Hardware injection molding part and preparation process thereof

Abstract

The invention relates to the technical field of hardware injection molding parts, and discloses a hardware injection molding part and a preparation technology thereof.The hardware injection molding part comprises the hardware injection molding part, the hardware injection molding part comprises a first right-angle piece, the right side of the first right-angle piece is bent and then connected with a first straight piece, the right side of the first straight piece is bent and then connected with an extrusion piece, and the right side of the extrusion piece is bent and then connected with a second straight piece; the right side of the second straight piece is bent to be connected with a second right-angle piece, the top of the first right-angle piece is bent to be connected with a double-exposed piece, and the top of the second right-angle piece is bent to be connected with a single-exposed piece. By adopting the scheme of transverse chain-shaped bending and vertical synchronous bending in a progressive die, all bending procedures are completed in a single die, and integral forming from a first right-angle sheet to a single exposed sheet is realized through strip positioning and station transfer, so that the situation that welding is needed when multiple dies are used for machining separately is eliminated, and the production efficiency is improved. In the prior art, hardware needs to be manufactured separately and depends on a machining mode of multiple sets of dies, and the problems that the die input cost is high, and working procedures are coordinated and complex are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal injection molded parts, and specifically to a metal injection molded part and a preparation process thereof. Background Art

[0002] A metal injection molded part is a composite component formed by integrally molding a metal insert and plastic, and is widely used in electronic connectors, automotive parts and precision instruments. Its core metal structure is usually composed of multiple bent sheet bodies, which are connected by welding or riveting processes, and finally embedded in an injection mold for plastic coating. Such components need to meet the requirements of structural strength, dimensional accuracy and production efficiency at the same time, especially at the interface parts where stress is frequently applied, high torsional stiffness is required.

[0003] At present, the existing metal injection molded parts, as key inserts for the structural connection of electronic devices, need to integrate multi-functional units such as right-angle sheets, extrusion sheets and anti-disengagement exposed sheets. Such components are subject to plugging and unplugging stress and injection shrinkage force for a long time. The traditional process disassembles them into split metal groups and combines them into an integral structure by welding, resulting in too many mold processes and complex procedures, and poor dimensional accuracy. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a metal injection molded part and a preparation process thereof, which solve the problems of too many mold processes, complex procedures and poor dimensional accuracy.

[0005] To achieve the above object, the present invention is realized through the following technical solutions: A metal injection molded part, including a metal injection molded part, the metal injection molded part includes a first right-angle sheet connected to a first straight sheet after being bent to the right, the first straight sheet is connected to an extrusion sheet after being bent to the right, the extrusion sheet is connected to a second straight sheet after being bent to the right, the second straight sheet is connected to a second right-angle sheet after being bent to the right, the top of the first right-angle sheet is bent to be connected to a double-exposed sheet, and the top of the second right-angle sheet is bent to be connected to a single-exposed sheet.

[0006] A preparation process for a metal injection molded part includes the following steps:

[0007] S1. Material preparation: Provide a metal strip as the raw material;

[0008] S2. Stamping and flattening: Perform a flattening treatment on the strip through a stamping die to compress the material thickness and increase the density;

[0009] S3. Continuous bending and forming: Sequentially complete the integral bending of the first right-angle sheet, the first straight sheet, the extrusion sheet, the second straight sheet, the second right-angle sheet, the double-exposed sheet and the single-exposed sheet in the same die;

[0010] S4. Cutting and separating: Cut from the strip to obtain a blank of the integrally formed metal injection molded part.

[0011] Preferably, the stamping and flattening in step S2 includes the following steps:

[0012] S201. Strip positioning: Convey the metal strip to the flattening station of the stamping die.

[0013] S202. Step-by-step compression: Press down twice by the upper die. For the first time, compress to 85%-90% of the original material thickness, and for the second time, compress to the target thickness with a compression rate of 10%-20%.

[0014] S203. Pressure holding and hardening: Keep the pressure for 0.5-1 second at the target thickness to form a cold work hardening layer on the surface of the material.

[0015] Preferably, in step S2, the compression rate of the flattening treatment is 10%-20% of the original material thickness, and a cold work hardening layer is formed after flattening.

[0016] Preferably, the continuous bending and forming in step S3 includes the following steps:

[0017] S301. Horizontal chain-like bending: Perform multiple bends in sequence at the same station to form a first right-angle piece, a first straight piece connected to its right side, an extrusion piece connected to the right side of the first straight piece, a second straight piece connected to the right side of the extrusion piece, and a second right-angle piece connected to the right side of the second straight piece in sequence, thus forming a horizontal chain-like structure.

