RU2514238C1 - Electromechanical reconditioning of parts - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: part surface is upset to make grooves thereon and upset sections are levelled. Circular grooves on part surface feature pitch K=0.5…2 mm to make seal of labyrinth type. Circular grooves upset and upset section levelling are performed synchronously at NC machine. Said NC machine has separate system of tool drives to allow automatic displacement of upset and level tools relative to machined part. Note here that levelling tool is delayed relative to upset tool by magnitude equal to 1-2 steps K between said grooves.

EFFECT: higher efficiency of reconditioning and hardening, tight relief of part surface.

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Description

The invention relates to the field of metalworking of machine parts, relates to methods for increasing the durability of various parts during their restoration by operations of electromechanical upsetting and smoothing.

Known methods for restoring precision parts (Reliability and machine repair / V.V. Kurchatkin, N.F. Telnov,

K.A. Achkasov et al .; under the editorship of V.V. Kurchatkina. - M .: Kolos, 2000. - 776 p.) By applying the methods of galvanic chromium plating, diffusion metallization, hot plastic deformation, detonation-gas spraying, etc., which contribute to the increase in the size of parts.

The disadvantages of these methods are: duration; the complexity of the processes and the high cost of energy and components; low adhesion of coatings to the base, which leads to low wear resistance of parts and their high cost.

A known method of restoring the surfaces of machine parts (Askinazi BM, Hardening and restoration of parts by electromechanical processing. - 3rd ed., Moscow: Mashinostroenie, 1989. - 200 p.) By electromechanical planting of a worn surface and subsequent electromechanical smoothing. During processing in this way, a current of high force and low voltage passes through the contact point of the tool with the product moving along a helical line with a supply of 0.1 ... 3 mm / rev, as a result of which the surface of the product in this section is subjected to strong heating, under deformation of the tool and the surface layer of metal is hardened. This method significantly changes the physicomechanical properties of the surface layer and improves the product performance. The fundamental difference between upsetting and smoothing is the difference in contact stresses. Disembarkation is performed by a tool, the width of the contact surface of which is numerically less than three times the feed (a roller or plate with an angle at the apex of 60 °, moving in increments of 1-3 mm / rev). In the second case, the processing is carried out by a tool whose contact width is significantly greater than the feed (a roller or a plate with a radius at the apex of 60 mm, moving in increments of 0.1-0.3 mm / rev).

This method allows you to more effectively increase the size of the parts due to the redistribution of the metal surface with a simultaneous increase in its hardness.

The disadvantage of this method is the helical nature of the redistribution of metal on the shafts, which does not provide the proper tightness of precision mates.

There is also a method of electromechanical restoration of parts of precision mates (RF Patent No. 2459694) by electromechanical surface upsetting with the formation of annular grooves on it and subsequent electromechanical smoothing of the planted areas by simultaneous heating of the surface layer of the part (adopted as a prototype). A feature of this method is that the grooves on the surface of the part are annular with a pitch of 0.5 ... 2 mm, creating a kind of labyrinth seal.

The disadvantages of this method are:

- insufficiently high productivity of the process due to the sequential (sequential) performance of the upsetting and smoothing operations, as well as the complexity of manual tuning and the complexity of control to ensure a given step of upsetting grooves;

- significant loss of electricity in the part due to the alternate performance of the operations of landing and smoothing, which leads to cooling of the surface between operations and re-heating of the part during the smoothing operation.

The technical result of the invention is a further increase in the efficiency of the process of electromechanical restoration of parts by increasing processing productivity and increasing the efficiency of the process.

The specified technical result is achieved by the fact that the operations of upsetting the annular grooves and smoothing the surface of the part are carried out synchronously on a machine tool with a programmed control having a separate system of drives for moving tools, which according to the program provide automatic independent from each other movement of upsetting and smoothing tools relative to the workpiece and an almost constant value delay (lag) of the smoothing tool in relation to the planting, equal to 1 ... 2 step Am “K” between the grooves on the part.

The drawing shows a simplified diagram of the proposed processing method.

The method of electromechanical restoration of a part is as follows. On a machine with a CNC system, which has separate drive drives for the executive bodies (calipers), onto which the upsetting and smoothing tools are fixed, electrically connected to each other. The restored part is fixed on the spindle of the machine and provide an electric current supply to it, creating a circuit of the electric circuit. According to the corresponding program, on the switched-on machine, the operation of annular grooving of the annular grooves with tool 2 on the surface of part 1 with a diameter of D ₀ along a predetermined path is performed (introducing tool 2 to a given depth with a force P ₁ , with a pitch of K = 0.5 ... 2 mm to diameter D ₁ - its retraction - moving along the surface of the part for a given step - repeating the cycle) and the operation of smoothing the formed annular protruding sections with tool 3 with a force P ₂ , supply s = 0.1 ... 0.3 mm to diameter D ₂ , and smoothing tool 3 rel rel regarding part 1 with a lag value relative to the planting tool 2 equal to 1 ... 2 steps "K" between the grooves on part 1, as a result of which the combs (not shown in the drawing) on the surface of part 1 after landing do not have time to cool significantly, which opens the ability to set the minimum energy-intensive modes of the EMO process when performing a part recovery operation.

Thus, when using this method of restoring parts on the surface of the part, a finally hardened planted surface with regular annular grooves and the required value of hardness is formed. In addition, the processing productivity is increased, unproductive losses of electric energy are reduced during the process.

Claims (1)

A method for electromechanical restoration of a precision mating part, including electromechanical surface upsetting with the formation of grooves on it and electromechanical smoothing of the planted surface sections by simultaneous heating of the surface layer of the part by passing electric current through the contact area of the smoothing tool with the part and mechanical impact of the said tool on it, the surface of the part is performed annular with a step of K = 0.5 ... 2 mm with the creation of a seal along another labyrinth seal, characterized in that the operations of upsetting annular grooves and smoothing the planted areas are carried out synchronously on a machine tool with a programmed control having a separate system of drives for moving tools to automatically move the planting and smoothing tools relative to the workpiece and the delay value of the lag of the smoothing tool relative to planting, equal to 1 ... 2 steps K between the mentioned grooves on the part.

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