Coated Carbide End Mills Research Articles

Tooth Contact Analysis and Manufacture on Multitasking Machine of Large-Sized Straight Bevel Gears With Equi-Depth Teeth

Straight bevel gears are widely used in the plant of large-sized power generation when the gears have large size. The purpose of this study is to manufacture the large-sized straight bevel gears with equi-depth teeth on a multitasking machine. The manufacturing method has the advantages of arbitrary modification of the tooth surface and machining of the part without the tooth surface. For this study, first, the mathematical model of straight bevel gears by complementary crown gears considering manufacture on multitasking machine is proposed, and the tooth contact pattern and transmission errors of these straight bevel gears with modified tooth surfaces are analyzed in order to clarify the meshing and contact of these gears. Next, the numerical coordinates on the tooth surfaces of the bevel gears are calculated and the tooth profiles are modeled using a 3D-Computer-Aided Design (CAD) system. Five-axis control machines were utilized. The gear-work was machined by a swarf cutting using a coated carbide end mill. After rough cutting, the gear-work was heat-treated, and it was finished based on a Computer-Aided Manufacturing (CAM) process through the calculated numerical coordinates. The pinion was also machined similarly. The real tooth surfaces were measured using a coordinate measuring machine and the tooth flank form errors were detected using the measured coordinates. As a result, the obtained tooth flank form errors were small. In addition, the tooth contact pattern of the manufactured large-sized straight bevel gears was compared with those of tooth contact analysis. The data showed good agreement.

High Speed Machining of AISI 52100 Steel

This paper gives the details of High Speed Milling experiments with AISI 52100 steel (HRC52) by using coated carbide end mills. Cutting force and Surface roughness data are presented. The effects of cutting speeds (1000-8000rpm), widths of cut (0.05-0.4mm) and cutting conditions (dry cutting and dry cutting with air coolant) are investigated. The results show that in high speed milling of hardened steels, when cutting speed surpasses a critical value, cutting forces decrease as cutting speed increasing; and the increasing of widths of cut causes the increase of cutting forces approximately linearly; surface roughness does not experience obvious increase or decrease and has a minimum in a specific condition; the machining results of dry cutting with air.

Laser-Assisted Milling of Silicon Nitride Ceramics and Inconel 718

Laser-assisted machining (LAM) has shown its potential to significantly reduce fabrication costs and improve product quality for advanced materials. While extensive studies have been conducted on laser-assisted turning of various ceramics and high temperature alloys, few attempts have been made to extend LAM to milling operations. In this paper, a transient, three-dimensional thermal model developed for laser-assisted milling (LAML) is presented and its accuracy is verified by surface temperature measurements with an infrared camera. LAML experiments designed by the model are successfully conducted on silicon nitride ceramics using TiAlN coated carbide end mills and Inconel 718 using SiC reinforced alumina cutting tools. The promising experimental results, including good surface roughness and acceptable tool wear, show the validation of applying the thermal model to design LAML processes and the feasibility of employing LAML for difficult-to-machine materials such as advanced ceramics and superalloys.

Experimental study of surface integrity during end milling of Al/SiC particulate metal–matrix composites

Abstract The quality of the components produced during end milling of Al/SiC particulate metal–matrix composites (PMMCs) is important as it influences the performance of the finished part to great extent. Hence, the estimation of surface integrity can cater to the requirements of performance evaluation. Therefore, an understanding of surface integrity provides many opportunities to avoid failures, enhance component integrity and reduce overall costs. This paper presents the results of an experimental research on end milling of Al/SiC PMMC. The aim of the investigation is to enhance the knowledge about the machinability of Al alloy reinforced with SiC using TiAlN coated carbide end mill cutters. Investigations on surface quality and the extent of sub-surface damage of machined Al/SiC PMMC and Al alloy were carried out at different levels of cutting conditions. The comparison of Al/SiC PMMC and Al alloy on the basis of surface integrity (surface roughness, residual stress, microstructure and microhardness) was tried out in order to know the machinability of two materials. The results show that the presence of the reinforcement enhances the machinability in terms of both surface roughness and lower tendency to clog the cutting tool, when compared to a non-reinforced Al alloy. The results would serve to understand the end milling machining process better; provide inputs that can ensure better machining of Al/SiC PMMC and thus expected to lead technological and economical gains with the use of Al/SiC PMMC in various industrial applications by replacing Al alloys.

In-process surface roughness prediction using displacement signals from spindle motion

A method to predict surface roughness in real time was proposed and its effectiveness was proved through experiment in this paper. To implement the proposed method in machining process, a sensor system to measure relative displacement caused by the cutting operation was developed. In this research, roughness of machined surface was assumed to be generated by the relative motion between tool and workpiece and the geometric factors of a tool. The relative motion caused by the machining process could be measured in process using a cylindrical capacitive displacement sensor (CCDS). The CCDS was installed at the quill of a spindle and the sensing was not disturbed by the cutting. The workpiece was NAK80 and TiAlN coated carbide end mills were used in the test. Model to predict surface roughness was developed. A simple linear regression model was developed to predict surface roughness using the measured signals of relative motion. Close relation between machined surface roughness and roughness predicted using the measured signals was verified with similarity of about 95%.