[0018] S302. Vertical bending: Transfer to the next station and perform bending synchronously to form a double-exposed piece at the top of the first right-angle piece and a single-exposed piece at the top of the second right-angle piece.

[0019] Preferably, in step S301, an arc-shaped punch is used for bending the extrusion piece to form an arc-shaped extrusion surface protruding outward in the middle.

[0020] Preferably, the microhardness of the cold work hardening layer reaches HV200-250, and the thickness is 15%-25% of the total material thickness.

[0021] Preferably, in step S4, when cutting and separating, anti-disengagement chamfers are punched out synchronously at the ends of the double-exposed piece and the single-exposed piece.

[0022] Preferably, all bending processes are completed in the continuous stations of the progressive die, and the time from strip input to finished product output is ≤3 seconds per piece.

[0023] Preferably, in step S4, the cutting and separating includes the following steps:

[0024] S401. Precise positioning: Convey the bent strip to the cutting station of the progressive die, and achieve a positioning accuracy of ±0.02 mm by inserting a pilot pin into the positioning hole of the strip.

[0025] S402. Synchronous blanking: The upper die descends, and the cutting punch cuts along the end of the transverse chain structure, vertically cutting the strip on the right side of the second right-angle piece.

[0026] Synchronous triggering of the chamfering punch: At the moment of cutting, the lateral slider drives the chamfering punch to cut a 45°×0.3mm anti-disengagement chamfer at the ends of the double-exposed piece and the single-exposed piece.

[0027] S403. Ejection and separation from waste: The ejector pins of the lower die eject the finished hardware parts from the die cavity, and the cut waste slides into the waste collection box through the die slope.

[0028] The present invention provides a hardware injection molded part and its manufacturing process. It has the following beneficial effects:

[0029] 1. By adopting the scheme of transverse chain bending and vertical synchronous bending in the progressive die, all bending processes are completed in a single die. Through strip positioning and station transfer, the integral forming of the first right-angle piece to the single-exposed piece is achieved, thus eliminating the need for welding when processed by multiple dies separately. The prior art requires separate manufacturing of hardware parts and relies on the processing method of multiple sets of dies, solving the problems of high die investment cost and complex process coordination.

[0030] 2. The present invention adopts the stepped compression and flattening and cold work hardening layer generation technology. Through two compressions and pressure holding hardening, a hardening layer of HV200 - 250 is formed. By replacing the original welding process with this process, the material density is increased and the internal structure is strengthened. Compared with the prior art that relies on manual welding and subsequent inspection, the problems of low dimensional consistency caused by welding deformation and high additional inspection cost are solved.

[0031] 3. The present invention adopts the technology of precise positioning pilot pin and lateral slider linkage. At the cutting station, the part separation chamfering blanking is completed synchronously, and the anti-disengagement structure is integrally formed through a single stamping action, thus avoiding secondary processing. Compared with the prior art that needs to separately process the anti-disengagement structure, the problems of efficiency loss and positioning deviation caused by fragmented processes are solved.

[0032] 4. The present invention adopts the collaborative design of transverse chain bending and material hardening layer. In the bending of the extrusion piece, an arc punch is used to form a convex extrusion surface, combined with a cold work hardening layer with a thickness of 15% - 25% of the surface layer. Through this scheme, the anti-deformation ability of the bending area is improved, thus ensuring the morphological stability of the complex bending structure. Compared with the traditional welding combination process of separate hardware parts, the problems of insufficient strength at the connection part and deformation during long-term use are solved, and the overall structural reliability is improved. Description of the Drawings

[0033] Figure 1 It is a three-dimensional view of a hardware injection molded part of the present invention;

[0034] Figure 2Schematic side view of a hardware injection molded part of the present invention;

[0035] Figure 3 Process flow chart of a preparation process for a hardware injection molded part of the present invention;

[0036] Figure 4 Schematic diagram of the continuous bending and forming process of a preparation process for a hardware injection molded part of the present invention;

[0037] Figure 5 Schematic diagram of the cutting and separating process of a preparation process for a hardware injection molded part of the present invention.

