Method for forming a flat workpiece blank with a concave notch

Abstract

The application discloses a kind of flat workpiece blank concave gap flanging processing forming methods.The method includes: preparing plate blank (1), and the plate blank is laid out with flat workpiece blank (11) on it;Punching process hole (13) is punched on the plate blank at the position where concave gap flanging needs to be processed and formed;Using hole expanding die device (2) to expand the process hole on the plate blank, and the process hole is expanded;Plate blank is processed by process hole punching, and flat workpiece blank is cut out, and the edge of the original process hole on the flat workpiece blank is flanging target concave edge;The flanging target concave edge on the flat workpiece blank is flanged, and then the edge of the flanging is trimmed, to process and form concave gap flanging.The concave gap flanging processing forming method of the application can make the formed concave gap flanging have little cracking phenomenon, avoid the situation that a large number of processed parts are scrapped, and reduce production cost.

Description

Technical Field

[0001] This invention relates to a flanging forming method, and more particularly to a method for flanging forming a concave notch on a flat workpiece blank. Background Technology

[0002] Flanging is a common process in stamping. It is relatively easy to achieve for softer blanks, but it is not easy to achieve for high-strength steel blanks, especially when performing flanging with insufficient material, which can easily lead to flanging cracks.

[0003] See Figure 1 , Figure 1 The image shown is of a sheet material with a concave notch flange. The concave notch flange refers to a flange formed at a concave notch on the edge of the sheet material, such as... Figure 1 The area indicated by arrow A is a typical example of a material-deficient flange. If the sheet material is high-strength steel, cracking is very likely to occur during the processing of the concave notch flange, resulting in a large number of scrapped parts and increased production costs.

[0004] Currently, the main method to solve the problem of material shortage cracking during flanging is to pre-press the billet into a certain shape before flanging, thus storing material and alleviating the degree of material shortage during the subsequent flanging process, thereby improving the problem of material shortage cracking during flanging. However, this method is not suitable for billets made of high-strength steel, because the billet will undergo work hardening during pre-pressing, and the plasticity of the billet will deteriorate, which will increase the risk of flanging cracking. Summary of the Invention

[0005] The purpose of this invention is to provide a method for forming a concave notch flange on a flat workpiece blank. This method can minimize cracking of the final formed concave notch flange, thereby avoiding a large number of scrapped parts and effectively reducing production costs.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] A method for forming a concave notch flange on a flat workpiece blank includes the following steps:

[0008] Step 1: Prepare the sheet metal blank, and lay out the flat workpiece blanks on the sheet metal blank;

[0009] Step 2: Punch process holes at the locations on the sheet metal blank where concave notches and flanges need to be formed;

[0010] Step 3: Use a hole-expanding die device to extrude and expand the process holes on the sheet metal blank to enlarge the process holes;

[0011] Step 4: Punch the process holes in the plate blank to cut out flat workpiece blanks. The edges of the original process holes on the flat workpiece blanks are the flanged concave edges.

[0012] Step 5: Flang the concave edge of the flat workpiece blank, and then trim the edge of the flange to form a concave notch flange.

[0013] Furthermore, step 1 also includes: two flat workpiece blanks are arranged on the plate blank, and the flanged concave edges of the two flat workpiece blanks are spliced ​​together opposite each other.

[0014] Furthermore, step 2 also includes: the process hole is a circular hole, an elliptical hole, or a square hole with rounded corners.

[0015] Furthermore, step 3 also includes: expanding the process hole by 0.2t to 2t, where t is the thickness of the plate blank.

[0016] Furthermore, the enlarging die device includes an upper die, a lower die, and a punch;

[0017] The upper and lower molds are both provided with vertical through holes in the middle. The hole shapes of the holes in the upper and lower molds are matched with the hole shapes of the process holes on the sheet metal blank. Furthermore, the holes in the upper and lower molds are larger than the process holes on the sheet metal blank.

[0018] The peripheral configuration of the punch matches the hole shape of the upper and lower dies. One end of the punch is the head end, and the other end is the tail end. The punch is composed of three segments connected together. From the tail end to the head end of the punch, the three segments are, in order, the tail segment, the expanding diameter segment, and the head segment. The tail segment is slightly thicker than the head segment, and the expanding diameter segment is a smooth transition segment between the tail segment and the head segment.

