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.
When the removal depth in micro milling is downsized, the effect of the crystal grain in material becomes relatively large. The crystal grain in materials, therefore, should be downsized to achieve ...high qualities and high reliabilities of the micro devices. The study discusses the effect of the crystal grain size on the surface finish, burr formation and the affected layer in micro milling of stainless steel. The crystal grains are reduced to an average size of 1.5μm by repetition of material forming and phase transformation. The milling tests were performed to measure the cutting forces, the surface finishes, the burr shapes and the thicknesses of the affected layers. The force component ratio of the fine grained steel is higher than that of the standard steel. The shearing force decreases in cutting of the fine grained steel; meanwhile, the friction and/or the indentation forces increase. Burr formation is reduced when the crystal grain size is small. In cutting of the standard steel, X component in the cutting force suddenly drops near the end of the groove and a large burr is formed on the edge of the groove. The affected layer largely depends on the crystal grain size. The thickness of the affected layer remarkable decreases in milling of the fine grained steel.
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.
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.
•Classification test results of the condition of tool blades on a multi-tool head were presented.•Signals of the mining power by sharp and blunt mining tools were recorded.•The observed data were ...transformed into the probability density functions for two groups of ripping tools.•The probability density functions differ in almost all tested power ranges.
In the article, the ripping tools wear in the process of concrete cutting is investigated. Data were observed as signals of mining power of sharp and blunt tools. Using nonparametric estimates combined with the recent approach of a functional data analysis, it is possible to statistically distinguish between the two knife states in terms of their wear.
An analytical model of rotary ultrasonic milling Bertsche, Erich; Ehmann, Kornel; Malukhin, Kostyantyn
International journal of advanced manufacturing technology,
04/2013, Letnik:
65, Številka:
9-12
Journal Article
Recenzirano
Rotary ultrasonic machining is currently being used as a manufacturing method for advanced ceramic materials, but its complexity has hindered its acceptance in industry. For this technology to gain ...wider acceptance, it must first be scientifically better understood. The majority of published rotary ultrasonic machining (RUM) papers studied the effect of RUM process parameters on machining performance and removal mechanisms for drilling of circular holes. In industries such as aerospace, the production of advanced turbine components requires machining of complex 3D features using milling strategies. The objective of this paper will be to present a new physical model based on rotary ultrasonic milling which will help provide a better scientific understanding of the process. This will be accomplished by first modeling the macro kinematics between the tool and material followed by the modeling of micro kinematics between the individual diamond grains and the material. In addition, a force model for predicting machining process forces will also be introduced and validated based on a set of experiments. The physical models will help determine the relationships between input parameters, cutting parameters, and process output parameters for rotary ultrasonic milling.
PDF