[0038] Wherein, 1. Hardware injection molded part; 101. First right-angle piece; 102. First straight piece; 103. Extrusion piece; 104. Second straight piece; 105. Second right-angle piece; 106. Double-exposed piece; 107. Single-exposed piece. Detailed implementation manners

[0039] Next, in combination with the drawings of the present invention, the technical solutions of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] Please refer to the attached Figure 1 - attached Figure 2 , an embodiment of the present invention provides a hardware injection molded part, including the hardware injection molded part 1. The hardware injection molded part 1 includes that the right side of the first right-angle piece 101 is bent and then connected to the first straight piece 102, the right side of the first straight piece 102 is bent and then connected to the extrusion piece 103, the right side of the extrusion piece 103 is bent and then connected to the second straight piece 104, the right side of the second straight piece 104 is bent and then connected to the second right-angle piece 105, the top of the first right-angle piece 101 is bent and then connected to the double-exposed piece 106, and the top of the second right-angle piece 105 is bent and then connected to the single-exposed piece 107.

[0041] The sheet body is integrally stamped and bent from the same kind of metal strip (such as 304 stainless steel, phosphor bronze or spring steel);

[0042] "Connection" specifically refers to the physical continuity formed by the plastic deformation (bending) of the material itself, without additional connection points such as welding or riveting, and an R angle is formed at the bending root of adjacent sheet bodies.

[0043] The first right-angle piece 101 and the second right-angle piece 105 form the main installation or support base; the first straight piece 102 and the second straight piece 104 provide connection and transition; the extrusion piece 103 serves as an elastic or locking element; the double-exposed piece 106 and the single-exposed piece 107 are designed as insert parts for subsequent plastic injection molding and coating, and the "exposed" means that part of the surface is exposed outside the plastic to achieve specific functions (such as conduction, grounding, mechanical limiting).

[0044] Please refer to the attached Figure 3 - attached Figure 5 , a preparation process for a metal injection molded part, comprising the following steps:

[0045] S1. Material preparation: Provide a metal strip as the raw material;

[0046] S2. Stamping and flattening: Flatten the strip through a stamping die to compress the material thickness and increase the density;

[0047] S3. Continuous bending and forming: Sequentially complete the integral bending of the first right-angle piece 101, the first straight piece 102, the extrusion piece 103, the second straight piece 104, the second right-angle piece 105, the double-exposed piece 106, and the single-exposed piece 107 in the same die;

[0048] S4. Cutting and separating: Cut from the strip to obtain a blank of the integrally formed metal injection molded part.

[0049] Detailed refinement of S1 material preparation: The metal strip is continuously supplied in the form of a coil, and the width needs to match the unfolded width of the final part. The strip needs to be leveled before entering the die to eliminate the coiling stress and ensure flatness. The surface of the strip can be pre-coated with a stamping lubricant (such as light mineral oil or a polymer lubricating film) to reduce the friction coefficient and protect the die.

[0050] Deepening of the purpose of S2 stamping and flattening: The core purpose of the flattening process is to eliminate the thickness unevenness and micro-defects generated during the rolling or storage of the strip; through plastic deformation, the material grains are refined to improve the toughness and strength of the subsequent bending area; form a controllable cold work hardening layer to enhance the wear resistance and fatigue resistance of key stress-bearing parts (such as the bending root and the extrusion piece), replacing multiple small part preparations and welding processes in the traditional welding process.

[0051] Core of S3 continuous bending and forming: "The same die" specifically refers to a progressive die. All bending steps are continuously and automatically completed at different stations of the progressive die, and the workpiece is always conveyed attached to the strip, without manual intervention or transfer between processes, ensuring extremely high positional accuracy and efficiency. The bending sequence is optimized through precise simulation to avoid interference and control springback.

[0052] Significance of cutting and separation in S4: Cutting is the last working station of the progressive die. Precise cutting position and angle ensure that the part dimensions meet the design requirements. The "blank" obtained after cutting is the insert that can be directly used for subsequent injection molding without any secondary processing (such as deburring, shape correction) or welding and assembly.

[0053] The stamping and flattening in step S2 includes the following steps:

[0054] S201. Strip positioning: Convey the metal strip to the flattening station of the stamping die.

[0055] S202. Step-by-step compression: The upper die presses down twice. The first compression reduces the thickness of the raw material to 85%-90% of the original thickness, and the second compression reduces it to the target thickness with a compression rate of 10%-20%.

[0056] S203. Pressure holding and hardening: Keep the pressure for 0.5-1 second at the target thickness to form a cold work hardening layer on the surface of the material.

