CN110369600B - Current loading method for pulse current auxiliary fine blanking processing - Google Patents
Current loading method for pulse current auxiliary fine blanking processing Download PDFInfo
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- CN110369600B CN110369600B CN201910757804.9A CN201910757804A CN110369600B CN 110369600 B CN110369600 B CN 110369600B CN 201910757804 A CN201910757804 A CN 201910757804A CN 110369600 B CN110369600 B CN 110369600B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C51/00—Measuring, gauging, indicating, counting, or marking devices specially adapted for use in the production or manipulation of material in accordance with subclasses B21B - B21F
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D28/00—Shaping by press-cutting; Perforating
- B21D28/02—Punching blanks or articles with or without obtaining scrap; Notching
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D28/00—Shaping by press-cutting; Perforating
- B21D28/02—Punching blanks or articles with or without obtaining scrap; Notching
- B21D28/14—Dies
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D37/00—Tools as parts of machines covered by this subclass
- B21D37/16—Heating or cooling
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Abstract
The current of the invention acts on metal and has electric heating effect and electro-plasticity, wherein the high-frequency pulse current has the capability of healing the plastic strain damage of the metal. The invention introduces the electro-plasticity and the electric heating temperature-rise softening effect into the fine blanking technology, thereby reducing the fine blanking difficulty of the high-strength steel plate; the metal material is heated to rise in temperature and expand by utilizing the electrothermal effect, the defect that the hydrostatic stress of a metal material shearing area is reduced too fast in the middle and last stages of blanking is overcome, and the capacity of inhibiting the cavity initiation-expansion of the shearing area is improved; by a timely and proper pulse current action mode and a loading method, aiming at a local area of a shear band which is easy to generate holes and microcracks in the blanking process, current energy is injected timely, high-density and concentrated to heal the holes and microcracks, the strain damage is repaired, the phenomenon that the strain damage is further developed into a macroscopic crack is avoided, a rough tearing band on a fine blanking section is finally formed, and the possibility of more widely applying the fine blanking to high-strength type materials is provided.
Description
Technical Field
The invention relates to a technology in the field of high-strength plate processing, in particular to a pulse current loading method in a fine blanking process.
Background
Due to the rapid development of the aerospace, aviation and automobile industries, higher requirements are put forward on the performances of reducing the self weight of a carrying platform, improving the fuel utilization rate, reducing pollution, improving the safety of the platform and the like. The high-strength steel plate has the advantages of high strength-ductility product, high specific strength, high collision absorption performance and the like, is concerned by various aerospace and automobile manufacturing industries, and is widely applied to various manufacturing fields of aerospace, military weapons, vehicle machinery and the like.
The blanking is the most economical necessary process and the necessary link in the machining industry, wherein the precision blanking part has the advantage of high forming precision, a 100% smooth hardened end face can be obtained, the precision of the part after the fine blanking can reach the direct assembly precision, the subsequent steps of grinding, polishing, precision inspection and the like which are necessary in the conventional traditional blanking are not needed, the production efficiency is obviously improved, and the production cost is reduced. However, at present, the method is mainly limited to metal materials with low strength and good ductility, and cannot be applied to steel plates with higher strength and hardness, so that the application and popularization of fine blanking in the stamping process of high-strength steel plates are greatly limited.
In patent "electric auxiliary blanking device and method" (application publication No. CN 108237171a), a rubber block is pressed downward by an upper die to apply a blank holder force, but the problems in practical use are as follows: at the initial stage of just contacting the metal material and blanking the metal material by the male die, the requirement of enough blank pressing force for pressing the metal material is urgently needed, a stable semi-closed space is formed for the metal material in a shearing area, a high enough hydrostatic stress state is established for the metal material near a blanking cutting edge, the metal material in the blanking cutting area is straightened, the problem of high collapse angle height and high width of the shearing end face is avoided/inhibited, meanwhile, the initiation and expansion of cavities and microcracks in the metal material shearing area are avoided/inhibited, and further, the formation of macroscopic cracks (tearing strips) on the end face after blanking is avoided/inhibited. However, in the prior art, the blank holder force is increased as the depth of the punch into the metal material is increased. In the above patent, the blank holder force on the surface near the metal material shear band is zero just when the male die contacts the metal material; even in the initial stage of punching metal material by a male die, there is a problem that the blank holder force is significantly too small. Therefore, the initiation of cavities and microcracks in the metal material shearing band is easily caused, and the problem that the proportion of the tearing band with rough upper surface of the blanking end face is overlarge after the blanking is finished is caused.
