An integrated injection molding method and injection molding mold for an aluminum alloy and plastic

Abstract

The application relates to the technical field of integrated injection molding, and discloses an integrated injection molding method and injection mold for aluminum alloy and plastic, which comprises the following steps: providing an aluminum alloy insert, the aluminum alloy insert is provided with an identification area and an interface locking area which are not overlapped with each other and are not at the same horizontal height, at least one through hole which penetrates through the aluminum alloy insert is formed in the identification area, and the interface locking area is subjected to surface pretreatment to obtain a pretreated aluminum alloy insert; fixing the pretreated aluminum alloy insert in a cavity of an injection mold, a first preset gap and a second preset gap are formed between the injection mold and the aluminum alloy insert, and an engineering plastic melt is injected into the cavity of the injection mold. The integrated injection molding method and injection mold for aluminum alloy and plastic improve the compactness, appearance consistency of the light-transmitting thin-wall area and the overall forming reliability of the integrated injection molded part without increasing complex control means.

Description

Technical Field

[0001] This invention relates to the field of integrated injection molding technology, specifically to an integrated injection molding method and injection mold for aluminum alloy and plastic. Background Technology

[0002] With the increasing demands for product integration and functional complexity in consumer electronics, automotive interiors and functional structural components, smart homes, and industrial equipment, integrated injection molding technology combining aluminum alloys and engineering plastics has become widely used. By combining the high strength and wear resistance of aluminum alloys with the molding flexibility and functional plasticity of engineering plastics in the same structural component, lightweight design and diverse appearance effects can be achieved while ensuring structural strength. Especially in products that require the formation of markings, functional light transmission, or partially visible areas on a metal exterior, integrated injection molding has become an important manufacturing method. However, such products typically place higher demands on the bonding strength between aluminum alloys and engineering plastics, appearance quality, and the dimensional stability and optical consistency of the light transmission areas, making the integrated injection molding process face more complex molding and quality control challenges in practical applications.

[0003] In existing integrated injection molding methods for aluminum alloys and plastics, when it is necessary to form translucent markings or thin-walled display areas on aluminum alloy structures, the process usually involves creating through holes in the aluminum alloy inserts. The engineering plastic melt directly fills the through holes during injection molding to form the translucent area. In this type of injection molding process, the engineering plastic melt usually lacks a transition or containment space that works in conjunction with the injection mold before entering the through hole. The melt often directly enters the through hole for injection or is directly injected from the thin-walled display area. Subsequently, it either connects with the mold's venting structure or enters a nearly free-expanding space. The melt flow path is abrupt and lacks buffering, which easily leads to jet flow at the through hole entrance or thin-walled display area, entraining air. At the same time, there is a lack of a relatively closed space behind the through hole to receive and constrain the melt. This makes it difficult for the engineering plastic melt entering the thin-walled area to maintain a stable flow state during injection and holding pressure, and it is also not conducive to the controlled discharge of gas. This easily leads to defects such as bubbles, silver streaks, or haze inside the translucent area, making it difficult to reliably guarantee the molding consistency and appearance quality of the translucent markings or thin-walled areas. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an integrated injection molding method and injection mold for aluminum alloy and plastic, solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] Design an integrated injection molding method for aluminum alloy and plastic, including:

[0007] S1. Provide an aluminum alloy insert, wherein the aluminum alloy insert is provided with a marking area and an interface locking area that do not overlap and are not at the same horizontal height, at least one through hole is opened in the marking area to penetrate the aluminum alloy insert, and the interface locking area is surface pretreated to obtain a pretreated aluminum alloy insert.

[0008] S2. The pretreated aluminum alloy insert is fixed in the cavity of the injection mold. A first preset gap and a second preset gap are formed between the injection mold and the aluminum alloy insert. The engineering plastic melt is injected into the cavity of the injection mold, so that the engineering plastic melt is combined with the interface locking area of ​​the pretreated aluminum alloy insert. Excess engineering plastic melt enters the first preset gap and flows out from the through hole to the second preset gap, thus obtaining an integrated injection molded part.

[0009] S3. Cool the integrated injection molded part. The engineering plastic melt entering the through hole and the first preset gap is formed into a light-transmitting thin-walled area. After cooling, demold to obtain the integrated injection molded part.

[0010] Optionally, S1 specifically includes:

[0011] S11. Provide aluminum alloy inserts, and divide the aluminum alloy inserts into marking areas and interface locking areas that do not overlap and are not at the same horizontal height.

[0012] S12. Perform through-processing in the marking area of ​​the aluminum alloy insert to form at least one through hole through the aluminum alloy insert, and deburr and round the corner of the hole wall to obtain an aluminum alloy insert with a completed through hole.

[0013] S13. On the aluminum alloy insert with completed through holes, a corrosion-resistant mask layer is applied to the surface outside the interface locking area to isolate the marking area and other areas that are not pretreated. The interface locking area is degreased and cleaned before etching to form a microgroove structure for the wetting and mechanical interlocking of engineering plastic melt. After etching, the interface locking area is neutralized, rinsed and dried to obtain a roughened interface locking area.

[0014] S14. On the aluminum alloy insert with a roughened interface locking region, remove the mask layer covering the interface locking region, and perform a drying and activation treatment on the aluminum alloy insert to obtain a pretreated aluminum alloy insert.

[0015] Optionally, S14 specifically includes:

[0016] S141. The mask layer covering the interface locking area includes one of tape or a continuous elastic film formed after coating with natural rubber. The aluminum alloy insert with the roughened interface locking area is heated at a temperature of 40-60°C for 1-3 minutes, and then the mask layer is peeled off along the boundary direction of the interface locking area at a peeling speed of 10-50 mm / s to obtain the aluminum alloy insert with the mask layer peeled off.

