High-transparency injection molding process for medical device transparent housing

Abstract

The application discloses a high-transparency blister forming process for a medical equipment transparent shell and relates to the technical field of the blister forming of medical equipment transparent shells, and specifically comprises the following steps: S1, medical-grade plate selection and dust-free activation pretreatment: high-transparency and scratch-resistant PETG composite plates are selected, and the transmittance and haze of the raw materials are sampled before being stored in the warehouse to screen qualified plates with a transmittance of greater than or equal to 92% and a haze of less than or equal to 0.8%. The high-transparency blister forming process for the medical equipment transparent shell completely removes oil stains, release agents, dust and static electricity residues on the surface of the plate through plate selection and plasma and ultrasonic composite pretreatment processes in a ten-thousand-level dust-free environment, prevents light-transmission defects and haze out-of-tolerance problems caused by impurities and static electricity, cooperates with three-stage gradient flexible heating technology, discards the drawbacks of traditional single-temperature heating, accurately controls the plate heating rhythm and overall temperature difference, and effectively avoids the yellowing and fogging of the transparent plate during heating.

Description

Technical Field

[0001] This invention relates to the field of thermoforming technology for transparent shells of medical devices, specifically a high-transmittance thermoforming process for transparent shells of medical devices. Background Technology

[0002] Transparent shells for medical devices are mostly made of transparent sheets such as PETG and PVC through vacuum forming. Because they are directly exposed on the surface of the equipment and are used in medical diagnosis and treatment scenarios, there are extremely high requirements for the product's light transmittance, haze, surface cleanliness, appearance flatness and structural stability.

[0003] Currently, traditional transparent shell vacuum forming processes generally suffer from numerous technical defects. The industry's conventional process often adopts a production mode of single constant temperature heating, instantaneous negative pressure vacuum forming, rapid water cooling and shaping, and manual hand-trimming. During the heating process of the sheet material, excessive local temperature differences can easily occur, leading to yellowing, fogging, and uneven softening of the sheet material. Instantaneous negative pressure stretching during forming can easily cause uneven distribution of shell wall thickness and large differences in local light transmission, seriously affecting the overall transparency and consistency of the machine. At the same time, the traditional rapid cooling method leaves a large amount of residual stress inside the product, which can easily lead to quality problems such as warping, deformation, and micro-cracks after long-term use.

[0004] Therefore, in view of this, we have studied and improved the existing structure and its shortcomings, and proposed a high-transmittance vacuum forming process for transparent shells of medical devices. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-transmittance vacuum forming process for transparent shells of medical devices, solving the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-transmittance vacuum forming process for a transparent shell of medical devices, specifically comprising the following steps: S1. Medical-grade board selection and dust-free activation pretreatment: High-transmittance and scratch-resistant PETG composite boards are selected. Before the raw materials are put into storage, the transmittance and haze are sampled and tested. Qualified boards with transmittance ≥92% and haze ≤0.8% are selected. The boards are placed in a Class 10,000 dust-free constant temperature workshop and a double-sided low-temperature plasma activation and ultrasonic spray composite decontamination process is adopted to remove oil stains, release agents, micro dust and static electricity residues from the board surface. After treatment, the boards are sealed and left to stand for later use to prevent secondary pollution. S2. Segmented constant temperature and gentle heating: The upper and lower independent temperature-controlled infrared radiation heating system is used to heat in three stages: low temperature preheating, constant temperature uniform heating, and shaping and heat preservation. This accurately controls the overall temperature of the board, eliminates the temperature difference between the inside and outside of the board and the problem of local overheating, avoids yellowing, fogging and thermal deformation defects of transparent boards, and ensures uniform softening and stable molecular stress of the board. S3. Mirror-finish mold dustproof and mold closing positioning: Adopts a cavity mirror-polished mold with a smooth inner wall roughness. m, the mold is preheated with dust-free air blowing in advance to avoid condensation and fogging on the surface of the sheet material due to temperature difference in the mold; the sheet material is evenly clamped and positioned on all four sides by an adjustable elastic pressure frame to prevent the sheet material from shifting or loosening after heating, and to ensure the molding alignment accuracy. S4. Air pressure pre-stretching and graded negative pressure vacuum forming: First, low-pressure positive air pressure is used for pre-stretching to make the sheet evenly expand and extend, and optimize the sheet wall thickness distribution. Then, a graded negative pressure vacuuming process is used to gradually increase the vacuum degree, avoiding problems such as uneven sheet stretching, local thinning and abnormal light transmission caused by instantaneous negative pressure, so that the sheet can be completely fitted to the mold cavity for fine forming. S5. Layered water-cooled slow-release shaping: It adopts a labyrinth-style circulating water-cooling structure inside the mold, with segmented gradient cooling, and a small amount of air cooling to assist uniform cooling. Unlike the traditional rapid cooling process, it effectively releases the internal forming stress of the sheet material, eliminates the problems of warping, deformation and cracking of the transparent shell in the later stage, and at the same time ensures the flatness of the shell surface and high light transmittance. S6. Aseptic Post-processing and Optical Inspection: After demolding, the molded shell is immediately placed in the tooling fixture for fitting, positioning and fixing, constraining shell displacement and micro-deformation, and avoiding deformation, uneven chamfering and surface scratches in subsequent processing. After fixing, dust-free precision trimming and rounded chamfering are performed to remove burrs and sharp edges. Then, high-frequency electrostatic dust removal and dust-free air drying are performed. Finally, each piece is subjected to optical inspection for light transmittance, haze and flatness to screen qualified transparent shell products for medical equipment.

