Device and method suitable for demolding and monitoring curved ultra-smooth surface lens

Abstract

The invention discloses a device and a method suitable for demolding and monitoring a curved ultra-smooth surface lens. The device comprises a vacuum chuck unit (with a built-in pressure sensor), a clamping and lifting device, a holding disc, a heating and supporting base and a mandrel mold. The process comprises the following steps: adjusting the clamping device to complete lens placement and coaxial positioning; the mandrel is heated to a set temperature and then placed in a normal temperature environment, and after the mandrel is cooled to a target low temperature, a demolding gap is generated by utilizing a thermal expansion coefficient difference between the mandrel and the lens. Starting the vacuum chuck in stages, performing low-vacuum stable adsorption, and then adjusting the vacuum degree according to the reading of the pressure sensor; and the real-time pressure and the effective contact area are converted into demolding force F, the peak value, the slope and the pulsation of an F-t curve are recorded and monitored, whether demolding is smooth or not is recognized, and accordingly pressure limiting, slow rising or resetting is conducted to correct deviation. After confirming that a demoulding gap and adsorption are stable, carrying out micro-step lifting to implement separation; and after demolding is completed and the lens is stably adsorbed, the vacuum suction cup is controlled to be lifted to a safe height, and finally the lens is manually transferred to a designated position.

Description

Technical Field

[0001] This invention relates to the field of precision optical component manufacturing, and in particular to a special device that integrates a cold shrink mandrel for demolding ultra-smooth surface lenses (hereinafter referred to as "lenses") with a vacuum lifting system by utilizing the principle of thermal expansion and contraction, as well as a method for non-destructive, high-precision demolding and lifting of lenses using this device. Background Technology

[0002] Ultra-smooth surface lenses are precision optical components, typically consisting of a thin film layer with high reflectivity (such as gold or platinum) coated on a mandrel, and a complex curved surface shape (such as a parabola or hyperboloid). After the manufacturing process is complete, they need to be precisely demolded from the manufacturing tools (such as mandrels or molds) for subsequent inspection, coating repair, or installation.

[0003] Traditional demolding methods present numerous challenges, including a high risk of surface damage. Mechanical demolding fixtures can easily scratch or crush the lens surface; conventional thermal expansion and contraction demolding (such as heating the mold) may cause lens deformation or cracking due to uneven stress, especially when there is a significant difference in the coefficients of thermal expansion between the lens and mold materials. Repeatability is difficult to guarantee: manual or semi-automatic operations struggle to achieve high-precision repeatability. Thermal stress issues: forced cooling or heating can cause internal stress in the lens, affecting its optical performance or causing damage.

[0004] Invention Patent Content

[0005] This invention provides a demolding and handling device and method for ultra-smooth surface lenses that utilizes the principle of thermal expansion and contraction, featuring a relatively simple structure, low cost, stable demolding effect, and high positioning accuracy. The device achieves precise demolding by heating the mandrel and then allowing it to cool to room temperature, leveraging the difference in thermal expansion coefficients between the lens and mandrel materials. The pressure changes between the suction cup and the lens are observed, monitoring the entire demolding process. Combined with a vacuum suction cup, it achieves stable and damage-free handling.

[0006] The present invention relates to a device and method for demolding and monitoring curved ultra-smooth surface lenses, comprising an integrated vacuum suction cup unit, a pressure sensor, a clamping and lifting device, a holding plate, a heated support base, and a mandrel mold.

[0007] The integrated vacuum suction cup unit includes eight VB-type vacuum suction cups fixedly arranged on the side of the spindle assembly. The VB-type vacuum suction cups have a structure of soft pads (such as silicone or polyurethane) and rigid support plates, ensuring that negative pressure is evenly distributed to the non-optical edge areas of the lens or pre-designed dedicated suction areas, preventing localized overload damage. The number, shape, and layout of the suction cups are optimized according to the lens structure and weight to improve suction stability and resistance to off-center loading.

[0008] The sensing unit includes a pressure sensor: used to monitor the pressure change between the lens and the mandrel, to determine whether the mandrel and the lens have completely separated before proceeding to the next lifting operation. It is integrated on the suction cup assembly to monitor the pressure change between the suction cup and the lens in real time, monitor any abnormal pressure changes, and ensure overall monitoring of pressure changes throughout the entire demolding process.

[0009] Compared with the prior art, this invention patent has the following beneficial effects:

[0010] 1. This patent can reduce the risk of damage to the optical surface by using a cold shrink mandrel to create a demolding gap and using a VB-type soft pad suction cup to support and lift the lens at the non-optical edge, avoiding direct mechanical contact or pressure on the optical surface of the lens, and greatly reducing the risk of scratches, indentations and coating peeling.

[0011] 2. This patent allows for precise monitoring of the demolding gap. By using mandrel temperature to generate calculable shrinkage, combined with sensors or temperature criteria, the demolding gap becomes predictable and repeatable, rather than relying on manual intervention, thus ensuring process consistency.

[0012] 3. This invention is highly adaptable and functional. It can infer the demolding state by detecting the pressure change between the lens and the vacuum suction cup, and monitor the pressure change of the suction cup in real time to avoid damaging the lens. It is compatible with different lens materials and sizes. By selecting the mandrel material, suction cup layout and number, this method can be parametrically adjusted for different materials (fused silica, silicon, metal, etc.) and different lens sizes, and has good scalability.

[0013] Figure 1 This is a schematic diagram of the structure of the device in this invention patent;

[0014] Figure 2 This is a schematic diagram of the vacuum suction cup of this invention patent;

[0015] Figure 3 This is a flowchart of the method of this invention patent;

[0016] Figure 4 This is a simulation diagram of the suction cup force resisting the adsorption force of this invention patent.