[0017] S142. The aluminum alloy insert after the mask layer has been peeled off is pre-dried in circulating hot air at 40-70℃ for 10-30 minutes to obtain a pre-dried aluminum alloy insert. The pre-dried aluminum alloy insert is then treated in a vacuum oven at 70-120℃ for 20-90 minutes to complete the drying and activation treatment, and a pre-treated aluminum alloy insert is obtained.

[0018] Optionally, in step S13, the etching solution used during etching includes an alkaline etching solution, which includes sodium hydroxide, sodium carbonate, and a wetting agent, and the wetting agent includes at least one of lauryl alcohol polyoxyethylene ether, cetyl alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.

[0019] Optionally, S2 specifically includes:

[0020] S21. Fix the pre-treated aluminum alloy insert at the position corresponding to the first preset gap and the second preset gap in the cavity of the injection mold, close and lock the injection mold, and form the first preset gap and the second preset gap between the pre-treated aluminum alloy insert and the cavity of the injection mold. Both the first preset gap and the second preset gap are connected to the through hole.

[0021] S22. The engineering plastic is heated and plasticized to form an engineering plastic melt. The engineering plastic melt is injected into the cavity of the injection mold according to preset parameters. After entering the cavity, the engineering plastic melt flows preferentially to the interface locking area of ​​the pretreated aluminum alloy insert. After the engineering plastic melt fills the interface locking area to form an initial bonding interface, the excess engineering plastic melt flows directionally into the first preset gap and flows out through the through hole to the second preset gap. The preset parameters include injection speed and injection pressure.

[0022] S23. By maintaining stable injection parameters during the injection molding process, the engineering plastic melt in the interface locking zone is kept under continuous pressure, resulting in an integrated injection molded part with stable flow.

[0023] Optionally, S22 specifically includes:

[0024] S221. The engineering plastic is heated and plasticized to form an engineering plastic melt. The engineering plastic melt is injected into the cavity of the injection mold at an injection speed of 20-60 mm / s and an injection pressure of 30-80 MPa. After entering the cavity, the engineering plastic melt preferentially flows to the interface locking area of ​​the pretreated aluminum alloy insert.

[0025] S222: The engineering plastic melt continuously fills the interface locking zone, forming a continuous melt cover layer in the interface locking zone, thus obtaining the initial bonding interface.

[0026] S223. After obtaining the initial bonding interface, the engineering plastic melt is adjusted to continue to be injected into the cavity of the injection mold at an injection speed of 60-150 mm / s and an injection pressure of 80-140 MPa, pushing the excess engineering plastic melt from the interface locking area to flow in a directional direction towards the first preset gap, so that the excess engineering plastic melt enters the first preset gap.

[0027] S224. The engineering plastic melt that enters the first preset gap flows further and enters the through hole. After the engineering plastic melt enters the through hole, the injection speed of the engineering plastic melt is restored to 20-60 mm / s and the injection pressure is 30-80 MPa, so that the engineering plastic melt in the interface locking zone is kept under pressure. The excess engineering plastic melt flows out through the through hole to the second preset gap.

[0028] Optionally, S3 specifically includes:

[0029] S31. Keep the injection mold in a closed, locked state to maintain the shape of the integrated injection molded part;

[0030] S32. The cavity is cooled to 40-60°C by the cooling system of the injection mold, so that the engineering plastic melt entering the through hole and the first preset gap is solidified to form a light-transmitting thin-walled area.

[0031] S33. After cooling is complete, open the injection mold and remove the integrated injection molded part from the cavity to obtain the integrated injection molded part.

[0032] An integrated injection mold for aluminum alloy and plastic is characterized by employing the integrated injection molding method for aluminum alloy and plastic as described above, comprising an upper injection mold and a lower injection mold arranged sequentially along a first direction, wherein the end face of the upper injection mold abuts against the end face of the lower injection mold, a cavity is formed between the upper injection mold and the lower injection mold, the cavity is used to place an aluminum alloy insert, and the lower injection mold is provided with a positioning groove that mates with the aluminum alloy insert.

[0033] Optionally, the upper injection mold includes an injection port, an upper mold body, a filling module, and a vacuum port. The filling module is fixedly connected to the surface of the upper mold body facing the lower injection mold and is located within the cavity. The injection port is opened on the surface of the upper mold body away from the lower injection mold and extends along a first direction through the filling module and communicates with the cavity. The vacuum port is opened on the surface of the upper mold body away from the lower injection mold and communicates with the cavity. A first preset gap is formed between the filling module and the aluminum alloy insert along a second direction. The lower injection mold includes a lower mold body, and the positioning groove is opened on the lower mold body. A second preset gap is formed between the lower injection mold and the aluminum alloy insert along the second direction.

[0034] This invention provides an integrated injection molding method and injection mold for aluminum alloy and plastic, which has the following beneficial effects:

[0035] This integrated injection molding method and mold for aluminum alloy and plastic creates a first and a second preset gap between the aluminum alloy insert and the injection mold. These gaps are connected to through-holes in the aluminum alloy insert. This allows the molten engineering plastic to enter the first preset gap before entering the through-hole during injection molding. This provides a buffer and rectification space for the melt to transition from the interface locking zone to the through-hole, preventing the melt from directly rushing into the through-hole at high speed and generating a jet flow. Simultaneously, after flowing out through the through-hole, the molten engineering plastic enters the second preset gap (the closed cavity space of the injection mold). This allows the melt to be constrained by the cavity behind the through-hole, forming a continuous and stable filling state. This facilitates the gradual release of entrained air and volatile gases as the melt flows, reducing gas retention in the light-transmitting thin-walled area. The continuous flow path—entering the first preset gap, then the through-hole, and finally flowing out into the closed cavity space (the second preset gap)—is beneficial. This process makes the molding process of engineering plastic melt in the translucent thin-walled zone more stable, reducing the occurrence of bubbles and haze. At the same time, as the injection molding process enters the middle and late stages of holding pressure, the engineering plastic melt in the marking zone cools first and its viscosity rises rapidly due to the thin-walled structure. Its ability to continue flowing through the first preset gap and through-hole gradually decreases. However, the interface locking zone, due to its thicker structure and close fit with the aluminum alloy insert, still maintains a higher temperature and plasticity, thus becoming the more dominant pressure response area in the time sequence. This allows the main holding pressure applied by the injection molding machine to gradually transform into effective static pressure in the interface locking zone, which is used to compensate for shrinkage and compact the interface of the interface locking zone. This ensures that the holding pressure mainly acts on the interface locking zone, which is beneficial to improving the bonding density and bonding strength of the engineering plastic in the interface locking zone. Thus, without increasing complex control methods, the density, appearance consistency, and overall molding reliability of the integrated injection molded part in the translucent thin-walled zone are improved. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the installation structure of the integrated injection mold of aluminum alloy and plastic in this invention;

