CN117772880A - Dot matrix voltage-conducting edge forming process for electric auxiliary forming - Google Patents
Dot matrix voltage-conducting edge forming process for electric auxiliary forming Download PDFInfo
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Abstract
The invention discloses a dot matrix conductive voltage edge forming process of electric auxiliary forming, which is applied to a dot matrix conductive blank pressing die of electric auxiliary forming, and the die is applied to a hydraulic press with multiple power outputs, and comprises the following steps: (1) setting process parameters; (2) clamping the plate material; (3) a current distribution arrangement; (4) electrifying and heating; (5) regional edge pressing; (6) stamping and forming; (7) low Wen Baoya; (8) taking out the sample. The die and the forming process can realize the effects of non-uniform electrifying in areas and changing the instantaneous current distribution of the plate in the forming process through the lattice electrode conduction, and effectively solve the defects of local instability wrinkling, excessive thinning and the like in the electrically assisted forming process of the thin-wall asymmetric special-shaped structure, thereby improving the forming quality and precision.
Description
Technical Field
The invention relates to the technical field of metal plastic processing and forming, in particular to a dot matrix voltage-conducting edge forming process of electric auxiliary forming.
Background
With the development of aerospace and petrochemical fields in China, the demands of large-scale thin-wall annular shell components represented by the annular shell transition section of the underwater vehicle are greatly increased in various fields. Such as main bearing structural members of the underwater submarine vehicle annular shell transition section, the pressure-resistant annular shell and the like, the annular shell of the large-size upper-level fuel storage tank, and large-size thin-wall structures of pressure-bearing pipelines, oval heads and the like of a multi-section reactor in an oil and gas device. The components are mostly made of difficult-to-deform alloy (titanium alloy, high-strength stainless steel and the like) and thin-wall asymmetric special-shaped structures, have the problems of large deformation resistance and low forming limit in the forming process represented by drawing, bending and other processes, and are easy to generate obvious uneven deformation and various forming defects. The main embodiments are as follows: the outer edge is easy to crack and excessively thin when being pulled, the inner edge is easy to unstably wrinkle when being pressed, and the forming quality is difficult to control.
The electric auxiliary forming process comprises the steps of self-resistance heating, current-carrying forming, electric treatment after forming and the like, and is paid attention to because of the advantages of convenience, energy conservation, high efficiency and the like, and in recent decades, many researches show that the joule heating effect and the electro-plastic effect of current excitation can improve the formability of difficult-to-deform materials, and the production period of a component can be greatly shortened by rapid self-resistance heating; in addition, the post-forming load-retaining electrical treatment can reduce residual stress and residual deformation by inducing electrical stress relaxation, the forming precision and quality of the member can be obviously improved, and the method has wide application prospect in the field of material forming. The method is applied to the fields of automobiles and aerospace at present, the thinning rate of parts and the deformation resistance in the forming process are effectively reduced, and the rebound and the like of formed parts are effectively controlled. And reports that the application of current plastic deformation is also beneficial to dislocation movement, diffusion phase transformation and the like. However, since current loading in the current electric auxiliary forming process is mainly to uniformly load the plate by using the conductive electrode, current distribution cannot be actively regulated. Particularly, the electric auxiliary forming is mainly applied to small-sized and regular-shaped components, and the application of the electric auxiliary forming to large-sized and asymmetric complex components is rarely reported because the change of the geometric shape of the components and the change of the contact condition of the components and the mould lead to the complex and changeable distribution of the electric field and the temperature field in the components and finally the difficulty in controlling the forming precision.
Disclosure of Invention
In order to solve the technical defects in the prior art, the invention provides a pulse current auxiliary and partition blank pressing deep drawing forming technology based on domain regulation, and provides an excellent scheme for forming a thin-wall asymmetric special-shaped structure by introducing currents with different densities into different forming areas and applying blank pressing forces with different magnitudes and locally non-uniform current fields of components and utilizing the non-uniform currents and the non-uniform blank pressing forces.
