LU500818B1 - Cluster Micro Heat Pipe Forced Cooling Electric Discharge Machining Device and Machining Method Thereof - Google Patents

Abstract

The disclosure relates to electric discharge machining equipment, and a machining method thereof. The device includes a servo feed mechanism composed of a fixed end and a telescopic end, and includes an L-shaped fixed plate, a fixed frame, a chuck, a first tool electrode module whose the bottom is connected with a second tool electrode module, a drive assembly, a heat pipe cooling assembly, and a cooler. The L-shaped fixed plate is welded on the outer wall of the fixed end which is welded on the outer wall of the telescopic end; the chuck is mounted at the bottom of the fixed frame; the first tool electrode module is inserted into the inner wall of the chuck; the heat pipe cooling assembly is arrayed at the top of the first tool electrode module; and the top end of the heat pipe cooling assembly is arranged in the cooler.

Description

Description Cluster Micro Heat Pipe Forced Cooling Electric Discharge Machining Device and Machining Method Thereof Technical Field

[0001] The disclosure relates to the technical field of electric discharge machining equipment, specifically to a cluster micro heat pipe forced cooling electric discharge machining device and a machining method thereof. Background

[0002] With the continuous development of science and technology, the integration level of semiconductors is getting higher and higher, and functions are becoming more and more complicated. As a result, the density of semiconductor encapsulation is increasing, there are more and more lead wires, and the volume is smaller and smaller, the weight is lighter and lighter, and upgrading is faster and faster. With the development trend of small, thin, short, and light semiconductor products and the continuous updating of semiconductor technologies, semiconductor encapsulation technologies are developing at a high speed toward high density and high performance, which puts forward higher and higher precision requirements for encapsulation molds.

[0003] A semiconductor encapsulation mold needs to have many performance requirements such as good machining characteristics, matrix rigidity, pressure resistance, abrasion resistance, dimensional stability, good mold release, and corrosion resistance. Key parts of the encapsulation mold such as an insert and a mold usually use powder metallurgical steel such as ASP23 and ASP30 which are difficult to machine as materials. The most commonly used machining method is electric discharge machining.

[0004] The patent CN 201210541192.8 discloses a cold-electrode asymmetrical heat dissipation electric discharge machining method. By the adoption of a method for cooling a tool electrode, such as flushing liquid, flushing gas, a heat sink, a heat pipe, and a semiconductor, the heat dissipation of the tool electrode is enhanced, and the purposes of improving interelectrode cooling, chip removal and deionization during electric discharge machining can be achieved; the loss of the tool electrode is further reduced; and the purposes of improving the electric discharge machining stability and improving the machining precision and the surface quality are achieved. An electric discharge machining test of TC4 titanium alloy shows that the lower the temperature of the tool electrode, the higher the material removal rate, the lower the relative loss of the tool electrode, and the less the surface roughness of a workpiece. However, these methods are still low in tool electrode cooling effect, which easily causes the temperature of the tool electrode to continue to rise and exceed an appropriate temperature range during the electric discharge machining, thus affecting the machining stability. If the temperature of the tool electrode exceeds the limit, a temperature controller controls a power supply of an electric discharge machining machine tool to be turned off and machine tool knives to be replaced till the temperature of a tool electrode machining region is reduced to a set temperature, and then controls the machine tool to be turned on for continuous machining, thus achieving a discontinuous machining state and affecting the machining efficiency. The tool electrode cooling method cannot fully exert the machining effect. Summary

[0005] For the problems in the prior art, the disclosure provides a cluster micro heat pipe forced cooling electric discharge machining device.

[0006] The technical solution adopted by the disclosure to solve the technical problems: À cluster micro heat pipe forced cooling electric discharge machining device includes a servo feed mechanism, an L-shaped fixed plate, a fixed frame, a chuck, a first tool electrode module, a second tool electrode module, a drive assembly, a heat pipe cooling assembly, and a cooler. The servo feed mechanism is composed of a fixed end and a telescopic end; the L-shaped fixed plate is welded on the outer wall of the fixed end; the fixed frame is welded on the outer wall of the telescopic end; the chuck is mounted at the bottom of the fixed frame; the first tool electrode module is inserted into the inner wall of the chuck; the bottom of the first tool electrode module is connected with the second tool electrode module; the heat pipe cooling assembly is arrayed at the top of the first tool electrode module; the top end of the heat pipe cooling assembly is arranged in the cooler; the drive assembly is arranged between two heat pipe cooling assemblies in a transverse direction; and a plurality of groups of drive assemblies are fixedly connected with the L-shaped fixed plate through a round rod;

