WO2019204979A1

WO2019204979A1 - Device and method for preparing surface strengthening coating

Info

Publication number: WO2019204979A1
Application number: PCT/CN2018/084234
Authority: WO
Inventors: 赵航; 伍晓宇; 徐斌; 梁雄; 雷建国; 鲁艳军; 刘宇丰
Original assignee: 深圳大学
Priority date: 2018-04-24
Filing date: 2018-04-24
Publication date: 2019-10-31
Also published as: CN108699703A; CN108699703B

Abstract

A device for preparing a surface strengthening coating, comprising a displacement platform (1), an electrode fixture (4), a sheet electrode (6), a coating (7), a workpiece fixture (10), and an electrical discharge machining power source (11). A positive electrode of the electrical discharge machining power source (11) is electrically connected to the electrode fixture (4), and a negative electrode thereof is electrically connected to the workpiece fixture (10). The coating (7) is provided on a surface of the electrode. When the electrical discharge machining power supply (11) is turned on, the displacement platform (1) drives the sheet electrode (6) held by the electrode fixture (4) to move, and the sheet electrode (6) processes a surface to be processed (9) of the workpiece (8), and forms a strengthening coating on said surface (9), so as to improve surface properties, reduce surface wear, and increase the service life thereof. Compared with conventional energy beam coating, PVD, thermal spraying, and other coating technologies; the device and method for preparing a surface strengthening coating can be adopted to carry out processing of inner surfaces of small structures, such as narrow slits and small holes, and is particularly applicable to hot extrusion dies for aluminum alloy profiles.

Description

Device and method for preparing surface strengthening coating

Technical field

The invention belongs to the technical field of coating processing, and more particularly to a device and a method for preparing a surface strengthening coating.

Background technique

Aluminum profiles are lightweight, low-cost, recyclable, and are widely used in construction, power, automotive, electronics and mechanical equipment. With the continuous development of the social economy, the global aluminum profile market demand has increased year by year, and it has also driven the rapid growth of the aluminum processing industry. Under this fierce competition in the industry, all enterprises have increased the cost control, and under the premise of ensuring the quality of production, try to reduce the production cost. Extrusion mold is an important tool for the production of aluminum profiles, and it is also a consumable in production. The performance, maintenance cost and service life of the mold will directly affect the product quality and production cost. In the case of extrusion dies, the sizing belt, that is, the surface of the working belt is subjected to high temperature, high load and high extrusion speed during service, so it is extremely easy to wear. It can be said that the surface properties and state of the working belt directly affect the mold. Performance and service life. How to strengthen the surface properties of the extrusion die working belt and enhance its hardness and wear resistance are the key factors to improve the service life of the mold and reduce the production cost.

At present, mold manufacturing companies mainly use surface nitriding technology to improve the surface properties of extrusion dies. There are three main types of nitriding technology: liquid nitriding, gaseous nitriding and ion nitriding, in which liquid nitriding causes environmental problems; although the gaseous nitriding method is more environmentally friendly, it produces a relatively thick nitride layer. It is easy to reduce the strength of the mold; ion nitriding is not conducive to the processing of the slot structure in the extrusion die. In addition, the nitride layer produced by the nitriding technique gradually disappears as the temperature increases, and the strengthening effect is lost. Not only that, the nitriding technology uses only the nitriding principle to form nitrides in the alloy material to improve the surface properties of the alloy material. Although it can effectively strengthen the overall surface properties of the mold, it is difficult to meet the needs of local areas, especially work belts. The specially strengthened surface area is targeted, and because the strengthening method is relatively simple, the enhancement of the surface of the material is relatively limited.

