scholarly journals Bases of variational method for calculating of metal-cutting systems accuracy

2018 ◽  
Vol 224 ◽  
pp. 01038
Author(s):  
Olesya Anikeeva ◽  
Alexander Ivakhnenko ◽  
Oleg Erenkov

The bases of a variation method to calculate the metal-cutting systems accuracy for the first time are systemically stated in this paper. The main attention is paid to a problem of joint influence of geometrical accuracy of machine tools and cutting tools parameters on the details processed surfaces accuracy. The general mathematical model of metal-cutting systems accuracy is presented in this work. The general model is the basis to develop the full mathematical model of turning metal-cutting system accuracy. The results of accuracy modeling at turning with a wide cutter are received when studying nature of influence of the lathe and the cutting tool geometrical errors on processing accuracy of cylindrical and face surfaces. The directions of further researches in the field of calculations of metal-cutting systems accuracy at difficult surfaces processing by the shaped cutting tool and also when accounting rigidity of the systems elements and the proceeding processes are revealed in the presented work.

2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.


2018 ◽  
Vol 224 ◽  
pp. 01057
Author(s):  
Viktor I. Guzeev ◽  
Danil Yu. Pimenov

The article presents a new approach to the design of technological processes of processing parts on metal cutting machines in the integrated production conditions based on the expected forecast of the parts processing accuracy. The stages of choosing the parameters of processing steps are combined with determining the parameters of the cutting tool and machining attachments by simulation modeling. The design sequence begins with the first operation.


1997 ◽  
Vol 119 (4) ◽  
pp. 707-717 ◽  
Author(s):  
Milovan Z˘ivanovic´ ◽  
Miomir Vukobratovic´

The procedure of modeling and the complete general form mathematical model of manipulators with six degrees of freedom in cooperative work are presented in the paper, together with the solution of undefiniteness problem with respect to force distribution. For the first time, a system of active spatial six-degree-of-freedom mechanisms elastically interconnected with the object (dynamic environment) is modeled. The reason for the emergence of the undefiniteness problem with respect to force is explained and the procedure for solving this problem given. Unlike the approaches given in the available literature, the undefiniteness problem with respect to force is solved in accordance with physical phenomena. The modeling procedure is illustrated by a simplified example.


1974 ◽  
Vol 16 (5) ◽  
pp. 322-330
Author(s):  
P. F. Thomason

The transient thermal stresses in an insulated quarter-plane, subject to an instantaneous heat source on a segment of the surface, are determined with the aid of the Green's function for a two-dimensional infinite space. Numerical results for the transient thermal stresses at the surfaces of the quarter-plane are superimposed on previous isothermal results for cutting-load stresses in a π/2 wedge, to provide a model for a metal-cutting tool in the transient stages of a cutting process. The results are related to the problem of the thermal-cracking of cutting tools, and mechanisms of crack nucleation and propagation are proposed for both ceramic and cemented-carbide tools.


2014 ◽  
Vol 682 ◽  
pp. 491-494 ◽  
Author(s):  
Vladislav Bibik ◽  
Elena Petrova

The author considers methods of forecasting metal-cutting tool life based on characteristics of cutting tool material. These characteristics depend on differences in numerical values of physical and chemical properties of tool material due to changes in its composition, structure, and production process variables. The described methods allow obtaining the information necessary for forecasting the tool life beyond the process of cutting, for example at the stage of cutting tool manufacturing. The author suggests using the method of registration of thermo-physical properties of the tool material as a promising forecasting technique.


Author(s):  
Salman Pervaiz ◽  
Sathish Kannan ◽  
Wael Abdel Samad

In machining operation, cutting tool performs a central role towards the overall machining performance. A user from metal cutting community always look for better cutting tools that can enhance productivity by reducing tool wear and cost. Modification in the micro-geometry of cutting edge is termed as edge preparation, and it is performed to improve the machining performance by strengthening the cutting edge, reducing internal stresses of coating and lowering the edge chipping etc. Edge preparation has a controlling influence on the formation of deformation zones, cutting temperature, cutting forces and stresses at the cutting interface. Vibration assisted machining (VAM) concept is gaining fame in the metal cutting sector community for machining difficult-to-machine materials. In VAM, cutting tool moves with a small amplitude vibration instead of moving with a constant cutting velocity. This small amplitude vibrational movement provides better machining performance for difficult-to-cut brittle materials. The current numerical study utilized different edge prepared micro-geometries such as sharp edge, round edge and chamfer edge etc. cutting tools, and then these cutting tools were used in the numerical simulations of VAM. The study shows higher magnitude of cutting forces under VAM with tools with modified geometry. The study is beneficial for the metal cutting community and opens new areas of industrial applications.