[0007] the first tool electrode module is composed of four rectangular copper blocks fixed by means of bolts; C-shaped semicircular slots are formed in connection surfaces of two adjacent rectangular copper blocks; the tops of the C-shaped semicircular slots communicate with linear semicircular slots; a C-shaped circular channel is formed between two adjacent C-shaped semicircular slots; a linear channel is formed between two adjacent linear semicircular slots; and insertion slots are formed in joints of the upper end surfaces of the rectangular copper blocks and the heat pipe cooling assemblies; and

[0008] the second tool electrode module is composed of two semicircular copper blocks, and the two semicircular copper blocks are welded on the lower end surfaces of the rectangular copper blocks.

[0009] Further, each heat pipe cooling assembly includes a copper heat pipe shell vertically inserted into the insertion slot; a through hole is formed in a center position in the copper heat pipe shell; trenches are formed in the inner wall of the through hole at equal intervals in a circumferential direction; the inner wall of the through hole is axially inserted with a liquid absorption core; one end of the copper heat pipe shell close to the cooler is welded with an upper end cover; and the other end of the copper heat pipe shell is welded with a lower end cover.

[0010] Further, a vacuum environment exists inside the copper heat pipe shell; the liquid absorption core is a copper fiber sintered via a hydrogen furnace; and the liquid absorption core and the inner wall of the through hole are fixed by electroplating.

[0011] Further, the copper fiber is an irregularly distributed member that is machined via a multi-tooth cutter and has a chopped coarse surface.

[0012] Further, a ball channel is symmetrically formed on the outer wall of a blind end of the copper heat pipe shell located on one side of the insertion slot; a first connection channel is transversely formed in the top of the ball channel, and the first connection channel communicates with the linear channel; a second connection channel is formed in the outer wall of the lower end cover, and the second connection channel communicates with the ball channel; a cooling chamber is formed among the C-shaped circular channel, the linear channel, the ball channel,

the first connection channel, and the second connection channel; the cooling chamber is filled with a heat transfer ball; and a gap between the heat transfer ball and the cooling chamber is filled with high-temperature resistant silicone grease.

[0013] Further, each drive assembly includes a drive housing fixed at one end of the round rod by means of spot welding; a mounting slot is formed in the bottom of the drive housing; sliding rods are symmetrically mounted on the inner wall of the mounting slot; the outer walls of the two sliding rods are sleeved with sliding blocks; the outer walls of the sliding rods located at the tops of the sliding blocks are sleeved with first springs; the outer walls of the sliding blocks are welded with limiting disks; the outer walls of the sliding blocks located between the two limiting disks are sleeved with movable blocks; the outer walls of the sliding blocks located on the right sides of the movable blocks are sleeved with second springs; the bottoms of the movable blocks are welded with drive rods; a roll shaft is mounted on one side of each drive rod; a limiting block is mounted on the inner wall of the mounting slot; and the arc surface of the limiting block is fitted to the outer walls of the roll shafts.

[0014] Further, a steel ball is embedded into a center position of the bottom of each drive rod, and the drive rod is located right above a gap between two adjacent heat transfer balls in the linear channel.

[0015] In addition, the disclosure further provides a machining method of a cluster micro heat pipe forced cooling electric discharge machining device. The machining method of the cluster micro heat pipe forced cooling electric discharge machining device specifically includes the following steps:

[0016] S1, carrying out preparation work: a workpiece to be machined is manually placed on a machining table first; the workpiece and the second tool electrode module are respectively connected to two electrodes of a pulse power supply; a machining chamber is filled with working liquid; and the filling is stopped till the level of the working liquid is higher than an upper surface of the workpiece, the working liquid being one of kerosene, plasma water, and emulsified liquid;

[0017] S2, realizing discharge breakdown: the servo feed mechanism is connected with an external power supply and is controlled to drive the telescopic end to descend, so as to drive, under the action of the fixed frame and the chuck, the second tool electrode module to be fed to the workpiece; when a gap between the two electrodes reaches a certain distance, a pulse voltage applied to the two electrodes breaks down the working liquid, thus generating spark discharge and instantly concentrating a large amount of heat energy in a discharged micro channel, which causes a trace amount of metal material on part of the surface of the workpiece in the area to be immediately melted and gasified and explosively splash into the working liquid for quick condensation to form solid metal particles that are brought away by the working liquid; and at the moment, a tiny recess trace is left on the surface of the workpiece;