Coating technology is an important method to improve the surface properties of materials. The coating technology can not only improve the surface properties of the substrate, but also can introduce coating materials with special properties, such as ceramic particles, solid self-lubricants, alloying elements, etc. into the substrate, and can also obtain high-performance surfaces for inexpensive metals. Therefore, in the mold manufacturing industry, coating techniques such as laser cladding/alloying, arc surfacing, plasma beam cladding/alloying, and PVD (physical vapor deposition) have been widely used to enhance mold surface properties. However, these techniques are based on the method of directly irradiating or sputtering the surface to be processed with an energy beam, and it is difficult to manufacture a hot extrusion die, especially a mold having a slit or a work belt inside. At present, it can be applied to the coating technology of hot extrusion die making, mainly CVD (Chemical Vapor Deposition) technology. The coating produced by CVD technology has the function of reducing the friction between aluminum and the mold and reducing the wear of the extrusion die. CVD technology has disadvantages such as high manufacturing cost, low efficiency, polluted environment, etc., and the processing temperature is high, which easily affects the overall size, shape and material properties of the mold, so it is relatively less practical in the industry.

technical problem

It is an object of the present invention to provide an apparatus and method for preparing a surface-strengthening coating to solve the technical problem that it is difficult to coat a surface of a fine structure such as a slit or a small hole in the prior art.

Technical solution

In order to achieve the above object, the technical solution adopted by the present invention is to provide a device for preparing a surface strengthening coating, comprising:

Displacement platform

An electrode fixture mounted to the displacement platform and driven to move by the displacement platform;

a sheet electrode held by the electrode holder;

a workpiece holder for fixing a workpiece;

a coating provided on a surface of the sheet electrode;

An electric discharge machining power source having a positive electrode and a negative electrode, the positive electrode being electrically connected to the electrode holder, and the negative electrode being electrically connected to the workpiece holder.

Further, the number of the electrode holders is two, and the two electrode holders are spaced apart, and the two electrode holders simultaneously clamp the sheet electrodes.

Further, the electrode fixture is connected with an anode terminal, and the anode and the anode terminal are electrically connected by an anode cable.

Further, the workpiece holder is connected with a cathode terminal, and the negative electrode and the cathode terminal are electrically connected by a cathode cable.

Further, the normal direction of the surface to be processed of the workpiece is perpendicular to the horizontal plane, and the plane of the sheet electrode is parallel to the horizontal plane.

Further, the workpiece has a slit, and a surface to be processed of the workpiece is an inner surface of the slit, and the sheet electrode is disposed in the slit.

Further, the workpiece is a hot extrusion die having a work belt, the surface to be processed of the workpiece is an inner surface of the work tape, and the chip electrode is disposed through the work tape.

Further, the sheet electrode is a copper electrode.

Further, the thickness of the coating ranges from 0.1 mm to 0.2 mm.

The invention provides a preparation method of a surface strengthening coating, which comprises the above apparatus for preparing a surface strengthening coating, and the preparation method of the surface strengthening coating comprises the following steps:

S10) preparing a coating; preparing a sheet electrode, attaching the coating to a surface of the sheet electrode; clamping the workpiece to the workpiece holder;

S20) clamping the sheet electrode to the electrode holder to straighten the sheet electrode, and controlling the displacement platform such that the sheet electrode is close to a surface to be processed of the workpiece, and then the sheet is The electrode is raised to the working distance;

S30) setting electrical discharge machining parameters;

S40) Performing a spark discharge deposition process on the surface to be processed of the workpiece, the displacement platform driving the sheet electrode to move relative to the surface to be processed of the workpiece during processing.

Further, the coating layer is formed by mixing a submicron particle size powder containing ceramic, metal or alloy as a main component and a conductive paste.

Further, in step S40), the surface to be processed of the workpiece is subjected to a spark discharge deposition process under the protection of an inert gas.

Further, in step S40), the displacement platform drives the sheet electrode to be horizontally moved along the length or width direction of the sheet electrode relative to the workpiece to be processed during processing; or the displacement platform is The sheet electrode is driven to reciprocate relative to the surface to be processed of the workpiece during processing.

Further, after step S40), step S50) is further included to clean the surface to be processed of the processed workpiece.

Further, after step S50), step S60) is further included to finish the workpiece.

