A mold for an electrically powered core rod forming process

Abstract

The utility model discloses a kind of for electric core rod forming process mould, including upper punch, die sleeve, lower punch and core rod, further include the core rod direct drive motor connected with electric press mould frame, the bottom end of the core rod is rigidly connected with the output end of core rod direct drive motor, the working section of the core rod is equipped with product inner hole forming structure, and the position of core rod is independent of upper punch and lower punch and is controlled separately;Through core rod direct drive motor independent control with inner hole forming structure's core rod movement, to make product inner hole structure direct integration in core rod forming surface, completely eliminate traditional punch end ≥0.15mm's forced step structure, avoid stress concentration and crack defect caused by step;Further realize no-step reverse demoulding product and the precision forming of bottom height difference remarkable product, break through the manufacturing limitation of traditional mould to complex inner hole structure.

Description

Technical Field

[0001] This utility model relates to the field of powder metallurgy forming mold technology, and more specifically, to a mold for electric core rod forming process. Background Technology

[0002] Traditional powder metallurgy pressing dies typically consist of an upper punch, a lower punch, a die sleeve, and a mandrel. The mandrel is often a fixed or cylinder-driven floating structure, and its forming position cannot be actively and precisely controlled; it can only remain fixed or passively move with the upper punch during extrusion. Because the mandrel's position is uncontrollable, the internal hole structure of the product cannot be directly designed onto the mandrel; it can only rely on the upper or lower punch to form the internal hole features. This design necessitates the addition of a stepped structure at the punch end to ensure die strength (typically with a step height ≥ 0.15 mm). This not only forces compromises in the product structure but also creates high-density areas at the steps, leading to stress concentration and crack defects.

[0003] Especially for complex structural products requiring reverse demolding and a stepless inner hole (such as reverse-angle holes and irregularly shaped internal cavities), traditional molds are completely incapable of achieving this due to the limitations of the mandrel's function. In existing technologies, the mandrel cannot be independently and precisely positioned, nor can it support the formed structure, severely restricting the manufacturing capability of high-precision, complex parts. The industry urgently needs a new mold solution that can actively control the mandrel's position and integrate the inner hole structure into the mandrel to solve the molding challenge of stepless inner hole products. Utility Model Content

[0004] In view of the above-mentioned technical problems in related technologies, this utility model proposes a mold for electric core rod forming process, which can overcome the above-mentioned shortcomings of the prior art.

[0005] To achieve the above-mentioned technical objectives, the technical solution of this utility model is implemented as follows:

[0006] A mold for electric core rod forming process;

[0007] The mold for the electric mandrel forming process includes an upper punch, a mold sleeve, a lower punch, and a mandrel. It also includes a mandrel direct drive motor connected to the mold frame of an electric press. The bottom end of the mandrel is rigidly connected to the output end of the mandrel direct drive motor. The working section of the mandrel is provided with a product inner hole forming structure, and the position of the mandrel is controlled independently of the upper punch and the lower punch.

[0008] Furthermore, the working section height H of the core rod satisfies the following relationship:

[0009]

[0010] Where H is the core rod forming depth; V is the alloy volume; and ρ is the alloy density.

[0011] C1 is the percentage of sintering weight loss; ρ_loose is the loose density of the raw material; S_upper is the projected area of ​​the upper punch; S_lower is the projected area of ​​the lower punch; h is the alloy height; K is the die shrinkage coefficient.

[0012] Furthermore, the working section height H of the core rod is in the range of 8mm ≤ H ≤ 35mm.

[0013] Furthermore, the bottom of the core rod is provided with a fixed round handle adapted to the electric press mold frame, and the axis of the fixed round handle is coaxial with the axis of the working section of the core rod.

[0014] Furthermore, it also includes a mold core, which has a positioning pin hole and a screw hole. The mold sleeve is detachably connected to the mold core through the screw hole, and the inner cavity contour of the mold sleeve matches the outer diameter shape of the product.

[0015] Furthermore, the core has dimensions of φ70mm×35mm, two locating pin holes, and six screw holes.

[0016] Furthermore, the bases of both the upper and lower punches are 3R standard interface structures, and the 3R standard interface is matched and connected to the drive unit of the electric press mold frame (7).

[0017] Furthermore, the inner wall of the mold sleeve is provided with a guide surface for guiding the downward punching motion, and the height of the guide surface is not less than 1.5 times the product height.

[0018] Furthermore, the positioning accuracy of the core rod direct drive motor is ≤ ±0.01mm, and its maximum output thrust is ≥20kN.