[0018] S3, performing electrode cooling: in a working process of the second tool electrode module, one end of the bottom of the heat pipe cooling assembly that is in contact with the second tool electrode module is heated so that the liquid in the heat pipe cooling assembly in the area is evaporated; since the heat pipe cooling assembly is in a vacuum state inside, the evaporated gas rises to the top of the heat pipe cooling assembly and is then cooled for condensation under the action of the cooler; and the condensate flows to the bottom along the heat pipe cooling assembly and is then heated and evaporated, cyclically, so as to realize a cooling effect on the second tool electrode module;

[0019] S4, performing temperature transfer: in the working process of the second tool electrode module, the heat transfer balls are arranged in the cooling chamber that has a horizontal height less than the lower end surface of the heat pipe cooling assembly; and the temperature of a lower area of the second tool electrode module is transferred to the surface of the heat pipe cooling assembly by means of a heat conduction piece composed of several of the heat transfer balls; and

[0020] S5, driving the heat transfer balls: when the servo feed mechanism drives the second tool electrode module to rise as a whole, the second tool electrode module is in contact with the drive assembly, and the heat transfer balls arranged in the cooling chamber clockwise move under the pushing of the drive assembly.

[0021] The beneficial effects of the disclosure:

[0022] (1) According to the cluster micro heat pipe forced cooling electric discharge machining device of the disclosure, the tiny micro trenches can be formed relying on the chopped, coarse, specially-shaped structures that are mutually bonded on the surfaces of the copper fibers. Combination of such micro trench structures and the chopped structures on the surfaces of the copper fibers can increase the capillary pressure and enhance the evaporation/condensation process of two ends in a micro heat pipe, thus effectively improving the cooling performance of the heat pipe cooling assembly.

[0023] (2) According to the cluster micro heat pipe forced cooling electric discharge machining device of the disclosure, the C-shaped circular channels and the linear channels are formed in the tool electrodes, and the ball channels, the first connection channels, and the second connection channels are formed in the outer walls of the copper heat pipe shells. When the copper heat pipe shells are inserted into the top ends of the rectangular copper blocks, the cooling chamber is formed among the C-shaped circular channels, the linear channels, the ball channels, the first connection channels, and the second connection channels, and the heat conduction piece is formed by the heat transfer balls arranged in the cooling chamber so that a contact area between the electrodes and the copper heat pipe shells is enlarged; and the temperature below a horizontal position of the electrode is transferred to the surfaces of the copper heat pipe shells so that the temperature of the tool electrode in the electric discharge machining process can be reduced to the maximum extent, which is conducive to improving an interelectrode deionization state and improving the electric discharge machining stability, thus reducing the loss of the tool electrode and shortening the interelectrode medium deionization time. On one hand, unstable discharge such as unstable arc discharge, stable arc discharge, and short circuit can be reduced or avoided, the machining efficiency is improved, and at the same time, the coarseness of a machined surface can be reduced, and the machining precision can be improved. On the other hand, a smaller pulse interval or higher current can be used for machining so that the machining efficiency can be further improved.

[0024] (3) According to the cluster micro heat pipe forced cooling electric discharge machining device of the disclosure, electric discharge machining is mainly for a situation of up-and-down movement along the X-axis. The servo feed mechanism drives the electrode to vertically move up to generate a drive force so that the transfer balls arranged in the cooling chambers clockwise displace under the action of the drive assemblies, which increases the contact rate of the heat conduction piece and the copper heat pipe shell, thus improving the heat transfer efficiency and further improving the electrode cooling efficiency. The phenomenon that a traditional tool electrode cooling measure has a poor cooling effect so that the temperature of the tool electrode in the electric discharge machining process continues to rise and exceeds a suitable temperature range to affect the machining quality can be avoided, and no discontinuous machining state occurs so that the machining effect of the tool electrode cooling method can be fully exerted. Brief Description of Figures

[0025] The disclosure is further described below in combination with the accompanying drawings and embodiments.

