A beer bottle lightweight pressure blow molding method based on variable wall thickness control

Abstract

The application discloses a kind of based on variable wall thickness control's beer bottle lightweight pressure blow forming method, through material drop accurate supply, initial mould variable pressure pressing, bottle blank vacuum shaping, mould transfer preheating, three-stage variable pressure blow forming, partition cooling solidification, annealing stabilization, eight major steps of on-line detection, in combination with variable-diameter punch, partition temperature control, dynamic punch compensation, segmented vacuum control, realize the differentiation of beer bottle mouth, shoulder, body, bottom wall thickness Precision distribution;The weight of the 500ml specification beer bottle prepared is only 260-280g, the weight reduction is 15%-23%, the bottle body thickness ratio is less than or equal to 1.8:1, and the internal pressure strength is greater than or equal to 1.6MPa, the impact strength is greater than or equal to 1.0J, the internal stress is less than or equal to 2 levels, solve the contradiction between weight reduction and strength, at the same time reduce the defective rate to 2%-3%, save raw materials and energy consumption, adapt to the demand of beer bottle large-scale green production.

Description

Technical Field

[0001] This invention belongs to the field of glass container molding and manufacturing technology, and particularly relates to a lightweight pressure blow molding method for beer bottles based on variable wall thickness control. Background Technology

[0002] Beer bottles are the core container for beer packaging, and their molding process directly determines the product's weight, structural strength, appearance quality, and production economics. Currently, the mainstream molding process for beer bottles in the industry is the narrow-neck blow molding (NNPB). This process uses a two-step molding method of "forming a preform by pressing a primary mold and forming the bottle body by blowing a secondary mold," which improves the uniformity of glass melt distribution compared to the traditional blow molding method, making it the mainstream choice for large-scale production.

[0003] However, existing small-mouth blow molding and other beer bottle forming processes all suffer from a core technical problem that has not been effectively solved: the inability to achieve precise control over the wall thickness of different parts of the bottle. In traditional processes, after the glass droplet is pressed into a blank by a primary mold, it is transferred to a final mold for one-time high-pressure blow molding. During the blowing process, the glass melt is affected by multiple factors such as centrifugal force, mold cavity resistance, and temperature gradient. The flow and distribution of the glass material rely entirely on natural formation, and it is impossible to actively control and precisely distribute the wall thickness according to the stress characteristics of different parts of the bottle.

[0004] The existence of this core technical problem has made it impossible to simultaneously meet the dual requirements of lightweighting and structural strength in beer bottle production, becoming a key bottleneck restricting the green and lightweight development of beer bottles. If weight reduction is simply pursued by uniformly thinning the bottle body, the straight cylindrical part of the bottle body is prone to a significant decrease in impact resistance and internal pressure resistance due to excessively thin walls, failing to meet national standards. On the other hand, if excessive glass redundancy is retained to ensure strength, it will result in a large waste of raw materials and energy, which is inconsistent with the industry development trend of green production and cost reduction and efficiency improvement. In existing technologies, some solutions attempt to achieve lightweighting of beer bottles by adjusting mold capacity, optimizing the structure of the blow molding device, and improving glass formulations, but none of them address the core issue of "precise control of variable wall thickness." They still adopt a molding mode of uniform blowing and overall cooling, which cannot distribute the wall thickness according to the actual stress conditions of different parts of the bottle mouth, shoulder, body, and bottom. Ultimately, it still cannot solve the contradiction between lightweighting and strength, nor can it reduce molding defects such as cold lines, bubbles, and breakage caused by uneven wall thickness.

[0005] Therefore, it is necessary to develop a blow molding method that can achieve precise control of the wall thickness differences in different parts of a beer bottle, fundamentally solve the core technical defects of traditional processes, and achieve the molding goal of "reducing weight without reducing quality" for beer bottles. This has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the core technical problem that traditional beer bottle press-blow molding processes cannot achieve precise control over the wall thickness of different parts of the bottle. It provides a lightweight press-blow molding method for beer bottles based on variable wall thickness control. Through multi-step collaborative control and the integration of multiple specialized technologies, it achieves precise and differentiated distribution of wall thickness in the bottle's mouth, shoulder, body, and bottom, fundamentally solving the technical problem of the inability of traditional processes to precisely control variable wall thickness. Simultaneously, it provides lightweight beer bottles prepared using this method, achieving lightweight while maintaining structural strength and performance, reducing production defect rates and energy consumption, and adapting to the needs of large-scale green production.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A lightweight pressure blow molding method for beer bottles based on variable wall thickness control includes the following steps: Step S1, Precise Droplet Supply: The sodium-calcium-silicon glass melt droplet with a temperature of 1150-1200℃ and a weight of 270-290g is quantitatively cut by a droplet shear and then vertically dropped into the closed primary mold cavity. Step S2, initial mold pressure control: segmented pressure control is adopted. First, the punch is driven to press down for 3-5 seconds with a pressure of 0.4-0.5MPa to complete the initial shaping of the bottle mouth and preform. Then, the pressure is increased to 0.6-0.7MPa and held for 2-3 seconds to increase the density of the preform mouth and form a preset wall thickness gradient at the shoulder. Step S3, Preform Vacuum Shaping: While maintaining the pressure of the initial mold, the initial mold vacuum system is activated to draw out the gap between the preform and the mold cavity with a negative pressure of -0.04 to -0.06 MPa for 5-8 seconds, so that the outer surface of the preform is precisely attached to the inner wall of the initial mold, forming a gradient preform with a mouth wall thickness of 2.8-3.2 mm, a shoulder wall thickness of 2.2-2.5 mm, and a body wall thickness of 1.9-2.1 mm; Step S4, Preheating for Molding Transfer: The shaped preform is transferred to the molding cavity by rotating it 180° using a robotic arm. The transfer time is controlled at 1.5-2.0s. During the transfer process, the preform is preheated with infrared light to maintain the overall temperature of the preform at 950-1000℃ to avoid uneven temperature. Step S5, Three-stage variable pressure blow molding: Three stages of differentiated pressure airflow are sequentially introduced into the preform. The first stage is low-pressure pre-blowing: 0.15-0.20MPa airflow is blown for 1.0-1.5s to initially expand the preform to 80% of the mold cavity volume; the second stage is medium-pressure thickness control: 0.30-0.35MPa airflow is blown for 2.0-2.5s, combined with mold zone temperature control, to precisely control the wall thickness of the straight cylindrical part of the bottle; the third stage is high-pressure shaping: 0.50-0.60MPa airflow is held for 3.0-3.5s to make the bottle body completely fit the mold cavity and strengthen the wall thickness of the bottom and corner parts of the bottle. Step S6, Zoned Cooling and Curing: Activate the molded zoned cooling system. Use 25-30℃ cooling water for rapid cooling of the straight cylindrical part of the bottle body at a cooling rate of 80-100℃ / s, controlling the wall thickness to 1.6-1.8mm; use 45-50℃ cooling water for slow cooling of the bottle shoulder and bottom at a cooling rate of 30-40℃ / s, controlling the wall thickness to 2.3-2.6mm; the total cooling time is 6-8s, reducing the bottle temperature to 550-600℃. Step S7, Annealing Stabilization Treatment: The molded beer bottle is sent into an annealing furnace, heated to 560-580℃ at a rate of 5℃ / min and held for 10-15min, then cooled to 200℃ at a rate of 3℃ / min, and finally allowed to cool naturally to room temperature to eliminate internal stress. Step S8, online inspection and sorting: The uniformity of wall thickness and appearance defects are detected by a vision inspection system. Qualified products enter the next process, and unqualified products are crushed and recycled.