[0037] Figure 2 This is a schematic diagram of the installation structure of the injection mold lower mold in this invention;

[0038] Figure 3 This is a three-dimensional structural diagram of the integrated injection mold of aluminum alloy and plastic in this invention;

[0039] Figure 4 This is a side cross-sectional view of the integrated injection mold of aluminum alloy and plastic in this invention.

[0040] Figure 5 This is a front cross-sectional view of the aluminum alloy insert in this invention.

[0041] In the diagram: 10. Upper injection mold; 11. Injection port; 12. Upper mold body; 13. Filling module; 14. Vacuum port; 20. Lower injection mold; 21. Positioning groove; 22. Lower mold body; 30. Cavity; 40. Aluminum alloy insert; 41. Through hole; 42. Interface locking area; 43. Marking area; 51. First preset gap; 52. Second preset gap. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0043] This invention provides a technical solution: an integrated injection molding method for aluminum alloy and plastic, comprising:

[0044] S1. Provide an aluminum alloy insert, wherein the aluminum alloy insert is provided with a marking area and an interface locking area that do not overlap and are not at the same horizontal height, at least one through hole is opened in the marking area to penetrate the aluminum alloy insert, and the interface locking area is surface pretreated to obtain a pretreated aluminum alloy insert.

[0045] In this embodiment, as a preferred option, S1 specifically includes:

[0046] S11. Provide aluminum alloy inserts, and divide the aluminum alloy inserts into marking areas and interface locking areas that do not overlap and are not at the same horizontal height.

[0047] S12. Through-hole processing is performed in the marking area of ​​the aluminum alloy insert to form at least one through-hole. The hole wall is then deburred and rounded to obtain an aluminum alloy insert with a completed through-hole. The through-hole is formed in the marking area by mechanical drilling, milling, or other hole-forming methods. This through-hole serves as a channel for the subsequent flow and molding of the engineering plastic melt. During the hole-forming process, burrs or sharp corners are easily generated at the edge of the hole wall, which can cause sudden changes in local melt flow rate, increased shear, or even gas stagnation during injection molding. Therefore, deburring and rounding are performed to address this issue. The process transforms the irregular state of the through-hole wall into a smooth and continuous curved surface structure, thereby improving the flow conditions of the melt when passing through the through-hole and reducing the probability of molding defects. Through-holes are formed by through-processing in the marked area, and the through-hole walls are deburred and rounded to give the through-holes a regular, continuous morphology without sharp edges. This reduces the risk of shearing damage or flow turbulence of the engineering plastic melt at the through-hole during subsequent injection molding. The shaping of the hole wall improves the flow stability of the melt when passing through the through-hole, which is conducive to obtaining a light-transmitting structure with a consistent appearance and a low defect rate.

[0048] S13. On the aluminum alloy insert with completed through holes, a corrosion-resistant mask layer is applied to the surface outside the interface locking zone to isolate the marking area and other areas that do not undergo surface pretreatment. The interface locking zone is then degreased and cleaned before etching to form a microgroove structure for the wetting and mechanical interlocking of the engineering plastic melt. After etching, the interface locking zone is neutralized, rinsed, and dried to obtain a roughened interface locking zone. Degreasing and cleaning remove oil, processing residues, and other organic contaminants from the surface of the interface locking zone, ensuring a clean aluminum alloy substrate surface and thus guaranteeing uniform etching. The etching process selectively dissolves the aluminum alloy surface through the etching solution, forming a microgroove and micropit structure with controllable dimensions in the interface locking zone. This microstructure provides embedding space for the engineering plastic melt during injection molding. This process achieves interface bonding primarily through mechanical locking. Neutralization and rinsing after etching terminate the etching reaction and remove residual acid and alkali media, while drying ensures the roughened interface locking area remains stable and free of liquid film, preventing interface instability in subsequent processes. By degreasing and further etching the interface locking area of ​​the aluminum alloy insert with completed through-holes, a microgroove structure is formed on the surface of the interface locking area, giving it higher surface roughness and a larger effective contact area. This significantly enhances the wetting ability and mechanical interlocking ability of the engineering plastic melt on the aluminum alloy insert during injection molding. The combined etching, neutralization, rinsing, and drying processes effectively remove residual etching media and reaction products, ensuring the stability and consistency of the roughened structure and providing a reliable foundation for obtaining a high-strength interface in subsequent integrated injection molding.

[0049] Selective processing is achieved through mask isolation. The corrosion-resistant mask layer is a protective material that can withstand subsequent degreasing, cleaning, and etching media, and can be completely peeled off after processing. Covering the surface outside the interface locking zone, it prevents direct contact between etching solutions, cleaning solutions, and other chemical media and the protected area (i.e., the marked area and other areas not undergoing surface pretreatment). By structurally distinguishing the marked area from the interface locking zone, and by applying a mask to the aluminum alloy insert surface outside the interface locking zone, subsequent processing and chemical treatments occur only within the predetermined area (interface locking zone), thus achieving selective processing of the aluminum alloy. The directional treatment of different functional areas of the gold insert involves dividing the aluminum alloy insert into non-overlapping marking areas and interface locking areas at different horizontal levels. A corrosion-resistant mask layer is then applied to the surface outside the interface locking area. This effectively isolates the subsequent surface treatment of the marking area and the interface locking area in terms of space and process, thereby avoiding interference between different processing steps. This step can precisely limit the processing range of the interface locking area while ensuring the structural integrity of the marking area. It provides a stable premise for the subsequent etching to form a controllable roughening structure, which is conducive to improving the bonding consistency between the engineering plastic and the aluminum alloy insert in the subsequent integrated injection molding process.

