Injection molding device based on powder metallurgy material processing molding and injection molding method thereof

Abstract

The invention discloses an injection molding device based on powder metallurgy material processing and forming and an injection molding method of the injection molding device, and relates to the technical field of powder metallurgy material processing and forming. The injection molding device comprises a lathe bed, a mold assembly, a glue inlet runner, a cooling assembly, an exhaust groove and an ejection assembly; the movable mold assembly and the fixed mold assembly are closed to form a cavity; the glue inlet runner is arranged on the fixed mold assembly and communicates with the mold cavity, the cooling assembly is arranged on the movable mold assembly, the cooling assembly is arranged around the mold cavity, and the cooling assembly is used for cooling and shaping formed in the mold cavity; the exhaust groove is formed in the mold assembly and used for exhausting volatile gas generated in the filling process of the powder adhesive. The ejection assembly is arranged on the movable mold assembly, and the ejection assembly is used for pushing out or separating a formed part from the cavity; the problems of unstable forming quality, low cooling efficiency, incomplete exhaust and the like of the powder metallurgy material in the machining and forming process can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy material processing and forming technology, and in particular to an injection molding device and injection molding method based on powder metallurgy material processing and forming. Background Technology

[0002] Currently, electrical cabinet keys on the market are mainly manufactured using three processing methods. The first method is injection molding, where molten plastic granules are injected into a mold and cooled for a few seconds to solidify. However, plastic keys produced this way are prone to deformation under stress due to the material's properties, and have poor temperature resistance, making them susceptible to wear and breakage, failing to meet the requirements for long-term use and mechanical strength. The second method is stamping and machining, which can produce more precise metal keys, such as those made of stainless steel. However, due to the complex processing steps, low output per batch, and long production cycle, production efficiency is low. The third method is die casting, where molten aluminum ingots are injected into a mold and then cooled to solidify. While this method can produce metal keys, it suffers from issues with precision and surface treatment. Key products often exhibit burrs, glue runner defects, and require additional polishing to improve surface finish. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide an injection molding device based on powder metallurgy material processing to solve the technical problems of low precision, poor temperature resistance, and easy wear of keys processed in the prior art.

[0004] To achieve the above objectives, the present invention provides an injection molding apparatus based on powder metallurgy material processing, comprising a machine bed, a mold assembly, a runner, a cooling assembly, a venting groove, and an ejection assembly. The mold assembly is mounted on the machine bed and includes a moving mold assembly and a fixed mold assembly. The moving mold assembly and the fixed mold assembly close together to form a cavity. The cavity is used to form an injection mold composed of a mixture of metal powder and binder. The runner is disposed on the fixed mold assembly and communicates with the cavity. The runner includes a main runner and branch runners. The main runner is used to receive the molten metal powder and binder powder. The runner is used to evenly distribute the powder melt into the cavity. The runner is connected to the main runner and forms a gradually diffusing fan-shaped gate. The cross-sectional area of ​​the gate gradually increases from the main runner towards the cavity. The cooling assembly is disposed on the moving mold assembly and surrounds the cavity. The cooling assembly is used to cool and solidify the molded part in the cavity. The venting groove is disposed on the mold assembly and is used to discharge the volatile gases generated by the powder binder during the filling process. The ejection assembly is disposed on the moving mold assembly and is used to push or separate the molded part from the cavity.

[0005] Based on the above embodiments, the moving mold assembly includes a moving template and a moving mold core. The moving template is installed on the bed, and the moving mold core is installed on the moving template. The moving template is used to drive the moving mold core to close with the fixed mold assembly.

[0006] Based on the above embodiments, the fixed mold assembly includes a fixed template and a fixed mold core, the fixed template is installed on the bed, and the fixed mold core is installed on the fixed template.

[0007] Based on the above embodiments, the moving model core precisely aligns with the fixed model core during mold closing to form the cavity.

[0008] Based on the above embodiments, the injection molding device further includes a core slider and an inclined guide post. The core slider is slidably disposed on the moving mold assembly or the fixed mold assembly, and the inclined guide post is fixedly disposed on the mold assembly opposite to the core slider. The inclined guide post cooperates with the inclined guide surface of the core slider for the movement and guidance of the core slider.

[0009] Based on the above embodiments, the injection molding device further includes an ejector pin, which is disposed on the core slider. After the mold is closed, the ejector pin extends into the cavity and is used to form a keyhole structure for the lock core during the injection molding process. It remains fixed and does not retract before the mold is opened to prevent the flow of the powder melt from causing the keyhole structure to deform or close.