In order to solve the technical problems, the invention adopts a technical scheme that:
the utility model provides an electrically assisted formed lattice conductive blank holder mould, includes the lower mould and is located the upper mould directly over the lower mould, the fixed stamping male die that is provided with in top surface of lower mould, set up the stamping die that cooperatees with the stamping male die on the bottom surface of upper mould, but the top of lower mould is provided with vertical lift and the insulating blank holder of movable sleeve setting in stamping male die outside, the top surface of insulating blank holder is provided with the blank holder that is formed by the movable concatenation of a plurality of regional blank holders, be provided with the draw bead arch on the top surface of blank holder, offered the draw bead recess with the cooperation of draw bead arch on the bottom surface of upper mould;
a plurality of region edge pressing blocks are movably embedded in the bottom surface of the upper die, each region edge pressing block is respectively and correspondingly positioned above the joint of two adjacent region edge pressing plates, and the top end of each region edge pressing block can apply independent jacking force;
the top surface both sides of insulating pressure flitch set up the electrically conductive subassembly of dot matrix respectively, the electrically conductive subassembly of dot matrix includes the fixed plate of liftable connection on insulating pressure flitch, sets up in the electrode plate of fixed plate top, and threaded connection has a plurality of screw electrode on the electrode plate, and the bottom of screw electrode can contact or separate with the fixed plate, and after the sheet material of waiting to take shape was fixed the centre gripping, the edge and the fixed plate electrical contact of sheet material, through setting up the quantity and the position distribution of the screw electrode that contacts with the fixed plate on the electrode plate, adjustable current density and the position distribution in the sheet material is introduced by the electrode plate.
Further, the top of the upper die is fixedly connected with a connecting base plate.
Further, a pushing block is movably arranged in the upper die, and when the pushing block is completely positioned in the upper die, the bottom surface of the pushing block and the surface of the stamping forming female die are smooth and excessive.
Further, the caulking groove has been seted up to the top surface of insulating blank holder, the blank holder is inlayed and is located the caulking groove, and the medial surface of blank holder slides the laminating with the side of stamping forming terrace die, and the top surface of blank holder and the top surface of insulating blank holder are located same horizontal plane.
Further, a plurality of guide posts which movably penetrate through the insulating pressing plate are fixedly arranged on the top surface of the lower die.
Further, the edge of the insulating pressing plate is rotationally connected with an adjusting screw, and the top of the adjusting screw is in threaded connection with the fixing plate.
Further, a plurality of plug-in posts which are arranged corresponding to the screw type electrodes are arranged on the top surface of the fixed plate.
The dot matrix voltage-conducting edge forming process of the electric auxiliary forming comprises the following steps:
(1) And (3) process parameter setting: setting parameters of the output force of a pulse power generator and each power output end according to the forming technological parameters of the plate to be formed;
(2) And (3) clamping the plate: lifting the fixing plates at two sides, accurately placing the plate to be punched on the top surface of the insulating pressing plate, and then descending the fixing plates at two sides to ensure that the fixing plates are reliably contacted with the edges of the plate;
(3) Current distribution setting: according to the optimal technological parameters obtained by the simulation forming of the plate, the number and position distribution of screw type electrodes on the electrode plate, which are contacted with the fixed plate, are regulated;
(4) And (3) electrifying and heating: forming operation current with preset power and current magnitude is fed into the electrode plate through the pulse power supply generator and is continued for a preset time period, so that the plate is heated to a preset forming temperature;
(5) Zoned edge pressing: the upper die descends and is matched with the insulating pressing plate to clamp the plate, the hydraulic power output end at the top provides vertical downward edge pressing force for the edge pressing blocks in each region, and the hydraulic power output end at the bottom provides vertical upward back pressing force for the insulating pressing plate;
(6) And (3) stamping and forming: the upper die continues to descend, and the stamping male die and the stamping female die are matched to finish the forming processing of the plate;
(7) Low Wen Baoya: after stamping is completed, a pulse power supply generator is used for supplying pressure maintaining operation current with preset power and current to the electrode plate, and the operation current is kept for a preset time period and pressure maintaining;
(8) Taking out the sample: and the insulating pressing plate and the upper die synchronously move upwards, the punched workpiece is separated from the punch forming male die, and then the workpiece is taken out of the upper die.
