Three-step forming cold extrusion process method for firing pin and continuous cold extrusion forming die

Abstract

The application provides a three-step forming cold extrusion process method and a forming die for a firing pin, which comprises the following steps: pre-cutting, pre-cutting two adjacent part material sheets apart by using a pre-cutting punch and a pre-cutting die; pre-forming, pressing the required material of the part into a material storage hole by using a pre-forming punch and a pre-forming die, and extruding the excess material into the extrusion area of the next working step; rough forming, rough forming of the part is completed by using a rough forming punch and a rough forming die; trimming the excess material, the material extruded in the pre-forming and rough forming steps is cut off by using a trimming punch and a trimming die, so that the edge of the material is ensured to be free of cracks; fine forming, fine forming of the steel strip is performed by using a fine forming punch and a fine forming die. The three-step forming cold extrusion process method breaks through the bottleneck in the cold extrusion forming process of small high-strength, high-precision and special-shaped metal parts, significantly improves the forming efficiency and improves the forming quality. The forming quality of the firing pin obtained by the forming die is high.

Description

Technical Field

[0001] This application relates to the field of firing pin forming technology, and more specifically, to a three-step cold extrusion process for firing pins. It also relates to a continuous cold extrusion die suitable for the aforementioned three-step cold extrusion process for firing pins. Background Technology

[0002] For cold extrusion forming of small, high-strength, high-precision metal parts with special shapes, such as firing pins, the material removal method is not feasible due to the small size and special geometry of the parts. Currently, the commonly used cold extrusion method is difficult to form, or even impossible, because the raw material undergoes relatively large plastic deformation during extrusion. At the same time, the small size of the parts results in insufficient rigidity of the forming part of the die, leading to short life of cold extrusion dies and frequent maintenance. Summary of the Invention

[0003] This application provides a three-step cold extrusion process for firing pins. This three-step cold extrusion process addresses the bottlenecks in the cold extrusion forming of small, high-strength, high-precision metal parts with special shapes, significantly improving forming efficiency and quality. This application also provides a continuous cold extrusion die suitable for the aforementioned three-step cold extrusion process for firing pins.

[0004] This application provides a three-step cold extrusion process for firing pins, including the following steps:

[0005] Pre-cutting involves using a pre-cutting punch and a pre-cutting die to pre-cut two adjacent parts into separate pieces.

[0006] Preforming involves using a preforming punch and a preforming die to press the required material into the storage cavity and extrude excess material into the extrusion area of ​​the next step.

[0007] Rough forming: using rough forming punches and rough forming dies to complete the rough forming of parts;

[0008] Trim excess material by using a trimming punch and trimming die to remove the material extruded in the preforming and rough forming steps, ensuring that there are no cracks on the material edges.

[0009] Precision forming involves using precision forming punches and precision forming dies to precision form steel strips.

[0010] In some embodiments, before the step of pre-cutting two adjacent part sheets apart using a pre-cutting punch and a die, the method further includes:

[0011] The quantity of raw materials for cold extrusion is determined by calculation, and the size of the sheet is designed. This step separates the materials required for two adjacent parts into different shapes.

[0012] In some embodiments, the step of pressing the required material for the part into the storage cavity using a pre-forming punch and a pre-forming die, and extruding excess material into the extrusion area of ​​the next step, includes:

[0013] By using computer simulation data and based on the principle of equal volume change, the shape, size, position, and overflow gap of the material storage cavity are rationally designed on the die.

[0014] In some embodiments, the step of completing the rough forming of the part using a rough forming punch and a rough forming die includes: according to the geometric dimensions of the part, following the principle of equal volume change, enlarging the fillet radius and cavity size of the forming part of the die.

[0015] In some embodiments, the step of precision forming the steel strip using a precision forming punch and a precision forming die is designed according to the dimensional requirements of the forming part to ensure that the part meets the product requirements.

[0016] The three-step cold extrusion process for firing pins provided in this application has the following technical advantages:

[0017] 1. This process method is based on the material flow mechanism of metal materials under cold extrusion. It uses a three-step forming method to reasonably design the geometric dimensions of the forming parts of the mold in each step, so that the raw materials required for the next step are pressed into the easily deformable area of ​​the next step in the first step, thereby making the material flow in the next step smooth.