[0009] In a preferred embodiment of the present invention, in step S1, the components of the sodium-calcium-silicon glass melt by weight percentage are: SiO2 72-74%, Na2O 13-15%, CaO 8-10%, Al2O3 2-3%, MgO 1-2%, and clarifying agent 0.5-0.8%. The temperature deviation of the droplets is controlled within ±10℃, and the weight deviation of the droplets is controlled within ±5g.

[0010] In a preferred embodiment of the present invention, in step S2, the punch has a variable diameter structure, the diameter of the lower section of the punch matches the inner diameter of the beer bottle mouth, and the diameter of the upper section of the punch gradually decreases away from the lower section, forming a cone angle of 15°-20°; during the pressing process, the downward speed of the punch is controlled at 15-20mm / s, and the uniformity deviation of the gap between the punch and the initial mold cavity is ≤±0.1mm.

[0011] In a preferred embodiment of the present invention, in step S3, the initial mold vacuum system includes an annular vacuum groove on the inner wall of the initial mold, a vacuum pipeline, a negative pressure sensor, and a vacuum regulating valve. The annular vacuum groove is segmented along the bottle shoulder and bottle body direction of the preform. Each segment of the annular vacuum groove is connected to an independent vacuum regulating valve and a negative pressure sensor. The negative pressure of each segment is independently regulated, and the negative pressure deviation is ≤ ±0.01MPa.

[0012] In a preferred embodiment of the present invention, in step S4, infrared preheating is performed using an infrared radiation heating device with a heating power of 8-10kW. The heating area fully covers the outer surface of the preform, and the temperature uniformity deviation of each part of the preform is ≤±20℃. The transfer positioning accuracy of the robotic arm is ≤±0.2mm.

[0013] In a preferred embodiment of the present invention, in step S5, the three-stage variable pressure blowing adopts a nozzle structure with a coaxial dual airflow channel. The inner channel is filled with high-pressure forming gas, and the outer channel is filled with auxiliary temperature control gas. The temperature of the auxiliary temperature control gas is 400-500℃ and the flow rate is 5-8L / min, which prevents uneven glass crystallization caused by local rapid cooling during the preform blowing process. The forming gas is dry compressed air with a water content ≤50ppm.

[0014] In a preferred embodiment of the present invention, in step S5, during the three-stage variable pressure blow molding process, the punch is synchronously driven to perform dynamic compensation up and down. During the pre-blowing stage, the punch remains stationary. During the thickness control stage, the punch moves upward at a speed of 5-8 mm / s for 1.0-1.5 mm. During the shaping stage, the punch moves downward at a speed of 10-15 mm / s to return to its original position. By adjusting the forming space inside the preform through the dynamic movement of the punch, the wall thickness of each part is precisely controlled.

[0015] In a preferred embodiment of the present invention, in step S6, the mold-forming zoned cooling system includes a straight cylinder cooling chamber, a shoulder bottom cooling chamber, an independent cooling water circuit, a temperature sensor, and a flow regulating valve. A heat insulation layer is provided between the straight cylinder cooling chamber and the shoulder bottom cooling chamber for thermal isolation. The flow rate of the straight cylinder cooling water circuit is 15-20 L / min, and the flow rate of the shoulder bottom cooling water circuit is 8-12 L / min. The water temperature and flow rate of each circuit are controlled in real time by the temperature sensor and the flow regulating valve, with deviations of ≤±2℃ and ±1L / min, respectively.

[0016] In a preferred embodiment of the present invention, in step S8, the online detection adopts a detection system combining laser wall thickness detection and high-definition visual detection. The accuracy of laser wall thickness detection is ±0.05mm, and the resolution of high-definition visual detection is ≥20 million pixels. The detection speed of the detection system is ≥600 bottles / minute, and it can identify microcracks larger than 0.1mm, bubbles larger than 0.2mm in diameter, and appearance defects such as missing material and cold lines on the bottle surface.