[0007] Furthermore, the S1 drying device adopts a three-stage gradient constant temperature drying process: the first stage preheating temperature is 45-55℃ for 1 hour, the second stage constant temperature dehumidification temperature is 70-80℃ for 3-4 hours, and the third stage cooling and stabilizing temperature is 55-60℃ for 1 hour. After drying, the moisture content of the raw material is strictly controlled to ≤0.015%. The raw material is one of medical PC, medical PC / ABS, and medical antibacterial PP. The melt index of the raw material is controlled at 18-35g / 10min, which is suitable for thin-walled high-speed filling molding requirements.

[0008] Furthermore, in S1, the thickness of the PETG composite board is 1.5-3.0mm, the surface hardness is ≥3H, the scratch resistance level meets the standards for medical device shells, the plasma activation treatment power is 90-130W, and the ultrasonic spraying uses purified water at low temperature with a processing speed of 0.3-0.6m / min.

[0009] Furthermore, the three-stage gradient heating parameters in S2 are as follows: preheating stage temperature 85-105℃, duration 4-6s; uniform heating stage temperature 120-135℃, duration 8-12s; heat preservation and shaping stage temperature 115-120℃, duration 3-5s; and the overall temperature difference of the board is controlled ≤±2℃.

[0010] Furthermore, in S4, the pre-blowing pressure is 0.02-0.05MPa, and the pre-blowing time is 2-5s; the graded negative pressure forming is divided into three stages: low-pressure forming, high-pressure bonding, and pressure stabilization and shaping, with vacuum degrees of -0.05MPa, -0.08MPa, and -0.09MPa respectively, and a total pressure holding time of 10-18s, effectively optimizing the uniformity of the outer shell wall thickness, and controlling the overall wall thickness error within ±0.1mm.

[0011] Furthermore, in S5, the gradient water cooling temperatures are 38℃, 32℃, and 26℃ respectively, and the segmented cooling times are 6s, 5s, and 4s respectively. The slow-release cooling method is used to eliminate the internal stress of the sheet metal, and the residual internal stress rate of the shell after molding is less than 5%.

[0012] Furthermore, the tooling fixture in step S6 includes an upper frame and an adjusting plate. A lower frame is installed below the upper frame, and a hydraulic rod is provided at the bottom center of the upper frame. A connecting plate is installed at the output end of the hydraulic rod, and a fixing plate is distributed in a ring on the outer surface of the connecting plate. The adjusting plate is slidably disposed on the outer surface of the fixing plate. An auxiliary component for assisting in adjusting the length between the fixing plate and the adjusting plate is installed inside the fixing plate. The auxiliary component includes a bevel gear one, a bevel gear two, and a lead screw. The bottom of the bevel gear one is meshed with the bevel gear two, and a lead screw is fixedly disposed at the center of one side of the bevel gear two.

[0013] Furthermore, the lead screw is threadedly connected to the adjusting plate, and the adjusting plate and the lead screw are distributed in a one-to-one correspondence.