Disclosure of Invention
The invention aims to solve the technical problem that the existing fine blanking technology is insufficient in blanking capability on a high-strength steel plate.
In order to solve the technical problems, the invention provides the following technical scheme:
a current loading method in pulse current auxiliary fine blanking processing comprises the following steps:
step one, in a pulse current assisted fine blanking processing device, adding a blank holder made of insulating ceramics on the other side surface of the contact surface of a metal material to be processed and a female die flange part, so that in the process of blanking the metal material by a male die, the female die flange part is combined to apply compressive stress on the surface of the metal material, and thus high-amplitude hydrostatic stress is established in a shearing area of the metal material to be processed;
furthermore, the current loading method provided by the invention is suitable for the technical processing process of the metal material with shear deformation;
testing the forming strain limit of the metal material before the metal material is processed by using the pulse current auxiliary fine blanking processing device, and providing parameter information for the time of energization excitation;
further, the strain limit test includes strain hardening and strain damage of a metal material, and the like.
And step three, turning off a power switch, and connecting an electrode of the high-frequency pulse current power supply with relevant parts of the processing device according to the principle that the current flowing through the regional route is the convex die cutting edge, the metal material shearing area and the concave die cutting edge, or vice versa, so as to realize the regulation and control of the current flow direction.
Further, positive and negative electrodes of a power supply are respectively communicated with the male die and the female die;
furthermore, two poles of a power supply are respectively communicated with the metal material and the convex die, or the metal material and the concave die;
step four, according to the parameter information in the step one, when the metal material is in a state that the self forming performance tends to be consumed to the limit in the forming and processing process, a power switch is turned on, high-frequency pulse current excitation is started, the skin effect of high-frequency current is utilized, the amplitude of the limited current is highly concentrated in a deformation area determining the forming of the metal material, the current density of the deformation area is improved, and primary current loading in pulse current auxiliary fine blanking processing is completed;
fifthly, turning off a power supply, carrying out microscopic observation on the metal material shear band, determining the damage degree, and determining the descending quantity, the pulse current intensity and the electrifying time length of the male die in the processing die during the next blanking according to the damage degree;
and sixthly, repeatedly iterating according to the fourth step and the fifth step, continuously adjusting the downlink quantity, the current density, the frequency and the conduction time length of the male die in the processing die, finally obtaining a current loading mode which can obviously reduce the blanking force of the male die of the processing die and finally repair the damage of the metal material shearing area in real time.
The effective benefits of the invention over the prior art are as follows:
1. before the current loading method in the pulse current auxiliary fine blanking processing is implemented, firstly, a die for processing a metal material is improved, and a blank holder made of an insulating ceramic material is additionally arranged, wherein the blank holder has the characteristics of excellent toughness and hardness balance, and is different from a common die for processing. The excellent toughness of the blank holder can ensure that the blank holder can resist larger impact vibration load in the use process of processing equipment; the excellent strength of the blank holder ensures that the blank holder can absorb larger external load energy before breaking; the balance of these two characteristics becomes critical to ensure proper use of the ceramic blankholder. The excellent electrical insulation performance ensures that the current flows from the male die to the metal material shearing area and finally to the female die, or from the female die to the male die through the metal material shearing area, and if no ceramic blank holder with comprehensive excellent mechanical property and electrical insulation performance exists, the current flow direction regulation cannot be realized.