[0019] When using an enlarging punching device to extrude and expand the process holes on a sheet metal blank, the sheet metal blank is pressed between the upper and lower dies, with the process holes of the sheet metal blank aligned with the clearance holes of the upper and lower dies. Then, the head of the punch is pressed into the clearance holes of the upper and lower dies from the top of the upper die. During the pressing process, the head of the punch passes through the process hole of the sheet metal blank, and the enlarged diameter section of the punch extrudes the process hole as it passes through it, thus enlarging the process hole of the sheet metal blank.

[0020] Furthermore, the process holes on the sheet metal blank are circular holes, the clearance holes of the upper and lower dies are circular holes, the tail section and head section of the punch are both cylindrical sections, and the diameter expansion section of the punch is a conical section.

[0021] Furthermore, the angle between the generatrix of the conical surface of the expanded diameter section of the punch and the central axis of the punch ranges from 1 to 10 degrees.

[0022] Furthermore, the angle between the generatrix of the conical surface of the expanded diameter section of the punch and the central axis of the punch is 2.5 degrees.

[0023] Furthermore, the junction of the upper and lower mold openings with the pressure plate surface is rounded.

[0024] Furthermore, the material of the plate blank is high-strength steel.

[0025] In the concave notch flanging forming method of the present invention, before forming the concave notch flanging, the target concave edge of the flat workpiece blank is first extruded and expanded, that is, in step 3, the process hole on the plate blank is extruded and expanded using an enlarging die device. The target concave edge of the flanging is uniformly deformed during the extrusion and expansion process, which can repair the initial cracks generated during the punching process hole and suppress the expansion of cracks during the subsequent flanging process. Finally, the concave notch flanging can be formed by appropriately trimming the edge of the flanging.

[0026] Compared with the prior art, the concave notch flanging forming method of the present invention has the following advantages: In the concave notch flanging forming method of the present invention, before forming the concave notch flanging, the target concave edge of the flat workpiece blank is first squeezed and expanded, so that the final formed concave notch flanging has very few cracks, thereby avoiding a large number of scrapped parts and effectively reducing production costs. Attached Figure Description

[0027] Figure 1 A schematic diagram for processing and shaping a blank with a concave notch and flange;

[0028] Figure 2 This is a schematic diagram of the sheet metal blank prepared in the method for forming a concave notch flange on a flat workpiece blank according to the present invention.

[0029] Figure 3 This is a schematic diagram illustrating the use of an enlarging die device to extrude and expand the process holes of the sheet metal blank in the concave notch flanging forming method of the present invention.

[0030] Figure 4 This is a schematic diagram of the punch in the hole-expanding die device of the concave notch flanging forming method of the present invention;

[0031] Figure 5 This is a cross-sectional view of the process hole of the sheet metal blank being extruded and expanded by an enlarging die device in the concave notch flanging forming method of the present invention.

[0032] Figure 6 for Figure 5 Enlarged view of the area indicated by the middle arrow D;

[0033] Figure 7 This is a schematic diagram of the flat workpiece blank used in the concave notch flanging forming method of the present invention;

[0034] Figure 8 This is a flowchart of the concave notch flanging forming method of the present invention.

[0035] In the figure: 1-plate blank, 11-flat workpiece blank, 13-process hole, 2-expanding hole diameter punching die device, 21-upper die, 22-lower die, 23-punch, 231-tail section, 232-expanding diameter section, 233-head section. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0037] See Figures 2 to 8 This embodiment provides a method for forming a concave notch flange on a flat workpiece blank. The method is used to form a concave notch flange on a flat workpiece blank 11.

[0038] See Figure 8 The concave notch flanging forming method of this embodiment includes the following steps 1 to 5:

[0039] Step 1, see Figure 2 Prepare a plate blank 1. The material of the plate blank 1 is high-strength steel. Flat workpiece blank 11 is arranged on the plate blank 1.

[0040] In this embodiment, two flat workpiece blanks 11 are laid out on the sheet metal blank 1, with the two flat workpiece blanks 11 separated by the dotted line in the figure. In subsequent steps, the two flat workpiece blanks 11 will be cut apart using this dotted line as the punching line.

