Method for machining convex macroannular parts

Abstract

The application discloses a machining method of convex large annular parts, which comprises the following steps of material preparation, blanking, paint spraying, first-time bending, second-time bending, shape correction, end grinding and paint removal. The machining method can complete the cross-section characteristics and bending radius of the convex large annular parts by only using the bending and shape correction modes, the die design and manufacturing cost are low, the machining time is short, the efficiency is high, and the forming quality meets the research and development requirements.

Description

Technical Field

[0001] This invention belongs to the aerospace field and involves sheet metal forming, mold design and manufacturing, accurate calculation of raw materials and planar unfolding, and sheet metal simulation methods. Background Technology

[0002] The large convex ring-shaped part has a convex semi-closed cross-section and an overall shape of a semi-circle with a diameter exceeding 1 meter. The part's structural diagram is shown below. Figure 1 , 2 As shown in the figure (H1, H2, R1, R2, R3, R, h, A, L are all characteristic dimensions of the convex large annular part; it should be noted that the dimension L at the opening has two cases: one is L < H2, and the other is L > H2), Figure 2 (Only the case where L > H2 is shown in the diagram). The part is machined from 1mm thick stainless steel sheet. Due to the convex irregular cross-section and large size of the part, there are difficulties in machining, tooling design, and tooling manufacturing during actual on-site production.

[0003] For convex large ring parts, it is difficult to process such parts in one go using traditional bulging or bending processes, which leads to a longer part development and processing cycle and an increase in tooling costs. Summary of the Invention

[0004] This invention aims to provide a processing method for convex large ring parts, master the rapid prototyping approach for large ring structure parts with convex cross-sectional features, and master the surface control method, simple tooling structure design and manufacturing ideas for such parts, so as to achieve the purpose of processing complex surface parts with simple molds and effectively improve the processing efficiency of parts.

[0005] The technical solution of the present invention is as follows:

[0006] A method for machining a convex large annular part, wherein the cross-section of the convex large annular part includes an upwardly convex first protrusion, a leftwardly convex second protrusion to the left of the first protrusion, and a rightwardly convex third protrusion to the right. The machining method includes the following steps.

[0007] Step 1, Material preparation: Select a sheet metal with the same final thickness as the convex large ring part;

[0008] Step 2, material preparation: cut the board material from Step 1 into rectangles;

[0009] Step 3, spray painting, forming a protective and lubricating film layer on the surface of the rectangular board obtained in step 2;

[0010] Step 4, First bending: Use the first bending die to bend the rectangular sheet to obtain an intermediate blank with the cross-sectional characteristics of a convex large ring part. The cross-section of the intermediate blank includes a straight main body, the left end of the main body is a second protrusion that has been formed but faces upward, and the right end of the main body is a third protrusion that has been formed but faces upward.

[0011] Step 5, second bending: the intermediate blank obtained in step 4 is bent using the second bending die. The first protrusion is formed on the main body of the intermediate blank, and the protrusion direction of the second protrusion is adjusted to the left and the protrusion direction of the third protrusion is adjusted to the right, so as to obtain a second bending blank with all the cross-sectional features of the convex large ring part.

[0012] Step 6, Shaping: The cross-sectional shape of the blank material that was bent twice in Step 5 is shaped using a shaping mold to obtain a bending radius with a certain curvature (i.e., the cross-section is shaped while the bending is rolled), and the bending radius is gradually corrected to obtain the shaped blank material.

[0013] Step 7: Grinding. Grind the two ends of the blank after shaping to ensure that the length of the convex ring part is qualified.

[0014] Step 8, paint removal, remove the film layer from step 3.

[0015] Alternatively, in step 2, laser cutting is used for material preparation.

[0016] Alternatively, in step 2, the length and width dimensions of the rectangle are calculated by unfolding the sheet metal into a large convex annular part, or by calculating the linear length of the neutral layer of the large convex annular part.

[0017] Alternatively, in step 4, the first bending die includes an upper die and a lower die, wherein:

[0018] The upper die-cutting surface includes a first protrusion for forming a second protrusion and a second protrusion for forming a third protrusion;

[0019] The forming surface of the lower die includes a first groove for forming a second protrusion and a second groove for forming a third protrusion.

[0020] Alternatively, in step 5, the length of the main body between the second and third protrusions on the middle fabric in step 4 is used as the positioning reference for the second bending.

[0021] Alternatively, in step 5, the second bending die includes an upper die and a lower die, wherein:

[0022] The upper die includes a third protrusion for forming the first protrusion, and a clearance step is formed on the left and right sides of the third protrusion (the clearance step needs to be designed when the opening size L < H2).

