Injection molding device and injection molding process for metal powder metallurgy production

Abstract

The application relates to the technical field of metal product injection molding equipment, in particular to an injection molding device for metal powder metallurgy production and an injection molding process. The technical scheme comprises a base, a motor and an electromagnetic pulse generator are fixedly connected to the top of the base, a multi-energy cascade shaft device is transmissionally connected to the driving end of the motor, one end of the multi-energy cascade shaft device, which is far away from the motor, is transmissionally connected with the electromagnetic pulse generator, and a feeding screw rod is transmissionally connected to the output end of the electromagnetic pulse generator; a feeding seat is fixed to the top side of the base, a feeding inner sleeve is fixedly connected to the inner side of the feeding seat, and one end of the feeding screw rod, which is far away from the motor, extends and penetrates into the inside of an extrusion sleeve; and a screw rod piston head is fixedly connected to the tail end of the feeding screw rod. The application can cut off negative pressure, prevent backflow and strengthen material kneading through pulse screw linkage hydraulic sliding blocks, can stabilize pressure and increase pressure through double Venturi effects, can effectively eliminate pressure fluctuation, and can ensure uniform mixing and smooth injection of metal powder.

Description

Technical Field

[0001] This invention relates to the field of metal product injection molding equipment technology, and in particular to an injection molding device and injection molding process for metal powder metallurgy production. Background Technology

[0002] Metal powder injection molding (MIM) is a novel near-net-shape molding technology that combines plastic injection molding with physical metallurgy. This technology typically involves mixing metal powder with a specific binder to create a feedstock, which is then precisely injected into a mold cavity using an injection molding device. As the core hardware of the MIM process, the plasticizing, conveying, and injection performance of the injection molding device directly determines the internal density, dimensional accuracy, and structural uniformity of the final metal parts. In recent years, with the surge in demand for complex-shaped, high-strength metal parts in precision manufacturing fields such as aerospace, medical devices, and 3C electronics, extremely high standards have been set for metal powder injection molding devices in terms of feed stability, material mixing uniformity, and high-precision injection pressure control.

[0003] Current conventional metal powder metallurgy injection molding equipment typically consists of basic components such as a hopper, heating sleeve, internal conveying screw, drive motor, and mold. Its basic working principle is as follows: Material is fed into the barrel from the hopper, where it melts and plasticizes under the combined action of heat conduction from the external heating sleeve and mechanical shear friction generated by the rotation of the internal screw. Subsequently, the drive motor drives the screw to rotate unidirectionally and propel it forward, continuously conveying the molten metal to the storage area at the front of the barrel. Finally, the material is forced under high pressure into the cavity composed of the moving mold and the fixed mold through the unidirectional linear translation and pushing of the screw. This type of traditional equipment relies on the continuous rotation and unidirectional direct push of the screw to complete injection molding, and can meet the mass production requirements of conventional metal components with general precision requirements.

[0004] However, existing traditional injection molding equipment faces significant technical bottlenecks when handling flexible injection molding of metal powders with high density requirements. Firstly, existing equipment lacks an adaptive pressure stabilization structure at the injection end, making it prone to pressure fluctuations during material transport and extrusion, resulting in uneven final output and unstable flow rate. This unresolved technical problem severely limits the yield and mechanical properties of high-end metal powder injection molded parts. Therefore, this application proposes an injection molding device and injection molding process for metal powder metallurgy production. Summary of the Invention

[0005] The purpose of this invention is to address the problem that existing injection molding devices lack an adaptive pressure stabilizing structure at the injection end, which easily leads to pressure fluctuations during material conveying and extrusion, resulting in uneven material output and unstable flow rate. This invention proposes an injection molding device and injection molding process for metal powder metallurgy production.

