High-precision injection mold for engineering plastic transmission part and manufacturing process of high-precision injection mold

Abstract

The invention relates to the technical field of injection molds, in particular to a high-precision injection mold for an engineering plastic transmission part and a manufacturing process thereof, and the high-precision injection mold comprises a lower mold assembly, a spring connecting rod, a mold core assembly, an upper mold assembly and a guide column; the spring connecting rod is installed on the lower die assembly, the die core assembly is installed on the lower die assembly, the upper die assembly is installed on the die core assembly, and the guide column is installed in the lower die assembly and penetrates through the die core assembly and the upper die assembly. Injection molding is conducted on the interior of the mold core assembly through the injection molding runner formed in the mold core assembly, and demolding is conducted through the mold guide block arranged below the upper mold assembly after the engineering plastic transmission part is formed.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molds, and particularly relates to a high-precision injection mold for engineering plastic transmission parts and its manufacturing process. Background Art

[0002] Engineering plastic transmission parts are a type of functional components used in mechanical transmission systems, and are widely used in fields such as automobiles, household appliances, industrial equipment, medical devices, and office equipment. These transmission parts usually include gears, sprockets, pulleys, cams, etc., and are mainly used to replace traditional metal transmission parts to reduce weight, cost, noise, and improve wear resistance and corrosion resistance. Compared with metal parts, engineering plastic transmission parts have good self-lubrication, wear resistance, impact resistance, and a lower coefficient of friction, and are suitable for high-efficiency and lightweight mechanical transmission systems. Engineering plastic transmission parts are mainly manufactured by injection molding process, which uses high-temperature molten plastic and injects it into the mold cavity, and the final product is obtained after cooling. Since transmission parts usually require high precision, high strength, and high wear resistance, their injection molding process poses high requirements for materials, mold design, and processing accuracy.

[0003] In the injection molding process of existing molds, production is usually carried out by forming one or two workpieces at a time. The main problems of this method are low production efficiency and difficulty in meeting the needs of mass production. Long production cycle: Only one or two workpieces can be formed each time of injection molding, resulting in less output per unit time and affecting the overall production efficiency. Low equipment utilization rate: The number of mold cavities that can be operated by the injection molding machine each time is limited, resulting in the underutilization of the machine's production capacity and increasing production costs. High labor and energy consumption costs: Due to the small number of formed parts each time, more production cycles are required to complete mass production, increasing the number of manual operations and energy consumption costs. Difficulty in adapting to large-scale demand: For large-scale production requirements, this method cannot meet the requirements of rapid delivery, which may affect the market competitiveness of enterprises.

[0004] In view of the above situation, in order to overcome the above technical problems, the present invention designs a high-precision injection mold for engineering plastic transmission parts and its manufacturing process, which solves the above technical problems. Summary of the Invention

[0005] The technical objective to be achieved by the present invention is: to design a high-precision injection mold for engineering plastic transmission parts and its manufacturing process, which solves the problem that in the injection molding process of existing molds, production is usually carried out by forming one or two workpieces at a time, improves production efficiency, and can meet the needs of mass production.

[0006] In order to achieve the above technical objective, the present invention provides the following technical solutions:

[0007] A high-precision injection mold for engineering plastic transmission parts, mainly including key components such as lower mold assembly, spring connecting rod, mold core assembly, upper mold assembly and guide column. The mold structure is exquisitely designed to ensure high-precision molding of engineering plastic transmission parts, improve production efficiency and product quality.

[0008] The spring connecting rod is installed above the lower mold assembly to assist positioning and buffering, optimize the mold closing and demolding process, and prevent the mold from being subjected to excessive impact. The core assembly is fixed above the lower mold assembly. As the core component of injection molding, it has a cavity that precisely matches the shape of the transmission part to ensure the high precision of the molded product. The upper mold assembly is located above the core assembly and is responsible for closing the mold and applying the necessary pressure to ensure that the plastic melt is fully filled in the mold cavity.

[0009] In addition, the guide column is installed in the lower mold assembly, and passes through the mold core assembly and the upper mold assembly in turn, to ensure the precise alignment of the mold and prevent the mold from being misaligned during mold closing or injection molding. During the injection molding process, the molten plastic enters the cavity inside the mold core assembly through the injection runner. After filling and cooling, the guide module under the upper mold assembly assists in the demoulding operation, so that the product can be smoothly removed from the mold cavity, thereby realizing efficient and stable molding of engineering plastic transmission parts.

