Variable height semi-cylindrical rust-proof aluminum part forming tool and use method thereof

Abstract

The present invention belongs to the technical field of aluminum alloy sheet metal processing for aviation aircraft, and specifically relates to a variable-height semi-cylindrical anti-rust aluminum part forming tool and a method of using the tool, including a drawing die and a matching mold. By using a brand-new barrel-shaped anti-rust aluminum part drawing and forming tool, two parts can be processed at one time. By symmetrically placing the parts on the tool, the drawing and forming process effectively offsets the deformation caused by the processing process, avoids the breakage of the sheet material, and increases the mold fit of the formed parts to no more than 0.5 mm, thereby reducing the amount of workers' trimming and improving product quality.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy sheet metal processing for aviation aircraft, and specifically relates to a variable-height semi-cylindrical rust-proof aluminum part forming tool and a use method thereof, which are used for aluminum alloy deep drawing forming. Background Art

[0002] Aircraft support parts are usually composed of two semi-cylindrical rust-proof aluminum parts. Such barrel-shaped parts are traditionally processed by drop forming. Due to the low elongation and poor plasticity of rust-proof aluminum materials, and the semi-circular shape of the barrel-shaped parts themselves, the parts are wrinkled and cracked during the drop forming process due to the rapid application of pressure and insufficient extension of the parts. In addition, the surface quality and processing accuracy of the parts after drop forming are unstable, and the parts are easily scrapped, and the workers have a large workload for later repair. In addition, when assembling the parts, the two semi-cylindrical rust-proof aluminum parts that are symmetrical on both sides need to be welded to form a cylindrical structure, in which the finished parts used by the aircraft are installed. The finished parts are spherical, and the diameter of the sphere is 2mm different from the diameter of the circular opening after welding. When installing, the finished parts are placed in the circular opening after welding to ensure that the gap with the circular opening of the barrel-shaped structural part is uniform. Therefore, the processing accuracy of the barrel surface is also required to be high, and the processing accuracy of each semi-cylindrical barrel part is required to be no more than 0.5mm. Therefore, it is urgent to adopt new processing methods to improve the processing accuracy and processing efficiency of the products. Summary of the invention

[0003] The purpose of the present invention is to invent a processing tool and manufacturing method for a variable height semi-cylindrical rust-proof aluminum part, which can realize high-quality processing of two barrel-shaped rust-proof aluminum parts of different heights at the same time, and the parts will not be cracked or have surface defects such as wrinkles after forming. In order to achieve the above purpose, the technical solution of the present invention is as follows:

[0004] A new set of barrel-shaped anti-rust aluminum parts deep drawing tooling and process flow was designed. By using a hydraulic press to connect the upper die and the lower die, qualified parts were processed using a combination of "punch" and "die".

[0005] A variable height semi-cylindrical rust-proof aluminum part forming tool, comprising a drawing die and a matching die;

[0006] The drawing die comprises a lower die plate 1, a discharge screw 2, a spring 3, a cylindrical pin 4, a die 5, a guide sleeve 6, a guide column 7, a blank holder cylindrical pin 8, a blank holder 9, an upper die plate 10, a guide column seat 11, a screw 12, a punch 13, a lifting ring 14, a U-shaped connecting groove 15 and a symmetry axis punching point 16;

[0007] The lower template 1 is the bottom surface of the tooling, and a discharge screw 2 is installed on the lower template 1, and a spring 3 is installed on the discharge screw 2. When the mold is closed, the end of the discharge screw 2 presses against the surface of the part, which is used to bounce the formed part when a reverse force is applied; a cylindrical pin 4 is installed on the upper surface of the lower template 1, which is used to be fixedly connected with the lower surface of the die 5; the shape of the die 5 is consistent with the shape of the part; a guide sleeve 6 is installed around the lower template 1, and a guide column 7 is installed inside the guide sleeve 6. The guide column 7 is connected to the guide column seat 11 on the upper template 10, which is used to guide the upper template 10 and the lower template 1 during the part processing process;

[0008] A blank holder cylindrical pin 8 is installed around the upper surface of the die 5; the upper end of the blank holder cylindrical pin 8 is connected to a blank holder 9, which is used to hold the part to be processed, so as to facilitate the subsequent punch 13 to perform stamping and drawing; the upper surface of the punch 13 is connected to the upper template 10 by a screw 12, and two symmetrical axis punching points 16 are arranged on the axis of the punch 13, which are used to make two punching points on the part during the stamping and drawing process, so as to facilitate alignment and positioning with the punching point positioning holes 18; lifting rings 14 are installed on both sides of the upper template 10 for lifting by a crane, and a U-shaped connecting groove 15 is arranged on the edge of the upper template 10 without the lifting ring 14, and the function of the U-shaped connecting groove 15 is to fix the upper template 10 with the hydraulic press working platform by using a bolt rod; a U-shaped connecting groove 15 is also arranged on the edge of the lower template 1;

[0009] The matching mold comprises a matching mold body 17, the shape of which is consistent with the theoretical shape of the part, which is convenient for finishing the part after deep drawing. Two punching point positioning holes 18 are arranged on the matching mold body 17 for positioning the part at the punching points made in the previous process.