[0041] Step 2, see Figure 2 A process hole 13 is punched at the location where the concave notch flange needs to be formed on the sheet blank 1. The edge shape around the process hole 13 is consistent with the edge shape of the concave edge before the concave notch flange. The concave edge before the concave notch flange refers to the concave edge on the sheet blank 1 before the concave notch flange is formed.

[0042] In this embodiment, the process hole 13 is a circular hole. In other embodiments, the process hole can also be other shapes, such as an elliptical hole, a square hole with rounded corners, or other irregularly shaped holes, as long as the edges of the hole are smooth and without any included angles. The specific shape of the process hole depends on the shape of the concave notch of the concave notch flange.

[0043] Step 3, see Figure 3 and Figure 5 The process hole 13 on the sheet blank 1 is expanded by extruding the hole diameter punching die 2, thereby enlarging the process hole 13 by extrusion. The enlargement of the process hole 13 is 0.2t~2t, where t is the thickness of the sheet blank 1.

[0044] See Figure 3 , Figure 5 and Figure 6 The enlarging die device 2 includes an upper die 21, a lower die 22, and a punch 23.

[0045] Both the upper mold 21 and the lower mold 22 have vertically penetrating openings in the middle, and the opening diameters of the openings in the upper mold 21 and the lower mold 22 are the same. The opening shapes of the openings in the upper mold 21 and the lower mold 22 are matched with the opening shapes of the process holes 13 on the plate blank 1. Furthermore, the openings in the upper mold 21 and the lower mold 22 are slightly larger than the process holes 13 on the plate blank 1.

[0046] See Figure 3 , Figure 4 and Figure 5 The peripheral configuration of the punch 23 matches the hole shape of the upper die 21 and the lower die 22. One end of the punch 23 is the head end, and the other end is the tail end. The punch 23 is composed of three segments connected together, from the tail end to the head end, the three segments are, in sequence, the tail segment 231, the expanding diameter segment 232, and the head segment 233. Specifically, the segment containing the tail end of the punch 23 is the tail segment 231, the segment containing the head end of the punch 23 is the head segment 233, and the segment between the tail segment 231 and the head segment 233 is the expanding diameter segment 232. The peripheral configurations of the tail section 231, the expanding section 232, and the head section 233 of the punch 23 all match the hole shapes of the upper die 21 and the lower die 22. The tail section 231 is slightly thicker than the head section 233, while the expanding section 232 is a smooth transition section between the tail section 231 and the head section 233. Here, "smooth transition section" means that the peripheral surface at the junction of the expanding section 232 and the tail section 231 is smoothly transitioned, and the peripheral surface at the junction of the expanding section 232 and the head section 233 is also smoothly transitioned.

[0047] Specifically, in this embodiment, the process hole 13 on the sheet metal blank 1 is a circular hole. Therefore, the clearance holes of the upper die 21 and the lower die 22 are also circular holes, and the diameter of the clearance hole is slightly larger than the diameter of the process hole 13 on the sheet metal blank 1. The tail section 231 and the head section 233 of the punch 23 are both cylindrical sections, and the diameter of the tail section 231 is larger than the diameter of the head section 233. The expanding section 232 is a conical section. At the junction of the expanding section 232 and the tail section 231, the conical surface of the expanding section 232 smoothly transitions to the cylindrical surface of the tail section 231. At the junction of the expanding section 232 and the head section 233, the conical surface of the expanding section 232 smoothly transitions to the cylindrical surface of the head section 233. The diameter at the junction of the expanding section 232 and the tail section 231 is larger than the diameter at the junction of the expanding section 232 and the head section 233. The angle between the generatrix of the conical surface of the expanded diameter section 232 and the central axis of the punch 23 can be taken in the range of 1 to 10 degrees as needed. In this embodiment, the angle is taken as 2.5 degrees.