[0014] Furthermore, both the upper and lower frames are equipped with length adjustment components for synchronously adjusting the fixed plate and the adjustment plate. The adjustment components include a driving gear and a driven gear. The outer surface of the driving gear is meshed with six sets of driven gears, and a rod two is fixedly installed in the middle of the driven gear. A rod one is slidably installed in the middle of the rod two, and the external shape of the rod one matches the internal shape of the rod two.

[0015] Furthermore, the upper frame is provided with a drive assembly for providing driving force, and the drive assembly includes a drive motor, a drive roller, a transmission roller, a connecting shaft, and a transmission component. The output end of the drive motor is equipped with a drive roller, and the outer surface of the drive roller is equipped with a transmission roller via belt drive. The middle of the transmission roller is equipped with a connecting shaft, and the bottom of the connecting shaft is equipped with a transmission component.

[0016] Furthermore, the transmission assembly is consistent with the transmission structure composed of the drive roller, the transmission roller, and the belt, and mounting plates are fixedly installed on the outer surfaces of both the upper and lower frames.

[0017] This invention provides a high-transmittance vacuum forming process for transparent shells of medical devices, which has the following beneficial effects: 1. The high-transmittance vacuum forming process of the transparent shell of this medical device utilizes a Class 10,000 cleanroom environment for material selection and plasma and ultrasonic composite pretreatment processes. This process thoroughly removes oil stains, mold release agents, micro-dust, and static electricity residues from the surface of the material, eliminating light transmission defects and haze issues caused by impurities and static electricity. Combined with three-stage gradient flexible heating technology, it abandons the drawbacks of traditional single-temperature heating, precisely controlling the heating rhythm and overall temperature difference of the material. This effectively avoids yellowing and haze phenomena caused by heating of the transparent material. The combination of air pressure pre-stretching and graded negative pressure vacuum forming processes makes the stretching and extension of the material more uniform, and the shell wall thickness error is controlled within ±0.1mm. This completely solves the defects of uneven local light transmission and light transmission attenuation defects at thin edges. In addition, the ultra-low roughness mirror mold and the dust-free preheating treatment of the mold before forming eliminate surface ripples and stains caused by mold dust and temperature difference condensation.

[0018] 2. The high-transmittance vacuum forming process of the transparent shell of this medical device adopts a labyrinthine segmented gradient water cooling combined with micro-air cooling for slow-release shaping. Through a stepped cooling mode, the molecular structure of the sheet material is slowly shaped and the stress is gradually released, so that the residual stress rate inside the shell after molding is less than 5%. This fundamentally solves the common quality problems of warping, deformation and cracking during the storage and use of finished products. At the same time, the entire molding process is precisely positioned and uniformly stretched by an elastic pressure frame to ensure the dimensional accuracy and surface flatness of the shell, which greatly improves the structural stability and service life of the product and effectively reduces the after-sales failure rate.

[0019] 3. The high-transparency vacuum forming process for the transparent shell of this medical device, through the cooperation of gear sets, lead screws, and linkage adjustment components, enables stepless and precise adjustment of the clamping size, with multi-directional synchronous adjustment and consistent accuracy. It can adapt to the processing of medical transparent shells of different specifications, significantly improving tooling versatility and reducing equipment changeover costs. The tooling adopts a flexible clamping method, only clamping the waste edge area of ​​the shell, effectively avoiding the side wall, bottom edge trimming, and chamfering processing areas, preventing tooling interference with processing steps, and ensuring the shell's complete and flat appearance and high light transmittance. Simultaneously, the tooling integrates a pressure monitoring structure, which can accurately control the clamping pressure in real time. This prevents excessive pressure from causing shell indentations, deformation, and residual internal stress, while also preventing insufficient pressure from causing clamping loosening and processing misalignment. Combined with an integrated linkage transmission structure, it enables automated and precise adjustment, reducing human error, improving processing stability and production efficiency, adapting to large-scale production, and effectively reducing product defect rates. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process structure for high-transparency vacuum forming of a transparent shell for a medical device according to the present invention. Figure 2 This is a schematic diagram of the tooling fixture structure for a high-transparency vacuum forming process of a transparent shell for a medical device according to the present invention. Figure 3 This is a schematic diagram of the tooling fixture for a high-transparency vacuum forming process of a transparent shell for a medical device according to the present invention, from another perspective. Figure 4 This is a partial cross-sectional view of the connection between the fixing plate and the adjusting plate in the high-transparency vacuum forming process of a transparent shell for a medical device according to the present invention. Figure 5 This is a schematic diagram of the drive component structure for a high-transparency vacuum forming process of a transparent shell for a medical device according to the present invention. Figure 6 This invention relates to a high-transmittance vacuum forming process for a transparent shell of a medical device. Figure 3 Enlarged structural diagram at point A in the middle; Figure 7 This is a schematic diagram of the auxiliary component structure of a high-transparency vacuum forming process for a transparent shell of a medical device according to the present invention.