[0010] The lower mold assembly is mainly composed of a lower mold plate, a molding recess and an intercepting ring groove, and the various components cooperate with each other to ensure high-precision molding of the engineering plastic transmission part.

[0011] The overall structure of the lower mold plate adopts a circular design, which helps the mold to bear force evenly, improves the service life of the mold, and enhances the stability of the molding process. The upper surface of the lower mold plate is provided with a molding concave portion, the shape and size of which are precisely processed according to the design requirements of the transmission parts to ensure that the plastic melt can be accurately filled during the injection molding process and form a product contour that meets the specifications.

[0012] In addition, an intercepting ring groove is arranged around the outer side of the molding concave part. The function of the ring groove is to effectively limit the flow range of the plastic melt and prevent the occurrence of overflow, thereby ensuring the neatness and dimensional accuracy of the product edge, improving the yield rate and the reliability of the mold.

[0013] The number of the molding recesses is designed to be 2n2, where n is in the range of 2-4, that is, the number of the molding recesses can be adjusted according to specific needs to adapt to engineering plastic transmission parts of different specifications and production requirements. The structural design fully considers the flow characteristics of the molten plastic during the injection molding process to optimize the filling effect, improve production efficiency and product quality.

[0014] Specifically, the arrangement of the forming recesses is a rectangular array layout. Initially, n2 forming recesses are evenly distributed in the central area of the lower die surface to form a regular rectangular array. Subsequently, an additional circle of forming recesses is provided at each outer edge of the rectangle, bringing the final total to 2n2. This layout can ensure that the molten plastic flows evenly along multiple channels during the injection molding process, avoiding defects such as insufficient filling, weld lines, or air bubbles caused by overly long or uneven flow paths.

[0015] Through the above optimized arrangement of the forming recess design, the molten plastic can be more evenly distributed in the mold cavity during the injection molding process, improving the forming stability, ensuring the consistency of the products, further enhancing the overall forming efficiency and finished product quality, and effectively reducing the scrap rate.

[0016] The mold core assembly mainly consists of three parts: the mold core plate, the mold core platform, and the forming through slots. Each component cooperates with each other to ensure the precise forming of the engineering plastic transmission parts and optimize the material flow and mold maintenance during the injection molding process.

[0017] Among them, the mold core plate, as the basic part of the mold core assembly, is fixedly installed above the lower mold assembly. Its main function is to provide stable support and a necessary closed structure for the forming recesses to ensure that the plastic melt can evenly fill the mold cavity during injection molding. The mold core platform is installed above the mold core plate, and its diameter value is set to 0.9 times the diameter of the mold core plate. This size design forms a stepped structure, which not only helps to optimize the flow path of the molten plastic but also prevents excessive material from remaining on the mold surface, thereby reducing the cleaning difficulty and improving the production efficiency.

[0018] In addition, the forming through slots are opened at the joint of the mold core plate and the mold core platform. Their function is to ensure that the plastic melt can smoothly fill into each forming area and provide an exhaust channel to reduce defects such as air bubbles and weld lines that may occur during the injection molding process. Through such structural optimization, the mold core assembly can improve the cleaning convenience and service life of the mold while ensuring the product quality.

[0019] The mold core plate mainly includes three parts: the injection molding runner, the split runner, and the connecting runner. They jointly constitute a reasonable runner design to ensure that the molten plastic can be smoothly and evenly distributed during the injection molding process, improving the forming efficiency and product quality.

[0020] Among them, the injection molding runner is located in the central area of the mold core plate. As the main flow channel of the plastic melt, it is used to guide the molten plastic entering from the injection molding machine nozzle and transport it to multiple split channels, thus ensuring the efficient filling of the raw materials. One end of the split runner is connected to the injection molding runner, and the other end leads to the nearest forming through slot, enabling the plastic melt to quickly flow into each mold cavity and avoiding the problem of uneven filling.

[0021] In addition, the connecting runner is arranged between adjacent forming through grooves to assist the balanced flow of the plastic melt between different forming areas. However, for the forming through grooves that form an internal rectangular array on the mold core plate, no connecting runner is arranged between them. This design can prevent excessive plastic melt from flowing in, ensure the uniformity of filling in each mold cavity, and avoid flow interference and the generation of weld lines, thereby further improving the forming quality and product consistency.

[0022] The mold core table is composed of an overflow ring groove, a cross ring groove, and a peripheral ring groove. The reasonable layout of these ring grooves helps to optimize the flow path of the molten plastic during injection molding, improve the forming quality, and reduce the accumulation of excess material.