[0018] 2. By taking a unique approach and adopting a three-step forming method, the number of steps in the continuous cold extrusion forming die is rationally selected while minimizing the impact of work hardening on the material's fluidity during the cold extrusion process. This ensures the geometric shape requirements of the parts and significantly improves the product yield.

[0019] 3. The three-step forming method simplifies the design of cold extrusion dies, improves the machinability of die parts, improves the stress state of core die parts, and significantly extends the life of cold extrusion dies.

[0020] This application effectively solves the problem of difficult design of high-precision cold extrusion parts molds, and at the same time greatly improves the mold design and manufacturing efficiency.

[0021] Furthermore, this application also provides a continuous cold extrusion forming die for use in the above-mentioned three-step forming cold extrusion process for firing pins, comprising:

[0022] The mold frame is connected to the punch press;

[0023] The guiding mechanism provides guidance for the movement of the conveyor belt;

[0024] The positioning mechanism includes an upper fixing plate installed at the bottom of the mold frame, a process hole punch penetrating the mold frame and the upper fixing plate, a guide pin installed at the top of the process hole punch, and a lower fixing plate.

[0025] Demolding mechanism;

[0026] The forming mechanism has pre-cutting punches and pre-cutting dies coaxially distributed, pre-forming punches and pre-forming dies coaxially distributed, rough forming punches and rough forming dies coaxially distributed, trimming punches and trimming dies coaxially distributed, and fine forming punches and fine forming dies coaxially distributed.

[0027] The blanking mechanism includes blanking punches and blanking dies that are coaxially distributed.

[0028] The continuous cold extrusion forming die provided in this application adopts the above-mentioned three-step cold extrusion process for forming firing pins. It is used to stamp firing pins, and the resulting firing pins have high forming quality and high forming effect, which significantly improves the processing and forming efficiency of firing pins. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 A process flow diagram of the three-step cold extrusion process for firing pins provided in this application;

[0031] Figure 2 A front view of a part drawing obtained by applying the three-step cold extrusion process for firing pins provided in this application;

[0032] Figure 3 A cross-sectional view of a part drawing obtained by applying the three-step cold extrusion process for firing pins provided in this application;

[0033] Figure 4 for Figure 3 Enlarged view of part A in the middle;

[0034] Figure 5 This is a cross-sectional view of the continuous cold extrusion die provided in this application;

[0035] Figure 6 for Figure 5 Schematic diagram of the pre-cutting punch;

[0036] Figure 7 for Figure 5 A schematic diagram of the pre-cut die;

[0037] Figure 8 for Figure 5 Schematic diagram of the pre-forming punch;

[0038] Figure 9 for Figure 5 Schematic diagram of the pre-forming die;

[0039] Figure 10 for Figure 5 Schematic diagram of a medium-coarse forming punch;

[0040] Figure 11 for Figure 5 Schematic diagram of a medium-rough forming die;

[0041] Figure 12 for Figure 5 Schematic diagram of the center-side punch;

[0042] Figure 13 for Figure 5 Schematic diagram of the trimming die;

[0043] Figure 14 for Figure 5 Schematic diagram of a precision forming punch;

[0044] Figure 15 for Figure 5 A schematic diagram of a precision forming die.

[0045] Among them, 1-mold frame, 2-upper fixed plate, 3-process hole punch, 4-guide pin, 5-pre-cut punch, 6-pre-forming punch, 7-rough forming punch, 8-trimming punch, 9-precision forming punch, 10-blank punch, 11-blank die, 12-precision forming die, 13-trimming die, 14-rough forming die, 15-pre-forming die, 16-pre-cut die, 17-lower fixed plate, 18-guide mechanism, 19-demolding mechanism, 20-process hole die. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] Please refer to Figures 1 to 4 , Figure 1 A process flow diagram of the three-step cold extrusion process for firing pins provided in this application; Figures 2 to 4 A part drawing obtained by applying the three-step cold extrusion process for firing pins provided in this application.

