In this study, the effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and resultant forces in the finish hard turning of AISI H13 steel were ...experimentally investigated. Cubic boron nitrite inserts with two distinct edge preparations and through-hardened AISI H13 steel bars were used. Four-factor (hardness, edge geometry, feed rate and cutting speed) two-level fractional experiments were conducted and statistical analysis of variance was performed. During hard turning experiments, three components of tool forces and roughness of the machined surface were measured. This study shows that the effects of workpiece hardness, cutting edge geometry, feed rate and cutting speed on surface roughness are statistically significant. The effects of two-factor interactions of the edge geometry and the workpiece hardness, the edge geometry and the feed rate, and the cutting speed and feed rate also appeared to be important. Especially honed edge geometry and lower workpiece surface hardness resulted in better surface roughness. Cutting-edge geometry, workpiece hardness and cutting speed are found to be affecting force components. The lower workpiece surface hardness and honed edge geometry resulted in lower tangential and radial forces.
For the critical aero-engine parts it’s important to understand influence of cutting tools, cutting parameters, tool ware etc. on near surface condition which highly affect fatigue strength and at ...the same part life-time. New material implemented for the latest designs of aero-engines parts generate challenges for machining processes to fulfil strict requirements of aviation standards. Finish machining is the most important stage of process influencing fatigue strength. cBN tool are often used for final stage of machining. The objective of this study was analysis of cutting mechanics during finish turning of modern nickel-cobalt based alloy with cBN insert. Observations of cutting tool wear and cutting parameters influence on the components of cutting force, surface roughness and residual stress are presented in this paper.
•AFM imaging and reconstruction algorithm are presented.•Measuring method to eliminate the dilation effect of AFM probe tip is presented.•Dilation effect of AFM probe tip on the diamond tool ...measurement is important.•The profile touched by the probe tip can be reconstructed perfectly.
Measurement of diamond cutting edge is of great importance in ultra-precision machining. Atomic force microscope (AFM) that takes advantage of its three-dimensional (3D) imaging in nanoscale becomes an indispensable means to acquire the 3D surface morphology of the diamond tool cutting edge. However, the dilation induced by AFM probe tip in diamond tool cutting edge measurement is a key error source in cutting edge evaluation, especially for the very sharp edge. In this paper, analysis and elimination method of this dilation effect are presented based on the principle of AFM imaging in terms of mathematical morphology theory. Our work effectively improves the evaluation accuracy of diamond tool cutting edge, which is beneficial to the diamond tool manufacture and selection in ultra-precision machining.
5-axis machining operations bring new challenges for predicting cutting forces. Complex tool workpiece engagements and tool orientations make it difficult to adapt 3-axis process models for 5-axis ...operations. A new model is developed to predict cutting forces with arbitrary tool/workpiece engagement and tool feed direction. A discretization approach is used, in which the tool is composed of multiple cutting elements. Each element is processed to determine its effect on cutting forces, and global forces are determined by combining the elemental effects. Cutting tests are conducted to verify force predictions, where the tool/workpiece engagement is provided through a geometric software application.
Machinability of engineering materials is crucial for industrial manufacturing processes since it affects all the essential aspects involved, e.g. workload, resources, surface integrity and part ...quality. Two basic machinability parameters are the surface roughness, closely associated with the functional and tribological performance of components, and the cutting forces acting on the tool. Knowledge of the cutting forces is needed for estimation of power requirements and for the design of machine tool elements, tool-holders and fixtures, adequately rigid and free from vibration. This work investigates the influence of cutting conditions on machinability indicators such as the main cutting force Fc and surface roughness parameters Ra and Rt when longitudinally turning CuZn39Pb3 brass alloy. Full quadratic regression models were developed to correlate the machining conditions with the imparted machinability characteristics. Further on, an advanced artificial grey wolf optimization algorithm was implemented to optimize the aforementioned responses with great success in finding the final optimal values of the turning parameters.