[0006] In a first aspect, this application provides an injection molding device for metal powder metallurgy production, comprising a base, a motor and an electromagnetic pulse generator fixedly connected to the top of the base, a multi-stage coupling drivingly connected to the drive end of the motor, the end of the multi-stage coupling away from the motor being drivingly connected to the electromagnetic pulse generator, and a feeding screw drivingly connected to the output end of the electromagnetic pulse generator; a feed seat fixedly connected to the top side of the base, an inner feed sleeve fixedly connected to the inner side of the feed seat, the end of the feeding screw away from the motor extending and penetrating into the interior of the extrusion sleeve; a screw piston head fixedly connected to the end of the feeding screw, a piston sleeve slidably fitted to the outer side of the screw piston head, a variable cross-section control flange fixedly connected to the middle of the end of the piston sleeve away from the feeding screw, a pressure-reducing chamber and a driving pressure chamber being opened inside the variable cross-section control flange, a sliding control slider being slidably connected to the inner side of the driving pressure chamber, and a stable section barrel with a stable storage chamber fixedly connected to the rear end of the variable cross-section control flange.

[0007] Optionally, a feed pipe base is fixedly connected to the top side of the inner feed sleeve, and a hopper is fixedly connected to the top side of the feed pipe base. A fixed flange is fixedly connected to the end of the inner feed sleeve away from the motor. The inner side of the fixed flange is fixedly connected to the outer side of the extrusion sleeve. A sealing retaining ring and a screw piston head are coaxially fixedly connected to the end of the feeding screw away from the motor. A high-temperature resistant silicone oil inner cavity is opened inside the piston sleeve, and the screw piston head is movably connected to the inner side of the high-temperature resistant silicone oil inner cavity.

[0008] Optionally, heating jackets are installed on the outer sides of both the extrusion sleeve and the stabilizing section barrel. A support base is fixedly connected to the bottom side of the heating jacket, and the bottom side of the support base is fixedly connected to the top of the base. A protective cover is provided on the outer side of the heating jacket, and the bottom side of the protective cover is fixedly connected to the top side of the base. The front end of the protective cover is fixedly connected to the outside of the fixed flange.

[0009] Optionally, transition connecting blocks are fixedly connected to both the top and bottom sides of the variable cross-section control flange. The end of the transition connecting block away from the variable cross-section control flange is fixedly connected to the outside of the piston sleeve. An inert fluid flow channel communicating with the high-temperature silicone oil inner cavity is opened inside the piston sleeve and the transition connecting block. The high-temperature silicone oil inner cavity is connected to the driving pressure chamber through the inert fluid flow channel.

[0010] Optionally, the end of the inert fluid channel away from the high-temperature silicone oil cavity passes through the pressure-relieving chamber, and the pressure-relieving chamber is connected to the driving pressure chamber.

[0011] Optionally, a flow box is fixed to the outside of the piston sleeve, and a plurality of feeding flow channels are provided on the inside of the flow box; a feeding inlet communicating with the feeding flow channels is opened on the side wall of the extrusion sleeve, and a feeding outlet communicating with the end of the feeding flow channel away from the feeding inlet is provided on the inner wall of the variable cross-section control flange.

[0012] Optionally, the variable cross-section control flange also has a throat storage cavity inside, the feeding outlet is connected to the throat storage cavity, and one end of the sliding control slider extends into the throat storage cavity.

[0013] Optionally, a stabilizing section barrel is fixedly connected to the side of the variable cross-section control flange away from the extrusion sleeve. The stabilizing section barrel has a stabilizing storage chamber and a throat discharge chamber inside. A connecting flange is fixedly connected to the end of the stabilizing section barrel away from the variable cross-section control flange. A fixed mold is fixedly connected to the outside of the connecting flange. A moving mold abuts against the outside of the fixed mold. The moving mold is slidably connected to the top side of the base.

[0014] Secondly, this application provides an injection molding process for metal powder metallurgy production, applied to the injection molding apparatus for metal powder metallurgy production described in the first aspect, the injection molding process comprising the following steps:

[0015] Feeding and preheating: Metal powder enters the inner feeding sleeve from the hopper and finally enters the feeding screw. The material in the extrusion sleeve is melted by the heating sleeve.