[0021] In the diagram: 1. Upper frame; 2. Lower frame; 3. Mounting plate; 4. Hydraulic rod; 5. Connecting plate; 6. Rod one; 7. Adjusting assembly; 701. Driving gear; 702. Driven gear; 8. Fixing plate; 9. Adjusting plate; 10. Drive assembly; 1001. Drive motor; 1002. Driving roller; 1003. Transmission roller; 1004. Connecting shaft; 1005. Transmission assembly; 11. Auxiliary assembly; 1101. Bevel gear one; 1102. Bevel gear two; 1103. Lead screw; 12. Rod two. Detailed Implementation

[0022] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0023] like Figures 1-7 As shown, the present invention provides a technical solution: a high-transparency vacuum forming process for a transparent shell of medical devices, specifically including the following steps: S1. Medical-grade board material selection and dust-free activation pretreatment: High-transmittance and scratch-resistant PETG composite boards are selected. Before the raw materials are put into storage, the transmittance and haze are sampled and tested. Qualified boards with transmittance ≥92% and haze ≤0.8% are selected. The boards are placed in a Class 10,000 dust-free constant temperature workshop and a double-sided low-temperature plasma activation and ultrasonic spray composite decontamination process is adopted to remove oil stains, release agents, micro dust and static electricity residues from the board surface. After treatment, the boards are sealed and left to stand for later use to prevent secondary pollution. The thickness of the PETG composite board in S1 is 1.5-3.0mm, the surface hardness is ≥3H, and the scratch resistance level meets the standards for medical equipment shells. The plasma activation power is 90-130W, and the ultrasonic spray uses purified water low-temperature spray with a processing speed of 0.3-0.6m / min. S2, Segmented Constant Temperature Gentle Heating: Employs an independent upper and lower temperature-controlled infrared radiation heating system, with three-segment gradient heating: low-temperature preheating, constant temperature uniform heating, and shaping and heat preservation. This precisely controls the overall temperature of the board, eliminating temperature differences between the inside and outside of the board and local overheating issues. It avoids defects such as yellowing, fogging, and thermal deformation of transparent boards, ensuring uniform softening and stable molecular stress. The three-segment gradient heating parameters in S2 are: preheating stage temperature 85-105℃, duration 4-6s; uniform heating stage temperature 120-135℃, duration 8-12s; and heat preservation and shaping stage temperature 115-120℃, duration 3-5s. The overall temperature difference of the board is controlled to ≤±2℃. S3. Mirror-finish mold dustproof and mold closing positioning: Adopts a cavity mirror-polished mold with a smooth inner wall roughness. m, the mold is preheated with dust-free air blowing in advance to avoid condensation and fogging on the surface of the sheet material due to temperature difference in the mold; the sheet material is evenly clamped and positioned on all four sides by an adjustable elastic pressure frame to prevent the sheet material from shifting or loosening after heating, and to ensure the molding alignment accuracy. S4. Pre-stretching and graded negative pressure vacuum forming: First, low-pressure positive air pressure is used for pre-stretching to make the sheet material expand and extend evenly, optimizing the sheet material wall thickness distribution. Then, a graded negative pressure vacuuming process is used to gradually increase the vacuum degree, avoiding problems such as uneven sheet material stretching, local thinning and abnormal light transmission caused by instantaneous negative pressure. This ensures that the sheet material fits perfectly into the mold cavity for precise forming. In S4, the pre-blowing air pressure is 0.02-0.05MPa, and the pre-blowing time is 2-5s. The graded negative pressure forming is divided into three stages: low-pressure forming, high-pressure bonding, and pressure stabilization and shaping. The vacuum degrees are -0.05MPa, -0.08MPa, and -0.09MPa respectively, with a total holding time of 10-18s. This effectively optimizes the uniformity of the shell wall thickness, and the overall wall thickness error is controlled within ±0.1mm. S5, Layered Water-Cooled Slow-Release Shaping: Utilizing an internal labyrinthine circulating water-cooling structure, this process employs segmented gradient cooling, supplemented by micro-air cooling for uniform cooling. Unlike traditional rapid cooling processes, it effectively releases internal forming stress in the sheet material, preventing warping, deformation, and cracking of the transparent shell later on. Simultaneously, it ensures the shell's surface flatness and high light transmittance. In S5, the gradient water-cooling temperatures are 38℃, 32℃, and 26℃, with segmented cooling times of 6s, 5s, and 4s respectively. The slow-release cooling method eliminates internal stress in the sheet material, resulting in a residual internal stress rate of less than 5% after molding. S6. Aseptic Post-processing and Optical Inspection: After demolding, the molded shell is immediately placed in the tooling fixture for fitting, positioning, and fixation. This constrains shell displacement and micro-deformation, preventing deformation, uneven chamfering, and surface scratches during subsequent processing. After fixation, dust-free precision trimming and rounded chamfering are performed to remove burrs and sharp edges. High-frequency electrostatic dust removal and dust-free air drying are then carried