High conical stainless steel oil drain base part forming method

Abstract

The invention belongs to the technical field of aviation aircraft sheet metal part machining, and relates to a high conical stainless steel oil drain base part forming method. After the multi-procedure forming tool is used for machining the part, precise manufacturing of the high-cone-shaped stainless steel part can be achieved, knocking and repairing marks caused by manual forming are reduced, and the surface quality and the machining efficiency of the part are improved. Meanwhile, after the narrow long groove in the inner surface of the part is machined in an electric spark mode, machining precision is high.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation aircraft sheet metal parts processing, and relates to a method for forming a high-cone stainless steel oil leak base part. Background Art

[0002] The end of the aircraft fuel pipe needs to be sealed with an oil leak base, which is conical in shape. The height of the top of the cone from the bottom is generally about 30-50mm. The parts are usually made of stainless steel as the processing raw material, such as Figure 8 As shown. There are 11 narrow and long grooves with a width of 2mm on the conical oil leak bottom part. The narrow and long grooves need to be processed after the part is formed, and the processing accuracy is required to be plus or minus 0.2mm. This part is usually processed by the drop forming method (drop forming is to use the upper and lower molds to quickly close the molds to squeeze the middle sheet into shape), and then complete the trimming by manual hammering. Finally, the narrow and long grooves on the surface of the part are slotted with a cutting saw blade, and the processing is completed after filing with a round file.

[0003] At present, some parts processed by the above method will have the following three defects.

[0004] 1. Surface quality: Wrinkles or deep scratches caused by rapid mold closing cannot be eliminated by subsequent manual finishing due to the high strength of stainless steel, resulting in a certain scrap rate for parts.

[0005] 2. The conical surface of the part after drop forming will produce a certain degree of rebound, and a wooden hammer is needed to trim the taper to meet the requirements of part processing. It usually takes 2-3 hours to trim a part, with high labor costs and low processing efficiency.

[0006] 3. After the parts are processed, narrow and long grooves need to be cut on the surface. The width of the narrow grooves is inconsistent after processing using cutting saw blades. The primary processing tolerance is between plus or minus 1mm, and secondary filing is required to ensure plus or minus 0.2mm, resulting in low processing efficiency.

[0007] In order to further improve the coaxiality and taper slope error of parts after forming, the manufacturing accuracy of parts needs to be further improved. A new processing method is urgently needed to improve the processing accuracy and efficiency of parts. Summary of the invention

[0008] The purpose of the present invention is to invent a combined processing method for stainless steel high-cone parts, which realizes the composite processing of stainless steel high-cone parts by using four processing molds with different functions and three processing methods. And by using the calculation formula, the corresponding relationship between the taper of the part and the structural forming of the processing mold is realized, and the combination of spinning forming and electric spark machining is realized to finally realize the processing of such parts.

[0009] The technical solution of the present invention is as follows:

[0010] A method for forming a high-conical stainless steel oil drain base part, the steps are as follows:

[0011] The tooling used in the processing methods of the present invention for spinning, turning and electrospark machining comprises the following structure:

[0012] The spinning forming is composed of two sets of molds, the first set of molds is a spinning mold 1 ejector, a spinning mold 1 base, a spinning mold 1 tapered surface and a spinning mold 1 clamping handle, and the second set of molds is a spinning mold 2 ejector, a spinning mold 2 tapered surface, a spinning mold 2 base and a spinning mold 2 clamping handle;

[0013] The turning and cutting process is composed of a set of molds, which include a turning and cutting mold ejector pin, a turning and cutting mold conical support surface, a turning and cutting avoidance groove, a turning and cutting mold inner support surface, and a turning and cutting mold clamping handle;

[0014] The electrospark machining is composed of a set of molds, which include a lower mold, a lower mold positioning pin, a clamping pin, a fastening pin, an electrode sheet I, an electrode sheet II, and an upper die handle.

[0015] Step 1: Use spinning to process the part surface:

[0016] The ejector pin of the spinning die 1 is used for the first spinning forming, and a stainless steel sheet is placed between the ejector pin of the spinning die 1 and the conical surface of the spinning die 1, and the two are tightened to fix the sheet. The size of the conical surface of the spinning die 1 is determined according to the following method.

[0017] l = tan1 / 2θ×L+δ / r. Fig.10 shown.