[0048] See Figure 5 When the process hole 13 on the sheet metal blank 1 is extruded and expanded using the enlarging die device 2, the sheet metal blank 1 with the process hole 13 is pressed between the upper die 21 and the lower die 22. The process hole 13 of the sheet metal blank 1 is aligned with the clearance holes of the upper die 21 and the lower die 22. Then, the head end of the punch 23 is pressed from the top of the upper die 21 into the clearance holes of the upper die 21 and the lower die 22. During the pressing process of the punch 23, the head section 233 of the punch 23 passes through the process hole 13 of the sheet metal blank 1, and the enlarging section 232 of the punch 23 will extrude the process hole 13 when passing through the process hole 13 of the sheet metal blank 1, thereby enlarging the process hole 13 of the sheet metal blank 1, and thus achieving the extrusion and expansion of the process hole 13 on the sheet metal blank 1.

[0049] See Figure 6 To prevent the process holes 13 in the sheet metal blank 1 from turning downwards during the extrusion and expansion process, it is usually necessary to round the corners at the junction of the empty holes and the pressure plate surfaces of the upper die 21 and the lower die 22. The pressure plate surfaces referred to here are the end faces of the upper die 21 and the lower die 22 that press the sheet metal blank 1. For the upper die 21, the pressure plate surface is its lower end face; for the lower die 22, the pressure plate surface is its upper end face.

[0050] It should be noted that the enlarging die device 2 is installed in the pressure equipment, and the pressing action of the upper die 21 and the punch 23 is driven by the pressure equipment.

[0051] See Figure 6 It should be noted that, since the clearance holes of the upper mold 21 and the lower mold 22 are slightly larger than the process holes 13 on the sheet metal blank 1, the edges of the process holes 13 on the sheet metal blank 1 protrude beyond the inner walls of the clearance holes of the upper mold 21 and the lower mold 22, such as... Figure 6 As indicated by the middle arrow B, this provides an expanded operating space for the compression and expansion.

[0052] Step 4: Punch the process holes in the sheet blank 1.

[0053] See Figure 2 and Figure 7 The aforementioned process hole punching refers to the punching of process holes 13 on the sheet metal blank 1 by a punching line passing through the punching of process holes 13. The punching line is as follows: Figure 2 The dotted line in the diagram. After being punched through the process holes, the sheet metal blank 1 is divided into two flat workpiece blanks 11. The edges of the original process holes 13 on the flat workpiece blanks 11 serve as the target concave edge for flanging. The target concave edge for flanging is as follows: Figure 7 The location indicated by the middle arrow C.

[0054] Step 5: Flanging the concave edges of the two flat workpiece blanks 11. At this time, the flanging is a material shortage flanging. The edges of the material shortage flanging often have some small cracks. Therefore, it is necessary to trim the edges of the flanging and cut off the flanging edges to finally process and form the concave notch flanging.

[0055] In the concave notch flanging forming method of this embodiment, before forming the concave notch flanging on the flat workpiece blank 11, the target concave edge of the flanging is first extruded and expanded. That is, in step 3, the hole-expanding punching die device 2 is used to extrude and expand the process hole 13 on the plate blank 1 (the target concave edge of the flanging is a part of the process hole 13). The target concave edge of the flanging deforms uniformly during the extrusion and expansion process, which can repair the initial cracks generated during the punching process hole and suppress the expansion of cracks during the subsequent flanging process. Finally, only the edge of the flanging needs to be properly trimmed to form the concave notch flanging. The final formed concave notch flanging rarely cracks, thereby avoiding a large number of scrapped parts and effectively reducing production costs.

[0056] It should be noted that in this embodiment, the concave notch of the final processed concave notch flange is a semi-circular concave notch. Therefore, in order to save sheet material, two flat workpiece blanks can be laid out on a sheet material blank, and the flange target concave edges of the two laid-out flat workpiece blanks are spliced ​​together opposite each other. In this way, as long as a process hole is punched at the splicing point of the flange target concave edges of the two laid-out flat workpiece blanks on the sheet material blank, the flange target concave edges of the two flat workpiece blanks can be punched out. After punching through the process hole, two complete flat workpiece blanks can be obtained.