[0023] Among them, the overflow ring groove is located outside the forming through groove, mainly used to collect the excess plastic that may overflow during injection molding, prevent it from entering the non-forming area, thereby keeping the edge of the product clean and improving the forming accuracy. The cross ring groove is arranged in the middle of the forming through grooves arranged in a rectangle. This structure helps to balance the flow of the plastic melt in the mold cavity, reduce weld lines, and improve the overall quality and mechanical properties of the product.

[0024] In addition, the peripheral ring groove adopts a circumferential array method and is evenly distributed on the inner edge of the mold core table. This structure helps to control the flow direction of the molten plastic, make the material filling more uniform, improve the exhaust effect at the same time, and reduce the generation of defects such as air bubbles.

[0025] The peripheral ring groove is set to be quasi-triangular, and the sharp corners of the quasi-triangular shape are set to be arc-shaped. The quasi-triangular structure helps to guide the molten plastic to flow in a specific direction, make the filling more uniform, reduce the flow dead corners, and improve the forming quality. Secondly, the arc-shaped design at the sharp corners can effectively reduce the plastic flow resistance, reduce stress concentration, and avoid material retention or defects caused by the accumulation of pressure at the sharp corners. In addition, this design can also optimize the exhaust effect, reduce the residual air bubbles, improve the density and strength of the product, and extend the service life of the mold at the same time.

[0026] The upper mold assembly is composed of an upper template, a guiding groove, a telescopic groove, an overflow block, and a guiding module. Each part cooperates with each other to ensure the smooth progress of the injection molding process.

[0027] First of all, the upper template is installed on the top of the mold core assembly, playing a supporting and fixing role. The guiding groove is opened on the periphery of the upper template, and its function is to guide the flow of fluid or gas in the mold and ensure the accurate docking of the mold. The telescopic groove is opened in the middle of the guiding groove and has an adjustable function. It can be telescoped as needed to facilitate the adjustment of the mold position.

[0028] The overflow block is set in the middle of the upper template. This component is used to handle the excess materials that may occur during the injection molding process, ensuring that the overflowed plastic can be discharged in time, thus avoiding the accumulation of plastic and the generation of unnecessary waste, and improving the forming accuracy and efficiency.

[0029] Finally, the guide module is installed under the upper template, which is used to accurately guide the up and down movement of the mold, ensure the correct docking position of each component, and improve the operation accuracy and stability of the mold. Through these reasonable designs, the entire injection molding process is smoother and more accurate, greatly improving the production efficiency and product quality.

[0030] A manufacturing process for a high-precision injection mold for engineering plastic transmission parts, which is used to manufacture the above-mentioned high-precision injection mold for engineering plastic transmission parts; the steps of the process are as follows:

[0031] S1: The lower template and the upper template are the basic structures of the mold. They are processed by CNC according to the design drawings. During processing, key parts such as guide grooves and telescopic grooves are accurately milled to ensure the flatness and fitting accuracy of the templates. During the processing, attention should be paid to the strength and rigidity of the templates. After completion, dimensional inspection is required to ensure compliance with the design requirements;

[0032] S2: The forming recess and the core table are the core forming parts of the mold, with complex shapes. The electrical discharge machining technology is used, and through the way of electrode discharge, the complex contours of the recess and the table are accurately machined, especially for small parts such as the intercepting ring groove and the peripheral ring groove. During processing, the discharge parameters need to be controlled to ensure that the surface roughness meets the requirements and avoid excessive subsequent polishing work;

[0033] S3: The overflow ring groove and the cross ring groove are the key structures in the mold for controlling the plastic flow and overflow. Wire cutting is required to ensure its accuracy. Wire cutting uses a thin metal wire for discharge cutting. During processing, attention should be paid to the cutting speed and wire diameter selection to ensure that the groove width and depth meet the design requirements and avoid material deformation at the same time;

[0034] S4: The injection runner and the split runner are the channels for the plastic to enter the cavity. Their design directly affects the quality of injection molding. Through CNC machining, the shape and size of the runner are accurately milled to ensure smooth plastic flow and reduce pressure loss. During processing, attention should be paid to the surface finish of the runner to avoid burrs and residues, and at the same time ensure a smooth transition between the connecting runner and the cavity to reduce plastic retention and defects;

[0035] S5: After the processing of each component is completed, preliminary assembly is carried out to check the fitting conditions of components such as the lower template, the upper template, and the core plate. Focus on checking the centering accuracy of the forming through groove and the forming recess, as well as the functionality of the overflow block and the guide module. Local trimming may be required during the assembly process, such as grinding or adjustment, to ensure that each component can be closely fitted and avoid flash or mold clamping during the injection molding process.