[0010] The method for using the variable height semi-cylindrical rust-proof aluminum part forming tool comprises the following steps:

[0011] The first step is to use a crane to lift the lower template 1 to the center of the hydraulic press working platform, and use bolts to tighten it on the working platform through the U-shaped connecting groove 15 on the lower template 1 to ensure that it does not move during the hydraulic press deep drawing process; then install the unloading screw 2 on the lower template 1 and put on the spring 3 to ensure that the verticality is not greater than 1 degree;

[0012] The second step is to insert the die 5 into the cylindrical pin 4 for positioning and installation, and process the sheet material to be processed into a circle to ensure that two parts can be formed by deep drawing at one time; the processed sheet material is placed on the die 5, and the sheet material diameter is ensured to be 20-30mm larger than the maximum profile of the die 5. The excess sheet material is used for the blank holder 9 to apply pressure to fix the part rough material;

[0013] The third step is to use bolts to connect the upper template 10 with the upper workbench of the hydraulic press through the U-shaped connecting groove 15 on the upper template 10. After the connection is completed, the hydraulic press is started to move the punch 13 downward to test the mold to ensure that the punch 13 can be smoothly closed with the die 5 on the lower workbench; according to the closing height of the drawing die and the slider stroke of the selected equipment, decide whether to add shims on the equipment workbench; if shims need to be added, according to the outer dimensions of the drawing die, the shims are evenly placed on the equipment workbench every 200 to 300 mm to ensure left-right symmetry;

[0014] Step 4: After the mold test is qualified, insert the cylindrical pin 8 of the blank holder into the concave die 5, and then guide the blank holder 9 along the cylindrical pin 8 to connect with the concave die 5, press the sheet between the two, and the gap between the sheet and the upper and lower dies is not more than 3mm;

[0015] Step 5: Manually cut two test pressure blanks according to the size of the aluminum alloy sheet; place one test pressure blank on the blank holder 9 connected to the drawing die 5 to ensure uniform peripheral margin; set the hydraulic press pressure and the depth of the first deep drawing test; the slide moves downward, the mold closes, and after the pressure is maintained for more than 5 seconds, the slide moves upward and the mold opens; use the reaction force of the spring 3 on the unloading screw 2 to make the test pressure blank fall out of the die 5; after the parts are taken out, observe the deep drawing forming of the parts to see if there are wrinkles or cracks;

[0016] Step 6: Adjust the deep drawing test conditions: According to the material flow of the test parts, manually trim the raw materials that have not been deep drawn, and appropriately remove the parts where the material flow is not smooth; if wrinkles appear, increase the blank holder force; if cracks appear, reduce the blank holder force or apply lubricating oil on the die 5 and the blank holder ring 9; for parts that are not cracked, manually smooth the wrinkles, increase the drawing depth and continue the deep drawing test;

[0017] Broken parts need to be replaced, and the test material is re-cut according to the trimmed raw material and then tested; through multiple tests, the drawing depth is gradually increased until the final forming state of the drawing die is reached, and the forming depth and blank holding force are recorded each time to determine the size and shape of the drawn sheet;

[0018] Step 7: Shear or mill the drawn sheet according to the sheet size and shape determined by the pressure test; perform deep drawing according to the forming process determined during the deep drawing test: When the hydraulic press performs deep drawing, the deep drawing is performed in steps according to the pressure test record. All parts are drawn at the same depth, and the wrinkles are manually smoothed after being taken out, and then the next depth value is pressed until the final deep drawing state of the drawing die is reached;

[0019] The eighth step is to place the drawn sheet material on the matching mold body 17, and position it according to the punch point 16 of the symmetry axis on the punch 13 on the punch point left on the part to ensure that the punch point on the sheet material is aligned with the punch point positioning hole 18 and connect the two punch points. Subsequently, the circular drawn part is sheared by marking to produce two symmetrical parts, completing the final part processing.

