Automatic cold forming process for metal clips

Abstract

The invention discloses an automated cold forming process for metal clips, and relates to the technical field of clip production processes. The automated cold forming process for metal clips can disperse the stress of materials during deformation through multiple step-by-step stamping and bending, reduce stress concentration and avoid cracks caused by excessive strain. Multiple stamping allows for more precise control of the strain rate of each stamping, which helps to improve the plasticity of the material and reduce damage accumulation. Compared with existing production processes, the process can not only effectively solve the problem of product molding cracking in the prior art and improve product molding quality, but also has fewer process steps, requires less manpower and has high production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of clip production technology, in particular to an automatic cold forming process for metal clips. Background Art

[0002] There is a metal clip shaped like Fig.15 As shown, it consists of two long finished handle parts, using SUS430 material with a Vickers hardness greater than or equal to 220HV-240HV. Based on the need to strengthen the bending stress points of the thin plate, the product needs to use a forming process to punch out a shallow "C" arc surface in the cross-sectional direction of the product's length direction, so a stamping die is required.

[0003] The existing Chinese invention patent with publication number CN117324486A discloses a continuous stamping die for hardware and a stamping method thereof, including an upper die assembly and a lower die assembly for performing progressive stamping processing on hardware. The upper die assembly and the lower die assembly are sequentially provided with a first punching mechanism, a second punching mechanism, a trimming mechanism, a stamping mechanism, an edge bending mechanism, an edge cutting mechanism and a material lowering mechanism along the material belt transmission direction. By adopting a continuous stamping method, multiple processes of hardware can be completed in one stamping process, thereby significantly improving production efficiency.

[0004] There is also a Chinese utility model patent with authorization announcement number CN214639591U, which discloses a continuous mold for stainless steel clips. Each station of the mold completes the processes of punching guide holes - punching special-shaped holes - forming - cutting, and small pieces are collected. These actions are completed in the process of opening and closing the mold once. The improvement of this design is that complex molding can be done on a set of molds. Compared with the previous and subsequent processes plus a single punching die, there is a great improvement and improved production efficiency.

[0005] Another example is the Chinese invention patent with publication number CN117840706A, which discloses a stamping and bending one-piece forming process for sheet metal parts. By heating and softening qualified sheets, it is possible to avoid cracking of the sheets due to excessive stamping pressure during the stamping process. The cylinder on the stamping and bending forming equipment is used to push the punch down to contact the sheet, and to push the top plate down to complete the stamping and bending one-piece forming of the sheet.

[0006] The above-mentioned stamping die and stamping bending process have the following problems when producing our long finished handle parts: For the first one: a hardware continuous stamping die and its stamping method and the second one: a stainless steel clip continuous die, only one stamping process was used for product stamping testing. During the test product molding process, it was found that: We conducted mechanical property analysis on two SUS430 materials (the hardness of the first material is the Vickers hardness value range of 220HV-240HV and the second material is the Vickers hardness value range of 160HV-180HV). When the hardness of the stainless steel material becomes higher, the plasticity and toughness of the material will be significantly reduced. When using the Vickers hardness value in the range of 220HV-240HV After the stainless steel SUS430 material is formed into a shallow "C" arc surface in the cross-sectional direction of the product length direction, the "C" outer arc surface of the product shows obvious crack lines in the drawing direction (i.e., the rolling direction of the material), and the transverse cross-sectional characteristics of the crack lines are "V"-shaped cracks that penetrate into the middle layer of the material. If there is tearing, it does not meet the general surface specification standards of the product; for the third: a stamping and bending one-piece forming process for sheet metal parts, which adopts a heat softening process to avoid cracking during stamping, can solve the problem of crack lines, but the number of processes increases, more workers are required to participate, and the production efficiency is low. Under the current mainstream manufacturing industry's promotion of automation and less manual work, the shortcomings of backward technology are highlighted. Summary of the invention

[0007] In order to overcome the deficiencies of the prior art, the present invention provides an automated cold forming process for a metal clip, so as to achieve the purpose of avoiding cracks on the product during stamping without increasing the production process and ensuring production efficiency.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an automated cold forming process for a metal clip, which requires the use of a stamping and bending device, the stamping and bending device comprising a second lower die set and a second upper die set, the second lower die set comprising a plurality of second lower dies that are linearly and equidistantly distributed, each of the second lower dies having a top surface provided with a long strip of raised portion along its length direction, the top surface of the raised portion being arc-shapedly bent downward from the middle position to the edges on all sides, the distance from the highest point of the raised portion on each of the second lower dies that are linearly and equidistantly distributed to the top surface of the second lower dies gradually increases, at least two of the second lower dies having arc-shaped bending grooves on their top surfaces along their width direction, the bending grooves being perpendicular to and not in contact with the raised portion, the second upper die set comprising a plurality of second upper dies that are linearly and equidistantly distributed, each of the second upper dies being correspondingly located directly above the second lower dies, each of the second upper dies being provided with a recessed portion that matches the raised portion, and a protruding portion being provided on the bottom surface of the second upper die corresponding to the second lower dies having the bending groove;

[0009] The clip comprises two semi-finished handle parts, each of which comprises a connecting unit and a clamping unit, the two clamping units facing each other are concave from all sides to the center, the two connecting units facing each other are gradually bent away from the middle to both ends, and the end of the connecting unit away from the clamping unit is straight-edged, and the cold forming process comprises the following steps:

[0010] One: a flat metal long thin plate is divided into a connecting part and a clamping part, and the flat metal long thin plate is placed on the second lower die where the distance from the highest point of the raised part to the top surface of the second lower die is the smallest for the first stamping and bending, wherein the clamping part is directly opposite to the raised part on the second lower die, so that the clamping part of the flat metal long thin plate is concave;

[0011] Second, the metal long strip thin plates are sequentially transferred to the remaining second lower dies which are linearly and equidistantly distributed for gradual stamping and bending, so that the depression degree of the clamping portion of the metal long strip thin plates gradually deepens, until the depression degree of the clamping portion of the metal long strip thin plates matches the depression degree of the clamping unit of the semi-finished handle portion, and at this time, the connecting portion of the metal long strip thin plates is bent at one end connected to the clamping portion through the bending groove and the protruding portion, until the bending degree of one end of the connecting portion of the metal long strip thin plates matches the bending degree of the connecting unit of the semi-finished handle portion, thereby obtaining a semi-finished handle portion;

[0012] Three: bend the straight sides of the connection units of the two semi-finished handle parts, fit them together and rivet them together. At this time, there is a gap between the clamping units of the two semi-finished handle parts, and a complete clip is obtained.

