Papers by Keyword: Tool Wear

Abstract: This paper performed a series of finite element method (FEM) simulation to investigate the influence of the tool wear on the cutting temperature in the diamond ultra-precision cutting of the aluminum alloy mirror. The two-dimensional FEM model including the diamond tool with the different average width of wear land on flank face was established. A series of ultra-precision cutting experiments using different cutting distance was performed. The tool wear was detected by scanning electron microscopy (SEM), and the cutting temperature was detected by infrared thermal imager. The comparison of the simulation investigations and the experimental investigations was done. The results revealed that the cutting temperature increases with an increase of the average width of wear land on flank face in the FEM simulation. And in the ultra-precision cutting experiments the diamond tool wear becomes severe as the cutting distance increases, meanwhile the severe tool wear results in the higher cutting temperature. Consequently the FEM simulations prove to be right.

Abstract: In this paper, ultra-precision cutting experiments were carried out with titanium alloy material Ti-6A1-4V by using single crystalline diamond tools. Experimental results show that the wear patterns of rake face of diamond tools are crater wear and groove wear, the wear patterns of flank face of diamond tools are uniform wear and groove wear, and the wear mechanisms of single crystalline diamond tool are chemical wear and mechanical wear. Graphitization and microcosmic cleavage of the diamond tools occur in the cutting process.

Abstract: The application of Ni-based powder metallurgy superalloys materials was limited for its' difficult-to-machine, such as excessive tool wear, frequent tool change, short tool life, low productivity, and large amount of power consumption etc. So the studying of Ni-based powder metallurgy superalloys drilling process becomes extremely important. This paper mainly introduces the research status of drilling of Ni-based powder metallurgy superalloys materials and through synthesize considering cutting force and cost effective, we determined the optimal of cutting tool materials is carbide YG8 twist drill. The optimal parameters of drilling of Ni-based powder metallurgy superalloys: cutting speed of 15m/min, feed per tooth of 0.02mm/r. When the superalloys material is machined by standard twist drill, it is always appearing the failure modes of drilling.

Abstract: A series of research on the interactions among tool wear, cutting force and cutting vibration were conducted through high speed milling experiment in this paper, which objected the titanium alloy as difficult-to-cut materials. The results showed that the increasing of tool wear led to enlarging the cutting force and cutting vibration; and vice versa, the increasing of cutting force and cutting vibration aggravated the tool wear in the process of machining. Besides, the variation trend of tool wear with cutting was similar to the trend of cutting force, while the variation trend between cutting vibration and tool wear was different. Especially in the sharply cutting tool wear stage, the influence of tool wear on cutting vibration became more complicated.

Abstract: The article deals with the tool life of ball nose end mills and surface roughness of steel C45 depending on up-copying and down-copying. The cemented carbide and high speed steel was used as tool material. Furthermore, the new and sharpened cutting tools were also compared. In the experiment, the cutting speed, feed rate, axial and radial depth of cut were not changed. The results show different achieved surface roughness of machined material C45 and tool life of ball nose end mills depending on the copy milling strategy for various tool materials.

Abstract: Titanium alloys are referred to difficult-to-cut materials because of its some inferior properties like low thermal conductivity and high chemical reactivity. To improve machinability of these alloys one way is to use cutting fluids which removes the heat generated at the chip tool interface during the machining process. But coolant with low pressure and improper delivery is not able to break the vapor barrier created by high cutting temperature. The present work investigates the effect of using high pressure coolant system (50 Bar) on machinability of Ti6Al4V. The machinability was measured in terms of tool wear. The dominant tool wear mechanism was investigated by using scanning electron microscopy and energy dispersive X-ray analysis of worn out cutting tool surfaces. Abrasion wear on flank face and crater wear on the rake face was observed as a dominant tool wear mechanism. Along with this diffusion of titanium from the work surface to tool face is also confirmed.