[0036] The beneficial effects of the present invention are as follows:

[0037] (1) The high-precision injection mold for engineering plastic transmission parts and its manufacturing process designed by the present invention have remarkable beneficial effects. This invention not only solves the problem of low efficiency in the injection molding process of existing molds, where usually one or two workpieces are molded at a time, but also optimizes the production efficiency, providing strong technical support for mass production. The production efficiency is improved. Traditional injection molds can usually only mold a small number of workpieces each time. In such a production mode, when it comes to mass production, the efficiency drops significantly, wasting a large amount of production time. However, through the reasonable design of the mold structure, the present invention can mold more workpieces at the same time, greatly shortening the production cycle and significantly enhancing the production efficiency. By molding multiple workpieces simultaneously, more production tasks can be completed within the same time, improving the overall efficiency of the production line, reducing the unit cost, and being especially suitable for the requirements of large-scale production.

[0038] (2) The present invention optimizes the structural design of the mold, improving the precision and consistency of the products. In the process of multiple molding of traditional molds, due to the insufficiently precise design of the mold structure, it may lead to inconsistent product sizes and low molding precision. The present invention adopts a high-precision mold design and an optimized manufacturing process, enabling each workpiece to maintain consistent quality and dimensional accuracy during the production process, solving the problem of quality fluctuations that are prone to occur in traditional molds during mass production. By precisely controlling the material flow and temperature distribution during the injection process, the high precision and high consistency of the molded parts are ensured. The service life and stability of the mold are improved. The mold designed by the present invention uses advanced materials and processes, which not only ensure the precision of the mold but also improve its durability. In the long-term high-frequency production of traditional molds, due to material fatigue or wear, the mold precision often decreases, and even damage may occur. However, the high-strength materials and scientific heat treatment processes adopted by the present invention enable the mold to maintain stable performance during long-term operation, extending the service life of the mold and reducing the maintenance cost and downtime caused by mold damage or wear.

[0039] (3) The present invention reduces waste of raw materials. In traditional injection molding processes, due to relatively low forming precision, there are often high rates of defective products, resulting in waste of raw materials. However, the present invention improves forming precision and stability through optimized mold design, reduces the defective rate, and decreases unnecessary waste of raw materials, which helps enterprises reduce costs and improve the utilization rate of raw materials. It has strong adaptability and meets the requirements of large-scale production. The injection mold designed in the present invention has excellent adaptability and can be flexibly adjusted according to the sizes and shapes of different workpieces to meet diverse production requirements. Whether for small-batch production or large-batch production, this mold can operate efficiently and stably, thus providing enterprises with a wider range of production options. The high-precision injection mold and its manufacturing process designed in the present invention provide a more efficient, precise, and reliable solution for injection production in modern industry by improving production efficiency, optimizing the mold structure, extending the service life of the mold, reducing waste of raw materials, and providing strong adaptability. Description of the Drawings

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Now, the above and other aspects of the present invention will be described only by way of example with reference to the drawings, where:

[0042] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0043] Figure 2 is an exploded view of the components of the present invention;

[0044] Figure 3 is a schematic diagram of the structure of the lower mold assembly of the present invention;

[0045] Figure 4 is a schematic diagram of the structure of the mold core assembly of the present invention;

[0046] Figure 5 is a sectional view of the mold core assembly of the present invention;

[0047] Figure 6 is the present invention Figure 4 in a partially enlarged view;

[0048] Figure 7 is a schematic diagram of the structure of the upper mold assembly of the present invention;

[0049] Figure 8 is a schematic diagram of the structure of the upper mold assembly from another perspective of the present invention.

[0050] In the figure: 1. Lower die assembly; 11. Lower template; 12. Forming recess; 13. Intercepting annular groove; 2. Spring connecting rod; 3. Core assembly; 31. Core plate; 311. Injection runner; 312. Dividing runner; 313. Connecting runner; 32. Core platform; 321. Overflow annular groove; 322. Cross annular groove; 323. Peripheral annular groove; 33. Forming through groove; 4. Upper die assembly; 41. Upper template; 42. Guide groove; 43. Telescopic groove; 44. Overflow block; 45. Guide module; 5. Guide post. Specific embodiments

[0051] To better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0052] As Figure 1-8 shown, a high-precision injection mold for engineering plastic transmission parts mainly includes key components such as a lower die assembly 1, a spring connecting rod 2, a core assembly 3, an upper die assembly 4, and a guide post 5. The mold has a delicate structure design, which can ensure the high-precision molding of engineering plastic transmission parts, improve production efficiency and product quality.

