UA141255U - METHOD OF DEEP GRINDING OF CYLINDRICAL PARTS - Google Patents

Abstract

A method of grinding a cylindrical part by the periphery of a grinding wheel made of synthetic superhard material, in which the grinding wheel is rotated and the part is rotated and reciprocating, while the grinding wheel is controlled by mechanical action on its diamond-containing layer. In this case, pre-grinding of the grinding wheel is carried out by grinding the part selected from the batch of workpieces, measuring the power consumed during grinding and idling of the machine table, set the energy consumption of processing, and then grind the batch of parts.

Description

A useful model belongs to the field of mechanical engineering, namely metalworking, and can be used in the grinding of cylindrical parts made of tooling and structural materials with a wheel made of synthetic superhard material.

There is a known method of deep grinding of a cylindrical part by the periphery of a grinding wheel made of a synthetic superhard material, by which the grinding wheel is brought into a rotational movement, and the part - into a rotational and reciprocating movement (11.

The disadvantage of the known method of deep grinding of a cylindrical part with the periphery of a grinding wheel made of synthetic superhard material is the occurrence of a significant cutting temperature, which leads to the formation of burns and other temperature defects on the processed surface of the part, which reduces its quality and operational properties.

There is also a known method of grinding a grinding wheel made of synthetic superhard material by the method of mechanical action on its diamond-containing layer (by grinding with an abrasive bar), which ensures its high cutting ability and, accordingly, a reduction in the cutting temperature and an increase in the quality of the processed part and its operational properties |21. This method was chosen as the closest analogue.

However, this method does not provide the maximum possible processing performance for a given cutting temperature.

The useful model is based on the task of improving the method of deep grinding of a cylindrical part by means of the fact that, after grinding the grinding wheel, the part selected from the batch of processed parts is first polished, the power consumed during grinding and idling of the machine table is measured, and the energy intensity of the processing is determined according to a certain dependence, after which the grinding of a batch of parts is carried out at the speed of rotation of the part, which is set according to a certain dependence, which ensures an increase in processing productivity for a given cutting temperature and, accordingly, an increase in the quality of the processed surface.

The problem is solved by the fact that in the method of deep grinding of a cylindrical part by the periphery of a grinding wheel made of a synthetic superhard material, in which the grinding wheel is driven into a rotational movement, and the part - into a rotational and reciprocating movement, while the grinding wheel is controlled by the method of mechanical action on its diamond-containing layer, according to a useful model, before and after the grinding wheel, the part selected from the batch of processed parts is polished, the power consumed during grinding and idling of the machine table is measured, and the energy consumption of the processing is determined according to the dependence:

In: Mdetisi, after which the grinding of the batch of parts is carried out at the speed of rotation of the part, which is set according to the schedule and 1 - 8. e Utah -e a gne

From tach to M, processing energy, N/m; 70717772 - effective grinding power, W;

M.; Magician. power consumed during grinding and idling of the machine table, W; y - longitudinal feed for one revolution of the part, m; det! - speed of rotation of the part selected from the batch of processed parts, m/s; in grinding depth, m; det - speed of rotation of the part, m/s; emz2.72; 5 - cutting temperature, degrees; tak Der). maximum cutting temperature, degrees;

C - specific heat capacity of the processed material, J/(kg" degrees);

R. density of processed material, kg/m3; a-ADegr). coefficient of thermal conductivity of the processed material, m/s; and - thermal conductivity coefficient of the processed material, W/m'grad.); t - radius of the grinding wheel, m.

To implement the proposed method, first measure the power consumed during grinding - 1 and idling of the machine table - 2, determine the effective grinding power М ММ and set the processing energy З according to the expression: сойКЗБВВВЗЗ- ШЗ Я :2 --

Vittdeti(), which allows to significantly increase the productivity and quality of processing of a given cutting temperature 9 due to a significant increase in the speed of rotation of part 4297 in the conditions of deep grinding according to the dependence; | and 1- (t) o e Utakh -e a 2 8 tah ; (2)

In dependence (1), the Vi parameter should be taken as equal to or greater than half of the grinding wheel diameter; speed of rotation of the part selected from the batch of processed parts, det! should be set within 0.5...5 m/s, and the grinding depth should be set within 0.1...1 mm.

The important conclusion follows from dependence (2) that with an increase in the speed of rotation of the part "det, the cutting temperature 9 continuously increases, asymptotically approaching a constant (maximum) value equal to , close to the maximum cutting temperature o (ser). but lower than the critical cutting temperature, at which it is possible to form scorches and other temperature defects on the machined surface, which reduce the quality of the machined part. This allows you to significantly increase the processing productivity of 717 det 77 without actually increasing the temperature cutting 9. At the same time, it is also possible to increase processing productivity by removing the entire allowance in one longitudinal stroke of the grinding wheel.

To ensure these grinding conditions, it is necessary to reduce the energy consumption of processing 9 by increasing the cutting capacity of the grinding wheel, by adjusting it using effective methods of mechanical action on its diamond-containing layer.