Properties and cutting performance of (Ti,V)N coatings prepared by cathodic arc ion plating

(Ti,V)N coatings were deposited on WC–Co substrates using the cathodic arc ion plating method. The structures and compositions were characterized by X-ray diffraction, transmission electron microscopy, and electron probe microanalysis. The (Ti,V)N coating showed a single phase cubic B1 structure with a dense columnar microstructure typical of cathodic arc ion plating. The wear-resistant properties and friction coefficients of (Ti,V)N coatings against steel were evaluated using the ball-on-disc test at elevated temperatures. (Ti,V)N had a friction coefficient of 0.51 against carbon steel at 600 °C, which is lower than the 0.91 friction coefficient of (Ti,Al)N. High-speed cutting performance was investigated using coated carbide endmills. (Ti,V)N coatings showed greatly improved cutting performances on low hardness carbon steels. The wear mechanism and cutting characteristics are discussed in terms of the structure and properties of the films.

Performance Improvement of End Milling Using Graphite as a Solid Lubricant

ABSTRACT In any machining operation, the use of coolants is essential to dissipate heat generated during machining and hence to improve productivity, machinability, etc. However, the use of cutting fluids in machining operations may seriously degrade the quality of environment. New cutting techniques are to be investigated to alleviate the problems associated with wet machining. To overcome some of the problems, an attempt has been made to use graphite as a solid lubricant. This paper deals with an investigation on using graphite as a solid lubricant to reduce the heat generated at the milling zone. An experimental setup has been developed to direct graphite powder continuously onto the workpiece and tool interface at the required flow rate. Experimental studies have been conducted to see the effect of tool geometry (radial rake angle and nose radius) and cutting conditions (cutting speed and feed rate) on the machining responses such as cutting forces, specific energy, and surface finish in solid lubricant assisted machining using four fluted solid coated carbide end mill cutters. Results indicate that there is a considerable improvement in the performance of milling AISI 1045 steel using graphite as a solid lubricant when compared with machining using cutting fluids in terms of specific energy requirements, cutting force, and surface finish.

A GENETIC ALGORITHMIC APPROACH FOR OPTIMIZATION OF SURFACE ROUGHNESS PREDICTION MODEL IN DRY MILLING

ABSTRACT Majority of machining operations require the cooling and lubricating action of cutting fluids. But, due to ecological and human health problems, manufacturing industries are now being forced to implement strategies to reduce the amount of cutting fluids used in their production lines. In the present work, experimental studies have been conducted to see the effect of tool geometry (radial rake angle and nose radius) and cutting conditions (cutting speed and feed rate) on the machining performance in dry milling with four fluted solid TiAlN coated carbide end mill cutters. The significance of process parameters on surface finish has been evaluated using analysis of variance. Mathematical models have been developed for surface roughness prediction using Response Surface Methodology. Then the optimization has been carried out with Genetic Algorithms using the surface roughness models developed and validated in this work. This methodology helps to obtain the best possible tool geometry and cutting conditions for dry milling.

Structure and properties of Al–Ti–Si–N coatings prepared by the cathodic arc ion plating method for high speed cutting applications

Al–Ti–Si–N coatings with several Al/Ti/Si ratios were deposited on WC–Co substrates by the cathodic arc ion plating method. Microstructure and compositions of the local parts of the films were investigated by using transmission electron microscopy with EDS. The films seemed to have the same columnar structure as (Al,Ti)N films but with a smaller column size. The crystal structure, hardness and oxidation resistance were investigated, and Al–Ti–Si–N films with cubic B1 crystal structures had higher hardness than (Al,Ti)N films. Similarly, the Al–Ti–Si–N films displayed greatly improved oxidation resistance at elevated temperatures of up to 1100°C in air. The cutting performances of (Al,Ti,Si)N coated carbide endmills were evaluated and offered significantly better performance in the machining of hardened steels with higher cutting speeds. The wear mechanism and cutting characteristics are discussed along with the film properties.

Machinability Experiments and Economical Considerations of Dry Machining. 2nd Report. End Milling and Drilling of Medium Carbon and Alloy Steels.

This paper deals with the elimination of water-based cutting fluid based on machinability tests and economical considerations when plain medium carbon steels and an alloy steel are machined with a coated carbide end mill or a carbide drill. In end milling, no remarkable difference between dry and wet machining is recognized in terms of chip disposability, machining accuracy, cutting force, tool life and production cost. Besides, dry machining yields a low production cost at low cutting speeds of less than 90 m/min for S 45 C steel and 20 m/min for SKD 61. In drilling, dry machining is not as good as wet machining with respect to machinability, but the cost analysis shows that dry machining is preferable at low cutting feeds of less than 200 mm/min for S 50 C steel. From an environmental point of view we should take a positive attitude to introduce dry machining as far as its advantages on machinability and economics are recognized.