[0026] FIG. 1 is a three-dimensional view of an overall structure of the disclosure;

[0027] FIG. 2 is a sectional view of a rectangular copper block and a drive assembly in a direction M-M in FIG. 1;

[0028] FIG. 3 is a schematic overall structural view of a heat pipe cooling assembly of the disclosure;

[0029] FIG. 4 is a partially sectional view of a heat pipe cooling assembly of the disclosure;

[0030] FIG. 5 is a schematic partially enlarged view of an area A in FIG. 2 of the disclosure; and

[0031] FIG. 6 is a flowchart of the disclosure.

[0032] In the drawings: 1: servo feed mechanism; 2: L-shaped fixed plate; 3: fixed frame; 4: chuck; 5: first tool electrode module; 6: second tool electrode module; 7: drive assembly; 8: heat pipe cooling assembly; 9: cooler; 51: rectangular copper block; 52: C-shaped semicircular slot; 53: linear semicircular slot; 54: insertion slot; 61: semicircular copper block; 81: copper heat pipe shell; 82: upper end cover; 83: lower end cover; 84: trench; 85: liquid absorption core; 811: ball channel; 812: first connection channel; 813: second connection channel; 814: heat transfer ball; 815: high-temperature resistant silicone grease; 71: drive housing; 72: sliding rod; 73: first spring; 74: second spring; 75: sliding block; 76: movable block; 77: limiting disk; 78: drive rod; 79: limiting block; 70: roll shaft. Detailed Description

[0033] In order to make the technical means, creative features, objectives and effects of the disclosure easy to understand, the following further describes the disclosure in conjunction with specific implementation modes.

[0034] As shown in FIG. 1 to FIG. 6, a cluster micro heat pipe forced cooling electric discharge machining device of the disclosure includes a servo feed mechanism 1, an L-shaped fixed plate 2, a fixed frame 3, a chuck 4, a first tool electrode module 5, a second tool electrode module 6, a drive assembly 7, a heat pipe cooling assembly 8, and a cooler 9. The servo feed mechanism 1 is composed of a fixed end and a telescopic end; the L-shaped fixed plate 2 is welded on the outer wall of the fixed end; the fixed frame 3 is welded on the outer wall of the telescopic end; the chuck 4 is mounted at the bottom of the fixed frame 3; the first tool electrode module 5 is inserted into the inner wall of the chuck 4; the bottom of the first tool electrode module 5 is connected with the second tool electrode module 6; the heat pipe cooling assembly 8 is arrayed at the top of the first tool electrode module 5; the top end of the heat pipe cooling assembly 8 is arranged in the cooler 9; the drive assembly 7 is arranged between two heat pipe cooling assemblies 8 in a transverse direction; and a plurality of groups of drive assemblies 7 are fixedly connected with the L-shaped fixed plate 2 through a round rod; and

[0035] the first tool electrode module 5 is composed of four rectangular copper blocks 51 fixed by means of bolts; C-shaped semicircular slots 52 are formed in connection surfaces of two adjacent rectangular copper blocks 51; the tops of the C- shaped semicircular slots 52 communicate with linear semicircular slots 53; a C- shaped circular channel is formed between two adjacent C-shaped semicircular slots 52; a linear channel is formed between two adjacent linear semicircular slots 53; insertion slots 54 are formed in joints of the upper end surfaces of the rectangular copper blocks 51 and the heat pipe cooling assemblies 8; and the second tool electrode module 6 is composed of two semicircular copper blocks 61, and the two semicircular copper blocks 61 are welded on the lower end surfaces of the rectangular copper blocks 51. During specific work, the surfaces of the rectangular copper blocks 51 provided with the C-shaped semicircular slots 52 are manually clung to each other, and the rectangular copper blocks 51 on two sides are sequentially fitted to the side walls of the rectangular copper blocks 51 in the middle area; finally, the bolts are inserted from bolt holes on two sides of the rectangular copper blocks 51, and nuts are screwed, so a to quickly complete the assembling of the first tool electrode module 5 and the second tool electrode module 6.