[0018] The cross-sectional height of the conical surface of the spinning die 1 used in the first spinning forming is calculated by the above formula. The base of the spinning die 1 is connected to the conical surface of the spinning die 1. The length of the base of the spinning die 1 is calculated according to the bottom length of the part, which is 30-40mm greater than the bottom length of the part. A section of the spinning die 1 clamping handle is machined behind the base of the spinning die 1 so that it can be clamped in the jaws of the machine tool to maintain its rotation processing.

[0019] Step 2: Use the second set of molds to spin and form the final surface of the part:

[0020] The ejector pin of the spinning die 2 is used for the second spinning forming. The difference between this structure and the first spinning forming is that the surface of the ejector pin of the spinning die 2 is made with a corresponding conical groove according to the size of the top of the conical part, which is used for the conical surface of the top of the part to enter the forming when rotating. The size of the conical surface of the spinning die 2 is processed according to the conical size of the top of the part, and is used for rotating the conical surface. The size of the spinning die 2 base is also 30-40mm larger than the length of the bottom of the part. A section of the spinning die 2 clamping handle is processed behind the spinning die 2 base so that it can be clamped in the jaws of the machine tool to keep it rotating.

[0021] Step 3: Use turning process to process the bottom contour of the part

[0022] After the above processes are completed, the turning and cutting process begins, using a set of turning and cutting dies to complete the cutting of the bottom shape of the part.

[0023] Install the part on the conical support surface of the lathe, fix the part on the conical support surface of the lathe with the lathe ejector, and install the lathe clamping handle in the jaws of the lathe. After starting the machine, the tooling rotates with the lathe to make the part fit tightly on the inner support surface of the lathe, and use the cutting tool to cut in the lathe avoidance groove to complete the processing of the outer edge of the circular area at the bottom of the part, while avoiding cutting the mold.

[0024] Step 4: Use EDM to complete the processing of the narrow and long grooves on the inner surface of the part:

[0025] After completing the turning process, enter the EDM process, the purpose of this process is to process the narrow and long slot openings inside the parts. First, place the lower die on the processing platform, and use the lower die locating pin to fix the lower die in the pre-processed locating hole on the platform. Ensure its stability to facilitate maintaining accuracy during processing. Place a clamping pin above the lower die, and use the rotating fastening pins on both sides to press the part tightly against the lower die to prevent it from moving. After the clamping pin is tightened, press the electrode sheet I and the electrode sheet II tightly on the position where EDM is required for subsequent power-on processing. Electrode sheet I and electrode sheet II need to be processed according to the actual hole size inside the part to ensure the EDM accuracy and hole size after power-on. After completion, install the upper die handle on the platform above the equipment, and move the equipment platform downward to press the lower die, as shown below Fig. 9 shown.

[0026] Beneficial effects of the present invention:

[0027] By using multi-process forming tooling to process parts, high-tapered stainless steel parts can be accurately manufactured, reducing the marks of knocking and repair caused by manual forming, and improving the surface quality and processing efficiency of parts. At the same time, the narrow and long grooves on the inner surface of the parts are processed by EDM with high processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a side view of the spinning die 1;

[0029] Figure 2 It is a side view of the spinning die 2;

[0030] Figure 3 This is the side view of the car cutting die;

[0031] Figure 4 This is a top view of the EDM tooling;

[0032] Figure 5 It is the side view of the EDM tooling;

[0033] Figure 6 This is the front view of the EDM tooling;

[0034] Figure 7 This is a schematic diagram of the EDM installation;

[0035] Figure 8 This is a schematic diagram of the oil leak base;

[0036] Fig. 9 The schematic diagram is that the equipment platform moves downward to press the lower mold;

[0037] Fig.10 Schematic diagram of the conical surface dimensions of the spinning die 1.

[0038] In the figure: 1. ejector pin of spinning die 1; 2. base of spinning die 1; 3. conical surface of spinning die 1; 4. clamping handle of spinning die 1; 5. ejector pin of spinning die 2; 6. conical surface of spinning die 2; 7. base of spinning die 2; 8. clamping handle of spinning die 2; 9. ejector pin of turning die; 10. conical supporting surface of turning die; 11. avoiding groove of turning die; 12. inner supporting surface of turning die; 13. clamping handle of turning die; 14. lower die; 15. locating pin of lower die; 16. clamping pin; 17. fastening pin; 18. electrode sheet I; 19. electrode sheet II; 20. upper die handle. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific embodiments.