[0013] Preferably, the second lower molds and the second upper molds are each provided with 5-9 pieces, and after the second lower molds and the second upper molds thereon are punched, the depression degree of the clamping part of the metal long strip thin plate is deepened by 0.4mm-0.7mm each time.

[0014] Preferably, a punching device and a three-in-one feeding device are also used, the three-in-one feeding device includes a stainless steel coil rack, a flattening machine and a feeder, the punching device includes a first upper die set and a first lower die set, the top surface of the first lower die set is provided with at least one group of punching groups along its length direction, each group of the punching groups includes a plurality of punching holes, the first upper die set is located directly above the first lower die set, the first upper die set is provided with a punching piece adapted and corresponding to the punching holes, the punching holes include cutting holes and rivet holes, and the production process of the flat metal long strip sheet includes: under the traction of the feeder, the metal strip wound on the stainless steel coil rack is pulled through the flattening machine for flattening, and then equidistantly transported to the first upper die set, and cut through the punching device, thereby obtaining a flat metal long strip sheet;

[0015] The cold forming process also includes: through the cutting holes and rivet holes on the first lower die group cooperating with the adaptive and corresponding punching parts on the first upper die group, the connecting part of the metal long strip sheet away from the clamping part is cut into an arc-shaped cutting surface, and a rivet hole is punched out on the connecting part of the flat metal long strip sheet, which is used for subsequent riveting to fit and rivet the connecting units of the two semi-finished handle parts.

[0016] Preferably, the punching holes also include a circular hanging hole and at least one stamping and bending positioning hole. The second lower mold is provided with a stamping positioning column adapted to the stamping and bending positioning hole. The circular hanging hole and the stamping and bending positioning hole on the first lower mold group cooperate with the corresponding punching parts on the first upper mold group to punch out circular holes on the connecting part of the flat metal long strip sheet, and punch out stamping positioning holes on the clamping part of the flat metal long strip sheet.

[0017] Preferably, a first transfer device and a second transfer device are also required. The first transfer device is used to automatically transfer the long metal strips obtained by punching to the second lower mold, and the second transfer device is used to transfer the long metal strips to each second lower mold one by one. The punching device and the stamping and bending device are arranged in parallel, and the first upper mold group and the second upper mold are fixed on the same fixed plate, which is driven up and down by a driving member. The punching device, the first transfer device and the stamping and bending device are arranged in a U shape.

[0018] Preferably, an injection molding device is also required to injection-mold and wrap the first injection molding part and the second injection molding part on the outer surfaces of the clamping unit and the connecting unit facing one end and the other end of the semi-finished handle part, respectively, so as to obtain a finished handle part. The second injection molding part is made of nylon material, and the first injection molding part is made of silicone material. The injection molding equipment includes a third lower mold and a third upper mold. The third lower mold is provided with an injection molding positioning column adapted to the circular punching hole, which is used to position the semi-finished handle part on the third lower mold.

[0019] Preferably, the punching holes also include a plurality of injection molding anti-slip fixing holes, and through the cooperation of the injection molding anti-slip fixing holes on the first lower mold group and the corresponding punching parts on the first upper mold group, a plurality of injection molding positioning punching holes are punched out on the clamping part of the flat metal long strip thin plate. After the clamping unit of the semi-finished handle part is injection molded to wrap the first injection molding part and the second injection molding part, the injection molding positioning punching holes and the stamping positioning punching holes are filled with nylon or silicone.

[0020] Preferably, the wall thickness between two adjacent punching holes is not less than 8 mm. When the distance between any two punching locations of the circular punching hole, the arc-shaped cutting surface, the stamping positioning punching hole and the injection molding positioning punching hole is less than 8 mm, the two punching locations are punched out twice.

[0021] Preferably, the last four second lower molds are provided with bending grooves, two in each group, and the depths of the two groups of bending grooves are 0.8mm-1mm and 3.5mm-3.7mm respectively. After the two groups of bending grooves are stamped and bent, the angles between the plane where the connecting part of the metal long strip is away from one end of the clamping part and the cross-section of the deepest point of the bending groove are 3°-4° and 8°-9°.

[0022] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0023] (1) The present invention can disperse the stress of the material during the deformation process by multiple step-by-step stamping and bending, reduce stress concentration and avoid cracks caused by excessive strain. Multiple stamping allows more precise control of the strain rate of each stamping, which helps to improve the plasticity of the material and reduce damage accumulation. Compared with the existing production process, it can not only effectively solve the problem of product molding cracking in the prior art and improve the product molding quality, but also has fewer process steps, less labor and high production efficiency.

[0024] (2) By setting the punching device, the first transfer device and the stamping and bending device in a U shape, the first transfer device can be used to transfer the punching and bending device to achieve continuous and uninterrupted work. Compared with the existing linear continuous stamping die, it not only avoids the trouble of bending after the punching and then transferring the material, but also improves the efficiency. Although the present invention adds the first transfer device, the punching device, the first transfer device and the stamping and bending device are set in a U shape, and the structural position layout is more reasonable. The space occupied by the equipment is reasonably arranged to avoid the equipment being too long to be well placed in the factory building, and to achieve continuous and uninterrupted punching, cutting and stamping and bending of long metal sheets;

[0025] (3) The present invention forms a complete processing technology for metal clips by combining a three-in-one feeding device, a punching device, a stamping and bending device, and an injection molding device. The process is highly automated and closely linked. When the punching device cuts the flattened metal strip to obtain a long metal sheet, circular punching holes required for subsequent hanging and riveting holes required for riveting are punched out in advance on the long metal sheet, and punching positioning punching holes placed on the second lower mold are convenient for rapid and accurate positioning of the subsequent punching and bending, as well as injection molding positioning punching holes on the clamping unit of the semi-finished handle part to ensure that the first injection molding part and the second injection molding part are stably located. The reasonable arrangement of the punching holes on the first lower mold assembly ensures that the distance between the inner walls of the punching holes will not be less than 8 mm. The punching work is performed in multiple times to avoid the problem of the tension that cannot be eliminated due to the excessively small wall thickness of two adjacent punching holes during one punching and cutting process, thereby avoiding the first lower mold assembly from being broken during punching and cutting.