[0048] like Figure 1 As shown. This application provides a three-step cold extrusion process for firing pins, comprising the following steps:

[0049] Step 1: Pre-cutting. Use the pre-cutting punch 5 and the pre-cutting die 16 to pre-cut two adjacent parts into separate pieces.

[0050] Step 2: Pre-forming. The pre-forming punch 6 and pre-forming die 15 are used to press the material required for the part into the storage cavity, and the excess material is extruded into the extrusion area of ​​the next step.

[0051] Step 3: Rough forming, using the rough forming punch 7 and the rough forming die 14 to complete the rough forming of the part;

[0052] Step 4: Trim excess material. Use the trimming punch 8 and trimming die 13 to cut off the material extruded in the preforming and rough forming steps, ensuring that there are no cracks on the material edges.

[0053] Step 5: Precision forming, using the precision forming punch 9 and precision forming die 12 to perform precision forming on the steel strip.

[0054] In the pre-cutting process of step one, the mold composed of the pre-cutting punch 5 and the pre-cutting die 16 separates the adjacent two parts so that they can be formed.

[0055] In the preforming process of step two, the combined mold consisting of the preforming punch 6 and the preforming die 15 presses the material required for the part into the storage cavity, and the excess material is extruded into the extrusion area of ​​the next step.

[0056] In the third step of the rough forming process, the combined mold consisting of the rough forming punch 7 and the rough forming die 14 completes the rough forming of the part. This step completes the rough forming of the part.

[0057] In the fourth step, excess material is trimmed. A combined die consisting of trimming punch 8 and trimming die 13 removes the material extruded in the first two steps (i.e., preforming and rough forming). During the preforming and rough forming processes, the raw material is compressed. During the extrusion of excess material, due to the large plastic deformation of the material, cracks are easily generated at the edges of the extruded material. Although these cracks are small, they create stress concentration points on the part. Consequently, during the extrusion process in the finishing step, the cracks will extend towards the center of the part, causing the part to be scrapped. Therefore, this step must remove the material extruded in the first two steps to ensure that there are no cracks at the material edges.

[0058] In the fifth step of precision forming, the combined mold consisting of precision forming punch 9 and precision forming die 12 completes the precision forming of the steel strip. This step is designed entirely according to the dimensional requirements of the part forming part, ensuring that the part meets the product requirements.

[0059] The part drawing obtained using the above method is as follows: Figures 2 to 4 As shown.

[0060] The three-step cold extrusion process for firing pins provided in this application is particularly suitable for cold extrusion forming of small, high-strength, high-precision metal parts with special shapes. For parts made of carbon tool steel, such as T10A, which suffer from severe work hardening during extrusion, simply increasing the number of forming steps yields minimal results. This application enables the rational design of continuous cold extrusion forming dies.

[0061] Before step one: using the pre-cutting punch 5 and the pre-cutting die 16 to pre-cut the two adjacent parts into separate pieces, the process also includes the following steps: calculating and determining the amount of raw material for cold extrusion, designing the size of the pieces, and using this step to separate the required materials for the two adjacent parts into separate pieces.

[0062] Step 2: Using the pre-forming punch 6 and the pre-forming die 15, the material required for the part is pressed into the storage cavity. Before the excess material is extruded into the extrusion area of ​​the next step, the following steps are taken: using computer simulation data and based on the principle of equal volume change, the shape, size, position and overflow gap of the storage cavity are reasonably designed on the die.

[0063] By utilizing computer-aided design and the principle of equal volume change of metal materials under extrusion, the material storage cavity and forming size are rationally designed on the die to avoid long-distance material flow in order to minimize the amount of material flow (deformation) and reduce the resistance of excess material overflow. This step is to press the material required for the part into the storage cavity and extrude the excess material into the extrusion area of ​​the next step, while also significantly improving the die life.

[0064] Step 3: The rough forming of the part is completed by using the rough forming punch 7 and the fine forming die 12. This also includes: according to the geometric dimensions of the part, following the principle of equal volume change, the radius of the rounded corners and the size of the cavity of the forming part of the die are enlarged.