[0050] In step S13, the etching solution used during etching includes an alkaline etching solution, which includes sodium hydroxide, sodium carbonate, and a wetting agent. The wetting agent includes at least one of lauryl alcohol polyoxyethylene ether, hexadecyl alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether. Sodium hydroxide, as the main etching component, reacts chemically with aluminum and its surface oxide layer to produce controlled dissolution on the aluminum alloy surface, thereby forming microscale pits and trench structures. Sodium carbonate, as a buffer and stabilizing component, can adjust the alkalinity of the solution and inhibit local over-corrosion caused by excessively rapid etching reaction, making the etching process smoother and more controllable. The wetting agent is a nonionic surfactant, including at least one of lauryl alcohol polyoxyethylene ether, hexadecyl alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether. Its molecule contains polyether hydrophilic segments, which can significantly reduce the surface tension of the etching solution, allowing the etching solution to spread fully on the aluminum alloy surface and at the walls of micro-grooves and through holes, and eliminating attached air bubbles, thereby ensuring that the etching reaction is carried out uniformly on the surface of the interface locking zone.

[0051] S14. On the aluminum alloy insert with a roughened interface locking region, remove the mask layer covering the interface locking region, and perform a drying and activation treatment on the aluminum alloy insert to obtain a pretreated aluminum alloy insert.

[0052] In this embodiment, as a preferred option, S14 specifically includes:

[0053] S141. The mask layer covering the interface locking region includes one of the following: a continuous elastic film formed by coating with adhesive tape or natural rubber. An aluminum alloy insert with a roughened interface locking region is heated to a temperature of 40–60°C for 1–3 minutes, and then the mask layer is peeled off along the boundary direction of the interface locking region at a peeling speed of 10–50 mm / s to obtain an aluminum alloy insert with the mask layer completely peeled off. The mask layer is a continuous elastic film formed by coating with adhesive tape or natural rubber, and its function is to physically isolate the non-processed area during the preceding etching process. This is achieved by heating the aluminum alloy insert to 40–60°C and holding it for 1–3 minutes. After 3 minutes, the adhesion strength and elastic modulus of the mask layer material can be reduced, making it easier to peel off as a whole. Then, peeling is performed at a constant peeling speed of 10-50 mm / s along the boundary of the interface locking zone. This avoids excessive instantaneous pull-out force that could cause local peeling off of the aluminum alloy insert surface, thereby achieving smooth removal of the mask layer and maintaining the integrity of the roughened interface locking zone structure on the aluminum alloy insert surface. By subjecting the mask layer covering the interface locking zone to controlled heating and constant-speed peeling treatment, the tape or the continuous elastic film formed by coating natural rubber can be completely and smoothly removed from the surface of the aluminum alloy insert.

[0054] S142. The aluminum alloy inserts after mask layer peeling are pre-dried in circulating hot air at 40–70℃ for 10–30 min to obtain pre-dried aluminum alloy inserts. The pre-dried aluminum alloy inserts are then treated in a vacuum oven at 70–120℃ for 20–90 min to complete the drying and activation treatment, resulting in pre-treated aluminum alloy inserts. The 40–70℃ circulating hot air pre-drying is mainly used to gently remove free water and volatile solvents from the surface of the aluminum alloy inserts, avoiding liquid film migration or residue caused by excessively rapid heating. Subsequently, treatment in a vacuum oven at 70–120℃ for 20–90 min, by reducing environmental pressure and increasing temperature, allows the adsorbed material to... The bound water and low-molecular-weight residues inside the microgrooves are desorbed and discharged. The vacuum environment can significantly improve the desorption efficiency and prevent oxidation reactions, thereby achieving a clean, dry, and thermally stable surface in the interface locking zone. This completes the surface pretreatment. By first pre-drying the aluminum alloy insert with the mask layer removed using medium-low temperature circulating hot air, and then performing deep drying treatment in a medium-high temperature vacuum environment, the moisture, solvent residues, and volatile small molecules adsorbed on the roughened interface locking zone surface and inside the microgrooves can be gradually removed. This transforms the interface locking zone surface from a wet state to a dry and stable state, thereby reducing the risk of gas evolution and interface instability during subsequent injection molding.

[0055] S2. The pretreated aluminum alloy insert is fixed in the cavity of the injection mold. A first preset gap and a second preset gap are formed between the injection mold and the aluminum alloy insert. The engineering plastic melt is injected into the cavity of the injection mold, so that the engineering plastic melt is combined with the interface locking area of ​​the pretreated aluminum alloy insert. Excess engineering plastic melt enters the first preset gap and flows out from the through hole to the second preset gap, thus obtaining an integrated injection molded part.

[0056] In this embodiment, as a preferred option, S2 specifically includes:

[0057] S21. Fix the pre-treated aluminum alloy insert at the positions corresponding to the first and second preset gaps within the cavity of the injection mold. Close and lock the injection mold. The first and second preset gaps are formed between the pre-treated aluminum alloy insert and the cavity of the injection mold. Both the first and second preset gaps are connected to the through holes. By precisely positioning the aluminum alloy insert in the mold-closed state, the surface of the aluminum alloy insert relative to the marking area forms preset gaps with the upper and lower molds (or different mold surfaces) of the injection mold. The first and second preset gaps refer to the thin, dimensionally controlled spaces jointly defined by the mold cavity wall and the surface of the aluminum alloy insert. They do not directly bear the main molding volume but are used to accommodate excess melt during flow. This is achieved by making the through holes open. The first and second preset gaps are connected, allowing the melt entering the marking area through the first preset gap to continue flowing to the second preset gap through the through hole, thus forming a continuous, closed, and controllable melt transfer channel. By fixing the pretreated aluminum alloy insert into the injection mold cavity and forming independent and interconnected first and second preset gaps between the aluminum alloy insert and the injection mold at corresponding positions in the marking area, the through hole is simultaneously connected to the first and second preset gaps. This structurally constructs a melt flow path from the interface locking area through the first preset gap to the marking area, and then extending to the second preset gap through the through hole. This facilitates the orderly filling of engineering plastic melt and the controlled transfer of excess engineering plastic melt during the injection molding process.