[0017] A lightweight beer bottle based on variable wall thickness control is manufactured using the aforementioned lightweight beer bottle pressure blow molding method based on variable wall thickness control. The nominal volume of the beer bottle is 500ml, and the overall weight is 260-280g. The wall thickness distribution of various parts of the bottle is as follows: mouth size 2.8-3.2mm, shoulder size 2.3-2.6mm, straight section size 1.6-1.8mm, bottom size 2.4-2.7mm, and the ratio of the maximum wall thickness to the minimum wall thickness of the bottle is ≤1.8:1.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) It fundamentally solves the core technical problems of traditional processes: This invention achieves differentiated and precise control of the wall thickness of beer bottle mouth, shoulder, body and bottom by means of precise material drop supply, initial mold pressure pressing, vacuum shaping, three-stage pressure blowing and zoned cooling, combined with special technologies such as variable diameter punch, dynamic punch compensation, segmented vacuum control and zoned temperature control. The thickness ratio of the bottle body is reduced to below 1.8:1, which completely solves the core defect of traditional processes that cannot accurately control variable wall thickness, and provides core technical support for the lightweight development of beer bottles.

[0019] (2) Achieving a perfect balance between lightweight and structural strength: The 500ml beer bottle produced by this invention weighs only 260-280g, which is 15%-23% lighter than the traditional 330-350g beer bottle. At the same time, it ensures that the bottle body has an internal pressure resistance of ≥1.6MPa, an impact resistance of ≥1.0J, and an internal stress of ≤2. All performances are better than the requirements of the national standard GB / T4544-2020, achieving the molding goal of "reducing weight without reducing quality" and solving the core contradiction between lightweight and strength in the industry.

[0020] (3) Significantly improve molding quality and reduce defect rate: The vacuum forming technology of this invention eliminates the gap between the preform and the mold cavity, ensuring the accuracy of preform forming; zoned cooling and auxiliary temperature-controlled gas avoid local rapid cooling and crystallization of glass material, reducing defects such as cold lines and bubbles; the online detection system enables rapid sorting of defective products. Using the method of this invention, the defect rate of beer bottle production is reduced from 8%-12% in traditional processes to 2%-3%, and production stability and product quality are significantly improved.

[0021] (4) Energy saving and environmental protection, reducing production costs: The lightweight molding of this invention reduces the weight of beer bottles by 15%-23%, directly reducing glass raw material consumption by more than 20%; the reduction in raw material consumption also reduces the energy consumption of the furnace for melting glass by more than 18%, and the production cost per bottle is reduced by RMB 0.05-0.08. In addition, the crushing and recycling of unqualified products realizes the recycling of raw materials, further reducing raw material waste and adapting to the industry development trend of large-scale green production of beer bottles.

[0022] (5) Strong process compatibility and easy to scale up: The molding method of the present invention can be realized by modifying the existing small-mouth blow molding production equipment. There is no need to replace the entire production line. Only auxiliary equipment such as vacuum system, zoned cooling system, infrared preheating device, and dynamic punch drive device need to be added. The modification cost is low and the compatibility is strong, making it suitable for large-scale promotion and application by major beer bottle manufacturers in China. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments or prior art, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The flowchart illustrates a lightweight pressure blow molding method for beer bottles based on variable wall thickness control, as provided in this embodiment of the invention.

[0025] Figure 2 This is a schematic diagram of the initial mold pressure pressing and vacuum shaping provided in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of a three-stage variable pressure blow molding structure provided in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the molded partition cooling system provided in an embodiment of the present invention.

[0028] Figure 5 This is a schematic diagram of the structure of the variable diameter punch provided in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the wall thickness distribution of a lightweight beer bottle provided in an embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] To address the technical challenge of precise control over the wall thickness of different parts of the beer bottle in traditional pressure blow molding processes, this invention employs a synergistic control method involving quantitative material supply, staged variable pressure molding, vacuum molding, and zoned temperature-controlled cooling. This achieves precise and differentiated distribution of wall thickness across the bottle's mouth, shoulder, body, and bottom. Specifically, refer to... Figure 1 A lightweight pressure blow molding method for beer bottles based on variable wall thickness control includes the following steps: Step S1, Precise Droplet Feeding: A droplet of molten soda-lime silicate glass, measuring 1150-1200℃ and weighing 270-290g, is quantitatively cut using droplet shears and then vertically dropped into a closed initial mold cavity. The temperature and weight of the droplet in Step S1 are fundamental to ensuring precise control of the subsequent wall thickness. Within this temperature range, the molten soda-lime silicate glass exhibits good fluidity and formability, while the weight range provides precise glass material distribution space for the subsequent lightweight molding of 500ml beer bottles.

[0032] Step S2, Initial Mold Variable Pressure Pressing: Segmented pressure control is employed. First, a pressure of 0.4-0.5 MPa is used to drive the punch downwards for 3-5 seconds to initially shape the bottle neck and preform. Then, the pressure is increased to 0.6-0.7 MPa and held for 2-3 seconds to increase the density of the preform neck and create a preset wall thickness gradient at the shoulder. Segmented variable pressure pressing avoids the problems of loose neck forming and uneven glass material distribution at the shoulder caused by single-pressure pressing, laying the foundation for subsequent variable wall thickness forming.

[0033] Step S3, Preform Vacuum Shaping: While maintaining pressure in the initial mold, the initial mold vacuum system is activated, using a negative pressure of -0.04 to -0.06 MPa to suction the gap between the preform and the mold cavity, maintaining this pressure for 5-8 seconds. This ensures that the outer surface of the preform precisely conforms to the inner wall of the initial mold, forming a gradient preform with a mouth wall thickness of 2.8-3.2 mm, a shoulder wall thickness of 2.2-2.5 mm, and a body wall thickness of 1.9-2.1 mm. Vacuum suction eliminates the gap between the preform and the mold cavity, ensuring precise shaping of the preform's outer contour and wall thickness gradient, and preventing wall thickness deviations during subsequent blow molding.

