Forming process and forming system of square plug

Abstract

The invention relates to the technical field of pipeline parts, in particular to a forming process and a forming system of a square plug. A forming process of a square plug comprises the following steps that A, upsetting is conducted, specifically, a straight pipe serves as a base body, the straight pipe comprises a material turning part and a straight pipe part which are connected, the material turning part is arranged at one end of the straight pipe part, upsetting is conducted on the material turning part, the height of the material turning part is reduced, and the cross section of the material turning part is increased; and B, pre-turning is conducted, specifically, the material turning part is punched, so that the material turning part is turned outwards from the end connected with the straight pipe part to the end away from the straight pipe part, and the material turning part is obliquely arranged relative to the straight pipe part. According to the forming process of the square plug, the precision and the qualified rate of the manufactured square plug are effectively improved, the overall dimension is accurate, the wall thickness is uniform, waste loss is small, and the problems that a square plug manufactured through an existing forming process of the square plug is poor in precision, low in qualified rate and large in material loss are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline parts, and in particular to a forming process and a forming system for a square plug. Background Art

[0002] The stainless steel square tube water distributor has the advantages of easy disassembly and assembly and good durability. The two side ports of this type of pipe fittings are precisely sealed with square plug components, which are connected to the threads of the mainstream pipeline. The wall thickness of the square plug component is 2.5mm, and it has a square boss and a stretched folded internal threaded structure. The square plug component belongs to the wall thickness hardware series parts.

[0003] At present, the existing forming process for the square plug of stainless steel square tube water distributor is as follows Figure 1 As shown, sheet metal is used for stamping operations. The sheet metal is first cut into a square shape, and then the process is carried out in the following order: S11, punching + cutting the shape; S12, turning the hole; S13, annealing; S14, square punching; S15, thread turning. The above process has the following problems: 1. Due to the use of stamping technology, sheet metal is used as raw material for stamping operations. The fluidity of thick stainless steel sheets during drawing is poor. In step S11, the edges and corners of the sheet metal are cut off by cutting the shape, making the shape of the sheet metal approximately circular, which is conducive to the punching and drawing. Therefore, the step of cutting the shape needs to be added, and the material loss during the cutting process is large; 2. Since the volume of the sheet metal is unchanged during the forming process, the actual punching height is difficult to meet the requirements of the drawing; 3. When the stainless steel sheet metal is punched, the straight wall will inevitably rebound. The straight pipe section after punching will become thinner and the diameter will decrease near the port position, making the straight pipe section after punching the hole as a whole in the shape of a tapered trumpet, which increases the difficulty of subsequent thread cutting in the straight pipe section; 4. Since the straight sheet metal needs to be stretched to a straight cylindrical shape, the material crystal is violently shaped and hardened easily. It is necessary to add an annealing step to release stress before subsequent operations can be carried out. Therefore, the existing above production process has obvious defects, large material loss, poor precision of the square plug produced, and low pass rate. Summary of the Invention

[0004] In response to the problems raised in the background technology, the purpose of the present invention is to propose a forming process for square plugs, which effectively improves the precision and pass rate of the square plugs produced, with accurate external dimensions, uniform wall thickness, and less waste loss, solving the problems of poor precision, low pass rate and large material loss of square plugs produced by the existing square plug forming process.

[0005] Another object of the present invention is to provide a molding system applied to the above molding process, which has high production efficiency.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A forming process for a square plug, comprising the following steps:

[0008] Step A, upsetting: Taking a straight pipe as the base body, the straight pipe includes a material turning part and a straight pipe part connected to each other, the material turning part is arranged at one end of the straight pipe part, upsetting the material turning part to reduce the height of the material turning part and increase the cross-section;

[0009] Step B, pre-turning: Stamping the material turning part to turn the material turning part outwards from the end connected to the straight pipe part to the end far away from the straight pipe part, and the material turning part is arranged obliquely relative to the straight pipe part, and the included angle between the material turning part and the straight pipe part is an acute angle;

[0010] Step C, flattening: Stamping the material turning part to make the included angle between the material turning part and the straight pipe part 90°;

[0011] Step D, square blanking: Blanking the material turning part to cut the material turning part into a square shape;

[0012] Step E, threading and flat end facing: Cutting threads on the inner wall of the straight pipe part, and cutting the end face of the material turning part far away from the straight pipe part into a flat surface.

[0013] Furthermore, in the step B, after stamping the material turning part, the included angle between the material turning part and the straight pipe part is 45°.

[0014] A forming system for a square plug, applied to the forming process of the square plug, the forming system includes a multi-station die and a threading and flat end facing device;

[0015] The multi-station die is sequentially provided with an upsetting station, a pre-turning station, a flattening station and a square blanking station along the forming sequence, and the multi-station die is used to sequentially perform the steps of upsetting, pre-turning, flattening and square blanking on the straight pipe;

[0016] The threading and flat end facing device is arranged downstream of the multi-station die, and the threading and flat end facing device is used to cut threads on the inner wall of the straight pipe part and cut the end face of the material turning part far away from the straight pipe part into a flat surface.

[0017] Furthermore, the forming system further includes:

[0018] A loading manipulator, arranged upstream of the upsetting station, for loading the straight pipe to the upsetting station;

[0019] A first material transfer manipulator, arranged between the upsetting station and the pre-turning station, for moving the workpiece that has completed the upsetting step at the upsetting station to the pre-turning station;

[0020] The second transfer manipulator is arranged between the pre-flipping station and the flattening station and is used to move the workpiece that has completed the pre-flipping step at the pre-flipping station to the flattening station;

[0021] The third transfer manipulator is arranged between the flattening station and the square blanking station, and the third transfer manipulator is used to move the workpiece that has completed the flattening step at the flattening station to the square blanking station.

[0022] Furthermore, the multi-station die includes an upper die assembly and a lower die assembly. The upper die assembly includes an upper die base and a first punch unit, a second punch unit, a third punch unit, and a fourth punch unit that are sequentially arranged at the bottom of the upper die base along the forming sequence;

[0023] The lower die assembly includes a lower die base and a first concave template, a second concave template, a third concave template, and a fourth concave template that are sequentially and fixedly arranged on the lower die base along the forming sequence;

[0024] The lower die assembly further includes a lower supporting plate and a first supporting and ejecting unit, a second supporting and ejecting unit, a third supporting and ejecting unit, and a blanking unit that are sequentially and fixedly arranged on the lower supporting plate along the forming sequence; the lower supporting plate is arranged below the lower die base. The first supporting and ejecting unit, the second supporting and ejecting unit, and the third supporting and ejecting unit are used to support the workpiece to be formed and eject the formed workpiece, and the blanking unit is used for the workpiece that has completed the square blanking to drop;

[0025] The first punch unit, the first concave template, and the first supporting and ejecting unit are correspondingly arranged and located at the upsetting station. The first punch unit is used to cooperate with the first concave template when the die is closed to perform the upsetting step on the straight pipe;

[0026] The second punch unit, the second concave template, and the second supporting and ejecting unit are correspondingly arranged and located at the pre-flipping station. The second punch unit is used to cooperate with the second concave template when the die is closed to perform the pre-flipping step on the workpiece;

[0027] The third punch unit, the third concave template, and the third supporting and ejecting unit are correspondingly arranged and located at the flattening station. The third punch unit is used to cooperate with the third concave template when the die is closed to perform the flattening step on the workpiece;

[0028] The fourth punch unit, the fourth concave template, and the blanking unit are correspondingly arranged and located at the square blanking station. The fourth punch unit is used to cooperate with the fourth concave template when the die is closed to perform the square blanking step on the workpiece.

[0029] Further elaboration is as follows. The first punch unit includes a first punch, a first upper pressing block, a first stripper plate, a first elastic member, and a second elastic member. The first punch is fixedly arranged at the bottom of the upper die base. The first upper pressing block is arranged to move in the vertical direction inside the first punch through the first elastic member. The end of the first upper pressing block away from the upper die base protrudes from the first punch. The first stripper plate is arranged to move in the vertical direction on the upper die base through the second elastic member.

[0030] The first supporting and ejecting unit includes a third elastic member, a first supporting block, and a first ejector rod. One end of the third elastic member is fixedly connected to the lower supporting plate, the other end of the third elastic member is connected to the bottom of the first supporting block, and the top of the first supporting block is connected to the first ejector rod.