[0020] Beneficial effects of the present invention:

[0021] By using the new barrel-shaped rust-proof aluminum parts deep drawing and forming tooling, two parts can be processed at one time. By symmetrically placing them on the tooling, the deep drawing and forming process effectively offsets the deformation caused by the processing process, avoids the breakage of the sheet metal, and increases the mold fit of the formed parts to no more than 0.5mm, reducing the amount of workers' trimming and improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Side view of the drawing die

[0023] Figure 2 Top view of the punch of the drawing die

[0024] Figure 3 Schematic diagram of the drawing die after assembly

[0025] Figure 4 Top view of the matching mold

[0026] Figure 5 Positioning view of the part on the matching mold

[0027] In the figure: lower template 1, unloading screw 2, spring 3, cylindrical pin 4, concave die 5, guide sleeve 6, guide column 7, blank holder cylindrical pin 8, blank holder 9, upper template 10, guide column seat 11, screw 12, punch 13, lifting ring 14, U-shaped connecting groove 15, symmetry axis punching point 16, matching mold tire body 17, punching point positioning hole 18 DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with specific embodiments.

[0029] A tooling for deep drawing and forming of semi-cylindrical rust-proof aluminum parts with variable height, characterized in that the manufacturing method mainly consists of deep drawing and matching finishing, the tooling used for deep drawing of parts is "including drawing die", and the tooling used for matching finishing is called "matching die";

[0030] The drawing die comprises a lower die plate 1, a discharge screw 2, a spring 3, a cylindrical pin 4, a die 5, a guide sleeve 6, a guide column 7, a blank holder cylindrical pin 8, a blank holder 9, an upper die plate 10, a guide column seat 11, a screw 12, a punch 13, a lifting ring 14, a U-shaped connecting groove 15 and a symmetry axis punching point 16;

[0031] The lower template 1 is the bottom surface of the tooling, and the thickness can be controlled between 30-50mm. A certain number of unloading screws 2 are installed on the lower template 1, and springs 3 are installed on the unloading screws 2 to bounce the formed parts when a reverse force is applied; four cylindrical pins 4 are installed on the upper surface of the lower template 1 for fixed connection with the lower surface of the die 5; the shape of the die 5 is consistent with the shape of the part, and CNC machining can be used; a certain number of guide sleeves 6 are installed around the lower template 1, and guide pillars 7 are installed inside the guide sleeves 6. The guide pillars 7 are docked with the guide pillar seats 11 on the upper template 10, and are used for guiding the upper template 10 and the lower template 1 during the part processing process;

[0032] A blank holder cylindrical pin 8 is installed around the upper surface of the die 5, and the height of the blank holder cylindrical pin 8 can be 10-15mm; the upper end of the blank holder cylindrical pin 8 is connected to a blank holder 9, and the blank holder 9 is used to press the part to be processed, so as to facilitate the subsequent punch 13 to perform stamping and drawing; the upper surface of the punch 13 is connected to the upper template 10 by a screw 12, and two symmetry axis punching points 16 are arranged on the axis of the punch 13, which are used to make two punching points on the part during the stamping and drawing process, so as to facilitate the positioning of the next step; lifting rings 14 are installed on both sides of the upper template 10 for lifting by a crane, and a certain number of U-shaped connecting grooves 15 are provided on the edge where the lifting ring 14 is not installed, and the function of the U-shaped connecting groove 15 here is to fix the upper template 10 with the hydraulic press working platform by using bolt rods;

[0033] The matching mold is a matching mold body 17, which needs to be processed by a five-axis CNC machine tool. The shape of the matching mold body 17 is consistent with the theoretical shape of the part, which is convenient for finishing after the part is deep-drawn. Two punching point positioning holes 18 are provided on the matching mold body 17 for positioning the part at the punching points made in the previous process.

[0034] This tooling design structure and manufacturing method can gradually extend the rust-proof aluminum sheet through the slow drawing movement of the hydraulic press, and finally achieve a barrel-shaped structure.

[0035] The first step is to use a crane to lift the lower template 1 to the center of the hydraulic press working platform, and use bolts to tighten it on the working platform through the U-shaped connection groove 15 on the lower template 1 to ensure that it does not move during the hydraulic press deep drawing process. Then install the unloading screw 2 on the lower template 1 and put on the spring 3 to ensure that the verticality is not greater than 1 degree.

[0036] The second step is to insert the die 5 into the cylindrical pin 4 for positioning and installation, and process the rust-proof aluminum alloy sheet to be processed into a circle to ensure that two parts can be formed by deep drawing at one time. The processed sheet is placed on the die 5, and the sheet diameter is ensured to be 20-30mm larger than the maximum profile of the die 5. The excess sheet is used for the blank holder 9 to apply pressure to fix the part rough material.

