A forming method for a high-tapered stainless steel oil pan base part

Abstract

The present application belongs to the technical field of aircraft sheet metal part processing, and relates to a forming method of a high-cone-shaped stainless steel oil drain base part. After the part is processed by using a multi-process forming tool, the high-cone-shaped stainless steel part can be accurately manufactured, the knocking marks caused by manual forming are reduced, and the surface quality and processing efficiency of the part are improved. Meanwhile, after the narrow and long groove on the inner surface of the part is processed by using an electric spark method, the processing precision is high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft sheet metal part processing, and relates to a forming method for a high-cone-shaped stainless steel oil leakage base part. BACKGROUND

[0002] An oil leakage base is used to close the end of an aircraft fuel conduit, and the shape of the oil leakage base is a cone. The height of the cone top from the bottom surface is generally about 30-50 mm, and the part material is usually stainless steel material as a processing raw material, as shown in the drawings. There are 11 narrow and long grooves with a width of 2 mm on the cone-shaped oil leakage base part, and the narrow and long grooves need to be processed after the part is formed. The processing precision is required to be within plus or minus 0.2 mm. The part is usually processed by drop press forming (drop press forming is to use upper and lower molds to extrude and form the middle plate), and then is finished by combining with manual knocking. Finally, the narrow and long grooves on the surface of the part are cut by using a cutting saw, and are finished by using a round file. Figure 8

[0003] Currently, the parts processed by using the above method have the following three defects.

[0004] 1. Surface quality is wrinkled or scratched due to rapid mold closing. Since the stainless steel material has high strength, the subsequent manual finishing method cannot eliminate the defects, and the part has a certain scrap rate.

[0005] 2. The cone surface of the part after drop press forming has a certain degree of springback, and the cone degree needs to be adjusted by using a wooden hammer to meet the processing requirements of the part. Usually, it takes 2-3 hours to adjust one part, the labor cost is high, and the processing efficiency is low.

[0006] 3. The narrow grooves on the surface of the part need to be cut after the part is processed. The width of the narrow grooves is inconsistent after being processed by using a cutting saw, the one-time processing tolerance is between plus or minus 1 mm, and the narrow grooves need to be finished twice to ensure that the width is within plus or minus 0.2 mm, so the processing efficiency is low.

[0007] In order to further improve the coaxiality and the cone surface slope error of the part after forming, the manufacturing precision of the part needs to be further improved, and a new processing method is urgently needed to improve the processing precision and the processing efficiency of the part. SUMMARY

[0008] The purpose of the application is to invent a combined processing method for a stainless steel high-cone-shaped part. The combined processing method is realized by using four different function processing molds and three combined processing methods. The structure of the processing mold is formed according to the corresponding relationship between the cone degree of the part and the structure of the processing mold. The combined method of spinning forming and electric spark processing is used to finally realize the processing of the part. ​

[0009] The technical scheme of the present application is as follows:

[0010] A forming method of a high-cone stainless steel oil pan base part, steps are as follows:

[0011] The tooling used in the spinning forming, turning and cutting processing and the electrical discharge machining of the processing method of the present application 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 thimble, a spinning mold 1 base, a spinning mold 1 conical surface and a spinning mold 1 clamping handle, and the second set of molds is a spinning mold 2 thimble, a spinning mold 2 conical surface, a spinning mold 2 base and a spinning mold 2 clamping handle.

[0013] The turning and cutting processing is composed of one set of molds, and the mold is a turning and cutting mold thimble, 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 electrical discharge machining is composed of one set of molds, and the mold is a lower mold, a lower mold positioning pin, a mold closing pin, a fastening pin, an electrode sheet I, an electrode sheet II and an upper pressing mold handle.

[0015] First step: use spinning forming to process the part surface:

[0016] The spinning mold 1 thimble is used for the first time of spinning forming, and the spinning mold 1 thimble and the spinning mold 1 conical surface are stainless steel plates, and the two are tightened to fix the plate. The size of the spinning mold 1 conical surface is determined according to the following method.