[0036] Each heat pipe cooling assembly 8 includes a copper heat pipe shell 81 vertically inserted into the insertion slot 54; a through hole is formed in a center position in the copper heat pipe shell 81; trenches 84 are formed in the inner wall of the through hole at equal intervals in a circumferential direction; the inner wall of the through hole is axially inserted with a liquid absorption core 85; one end of the copper heat pipe shell 81 close to the cooler 9 is welded with an upper end cover 82; and the other end of the copper heat pipe shell 81 is welded with a lower end cover

83. À vacuum environment exists inside the copper heat pipe shell 81; the liquid absorption core 85 is a copper fiber sintered via a hydrogen furnace; and the liquid absorption core 85 and the inner wall of the through hole are fixed by electroplating. The copper fiber is an irregularly distributed member that is machined via a multi- tooth cutter and has a chopped coarse surface. The heat pipe cooling assembly 8 performs forced cooling on the second tool electrode module 6 at high heat dissipation efficiency. The heat of the second tool electrode module 6 is input to the copper heat pipe shell 81 via an evaporation section at the lower end of the copper heat pipe shell 81 and is output to the cooler 9 via a condensation section at the upper end of the copper heat pipe shell 81. When the lower end of the copper heat pipe shell 81 is heated, the liquid in the liquid absorption core 85 is evaporated and gasified.

Steam flows to the condensation section at the upper end under a pressure difference and releases heat, so as to be condensed into liquid; and the backflow liquid flows back to the evaporation section along the liquid absorption core 85 under the action of a capillary force.

This process is circulated so that the heat is continuously transferred to the condensation section from the evaporation section of the micro heat pipe.

The temperatures of the first tool electrode module 5 and the second tool electrode module 6 are reduced to the maximum extent; the interelectrode deionization state is improved, and the interelectrode medium deionization time is shortened; and unstable discharge such as unstable arc discharge, stable arc discharge, and short circuit can be reduced or avoided.

A ball channel 811 is symmetrically formed on the outer wall of a blind end of the copper heat pipe shell 81 located on one side of the insertion slot 54; a first connection channel 812 is transversely formed in the top of the ball channel 811, and the first connection channel 812 communicates with the linear channel; a second connection channel 813 is formed in the outer wall of the lower end cover 83, and the second connection channel 813 communicates with the ball channel 811; a cooling chamber is formed among the C-shaped circular channel, the linear channel, the ball channel 811, the first connection channel 812, and the second connection channel 813; the cooling chamber is filled with a heat transfer ball 814; and a gap between the heat transfer ball 814 and the cooling chamber is filled with high-temperature resistant silicone grease 815. During specific work, before the first tool electrode module 5 and the second tool electrode module 6 are assembled, the heat transfer balls 814 need to be manually placed in the C-shaped circular channel and the linear channel in sequence, and whether the C-shaped circular channel and the linear channel are filled with the heat transfer balls 814 is visually determined.

After the channels are filled, the heat pipe cooling assembly 8 is manually taken out, and the heat transfer balls 814 are put into the ball channel 811, the first connection channel 812, and the second connection channel 813. After the ball channel 811, the first connection channel 812, and the second connection channel 813 are full of the heat transfer balls 814, the copper heat pipe shell 81 in this area is manually inserted into the insertion slot 54. At this time, the whole cooling chamber is full of the heat transfer balls 814. At this time, several of the heat transfer balls 814 form a heat conduction piece.

When the second tool electrode module 6 works, the temperature of the lower part of the second tool electrode module 6 may be transferred to the copper heat pipe shell 81 through the heat conduction piece formed by the several heat transfer balls 814, which effectively enlarges a contact area between the second tool electrode module 6 and the copper heat pipe shell 81 and further ensures the heat dissipation effect.

[0037] Each drive assembly 7 includes a drive housing 71 fixed at one end of the round rod by means of spot welding; a mounting slot is formed in the bottom of the drive housing 71; sliding rods 72 are symmetrically mounted on the inner wall of the mounting slot; the outer walls of the two sliding rods 72 are sleeved with sliding blocks 75; the outer walls of the sliding rods 72 located at the tops of the sliding blocks 75 are sleeved with first springs 73; the outer walls of the sliding blocks 75 are welded with limiting disks 77; the outer walls of the sliding blocks 75 located between the two limiting disks 77 are sleeved with movable blocks 76; the outer walls of the sliding blocks 75 located on the right sides of the movable blocks 76 are sleeved with second springs 74; the bottoms of the movable blocks 76 are welded with drive rods 78; a roll shaft 70 is mounted on one side of each drive rod 78; a limiting block 79 is mounted on the inner wall of the mounting slot; and the arc surface of the limiting block 79 is fitted to the outer walls of the roll shafts 70. During specific work, when the telescopic end of the servo feed mechanism 1 drives the second tool electrode module 6 to rise as a whole, the drive rod 78 vertically moves down relative to the upper end surface of the rectangular copper block 51, and the drive rod 78 will be inserted into a gap between the heat transfer balls 814 located in the linear channel.