[0026] (4) By filling the set injection molding positioning punch hole and the stamping positioning punch hole with nylon or silicone, the first injection molding part and the second injection molding part will wrap and hide the stamping positioning punch hole and the injection molding positioning punch hole, so that the outer surface of the final finished handle portion will not have any extra punching defects. At the same time, when the stamping positioning punch hole and the injection molding positioning punch hole are filled with nylon or silicone, it can ensure that the first injection molding part and the second injection molding part are more stably located on the clamping unit of the semi-finished handle portion, thereby preventing them from falling off from the outer surface of the finished handle portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the driving mechanism and the blanking device of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the driving mechanism and the stamping and bending equipment of the present invention;

[0030] Figure 4 This is a schematic diagram of the second lower mold structure of the present invention;

[0031] Figure 5 This is a schematic diagram of the second upper mold structure of the present invention;

[0032] Figure 6 This is a schematic diagram of the first lower die set and the punching hole structure in the first embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the structure of the first upper module in the first embodiment of the present invention;

[0034] Figure 8 It is a schematic diagram of the structure of the punching piece and the limit block of the present invention;

[0035] Fig. 9 It is a schematic diagram of the structure of the material strip before processing and the metal long thin plate obtained after punching in the present invention;

[0036] Fig.10 A schematic diagram of a pair of strip punching and cutting variation structures according to an embodiment of the present invention;

[0037] Fig.11 This is a schematic diagram of the structure of punching and cutting of the material strip according to the second embodiment of the present invention;

[0038] Fig.12 This is a schematic diagram of the seven-time molding structure change of the handle portion of the present invention;

[0039] Fig.13 This is a schematic diagram of the structure of the semi-finished handle portion of the present invention;

[0040] Fig.14 This is a schematic diagram of the structure of the handle portion of the finished product of the present invention;

[0041] Fig.15 It is a schematic diagram of the existing metal clip structure;

[0042] Among them: 1. first lower die set; 101. first lower die unit; 102. second lower die unit; 2. punching hole; 21. first positioning hole; 22. second positioning hole; 23. punching and bending positioning hole; 24. fourth positioning hole; 25. fifth positioning hole; 26. round hanging hole; 27. rivet hole; 28. cutting hole; 3. first upper die set; 4. punching piece; 41. first punching rod; 42. second punching rod; 43. punching block; 44. fourth punching rod; 5. Second lower mold; 51, raised portion; 52, bending groove; 53, limiting column; 6, limiting mechanism; 61, limiting groove; 62, elastic limiting rod; 63, limiting block; 64, limiting hole; 7, driving mechanism; 71, driving member; 72, fixing plate; 8, supporting plate; 9, second upper mold; 91, recessed portion; 92, protruding portion; 93, limiting opening; 10, first transfer device; 11, supporting rod; 12, material taking assembly; 13, feed guide plate; 14, discharge plate. DETAILED DESCRIPTION

[0043] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained in conjunction with specific embodiments below. However, the following embodiments are only preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without making any creative work all belong to the protection scope of the present invention.

[0044] like Figure 1-Figure 5 As shown, the present invention provides an automated cold forming process for a metal clip, which requires the use of a stamping and bending device, which includes a second lower die set and a second upper die set, wherein the second lower die set includes a plurality of second lower dies 5 that are linearly and equidistantly distributed, wherein the top surface of each second lower die 5 is provided with a long strip-shaped raised portion 51 along its length direction, wherein the top surface of the raised portion 51 is bent in an arc shape downward from the middle position to the edges around it, and the distance from the highest point of the raised portion 51 on each linearly and equidistantly distributed second lower die 5 to the top surface of the second lower die 5 is gradually increased. Gradually increasing, at least two second lower molds 5 have arc-shaped bending grooves 52 on their top surfaces along their width direction, the bending grooves 52 are perpendicular to and do not contact the protrusions 51, the second upper mold group includes a plurality of second upper molds 9 that are linearly and equidistantly distributed, each second upper mold 9 is correspondingly located directly above the second lower mold 5, and each second upper mold 9 directly above the second lower mold 5 is provided with a recessed portion 91 adapted to the protrusion 51, and the bottom surface of the second upper mold 9 corresponding to the second lower mold 5 having the bending grooves 52 is provided with a protrusion 92;

[0045] like Figure 13-Figure 15As shown, the clip includes two semi-finished handle parts, each semi-finished handle part includes a connecting unit and a clamping unit, the two clamping units are concave from the surrounding to the center on one side, and the two connecting units are gradually bent away from the middle to the two ends on the opposite side, and the end of the connecting unit away from the clamping unit is a straight edge bend (to facilitate the subsequent two semi-finished handle parts to be fitted and riveted into a clip), and the end of the connecting unit and the clamping unit facing each other is set as an arc edge bend. The cold forming process includes the following steps:

[0046] One: a flat metal long thin plate is divided into a connecting part and a clamping part, and the flat metal long thin plate is placed on the second lower mold 5 where the distance from the highest point of the protrusion 51 to the top surface of the second lower mold 5 is the smallest, and the first stamping and bending is performed, wherein the clamping part is directly opposite to the protrusion 51 on the second lower mold 5, so that the clamping part of the flat metal long thin plate is concave;

[0047] Second, the metal long strip thin plate is transferred to the remaining second lower molds 5 which are linearly and equidistantly distributed for gradual stamping and bending, so that the depression degree of the clamping portion of the metal long strip thin plate gradually deepens, until the depression degree of the clamping portion of the metal long strip thin plate matches the depression degree of the clamping unit of the semi-finished handle portion, and at this time, the connecting portion of the metal long strip thin plate is bent at one end connected to the clamping portion through the bending groove 52 and the protrusion 92, until the bending degree of one end of the connecting portion of the metal long strip thin plate matches the bending degree of the connecting unit of the semi-finished handle portion, thereby obtaining a semi-finished handle portion (such as Fig.13 shown);

[0048] 3. Bending and riveting the straight sides of the connection units of the two semi-finished handle parts, a gap is formed between the clamping units of the two semi-finished handle parts, and a complete clip is obtained;

[0049] Long metal sheets are prone to cracking when bent along their length at one time. The present invention can disperse the stress of the material during deformation by performing multiple step-by-step stamping and bending, reduce stress concentration and avoid cracks caused by excessive strain. Multiple stamping allows for more precise control of the strain rate of each stamping, which helps to improve the plasticity of the material and reduce damage accumulation. Compared with existing production processes, the present invention can not only effectively solve the problem of product molding cracking in the prior art and improve product molding quality, but also has fewer process steps, requires less manpower and has high production efficiency.