[0010] Based on the above embodiments, the injection molding device further includes an ejector pin position detection component, which is disposed on the core slider. The ejector pin position detection component is used to output a high-level signal to the injection molding device to confirm that the ejector pin has completed reset, and the injection molding device is only allowed to perform subsequent mold closing or injection actions after receiving the high-level signal. If the injection molding device does not receive the high-level signal, subsequent actions are prohibited.

[0011] Based on the above embodiments, the exhaust groove has a groove depth of 0.01 to 0.08 mm and a groove width of 2 to 6 mm, and the exhaust groove is arranged in a matrix grid or ring shape.

[0012] Based on the above embodiments, the cooling assembly includes at least two independent temperature control zones, and each temperature control zone is equipped with a temperature sensor and a cooling flow regulating valve to achieve zoned temperature control of the cavity.

[0013] Based on the above embodiments, the injection molding device further includes a mold locking buckle, which is disposed on the fixed mold assembly. The mold locking buckle enters a locking state after the mold is closed, which is used to enhance the mold closing force and prevent the mold parting surface from opening slightly during the high-pressure injection stage.

[0014] Based on the above embodiments, an injection molding machine screw barrel is used to plasticize, mix and meter metal powder and binder, and inject the powder melt of metal powder and binder mixture into the glue inlet channel of the injection molding device as described in any one of claims 1-10.

[0015] Based on the above embodiments, an automatic processing device for removing the injection nozzle is provided, which is used to automatically cut off and separate the injection nozzle formed at the end of the product by the injection molding device as described in any one of claims 1-10 to form a finished product.

[0016] Another aspect of the present invention provides an injection molding method based on powder metallurgy material processing, which utilizes the apparatus described in the above embodiments and includes the following steps: S1: Control the injection molding device to perform the mold closing action, so that the moving mold assembly and the fixed mold assembly close to form a cavity. Then, the metal powder and binder powder melt processed by the injection molding machine screw and barrel are injected into the cavity through the main channel and the branch channel, so that the powder melt fills and forms the structure to be molded. S2: After injection molding is completed, the cavity is cooled to allow the powder melt to gradually solidify and form a green part. Then, the ejection assembly is controlled to push the green part out of the cavity. S3: Cleaning and degreasing the green parts to remove organic binders from the material and form a brown blank with a porous structure; S4: The brown blank is placed in a sintering furnace to heat up and disperse the residual binder and promote the bonding of metal particles. S5: After sintering is completed, the sprue head is removed by an automatic processing device to remove the sprue head of the part in order to obtain the final metal product.

[0017] Compared with existing technologies, this invention has beneficial effects. By setting up a glue inlet channel with a gradient diffusion structure, the powder melt formed by metal powder and binder flows more uniformly and stably during the filling process, effectively reducing the probability of uneven filling, jetting, and internal defects. By arranging cooling components around the cavity, the temperature field distribution during the molding process is more balanced, which is beneficial to improving the dimensional stability of the green blank and reducing internal stress concentration, thereby improving the dimensional accuracy and mechanical properties of the final sintered product. The reasonable structure and size of the venting groove can timely discharge the volatile gases of the powder binder during the filling process, reducing trapped gas, scorching, and surface defects, further improving the appearance quality and internal density of the product. This invention can obtain metal key products with high density, good wear resistance, excellent temperature resistance, and high dimensional consistency. Compared with traditional plastic injection molding, machining, or die casting methods, it significantly reduces processing steps and manual intervention, improves production efficiency, and reduces overall manufacturing costs. It is suitable for the large-scale manufacturing of metal functional parts such as electrical cabinet keys with high requirements for strength, precision, and service life. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an injection molding apparatus according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the cooling assembly according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the glue inlet flow channel according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the final part obtained after processing by the automatic processing device for removing the glue head in an embodiment of the present invention.