[0034] Step S4, Preheating for Molding Transfer: The shaped preform is transferred to the molding cavity by rotating it 180° using a robotic arm. The transfer time is controlled within 1.5-2.0 seconds. During the transfer, the preform is preheated with infrared radiation to maintain the overall temperature of the preform at 950-1000℃, avoiding uneven temperature distribution. Temperature loss and localized temperature differences are prone to occur during preform transfer. Infrared preheating ensures uniform overall temperature of the preform, preventing uneven glass flow due to uneven temperature during subsequent blowing, which could lead to uneven wall thickness.

[0035] Step S5, Three-stage variable pressure blow molding: Three stages of differentiated pressure airflow are sequentially introduced into the preform. The first stage is low-pressure pre-blowing: 0.15-0.20 MPa airflow for 1.0-1.5 seconds, allowing the preform to initially expand to 80% of the mold cavity volume. The second stage is medium-pressure thickness control: 0.30-0.35 MPa airflow for 2.0-2.5 seconds, combined with mold zone temperature control, to precisely control the wall thickness of the straight cylindrical section of the bottle. The third stage is high-pressure shaping: 0.50-0.60 MPa airflow for 3.0-3.5 seconds, ensuring the bottle body completely fits the mold cavity and strengthening the wall thickness at the bottom and corners. Three-stage variable pressure blow molding can adjust the flow and distribution of glass material according to different stages of preform expansion, achieving precise control of the wall thickness in each part and avoiding localized overstretching or glass accumulation caused by one-time high-pressure blowing.

[0036] Step S6, Zoned Cooling and Curing: Activate the molded zoned cooling system. Rapidly cool the straight cylindrical section of the bottle body with 25-30℃ cooling water at a rate of 80-100℃ / s, controlling the wall thickness to 1.6-1.8mm. Slowly cool the bottle shoulder and bottom with 45-50℃ cooling water at a rate of 30-40℃ / s, controlling the wall thickness to 2.3-2.6mm. The total cooling time is 6-8 seconds, reducing the bottle temperature to 550-600℃. The straight cylindrical section of the bottle body experiences relatively uniform stress, allowing for rapid cooling to achieve thin-walled lightweight construction. The bottle shoulder and bottom are stress concentration areas; slow cooling ensures the density and strength of the glass material while maintaining the preset wall thickness distribution.

[0037] Step S7, Annealing Stabilization Treatment: The formed beer bottle is placed in an annealing furnace, heated to 560-580℃ at a rate of 5℃ / min and held for 10-15 minutes, then cooled to 200℃ at a rate of 3℃ / min, and finally allowed to cool naturally to room temperature to eliminate internal stress. Internal stress is easily generated during glass forming, making the product brittle. Stepped annealing can gradually eliminate internal stress, improving the structural stability and safety of the beer bottle.

[0038] Step S8, Online Inspection and Sorting: A vision inspection system is used to check the uniformity of wall thickness and appearance defects. Qualified products proceed to the next process, while unqualified products are crushed and recycled. Online inspection enables rapid sorting of defective products, ensuring product quality. At the same time, crushing and recycling allows for the recycling of glass raw materials, reducing material waste.

[0039] In step S1, the composition of the soda-lime-silica glass melt, by weight percentage, is: SiO2 72-74%, Na2O 13-15%, CaO 8-10%, Al2O3 2-3%, MgO 1-2%, and clarifying agent 0.5-0.8%. The temperature deviation of the droplets is controlled within ±10℃, and the weight deviation of the droplets is controlled within ±5g. Soda-lime-silica glass with this composition exhibits good formability, strength, and chemical stability, making it suitable for beer bottle applications. Precise control of the temperature and weight deviation of the droplets ensures accurate wall thickness control from the outset.

[0040] In step S2, the punch has a variable diameter structure. The diameter of the lower section of the punch matches the inner diameter of the beer bottle neck, and the diameter of the upper section of the punch gradually decreases away from the lower section, forming a cone angle of 15°-20°. During the pressing process, the downward speed of the punch is controlled at 15-20 mm / s, and the uniformity deviation of the gap between the punch and the initial mold cavity is ≤±0.1 mm. The cone angle design of the variable diameter punch matches the forming contour of the bottle neck and shoulder, which can guide the glass material to flow in the preset direction and form a wall thickness gradient at the shoulder. Precise control of the downward speed and gap of the punch can avoid excessive compression or stretching of the glass material, ensuring the accuracy of the wall thickness at the bottle neck and shoulder.

[0041] In step S3, the initial mold vacuum system includes an annular vacuum groove on the inner wall of the initial mold, vacuum pipelines, a negative pressure sensor, and a vacuum regulating valve. The annular vacuum groove is segmented along the bottle shoulder and body direction of the preform. Each segment of the annular vacuum groove is connected to an independent vacuum regulating valve and a negative pressure sensor. The negative pressure of each segment is independently adjustable, with a negative pressure deviation ≤ ±0.01MPa. The segmented vacuum groove and independent control system can adjust the negative pressure according to the molding requirements of different parts of the preform, ensuring that all parts of the preform can accurately fit the mold cavity, achieving precise molding of the preform with gradually varying wall thickness.

[0042] In step S4, infrared preheating uses an infrared radiation heating device with a heating power of 8-10kW. The heating area fully covers the outer surface of the preform, and the temperature uniformity deviation of each part of the preform is ≤±20℃. The transfer and positioning accuracy of the robotic arm is ≤±0.2mm. Full-coverage infrared preheating ensures uniform temperature of each part of the preform, avoiding differences in glass flow caused by temperature differences. High-precision robotic arm transfer ensures accurate positioning of the preform in the mold, preventing uneven wall thickness and molding defects caused by positioning deviations.