[0053] Among them, the spring connecting rod 2 is installed above the lower die assembly 1, playing an auxiliary positioning and buffering role to optimize the mold closing and demolding processes and prevent the mold from being impacted too much. The core assembly 3 is fixed above the lower die assembly 1 and serves as the core component of injection molding. A cavity that precisely matches the shape of the transmission part is provided inside it to ensure the high precision of the molded product. The upper die assembly 4 is located above the core assembly 3 and is responsible for mold closing and applying necessary pressure to ensure the full filling of the plastic melt in the mold cavity.

[0054] In addition, the guide post 5 passes through the lower die assembly 1 and successively passes through the core assembly 3 and the upper die assembly 4, which is used to ensure the precise alignment of the mold and prevent the mold from being misaligned during mold closing or injection molding. During the injection process, the molten plastic enters the cavity inside the core assembly 3 through the injection runner 311. After filling and cooling and solidifying, the guide module 45 below the upper die assembly 4 assists in the demolding operation, enabling the product to be smoothly taken out of the mold cavity, thereby realizing the efficient and stable molding of engineering plastic transmission parts.

[0055] The lower die assembly 1 mainly consists of a lower template 11, a forming recess 12, and an intercepting annular groove 13. Each component cooperates with each other to ensure the high-precision molding of engineering plastic transmission parts.

[0056] Among them, the overall structure of the lower template 11 adopts a circular design. This shape helps the mold to be stressed evenly, improves the service life of the mold, and enhances the stability of the molding process. The upper surface of the lower template 11 is provided with a molding recess 12, and the shape and size of this recess are precisely machined according to the design requirements of the transmission part to ensure that the plastic melt can be accurately filled during the injection molding process and form a product profile that meets the specifications.

[0057] In addition, an intercepting ring groove 13 is arranged around the outer side of the molding recess 12. The function of this ring groove is to effectively limit the flow range of the plastic melt, prevent the occurrence of overflow, thereby ensuring the cleanliness and dimensional accuracy of the product edge, and improving the finished product rate and the reliability of mold use.

[0058] As Figure 3 shown, the number of the molding recesses 12 is designed to be 2n², where the value range of n is 2 - 4, that is, the number of the molding recesses 12 can be adjusted according to specific requirements to adapt to engineering plastic transmission parts of different specifications and production requirements. This structural design fully considers the flow characteristics of the molten plastic during the injection molding process to optimize the filling effect, improve the production efficiency and product quality.

[0059] Specifically, the arrangement of the molding recesses 12 is a rectangular array layout. Initially, n² molding recesses 12 are evenly distributed in the central area of the lower die surface to form a regular rectangular array. Subsequently, an additional circle of molding recesses 12 is arranged on each outer edge of this rectangle, so that the final total number reaches 2n². This layout can ensure that the molten plastic flows evenly along multiple channels during the injection molding process, avoiding defects such as insufficient filling, weld lines or bubbles caused by too long or uneven flow paths.

[0060] Through the above optimized arrangement design of the molding recesses 12, the molten plastic can be more evenly distributed in the mold cavity during the injection molding process, improving the molding stability, ensuring the consistency of the products, further enhancing the overall molding efficiency and finished product quality, and effectively reducing the scrap rate.

[0061] As Figure 4 shown, the mold core assembly 3 is mainly composed of a mold core plate 31, a mold core table 32 and a molding through groove 33. Each component cooperates with each other to ensure the precise molding of the engineering plastic transmission part and optimize the material flow and mold maintenance during the injection molding process.

[0062] Among them, the core plate 31, as the basic part of the core assembly 3, is fixedly installed above the lower die assembly 1. Its main function is to provide stable support and provide a necessary closed structure for the forming recess 12 to ensure that the plastic melt can uniformly fill the mold cavity during injection molding. The core table 32 is installed above the core plate 31, and its diameter value is set to 0.9 times the diameter of the core plate 31. This size design forms a stepped structure, which not only helps to optimize the flow path of the molten plastic but also prevents excessive material from remaining on the mold surface, thereby reducing the cleaning difficulty and improving the production efficiency.

[0063] In addition, the forming through groove 33 is opened at the joint of the core plate 31 and the core table 32. Its function is to ensure that the plastic melt can smoothly fill into each forming area and at the same time provide an exhaust channel to reduce defects such as bubbles and weld lines that may occur during the injection molding process. Through such structural optimization, the core assembly 3 can improve the cleaning convenience and service life of the mold while ensuring the quality of the product.

