Pressure equalization and shaping reinforcement process for aluminum profile molds

Abstract

This invention relates to the field of aluminum profile forming technology, and more specifically, to a process for equalizing pressure and enhancing the shape of aluminum profile molds. The process includes the following steps: S1, aluminum rod preheating, where the aluminum rod undergoes a three-stage preheating process with progressively increasing temperatures; S2, extrusion forming, where the aluminum rod is placed into an extruder and extruded into an aluminum profile mold, undergoing initial and stable extrusion stages. The stable stage increases the pushing speed and heating temperature of the aluminum rod compared to the initial stage; and S3, cooling, where the extruded material undergoes a three-stage cooling process, including front-stage air cooling, mid-stage pulsed water mist cooling, and rear-stage natural cooling combined with auxiliary air cooling. In S2, the aluminum profile mold includes an upper mold and a lower mold. The upper mold includes a feed inlet, which is recessed by 7mm and rounded. This invention enables more even pressure distribution within the aluminum profile mold and ultimately improves the product's shaping effect.

Description

Technical Field

[0001] This invention relates to the field of aluminum profile forming technology, and in particular to the process of pressure equalization and shaping reinforcement of aluminum profile molds. Background Technology

[0002] Aluminum profiles, as an important industrial material, are manufactured through processes including casting, extrusion molding, heat treatment, and surface treatment. Extrusion molding is the core process, where high pressure is applied to heated aluminum rods using a die to plastically deform them into the desired cross-sectional shape. This process is widely used in construction, transportation, and electronics. The efficiency and product quality of this process are highly dependent on parameters such as die design, extrusion speed, and temperature control. The rationality of the die structure is particularly critical, directly affecting the dimensional accuracy, surface quality, and energy consumption of the profiles.

[0003] Aluminum profile molds typically consist of an upper mold (distribution mold) and a lower mold (working zone mold). The upper mold distributes aluminum metal evenly into the mold cavity through distribution holes, while the lower mold shapes the final cross-section using the working zone. In traditional mold designs, due to issues such as a thicker upper mold, uneven internal structure of the aluminum rod, large pressure fluctuations during extrusion, and poor cooling of the aluminum profile after demolding leading to reverse heat conduction, heat tends to accumulate locally within the mold and is difficult to dissipate, resulting in temperature buildup. This localized temperature buildup within the aluminum profile mold not only causes internal pressure imbalance but also easily leads to thermal deformation and even cracking of the mold, ultimately affecting the final shaping effect of the profile. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, this application provides a pressure equalization and shaping reinforcement process for aluminum profile molds.

[0005] The aluminum profile mold pressure equalization and shaping reinforcement process provided by this invention adopts the following technical solution:

[0006] The pressure equalization and shaping reinforcement process for aluminum profile molds includes the following steps:

[0007] S1 aluminum rod preheating, the aluminum rod undergoes a three-stage preheating process and the temperature of the three stages increases sequentially;

[0008] S2 extrusion molding involves placing the pre-treated aluminum rod into an extruder and extruding it into an aluminum profile mold under the action of the extruder. The aluminum rod undergoes a two-stage extrusion process, including an initial stage and a stabilization stage. Compared to the initial stage, the stabilization stage increases the pushing speed and heating temperature of the aluminum rod.

[0009] S3 cooling involves a three-stage cooling process for the extruded material, including front-stage air cooling, mid-stage pulsed water mist cooling, and rear-stage natural cooling combined with auxiliary air cooling.

[0010] Preferably, in S2, the aluminum profile mold includes an upper mold and a lower mold. The upper mold includes a feed inlet, and the upper mold is recessed by 7mm and rounded at the feed inlet to form a recessed platform structure.

[0011] Preferably, the upper mold has a three-stage stepped structure, with the first stage having a depth of 3mm, the second stage having a depth of 2mm, and the third stage having a depth of 2mm, with a 15° gradient fillet between each stage.

[0012] Preferably, the aluminum rod is a 6063 aluminum alloy with a diameter of Φ150-200mm, and the extruded product is a harmonica tube with 9 parallel channels, a diameter of 23*23mm, a wall thickness of 1.8mm, and a continuous extrusion length of 6m.

