CN102773572B - Laminated electrode formed by internal flushing liquid for high-speed electrical discharge machining - Google Patents

Abstract

The invention discloses an overlaid plate type internal solution filling forming electrode for high-speed electric discharge machining, which comprises an electrode overlaid plate set and an electrode contact, wherein the electrode overlaid plate set is formed by overlaying and fastening a plurality of electrode plates, so forming electrodes are formed for electric discharge machining, a plurality of through grooves are formed in the surfaces of the electrode plates, a plurality of through holes are formed between the forming electrodes through overlaying the electrode plates, and are used for being filled with the working solution for realizing the forcible internal solution filling during the machining process, the electrode contact comprises an electrode overlaid plate port, a working solution inlet and a machine tool fixture port, and the forming electrodes are connected with a machine tool spindle chuck through the electrode contact, and provide the channels for the working solution to flow towards the through holes in the electrode overlaid plate set during the internal solution filling.

Description

Laminated electrode formed by internal flushing liquid for high-speed electrical discharge machining

technical field

The invention relates to a forming electrode belonging to the technical field of special processing, in particular, a laminated internal flushing forming electrode for high-speed electric discharge machining. the

Background technique

High-speed electrical discharge machining is a new type of electrical machining method that uses short arc discharge that can conduct a discharge current of up to tens of thousands of amperes to efficiently remove workpiece materials, especially difficult-to-cut materials. In high-speed electrical discharge machining, electric arc is not only the main method to remove workpiece material, but also may become a potential factor that causes workpiece overheating and burns. In the process of processing, effective measures must be taken to prevent the formation of a stable arc, so that the arc is in a disturbed state and cut off the arc in time when necessary to achieve the so-called "interruption of the arc". Therefore, the key to using short arc for high-speed EDM is to have a reliable arc disturbance and arc breaking mechanism. The arc used in the discharge machining process is a flexible conductor in a dynamic equilibrium state. It is a plasma composed of positive ions, electrons, and neutral particles (atoms or molecules) in roughly equal numbers. It is susceptible to external influences and becomes unstable. or even disappear. The property of the arc makes it possible to increase the distance between the cathode discharge point and the anode discharge point or apply enough external force to the discharge channel to force its deflection and elongation to make it unmaintainable and achieve arc disturbance and arc interruption. The arc breaking method realized by the relative mechanical movement of the electrode relative to the surface of the workpiece can be called mechanical movement arc breaking; while the arc disturbance and arc breaking realized by the fluid power generated by the high-speed flowing working fluid between the electrodes, we call it It is called "hydrodynamic disturbance/interruption". the