2. In the prior art, the power supply is continuously switched on in the whole processing process, electric excitation is continuously applied to metal materials (blank materials or semi-formed parts), and the influence caused by the time of electrification is not considered. The invention provides that before the metal material is molded, the molding strain limit of the metal material is tested, and the metal material is ensured to be in the self-molding performance in the molding process according to the test information. When the power is consumed to the limit state, the high-frequency pulse current excitation is started, so that the purpose of fully using the power of the power supply is achieved. The method has the advantages that the problem of reduction/degradation of the forming performance of the metal material caused by electrifying temperature rise is avoided as much as possible, the total amount of the method can reduce the electric heating effect (caused by changing the quality) concurrent in the electric excitation process, and the problems of metal oxidation rusting, annealing softening, uneven hardness and the like caused by obvious temperature rise of the metal material due to long time delay in the electric excitation process are effectively reduced. Compared with the prior art, the method has the obvious advantage of higher opportunity precision.
3. The invention adopts a high-frequency pulse current power supply, and the current has obvious skin effect (or called skin effect) when flowing through the conductor of the metal part, namely the current density is obviously larger than the superficial layer of the conductor of the metal part in the surface area of the conductor, and no current even exists in the conductor. The current flowing area route adopted by the invention is the convex mould cutting edge, the metal material shearing area and the concave mould cutting edge, or vice versa, so that the limited current density is highly concentrated in the metal material shearing deformation area which determines the quality of the part after the metal material is formed and processed, and the area which has no obvious quality influence on the part after the part is formed and processed is basically not distributed with any power supply energy. Compared with the prior art that the method and the mode that the metal material is directly connected with the anode and the cathode of the power supply and the current is distributed on the surface of the whole metal material are adopted, the energy efficiency utilization efficiency and the space accuracy are greatly improved, and the better capability of repairing and healing the strain damage area can be realized on the premise of limited power supply power.
4. The current loading mode provided by the invention is suitable for the technical processing process of the metal material with shear deformation. The shear deformation of the metal material is a process that entails the gradual reduction of the cross-sectional area of the metal material in a certain dimension, and the process is usually accompanied by strain hardening and strain damage of the metal material. When strain hardening and strain damage development accumulate beyond the relevant thresholds, the metal material will fracture, crack formation and propagation merging consistent with overall cracking and fracture. The current loading mode provided by the invention utilizes the characteristic that the cross section area of the material is gradually reduced in the processing process to improve the current density of the local position of the part quality in the zero molding process of the metal material, improve the accuracy of the current utilization space domain, further improve the overall effect and efficiency of the current action, slow down or even eliminate the progress of strain hardening and strain damage, namely obviously improve the molding and processing capacity of the material on the premise of not changing the type, heat treatment state and strain strengthening level of the metal material, ensure that the service performance of the material is not weakened after molding, and obviously relieve the contradiction between the processing performance and the service performance of the material.
Drawings
FIG. 1(a) is a schematic view of the general assembly of an improved tooling mold in an embodiment of the present invention;
FIG. 1(b) is an enlarged partial schematic view of the present invention; (H: depth of punch into metal material; direction of current: punch to die)
FIG. 1(c) is an enlarged partial schematic view of the present invention; (H: depth of punch into metal material; direction of current: die to punch)
FIG. 1(d) is an enlarged partial schematic view of the present invention; (H: depth of punch into metal material; direction of current: end to end of metal material)
Fig. 2 is a flow chart of an implementation process of the embodiment of the invention.
Wherein: 1-upper insulating plate, 2-backing plate, 3-male die fixing plate, 4-blank holder, 5-female die sleeve, 6-positioning pin, 7-female die, 8-small backing plate, 9-hollow backing plate, 10-reverse top spring, 11-bolt, 12-cushion block, 13-lower insulating plate, 14-small washer, 15-blank holder spring, 16-bolt, 17-small washer, 18-ejector rod, 19-fixing screw and 20-male die.