Furthermore, in the descending process, the roll shaft 70 will roll along the arc surface of the limiting block 79. At this time, the arc surface applies a horizontally rightward thrust to the roll shaft 70 so that the movable block 76 slides horizontally to the right along the outer wall of the sliding block 75 under the action of the thrust, and the second spring 74 is compressed by the movable block 76 to generate a resilience force so that the drive rod 78 pulls the heat transfer balls 814 in the cooling chamber to clockwise move.

That is, the heat conduction piece consisting of the heat transfer balls 814 can move relatively in the cooling chamber so that the heat conduction piece can quickly transfer the temperature of the lower position of the first tool electrode module 5 to the copper heat pipe shell 81, which further ensures the heat dissipation effect of the heat pipe cooling assembly 8. In the process that the heat transfer balls 814 clockwise move, the high-temperature resistant silicone grease 815 is attached to the surfaces of the heat transfer balls 814 and moves together with them.

In this way, when the heat transfer balls 814 roll into the ball channel 811, the first connection channel 812, and the second connection channel 813, a contact area between the heat transfer balls 814 and the outer wall of the copper heat pipe shell 81 is effectively enlarged, and the heat conduction efficiency is higher.

When the lower end of the drive rod 78 contacts the bottom of the linear channel, the sliding block 75 vertically moves up along the sliding rod 72, and the first spring 73 is compressed by the sliding block 75 and generates a resilience force.

That is, when the servo feed mechanism 1 drives the first tool electrode module 5 and the second tool electrode module 6 to work again, the resilience forces generated by the compression of the second spring 74 and the first spring 73 can counteract with the movable block 76 and the sliding block 75 and enable them to return to the original positions.

[0038] A steel ball is embedded into a center position of the bottom of each drive rod 78. When the bottom of the drive rod 78 contacts the linear channel, the steel ball at the bottom of the drive rod 78 will move horizontally to the right along the linear channel, so as to prevent a corner angle of the bottom of the drive rod 78 from directly acting on the inner wall of the linear channel and damaging the linear channel. The drive rod 78 is located right above a gap between two adjacent heat transfer balls 814 in the linear channel.

[0039] In addition, the disclosure further provides a machining method of a cluster micro heat pipe forced cooling electric discharge machining device. The machining method of the cluster micro heat pipe forced cooling electric discharge machining device specifically includes the following steps:

[0040] S1, preparation work is carried out: a workpiece to be machined is manually placed on a machining table first; the workpiece and the second tool electrode module 6 are respectively connected to two electrodes of a pulse power supply; a machining chamber is filled with working liquid; and the filling is stopped till the level of the working liquid is higher than an upper surface of the workpiece, the working liquid being one of kerosene, plasma water, and emulsified liquid;

[0041] S2, discharge breakdown is realized: the servo feed mechanism 1 is connected with an external power supply and is controlled to drive the telescopic end to descend, so as to drive, under the action of the fixed frame 3 and the chuck 4, the second tool electrode module 6 to be fed to the workpiece; when a gap between the two electrodes reaches a certain distance, a pulse voltage applied to the two electrodes breaks down the working liquid, thus generating spark discharge and instantly concentrating a large amount of heat energy in a discharged micro channel, which causes a trace amount of metal material on part of the surface of the workpiece in the area to be immediately melted and gasified and explosively splash into the working liquid for quick condensation to form solid metal particles that are brought away by the working liquid; and at the moment, a tiny recess trace is left on the surface of the workpiece;

[0042] S3, electrode cooling is performed: in a working process of the second tool electrode module 6, one end of the bottom of the heat pipe cooling assembly 8 that is in contact with the second tool electrode module 6 is heated so that the liquid in the heat pipe cooling assembly 8 in the area is evaporated; since the heat pipe cooling assembly 8 is in a vacuum state inside, the evaporated gas rises to the top of the heat pipe cooling assembly 8 and is then cooled for condensation under the action of the cooler 9; and the condensate flows to the bottom along the heat pipe cooling assembly 8 and is then heated and evaporated, cyclically, so as to realize a cooling effect on the second tool electrode module 6;

[0043] S4, temperature transfer is performed: in the working process of the second tool electrode module 6, the heat transfer balls 814 are arranged in the cooling chamber that has a horizontal height less than the lower end surface of the heat pipe cooling assembly 8; and the temperature of a lower area of the second tool electrode module 6 is transferred to the surface of the heat pipe cooling assembly 8 by means of a heat conduction piece composed of several of the heat transfer balls 814; and

[0044] S5, the heat transfer balls are driven: when the servo feed mechanism 1 drives the second tool electrode module 6 to rise as a whole, the second tool electrode module 6 is in contact with the drive assembly 7, and the heat transfer balls 814 arranged in the cooling chamber clockwise move under the pushing of the drive assembly 7.The above shows and describes the basic principles, main features and advantages of the disclosure.