[0023] Figure Labels Mold assembly 10, moving mold assembly 11, moving template 111, moving mold core 112, fixed mold assembly 12, fixed template 121, fixed mold core 122, injection runner 20, main runner 21, branch runner 22, cooling assembly 30, venting groove 40, ejection assembly 50, core slider 60, inclined guide pillar 61, ejector pin 62, ejector pin position detection assembly 63, mold lock buckle 70. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0026] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or end that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or ends.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] An injection molding apparatus based on powder metallurgy material processing includes a bed, a mold assembly 10, a runner 20, a cooling assembly 30, a venting channel 40, and an ejection assembly 50. The mold assembly 10 is mounted on the bed and includes a moving mold assembly 11 and a fixed mold assembly 12. The moving mold assembly 11 and the fixed mold assembly 12 close to form a cavity for molding an injection mold composed of a mixture of metal powder and binder. The runner 20 is disposed on the fixed mold assembly 12 and communicates with the cavity. The runner 20 includes a main runner 21 and branch runners 22. The main runner 21 is used to receive the metal powder and binder. The powder melt is distributed evenly into the cavity via a runner 22. The runner 22 connects to the main runner 21 and forms a gradually diffusing fan-shaped gate, with the cross-sectional area of ​​the gate gradually increasing from the main runner 21 towards the cavity. The cooling assembly 30 is disposed on the moving mold assembly 11 and surrounds the cavity. The cooling assembly 30 is used to cool and solidify the molded part within the cavity. The venting groove 40 is disposed on the mold assembly 10 and is used to discharge the volatile gases generated during the filling process of the powder binder. The ejector assembly 50 is disposed on the moving mold assembly 11 and is used to push or separate the molded part from the cavity.

[0030] Furthermore, the moving mold assembly 11 includes a moving template 111 and a moving mold core 112. The moving template 111 is mounted on the bed, and the moving mold core 112 is mounted on the moving template 111. The moving template 111 is used to drive the moving mold core 112 to close with the fixed mold assembly 12.

[0031] Furthermore, the fixed mold assembly 12 includes a fixed template 121 and a fixed mold core 122. The fixed template 121 is mounted on the bed, and the fixed mold core 122 is mounted on the fixed template 121.

[0032] Specifically, during the injection molding process, the moving mold core 112 moves towards the fixed mold and completes the mold closing action. The fixed mold core 122 is installed on the fixed mold plate 121 and is used to form a cavity with the moving mold core 112.

[0033] Furthermore, the injection molding device also includes a core slider 60 and an inclined guide post 61. The core slider 60 is slidably mounted on the moving mold assembly 11 or the fixed mold assembly 12. The inclined guide post 61 is fixedly mounted on the mold assembly 10 opposite to the core slider 60. The inclined guide post 61 cooperates with the inclined guide surface of the core slider 60 for the movement and guidance of the core slider 60.

[0034] Furthermore, the injection molding device also includes an ejector pin 62, which is disposed on the core slider 60. After the mold is closed, the ejector pin 62 extends into the cavity and is used to form the keyhole structure of the lock core during the injection molding process. It remains fixed and does not retract before the mold is opened to prevent the flow of powder melt from causing the keyhole structure to deform or close.

[0035] Furthermore, the injection molding device also includes an ejector pin position detection component 63, which is disposed on the core slider 60. The ejector pin position detection component 63 is used to output a high-level signal to the injection molding device to confirm that the ejector pin 62 has completed the reset, and the injection molding device is only allowed to perform subsequent mold closing or injection actions after receiving the high-level signal.

[0036] Specifically, the core slider 60 is slidably mounted on the moving mold assembly 11 or the fixed mold assembly 12, and the inclined guide post 61 is fixedly mounted on the mold assembly 10 opposite to the core slider 60. The inclined surface structure of the inclined guide post 61 cooperates with the inclined guide surface on the core slider 60, forming a mechanical drive relationship through mold opening and closing. During mold closing, the inclined guide post 61 enters the guide groove of the core slider 60 and pushes the core slider 60 to move towards the cavity area, so that the core slider 60 and the mold core together form a complete molding structure. During mold opening, the inclined guide post 61 moves in the opposite direction and drives the core slider 60 out of the lateral area of ​​the cavity, so that the lateral structure of the part is separated from the molding surface, avoiding damage or deformation of the part due to interference.

[0037] Specifically, the injection molding device includes an ejector pin 62, which is mounted on the core slider 60 and moves synchronously with it. After mold closing, the ejector pin 62 extends into the cavity and forms the keyhole structure of the lock core during the injection and holding pressure stages. It remains fixed and does not retract throughout the entire molding cycle to ensure that the keyhole structure does not close, shift, or deform due to pressure during the filling process of the powder metallurgy material.

[0038] Specifically, the injection molding device includes an ejector pin position detection component 63, which is mounted on the core slider 60. The ejector pin position detection component 63 detects whether the ejector pin 62 has retracted to the preset reset position and outputs a corresponding electrical signal. When the ejector pin 62 completes the reset and triggers the detection signal, the system outputs a high-level signal to the injection molding device. The injection molding device is only allowed to perform subsequent mold closing or injection actions after receiving the high-level confirmation signal. If no high-level signal is detected, the execution of the next action is prevented, thereby avoiding mold interference, core collision or equipment damage caused by the ejector pin 62 not retracting.