Detailed Description
The electric current of the invention acts on metal and has electric heating effect and electro-plasticity, and the eddy current effect of the high-frequency pulse current acting on the cavity and the microcrack has the capability of healing the metal plastic strain damage. In view of the fact that the pulse current assisted plastic forming process can obviously reduce the strength of the metal material and comprehensively improve the forming performance and the machinability of the metal material, the invention introduces the electro-plasticity, the repair and healing capacity of the pulse current to the cavities and microcracks in the metal material and the electric heating temperature rise softening effect into the fine blanking technology, and reduces the fine blanking difficulty of the high-strength steel plate; the metal material in the area near the blanking edge is heated and heated to expand by the electrothermal effect, so that the defect that the hydrostatic stress of the metal material shearing area is reduced too fast in the middle and last stages of blanking is relieved, and the capacity of inhibiting the cavity initiation-expansion in the shearing area is improved; by means of a proper pulse current acting mode and a proper loading method, aiming at a local area of a shear band which is easy to generate holes and microcracks in the blanking process, current energy is injected timely, densely and intensively to heal the holes and the microcracks, the strain damage is repaired, the phenomenon that the strain damage is further developed into a macroscopic crack is avoided, a rough tear band on a fine blanking section is finally formed, and the possibility that the fine blanking is more widely applied to high-strength type materials is provided. The invention is explained in further detail below with reference to the figures and the specific embodiments.
As shown in fig. 1(a), the improved processing mold in this embodiment is specifically assembled as follows, and an upper insulating plate 1, a backing plate 2, a punch fixing plate 3, a fixing screw 19, a punch 20, a blank holder 4, a die sleeve 5, a positioning pin 6, a die 7, a push rod 18, a small backing plate 8, a small gasket 17, a hollow backing plate 9, a reverse ejection spring 10, a bolt 16, a bolt 11, a blank holder spring 15, a small gasket 14, a cushion block 12, and a lower insulating plate 13 are sequentially arranged from top to bottom.
Wherein: the male die 20 is matched with the cavity of the blank holder 4, the backing plate 2, the male die fixing plate 3 and the male die 20 are matched and fixed through the fixing screw 19, the female die 7 is in interference fit with the female die sleeve 5, the ejector rod 18 is matched with the inner cavity of the female die 7, the bolt 16 is matched with the through hole of the blank holder 4 and the female die sleeve 5, the screw 16 is matched with the inner cavities of the blank holder 4, the female die sleeve 5, the cushion block 12 and the small backing plate 8,
the blank pressing force spring 15 is matched with the cavity of the hollow cushion plate 9 and the cavity of the cushion block 12, the bolt 11 is fixedly connected with the hollow cushion plate 9 through threads, the bolt 16 is matched with the blank pressing force spring 15, and the reverse ejection spring 10 is matched with the cavities of the small cushion plate 8 and the hollow cushion plate 9.
The male die 20 comprises a fixing part and a blanking part, the fixing part and the blanking part are integrally rectangular in cross section, and the guide part of the male die 20 is arranged in the blank holder 4 and is in sliding fit with the inner surface of the cavity of the blank holder 4. The male die 20 is over against the cavity of the female die 7, the male die 20 is arranged above the female die 7 and the ejector rod 18, and the blanking part of the male die 20 is matched with the cavity wall of the female die 20 in a clearance fit manner; the ejector rod 18 is arranged in the cavity of the female die 7, the surfaces of the ejector rod 18, which are in contact with each other, form sliding fit adaptation, and the male die 20 and the ejector rod 18 can smoothly slide up and down; the blanking part of the male die 20 is arranged right below the center of the fixing part, the cross section size (radial size) of the male die at the position of the blanking end of the male die 20 facing the direction of the fixing part and a distance from the thickness of one metal material is smaller than the cross section size of the end face of the blanking part, and the surface of the blanking part is coated with an insulating coating; the ejector rod 18 is matched with the blanking part of the male die 20 to penetrate out of the blank holder 4 so as to realize blanking of the metal material to be formed; the shape of the female die 7 is cylindrical, and the female die 7 is arranged in the cavity of the female die sleeve 5 and forms interference fit with the cavity of the female die sleeve 5.