[0057] S201 positioning mechanism: Positioning is usually achieved by accurately inserting the pilot pins on the die into the pre-punched pilot holes on the strip, ensuring that the position repeat accuracy of the strip at the flattening station reaches within ±0.05 mm. The positioning accuracy is the basis for ensuring the consistency of the flattened area and the subsequent bending accuracy.

[0058] S202 step-by-step compression principle: Compressing in two steps (instead of one step) can effectively reduce the material flow resistance and internal shear stress, significantly reducing the risks of wrinkling and cracking, which is particularly crucial for materials with relatively thick or high hardening tendency (such as high carbon steel). The first compression provides preliminary plastic deformation and grain orientation adjustment for the material; the second compression achieves the final target thickness and a more uniform density distribution, balancing the empirical range of material property improvement (strength, hardness) and plastic loss (avoiding excessive hardening and embrittlement).

[0059] S203 pressure holding and hardening mechanism: Keeping the pressure (pressure holding) at the target thickness causes significant dislocation multiplication and entanglement in the material in a highly plastically deformed state, hindering grain boundary slip, thereby forming a cold work hardening layer on the surface. The pressure holding time of 0.5-1 s is a compromise value to ensure sufficient hardening effect without affecting the production rhythm. The pressure holding pressure is usually close to or equal to the pressure at the end of compression.

[0060] In step S2, the compression rate of the flattening treatment is 10%-20% of the raw material thickness, and a cold work hardening layer is formed after flattening.

[0061] Basis for compression ratio selection: 10% is the lowest effective threshold. Below this value, the hardening effect is not significant. 20% is the upper limit. Exceeding this value will cause a sharp drop in the plasticity of the material, making it prone to cracking during subsequent bending, and the required punching force will be too large. The specific value is selected according to the material type (for example, 10 - 15% for stainless steel and 15 - 20% for phosphor bronze) and the requirements of the part's functional area;

[0062] Characteristics of the cold work hardening layer: This hardening layer has a higher yield strength and microhardness than the core. Its thickness distribution is related to the deformation gradient, friction conditions, and holding time of the material during flattening. This hardening layer can effectively improve the ability of the part to withstand melt impact and holding pressure in the injection mold, as well as the wear resistance and anti-deformation ability of the final insert during use.

[0063] Step S3 of continuous bending forming includes the following steps:

[0064] S301. Transverse chain-like bending: Multiple bends are sequentially performed at the same station to form a first right-angle piece 101, a first straight piece 102 connected to its right side, an extrusion piece 103 connected to the right side of the first straight piece 102, a second straight piece 104 connected to the right side of the extrusion piece 103, and a second right-angle piece 105 connected to the right side of the second straight piece 104 in sequence, thus forming a transverse chain-like structure;

[0065] S302. Vertical bending: Transfer to the next station and perform bending synchronously. A double-exposed piece 106 is formed on the top of the first right-angle piece 101, and a single-exposed piece 107 is formed on the top of the second right-angle piece 105.

[0066] Implementation of S301 transverse chain-like bending: "The same station" refers to a specially designed multi-action bending station in the progressive die. This station usually includes multiple sliders, inclined wedges, or rotary cam mechanisms that act in sequence. Within one stroke of the punching press (or in cooperation with material lifting and stepping), the bending of the first right-angle piece 101, the first straight piece 102, the extrusion piece 103, the second straight piece 104, and the second right-angle piece 105 is completed in sequence. The bending angle is precisely controlled by the hard limit blocks on the die to avoid interference of the previously bent part with subsequent actions and control the cumulative springback;

[0067] Implementation of S302 vertical bending: "The next station" refers to one or more stations immediately following the transverse bending station in the progressive die. The bending of the double-exposed piece 106 and the single-exposed piece 107 is usually completed synchronously within the same stamping stroke and is performed by the independent bending punch of this station. The bending direction is perpendicular to the plane of the transverse chain structure, and the bending angle is also controlled by the die limit. Synchronous bending ensures the perpendicularity and positional accuracy of the double-exposed piece 106 and the single-exposed piece 107 relative to the first right-angle piece 101 and the second right-angle piece 105.

[0068] In step S301, the bending of the extrusion piece 103 uses an arc-shaped punch to form an outwardly convex arc-shaped extrusion surface in the middle.