out. Finally, each piece undergoes optical inspection for transmittance, haze, and flatness to select qualified transparent medical device shells. The tooling fixture in step S6 includes upper frame 1, lower frame 2, and mounting brackets. The components include: mounting plate 3, hydraulic rod 4, connecting plate 5, rod one 6, adjusting assembly 7, driving gear 701, driven gear 702, fixed plate 8, adjusting plate 9, drive assembly 10, drive motor 1001, driving roller 1002, transmission roller 1003, connecting shaft 1004, transmission assembly 1005, auxiliary assembly 11, bevel gear one 1101, bevel gear two 1102, lead screw 1103, and rod two 12. A lower frame 2 is installed below the upper frame 1, and a hydraulic rod 4 is located at the bottom center of the upper frame 1. A connecting rod 4 is installed at its output end. The connecting plate 5 has a ring of fixed plates 8 on its outer surface. An adjusting plate 9 is slidably disposed on the outer surface of the fixed plates 8. An auxiliary component 11 for assisting in adjusting the length between the fixed plates 8 and the adjusting plate 9 is installed inside the fixed plates 8. The auxiliary component 11 includes a bevel gear 1101, a bevel gear 1102, and a lead screw 1103. The bottom of the bevel gear 1101 is meshed with the bevel gear 1102. The lead screw 1103 is fixedly disposed on the middle of one side of the bevel gear 1102. The lead screw 1103 is threaded onto the adjusting plate 9. The connection is such that the adjusting plate 9 and the lead screw 1103 are distributed in a one-to-one correspondence. The auxiliary component 11 works synchronously to adjust the operation. The bevel gear 1101 meshes and drives the bevel gear 2 1102 to rotate, which in turn drives the fixed lead screw 1103 to rotate. Utilizing the threaded engagement structure between the lead screw 1103 and the adjusting plate 9, the adjusting plate 9 is driven to slide smoothly on the surface of the fixed plate 8, and the combined length of the fixed plate 8 and the adjusting plate 9 is precisely adjusted. Combined with the four-sided synchronous adjustment structure, the tooling clamping size can be infinitely adjusted, which can be adapted to medical transparent shells of different lengths and widths. After the size adjustment is completed, the hydraulic rod 4 drives the ring-shaped fixed plate 8 and the adjusting plate 9 to press down as a whole through the connecting plate 5. The connecting plate 5 is integrated with a pressure sensor in the middle. During the process of the fixed plate 8 and adjusting plate 9 on the upper frame 1 side approaching and pressing the transparent shell towards the fixed plate 8 and adjusting plate 9 on the lower frame 2 side, the pressure sensor dynamically monitors the pressing pressure value in real time. It can accurately feed back the clamping pressure, avoid excessive pressure causing the transparent shell to be squeezed and deformed, generate internal stress or surface indentation, and avoid the problem of loose clamping and processing deviation caused by insufficient pressure.The tooling only constrains the displacement and slight deformation of the shell, completely avoiding the trimming and chamfering areas of the shell's side walls and bottom edge. Both the upper frame 1 and the lower frame 2 are equipped with length adjustment components 7 for synchronously adjusting the length between the fixed plate 8 and the adjusting plate 9. Each adjustment component 7 includes a driving gear 701 and a driven gear 702. Six sets of driven gears 702 mesh with the outer surface of the driving gear 701, and a rod 12 is fixedly mounted in the middle of each driven gear 702. A rod 6 is slidably mounted in the middle of the rod 12. Furthermore, the external shape and structure of rod 6 match the internal shape and structure of rod 12. A drive assembly 10 for providing driving force is provided on the outside of the upper frame 1. The drive assembly 10 includes a drive motor 1001, a drive roller 1002, a transmission roller 1003, a connecting shaft 1004, and a transmission component 1005. The output end of the drive motor 1001 is equipped with the drive roller 1002, and the outer surface of the drive roller 1002 is equipped with a transmission roller 1003 via a belt drive. A connecting shaft 1004 is installed in the middle of the device. A transmission assembly 1005 is installed at the bottom of the connecting shaft 1004. The transmission assembly 1005 is consistent with the transmission structure consisting of the drive roller 1002, the transmission roller 1003 and the belt. Mounting plates 3 are fixedly installed on the outer surfaces of the upper frame 1 and the lower frame 2. The upper frame 1 and the lower frame 2 are fixedly installed as a whole through the mounting plates 3. After the device is started, the drive motor 1001 in the drive assembly 10 outputs power to drive the drive roller 1002 to rotate. The drive roller 1002 drives the transmission roller 1003 to rotate synchronously through the belt, so that the connecting shaft 1004 is linked to the transmission assembly 1005 to operate, providing stable transmission power for the overall adjustment structure. The transmission structure is linked to the adjustment assembly 7 to work, causing the drive gear 701 to mesh and drive the six sets of driven gears 702 to rotate synchronously. The driven gears 702 drive the rod 12 to rotate. In conjunction with the rod 6, which is structurally adapted to and slidably installed with the rod 12, multiple sets of adjustment structures are linked synchronously to ensure uniform adjustment accuracy around the device.