[0016] Hydraulic kinetic energy is transmitted synchronously, and the electromagnetic pulse generator drives the feeding screw to pulsate axially. The screw piston head at the end synchronously compresses the medium in the high-temperature silicone oil cavity, and transmits the pulse pressure to the drive pressure chamber with zero delay through the inert fluid flow channel.

[0017] The linkage valve anti-suction control is as follows: when the feeding screw pulses forward, the hydraulic system pushes the sliding control slider to extend axially, actively adjusting the Venturi cross section of the throat storage chamber to accelerate material conveying; when the feeding screw pulses backward to reset, the sliding control slider synchronously closes or reduces the channel, cutting off and offsetting the instantaneous negative pressure generated by the screw retraction, locking the material in the rear stable storage chamber to prevent it from being sucked back.

[0018] The shearing flow channel reciprocates and pressurizes. During the reciprocating pulsation of the feeding screw, the suction and extrusion actions of the screw piston head simultaneously apply reverse reciprocating pressure to the metal powder material in multiple feeding flow channels, so that the material is fully kneaded and mixed under shearing force.

[0019] Stable injection molding eliminates pulsating negative pressure, and the material flow rate in the stable storage chamber tends to be stable. Then, it undergoes passive conical pressurization through the secondary Venturi effect of the end throat discharge chamber, and finally is injected into the cavity formed by the fixed mold and the moving mold through the throat discharge chamber for molding.

[0020] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0021] 1. This application uses the reciprocating pulsating structure of the feeding screw and the screw piston head to drive the medium in the high-temperature silicone oil cavity to push the sliding control slider structure to work, thereby solving the problem of preventing material backflow by cutting off the instantaneous negative pressure of the synchronous closed channel, and achieving the effect of reciprocating pressure and shearing kneading mixing of metal powder in the channel.

[0022] 2. Furthermore, with the cooperation of the throat storage chamber in the variable cross-section control flange and the end throat discharge chamber in the stable section barrel, the injection molding material generates a double Venturi effect during the conveying and extrusion process to stabilize the pressure and increase the conical pressure. This solves the problem of uneven material discharge caused by pressure fluctuations during the feeding process, thereby effectively eliminating pulsating negative pressure and maintaining stable injection in the stable section. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the three-dimensional structure;

[0024] Figure 2 This is a structural diagram of the protective outer casing;

[0025] Figure 3 This is a schematic diagram of the feeding screw.

[0026] Figure 4 This is a schematic diagram of the extrusion sleeve structure;

[0027] Figure 5 This is a schematic diagram of the screw piston head.

[0028] Figure 6 This is a schematic diagram of an inert fluid flow channel.

[0029] Figure 7 This is a schematic diagram of the feeding flow channel.

[0030] Figure 8 This is a schematic diagram of the sliding control slider.

[0031] Figure 9 This is a schematic diagram of the structure of a stable material storage chamber.

[0032] Reference numerals: 1. Base; 2. Hopper; 3. Motor; 4. Multi-stage coupling; 5. Electromagnetic pulse generator; 6. Moving mold; 7. Protective cover; 8. Heating jacket; 9. Flow box; 10. Feed seat; 11. Feed pipe base; 12. Inner feed sleeve; 13. Feed screw; 14. Sealing ring; 15. Fixed flange; 16. Extrusion sleeve; 17. Stable section barrel; 18. Screw piston head; 19. Durable 20. High-temperature silicone oil inner cavity; 21. Inert fluid flow channel; 22. Pressure relief cavity; 23. Drive pressure cavity; 24. Sliding control slider; 25. Feed outlet; 26. Piston sleeve; 27. Transition connecting block; 28. Variable cross-section control flange; 29. ​​Feed flow channel; 30. Feed inlet; 31. Throat storage cavity; 32. Support seat; 33. Fixed mold; 34. Connecting flange; 35. Stable storage cavity; 36. Throat discharge cavity. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0034] like Figures 1-3 As shown, the present invention proposes an injection molding device for metal powder metallurgy production, comprising a base 1, on the top of which a motor 3 and an electromagnetic pulse generator 5 are fixedly connected. The base 1 provides a stable physical support foundation for the entire machine, while the combination of the motor 3 and the electromagnetic pulse generator 5 is designed to provide a dual power source of rotational drive and high-frequency impact for subsequent material conveying.