[0064] As Figure 5 shown, the core plate 31 mainly includes three parts: the injection molding runner 311, the split runner 312, and the connecting runner 313. They jointly constitute a reasonable runner design to ensure that the molten plastic can be smoothly and uniformly distributed during the injection molding process, improving the molding efficiency and the quality of the product.

[0065] Among them, the injection molding runner 311 is located in the central area of the core plate 31. As the main flow channel of the plastic melt, it is used to guide the molten plastic entering from the injection machine nozzle and transport it to multiple split channels, thus ensuring the efficient filling of the raw materials. One end of the split runner 312 is connected to the injection molding runner 311, and the other end leads to the nearest forming through groove 33, enabling the plastic melt to quickly flow into each mold cavity and avoiding the problem of uneven filling.

[0066] In addition, the connecting runner 313 is arranged between adjacent forming through grooves 33 to assist the balanced flow of the plastic melt between different forming areas. However, for the forming through grooves 33 that form an internal rectangular array on the core plate 31, no connecting runner 313 is provided between them. This design can prevent excessive plastic melt from flowing in, ensure the uniformity of filling in each mold cavity, and avoid flow interference and the generation of weld lines, thereby further improving the molding quality and product consistency.

[0067] As Figure 6 shown, the core table 32 is composed of an overflow ring groove 321, a cross ring groove 322, and a peripheral ring groove 323. The reasonable layout of these ring grooves helps to optimize the flow path of the molten plastic during the injection molding process, improve the molding quality, and reduce the accumulation of excess material.

[0068] Among them, the overflow ring groove 321 is located outside the forming through groove 33 and is mainly used to collect the excess plastic that may overflow during the injection molding process, preventing it from entering the non-forming area, thereby keeping the edge of the product clean and improving the forming accuracy. The cross ring groove 322 is arranged in the middle of the rectangularly arranged forming through groove 33. This structure helps to balance the flow of the plastic melt in the mold cavity, reduce weld lines, and improve the overall quality and mechanical properties of the product.

[0069] In addition, the peripheral ring groove 323 is arranged in a circumferential array and evenly distributed on the inner edge of the mold core table 32. This structure helps to control the flow direction of the molten plastic, make the material filling more uniform, improve the exhaust effect at the same time, and reduce the generation of defects such as air bubbles.

[0070] The peripheral ring groove 323 is set to be triangular-like, and the sharp corners of the triangular-like shape are set to be arc-shaped. The triangular-like structure helps to guide the molten plastic to flow in a specific direction, make the filling more uniform, reduce the dead corners of flow, and improve the forming quality. Secondly, the arc-shaped design at the sharp corners can effectively reduce the flow resistance of the plastic, reduce stress concentration, and avoid material retention or defects caused by the accumulation of pressure at the sharp corners. In addition, this design can also optimize the exhaust effect, reduce the residual air bubbles, improve the density and strength of the product, and extend the service life of the mold at the same time.

[0071] As Figure 7 shown, the upper mold assembly 4 is composed of an upper template 41, a guide groove 42, a telescopic groove 43, an overflow block 44, and a guide module 45. Each part cooperates with each other to ensure the smooth progress of the injection molding process.

[0072] First of all, the upper template 41 is installed on top of the mold core assembly 3, playing a supporting and fixing role. The guide groove 42 is opened on the periphery of the upper template 41, and its function is to guide the flow of fluid or gas in the mold and ensure the accurate docking of the mold. The telescopic groove 43 is opened in the middle of the guide groove 42 and has an adjustable function, which can be telescoped as needed to facilitate the adjustment of the mold position.

[0073] The overflow block 44 is arranged in the middle of the upper template 41. This component is used to handle the excess material that may appear during the injection molding process, ensure that the overflowing plastic can be discharged in time, thereby avoiding the accumulation of plastic and the generation of unnecessary waste, and improving the forming accuracy and efficiency.

[0074] Finally, the guide module 45 is installed under the upper template 41 and is used to accurately guide the up and down movement of the mold, ensure the correct docking position of each component, and improve the operation accuracy and stability of the mold at the same time. Through these reasonable designs, the entire injection molding process is smoother and more accurate, greatly improving the production efficiency and product quality.