Beneficial effect

The positive electrode of the electric discharge machining power source is electrically connected to the electrode holder, and the negative electrode is electrically connected to the workpiece holder, and the surface of the electrode is provided with a coating. When the EDM power supply is turned on, the displacement platform drives the sheet electrode held by the electrode holder to move, the sheet electrode processes the surface to be processed of the workpiece, and forms a strengthening coating on the surface to be processed to improve surface performance and reduce Surface wear and improve service life. Compared with the conventional energy beam coating, PVD, thermal spraying and other coating technologies, the surface strengthening coating coating preparation device and method can implement the inner surface processing of small structures such as narrow slits and small holes, especially for aluminum alloy profiles. Hot extrusion dies are more suitable.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments or the description of the prior art will be briefly described below. It is obvious that the drawings in the following description are only the present invention. For some embodiments, other drawings may be obtained from those of ordinary skill in the art in light of the inventive workability.

1 is a schematic structural view of an apparatus for preparing a surface strengthening coating according to an embodiment of the present invention;

Figure 2 is a front elevational view of the workpiece machined by the apparatus for preparing a surface-strengthening coating of Figure 1;

Figure 3 is a cross-sectional view of the workpiece of Figure 2 taken along line A-A;

Figure 4 is an enlarged schematic view of the working belt of the workpiece of Figure 2;

Fig. 5 is a schematic view showing the structure of a sheet electrode used in the apparatus for producing a surface-strengthening coating of Fig. 1.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It is to be noted that when an element is referred to as being "fixed" or "in" another element, it can be directly on the other element or indirectly. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or indirectly connected to the other element.

It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top" The orientation or positional relationship of the "bottom", "inside", "outside" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for the convenience of describing the present invention and simplifying the description, and does not indicate or imply the indicated device. Or the components must have a particular orientation, are constructed and operated in a particular orientation, and thus are not to be construed as limiting the invention.

Referring to Fig. 1, a device for preparing a surface strengthening coating provided by the present invention will be described first. A device for preparing a surface strengthening coating, comprising a displacement platform 1, an electrode holder 4 mounted on the displacement platform 1 and driven to move by the displacement platform 1, a sheet electrode 6 held by the electrode holder 4, and a workpiece holder for fixing the workpiece 8. 10. A coating 7 provided on the surface of the sheet electrode 6, and an electric discharge machining power source 11 having a positive electrode and a negative electrode, the positive electrode is electrically connected to the electrode holder 4, and the negative electrode is electrically connected to the workpiece holder 10.

The positive electrode of the electric discharge machining power source 11 is electrically connected to the electrode holder 4, the negative electrode is electrically connected to the workpiece holder 10, and the surface of the electrode is provided with a coating 7. When the electric discharge machining power source 11 is turned on, the displacement platform 1 drives the sheet electrode 6 held by the electrode holder 4 to move, and the sheet electrode 6 processes the surface to be processed of the workpiece 8, and forms a reinforced coating on the surface 9 to be processed. To improve surface properties, reduce surface wear and improve service life.

Compared with conventional energy beam (laser, electron beam, plasma beam, arc) coating, PVD, thermal spraying and other coating technologies, the coating preparation device for surface strengthening coating can implement narrow structures such as narrow slits and small holes. Surface processing, especially for aluminum alloy hot extrusion die.

Compared with the CVD process, the surface-enhanced coating preparation device has higher processing efficiency, relatively friendly environment, no workpiece thermal distortion, and more flexible process, and the coating 7 obtained has a wider application range;

Compared with the conventional nitriding process, the coating preparation device for the surface strengthening coating can obtain a functional surface with superior performance by adjusting the composition and ratio of the coating powder, and has a wide selection of materials and a higher process flexibility;

Compared with nitriding technology and CVD technology, the coating preparation device for surface strengthening coating can selectively strengthen the local area of the mold, which is more targeted and consumes less energy;

EDM equipment and processes are relatively mature, and equipment and manufacturing costs are lower than other surface coating processing technologies.

