A large head stamping forming demolding method

Abstract

The application discloses a large-scale head stamping forming demolding method, and uses a demolding tool, which comprises a clamping part, a bifurcated structure and an extension part, and comprises the following steps: 1, clamping the clamping part of the demolding tool on the operating machine matched with the forging press, moving the holding tool through the operating machine, and rotating the holding tool around the axis of the clamping part; 2, after the head stamping is completed, the punch is lifted upward, if the head cannot be demolded from the punch naturally, the demolding tool is moved to the two extension parts which are respectively located on the two sides of the punch by the operating machine, and the two extension parts are respectively corresponding to the end faces of the head opening ends located on the two sides of the punch; 3, moving the demolding tool by the operating machine, and applying pressure to the end face of the head opening end by the extension part, so that the head is separated from the punch. The application can solve the technical problem that the free forging press equipment cannot timely deal with the situation that the head formed by stamping forming is not ball-shaped or has straight edges and the forged piece is stuck to the punch after forming.

Description

Technical Field

[0001] This invention relates to the field of pressure vessel forging hot working equipment, specifically a method for demolding large end caps during stamping. Background Technology

[0002] End caps are core components of pressure vessels used in industries such as nuclear power and petrochemicals. End caps can be manufactured using processes such as welding, extrusion forging, and stamping. However, within the limits of permissible shape and size, stamping offers advantages in reducing the gross-to-net-weight ratio of forgings and improving the consistency of performance across different parts of the forging.

[0003] When large free forging presses use stamping processes to produce end caps without ball defects or with straight edges, the forging punch is difficult to remove after forming. Since the free forging press equipment does not have a demolding linkage mechanism, the mold must be disassembled and demolded on a special platform, which seriously affects the production rhythm and is not conducive to actual production.

[0004] If the mold clearance is increased or the draft angle is increased to prevent mold jamming, it will be detrimental to the shape control of the forging and will increase the weight of the forging, thus increasing the cost. Summary of the Invention

[0005] The purpose of this invention is to provide a method for demolding large end caps during stamping, which can solve the technical problem of the inability to deal with the situation in a timely manner when the forging of end caps without ball defects or with straight edges is caused by the punch sticking to the die after forming.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A method for demolding a large end cap during stamping involves using a demolding fixture. The demolding fixture includes a clamping part, a forked structure at one end of the clamping part, and two extension parts at the ends of the two forked arms of the forked structure. One end of each extension part is fixedly connected to the end of the forked arm of the forked structure, and the other end extends away from the clamping part. The length direction of the two extension parts is parallel to the axis of the clamping part and symmetrically distributed along the axis of the clamping part.

[0008] The demolding method includes the following steps.

[0009] Step 1: Clamp the clamping part of the demolding fixture onto the manipulator of the forging press. The manipulator can move the clamping fixture and make it rotate around the axis of the clamping part.

[0010] Step 2: After the end cap is stamped, lift the punch upwards. If the end cap cannot be naturally removed from the punch, use the manipulator to move the demolding fixture to the two extension parts located on both sides of the punch, so that the two extension parts correspond to the end faces of the opening end of the end cap located on both sides of the punch.

[0011] Step 3: Control the demolding fixture to move using the manipulator, and apply pressure to the end face of the head opening using the extension to separate the head from the punch.

[0012] Furthermore, the clamping part has a cylindrical structure, the forked structure is semi-circular, the bottom of the forked structure is fixedly connected to one end of the clamping part, and the two forked arms of the forked structure are symmetrically arranged along the axis of the clamping part.

[0013] Furthermore, the clamping part, the forked structure, and the extension part are forged into a single piece. The forked structure and the extension part are obtained by removing the excess part in the middle through gas cutting of the integral forging.

[0014] Furthermore, in step three, the demolding fixture is moved so that the two extensions contact the end faces of the head openings on both sides of the punch. The demolding fixture is moved up and down, and pressure is applied to the end faces of the head openings on both sides simultaneously by the two extensions, so that the head separates from the punch.

[0015] Furthermore, in step three, the demolding fixture is moved to maintain a set distance between the extension and the end face of the head opening. The demolding fixture is then rotated around the axis of the clamping part by the manipulator, so that one extension of the demolding fixture contacts the corresponding end face of the head opening and applies pressure. The demolding fixture is then rotated in the opposite direction, so that the other extension of the demolding fixture contacts the corresponding end face of the head opening and applies pressure. The demolding fixture is rotated back and forth, and the two extensions alternately apply pressure to both sides of the end face of the head opening, so that the head separates from the punch.

[0016] Furthermore, the rapid reciprocating rotation of the demolding fixture generates an impact force when the extension contacts the corresponding end face of the head opening, further improving the demolding effect.