[0043] In step S5, the three-stage variable pressure blow molding employs a coaxial dual-airflow channel nozzle structure. The inner channel carries high-pressure forming gas, while the outer channel carries auxiliary temperature-controlled gas. The auxiliary temperature-controlled gas has a temperature of 400-500℃ and a flow rate of 5-8 L / min to prevent uneven glass crystallization caused by localized rapid cooling during preform inflation. The forming gas is dry compressed air with a moisture content ≤50 ppm. The coaxial dual-airflow channel can compensate for the temperature of the preform during inflation molding, preventing localized rapid cooling and crystallization of the glass material due to low mold cavity temperature, and ensuring good glass flow. The dry forming gas also prevents moisture from entering the bottle body, thus preventing defects such as bubbles and cold lines.

[0044] In step S5, during the three-stage variable pressure blowing process, the synchronously driven punch performs dynamic vertical compensation. During the pre-blowing stage, the punch remains stationary; during the thickness control stage, the punch moves upwards by 1.0-1.5 mm at a speed of 5-8 mm / s; and during the shaping stage, the punch moves downwards back to its original position at a speed of 10-15 mm / s. This dynamic movement of the punch adjusts the forming space inside the preform, precisely controlling the wall thickness of each part. The dynamic compensation of the punch actively adjusts the distribution space of the glass material inside the preform, working in conjunction with the three-stage variable pressure blowing process to achieve fine control of the wall thickness, especially in the straight cylindrical section of the bottle body and the corner of the bottle bottom.

[0045] In step S6, the mold-forming zoned cooling system includes a straight-cylinder cooling chamber, a shoulder-bottom cooling chamber, an independent cooling water circuit, a temperature sensor, and a flow regulating valve. A heat insulation layer is installed between the straight-cylinder cooling chamber and the shoulder-bottom cooling chamber for thermal isolation. The flow rate of the cooling water circuit in the straight-cylinder section is 15-20 L / min, and the flow rate of the cooling water circuit in the shoulder-bottom section is 8-12 L / min. The water temperature and flow rate of each circuit are controlled in real time by the temperature sensor and the flow regulating valve, with deviations of ≤±2℃ and ±1 L / min, respectively. The heat insulation layer prevents heat exchange between the straight-cylinder section and the shoulder-bottom section, ensuring the effectiveness of zoned cooling. The real-time controlled cooling water temperature and flow rate can precisely control the cooling rate of each part, fix the preset wall thickness distribution, and ensure the density of the glass.

[0046] In step S8, the online inspection employs a combined laser wall thickness detection and high-definition vision inspection system. The laser wall thickness detection accuracy is ±0.05mm, and the high-definition vision inspection resolution is ≥20 million pixels. The inspection system's inspection speed is ≥600 bottles / minute, and it can identify microcracks larger than 0.1mm, bubbles larger than 0.2mm in diameter, and surface defects such as missing material and cold lines on the bottle surface. Laser wall thickness detection enables precise detection of the wall thickness of various parts of the bottle, while high-definition vision inspection can quickly identify surface defects. The high inspection speed is suitable for the needs of large-scale production, enabling real-time control of product quality.

[0047] like Figure 6As shown, this invention also provides a lightweight beer bottle based on variable wall thickness control, which is manufactured using the aforementioned lightweight beer bottle pressure blow molding method based on variable wall thickness control. The nominal volume of the beer bottle is 500ml, and the overall weight is 260-280g. The wall thickness distribution of various parts of the bottle is as follows: mouth 111 is 2.8-3.2mm, shoulder 112 is 2.3-2.6mm, straight section 113 is 1.6-1.8mm, and bottom 114 is 2.4-2.7mm. The ratio of the maximum wall thickness to the minimum wall thickness of the bottle is ≤1.8:1. The internal pressure resistance of the beer bottle is ≥1.6MPa, the impact resistance is ≥1.0J, and the internal stress level is ≤2, which meets the requirements of national standard GB / T4544-2020.

[0048] This lightweight beer bottle features differentiated wall thickness distribution based on the actual stress characteristics of each part: the mouth needs to withstand the pressure of cap screwing and sealing, so a thicker wall is designed to ensure sealing and structural strength; the shoulder and bottom are stress concentration areas during beer bottle transportation and use, so a medium wall thickness is designed to ensure impact resistance and compression resistance; the straight cylindrical part of the bottle body experiences uniform stress, so a thin wall is designed to achieve lightweighting, ultimately achieving a scientific wall thickness distribution of "thick wall in strong areas and thin wall in weak areas," balancing lightweighting and structural strength.

[0049] Example 1 refer to Figures 1-5 As shown, a lightweight pressure blow molding method for a 500ml beer bottle based on variable wall thickness control is described, with the following specific steps: Step S1, Precise Droplet Supply: Sodium-calcium-silicon glass melt is used, and its composition by weight percentage is: SiO2 73%, Na2O 14%, CaO 9%, Al2O3 2.5%, MgO 1.2%, and clarifying agent 0.6%. The glass melt is heated to 1180℃ and quantitatively cut into 280g droplets by droplet shears. The temperature deviation of the droplets is controlled within ±8℃, and the weight deviation is controlled within ±3g. The droplets fall vertically into the closed primary mold cavity 1. Step S2, initial mold pressure pressing: A variable diameter punch 2 is used. The diameter of the lower section 21 of the punch matches the inner diameter of the mouth of a 500ml beer bottle. The upper section 22 of the punch forms an 18° cone angle. The downward speed of the punch is controlled at 18mm / s. First, the punch is driven to press down for 4s with a pressure of 0.45MPa to complete the initial shaping of the bottle mouth and preform. Then, the pressure is increased to 0.65MPa and held for 2.5s to increase the density of the preform mouth and form a preset wall thickness gradient on the shoulder. Step S3, Preform Vacuum Shaping: While the initial mold is being pressurized, the initial mold vacuum system is activated. The negative pressure of the annular vacuum groove 3 corresponding to the shoulder of the preform is adjusted to -0.05MPa, and the negative pressure of the annular vacuum groove 3 corresponding to the body of the preform is adjusted to -0.045MPa. The negative pressure deviation of each section is ≤±0.008MPa. The suction is maintained for 6s, so that the outer surface of the preform is precisely fitted to the inner wall of the initial mold cavity 1, forming a gradient preform with a mouth wall thickness of 3.0mm, a shoulder wall thickness of 2.4mm, and a body wall thickness of 2.0mm. The initial mold vacuum system includes the annular vacuum groove 3 on the inner wall of the initial mold, the vacuum pipeline 4, the negative pressure sensor, and the vacuum regulating valve.