Further, before the plate is clamped, oil stain treatment and finishing treatment are carried out on the surfaces of the plate, the upper die, the lower die, the stamping male die and the stamping female die so as to ensure the subsequent clamping effect, and after the plate is cut into a target shape, high-temperature-resistant lubricating conductive coating is sprayed on the surface of the plate.
Further, in the step (4), the process parameters of the forming operation current are as follows: the current frequency is 500Hz, and the current density is 40-50A/mm 2 The duty ratio is 5%, and the preset forming temperature is 600-800 ℃.
Further, in the step (7), the process parameters of the holding operation current are as follows: the current is 10A/mm 2 ～20A/mm 2 The pressure maintaining time is 600-1200 s.
Further, after step (8), a wrinkling and thinning precision test is required for the formed piece.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention adopts an electric auxiliary forming technology, controls the spatial distribution of current through the dot matrix type partition conduction, and realizes the local softening condition of a forming area, thereby reducing the forming load and solving the problems of high forming force and difficult forming of the thin-wall asymmetric special-shaped structure.
(2) According to the special-shaped characteristics of the formed piece, the invention can be used for feeding differential current with different densities into different forming areas to assist in heating, applying different blank holding forces by matching with different forming areas, and actively utilizing the non-uniformity to realize the uniform forming of the thin-wall asymmetric special-shaped structure.
(3) By applying the electrically assisted forming lattice conductive edge pressing die and the forming process method, the lattice partition conduction can be used for realizing partition nonuniform energization and changing the effect of instantaneous current distribution of the plate in the forming process, and the defects of local instability wrinkling, excessive thinning and the like in the electrically assisted forming process of the thin-wall asymmetric special-shaped structure are effectively overcome, so that the forming quality and precision are ensured, and the high-quality forming of the thin-wall asymmetric special-shaped structure is realized.
Drawings
Fig. 1 is a schematic perspective view of a workpiece being processed using the die and forming process of the present invention.
Fig. 2 is a schematic perspective view of an electrically assisted forming conductive edge pressing die for a lattice according to the present invention.
Fig. 3 is a schematic perspective view of the lower die and its upper parts according to the present invention.
FIG. 4 is a schematic diagram showing a second perspective structure of the lower mold and its upper parts according to the present invention.
Fig. 5 is a schematic top view of the lower die and its upper parts of the present invention.
Fig. 6 is a schematic perspective view of the lattice conductive assembly of the present invention.
Fig. 7 is a schematic perspective view showing a state of assembling the lattice conductive assembly on the lower die.
Fig. 8 is a schematic perspective view of an insulating pressing plate according to the present invention.
Fig. 9 is a schematic perspective view of the upper die and its upper parts according to the present invention.
FIG. 10 is a schematic diagram showing a second perspective structure of the upper mold and its upper parts according to the present invention.
FIG. 11 is a flow chart of the electrically assisted forming process for forming a conductive edge of a lattice according to the present invention.
Fig. 12 is a schematic diagram of simulation results of current flowing into the plate in the divided areas in the embodiment.
In the figure: the die comprises a lower die 1, an upper die 2, a draw bead groove 201, a punch 3, an insulating pressing plate 4, a lower ejector rod 401, a fixing plate 5, a plug-in column 501, an electrode plate 6, a screw electrode 7, an edge pressing plate 8, a draw bead protrusion 801, a connecting backing plate 9, a pushing block 10, a guide column 11, a region edge pressing block 12, a pressing rod 121, a guide block 13 and a regulating screw 14.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making clear and defining the scope of the present invention.