[0050] like Figure 3 As shown, the second lower mold 5 and the second upper mold 9 are both provided with 5-9 pieces. After each second lower mold 5 and the second upper mold 9 thereon are punched, the concave degree of the clamping part of the metal long thin plate is deepened by 0.4mm-0.7mm each time;

[0051] The total bending depth is about 3.5 mm. When the number of the second lower molds 5 is less than 5, the bending depth will increase by more than 0.7 mm each time, which will easily cause cracks. When the number of the second lower molds 5 is greater than 9, the mold cost will increase.

[0052] It is also necessary to use a punching device and a three-in-one feeding device, which includes a stainless steel coil rack, a flattening machine and a feeder (this is a common device in stamping equipment, not shown in the figure, and the specific principle is not described in detail). The first lower die set 1 is provided with a feed guide plate 13 and a discharge plate 14 on opposite sides, and the feed guide plate 13 is located between the three-in-one feeder and the first lower die set 1;

[0053] like Figure 2 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, the punching equipment includes a first upper die set 3 and a first lower die set 1. The top surface of the first lower die set 1 is provided with at least one group of punching groups along its length direction. Each group of punching groups includes a plurality of punching holes 2. The first upper die set 3 is located directly above the first lower die set 1. The first upper die set 3 is provided with a punching piece 4 adapted and corresponding to the punching holes 2. The punching holes 2 include cutting holes 28 and rivet holes 27. The production process of the flat metal long strip sheet includes: under the traction of the feeder, the metal strip wound on the stainless steel coil rack is pulled through the flattening machine for flattening, and then equidistantly transported to the first upper die set 3, and cut through the punching equipment to obtain a flat metal long strip sheet;

[0054] The cold forming process also includes: cutting the connecting portion of the metal long sheet away from the clamping portion into an arc-shaped cutting surface through the cutting hole 28 and the rivet hole 27 on the first lower die set 1 and cooperating with the corresponding punching piece 4 on the first upper die set 3, and punching out a rivet hole on the connecting portion of the flat metal long sheet, so as to rivet the connecting units of the two semi-finished handles together with the subsequent rivets;

[0055] Two sets of punching groups are arranged here in parallel and symmetrically on the first lower die set 1, so that two flat long metal strips can be produced by punching at one time. By setting up a three-in-one feeding device, the leveling and equidistant traction and transportation of the wound metal strip can be realized. After it is transported to the punching equipment, the punching part 4 includes a punching block 43 for cutting the metal long strip and a first punching rod 41 for punching the riveting holes. After the metal strip is leveled and transported to the punching equipment, automatic punching is performed to obtain a flat long metal strip.

[0056] like Figure 6 , Figure 7 , Figure 8 and Fig. 9As shown, the punching hole 2 also includes a circular hanging hole 26 and at least one punching and bending positioning hole 23. The second lower die 5 is provided with a punching positioning column adapted to the punching and bending positioning hole 23. The circular hanging hole 26 and the punching and bending positioning hole 23 on the first lower die set 1 cooperate with the corresponding punching piece 4 on the first upper die set 3 to punch out a circular punching hole on the connecting portion of the flat metal long strip sheet, and punch out a punching positioning punching hole on the clamping portion of the flat metal long strip sheet;

[0057] The punching member 4 includes a second punching rod 42 for punching out a circular punching hole and a fourth punching rod 44 for punching out a punching positioning punching hole. The punched circular punching hole facilitates the subsequent hanging of the clip on a nail or hook on the wall. The punching positioning punching hole facilitates the subsequent accurate positioning and rapid placement of the metal long sheet on the second lower mold 5.

[0058] Furthermore, a limiting unit is provided on a surface facing the second lower mold 5 and the second upper mold 9, and the limiting unit includes a plurality of limiting columns 53 fixed to the bottom surface of the second lower mold 5 and a limiting opening 93 opened on the top surface of the second upper mold 9 and facing the limiting columns 53;

[0059] By setting the limit column 53, the metal long thin plate can be positioned and placed more accurately, so as to facilitate the subsequent accurate stamping work. By setting the limit opening 93, when the driving mechanism 7 drives the second upper mold 9 to move downward, the limit column 53 can enter the limit opening 93 to ensure the normal mold closing and stamping of the second lower mold 5 and the second upper mold 9.

[0060] like Figure 1-Figure 3 As shown, a first transfer device 10 and a second transfer device are also required. The first transfer device 10 is used to automatically transfer the metal long thin plate obtained by punching to the second lower mold 5, and the second transfer device is used to transfer the metal long thin plate to each second lower mold 5 one by one. The punching device and the stamping and bending device are arranged in parallel. The first upper mold group 3 and the second upper mold 9 are fixed on the same fixed plate 72, and the fixed plate 72 is driven up and down by a driving member 71 (the fixed plate 72 and the driving member 71 constitute a driving mechanism 7, which is used to drive the first upper mold group 3 and the second upper mold group to synchronously approach or move away from the first lower mold group 1 and the second lower mold group, so as to synchronously realize the punching, cutting and stamping and bending of the metal long thin plate), the first lower mold group 1 and the second lower mold 5 are both supported by a support plate 8, and the punching device, the first transfer device 10 and the stamping and bending device are arranged in a U shape;

[0061] Specifically, the second transfer device includes a mechanical arm (the specific structure is not shown in the figure), a support rod 11 and a material taking component 12. A plurality of material taking components 12 (suction cups can be used) are linearly and equidistantly distributed on the support rod 11. The number of material taking components 12 is set to correspond to the number of the second lower molds 5, so that the metal long thin plate on each second lower mold 5 can be synchronously transferred to the next second lower mold 5 in sequence (transfer from right to left is shown in the figure). The second transfer device is a relatively conventional driving principle, which will not be described in detail here.