[0075] A manufacturing process for a high-precision injection mold for engineering plastic transmission parts, which is used to manufacture the above-mentioned high-precision injection mold for engineering plastic transmission parts; the steps of the process are as follows:

[0076] S1: The lower template 11 and the upper template 41 are the basic structures of the mold. They are processed by CNC according to the design drawings. During processing, key parts such as the guide groove 42 and the telescopic groove 43 are precisely milled to ensure the flatness and mating accuracy of the templates. During the processing, attention should be paid to the strength and rigidity of the templates. After completion, dimensional inspection is required to ensure compliance with the design requirements;

[0077] S2: The forming recess 12 and the core table 32 are the core forming parts of the mold, with complex shapes. Using electrical discharge machining technology, through the way of electrode discharge, the complex contours of the recess and the table are precisely machined, especially for small parts such as the intercepting ring groove 13 and the peripheral ring groove 323. During processing, the discharge parameters need to be controlled to ensure that the surface roughness meets the requirements and avoid excessive subsequent polishing work;

[0078] S3: The overflow ring groove 321 and the cross ring groove 322 are key structures in the mold for controlling the flow and overflow of plastics. Wire cutting is required to ensure their accuracy. Wire cutting uses a thin metal wire for discharge cutting. During processing, attention should be paid to the cutting speed and wire diameter selection to ensure that the groove width and depth meet the design requirements and avoid material deformation at the same time;

[0079] S4: The injection runner 311 and the sub-runner 312 are the channels for plastics to enter the cavity. Their design directly affects the quality of injection molding. Through CNC processing, the shape and size of the runner are precisely milled to ensure smooth plastic flow and reduce pressure loss. During processing, attention should be paid to the surface finish of the runner to avoid burrs and residues. At the same time, ensure that the transition between the connecting runner 313 and the cavity is smooth to reduce plastic retention and defects;

[0080] S5: After the processing of each component is completed, preliminary assembly is carried out to check the mating conditions of components such as the lower template 11, the upper template 41, and the core plate 31. Focus on checking the centering accuracy of the forming through groove 33 and the forming recess 12, as well as the functionality of the overflow block 44 and the guide module 45. Local trimming may be required during the assembly process, such as grinding or adjustment, to ensure that each component can be closely mated and avoid flash or mold clamping during the injection process.

[0081] During the working process of the present invention, the liquid engineering plastic enters the core plate 31 through the injection runner, and fills all the forming through grooves 33 through the sub-runner 312 and the connecting runner 313. The upper mold assembly 4 moves down to the specified position, and the overflowing part of the raw material will stay in the overflow ring groove 321, the cross ring groove 322, and the peripheral ring groove 323; after waiting for cooling and forming, under the limit guidance of the guide post 5, the guide module 45 pushes out the formed transmission part to realize demolding.

[0082] For those of ordinary skill in the art, various modifications to the present disclosure will be apparent, and the general principles defined herein can be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but should be accorded the broadest scope consistent with the principles and novel features disclosed herein. Although one or more exemplary embodiments of the present disclosure have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A high-precision injection mold for engineering plastic transmission parts, characterized in that: It comprises a lower die assembly (1), a spring connecting rod (2), a core die assembly (3), an upper die assembly (4) and a guide column (5); The spring connecting rod (2) is mounted on the top of the lower mold assembly (1), the core assembly (3) is mounted on the top of the lower mold assembly (1), the upper mold assembly (4) is mounted on the top of the core assembly (3), and the guide column (5) is mounted in the lower mold assembly (1) and is arranged through the core assembly (3) and the upper mold assembly (4); injection molding is performed into the core assembly (3) through the injection flow channel (311) opened in the core assembly (3), and after the engineering plastic transmission part is molded, demoulding is performed using the guide module (45) arranged below the upper mold assembly (4).

2. A high-precision injection mold for engineering plastic transmission parts according to claim 1, characterized in that: The lower mold assembly (1) comprises a lower mold plate (11), a molding recess (12) and an intercepting ring groove (13); The lower template (11) is arranged in a circular shape, the molding concave portion (12) is arranged on the upper surface of the lower template (11), and the intercepting ring groove (13) is arranged around the outer side of the molding concave portion (12).

3. A high-precision injection mold for engineering plastic transmission parts according to claim 2, characterized in that: The number of the molding recesses (12) is set to 2n 2 and n is 2-4.

4. A high-precision injection mold for engineering plastic transmission parts according to claim 3, characterized in that: The molding concave portion (12) is first provided with n 2 The plurality of molds are arranged in a rectangular array in the middle of the lower mold surface, and each outer side of the rectangle is provided with a molding concave portion (12).

