SU1355393A1 - Method and apparatus for combination dressing of abrasive wheels - Google Patents

Abstract

The invention relates to a combined straightening of circles on a metal link combining electrical and mechanical action on the working surface of a circle. The aim of the invention is to improve the productivity of the dressing, which is achieved due to the balanced removal of the circle binding by electroerosive process and the mechanical destruction of the most protruding grains from its binding, for which, during the editing process, the speed of mutual movement of the contacting surfaces of the abrasive wheel and the right tool is 0 , 5-1 m / s, and the ratio of the time of electroerosive removal of the binder and mechanical destruction of abrasive grains is 3 / 1-5 / 1. In a device that implements the method, the axis of rotation of the right roller with respect to the axis of rotation of the circle is set at an angle of 10-15 crossing, and the size of the electrode in the direction of the axis of rotation of the circle is 3-5 times larger than the size of the right roller in the same direction. . 2 sec. f-ly, 1 ill. with S (L has eaten oo soy

Description

The invention relates to a combined straightening of circles on a metal link combining electrical and mechanical action on the working surface of a circle.

The aim of the invention is to improve the editing performance by ensuring a balanced removal of the circle by the electroerosive process and the mechanical destruction of the most prominent grains from its connection.

The drawing shows a device for implementing the proposed method

The regulation of the volume of bindings removed by the EDM method and of the grains mechanically destroyed is realized in different zones of influence. VIA on the cutting surface of the circle. /

In order for the grains to fall under the mechanical action exposed from the bond, the electroerosive removal of the bond must precede the mechanical destruction.

Edit the abrasive: a circle on a metal bond only mechanically, for example, al.-. An ointment roller with relative speeds of movement of 0.5-1 m / s, when the speed of a diamond roller is less than the speed of a circle, is impossible. In this case, rolling of the working surface of the circle takes place. Therefore, it is necessary that the grains exposed from the binder fall under the mechanical action, the mechanical destruction of which at speeds of 0.5-1 m / s is very effective. In order for the destruction of the grains to be carried out by breaking out, contributing to the formation of additional cutting edges on the grains, the relative speeds of movement of the wheel and roller must be at least 0.5 m / s. Exceeding the relative speeds of displacements of more than 1 m / s leads to increased mechanical wear of the roller and, consequently, to a decrease in the mechanical destruction of the grains.

Thus, in order to implement the combined dressing method, the volume of the bond removed by the electric energy method must be large or, in extreme cases, equal to the volume of grains in this bond, taking into account the concentration of the diamond layer and the grains removed mechanically. The rates of electroerosion removal of the binder and mechanical destruction of the grains are different, therefore, the alignment of volumes removed by these methods is achieved due to the different time of electroerosion and mechanical effects. Since the speed of electroerosive removal of the binder is lower than the speed of mechanical destruction of exposed grains, the time of electroerosive removal of the binder should be 3-5 times higher than the time of mechanical destruction of the grains, i.e. the ratio of the time of electroerosion and mechanical action must be within 3/1 - 5/1. At the same time, the unbalanced with electroerosion removal of the bond, the intensification of the mechanical destruction of diamond grains, which occurs with an exposure time ratio of less than 3/1, reduces the performance of the combined dressing method, since a sharp decrease in the protrusion of the grains from the bond leads to a decrease in the chip rate, and therefore , and EDM processes that determine the performance of the combined method of dressing. An increase in the exposure time ratio of more than 5/1 also leads to a decrease in the productivity of the combined editing method, since an excessive removal of the bond leads to a greater protrusion of grains from the bond, an increase in the interelectrode gap and, accordingly, a decrease in electroerosion processes.

In order to exclude the electroerosive destruction of the area of the right-hand tool, which carries out the mechanical destruction of diamond grains, the technological current is not supplied to it.

The drawing shows a diagram of a device for the combined dressing of abrasive wheels on a metal bond by the proposed method.

The device for implementing the method consists of a power source I, connected by a negative pole to the power tool 2 installed on the table 3, which is isolated from the total mass of the machine. The positive pole of the power source 1 is connected to an abrasive circle 4 on a conductive bond through the current collector 5. The circle is isolated from the mass of the machine due to the collation of the faceplate 6.

The right tool 2 consists of an electrode 7 and an area for mechanically destroying the grains, for example, a diamond roller 8. The process current is not supplied to the diamond roller. Coolant is supplied through nozzle 9.,

- The method of the combined dressing is carried out as follows.

Before straightening, the grinding wheel is brought to the electrode 7 of the right-hand tool 2 and the diamond roller 8 is set at a distance of 0.15-0.2 mm from the surface of the wheel to be edited. This is necessary for the initial electroerosion removal of the metal ligament and the exposure of the grains before they come into contact with the diamond roller. Served through the nozzle 9 technological

medium, for example, a 3% aqueous solution of a 20 k surface grinding machine model

soda ash. The rotation of the grinding wheel 4 and the power source 1 are turned on, with the result that voltage pulses are applied to the electrode 7 of the right-hand tool 2 and the grinding wheel 4. As a result of the rotation of the circle 4 at a speed V, the vertical supply of Sg and the lateral supply of the right tool. And S, chips along the axis of the circle 7 begin to cut, which initiate electrical discharges that remove the metallic bond.