[0039] Furthermore, the exhaust groove 40 has a groove depth of 0.01 to 0.08 mm and a groove width of 2 to 6 mm, and the exhaust groove 40 is arranged in a matrix grid or ring shape.

[0040] Specifically, the venting groove 40 is connected to the mold cavity. During the process of the injected powder melt entering the mold cavity and flowing towards the end area, the venting groove 40 is used to guide the air mixed in the powder melt, residual binder volatiles and a small amount of venting pressure, so that the filling channel forms a continuous venting path.

[0041] By arranging the venting grooves 40 at the end of the cavity and in corner areas prone to gas accumulation, low-pressure venting outlets can be formed during the advancement of the powder melt, thereby preventing the formation of a gas-sealed layer at the front end of the melt. This structure effectively reduces trapped gas, scorching, and material shortage at the end, improves the flow and ductility of the powder metallurgy melt, enables the material to achieve a complete forming state, improves the density of the product, and ensures consistent dimensional accuracy and surface quality at the mold end.

[0042] like Figure 2 As shown, this structure adopts a ring-shaped cooling water channel layout, where positions ① and ② are ring-shaped cooling water channels arranged around the product molding area. This ring-shaped cooling water channel is continuously distributed along the circumference of the product cavity, expanding the cooling area of ​​the mold cavity. The cooling fluid circulates in a ring within the channel, achieving uniform temperature transfer around the mold cavity. This method ensures that the powder metallurgy material melt achieves a stable and consistent cooling rate during molding and cooling processes, avoiding dimensional deviations, cooling marks, or stress concentrations caused by insufficient or excessive cooling in localized areas.

[0043] Locations ③ and ④ are equipped with dedicated cooling water channels for the main flow channel 21 and the product injection system. These cooling water channels also employ a circumferential layout to control the temperature in the main flow channel 21 area, maintaining the injection area within a suitable temperature range for the flow of the powder and binder system. This structure reduces binder phase separation, instability, or flowability changes caused by temperature differences during injection, thereby ensuring a consistent viscosity of the melt at multiple flow points and improving the continuity of powder system flow and filling stability within the mold cavity.

[0044] Positions ⑤ and ⑥ are the core area of ​​the product. After the powder melt formed by the mixture of metal powder and binder enters the core area through the injection channel, it is cooled and solidified under the action of the annular cooling structure, making the temperature field more uniform during the molding process. This cooling layout helps to shorten the cooling cycle, increase the injection cycle time, and reduce defects such as warping, cracks, or shrinkage marks caused by uneven thermal expansion and contraction in powder metallurgy products.

[0045] The aforementioned annular cooling water channel structure enables independent temperature control between the injection area and the product molding area, resulting in a more uniform temperature distribution throughout the injection and cooling process, thereby improving the dimensional stability, surface quality, and mechanical reliability of powder metallurgy products.

[0046] Furthermore, the injection molding device also includes a mold clamping buckle 70, which is disposed on the fixed mold assembly 12. The mold clamping buckle 70 enters a locking state after the mold is closed, which is used to enhance the mold closing force and prevent the mold parting surface from opening slightly during the high-pressure injection stage.

[0047] Specifically, the mold clamping buckle 70 provides auxiliary mold clamping during the injection filling process of powder metallurgy materials by applying additional clamping force to the closed area of ​​the mold, thereby counteracting the expansion force generated by the powder melt on the mold parting surface during the high-pressure injection stage. This structure effectively prevents the mold parting surface from slightly opening or depressurizing, avoids the powder melt from leaking from the cavity edge or generating burrs, and improves the mold closing rigidity and cavity geometric stability.

[0048] It can also enable the mold to maintain a stable fit clearance under high pressure injection conditions, improve the consistency of part dimensions and molding accuracy, further reduce cracks, burrs or part defects caused by micro-molding, and improve the molding quality and production reliability of powder metallurgy materials.

[0049] Furthermore, the screw barrel of the injection molding machine is used to convey, plasticize, mix, and meter the metal powder and binder mixture to form a powder melt with good flowability and uniform dispersion. The screw barrel is connected to the injection flow channel 20 of the injection molding device through the injection mechanism. After metering, the powder melt is injected into the main flow channel 21 and the branch flow channel 22 under set pressure, speed, and temperature conditions to fill the mold cavity and form a green product.

[0050] After molding, the end of the part typically forms a sprue head that connects to the main runner 21. An automated sprue head removal processing device is used to automatically cut off and separate the residual structure from the end of the molded part and the gate.