5. The high-precision injection mold for engineering plastic transmission parts according to claim 1, characterized in that: The core mold assembly (3) comprises a core mold plate (31), a core mold table (32) and a molding through groove (33); The core plate (31) is mounted on the top of the lower mold assembly (1), the core platform (32) is mounted on the top of the core plate (31), the diameter of the core platform (32) is set to 0.9 times the diameter of the core plate (31), and the molding groove (33) is opened in the middle of the core plate (31) and the core platform (32).

6. A high-precision injection mold for engineering plastic transmission parts according to claim 5, characterized in that: The core plate (31) comprises an injection flow channel (311), a branch flow channel (312) and a connecting flow channel (313); The injection channel (311) is opened in the middle of the core plate (31); one end of the branch channel (312) is connected to the injection channel (311), and the other end is connected to the molding groove (33) closest to the injection channel (311); the connecting channel (313) is opened between adjacent molding grooves (33), and the molding grooves (33) forming an internal rectangular array are not provided with connecting channels (313) with each other.

7. The high-precision injection mold for engineering plastic transmission parts according to claim 5, characterized in that: The core platform (32) comprises an overflow ring groove (321), a cross ring groove (322) and a peripheral ring groove (323); The overflow annular groove (321) is provided outside the forming through groove (33), the cross annular groove (322) is provided in the middle of the rectangular part of the forming through groove (33), and the peripheral annular groove (323) is provided in a circular array on the inner edge of the core platform (32).

8. The high-precision injection mold for engineering plastic transmission parts according to claim 7, characterized in that: The peripheral annular groove (323) is configured to be quasi-triangular, and the sharp corner of the quasi-triangular shape is configured to be arc-shaped.

9. The high-precision injection mold for engineering plastic transmission parts according to claim 1, characterized in that: The upper mold assembly (4) comprises an upper mold plate (41), a guide groove (42), a telescopic groove (43), an overflow block (44) and a guide module (45); The upper template (41) is installed on the top of the core assembly (3), the guide groove (42) is opened on the periphery of the upper template (41), the telescopic groove (43) is opened in the middle of the guide groove (42), the overflow block (44) is arranged in the middle of the upper template (41), and the guide module (45) is installed below the upper template (41).

10. A manufacturing process for a high-precision injection mold for an engineering plastic transmission part, the process being used to manufacture a high-precision injection mold for an engineering plastic transmission part according to any one of claims 1 to 9; characterized in that: The steps of the process are as follows: S1: The lower template (11) and the upper template (41) are the basic structure of the mold. According to the design drawings, they are processed by CNC. During processing, the key parts such as the guide groove (42) and the telescopic groove (43) are accurately milled to ensure the flatness and matching accuracy of the template. During the processing, attention should be paid to the strength and rigidity of the template. After completion, the size inspection is required to ensure that it meets the design requirements; S2: The molding concave portion (12) and the core table (32) are the core molding parts of the mold, and have complex shapes. The complex contours of the concave portion and the table are accurately machined by using the electric spark machining technology through electrode discharge. In particular, the intercepting ring groove (13) and the peripheral ring groove (323) are small parts. During machining, the discharge parameters need to be controlled to ensure that the surface roughness meets the requirements and avoid excessive subsequent polishing workload; S3: The overflow ring groove (321) and the cross ring groove (322) are key structures in the mold for controlling the flow and overflow of plastic. Their accuracy needs to be ensured by wire cutting. Wire cutting uses thin metal wires for discharge cutting. During processing, attention should be paid to the selection of cutting speed and wire diameter to ensure that the groove width and depth meet the design requirements and avoid material deformation. S4: The injection runner (311) and the diversion runner (312) are channels for plastic to enter the cavity. Their design directly affects the quality of injection molding. Through CNC processing, the shape and size of the runner are accurately milled to ensure smooth plastic flow and reduce pressure loss. During processing, attention should be paid to the surface finish of the runner to avoid burrs and residues. At the same time, ensure that the transition between the connecting runner (313) and the cavity is smooth to reduce plastic retention and defects. S5: After the processing of each component is completed, preliminary assembly is carried out to check the matching of the lower mold plate (11), the upper mold plate (41), the core plate (31) and other components, with a focus on checking the centering accuracy of the molding groove (33) and the molding recess (12), as well as the functionality of the overflow block (44) and the guide module (45). Local trimming, such as grinding or adjustment, may be required during the assembly process to ensure that the components can fit closely and avoid flash or mold jamming during the injection molding process.

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