[0017] Furthermore, in step one, in order to improve the timeliness of demolding and prevent the thermal expansion and contraction of the end cap from causing further demolding difficulties, the manipulator clamps the demolding fixture in advance before the stamping operation begins.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects: 1. The stamping demolding method of the present invention overcomes the drawback of free forging press forging without a pull-down cylinder to release the upper die, and realizes demolding immediately; 2. By using the method in this invention to achieve effective demolding, the amount of machining required for the end cap can be reduced, the integrity of the metal flow lines can be preserved, and material costs can be reduced. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the demolding tooling in this invention.

[0020] Figure 2 This is a schematic diagram of the demolding method in Example 1 (the connection between the punch and the forging press is omitted).

[0021] Figure 3 This is a schematic diagram of the state in Embodiment 2 where the demolding tool is moved to a position where there is a certain distance between the extension and the opening end of the end cap.

[0022] Figure 4 This is a schematic diagram of the state in Embodiment 2 where the rotating demolding fixture causes the extension on the right side to contact the end face of the head opening and apply pressure.

[0023] Figure 5 This is a schematic diagram of the state in Embodiment 2 where the reverse rotation demolding fixture causes the extension on the left side to contact the end face of the head opening and apply pressure.

[0024] Figure descriptions: 1. Clamping part, 2. Forked structure, 21. Fork arm, 3. Extension part, 4. End cap, 5. Punch. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the features and performance of a large head stamping and demolding method of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Example 1 Please refer to the attached document. Figures 1-2 A method for demolding a large end cap during stamping, using a demolding fixture, which includes a clamping part 1, a forked structure 2 located at one end of the clamping part 1, and two extension parts 3 located at the ends of the two forked arms 21 of the forked structure 2.

[0027] The clamping part 1 is a cylindrical structure, and the forked structure 2 is a semi-circular arc. The bottom of the forked structure 2 is fixedly connected to one end of the clamping part 1, and the two forked arms 21 of the forked structure 2 are symmetrically arranged along the axis of the clamping part 1.

[0028] One end of the extension 3 is fixedly connected to the end of the fork arm 21 of the forked structure 2, and the other end extends away from the clamping part 1. The length direction of the two extensions 3 is parallel to the axis of the clamping part 1 and symmetrically distributed along the axis of the clamping part 1.

[0029] To ensure the rigidity of the demolding fixture during use, the clamping part 1, the forked structure 2, and the extension part 3 are forged into one piece. The forked structure 2 and the extension part 3 are obtained by removing the excess part in the middle through gas cutting of the one-piece forging.

[0030] The demolding method includes the following steps.

[0031] Step 1: Clamp the clamping portion 1 of the demolding tool onto the manipulator matched with the forging press. The manipulator can move the clamping tool and make the clamping tool rotate around the axis of the clamping portion 1. In order to improve demolding timeliness and prevent further demolding difficulties caused by thermal expansion and cold contraction of the head 4, the manipulator clamps the demolding tool in advance before the stamping operation starts.

[0032] Step 2: After the stamping of the head 4 is completed, lift the punch 5 upward. If the head 4 cannot naturally come off the punch 5, use the manipulator to move the demolding tool to make the two extension portions 3 located on both sides of the punch 5 respectively, so that the two extension portions 3 respectively correspond to the end faces of the parts of the open end of the head 4 on both sides of the punch 5.

[0033] Step 3: Control the movement of the demolding tool through the manipulator, and use the extension portions 3 to apply pressure to the end face of the open end of the head 4, so as to separate the head 4 from the punch 5.

[0034] Specifically, move the demolding tool to make the two extension portions 3 respectively contact the end faces of the open end of the head 4 on both sides of the punch 5, move the demolding tool up and down, and use the two extension portions 3 to simultaneously apply pressure to the end faces on both sides of the open end of the head 4, so as to separate the head 4 from the punch 5.

[0035] In specific implementation, taking a near-hemispherical head with a weight of 35 tons, a diameter of the head open end of 3670 mm, a wall thickness of 190 mm, and a straight section length of 100 mm as an example, the head 4 cannot naturally separate from the punch 5 after forming.

[0036] Use the manipulator to move the demolding tool until the two extension portions 3 are respectively in contact with the end faces of the parts of the open end of the head 4 on both sides of the punch 5, such as Figure 2 the state shown, continue to apply a downward force to the demolding tool. The downward pressure acts on the end faces of the parts of the open end of the head 4 on both sides of the punch 5 through the two extension portions 3, pressing the head 4 downward to realize demolding.

[0037] If demolding still cannot be achieved, the demolding tool can be moved upward for a certain distance and then moved downward, so that a certain impact force is generated when the extension portions 3 contact the head 4. This process can be repeated multiple times until demolding is completed.