[0050] Step S4, Preheating for Molding Transfer: The preform after shaping is rotated 180° and transferred to the molding cavity 5 by a robotic arm. The transfer time is 1.8s and the transfer positioning accuracy is ±0.15mm. During the transfer process, a 9kW infrared radiation heating device is used for preheating. The heating area fully covers the preform, so that the overall temperature of the preform is maintained at 980℃ and the temperature deviation of each part is ≤±15℃. Step S5, three-stage variable pressure blow molding: A coaxial dual-airflow channel nozzle 6 is used. The outer channel 62 is filled with auxiliary temperature-controlled gas at 450℃ and a flow rate of 6L / min, and the inner channel 61 is filled with dry compressed air (40ppm moisture content). The first stage is a low-pressure pre-blowing at 0.18MPa for 1.2s, which initially expands the preform to 80% of the volume of the molding cavity 5. During the pre-blowing stage, the punch remains stationary. The second stage is a medium-pressure controlled-thickness blow-blowing at 0.32MPa for 2.2s, which synchronously drives the punch to move upward at a speed of 6mm / s for 1.2mm to precisely control the wall thickness of the straight cylindrical part of the bottle. The third stage is a high-pressure shaping and holding at 0.55MPa for 3.2s. The punch moves downward at a speed of 12mm / s to return to its original position, so that the bottle body completely fits into the molding cavity 5 and strengthens the wall thickness of the bottom and corner parts of the bottle. Step S6, Zoned Cooling and Curing: Start the molded zoned cooling system. Cooling water at 28℃ and a flow rate of 18L / min is introduced into the straight section cooling chamber 7, with a cooling rate of 90℃ / s. Cooling water at 48℃ and a flow rate of 10L / min is introduced into the shoulder bottom cooling chamber 8, with a cooling rate of 35℃ / s. A heat insulation layer 9 is set between the straight section and the shoulder bottom. The total cooling time is 7s, which reduces the bottle temperature to 580℃. The wall thickness of the straight section of the bottle is controlled at 1.7mm, and the wall thickness of the shoulder and bottom is controlled at 2.4-2.5mm. The molded zoned cooling system includes the straight section cooling chamber 7, the shoulder bottom cooling chamber 8, an independent cooling water circuit 10, a temperature sensor, and a flow regulating valve.

[0051] Step S7, Annealing Stabilization Treatment: The molded beer bottle is sent into an annealing furnace, heated to 570°C at a rate of 5°C / min, held for 12 minutes, then cooled to 200°C at a rate of 3°C / min, and finally allowed to cool naturally to room temperature to eliminate stress inside the bottle. Step S8, Online Inspection and Sorting: A system combining laser wall thickness detection and 20-megapixel high-definition vision inspection is adopted. The laser detection accuracy is ±0.05mm, and the detection speed is 650 bottles / minute. It detects the uniformity of bottle wall thickness and appearance defects, and identifies microcracks larger than 0.1mm and bubbles larger than 0.2mm. Qualified products enter the next process, and unqualified products are crushed and recycled.

[0052] The lightweight 500ml beer bottle produced in this embodiment weighs 270g, a 20.6% reduction compared to the traditional 340g beer bottle. The wall thickness distribution across the bottle is as follows: mouth 1113.0mm, shoulder 1122.4mm, cylindrical body 1131.7mm, and bottom 1142.5mm, with a thickness-to-thickness ratio of 1.5:1. Testing shows that the beer bottle has an internal pressure resistance of 1.7MPa, an impact resistance of 1.1J, and an internal stress level of 1, all exceeding the requirements of the national standard GB / T4544-2020. This embodiment achieves a production defect rate of 2.3%, a reduction of over 70% compared to traditional processes, a 21% reduction in raw material consumption, an 18.5% reduction in kiln energy consumption, and a reduction of 0.07 yuan per bottle in production cost.

[0053] Example 2 refer to Figures 1-5 As shown, a lightweight pressure blow molding method for a 500ml beer bottle based on variable wall thickness control is described, with the following specific steps: Step S1, precise supply of droplets: The composition of the sodium-calcium-silicon glass melt by weight percentage is: SiO2 72%, Na2O 15%, CaO 8%, Al2O3 3%, MgO 1%, clarifying agent 0.8%. It is heated to 1150℃, sheared into 270g droplets, with a temperature deviation of ±10℃ and a weight deviation of ±5g, and vertically dropped into the primary mold cavity 1. Step S2, Initial mold pressure pressing: The variable diameter punch has a cone angle of 15° and a downward speed of 15mm / s. First, it is pressed down with a pressure of 0.4MPa for 5s, and then the pressure is increased to 0.6MPa and held for 3s; Step S3, Preform vacuum shaping: The negative pressure at the shoulder is -0.04MPa, and the negative pressure at the body is -0.04MPa, which is maintained for 8s to form a gradient preform with a mouth wall thickness of 2.8mm, a shoulder wall thickness of 2.2mm, and a body wall thickness of 1.9mm; Step S4, Preheating for mold transfer: The robot transfer time is 1.5s, the positioning accuracy is ±0.2mm, and the 8kW infrared preheating brings the preform temperature to 950℃ with a temperature deviation of ±20℃. Step S5, three-stage variable pressure blow molding: auxiliary temperature control gas 400℃, flow rate 5L / min, forming gas moisture content 50ppm; first stage 0.15MPa pre-blowing for 1.5s, punch stationary; second stage 0.30MPa thickness control blowing for 2.5s, punch moves upward 1.0mm at 5mm / s; third stage 0.50MPa pressure holding for 3.5s, punch moves downward back to position at 10mm / s. Step S6, zoned cooling and curing: 25℃ cooling water for the straight section, flow rate 15L / min, cooling rate 80℃ / s; 45℃ cooling water for the shoulder bottom, flow rate 8L / min, cooling rate 30℃ / s; total cooling time 8s, bottle temperature drops to 550℃, straight section wall thickness 1.6mm, shoulder bottom wall thickness 2.3mm; Step S7, Annealing and stabilization treatment: Hold at 560℃ for 15 min, cool down to 200℃ at 3℃ / min, and allow to cool naturally to room temperature; Step S8, online inspection and sorting: laser inspection + high-definition visual inspection, inspection speed 600 bottles / minute, sorting out unqualified products.