[0037] The third step is to use bolts to connect the upper template 10 to the upper workbench of the hydraulic press through the U-shaped connection groove 15. After the connection is completed, start the hydraulic press to move the punch 13 downward to test the die to ensure that the punch 13 can be smoothly closed with the die 5 on the lower workbench. According to the closing height of the drawing die and the slider stroke of the selected equipment, decide whether to add shims on the equipment workbench. If shims need to be added, place the shims evenly on the equipment workbench every 200 to 300 mm according to the outer dimensions of the drawing die to ensure left-right symmetry.

[0038] After the fourth step of the mold trial is qualified, the cylindrical pin 8 of the pressure ring is inserted into the die 5, and then the pressure ring 9 is guided along the cylindrical pin 8 to connect with the die 5, and the rust-proof aluminum sheet is pressed between the two. The gap between the sheet and the upper and lower molds is not more than 3mm.

[0039] Step 5. Manually cut two test pressure materials according to the size of aluminum alloy sheet. Place a test pressure raw material on the blank holder 9 connected to the drawing die 5 to ensure uniform peripheral margin. Set the hydraulic press pressure and the depth of the first deep drawing test. The slider moves downward, the mold closes, and after the pressure is maintained for more than 5 seconds, the slider moves upward and the mold opens. Use the reaction force of the spring 3 on the unloading screw 2 to make the test pressure part fall out of the die 5. After the part is taken out, observe the deep drawing forming of the part to see if there are wrinkles or cracks.

[0040] Step 6: Adjust the deep drawing test conditions: According to the material flow of the test parts, manually trim the raw materials that have not been deep drawn, and appropriately remove the parts where the material flow is not smooth; if wrinkles appear, increase the blank holder force; if cracks appear, reduce the blank holder force or apply lubricating oil on the die 5 and the blank holder ring 9. For parts that are not cracked, after manually smoothing the wrinkles, increase the drawing depth and continue the deep drawing test;

[0041] Broken parts need to be replaced, and the test material is re-cut according to the trimmed raw material and then tested. Through multiple tests, the drawing depth is gradually increased until the final forming state of the drawing die is reached, and the forming depth and blank holding force are recorded each time to determine the size and shape of the drawn sheet.

[0042] The seventh step is to shear or mill the deep-drawn sheet according to the sheet size and shape determined by the pressure test. Deep drawing is carried out according to the forming process determined during the deep drawing test: When the hydraulic press is deep drawing, the deep drawing is carried out in steps according to the pressure test record. All parts are drawn at the same depth, and the wrinkles are manually smoothed after being taken out, and then the next depth value is pressed until the final deep drawing state of the deep drawing die is reached.

[0043] The eighth step is to place the drawn part sheet on the matching mold body 17, and position it according to the punch point 16 of the symmetry axis on the punch 13 at the punch point left on the part, ensure that the punch point on the sheet is aligned with the punch point positioning hole 18 and connect the two punch points, and then cut the circular drawn part by marking to produce two symmetrical parts, completing the final part processing.