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

[0018] The cross-sectional height of the mold spinning mold 1 conical surface used for the first time of spinning forming is calculated by the above formula, the spinning mold 1 base and the spinning mold 1 conical surface are connected together, the length of the spinning mold 1 base is calculated according to the length of the part bottom, which is greater than the length of the part bottom by 30-40 mm. A spinning mold 1 clamping handle is processed at the back of the spinning mold 1 base, so that it can be clamped in the machine tool jaw and kept rotating.

[0019] Second step: use the second set of molds to spin form the final part surface:

[0020] ​The spinning die 2 ejector pin is used for the second spinning forming, and the difference between the structure and the first spinning forming is that a conical groove is formed on the surface of the spinning die 2 ejector pin according to the size of the top of the conical part, and the top of the conical part is used for entering the forming when spinning. The size of the conical surface of the spinning die 2 is processed according to the size of the top of the conical part, and is used for processing the conical surface. The size of the base body of the spinning die 2 is also greater than the length of the bottom of the part by 30-40 mm. A spinning die 2 clamping handle is processed on the back of the base body, so that it can be clamped in the jaws of the machine tool and kept rotating.

[0021] Third step: using turning process to process the bottom contour of the part

[0022] After the above process is completed, the turning process is entered, and a set of turning dies is used to complete the cutting of the bottom contour of the part.

[0023] The part is installed on the conical support surface of the turning die, and the part is fixed on the surface of the conical support surface of the turning die by the turning die ejector pin. The turning die clamping handle is installed in the jaws of the lathe. After starting the machine tool, the tooling rotates with the machine tool to make the part tightly fit on the inner support surface of the turning die, and the cutting tool is used to cut in the turning avoidance groove to process the outer edge of the circular area at the bottom of the part, which can avoid cutting the die.

[0024] Fourth step: using electric spark processing to complete the processing of the narrow and long groove position of the inner surface of the part

[0025] After the turning process is completed, the electric spark processing process is entered, and the purpose of this process is to process the narrow and long groove opening in the part. First, the lower die is placed on the processing platform, and the lower die is fixed in the pre-processed positioning hole in the platform by using the lower die positioning pin. Ensure its stability, facilitate the accuracy during processing. The upper die is placed on the lower die, and the part is tightly pressed on the lower die by using the rotating two side fastening pins, so as to prevent the part from moving. After the die pin is fastened, the electrode sheet I and the electrode sheet II are tightly pressed on the position needing electric spark processing, which is used for subsequent electric processing. The electrode sheet I and the electrode sheet II need to be processed according to the actual opening size of the inner surface of the part, so as to ensure the electric spark processing accuracy and the opening size after electric processing. After completion, the upper pressing die handle is installed on the upper platform of the equipment, and the equipment platform moves downward to press the lower die, as shown in the following figure. Figure 9

[0026] Advantages of the present application:

[0027] After the part is processed by using the multi-process forming tooling, the high conical stainless steel part can be accurately manufactured, the knocking marks caused by manual forming are reduced, and the surface quality and processing efficiency of the part are improved. At the same time, after the narrow and long groove on the inner surface of the part is processed by using the electric spark method, the processing precision is high. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0030] Figure 3 is a side view of the turning die;

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

[0032] Figure 5 is a side view of the EDM tool;

[0033] Figure 6 is a front view of the EDM tool;

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

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

[0036] Figure 9 is a schematic diagram of the downward movement of the equipment platform to press the lower die tightly;

[0037] Figure 10 is a schematic diagram of the size of the conical surface of the spinning die 1.

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

[0039] The application will be further described below in combination with specific embodiments.

[0040] Example 1:

[0041] Such high-cone stainless steel parts generally require the use of three processing procedures, including spinning forming, turning the shape, and EDM processing the inner shape.