[0062] The first transfer device 10 here includes a horizontal drive structure (which can be a cylinder), a vertical drive structure (which can be a cylinder), (the subsequent rotation drive structure can be a motor) and an adsorption structure (specifically, it can be the same as the material taking component 12, both are set as suction cups). After the cut metal long strip thin plate is adsorbed by the adsorption structure, the horizontal drive structure, the vertical drive structure, and the subsequent rotation drive structure cooperate to automatically transfer the metal long strip thin plate to the second lower mold 5 where the distance from the highest point of the protrusion 51 to the top surface of the second lower mold 5 is the smallest;

[0063] Here, 7 second lower molds 5 are taken as an example, and the distance from the highest point of the protrusion 51 on each second lower mold 5 that is linearly equidistantly distributed to the top surface of the second lower mold 5 gradually increases by 0.5 mm. In conjunction with the punching method of the subsequent embodiment 1, at this time, each second lower mold 5 is vertically arranged with the first lower mold assembly 1. Therefore, after the first transfer device 10 grabs the semi-finished handle on the discharge plate 14, it needs to select 90 degrees and then transfer it to the second lower mold 5 where the distance from the highest point of the protrusion 51 to the top surface of the second lower mold 5 is the smallest;

[0064] By setting the punching equipment, the first transfer equipment 10 and the stamping and bending equipment into a U shape, continuous and uninterrupted operation can be achieved through the transfer of the first transfer equipment 10. Compared with the existing punching and bending step-by-step work, it not only avoids the trouble of gathering materials after punching and then transferring them for bending, but also improves efficiency. At the same time, compared with the existing linear continuous stamping die, although the present invention adds the first transfer equipment 10, the punching equipment, the first transfer equipment 10 and the stamping and bending equipment are set into a U shape, and the structural position layout is more reasonable. The space occupied by the equipment is reasonably arranged to avoid the equipment being too long to be well placed in the factory building, thereby realizing continuous and uninterrupted punching, cutting and stamping and bending of long metal strips and thin plates.

[0065] Injection molding equipment (not shown in the figure) is also required to be used to respectively injection-mold and wrap the first injection molding part and the second injection molding part on the outer surface of the clamping unit and the connecting unit facing one end and the other end of the semi-finished handle part, so as to obtain a finished handle part. The second injection molding part is made of nylon material, and the first injection molding part is made of silicone material. The injection molding equipment includes a third lower mold and a third upper mold. The third lower mold is provided with an injection molding positioning column adapted to the circular punching hole, which is used to quickly position the semi-finished handle part on the third lower mold.

[0066] Here, the semi-finished handle portion obtained by bending can also be rotated to the third lower mold by setting a third transfer device to realize automatic material transportation. By wrapping the first injection molded portion and the second injection molded portion on the outer surfaces of both ends of the clamping unit of the semi-finished handle portion, the first injection molded portion can be held more comfortably when held by a person, and the metal heat conduction can be prevented from scalding the hand when the clip is clamping some high-temperature objects. By setting the second injection molded portion as the clamping head part of the clip, the metal clamping head can be prevented from rusting, thereby avoiding food contamination and food safety problems.

[0067] The punching holes 2 also include a plurality of injection molding anti-slipping fixing holes. Through the cooperation of the injection molding anti-slipping fixing holes on the first lower mold assembly 1 and the corresponding punching pieces 4 on the first upper mold assembly 3, a plurality of injection molding positioning punching holes are punched out on the clamping portion of the flat metal long thin plate. After the clamping unit of the semi-finished handle portion is injection molded to wrap the first injection molding portion and the second injection molding portion, the injection molding positioning punching holes and the stamping positioning punching holes are filled with nylon or silicone.

[0068] After the injection molding work is completed, the injection molding positioning punch and the stamping positioning punch are filled with nylon or silicone, and the first injection molding part and the second injection molding part will wrap and hide the stamping positioning punch and the injection molding positioning punch. At the same time, when the stamping positioning punch and the injection molding positioning punch are filled with nylon or silicone, the first injection molding part and the second injection molding part can be ensured to be more stably located on the clamping unit of the semi-finished handle part to prevent them from falling off the outer surface of the finished handle part.

[0069] like Figure 6 As shown, the wall thickness between two adjacent punching holes 2 is not less than 8mm. When the distance between any two punching locations of the circular punching hole, the arc-shaped cutting surface, the stamping positioning punching hole and the injection positioning punching hole is less than 8mm, the two punching locations are punched out twice;

[0070] By setting the distance between the inner walls of each punching hole 2 to not be less than 8 mm, the punching work is performed in multiple times to avoid the problem that the tension cannot be eliminated due to the small wall thickness of two adjacent punching holes 2 during one punching and cutting process, thereby avoiding the first lower die set 1 from being broken during punching and cutting;

[0071] like Fig. 9As shown, when the punching equipment is used to punch (punch and cut) the stainless steel sheet material strip, the punching location includes a rivet punching hole, a circular punching hole, a plurality of positioning punching holes (including a first positioning punching hole, a second positioning punching hole, a third positioning punching hole, a fourth positioning punching hole and a fifth positioning punching hole, which can all be injection positioning punching holes, and the third positioning punching hole can be set as a stamping positioning punching hole) and an arc-shaped cutting surface;

[0072] Here, the length of the stainless steel sheet strip conveyed by the three-in-one feeder is set to 274mm each time (this length is the length of the stainless steel long sheet plus the length of the cut waste, that is, Fig. 9 Before processing, the stainless steel strip is Fig. 9 After the processing shown in the figure), the following are two examples of punching methods:

[0073] Embodiment 1: Figure 6 As shown, the first lower die set 1 includes adjacent first lower die units 101 and second lower die units 102 (the device requires a longer first lower die set 1 due to the increased number of punching times. To facilitate the production and transportation of the first lower die set 1, the first lower die unit 101 and the second lower die unit 102 are combined here), and the punching hole 2 includes a cutting hole 28, a circular hanging hole 26, a first positioning hole 21 and a second positioning hole 22. The circular hanging hole 26 and the first positioning hole 21 are located on the first lower die unit 101, and the cutting hole 28 and the second positioning hole 22 are located on the second lower die unit 102;

[0074] The punching hole 2 further includes a third positioning hole (stamping and bending positioning hole 23), a fourth positioning hole 24, a fifth positioning hole 25 and a rivet hole 27. The third positioning hole (stamping and bending positioning hole 23), the fourth positioning hole 24 and the fifth positioning hole 25 start from the top surface of the first lower mold unit 101 in sequence along the length direction of the first lower mold unit 101. The rivet hole 27 is located on the second lower mold unit 102. The third positioning hole (stamping and bending positioning hole 23), the fourth positioning hole 24 and the fifth positioning hole 25 are located between the circular hanging hole 26 and the first positioning hole 21. The rivet hole 27 is located between the second positioning hole 22 and the cutting hole 28.