[0058] S22. The engineering plastic is heated and plasticized to form an engineering plastic melt. The engineering plastic melt is injected into the cavity of the injection mold according to preset parameters. After entering the cavity, the engineering plastic melt flows preferentially to the interface locking area of ​​the pretreated aluminum alloy insert. After the engineering plastic melt fills the interface locking area to form an initial bonding interface, the excess engineering plastic melt flows directionally into the first preset gap and flows out through the through hole to the second preset gap. The preset parameters include injection speed and injection pressure.

[0059] In this embodiment, as a preferred option, S22 specifically includes:

[0060] S221. Engineering plastic is heated and plasticized to form an engineering plastic melt. The engineering plastic melt is injected into the cavity of the injection mold at an injection speed of 20-60 mm / s and an injection pressure of 30-80 MPa. After entering the cavity, the engineering plastic melt preferentially flows to the interface locking zone of the pretreated aluminum alloy insert. After the engineering plastic is heated to a plasticized state, it is injected into the cavity at an injection speed of 20-60 mm / s and an injection pressure of 30-80 MPa. These parameters are in the low-speed, medium-pressure injection range, which can effectively suppress the jet flow at the melt front. Because the interface locking zone is connected to the main cavity space and the flow resistance is small... Under pressure, the engineering plastic melt preferentially enters the interface locking zone and spreads along the aluminum alloy surface, thereby ensuring full contact between the melt and the roughened interface locking zone, instead of directly entering the first preset gap or through hole. By injecting the engineering plastic melt into the injection mold cavity at a low injection speed and medium injection pressure, the engineering plastic melt preferentially spreads and fills the interface locking zone of the pretreated aluminum alloy insert in the early stage of entering the cavity, thereby avoiding premature high-speed flow of the melt in the first preset gap. This is conducive to forming a stable and uniform melt coverage state in the interface locking zone, creating conditions for the subsequent establishment of a reliable initial bonding interface.

[0061] S222. Engineering plastic melt continuously fills the interface locking zone, forming a continuous melt cover layer and obtaining an initial bonding interface. Under continuous injection conditions, the engineering plastic melt entering the interface locking zone continuously replenishes and spreads, gradually filling the space within the interface locking zone and covering the roughened microgroove structure. When a continuous melt layer is formed on the surface of the interface locking zone, a preliminary physical bonding relationship is established between the engineering plastic melt and the aluminum alloy insert. At this state, the interface has not yet experienced significant overflow or transfer, and is mainly used to ensure the continuity of the interface area to withstand subsequent pressure changes. By continuously filling the interface locking zone with engineering plastic melt, a continuous and unbroken melt cover layer is formed on the surface of the interface locking zone, thereby establishing a stable initial bonding interface. This initial bonding interface provides a bearing foundation for the subsequent pressurization and directional flow of the engineering plastic melt, which is beneficial for maintaining the integrity and pressure state of the melt within the interface locking zone in subsequent stages.

[0062] S223. After obtaining the initial bonding interface, adjust the engineering plastic melt to continue injecting into the cavity of the injection mold at an injection speed of 60-150 mm / s and an injection pressure of 80-140 MPa. This pushes the excess engineering plastic melt from the interface locking zone towards the first preset gap, allowing it to enter the first preset gap. Increasing the injection speed to 60-150 mm / s and the injection pressure to 80-140 MPa raises the overall pressure level within the cavity. Since the interface locking zone is now covered by the melt, its flow resistance increases relatively, and the excess engineering plastic melt is further reduced under pressure. Under the action of the gradient, the melt flows along the path of less resistance in the direction of the marked area and enters the first preset gap. It preferentially enters the first preset gap, a low-resistance space, realizing the directional transfer of the engineering plastic melt between different areas, rather than disorderly diffusion. After the initial bonding interface is formed, by increasing the injection speed and injection pressure, the engineering plastic melt is made to maintain the coverage state in the interface locking area, while pushing the excess engineering plastic melt from the interface locking area to the marked area in a directional flow and into the first preset gap, thereby realizing the diversion and transfer of melt volume and avoiding excessive accumulation of melt in the interface locking area due to continuous filling.

[0063] S224. The engineering plastic melt entering the first preset gap further flows and enters the through hole. After the engineering plastic melt enters the through hole, the injection speed of the engineering plastic melt is restored to 20-60 mm / s, and the injection pressure is restored to 30-80 MPa, so that the engineering plastic melt in the interface locking zone is kept under pressure. Excess engineering plastic melt flows out through the through hole to the second preset gap. When the engineering plastic melt enters the through hole through the first preset gap, the through hole serves as a channel connecting the first and second preset gaps, allowing the engineering plastic melt to continue to transfer to the second preset gap. At this time, by restoring the injection speed to 20-60 mm / s and the injection pressure to 30-80 MPa, the instantaneous flow rate in the cavity can be reduced. Pressure fluctuations cause the engineering plastic melt in the interface locking zone to mainly bear stable static pressure, which is used to maintain the adhesion between the engineering plastic melt and the aluminum alloy interface. Excess engineering plastic melt is transferred along a predetermined channel under pressure, thereby achieving controlled overflow and pressure balance. By reducing the injection speed and injection pressure after the engineering plastic melt enters the through hole, the engineering plastic melt in the interface locking zone is kept under stable pressure. At the same time, excess engineering plastic melt is allowed to continue to flow out through the first preset gap and the through hole and enter the second preset gap. This ensures the tightness of the interface locking zone while preventing the engineering plastic melt in the marking area and through hole in the first preset gap from deforming or developing defects due to continuous high pressure.