[0019] The beneficial effects of this utility model are as follows: By independently controlling the movement of the core rod with the inner hole forming structure through the core rod direct drive motor, the inner hole structure of the product is directly integrated into the core rod forming surface, completely eliminating the forced step structure of ≥0.15mm at the end of the traditional punch, avoiding stress concentration and crack defects caused by the step; thereby realizing the precision forming of stepless reverse demolding products and products with significant bottom height differences, breaking through the manufacturing limitations of traditional molds for complex inner hole structures. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the electric press mold frame according to an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the overall structure of a mold for electric core rod forming process according to an embodiment of the present utility model;

[0023] Figure 3 This is a schematic diagram of a conventional core rod structure according to an embodiment of the present utility model;

[0024] Figure 4 This is a schematic diagram of the core rod structure of a mold for electric core rod forming process according to an embodiment of the present utility model;

[0025] Figure 5 This is a schematic diagram of the underfill powder position structure of a mold for electric core rod forming process according to an embodiment of the present utility model.

[0026] Figure 6 This is a schematic diagram of the forming position structure of a mold for forming an electric core rod according to an embodiment of the present utility model.

[0027] Figure 7 This is a schematic diagram of the structure of the demolding inner hole that is co-oriented with the outer contour, produced according to the conventional core rod according to the embodiments of this utility model;

[0028] Figure 8 This is a schematic diagram of the structure of the conventional core rod production according to the embodiments of the present utility model, showing the inner hole (with steps) that is demolded in reverse to the outer contour.

[0029] Figure 9 This is a schematic diagram of the structure of the conventional core rod production (without steps) produced according to the embodiments of this utility model;

[0030] Figure 10 This is a schematic diagram of the structure of a crown drill bit produced by a mold used in an electric mandrel forming process according to an embodiment of the present utility model;

[0031] Figure 11 This is a schematic diagram of the structure of a gear cutter produced by a mold for electric core rod forming process according to an embodiment of the present utility model;

[0032] In the diagram: 1. Upper punch; 2. Mold sleeve; 3. Mold core; 4. Lower punch; 5. Core rod; 6. Core rod direct drive motor; 7. Electric press mold frame; 701. A-axis direct drive motor; 702. Press frame; 703. Upper punch template; 704. Material shoe drive motor; 705. Female mold template; 706. Base plate with fixed lower punch seat; 707. B-axis direct drive motor; 708. Press leveling shim; 8. Traditional core rod. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art are within the protection scope of the present utility model.

[0034] It should be understood that in the description of the embodiments of this utility model, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this utility model, "several" means two or more, unless otherwise explicitly specified.

[0035] like Figure 1 , Figure 2 , Figure 4 and Figure 5 , Figure 6 As shown, a mold for electric mandrel forming process according to an embodiment of the present invention includes an upper punch 1, a mold sleeve 2, a lower punch 4 and a mandrel 5, and also includes a mandrel direct drive motor 6 connected to an electric press mold frame 7. The bottom end of the mandrel 5 is rigidly connected to the output end of the mandrel direct drive motor 6. The working section of the mandrel 5 is provided with a product inner hole forming structure, and the position of the mandrel 5 is independently controlled by the upper punch 1 and the lower punch 4.

[0036] According to an embodiment of the present invention, a mold for forming an electric core rod is provided. In a specific embodiment, the working section height H of the core rod 5 satisfies the following relationship:

[0037]

[0038] Where H is the core rod forming depth; V is the alloy volume; and ρ is the alloy density.

[0039] C1 is the percentage of sintering weight loss; ρ_loose is the loose density of the raw material; S_upper is the projected area of ​​upper punch 1; S_lower is the projected area of ​​lower punch 4; h is the alloy height; K is the die shrinkage coefficient.

[0040] According to an embodiment of the present invention, a mold for forming an electric core rod is provided. In a specific embodiment, the working section height H of the core rod 5 is in the range of 8mm ≤ H ≤ 35mm.

[0041] According to an embodiment of the present invention, a mold for electric core rod forming process is provided at the bottom of the core rod 5, which is adapted to the electric press mold frame 7. The axis of the fixed round handle is coaxial with the axis of the working section of the core rod 5.

[0042] According to an embodiment of the present invention, a mold for forming an electric core rod is provided. In a specific embodiment, the mold core 3 is further provided with a positioning pin hole and a screw hole. The mold sleeve 2 is detachably connected to the mold core 3 through the screw hole, and the inner cavity contour of the mold sleeve 2 matches the outer diameter shape of the product.