[0035] The drive end of the motor 3 is connected to a multi-stage coupling 4. The end of the multi-stage coupling 4 furthest from the motor 3 is connected to an electromagnetic pulse generator 5. The output end of the electromagnetic pulse generator 5 is connected to a feeding screw 13. Through the flexible connection of the multi-stage coupling 4, the system can effectively couple rotational torque with pulse oscillation, enabling the feeding screw 13 to perform axial "forward, backward, forward" pulse oscillation at an extremely high frequency while rotating and propelling the material.

[0036] like Figure 3 As shown, a feed pipe base 11 is fixedly connected to the top side of the inner feed sleeve 12, and a hopper 2 is fixedly connected to the top side of the feed pipe base 11. The hopper 2 serves as the initial storage unit for materials and is vertically connected to the inner feed sleeve 12 below through the feed pipe base 11. It utilizes the combined effects of gravity and suction to improve the efficiency of powder entering the feed screw 13.

[0037] The inner feed sleeve 12, away from the motor 3, is fixedly connected to a fixed flange 15, which is fixedly connected to the outer side of the extrusion sleeve 16. The mechanical fastening of the fixed flange 15 ensures a rigid connection between the feeding system and the extrusion sleeve 16, preventing loosening or material leakage at the connection point when subjected to high-frequency pulse loads.

[0038] like Figures 2-4 As shown, heating jackets 8 are installed on the outside of both the extrusion sleeve 16 and the stabilizing section barrel 17. The heating jackets 8 rapidly heat the solid metal powder inside the extrusion sleeve 16 to a molten or semi-solid state through electrothermal radiation or induction heating, providing the necessary flowability for subsequent precision injection molding in the stabilizing section barrel 17.

[0039] A support base 31 is fixedly connected to the bottom side of the heating jacket 8, and the bottom side of the support base 31 is fixedly connected to the top of the base 1. The support base 31 not only serves to physically support the heating jacket 8, but its structural design also takes into account the thermal insulation effect, preventing high-temperature heat from being directly conducted downwards to the base 1 and thus damaging precision components such as the motor 3 at the bottom.

[0040] The heating jacket 8 is equipped with a protective cover 7 on its outer side. The bottom side of the protective cover 7 is fixedly connected to the top side of the base 1, and the front end of the protective cover 7 is fixedly connected to the outside of the fixed flange 15. The protective cover 7 forms a safety barrier on the outside, which can not only prevent the operator from being burned by the heating jacket 8, but also reduce heat loss by using a full-coverage structure, and the connection with the fixed flange 15 enhances the overall stability of the cover.

[0041] like Figures 3-5 As shown, a feed seat 10 is fixed to the top side of the base 1, and a feed inner sleeve 12 is fixedly connected to the inner side of the feed seat 10. The end of the feeding screw 13 away from the motor 3 extends and penetrates into the interior of the extrusion sleeve 16. The feed seat 10 serves to receive external raw materials and, together with the feed inner sleeve 12, guides the metal powder into the extrusion sleeve 16, ensuring that the feeding screw 13 can maintain the continuity and sealing of the feeding process even under high-speed operation.

[0042] In this embodiment, a sealing ring 14 and a screw piston head 18 are coaxially fixedly connected to the end of the feeding screw 13 away from the motor 3. The sealing ring 14 forms a dynamic sealing barrier on the feeding screw 13, effectively isolating the metal powder in the conveying area from the hydraulic medium in the transmission area, and preventing the screw piston head 18 from being worn and corroded by powder particles.

