RU2191677C1 - Grinding wheel forming method - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: method can be applied at relative radial and longitudinal feeds of rotating grinding wheel and dresser. Cutting wheel or set of cutting wheels is used as dresser which is installed under crossing angle (-α) relative to axis of grinding wheel. Longitudinal feed is imparted to grinding wheel to form inclined ring groove on its surface. Fed at one full turn of wheel and angle α of groove tilting. Radial feed is imparted to cutting wheel after each full revolution of grinding wheel. Direction longitudinal feed of grinding wheel to opposite and angle of crossing of axes from (-α) to (+α) are changed after each turning of wheel through 180^°. Such operations make it possible to form longitudinal interrupted grinding wheel combining advantages of interrupted grinding with conventional grinding by solid wheels and decreasing degree of roughness owing to oscillation of cutting working surface of wheel interrupted in longitudinal direction. EFFECT: improved conditions of cutting, self-dressing and delivering of lubricating and cooling liquid with resulting increased capacity of machining and improved quality. 3 cl, 1 ex, 6 dwg

Description

 The invention relates to mechanical engineering, in particular to methods for forming grinding wheels.

 A known method of dressing the grinding wheel with the formation of the cutting surface with depressions along the Archimedean spiral, where the radial feed is carried out simultaneously with the reciprocating movements of the ruling tool [1].

 The disadvantage of this method is the low resistance of the ruling tool due to the large values of the longitudinal feed when dressing according to the turning method, the value of which is greater than the speed of rotation of the grinding wheel, while the method does not allow the formation of axially offset grooves on the periphery of the wheel, which can significantly reduce the grinding temperature, thanks to the running contact method.

As a prototype, the method of forming a grinding wheel, which is carried out under conditions of relative radial and longitudinal feeds of a rotating grinding wheel and a rotating disk ruling tool [2], was selected. The longitudinal feed is reported to the grinding wheel from the condition of the formation of an inclined axially-shifted cutting layer on it and its value is determined for the full revolution of the wheel according to the above formula. Radial feed inform the power tool after each full turn of the grinding wheel. The direction of the longitudinal feed of the grinding wheel is reversed after each rotation of 90 ^o . After the formation of the axially offset cutting layer from one end of the circle, the latter is rotated 180 ^o relative to its axis of symmetry and 180 ^o relative to its axis of rotation to form a layer from the other end.

 The disadvantage of this method is that it does not make it possible to form axially displaced grooves on the periphery of the circle, which can significantly reduce the grinding temperature, due to the use of the traveling contact method.

 The objective of the invention is the combination of the dressing process with the formation of axially offset grooves on the periphery of the circle, which can significantly reduce the grinding temperature, due to the use of the running contact method.

This is achieved by the proposed method of forming a grinding wheel in conditions of relative radial and longitudinal feeds of a rotating grinding wheel and a cutting tool, while a rotating cutting wheel or a set of cutting wheels is taken as the cutting tool and set longitudinally at a crossing angle (-α) to the grinding wheel axis the feed is reported to the grinding wheel from the condition of the formation on its periphery of the inclined annular grooves and determine the feed rate for the full revolution of the wheel by the formula
S $\genfrac{}{}{0ex}{}{\text{o}}{\text{etc}}$ = Dtgα,
where D is the outer diameter of the grinding wheel, m;
α is the acute angle of inclination of the grooves to a plane perpendicular to the axis of rotation, deg.,
and the radial feed is reported to the cutting wheel after each full revolution of the grinding wheel, while changing the direction of the longitudinal feed of the grinding wheel to the opposite and the angle of intersection of the axes from (-α) to (+ α) after each rotation of 180 ^° .

Moreover, the width of the annular groove for single-ring small height grinding wheels is chosen from the condition
B _to ≅ 0.25 B _w ,
where _W - the height of the grinding wheel, m;
the angle α of the inclination of the groove to the plane perpendicular to the axis of rotation is determined by the formula
α≥arctg (B _to / D).
In addition, for the formation of two or more grooves on multi-groove grinding wheels with a high height, an assembly tool of two or more cutting wheels with an axial distance between the cutting wheels equal to the axial distance between the grooves of the grinding wheel is taken as the ruling tool.

 In FIG. 1 shows the relative position of the grinding wheel and the cutting tool after the formation of the groove; in FIG. 2 - position of the governing instrument at an angle (-α), view along A in FIG. 1; figure 3 - position of the ruling tool at an angle (+ α), view along B in figure 1; figure 4 - the formation of two grooves with a combined ruling tool; figure 5 and 6 - scan trace of a two- and single-groove grinding wheel on the work surface.