[0065] This step requires strictly adhering to the principle of equal volume change based on the geometric dimensions of the part, and appropriately enlarging the radius of the rounded corners and the size of the cavity in the forming part of the mold. This ensures smooth flow of the raw material when it is squeezed, and greatly improves the mold's processability and lifespan. This step is to complete the rough forming of the part.

[0066] In the trimming process of step four, the trimming of excess material is accomplished by the trimming punch 8 and the trimming die 13. Due to the extrusion of the raw material during preforming and rough forming, excess material is extruded. Simultaneously, due to the significant plastic deformation of the extruded material, cracks easily form at the edges. Although these cracks are small, they create stress concentration points on the part, which can then extend towards the center of the part during the finishing process, rendering the part unusable. Therefore, this step removes the material extruded in the first two steps to ensure that the material edges are free of cracks.

[0067] In step five, during the precision forming process of the steel strip using the precision forming punch 9 and precision forming die 12, the design should be carried out entirely according to the dimensional requirements of the forming part to ensure that the part meets the product requirements.

[0068] Since preforming and rough forming designs are critical processes, meticulous theoretical calculations should be performed in order to ensure the accuracy of forming. Then, process experiments should be conducted in conjunction with actual conditions to determine the design scheme.

[0069] This application adopts a three-step forming method, which is a continuous cold extrusion forming process designed for high carbon tool steel (such as T10A). Through three forming stations of pre-forming, rough forming and fine forming, and with the help of two auxiliary stations of pre-cutting and trimming, the parts are finely formed. It also assists in computer-aided design and the principle of equal volume change of metal materials during the extrusion process, so as to rationally design the sheet size and the shape, size and position of the die storage cavity in the forming step.

[0070] Please refer to Figure 5 To the diagram, Figure 5 This is a cross-sectional view of the continuous cold extrusion die provided in this application; Figure 6 for Figure 5 Schematic diagram of the pre-cutting punch; Figure 7 for Figure 5 A schematic diagram of the pre-cut die; Figure 8 for Figure 5 Schematic diagram of the pre-forming punch; Figure 9 for Figure 5 Schematic diagram of the pre-forming die; Figure 10 for Figure 5 Schematic diagram of a medium-coarse forming punch; Figure 11 for Figure 5 Schematic diagram of a medium-rough forming die; Figure 12 for Figure 5 Schematic diagram of the center-side punch; Figure 13 for Figure 5 Schematic diagram of the trimming die; Figure 14 for Figure 5 Schematic diagram of a precision forming punch; Figure 15 for Figure 5 A schematic diagram of a precision forming die.

[0071] In addition, this application also provides a continuous cold extrusion forming die for the above-mentioned three-step forming cold extrusion process for firing pins. The above-mentioned method is mainly realized by a set of continuous cold extrusion dies. The continuous cold extrusion forming die mainly includes: die frame 1, guiding mechanism 18, positioning mechanism, demolding mechanism 19, forming mechanism and blanking mechanism.

[0072] The mold base 1 is the foundation of the entire mold set. It connects to the punch press, ensuring the reciprocating accuracy of the mold during operation. The guiding mechanism 18 is located below the mold base 1, providing guidance for the material strip movement and ensuring it moves according to preset requirements during operation. The positioning mechanism includes an upper fixed plate 2, a process hole punch 3, a guide pin 4, and a lower fixed plate 17. The upper fixed plate 2 is installed at the bottom of the mold base 1. The process hole punch 3 vertically penetrates the mold base 1 and the upper fixed plate 2. The guide pin 4 is installed at the top of the process hole punch 3. The positioning mechanism ensures accurate positioning of the material strip with each forward step.

[0073] The demolding mechanism 19 is horizontally positioned at the lower part of the forming mold. The demolding mechanism 19 ensures that the strip material can be reliably and smoothly removed from the punch.