[0075] Since the minimum distance between the first positioning punching hole and the second positioning punching hole and between the circular punching hole and the cutting surface of the semi-finished handle after processing is less than 8mm, four punchings and one cutting are performed here. Fig.10 As shown, (for the convenience of display, the figure here is from top to bottom, and the dotted lines in the figure are the punching and cutting points each time);

[0076] Specifically, Figure 2 , Figure 6 and Fig.10As shown, the material strip is fed by the three-in-one feeder to the first lower die unit 101, and when the first positioning punching hole to be opened is aligned with the first positioning hole 21, the driving mechanism 7 is adjusted to drive the first upper die set 3 to move downward, so that a first punching rod 41 processes the first positioning hole 21 in the material strip, thereby realizing the first punching;

[0077] After that, the material strip is fed 274 mm by the three-in-one feeder. At this time, the third positioning punching hole, the fourth positioning punching hole and the fifth positioning punching hole correspond to the third positioning hole (stamping and bending positioning hole 23), the fourth positioning hole 24 and the fifth positioning hole 25 respectively. By adjusting the driving mechanism 7, it drives the first upper die set 3 to move downward, so that the three first punching rods 41 process the third positioning hole (stamping and bending positioning hole 23), the fourth positioning hole 24 and the fifth positioning hole 25 in the material strip, realizing the second punching. At the same time, the subsequent material strips are synchronously punched for the first time.

[0078] Then the material strip continues to be fed by the three-in-one feeder for 274 mm. At this time, the circular hanging hole 26 and the second positioning hole 22 correspond to the circular punching hole and the second positioning punching hole respectively. By adjusting the driving mechanism 7, it drives the first upper die set 3 to move downward, so that a second punching rod 42 and a first punching rod 41 process the circular hanging hole 26 and the second positioning hole 22 on the material strip, realizing the third punching. At the same time, the subsequent material strips are synchronously punched for the first and second punching operations;

[0079] Then, the material strip is fed 274 mm by the three-in-one feeder. At this time, the rivet holes 27 (two are provided here) correspond to the rivet punching holes. By adjusting the driving mechanism 7, the first upper die set 3 is driven to move downward, so that the first punching rod 41 processes the rivet punching holes on the material strip, realizing the fourth punching. At the same time, the subsequent material strips are punched for the first, second and third times simultaneously.

[0080] Finally, the material strip is fed 274 mm by the three-in-one feeder. At this time, one side of the cutting hole 28 is adapted to correspond to the cutting surface. By adjusting the driving mechanism 7, it drives the first upper die set 3 to move downward, so that the punching block 43 cuts the material strip. At the same time, the subsequent material strips are punched for the first time, the second time, the third time and the fourth time synchronously.

[0081] Subsequently, the material strip is fed 274 mm each time through the three-in-one feeding mechanism, thereby realizing continuous and uninterrupted production and processing of the semi-finished handles. Moreover, through this equipment, although it is longer than the existing processing mold, the wall thickness of each punching hole 2 on the first lower mold group 1 can be made greater than 8 mm, and the step-by-step continuous and uninterrupted punching work can be realized, thereby avoiding the existing problem that the tension cannot be eliminated due to the small wall thickness of two adjacent punching holes 2 during one punching and cutting process, thereby avoiding the first lower mold group 1 from being broken during punching and cutting.

[0082] It should be noted that before each conveyance of the material strip, the driving mechanism 7 is adjusted to drive the first upper die set 3 to move upward.

[0083] Embodiment 2: Fig.11 As shown, there are two punching and one cutting here (for the convenience of display, the figure here is from top to bottom), and the specific mold diagram is not drawn;

[0084] Specifically, when the three-in-one feeder conveys the material strip to the first lower die set 1, and the first positioning punching hole, the third positioning punching hole, the fourth positioning punching hole and the fifth positioning punching hole correspond to the first positioning hole 21, the third positioning hole (stamping and bending positioning hole 23), the fourth positioning hole 24 and the fifth positioning hole 25 respectively, the driving mechanism 7 is adjusted to drive the first upper die set 3 to move downward, so that the four first punching rods 41 process the material strip into the first positioning hole 21, the third positioning hole (stamping and bending positioning hole 23), the fourth positioning hole 24 and the fifth positioning hole 25, thereby realizing the first punching;

[0085] After that, the material strip is fed 274 mm by the three-in-one feeder. At this time, the circular hanging hole 26, the second positioning hole 22 and the rivet hole 27 (two are provided here) correspond to the circular punching hole, the second positioning punching hole and the rivet punching hole respectively. By adjusting the driving mechanism 7, it drives the first upper die set 3 to move downward, so that the first punching rod 41 and the second punching rod 42 process the material strip into the second positioning hole 22, the rivet hole 27 and the circular hanging hole 26, and realize the second punching. At the same time, the subsequent material strips are synchronously punched for the first time.

[0086] Finally, the material strip is fed 274 mm by the three-in-one feeder. At this time, one side of the cutting hole 28 is adapted to correspond to the cutting surface. By adjusting the driving mechanism 7, it drives the first upper die set 3 to move downward, so that the punching block 43 cuts the material strip. At the same time, the subsequent material strips are punched for the first time and the second time synchronously.

[0087] The specific punching times and methods are not described in detail here. It is only necessary to ensure that the wall thickness between adjacent punching holes 2 on the first lower module 1 is not less than 8 mm.