After searching the prior art, it is found that the arc breaking in current short arc discharge machining is realized by mechanical movement arc breaking mechanism. For example, Weifang Fangzi Woodworking Machinery Factory disclosed their respective anode mechanical cutting devices and partial structures in patent CN87212711, and Suzhou Electric Machine Tool Research Institute Co., Ltd. disclosed their respective anode mechanical cutting devices and partial structures in patent CN201644967. Anode mechanical cutting originated in the 1940s. It is a method of cutting metal materials using the combined action of electrochemical, electrothermal and mechanical forces. In this method, the workpiece to be cut is used as an anode, which is connected to the positive pole of the DC power supply. When cutting, water glass (sodium silicate) electrolyte is supplied to the incision. The cutting tool rotates at high speed tangentially to the workpiece. Under the action of DC power supply, the metal on the cut surface of the workpiece forms an oxide film due to electrolysis, which is continuously scraped off by the high-speed rotating cutting tool and taken away by the electrolyte. Some convex points on the surface of the incision and the tool are also accompanied by arc discharge, the metal is eroded by high temperature melting and gasification, and is also taken away with the electrolyte, and the cutting tool gradually cuts into the workpiece until it is cut off. There are generally two types of anode mechanical cutting machine tools: disc type and belt type. In addition to the electrolytic effect, the elimination of the discharge arc is also accomplished by the relative movement between the tool and the workpiece. Ye Liangcai disclosed the processing method and equipment combining short arc discharge and mechanical grinding in patent CN87106421A, and further disclosed short arc electric processing equipment in patent CN 1061175A. Melting explosion processing" is a combined processing method that uses a combination of disc-shaped solid tool electrode rotation and short arc discharge to achieve metal melting and removal. During the machining process, the relative movement between the tool and the workpiece is realized through the rotation of the disc-shaped solid tool electrode, so as to break the discharge arc mechanically and realize high-efficiency discharge machining. Determined by its principle, this method is mainly suitable for the processing of rotary parts such as rolls and grinding rolls. In addition, the distributed arc electric erosion machining method disclosed by General Electric Company in patent CN 1693024A, and Suzhou Zhongte Electromechanical Technology Co., Ltd. disclosed in patent CN1397399A the method of high-efficiency milling electric discharge machining using simple hollow long electrodes, both involve A combined machining method combining multi-axis movement of a solid electrode with a single hole and short arc discharge. What they have in common are all based on the relative movement between the electrode and the workpiece to perform the mechanical movement of the discharge arc to break the arc to achieve processing. When this method is used, the forming process of the workpiece is similar to EDM, and a simple electrode is used to etch the workpiece material layer by layer to obtain a three-dimensional shape. This method can be used to process open curved surfaces. Since the simple electrode used in this method has a large loss during the machining process, timely compensation is required. Suzhou Electric Machine Tool Research Institute Co., Ltd. discloses an electrode loss compensation method in patent CN101982280A. the

The tool electrodes used in the above-mentioned disclosed short arc machining methods are traditional non-porous or single-hole electrodes, which do not belong to the "shaping electrode" with a three-dimensional shape, and cannot adopt the single-axis feeding "sinking" processing method Obtain a workpiece with a three-dimensional shape; secondly, the method of mechanical arc breaking is achieved by rotating the workpiece or the electrode. The main relative motion (forming motion) between the tool and the workpiece is tangent to the forming surface of the workpiece, so The arc breaking effect of mechanical motion can be produced, and the high-speed electric discharge machining method based on "hydrodynamic arc disturbance/arc breaking", the relative main motion (forming motion) between the tool and the workpiece is perpendicular to the forming surface of the workpiece, completely relying on high speed The fluid power generated by the flowing working fluid will disturb or even blow off the arc. the

The inventor discloses a cluster electrode in patent CN 1657208A, which discretizes the monolithic formed electrode into one that can be aggregated by a large number of tubular unit electrodes, and can realize the strengthening of porous internal flushing. Different from the above-mentioned traditional liquid flushing method, this porous internal flushing method can significantly increase the flow rate of the working fluid flowing into the electrode space, so that a high-speed working liquid flow with hydrodynamic arc disturbance/interruption capability can be obtained between the electrodes field. However, this cluster electrode still has the following disadvantages: 1) Since its three-dimensional end surface is an approximate curved surface composed of a large number of micro-unit sections, there is a certain error between it and the corresponding target three-dimensional continuous surface in theory. Therefore, when cluster electrodes are used for EDM rough machining, a machining allowance greater than this theoretical error value must be reserved for the subsequent finishing process, which will increase the subsequent processing time and cost of the part. 2) This cluster electrode is composed of a large number of linear unit electrodes, and the axis of the flushing hole is a straight line. It is impossible to obtain a flushing hole with a curved axis or a variable cross-section to further optimize the flushing effect. 3) The clamping method makes the cluster electrode suitable for processing open cavities, but it is difficult to process workpieces with semi-closed cavities. The applicant disclosed a cluster electrode high-speed discharge machining method in patent CN102091839. This method uses cluster electrodes to realize high-pressure, high-flow porous internal flushing, and uses a hydrodynamic arc disturbance/interruption mechanism to ensure short-arc discharge machining. The electrode disclosed in this application can be used as the implementation electrode of the cluster electrode high-speed discharge machining method disclosed in the patent CN102091839 to realize high-speed discharge machining. the