As shown in fig. 1(a), the male die 20 and the metal material are respectively connected to two electrode phases of a power supply, and the metal material to be punched is disposed below the blanking portion of the male die 20 and the blank holder 4, and above the female die 7 and the ejector pin 18.
As shown in fig. 1(a), the lower part of the jack 18 is in contact with the anti-jack spring 10 through a small spacer 17. The compression amount of the reverse ejection spring 10 determines the amplitude of the reverse ejection force on the small gasket 17 and the ejector rod 18, and the compression amount of the reverse ejection spring 10 can be regulated and controlled by controlling the number of turns of the nut 1, so that the reverse ejection force of the ejector rod 18 on the metal material is always in a stable and controllable range in the blanking process.
As shown in fig. 1(a), the bolt 16 is disposed in the through hole inner cavity of the blank holder 4, the cavity die sleeve 5, the hollow pad plate 9, the small pad plate 8, and the pad 12, is fixedly connected with the blank holder 4 through a thread, and is matched with the through holes of the cavity die sleeve 5, the hollow pad plate 9, the small pad plate 8, and the pad 12. The blank-pressing force spring 15 is arranged in the cavities of the hollow backing plate 9 and the cushion block 12, and the blank-pressing force spring 15 is respectively matched with the bolt 16, the small gasket 14, the hollow backing plate 9 and the cushion block 12. The compression amount of the blank holder force spring 15 can be controlled by regulating the number of turns of the screwing bolt 16, and the blank holder force with stable amplitude is applied to the metal material by the blank holder 4 in the blanking process through the fixed connection of the bolt 16 and the blank holder 4, and is kept at a constant horizontal value in the whole blanking process.
As shown in fig. 1(a), the number of the positioning pins 6 is two, and the positioning pins are arranged on two sides of the male die 20 and the female die 7; four sets of bolts 16, blank holder force springs 15 and small washers 14 are arranged at four corners of the die.
As shown in fig. 1(a), the positioning pin 6 is disposed in the through holes of the blank holder 4 and the cavity die set 5, and is matched with the through holes of the blank holder 4 and the cavity die set 5. The small gasket 17 and the reverse top spring 10 are arranged in the cavities of the small cushion plate 8 and the hollow cushion plate 9 and are matched with the cavities of the small cushion plate 8 and the hollow cushion plate 9, so that the small cushion plate and the hollow cushion plate can smoothly slide and stretch up and down. The bolt 11 is arranged in the cavity of the cushion block 12 and is in threaded connection with the cavity of the hollow cushion plate 9.
Referring to fig. 1(a), further, the fixing screw 19 is arranged in the through holes of the backing plate 2 and the punch retainer 3 near the end of the punch 20 and fixed in the through hole of the backing plate 2 at the end of the punch 15; the base plate 2 and the punch fixing plate 3 fix the punches through fixing screws 19.
A flow of a pulse current loading method in fine blanking processing is shown in fig. 2, and the method comprises the following steps:
s1: and placing the metal material to be formed on the female die 7 and the female die sleeve 5, and laying insulating films on the upper surface and the lower surface of the metal material to be punched. And arranging a flexible polymer pressure sensor on a contact interface of the blank holder 4 and the metal material, which is close to the blanking and shearing area of the metal material, so as to monitor the variation curve of the blank holder force along with the time domain in the blanking process.
S2: the blank holder 4 is fixedly connected with the female die sleeve 5 through a positioning pin 6, so that the metal material to be punched is pressed; and mounting the blank holder force spring 15 and the small washer 14 on a bolt 16, and then mounting the blank holder force spring 15, the small washer 14 and the bolt 16 in a cavity formed by the blank holder 4, the concave die sleeve 5, the hollow cushion plate 9, the cushion block 12 and the small cushion plate 8 together to fixedly connect the bolt 16 with the blank holder 4.