The essence of the useful model is explained by the drawing (Fig. 1), which shows a diagram illustrating the implementation of the proposed method. The processing is carried out by the periphery of the grinding wheel with a height of B made of synthetic superhard material 1 after its ruler. The grinding wheel is given a rotational movement at the speed of SR, and parts 2 - a reciprocating movement with a longitudinal feed for one revolution of the part B: (corresponding to the speed of the longitudinal feed Late)

Zo and rotational movement with the speed of Maet, which is determined by dependence (2).

The grinding depth is set within 0.1...1 mm.

An example of the implementation of the grinding method.

Processing of the periphery of a grinding wheel made of synthetic superhard material with a radius of Нр-0.15 m and a height of В-0.02 m (grit of the wheel 100/80, concentration of grains 100 95, metal connection M1-01) of a cylindrical part with a radius of Наст-0 is carried out .01 m, made of 20 x ZMWF steel, when removing an allowance equal to 0.5-103 m. Thermophysical and mechanical properties of 20 x ZMWF steel are as follows: specific heat capacity - c-549 J/kg degree); density - R -7720 kg/m3; coefficient of thermal conductivity - Х -35.6 J/(m:str.); coefficient of thermal conductivity - about -8.38-105 me/s.

Previously, after grinding the grinding wheel by the method of mechanical action on its diamond-bearing layer (by grinding with an abrasive bar), the part selected from the batch of processed parts is polished with the parameters of the cutting mode: Vi-0.01 m; Mayeti-1 m/min-0.0167 m/s; 1-0.5-1103 m; MKR-30 m/s. At the same time, the power consumed during grinding M" and idling of the machine table Mg2g are measured, which are respectively equal to: Mi-1550 W;

M2-845 W. After that, determine the effective power of grinding M-M.-M2, which is equal to

M-705 W, and determine the energy consumption of processing E according to dependence (1). As a result of the calculations, the value of З -8443-105 N/m was obtained.

Using the initial data (9 gvoo deg.; s-549 J/(kg deg.); p-7720 kg/m3; a-8.38:106 me/s;

Acre-0.15 m), the value of the maximum cutting temperature was obtained from the dependence of these layers

BO O groin -1992 degrees, and from dependence (2) the value of the speed of rotation of the part has been obtained - 2.46 m/min - 0.041 m/s.

Calculation of the speed of rotation of the Maet part according to dependence (2) should be performed as follows. First, for a given value of the 6/9 ratio, the left part of the roof is determined

Ueit|i - - and 2Ne - their dependencies. After that, the exponent of the function ex2.72 in the right-hand side of the dependence (2) is determined. From here, the speed of rotation of the Maet part is determined.

It was established by calculations that the ratio /9 tah-0.4. Therefore, in this case, it is impossible to implement a stable grinding process, in which 6/9 pitch is 1.0 (Fig. 2), and the processing performance actually does not depend on the grinding temperature. To fulfill this condition, it is necessary to significantly (by 2.5 times) reduce the energy consumption of processing C, which causes significant difficulties.

However, in this case, with a given depth of grinding I-rD? At the specified cutting temperature of 9-800 degrees, the processing productivity takes the value of 00710 det! -12.31103 mm3/min, which exceeds the machining performance values achieved in actual grinding operations under production conditions. In addition, the removal of an allowance equal to 0.5-103 m in one longitudinal stroke of the grinding wheel also allows to reduce the auxiliary processing time associated with the reversal of the machine table. This leads to an additional reduction in the time for processing this part.

The proposed useful model will provide an increase in processing productivity for a given cutting temperature.

Sources of information: 1. Zakharenko I.P. Diamond instruments and processing processes / I.P. Zakharenko. - K.:

Technology, 1980. - P. 118-119. 2. Polisher's Handbook / V.A. Kashchuk, A.B. Vereshchagin - M.: Mashinostroenie, 1988. - S.

Claims (1)

461-464. USEFUL MODEL FORMULA The method of grinding a cylindrical part, which is carried out by the periphery of a grinding wheel made of synthetic superhard material, in which the grinding wheel is driven into a rotational movement, and the part - into a rotational and reciprocating movement, while the grinding wheel is controlled by the method of mechanical action on its diamond bearing layer, which differs from the fact that, after the grinding wheel has been ruled, the part selected from the batch of processed parts is polished, the power consumed during grinding and idling of the machine table is measured, and the energy consumption of processing is determined as a function of: V. and Mdeti schi, after which the grinding of the batch of parts is carried out at the speed of rotation of the part, which is set according to the Doubleness: 8 and y28 " sweater -e and Otah de o energy intensity of processing, N/me; 717772 - effective power of grinding, W; M ; Mag. power consumed during grinding and idling of the machine table, W; m - longitudinal feed for one revolution of the part, m; det! - speed of rotation of the part selected from the batch of processed parts, m/s; depth of grinding, m; det - speed of rotation of the part, m/s; emz2.72; I - cutting temperature, degrees; tach 7 Der). maximum cutting temperature, degrees: C - specific heat capacity of the processed material, J/(kg" degrees); R. density of processed material, kg/m3; atAdDegr). coefficient of thermal conductivity of the processed material, m/s; ХМ - coefficient of thermal conductivity of the processed material, W/"m'grad.);