[0043] The feeding screw 13 has a screw piston head 18 fixedly connected to its end. A piston sleeve 25 is slidably fitted on the outside of the screw piston head 18. A variable cross-section control flange 27 is fixedly connected to the middle of the end of the piston sleeve 25 away from the feeding screw 13. The screw piston head 18, located at the end of the feeding screw 13, acts like a reciprocating power pump core. It performs micro-amplitude high-frequency pulsations within the piston sleeve 25, converting mechanical vibration energy into hydraulic energy and transmitting it to the variable cross-section control flange 27.

[0044] The piston sleeve 25 has a high-temperature resistant silicone oil cavity 19 inside, and the screw piston head 18 is movably connected to the inside of the high-temperature resistant silicone oil cavity 19. The special silicone oil filled in the high-temperature resistant silicone oil cavity 19 serves as a pressure transmission medium, which can withstand the high-temperature environment during the injection molding process, and works with the screw piston head 18 to pump electromagnetic pulse energy to the front end with zero delay.

[0045] like Figures 5-7 As shown, the variable cross-section control flange 27 has a pressure-reducing chamber 21 and a driving pressure chamber 22 inside. A sliding control slider 23 is slidably connected inside the driving pressure chamber 22. The pressure-reducing chamber 21 serves as overpressure protection and fluid buffer, while the sliding control slider 23 in the driving pressure chamber 22 directly responds to the hydraulic signal and achieves precise adjustment of the flow channel cross-sectional area through its reciprocating movement.

[0046] In this embodiment, a stable section barrel 17 with a stable material storage cavity 34 is fixedly connected to the rear end of the variable cross-section control flange 27. The stable section barrel 17 uses the stable material storage cavity 34 inside to physically homogenize the pressure fluctuations caused by the high-frequency pulsation at the front end, thereby ensuring that the material flow field injected into the mold is in a constant pressure state.

[0047] The variable cross-section control flange 27 is fixedly connected to both its top and bottom sides by transition connecting blocks 26. The end of the transition connecting block 26 away from the variable cross-section control flange 27 is fixedly connected to the outside of the piston sleeve 25. As a mechanical fulcrum and a carrier for the fluid channel, the transition connecting block 26 strengthens the assembly strength between the variable cross-section control flange 27 and the piston sleeve 25, ensuring the structural stability of the internal pressure transmission path.

[0048] like Figure 6 , Figure 7 As shown, the piston sleeve 25 and the transition connecting block 26 have an inert fluid channel 20 that communicates with the high-temperature silicone oil inner cavity 19. The high-temperature silicone oil inner cavity 19 and the driving pressure chamber 22 are connected through the inert fluid channel 20. This connection structure allows pressure fluctuations in the high-temperature silicone oil inner cavity 19 to be quickly guided to the driving pressure chamber 22 along the inert fluid channel 20, thereby driving the front-end component to produce precise displacement.

[0049] In this embodiment, the end of the inert fluid channel 20 that is away from the high-temperature silicone oil cavity 19 passes through the pressure-reducing cavity 21, and the pressure-reducing cavity 21 is connected to the driving pressure cavity 22. By allowing the inert fluid channel 20 to pass through the pressure-reducing cavity 21 before entering the driving pressure cavity 22, unstable peak pressures in the pulse can be filtered out, making the movement of the sliding control slider 23 smoother and more controllable.

[0050] A flow box 9 is fixed to the outside of the piston sleeve 25, and multiple feeding channels 28 are provided inside the flow box 9. The feeding channels 28 inside the flow box 9 increase the flow path distribution of the material during the extrusion process, so that the material is subjected to more shear force when passing through.