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a laminated internal flushing liquid forming electrode for high-speed electric discharge machining. This forming electrode can not only realize the porous internal flushing function, but also has the ability to perform high-speed electric discharge machining; It has the advantage that the end surface of the electrode is a continuous curved surface, which can avoid the shortage of poor end surface accuracy inherent in the discrete structure of the cluster electrode; in addition, the axis of the flushing hole can be a curve, and the cross section of the flushing hole can be a variable cross section to realize Complicated flushing effect; porous shaped electrodes can be prepared for semi-closed space processing and flushing holes can be opened on the bottom and side of the electrode to achieve high-efficiency flushing. the

The present invention is realized through the following technical solutions, including two parts: an electrode lamination group and a joint. Among them, the electrode laminate group is formed by stacking and fastening a plurality of electrode sheets, and is used to form a shaped electrode for electrical discharge machining. The fastening of the electrode stacks is accomplished by fastening bolts, fastening rivets or tightening nuts. The joint includes an electrode lamination interface, a working fluid inlet and a machine tool fixture interface, which are used to connect the lamination electrode to the spindle chuck of the machine tool through the joint, and provide a channel for the working fluid to lead to the hole system in the lamination electrode group during internal flushing. When the general-purpose electrode stack is used to prepare the stacked electrode, the flushing hole on the periphery that does not participate in the EDM part can be closed with the electrode stack outer frame, elastic sealing ring, and rigid retaining ring to prevent a large amount of working fluid from flowing out, and a tightening nut is used Fix the elastic sealing ring and the rigid retaining ring with the laminated electrode group. When using custom-made electrode stacks to prepare stacked electrodes, it is not necessary to use electrode stack frames, elastic sealing rings, rigid retaining rings and tightening nuts. the

The electrode sheet is made of conductive material. the

The surface of the electrode sheet is provided with a plurality of through grooves. After the electrode sheets are stacked, these through grooves form a plurality of channels between the electrodes for the working fluid to enter during the processing to realize the forced internal flushing during the processing. the

The axis of the through groove can be a straight line or a curve. The axis starts from the interface end and ends at the processing end. the

The cross-sectional shape of the through groove is one of the following: polygonal, arc and elliptical arc. For flushing needs, the cross-sectional shape and size of the channel along the axial direction can be changed. the

In the electrode sheet, except for the interface end of the electrode stack, the final contour of the other surfaces refers to the same profile as the local model obtained after the target solid model is discretized layer by layer. The formation of the final profile can be processed separately before the electrode sheets are stacked or processed as a whole after stacking. the

The electrode sheet has a mounting hole between the upper and lower surfaces for fastening bolts or fastening rivets to pass through. the

The laminated electrode refers to an assembly formed after a certain number of electrode sheets are sequentially superimposed along the thickness direction in the order of layer-by-layer discretization of the target solid model and fixed, and has the same outline as the target solid model. the

The fixed assembly refers to a laminated electrode body formed by fixing a plurality of electrodes with fastening bolts or fastening rivets. There is a spacer or a metal plate between the fastening bolts or fastening rivets and the electrode sheet to prevent the electrode sheet from being damaged by direct force. the

The outer frame of the electrode lamination is a hollow ring structure, its inner contour matches the outer contour of the porous lamination electrode, its lower part has an external thread for connecting with a tightening nut, and the lower part has an opening for tightening. the

The elastic sealing ring is a hollow ring structure, its inner contour matches the machining contour of the porous laminated electrode head, and its outer contour is circular, so as to realize the porous end face sealing of the non-processing area. the

The rigid retaining ring is a hollow ring structure, its inner contour matches the processing contour of the porous lamination electrode head, and its outer contour is a circular boss structure, which is in contact with the tightening nut to achieve elastic sealing ring extrusion. the