[0064] In this embodiment, as a preferred solution, S23, by maintaining stable injection parameters during the injection molding process, the engineering plastic melt in the interface locking zone is kept under continuous pressure, resulting in an integrated injection molded part with stable flow. Stable injection parameters mean that after the phased injection and transfer of the engineering plastic melt are completed, the injection speed and injection pressure are kept within a preset range without significant increase or decrease, so that the pressure field in the cavity is in a relatively balanced state. At this time, the engineering plastic melt in the interface locking zone mainly bears stable static pressure, rather than rapidly changing dynamic pressure. This static pressure can continuously push the engineering plastic melt to fill and compact the microgroove structure on the surface of the roughened interface locking zone, while not causing the engineering plastic melt to flow on a large scale again. Since the excess engineering plastic melt has been transferred through the first preset gap and through hole, the engineering plastic melt in the interface locking zone is not prone to backflow or interface disturbance under stable parameter conditions, thereby achieving overall flow stabilization.

[0065] S3. Cool the integrated injection molded part. The engineering plastic melt entering the through hole and the first preset gap is formed into a light-transmitting thin-walled area. After cooling, demold to obtain the integrated injection molded part.

[0066] In this embodiment, as a preferred option, S3 specifically includes:

[0067] S31. Keep the injection mold in a closed, locked state to maintain the shape of the integrated injection molded part;

[0068] During the injection molding process, the engineering plastic melt is still in the transition stage from a high viscoelastic state to a solid state before cooling and solidification. At this time, there is a temperature gradient and shrinkage tendency inside the melt. By keeping the injection mold closed and locked, the cavity wall forms a rigid boundary constraint on the integrated injection molded part, which restricts the free deformation of the engineering plastic melt during the shrinkage process, so that it can only shrink in a controlled manner along the direction and size defined by the cavity, thereby avoiding irreversible geometric deviations before demolding.

[0069] By keeping the injection mold in a closed and locked state during the cooling stage, the integrated injection molded part is always subject to the geometric constraints of the cavity during the cooling process, thereby preventing the engineering plastic melt from deforming, warping, or displacing due to the release of internal stress before it has fully solidified. This step ensures that the interface locking area and the light-transmitting thin-walled area maintain their predetermined spatial position relationship in the early stage of cooling, which is beneficial to maintaining the interface bonding state and overall structural integrity formed during the injection stage.

[0070] S32. The cavity is cooled to 40-60°C by the cooling system of the injection mold, so that the engineering plastic melt entering the through hole and the first preset gap solidifies to form a light-transmitting thin-walled area, wherein the thickness of the light-transmitting thin-walled area is 0.3-1.2 mm.

[0071] The cooling system of the injection mold typically includes cooling water channels or cooling medium circulation channels located inside the mold. Cooling medium is introduced into these channels to remove heat from the cavity. When the cavity temperature drops to 40–60°C, the molecular chain mobility of the engineering plastic melt decreases significantly, the material viscosity increases rapidly, and solidification is completed. For thin-walled areas with small thicknesses, due to their low heat capacity and short heat dissipation paths, uniform solidification can be achieved within this temperature range, thus avoiding problems such as localized uncured areas or uneven cooling.

[0072] The injection mold cooling system controls the cavity temperature to 40-60°C, allowing the engineering plastic melt entering the through hole and the first preset gap to gradually transform from a molten state to a solid state. Under this controlled cooling condition, it is molded into a light-transmitting thin-walled area with a thickness of 0.3-1.2 mm. Specifically, the local thickness of the light-transmitting thin-walled area located in the region corresponding to the first preset gap and not coinciding with the through hole is relatively small (e.g., the thickness along the second direction is 0.3 mm), while the local thickness of the light-transmitting thin-walled area located in the region where the first preset gap coincides with the through hole is relatively large (e.g., the total thickness of the light-transmitting thin-walled area formed by the overlapping part of the first preset gap and the through hole along the second direction (the thickness of the first preset gap and the through hole) is 1.2 mm). This ensures that the light-transmitting thin-walled area is fully solidified while avoiding internal stress concentration caused by excessively rapid cooling, thereby improving the structural stability and molding consistency of the light-transmitting thin-walled area.

[0073] S33. After cooling is complete, open the injection mold and demold the integrated injection molded part from the cavity to obtain the integrated injection molded part;

[0074] After the engineering plastic melt has cooled and solidified in the cavity, its mechanical properties have changed from a viscoelastic state to a stable solid structure. At this time, the material has sufficient strength to withstand the mechanical forces generated during the demolding process. By opening the injection mold, the cavity constraints are released. Under the action of the demolding mechanism or manual removal, the integrated injection molded part is separated from the mold surface along the predetermined demolding direction, thereby completing the removal process of the molded part.

[0075] After confirming that the integrated injection molded part has cooled and solidified, the injection mold is opened and demolded, so that the molded aluminum alloy and plastic integrated structure is removed from the cavity, thereby obtaining a final integrated injection molded part with stable dimensions and reliable interface bonding. This avoids the problem of thin-walled area damage or interface peeling caused by forcibly demolding before the material has fully solidified.

[0076] During the injection molding process, when the engineering plastic melt enters the first preset gap from the interface locking zone and flows to the second preset gap through the through hole, the second preset gap is a semi-closed or closed space because it is not directly connected to the outside. The air inside cannot be quickly discharged. As the engineering plastic melt continues to enter, the volume of the air is compressed. According to the law of gas pressure, the pressure increases as the volume decreases, thus forming a gas pressure in the second preset gap acting towards the through hole. This gas pressure acts on the engineering plastic melt passing through the through hole, causing the melt to be compressed in the opposite direction at the outlet of the through hole, changing from a flowing state to a restricted compaction state, reducing the expansion space of the gas entrained in the melt. When the injection parameters remain stable, the reverse pressure generated by the gas compression works together with the injection pressure provided by the injection molding machine to make the engineering plastic melt in the interface locking zone and thin-walled molding area achieve higher solidification, without causing bulging or interface disturbance due to sudden pressure changes.