The sheet electrode 6 is a sheet electrode or a foil structure electrode, and both surfaces of the sheet electrode 6 are coated with a coating layer 7 for performing electric spark discharge electric discharge machining on the surface 9 of the workpiece 8 to be processed.

The displacement platform 1 is an XYZ displacement platform, and is provided with driving members in three directions, which can drive the displacement platform 1 to move to a predetermined position in the space.

Further, as a specific embodiment of the apparatus for preparing a surface strengthening coating provided by the present invention, the number of the electrode holders 4 is two, the two electrode holders 4 are spaced apart, and the two electrode holders 4 simultaneously hold the sheet electrodes. 6. Both end portions of the sheet electrode 6 are respectively held by one electrode holder 4, so that the sheet electrode 6 is stretched and straightened. When the displacement stage 1 drives the electrode holder 4, the sheet electrode 6 can move smoothly.

Further, as a specific embodiment of the apparatus for preparing a surface-strengthening coating provided by the present invention, the electrode holder 4 is connected with the anode terminal 2, and the anode and the anode terminal 2 are electrically connected by the anode cable 12. The anode terminal 2 on the electrode holder 4 is connected to the positive electrode of the electric discharge machining power source 11 through the anode cable 12, and the structure is easy to assemble.

Further, as a specific embodiment of the apparatus for preparing a surface strengthening coating provided by the present invention, the workpiece holder 10 is connected with a cathode terminal 3, and the cathode and the cathode terminal 3 are electrically connected by a cathode cable 13. The cathode terminal 3 on the workpiece holder 10 is connected to the negative electrode of the electric discharge machining power source 11 through a cathode cable 13, and the structure is easy to assemble.

Further, as a specific embodiment of the apparatus for preparing a surface strengthening coating provided by the present invention, the normal direction of the surface 9 of the workpiece 8 to be processed is perpendicular to the horizontal surface, and the plane of the sheet electrode 6 is parallel to the horizontal plane. This structure facilitates the sheet electrode 6 to perform EDM plasma discharge machining on the surface 9 to be processed of the workpiece 8.

Further, as a specific embodiment of the apparatus for preparing a surface-strengthening coating provided by the present invention, the workpiece 8 has a slit, and the surface 9 to be processed of the workpiece 8 is an inner surface of the slit, and the sheet-like electrode 6 is bored in the slit. A coating 7 is applied to the inner surface of a fine structure (narrow slit, small hole, etc.).

Further, as a specific embodiment of the apparatus for preparing a surface strengthening coating provided by the present invention, the workpiece 8 is a hot extrusion die having a working belt, and the surface 9 to be processed of the workpiece 8 is an inner surface of the working belt, and is in the form of a sheet. The electrode 6 is threaded through the work belt. The surface strengthening of the working strip of the aluminum alloy profile hot extrusion die is realized to improve the surface performance of the mold working belt, reduce the surface wear and improve the service life of the mold.

Further, as a specific embodiment of the apparatus for preparing a surface strengthening coating provided by the present invention, the sheet electrode 6 is a copper electrode. This structure facilitates the sheet electrode 6 to perform electric discharge discharge discharge processing on the surface 9 to be processed of the workpiece 8.

Further, as a specific embodiment of the apparatus for preparing a surface-strengthening coating provided by the present invention, the thickness of the coating layer 7 ranges from 0.1 mm to 0.2 mm. This structure facilitates the sheet electrode 6 to perform EDM plasma discharge machining on the surface 9 to be processed of the workpiece 8, and forms a surface strengthening coating on the surface 9 to be processed of the workpiece 8.