[0057] It should be noted that in this embodiment, the process hole 13 punched on the sheet metal blank 1 is a circular hole. Therefore, the clearance holes of the upper die 21 and lower die 22 of the hole-expanding die device 2 should be circular holes that match the process hole 13. Furthermore, the periphery of the process hole 13 on the sheet metal blank 1 should be consistent with the periphery of the concave edge before the concave notch flange. In other words, the hole shape of the clearance holes of the upper die 21 and lower die 22 of the hole-expanding die device 2 ultimately depends on the periphery of the concave edge before the concave notch flange. Similarly, in other embodiments, if the process hole on the sheet metal blank is an elliptical hole or a square rounded-corner hole, the clearance holes of the upper die and lower die of the hole-expanding die device should be elliptical holes or square rounded-corner holes that match the process hole.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of forming a flat plate workpiece blank into a flanged recess, the method comprising: It comprises the following steps: ​ Step 1, preparing a plate blank (1) on which a flat plate workpiece blank (11) is laid out; Step 2, punching a process hole (13) on the plate blank (1) at a position where a concave notch flange needs to be formed; Step 3, using a hole expanding die device (2) to expand the process hole (13) on the plate blank (1) by extrusion, and expand the process hole (13); Step 4, punching the plate blank (1) by process hole, and cutting out the flat plate workpiece blank (11), and the edge of the original process hole (13) on the flat plate workpiece blank (11) is the flange target concave edge; Step 5, flanging the flange target concave edge on the flat plate workpiece blank (11), and then trimming the edge of the flange, so as to form a concave notch flange; The step 1 further comprises: two flat plate workpiece blanks (11) are laid out on the plate blank (1), and the flange target concave edges of the two flat plate workpiece blanks (11) are oppositely spliced together. The hole expanding die device (2) comprises an upper die (21), a lower die (22) and a punch (23); The middle part of the upper die (21) and the lower die (22) is provided with a vertical through hole, the hole type of the hole of the upper die (21) and the lower die (22) matches the hole type of the process hole (13) on the plate blank (1), and the hole of the upper die (21) and the lower die (22) is larger than the process hole (13) on the plate blank (1); The peripheral configuration of the punch (23) matches the hole type of the hole of the upper die (21) and the lower die (22), one end of the punch (23) is a head end, the other end is a tail end, the punch (23) is composed of three segment bodies, from the tail end to the head end of the punch (23), the three segment bodies are tail segment (231), diameter expanding segment (232) and head segment (233) in turn, the tail segment (231) is slightly thicker than the head segment (233), and the diameter expanding segment (232) is a smooth transition segment between the tail segment (231) and the head segment (233); When the hole expanding die device (2) is used to extrude and expand the process hole (13) on the plate blank (1), the plate blank (1) is pressed between the upper die (21) and the lower die (22), the process hole (13) of the plate blank (1) is aligned with the hole of the upper die (21) and the lower die (22), and then the head end of the punch (23) is pressed into the hole of the upper die (21) and the lower die (22) from the upper part of the upper die (21), in the process of pressing the punch (23), the head segment (233) of the punch (23) passes through the process hole (13) of the plate blank (1), and the diameter expanding segment (232) of the punch (23) extrudes the process hole (13) when passing through the process hole (13) of the plate blank (1), so that the process hole (13) of the plate blank (1) is expanded.

2. The method of claim 1, wherein: The step 2 further comprises: the process hole (13) is a circular hole, an oval hole or a square round corner hole.

3. The method of claim 1, wherein: The step 3 further comprises: the expansion range of the process hole (13) is 0.2t~2t, wherein t is the thickness of the plate blank (1).

4. The method of claim 1, wherein: The process hole (13) on the plate blank (1) is a circular hole, the clearance hole of the upper die (21) and the lower die (22) is a circular hole, the tail section (231) and the head section (233) of the punch (23) are both cylindrical section bodies, and the diameter expansion section (232) of the punch (23) is a conical section body.

5. The method of claim 4, wherein: The included angle between the generatrix of the conical surface of the diameter expansion section (232) of the punch (23) and the central axis of the punch (23) is in the range of 1-10 degrees.

6. The method of claim 5, wherein: The included angle between the generatrix of the conical surface of the diameter expansion section (232) of the punch (23) and the central axis of the punch (23) is 2.5 degrees.

7. The method of claim 1, wherein: The intersection part between the clearance hole of the upper die (21) and the lower die (22) and the pressing plate surface is rounded.

8. The method of claim 1, wherein: The material of the plate blank (1) is high-strength steel.

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