[0077] When the engineering plastic melt flows from the first preset gap into the second preset gap through the through hole, the second preset gap, as a relatively closed containment space, gradually compresses the original gas inside as the engineering plastic melt continues to enter, thus forming a certain gas back pressure within the second preset gap. This gas back pressure exerts a reverse squeezing effect on the flowing engineering plastic melt through the through hole, causing the melt to change from a free-flowing state to a restricted compacted state at the through hole outlet and adjacent thin-walled areas. This helps to reduce micropores and voids inside the engineering plastic melt, and improve the density and structural integrity of the engineering plastic melt in the light-transmitting thin-walled area. At the same time, this reverse gas pressure plays a buffering and stabilizing role on the melt in the interface locking zone direction, allowing the engineering plastic melt in the interface locking zone to maintain continuous pressure under stable injection parameters. This helps the integrated injection molded part obtain more uniform pressure transmission and a more stable molding state during the injection molding stage.

[0078] The air entering the second preset gap is relatively lighter than the engineering plastic melt, so it tends to rise. It can be slowly released through the micro-slits of the injection mold parting surface or the mold mating gap in the cavity. At the same time, when venting is required, the air can also be discharged through the vacuum port connected to the cavity. Specifically, the vacuum port is not normally open, but can be closed in a controllable manner. That is, when venting is not required, the second preset gap is in a relatively closed state.

[0079] Please see Figures 1 to 5The present invention also provides an integrated injection mold of aluminum alloy and plastic, characterized in that: the integrated injection molding method of aluminum alloy and plastic as described above is adopted, including an upper injection mold 10 and a lower injection mold 20 arranged sequentially along a first direction, the end face of the upper injection mold 10 abutting against the end face of the lower injection mold 20, a cavity 30 is formed between the upper injection mold 10 and the lower injection mold 20, the cavity 30 is used to place an aluminum alloy insert 40, and the lower injection mold 20 is provided with a positioning groove 21 that cooperates with the aluminum alloy insert 40.

[0080] The upper injection mold 10 includes an injection port 11, an upper mold body 12, a filling module 13, and a vacuum port 14. The filling module 13 is fixedly connected to the surface of the upper mold body 12 facing the lower injection mold 20 and is located within the cavity 30. The injection port 11 is opened on the surface of the upper mold body 12 away from the lower injection mold 20 and extends along a first direction through the filling module 13, communicating with the cavity 30. The vacuum port 14 is opened on the surface of the upper mold body 12 away from the lower injection mold 20 and communicates with the cavity 30. The filling module 13 is connected to the aluminum alloy insert. A first preset gap 51 is formed between the components 40 along the second direction. The injection mold 20 includes a lower mold body 22, and a positioning groove 21 is formed on the lower mold body 22. A second preset gap 52 is formed between the injection mold 20 and the aluminum alloy insert 40 along the second direction. The surface of the aluminum alloy insert 40 facing the filling module 13 is provided with an interface locking area 42 and an identification area 43. The surface of the aluminum alloy insert 40 is provided with a through hole 41 in the identification area 43 for communicating between the first preset gap 51 and the second preset gap 52.

[0081] The first and second directions are not just one orientation; that is, when the first or second direction is north-south, facing south or north is the first direction.

[0082] Both the upper injection mold 10 and the lower injection mold 20 are equipped with cooling systems, which can be heat exchange pipes with coolant flowing inside. This is existing known technology and will not be described in detail here.

[0083] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for integral injection molding of aluminum alloy and plastic, characterized in that, include: S1. Provide an aluminum alloy insert, wherein the aluminum alloy insert is provided with a marking area and an interface locking area that do not overlap and are not at the same horizontal height, at least one through hole is opened in the marking area to penetrate the aluminum alloy insert, and the interface locking area is surface pretreated to obtain a pretreated aluminum alloy insert. S1 specifically includes: S13. On the aluminum alloy insert with completed through holes, a corrosion-resistant mask layer is applied to the surface outside the interface locking area to isolate the marking area and other areas that are not pretreated. The interface locking area is degreased and cleaned before etching to form a microgroove structure for the wetting and mechanical interlocking of engineering plastic melt. After etching, the interface locking area is neutralized, rinsed and dried to obtain a roughened interface locking area. S14. On the aluminum alloy insert with a roughened interface locking region, the mask layer covering the interface locking region is removed, and the aluminum alloy insert is dried and activated. S2. The pretreated aluminum alloy insert is fixed in the cavity of the injection mold. A first preset gap and a second preset gap are formed on opposite sides of the marking area between the injection mold and the aluminum alloy insert. Both the first preset gap and the second preset gap are connected to the through hole. The engineering plastic melt is injected into the cavity of the injection mold, so that the engineering plastic melt combines with the interface locking area of ​​the pretreated aluminum alloy insert. Excess engineering plastic melt enters the first preset gap and flows out from the through hole to the second preset gap, resulting in an integrated injection molded part. S2 specifically includes: S22. The engineering plastic is heated and plasticized to form an engineering plastic melt. The engineering plastic melt is injected into the cavity of the injection mold according to preset parameters. After entering the cavity, the engineering plastic melt flows preferentially to the interface locking area of ​​the pretreated aluminum alloy insert. After the engineering plastic melt fills the interface locking area to form an initial bonding interface, the excess engineering plastic melt flows directionally into the first preset gap and flows out through the through hole to the second preset gap. The preset parameters include injection speed and injection pressure. S22 specifically includes: S221. The engineering plastic is heated and plasticized to form an engineering plastic melt. The engineering plastic melt is injected into the cavity of the injection mold at an injection speed of 20-60 mm / s and an injection pressure of 30-80 MPa. After entering the cavity, the engineering plastic melt preferentially flows to the interface locking area of ​​the pretreated aluminum alloy insert. S222: The engineering plastic melt continuously fills the interface locking zone, forming a continuous melt cover layer in the interface locking zone, thus obtaining the initial bonding interface. S223. After obtaining the initial bonding interface, the engineering plastic melt is adjusted to continue to be injected into the cavity of the injection mold at an injection speed of 60-150 mm / s and an injection pressure of 80-140 MPa, pushing the excess engineering plastic melt from the interface locking area to flow in a directional direction towards the first preset gap, so that the excess engineering plastic melt enters the first preset gap. S224. The engineering plastic melt that enters the first preset gap flows further and enters the through hole. After the engineering plastic melt enters the through hole, the injection speed of the engineering plastic melt is restored to 20-60 mm / s and the injection pressure is 30-80 MPa, so that the engineering plastic melt in the interface locking zone is kept under pressure. The excess engineering plastic melt flows out through the through hole to the second preset gap. S3. Cool the integrated injection molded part. The engineering plastic melt entering the through hole and the first preset gap is formed into a light-transmitting thin-walled area. After cooling, demold to obtain the integrated injection molded part. The second preset gap is a semi-closed or closed receiving space. The engineering plastic melt entering the second preset gap compresses the gas in the second preset gap, so that a gas back pressure is formed in the second preset gap acting in the direction of the through hole. The gas back pressure squeezes the engineering plastic melt at the outlet of the through hole in the opposite direction.