[0031] The lower die assembly further includes a first lower backing plate, which is fixedly arranged between the first concave die plate and the lower die base. The lower die base and the first lower backing plate are respectively provided with a first through hole in the vertical direction. The first concave die plate is provided with a first material supporting channel in the vertical direction. The first ejector rod passes through the first through hole of the lower die base and the first through hole of the first lower backing plate and then inserts into the first material supporting channel. The first ejector rod is provided with a first rod head for abutting against the upper surface of the first lower backing plate.

[0032] The first upper pressing block and the first ejector rod are arranged corresponding to each other. The first stripper plate and the first concave die plate are arranged corresponding to each other. A upsetting avoidance opening is formed on the top wall surface of the first material supporting channel, and a first forming step cooperating with the upsetting avoidance opening is arranged at the bottom of the first punch.

[0033] Further elaboration is as follows. The second punch unit includes a second punch, a second upper pressing block, a second stripper plate, a fourth elastic member, and a fifth elastic member. The second punch is fixedly arranged at the bottom of the upper die base. The second upper pressing block is arranged to move in the vertical direction inside the second punch through the fourth elastic member. The end of the second upper pressing block away from the upper die base protrudes from the second punch. The second stripper plate is arranged to move in the vertical direction on the upper die base through the fifth elastic member.

[0034] The second supporting and ejecting unit includes a sixth elastic member, a second supporting block, and a second ejector rod. One end of the sixth elastic member is fixedly connected to the lower supporting plate, the other end of the sixth elastic member is connected to the bottom of the second supporting block, and the top of the second supporting block is connected to the second ejector rod.

[0035] The lower die assembly further includes a second lower backing plate, which is fixedly arranged between the second concave template and the lower die base. The lower die base and the second lower backing plate are respectively provided with second through holes penetrating in the up-down direction. The second concave template is provided with a second material supporting channel penetrating in the up-down direction. The second ejector rod passes through the second through hole of the lower die base and the second through hole of the second lower backing plate and then inserts into the second material supporting channel. The second ejector rod is provided with a second rod head for abutting against the upper surface of the second lower backing plate;

[0036] The second upper pressing block is arranged corresponding to the second ejector rod, the second stripper plate is arranged corresponding to the second concave template, and the bottom of the second punch is provided with a pre-bending forming inclined surface.

[0037] Further description, the third punch unit includes a third punch, a third upper pressing block, a third stripper plate, a seventh elastic member and an eighth elastic member. The third punch is fixedly arranged at the bottom of the upper die base. The third upper pressing block is movably arranged in the third punch in the up-down direction through the seventh elastic member. The end of the third upper pressing block away from the upper die base protrudes out of the third punch. The third stripper plate is movably arranged on the upper die base in the up-down direction through the eighth elastic member;

[0038] The third supporting and ejecting unit includes a ninth elastic member, a third supporting block and a third ejector rod. One end of the ninth elastic member is fixedly connected with the lower supporting plate, the other end of the ninth elastic member is connected with the bottom of the third supporting block, and the top of the third supporting block is connected with the third ejector rod;

[0039] The lower die assembly further includes a third lower backing plate, which is fixedly arranged between the third concave template and the lower die base. The lower die base and the third lower backing plate are respectively provided with third through holes penetrating in the up-down direction. The third concave template is provided with a third material supporting channel penetrating in the up-down direction. The third ejector rod passes through the third through hole of the lower die base and the third through hole of the third lower backing plate and then inserts into the third material supporting channel. The third ejector rod is provided with a third rod head for abutting against the upper surface of the third lower backing plate;

[0040] The third upper pressing block is arranged corresponding to the third ejector rod, the third stripper plate is arranged corresponding to the third concave template, and the bottom of the third punch is provided with a second forming step, and the second forming step is in a right-angled shape.

[0041] Further description, the fourth punch unit includes a fourth punch, a fourth stripper plate and a tenth elastic member. The fourth punch is fixedly arranged at the bottom of the upper die base. The fourth stripper plate is movably arranged on the upper die base in the up-down direction through the tenth elastic member;

[0042] The blanking unit includes a blanking plate which is arranged to slope downwards from one end close to the third supporting and ejecting unit to the other end far from the third supporting and ejecting unit;

[0043] The lower die assembly further includes a fourth lower backing plate which is fixedly arranged between the fourth concave template and the lower die base. The fourth concave template, the fourth lower backing plate and the lower die base are respectively provided with blanking channels for the workpieces after square blanking to fall. The blanking channels are arranged corresponding to the fourth punch. The fourth stripper plate is arranged corresponding to the fourth concave template. The blanking plate is arranged below the blanking channels.

[0044] Furthermore, the upper die assembly further includes a plurality of upper backing plates and a plurality of fixing plates. The upper backing plates are respectively arranged between the upper die base and the first punch unit, between the upper die base and the second punch unit, between the upper die base and the third punch unit, and between the upper die base and the fourth punch unit;

[0045] The fixing plates are arranged corresponding to the upper backing plates one by one. The fixing plates are arranged on the lower end faces of the corresponding upper backing plates. The first punch unit, the second punch unit, the third punch unit and the fourth punch unit are respectively arranged on the corresponding fixing plates;

[0046] The lower die assembly further includes a plurality of feet which are fixedly connected between the lower die base and the lower supporting plate.

[0047] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0048] By optimizing the process method with a sheet metal as the base, using a straight pipe as the base for forming, and through the step-by-step forming process of "upsetting + pre-turning + flattening", the forming stability of the turned part of the square plug is effectively improved, the severe deformation and cracking at the outer edge of the platform are avoided, the generation of stainless steel hardening phenomenon is avoided, the accuracy and qualified rate of the obtained square plug are effectively improved, the external dimensions are accurate, the wall thickness is uniform, and the waste loss is small, solving the problems of poor accuracy, low qualified rate and large material loss of the square plug obtained by the existing forming process of the square plug. Description of the Drawings

[0049] Figure 1 is a schematic flow chart of the existing forming process of the square plug.

[0050] Figure 2 is a schematic flow chart of the forming process of the square plug of the present invention.

[0051] Figure 3 is a cross-sectional view after upsetting of the straight pipe used in the forming process of the square plug in an embodiment of the present invention.

[0052] Figure 4 It is a cross-sectional view after pre-bending of a straight pipe used in the forming process of the square plug of an embodiment of the present invention.

[0053] Figure 5 It is a schematic structural diagram of a multi-station mold of a forming system of an embodiment of the present invention in an open mold state.

[0054] Figure 6 It is a schematic structural diagram of a multi-station mold of a forming system of an embodiment of the present invention in a closed mold state.

[0055] Figure 7 It is a schematic structural diagram of the upper die assembly and the lower die assembly of a multi-station mold of a forming system of an embodiment of the present invention at the upsetting station.

[0056] Figure 8 It is a schematic structural diagram of the upper die assembly and the lower die assembly of a multi-station mold of a forming system of an embodiment of the present invention at the pre-bending station.

[0057] Figure 9 It is a schematic structural diagram of the upper die assembly and the lower die assembly of a multi-station mold of a forming system of an embodiment of the present invention at the flattening station.

[0058] Figure 10 It is a schematic structural diagram of the upper die assembly and the lower die assembly of a multi-station mold of a forming system of an embodiment of the present invention at the square blanking station.