[0042] First step: using spinning forming process parts profile, cutting stainless steel sheet into a circle, cutting size circle is larger than the part bottom diameter 30-50mm, which is convenient for subsequent removal. Using spinning die 1 ejector pin 1 to tightly stick the sheet on the spinning die 1 conical surface 3, and start the lathe, keeping the spinning die 1 base 2 rotation speed not more than 300rpm, to prevent the first spinning process speed too fast causing the conical surface wrinkling. After starting, using the general sleeve on the machine to move forward, and gradually press the sheet on the spinning die 1 conical surface 3, and keep 1-2 minutes after pressing to prevent springback. After the die, change the general sleeve again, and move it forward to make the sheet stick on the spinning die 1 base 2, and complete the first step.

[0043] Second step: using the second set of spinning die to form the final profile of the part, using the spinning die 2 ejector pin 5 to tightly stick the first step formed part on the spinning die 2 conical surface 6, and start the lathe, keeping the spinning die 2 base 7 rotation speed not more than 800rpm, to prevent the second spinning process speed too fast causing the conical surface cracking. After starting, move the spinning die 2 base 8 forward, and gradually push the part into the spinning die 2 ejector pin 5 to form the conical top end of the part. When the spinning die 2 ejector pin 5 and the spinning die 2 base 7 are stuck together, the second step is completed.

[0044] Third step: using the turning process to process the bottom profile of the part. Using the turning die ejector pin 9 and the turning die conical support surface 10 to press the formed part, and start the lathe, keeping the rotation speed between 2000rpm-3000rpm, and gradually approach the turning avoidance groove 11 using the milling cutter, move to the connection between the turning avoidance groove 11 and the turning die conical support surface 10 after cutting through the sheet, until the milling cutter contacts the end surface of the turning die conical support surface 10, at which time the circular profile of the bottom surface of the part is completed.

[0045] Fourth step: using the electric spark processing method to complete the processing of the narrow and long groove on the inner surface of the part. Take the above processed part and place it on the lower die 14, and fix it using the fastening pins 17 on both sides. Then install the electrode sheet I 18 and the electrode sheet II 19, ensure that the electrode sheet is in close contact with the part, fix the electrode to the electrode holder of the machine tool, move the electrode close to the surface of the part, further adjust the position of the electrode holder to ensure the accuracy of the position, and then start processing the part. After processing, lift the electrode holder, check the processed hole to ensure that the part has no defects, and then remove the part, clean the part with a cleaning solution, and wipe the part clean with a cloth.

[0046] Example 2:

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

[0048] The tooling used in the processing mode of spinning forming, turning and cutting and electric spark machining comprises the following structure:

[0049] The spinning forming comprises two sets of molds, the first set of molds being a spinning mold 1 pin 1, a spinning mold 1 base 2, a spinning mold 1 conical surface 3 and a spinning mold 1 clamping handle 4, and the second set of molds being a spinning mold 2 pin 5, a spinning mold 2 conical surface 6, a spinning mold 2 base 7 and a spinning mold 2 clamping handle 8.

[0050] The turning and cutting processing comprises one set of molds, the molds being a turning and cutting mold 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 electric spark machining comprises one set of molds, the molds being a lower mold 14, a lower mold positioning pin 15, a mold closing pin 16, a fastening pin 17, an electrode piece I 18, an electrode piece II 19 and an upper mold handle 20.

[0052] First step: using spinning forming to process the part profile:

[0053] The spinning mold 1 pin 1 is used for the first time of spinning forming, and the spinning mold 1 pin 1 and the spinning mold 1 conical surface 3 are stainless steel plates, and the two are tightened to fix the plate. The size of the spinning mold 1 conical surface 3 is determined according to the following method.

[0054] l = tan 1 / 2 θ × L + δ / r, wherein θ is the conical horizontal section angle, L is the distance from the top of the cone to the bottom, δ is the thickness of the part material, and r is the radius of the conical ground circle. As shown in Figure 10 .