2. The integrated injection molding method for aluminum alloy and plastic according to claim 1, characterized in that, S1 specifically also includes: S11. Provide aluminum alloy inserts, and divide the aluminum alloy inserts into marking areas and interface locking areas that do not overlap and are not at the same horizontal height. S12. Perform through-processing in the marking area of ​​the aluminum alloy insert to form at least one through hole through the aluminum alloy insert, and deburr and round the corners of the hole wall to obtain an aluminum alloy insert with a completed through hole.

3. The integrated injection molding method for aluminum alloy and plastic according to claim 2, characterized in that: S14 specifically includes: S141. The mask layer covering the interface locking area includes one of tape or a continuous elastic film formed after coating with natural rubber. The aluminum alloy insert with the roughened interface locking area is heated at a temperature of 40-60°C for 1-3 minutes, and then the mask layer is peeled off along the boundary direction of the interface locking area at a peeling speed of 10-50 mm / s to obtain the aluminum alloy insert with the mask layer peeled off. S142. The aluminum alloy insert after the mask layer has been peeled off is pre-dried in circulating hot air at 40-70℃ for 10-30 minutes to obtain a pre-dried aluminum alloy insert. The pre-dried aluminum alloy insert is then treated in a vacuum oven at 70-120℃ for 20-90 minutes to complete the drying and activation treatment, and a pre-treated aluminum alloy insert is obtained.

4. The integrated injection molding method for aluminum alloy and plastic according to claim 2, characterized in that: In step S13, the etching solution used during etching includes an alkaline etching solution, which includes sodium hydroxide, sodium carbonate, and a wetting agent. The wetting agent includes at least one of lauryl alcohol polyoxyethylene ether, cetyl alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.

5. The integrated injection molding method for aluminum alloy and plastic according to claim 1, characterized in that, S2 also includes: S21. Fix the pretreated aluminum alloy insert at the position corresponding to the first and second preset gaps in the cavity of the injection mold, close and lock the injection mold, and form the first and second preset gaps between the pretreated aluminum alloy insert and the cavity of the injection mold. Both the first and second preset gaps are connected to the through hole. S23. By keeping the injection parameters stable during the injection process, the engineering plastic melt in the interface locking zone is kept under continuous pressure, and an integrated injection molded part with stable flow state is obtained.

6. The integrated injection molding method for aluminum alloy and plastic according to claim 1, characterized in that, S3 specifically includes: S31. Keep the injection mold in a closed, locked state to maintain the shape of the integrated injection molded part; S32. The cavity is cooled to 40-60°C by the cooling system of the injection mold, so that the engineering plastic melt entering the through hole and the first preset gap is solidified to form a light-transmitting thin-walled area. S33. After cooling is complete, open the injection mold and remove the integrated injection molded part from the cavity to obtain the integrated injection molded part.

7. An integrated injection mold of aluminum alloy and plastic, characterized in that: The integrated injection molding method for aluminum alloy and plastic as described in any one of claims 1-6 includes an upper injection mold (10) and a lower injection mold (20) arranged sequentially along a first direction. The end face of the upper injection mold (10) abuts against the end face of the lower injection mold (20). A cavity (30) is formed between the upper injection mold (10) and the lower injection mold (20). The cavity (30) is used to place an aluminum alloy insert (40). The lower injection mold (20) has a positioning groove (21) that mates with the aluminum alloy insert (40).

8. The integrated injection mold of aluminum alloy and plastic according to claim 7, characterized in that: The upper injection mold (10) includes an injection port (11), an upper mold body (12), a filling module (13), and a vacuum port (14). The filling module (13) is fixedly connected to the surface of the upper mold body (12) facing the lower injection mold (20) and is located inside the cavity (30). The injection port (11) is opened on the surface of the upper mold body (12) away from the lower injection mold (20) and extends along a first direction through the filling module (13) to communicate with the cavity (30). The vacuum port (14) 14) The upper mold body (12) is opened on the surface away from the lower injection mold (20) and communicates with the cavity (30). The filling module (13) and the aluminum alloy insert (40) form a first preset gap (51) along the second direction. The lower injection mold (20) includes a lower mold body (22). The positioning groove (21) is opened on the lower mold body (22). The lower injection mold (20) and the aluminum alloy insert (40) form a second preset gap (52) along the second direction.

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