As shown in FIG. 1, the workpiece processed by the electrically assisted forming lattice conductive blank holder die and the forming process is of an integral asymmetric hyperbolic shell structure, and consists of an upper arched curved surface main body and arched plane flanging with integral structures at two sides of the bottom end of the arched curved surface part, wherein the arched plane flanging is provided with a retaining rib. When the traditional grinding tool is used for direct stamping forming, the outer circle is easy to crack under the action of tensile stress, the inner circle is easy to wrinkle under the action of shearing stress, and particularly, the forming quality is difficult to control at the position with larger curvature change degree.
The lattice conductive edge pressing die is applied to a hydraulic machine with multiple power outputs, and the main power output of the hydraulic machine is used for providing uplink and downlink power for the upper die 2 so as to complete the stamping process and resetting of the upper die 2; the upper hydraulic power output end is used for providing independent and vertical downward blank pressing force for the region blank pressing block 12; the lower hydraulic power output is used for providing vertical upward back pressure for the insulating pressing plate 4 so as to complete the stamping forming operation of the workpiece in cooperation with the descending process of the upper die 2 and resetting of the insulating pressing plate 4.
Referring to fig. 2 to 10, an electrically assisted forming conductive edge pressing die for a lattice comprises a lower die 1 and an upper die 2 located right above the lower die 1, wherein a punch forming male die 3 is fixedly arranged on the top surface of the lower die 1, and a punch forming female die matched with the punch forming male die 3 is arranged on the bottom surface of the upper die 2. The space between the surface of the punch 3 and the punch cavity constitutes the forming space of the arcuate curved surface body of the workpiece. The bottom end of the punch forming male die 3 is an arc-shaped curved surface matched with the curved surface of the bottom surface (inner side) of the top of the workpiece, the bottom end is of a cylinder structure with a vertical side surface, and the bottom surface of the punch forming male die is fixedly connected to the top surface of the lower die 1 through bolts. The stamping male die 3 is a metal casting part, the inner side of the bottom of the stamping male die 3 is of a hollow shell structure so as to lighten the self weight of the stamping male die 3, and the hollow part is provided with criss-cross reinforcing ribs so as to ensure the integral strength of the stamping male die 3.
The top of the lower die 1 is provided with an insulating material pressing plate 4 (made of insulating materials) which can vertically lift and is movably sleeved outside the stamping forming male die 3, the top surface of the insulating material pressing plate 4 is provided with a blank holder 8 formed by movably splicing a plurality of area blank holders, the top surface of the blank holder 8 is provided with a draw bead protrusion 801, and the bottom surface of the upper die 2 is provided with a draw bead groove 201 matched with the draw bead protrusion 801; because the middle section of the workpiece is a long arc section, and the two ends of the workpiece are provided with obvious bending sections, in the embodiment, four blank holders 8 are arranged on each side of the workpiece, the joint of two adjacent blank holders 8 is correspondingly positioned in the middle of the long arc section of the workpiece and at two bending positions, and the joint of 6 blank holders on two sides corresponds to the turning positions of the outer circle and the inner circle of the workpiece. The top surface of the blank holder plate 8 clamps the two side edges of the plate to be formed with the bottom surface of the upper die 2, is used for stamping and forming the arc-shaped plane flanging of the workpiece, and meanwhile, the draw bead protrusion 801 is matched with the draw bead groove 201 to form the draw bead of the arc-shaped plane flanging, and simultaneously, the clamping effect of the die on the plate edges can be improved.