[0059] In the attached drawings: 1 - multi-station die, 101 - upsetting station, 102 - pre-flipping station, 103 - flattening station, 104 - square blanking station, 2 - upper die assembly, 21 - upper die base, 22 - first punch unit, 221 - first punch, 2211 - first forming step, 222 - first upper pressure block, 223 - first stripper plate, 224 - first elastic member, 225 - second elastic member, 23 - second punch unit, 231 - second punch, 2311 - pre-flipping forming inclined surface, 2312 - vertical forming surface, 232 - second upper pressure block, 233 - second stripper plate, 234 - fourth elastic member, 235 - fifth elastic member, 24 - third punch unit, 241 - third punch, 2411 - second forming step, 242 - third upper pressure block, 243 - third stripper plate, 244 - seventh elastic member, 245 - eighth elastic member, 25 - fourth punch unit, 251 - fourth punch, 252 - fourth stripper plate, 253 - tenth elastic member, 26 - upper backing plate, 27 - fixing plate, 3 - lower die assembly, 30 - lower die base, 31 - first concave template, 311 - first material supporting channel, 3111 - upsetting avoidance opening, 32 - second concave template, 321 - second material supporting channel, 33 - third concave template, 331 - third material supporting channel, 34 - fourth concave template, 35 - lower supporting plate, 36 - first supporting and ejecting unit, 361 - third elastic member, 362 - first supporting block, 363 - first ejector rod, 3631 - first rod head, 37 - second supporting and ejecting unit, 371 - sixth elastic member, 372 - second supporting block, 373 - second ejector rod, 3731 - second rod head, 38 - third supporting and ejecting unit, 381 - ninth elastic member, 382 - third supporting block, 383 - third ejector rod, 3831 - third rod head, 39 - blanking unit, 391 - blanking plate, 301 - first lower backing plate, 3011 - first through hole, 302 - second lower backing plate, 3021 - second through hole, 303 - third lower backing plate, 3031 - third through hole, 304 - fourth lower backing plate, 3041 - blanking channel, 305 - pad foot, 11 - straight pipe, 111 - material flipping part, 112 - straight pipe part. Detailed implementation manners

[0060] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the attached drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the attached drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0061] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features, which are used to distinguish and describe features without order or importance.

[0062] As Figures 1 to 4 shown, a forming process for a square plug, which is used to produce a square plug, includes the following steps:

[0063] Step A: Upsetting: Using the straight pipe 11 as the base body, the straight pipe 11 includes a turning part 111 and a straight pipe part 112 that are connected. The straight pipe 11 can specifically be a stainless steel straight pipe 11. The turning part 111 is arranged at one end of the straight pipe part 112. Upset the turning part 111 so that the height of the turning part 111 decreases and the cross-section increases.

[0064] Step B: Pre-turning: Stamp the turning part 111 so that the turning part 111 turns outwards from the end connected to the straight pipe part 112 to the end far from the straight pipe part 112, and the turning part 111 is inclined with respect to the straight pipe part 112. The included angle between the turning part 111 and the straight pipe part 112 is an acute angle.

[0065] Step C: Flattening: Stamp the turning part 111 so that the included angle between the turning part 111 and the straight pipe part 112 becomes 90°.

[0066] Step D: Square blanking: Blank the turning part 111 to cut the turning part 111 into a square shape, that is, cut it into a square shape.

[0067] Step E: Thread cutting and end face flattening: Cut threads on the inner wall of the straight pipe part 112 and cut the end face of the turning part 111 far from the straight pipe part 112 into a flat surface.

[0068] Currently, the existing forming process for the square plug of the stainless steel square pipe water divider is as Figure 1As shown in the figure, it is made by stamping operation using sheet metal. First, the sheet metal is cut into a square, and then the following technological sequence is carried out: S11, punching + cutting the outer shape; S12, flanging; S13, annealing; S14, square blanking; S15, threading. The above process has the following problems: 1. Since the stamping process is adopted and sheet metal is used as the raw material for stamping operation, the drawing fluidity of stainless steel sheet with a relatively thick thickness is poor. In the S11 step, by cutting the outer shape, the corners of the sheet metal are cut off, making the outer shape of the sheet metal approximately circular, which is beneficial for flanging and pulling the material. Therefore, the step of cutting the outer shape needs to be added, and the material loss is relatively large during the process of cutting the outer shape; 2. Since the volume of the sheet metal remains unchanged during the forming process, it is difficult for the actual flanging height to meet the requirements of the drawing; 3. When the stainless steel sheet is flanged, there will inevitably be a springback phenomenon in the straight wall. The straight pipe section after flanging will become thinner and the diameter will decrease near the port position, making the overall shape of the straight pipe section after flanging a tapered bell mouth shape, increasing the difficulty of threading in the straight pipe section in the subsequent process; 4. Since the flat sheet metal needs to be stretched into a straight tube shape, the material crystal undergoes severe plastic deformation, and hardening is likely to occur. An annealing step is required to release the stress before subsequent operations can be carried out. Therefore, the obvious defects of the existing above production process are large material loss, poor precision of the square plug produced, and low qualified rate.

[0069] The forming process of the present invention takes the straight pipe 11 as the base body. As Figure 2 shown in the figure, the technological steps are as follows: S21, upsetting. First, upset the flanging part 111 of the straight pipe 11; S22, pre-flanging. Stamp the flanging part 111 so that the flanging part 111 is inclined relative to the straight pipe part 112, and the included angle between the flanging part 111 and the straight pipe part 112 is an acute angle; S23, flattening. Stamp the flanging part 111 so that the included angle between the flanging part 111 and the straight pipe part 112 is 90°; S24, square blanking. Cut the flanging part 111 into a square; S25, threading and flattening the end face. Cut threads on the inner wall of the straight pipe part 112, and cut the end face of the flanging part 111 away from the straight pipe part 112 into a flat surface.

[0070] Since the forming process of the present invention uses the straight pipe 11 as the base body, after upsetting, the angle between the turning part 111 and the straight pipe part 112 is made acute by pre-turning first, then the turning part 111 is flattened to obtain a horizontal turning part 111, and then the horizontal turning part 111 is square blanked. There is no need for the step of punching a hole, which can avoid severe plastic deformation of the pipe fitting. Among them, the distributed process of "upsetting + pre-turning + flattening", with pre-turning first and then flattening, can improve the forming stability of the turning part 111 of the straight pipe 11 processed into a horizontal platform, avoid severe deformation and cracking at the outer edge of the horizontal turning part 111 caused by directly flattening, and avoid the generation of hardening phenomenon, resulting in a high service life of the mold and effectively improving the accuracy and qualification rate of the square plug obtained in production. In addition, since the process step of cutting the outer shape of the sheet material (a large amount of sheet material needs to be cut when cutting the outer shape) is reduced, using the straight pipe 11 as the raw material, the material utilization rate of the pipe fitting is high, the waste loss is small, and the situation where the straight section becomes flared after punching a hole in the existing process will not occur. The deformation of the inner wall and outer wall of the straight pipe 11 is small, the outer dimension is accurate, resulting in high threading accuracy, and the accuracy and qualification rate of the manufactured square plug are high.

[0071] Furthermore, to turn the port of the 11 straight pipes into a vertical plane (i.e., form a platform perpendicular to the straight pipes 11), the common process is spin forming, whose processing efficiency is much lower than the forming process of the present invention. Limited by the characteristics of stainless steel materials, when turning the surface, it is a technical difficulty for such products to turn a sufficiently wide flat surface and ensure that the flat surface does not crack, and at the same time ensure that the flat surface has a uniform wall thickness. For the threaded connection of the waterway pipe fittings of the water separator, the perpendicularity requirement for screwing with the waterway pipe is high. When the thread profile of the plug is skewed, it will cause the pipeline to fail to be screwed or the waterway to bend and twist after being connected in series, resulting in poor waterway sealing and affecting the construction progress. At the same time, the square plug is precisely seam-welded with the water inlet pipe nozzle, and the weld seam has high sealing requirements and does not allow defects such as incomplete penetration, air holes, and cracks. Only through precise mating processes can a perfect water separator main pipe fitting be produced. The square plug prepared by the forming process of the present invention has its straight pipe part 112 perpendicular to the turned part 111, which can meet the stability of the internal thread of the workpiece screwing with the waterway pipe fitting. The overall wall thickness can be made to be a uniform thickness of 2.5 mm, and the thickness of the turned part 111 and the straight pipe part 112 is also a uniform wall thickness of 2.5 mm to ensure the tightness of the weld seam during the production of the pipe fitting and avoid local burn-through and bead formation caused by uneven wall thickness, which may further lead to welding defects such as incomplete penetration, air holes, and cracks. In reality, there is a thinning phenomenon when the pipe orifice is turned outwards. The larger the turned-out diameter, the more the thinning amount. The following further explains the forming process of the present invention. Before stamping and turning outwards with the straight pipe 11 as the base, a upsetting step is added, that is, locally thickening the convex platform area to be turned outwards. For example, the wall thickness of the turned part 111 is upset from 2.5 mm to 3 mm. After the pre-turning and flattening steps (i.e., turning out the turned part 111 so that the turned part 111 becomes a convex platform relative to the straight pipe part 112), the wall thickness of the outer edge of the turned part 111 changes in the range of 2.6 mm to 2.9 mm from the outside to the inside (i.e., from the end far from the straight pipe part 112 to the end close to the straight pipe part 112). Through the upsetting step, after pre-turning and flattening, the minimum wall thickness of this area of the turned part 111 is still greater than the required wall thickness of the product. After square blanking, through the step of threading and flattening the cross-section, the end face of the turned part 111 far from the straight pipe part 112 is cut into a flat surface. For example, the turned part 111 is cut into a wall thickness of 2.5 mm. After threading the inner wall of the straight pipe part 112, the internal thread of the obtained square plug has high perpendicularity, and the wall thickness at the convex platform position (i.e., the turned part 111 after cutting) is uniform and accurate.