[0051] Another aspect of the present invention provides an injection molding method based on powder metallurgy material processing, comprising the following steps: S1: Control the injection molding device to perform the mold closing action, so that the moving mold assembly 11 and the fixed mold assembly 12 close to form a cavity. Then, the metal powder and binder powder melt processed by the injection molding machine screw and barrel are injected into the cavity through the main channel 21 and the branch channel 22, so that the powder melt fills and forms the structure to be molded. S2: After injection molding is completed, the cavity is cooled to allow the powder melt to gradually solidify and form a green blank. Then, the ejection assembly 50 is controlled to push the green blank out of the cavity. S3: Cleaning and degreasing the green parts to remove organic binders from the material and form a brown blank with a porous structure; S4: The brown blank is placed in a sintering furnace to heat up and disperse the residual binder and promote the bonding of metal particles. S5: After sintering is completed, the sprue head is removed by an automatic processing device to remove the sprue head of the part in order to obtain the final metal product.

[0052] In Example 1, the mold assembly 10 includes a moving mold assembly 11 and a fixed mold assembly 12. The moving mold assembly 11 reciprocates along the opening and closing direction. The moving mold assembly 11 includes a moving template 111 and a moving mold core 112. The moving mold core 112 is installed on the moving template 111 to cooperate with the fixed mold core 122 to form a cavity.

[0053] The fixed mold assembly 12 is installed on the fixed end of the bed and includes a fixed template 121 and a fixed mold core 122. The fixed mold core 122 is fixed on the fixed template 121 and together with the moving mold core 112, forms a cavity.

[0054] During the mold closing process, the moving template 111 moves toward the fixed template 121 until the moving template core 112 and the fixed template core 122 are precisely closed and positioned to ensure that the cavity contour forms a complete structure.

[0055] An injection molding system is also provided on one side of the mold. The injection molding system includes a main runner 21, a branch runner 22, and a product inlet. The main runner 21 is arranged opposite to the injection molding machine nozzle and is used to receive the molten metal powder injected by the injection molding machine nozzle. The downstream of the main runner 21 is connected to the branch runner 22, and the branch runner 22 is connected to the inlet of each product cavity. In this embodiment, the product inlet preferably adopts a fan-shaped gate structure, so that the powder metallurgy material melt flows more smoothly and evenly when entering the cavity, reducing jetting and filling defects.

[0056] In this embodiment, a molten material inlet channel 20 is provided. The molten material inlet channel 20 is located inside the fixed mold assembly 12 and is connected to the injection molding machine screw and barrel. The molten material inlet channel 20 includes a main channel 21 and a branch channel 22. The main channel 21 is responsible for receiving the powdered melt from the injection molding machine screw and barrel, and the branch channel 22 is used to transport the melt to different areas of the cavity, thereby ensuring uniform filling.

[0057] The runner 22 adopts a gradient diffusion fan-shaped gate design, which makes the powder metallurgy material melt flow more smoothly and evenly when entering the cavity, reducing jetting and filling defects.

[0058] Cooling components 30 are arranged on the moving mold assembly 11, and are spaced apart in a ring-shaped water channel structure around the cavity. The cooling water channel adopts a ring-shaped layout to ensure that the cavity wall obtains uniform heat exchange conditions during the molding cycle, avoiding warping, dimensional deviations, shrinkage cavities and surface defects caused by uneven heating and cooling.

[0059] In this embodiment, the cooling component 30 was optimized to address the problems of uneven temperature distribution and insufficient cooling efficiency during the injection molding process of powder metallurgy materials.

[0060] like Figure 2A first annular cooling water channel and a second annular cooling water channel are arranged around the product cavity. Figures ① and ② show the annular cooling water channels arranged circumferentially around the product core. These annular cooling water channels form a closed or nearly closed ring structure along the outer periphery of the product core, allowing the cooling medium to flow continuously circumferentially around the product core. This ensures uniform cooling of the main body area of ​​the product after the powder metallurgy material melt has filled the cavity. This annular cooling water channel design effectively avoids localized overcooling or overheating phenomena present in traditional linear or localized cooling methods, resulting in a more balanced and stable overall temperature decrease of the product core. This helps reduce problems such as uneven molding shrinkage, internal stress concentration, and dimensional deviations.

[0061] Figures ③ and ④ show annular cooling water channels surrounding the injection runner 20. These channels are arranged around the main runner 21 and the injection area to continuously cool the area through which the high-temperature melt flows during the injection and holding pressure stages. This balances the temperature gradient between the main runner 21 and the product cavity, preventing feed degradation, flow instability, or defects in the injection gate area caused by excessively high injection system temperatures. By implementing annular cooling of the main runner 21 system, the injection system temperature becomes more stable, which helps ensure consistent filling of each product cavity in a multi-cavity mold.