Those skilled in the art should understand that the disclosure is not limited by the foregoing embodiments.

The descriptions in the foregoing implementation modes and in the specification only illustrate the principles of the disclosure.

The disclosure may have various changes and improvements without departing from the spirit and scope of the disclosure, and these changes and improvements all fall within the scope claimed by the disclosure.

The scope claimed by the disclosure is defined by the appended claims and their equivalents.

Claims (8)

Claims:

1. A cluster micro heat pipe forced cooling electric discharge machining device, comprising a servo feed mechanism (1), an L-shaped fixed plate (2), a fixed frame (3), a chuck (4), a first tool electrode module (5), a second tool electrode module (6), a drive assembly (7), a heat pipe cooling assembly (8), and a cooler (9), wherein the servo feed mechanism (1) is composed of a fixed end and a telescopic end; the L- shaped fixed plate (2) is welded on the outer wall of the fixed end; the fixed frame (3) is welded on the outer wall of the telescopic end; the chuck (4) is mounted at the bottom of the fixed frame (3); the first tool electrode module (5) is inserted into the inner wall of the chuck (4); the bottom of the first tool electrode module (5) is connected with the second tool electrode module (6); the heat pipe cooling assembly (8) is arrayed at the top of the first tool electrode module (5); the top end of the heat pipe cooling assembly (8) is arranged in the cooler (9); the drive assembly (7) is arranged between two heat pipe cooling assemblies (8) in a transverse direction; and a plurality of groups of drive assemblies (7) are fixedly connected with the L-shaped fixed plate (2) through a round rod; the first tool electrode module (5) is composed of four rectangular copper blocks (51) fixed by means of bolts; C-shaped semicircular slots (52) are formed in connection surfaces of two adjacent rectangular copper blocks (51); the tops of the C-shaped semicircular slots (52) communicate with linear semicircular slots (53); a C-shaped circular channel is formed between two adjacent C-shaped semicircular slots (52); a linear channel is formed between two adjacent linear semicircular slots (53); and insertion slots (54) are formed in joints of the upper end surfaces of the rectangular copper blocks (51) and the heat pipe cooling assemblies (8); and the second tool electrode module (6) is composed of two semicircular copper blocks (61), and the two semicircular copper blocks (61) are welded on the lower end surfaces of the rectangular copper blocks (51).

2. The cluster micro heat pipe forced cooling electric discharge machining device according to claim 1, wherein each heat pipe cooling assembly (8) comprises a copper heat pipe shell (81) vertically inserted into the insertion slot (54); a through hole is formed in a center position in the copper heat pipe shell (81); trenches (84) are formed in the inner wall of the through hole at equal intervals in a circumferential direction; the inner wall of the through hole is axially inserted with a liquid absorption core (85); one end of the copper heat pipe shell (81) close to the cooler (9) is welded with an upper end cover (82); and the other end of the copper heat pipe shell (81) is welded with a lower end cover (83).

3. The cluster micro heat pipe forced cooling electric discharge machining device according to claim 2, wherein a vacuum environment exists inside the copper heat pipe shell (81); the liquid absorption core (85) is a copper fiber sintered via a hydrogen furnace; and the liquid absorption core (85) and the inner wall of the through hole are fixed by electroplating.

4, The cluster micro heat pipe forced cooling electric discharge machining device according to claim 3, wherein the copper fiber is an irregularly distributed member that is machined via a multi-tooth cutter and has a chopped coarse surface.

5. The cluster micro heat pipe forced cooling electric discharge machining device according to claim 2, wherein a ball channel (811) is symmetrically formed on the outer wall of a blind end of the copper heat pipe shell (81) located on one side of the insertion slot (54); a first connection channel (812) is transversely formed in the top of the ball channel (811), and the first connection channel (812) communicates with the linear channel; a second connection channel (813) is formed in the outer wall of the lower end cover (83), and the second connection channel (813) communicates with the ball channel (811); a cooling chamber is formed among the C-shaped circular channel, the linear channel, the ball channel (811), the first connection channel (812), and the second connection channel (813); the cooling chamber is filled with a heat transfer ball (814); and a gap between the heat transfer ball (814) and the cooling chamber is filled with high-temperature resistant silicone grease (815).