As shown in fig. 7, an arc-shaped through hole is formed in the inner side of the insulating pressing plate 4, and the shape of the through hole is matched with the cross-sectional shape of the bottom end main structure of the punch forming male die 3, so that the insulating pressing plate 4 can be movably sleeved on the outer side of the punch forming male die 3. A plurality of lower ejector rods 401 which penetrate through the lower die 1 and are uniformly distributed are fixedly connected to the bottom surface of the insulating material pressing plate 4, the lower ejector rods 401 are fixedly connected to the hydraulic power output end at the bottom, the insulating material pressing plate 4 can be driven to vertically lift through the hydraulic power output end, and back pressure is provided in the forming process. Guide posts 11 are fixedly arranged at four corners of the top surface of the lower die 1 respectively, guide blocks 13 are fixedly embedded in four corners of the insulating pressing plate 4 respectively, the guide blocks 13 are correspondingly and slidably sleeved on the outer sides of the guide posts 11 respectively, and the insulating pressing plate 4 is guaranteed to stably and reliably vertically lift through sliding fit between the guide blocks 13 and the guide posts 11, so that the plate is synchronously clamped everywhere in the clamping process. In the stage of clamping the plate material for forming the workpiece, the insulating material pressing plate 4 is positioned at the highest position, and at the moment, the top surface of the insulating material pressing plate and the highest point of the stamping forming male die 3 are positioned in the same horizontal plane or higher than the highest point of the stamping forming male die 3, so that the plate material is tiled on the top surface of the insulating material pressing plate 4, and the subsequent clamping and fixing of the plate material on the insulating material pressing plate 4 are completed.
The caulking groove has been seted up to the top surface of insulating pressure flitch 4, and blank holder 8 inlays and locates in the caulking groove, and the medial surface of blank holder 8 slides the laminating with the side of stamping forming terrace die 3, and the top surface of blank holder 8 and the top surface of insulating pressure flitch 4 are located same horizontal plane to guarantee the continuity of forming die surface shape. The edge pressing plate 8 adopts a movable splicing structure, so that the process requirement of partition pressurization is met; the movable embedding mode is adopted, so that the replacement is convenient, the forming requirements of different draw beads are met, and the universality of equipment is improved.
Dot matrix conductive assemblies are respectively arranged on two sides of the top surface of the insulating pressing plate 4, one dot matrix conductive assembly is connected with the positive electrode of an external power supply, and the other dot matrix conductive assembly is connected with the negative electrode of the external power supply. As shown in fig. 6, the lattice conductive assembly includes a fixed plate 5 connected to the insulating pressing plate 4 in a vertically adjustable manner, and an electrode plate 6 disposed above the fixed plate 5. Specifically, the edge of the insulating pressing plate 4 is rotatably connected with an adjusting screw 14, and the top of the adjusting screw 14 is in threaded connection with the fixing plate 5. The vertical height of the fixed plate 5 can be adjusted by the adjusting screw 14; before the sheet material is placed, the fixed plate 5 is in a lifting state, a gap is reserved between the bottom surface of the fixed plate and the top surface of the insulating pressing plate 4, after the sheet material is placed, the edge of the sheet material is positioned in the gap, and then the fixed plate 5 is lowered by rotating the adjusting screw 14 to clamp the edge of the sheet material, so that the fixed plate 5 and the sheet material can be in a good conductive state, and meanwhile, the sheet material is primarily clamped on the insulating pressing plate 4.
The electrode plate 6 is connected with a plurality of screw type electrodes 7 distributed in a linear matrix in a threaded manner, the bottom ends of the screw type electrodes 7 can be contacted with or separated from the fixed plate 5, after the plate to be formed is fixedly clamped, the edge of the plate is electrically contacted with the fixed plate 5, and the current density and the position distribution introduced into the plate by the electrode plate 6 can be adjusted by arranging the number and the position distribution of the screw type electrodes 7 contacted with the fixed plate 5 on the electrode plate 6. Preferably, a plurality of plugging posts 501 corresponding to the screw type electrodes 7 are arranged on the top surface of the fixed plate 5. When the screw type electrode 7 is screwed forward and extends downwards, the whole electrode plate 6 can be lifted upwards, and the bottom end of the part of the screw type electrode 7 which is not screwed forward is suspended above the fixed plate 5 and is in a non-connection state with the fixed plate 5, so that current inputs with different spatial distributions and different densities can be realized at different positions of the fixed plate 5 (the input electrodes are arranged on the electrode plate 6, all the screw type electrodes 7 are of parallel structures, the current flows from the electrode plate 6 are the same, the parallel number is larger, and the current density is larger), thereby realizing the input of corresponding current at the corresponding region of the plate; meanwhile, after the bottom ends of the screw type electrodes 7 are inserted into the inserting posts 501, the relative positions of the electrode plates 6 and the fixing plates 5 can be kept unchanged.