S3: the control of the compression amount of the bolt 16 and the released elastic force of the bolt is realized by controlling the number of turns of screwing the bolt 16, and the regulation and control of the blank holder force of the blank holder 4 on the metal material to be punched are further realized by the fixed connection of the bolt 16 and the blank holder 4, so that the blank holder force is kept at a stable horizontal value.
S4: and the ejector rod 18, the small gasket 17, the reverse ejection spring 10 and the bolt 11 are assembled in the cavities of the female die 7, the small cushion plate 8, the hollow cushion plate 9 and the cushion block 12. The compression amount of the reverse ejection spring 10 is regulated and controlled by regulating and controlling the number of turns of screwing the bolt 11, so that the reverse ejection force of the ejector rod 18 on the metal material to be punched is regulated and controlled, the reverse ejection force is kept at a set horizontal value before punching is started, and the reverse ejection force is stably increased within a certain range in the whole metal material punching process.
S5: and connecting the punch retainer 3, the backing plate 2 and the fixing screws 19 with the punch 20, and then fitting the punch 20 into the cavity of the blank holder 4 to form sliding fit.
S6: the male die 20 and the female die sleeve 5 are respectively connected to two poles of a pulse power supply.
S7: the blank holder 4 compresses the metal material, after blank holder force is applied to the metal material, the ejector rod 18 applies ejection force to the metal material, and after high-level hydrostatic stress is established in the metal material shear strain area, the male die 20 moves downwards, so that the metal material is blanked. The press machine presses and descends the upper insulating plate 1 and the base plate 2 to apply pressure to the male die 20, and the requirement of the male die 20 on the punching force in the process of punching the metal material to be punched is met.
S8: starting from the fact that the metal material is pressed by the male die 20, the male die 20 punches the metal material downwards, and the time domain curves of the blanking force and the blank holding force of the male die 20 are monitored. When the punch blanking force is increased to a degree that the die is seriously abraded, or the time domain curves of the blanking force and the blank holder force obviously and locally fluctuate, the descending displacement of the punch 20 at the moment is recorded. Then, the punch 20 moves upward to return to the starting position, and the blank holder 4, the punch 20, the positioning pin 6, the bolt 16, and other related accessories are removed to take out the punched metal material.
S9: and observing the microstructure of the sheared area of the metal material to determine the development degree of the damage. And continuously reducing the descending displacement of the male die 20 along with the increase of the test blanking times, and determining the development degree of the cavities and microcracks of the shear band corresponding to different descending displacements of the male die 20 according to the iteration of the experimental process.
S10: as described above, the insulating films are applied on the upper and lower surfaces of the metallic material to be punched, and then the metallic material to be punched is again disposed between the male die 20 and the female die 7, and the relevant die parts are assembled, and the blank-holding force and the counter-pressing force are applied to prepare the male die 20 to punch the metallic material to be punched again. And the male die 20 punches the metal material to be punched under the action of the downward pressing head of the press, and monitors the blanking force time domain curve of the male die 20 and the blank holder force time domain curve of the blank holder force.
S11: and (4) according to the above process, repeating iteration, and sequentially reducing the descending amount of the male die 20 in the experiment to obtain the corresponding relation between the descending displacement amount of the male die 20 and the damage degree of the metal material shear band.
And S12, preselecting the descending displacement of a certain male die 20, stopping the descending of the male die 20 when the descending displacement of the male die 20 reaches the preselecting descending displacement, then switching on a power switch to enable current to be conducted through a region, close to the outer edge of the cutting edge of the male die 20, in the shear strain region of the metal material, completing a current loop through the outer edge of the cutting edge of the male die 20, and switching off the switch at proper time to stop electrifying.
And S13, observing the microstructure of the metal material shear strain area to determine the damage repair condition. Based on the above, determining the descending amount, the pulse current intensity and the electrifying time length of the male die 20 in the next blanking, and performing iterative optimization until the damage of the metal material shearing area is repaired to the continuous descending blanking without affecting the male die 20.
