CN103706691B - Electronic universal tester is utilized to carry out sheet metal bending forming method - Google Patents

Abstract

A metal plate bending forming method is carried out by using an electronic universal testing machine to solve the problem that the existing metal plate needs to be corrected due to serious springback after forming. Device: a positioning bolt is threaded in the positioning screw hole, the lower bending die is set in the through groove of the lower die, the side walls of both ends of the lower bending die corresponding to the circular arc through groove are symmetrically provided with sample positioning grooves, and the lower end of the bending upper die is set In the lower die through groove. Method: 1. Install the metal plate bending forming device on the electronic universal testing machine; 2. Process samples suitable for the size of the upper and lower dies; 3. Set the control program of the electronic testing machine: set the control program including the loading stage and displacement Holding stage; 4. Heating the bending upper die and bending lower die; 5. Place the formed sample on the sheet metal bending forming device in the furnace; 6. Use the electronic testing machine to load the sheet metal bending forming device; 7. Take out the test piece In this way, a sheet metal bending is completed. The invention is used for bending forming of sheet metal.

Description

Bending method of sheet metal using electronic universal testing machine

technical field

The invention relates to a metal plate bending forming method, in particular to a metal plate bending forming method using an electronic universal testing machine.

Background technique

Plate parts are widely used in the fields of aviation, aerospace, ships and automobiles, such as titanium alloy fins of aircraft, aluminum alloy siding, automobile steel plate coverings, etc., but these materials have low elastic modulus, and the formed parts have serious springback , which affects the forming accuracy of the workpiece and reduces the product quality. In order to obtain high-precision, high-quality plate parts, the traditional method is to carry out a large number of development tests on the parts under different forming process conditions on the press before the mass production of the parts, so as to obtain the best forming process, including The best thermoforming parameters (forming temperature, forming speed, etc.), thermal correction parameters (holding load, holding time, etc.), and the best cooling method (air cooling, furnace cooling, etc.). However, there are serious disadvantages in developing the same size parts directly on the press to obtain the best forming process: high production cost, long development cycle, and a lot of manpower and material resources will be wasted. In addition, if there is no reasonable positioning device in the mold when the sheet is formed, the parts will shift during the forming process, resulting in large deviations in the shape and size of the formed parts from the design requirements, resulting in product scrapping. There is an urgent need to propose a forming device and a forming method that can greatly reduce production costs, shorten the development cycle and reduce the scrap rate.

Contents of the invention

In order to solve the problems of high forming cost, long development cycle and severe springback after forming, the present invention provides a metal sheet bending forming method using an electronic universal testing machine.

Device: The metal plate bending forming device using an electronic universal testing machine includes a bending upper die, a bending lower die, a lower die base, an upper nut, a lower nut and two positioning bolts. The lower end of the lower die base is provided with a lower connecting bolt. The upper end of the seat is provided with a lower mold through groove, and positioning screw holes are symmetrically arranged on the side wall of the lower mold base corresponding to the lower mold through groove, and a positioning bolt is threaded in each positioning screw hole, and the bending lower mold is arranged in the lower mold through groove , the upper end surface of the lower bending die is provided with arc through grooves, and the side walls of both ends of the lower bending die corresponding to the arc through grooves are symmetrically provided with sample positioning grooves, and the upper end of the bending upper die is provided with upper connecting bolts, and the upper end of the bending upper die is provided with upper connecting bolts. The lower end of the curved upper die is provided with an arc surface, the upper nut is threaded with the upper connecting bolt, the lower nut is threaded with the lower connecting bolt, and the lower end of the bending upper die is arranged in the through groove of the lower die.