In this embodiment, except for the electrode plate 6, the screw-type electrode 7 and the fixing plate 5, the rest of the components are non-conductive (at least the surface is non-conductive, such as the surface of the mold is insulated by bakelite or mica), so that the current flowing area and direction can be controlled. Before the actual forming operation of the workpiece is performed, a current distribution corresponding to the shape of the workpiece is obtained through a simulation experiment and a limited number of actual forming experiments, so that before the electrode plate 6 is electrified, the position of each screw type electrode 7 (contacting or not contacting the fixed plate 5) is adjusted in advance to form a corresponding space lattice electrode distribution.
As shown in fig. 9 and 10, a plurality of region blank holder blocks 12 are movably embedded in the bottom surface of the upper die 2, each region blank holder block 12 is respectively and correspondingly positioned above the junction of two adjacent region blank holders, the top end of each region blank holder block 12 can apply independent top pressure, the bottom surface of the region blank holder block 12 and the bottom surface of the upper die 2 are positioned in the same plane, and the surface of a draw bead groove 201 on the bottom surface is continuously complete after being spliced. The top of each region blank holder block 12 is fixedly provided with a lower pressure rod 121 which movably penetrates through the upper die 2, the lower pressure rod 121 is fixedly connected to a hydraulic power output end at the top, and the vertical lifting of each region blank holder block 12 can be driven through the hydraulic power output end, so that blank holding forces with different magnitudes are provided at the edge of a plate material in the synchronous descending process with the lower die 2 (when the same hydraulic power output end is adopted, springs with different rigidities can be sleeved outside each lower pressure rod 121, so that the output of different acting forces under the same displacement condition can be realized). Preferably, the top of the upper die 2 is fixedly connected with a connecting base plate 9, so that the upper die 2 is convenient to fixedly mount. Meanwhile, a guide hole is formed in the connecting base plate 9, and the pressing rod 121 is movably sleeved in the guide hole so as to guide the vertical movement of the pressing rod 121.
Aiming at the defects of serious rebound, wrinkling, thinning and the like of the annular shell, the lattice conduction can be used for carrying out regional energization, changing current distribution and actively utilizing the non-uniformity to realize the uniform forming of the thin-wall asymmetric special-shaped structure.
The pushing block 10 is movably arranged at the top end of the inner part of the upper die 2, and when the pushing block 10 is completely positioned in the upper die 2, the bottom surface of the pushing block 10 and the surface of the stamping forming female die are smooth and excessive, so that the inner surface of the upper die 2 forms a complete forming surface. The pushing block 10 can be driven by electromagnetic force, is flexible and reliable, has quick response, can be completely positioned in the upper die 2 in an adsorption state, can not interfere with the stamping forming process, and particularly can not generate additional acting force except normal supporting force on the surface of a stamping part; after the stamping forming is completed, the pushing block 10 moves downwards under the action of electromagnetic force, so that the workpiece is separated from the stamping forming cavity, and the workpiece is conveniently demoulded.
As shown in fig. 11, a dot matrix voltage-conducting edge forming process of electric auxiliary forming includes the following steps:
(1) And (3) process parameter setting: setting parameters of the output force of a pulse power generator and each power output end according to the forming technological parameters of the plate to be formed; the molding process parameters mainly include the output power and duration of the pulse power generator providing the electric auxiliary heating, the back pressure value provided to the insulating blank holder 4, the molding pressure value provided to the upper die 2, and the trimming force value provided to each region trimming block 12.