[0069] Arc punch design: The working surface of the arc punch is a convex arc surface with a specific radius, which matches the flat bottom or matching concave arc surface of the die. The punch material is high wear-resistant tool steel or hard alloy;

[0070] Function of the extrusion surface: The formed outwardly convex arc extrusion surface 103 has the following core functions:

[0071] Elastic function: The arc-shaped structure provides a pre-compression space, which enables controllable elastic deformation during assembly to achieve interference fit or locking force;

[0072] Guiding function: The raised arc surface is conducive to guiding the insertion of the matching parts;

[0073] Increase contact: Compared with flat surfaces, curved surfaces can provide more uniform contact stress and higher load-bearing capacity when subjected to force. The selection of the arc radius needs to consider the required elastic deformation and material rebound characteristics.

[0074] The microhardness of the cold-work hardened layer reaches HV200-250, and the thickness is 15%-25% of the total thickness of the material.

[0075] Hardness test method: Microhardness HV200-250 is the average value measured by Vickers hardness tester on the cold-work hardened layer area of the part cross section (after inlaying, polishing, and corrosion). This hardness range ensures that the key areas of the parts have sufficient ability to resist plastic deformation and wear;

[0076] Hardened layer thickness measurement: The thickness of 15%-25% is determined by observing the cross-sectional microstructure under a metallographic microscope or by microhardness gradient testing.

[0077] In step S4 , when cutting and separating, anti-drop chamfers are punched out synchronously at the ends of the double exposed piece 106 and the single exposed piece 107 .

[0078] Anti-drop chamfering function: Chamfers are processed at the ends of the double exposed piece 106 and the single exposed piece 107. The core function of the chamfer is:

[0079] Eliminate burrs: The micro-burrs naturally present on the blanking edge are removed by chamfering to ensure safety and appearance;

[0080] Improve injection molding flow: sharp angles become blunt angles, which is conducive to the flow and wrapping of molten plastic on the edge of the insert and reduces filling defects;

[0081] Enhanced mechanical interlocking: The chamfered structure enables the plastic to "hook" the edge of the metal insert more firmly after cooling and shrinking, significantly improving the torsional load resistance and pull-off resistance between the plastic part and the insert.

[0082] All bending processes are completed in the continuous stations of the progressive die, and the time from strip input to finished product output is ≤ 3 seconds per piece.

[0083] In step S4, the cutting and separation includes the following steps:

[0084] S401, Precise positioning: Convey the bent strip to the cutting station of the progressive die, and achieve a positioning accuracy of ±0.02 mm by inserting the pilot pin into the positioning hole of the strip.

[0085] S402, Synchronous blanking: The upper die descends, and the cutting punch cuts the strip vertically at the end of the transverse chain structure on the right side of the second right-angle piece 105.

[0086] Synchronously trigger the chamfering punch: At the moment of cutting, the lateral slider drives the chamfering punch to punch a 45°×0.3 mm anti-loosening chamfer at the ends of the double-exposed piece 106 and the single-exposed piece 107.

[0087] S403, Ejecting and separating the waste: The ejector pin of the lower die ejects the finished hardware part out of the die cavity, and the cut waste slides into the waste collection box through the die ramp.

[0088] Guarantee for S401 precise positioning: The positioning accuracy of ±0.02 mm is the key to accurate cutting and chamfering dimensions.

[0089] High-precision pilot pin: Made of cemented carbide, precisely matched with the pre-punched pilot hole on the strip, and completes the final deviation correction before the die closes.

[0090] Rigid die set: High-precision ball guide pillars and bushings ensure the alignment accuracy of the upper and lower dies.

[0091] Realization of S402 synchronous blanking and chamfering: "Synchronous" means it is completed within one working stroke of the punching press. The cutting punch is responsible for separating the part from the strip, and its cutting edge shape needs to match the part contour. The chamfering punch is usually triggered by a lateral driving mechanism installed on the upper or lower die at an appropriate stage of the stroke to complete the chamfering processing of the ends of the double-exposed piece 106 and the single-exposed piece 107. 45°×0.3 mm is an empirical dimension that takes into account the deburring effect, interlocking strength, and influence on plastic flow.

[0092] Reliability of S403 ejecting and waste treatment: The ejecting mechanism consists of the punching rod of the punching press or the built-in spring of the die to ensure that the part is reliably separated from the lower die after the die opens. The ejecting force needs to be moderate to avoid part deformation. The die design needs to ensure a clear and non-interfering separation path for the finished product and the waste.