[0062] This embodiment features a venting groove 40 structure, machined on the mold parting surface. The venting groove 40 has a depth of 0.01–0.08 mm and a width of 2–6 mm, arranged in a matrix grid or ring pattern. This allows the gas carried by the flow front to be discharged promptly during injection, preventing gas compression and the formation of flow obstruction areas. It also prevents scorching spots, incomplete filling, short material, and carbonization defects, thereby improving the product's appearance and internal density stability. After molding, the part needs to be removed from the cavity. The ejector assembly 50 is mounted on the moving mold assembly 11, evenly pushing the cooled and molded part out of the cavity, preventing breakage, tearing, or deformation due to uneven local draft forces. The device also includes a core slider 60, which can slide linearly along a guide rail. An inclined guide post 61 is fixedly mounted on the mold assembly 10 structure opposite the slider. When the device performs the mold closing action, the moving platen 111 drives the inclined guide post 61 to move forward. The inclined guide post 61 and the guide inclined surface of the core slider 60 generate an interaction force, causing the core slider 60 to move towards the cavity and enter the molding position. Correspondingly, a core slider 60 and an inclined guide post 61 are also provided on the side of the fixed platen 121.

[0063] Ejector pin 62 is mounted on core slider 60. After the mold closes, ejector pin 62 enters the cavity and forms a keyhole structure inside the product during injection. Ejector pin 62 remains locked during injection to prevent melt backflow from causing geometric deformation or hole closure.

[0064] To ensure the safety and reliability of the operational logic, an ejector pin position detection component 63 is provided in this embodiment. This component 63 is mounted on the core slider 60 and provides the current position status of the ejector pin 62 to the injection molding device via signal feedback. When the detection component sends a high-level signal, the injection molding device allows subsequent injection or mold closing actions; if the positioning state is not reached, the system is prohibited from continuing operation to prevent mold collision, damage, or part shape deviation caused by the ejector pin 62 not resetting.

[0065] To ensure the structural stability of the mold during the high-pressure injection stage, a mold locking buckle 70 is provided in this embodiment, which is installed on the fixed mold assembly 12. After the mold is closed, the mold locking buckle 70 enters the locking state, providing additional structural clamping force to the mold and preventing the parting surface from opening or slightly shifting during the high-pressure injection stage.

[0066] This device is used in conjunction with the screw and barrel of an injection molding machine. The screw and barrel are used for conveying, plasticizing, and mixing metal powder and binder materials. To further improve post-molding processing efficiency, this embodiment includes an automatic sprue removal device. This device automatically cuts off the sprue at the end of the part. The part is fed into the positioning fixture by the conveying mechanism, and the machining tool performs fixed-distance cutting to ensure a smooth cut surface that does not affect the part's geometry and mechanical properties. This processing method replaces manual cutting, enabling precise control of finishing accuracy, reducing the risk of processing damage, and is suitable for batch continuous production.

[0067] The device operates as follows: First, the mold closing action is performed, causing the moving mold assembly 11 and the fixed mold assembly 12 to close and form a cavity. The powder melt is then injected into the main runner 21 and branch runner 22 via the injection molding machine screw and barrel, ultimately entering the cavity area. The material undergoes pressure holding and stable flow within the mold, and is then solidified by the cooling assembly 30. After solidification, the ejector assembly 50 ejects the part from the cavity. The part then undergoes a cleaning and degreasing process to remove internal binders, forming a porous blank. The blank then enters a sintering furnace, where sintering is completed through temperature control at each stage, causing the metal powder particles to combine and form a dense structure. After sintering, the part enters the sprue removal device for machining, ultimately obtaining a finished metal part that meets the required dimensions and structural specifications. Through the structural design and process control of this embodiment, stable injection molding of high-viscosity powder metallurgy systems can be achieved, improving mold life, part quality consistency, and batch manufacturing capabilities. It also boasts advantages such as strong structural adaptability, high part precision, and high reliability.

[0068] Specifically, in the injection preparation stage, the pre-prepared metal powder and binder are mixed in a set ratio to form an injection feed, which is then added to the screw barrel of the injection molding machine. The feed is plasticized, mixed and metered by the rotation and heating of the screw, so that it forms a powder melt with good flowability.