This paper presents the results of experimental work in dry turning of austenitic stainless steels (AISI 304 and AISI 316) using CVD multi-layer coated cemented carbide tools. The turning tests were ...conducted at four different cutting speeds (120, 150, 180 and 210
m/min) while feed rate and depth of cut were kept constant at 0.16
mm/rev and 1
mm, respectively. The cutting tools used were TiC/TiCN/TiN and TiCN/TiC/Al
2O
3 coated cementide carbides. The influences of cutting speed, cutting tool coating top layer and workpiece material were investigated on the machined surface roughness and the cutting forces. The worn parts of the cutting tools were also examined under scanning electron microscope (SEM). The results showed that cutting speed significantly affected the machined surface roughness values. With increasing cutting speed, the surface roughness values decreased until a minimum value is reached beyond which they increased.
This paper explores the effect of tool wear and surface roughness during the CNC turning of D2 steel by using acoustic emission and force sensors. The values of the forces were measured by using a ...Kistler 9257B dynamometer while the acoustic emission sensor was fixed upon the tool shank. The machining process was carried out until the flank wear was found to approach the critical value of 0.3mm. Tool wear plays a decisive role in any machining process since it contrarily affects tool life and forces. This has a direct impact on surface quality of the machined surface. Therefore, methods for sensing cutting tool wear are crucial in view of optimum use of cutting tools with effective monitoring system. As the wear increases, the radial forces and the surface roughness were found to shoot up considerably. The acoustic emission was analyzed and parameters were found to increase proportionally with tool wear.
Abstract
When considering the environmental issues in machining, the fundamental concern is the use of cutting fluids. Industry and research institutions are looking for ways to reduce the use of ...cutting fluids for ecological and economical reasons. The disposal of used cutting fluid poses problems to the environment. This has forced engineers to come up with modern ways of cooling technologies during machining.
This paper reports on the experimental investigations carried out under dry, minimum quantity of lubricant (MQL), and flood(fully)-lubricated conditions during drilling of aluminium (AA1050). The experiments were planned based on orthogonal arrays, made with prefixed cutting parameters (f and Vc) and different lubricated conditions. An analysis of variance (ANOVA) was carried out to check the validity of the proposed parameters and also their percentage contributions. The results of the tests show that with a proper selection of the range of cutting parameters, it is possible to obtain performances similar to flood-lubricated conditions by using MQL.
Although brasses are essentially copper and zinc alloys, they also contain other alloying elements such as lead, silicon, aluminium, iron, tin, manganese, nickel or arsenic whose presence and content ...are responsible for the wide variety of properties inherent to these materials.
In this article, the effect of the chemical composition of brasses, considering each alloying element and the effective copper content, upon the machinability has been investigated.
For that purpose, machinability tests have been carried out on a CNC lathe under lubricated conditions. The study includes both commercial alloys and samples prepared in laboratory. The experimental procedure consists on turning operations, during which cutting forces and surface roughness obtained in brass workpieces are measured. The chip class is accordingly evaluated.
The statistic treatment of the results enables the establishment of correlations between the studied machinability parameters and the chemical composition of different kinds of brasses.
A wear of cutting tools during machining process is unavoidable due to the presence of frictional forces during removing process of unwanted material of workpiece. It is unavoidable but can be ...controlled at slower rate if the cutting speed is fixed at certain point in order to achieve optimum cutting conditions. The wear of cutting tools is closely related with the thermal deformations that occurred between the frictional contact point of cutting edge of cutting tool and workpiece. This research paper is focused on determinations of relationship among cutting temperature, cutting speed, cutting forces and radial depth of cutting parameters. The cutting temperature is determined by using the Indium Arsenide (InAs) and Indium Antimonide (InSb) photocells to measure infrared radiation that are emitted from cutting tools and cutting forces is determined by using dynamometer. The high speed machining process is done by end milling the outer surface of carbon steel. The signal from the photocell is digitally visualized in the digital oscilloscope. Based on the results, the cutting temperature increased as the radial depth and cutting speed increased. The cutting forces increased when radial depth increased but decreased when cutting speed is increased. The setup for calibration and discussion of the experiment will be explained in this paper.
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