[0072] In the present invention, the process of "upsetting + pre - turning" is adopted. During upsetting, it is equivalent to pushing the material towards the area of the turning part 111 (i.e., the area that needs to be turned outwards and flattened). During the process of turning outwards, the wall thickness of the turning part 111 will become thinner and wider. When the area of the turning part 111 is being flattened, most of the area is flattened as a whole under the positive pressure of the punch during stamping, which slows down the phenomenon of the turning part 111 becoming thinner again, effectively improving the forming stability of the boss of the square plug (i.e., the turned - out part 111 after flattening), effectively avoiding the severe deformation and cracking of the outer edge of the turning part 111 after flattening, and at the same time avoiding the generation of hardening phenomenon. Using the straight pipe 11 as the base for pre - turning and flattening, the waste ratio is small, the material utilization rate is high, the dimensions are accurate, and the tooth profile accuracy of threading is high. [[ID=I]]

[0073] The present invention optimizes the process method with a sheet material (specifically a steel plate) as the base, uses the straight pipe 11 (specifically a stainless - steel straight pipe 11) as the base for forming, and through the step - by - step forming process of "upsetting + pre - turning + flattening", effectively improves the forming stability of the turning part 111 (i.e., the boss of the plug) of the square plug, avoids the severe deformation and cracking of the outer edge of the platform, avoids the generation of stainless - steel hardening phenomenon, effectively improves the accuracy and qualification rate of the obtained square plug, with accurate external dimensions, uniform wall thickness, and less waste loss, solving the problems of poor accuracy, low qualification rate, and large material loss of the square plug obtained by the existing forming process of the square plug.

[0074] Furthermore, in step A, first cut the straight pipe 11 to the required length, and then upset the turning part 111.

[0075] Furthermore, in step B, after stamping the turning part 111, the included angle between the turning part 111 and the straight - pipe part 112 is 45°.

[0076] After pre - turning, the included angle between the turning part 111 and the straight - pipe part 112 is 45°. Pre - turning the turning part 111 by an angle of 45° can avoid the severe deformation and cracking of the turning part 111 during the flattening process due to direct flattening.

[0077] As Figures 5 to 10 shown, a forming system for a square plug is applied to the forming process of the square plug. The forming system includes a multi - station die 1 and a threading and flat - end - face equipment;

[0078] The multi - station die 1 is sequentially provided with an upsetting station 101, a pre - turning station 102, a flattening station 103, and a square blanking station 104 along the forming sequence. The multi - station die 1 is used to sequentially perform the steps of upsetting, pre - turning, flattening, and square blanking on the straight pipe 11;

[0079] The threading and flat-end facing device is arranged downstream of the multi-station die 1 and is used for cutting threads on the inner wall of the straight pipe portion 112 and cutting the end face of the turning portion 111 away from the straight pipe portion 112 into a flat surface.

[0080] By arranging the multi-station die 1 and setting the steps of upsetting, pre-turning, flattening, and square blanking in the multi-station die 1, multiple forming steps can be simultaneously carried out on multiple workpieces in the same die, resulting in high forming efficiency and rapid forming.

[0081] Specifically, the threading and flat-end facing device can be an existing numerical control lathe. By setting the parameters of the numerical control lathe for automatic tool change, the steps of threading and flat-end facing are completed in the threading and flat-end facing device.

[0082] Furthermore, the forming system further includes:

[0083] A loading manipulator, arranged upstream of the upsetting station 101, for loading the straight pipe 11 onto the upsetting station 101;

[0084] A first transfer manipulator, arranged between the upsetting station 101 and the pre-turning station 102, for moving the workpiece that has completed the upsetting step at the upsetting station 101 to the pre-turning station 102;

[0085] A second transfer manipulator, arranged between the pre-turning station 102 and the flattening station 103, for moving the workpiece that has completed the pre-turning step at the pre-turning station 102 to the flattening station 103;

[0086] A third transfer manipulator, arranged between the flattening station 103 and the square blanking station 104, and the third transfer manipulator is used for moving the workpiece that has completed the flattening step at the flattening station 103 to the square blanking station 104.

[0087] By arranging the loading manipulator, the first transfer manipulator, the second transfer manipulator, and the third transfer manipulator, multiple manipulators can synchronously clamp the workpiece for step-by-step movement, realizing the automated operations of upsetting, pre-turning, flattening, and square blanking, and effectively improving the production efficiency.

[0088] Specifically, the loading manipulator, the first transfer manipulator, the second transfer manipulator, and the third transfer manipulator adopt the existing manipulator structures that can clamp the workpiece.

[0089] To further illustrate, the multi-station die 1 includes an upper die assembly 2 and a lower die assembly 3. The upper die assembly 2 includes an upper die base 21, and a first punch unit 22, a second punch unit 23, a third punch unit 24, and a fourth punch unit 25 that are sequentially arranged at the bottom of the upper die base 21 along the forming sequence.

[0090] The lower die assembly 3 includes a lower die base 30, and a first concave template 31, a second concave template 32, a third concave template 33, and a fourth concave template 34 that are sequentially and fixedly arranged on the lower die base 30 along the forming sequence.

[0091] The lower die assembly 3 further includes a lower carrier plate 35, and a first supporting and ejecting unit 36, a second supporting and ejecting unit 37, a third supporting and ejecting unit 38, and a blanking unit 39 that are sequentially and fixedly arranged on the lower carrier plate 35 along the forming sequence. The lower carrier plate 35 is arranged below the lower die base 30. The first supporting and ejecting unit 36, the second supporting and ejecting unit 37, and the third supporting and ejecting unit 38 are used to support the workpieces to be formed and eject the formed workpieces, and the blanking unit 39 is used for the blanking of the workpieces that have completed square blanking.

[0092] The first punch unit 22, the first concave template 31, and the first supporting and ejecting unit 36 are correspondingly arranged and located at the upsetting station 101. The first punch unit 22 is used to cooperate with the first concave template 31 to upset the straight pipe 11 when the die is closed.

[0093] The second punch unit 23, the second concave template 32, and the second supporting and ejecting unit 37 are correspondingly arranged and located at the pre-folding station 102. The second punch unit 23 is used to cooperate with the second concave template 32 to pre-fold the workpiece when the die is closed.

[0094] The third punch unit 24, the third concave template 33, and the third supporting and ejecting unit 38 are correspondingly arranged and located at the flattening station 103. The third punch unit 24 is used to cooperate with the third concave template 33 to flatten the workpiece when the die is closed.

[0095] The fourth punch unit 25, the fourth concave template 34, and the blanking unit 39 are correspondingly arranged and located at the square blanking station 104. The fourth punch unit 25 is used to cooperate with the fourth concave template 34 to perform square blanking on the workpiece when the die is closed.

[0096] By correspondingly arranging the first punch unit 22, the first female die plate 31 and the first supporting and ejecting unit 36, correspondingly arranging the second punch unit 23, the second female die plate 32 and the second supporting and ejecting unit 37, correspondingly arranging the third punch unit 24, the third female die plate 33 and the third supporting and ejecting unit 38, and correspondingly arranging the fourth punch unit 25, the fourth female die plate 34 and the blanking unit 39, automatic operations of upsetting, pre-turning, patting flat and square blanking can be realized in the same multi-station die 1.