[0069] The injection molding device performs a mold closing action, causing the moving mold assembly 11 and the fixed mold assembly 12 to close and precisely align to form a cavity. After confirming that components such as the ejector pin 62 and the core slider 60 are in the set positions, the powder melt is injected into the cavity through the main runner 21 and the branch runner 22 under the action of injection pressure. Under the guidance of the gradient diffusion gate, the powder melt evenly fills the cavity and forms the structure to be molded.

[0070] In this embodiment, hydraulic or all-electric injection molding equipment is used. The processing temperature range of the injection molding equipment is generally 160℃~220℃, the mold temperature range is generally 50℃~130℃, the injection pressure range is generally 500bar~2500bar, the holding time range is generally 0.5s~20s, the injection cavity pressure range is generally 500bar~2000bar, the injection speed is 10mm / s~150mm / s, the screw plasticizing speed is 1m / min-5m / min, and the screw plasticizing back pressure range is generally 2-30bar. The powder melt is injected into the cavity according to the above molding process.

[0071] In this embodiment, preferably, the injection molding machine barrel temperature is 200°C, the moving and fixed mold temperatures are 70°C, the injection pressure is 1400 bar, the holding time is 3 seconds, the injection cavity pressure is 500 bar, the injection speed is 40 mm / s, the screw plasticizing speed is 3 m / min, and the screw plasticizing back pressure is 15 bar.

[0072] After injection, the mold enters the holding and cooling stage. The cavity is continuously cooled by the cooling component 30 set inside the mold, so that the powder melt gradually solidifies and forms a green part with a certain strength. After cooling, the mold is opened and the ejection component 50 is driven to push the formed green part out of the cavity smoothly.

[0073] The green blanks after demolding are cleaned to remove residual mold release agent or impurities from their surface. Then, the green blanks are degreased by solvent extraction, thermal degreasing, or a combination of both to gradually remove the organic binders inside the green blanks, thereby obtaining a brown blank with a connected pore structure.

[0074] The brown blank is placed in a sintering furnace and heated and held under a controlled atmosphere according to a preset heating curve. This further disperses the residual binder and promotes diffusion bonding between metal powder particles to form a dense metallurgical structure, thus completing the sintering process.

[0075] In the later stages of sintering, ideally, the pores slow down the movement of grain boundaries, inhibiting grain growth; this is known as grain boundary locking. However, if the pores move too slowly, the grain boundaries will separate from the pore boundaries, which will actually accelerate grain growth.

[0076] As the sintering process continues, the particle boundaries become smoother, and the ability to remove pores from the particles weakens. At this point, small pores (a large number of vacancies concentrated on the particle surface) gradually form large pores (fewer pores concentrated) through aggregation. This causes pore roughening, that is, the number of small pores decreases and the number of large pores gradually increases. Compared with making the grains coarser (less particle boundary movement), applying force to obtain high density will cause the pores to shrink rapidly.

[0077] Therefore, the particle growth rate is related to the sintering temperature, and the temperature most conducive to particle densification is below the temperature required for separation between particle boundaries and pore boundaries. In the sintering and forming of iron-based metal composites, boron, copper, silicon, titanium, and other elements are often added as sintering aids to improve the degree of sintering of the product.

[0078] In the final sintering stage, porosity can be eliminated through a slow volumetric diffusion process. High density can be achieved through vacuum sintering or soluble gas sintering. Although small pores can lead to large pores, particle growth (such as pore size and particle boundaries) can be controlled by selecting the thermal cycle and material composition, ensuring that the pore size is below 5 μm. Microstructure analysis can examine the distribution of particles and pores. The microstructure can be used to adjust and optimize the sintering process to achieve the best product condition.

[0079] After sintering and cooling, the sintered part is removed, and the glue inlet at the end of the part is cut off and separated by an automatic glue inlet removal device to obtain a final metal product with high dimensional accuracy, stable mechanical properties and meeting the requirements for use.

[0080] The method described in this embodiment is continuous and controllable, and can effectively realize the mass production of powder metallurgy metal products from injection molding to the final product. It is suitable for metal key products with high requirements for structural precision, wear resistance and temperature resistance.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An injection molding device based on powder metallurgy material processing, characterized in that, include: Bed frame; A mold assembly mounted on the bed, the mold assembly including a moving mold assembly and a fixed mold assembly, the moving mold assembly and the fixed mold assembly closing to form a cavity, the cavity being used to form an injection mold composed of a mixture of metal powder and binder; A sprue is provided on the fixed mold assembly and is connected to the cavity. The sprue includes a main runner and branch runners. The main runner is used to receive the powder melt of metal powder and binder. The branch runners are used to evenly distribute the powder melt to the cavity. The branch runners are connected to the main runner and form a gradually diffusing fan-shaped gate. The cross-sectional area of ​​the gate gradually increases from the main runner towards the cavity. A cooling assembly is disposed on the moving mold assembly and surrounds the cavity. The cooling assembly is used to cool and solidify the molded part within the cavity. An exhaust channel is provided on the mold assembly and is used to discharge volatile gases generated by the powder binder during the filling process; An ejector assembly is disposed on the moving mold assembly and is used to eject or separate the molded part from the cavity.