[0040] Embodiment 1:

[0041] The processing of this type of high-tapered stainless steel parts generally requires the use of three processing processes, including spinning, turning the outer shape, and EDM machining the inner shape.

[0042] Step 1: Use spinning to process the part profile, cut the stainless steel sheet into a circle, and the size of the circle after cutting is 30-50mm larger than the bottom diameter of the part to facilitate subsequent removal. Use the ejector 1 of the spinning die 1 to tightly attach the sheet to the conical surface 3 of the spinning die 1, and start the lathe at the same time, keeping the rotation speed of the base 2 of the spinning die 1 no more than 300 rpm to prevent the cone outer surface from wrinkling due to excessive speed during the first spinning process. After starting, use the universal sleeve on the machine tool to move forward, and gradually press the sheet on the surface of the conical surface 3 of the spinning die 1. After pressing, keep it for 1-2 minutes to prevent it from rebounding. After leaning, replace the universal sleeve again and move it forward so that the sheet outside the conical area is attached to the base 2 of the spinning die 1 to complete the first step.

[0043] Step 2: Use the second set of molds to spin-form the final surface of the part. Use the ejector pin 5 of the spinning mold 2 to tightly attach the part formed in the first step to the conical surface 6 of the spinning mold 2. At the same time, start the lathe and keep the rotation speed of the spinning mold 2 base 7 no more than 800 rpm to prevent the cone outer surface from breaking due to excessive speed during the second spinning process. After starting, move the spinning mold 2 base 8 forward and gradually push the part into the ejector pin 5 of the spinning mold 2 through the spinning process. This process forms the conical top part of the part. When the ejector pin 5 of the spinning mold 2 and the base 7 of the spinning mold 2 are fitted together, the second step is completed.

[0044] Step 3: Use the turning process to process the bottom contour of the part. Use the turning die ejector 9 and the turning die conical support surface 10 to press the formed part, start the lathe at the same time, keep the speed between 2000 rpm and 3000 rpm, use the milling cutter to gradually approach the turning avoidance groove 11, cut through the sheet and move to the connection between the turning avoidance groove 11 and the turning die conical support surface 10 until the milling cutter contacts the end surface of the turning die conical support surface 10. At this time, the circular contour of the bottom surface of the part is processed.

[0045] Step 4: Use EDM to complete the processing of the narrow and long grooves on the inner surface of the part. Remove the processed part, place it on the lower die 14, and fix it with the fastening pins 17 on both sides. Then install the electrode sheet I 18 and the electrode sheet II 19 to ensure that the electrode sheet is in close contact with the part, fix the electrode to the electrode chuck of the machine tool, move the electrode closer to the surface of the part, further adjust the position of the electrode chuck, and start processing the part after ensuring the position is accurate. After processing, lift the electrode chuck and check the processed hole to ensure that the part has no defects before removing the part, clean the part with a cleaning solution, and wipe the part clean with a rag.

[0046] Embodiment 2:

[0047] A method for forming a high-conical stainless steel oil drain base part, the steps are as follows:

[0048] The tooling used in the processing methods of the present invention for spinning, turning and electrospark machining comprises the following structure:

[0049] The spinning forming is composed of two sets of molds, the first set of molds is a spinning mold 1 ejector 1, a spinning mold 1 base 2, a spinning mold 1 tapered surface 3 and a spinning mold 1 clamping handle 4, and the second set of molds is a spinning mold 2 ejector 5, a spinning mold 2 tapered surface 6, a spinning mold 2 base 7, and a spinning mold 2 clamping handle 8;

[0050] The turning and cutting process is composed of a set of molds, which include a turning and cutting mold ejector pin 9, a turning and cutting mold conical support surface 10, a turning and cutting avoidance groove 11, a turning and cutting mold inner support surface 12, and a turning and cutting mold clamping handle 13;

[0051] The electrospark machining is composed of a set of molds, which include a lower mold 14, a lower mold positioning pin 15, a clamping pin 16, a fastening pin 17, an electrode sheet I 18, an electrode sheet II 19, and an upper die handle 20.