[0097] Furthermore, the first punch unit 22 includes a first punch 221, a first upper pressing block 222, a first stripper plate 223, a first elastic member 224 and a second elastic member 225. The first punch 221 is fixedly arranged at the bottom of the upper die base 21. The first upper pressing block 222 is movably arranged in the first punch 221 in the vertical direction through the first elastic member 224. The end of the first upper pressing block 222 away from the upper die base 21 protrudes from the first punch 221. The first stripper plate 223 is movably arranged on the upper die base 21 in the vertical direction through the second elastic member 225.

[0098] The first supporting and ejecting unit 36 includes a third elastic member 361, a first supporting block 362 and a first ejector rod 363. One end of the third elastic member 361 is fixedly connected to the lower supporting plate 35, the other end of the third elastic member 361 is connected to the bottom of the first supporting block 362, and the top of the first supporting block 362 is connected to the first ejector rod 363.

[0099] The lower die assembly 3 further includes a first lower backing plate 301. The first lower backing plate 301 is fixedly arranged between the first female die plate 31 and the lower die base 30. The lower die base 30 and the first lower backing plate 301 are respectively provided with a first through hole 3011 in the vertical direction. The first female die plate 31 is provided with a first stock supporting channel 311 in the vertical direction. The first ejector rod 363 passes through the first through hole 3011 of the lower die base 30 and the first through hole 3011 of the first lower backing plate 301 and then inserts into the first stock supporting channel 311. The first ejector rod 363 is provided with a first rod head 3631 for abutting against the upper surface of the first lower backing plate 301.

[0100] The first upper pressing block 222 and the first ejector rod 363 are correspondingly arranged. The first stripper plate 223 and the first female die plate 31 are correspondingly arranged. The top wall surface of the first stock supporting channel 311 is provided with an upsetting avoidance opening 3111. The bottom of the first punch 221 is provided with a first forming step 2211 for cooperating with the upsetting avoidance opening 3111.

[0101] Place the straight pipe 11 into the upsetting station 101. When placing it, make the turning part 111 of the straight pipe 11 face the first punch unit 22. Close the mold to make the upper mold base 21 move downward. The first upper pressing block 222 abuts against the first ejector rod 363 and presses the first ejector rod 363 downward. The third elastic member 361 undergoes elastic deformation until the first rod head 3631 of the first ejector rod 363 fits against the first lower backing plate 301, causing the first ejector rod 363 to be in place statically (the first upper pressing block 222 presses the first ejector rod 363 in place, and the straight pipe 11 falls freely or is pressed by the first punch 221 to reach the end face of the first ejector rod 363 before being force-formed. The first ejector rod 363 is a force-receiving member); the upper mold base 21 continues to move downward, the first stripper plate 223 contacts the first concave template 31, and the second elastic member 225 begins to be compressed. In this section of the continuous downward movement interval, the first punch 221 begins to contact the straight pipe 11 and presses it down to the top surface of the first ejector rod 363; the upper mold base 21 continues to move downward, the second elastic member 225 continues to be compressed, and the first punch 221 upsets the turning part 111 of the straight pipe 11. After completing the upsetting step, open the mold. The upper mold base 21 moves upward, and the first stripper plate 223 pushes the workpiece downward away from the first punch 221 under the elastic action of the second elastic member 225, realizing the stripping of the workpiece from the first punch 221. After the first upper pressing block 222 disengages from the first ejector rod 363, the first ejector rod 363 moves upward under the elastic action of the third elastic member 361, pushing the workpiece upward to realize push-out and ejection, and pushing the top end of the workpiece out of the first material supporting channel 311.

[0102] Specifically, the upsetting avoidance opening 3111 cooperates with the first forming step 2211. The diameter of the upsetting avoidance opening 3111 is larger than the diameter of the first material supporting channel 311. The first forming step 2211 is in a right-angled shape. When the first punch 221 stamps on the straight pipe 11 for forming, the horizontal plane where the top end surface of the straight pipe 11 is located is below the horizontal plane where the top end surface of the first concave template 31 is located. The first forming step 2211 contacts the top end surface and the inner wall surface of the straight pipe 11. Under the action of the upsetting avoidance opening 3111, it is possible to reduce the height of the turning part 111 and increase the cross-section, and the inner wall of the straight pipe 11 is straight (that is, the inner diameter of the straight pipe 11 remains unchanged).

[0103] Furthermore, the first ejector rod 363 pushes out the workpiece, facilitating the grasping of the first transfer manipulator.

[0104] Furthermore, when the mold is closed, the bottom surface of the first stripper plate 223 contacts the surface of the first concave mold plate 31 without interfering with the workpiece. When the mold is opened, the first stripper plate 223 is pushed open under the elastic force of the second elastic member 225 to push the workpiece away from the first punch 221, so that the workpiece stays in the lower mold assembly 3, facilitating the operation of the first transfer manipulator.

[0105] Furthermore, the first elastic member 224 is a nitrogen spring, the second elastic member 225 is a spring, the third elastic member 361 is a polyurethane rubber, and the elastic force of the first elastic member 224 is much greater than the elastic force of the third elastic member 361, ensuring that the first upper pressing block 222 can press the first ejector rod 363 downward.

[0106] Furthermore, the second punch unit 23 includes a second punch 231, a second upper pressing block 232, a second stripper plate 233, a fourth elastic member 234, and a fifth elastic member 235. The second punch 231 is fixedly arranged at the bottom of the upper mold base 21. The second upper pressing block 232 is movably arranged in the second punch 231 in the vertical direction through the fourth elastic member 234. The end of the second upper pressing block 232 away from the upper mold base 21 protrudes from the second punch 231. The second stripper plate 233 is movably arranged in the upper mold base 21 in the vertical direction through the fifth elastic member 235;

[0107] The second supporting and ejecting unit 37 includes a sixth elastic member 371, a second supporting block 372, and a second ejector rod 373. One end of the sixth elastic member 371 is fixedly connected to the lower supporting plate 35, the other end of the sixth elastic member 371 is connected to the bottom of the second supporting block 372, and the top of the second supporting block 372 is connected to the second ejector rod 373;

[0108] The lower mold assembly 3 further includes a second lower backing plate 302. The second lower backing plate 302 is fixedly arranged between the second concave mold plate 32 and the lower mold base 30. The lower mold base 30 and the second lower backing plate 302 are respectively provided with second through holes 3021 in the vertical direction. The second concave mold plate 32 is provided with a second material supporting channel 321 in the vertical direction. The second ejector rod 373 passes through the second through hole 3021 of the lower mold base 30 and the second through hole 3021 of the second lower backing plate 302 and then inserts into the second material supporting channel 321. The second ejector rod 373 is provided with a second rod head 3731 for abutting against the upper surface of the second lower backing plate 302;

[0109] The second upper pressing block 232 and the second ejector rod 373 are arranged corresponding to each other. The second stripper plate 233 and the second concave mold plate 32 are arranged corresponding to each other. The bottom of the second punch 231 is provided with a pre - turning forming inclined surface 2311.

[0110] Place the workpiece into the pre - turning station 102, and when placing it, make the turning part 111 of the workpiece face the second punch unit 23. Close the mold to make the upper mold base 21 move downward. The second upper pressure block 232 abuts against the second ejector rod 373 and presses the second ejector rod 373 downward. The sixth elastic member 371 undergoes elastic deformation until the second rod head 3731 of the second ejector rod 373 fits against the second lower backing plate 302, so that the second ejector rod 373 stops in place (the second upper pressure block 232 presses the second ejector rod 373 in place. The workpiece falls freely or is pressed by the second punch 231 to reach the end face of the second ejector rod 373 before being force - formed. The second ejector rod 373 is a force - receiving member); the upper mold base 21 continues to move downward, the second stripper plate 233 contacts the second concave template 32, and the fifth elastic member 235 starts to be compressed. In this interval of continuous downward movement, the second punch 231 starts to contact the workpiece and presses it down to the top surface of the second ejector rod 373; the upper mold base 21 continues to move downward, the fifth elastic member 235 continues to be compressed, and the second punch 231 punches the turning part 111, causing the turning part 111 to turn outwards from the end connected to the straight pipe part 112 to the end far from the straight pipe part 112, and the turning part 111 is inclined relative to the straight pipe part 112. After completing the pre - turning step, open the mold. The upper mold base 21 moves upward, and the second stripper plate 233 pushes the workpiece downward away from the second punch 231 under the elastic action of the fifth elastic member 235, realizing the stripping of the workpiece from the second punch 231. After the second upper pressure block 232 disengages from the second ejector rod 373, the second ejector rod 373 moves upward under the elastic action of the sixth elastic member 371, pushing the workpiece upward to realize top - pushing and discharging, and pushing the top end of the workpiece out of the second material - supporting channel 321.

