SU764942A1 - Method of working by abrasion - Google Patents

Description

one

The invention relates to abrasive machining of parts in the metalworking industry.

There is a method of abrasive machining, in which the parts report a gradual movement relative to the grinding wheel, and a rotating one. grinding disc grinding - radial feed. The method is characterized by repeatedly (100 or more times) exceeding the speed of rotation of the grinding wheel, which determines the cutting speed, over the speed of the hypothetical displacement G11.

Such a ratio of speeds, especially when flat grinding worsens the removal of chips from the cutting grains of the grinding wheel, accelerates its salinification. Especially dangerous is 20 this phenomenon when processing viscous and colored materials. As a result, the number of edits increases dramatically and the removal of metal per unit of time is reduced.

The purpose of the invention is to improve the removal efficiency of the material with increasing durability of the grinding wheel. . This is comprehended by the fact that the speed of the translational movement of the part is chosen to be comparable or equal to

rotation speed of the grinding wheel with their opposite direction.

FIG. 1 is a diagram of a method for moving a flat, part along a circular path; in fig. 2 - the trajectory of movement of abrasive grains during flat grinding.

Details 1 in the form of a flat ring impart angular velocity and g along a circular path, which corresponds to the average speed at an average radius g of a ring of width B. The grinding wheel 2 is set by the periphery parallel to the end surface of the part 1 and rotates at a frequency of EoT providing the velocity Vj in the area of contact with the part opposite to the speed of the part Vg. The speed of rotation of the circle V is comparable to or equal to the speed of the translational movement of the part ML. Absolute equality cannot be due to practical grinding conditions: the speed varies across the width of the part due to the variable radius, oscillation, rotational frequencies of the part L7c and KpyraiO, caused by kinematic errors and force loading of the drives. To remove the allowance along the depth of the part, the grinding wheel 2 reports the radial flow S per part, the equation of the trajectory of grain movement 3 is the trachoid Z R.sincf + R (f: / KY R.cos cp + R / K (1) where. (F - the current angle of rotation of the grain R is the radius of the location of the grain Vg, the ratio of the speeds. At a known step P between the grains, the number of grains on the periphery of the circle is r -. Then the shift of the trajectories of the grains relative to each other is uZ g + - Z, - - (2) the grain is determined in the section normal to the trajectory of relative motion — the trachoid; from a curvilinear three an angle with a right angle at point A (see FIG. c, z AZ S In ((p - ./k)) (3) where / U is the angle of elevation of the trachoid relative to a circle of radius R. From the velocity plan at point A according to the sine theorem is defined. -sjn {f. where V is the resultant speed at point A according to the cosine theorem v4v | + t2V -V.co5 (f. For small depths of cut corresponding to the radial feed of a circle of order S 0.01-0.05 mm on the part stroke with sufficient accuracy, V Vg + VK By substituting this value of the resulting speed into formula (4), expressing the ratio of the speeds in terms of the coefficient K, after conversion determines with ju hrp} Substituting in formula (3) the value of ju, and also the parameter (2), after transformations, with sufficient accuracy is obtained P- (f 2ftR (p (5) m {K + r) The maximum thickness of the slice is removed when the grain leaves the contact with detail on the angle fd, b1c corresponding to the allowance t - S fat t l I 2 b and e pchmo.) / (f.c. Abrasive processing mode is characterized by the volume of the material to be squeezed per unit of time. In order to determine it, in addition to the thickness of the medium, it is necessary to know the length of the contact of the abrasive grain with the part. Contact length ((Composed of the arc of rotation of the abrasive grain at the incision angle tjf and the angle of emergence of the poppy from the part and the relative translational movement of the contact angle "VwHtc -I: e .-" W, ".. f..VT, The incision angle corresponds to stating the circle relative to the part „ft R Substituting this value Z into equation (1), we get after transformation - {5. ,,. The solution of this transcendental equation: n The error does not exceed 3% with the value (f up to 30 °, which is quite consistent There is an abrasive machining allowance. Substituted values of q), and am in f formulas (6) and (7) determine the length of the contact of the abrasive grain. The volume of the metal being cut by the abrasive grain (nominee V o asr-L-E. The average thickness of the cut is half the maximum. According to the formula (5): OMaiiC itR4Mat: c ii / T / 2Rt 2 m (.k4-0 m {k4,) Substituting the values (8) and (9) into the volume formula, we obtain: r bfiJgRt: I, ..R y -. +,: Mk k. Dependency analysis (10 ), (9) and (8) shows that with an increase in the ratio of the speed of the tool to the speed of translational movement (k), the volume of the material being cut, the thickness of the cut and the contact length of the abrasive grain do not decrease to the same extent. Thus, when the volume of the metal being cut decreases almost directly proportionally with increasing K, the thickness of the cut also changes in the same way as. But when the slice thickness decreases by 5-8 times less than the volume of metal being cut A, the contact length c decreases slightly with increasing and the smaller, the larger K. With an increase of 100 times the ratio of the speed of the grinding wheel, to the speed of translational movement of S 2, 5 times in the future almost does not decrease, rushing to its limit. . -STC. Therefore, a decrease in the volume of the metal being cut with an increase in the SNW occurs due to a decrease in the thickness of the cut, which in its limit tends to zero. On this basis, the speed of the translational movement of the part according to the proposed method is selected, .. so-. measurable or equal to the rotation speed of the grinding wheel, i.e. .

Claims (1)

Claim The method of abrasive machining, in which the parts communicate progressive movement relative to the grinding wheel, and to the rotating spy ^! the radial feed is informed to the bevel wheel, characterized in that, in order to increase the material removal efficiency while increasing the resistance of the grinding wheel, the translational speed of the part is chosen commensurate with or equal to the rotation speed ^{3 of the} grinding wheel in the opposite direction.