(2) And (3) clamping the plate: lifting the fixing plates 5 on two sides, accurately placing the plate to be punched on the top surface of the insulating pressing plate 4, and then descending the fixing plates 5 on two sides, so that the fixing plates 5 press the edges of the plate below the fixing plates, and the bottom surfaces of the fixing plates 5 are reliably contacted with the edges of the plate, thereby ensuring that the current flowing into the fixing plates 5 can smoothly enter the plate;
(3) Current distribution setting: according to the optimal technological parameters obtained by the simulation forming of the plate material, the number and the position distribution of screw type electrodes 7 which are contacted with the fixed plate 5 on the electrode plate 6 are regulated; when a pulse power supply generator is used for supplying a preset pulse current to the electrode plates 6, a current path is formed between the two electrode plates 6, the current passes through the plate material to realize rapid auxiliary heating on the plate material, local high heat can be generated in the area corresponding to the position where the plate material is connected with the screw type electrode 7 and the fixed plate 5, and the local softening condition of a forming area is realized, so that the forming load is reduced, and the problems of high forming force and difficult forming of the thin-wall asymmetric special-shaped structural member are solved.
(4) And (3) electrifying and heating: forming operation current with preset power and current magnitude is fed into the electrode plate 6 through the pulse power supply generator and is continued for a preset time period, so that the plate is heated to a preset forming temperature;
(5) Zoned edge pressing: the main power output of the hydraulic press drives the upper die 2 to descend, the upper die is matched with the insulating pressing plate 4 to clamp the plate, the hydraulic power output end at the top provides vertical downward blank pressing force for each region blank pressing block 12, and the hydraulic power output end at the bottom provides vertical upward back pressure for the insulating pressing plate 4; and the uniformity of the thin-wall asymmetric special-shaped structure is realized by adopting the non-uniformity of the blank holder force.
(6) And (3) stamping and forming: the main power output of the hydraulic press drives the upper die 2 to continue to move downwards, the stamping forming male die 3 is matched with the stamping forming female die to finish the forming processing of the arched curved surface main body of the workpiece, and meanwhile, the draw bead groove 201 on the bottom surface of the upper die 2 is matched with the draw bead protrusion 801 on the top surface of the blank holder 8 to finish the forming of the extension bead on the arc-shaped plane turning edge of the workpiece;
(7) Low Wen Baoya: after stamping is completed, a pulse power supply generator is used for supplying pressure maintaining operation current with preset power and current to the electrode plate, and the operation current is kept for a preset time period and pressure maintaining;
(8) Taking out the sample: the main power output of the hydraulic press drives the upper die 2 to ascend, the insulating pressing plate 4 and the upper die 2 ascend synchronously, the insulating pressing plate 4 ascends to the highest position of the cycle and resets, the punched workpiece is separated from the punch forming male die 3, the pushing block 10 works, and the workpiece is pushed out of the upper die 2, so that the workpiece can be taken out of the forming die.
Before clamping the plate, oil stain treatment and finishing treatment are carried out on the surfaces of the plate, the upper die 2, the lower die 1 and the stamping forming male die 3 so as to ensure the subsequent clamping effect, and after the plate is cut into a target shape, high-temperature-resistant lubricating conductive coating is sprayed on the surface of the plate so as to improve the conductivity of the plate.
In the embodiment, with the thin-wall asymmetric special-shaped structure shown in fig. 1, the workpiece is made of a titanium alloy plate (such as TC4 and pure titanium) with the thickness of 1mm, and is manufactured by adopting the stamping forming convex die and the forming process. The edge pressing plates 8 on both sides of the plate material are divided into 4 single sides respectively, and the number of the corresponding region edge pressing blocks 12 (the number of edge pressing regions) is set to 3 single sides respectively, as shown by the broken lines in fig. 5. Before blanking the sample plate, current-assisted self-resistance heating-time-sharing progressive drawing-electrothermal coupling stress relaxation full-flow collaborative simulation is carried out, a simulation diagram is shown in fig. 12, wherein (a) in fig. 12 shows that the right end electrode is all connected, the middle part is 50% connected, the left end part is 25% connected, the middle end electrode shown in (b) in fig. 12 is all connected, and the two end electrodes are connected by 20% respectivelyTo the effect of non-uniformity in temperature. Through simulation analysis, the total pressure edge of the six areas is preferably 20-40t, and the specific pressure distribution is as follows: the binding force of the A area is 5.5t, the binding force of the B area is 2.1t (preventing wrinkling), the binding force of the C area is 5t, the binding force of the A1 area is 3t, the binding force of the B1 area is 8.5 (the curved surface is large, cracking is prevented), and the binding force of the C1 area is 4.5t. The current frequency of the current is 500Hz and the current density is 40-50A/mm before the stamping forming 2 A, the duty ratio is 5%, and the temperature of the plate after being electrified is preferably 600-800 ℃. The stamping force adopted in the stamping process is preferably 260t, and after the stamping is finished, the pressure maintaining working current is changed into small current (10A/mm 2 ～20A/mm 2 Suitably), the pressure is maintained for 600-1200 s.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes or direct or indirect application in other related technical fields are included in the scope of the present invention.
