is numerically investigated. Hole reaming process after split sleeve cold expansion is often not discussed. Without this post-processing procedure, split sleeve cold expansion is incomplete in practice, and its purpose of providing better fatigue performance is invalidated. This study presents results and an overview of the significance of friction with the consideration of the postprocessing of split sleeve cold expansion. The numerical results show that with increasing friction coefficient, compressive residual stress reduces significantly at the mandrel entry side, which makes the hole edge more vulnerable to fatigue. The different aspects of finite element modeling approaches are also discussed to present the accuracy of the prediction. Experimental residual stress observation or visual validation is expensive and time-consuming. So better numerical prediction with the transparency of the analysis design can provide critical information on the process.


Author(s):  
J. Ma ◽  
Nick H. Duong ◽  
Shuting Lei

This paper investigates the performance of microbump textured cutting tool in dry orthogonal machining of mild steel (AISI 1045 steel) using AdvantEdge finite element simulation. Microbumps are designed on the rake face of cemented carbide (WC/Co) cutting inserts. The purpose is to examine the effect of microbump textured tools on machining performance and to compare it with non-textured regular cutting tools. Specifically, the following microbump parameters are examined: microbump width, microbump height, and edge distance (the distance from cutting edge to the first microbump). Their effects are assessed in terms of the main force, thrust force, and chip-tool contact length. It is found that microbump textured cutting tools generate lower cutting force and thrust force and consequently lower the energy consumption for machining. The micobump width, microbump height, and edge distance all have influence on cutting force in their own ways.


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