[0088] like Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, a limiting mechanism 6 is provided on the surface facing the first lower die set 1 and the first upper die set 3, and the limiting mechanism 6 includes a first limiting assembly, and the first limiting assembly includes a plurality of groups of limiting parts and limiting holes 64, each group of limiting parts includes two elastic limiting rods 62, and the elastic limiting rods 62 are provided on the top surface of the first lower die set 1, and an annular groove is provided on the periphery of the elastic limiting rods 62, and the distance between the annular grooves is adapted to the width of the material strip, and a limiting hole 64 adapted to the elastic limiting rods 62 is provided on the bottom surface of the first upper die set 3, which is used to accommodate the upper part of the annular groove of the elastic limiting rods 62, and when the first upper die set 3 moves downward, the elastic limiting rods 62 are squeezed, and the elastic limiting rods 62 move downward, so that the material strip fits with the top surface of the first lower die set 1, thereby facilitating the punching work;

[0089] By providing an elastic limiting rod 62 with an annular groove, the distance between the annular grooves is adapted to the width of the material belt, so that the material belt can be conveyed between the two annular grooves, thereby ensuring stable conveyance of the material belt and preventing left and right deviation when the three-in-one feeder feeds the material.

[0090] like Figure 6 , Figure 7 and Figure 8 As shown, the limiting mechanism 6 also includes a second limiting assembly, which includes a plurality of limiting blocks 63 and limiting grooves 61. The limiting blocks 63 are arranged on the bottom surface of the first upper mold assembly 3 along the conveying direction of the material belt. The limiting blocks 63 are provided with grooves adapted to the width of the material belt. The top surface of the first lower mold assembly 1 is provided with limiting grooves 61 adapted to the limiting blocks 63.

[0091] When there are two groups of punching holes 2 here, two corresponding grooves are also provided. When the driving mechanism 7 drives the first upper mold group 3 to move downward, the first upper mold group 3 drives the limit block 63 to move, and the groove on the limit block 63 limits the material strip, thereby ensuring that subsequent punching can be more precise, and further preventing the material strip from shifting left and right when punching the material strip.

[0092] The last four second lower molds 5 are provided with bending grooves 52, each two forming a group, the depths of the two groups of bending grooves 52 are 0.8mm-1mm and 3.5mm-3.7mm respectively. After the two groups of bending grooves 52 are stamped and bent, the angle between the plane where the connecting part of the metal long sheet is away from the end of the clamping part and the section of the deepest point of the bending groove 52 is 3°-4° (such as Fig.12 A) and 8°-9° (as shown in Fig.12 B) shown in ;

[0093] When 7 second lower dies 5 are set here, the depth of the bending groove 52 of the fourth and fifth second lower dies 5 is set to 0.9mm, the depth of the bending groove 52 of the sixth and seventh second lower dies 5 is 3.68mm, the bending grooves 52 of the fourth and sixth second lower dies 5 are both pre-pressing stations, and the bending grooves 52 of the fifth and sixth second lower dies 5 ensure that the predetermined stamping and bending effect can be achieved. Since the connecting part of the metal long thin plate is bent in the width direction, cracking will not easily occur, so there is no need to use 5-9 stamping and bending like the clamping part.

[0094] The present invention forms a complete processing technology of metal clips by combining three-in-one feeding equipment, punching equipment, stamping and bending equipment and injection molding equipment. The processing technology is closely linked and highly automated. When the punching equipment cuts the flattened metal strip to obtain a long metal sheet, circular punching holes required for subsequent hanging and riveting holes required for riveting are punched out in advance on the long metal sheet, which facilitates the rapid and accurate positioning of the punching positioning punching holes placed on the second lower mold 5 for subsequent punching and bending, and the injection molding positioning punching holes that allow the first injection molding part and the second injection molding part to be stably located on the clamping unit of the semi-finished handle part. The reasonable position arrangement of the punching holes 2 on the first lower mold assembly 1 ensures that the distance between the inner walls of the punching holes 2 will not be less than 8 mm. The punching work is performed in multiple times to avoid the problem that the tension cannot be eliminated due to the excessively small wall thickness of two adjacent punching holes 2 during one punching and cutting process, thereby avoiding the first lower mold assembly 1 from being broken during punching and cutting.

[0095] In the subsequent stamping and bending, multiple step-by-step stamping and bending are used to disperse the stress of the material during the deformation process, reduce stress concentration and avoid cracks caused by excessive strain. Multiple stamping allows more precise control of the strain rate of each stamping, which helps to improve the plasticity of the material and reduce damage accumulation. Compared with the existing production process, it can not only effectively solve the problem of product molding cracking in the prior art and improve the product molding quality, but also has fewer process steps, less labor and high production efficiency.

[0096] After the injection molding work is completed, the injection molding positioning punching holes and the stamping positioning punching holes are filled with nylon or silicone, and the first injection molding part and the second injection molding part will wrap and hide the stamping positioning punching holes and the injection molding positioning punching holes, so that the outer surface of the final finished handle part will not have any extra punching defects. At the same time, when the stamping positioning punching holes and the injection molding positioning punching holes are filled with nylon or silicone, it can ensure that the first injection molding part and the second injection molding part are more stably located on the clamping unit of the semi-finished handle part to prevent them from falling off from the outer surface of the finished handle part.