Method: The metal plate bending forming method is realized through the following steps by using an electronic universal testing machine:

Step 1. Install the metal sheet bending forming device: install the metal sheet bending forming device on the electronic universal testing machine, screw the upper connecting bolt into the upper pressing head, screw the lower connecting bolt into the lower pressing head, and place the lower bending die horizontally on the lower pressing head. On the lower mold channel of the mold base, control the beam to move upward slowly, and adjust the bending lower mold and the bending upper mold to align and contact, adjust the contact force to 1000N, and screw the positioning bolts respectively from the positioning screw holes on the side wall of the lower mold base to The lower bending die is fixed, the upper nut is tightened toward the end face of the upper die to fasten the upper die to the upper die, the lower nut is tightened toward the end face of the lower die to fasten the lower die holder to the lower die, and the crossbeam is controlled to make the upper die bend Separate a distance from the bending die;

Step 2. Prepare the forming sample: select the titanium alloy sheet as the forming blank, and process a sample suitable for the size of the upper mold and the lower mold;

Step 3. Set the control program of the electronic testing machine: set the control program including the loading phase and the displacement holding phase:

a. The speed of the crossbeam in the loading stage is set at 5mm/min～15mm/min, and the loading ends after the set loading force reaches 3500N;

b. In the displacement maintenance stage, set the duration of the correction to 10min to 20min, keep the loading force constant at 500N, and set the data acquisition frequency to 200ms;

Step 4. Heating the bending upper mold and bending lower mold: move the middle section of the resistance furnace of the three-stage split resistance furnace to the metal plate bending forming device, close the furnace door, and set the temperature of the three-stage split resistance furnace to 600 ℃～800℃, using a three-stage split resistance furnace to heat the bending upper mold and bending lower mold;

Step 5. The formed sample is placed on the metal plate bending forming device in the furnace: after the temperature in the three-stage split resistance furnace reaches the set temperature, open the furnace door of the three-stage split resistance furnace and place the titanium alloy sheet , put it in the sample positioning groove, quickly close the furnace door, reset the load to zero on the computer program control interface, and manually control the beam to rise slowly to drive the lower bending die upward until the surface of the sample is in contact with the lower bending die , based on the observation that the load of the load sensor has increased, the displacement of the crossbeam is reset to zero through the displacement sensor, and the heat preservation is continued for 5 minutes;

Step 6. Use the electronic testing machine to load the sheet metal bending forming device: after the holding time is up, start the set control program and load the sheet metal bending forming device;

Step 7. Take out the sample: After forming, open the furnace door of the three-stage split resistance furnace, manually control the beam to move down and unload, quickly take out the sample and air-cool, cool for 10 minutes, and then complete the bending and forming of a metal sheet.

Compared with the traditional plate bending technology, the present invention has the following beneficial effects:

1. The sample positioning groove in the device of the present invention can realize fast and accurate positioning of the sheet metal, and the designed lower mold base can ensure the fast assembly and alignment of the bending upper mold and the bending lower mold, and the lower mold base can be used when forming different parts , so as to reduce the production cost and development cycle of sheet metal forming, and quickly determine the best forming process of sheet metal.

2. The present invention uses positioning bolts to adjust the left and right positions of the lower bending die, so that the axes of the lower bending die and the upper bending die can be quickly centered, saving a lot of adjustment time for the centering of the device axes.

3. Utilizing the process parameters in the method of the present invention to carry out loading and forming on the metal plate, the workpiece after forming has small rebound, and realizes the precision forming of the plate parts.

Description of drawings

Fig. 1 is a front view of the entire structure of the present invention; Fig. 2 is a front view of the lower die base 3; Fig. 3 is a left view of Fig. 2; Fig. 4 is a top view of Fig. 2, and Fig. 5 is a front view of a curved upper die 1; Fig. 6 is a left view of Fig. 5; Fig. 7 is a front view of the lower bending die 2; Fig. 8 is a left view of Fig. 7; Fig. 9 is a top view of Fig. 7; Fig. 10 is a structural front view of the third embodiment.