6. The cluster micro heat pipe forced cooling electric discharge machining device according to claim 1, wherein each drive assembly (7) comprises a drive housing (71) fixed at one end of the round rod by means of spot welding; a mounting slot is formed in the bottom of the drive housing (71); sliding rods (72) are symmetrically mounted on the inner wall of the mounting slot; the outer walls of the two sliding rods (72) are sleeved with sliding blocks (75); the outer walls of the sliding rods (72) located at the tops of the sliding blocks (75) are sleeved with first springs (73); the outer walls of the sliding blocks (75) are welded with limiting disks (77); the outer walls of the sliding blocks (75) located between the two limiting disks (77) are sleeved with movable blocks (76); the outer walls of the sliding blocks (75) located on the right sides of the movable blocks (76) are sleeved with second springs (74); the bottoms of the movable blocks (76) are welded with drive rods (78); a roll shaft (70) is mounted on one side of each drive rod (78); a limiting block (79) is mounted on the inner wall of the mounting slot; and the arc surface of the limiting block (79) is fitted to the outer walls of the roll shafts (70).

7. The cluster micro heat pipe forced cooling electric discharge machining device according to claim 1, wherein a steel ball is embedded into a center position of the bottom of each drive rod (78); and the drive rod (78) is located right above a gap between two adjacent heat transfer balls (814) in the linear channel.

8. The cluster micro heat pipe forced cooling electric discharge machining device according to any one of claims 1-7, wherein the cluster micro heat pipe forced cooling electric discharge machining device comprises a machining method of a cluster micro heat pipe forced cooling electric discharge machining device, and the method specifically comprises the following steps: s1, carrying out preparation work: a workpiece to be machined is manually placed on a machining table first; the workpiece and the second tool electrode module (6) are respectively connected to two electrodes of a pulse power supply; a machining chamber is filled with working liquid; and the filling is stopped till the level of the working liquid is higher than an upper surface of the workpiece, the working liquid being one of kerosene, plasma water, and emulsified liquid; s2, realizing discharge breakdown: the servo feed mechanism (1) is connected with an external power supply and is controlled to drive the telescopic end to descend, so as to drive, under the action of the fixed frame (3) and the chuck (4), the second tool electrode module (6) to be fed to the workpiece; when a gap between the two electrodes reaches a certain distance, a pulse voltage applied to the two electrodes breaks down the working liquid, thus generating spark discharge and instantly concentrating a large amount of heat energy in a discharged micro channel, which causes a trace amount of metal material on part of the surface of the workpiece in the area to be immediately melted and gasified and explosively splash into the working liquid for quick condensation to form solid metal particles that are brought away by the working liquid; and at the moment, a tiny recess trace is left on the surface of the workpiece;

s3, performing electrode cooling: in a working process of the second tool electrode module (6), one end of the bottom of the heat pipe cooling assembly (8) that is in contact with the second tool electrode module (6) is heated so that the liquid in the heat pipe cooling assembly (8) in the area is evaporated; since the heat pipe cooling assembly (8) is in a vacuum state inside, the evaporated gas rises to the top of the heat pipe cooling assembly (8) and is then cooled for condensation under the action of the cooler (9); and the condensate flows to the bottom along the heat pipe cooling assembly (8) and is then heated and evaporated, cyclically, so as to realize a cooling effect on the second tool electrode module (6);

s4, performing temperature transfer: in the working process of the second tool electrode module (6), the heat transfer balls (814) are arranged in the cooling chamber that has a horizontal height less than the lower end surface of the heat pipe cooling assembly (8); and the temperature of a lower area of the second tool electrode module (6) is transferred to the surface of the heat pipe cooling assembly

(8) by means of a heat conduction piece composed of several of the heat transfer balls (814); and s5, driving the heat transfer balls: when the servo feed mechanism (1) drives the second tool electrode module (6) to rise as a whole, the second tool electrode module (6) is in contact with the drive assembly (7), and the heat transfer balls (814)

arranged in the cooling chamber clockwise move under the pushing of the drive assembly (7).