[0055] The cross-sectional height of the mold spinning mold 1 conical surface 3 used for the first time of spinning forming is calculated by the above formula, the spinning mold 1 base 2 is connected with the spinning mold 1 conical surface 3, the length of the spinning mold 1 base 2 is calculated according to the length of the bottom of the part, and is greater than the length of the bottom of the part by 30-40 mm. A spinning mold 1 clamping handle 4 is machined at the back of the spinning mold 1 base 2, so that it can be clamped in the machine tool jaw and kept rotating.

[0056] Second step: using the second set of molds to process the final profile of the part by spinning forming:

[0057] The spinning die 2 ejector pin 5 is used for the second spinning process. This structure differs from the first spinning process in that the surface of the spinning die 2 ejector pin 5 has a corresponding tapered groove made according to the top dimension of the tapered part, allowing the tapered surface of the part's top to enter the forming process during rotation. The tapered surface 6 of the spinning die 2 is machined according to the top tapered dimension of the part, used for rotating and machining the tapered surface. The size of the spinning die 2 base 7 is also 30-40mm larger than the bottom length of the part. A section of the spinning die 2 clamping handle 8 is machined at the rear of the spinning die 2 base 7, allowing it to be clamped in the machine tool jaws and maintained for rotational machining.

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

[0059] After the above processes are completed, the turning process begins, where a set of turning dies is used to cut the bottom shape of the part.

[0060] The part is mounted on the tapered support surface 10 of the cutting die, and the part is fixed to the surface of the tapered support surface 10 using the cutting die ejector pin 9. The cutting die clamping handle 13 is installed in the lathe jaws. After starting the machine tool, the fixture rotates with the machine tool to make the part fit tightly against the inner support surface 12 of the cutting die. The cutting tool is used to cut in the cutting avoidance groove 11 to complete the outer edge of the bottom circular area of ​​the part, while avoiding damage to the die.

[0061] Step 4: Use electrical discharge machining (EDM) to machine the narrow, elongated groove on the inner surface of the part.

[0062] After the turning process is completed, the electrical discharge machining (EDM) process begins. This process is for machining narrow, elongated slots and openings inside the part. First, the lower die 14 is placed on the machining platform, and the lower die 14 is fixed in the pre-machined positioning holes on the platform using the lower die positioning pin 15. This ensures stability and facilitates maintaining accuracy during machining. The mold-closing pin 16 is placed above the lower die 14, and the workpiece is pressed tightly onto the lower die 14 using rotating side-mounted fastening pins 17 to prevent movement. After the mold-closing pin 16 is tightened, electrode plates I 18 and II 19 are pressed tightly onto the positions requiring EDM machining for subsequent electrical discharge machining. Electrode plates I 18 and II 19 need to be machined according to the actual opening size inside the part to ensure the accuracy and opening size of the EDM machining after power is applied. After completion, the upper die handle 20 is installed on the platform above the equipment. The equipment platform moves downwards to press the lower die firmly, as shown below. Figure 9 As shown.