[0024] In summary, as Figures 1-7As shown, the high-transparency vacuum forming process of the transparent shell of this medical device involves several steps. First, medical-grade PETG composite sheets with high light transmittance, low haze, and high hardness are selected through a rigorous process. Then, a combination of low-temperature plasma activation and ultrasonic spraying in a Class 10,000 cleanroom environment is used to thoroughly remove impurities, oil, and static electricity residue from the sheet surface, preventing dirt and light transmittance defects in the finished product from the outset. Secondary contamination is prevented by sealing and allowing the material to stand still. Subsequently, a three-stage gradient flexible heating mode with independent upper and lower temperature control is employed. This segmented temperature control, including preheating, uniform heating, and heat preservation, minimizes temperature differences between the inside and outside of the sheet and in specific areas. This process ensures the entire sheet material softens uniformly, preventing yellowing, fogging, and thermal deformation of transparent sheets at high temperatures, and guaranteeing uniform and stable molecular stress. A low-roughness mirror-finish mold, combined with dust-free preheating and elastic pressure frame positioning, eliminates condensation and fogging issues caused by temperature differences in the mold, ensuring precise alignment and preventing misalignment during forming. In the forming stage, low-pressure positive air pre-blowing first causes the sheet material to expand and extend uniformly, optimizing the initial wall thickness distribution. Then, a graded, progressive negative pressure vacuuming process replaces the traditional instantaneous negative pressure forming method, preventing localized stretching and thinning of the sheet material and abnormal light transmission, ensuring precise fit of the sheet material to the mold cavity. After fine molding, the mold utilizes a labyrinthine water-cooling system combined with a small amount of air cooling to achieve segmented gradient cooling, slowly releasing the molding stress within the sheet metal in a stepped cooling manner. This effectively solves defects such as warping, deformation, and cracking in the finished product, ensuring the flatness and light transmission consistency of the shell surface. Immediately after demolding, a dedicated adjustable tooling fixture is used to flexibly position and fix the shell. This fixture achieves overall assembly and positioning through the upper frame 1, lower frame 2, and mounting plate 3. Power is provided by the drive component 10, and the power is transmitted through the active roller 1002, transmission roller 1003, connecting shaft 1004, and transmission components. 1005 completes the power transmission, coordinating with the active gear 701 and multiple driven gears 702 in the adjustment assembly 7 to drive the extension and retraction of rod 12 and rod 6. Simultaneously, the auxiliary assembly 11 drives the lead screw 1103 to rotate through bevel gear 1101 and bevel gear 1102, causing the adjustment plate 9 to slide on the fixed plate 8, achieving stepless adjustment and adapting to different specifications of transparent shells. During the tooling pressing process, the hydraulic rod 4 drives each set of fixed plates 8 and adjustment plates 9 to be aligned and pressed together through the connecting plate 5. The outer surfaces of the fixed plate 8 and adjustment plate 9 are covered with Shore A25-35. The medical-grade vapor-phase silicone layer, with a pressure sensor integrated in the middle of the connecting plate 5, dynamically monitors the clamping pressure in real time, precisely avoiding problems such as excessive pressure causing shell deformation, indentation, and secondary internal stress, or insufficient pressure causing loose clamping and processing deviation. At the same time, the tooling only clamps the waste edge area of ​​the shell, completely avoiding the processing areas of the shell side wall and bottom edge. Without structural obstruction, it can complete dust-free precision trimming, rounded corner deburring, and other operations without obstacles. Finally, after high-frequency electrostatic dust removal and dust-free air drying, each piece undergoes optical full inspection for light transmittance, haze, and flatness. The final mass production produces transparent equipment shells with excellent light transmittance, low haze, no residual stress, flawless appearance, and full compliance with medical clean use standards.