The invention also provides a preparation method of the surface strengthening coating, which adopts the preparation device of the surface strengthening coating layer of any of the above embodiments, and the preparation method of the surface strengthening coating layer comprises the following steps:

S10) preparing the coating 7, according to the strengthening requirements of the workpiece 8, the working conditions and the like, selecting a suitable coating material composition and ratio of the coating material 7, and mixing it by ball milling, stirring, alloying, etc.;

Preparing the sheet electrode 6, according to the structural shape of the workpiece 8, selecting a thin copper plate or copper foil of a suitable thickness and width, and processing it to a shape and size suitable for the structure of the workpiece 9 to be processed 9; by coating, bonding, heat The prepared coating layer 7 is attached to the surface of the sheet electrode 6 by spraying or the like, and the thickness is determined according to factors such as the structure of the workpiece 8, the thickness of the deposited coating layer 7, the parameters of the electric spark deposition process, and the like;

The clamping and positioning of the workpiece 8 to be processed, the workpiece 8 to be processed is clamped on the workpiece holder 10 of the electric discharge machine, and the surface 9 to be processed is vertically upward.

S20) Clamping and tool setting of the sheet electrode 6. The prepared sheet electrode 6 is clamped on the electrode holder 4, and the distance of the electrode holder 4 is adjusted to straighten the sheet electrode 6; the displacement platform 1 is controlled so that the sheet electrode 6 is slowly brought close to the workpiece 8 after the clamping The processing surface 9 completes the tool setting process; after the tool setting is completed, the sheet electrode 6 is slightly raised to the working distance.

S30) Set the EDM parameters, and set the EDM process parameters, including current, voltage, pulse frequency, etc. according to the processing requirements.

S40) according to the set process parameters, start the power switch, start the electric spark deposition process, perform the spark discharge deposition process on the surface 9 to be processed of the workpiece 8, and the displacement platform 1 drives the chip electrode 6 relative to the workpiece during the processing. The surface to be processed 9 of 8 is constantly moving at a constant speed. On the one hand, the coating 7 on the sheet electrode 6 is uniformly consumed, and on the other hand the deposition of the coating on the surface 9 to be processed of the workpiece 8 is more uniform.

Compared with conventional energy beam (laser, electron beam, plasma beam, arc) coating, PVD, thermal spraying and other coating technologies, the coating preparation device and method for surface strengthening coating can implement fine structures such as narrow slits and small holes. The inner surface processing is especially suitable for aluminum alloy hot extrusion die.

Compared with the CVD process, the surface-enhanced coating coating preparation device and method have higher processing efficiency, relatively friendly environment, no workpiece thermal distortion, and more flexible process, and the coating 7 obtained has a wider application range;

Compared with the conventional nitriding process, the coating preparation device and method for surface strengthening coating can obtain a functional surface with superior performance by adjusting the composition and ratio of the coating powder, and the material selection range is wide, and the process flexibility is higher;

Compared with nitriding technology and CVD technology, the surface strengthening coating coating preparation device and method can selectively strengthen the local area of the mold, and have stronger specificity and lower energy consumption;

Further, as a specific embodiment of the preparation method of the surface strengthening coating provided by the present invention, the coating layer 7 is formed by mixing a submicron particle size powder and a conductive paste mainly composed of ceramics, metals or alloys. The coating 7 formed by this solution can form a reinforced coating on the surface 9 to be processed of the workpiece 8 to improve the surface properties. The alloy is a high performance alloy. The submicron particle size powder may be one or more of WC, Co, Ti, TiC, SiC, Ni, etc., which are formulated as needed.

Further, as a specific embodiment of the method for preparing the surface strengthening coating provided by the present invention, in step S40), the surface 9 to be processed of the workpiece 8 is electrically protected under the protection of nitrogen, argon or other inert gas. Spark discharge deposition processing can improve the processing quality.

Further, as a specific embodiment of the method for preparing the surface strengthening coating provided by the present invention, in step S40), the displacement platform 1 drives the sheet electrode 6 to be processed relative to the surface 9 to be processed of the workpiece 8 during processing. The length or width direction of the electrode 6 is horizontally moved, and is suitable for the case where the width of the workpiece 8 to be processed is large, and the electric discharge discharge deposition processing of the surface 9 to be processed is realized; or the displacement platform 1 drives the sheet electrode 6 during processing. The upper and lower reciprocating movements of the surface 9 to be processed relative to the workpiece 8 are suitable for the case where the width of the workpiece 8 to be processed is small, and the electric discharge discharge deposition processing of the surface 9 to be processed is realized.