[0051] The extrusion sleeve 16 has a feeding inlet 29 on its side wall, which communicates with the feeding passage 28. The variable cross-section control flange 27 has a feeding outlet 24 on its inner side wall, which communicates with the end of the feeding passage 28 away from the feeding inlet 29. After entering through the feeding inlet 29, the material is distributed through the passage and finally converges at the feeding outlet 24. With the reciprocating pulse of the feeding screw 13, the material generates a reciprocating pressure effect in the feeding passage 28, thereby achieving the technical purpose of thorough kneading and mixing.

[0052] like Figure 7 and Figure 8 As shown, the variable cross-section control flange 27 also has a throat storage cavity 30 inside, and the feed outlet 24 is connected to the throat storage cavity 30. One end of the sliding control slider 23 extends into the throat storage cavity 30. This structure allows the sliding control slider 23 to directly intervene in the effective passage of the throat storage cavity 30. Utilizing the Venturi principle, it actively opens when the feed screw 13 advances forward, accelerating the material transfer downstream.

[0053] The variable cross-section control flange 27 is fixedly connected to the side away from the extrusion sleeve 16 with a smoothing section barrel 17. The smoothing section barrel 17 serves as the last rectification zone before material injection molding, and its length and structural design are intended to completely eliminate residual fluctuations left by the high-frequency pulses of the feed screw 13.

[0054] In this embodiment, the barrel 17 of the stabilizing section is provided with a stabilizing storage chamber 34 and a throat discharge chamber 35. When the constant-pressure material accumulated in the stabilizing storage chamber 34 passes through the throat discharge chamber 35, a secondary Venturi effect is generated, resulting in passive pressurization. Since the sliding control slider 23 automatically rebounds and closes according to the material pressure when the screw retracts, it effectively prevents the material in the stabilizing storage chamber 34 from being sucked back due to negative pressure.

[0055] like Figure 8-9As shown, a connecting flange 33 is fixedly connected to the end of the stable section barrel 17 away from the variable cross-section control flange 27, and a fixed mold 32 is fixedly connected to the outside of the connecting flange 33. The connecting flange 33 ensures the coaxiality between the stable section barrel 17 and the fixed mold 32, so that the high-density molten metal can be accurately aligned with the feed port of the fixed mold 32.

[0056] In this embodiment, a movable mold 6 abuts against the outer side of the fixed mold 32, and the movable mold 6 is slidably connected to the top side of the base 1. The movable mold 6 slides back and forth on the base 1 to realize the opening and closing of the mold. After closing with the fixed mold 32, it forms the final part cavity. With the stable pressure flow at the front end, it realizes the molding of high-quality, bubble-free metal powder metallurgy parts.

[0057] like Figures 1-9 As shown, an injection molding process for metal powder metallurgy production includes the following steps:

[0058] Feeding and preheating: Metal powder enters from hopper 2 into the inner feed sleeve 12 and finally into the feed screw 13. The material inside the extrusion sleeve 16 is melted by the heating sleeve 8. This step, through precise temperature control, softens the binder between metal particles, laying the flow foundation for subsequent high-frequency pulse conveying.

[0059] Synchronous transmission of hydraulic kinetic energy: The electromagnetic pulse generator 5 drives the feeding screw 13 to pulsate axially, and the screw piston head 18 at its end synchronously compresses the medium in the high-temperature resistant silicone oil inner cavity 19, transmitting the pulse pressure to the drive pressure chamber 22 through the inert fluid flow channel 20. This process achieves precise conversion of mechanical energy into hydraulic pulse energy, and by utilizing the incompressible property of liquid, it ensures complete synchronization between the oscillation at the rear end and the action of the front-end control element;

[0060] Linkage valve anti-suction control: When the feeding screw 13 advances forward with pulses, the hydraulic system pushes the sliding control slider 23 to extend axially, actively adjusting the Venturi cross section of the throat storage chamber 30 to accelerate material conveying. This dynamic adjustment process significantly improves the instantaneous flow rate. When the screw retracts and resets, the sliding control slider 23 will automatically return to its original position to close the channel using the linkage mechanism or pressure difference, locking the material in the stable storage chamber 34 to prevent it from being sucked back, thus eliminating the negative pressure interference caused by the return suction.