[0054] The lightweight beer bottle produced in this embodiment weighs 260g, a weight reduction of 23%; the bottle thickness ratio is 1.6:1, the internal pressure resistance is 1.6MPa, the impact resistance is 1.0J, and the internal stress level is 2, which meets the national standard requirements; the production defect rate is 2.8%, raw material consumption is reduced by 20%, energy consumption is reduced by 18%, and the production cost per bottle is reduced by 0.05 yuan.

[0055] Example 3 refer to Figures 1-5 A lightweight pressure blow molding method for 500ml beer bottles based on variable wall thickness control, the specific steps of which are as follows: Step S1, precise supply of droplets: The composition of the sodium-calcium-silicon glass melt by weight percentage is: SiO2 74%, Na2O 13%, CaO 10%, Al2O3 2%, MgO 2%, clarifying agent 0.5%. It is heated to 1200℃, sheared into 290g droplets, with a temperature deviation of ±5℃ and a weight deviation of ±2g, and vertically dropped into the primary mold cavity 1. Step S2, initial mold pressure compression: the variable diameter punch has a cone angle of 20°, a downward speed of 20mm / s, first press down with 0.5MPa pressure for 3s, then increase the pressure to 0.7MPa and hold for 2s; Step S3, preform vacuum shaping: shoulder negative pressure -0.06MPa, body negative pressure -0.05MPa, maintained for 5s, forming a gradient preform with a mouth wall thickness of 3.2mm, a shoulder wall thickness of 2.5mm, and a body wall thickness of 2.1mm; Step S4, Preheating for mold transfer: The robot transfer time is 2.0s, the positioning accuracy is ±0.1mm, and the 10kW infrared preheating brings the preform temperature to 1000℃ with a temperature deviation of ±10℃. Step S5, three-stage variable pressure blow molding: auxiliary temperature control gas 500℃, flow rate 8L / min, forming gas moisture content 30ppm; first stage 0.20MPa pre-blowing for 1.0s, punch stationary; second stage 0.35MPa thickness control blowing for 2.0s, punch moves upward 1.5mm at 8mm / s; third stage 0.60MPa pressure holding for 3.0s, punch moves downward back to position at 15mm / s. Step S6, zoned cooling and curing: 30℃ cooling water for the straight section, flow rate 20L / min, cooling rate 100℃ / s; 50℃ cooling water for the shoulder bottom, flow rate 12L / min, cooling rate 40℃ / s; total cooling time 6s, bottle temperature drops to 600℃, straight section wall thickness 1.8mm, shoulder bottom wall thickness 2.6mm; Step S7, Annealing and stabilization treatment: Hold at 580℃ for 10 min, cool down to 200℃ at 3℃ / min, and allow to cool naturally to room temperature; Step S8, online inspection and sorting: laser inspection + high-definition visual inspection, inspection speed 700 bottles / minute, sorting out unqualified products.

[0056] The lightweight beer bottle produced in this embodiment weighs 280g, a weight reduction of 15%; the bottle thickness ratio is 1.8:1, the internal pressure resistance is 1.8MPa, the impact resistance is 1.2J, and the internal stress level is Grade 1, which is better than the national standard requirements; the production defect rate is 2.0%, raw material consumption is reduced by 22%, energy consumption is reduced by 19%, and the production cost per bottle is reduced by 0.08 yuan.