[0043] According to an embodiment of the present invention, a mold for forming an electric core rod is provided. In a specific embodiment, the core 3 has a size of φ70mm×35mm, two positioning pin holes, and six screw holes.

[0044] According to an embodiment of the present invention, a mold for electric mandrel forming process is provided. In a specific embodiment, the bases of the upper punch 1 and the lower punch 4 are both 3R standard interface structures, and the 3R standard interface is matched and connected to the drive unit of the electric press mold frame 7.

[0045] According to an embodiment of the present invention, a mold for forming an electric core rod is provided. In a specific embodiment, the inner sidewall of the mold sleeve 2 is provided with a guide surface for guiding the movement of the lower punch 4. The height of the guide surface is not less than 1.5 times the height of the product.

[0046] According to an embodiment of the present invention, a mold for electric core rod forming process is provided. In a specific embodiment, the positioning accuracy of the core rod direct drive motor 6 is ≤ ±0.01mm, and its maximum output thrust is ≥20kN.

[0047] To facilitate understanding of the above-mentioned technical solutions of this utility model, the following detailed description of the above-mentioned technical solutions of this utility model is provided through specific usage methods.

[0048] In practical use, the mold for electric core rod forming process according to the present invention uses a high-precision electric press with a separate servo motor to control the core rod. The overall mold frame is as follows: This electric press can control the forming action and forming position of the core rod separately and precisely through the core rod direct drive motor, which provides the basis for the realization of the present invention.

[0049] 2. The design of the mold in this utility model is also different from the traditional molding process (this is the key innovation of this utility model): This utility model breaks through by designing the inner hole structure on the core rod. With the help of the precise control of the high-precision electric press, the entire molding process is completed. During the test, three design schemes were tested. After testing the abnormalities of the core rod design with different H values ​​in the actual manufacturing process, it was clarified that the H value needs to be within a fixed range to complete the pressing. Too large or too small an H value will cause serious cracks in the product.

[0050] In summary, the key to whether this utility model can be successfully formed lies in the design of the forming depth H. The size of H directly affects the degree of product deformation and the difficulty of crack repair. An unreasonable H value may directly lead to failure to form. Through theoretical calculation and time verification, a suitable design formula for the conventional H value is set. In other cases, the H value needs to be obtained by 3D software simulation calculation.

[0051] 3. The adjustment of the pressing process in this utility model is also different from the traditional molding process:

[0052] Traditional molding processes do not require a specific molding position because the core rod is straight up and down. Therefore, there is no need for machine adjustment during the adjustment process, and product abnormalities will not occur due to core rod adjustment issues.

[0053] Because the core rod of this invention has a specific structure, there are clear requirements for the forming position during molding. Furthermore, its varying shape can cause localized differences in pressing density, introducing new risks during machine adjustment. To mitigate these risks, the following points should be noted during machine adjustment for this invention:

[0054] 1) The process requires accurate calculation to determine the appropriate underfill powder value, ensuring that after the underfill powder action, the core rod and the lower punch are in the correct positions (their relative positions are close to the forming position).

[0055] 2): By adjusting the pressing speed of the machine, the core rod and the lower punch are kept in a state of near-relative stillness during movement, so as to reduce abnormalities such as cracks caused by friction between the two parting surfaces;

[0056] 3) For some products with complex structures, the local density difference can be balanced by adjusting the underfill position of the core rod and the pressure relief stroke of the N-axis (core rod axis) of the pressing speed, thereby further reducing the occurrence of abnormalities.

[0057] 4) This utility model divides the bottom of the product into two parts for pressing by designing a structure on the core rod. Therefore, the density of different parts can be controlled separately. In addition to solving the pressing problem of reverse back angle products, it can also effectively press products with large bottom height differences, such as crown drill bits.

[0058] The core technical point of the mold for electric core rod forming process described in this utility model is as follows:

[0059] 1. Fully utilize the characteristic that the electric mandrel can be controlled independently with high precision, and treat the mandrel as an independent punch to participate in the pressing process;

[0060] 2. The structural design of the core rod, through logical deduction and verification, yields the formula for calculating the H value under a 50% stroke ratio (optimal density distribution);

[0061] 3. Fully develop the independent control function of the N-axis (core rod axis) of the electric press, and complete the pressing of difficult-to-form products by using parameters such as pressing speed and pressure relief stroke in conjunction with mold design and process design.