[0013] Preferably, in S1, the preheating of the aluminum rod in three stages includes:

[0014] First stage: 380℃ x 20min, keep warm for 20±2min;

[0015] Second stage: 460℃ x 15min, heat preservation for 15±1min including 5min constant temperature plateau;

[0016] Third stage: 510℃ x 5 min, hold for 5 ± 0.5 min.

[0017] Preferably, in S2, the initial stage of pushing the aluminum rod is 0.6-1 mm / s. When the extrusion pressure reaches 80%-90% of the peak pressure, it enters the stabilization stage. In the stabilization stage, the temperature of the aluminum rod is increased to 515-525℃, and the extrusion speed is increased stepwise to 1-1.5 mm / s.

[0018] Preferably, in S3, the front section air cooling covers 0-2m of the extruded material, with a cooling rate of 25-35℃ / s, lasting for 18-22 seconds; the middle section water mist cooling covers 2-4m of the extruded material, is turned on for 3±0.5 seconds and then turned off for 2±0.5 seconds, with a cooling rate of 45-55℃ / s; the rear section cooling covers the area after 4m, with the auxiliary air cooling wind speed ≤5m / s.

[0019] Preferably, in S2, the extrusion pressure sensor monitors the pressure value in real time. When the pressure fluctuation exceeds ±5% of the set peak value, the temperature compensation mechanism is automatically triggered, and the heating rate is 2-3℃ / s.

[0020] Preferably, in S2, when the remaining length of the aluminum rod is 20-30% of the total length, the extrusion speed is reduced to 60-70% of the initial speed.

[0021] Preferably, in S3, the atomized water droplets of the water mist cooling have a particle size of 50-80 μm, and the air cooling airflow forms an angle of 30-45° with the axis of the extrudate.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. In S1, gradient temperature control pretreatment is used to solve the temperature accumulation caused by the uneven flow of the material. In S2, dynamic pressure compensation is used to solve the temperature accumulation caused by the external pressure fluctuation during the extrusion process. In S3, time-sequential zoned cooling is used to solve the indirect temperature accumulation caused by residual heat after molding. Finally, the three steps address the issues from the three dimensions of material uniformity, flow stability, and heat dissipation, respectively, so that the internal pressure of the aluminum profile mold is more balanced and the shaping effect of the product is ultimately improved.

[0024] 2. The upper die of the aluminum profile mold features a 7mm countersunk structure at the feed inlet with rounded corners to address the issue of its relatively thick thickness. This effectively reduces the breakthrough pressure during extrusion, thereby minimizing heat accumulation and enhancing the mold's stability during extrusion. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the top structure of the upper mold in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the bottom structure of the upper mold in an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the planar structure of the harmonica tube in an embodiment of this application.

[0028] Explanation of the attached diagram labels: 1. Upper mold; 2. Harmonica tube. Detailed Implementation

[0029] The following will combine Figures 1-3 The present invention will be further illustrated by the embodiments.

[0030] This embodiment discloses a pressure equalization and shaping enhancement process for aluminum profile molds. In this embodiment, a harmonica tube 2 with 9 parallel channels, a diameter of 23*23mm, a wall thickness of 1.8mm, and a continuous extrusion length of 6m is used as an example for illustration.

[0031] The pressure equalization and shaping reinforcement process for aluminum profile molds includes the following steps:

[0032] S1 aluminum rod preheating:

[0033] Preheating the aluminum rod improves its plasticity, facilitating subsequent extrusion flow. In this invention, the aluminum rod is a 6063 aluminum alloy with a diameter of Φ150-200mm. The aluminum rod undergoes three-stage preheating, including the first stage: 380℃ x 20min, holding for 20±2min to eliminate casting stress; the second stage: 460℃ x 15min, holding for 15±1min including a 5min isothermal plateau, for recrystallization and softening; and the third stage: 510℃ x 5min, holding for 5±0.5min, for the formation of a surface plastic layer. Compared to the single-stage preheating in traditional technology, which results in a high core surface temperature and insufficient core melting, leading to uneven internal structure and significant differences in core-to-surface flow velocity during subsequent extrusion, thus exacerbating pressure fluctuations, this invention effectively reduces the core-to-surface temperature difference to below 15℃ through three-stage preheating, resulting in a more uniform internal structure of the aluminum rod.