[0038] Second Embodiment Different from the first embodiment, in step 3 of this embodiment, the demolding tool is moved to make a set distance remain between the extension portions 3 and the end face of the open end of the head 4. The manipulator controls the demolding tool to rotate around the axis of the clamping portion 1, so that one extension portion 3 of the demolding tool contacts the corresponding end face of the open end of the head 4 and applies pressure, then the demolding tool is rotated in the reverse direction, so that the other extension portion 3 of the demolding tool contacts the corresponding end face of the open end of the head 4 and applies pressure. The demolding tool is rotated in a reciprocating manner, and the two extension portions 3 are used to alternately apply pressure to both sides of the end face of the open end of the head 4, so as to separate the head 4 from the punch 5.

[0039] To further improve the demolding effect, the demolding fixture can be rotated back and forth quickly, so that when the extension 3 comes into contact with the opening end face of the corresponding end cap 4, an impact force is generated.

[0040] In specific implementation, taking a non-standard ellipsoidal head with a nozzle, weighing 15 tons, with an opening diameter of 2340 mm, a wall thickness of 180 mm, and a straight section length of 300 mm as an example, after the head 4 is formed, demolding is difficult due to its long straight edge length. Even using the method in Example 1 for demolding is still difficult.

[0041] like Figure 3 As shown, the demolding fixture is moved to a position where there is a certain distance between the extension 3 and the opening end of the head 4 using the manipulator.

[0042] First, rotate the demolding fixture around the axis of the clamping part 1, so that the extension part 3 on the right side of the demolding fixture moves downward and contacts the right end face of the opening end of the end cap 4 and applies pressure, such as Figure 4 The state shown.

[0043] Then rotate the demolding fixture in the opposite direction, causing the extension 3 on the left side of the demolding fixture to move downwards and contact the left end face of the opening end of the head 4, applying pressure, such as... Figure 5 The state shown.

[0044] The demolding fixture is rotated back and forth, and the extensions 3 on both sides are used to alternately apply the demolding force to both ends of the opening end of the head 4 until demolding is achieved.

[0045] If the demolding effect is still not ideal, the speed of the reciprocating demolding fixture can be increased so that when the extension 3 contacts the end face of the corresponding end cap 4 opening, an impact force is generated, thereby enhancing the demolding effect.

[0046] It should be noted that the parts not described in detail in this solution are all prior art. The above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for demolding large end caps formed by stamping, characterized in that: A demolding fixture is used, comprising a clamping part (1), a forked structure (2) at one end of the clamping part (1), and two extension parts (3) respectively located at the ends of the two fork arms (21) of the forked structure (2). One end of the extension part (3) is fixedly connected to the end of the fork arm (21) of the forked structure (2), and the other end extends away from the clamping part (1). The length direction of the two extension parts (3) is parallel to the axis of the clamping part (1) and symmetrically distributed along the axis of the clamping part (1). The demolding method includes the following steps: Step 1: Clamp the clamping part (1) of the demolding fixture onto the manipulator of the forging press. The manipulator can move the clamping fixture and make it rotate around the axis of the clamping part (1). Step 2: After the end cap (4) is stamped, lift the punch (5) upwards. If the end cap (4) cannot be naturally removed from the punch (5), use the manipulator to move the demolding fixture to the two extensions (3) located on both sides of the punch (5), so that the two extensions (3) correspond to the end faces of the opening end of the end cap (4) located on both sides of the punch (5). Step 3: Control the demolding fixture to move using the manipulator so that the extension part (3) and the end face of the opening end of the head (4) are at a set distance. Control the demolding fixture to rotate around the axis of the clamping part (1) so that one extension part (3) of the demolding fixture contacts the end face of the opening end of the corresponding head (4) and applies pressure. Rotate the demolding fixture in the opposite direction so that the other extension part (3) of the demolding fixture contacts the end face of the opening end of the corresponding head (4) and applies pressure. Rotate the demolding fixture back and forth so that the two extension parts (3) alternately apply pressure to both sides of the end face of the opening end of the head (4) to separate the head (4) from the punch (5).

2. The method for demolding a large end cap by stamping as described in claim 1, characterized in that: The clamping part (1) is a cylindrical structure, and the forked structure (2) is semi-circular. The bottom of the forked structure (2) is fixedly connected to one end of the clamping part (1). The two forked arms (21) of the forked structure (2) are symmetrically arranged along the axis of the clamping part (1).

3. The method for demolding a large end cap by stamping as described in claim 2, characterized in that: The clamping part (1), the forked structure (2) and the extension part (3) are forged integral structures. The forked structure (2) and the extension part (3) are obtained by removing the excess part in the middle by gas cutting of an integral forging.

4. The method for demolding a large end cap by stamping as described in claim 1, characterized in that: The demolding fixture is rotated rapidly back and forth, so that when the extension (3) comes into contact with the opening end face of the corresponding end cap (4), an impact force is generated, which further improves the demolding effect.

5. The method for demolding a large end cap through stamping as described in claim 1, characterized in that: In step one, in order to improve the timeliness of demolding and prevent the thermal expansion and contraction of the end cap (4) from causing further demolding difficulties, the manipulator clamps the demolding fixture in advance before the stamping operation begins.

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