Further, as a specific embodiment of the method for preparing the surface-strengthening coating provided by the present invention, after step S40), step S50) is further included, and the surface 9 to be processed of the processed workpiece 8 is cleaned to remove the electric spark. Carbon deposits, debris, etc. generated during the deposition process.

Further, as a specific embodiment of the method for preparing the surface strengthening coating provided by the present invention, after step S50), the step S60) is further included to finish the workpiece 8. The cleaned workpiece 8 is finished according to the production needs, including grinding, polishing, etc., to meet the production requirements.

The apparatus and method for preparing the surface strengthening coating of the present invention are described in detail by taking the case of processing the right angle aluminum profile hot extrusion die shown in FIG. 2 and FIG. 3 as an example. The mold structure is shown in Figure 2 and Figure 3. The working belt structure is a narrow slit structure, and the narrow slit width is designed to be 1.5. Mm, the working belt outer wall length L is 50×50 mm, the inner wall length is 48.5×48.5 mm, the working belt working surface width W is 5 mm, and the overall thickness of the mold is 60 mm. The enlarged view of the work tape and the area where the coating needs to be processed are shown in Fig. 4. The mold has six coated surfaces of A, B, C, D, E, and F. The specific processing of the coating on each processed surface is as follows:

S10) uniformly mixing the submicron particle size powders of WC, Co, and Ti according to a volume ratio of 4:2:4, and mixing the conductive paste as a coating material;

According to parameters such as a slit width of 1.5 mm, a total die thickness of 60 mm, and a working belt length, a thin copper plate having a thickness of 0.8 mm was selected as the sheet electrode 6, and the size was cut into 120 mm × 20 mm and 80 mm × 1.5. Two sets of sheet electrodes 6 of mm; the prepared coating material is uniformly sprayed on both surfaces of the prepared sheet-like electrode 6 to form a coating layer 7 having a thickness of 0.1 mm;

The mold is clamped on the electric discharge machine, and the processing surface A is selected as the first processing surface, and the normal direction thereof is perpendicular to the horizontal surface;

S20) passing the prepared sheet electrode (size 120 mm×20 mm) through the slit of the mold working belt, and clamping both ends thereof on the electrode holder 4, and adjusting the distance of the electrode holder 4 to straighten the sheet electrode 6 Driving the displacement platform 1 so that the coated surface of the sheet electrode 6 gradually approaches the surface 9 to be processed of the mold working belt, stops when a short circuit alarm is heard, and sets a zero point, and then drives the sheet electrode 6 away from the surface to be processed 9 by a certain distance;

S30) Set the spark deposition processing parameters to current: 10A, voltage: 100V, pulse frequency: 2000Hz, shielding gas (nitrogen) flow: 8 L/min, electrode moving speed 10 mm/min, electrode moving direction: along working belt length The direction moves horizontally;

S40) turning on the electric discharge machining power source 11 and performing electric spark deposition processing until the outer wall of the working belt is processed;

S41) After the step S40) is completed, the sheet electrode 6 is detached, the mold is rotated by 90° to the processing surface B, and the steps S20) to S40) are repeated until the other processing surface is finished, wherein it is noted that the sheet electrode 6 pairs of processing surface B processing position 6b need to be staggered to the position 6a of the electrode used in the processing surface A, as shown in Figure 5, the sheet electrode 6 has a clamping portion 61 at both ends;

S42) repeating steps S20) to S40) to complete processing of the processed surfaces C, D;

S43) Replacing the chip electrode (size 80 mm × 1.5 mm), repeating steps S20) to S40), completing the processing of the processing surface E, wherein it is noted that the sheet electrode 6 does not need to be horizontally moved during the processing. Reciprocating up and down;

S44) repeating step S43), completing the processing of the processing surface F, and finally processing the coating 7 on all the processing surfaces on the working belt of the mold;