[0111] For further illustration, the thickness of the second rod head 3731 is greater than that of the first rod head 3631. During the previous upsetting step, the entire straight pipe 11 is located inside the first blank supporting channel 311. During the pre-turning step, the processing height of the workpiece is raised under the support of the second ejector rod 373, so that the turning part 111 is located above the second blank supporting channel 321, and the straight pipe part 112 is located inside the second blank supporting channel 321. Since the angle between the pre-turning forming inclined surface 2311 and the axis of the punch is 45°, when the second punch 231 presses on the workpiece for forming, the pre-turning forming inclined surface 2311 corresponds to the turning part 111 and presses on the turning part 111, causing the turning part 111 to tilt outwards from the end connected to the straight pipe part 112 to the end far away from the straight pipe part 112. The turning part 111 is inclined with respect to the straight pipe part 112. Specifically, the bottom end of the pre-turning forming inclined surface 2311 is further connected to a vertical forming surface 2312, and the angle between the vertical forming surface 2312 and the pre-turning forming inclined surface 2311 of the workpiece is 45°. During the stamping forming process, the vertical forming surface 2312 contacts the inner wall surface of the straight pipe part 112, keeping the straight pipe part 112 in a vertical state and causing the turning part 111 to start folding at the connection with the straight pipe part 112.

[0112] For further illustration, the second ejector rod 373 pushes out the workpiece, facilitating the grasping of the second transfer manipulator.

[0113] For further illustration, when the mold is closed, the bottom surface of the second stripper plate 233 contacts the surface of the second concave template 32 and does not interfere with the workpiece. When the mold is opened, the second stripper plate 233 is pushed open under the elastic force of the fifth elastic member 235 to push the workpiece away from the second punch 231, causing the workpiece to stay in the lower mold assembly 3, facilitating the operation of the second transfer manipulator.

[0114] For further illustration, the fourth elastic member 234 is a nitrogen spring, the fifth elastic member 235 is a spring, the sixth elastic member 371 is a urethane rubber, and the elastic force of the fourth elastic member 234 is much greater than the elastic force of the sixth elastic member 371, ensuring that the second upper pressing block 232 can press the second ejector rod 373 downward.

[0115] For further illustration, when performing the pre-turning step, a slower stamping speed can slow down the drawing speed of the outward turning and thinning of the workpiece. The multi-station die 1 is preferably operated at a stamping speed of 15 - 17 times per minute, and at this time, the forming effect of the workpiece is relatively ideal.

[0116] For further illustration, the third punch unit 24 includes a third punch 241, a third upper pressing block 242, a third stripper plate 243, a seventh elastic member 244 and an eighth elastic member 245. The third punch 241 is fixedly arranged at the bottom of the upper die base 21. The third upper pressing block 242 is movably arranged in the third punch 241 in the vertical direction through the seventh elastic member 244. The end of the third upper pressing block 242 away from the upper die base 21 protrudes from the third punch 241. The third stripper plate 243 is movably arranged on the upper die base 21 in the vertical direction through the eighth elastic member 245.

[0117] The third supporting and ejecting unit 38 includes a ninth elastic member 381, a third supporting block 382 and a third ejector rod 383. One end of the ninth elastic member 381 is fixedly connected to the lower supporting plate 35, the other end of the ninth elastic member 381 is connected to the bottom of the third supporting block 382, and the top of the third supporting block 382 is connected to the third ejector rod 383.

[0118] The lower die assembly 3 further includes a third lower backing plate 303. The third lower backing plate 303 is fixedly arranged between the third concave die plate 33 and the lower die base 30. The lower die base 30 and the third lower backing plate 303 are respectively provided with a third through hole 3031 in the vertical direction. The third concave die plate 33 is provided with a third material supporting channel 331 in the vertical direction. The third ejector rod 383 passes through the third through hole 3031 of the lower die base 30 and the third through hole 3031 of the third lower backing plate 303 and then inserts into the third material supporting channel 331. The third ejector rod 383 is provided with a third rod head 3831 for abutting against the upper surface of the third lower backing plate 303.

[0119] The third upper pressing block 242 and the third ejector rod 383 are arranged corresponding to each other. The third stripper plate 243 and the third concave die plate 33 are arranged corresponding to each other. The bottom of the third punch 241 is provided with a second forming step 2411, and the second forming step 2411 is in a right-angled shape.

[0120] Place the workpiece into the flattening station 103. When placing, orient the material turning part 111 of the workpiece towards the third punch unit 24. Close the mold to lower the upper mold base 21. The third upper pressing block 242 abuts against the third ejector rod 383 and presses the third ejector rod 383 downward. The ninth elastic member 381 undergoes elastic deformation until the third rod head 3831 of the third ejector rod 383 fits against the third lower backing plate 303, causing the third ejector rod 383 to stop in place (the third upper pressing block 242 presses the third ejector rod 383 in place. The workpiece falls freely or is pressed by the third punch 241 to reach the end face of the third ejector rod 383 before being force-formed. The third ejector rod 383 is a force-receiving member); the upper mold base 21 continues to descend. The third stripper plate 243 contacts the third concave template 33, and the eighth elastic member 245 begins to be compressed. In this continuously descending interval, the third punch 241 begins to contact the workpiece and presses it down to the top surface of the third ejector rod 383; the upper mold base 21 continues to descend, the eighth elastic member 245 continues to be compressed, and the third punch 241 punches the material turning part 111, making the angle between the material turning part 111 and the straight pipe part 112 90°. After completing the flattening step, open the mold. The upper mold base 21 ascends. The third stripper plate 243 pushes the workpiece downward away from the third punch 241 under the elastic action of the eighth elastic member 245, realizing the stripping of the workpiece from the third punch 241. After the third upper pressing block 242 disengages from the third ejector rod 383, the third ejector rod 383 moves upward under the elastic action of the ninth elastic member 381, pushing the workpiece upward to realize top push and ejection, and pushing the top end of the workpiece out of the third material supporting channel 331.

[0121] Further illustrate that the thickness of the third rod head 3831 is greater than the thickness of the first rod head 3631, and the thickness of the third rod head 3831 is the same as the thickness of the second rod head 3731. During the previous upsetting step, the entire straight pipe 11 is located inside the first material supporting channel 311. During the flattening step, the processing height of the workpiece is raised under the support of the third ejector rod 383, making the material turning part 111 located above the third material supporting channel 331, while the straight pipe part 112 is located inside the third material supporting channel 331. Since the second forming step 2411 is right-angled, when the third punch 241 punches the workpiece for forming, the second forming step 2411 corresponds to the material turning part 111 and punches the material turning part 111, making the angle between the material turning part 111 and the straight pipe part 112 90°.

[0122] Further illustrate that the third ejector rod 383 ejects the workpiece, facilitating the grasping of the third material transfer manipulator.

[0123] For further illustration, when the mold is closed, the bottom surface of the third stripper plate 243 contacts the surface of the third concave template 33 without interfering with the workpiece. When the mold is opened, the third stripper plate 243 is pushed open under the elastic force of the eighth elastic member 245 to push the workpiece away from the third punch 241, so that the workpiece stays in the lower mold assembly 3, facilitating the operation of the third transfer manipulator.

[0124] For further illustration, the seventh elastic member 244 is a nitrogen spring, the eighth elastic member 245 is a spring, and the ninth elastic member 381 is a polyurethane rubber. The elastic force of the seventh elastic member 244 is much greater than that of the ninth elastic member 381, ensuring that the third upper pressing block 242 can press the third ejector rod 383 downward.