[0093] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hardware injection molded part, comprising a hardware injection molded part (1), characterized in that: The hardware injection molded part (1) includes a first right-angle piece (101) with a first straight piece (102) connected after bending to the right side, a pressing piece (103) connected after bending to the right side of the first straight piece (102), a second straight piece (104) connected after bending to the right side of the pressing piece (103), a second right-angle piece (105) connected after bending to the right side of the second straight piece (104), a double-exposed piece (106) connected after bending to the top of the first right-angle piece (101), and a single-exposed piece (107) connected after bending to the top of the second right-angle piece (105).

2. A preparation process for a metal injection molded part, characterized in that, For a hardware injection molded part as described in claim 1, it includes the following steps: S1. Stock preparation: Provide a metal strip as the raw material. S2. Stamping and flattening: Flatten the strip through a stamping die to compress the material thickness and increase the density. S3. Continuous bending and forming: Sequentially complete the integral bending of the first right-angle piece (101), the first straight piece (102), the pressing piece (103), the second straight piece (104), the second right-angle piece (105), the double-exposed piece (106), and the single-exposed piece (107) in the same die. S4. Cutting and separating: Cut from the strip to obtain a blank of the integrally formed hardware injection molded part.

3. A preparation process for a hardware injection molding part according to claim 2, characterized in that: The step S2 of stamping and flattening includes the following steps: S201. Strip positioning: Transport the metal strip to the flattening station of the stamping die. S202. Step-by-step compression: Press down twice by the upper die. For the first time, compress to 85%-90% of the original material thickness, and for the second time, compress to the target thickness with a compression rate of 10%-20%. S203. Pressure holding and hardening: Hold the pressure for 0.5 - 1 second at the target thickness to form a cold work hardening layer on the material surface.

4. A preparation process for a hardware injection molding part according to claim 2, characterized in that: In the step S2, the compression rate of the flattening treatment is 10%-20% of the original material thickness, and a cold work hardening layer is formed after flattening.

5. A preparation process for a hardware injection molding part according to claim 2, characterized in that: The step S3 of continuous bending and forming includes the following steps: S301. Horizontal chain-like bending: Perform multiple bends sequentially at the same station, and sequentially form the first right-angle piece (101), the first straight piece (102) connected to its right side, the pressing piece (103) connected to the right side of the first straight piece (102), the second straight piece (104) connected to the right side of the pressing piece (103), and the second right-angle piece (105) connected to the right side of the second straight piece (104) to form a horizontal chain-like structure. S302. Vertical bending: Transfer to the next station and perform bending synchronously to form a double-exposed piece (106) at the top of the first right-angle piece (101) and a single-exposed piece (107) at the top of the second right-angle piece (105).

6. The preparation process of a hardware injection molding part according to claim 4, characterized in that: In the step S301, the bending of the pressing piece (103) uses an arc-shaped punch to form an outwardly convex arc-shaped pressing surface in the middle.

7. A preparation process for a hardware injection molding part according to claim 3, characterized in that: The microhardness of the cold work hardening layer reaches HV200 - 250, and the thickness is 15%-25% of the total material thickness.

8. A preparation process for a hardware injection molded part according to claim 2, characterized in that: In the step S4, when cutting and separating, anti-loosening chamfers are synchronously punched at the ends of the double-exposed piece (106) and the single-exposed piece (107).

9. The preparation process of a hardware injection molded part according to claim 2, characterized in that: All bending processes are completed in the continuous stations of the progressive die, and the time from strip input to finished product output is ≤ 3 seconds per piece.

10. A preparation process for a hardware injection molding part according to claim 2, characterized in that: The step S4 of cutting and separating includes the following steps: S401. Precise positioning: Convey the bent strip to the cutting station of the progressive die, and achieve a positioning accuracy of ±0.02 mm by inserting the pilot pin into the positioning hole of the strip. S402. Synchronous blanking: The upper die descends, and the cutting punch cuts the strip vertically at the end of the transverse chain structure and on the right side of the second right-angle piece (105). Synchronously trigger the chamfering punch: At the moment of cutting, the lateral slider drives the chamfering punch to punch a 45°×0.3 mm anti-disengagement chamfer at the ends of the double-exposed piece (106) and the single-exposed piece (107). S403. Ejection and separation from waste: The ejector pin of the lower die ejects the finished hardware part from the die cavity, and the cut waste slides into the waste collection box through the die slope.

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