Secondary bulging machining process for metal thin-wall container

Abstract

The invention discloses a secondary bulging machining process for a metal thin-wall container, efficient and high-precision forming of the metal thin-wall container is achieved through the synergistic effect of rapid combustion expansion of combustible gas and piston pressurization, and compared with a traditional hydraulic bulging technology, the secondary bulging machining process has the advantages that equipment is simplified, forming pressure is uniform and controllable, and a mold is flexible and adjustable. The multi-mold parallel connection and rapid circulation device is simple in structure, convenient to operate, particularly suitable for machining of complex special-shaped containers (such as containers with inclined walls, concave-convex textures and LOGO marks), through the multi-mold parallel connection and rapid circulation design, the production efficiency is improved by 30% or above, an additional demolding device is not needed, and the multi-mold parallel connection and rapid circulation device can be widely applied to the fields of food packaging, chemical containers, automobile parts and the like.

Description

Technical Field

[0001] The present invention relates to a secondary bulging processing technology for metal thin-walled containers, belonging to the technical field of metal thin-walled container processing. Background Art

[0002] In the prior art, the processing of metal thin-walled containers such as cups, cans, bottles, etc. usually adopts traditional processes such as stamping and stretching. These processes have many limitations in processing customized contents such as inclined walls, textures, logo texts, etc., and it is difficult to achieve precise processing of complex shapes, and the production efficiency is low.

[0003] In addition, although the traditional hydroforming and gas-liquid hybrid hydroforming technologies can improve the forming accuracy, they have the following problems: 1. Hydroforming requires complex hydraulic systems and high-pressure equipment, resulting in high costs.

[0004] 2. During the gas-liquid hybrid hydroforming process, the axial positioning of the tube blank is inaccurate, resulting in unreliable sealing and difficult workpiece taking after forming.

[0005] 3. In the prior art, the die design is complex and cannot be flexibly adjusted to meet the processing requirements of different shapes. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides a secondary bulging processing technology for metal thin-walled containers, which can achieve efficient and customized processing, and solves the problems of poor sealing, low production efficiency, complex die, etc. in the prior art.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a secondary bulging processing technology for metal thin-walled containers, including the following steps: The first step is to place the straight-wall blank into the lower die; The second step is that the bottom plate pushes the lower die to rise and cooperate with the sealed upper die to form a sealed space; The third step is that the nozzle on the piston sprays in a combustible gas mixture or oil mist; The fourth step is that the piston compresses the gas mixture in the sealed space downward, and the spark plug ignites, so that the internal gas burns and expands rapidly under high pressure to release heat, completing the bulging; The fifth step is that the bottom plate moves downward, the container is taken out, the piston returns to its original position, the bulged finished product is taken out, and the next cycle begins.

[0008] Furthermore, the sealed upper die is in interference fit with the straight-wall blank, and the periphery is pressed tightly by the inner wall of the sealed upper die in interference fit to ensure the sealing performance of the sealed space.

[0009] Furthermore, the nozzle can spray in a combustible gas mixture or oil mist, and can be adjusted according to the heat required by calculating the deformation temperature of the metal wall thickness.

[0010] Further, the lower die controls the outer shape of the product and does not participate in gas sealing, and can be changed into various combined dies to realize bulging into an irregular shape.

[0011] Further, the piston is internally provided with a spark plug and a nozzle, and its reciprocating movement speed is fast, and multiple dies can be connected in parallel to improve production efficiency.

[0012] Further, the piston supercharging can increase the pressure of the internal combustion gas, make the combustion complete instantly, generate sufficient pressure impact, act uniformly on the heated side wall, and avoid uneven deformation.

[0013] Further, during the bulging process, the inside of the die can be customized with slopes, shapes or logos, which are directly reflected on the product appearance after bulging.

[0014] Further, when the bottom plate pushes the lower die to rise, the compression spring moves upward until the limit height to ensure the tight fit between the straight-wall blank and the sealed upper die.

[0015] Further, after the bulging is completed, the atmospheric pressure inside the container causes the container to quickly pop out downward, without the need for an additional demolding device, which simplifies the process flow.

[0016] The beneficial effects of the present invention compared with the prior art are as follows: In the present invention, the inside of the die can be customized with slopes, shapes or logos, which are directly reflected on the product appearance after bulging. The nozzle can directly inject combustible mixed gas or oil mist, and the required heat can be calculated according to the metal wall thickness deformation temperature. The lower die controls the outer shape of the product and does not participate in gas sealing, and can be changed into various combined dies to realize bulging into an irregular shape. The piston is internally provided with a spark plug and a nozzle, with a fast reciprocating movement speed and a fast production rhythm, and multiple dies can be connected in parallel to improve production efficiency. The piston supercharging can increase the pressure of the internal combustion gas, make the combustion complete instantly, generate sufficient pressure impact, act uniformly on the heated side wall, and there will be no uneven deformation. Description of the Drawings

[0017] The following further describes the present invention with reference to the drawings.