[0125] For further illustration, the fourth punch unit 25 includes a fourth punch 251, a fourth stripper plate 252, and a tenth elastic member 253. The fourth punch 251 is fixedly arranged at the bottom of the upper mold base 21, and the fourth stripper plate 252 is movably arranged in the upper mold base 21 in the vertical direction through the tenth elastic member 253;

[0126] The blanking unit 39 includes a blanking plate 391, and the blanking plate 391 is inclined downward from one end close to the third supporting and ejecting unit 38 to the end far from the third supporting and ejecting unit 38;

[0127] The lower mold assembly 3 further includes a fourth lower backing plate 304. The fourth lower backing plate 304 is fixedly arranged between the fourth concave template 34 and the lower mold base 30. The fourth concave template 34, the fourth lower backing plate 304, and the lower mold base 30 are respectively provided with blanking channels 3041 for the workpiece after square blanking to fall. The blanking channels 3041 are arranged corresponding to the fourth punch 251. The fourth stripper plate 252 is arranged corresponding to the fourth concave template 34, and the blanking plate 391 is arranged below the blanking channels 3041.

[0128] Place the workpiece into the square blanking station 104. When placing, make the turning part 111 of the workpiece face the fourth punch unit 25. Close the mold to make the upper mold base 21 move downward. The fourth punch 251 punches the turning part 111 to cut the turning part 111 into a square shape. The workpiece after square blanking falls from the blanking channel 3041 to the blanking plate 391. Since the blanking plate 391 is inclined, the workpiece slides down obliquely from the blanking plate 391 to complete the discharging.

[0129] Specifically, the fourth punch 251 and the blanking channel 3041 are arranged on the same axis. When the mold is closed, the bottom surface of the fourth stripper plate 252 contacts the surface of the material turning part 111 that needs to be blanked. When the mold is opened, the fourth stripper plate 252 is bounced off under the elastic force of the tenth elastic member 253, and the waste material blanked from the material turning part 111 is separated from the fourth punch 251. The waste material remains on the upper surface of the fourth concave template 34, and the waste material can be blown away from the working area by blowing air.

[0130] Specifically, the tenth elastic member 253 is a spring.

[0131] Preferably, the upper die assembly 2 further includes a plurality of upper backing plates 26 and a plurality of fixing plates 27. The upper backing plates 26 are respectively arranged between the upper die base 21 and the first punch unit 22, between the upper die base 21 and the second punch unit 23, between the upper die base 21 and the third punch unit 24, and between the upper die base 21 and the fourth punch unit 25;

[0132] The fixing plates 27 are arranged corresponding to the upper backing plates 26 one by one. The fixing plates 27 are arranged on the lower end surfaces of the corresponding upper backing plates 26. The first punch unit 22, the second punch unit 23, the third punch unit 24, and the fourth punch unit 25 are respectively arranged on the corresponding fixing plates 27;

[0133] The lower die assembly 3 further includes a plurality of feet 305, and the feet 305 are fixedly connected between the lower die base 30 and the lower supporting plate 35.

[0134] Specifically, the first punch 221, the second punch 231, the third punch 241, and the fourth punch 251 are respectively fixedly arranged on the corresponding fixing plates 27. The fixing plates 27 can play a role in fixing the punches. By arranging the upper backing plates 26, the anti-impact force of the punches during stamping can be prevented from damaging the upper die base 21. By arranging the feet 305, the support stability of the lower die assembly 3 can be improved.

[0135] The working process of the above-mentioned multi-station mold 1 is as follows:

[0136] When the mold is in the open state (as shown in Figure 5 ), from left to right is the feeding direction of the workpiece. The loading manipulator clamps the pipe fittings with the cut length and places them into the upsetting station 101. The mold is closed and moves downward into Figure 6State, the first upper pressing block 222 abuts against the first ejector rod 363 and presses it down until the first ejector rod 363 abuts against the first lower backing plate 301 and the first ejector rod 363 stops in place. The upper die base 21 continues to move downward, the first stripper plate 223 contacts the first concave template 31, and the second elastic member 225 starts to be compressed. In this continuous downward movement interval, the first punch 221 starts to contact the straight pipe 11 and presses it down to the top surface of the first ejector rod 363. The upper die base 21 continues to move downward, the second elastic member 225 continues to be compressed, and the first punch 221 upsets the turning portion 111 of the straight pipe 11. After the upsetting step is completed, the mold is opened, the upper die base 21 moves upward, and the first stripper plate 223 pushes the workpiece downward away from the first punch 221 under the elastic action of the second elastic member 225, realizing the stripping of the workpiece from the first punch 221. After the first upper pressing block 222 disengages from the first ejector rod 363, the first ejector rod 363 moves upward under the elastic action of the third elastic member 361, pushing the workpiece upward to realize push ejection and discharging, and pushing the top end of the workpiece out of the first material supporting channel 311.

[0137] The loading manipulator grabs and feeds the straight pipe 11 of the blank, and the first transfer manipulator feeds the workpiece at the upsetting station 101 to the next pitch. The above-mentioned mold closing operation is repeated to perform the operations of the upsetting station 101 + the pre-turning station 102. After the forming of the two working steps is completed, the upward mold opening operation is repeated, and each workpiece is pushed out.

[0138] The loading manipulator grabs and feeds the straight pipe 11 of the blank, the first transfer manipulator feeds the workpiece at the upsetting station 101 to the next pitch, and the second transfer manipulator feeds the workpiece at the pre-turning station 102 to the next pitch. The above-mentioned mold closing operation is repeated to perform the operations of the upsetting station 101 + the pre-turning station 102 + the flattening station 103. After the forming of the three working steps is completed, the upward mold opening operation is repeated, and each workpiece is pushed out.

[0139] The loading robot grabs the straight tube 11 that is fed into the blank, the first material transfer robot transfers the workpiece in the upsetting station 101 to the next step, the second material transfer robot transfers the workpiece in the pre-turning station 102 to the next step, and the third material transfer robot transfers the workpiece in the flattening station 103 to the next step. The above-mentioned mold closing action is repeated to perform the operations of upsetting station 101 + pre-turning station 102 + flattening station 103 + square punching. After the four steps are completed, the upward mold opening action is repeated, and the workpieces in the upsetting station 101, pre-turning station 102 and flattening station 103 are pushed out. The workpiece in the square punching station 104 falls and slides out from the bottom of the mold. Synchronously, ventilation blows the waste material on the top surface of the fourth concave plate 34 away from the working area. The entire process of upsetting, pre-turning, flattening and square punching can be automated.

[0140] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A forming process for a square plug, characterized in that, It includes the following steps: Step A, upsetting: Taking a straight pipe as the base body, the straight pipe includes a material turning part and a straight pipe part connected to each other. The material turning part is arranged at one end of the straight pipe part. Upset the material turning part to reduce the height of the material turning part and increase the cross-section. Step B, pre-turning: Stamping the material turning part to turn the material turning part outwards from the end connected to the straight pipe part to the end far from the straight pipe part, and the material turning part is inclined relative to the straight pipe part, and the included angle between the material turning part and the straight pipe part is an acute angle. Step C, flattening: Stamping the material turning part to make the included angle between the material turning part and the straight pipe part be 90°. Step D, square blanking: Blanking the material turning part to cut the material turning part into a square shape. Step E, threading and flattening the end face: Cutting threads on the inner wall of the straight pipe part and cutting the end face of the material turning part far from the straight pipe part into a flat surface.

2. The forming process of the square plug according to claim 1, characterized in that, In step B, after stamping the material turning part, the included angle between the material turning part and the straight pipe part is 45°.

3. A forming system for a square plug, characterized in that, Applied to the forming process of the square plug as described in any one of claims 1 to 2, the forming system includes a multi-station die and a threading and flattening end face device. The multi-station die is sequentially provided with an upsetting station, a pre-turning station, a flattening station and a square blanking station along the forming sequence. The multi-station die is used to sequentially perform the steps of upsetting, pre-turning, flattening and square blanking on the straight pipe. The threading and flattening end face device is arranged downstream of the multi-station die. The threading and flattening end face device is used to cut threads on the inner wall of the straight pipe part and cut the end face of the material turning part far from the straight pipe part into a flat surface.