Claims (4)
1. An electrically assisted forming process for forming a dot matrix voltage conducting edge is characterized by comprising the following steps of: the forming process is applied to an electrically assisted forming lattice conductive edge pressing die, and the die is applied to a hydraulic press with multiple power outputs, and comprises the following steps of:
(1) And (3) process parameter setting: setting parameters of the output force of a pulse power generator and each power output end according to the forming technological parameters of the plate to be formed;
(2) And (3) clamping the plate: lifting the fixing plates at two sides, accurately placing the plate to be punched on the top surface of the insulating pressing plate, and then descending the fixing plates at two sides to ensure that the fixing plates are reliably contacted with the edges of the plate;
(3) Current distribution setting: according to the optimal technological parameters obtained by the simulation forming of the plate, the number and position distribution of screw type electrodes on the electrode plate, which are contacted with the fixed plate, are regulated;
(4) And (3) electrifying and heating: forming operation current with preset power and current magnitude is fed into the electrode plate through the pulse power supply generator and is continued for a preset time period, so that the plate is heated to a preset forming temperature;
(5) Zoned edge pressing: the upper die descends and is matched with the insulating pressing plate to clamp the plate, the hydraulic power output end at the top provides vertical downward edge pressing force for the edge pressing blocks in each region, and the hydraulic power output end at the bottom provides vertical upward back pressing force for the insulating pressing plate;
(6) And (3) stamping and forming: the upper die continues to descend, and the stamping male die and the stamping female die are matched to finish the forming processing of the plate;
(7) Low Wen Baoya: after stamping is completed, a pulse power supply generator is used for supplying pressure maintaining operation current with preset power and current to the electrode plate, and the operation current is kept for a preset time period and pressure maintaining;
(8) Taking out the sample: and the insulating pressing plate and the upper die synchronously move upwards, the punched workpiece is separated from the punch forming male die, and then the workpiece is taken out of the upper die.
2. The electrically assisted dot matrix voltage-conducting edge forming process according to claim 1, wherein: before clamping the plate, oil stain treatment and finishing treatment are carried out on the surfaces of the plate, the upper die, the lower die, the stamping male die and the stamping female die so as to ensure the subsequent clamping effect, and after the plate is cut into a target shape, high-temperature-resistant lubricating conductive coating is sprayed on the surface of the plate.
3. The electrically assisted dot matrix voltage-conducting edge forming process according to claim 1, wherein: in the step (4), the process parameters of the forming operation current are as follows: the current frequency is 500Hz, and the current density is 40-50A/mm 2 The duty ratio is 5%, and the preset forming temperature is 600-800 ℃.
4. A lattice voltage-conducting side forming process according to claim 1 or 3, wherein: in the step (7), the technological parameters of the pressure maintaining operation current are as follows: current magnitude 10A/mm 2 ～20A/mm 2 The pressure maintaining time is 600-1200 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202410205927.2A CN117772880B (en) | 2024-02-26 | Dot matrix voltage-conducting edge forming process for electric auxiliary forming |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410205927.2A CN117772880B (en) | 2024-02-26 | Dot matrix voltage-conducting edge forming process for electric auxiliary forming |
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| CN117772880A true CN117772880A (en) | 2024-03-29 |
| CN117772880B CN117772880B (en) | 2024-05-14 |
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