[0018] Figure 1 It is a schematic structural diagram of the present invention. Detailed Embodiments

[0019] The following further elaborates the present invention with reference to specific embodiments.

[0020] As Figure 1 shown, a secondary bulging processing process for a thin-walled metal container of the present invention includes the following steps: The first step is to place the straight-wall blank into the lower die; In the second step, the bottom plate pushes the lower die upward. After it touches the sealing upper die, it continues to compress the spring and move upward until the limit height. At this time, the straight-wall blank is press-fitted into the sealing port in an interference fit, and the surrounding circle is tightly pressed by the inner wall of the sealing upper die in an interference fit. At this time, the combustion chamber of the combustion cylinder body and the inner cavity of the blank form a sealed space; the sealing upper die is in interference fit with the straight-wall blank, and the surrounding circle is tightly pressed by the inner wall of the sealing upper die in an interference fit to ensure the sealing performance of the sealed space.

[0021] In the third step, a combustible gas mixture or oil mist is sprayed into the nozzle on the piston; and it can be adjusted according to the required heat calculated from the deformation temperature of the metal wall thickness.

[0022] In the fourth step, the piston connecting rod drives the piston to compress the gas mixture in the sealed space downward. After reaching the position, the spark plug ignites. The internal gas burns and expands rapidly under high pressure, releasing heat, so that the straight-wall blank is formed by bulging; the piston is internally provided with a spark plug and a nozzle, and its reciprocating motion speed is fast. Multiple molds can be connected in parallel to improve production efficiency. The piston supercharging can increase the pressure of the internal combustion gas, make the combustion complete instantly, generate sufficient pressure impact, and act evenly on the heated side wall to avoid uneven deformation.

[0023] In the fifth step, the bottom plate moves downward, and the spring relaxes to make the sealing upper die disengage from the sealing port of the cylinder block. Without the pressing of the inner wall of the upper die, the clamping force of the container mouth on the cylinder block can no longer seal the gas with huge internal pressure. The atmospheric pressure inside the container will cause the container to quickly pop out downward. The formed container will move together with the lower die, and the internal air pressure is released at the same time. Then the piston moves upward to return to its position; the formed product is taken out from the lower die, and a straight-wall blank is put in to start the next cycle. The lower die controls the product shape and does not participate in gas sealing. It can be changed into various combined molds to realize bulging into irregular shapes. During the bulging process, the inside of the mold can be customized with slopes, shapes or logos, which will be directly reflected on the product appearance after bulging. When the bottom plate pushes the lower die upward, it compresses the spring and moves upward until the limit height to ensure the tight fit between the straight-wall blank and the sealing upper die.

[0024] In the present invention, the sealing upper die adopts a split structure, the gap between each petal module ≤ 0.02 mm, and dynamic sealing is realized through a hydraulic locking mechanism. During the bulging process, the metal surface temperature is monitored in real time by an infrared thermometer, and the injection amount of the gas mixture is dynamically adjusted, and the temperature control accuracy is ±10 °C. The split upper die in the present invention: consists of 12 tungsten steel modules, and the modules adopt a nanoscale gap fit (0.005 - 0.01 mm), and dynamic sealing is realized through a hydraulic locking mechanism, and deep cylindrical parts with a diameter / height ratio of up to 1:5 can be formed.

[0025] The lower die is a combined module with a quick switching function. For example: the lower die is equipped with a magnetic adsorption die base, and the die change can be completed within 30 s, and it supports the processing of special-shaped contours such as hexagons and bellows.

[0026] After the bulging is completed in the present invention, the atmospheric pressure inside the container causes the container to be quickly ejected downward, eliminating the need for an additional demolding device and simplifying the process flow. It is particularly suitable for forming complex-shaped containers made of materials such as austenitic stainless steel, aluminum alloy, and titanium alloy with a wall thickness of 0.2 to 3 mm.

[0027] Through the above process flow, efficient and customized secondary bulging processing of metal thin-walled containers can be achieved. In actual operation, process parameters such as the composition, injection amount of combustible gas or oil mist, compression degree of the piston, and ignition timing can be adjusted according to different metal materials, wall thicknesses, required shapes, etc. to achieve the best bulging effect.