2. The injection molding apparatus according to claim 1, characterized in that, The moving mold assembly includes a moving template and a moving mold core. The moving template is mounted on the bed, and the moving mold core is mounted on the moving template. The moving template is used to drive the moving mold core to close with the fixed mold assembly.

3. The injection molding apparatus according to claim 2, characterized in that, The fixed mold assembly includes a fixed template and a fixed mold core. The fixed template is installed on the bed, and the fixed mold core is installed on the fixed template.

4. The injection molding apparatus according to claim 3, characterized in that, The moving mold core precisely aligns with the fixed mold core during mold closing to form the cavity.

5. The injection molding apparatus according to claim 4, characterized in that, The injection molding device further includes a core slider and an inclined guide post. The core slider is slidably disposed on the moving mold assembly or the fixed mold assembly. The inclined guide post is fixedly disposed on the mold assembly opposite to the core slider. The inclined guide post cooperates with the inclined guide surface of the core slider for the movement and guidance of the core slider.

6. The injection molding apparatus according to claim 5, characterized in that, The injection molding device also includes an ejector pin, which is disposed on the core slider. After the mold is closed, the ejector pin extends into the cavity and is used to form the keyhole structure of the lock core during the injection molding process. It remains fixed and does not retract before the mold is opened to prevent the flow of powder melt from causing the keyhole structure to deform or close.

7. The injection molding apparatus according to claim 6, characterized in that, The injection molding device also includes an ejector pin position detection component, which is disposed on the core slider. The ejector pin position detection component is used to output a high-level signal to the injection molding device to confirm that the ejector pin has completed the reset, and the injection molding device is only allowed to perform subsequent mold closing or injection actions after receiving the high-level signal. If the injection molding device does not receive the high-level signal, subsequent actions are prohibited.

8. The injection molding apparatus according to claim 1, characterized in that, The exhaust groove has a depth of 0.01 to 0.08 mm and a width of 2 to 6 mm, and the exhaust groove is arranged in a matrix grid or ring shape.

9. The injection molding apparatus according to claim 1, characterized in that, The cooling assembly includes at least two independent temperature control zones, and each temperature control zone is equipped with a temperature sensor and a cooling flow regulating valve to achieve zoned temperature control of the cavity.

10. The injection molding apparatus according to claim 9, characterized in that, The injection molding device also includes a mold locking buckle, which is disposed on the fixed mold assembly. The mold locking buckle enters a locking state after the mold is closed, which is used to enhance the mold closing force and prevent the mold parting surface from opening slightly during the high-pressure injection stage.

11. A screw barrel for an injection molding machine, characterized in that, The injection molding machine screw barrel is used to plasticize, mix and meter the metal powder and binder, and to inject the powder melt of the mixture of metal powder and binder into the injection flow channel of the injection molding device as described in any one of claims 1-10.

12. An automatic processing device for removing adhesive feed head, characterized in that, The automatic processing device for removing the injection nozzle is used to automatically cut off and separate the injection nozzle formed at the end of the product by the injection molding device as described in any one of claims 1-10 to form a finished product.

13. An injection molding method based on powder metallurgy material processing, using the apparatus described in any one of claims 1-12. Includes the following steps: S1: Control the injection molding device to perform the mold closing action, so that the moving mold assembly and the fixed mold assembly close to form a cavity. Then, the metal powder and binder powder melt processed by the injection molding machine screw and barrel are injected into the cavity through the main channel and the branch channel, so that the powder melt fills and forms the structure to be molded. S2: After injection molding is completed, the cavity is cooled to allow the powder melt to gradually solidify and form a green part. Then, the ejection assembly is controlled to push the green part out of the cavity. S3: Cleaning and degreasing the green parts to remove organic binders from the material and form a brown blank with a porous structure; S4: The brown blank is placed in a sintering furnace to heat up and disperse the residual binder and promote the bonding of metal particles. S5: After sintering is completed, the sprue head is removed by an automatic processing device to remove the sprue head of the part in order to obtain the final metal product.

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