Abstract: In this paper, contact conditions between cutting tool and work material, strength of cutting tool are analyzed. Experimental and theoretical studies of contact load distribution on the artificial flank wear-land that appears on the cutter in a free orthogonal turning disk of titanium alloy (Ti-6Al-2Mo-2Cr) are described. Calculations of internal stresses by the method of finite elements show that for the sharp cutter the main stresses into cutting wedge near to the cutting edge are compression stresses, very large (10 000 MPa) and exceed ultimate compression stress for cemented carbide. Decreasing of main stress with appearance of wear on the flank explains ability working of cutter even at large wear on the flank. Increasing of cutter’s break off probability with appearance of large wear on the flank is explained by increasing of zone where the internal stresses are large enough (more or equal 3 000 MPa) and increasing of defects probability into this zone, which serves as source of cracks. Abbreviation and symbols: m/s – meter per second (cutting speed v); mm/r – millimeter per revolution (feed rate f); MPa – mega Pascal (specific contact load as stress σ or τ); h_f – the width of the flank wear land (chamfer) of the cutting tool, flank wear land can be natural or artificial like in this paper [mm]; x_h – distance from the cutting edge on the surface of the flank wear land [mm]; σ_h – normal specific contact load on the flank land [MPa]; τ_h – shear (tangential) specific contact load on the flank land [MPa]; HSS – high speed steel (material of cutting tool); P_{y r} – radial component of cutting force on the rake face [N]; P_z – tangential component of cutting force [N]; γ – rake angle of the cutting tool [°]; α – clearance angle of the sharp cutting tool [°]; α_h – clearance angle of the flank wear land [°]; b – width of a machined plate or disk [mm]; σ_-UTS - ultimate compression stress [MPa]; σ_UTS - ultimate tensile stress [MPa].

Abstract: Tool wear measurement has drawn a significant of attention in the past decades. However, no research has been found on the investigation of tool wear measurement in ultra-precision raster milling (UPRM) process since it is a relative complex cutting process. In the present study, tool wear characteristics were identified by using cutting chip morphologies and a groove cutting. Tool wear investigation using cutting chips is effective because diamond tool wear characteristics can be directly imprinted on the cutting chip surface. Through the inspection of chip surfaces, the profile and location of the tool fracture can be identified. Also, through the groove cutting, the cutting edge retreat due to the tool flank wear can be identified. In this research, a mathematical model was established to calculate the tool retreat. The experimental result shows that the proposed tool wear investigation method is an effective method.

Abstract: Recently, high-combustion-efficiency jet engines have become essential in the aircraft industry. High burning temperatures are necessary to maximize the combustion efficiency of jet engines. Inconel 718, which has excellent mechanical and chemical properties, has been selected for use in many jet engine parts. However, it is difficult to cut because of its low thermal conductivity. Consequently, wet cutting is typically used to reduce the heat generated in cutting Inconel 718. In this study, we conducted experiments to examine the relationships between the cutting characteristics and tool fracture in wet cutting.

Abstract: Nickel-based superalloys such as Inconel 718 are known as one of the most difficult-to-cut materials due to their mechanical and chemical properties and the tool life is extremely short. Recently, Cubic-Boron-Nitride (CBN) has received a considerable attention as a material for cutting tools and has been considered to be a major candidate for high performance cutting of Inconel 718. However, the detailed wear behavior of CBN tools in cutting of Inconel 718 is not sufficiently understood yet, and the performances of CBN tools are still insufficient in practical use. To overcome this problem, we first conducted orthogonal cutting experiments on Inconel 718 at low (20 m/min) and high (100 m/min) cutting speeds employing CBN cutting tools to clarify the detailed wear mechanisms. Moreover, relationship between surface microstructures of the cutting tool and wear resistance was investigated. As a result, it was found that a rake face with micro grooves significantly suppressed the crater wear at low cutting speed, although polished surface rake face reduced the initial crater wear by approximately 40 % compared to the non-polished tool in high speed cutting of Inconel 718.