[0028] The present invention utilizes the rapid combustion of high-pressure combustible gas in a sealed container to cause the internal air to rapidly heat up and expand, completing the bulging processing of metal thin-walled containers. Through piston pressurization and spark plug ignition, the rapid expansion of the combustion gas is realized to ensure uniform distribution of the bulging pressure. The internal slope, shape, or logo of the mold can be customized and directly reflected on the product appearance after bulging. The lower mold does not participate in gas sealing and can be changed to various combined molds to achieve the processing of irregular shapes. The piston is equipped with a spark plug and a nozzle, and the reciprocating movement speed is fast. Multiple molds can be connected in parallel to improve production efficiency.

[0029] Compared with the prior art, the present invention has the following advantages: 1. The mold design is flexible, enabling customized processing of complex shapes.

[0030] 2. High production efficiency, with a fast reciprocating movement speed of the piston, and multiple molds can be connected in parallel.

[0031] 3. The combustion bulging pressure is uniform, avoiding uneven deformation.

[0032] 4. There is no need for a complex hydraulic system, reducing equipment costs.

[0033] 5. After the bulging is completed, the atmospheric pressure inside the container causes the container to be quickly ejected, eliminating the need for an additional demolding device.

[0034] The process flow of the present invention is as follows: 1. Place the straight-wall blank in the lower mold.

[0035] 2. The bottom plate pushes the lower mold upward to cooperate with the sealed upper mold to form a sealed space.

[0036] 3. The nozzle on the piston injects a combustible gas mixture or oil mist.

[0037] 4. The piston compresses the gas mixture in the sealed space downward, and the spark plug ignites, causing the internal gas to rapidly burn and expand under high pressure, releasing heat and completing the bulging.

[0038] 5. The bottom plate moves downward, the container is removed, the piston returns to its original position, and the bulging formed product is taken out to start the next cycle.

[0039] The bulging of the present invention is realized by the rapid expansion of combustion gas. Compared with the traditional hydraulic or gas-liquid hybrid bulging technology, it has higher efficiency and lower cost. The combination of piston supercharging and spark plug ignition ensures uniform distribution of bulging pressure and solves the problem of uneven deformation in the prior art. The die design is flexible, enabling customized processing of complex shapes and having strong adaptability. The present invention first introduces the internal combustion engine combustion control principle into metal plastic processing, realizes superplastic deformation of materials through transient high pressure, breaks through the limitation of traditional static pressurization, combines the split die with the rapid die change system, and solves the contradiction between sealing and flexible forming in the processing of special-shaped parts. The multi-mode parallel and combustion instantaneous forming technology improves the production efficiency by more than 3 times compared with the prior art.

[0040] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A secondary bulging process for a metal thin-walled container, characterized in that: The following steps are involved: The first step is to place the straight-wall blank into the lower die; In the second step, the bottom plate pushes the lower die up and cooperates with the sealing upper die to form a closed space; In the third step, the nozzle on the piston sprays the combustible mixed gas or oil mist; In the fourth step, the piston compresses the mixed gas in the enclosed space downward, and the spark plug ignites, causing the internal gas to burn rapidly, expand and release heat under high pressure, completing the expansion; In the fifth step, the bottom plate moves downward, the container is ejected, the piston returns to its original position, the expanded product is taken out, and the next cycle begins.

2. A secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: The sealing upper die is interference fit with the straight wall blank, and a circle around it is pressed by the inner wall of the sealing upper die through interference fit, so as to ensure the sealing of the enclosed space.

3. A secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: The nozzle can spray combustible mixed gas or oil mist, and the required heat can be calculated and adjusted according to the deformation temperature of the metal wall thickness.

4. A secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: The lower mold controls the product shape and does not participate in gas sealing, and can be changed into various combined molds to achieve expansion into irregular shapes.

5. The secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: The piston has a built-in spark plug and a nozzle, has a fast reciprocating speed, and can be connected in parallel in multiple modes to improve production efficiency.

6. A secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: The piston pressurization can increase the pressure of the internal combustion gas, so that the combustion is completed instantly, and sufficient pressure impact is generated to evenly act on the heated side wall to avoid uneven deformation.

7. A secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: During the bulging process, the slope, shape or logo inside the mold can be customized, which will be directly reflected in the appearance of the product after bulging.

8. The secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: When the bottom plate pushes the lower die to rise, the compression spring moves upward to a limit height to ensure a close fit between the straight-wall blank and the sealed upper die.

9. A secondary bulging process for a metal thin-walled container according to claim 1, characterized in that: After the bulging is completed, the atmospheric pressure inside the container causes the container to be quickly ejected downward, without the need for an additional demoulding device, thus simplifying the process.

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