The inner opening end of the tightening nut is provided with a blocking surface to realize the axial limit of the rigid stop ring, and an internal thread structure matching the outer frame of the electrode stack is provided on the opposite side of the opening end to connect the electrodes head. the

The upper or middle part of the electrode joint is provided with a hollow flushing hole for the entry of working fluid, and the lower part is provided with a working fluid outlet to realize forced internal flushing during processing. the

The upper part of the electrode joint is provided with a connection interface matching with the spindle of the machine tool. the

The lower part of the electrode joint is provided with an opening for connecting and clamping and fixing the laminated electrode group. The connection and clamping methods are threaded connection, clamp fastening or flange connection. the

The beneficial effects of the present invention are: the laminated electrode has a continuous end surface and can have higher machining accuracy than the cluster electrode, and its porous structure can be enhanced with high-pressure, large-flow internal flushing, and can be disturbed/interrupted by the hydrodynamic arc mechanism Realize short arc high-speed discharge machining; by selecting the size, shape, number and distribution of the flushing holes, the strong flushing process with different flushing effects can be flexibly realized, so as to meet the requirements of hydrodynamic arc disturbance/arc with different flushing effects Arc breaking ability; in addition, the axis of the flushing hole can be a curve to obtain a shaped electrode for side processing or semi-enclosed space processing; the enhanced internal flushing realized by laminated electrodes has hydrodynamic arc disturbance/arc interruption In addition to its ability, it also provides the following three indispensable effects to realize its high-speed electric discharge machining function: First, high-efficiency removal: because the high-speed fluid can melt the liquid and The gaseous metal is blown away from the surface of the workpiece, avoiding the re-solidification of a large amount of molten metal, thereby improving the material removal rate; second, efficient chip removal: because the high-speed fluid can take away the metal debris generated by the high-speed discharge, avoiding the large amount of metal debris Chips stay in the machining gap and cause frequent short circuits to ensure continuous and stable processing; Third, efficient heat dissipation: a large amount of heat generated by short arc discharge can be taken away by the high-speed flowing working fluid through enhanced convection heat transfer, avoiding the temperature of the workpiece being processed Changes in the metallographic structure of the machined surface caused by annealing, as well as the decrease in dimensional accuracy caused by thermal expansion and deformation. The idea, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. the

Description of drawings

Fig. 1a is a schematic assembly diagram of a preferred embodiment of the high-speed electric discharge machining laminated electrode formed with internal flushing liquid according to the present invention. the

Fig. 1b is a schematic perspective view of a preferred embodiment of the high-speed electric discharge machining laminated electrode formed by internal flushing liquid according to the present invention. the

Fig. 2a is a schematic diagram of a part of another embodiment of the high-speed electrical discharge machining electrode formed by internal flushing liquid in another embodiment. the

Fig. 2b is a schematic assembly diagram of an embodiment of a laminated inner-flush formed electrode for high-speed electrical discharge machining according to the present invention. the

Figure 2c is a schematic perspective view of a porous laminated electrode with the axis of the flushing hole as a curve

Detailed ways

Example 1:

As shown in Figure 1a and Figure 1b, this embodiment includes: electrode joint 1, electrode stack 2, pressure plate 3, fastening bolt 4, elastic sealing ring 5, rigid stop ring 6 and tightening nut 7, wherein: fastening Bolt 4 fastens and connects the multi-layer stacked electrode sheet 2, and there is a pressure plate 3 between the fastening bolt 4 and the multi-layer stacked electrode sheet 2. The processing end of the electrode stack 2 is sequentially connected in series with the elastic sealing ring 5 and the rigid retaining ring 6 And tighten the nut 7. The tightening nut 7 realizes the compression of the top contact of the elastic sealing ring 5 and the rigid stop ring 6 and the electrode stack by screwing the external thread on the lower part of the electrode stack 2, and the other end of the electrode stack 2 is connected to the electrode stack. Connector 1 threaded connection. the