[0061] Reciprocating pressure in shear channels: During the reciprocating pulsation of the feeding screw 13, the suction and extrusion actions of the screw piston head 18 simultaneously apply reverse reciprocating pressure to the metal powder material in multiple feeding channels 28. This high-frequency reciprocating shear stress forces the material to mix violently in the micro-channels, greatly improving the dispersion uniformity of the metal powder and avoiding component segregation in the finished product;

[0062] Stable injection molding with stabilized pressure: After eliminating pulsating negative pressure, the material flow rate tends to stabilize in the stable storage chamber 34. Then, passive conical pressurization is achieved through the secondary Venturi effect of the end throat discharge chamber 35, and finally, it is injected into the cavity formed by the fixed mold 32 and the moving mold 6 for molding. This strategy of first stabilizing the pressure and then applying secondary passive pressure ensures that the molten metal has extremely high density and surface precision at the moment of mold filling.

[0063] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. An injection molding device for metal powder metallurgy production, characterized in that, The base (1) includes a base (1), on which a motor (3) and an electromagnetic pulse generator (5) are fixedly connected. The drive end of the motor (3) is driven by a multi-stage coupling (4), and the end of the multi-stage coupling (4) away from the motor (3) is driven by the electromagnetic pulse generator (5). The output end of the electromagnetic pulse generator (5) is driven by a feeding screw (13). A feed seat (10) is fixed on the top side of the base (1), and an inner feed sleeve (12) is fixedly connected to the inner side of the feed seat (10). The end of the feeding screw (13) away from the motor (3) extends and penetrates into the extrusion sleeve (12). Inside 6); a screw piston head (18) is fixedly connected to the end of the feeding screw (13), a piston sleeve (25) is slidably fitted on the outside of the screw piston head (18), a variable cross-section control flange (27) is fixedly connected to the middle of the end of the piston sleeve (25) away from the feeding screw (13), a pressure relief chamber (21) and a driving pressure chamber (22) are opened inside the variable cross-section control flange (27), a sliding control slider (23) is slidably connected to the inside of the driving pressure chamber (22), and a stable section barrel (17) with a stable storage chamber (34) is fixedly connected to the rear end of the variable cross-section control flange (27).

2. The injection molding device for metal powder metallurgy production according to claim 1, characterized in that, The top side of the inner feed sleeve (12) is fixedly connected to the feed pipe base (11), and the top side of the feed pipe base (11) is fixedly connected to the hopper (2). The end of the inner feed sleeve (12) away from the motor (3) is fixedly connected to the fixed flange (15). The inner side of the fixed flange (15) is fixedly connected to the outer side of the extrusion sleeve (16). The end of the feeding screw (13) away from the motor (3) is coaxially fixedly connected to the sealing retaining ring (14) and the screw piston head (18). The piston sleeve (25) has a high temperature resistant silicone oil inner cavity (19) inside, and the screw piston head (18) is movably connected to the inner side of the high temperature resistant silicone oil inner cavity (19).

3. The injection molding device for metal powder metallurgy production according to claim 1, characterized in that, Heating sleeves (8) are installed on the outside of the extrusion sleeve (16) and the stable section barrel (17). A support base (31) is fixedly connected to the bottom side of the heating sleeve (8). The bottom side of the support base (31) is fixedly connected to the top of the base (1). A protective cover (7) is provided on the outside of the heating sleeve (8). The bottom side of the protective cover (7) is fixedly connected to the top side of the base (1). The front end of the protective cover (7) is fixedly connected to the outside of the fixed flange (15).