[0052] Step 1: Use spinning to process the part surface:

[0053] The spin die 1 ejector pin 1 is used for the first spin forming, and a stainless steel sheet is provided between the spin die 1 ejector pin 1 and the spin die 1 conical surface 3, and the two are tightened to fix the sheet. The size of the spin die 1 conical surface 3 is determined according to the following method.

[0054] l=tan1 / 2θ×L+δ / r, where θ is the horizontal section angle of the cone, L is the height from the top of the cone to the bottom, δ is the thickness of the part material, and r is the circular radius of the cone. Fig.10 shown.

[0055] The cross-sectional height of the conical surface 3 of the spinning die 1 used in the first spinning forming is calculated by the above formula. The base 2 of the spinning die 1 is connected to the conical surface 3 of the spinning die 1. The length of the base 2 of the spinning die 1 is calculated according to the bottom length of the part, which is 30-40mm greater than the bottom length of the part. A section of the spinning die 1 clamping handle 4 is machined behind the base 2 of the spinning die 1 so that it can be clamped in the jaws of the machine tool to maintain its rotation processing.

[0056] Step 2: Use the second set of molds to spin and form the final surface of the part:

[0057] The spin die 2 ejector pin 5 is used for the second spin forming. The difference between this structure and the first spin forming is that the surface of the spin die 2 ejector pin 5 is made with a corresponding conical groove according to the size of the top of the conical part, which is used for the top conical surface of the part to enter the forming when rotating. The size of the conical surface 6 of the spin die 2 is processed according to the conical size of the top of the part, and is used for rotating the conical surface. The size of the spin die 2 base 7 is also 30-40mm larger than the length of the bottom of the part. A section of the spin die 2 clamping handle 8 is processed behind the spin die 2 base 7 so that it can be clamped in the jaws of the machine tool to maintain its rotation processing.

[0058] Step 3: Use turning process to process the bottom contour of the part

[0059] After the above processes are completed, the turning and cutting process begins, using a set of turning and cutting dies to complete the cutting of the bottom shape of the part.

[0060] The part is mounted on the turning die conical support surface 10, the part is fixed on the surface of the turning die conical support surface 10 by the turning die ejector 9, and the turning die clamping handle 13 is mounted in the jaws of the lathe. After starting the machine tool, the tooling rotates with the machine tool to make the part fit tightly on the inner support surface 12 of the turning die, and the cutting tool is used to cut in the turning avoidance groove 11 to complete the processing of the outer edge of the circular area at the bottom of the part, while avoiding cutting the mold.

[0061] Step 4: Use EDM to complete the processing of the narrow and long grooves on the inner surface of the part:

[0062] After completing the turning process, enter the EDM process, the purpose of this process is to process the narrow and long slots inside the parts. First, place the lower die 14 on the processing platform, and use the lower die locating pin 15 to fix the lower die 14 in the pre-processed positioning hole on the platform. Ensure its stability to facilitate maintaining accuracy during processing. Place the clamping pin 16 above the lower die 14, and use the rotating fastening pins 17 on both sides to press the part tightly against the lower die 14 to prevent it from moving. After the clamping pin 16 is tightened, press the electrode sheet I18 and the electrode sheet II19 tightly to the position where EDM is required for subsequent power-on processing. The electrode sheet I18 and the electrode sheet II19 need to be processed according to the actual hole size inside the part to ensure the EDM accuracy and hole size after power-on. After completion, install the upper die handle 20 on the platform above the equipment, and move the equipment platform downward to press the lower die, as shown below Fig. 9 shown.

