RU2718791C2 - Knife edge forming device - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: invention relates to application of coatings on metal surfaces by electric arc welding and can be used for machining metal surfaces of cutting tool part, in particular, forming cutting edge of knives. Knife edge forming device consists of a housing in the form of a tubular handle of variable cross section, on the surface of which a spring-loaded voltage supply button is arranged at the base attachment point and protrudes beyond the housing surface. Inside the housing there is a pulse transformer. Cathode of the conical shape of the guide is placed on the base parallel to the casing end. Cathode is connected to the DC power supply circuit of the pulse transformer. Electrodes — anodes are made in the form of wire wound on one coil, and filler material in form of wire is wound on other coils, at that both coils and guide are arranged on base.

EFFECT: technical result is simple technique of coating and obtaining required shaping of surface of coating on article, for example edge of knife.

3 cl, 3 dwg

Description

The invention relates to devices for coating metal surfaces by the method of electric arc welding and can be used to process metal surfaces of the cutting part of the tool, in particular the formation of the cutting surface of knives.

Knife edge forming devices are known (Patents No. CN 104185536 2014-12-03 B24B 3/54, No. US 2015147945 - 2015-05-28 B24B 23/40, No. JP 2017507796 (A) - 2017-03-23 B24B 3/36 ) The devices provide the formation of the edge of the knife by removing part of the material of the knife in an abrasive manner. A disadvantage of the device is a change in the geometry of the knife (its cutting edge) due to abrasive wear from the tool and operation and an increase in the time for the subsequent formation of the knife edge.

Closest to the claimed is a device for forming the edge of a knife by electric arc surfacing of the surfaces of the edges of machine parts, including knives subject to abrasive wear, described in AC 556909 V23K 9/04, containing two electrodes - an anode and a cathode connected to power circuits, a die for forced formation of edge surfaces, which allows to reduce the amount of molten base metal, improve the quality of the deposited layer and increase the wear resistance of parts.

A disadvantage of the known device is the use of hard graphite electrodes and their location on one edge surface, which does not allow to obtain the required shaping of the coating surface of the product, for example, the edge of the knife.

The problem to which the present invention is directed, is to simplify the technology of coating on the metal surface of the cutting part of the tool and obtain the required shaping of the coating surface on the product, for example, the edge of the knife while maintaining the geometry of its cutting edge during operation.

The technical result is achieved by the fact that in the device for forming the edge of the knife, containing two electrodes - an anode and a cathode connected to power circuits, a die, and also the base, in contrast to the known one, the cathode is made in the form of a guide in the form of a cone, and the die is made of V- shaped, while the electrodes - anodes are made in the form of a wire of highly conductive material wound on one coil located on both sides of the guide with the possibility of rotation and translational movement and are connected by spring-loaded current leads to the DC power circuit, and filler material in the form of a wire is wound on other coils, also located on both sides of the guide with the possibility of their rotation and translational movement, while the coils and the guide are placed on a base fixed in one case the end, while the body is made of electrical and heat-insulating material with a tubular shaping of variable cross section in the form of a handle, on the surface of which at the attachment point of the base there is also a protrusion A spring-loaded voltage supply button is behind the housing surface, and inside the housing there is a pulse transformer connected to the AC power supply via plugs and wires through a flexible input in the other end of the housing; on the base parallel to the housing end is a cathode connected to the DC power circuit of the pulse transformer and the surfacing zone is located between the guide and the V-shaped die made of superhard material.

At the same time, it is proposed to perform electrodes - anodes in the form of a highly conductive carbon fiber from carbon nanotubes.

At the same time, filler material is proposed to be made in the form of a twisted pair - a highly conductive carbon fiber from carbon nanotubes and filler wire.

The proposed device provides the ability to solve the problem, with the constructive simplicity of the device, not requiring large costs for its implementation, which is explained

FIG. 1, which shows a knife edge forming apparatus;

FIG. 2, which shows a diagram of a pulse transformer;

FIG. 3, section AA in FIG. 1, which shows a knife edge forming die.

The device consists of a housing 1 made of electrical and heat-insulating material with a tubular shaping of variable cross section in the form of a handle, on the surface of which, a spring-loaded on / off button 2 is located and protrudes beyond the housing surface, closing the circuit circuit of a pulse transformer 3, which is located in in the form of electro-radio elements - diodes 4 and throttle 5 inside the housing - handles. The pulse transformer is connected to a 220 V AC power supply via a plug 6 and wires 7 through a flexible input 8 at the end of the housing. On the other end of the casing there is a base 9, on which a cathode 10 in the form of a cone-shaped guide is placed parallel to the end of the casing, behind which there is a welding (surfacing) zone 11. Coils 12 with filler wire 13 wound on them are located on two sides of the casing highly alloyed) and coils 14 with electrodes wound on them - anodes 15 connected to the DC (welding) current supply circuit by means of spring-loaded current leads 16. A V-shaped die 17 of superhard is located behind the surfacing zone material (diamond).