[0023] The lower die includes a third groove for forming the first protrusion. The left and right sides of the third groove are a first positioning block and a second positioning block, respectively. The straight-line distance from the left side of the first positioning block to the right side of the second positioning block is equal to the length of the main body on the middle blank.

[0024] Alternatively, in step 6, a correction roller is used to correct the cross-sectional shape and bending radius of the secondary bending material. The correction is performed using a progressive, small curvature feed method.

[0025] Alternatively, in step 6, the cross-sectional shape and bending radius of the secondary bent material are corrected multiple times using a correction roller, with the correction number being no less than two times.

[0026] Alternatively, in step 6, the correction roller includes an upper roller and a lower roller, and the upper roller and the lower roller form a space for correcting the cross-sectional shape and bending radius of the secondary bending of the fabric.

[0027] Alternatively, in step 8, the membrane layer is removed with alkaline water and then rinsed with clean water.

[0028] Compared with existing processing methods, the present invention has the following advantages:

[0029] (1) The processing method of the present invention is simple. The convex large ring part is processed by a combination of simple bending forming, rolling bending and straightening methods.

[0030] (2) Compared with traditional bulging or bending forming, the parts formed by the present invention have no reduction in material thickness and a short processing cycle.

[0031] (3) The processing cost of the present invention is low. The tooling used for processing convex large ring parts is simpler to design and manufacture than traditional bulging and bending tooling, and the tooling processing cost is low. For example, the present invention only requires two sets of bending dies and one set of rollers. In comparison, traditional forming requires one set of molds nearly 2m long and one set of bending tooling.

[0032] The processing method of this invention is currently being used in the field, achieving the objective of this invention. Attached Figure Description

[0033] Figure 1 This is a three-dimensional schematic diagram of a convex large annular part;

[0034] Figure 2 This is a two-dimensional schematic diagram of a convex large annular part;

[0035] Figure 3 This is a schematic diagram of a rectangular sheet material during the cutting process;

[0036] Figure 4 and Figure 5 This is a schematic diagram of the upper and lower die in the first bending die (die);

[0037] Figure 6 This is a schematic diagram of the intermediate raw material;

[0038] Figure 7 This is a schematic diagram of the second bending die (cutting die);

[0039] Figure 8 and Figure 9 These are schematic diagrams of the upper and lower rollers used for alignment. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0041] like Figures 3-9 The diagram illustrates the processing method for a convex large annular part according to the present invention, which specifically includes the following steps:

[0042] Step 1: Material preparation: Prepare the required thickness of sheet metal according to the drawings. The sheet metal thickness requirement should be consistent with the final material thickness requirement of the part.

[0043] Step 2, Laser Cutting: A laser cutting machine is used to cut the sheet metal into rectangular strips with fixed lengths x widths. The final dimensions are calculated based on the unfolded sheet metal of the convex large ring part (e.g., ...). Figure 3 (As shown), it can also be calculated by calculating the linear length of the neutral layer (middle of the material thickness) of the convex large annular part.

[0044] Step 3, Spray painting: Form a protective film on the surface of the rectangular board to prevent the rectangular board from directly contacting the bending and straightening mold, thus providing protection and lubrication.

[0045] Step 4, First bending: Place the upper die ( Figure 4 ) and lower die ( Figure 5 The rectangular sheet is fixed on the bending machine. It is placed on the bending die, and the positioning blocks of the bending machine are adjusted to ensure that the rectangular sheet is symmetrically positioned at the center of the upper and lower dies, preventing misalignment and resulting in defective bending. The rectangular sheet is then bent into an intermediate blank for transition. The structure of the intermediate blank is as follows... Figure 6 As shown.

[0046] Step 5, Second Bending: Place the sheet metal after the first bending onto another set of bending dies, such as... Figure 7 The intermediate blank is positioned using the width h1 of the die (i.e., Figure 5 h1 is placed in Figure 7 At point h1 (where h1 is the initial bending width that conforms to the final width of the convex large annular part after forming), the intermediate blank is bent a second time after fixing. When designing the upper die for the second bend, because the final opening width of the convex large annular part is smaller than the width of the bent section (i.e.,...),... Figure 2 The opening width L corresponding to the middle AA section is less than the width H2 of the first protrusion, therefore the upper die is as follows: Figure 7 The area shown needs to be designed as a detour.