[0062] The mold for electric mandrel forming process described in this utility model includes, in a specific embodiment, an upper punch 1, a mold sleeve 2, a mold core 3, a lower punch 4, and a mandrel 5. The upper punch 1 and the lower punch 4 are 3R bases adapted to the mold frame of an electric press. The mold core 3 has a size of φ70mm*35mm and is equipped with 2 positioning pin holes and 6 screw holes, adapted to the mold frame of an electric press. The mold sleeve 2 is designed according to product requirements and is adapted to and connected to the mold core 3 as a whole. The mandrel 5 is designed according to the product structure and the H calculation formula. Its bottom fixed round handle is also adapted to the electric press and is individually controlled by the mandrel direct drive motor 6 of the electric press.

[0063] During pressing, the die sleeve 2, lower punch 4, and core rod 5 return to their zero positions, while the upper punch 1 is raised to a height of 100mm for powder loading. After powder loading, the die sleeve 2 is raised separately by a certain distance to ensure no powder spraying due to insufficient powder loading. Simultaneously, through prior calculations, the relative positions of the lower punch 4 and core rod 5 are made close to their relative positions during molding. Subsequently, the upper punch 1 is pressed down, and the lower punch 4 and core rod 5 are raised relative to the die sleeve 2 while remaining relatively stationary, completing the pressing action with a 50% stroke ratio. Finally, by separately controlling the pressure release actions of the upper punch 1, lower punch 4, and core rod 5, the product is demolded without any abnormalities, and the entire pressing action is completed.

[0064] In summary, by utilizing the above-mentioned technical solution of this utility model, the movement of the core rod with the inner hole forming structure is independently controlled by the core rod direct drive motor, thereby allowing the inner hole structure of the product to be directly integrated into the core rod forming surface. This completely eliminates the forced step structure of ≥0.15mm at the end of the traditional punch, avoiding stress concentration and crack defects caused by the step. Furthermore, it enables the precision forming of stepless reverse demolding products and products with significant bottom height differences, breaking through the manufacturing limitations of traditional molds for complex inner hole structures.

[0065] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A mold for electric core rod forming process, characterized in that, It includes an upper punch (1), a die sleeve (2), a lower punch (4) and a core rod (5), and also includes a core rod direct drive motor (6) connected to the electric press die frame (7). The bottom end of the core rod (5) is rigidly connected to the output end of the core rod direct drive motor (6). The working section of the core rod (5) is provided with a product inner hole forming structure, and the position of the core rod (5) is independently controlled by the upper punch (1) and the lower punch (4).

2. The mold for electric core rod forming process according to claim 1, characterized in that, The working section height H of the core rod (5) satisfies the following relationship: Where H is the core rod forming depth; V is the alloy volume; and ρ is the alloy density. C1 is the percentage of sintering weight loss; ρ_loose is the loose density of the raw material; S_upper is the projected area of ​​the upper punch (1); S_lower is the projected area of ​​the lower punch (4); h is the alloy height; K is the mold shrinkage coefficient.

3. The mold for electric core rod forming process according to claim 1, characterized in that, The working section height H of the core rod (5) is in the range of 8mm≤H≤35mm.

4. The mold for electric core rod forming process according to claim 1, characterized in that, The bottom of the core rod (5) is provided with a fixed round handle adapted to the electric press mold frame (7), and the axis of the fixed round handle is coaxial with the axis of the working section of the core rod (5).

5. The mold for electric core rod forming process according to claim 1, characterized in that, It also includes a mold core (3), which has a positioning pin hole and a screw hole. The mold sleeve (2) is detachably connected to the mold core (3) through the screw hole, and the inner cavity contour of the mold sleeve (2) matches the outer diameter shape of the product.

6. A mold for electric core rod forming process according to claim 5, characterized in that, The core (3) has a size of φ70mm×35mm, two positioning pin holes, and six screw holes.

7. The mold for electric core rod forming process according to claim 1, characterized in that, The bases of the upper punch (1) and the lower punch (4) are both 3R standard interface structures, and the 3R standard interface is matched and connected to the drive unit of the electric press mold frame (7).

8. A mold for electric core rod forming process according to claim 1, characterized in that, The inner wall of the mold (2) is provided with a guide surface for guiding the movement of the punch (4), and the height of the guide surface is not less than 1.5 times the height of the product.

9. A mold for electric core rod forming process according to claim 1, characterized in that, The positioning accuracy of the core rod direct drive motor (6) is ≤ ±0.01mm, and its maximum output thrust is ≥20kN.

Images