Initial tool surface and projection of the cutting instrumentJournal: Journal of Engineering Sciences (Vol.1, No. 1)
Publication Date: 2014-11-13
Authors : S. V. Shvets;
Page : A12-A19
Keywords : surface; workpiece; formation; motion; tool; contact;
Many authors aspire to generalize process of design of working part of cutting tool. P.R. Rodin uses two elements of the mechanism operating in workpiece machining time (a surface of a workpiece and an initial tool surface). It is considered that the cutting tool is a body restricted to an initial tool surface. It is considered that the cutting tool, is the body restricted by an initial tool surface. It has ability to cut off metal, contacting with it while the machining. And then the sequence of design seems obvious: the initial tool surface is defined and turns to the efficient cutting tool. However, in most cases, the shape of an initial tool surface uniquely is not defined neither by the workpiece shape, nor by available relative movements of the two links mentioned above. Contact be-tween them can be linear (fixed or periodic) or point (also fixed or periodic). Hence, attempts to generalize and formalize technique of design of various aspects and types of tools yet have not given desirable results. The paper purpose: to define real possibilities of the theory which is founded on concept of an initial tool surface, concerning design of the cutting tool. The tool executes two functions: contacts to metal, disjointing it in certain sequence on a shaving (the cutting scheme), and shapes a workpiece surface at linear or point contact (methods of for-motion of shapes). Leaving invariable positions of the theory of formation of shapes concerning interaction of two links of some mechanism, it is necessary to consider as an initial tool surface is the surface which, at corresponding relative movement, shapes a workpiece surface. It can be both real surface which really restricts an tool body, and the surface, organized by movements contacting with workpiece surface and with elements of the body of the tool (a point or a line). Set of initial tool surfaces (both material and created by kinematics) does not allow to offer the formalized technique of design of the tool. a Heuristic method of the morphological analysis is possible to be used. Selection of possible decisions for separate parts of the tool (morphological signs) and their system combination thus is carried out. The possible amount of combinations (tool constructions) depends on limitation of movements, an aspect of contact, an aspect and a combination of movements, the selected shape of an initial tool surface. The algorithm of design of the metal-cutting tool, based on the usage of concept of an initial tool surface and a method of the morphological analysis is created. Definition of an initial tool surface as surface which restricts body of the cutting tool, gives information concerning projecting only separate aspects of cutting tools. If the initial tool surface (even imaginary) is the surface which contacts workpiece surface during shape formation it is possible to create bodies (tools) and movements which are capable to recreate it. At linear contact of workpiece surface and an initial tool surface there is a possibility of definition of an initial tool surface as surface which restricts an tool body. If at least one invariable co-ordinate line is on a workpiece surface there is a possibility of creation of the tool with linear contact to a workpiece surface. At point contact of the tool to a workpiece, the initial tool surface is organized by movements of a point contact therefore it is imaginary and depends on kinematics of the machine tool and design features of the workpiece. The concept of an initial tool surface can be used for the analysis and definition of possible shapes of surfaces, which are capable to contact to a workpiece surface. On the basis of these shapes movements and tool constructions are designed. Heuristic component of process of projecting of the tool is very essential and depends on intuition, experience and an intellectual choice.
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