[0025] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A high-transmittance vacuum forming process for a transparent shell of a medical device, characterized in that, Specifically, the following steps are included: S1. Medical-grade board selection and dust-free activation pretreatment: High-transmittance and scratch-resistant PETG composite boards are selected. Before the raw materials are put into storage, the transmittance and haze are sampled and tested. Qualified boards with transmittance ≥92% and haze ≤0.8% are selected. The boards are placed in a Class 10,000 dust-free constant temperature workshop and a double-sided low-temperature plasma activation and ultrasonic spray composite decontamination process is adopted to remove oil stains, release agents, micro dust and static electricity residues from the board surface. After treatment, the boards are sealed and left to stand for later use to prevent secondary pollution. S2. Segmented constant temperature and gentle heating: The upper and lower independent temperature-controlled infrared radiation heating system is used to heat in three stages: low temperature preheating, constant temperature uniform heating, and shaping and heat preservation. This accurately controls the overall temperature of the board, eliminates the temperature difference between the inside and outside of the board and the problem of local overheating, avoids yellowing, fogging and thermal deformation defects of transparent boards, and ensures uniform softening and stable molecular stress of the board. S3. Mirror-finish mold dustproof and mold closing positioning: Adopts a cavity mirror-polished mold with a smooth inner wall roughness. m, the mold is preheated with dust-free air blowing in advance to avoid condensation and fogging on the surface of the sheet material due to temperature difference in the mold; the sheet material is evenly clamped and positioned on all four sides by an adjustable elastic pressure frame to prevent the sheet material from shifting or loosening after heating, and to ensure the molding alignment accuracy. S4. Air pressure pre-stretching and graded negative pressure vacuum forming: First, low-pressure positive air pressure is used for pre-stretching to make the sheet evenly expand and extend, and optimize the sheet wall thickness distribution. Then, a graded negative pressure vacuuming process is used to gradually increase the vacuum degree, avoiding problems such as uneven sheet stretching, local thinning and abnormal light transmission caused by instantaneous negative pressure, so that the sheet can be completely fitted to the mold cavity for fine forming. S5. Layered water-cooled slow-release shaping: It adopts a labyrinth-style circulating water-cooling structure inside the mold, with segmented gradient cooling and a small amount of air cooling to assist uniform cooling. Unlike the traditional rapid cooling process, it effectively releases the internal forming stress of the sheet material, eliminates the problems of warping, deformation and cracking of the transparent shell in the later stage, and at the same time ensures the flatness of the shell surface and high light transmittance. S6. Aseptic Post-processing and Optical Inspection: After demolding, the molded shell is immediately placed in the tooling fixture for fitting, positioning and fixing, constraining shell displacement and micro-deformation, and avoiding deformation, uneven chamfering and surface scratches in subsequent processing. After fixing, dust-free precision trimming and rounded chamfering are performed to remove burrs and sharp edges. Then, high-frequency electrostatic dust removal and dust-free air drying are performed. Finally, each piece is subjected to optical inspection for light transmittance, haze and flatness to screen qualified transparent shell products for medical equipment.

2. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 1, characterized in that: The PETG composite board in S1 has a thickness of 1.5-3.0mm, a surface hardness of ≥3H, and a scratch resistance rating that meets the standards for medical device housings. The plasma activation treatment power is 90-130W, and the ultrasonic spraying uses purified water at low temperature with a processing speed of 0.3-0.6m / min.

3. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 1, characterized in that: The three-stage gradient heating parameters in S2 are as follows: preheating stage temperature 85-105℃, duration 4-6s; uniform heating stage temperature 120-135℃, duration 8-12s; heat preservation and shaping stage temperature 115-120℃, duration 3-5s; and overall temperature difference of the board material controlled ≤±2℃.

4. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 1, characterized in that: The pre-blowing pressure in S4 is 0.02-0.05MPa, and the pre-blowing time is 2-5s. The graded negative pressure forming is divided into three stages: low-pressure forming, high-pressure bonding, and pressure stabilization and shaping. The vacuum degree is -0.05MPa, -0.08MPa, and -0.09MPa respectively, and the total pressure holding time is 10-18s, which effectively optimizes the uniformity of the shell wall thickness and controls the overall wall thickness error within ±0.1mm.

5. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 1, characterized in that: The gradient water cooling temperatures in S5 are 38℃, 32℃, and 26℃ respectively, and the segmented cooling times are 6s, 5s, and 4s respectively. The slow-release cooling method is used to eliminate the internal stress of the sheet material, and the residual internal stress rate of the shell after molding is less than 5%.

6. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 1, characterized in that: The tooling fixture in step S6 includes an upper frame (1) and an adjusting plate (9). A lower frame (2) is installed below the upper frame (1), and a hydraulic rod (4) is provided at the bottom center of the upper frame (1). A connecting plate (5) is installed at the output end of the hydraulic rod (4), and a fixing plate (8) is distributed in a ring on the outer surface of the connecting plate (5). The adjusting plate (9) is slidably disposed on the outer surface of the fixing plate (8). An auxiliary component (11) for assisting in adjusting the length between the fixing plate (8) and the adjusting plate (9) is installed inside the fixing plate (8). The auxiliary component (11) includes a bevel gear one (1101), a bevel gear two (1102), and a lead screw (1103). The bottom of the bevel gear one (1101) is meshed with the bevel gear two (1102), and a lead screw (1103) is fixedly disposed at the center of one side of the bevel gear two (1102).

7. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 6, characterized in that: The lead screw (1103) is threadedly connected to the adjusting plate (9), and the adjusting plate (9) and the lead screw (1103) are distributed in a one-to-one correspondence.

8. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 7, characterized in that: The upper frame (1) and the lower frame (2) are both provided with length adjustment components (7) for synchronously adjusting the length between the fixed plate (8) and the adjustment plate (9). The adjustment components (7) include a drive gear (701) and a driven gear (702). The outer surface of the drive gear (701) is meshed with six sets of driven gears (702). A rod two (12) is fixedly installed in the middle of the driven gear (702). A rod one (6) is slidably installed in the middle of the rod two (12). The external shape and structure of the rod one (6) match the internal shape and structure of the rod two (12).

9. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 6, characterized in that: The upper frame (1) is provided with a drive assembly (10) for providing driving force. The drive assembly (10) includes a drive motor (1001), a drive roller (1002), a transmission roller (1003), a connecting shaft (1004), and a transmission component (1005). The output end of the drive motor (1001) is equipped with the drive roller (1002), and the outer surface of the drive roller (1002) is equipped with a transmission roller (1003) via belt drive. The middle part of the transmission roller (1003) is equipped with a connecting shaft (1004), and the bottom of the connecting shaft (1004) is equipped with a transmission component (1005).

10. The high-transmittance vacuum forming process for a transparent shell of a medical device according to claim 9, characterized in that: The transmission assembly (1005) is consistent with the transmission structure consisting of the drive roller (1002), the transmission roller (1003) and the belt. The outer surfaces of the upper frame (1) and the lower frame (2) are both fixedly equipped with mounting plates (3).

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