[0057] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lightweight pressure blow molding method for beer bottles based on variable wall thickness control, characterized in that, Includes the following steps: Step S1, Precise Droplet Supply: The sodium-calcium-silicon glass melt droplet with a temperature of 1150-1200℃ and a weight of 270-290g is quantitatively cut by a droplet shear and then vertically dropped into the closed primary mold cavity. Step S2, initial mold pressure control: segmented pressure control is adopted. First, the punch is driven to press down for 3-5 seconds with a pressure of 0.4-0.5MPa to complete the initial shaping of the bottle mouth and preform. Then, the pressure is increased to 0.6-0.7MPa and held for 2-3 seconds to increase the density of the preform mouth and form a preset wall thickness gradient at the shoulder. Step S3, Preform Vacuum Shaping: While maintaining the pressure of the initial mold, the initial mold vacuum system is activated to draw out the gap between the preform and the mold cavity with a negative pressure of -0.04 to -0.06 MPa for 5-8 seconds, so that the outer surface of the preform is precisely attached to the inner wall of the initial mold, forming a gradient preform with a mouth wall thickness of 2.8-3.2 mm, a shoulder wall thickness of 2.2-2.5 mm, and a body wall thickness of 1.9-2.1 mm; Step S4, Preheating for Molding Transfer: The shaped preform is transferred to the molding cavity by rotating it 180° using a robotic arm. The transfer time is controlled at 1.5-2.0s. During the transfer process, the preform is preheated with infrared light to maintain the overall temperature of the preform at 950-1000℃ to avoid uneven temperature. Step S5, Three-stage variable pressure blow molding: Three stages of differentiated pressure airflow are sequentially introduced into the preform. The first stage is low-pressure pre-blowing: 0.15-0.20MPa airflow is blown for 1.0-1.5s to initially expand the preform to 80% of the mold cavity volume; the second stage is medium-pressure thickness control: 0.30-0.35MPa airflow is blown for 2.0-2.5s, combined with mold zone temperature control, to precisely control the wall thickness of the straight cylindrical part of the bottle; the third stage is high-pressure shaping: 0.50-0.60MPa airflow is held for 3.0-3.5s to make the bottle body completely fit the mold cavity and strengthen the wall thickness of the bottom and corner parts of the bottle. Step S6, Zoned Cooling and Curing: Activate the molded zoned cooling system. Use 25-30℃ cooling water for rapid cooling of the straight cylindrical part of the bottle body at a cooling rate of 80-100℃ / s, controlling the wall thickness to 1.6-1.8mm; use 45-50℃ cooling water for slow cooling of the bottle shoulder and bottom at a cooling rate of 30-40℃ / s, controlling the wall thickness to 2.3-2.6mm; the total cooling time is 6-8s, reducing the bottle temperature to 550-600℃. Step S7, Annealing Stabilization Treatment: The molded beer bottle is sent into an annealing furnace, heated to 560-580℃ at a rate of 5℃ / min and held for 10-15min, then cooled to 200℃ at a rate of 3℃ / min, and finally allowed to cool naturally to room temperature to eliminate internal stress. Step S8, online inspection and sorting: The uniformity of wall thickness and appearance defects are detected by a vision inspection system. Qualified products enter the next process, and unqualified products are crushed and recycled.

2. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S1, the composition of the sodium-calcium-silicon glass melt by weight percentage is: SiO2 72-74%, Na2O 13-15%, CaO 8-10%, Al2O3 2-3%, MgO 1-2%, and clarifying agent 0.5-0.8%. The temperature deviation of the droplets is controlled within ±10℃, and the weight deviation of the droplets is controlled within ±5g.

3. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S2, the punch has a variable diameter structure. The diameter of the lower section of the punch matches the inner diameter of the beer bottle mouth. The diameter of the upper section of the punch gradually decreases in the direction away from the lower section, forming a cone angle of 15°-20°. During the pressing process, the downward speed of the punch is controlled at 15-20 mm / s, and the uniformity deviation of the gap between the punch and the initial mold cavity is ≤ ±0.1 mm.

4. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S3, the initial mold vacuum system includes an annular vacuum groove on the inner wall of the initial mold, vacuum pipeline, negative pressure sensor and vacuum regulating valve. The annular vacuum groove is set in sections along the bottle shoulder and bottle body of the preform. Each section of the annular vacuum groove is connected to an independent vacuum regulating valve and a negative pressure sensor. The negative pressure of each section is independently controlled, and the negative pressure deviation is ≤ ±0.01MPa.

5. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S4, infrared preheating uses an infrared radiation heating device with a heating power of 8-10kW. The heating area fully covers the outer surface of the preform, and the temperature uniformity deviation of each part of the preform is ≤±20℃. The transfer positioning accuracy of the robotic arm is ≤±0.2mm.

6. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S5, the three-stage variable pressure blowing adopts a nozzle structure with a coaxial dual airflow channel. The inner channel is filled with high-pressure forming gas, and the outer channel is filled with auxiliary temperature control gas. The temperature of the auxiliary temperature control gas is 400-500℃ and the flow rate is 5-8L / min, which prevents uneven glass crystallization caused by local rapid cooling during the preform blowing process. The forming gas is dry compressed air with a moisture content of ≤50ppm.

7. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S5, during the three-stage variable pressure blowing process, the synchronously driven punch performs dynamic compensation up and down. During the pre-blowing stage, the punch remains stationary. During the thickness control stage, the punch moves upward at a speed of 5-8 mm / s for 1.0-1.5 mm. During the shaping stage, the punch moves downward at a speed of 10-15 mm / s to return to its original position. By adjusting the forming space inside the preform through the dynamic movement of the punch, the wall thickness of each part is precisely controlled.

8. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S6, the molded partition cooling system includes a straight cylinder cooling chamber, a shoulder bottom cooling chamber, an independent cooling water circuit, a temperature sensor, and a flow regulating valve. A heat insulation layer is set between the straight cylinder cooling chamber and the shoulder bottom cooling chamber for thermal isolation. The flow rate of the straight cylinder cooling water circuit is 15-20 L / min, and the flow rate of the shoulder bottom cooling water circuit is 8-12 L / min. The water temperature and flow rate of each circuit are controlled in real time by the temperature sensor and the flow regulating valve, with deviations of ≤±2℃ and ±1L / min, respectively.

9. The lightweight pressure blow molding method for beer bottles based on variable wall thickness control according to claim 1, characterized in that, In step S8, the online inspection adopts an inspection system that combines laser wall thickness inspection and high-definition vision inspection. The accuracy of laser wall thickness inspection is ±0.05mm, and the resolution of high-definition vision inspection is ≥20 million pixels. The inspection speed of the inspection system is ≥600 bottles / minute, and it can identify microcracks larger than 0.1mm, bubbles larger than 0.2mm in diameter, and appearance defects such as missing material and cold lines on the bottle surface.

10. A lightweight beer bottle based on variable wall thickness control, characterized in that, The beer bottle is manufactured using the lightweight pressure blow molding method based on variable wall thickness control as described in any one of claims 1-9. The nominal volume of the beer bottle is 500ml, and the overall weight is 260-280g. The wall thickness distribution of each part of the bottle body is as follows: mouth size 2.8-3.2mm, shoulder size 2.3-2.6mm, straight cylinder size 1.6-1.8mm, bottom size 2.4-2.7mm, and the ratio of the maximum wall thickness to the minimum wall thickness of the bottle body is ≤1.8:1.

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