Claims

1. A method for forming a high-conical stainless steel oil drain base part. It is characterized in that Here are the steps: Step 1: Use spinning to process the part surface: A stainless steel sheet is provided between the ejector pin (1) of the spinning die 1 and the conical surface (3) of the spinning die 1, and the two are tightened to fix the sheet; The size of the conical surface (3) of the spinning die 1 is determined according to the following method; l = tan1 / 2θ×L+δ / r, where θ is the angle of the cone horizontal section, L is the height from the top of the cone to the bottom, δ is the thickness of the part material, and r is the radius of the cone ground circle; The cross-sectional height of the conical surface (3) of the spinning die 1 used in the first spinning forming is calculated by the above formula. The spinning die 1 base (2) is connected to the conical surface (3) of the spinning die 1. The length of the spinning die 1 base (2) is calculated according to the length of the bottom of the part and is 30-40 mm longer than the length of the bottom of the part. A section of the spinning die 1 clamping handle (4) is machined on the back of the spinning die 1 base (2) so that it can be clamped in the jaws of the machine tool to maintain its rotation processing; Step 2: Use the second set of molds to spin and form the final surface of the part: The surface of the ejector pin (5) of the spinning die 2 is provided with a corresponding conical groove according to the size of the top of the conical part, so as to allow the conical profile of the top of the part to enter into the forming process when the spinning die 2 is rotated; the size of the conical surface (6) of the spinning die 2 is processed according to the conical size of the top of the part, so as to be used for the rotation processing of the conical profile; the size of the base (7) of the spinning die 2 is also 30-40 mm larger than the length of the bottom of the part; a section of the clamping handle (8) of the spinning die 2 is processed behind the base (7) of the spinning die 2 so that the spinning die 2 can be clamped in the jaws of the machine tool to maintain its rotation processing; Step 3: Use turning process to process the bottom contour of the part The part is mounted on the conical support surface (10) of the lathe, the part is fixed on the surface of the conical support surface (10) of the lathe using a lathe ejector pin (9), and the lathe clamping handle (13) is mounted in the jaws of the lathe; after the lathe is started, the tooling rotates with the lathe so that the part fits tightly on the inner support surface (12) of the lathe, and a cutting tool is used to cut in the lathe avoidance groove (11) to complete the processing of the outer edge of the circular area at the bottom of the part, while avoiding cutting the mold; Step 4: Use EDM to complete the processing of the narrow and long groove position on the inner surface of the part After the turning process is completed, the electrospark machining process is entered. The purpose of this process is to machine the narrow and long slot opening inside the part. First, the lower die (14) is placed on the processing platform, and the lower die positioning pin (15) is used to fix the lower die (14) in the positioning hole pre-processed on the platform; a clamping pin (16) is placed above the lower die (14), and the fastening pins (17) on both sides are rotated to press the part tightly on the lower die (14) to prevent it from moving; after the clamping pin (16) is tightened, the electrode sheet I (18) and the electrode sheet II (19) are pressed tightly at the position where electrospark machining is required for subsequent power-on machining. The electrode sheet I (18) and the electrode sheet II (19) need to be machined according to the actual opening size inside the part to ensure the electrospark machining accuracy and opening size after power-on; after completion, the upper die handle (20) is installed on the platform above the equipment, and the equipment platform moves downward to press the lower die.

2. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 1, It is characterized in that The tooling used for the spinning, turning and electrospark machining comprises the following structure: The spin forming process is composed of two sets of molds. The first set of molds includes a spin mold 1 ejector pin (1), a spin mold 1 base (2), a spin mold 1 conical surface (3) and a spin mold 1 clamping handle (4). The second set of molds includes a spin mold 2 ejector pin (5), a spin mold 2 conical surface (6), a spin mold 2 base (7) and a spin mold 2 clamping handle (8).

3. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 1 or 2, It is characterized in that The turning and cutting process is composed of a set of molds, which include a turning and cutting mold ejector pin (9), a turning and cutting mold conical supporting surface (10), a turning and cutting avoiding groove (11), a turning and cutting mold inner supporting surface (12), and a turning and cutting mold clamping handle (13).

4. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 1 or 2, It is characterized in that The electrospark machining is composed of a set of molds, which include a lower mold (14), a lower mold positioning pin (15), a clamping pin (16), a fastening pin (17), an electrode sheet I (18), an electrode sheet II (19), and an upper die handle (20).

5. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 3, It is characterized in that The electrospark machining is composed of a set of molds, which include a lower mold (14), a lower mold positioning pin (15), a clamping pin (16), a fastening pin (17), an electrode sheet I (18), an electrode sheet II (19), and an upper die handle (20).

6. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 1, 2 or 5, It is characterized in that In the second step, the rotation speed of the base body (7) of the spinning mold 2 is maintained at no more than 800 revolutions per minute.

7. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 3, It is characterized in that In the second step, the rotation speed of the base body (7) of the spinning mold 2 is maintained at no more than 800 revolutions per minute.

8. A method for forming a high-conical stainless steel oil drain base part as claimed in claim 4, It is characterized in that In the second step, the rotation speed of the base body (7) of the spinning mold 2 is maintained at no more than 800 revolutions per minute.

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