Detailed ways

Specific embodiment 1: This embodiment is described in conjunction with Fig. 1 to Fig. 9. This embodiment includes a bending upper mold 1, a bending lower mold 2, a lower mold base 3, an upper nut 4, a lower nut 5 and two positioning bolts 6, the lower The lower end of the mold base 3 is provided with a lower connecting bolt 3-1, the upper end of the lower mold base 3 is provided with a lower mold through groove 3-2, and the lower mold base 3 side wall corresponding to the lower mold through groove 3-2 is symmetrically provided with positioning Screw holes 3-3, each positioning screw hole 3-3 is threaded to connect a positioning bolt 6, the bending lower die 2 is arranged in the lower die through groove 3-2, and the upper end surface of the bending lower die 2 is provided with an arc through groove 2 -1, the arc groove 2-1 is symmetrically provided with sample positioning grooves 2-2 on the side walls at both ends of the bending lower die 2, the sample positioning grooves 2-2 are used to support the workpiece, and the upper end of the bending upper die 1 There is an upper connecting bolt 1-1, the lower end of the curved upper die 1 is provided with an arc surface 1-2, the upper nut 4 is threaded with the upper connecting bolt 1-1, the lower nut 5 is threaded with the lower connecting bolt 3-1, The lower end of the bending upper die 1 is arranged in the lower die through groove 3-2.

Specific Embodiment 2: This embodiment is described in conjunction with FIG. 1 . The bending upper die 1, bending lower die 2, lower die holder 3, upper nut 4, lower nut 5 and two positioning bolts 6 of this embodiment are all 4Cr5MoSiV. This material is resistant to high temperatures and can be used below 900°C. Other components and connections are the same as those in the first embodiment.

Specific embodiment three: This embodiment is described in conjunction with FIG. 10. This embodiment is a method for realizing variable cross-section extrusion and twisting of metal materials using the device of specific embodiment one. The steps are as follows:

Step 1. Install the sheet metal bending forming device: install the sheet metal bending forming device on the electronic universal testing machine, screw the upper connecting bolt 1-1 into the upper pressing head 7, and screw the lower connecting bolt 3-1 into the lower pressing head 8 , place the bending lower die 2 horizontally on the lower die channel 3-2 of the lower die holder 3, control the beam 9 to move upward slowly, and adjust the bending lower die 2 to be in positive contact with the bending upper die 1, and adjust the contact force to 1000N, respectively Screw in the positioning bolt 6 from the positioning screw hole on the side wall of the lower mold base 3 to fix the curved lower mold 2, tighten the upper nut 4 towards the end face of the upper pressing head to fasten the bending upper mold 1 to the upper pressing head 7, and press down Tighten the lower nut 5 on the end face of the head to fasten the lower mold base 3 to the lower pressing head 8, and control the crossbeam 9 to separate the bending upper mold 1 from the bending lower mold 2 by a certain distance, which is enough for the convenience of placing the test piece;

Step 2. Prepare the forming sample: select the titanium alloy sheet as the forming blank, and process a sample suitable for the size of the upper mold and the lower mold;

Step 3. Set the control program of the electronic testing machine: set the control program including the loading phase and the displacement holding phase:

a. The speed of beam 9 is set at 5 mm/min to 15 mm/min during the loading stage, and the loading ends after the set loading force reaches 3500 N;

b. In the displacement maintenance stage, set the duration of the correction to 10min to 20min, keep the loading force constant at 500N, and set the data acquisition frequency to 200ms;

Step 4. Heating the upper bending die 1 and the lower bending die 2: move the middle section of the resistance furnace of the three-stage split resistance furnace 10 to the metal plate bending forming device, close the furnace door, and set the three-stage split resistance furnace 10 The temperature is 600°C to 800°C, and the bending upper mold 1 and the bending lower mold 2 are heated by using a three-stage split resistance furnace 10;

