The physical phenomenon in metallic cutting and basic rule (3)

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2, cutting force reachs his main influencing factor. Cutting force is one of elementary physics phenomena in metallic cutting process, it is the main technique parameter when analysing machine tool of mechanism craft, design, cutting tool, clamping apparatus.   (one) when cutting of metal of   of component of force of the origin of cutting force, cutting, cut and its treatment apparently generation flexibility and plasticity are out of shape; At the same time the opposite movement between workpiece and cutting tool is occurring attrition force. If graph 2-15 place is shown, action has two parts to comprise in the force on cutting tool: 1.

Action is advanced, hind on knife face be out of shape γ of the Fn that fight force and   of   of Fn α ; 2.

Action is advanced, after the γ of attrition force Ff on knife face and Ff α . The join forces F of these force calls cutting resultant force, also call total cutting force. F of total cutting force but edge X, y, z direction is decomposed for Fc of 3 mutual and perpendicular component of force, Fp, Ff, if pursue,2-16 place is shown. Advocate F of force of total cutting of cutting force Fc is in advocate the component of force on athletic way; F of force of total cutting of back force Fp is in perpendicular at assuming the job is planar the component of force on direction; Force of total cutting of feed force Ff moves in feed the component of force on direction. The economic sense of each component of force when turning is as follows: Advocate action of cutting force F C at advocate athletic way, it is computer bed advocate dosage of cutting of intensity of athletic orgnaization intensity and arbor, razor blade and clamping apparatus of design machine tool, choice main basis, also be to consume the cutting power with maximum power. When the circle outside vertical car of back force F P, back force F P does not consume power, but its action is on the way with machining complex the wrongest tigidity, make workpiece is out of shape inside horizontal easily, affect workpiece precision, cause vibration easily. F P is the necessary basis of stiffness of desired result machine tool. Action of feed force F F is on the feed orgnaization of the machine tool, it is the main basis of intensity of orgnaization of desired result feed. (2) the method that   of formula of experience of cutting force calculative passes a test, measure the cutting force data when giving all sorts of influencing factor to change, try to handle the gotten expression that reflects each element and cutting power concern, call formula of experience of cutting force calculative. In actual in the experience formula of use cutting force has two kinds: It is exponential formula, 2 it is unit cutting force. 1. Exponential formula   advocate cutting force (back force of 2-4)   (force of feed of 2-5)   (the Fc in type of 2-6)   -- -- advocate cutting force (N) ; Fp -- -- back force (N) ; Ff -- -- feed force (N) ; Cfc, Cfp, Cff -- -- coefficient, can check watch 2-1; Xfc, Yfc, Nfc, Xfp, Yfp, Nfp, Xff, Yff, Nff------Index, can check watch 2-1. KFc, KFp, KFf----Correction coefficient, can check watch 2-5, express 2-6. 2. Force of cutting of unit of   of unit cutting force is point to unit cutting area to go up advocate cutting force, express with Kc, see watch 2-2. The AD in type of   of H D) (2-7) of · of F)=F C/(b D of · of Kc=Fc/A D=Fc/(a P-------Cutting area (Mm 2) ; Ap-------Back penetration of a cutting tool is measured (Mm) ; F --------Feed (Mm/r) ; Hd--------Cutting ply (Mm) ; Bd--------Cutting width (Mm) . Kc of force of foregone unit cutting, beg advocate the K C in 2-8 of type of   of Bd (2-8) of · of Hd of · of F=kc of · of Ap of · of Fc=kc of   of   of cutting force Fc is to point to F = 0.

The unit cutting force when 3mm/r, be more than when actual feed F or be less than 0.

When 3mm /r, need to multiply in order to amend coefficient Kfkc, see watch 2-3. Express 2-3 feed? To the correction coefficient Kfkc of unit cutting force or unit cutting power, kfpsf /(mm/r)0.










6Kfkc, kfps1.









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