[0074] The forming mechanism comprises a pre-cutting punch 5, a pre-forming punch 6, a rough forming punch 7, a trimming punch 8, a precision forming punch 9, a precision forming die 12, a trimming die 13, a rough forming die 14, a pre-forming die 15, and a pre-cutting die 16. The pre-cutting punch 5 and the pre-cutting die 16 are coaxially distributed, with the pre-cutting die 16 positioned directly below the pre-cutting punch 5. The pre-forming die 15 is positioned directly below the pre-forming punch 6, and both are coaxially distributed. The rough forming die 14 is positioned directly below the rough forming punch 7, and both are coaxially distributed. The trimming die 13 is positioned directly below the trimming punch 8, and both the trimming punch 8 and the trimming die 13 are coaxially distributed. The forming mechanism ensures that the geometry of the extruded parts meets the requirements. The blanking mechanism comprises a blanking punch and a blanking die, which are coaxially distributed vertically. Blanking is achieved through the blanking punch and the blanking die.

[0075] In addition, the mold also has a process hole punch 3 and a process hole die 20 coaxially distributed. The process hole is processed by punching the process hole die 20 through the process hole punch 3.

[0076] The continuous cold extrusion forming die in this application shall have sufficient strength in its die frame 1, guiding mechanism 18, positioning mechanism, demolding mechanism 19, forming mechanism and blanking mechanism to ensure that the die moves smoothly and reliably in working condition and to ensure service life.

[0077] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0078] The foregoing has provided a detailed description of the three-step cold extrusion process and continuous cold extrusion die for firing pins provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A three-step cold extrusion process for firing pins, characterized in that, Including the following steps: Pre-cutting involves using a pre-cutting punch and a pre-cutting die to pre-cut two adjacent parts into separate pieces. Preforming involves using computer simulation data and based on the principle of equal volume change to rationally design the shape, size, position, and overflow gap of the material storage cavity on the die. The preforming punch and preforming die are used to press the material required for the part into the material storage cavity and extrude the excess material into the extrusion area of ​​the next step. Rough forming: using rough forming punches and rough forming dies to complete the rough forming of parts; Trim excess material by using a trimming punch and trimming die to remove the material extruded in the preforming and rough forming steps, ensuring that there are no cracks on the material edges. Precision forming involves using precision forming punches and precision forming dies to precision form steel strips.

2. The three-step cold extrusion process for firing pins according to claim 1, characterized in that, The steps described are as follows: Before using a pre-cutting punch and die to pre-cut two adjacent parts into separate pieces, the process also includes: The quantity of raw materials for cold extrusion is determined by calculation, and the size of the sheet is designed. This step separates the materials required for two adjacent parts into different shapes.

3. The three-step cold extrusion process for firing pins according to claim 1, characterized in that, The steps described are as follows: Rough forming of parts is accomplished using rough forming punches and rough forming dies, including: according to the geometric dimensions of the parts, following the principle of equal volume change, enlarging the fillet radius and cavity size of the die forming position.

4. The three-step cold extrusion process for firing pins according to any one of claims 1 to 3, characterized in that, The steps are as follows: During the precision forming process of steel strip using a precision forming punch and a precision forming die, the dimensions of the forming part are designed according to the requirements of the part forming part to ensure that the part meets the product requirements.

5. A continuous cold extrusion forming die applied to the three-step forming cold extrusion process for firing pins as described in any one of claims 1 to 4, characterized in that, include: The mold frame (1) is connected to the punch press; The guiding mechanism (18) provides guidance for the movement of the material belt; The positioning mechanism includes an upper fixing plate (2) installed at the bottom of the mold frame (1), a process hole punch (3) penetrating the mold frame (1) and the upper fixing plate (2), a guide pin (4) installed at the top of the process hole punch (3), and a lower fixing plate (17). Demolding mechanism (19); The forming mechanism includes a pre-cutting punch (5) and a pre-cutting die (16) distributed coaxially, a pre-forming punch (6) and a pre-forming die (15) distributed coaxially, a rough forming punch (7) and a rough forming die (14) distributed coaxially, a trimming punch (8) and a trimming die (13) distributed coaxially, and a fine forming punch (9) and a fine forming die (12) distributed coaxially. The blanking mechanism includes a blanking punch (10) and a blanking die (11) that are coaxially distributed.

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