Papers by Keyword: Tool Wear

Abstract: Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process.Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at v_c 105 m/min, f 0.3 mm/rev and a_p 1 mm where the regular insert had a catastrophic failure at v_c 90 m/min, f 0.1 mm/rev and a_p 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.

Abstract: Titanium alloy is becoming increasingly employed in the aerospace industries due to its good mechanical and chemical properties. As a typical difficult-to-machine material, there are problems of fast tool wear and poor stability of the processing quality in the machining process. Therefore, experiments of high feed milling of TB2 titanium alloy in liquid nitrogen cooling were carried out to measure the cutting force and the cutting temperature. The experimental results showed that under some parameters, liquid nitrogen could decrease the cutting force and cutting temperature in comparison with dry cutting. What’s more, the tool life as well as the surface quality was improved.

Abstract: Recently the demands for miniature component of varying materials have been rapidly increasing in aerospace industry. Carbon fiber reinforced plastics is widely used as functional or structural material due to its superior material properties. It also is one of the difficult to machine materials because of the poor machinability. This paper presents an experimental study on micro milling of carbon fiber reinforced plastics with self-developed polycrystalline diamond tool. Cutting force and specific cutting energy are analyzed. The minimum chip thickness and carbon fiber diameter are found to have great effect on the cutting force signature peak. Tool wear mechanism of polycrystalline diamond tool also is investigated.

Abstract: In order to achieve the high efficiency machining of titanium, the cutting force model is verified through the cutting experimental platform in machining cant and curved surface with ball end milling. And then the influence of cutting parameters and surface curvature on cutting force and tool wear are investigated. Finally, the prediction model of tool wear is established based on the orthogonal test and the least square method. This study proposes that the tool wear and each tooth feeding have a major impact on cutting force and that the convex surface from a small curvature to larger and the concave surface from a large curvature to smaller can effectively improve the life of tool in machining curved surface.

Abstract: Titanium alloy Ti6Al4V has poor machinability, which leads to high unit cutting force and cutting temperature, rapid tool failure. In this study, the effect of the cutting speed, feed rate and cooling condition on cutting force and cutting temperature is critically analysed by turning experiment. At the same time, the relationship is established among tool wear, cutting force and cutting temperature. This investigation has shown that cutting speed is the decisive factor which increasing cutting force and cutting temperature. In the process of turning, tool wear results in high amounts of heat and mechanical stress, which leads to serious tool wear. The Minimal Quantity Lubrication reduces the frictional condition at the chip-tool, decreases cutting force and cutting temperature, and delays the tool failure.

Abstract: In high speed machining superalloys processes, tool wear is strongly influenced by the cutting temperature and contact stresses. Finite element analysis of machining can be used as a supplementary to the physical experiment, this paper provides investigations in 2D and 3D finite element modeling and simulation of prestressed cutting for GH4169 superalloy, a tool wear model for the specified tool and workpiece pair is developed based on the Usui's wear model, furthermore, tool temperature, wear rate and nodal displacement on the face of tool in prestressed cutting of superalloy is analyzed under various prestress condition and cutting parameters, and Python language is adopted to modify the Abaqus code used to allow tool wear calculation and tool geometry updating. The results of the simulation indicate that the tool wear rate increases with the increase of cutting time, and the influence of the prestress to tool wear in prestressed cutting process of shaft part is unremarkable.

Abstract: Tool wear is easy occurred in titanium alloy milling process which will affect the surface quality. Surface roughness and surface morphology as an important index to describe and evaluate the surface quality has a great influence on service performance. Therefore, the study on the effect of tool wear on surface qualities is important to improve the surface integrity of titanium alloy parts. Cutting radius of ball-end milling cutter is solved to analyze the effect of tool wear on the cutting radius. The tool wear and the surface qualities of TC4 are achieved through wear experiment. And then the influence law of tool wear on surface qualities and chip morphology are analyzed. The results show that surface roughness value decrease firstly and then increases and that chip morphology with flank wear increase from the unit chip to the serrated chip.

Abstract: This paper proposes the prediction of cutting temperature, tool wear and metal removal rate using fuzzy and regression modeling techniques for the hard milling process. The feed per tooth, radial depth of cut, axial depth of cut and cutting speed were used as process state variables.The experiements were conducted using RSM based central composite rotatable design methodology. Regression and fuzzy modeling were used to evaluate the input – output relationship in the process. It is interesting to observe that the R² and average error values for each response are very consistent with small variations were obtained.Also, the confirmation results show that very less relative error varitions. Thus, the developed fuzzy models directly integrated in manufacturing systems to reduce the more computational complexity in the process planning activities.

Abstract: In metal cutting, increasing cutting spped and feed achieve higher productivity, but it will affect dimensional accuracy and surface integrity of the work surface, wear resistance and life of tool. Cutting fluids when appropriately chosen and applied will minimize these problems. This work deals with the optimization of process parameters in turning of EN24 and SS316L Steels with different cutting fluids with different cutting inserts under different machining conditions using Taguchi’s Robust Design Methodology. The control factors selected are machining environment, cutting speed, feed, depth of cut, work piece material and type of tool. Investigations are carried out on conventional lathe using the prefixed cutting conditions. Tool Wear and Surface Roughness are measured and anlysed using ANOVA and appropriate conclusions are derived.

Abstract: Machining hard to machine materials using conventional method of machining has proved to be very costly as these materials greatly affect the tool life because of poor machinability. One material that requires considerable study is Titanium which is a relatively lightweight material and provides excellent mechanical properties. The major problems in machining Titanium Alloys are the high cutting temperatures and rapid tool wear. Machining of Titanium using techniques like Laser Assisted Machining and Plasma Assisted Machining have proven to give high productivity rates, but the costs associated are very high. The main objective of this work is to develop a method for improving the machinability of Ti-6Al-4V using Work Piece Pre-Heating technique by using Conventional Machining with standard tools. Design of experiments was performed using Taguchi’s robust design. The machining operation was performed at elevated temperatures using oxy-acetylene flame. The tools used are Coated and Uncoated Carbide Tools. Based on the tool wear values obtained with different cutting conditions, it is concluded that this technique is feasible with the coated and uncoated carbide tools to machine titanium components commercially.