S50) cleaning the mold after processing to remove the processing residue;

S60) Grinding and polishing the mold working belt coating 7 until it meets the production requirements.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A device for preparing a surface strengthening coating, comprising:

Displacement platform

An electrode fixture mounted to the displacement platform and driven to move by the displacement platform;

a sheet electrode held by the electrode holder;

a workpiece holder for fixing a workpiece;

a coating provided on a surface of the sheet electrode;

An electric discharge machining power source having a positive electrode and a negative electrode, the positive electrode being electrically connected to the electrode holder, and the negative electrode being electrically connected to the workpiece holder.
The apparatus for preparing a surface strengthening coating according to claim 1, wherein the number of the electrode holders is two, and the two electrode holders are spaced apart, and the two electrode holders simultaneously hold the sheets. Electrode.
The apparatus for preparing a surface-strengthening coating according to claim 1, wherein the electrode holder is connected with an anode terminal, and the positive electrode and the anode terminal are electrically connected by an anode cable.
The apparatus for preparing a surface-strengthening coating according to claim 1, wherein the workpiece holder is connected with a cathode post, and the negative electrode and the cathode post are electrically connected by a cathode cable.
The apparatus for preparing a surface-strengthening coating according to claim 1, wherein a normal direction of the surface to be processed of the workpiece is perpendicular to a horizontal plane, and a plane of the sheet-like electrode is parallel to a horizontal plane.
The apparatus for preparing a surface strengthening coating according to any one of claims 1 to 5, wherein the workpiece has a slit, and a surface to be processed of the workpiece is an inner surface of the slit, the sheet electrode Wear through the gap.
The apparatus for preparing a surface-strengthening coating according to any one of claims 1 to 5, wherein the workpiece is a hot extrusion die having a work belt, and the surface to be processed of the workpiece is the work belt An inner surface, the sheet electrode is disposed through the working tape.
The apparatus for producing a surface-strengthening coating according to any one of claims 1 to 5, wherein the sheet electrode is a copper electrode.
The apparatus for producing a surface-strengthening coating according to any one of claims 1 to 5, wherein the coating has a thickness ranging from 0.1 mm to 0.2 mm.
A method of preparing a surface-strengthening coating, comprising the apparatus for preparing a surface-strengthening coating according to any one of claims 1 to 9, wherein the method for preparing the surface-strengthening coating comprises the following steps:

S10) preparing a coating; preparing a sheet electrode, attaching the coating to a surface of the sheet electrode; clamping the workpiece to the workpiece holder;

S20) clamping the sheet electrode to the electrode holder to straighten the sheet electrode, and controlling the displacement platform such that the sheet electrode is close to a surface to be processed of the workpiece, and then the sheet is The electrode is raised to the working distance;

S30) setting electrical discharge machining parameters;

S40) Performing a spark discharge deposition process on the surface to be processed of the workpiece, the displacement platform driving the sheet electrode to move relative to the surface to be processed of the workpiece during processing.
The method of preparing a surface-strengthening coating according to claim 10, wherein the coating layer is formed by mixing a submicron-sized powder having a ceramic, a metal or an alloy as a main component and a conductive paste.
The method of preparing a surface-strengthening coating according to claim 10, wherein in step S40), the surface to be processed of the workpiece is subjected to a spark discharge deposition process under inert gas protection.
The method of preparing a surface-strengthening coating according to claim 10, wherein in the step S40), the displacement platform drives the sheet-shaped electrode relative to the workpiece to be processed along the sheet during processing The length or width direction of the electrode is horizontally moved; or the displacement platform drives the sheet electrode to reciprocate relative to the surface to be processed of the workpiece during processing.
The method of preparing a surface-strengthening coating according to claim 10, further comprising the step S50) after the step S40), cleaning the surface to be processed of the processed workpiece.
The method of preparing a surface-strengthening coating according to claim 14, further comprising the step S60) after the step S50), finishing the workpiece.