The electrode stack 2 is composed of two different sizes of electrode sheets, one of which is 100 mm long, 60 mm wide, and 2.6 mm thick with side slots, and 10 and 11 evenly distributed electrodes with a diameter of 2 mm are respectively arranged on both sides. Semicircular through groove; another side slotted electrode sheet is 100mm long, 60mm wide, and 11.8mm thick, with 10 evenly distributed semicircular through grooves with a diameter of 2mm on one side; through 2 unilaterally grooved electrode sheets and 14 The slotted electrode sheets on both sides of the block are superimposed in a certain order along the thickness direction to form a porous laminated electrode head, and a 40mm hemispherical surface is processed on the end surface, and a 6mm diameter hole along the thickness direction of the electrode stack is provided on the upper side of the middle section. The hole is used to fasten the bolt 3 to fix the electrode head of the porous lamination, and 15mm long M50 external threads are respectively processed at the upper and lower 7.5mm from the axis of the bolt hole to connect the tightening nut and the electrode joint. The square structure is used for tightening the porous lamination electrode head with a wrench. the

The elastic sealing ring 5 is a hollow ring structure, and its inner and outer diameters are 40mm and 55mm, so as to realize the end face sealing of the pores in the non-processing area. the

The rigid stop ring 6 is a hollow ring structure, its inner contour diameter is 40mm, its outer contour is a circular boss structure, the diameter of the big circle of the boss is 55mm, and the height is 2mm, and the diameter of the small circle is 50mm, and the height is 3mm. In contact with the tightening nut to realize the extrusion of the elastic sealing ring. the

The inner diameter of the tightening nut 7 is 55 mm, and a blocking surface with an inner diameter of 50 mm is provided at its opening end to realize the axial limit of the rigid stop ring, and an M55 inner diameter is provided on the opposite side of the opening end. The screw thread structure is used to connect the porous lamination electrode head, and the tightening nut has an outer hexagonal structure with a side length of 34mm, so as to facilitate the tightening of the tightening nut by a wrench. the

The inner side of the electrode joint 1 is provided with a hollow flushing hole with a diameter of 14mm to press into the working fluid to realize reliable forced internal flushing during processing. The outer end of the electrode joint 1 is provided with an M50 thread structure to connect the electrode stack. Sheet 2, the middle section of the electrode joint 1 is an external hexagonal structure with a side length of 34mm, which is convenient for the wrench to tighten the electrode joint. the

Example 2:

As shown in Figure 2a, Figure 2b, and Figure 2c, this embodiment includes: electrode joint 1, electrode stack 2, pressure plate 3, fastening bolt 4 or fastening rivet 4, wherein: fastening bolt 4 or fastening rivet 4 The multi-layer stacked electrode stacks 2 are fastened, and the non-processed ends of the electrode stacks 2 are screwed to the electrode joint 1 . the

The electrode stack 2 is composed of two electrode sheets of different sizes, one of which is 120mm long, 65mm wide, and 3.464mm thick, and one side is provided with 6 evenly distributed semicircular holes with a diameter of 2mm and a curved axis. The other side of the slot is provided with 5 uniformly distributed semicircular slots with a diameter of 2mm and the axis is a curve; the other electrode sheet is 120mm long, 65mm wide, and 16.144mm thick, and one side is provided with 6 axes with a diameter of 2mm. It is a curved semicircular through groove; two electrode sheets with one-side slots and eight electrode sheets with two-side slots are superimposed in a certain order along the thickness direction to form a porous laminated electrode head, and the target profile is processed on its end surface. The upper end is provided with an M55 internal thread for connecting the electrode joint 1, and the upper side of the middle section is provided with a through hole with a diameter of 6 mm along the thickness direction of the electrode sheet for fastening the bolt 4 to fix the porous laminated electrode head. The through hole 8 with a diameter of 2mm along the thickness direction of the electrode sheet is used to fasten the rivets to fix the electrode sheet to prevent the electrode sheet from being too long, and the lower end of the electrode sheet will leak due to the decrease of the sealing performance due to the flushing effect. the