Step 5. The formed sample is placed on the metal plate bending forming device in the furnace: after the temperature in the three-stage split resistance furnace 10 reaches the set temperature, open the furnace door of the three-stage split resistance furnace 10, and place the titanium alloy Place the sheet material in the sample positioning groove 2-2, quickly close the furnace door, reset the load to zero on the computer program control interface, manually control the beam 9 to rise slowly to drive the bending lower die 2 to move up until the test The surface of the sample is in contact with the lower bending die 2, subject to the observation that the load of the load sensor 11 increases, the displacement of the crossbeam 9 is reset by the displacement sensor 12, and the displacement of the crossbeam 9 is reset to zero, and the temperature of the sample is uniformed by continuing to keep warm for 5 minutes;

Step 6. Use the electronic testing machine to load the sheet metal bending forming device: after the holding time is up, start the set control program and load the sheet metal bending forming device;

Step 7. Take out the sample: After forming, open the furnace door of the three-stage split resistance furnace 10, manually control the beam 9 to move down and unload, quickly take out the sample and air-cool it for 10 minutes, and then complete the bending and forming of a metal sheet.

Embodiment 4: This embodiment is described with reference to FIG. 10 . In this embodiment, the speed of the crossbeam 9 in the loading stage in step 3 is set to 9 mm/min. Other steps are the same as in the third embodiment.

Embodiment 5: This embodiment is described with reference to FIG. 10 . In this embodiment, the speed of the crossbeam 9 in the loading stage in step 3 is set to 12 mm/min. Other steps are the same as in the third embodiment.

Embodiment 6: This embodiment is described with reference to FIG. 10 . In this embodiment, the duration of the shape correction is set to 15 minutes in the displacement maintenance stage in step 3. Other steps are the same as those in Embodiment 3, 4 or 5.

Embodiment 7: This embodiment is described with reference to FIG. 10 . In this embodiment, the duration of the shape correction is set to 18 minutes in the displacement maintenance stage in step 3. Other steps are the same as those in Embodiment 3, 4 or 5.

Embodiment 8: This embodiment is described with reference to FIG. 10 . In this embodiment, the temperature of the three-stage split resistance furnace 10 is set at 650° C. in step 4. Other steps are the same as in the third embodiment.

Ninth specific embodiment: This embodiment is described with reference to FIG. 10 . In this embodiment, the temperature of the three-stage split resistance furnace 10 is set at 700° C. in step four. Other steps are the same as in the third embodiment.

Embodiment 10: This embodiment is described with reference to FIG. 10 . In this embodiment, the temperature of the three-stage split resistance furnace 10 is set to 750° C. in step 4. Other steps are the same as in the third embodiment.

Claims (8)

1. utilize electronic universal tester to carry out a sheet metal bending forming method, it is characterized in that: described method is realized by following steps:

Step one, sheet metal pane bending apparatus is installed: be arranged on electronic universal tester by sheet metal pane bending apparatus, upper connecting bolt (1-1) screws in seaming chuck (7), lower connecting bolt (3-1) screws in push-down head (8), to bend counterdie (2) lies in a horizontal plane on the counterdie groove (3-2) of die shoe (3), control crossbeam (9) slowly up, and regulate bending counterdie (2) to align with bending patrix (1) to contact, adjustment contact force is 1000N, bolt (6) is screwed in respectively from the positioning screw hole of die shoe (3) sidewall, bending counterdie (2) is fixed, tighten top nut (4) towards seaming chuck end face will bend patrix (1) and be fastened to seaming chuck (7), tighten lower nut (5) towards push-down head end face and die shoe (3) is fastened to push-down head (8), controlling crossbeam (9) makes bending patrix (1) separate a segment distance with bending counterdie (2),

Step 2, preparation shaping sample: selected titanium alloy plate as forming blank, and processes the sample of applicable upper die and lower die size;

Step 3, the control program of electronic test machine is set: control program is set and comprises two stages: load phase and displacement keep the stage,

The Speed Setting of a, load phase crossbeam (9) is 5mm/min ~ 15mm/min, and setting loading force loads after reaching 3500N and terminates;

B, displacement keep the phase sets school shape duration to be 10min ~ 20min, and loading force keeps 500N constant, and data acquiring frequency is set as 200ms;