4. The forming system of the square plug according to claim 3, characterized in that, The forming system further includes: A loading manipulator, arranged upstream of the upsetting station, for loading the straight pipe to the upsetting station. A first transfer manipulator, arranged between the upsetting station and the pre-turning station, for moving the workpiece that has completed the upsetting step at the upsetting station to the pre-turning station. A second transfer manipulator, arranged between the pre-turning station and the flattening station, for moving the workpiece that has completed the pre-turning step at the pre-turning station to the flattening station. A third transfer manipulator, arranged between the flattening station and the square blanking station. The third transfer manipulator is used to move the workpiece that has completed the flattening step at the flattening station to the square blanking station.

5. The forming system of the square plug according to claim 3, characterized in that, The multi-station die includes an upper die assembly and a lower die assembly. The upper die assembly includes an upper die base and a first punch unit, a second punch unit, a third punch unit and a fourth punch unit sequentially arranged at the bottom of the upper die base along the forming sequence. The lower die assembly includes a lower die base and a first die plate, a second die plate, a third die plate and a fourth die plate sequentially and fixedly arranged on the lower die base. The lower die assembly further includes a lower supporting plate, and a first supporting and ejecting unit, a second supporting and ejecting unit, a third supporting and ejecting unit, and a blanking unit that are fixedly arranged on the lower supporting plate in the forming sequence; the lower supporting plate is arranged below the lower die base, the first supporting and ejecting unit, the second supporting and ejecting unit, and the third supporting and ejecting unit are used to support the workpiece to be formed and eject the formed workpiece, and the blanking unit is used to supply the workpiece that has completed square blanking to drop the material; The first punch unit, the first concave template are correspondingly arranged with the first supporting and ejecting unit and are located at the upsetting station, and the first punch unit is used to cooperate with the first concave template when the die is closed to perform the upsetting step on the straight pipe; The second punch unit, the second concave template are correspondingly arranged with the second supporting and ejecting unit and are located at the pre-flipping station, and the second punch unit is used to cooperate with the second concave template when the die is closed to perform the pre-flipping step on the workpiece; The third punch unit, the third concave template are correspondingly arranged with the third supporting and ejecting unit and are located at the flattening station, and the third punch unit is used to cooperate with the third concave template when the die is closed to perform the flattening step on the workpiece; The fourth punch unit, the fourth concave template are correspondingly arranged with the blanking unit and are located at the square blanking station, and the fourth punch unit is used to cooperate with the fourth concave template when the die is closed to perform the square blanking step on the workpiece.

6. The forming system of the square plug according to claim 5, characterized in that, The first punch unit includes a first punch, a first upper pressing block, a first stripper plate, a first elastic member, and a second elastic member. The first punch is fixedly arranged at the bottom of the upper die base. The first upper pressing block is movably arranged inside the first punch in the up and down direction through the first elastic member. The end of the first upper pressing block away from the upper die base protrudes from the first punch. The first stripper plate is movably arranged on the upper die base in the up and down direction through the second elastic member; The first supporting and ejecting unit includes a third elastic member, a first supporting block, and a first ejector rod. One end of the third elastic member is fixedly connected to the lower supporting plate, the other end of the third elastic member is connected to the bottom of the first supporting block, and the top of the first supporting block is connected to the first ejector rod; The lower die assembly further includes a first lower backing plate, which is fixedly arranged between the first concave template and the lower die base. The lower die base and the first lower backing plate are respectively provided with a first through hole in the up and down direction. The first concave template is provided with a first material supporting channel in the up and down direction. The first ejector rod passes through the first through hole of the lower die base and the first through hole of the first lower backing plate and then inserts into the first material supporting channel. The first ejector rod is provided with a first rod head for abutting against the upper surface of the first lower backing plate; The first upper pressing block and the first ejector rod are correspondingly arranged, the first stripper plate and the first concave template are correspondingly arranged. The top wall surface of the first material supporting channel is provided with an upsetting avoidance opening, and the bottom of the first punch is provided with a first forming step that cooperates with the upsetting avoidance opening.

7. The forming system of the square plug according to claim 5, characterized in that, The second punch unit includes a second punch, a second upper pressing block, a second stripper plate, a fourth elastic member, and a fifth elastic member. The second punch is fixedly arranged at the bottom of the upper die base. The second upper pressing block is movably arranged inside the second punch along the vertical direction through the fourth elastic member. The end of the second upper pressing block away from the upper die base protrudes from the second punch. The second stripper plate is movably arranged on the upper die base along the vertical direction through the fifth elastic member. The second supporting and ejecting unit includes a sixth elastic member, a second supporting block, and a second ejector rod. One end of the sixth elastic member is fixedly connected to the lower supporting plate, the other end of the sixth elastic member is connected to the bottom of the second supporting block, and the top of the second supporting block is connected to the second ejector rod. The lower die assembly further includes a second lower backing plate, which is fixedly arranged between the second concave die plate and the lower die base. The lower die base and the second lower backing plate are respectively provided with second through holes along the vertical direction. The second concave die plate is provided with a second material supporting channel along the vertical direction. The second ejector rod passes through the second through hole of the lower die base and the second through hole of the second lower backing plate and then inserts into the second material supporting channel. The second ejector rod is provided with a second rod head for abutting against the upper surface of the second lower backing plate. The second upper pressing block and the second ejector rod are arranged corresponding to each other. The second stripper plate and the second concave die plate are arranged corresponding to each other. The bottom of the second punch is provided with a pre-bending forming inclined surface.

8. The forming system of the square plug according to claim 5, characterized in that, The third punch unit includes a third punch, a third upper pressing block, a third stripper plate, a seventh elastic member, and an eighth elastic member. The third punch is fixedly arranged at the bottom of the upper die base. The third upper pressing block is movably arranged inside the third punch along the vertical direction through the seventh elastic member. The end of the third upper pressing block away from the upper die base protrudes from the third punch. The third stripper plate is movably arranged on the upper die base along the vertical direction through the eighth elastic member. The third supporting and ejecting unit includes a ninth elastic member, a third supporting block, and a third ejector rod. One end of the ninth elastic member is fixedly connected to the lower supporting plate, the other end of the ninth elastic member is connected to the bottom of the third supporting block, and the top of the third supporting block is connected to the third ejector rod. The lower die assembly further includes a third lower backing plate, which is fixedly arranged between the third concave die plate and the lower die base. The lower die base and the third lower backing plate are respectively provided with third through holes along the vertical direction. The third concave die plate is provided with a third material supporting channel along the vertical direction. The third ejector rod passes through the third through hole of the lower die base and the third through hole of the third lower backing plate and then inserts into the third material supporting channel. The third ejector rod is provided with a third rod head for abutting against the upper surface of the third lower backing plate. The third upper pressing block and the third ejector rod are arranged corresponding to each other. The third stripper plate and the third concave die plate are arranged corresponding to each other. The bottom of the third punch is provided with a second forming step, and the second forming step is in a right-angled shape.

9. The forming system of the square plug according to claim 5, characterized in that, The fourth punch unit includes a fourth punch, a fourth stripper plate, and a tenth elastic member. The fourth punch is fixedly arranged at the bottom of the upper die base. The fourth stripper plate is movably arranged in the upper die base in the up-and-down direction through the tenth elastic member. The blanking unit includes a blanking plate which is arranged to slope downwards from one end close to the third supporting and ejecting unit to the other end far from the third supporting and ejecting unit. The lower die assembly further includes a fourth lower backing plate which is fixedly arranged between the fourth concave die plate and the lower die base. The fourth concave die plate, the fourth lower backing plate, and the lower die base are respectively provided with blanking channels for the workpieces after square blanking to fall. The blanking channels are arranged corresponding to the fourth punch. The fourth stripper plate is arranged corresponding to the fourth concave die plate. The blanking plate is arranged below the blanking channels.

10. The forming system of the square plug according to claim 5, characterized in that, The upper die assembly further includes a plurality of upper backing plates and a plurality of fixing plates. The upper backing plates are respectively arranged between the upper die base and the first punch unit, between the upper die base and the second punch unit, between the upper die base and the third punch unit, and between the upper die base and the fourth punch unit. The fixing plates are arranged corresponding to the upper backing plates one by one. The fixing plates are arranged on the lower end surfaces of the corresponding upper backing plates. The first punch unit, the second punch unit, the third punch unit, and the fourth punch unit are respectively arranged on the corresponding fixing plates. The lower die assembly further includes a plurality of feet which are fixedly connected between the lower die base and the lower supporting plate.

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