The method of forming the grinding wheel is carried out under conditions of relative longitudinal feed S _p of the grinding wheel 2 rotating relative to axis 1 and radial S _{rad of the} feed of the ruling tool 4 rotating relative to axis 3.

As the ruling tool 4 take a rotating cutting wheel or a set of cutting wheels and set its axis 3 at a crossing angle (-α) to the axis 1 of the grinding wheel 2 ( _figure 2), while the longitudinal feed S _p inform the grinding wheel 2 from the conditions of formation on its periphery of the inclined annular groove and determine its value for a full revolution of the circle according to the formula
S $\genfrac{}{}{0ex}{}{\text{o}}{\text{etc}}$ = Dtgα,
where D is the outer diameter of the grinding wheel, m;
α is the acute angle of inclination of the groove to the plane perpendicular to the axis of rotation, deg.

The radial feed _{Srad is} reported to the cutting _wheel 4 after each complete revolution of the grinding wheel 2, while the direction of the longitudinal feed _{Sp of the} grinding wheel 2 is reversed and the axis crossing angle is changed from (-α) to (+ α) after each rotation by 180 ^o (figure 3).

The width of the annular grooves for single-ring small height grinding wheels 2 (Fig.1-3, 6) is selected from the condition
B _to ≅ 0.25 B _w ,
where _W - the height of the grinding wheel, m

The angle of inclination of the grooves to the plane perpendicular to the axis of rotation 1, is determined by the formula
α≥arctg (B _to / D).
To form two or more grooves on multi-groove grinding wheels 2 (Fig. 4) with a high height, a tool made of two or more cutting wheels 4 with an axial distance between the cutting wheels equal to the axial distance B _about between the grooves of the grinding wheel 4 is taken as the ruling tool .

применяемый для обработки поверхности плоских образцов из стали ШХ15 HRC 59... 62 при V_кp= 35 м/с; V_д=0,2 м/с; t=5•10^-5 м. Охлаждение - 3,5%-ный раствор НГЛ-205 в воде. В качестве правящего инструмента принимали отрезной круг 150•4•32 14А40Н СТ341 БУ 80 м/с 2 кл. по ГОСТ 21963-82. Формирование производили на круглошлифовальном станке мод. ЗБ151. Режимы формирования: 1) скорость вращения шлифовального круга V_шк=0,66 м/с; частота вращения шлифовального круга N_шк= 63 об/мин; 2) скорость вращения правящего инструмента V_пи= 25,45 м/с; частота вращения правящего инструмента N_пи=3240 об/мин; 3) припуск на формирование (глубина канавки) 5 мм; 4) радиальная подача правящего инструмента S_рад=0,1 мм/дв.ход; 5) продольная подача шлифовального круга: определяем по формулам S $\genfrac{}{}{0ex}{}{\text{o}}{\text{пр}}$ = D•tgγ - подача за 1 оборот шлифовального круга (мм/мин); S $\genfrac{}{}{0ex}{}{\text{м}}{\text{пр}}$ = D•tgγ•N_шк - минутная подача шлифовального круга (мм/мин)
S_пр ^м=200•tg1^o30'•63=252 (мм/мин).Example. A 23A25CM1K6 grinding wheel was formed (D = 200 mm, B = 16 mm) to obtain an axially offset cutting layer with an inclination angle

used for surface treatment of flat samples of steel ШХ15 HRC 59 ... 62 at V _кp = 35 m / s; V _d = 0.2 m / s; t = 5 • 10 ^-5 m. Cooling - a 3.5% solution of NGL-205 in water. The cutting wheel 150 • 4 • 32 14А40Н СТ341 БУ 80 m / s 2 cells was used as the ruling tool. according to GOST 21963-82. The formation was carried out on a mod grinding machine. ZB151. Formation modes: 1) grinding wheel rotation speed V _шк = 0.66 m / s; grinding wheel rotation frequency N _шк = 63 rpm; 2) the rotation speed of the ruling tool V _pi = 25.45 m / s; the speed of the ruling tool N _pi = 3240 rpm; 3) formation allowance (groove depth) 5 mm; 4) the radial feed of the ruling tool S _rad = 0.1 mm / dv.hod; 5) the longitudinal feed of the grinding wheel: determined by the formulas S $\genfrac{}{}{0ex}{}{\text{o}}{\text{etc}}$ = D • tgγ - feed per 1 revolution of the grinding wheel (mm / min); S $\genfrac{}{}{0ex}{}{\text{m}}{\text{etc}}$ = D • tgγ • N _shk - minute feed of the grinding wheel (mm / min)
S _pr ^m = 200 • tg1 ^o 30 '• 63 = 252 (mm / min).

