Applied Mechanics and Materials Vol. 657

Abstract: Based on the experimental research and of theoretical studies in the paper it is presented recommendations and possibilities for the multicriteria optimization of the machining processes. For the application, it is analyzed in this way, the case of the turning process, in special the operation of roughness. The results of the research are analyzed, in special, with the help of suggestive graphs, based on it is presented recommendations for the optimizations of the design and technological process for the machining production from energy consumption, costs and productivity point of view.

Abstract: Machining of Complex Concave or Convex Surfaces Requires the Use of Ball End Milling Cutters. Obtaining the Expected Surface Quality Compete Various Technological Factors which should be Taken into Account. Following the Machining of the Surface with Different Inclination Angles between the Cutting Tool Axes and the Machined Surface, Significant Changes of the Surface Roughness have been Observed. Based on the Tests Performed, we can Determine the Range of the Tool Inclination Angle, which is the Best for the Surface Quality. we have also Made a Correlation between the Cutting Speeds, Inclination Angle of the Cutting Tool Toward the Machined Surface for an Obtained Surface Quality. the Presented Results are Based on Experimental Research in Industrial Conditions by Using CNC Machine Tools with 5 Axes. the Tests have been Performed on the C45 Material, Heat Treated to 34HRC.

Abstract: In the technical literature there are some studies which use measured signals in order to compensate the errors caused by vibrations [1, 2], by the cutting force [3], by the deflections of the technological system [4], and others. Also, the technical literature presents some studies [6, which give few measurement techniques in order to measure the error which appears into the turning process and also, some methods to compensate or eliminate the consequences produced by those errors. In such conditions, this study propose to establish a possible methodology that can make the measurement of the radial deviation which corresponds to a work piece obtained into a turning process. The novelty of this study comes from the method of measurement used and from the measurement stand which provide the values of the radial deflection for the processed work piece, during the process. The experimental procedure assumes the existence of an experimental stand which allows to measure the distance between a sensor and the considered work piece. In such conditions, the mathematical algorithms used will transform the received electrical signal into a physical displacement. The obtained results suggest that the signal provided by the experimental stand and which it is used for measure the distance between a sensor and the considered work piece, allows to establish, with accuracy, the values for the radial deviations of the work piece. Also, this fact can offer a graphical representation of the shape which corresponds to the real profile of the processed work piece.

Abstract: The Method of Estimation of Possibilities of the Machining Productivity Rise Taking into Account the Action of Cutting Fluid (TCF) and Coated Carbide Cutting Tools (CCT) for Rough and Fin-Ish Turning Corrosion-Proof, Heat Resisting and Stainless Steels and Alloys is Perfected. the Factor of Machining Productivity Rise at the Expense of Use TCF and CCT is Set. it is Executed Theoretical and Experimental Researches of Influence of the Cutting Regimes on the Cutting Temperature and the Ma-Chined Surface Roughness at Turning of Different Hard-Processing Steels and Alloys. Dependences of the Cutting Temperature and the Machined Surface Roughness on Cutting Speed, Feed and Depth Taking into Account the Action of TCF and CCT are Set. the Factors of Decline of the Machined Surface Roughness and the Cutting Temperature are Certain at the Use of TCF with Different Cooling and Lubri-Cant Properties. the Factors of Machining Productivity Rise are Certain under Various Conditions of the Rough and Finish Turning Different Corrosion - Proof, Heat Resisting and High - Resistance Steels and Alloys Depending on the Factor of the Cutting Temperature Decline and Factor of the Tool Life Rise. the Set Factor of Machining Productivity Rise Allows Estimating Efficiency of the Use of Various TCF and CCT for Different Hard-Processing Materials.

Abstract: The paper consists of a research in designing and experimental analysis using a face milling cutter with round inserts. A general model for the new cutter is proposed taking into consideration multiple aspects regarding monitoring and controling the milling process. A comparison of measured vibrations when cutting with different parameters for two constructions of the milling head is presented. The objective of this vibration comparison is to verify wether the new design behaves in similar way with the classic and proven concept of insert clamping using a central screw.

Abstract: The work is dedicated to investigation of the particulars of stressed-deformed state of fine disc tool with internal cutting section under conditions of its pre-stressing. It was suggested for reduction of tools oscillations at cutting to apply pre-stressing of the tools disc by means of controlling elements. The elements, which control the elements stress allowed to eliminate self-oscillations and resonance oscillations of the tool at high-speed materials cutting. In the paper the problem of evaluation of stress and deformed state of fine disc cutting tools with application of the method of finite elements (FEM) was solved. The article also contains epures of tangential stresses inside the internal contour of disc tools. On the basis of the investigations performed the synthesis for design of the main elements of fine disc tools with inner cutting section was carried out. The performed investigation was aimed at improving of the quality and stability of cutting with fine disc tools under conditions of high-velocity cutting and in presence of a dynamic component of the cutting process, ensuring improvement in durability and productivity of the tool.

Abstract: One of the most important parameters used in the evaluation of machining technological systems is the dynamic quality, represented by the system stability and the specific feature of the reaction to the external factors, during the machining process. The dynamic quality of the machining system is given by the dynamic quality of the machine tool, cutting tool, cutting tool holding device, workpiece fixture. The dynamic behavior of the machining system is given by the behavior of the elastic subsystem of the workpiece and tool. In the case that the deformation of the machine tool is negligible in relation with the two subcomponents of the technological system, mentioned, these can be studied separately. It is important to determine which is the weakest link of the technological system or to determine which is the component that can lead to the loss of the stability of the entire system. In the paper it is studied the dynamic behavior of the turned long, flexible workpieces. The workpieces are clamped in the lathes chuck and in the tailstock. The natural vibrational frequencies are determined according to a series of parameters as the diameter of the workpieces, axial forces applied by the tailstock.

Abstract: The performance of a high speed milling process of hardened tool steel depends on various machining conditions which affect the surface quality achieved on the component, the cutting force involved, the mechanism of chip formation, etc. The paper propose is to experimental investigate the cutting forces involved in the machining of a difficult-to-cut material, AISI W1 steel of different hardness states.

Abstract: In the laboratory of cutting machining technologies from the “Gheorghe Asachi” Technical University of Iaşi, a series of investigations on the machinability of cast iron samples having various structures were designed and developed. The aim of the research was to know and to explain the way in which various constituents of some iron castings exert influence on the degree of wear of a milling tool made of high speed steel. Within this research, mathematical empirical models were determined, in order to calculate the cutting speed v₆₀, considered as an indicator for the evaluation of machinability. The research allowed establishing the factors able to have a major influence on tool wear phenomenon and obtaining thus a more complete image concerning the machinability of grey iron used for castings.

Abstract: The ball nose end mills are highly used for complex sculptured surfaces in 3-5 axes milling. The modeling of the cutting process using ball nose end mills is more complex than in the case of simple end mills due to the fact that the cutting speed varies continuously along the cutting edge. By tilting the cutting tool relative to the surface to be machined, the modeling is getting more complicated due to the large number of input variables. This paper presents a review of the main modeling types, underlining the specificity, the advantages and disadvantages for each type in comparison to an own research on a parametric CAD model. There are also recommendations made towards the modeling process, based on the results obtained by the authors.