Abrasive grains are exposed.

I

on the cutting surface of the circle.

After the total vertical flow reaches 0.15-0.2 mm, a diamond roller 8 comes into contact with the cutting surface of the wheel, which begins to rotate with speed. The relative speeds of movement of the surfaces of the circle and the roller are 0.5-1 m / s and are realized, for example, by crossing the axes of the grinding wheel and the roller (the crossing angle to obtain the indicated relative speeds of the calculations is 10-15)

Upon further movement of the circle in the direction of vertical feed, mechanical destruction of the exposed grains begins. In order to keep the volumes of mechanical destruction of the grains and electroerosive removal of the binder in the future, the time of electroerosive straightening should be 3-5 times higher than the time of mechanical destruction of the grains. The latter is achieved due to the fact that

type 7 in the direction of transverse feeding exceeds the size of the diamond roller in the same direction by 3-5 times.

As a result of the balanced removal of metallic svokki and mechanical destruction of grains in the interelectrode gap, conditions are created that facilitate the flow of working pulses and reduce the number of idle pulses of 1 our short-circuit pulses, which do not perform useful work on removing the metal ligament. At the same time, the editing performance is improved.

An example of a combined method of dressing a 1A1 250x x15x76x5AC6 I60 / 125-4-MI grinding wheel on a modernized electrical eroded right

No. 71

The right tool: electrode - copper bar 40x30x40 mm (30 mm in direction S); diamond roller - 1A1 circle 40x10x16x5 AC15 315 / 250-4-М1. The initial gap between the surface of the roller and the grinding wheel is 0.2 mm. The working fluid is a 3% aqueous solution of soda ash. The power source is a source of technological current model ITT-35.

Mechanical modes: grinding wheel speed V f 35 m / s; vertical feed Sg 0.005 mm / stroke, transverse feed S p m / min; the relative circumferential speed of movement of the surfaces of the roller and the grinding wheel is 0.5 m / s.

Electrical modes: Idling amplitude voltage 1 60Bj pulse frequency f 50 Hz.

The negative power supply half power is connected to the power supply part of the right-hand tool, positively to the AC 160 / 125-4-M grinding wheel. The ratio of the time of electroerosive removal of the bond to the time of mechanical destruction of the grains is 3/1.

55

Combined method of editing on the specified modes, o, ensured the performance of 206 (and ZV: 1 18A).

The performance of the contact-electroerosive straightening, taken as the base object, using a copper electrode with dimensions

five . one

40x30x40 mm was 120 (and, p 2.8 V, 1er 15A).

Mechanical editing (grinding) with the use of a diamond roller cannot be realized, since rolling of the working surface of the wheel, accompanied by vibrations, occurs.

Thus, the proposed combining method of straightening is equal to the productivity of editing by 1.7 times as compared with the contact-electroerosion method and 2.9 times as compared with the prototype, in which the conductive metalloabrasive circle is used by the electrode.

F. formula

1. A method of combined dressing of abrasive wheels on a metal bond, in which electrically act on the wheel link and mechanically destroy grains in various zones at various relative speeds of the surface of the circle and surfaces of the right tool and electric tool 553936

yes, in order to increase the productivity of the dressing, they support (- during the process, the speed of mutual movement of the contacting surfaces of the abrasive wheel and the right tool is 0.5-1 m / s, and the ratio of the electroerosion time - 10 ° binder removal, and mechanical

destruction of abrasive grains 3/1 -5/1.

2. A device for combined dressing of abrasive wheels on a metal bond, containing an isolated table, on which the right roller is mounted on the axis and an electrode; the power source connected to the current supply on the axis of the circle and the electrode, as well as the coolant supply circuit, is due to the fact that, with the aim of increasing the efficiency of the roller, the rotational axis of the roller with respect to to the axis of rotation of the circle is set at an angle

fastenings are 10-15 °, and the electrode size in the direction of the axis of rotation of the circle is 3-5 times larger than the size of the right roller in the same direction.

Editor M.Kelemes

Compiled by B. Kuznetsov Tehred M. Didyk

Order 5744/13 Circulation 970 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

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Production and printing company, Uzhgorod, st. Project, 4

Proofreader L. Patay

Claims (2)

Claim 1. A method of combined dressing of abrasive wheels on a metal bond, in which they electrically act on the bond of the wheel and mechanically destroy zeria in different zones at different relative speeds of the surface of the wheel and the surface of the ruling tool and the electrode tool, characterized in that, with In order to increase the productivity of dressing, during the process, they support the speed of mutual movement of the contacting surfaces of the abrasive wheel and the ruling tool, equal to 0.5-1 m / s, and the ratio belts of electroerosive removal of a ligament. and mechanical destruction of abrasive grains 3/1 -5/1. 2. A device for the combined editing of abrasive wheels on a metal bond, comprising an insulated table on which a steering roller is mounted on an axis and an electrode; a power source connected to the current supply on the axis of the circle and the electrode, as well as the coolant supply system, which is due to the fact that, with a view to higher: to improve dressing performance, the axis of rotation of the roller relative to the axis of rotation the circle is set at a cross angle of 10-15 °, and the size of the electrode in the direction of the axis of rotation of the circle is 3-5 times larger than the size of the ruling roller in the same direction.