[0047] Step 6, Roll Bending and Shaping: Shaping the part after the second bend requires a progressive small curvature feed method (progressive means the upper and lower rollers feed gradually from small to large, rather than feeding all at once. Small curvature means that during the roller shaping process, a relatively small curvature is initially applied, and then the curvature is gradually increased with each roll bend). To ensure a smooth and undeformed final surface, shaping should be performed at least 4-6 times to guarantee the final arc dimension of the part. The rollers used for shaping include... Figure 8 and Figure 9 As shown (Φ1, Φ2, Φ3, Φ4, Φ5, L1, L2, L3, L4, and L5 in the figure are all characteristic dimensions of the rollers), it is achieved by a combination of upper and lower rollers pressing down and pushing up.

[0048] Step 7: Grind both ends: Grind both ends of the shaped part to ensure the final arc length dimension of the part (i.e., Figure 2 (The arc length of the circle in the middle right figure).

[0049] Step 8: Paint Removal: Use alkaline water to remove the paint layer from the surface of the parts, and then rinse with clean water to keep the surface of the parts clean.

[0050] The contents not described in detail in this specification are prior art known to those skilled in the art. Although the present invention has been described in detail above, it should be understood that the present invention is not limited to the scope of the specific embodiments, but should be defined by the scope of the claims.

Claims

1. A method for processing a convex large annular part, wherein the cross-section of the convex large annular part includes an upwardly convex first protrusion, a leftwardly convex second protrusion to the left of the first protrusion, and a rightwardly convex third protrusion to the right, characterized in that: The processing method includes the following steps: Step 1, Material preparation: Select a sheet metal with the same final thickness as the convex large ring part; Step 2, material preparation: cut the board material from Step 1 into rectangles; Step 3, spray painting, forming a protective and lubricating film layer on the surface of the rectangular board obtained in step 2; Step 4, First bending: Use the first bending die to bend the rectangular sheet to obtain an intermediate blank with the cross-sectional characteristics of a convex large ring part. The cross-section of the intermediate blank includes a straight main body, the left end of the main body is a second protrusion that has been formed but faces upward, and the right end of the main body is a third protrusion that has been formed but faces upward. Step 5, second bending: the intermediate blank obtained in step 4 is bent using the second bending die. The first protrusion is formed on the main body of the intermediate blank, and the protrusion direction of the second protrusion is adjusted to the left and the protrusion direction of the third protrusion is adjusted to the right, so as to obtain a second bending blank with all the cross-sectional features of the convex large ring part. Step 6, roll bending and shaping: While using a shaping mold to shape the cross-sectional shape of the secondary bending of the raw material in step 5, roll bending is performed to obtain a bending radius with a certain curvature, and the bending radius is gradually corrected to obtain the shaped raw material. Step 7: Grinding. Grind the two ends of the blank after shaping to ensure that the length of the convex ring part is qualified. Step 8, paint removal, removing the film layer from step 3; In step 4, the first bending die includes an upper die and a lower die, wherein: The upper die-cutting surface includes a first protrusion for forming a second protrusion and a second protrusion for forming a third protrusion; The forming surface of the lower die includes a first groove for forming a second protrusion and a second groove for forming a third protrusion. In step 5, the second bending die includes an upper die and a lower die, wherein: The upper die includes a third protrusion for forming the first protrusion, and an avoidance step is formed on the left and right sides of the third protrusion; The lower die includes a third groove for forming the first protrusion. The left and right sides of the third groove are a first positioning block and a second positioning block, respectively. The straight-line distance from the left side of the first positioning block to the right side of the second positioning block is equal to the length of the main body on the middle blank.

2. The processing method for the convex large annular part according to claim 1, characterized in that: In step 2, laser cutting is used to cut the material.

3. The processing method for the convex large annular part according to claim 1, characterized in that: In step 2, the length and width of the rectangle are calculated by unfolding the sheet metal into a large convex annular part, or by calculating the linear length of the neutral layer of the large convex annular part.

4. The processing method for the convex large annular part according to claim 1, characterized in that: In step 5, the length of the main body between the second and third protrusions on the middle material in step 4 is used as the positioning reference for the second bending.

5. The processing method for the convex large annular part according to claim 1, characterized in that: In step 6, a correction roller is used to correct the cross-sectional shape and bending radius of the secondary bending material. The correction is performed using a progressive, small curvature feed method.

6. The processing method for the convex large annular part according to claim 1, characterized in that: In step 6, the cross-sectional shape and bending radius of the secondary bent material are corrected multiple times using a correction roller, with the correction number being no less than two times.

7. The processing method for the convex large annular part according to claim 1, characterized in that: In step 6, the correction rollers include an upper roller and a lower roller, and a space for correcting the cross-sectional shape and bending radius of the secondary bending material is formed between the upper roller and the lower roller.

8. The processing method for the convex large annular part according to claim 1, characterized in that: In step 8, the membrane layer is removed with alkaline water and then rinsed with clean water.

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