2017 ◽  
Vol 260 ◽  
pp. 219-226 ◽  
Author(s):  
Viktors Gutakovskis ◽  
Eriks Gerins ◽  
Janis Rudzitis ◽  
Artis Kromanis

From the invention of turning machine or lathe, some engineers are trying to increase the turning productivity. The increase of productivity is following after the breakout in instrumental area, such as the hard alloy instrument and resistance to wear cutting surfaces. The potential of cutting speed has a certain limit. New steel marks and cutting surfaces types allow significantly increase cutting and turning speeds. For the most operation types the productivity increase begins from the feeding increase. But the increase of feeding goes together with machined surface result decreasement. Metal cutting with high feeding is one of the most actual problems in the increasing of manufacturing volume but there are some problems one of them is the cutting forces increasement and larger metal removal rate, which decrease the cutting tool life significantly. Increasing of manufacturing volume, going together with the cutting instrument technology and material evolution, such as the invention of the carbide cutting materials and wear resistant coatings such as TiC and Ti(C,N). Each of these coating have its own properties and functions in the metal cutting process. Together with this evolution the cutting tool geometry and machining parameters dependencies are researched. Traditionally for the decreasing the machining time of one part, the cutting parameters were increased, decreasing by this way the machining operation quantity. In our days the wear resistance of the cutting tools increasing and it is mostly used one or two machining operations (medium and fine finishing). The purpose of the topic is to represent the experimental results of the stainless steel turning process, using increased cutting speeds and feeding values, to develop advanced processing technology, using new modern coated cutting tools by CVD and PVD methods. After investigation of the machined surface roughness results, develop the mathematical model of the cutting process using higher values of the cutting parameters.


2013 ◽  
Vol 589-590 ◽  
pp. 38-44
Author(s):  
Gang Liu ◽  
Ming Chen ◽  
Peng Nan Li ◽  
Qing Zhen Bi ◽  
Bao Cai Guo

The concept of multi-constrained analysis of the cutting process is presented for the first time in the paper. The paper adopts a method to solve an important problem which is how to judge the influence of constrains during the cutting process. The research results are applied for HSS drills for cutting stainless steel. On the basis of the multi-constrained analysis combined with methods of simulations and standard experiments, the optimum methods are provided for structure, coating and cutting parameters of cutting tools. For geometric structure of tools, optimization is to increase thickness of cutting and rake angle. Coating optimization strategy is choosing high temperature hardness and low thermal conductivity coating. Optimization of cutting parameter is to adjust feed fate, then select proper cutting speed. The conclusion of paper is helpful for the cutting optimization.


Author(s):  
S-L Chang ◽  
H-C Tseng

Owing to the complex geometry of helical cutting tools, several manufacturing processes are required to produce the profile of the cutter and the cutting angles. If the traditional method of manufacture were used, the cost would be frustratingly expensive. In this paper, a novel straight-sided hob cutter design consisting of two curved cutting edges and three straight cutting edges with different pressure angles is proposed. By applying designed rake profile equations of a hob cutter, the principle of coordinate transformation, the theory of differential geometry, and the theory of gearing, a mathematical model of the helical cutting tool is derived. In addition, the cutting angles, the condition of full undercutting, and the width of the top land of the cutter are also studied. The novelty of the design is such that the multiangles of the helical cutting tool can be manufactured in one hobbing process, thereby simplifying the manufacturing process. The results and concepts proposed in the paper will be beneficial as design guidance for tool designers, will enhance the manufacturing processes of helical cutting tools, and will assist tool-related industries in upgrading their technology and competitiveness.


SINERGI ◽  
2020 ◽  
Vol 24 (3) ◽  
pp. 171
Author(s):  
Sobron Yamin Lubis ◽  
Sofyan Djamil ◽  
Yehezkiel Kurniawan Zebua

In the machining of metal cutting, cutting tools are the main things that must be considered. Using improper cutting parameters can cause damage to the cutting tool. The damage is Built-Up Edge (BUE). The situation is undesirable in the metal cutting process because it can interfere with machining, and the surface roughness value of the workpiece becomes higher. This study aimed to determine the effect of cutting speed on BUE that occurred and the cutting strength caused. Five cutting speed variants are used. Observation of the BUE process is done visually, whereas to determine the size of BUE using a digital microscope. If a cutting tool occurs BUE, then the cutting process is stopped, and measurements are made. This study uses variations in cutting speed consisting of cutting speed 141, 142, 148, 157, 163, and 169 m/min, and depth of cut 0.4 mm. From the results of the study were obtained that the biggest feeding force is at cutting speed 141 m/min at 347 N, and the largest cutting force value is 239 N with the dimension of BUE length: 1.56 mm, width: 1.35 mm, high: 0.56mm.


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