Graphical method of cutting force analysis in orthogonal cutting of metal cutting proposed by scientists ernst and merchant. A merchant circle diagram is a graphical representation of number of forces acting on a workpiece during metal cutting operation. Merchant circle diagram is used to analyze the forces acting in metal cutting. Manufacturing engineering and technology, 3rd edition, by s. Kalpakjian, addison wesley publishing company, 1993. This will first be explained with vector diagrams, these in turn will be followed by a few formulas. Shear surface is a plane extending upwards from the cutting edge. Metal cutting theory and practice, third edition shapes the future of material removal in new and lasting ways. For metal cutting problems, an incremental analysis must be carried to the limit load condition so that the workpiece begins to flow steadily under a constant loading condition. Oblique cutting the cutting edge is inclined at an angle i known as inclination angle with the normal to the direction of tool travel. Metal cutting or machining is the process of by removing unwanted material from a block of metal in the form of chips. Shear plane is locatedwhere least energy is required for shear.
Manufacturing technology ii theory of metal cutting k. Me 3217 metal cutting principles credits and contact hours. Merchant circle, can be constructed if the followings are known. Cutting processes i cutting processes process planning, cost, quality, rate and flexibility. Ernst and merchant do this scientific analysis for the first time in 1941 and gives the following relation in 1944 it is convenient to determine various force and angles. Two 50 minute lectures and one 2 hour lab per week. The merchants model, as the most famous approach of orthogonal cutting, is widely used in introductive courses on machining. Theory of lee and shaffer, stress distribution on rake face. Rounding out the treatment, an entire chapter is devoted to machining economics and optimization. Cutting temperature 2 introduction everyday experience. An orthogonal cutting of steel is done with 10 rake tool, with a depth of cut 2mm and feed rate of 0. A comparative study was done with 1006 steel, 6al4v. In a cutting process, the workpiece moves at a constant speed.
Cutting force is the main factor for the study of cutting process. Endowing you with practical knowledge and a fundamental understanding of underlying physical concepts, metal cutting theory and practice, second edition is a necessity for designing, evaluating, purchasing, and using machine tools. Merchants second solution modified merchants theory. Discuss the ernstmerchant theory and lee and shaffer. By manish jindal, iitian gate academy, chandigarh, pt, metal cutting, merchant circle, part 1, for gate mechanical, ies, psu and govt jobs. Force modeling in metal cutting is important for tool life estimation, chatter prediction, and tool condition monitoring purposes. The term machining is used to describe various processes which involve removal of material from the workpiece definition of machining or metal cutting machining is an essential process of. Application of merchant theory in machining particulate. In machining ductile metals like steels with long chiptool contact length, lot of stress. Theory of metal cuttingmechanics of metal cutting force heat. Orthogonal cutting uses a wedgeshaped tool in which the cutting edge is perpendicular to the direction of cutting speed. The analysis of three forces system, which balance each other for cutting to occur. Scribd is the worlds largest social reading and publishing site.
Yang department of mechanical engineering and applied mechanics, the university of michigan, ann arbor, michigan 48109, u. There are 3 triangle of forces acting during metal cutting operation. Pt, metal cutting, merchant circle, part 1 youtube. Concept of rake and clearance angles of cutting tools. Explain the metal cutting theories in detail and explain any one of them. Ernst and merchant developed the first reasonable theory in metal cutting. However, despite all the effort that has been expended, it is still not possible to predict the performance of a cutting tool based on the geometry and kinematics of the system and basic material properties. Theory of metal machining overview of machining technology theory of chip formation in metal machining force relationships and the merchant equation power and energy relationships in machining cutting temperature. Generalization of the leeshaffer solution in the theory. Because no further development is indicated in the book, one may get the impression that the end of the metal cutting history is reached at this point. However, the shear angle predicted by the merchants model from the criterion of minimization of the cutting energy, does not generally agree with experimental data and numerical simulations.
Theory of metal cutting 2 authorstream presentation. The merchants model of orthogonal cutting revisited. For given cutting conditions, the work done is proportional to fc an expression has been developed for fc in terms of the shear angle. As the tool is forced into the material, the chip is formed by shear deformation along a plane called the shear plane, which is oriented at an angle f with the surface of the work. Earnstmerchantminimum energy criterion shear plane is located where least energy is required for shear. Material removal is essentially done on machine tools, which may be lathe, milling, drilling, shaping, planing, broaching and grinding machines. Theory of metal cuttingmechanics of metal cutting free download as powerpoint presentation. Downloadtheory of metal cutting by bhattacharya pdf. Elementary treatement of metal cutting theory element of cutting process geometry of single point tool and angles chip formation and types of chips built up edge and its effects chip breakers. The cutting forces generated in metal cutting have a.
Metal cutting is the process of removing unwanted material in the form of chips, from a block of metal. Machine tools are kind of machines on which metal cutting or. Two types describing the nature of the deformation zone in metal cutting. Many components produced by primary manufacturing processes need machining to get their final shape, accurate size and good surface finish. Merchant s circle diagram is constructed to ease the analysis of cutting forces acting during orthogonal two dimensional cutting of work piece. Then, according to boothroyd, metal cutting history had stalled until 1941 when ernst and merchant published their fundamental work. Metal cutting is a process that has been extensively studied for the past half century. Rake angle and clearance angle are the most significant for all the cutting tools. Shear strength of metal along shear plane is not affected by normal stress. The shearing strain undergone by the metal during chip formation, and the.
Kim 2 cutting processes objectives product quality. Centered on metallic work materials and traditional chipforming cutting methods, the book provides a physical understanding of. Theory of metal cuttingmechanics of metal cutting force. An analysis of the chip geometry and the force system found in the case of orthogonal cutting accompanied by a type 2 chip has yielded a collection of useful equations which make possible the study of actual machining operations in terms of basic mechanical quantities. Theory of metal cutting 1 define the following tool angles in asa system of tool signature and show them by drawing a neat sketch of single point cutting tool. Explain the various forces acting in orthogonal cutting. Metal cutting is the predominate use for highpower carbondioxide lasers, although welding accounts for 20% of the carbondioxide lasers installed in the. No cutting tool is perfectly sharp, and in the idealized picture as shown in figure 2 the cutting edge is represented by a cylindrical surface joining. Mrr, tool wear physics of cutting mechanics force, power tool materials design for manufacturing 2. Thus the metal gets compressed very severely, causing shear stress.
The surfaces of tools used in metal cutting and chipless forming can be locally hardened by spark erosion coating with cemented carbide. Scraping the ice from your windshield edge angle of the ice scraper force required depending on the characteristics of ice incentives. Summary the orthogonal metal cutting process for a controlled contact tool is simulated using a limit analysis theorem. Kim 3 orthogonal cutting in a lathe rake angle shear angle t o. List out the assumptions made in merchant thing shear plane model. Kovrizhnykh 1 doklady physics volume 53, pages 11 14 2008 cite this article. The objective of this preliminary experimental work is to application the merchant theory in machining particulate metal matrix composites during the short tests in radial turning of special workpieces in pmmcs with k20 cutting tools. Theory of metal cutting free download as powerpoint presentation. Machine toolsmachine tools are kind of machines on which metal cutting ormetal forming processes are carried out.
Merchants theory free download as powerpoint presentation. A complete reference covering the latest technology in metal cutting tools, processes, and equipment. Buy metal cutting theory and practice manufacturing engineering and materials processing 2 by stephenson, david a. Generalization of the leeshaffer solution in the theory of metal cutting a.
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