[0097] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal clip automatic cold forming process, characterized in that: It is necessary to use a stamping and bending device, a punching and shearing device, a three-in-one feeding device, a first transfer device (10) and a second transfer device. The stamping and bending device comprises a second lower die set and a second upper die set. The second lower die set comprises 5 to 9 second lower dies (5) which are linearly and equidistantly distributed. The top surface of each second lower die (5) is provided with a long strip-shaped raised portion (51) along its length direction. The top surface of the raised portion (51) is bent in an arc shape downward from the middle position to the edges around it. The distance from the highest point of the raised portion (51) on each of the linearly and equidistantly distributed second lower dies (5) to the top surface of the second lower die (5) gradually increases. , at least two of the second lower molds (5) have arc-shaped bending grooves (52) on their top surfaces along the width direction thereof, the bending grooves (52) are perpendicular to and do not contact the raised portion (51), the second upper mold set comprises 5-9 second upper molds (9) which are linearly and equidistantly distributed, each of the second upper molds (9) is located directly above the second lower mold (5), the second upper mold (9) directly above each second lower mold (5) is provided with a recessed portion (91) adapted to the raised portion (51), and the bottom surface of the second upper mold (9) corresponding to the second lower mold (5) having the bending grooves (52) is provided with a protruding portion (92); The three-in-one feeding device comprises a stainless steel coil rack, a flattening machine and a feeder, the punching device comprises a first upper die set (3) and a first lower die set (1), each second lower die set (5) is vertically arranged with respect to the first lower die set (1), and the production process of a flat metal long thin plate comprises: under the traction of the feeder, a stainless steel SUS430 metal strip with a Vickers hardness value in the range of 220HV-240HV wound on the stainless steel coil rack is pulled through the flattening machine for flattening, and then equidistantly transported to the first upper die set (3), and cut through the punching device, thereby obtaining a flat metal long thin plate; The first transfer device (10) is used to automatically transfer the metal long thin plate obtained by punching to the second lower mold (5). The first transfer device (10) comprises a horizontal drive structure, a vertical drive structure, a rotation drive structure and an adsorption structure. After the cut metal long thin plate is adsorbed by the adsorption structure, the horizontal drive structure, the vertical drive structure and the subsequent rotation drive structure cooperate to automatically transfer the metal long thin plate to the second lower mold (5) where the distance between the highest point of the protrusion (51) and the top surface of the second lower mold (5) is the smallest. The second transfer device is used to transfer the metal long thin plates one by one to each second lower mold (5), the punching device and the punching and bending device are arranged in parallel, the first upper mold group (3) and the second upper mold (9) are fixed on the same fixed plate (72), and the fixed plate (72) is driven by a driving member (71) to move up and down, and the punching device, the first transfer device (10) and the punching and bending device are arranged in a U shape; The clip comprises two semi-finished handle parts, each of which comprises a connecting unit and a clamping unit, the two clamping units facing each other are concave from all sides to the center, the two connecting units facing each other are gradually bent away from the middle to both ends, and the end of the connecting unit away from the clamping unit is straight-edged, and the cold forming process comprises the following steps: One: a flat metal long thin plate is divided into a connecting portion and a clamping portion, and the flat metal long thin plate is placed on a second lower mold (5) where the distance between the highest point of the protrusion (51) and the top surface of the second lower mold (5) is the smallest, and the first stamping and bending is performed, wherein the clamping portion is directly opposite to the protrusion (51) on the second lower mold (5), so that the clamping portion of the flat metal long thin plate is concave, and after being stamped by each second lower mold (5) and the second upper mold (9) thereon, the degree of concavity of the clamping portion of the metal long thin plate is deepened by 0.4mm-0.7mm each time; Second, the metal long thin plates are sequentially transferred to the remaining second lower dies (5) which are linearly and equidistantly distributed for gradual stamping and bending, so that the depression of the clamping portion of the metal long thin plates gradually deepens until the depression of the clamping portion of the metal long thin plates matches the depression of the clamping unit of the semi-finished handle portion, and at this time, the connecting portion of the metal long thin plates is bent at one end connected to the clamping portion through the bending groove (52) and the protruding portion (92), until the bending degree of one end of the connecting portion of the metal long thin plates matches the bending degree of the connecting unit of the semi-finished handle portion, thereby obtaining a semi-finished handle portion; Three: bend the straight sides of the connection units of the two semi-finished handle parts, fit them together and rivet them together. At this time, there is a gap between the clamping units of the two semi-finished handle parts, and a complete clip is obtained.

2. The automatic cold forming process for metal clips according to claim 1, characterized in that: The top surface of the first lower die set (1) is provided with at least one group of punching holes along its length direction, each group of the punching holes comprises a plurality of punching holes (2), the first upper die set (3) is located directly above the first lower die set (1), the first upper die set (3) is provided with punching pieces (4) adapted and corresponding to the punching holes (2), the punching holes (2) comprising cutting holes (28) and rivet holes (27); The cold forming process also includes: by means of the cutting holes (28) and the rivet holes (27) on the first lower die set (1) cooperating with the matching and corresponding punching pieces (4) on the first upper die set (3), the connecting portion of the metal long sheet away from the clamping portion is cut into an arc-shaped cutting surface, and a rivet hole is punched out on the connecting portion of the flat metal long sheet, so as to be used for subsequent riveting to fit and rivet the connecting units of the two semi-finished handle parts.

3. The automatic cold forming process for metal clips according to claim 2, characterized in that: The punching holes (2) further include a circular hanging hole (26) and at least one punching and bending positioning hole (23); the second lower die (5) is provided with a punching and bending positioning column adapted to the punching and bending positioning hole (23); the circular hanging hole (26) and the punching and bending positioning hole (23) on the first lower die set (1) cooperate with the corresponding punching piece (4) on the first upper die set (3) to punch out a circular punching hole on the connecting portion of the flat metal long strip thin plate, and punch out a punching and positioning punching hole on the clamping portion of the flat metal long strip thin plate.

4. The automatic cold forming process for metal clips according to claim 3, characterized in that: Injection molding equipment is also required to inject and wrap the first injection molding part and the second injection molding part on the outer surfaces of the clamping unit and the connecting unit facing one end and the other end of the semi-finished handle part, respectively, so as to obtain a finished handle part. The second injection molding part is made of nylon material, and the first injection molding part is made of silicone material. The injection molding equipment includes a third lower mold and a third upper mold. The third lower mold is provided with an injection molding positioning column adapted to the circular punching hole, which is used to position the semi-finished handle part on the third lower mold.

5. The automatic cold forming process for metal clips according to claim 4, characterized in that: The punching holes (2) also include a plurality of injection molding anti-slipping fixing holes. Through the cooperation of the injection molding anti-slipping fixing holes on the first lower mold group (1) and the corresponding punching pieces (4) on the first upper mold group (3), a plurality of injection molding positioning punching holes are punched out on the clamping part of the flat metal long thin plate. After the clamping unit of the semi-finished handle part is injection molded to wrap the first injection molding part and the second injection molding part, the injection molding positioning punching holes and the stamping positioning punching holes are filled with nylon or silicone.

6. The metal clip automated cold forming process according to claim 5, characterized in that: The wall thickness between two adjacent punching holes (2) is not less than 8 mm. When the distance between any two punching locations of the circular punching hole, the arc-shaped cutting surface, the punching positioning punching hole and the injection positioning punching hole is less than 8 mm, the two punching locations are punched out twice.

7. The automatic cold forming process for metal clips according to claim 6, characterized in that: The last four second lower molds (5) are provided with bending grooves (52), two in each group, and the depths of the two groups of bending grooves (52) are 0.8mm-1mm and 3.5mm-3.7mm respectively. After being stamped and bent by the two groups of bending grooves (52), the angles between the plane where the connecting part of the metal long thin plate is located away from one end of the clamping part and the cross-section of the deepest point of the bending groove (52) are 3°-4° and 8°-9°.

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