4. The injection molding device for metal powder metallurgy production according to claim 2, characterized in that, The variable cross-section control flange (27) is fixedly connected to the top and bottom sides of the transition connecting block (26). The end of the transition connecting block (26) away from the variable cross-section control flange (27) is fixedly connected to the outside of the piston sleeve (25). The piston sleeve (25) and the transition connecting block (26) are provided with an inert fluid flow channel (20) that communicates with the high-temperature silicone oil inner cavity (19). The high-temperature silicone oil inner cavity (19) and the driving pressure chamber (22) are connected through the inert fluid flow channel (20).

5. The injection molding device for metal powder metallurgy production according to claim 4, characterized in that, The end of the inert fluid channel (20) away from the high-temperature silicone oil cavity (19) passes through the pressure relief cavity (21), and the pressure relief cavity (21) is connected to the driving pressure cavity (22).

6. The injection molding device for metal powder metallurgy production according to claim 1, characterized in that, The piston sleeve (25) is fixed with a flow box (9) on the outside, and the flow box (9) is provided with a plurality of feeding flow channels (28) on the inside; the side wall of the extrusion sleeve (16) is provided with a feeding inlet (29) that communicates with the feeding flow channel (28), and the inner wall of the variable cross section control flange (27) is provided with a feeding outlet (24) that communicates with the end of the feeding flow channel (28) away from the feeding inlet (29).

7. The injection molding device for metal powder metallurgy production according to claim 6, characterized in that, The variable cross-section control flange (27) also has a throat storage cavity (30) inside, the feeding outlet (24) is connected to the throat storage cavity (30), and one end of the sliding control slider (23) extends into the throat storage cavity (30).

8. The injection molding device for metal powder metallurgy production according to claim 1, characterized in that, The variable cross-section control flange (27) is fixedly connected to a stable section barrel (17) on the side away from the extrusion sleeve (16). The stable section barrel (17) has a stable material storage chamber (34) and a throat discharge chamber (35) inside. The stable section barrel (17) is fixedly connected to a connecting flange (33) at the end away from the variable cross-section control flange (27). A fixed mold (32) is fixedly connected to the outside of the connecting flange (33). A moving mold (6) abuts against the outside of the fixed mold (32). The moving mold (6) is slidably connected to the top side of the base (1).

9. An injection molding process for metal powder metallurgy production, applied to an injection molding apparatus for metal powder metallurgy production according to any one of claims 1-8, characterized in that: The injection molding process includes the following steps: Feeding and preheating: Metal powder enters the inner feeding sleeve (12) from the hopper (2) and finally enters the feeding screw (13). The material in the extrusion sleeve (16) is melted by the heating sleeve (8). Hydraulic kinetic energy is transmitted synchronously, and the electromagnetic pulse generator (5) drives the feeding screw (13) to pulsate axially. The screw piston head (18) at the end of the screw synchronously compresses the medium in the high-temperature silicone oil inner cavity (19), and transmits the pulse pressure to the driving pressure chamber (22) with zero delay through the inert fluid flow channel (20). The linkage valve anti-suction control is used. When the feeding screw (13) moves forward with a pulse, the hydraulic pushes the sliding control slider (23) to extend axially and actively adjust the Venturi section of the throat storage chamber (30) to accelerate the material conveying. When the feeding screw (13) moves backward with a pulse to reset, the sliding control slider (23) synchronously links to close or reduce the channel, cuts off and offsets the instantaneous negative pressure generated by the screw retraction, and locks the material in the rear stable storage chamber (34) to prevent it from being sucked backward. The shearing flow channel is pressurized in a reciprocating manner. During the reciprocating pulsation of the feeding screw (13), the suction and extrusion action of the screw piston head (18) simultaneously applies reverse reciprocating pressure to the metal powder material in multiple feeding flow channels (28), so that the material is fully kneaded and mixed under shearing force. Stable injection molding eliminates pulsating negative pressure. The material flow rate in the stable storage cavity (34) tends to be stable. Then, it is passively conical pressurized by the secondary Venturi effect of the end throat discharge cavity (35). Finally, it is injected into the cavity formed by the fixed mold (32) and the moving mold (6) for molding.

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