[0034] S2 extrusion molding:

[0035] The pretreated aluminum rod is placed into an extruder and extruded into an aluminum profile die under the action of the extruder. The extrusion process includes an initial stage and a stabilization stage. Initial stage: the rod is advanced at a low speed of 0.6-1 mm / s to establish a stable flow. Stabilization stage: when the extrusion pressure reaches 80%-90% of the peak pressure, the temperature of the aluminum rod is raised to 515-525℃, and the extrusion speed is increased in steps to 1-1.5 mm / s. The extrusion speed increase stage increases by 0.03-0.07 mm / s every 5-10 seconds, and the duration of the temperature increase stage does not exceed 15% of the total extrusion time of the aluminum rod. In traditional constant-speed extrusion, pressure fluctuations during the extrusion process can cause sudden changes in metal flow rate. Local flow rate differences can lead to turbulent flow and heat accumulation. Furthermore, the continuous rise in die temperature can cause high-temperature aluminum to adhere to the die surface, exacerbating flow resistance and heat accumulation. In this invention, by dynamically adjusting the speed and temperature, the temperature is increased when the pressure peak is high. This temperature increase compensates for the heat accumulation in the die, allowing the aluminum flowability to dynamically match the die temperature. This improves the aluminum flowability, reduces the probability of sticking to the die, and ultimately reduces the heat accumulation in the die, effectively addressing the problem of extrusion pressure fluctuations during the extrusion process.

[0036] S3 Cooling:

[0037] The cooling process of the extruded material is divided into three stages: front-stage, middle-stage, and rear-stage. The front-stage air cooling covers 0-2m of the extruded material, with a cooling rate of 25-35℃ / s and a duration of 18-22 seconds. The middle-stage water mist cooling covers 2-4m of the extruded material, using pulsed spraying, which is turned on for 3±0.5 seconds and off for 2±0.5 seconds, with a cooling rate of 45-55℃ / s. The rear-stage cooling covers the area after 4m, combining natural cooling with auxiliary air cooling at a wind speed of ≤5m / s. Based on the above cooling process, the front-stage air cooling can quickly remove heat from the surface of the extruded material, preventing heat from being conducted back to the mold and causing temperature accumulation in the mold. The middle-stage pulsed water mist cooling can avoid the sudden cooling stress caused by continuous cooling.

[0038] In summary, in S1, gradient temperature control pretreatment solves the problem of temperature accumulation caused by uneven internal material flow. In S2, dynamic pressure compensation solves the problem of temperature accumulation caused by external pressure fluctuations during the extrusion process. In S3, sequential zoned cooling solves the problem of indirect temperature accumulation caused by residual heat after molding. Ultimately, these three steps address the issues from the perspectives of material uniformity, flow stability, and heat dissipation, respectively, resulting in more balanced internal pressure in the aluminum profile mold and ultimately improving the product's shaping effect.

[0039] In S2, the extrusion pressure sensor monitors the pressure value in real time. When the pressure fluctuation exceeds ±5% of the set peak value, the temperature compensation mechanism is automatically triggered, with a heating rate of 2-3℃ / s, further improving the effect of dynamic pressure compensation.

[0040] In S2, when the remaining length of the aluminum rod is 20-30% of the total length, the extrusion speed is reduced to 60-70% of the initial speed to avoid metal flow instability caused by the reduction in the volume of the aluminum rod, prevent grain boundary cracks or uneven channel wall thickness caused by excessive shearing of the end material, and avoid the problem of increased scrap rate at the end that is common in traditional processes.

[0041] In S3, the atomized water droplets for water mist cooling have a particle size of 50-80μm, ensuring that the water droplets fully cover the pipe surface and vaporize rapidly, while avoiding quenching stress caused by excessively large water droplets or uneven cooling caused by excessively small water droplets. The air cooling airflow is at a 30-45° angle to the extrudate axis, which enhances the sweeping effect of the airflow on the pipe surface and avoids localized overcooling deformation caused by vertical airflow.