S14: and re-blanking the metal material according to the flow. And (3) blanking the metal material by the male die 20, and if the blanking force of the male die 20 is too large or the time domain curve of the blanking force/blank holder force fluctuates locally, switching on the switch again to repair the damage of the shearing area by the pulse current, so that the damage of the shearing area is not developed into a macrocrack in the subsequent blanking.
S15: through the steps, the descending amount, the current density, the frequency and the conducting time length of the male die 20 when the pulse current is connected are optimized, the current applying mode which can remarkably reduce the blanking force of the male die 20 and repair the damage of the metal material shearing area in real time is finally obtained, and when the descending amount of the male die 20 reaches the plate thickness of the metal material, the fine blanking end face of a 100% bright and clean belt can be obtained. Thereafter, the punch 20 ascends to a blanking start position. In the upward process of the male die 20, fine blanking parts are ejected out of a cavity of the female die 7 by the ejector rod 18, and the fine blanking parts are lifted to the initial position before the blanking of the metal material is started, so that a complete blanking process is completed, and the fine blanking end face of a 100% smooth belt can be obtained under a low blanking force.
S16: the male die 20 and the blank holder 4 move upwards to the initial blanking starting position to prepare for the start of the next blanking action.
In the whole process, because the surfaces of the die blank holder 4, the concave die sleeve 5, the cushion block 12 and the hollow cushion plate 9 are covered or coated with insulating films or metal materials, current cannot leak, and the safety of workers is protected.
The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
In the patent of the invention, the high-frequency pulse current flow path is that a male die 20 is larger than a metal material and that a female die 7 is larger than a metal material. Because the skin effect exists in the high-frequency pulse current, the current density of the surface layers of the male die 20, the metal material and the metal material is higher than the deep layer part of the corresponding part, the current energy is more concentrated on the surface layer of the metal material, which is beneficial to timely repairing and even healing the cavity and the microcrack which are initiated and expanded on the surface of the metal material near the cutting edge of the male die 20, and the comparison of (b), (c) and (d) in the figure 1 shows that the influence area of the high-frequency pulse current flowing through the part is smaller, the surface of the metal material near the blanking cutting edge of the male die 20 which is easy to initiate the microcrack is more concentrated, and the current utilization efficiency is obviously higher than the low-frequency current.
Claims (5)
1. A current loading method in pulse current auxiliary fine blanking processing is characterized by comprising the following steps:
in the pulse current assisted fine blanking processing device, a blank holder made of insulating ceramics is additionally arranged on the other side surface of the contact surface of a metal material to be processed and a female die flange part, so that in the process of blanking the metal material by a male die, the female die flange part is combined to apply compressive stress to the surface of a plate material, and thus, high-amplitude hydrostatic stress is established in a shearing area of the metal material to be processed;
testing the forming strain limit of the metal material before the metal material is processed by using the pulse current auxiliary fine blanking processing device, and providing parameter information for the time of energization excitation;
step three, turning off a power switch, and connecting an electrode of a high-frequency pulse current power supply with relevant parts of a processing device according to the principle that a current flowing area route is a convex die cutting edge, a metal material shearing area and a concave die cutting edge, or vice versa, so as to realize the regulation and control of the current flow direction;
fourthly, establishing high-amplitude hydrostatic pressure according to the shearing area in the first step, turning on a power switch when the metal material is in a state that the self-forming performance tends to be consumed to a limit state in the forming and processing process, starting high-frequency pulse current excitation, and utilizing the skin effect of high-frequency current to enable the limited current amplitude to be highly concentrated in a deformation area determining the metal material forming, so that the current density of the deformation area is improved, and primary current loading in pulse current auxiliary fine blanking processing is completed;
fifthly, turning off a power supply, carrying out microscopic observation on the metal material shear band, determining the damage degree, and determining the descending quantity, the pulse current intensity and the electrifying time length of the male die in the processing die during the next blanking according to the damage degree;
and sixthly, repeatedly iterating according to the fourth step and the fifth step, continuously adjusting the downlink quantity, the current density, the frequency and the conduction time length of the male die in the processing die, continuously optimizing the blanking force of the male die of the processing die, and finally obtaining a current loading mode for repairing the damage of the metal material shearing area in real time and in time.