Claims

1. A method of forming a high-tapered stainless steel oil pan base part, characterized by, The steps are as follows: First step: use spinning forming process part profile: First spinning die ejector pin (1) and first spinning die taper surface (3) between stainless steel sheet, both of which are fixed by tightening the sheet; The size of the first spinning die taper surface (3) is determined according to the following method; L= (tan (1 / 2) θ) × L + δ / r, wherein θ is the angle of the taper horizontal section, L is the height of the taper top distance from the bottom surface, δ is the thickness of the part material, and r is the radius of the taper bottom surface; The height of the taper top distance from the bottom surface of the first spinning die taper surface (3) used in the first spinning forming is calculated by the above formula. The first spinning die base (2) is connected with the first spinning die taper surface (3). The length of the first spinning die base (2) is calculated according to the length of the part bottom, which is greater than the length of the part bottom by 30-40mm. A first spinning die clamping handle (4) is processed at the back of the first spinning die base (2), which can be clamped in the machine tool jaw and kept rotating. Second step: use the second set of mold spinning forming process to process the final profile of the part: The surface of the second spinning die ejector pin (5) is made into a corresponding taper groove according to the size of the taper part top, which is used for the part top taper profile into forming when rotating; The size of the second spinning die taper surface (6) is processed according to the size of the part top taper, which is used for rotating the taper profile. The size of the second spinning die base (7) is also greater than the length of the part bottom by 30-40mm. A second spinning die clamping handle (8) is processed at the back of the second spinning die base (7), which can be clamped in the machine tool jaw and kept rotating. Third step: use turning process to process the part bottom contour Install the part on the turning die taper support surface (10), and fix the part on the turning die taper support surface (10) surface with the turning die ejector pin (9). Install the turning die clamping handle (13) in the lathe jaw. After starting the machine tool, the tooling rotates with the machine tool to make the part tightly fit on the turning die inner support surface (12). Use the cutting tool to cut in the turning avoidance groove (11) to process the outer edge of the part bottom circular area. At the same time, it can avoid cutting the mold; Fourth step: use electric spark processing method to complete the processing of the narrow and long groove position of the part inner surface After the turning process is completed, the electric spark processing process is entered. The purpose of this process is to process the internal narrow and long groove opening of the part. First, place the lower die (14) on the processing platform, and fix the lower die (14) in the pre-processed positioning hole of the platform by using the lower die positioning pin (15). Place the die pin (16) above the lower die (14), and use the rotating two side fastening pins (17) at the same time. Press the part tightly on the lower die (14) to prevent it from moving. After the die pin (16) is fastened, press the electrode sheet I (18) and the electrode sheet II (19) tightly on the position where electric spark processing is needed for subsequent electric processing. The electrode sheet I (18) and the electrode sheet II (19) need to be processed according to the actual opening size of the part inner surface to ensure the electric spark processing accuracy and opening size after electric processing. After completion, install the upper pressing die handle (20) on the equipment platform above. Move the equipment platform downward to press the lower die tightly.

2. A method of forming a high-cone stainless steel oil pan component part as set forth in claim 1, wherein, The spinning forming, turning and electrical discharge machining tooling comprises the following structure: The spinning forming tooling is composed of two sets of molds, the first set of molds is a first spinning mold thimble (1), a first spinning mold base (2), a first spinning mold tapered surface (3) and a first spinning mold clamping handle (4), and the second set of molds is a second spinning mold thimble (5), a second spinning mold tapered surface (6), a second spinning mold base (7) and a second spinning mold clamping handle (8).

3. A method of forming a high-cone stainless steel oil pan component part as set forth in claim 2 wherein, The turning tooling is composed of one set of molds, and the molds are turning mold thimble (9), turning mold tapered support surface (10), turning avoidance groove (11), turning mold inner support surface (12) and turning mold clamping handle (13).

4. A method of forming a high-cone stainless steel oil pan component part as set forth in claim 1 or 2, characterized in that, The electrical discharge machining tooling is composed of one set of molds, and the molds are lower mold (14), lower mold positioning pin (15), mold closing pin (16), fastening pin (17), electrode piece I (18), electrode piece II (19) and upper mold handle (20).

5. A method of forming a high-cone stainless steel oil pan component part as set forth in claim 3, wherein, The electrical discharge machining tooling is composed of one set of molds, and the molds are lower mold (14), lower mold positioning pin (15), mold closing pin (16), fastening pin (17), electrode piece I (18), electrode piece II (19) and upper mold handle (20).

6. A method of forming a high-cone stainless steel oil pan component as set forth in claim 1 or 2 or 5, characterized in that, In the second step, the rotation speed of the second spinning mold base (7) is kept not more than 800 rpm.

7. A method of forming a high-cone stainless steel oil pan component part as set forth in claim 3, wherein, In the second step, the rotation speed of the second spinning mold base (7) is kept not more than 800 rpm.

8. A method of forming a high-cone stainless steel oil pan component part as set forth in claim 4, wherein, In the second step, the rotation speed of the second spinning mold base (7) is kept not more than 800 rpm.

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