[0042] Reference Figures 1 to 3 In S2, the aluminum profile mold includes an upper mold 1 and a lower mold. The upper mold 1 includes a feed port. In particular, in this invention, the upper mold 1 has a total thickness of 71.5 mm and is recessed by 7 mm from the feed port with rounded corners to form a recessed platform structure. This addresses the issue of the upper mold 1 being relatively thick, effectively reducing the breakthrough pressure during extrusion, thereby reducing heat accumulation and enhancing the stability of the mold during extrusion.

[0043] In other embodiments, based on the 7mm recessed platform of the upper mold 1's inlet, a three-stage stepped recessed platform structure is further designed. The first stage recessed platform has a depth of 3mm, the second stage recessed platform has a depth of 2mm, and the third stage recessed platform has a depth of 2mm. A 15° gradual fillet is set between each stage. Through the graded pressure reduction design, the aluminum material flow forms a pressure gradient transition. The multi-stage stepped structure can change the direction of metal flow from a straight impact to a deflected buffer, reducing the temperature accumulation points caused by turbulence.

[0044] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A pressure equalization and shaping reinforcement process for aluminum profile molds, characterized in that, Includes the following steps: S1 aluminum rod preheating, the aluminum rod undergoes a three-stage preheating process and the temperature of the three stages increases sequentially; S2 extrusion molding involves placing the pre-treated aluminum rod into an extruder and extruding it into an aluminum profile mold under the action of the extruder. The aluminum rod undergoes a two-stage extrusion process, including an initial stage and a stabilization stage. Compared to the initial stage, the stabilization stage increases the pushing speed and heating temperature of the aluminum rod. S3 cooling involves a three-stage cooling process for the extruded material: initial air cooling, mid-stage pulsed water mist cooling, and final natural cooling combined with auxiliary air cooling. The aluminum rod is made of 6063 aluminum alloy with a diameter of Φ150-200mm, and the extruded product has 9 parallel channels with a diameter of 23mm. A harmonica tube (2) with a diameter of 23mm, a wall thickness of 1.8mm, and a continuous extrusion length of 6m; In S2, the initial stage of pushing the aluminum rod is 0.6-1mm / s. When the extrusion pressure reaches 80%-90% of the peak pressure, it enters the stabilization stage. In the stabilization stage, the temperature of the aluminum rod is raised to 515-525℃, and the extrusion speed is increased stepwise to 1-1.5mm / s.

2. The aluminum profile mold pressure equalization and shaping reinforcement process according to claim 1, characterized in that: In S2, the aluminum profile mold includes an upper mold (1) and a lower mold. The upper mold (1) includes a feed port. The upper mold (1) is recessed by 7mm and rounded at the feed port to form a recessed platform structure.

3. The aluminum profile mold pressure equalization and shaping reinforcement process according to claim 2, characterized in that: The upper mold (1) has a three-stage stepped sinking structure. The first stage sinking depth is 3mm, the second stage sinking depth is 2mm, and the third stage sinking depth is 2mm. A 15° gradient rounded corner is set between each stage.

4. The aluminum profile mold pressure equalization and shaping reinforcement process according to claim 1, characterized in that: In S3, the front section air cooling covers 0-2m of the extruded material, with a cooling rate of 25-35℃ / s, lasting for 18-22 seconds; the middle section water mist cooling covers 2-4m of the extruded material, turning on for 3±0.5 seconds and then turning off for 2±0.5 seconds, with a cooling rate of 45-55℃ / s; the rear section cooling covers the area after 4m, with an auxiliary air cooling wind speed ≤5m / s.

5. The aluminum profile mold pressure equalization and shaping reinforcement process according to claim 1, characterized in that: In S2, the extrusion pressure sensor monitors the pressure value in real time. When the pressure fluctuation exceeds ±5% of the set peak value, the temperature compensation mechanism is automatically triggered, and the heating rate is 2-3℃ / s.

6. The aluminum profile mold pressure equalization and shaping reinforcement process according to claim 4, characterized in that: In S3, the atomized water droplets of water mist cooling have a particle size of 50-80μm, and the air cooling airflow forms an angle of 30-45° with the axis of the extrudate.

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