2. The method of claim 1, wherein the strain limit test in the second step includes strain hardening and strain damage of the metal material.
3. The method for loading current in a pulse current assisted fine blanking process according to claim 1, wherein the high frequency pulse current power source electrode in the third step is connected in such a manner that the positive and negative electrodes are respectively communicated with the male die and the female die.
4. The method for loading current in pulse current assisted fine blanking according to claim 1, wherein the high frequency pulse current power supply electrode in step three is connected in such a manner that two poles of the power supply are respectively connected to the sheet and the punch, or the sheet and the die.
5. The method for applying current in a pulse current assisted fine blanking process according to any one of claims 1 to 4, wherein the blanking metal material is a process of a metal material having shear deformation.
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Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203610443U (en) * | 2013-09-02 | 2014-05-28 | 徐州工程学院 | Device for utilizing pulse current to restore plate plastic deformation damages |
| JP2014188553A (en) * | 2013-03-27 | 2014-10-06 | Daihatsu Motor Co Ltd | Method of determining quality of cut surface by die-cutting process |
| CN106513508A (en) * | 2016-09-23 | 2017-03-22 | 北京航空航天大学 | Titanium alloy sheet metal part cold-die hot-stamping forming tool and machining method |
| CN108237171A (en) * | 2016-12-26 | 2018-07-03 | 上海交通大学 | Electricity auxiliary blanking apparatus and method |
| CN108405727A (en) * | 2018-03-21 | 2018-08-17 | 哈尔滨工业大学 | A kind of sheet metal pulse current auxiliary Micro-bending device and method |
| CN108405713A (en) * | 2018-03-21 | 2018-08-17 | 哈尔滨工业大学 | A kind of sheet metal pulse current assists micro- hole punched device and method |
| CN109821966A (en) * | 2019-03-04 | 2019-05-31 | 武汉理工大学 | Plasticising fine-punching formation process design method based on crack initiation control |
-
2019
- 2019-08-16 CN CN201910757804.9A patent/CN110369600B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014188553A (en) * | 2013-03-27 | 2014-10-06 | Daihatsu Motor Co Ltd | Method of determining quality of cut surface by die-cutting process |
| CN203610443U (en) * | 2013-09-02 | 2014-05-28 | 徐州工程学院 | Device for utilizing pulse current to restore plate plastic deformation damages |
| CN106513508A (en) * | 2016-09-23 | 2017-03-22 | 北京航空航天大学 | Titanium alloy sheet metal part cold-die hot-stamping forming tool and machining method |
| CN108237171A (en) * | 2016-12-26 | 2018-07-03 | 上海交通大学 | Electricity auxiliary blanking apparatus and method |
| CN108405727A (en) * | 2018-03-21 | 2018-08-17 | 哈尔滨工业大学 | A kind of sheet metal pulse current auxiliary Micro-bending device and method |
| CN108405713A (en) * | 2018-03-21 | 2018-08-17 | 哈尔滨工业大学 | A kind of sheet metal pulse current assists micro- hole punched device and method |
| CN109821966A (en) * | 2019-03-04 | 2019-05-31 | 武汉理工大学 | Plasticising fine-punching formation process design method based on crack initiation control |
Non-Patent Citations (3)
| Title |
|---|
| 2024T4铝合金板材脉冲电流辅助冲裁实验研究;杜浩;《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》;20190215;B022-134 * |
| 板材自阻加热成形中电流的热效应与极性效应研究进展;张凯锋;《锻压技术》;20180731;第43卷(第7期);第71-89页 * |
| 镁合金及先进高强钢电脉冲辅助塑性成形性能研究;解焕阳;《中国博士学位论文全文数据库 工程科技Ⅰ辑》;20170215;B022-110 * |
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