The inner side of the electrode connector 1 is provided with a hollow hole with a diameter of 14 mm to press into the working fluid to realize the forced internal flushing during the processing. The outer end of the electrode connector 1 is provided with an M55 thread structure to connect the laminated electrode. The electrode connector The middle section of the electrode is an external hexagonal structure with a side length of 34mm, which is convenient for the wrench to tighten the electrode joint. The other end of the electrode joint 1 is provided with a columnar interface with an outer diameter of 20mm that matches the machine tool spindle. the

While there has been described what is considered to be the preferred and exemplary embodiment of the invention, other variations of the invention will be readily apparent to those skilled in the art from the teachings herein. It is therefore desirable to ensure that all such variations in the appended technical proposals fall within the true spirit and scope of the invention. the

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims. the

Claims (9)

1. the stacked interior liquid shaped electrode that rushes for high rate discharge processing, comprise electrode stack of laminations and electrode contact, it is characterized in that, described electrode stack of laminations is by a plurality of electrode slice stacks fastening forming, to form the processing of discharging of described shaped electrode, described electrode slice surface is provided with a plurality of grooves, thereby described electrode slice constructs a plurality of through holes between described shaped electrode by superposeing, described through hole is for being pressed into working solution to realize the interior liquid that rushes of forcing of process, described electrode contact comprises electrode lamination interface, working solution entrance and jig interface, described shaped electrode is connected with machine tool chief axis chuck by described electrode contact, and provide interior while rushing liquid working solution lead to the passage of each through hole described in described laminar electrodes group.

2. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 1, it is characterized in that, the center line of the described groove on described electrode slice surface is straight line or curve, the described center line of described groove is from the interface end being connected with described electrode contact, and the processing end of extremely workpiece being processed finishes.

3. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 1, it is characterized in that, described groove along the described electrode slice of axis direction can need have different section shape and sizes according to interior difference of rushing liquid, and the cross sectional shape of the described groove of wherein said electrode slice is selected from a kind of in following shape: polygon, circular arc and elliptic arc.

4. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 1, it is characterized in that, between the upper and lower surface of described electrode slice, have installing hole, the position of the described installing hole of adjacent described electrode slice and measure-alike, the described installing hole of a plurality of so described electrode slices that are stacked connects for through bolt or rivet, thereby combines described electrode slice is fastening.

5. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 1, it is characterized in that, the final outline of described electrode slice is the successively profile of each layer after discretization of target shaped electrode, after a plurality of described electrode slices superpose in order, forms surface for described target shaped electrode profile.

6. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 1, it is characterized in that, also comprise elastic sealing ring, described elastic sealing ring is hollow annular structure, the head machining profile of its inner side profile and described shaped electrode matches, its lateral profile is circular, to realize the end face seal to the described through hole of non-machining area.

7. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 6, it is characterized in that, also comprise rigidity baffle ring and tighten up nut, described rigidity baffle ring is hollow annular structure, the head machining profile of its inner side profile and described shaped electrode matches, its lateral profile is round boss structure, contacts, for realizing the extruding to described elastic sealing ring with the described nut that tightens up.

8. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 7, it is characterized in that, the described inner side openend that tightens up nut is provided with blocking surface to realize the axial limiting to described rigidity baffle ring, in the relative side of described openend, be provided with the female thread structure that matches with the head of described shaped electrode to be connected the head of described shaped electrode, described in tighten up nut outside be hexgonal structure so that spanner tightens up screwing of nut to described.

9. the stacked interior liquid shaped electrode that rushes for high rate discharge processing as claimed in claim 1, it is characterized in that, the inner side of described electrode contact is provided with hollow hole and enters for working solution, realize the interior liquid that rushes that forces in process, the outer upper end of described electrode contact is provided with the connecting interface matching with described machine tool chief axis.

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