Circular grinding machine mod. ZB151 allows you to adjust the speed of the longitudinal feed S _PR ^m steplessly in the range from 100 to 6000 mm / min.

 The roughness of the surface treated with a grinding wheel formed in accordance with the proposed method is Ra = 1.25 μm.

Invention allows
combine the editing process with the formation of the cutting surface of the circle with an axially-shifted layer at the inner ends;
to obtain an abrasive wheel that works according to the running contact method by forming an axially displaced cutting layer on its working surface due to the inclined annular groove, thereby significantly reducing the grinding temperature.

 Due to the running contact obtained due to the inclination of the inner ends and the axial clearance interrupting the contact of the wheel with the workpiece in the axial direction, it is possible to significantly reduce the temperature in the cutting zone and to avoid the occurrence of grinding defects.

 Therefore, the longitudinally discontinuous grinding wheel obtained as a result of the formation makes it possible to toughen cutting conditions with a guarantee of free processing, improve quality and increase productivity. The design of the formed grinding wheel provides for the processing of the overlapping of the cutting zones of the abrasive left and right parts to each other (Fig.5-6).

 Formed longitudinally discontinuous grinding wheel, having an annular inclined groove and bevelled at an angle α to a plane perpendicular to the axis of rotation, the internal ends, allows you to combine the advantages of intermittent grinding with the usual traditional - solid circles.

 This increases the strength of the tool, since the outer ends of the circle are perpendicular to the axis of rotation, the vibration resistance of the process, quality and productivity due to the oscillation of the middle part of the circle with the inner ends.

 In addition, the consumption of abrasive per unit of metal removal is reduced.

 Formed by the proposed method, the circle reduces the roughness of the treated surface by 1-2 classes and the expansion of technological capabilities due to oscillations and discontinuous in the longitudinal direction of the cutting working surface of the circle. This improves the conditions of cutting, self-sharpening and coolant supply, which allows to increase the quality and productivity of processing.

 The proposed method for the formation of longitudinally discontinuous grinding wheels can be used in any metalworking enterprises engaged in grinding hard-to-handle materials and, as a result of changing the axial clearance and the angle of inclination of the inner ends of the wheel, can increase the processing productivity by optimizing the heat stress of the process when processing various materials and the quality of the process the oscillation of the middle part of the cutting zone.

Sources of information
1. Copyright certificate SU 1266716, cl. B 24 B 53/00, 1986.

 2. Patent SU 2100180, cl. B 24 B 53/04. A method of forming a grinding wheel. Stepanov Yu.S., Afonasyev B.I., Burnashov M.A. - prototype.

Claims (2)

1. The method of forming the grinding wheel in terms of relative radial and longitudinal feeds of the rotating grinding wheel and the ruling tool, characterized in that as the ruling tool using a cutting wheel or a set of cutting wheels and set it at a crossing angle (-α) to the axis of the grinding wheel, the longitudinal feed is reported to the grinding wheel from the condition of the formation of an inclined annular groove on its periphery and the feed rate for the full circle revolution is determined by the formula
S $\genfrac{}{}{0ex}{}{\text{o}}{\text{etc}}$ = Dtgα,
where D is the outer diameter of the grinding wheel, m;
α is the acute angle of inclination of the grooves to a plane perpendicular to the axis of rotation, deg.,
and the radial feed is reported to the cutting wheel after each full revolution of the grinding wheel, while changing the direction of the longitudinal feed of the grinding wheel to the opposite and the angle of intersection of the axes from (-α) to (+ α) after each rotation of 180 ^° . 2. The method according to p. 1, characterized in that the width of the annular groove for single-ring small height grinding wheels is chosen from the condition
B _to ≅ 0.25 B _w ,
where _W - the height of the grinding wheel, m;
the angle α of the inclination of the groove to the plane perpendicular to the axis of rotation is determined by the formula
α≥arctg (B _to / D).
3. The method according to claim 1, characterized in that for the formation of two or more grooves on multi-groove grinding wheels with high height using a set of two or more cutting wheels with an axial distance between them equal to the distance between the grooves of the grinding wheel.

Images