The device operates as follows.

The knife to be formed by the edge is installed by the part of the edge adjacent to its handle in the guide (cathode) in the form of a cone 10, with a slight pressure of the edge on the guide. In this case (ON position), the edges of the knife edge are contacted with electrodes - anodes 14 connected by means of spring-loaded current leads 16 to the DC power circuit, and the knife walls with the ends of the coils 12 with filler wire 13. When applying AC voltage (manually closing the circuit with button 2 ) 220 V, pulse transformer 3 generates a constant (welding) current (in the absence of a transformer, a short circuit current - short circuit) is generated, by igniting the arc and the surfacing process. Simultaneously with the supply of voltage and the start of the welding process, the knife edge moves under the influence of a hand on the knife handle in the V-shaped die 17, while the deposited material from the surfacing zone 11 enters the die, which forms the knife edge. The filler wire is fed into the surfacing zone synchronously (unwinding from coils) with the knife moving. After the knife leaves the deposition zone and die 17, the circuit is opened and the circuit is opened manually duplicated by opening button 2, and the current leads and coils return to their original (open) position OFF.

The proposed device for forming the edge of the knife takes into account the following structural and technological factors:

- the amount (volume) of the deposited material corresponds to the required volume of the formed edge (performed by the correspondence of the diameter area of the filler wire to the cross-sectional area of the formed edge);

- provides rapid heating of the surface region of the substrate (knife material) by modifying its metallurgical structure, without significant heating of the underlying bulk of the substrate, followed by rapid cooling, thereby suppressing the nucleation and growth of crystals and does not phase segregation and separation of additives or components of the substrate;

- the stability of the arc burning and the deposition process is ensured by the implementation of the principle of the arrangement of arc machines for feeding the electrode or filler material at a constant speed independent of the arc voltage or any other factors and is performed by synchronizing the supply of material to the fusion zone and moving the knife rotating the ends of the coils with filler wire, at a current density of 70-85 a / mm ² and a feed speed of 5 cm / sec, which leads to a complete melting of the filler material and contributes to the process itself arc regulation in the form of an external characteristic of a power source close to a rigid I – V characteristic in an optimal mode of operation;

- power consumed for 2-3 seconds (the time the knife edge passes through the deposition zone), taking into account the required electrode section, does not exceed 0.6-0.75 kW;

- the pulse transformer circuit and the corresponding composition of electric radio elements determine the minimum necessary equipment, taking into account the possibility of placement in the volume of the body - the handle.

The device and the deposition process can be modified, taking into account the purpose and size of the tool, for example, to form the edge of the ax, the corresponding welding parameters, the corresponding diameters of the electrodes, filler wire and the corresponding die section with an angle β, which must correspond to the shape of the tool sharpening depending on the purpose tool.

When a die passes through a highly heat-conducting material (diamond), the deposited (carbon) material begins to cool, the die walls, polished to a surface roughness of 1-2 μm, form a surface with a similar roughness, which provides low friction resistance and, accordingly, easy cutting of the processed material.

The device and devices developed on its basis, for example, portable using a battery, can be used to form the cutting edge of tools for various purposes, and any housewife will appreciate the claimed device.

Claims (3)

1. A device for forming a knife edge, containing two electrodes - an anode and a cathode connected to power circuits, a die, a base and a housing, characterized in that the cathode is made in the form of a cone-shaped guide for the knife, and the die is made V-shaped from superhard material, while the electrodes - anodes are made in the form of a wire of highly conductive material wound on coils located on both sides of the guide with the possibility of their rotation and translational movement, and are connected by means of spring-loaded x current leads to the DC power circuit, and filler material in the form of a wire is wound on other coils located on both sides of the guide with the possibility of their rotation and translational movement, while the coils and the guide for the knife are placed on the base fixed in one case end, and the housing is made of electrical and heat-insulating material in the form of a tubular handle of variable cross-section, on the surface of which at the place of attachment of the base is located and protrudes beyond the surface of the housing along a spring-loaded voltage supply button, and a pulse transformer is placed inside the case for connecting to the AC power supply via plugs and wires through a flexible input at the other end of the case, while the cathode is placed on the base parallel to the case end and connected to the DC power circuit of the pulse transformer, and the knife guide and said die are placed at a distance between them equal to the surfacing zone. 2. The device for forming the edge of a knife according to claim 1, characterized in that the electrodes - anodes are made of highly conductive carbon fiber in the form of carbon nanotubes. 3. The device for forming the edge of the knife according to claim 1, characterized in that the filler material is made in the form of a twisted pair - a high-conductivity carbon fiber from carbon nanotubes and filler wire.

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