Step 4, to bending patrix (1) and bending counterdie (2) heating: the resistance burner hearth stage casing that mobile syllogic splits resistance furnace (10) is positioned at sheet metal pane bending apparatus place, closed fire door, the temperature that setting syllogic splits resistance furnace (10) is 600 DEG C ~ 800 DEG C, utilizes syllogic to split resistance furnace (10) to bending patrix (1) and bending counterdie (2) heating;

Step 5, shaping sample is placed in the sheet metal pane bending apparatus in stove: syllogic is split after resistance furnace (10) interior temperature reaches design temperature, open the fire door that syllogic splits resistance furnace (10), place titanium alloy plate, it is made to be placed in sample locating slot (2-2), rapid closedown fire door, reset load at the program interface screen of computer to reset, Non-follow control crossbeam (9) slowly rises and moves to drive on bending counterdie (2), until specimen surface contacts with bending counterdie (2), load increase is had to be as the criterion to observe load transducer (11), reset crossbeam (9) displacement by displacement transducer (12) to reset, continue insulation 5min,

Step 6, electronic test machine is utilized to load sheet metal pane bending apparatus: the control program that temperature retention time sets to rear startup also loads sheet metal pane bending apparatus;

Step 7, taking-up sample: be shaped after terminating, open the fire door that syllogic splits resistance furnace (10), Non-follow control crossbeam (9) moves down unloading, takes out sample air cooling rapidly, cooling 10min, namely completes a sheet metal bending forming;

Described step, four, five, sheet metal pane bending apparatus in six comprises bending patrix (1), bending counterdie (2), die shoe (3), top nut (4), lower nut (5) and two bolts (6), the lower end of die shoe (3) is provided with lower connecting bolt (3-1), the upper end of die shoe (3) is provided with counterdie groove (3-2), die shoe (3) sidewall that counterdie groove (3-2) is corresponding is arranged with positioning screw hole (3-3), be threaded in each positioning screw hole (3-3) bolt (6), bending counterdie (2) is arranged in counterdie groove (3-2), the upper surface of bending counterdie (2) is provided with circular arc groove (2-1), bending counterdie (2) the two ends sidewall that circular arc groove (2-1) is corresponding is arranged with sample locating slot (2-2), the upper end of bending patrix (1) is provided with connecting bolt (1-1), the lower end of bending patrix (1) is provided with arc surface (1-2), top nut (4) is threaded with upper connecting bolt (1-1), lower nut (5) is threaded with lower connecting bolt (3-1), the lower end of bending patrix (1) is arranged in counterdie groove (3-2).

2. utilize electronic universal tester to carry out sheet metal bending forming method according to claim 1, it is characterized in that: in described step 3, the Speed Setting of load phase crossbeam (9) is 9mm/min.

3. utilize electronic universal tester to carry out sheet metal bending forming method according to claim 1, it is characterized in that: in described step 3, the Speed Setting of load phase crossbeam (9) is 12mm/min.

4. according to claim 1,2 or 3, utilize electronic universal tester to carry out sheet metal bending forming method, it is characterized in that: in described step 3, displacement keeps the phase sets school shape duration to be 15min.

5. according to claim 1,2 or 3, utilize electronic universal tester to carry out sheet metal bending forming method, it is characterized in that: in described step 3, displacement keeps the phase sets school shape duration to be 18min.

6. utilize electronic universal tester to carry out sheet metal bending forming method according to claim 1, it is characterized in that: setting the temperature that syllogic splits resistance furnace (10) in described step 4 is 650 DEG C.

7. utilize electronic universal tester to carry out sheet metal bending forming method according to claim 1, it is characterized in that: setting the temperature that syllogic splits resistance furnace (10) in described step 4 is 700 DEG C.

8. utilize electronic universal tester to carry out sheet metal bending forming method according to claim 1, it is characterized in that: setting the temperature that syllogic splits resistance furnace (10) in described step 4 is 750 DEG C.