Claims

1. A method for using a variable height semi-cylindrical rust-proof aluminum part forming tool, characterized in that: The method of use is realized based on a variable height semi-cylindrical rust-proof aluminum part forming tooling, including a drawing die and a matching die; The drawing die comprises a lower die plate (1), a discharge screw (2), a spring (3), a cylindrical pin (4), a die (5), a guide sleeve (6), a guide column (7), a blank holder cylindrical pin (8), a blank holder (9), an upper die plate (10), a guide column seat (11), a screw (12), a punch (13), a lifting ring (14), a U-shaped connecting groove (15) and a symmetry axis punch point (16); The lower template (1) is the bottom surface of the tooling. A discharge screw (2) is installed on the lower template (1). A spring (3) is installed on the discharge screw (2). When the mold is closed, the end of the discharge screw (2) presses against the surface of the part, which is used to bounce the formed part when a reverse force is applied. A cylindrical pin (4) is installed on the upper surface of the lower template (1) for fixed connection with the lower surface of the die (5). The shape of the die (5) is consistent with the shape of the part. A guide sleeve (6) is installed around the lower template (1). A guide column (7) is installed inside the guide sleeve (6). The guide column (7) is docked with a guide column seat (11) on the upper template (10) and is used to guide the upper template (10) and the lower template (1) during the part processing process. A blank holder cylindrical pin (8) is installed around the upper surface of the concave die (5); the upper end of the blank holder cylindrical pin (8) is connected to the blank holder (9), and the blank holder (9) is used to hold down the part to be processed, so as to facilitate the subsequent punch (13) to perform stamping and drawing; the upper surface of the punch (13) is connected to the upper template (10) by screws (12), and two symmetrical axis punching points (16) are arranged on the axis of the punch (13), which are used to make two punching points on the part during the stamping and drawing process, so as to facilitate alignment and positioning with the punching point positioning holes (18); lifting rings (14) are installed on both sides of the upper template (10) for lifting by a crane, and a U-shaped connecting groove (15) is arranged on the edge of the upper template (10) without the lifting ring (14), and the function of the U-shaped connecting groove (15) is to fix the upper template (10) with the hydraulic press working platform by using a bolt rod; the edge of the lower template (1) is also provided with a U-shaped connecting groove (15); The matching mold comprises a matching mold body (17), the shape of the matching mold body (17) is consistent with the theoretical shape of the part, which is convenient for finishing the part after deep drawing. The matching mold body (17) is provided with two punching point positioning holes (18) for positioning the part at the punching points made in the previous process. The method of use comprises the following steps: The first step is to use a crane to lift the lower template (1) to the center of the hydraulic press working platform, and use bolts to tighten it to the working platform through the U-shaped connection groove (15) on the lower template (1) to ensure that it does not move during the hydraulic press deep drawing process; then install the unloading screw (2) on the lower template (1) and put on the spring (3) to ensure that the verticality is not greater than 1 degree; The second step is to insert the die (5) into the cylindrical pin (4) for positioning and installation, and process the sheet material to be processed into a circle to ensure that two parts can be formed by deep drawing at one time; the processed sheet material is placed on the die (5) to ensure that the sheet material diameter is 20-30 mm larger than the maximum profile of the die (5), and the excess sheet material is used for the blank holder (9) to apply pressure to fix the part rough material; The third step is to use bolts to connect the upper platen (10) to the upper workbench of the hydraulic press through the U-shaped connection groove (15). After the connection is completed, the hydraulic press is started to move the punch (13) downward to perform a die test to ensure that the punch (13) can be smoothly closed with the die (5) on the lower workbench. According to the closing height of the drawing die and the slide stroke of the selected equipment, it is decided whether to add shims on the equipment workbench. If shims are needed, the shims are evenly placed on the equipment workbench every 200 to 300 mm according to the outer dimensions of the drawing die to ensure left-right symmetry. Step 4: After the mold test is qualified, the blank holder cylindrical pin (8) is inserted into the concave mold (5), and then the blank holder (9) is guided along the blank holder cylindrical pin (8) to connect with the concave mold (5), and the sheet metal is pressed between the two. The gap between the sheet metal and the upper and lower molds is not more than 3 mm; Step 5: Manually cut two test pressure blanks according to the size of the aluminum alloy sheet; place one test pressure blank on the blank holder (9) connected to the drawing die (5) to ensure that the peripheral margin is uniform; set the hydraulic press pressure and the depth of the first deep drawing test; move the slide downward, close the die, and after holding the pressure for more than 5 seconds, move the slide upward and open the die; use the reaction force of the spring (3) on the unloading screw (2) to make the test pressure blank fall out of the die (5); after the part is taken out, observe the deep drawing forming condition of the part to see if there are wrinkles or cracks; Step 6: Adjust the deep drawing test conditions: According to the material flow of the test parts, manually trim the raw materials that have not been deep drawn, and appropriately remove the parts where the material flow is not smooth; if wrinkles appear, increase the blank holder force; if cracks appear, reduce the blank holder force or apply lubricating oil to the die (5) and the blank holder ring (9); for parts that are not cracked, manually smooth the wrinkles, increase the drawing depth and continue the deep drawing test; Broken parts need to be replaced, and the test material is re-cut according to the trimmed raw material and then tested; through multiple tests, the drawing depth is gradually increased until the final forming state of the drawing die is reached, and the forming depth and blank holding force are recorded each time to determine the size and shape of the drawn sheet; Step 7: Shear or mill the drawn sheet according to the sheet size and shape determined by the pressure test; perform deep drawing according to the forming process determined during the deep drawing test: When the hydraulic press performs deep drawing, the deep drawing is performed in steps according to the pressure test record. All parts are drawn at the same depth, and the wrinkles are manually smoothed after being taken out, and then the next depth value is pressed until the final deep drawing state of the drawing die is reached; In the eighth step, the drawn sheet is placed on the matching mold body (17), and the punch point (16) on the punch (13) is positioned on the punch point left on the part to ensure that the punch point on the sheet is aligned with the punch point positioning hole (18) and the two punch points are connected. Subsequently, the circular drawn part is sheared by marking to produce two symmetrical parts, completing the final part processing.

Images