[0017] Figure 5 This is a simulation diagram of the suction cup for lens shape retention in this invention patent.

[0018] The components include: 1. Clamping and lifting device; 1-1. Clamping guide rail; 1-2. Vacuum suction cup; 1-3. Holding plate; 2. Mandrel mold; 3. Heated support base; 4. Pressure sensor; 5. Silicone layer of vacuum suction cup. Detailed Implementation

[0019] To better understand the purpose, structure, and function of this invention, the following detailed description of the invention is provided in conjunction with the accompanying drawings.

[0020] A device and method for demolding and monitoring curved ultra-smooth surface lenses, compatible with different lens materials and sizes, is a high-precision and high-efficiency device achieved by selecting the mandrel material, suction cup layout and quantity.

[0021] like Figure 1 As shown, a device and method for demolding and monitoring of curved, ultra-smooth surface lenses are disclosed.

[0022] Includes a clamping and lifting device 1; a mandrel mold 2; a heated support base 3; and a pressure sensor 4.

[0023] Adjust the clamping and lifting device 1 to complete the lens placement and positioning. Carefully place the mandrel mold 2 to be demolded on the heated support base 3, ensuring its optical surface is facing correctly. Initial positioning is achieved through the initial adsorption and mechanical clamping of the vacuum suction cups 1-2, ensuring concentricity and coaxiality with the support base 3. The heated support base 3 is activated to continuously heat the mandrel mold 2. After reaching the specified temperature, allow it to cool to room temperature for a period of time to allow the mandrel to cool and shrink. To ensure accurate subsequent judgment, the pressure sensor 4 is first zero-point calibrated to establish a baseline. When the mandrel temperature reaches the preset target low temperature value, the difference in thermal expansion coefficients between the lens and mandrel materials causes significant cold contraction of the mandrel, creating a sufficient demolding gap between the lens and the mandrel. After confirming the demolding gap, the vacuum suction cups 1-2 are activated, initially connecting to a low vacuum to complete the initial adsorption of the lens. The low vacuum stage is used for stability checks: the pressure sensor 4 continuously monitors the pressure changes between the lens, mandrel 2, and suction cups 1-2, observing whether the pressure fluctuations are within the allowable range. The system automatically judges whether the adsorption is stable, avoiding localized stretching due to a single high negative pressure. Based on the confirmation of the demolding gap and the stability of adsorption, the negative pressure is gradually increased and micro-step lifting begins. The real-time reading of pressure sensor 4 and the effective adsorption area are converted into demolding force F, and the F-t curve is recorded. The peak value, slope, and pulsation characteristics of the demolding force are monitored online to achieve full-process monitoring of the demolding force. The demolding effect is judged based on the changes in pressure / demolding force: if F rises steadily in the initial stage of lifting and then drops significantly and tends to a stable low value, demolding is considered successful; if F continues to rise or shows sawtooth pulsation, there may be poor demolding or mold jamming; if F is below the lower limit and adsorption leakage is obvious, there may be insufficient adsorption or uneven force, and it is necessary to pause and reset the low vacuum to re-stabilize. When abnormalities occur, correction is performed by deceleration, pressure holding, slight retraction, and micro-step lifting again to ensure that no sudden load is applied to the lens. In addition to real-time monitoring of the demolding force through the F-t curve, the demolding force can also be precisely controlled by arranging pressure sensors inside the vacuum suction cup to collect and output the cavity pressure value in real time. The system uses this value as the basis for determining the internal pressure of the suction cup: when there is a deviation between the measured actual pressure and the target pressure, the control unit adjusts the vacuum actuator (such as a proportional pressure regulating valve, throttle valve, or bypass solenoid valve) connected to the suction cup according to the magnitude and trend of the deviation, so as to change the vacuum degree inside the suction cup. Through continuous and precise adjustment of the vacuum degree, the cavity pressure gradually approaches and stabilizes at the preset target, thereby achieving precise control of the internal pressure of the suction cup. In terms of multi-point gripping, a collaborative gripping strategy with multiple contact points is formed by vacuum suction cups 1-2 and mechanical clamping: symmetrical force and graded negative pressure distribution are adopted during the lifting process to avoid single-point pulling; when the pressure sensor 4 detects force deviation (manifested as a local sudden increase or asymmetrical pulsation of the F curve), the lifting speed and negative pressure gradient are adjusted first to balance the force, ensuring that the force is evenly distributed among multiple contact points and reducing local strain in thin-walled areas.To achieve minimal thin-wall deformation, the entire process employs a low-acceleration, short-stroke micro-step-pause-re-micro-step lifting rhythm, controlling the force gradient to match the peak value. Simultaneously, the uniformity of the temperature difference between the mandrel and the lens is maintained to reduce warping caused by uneven thermal stress. The peak value of the demolding force and its upward slope over time are used as proxy indicators of thin-wall deformation: when the peak value is controlled and the curve is smooth without high-frequency pulsations, the risk of thin-wall deformation is considered low; if abnormal slopes or repeated peak values ​​occur, the process is paused, low vacuum pressure is maintained, and the isothermal time is extended until the stress relaxes before continuing lifting. After the lens is stably adsorbed, the clamping and lifting device 1 controls the vacuum suction cups 1-2 to slowly and steadily lift the lens to a safe height, where it is manually removed and transferred to a safe position. The entire process relies on real-time data from the pressure sensor 4 and predetermined thresholds for closed-loop monitoring: on the one hand, this enables precise monitoring and control of the demolding force and effect assessment; on the other hand, the thin-wall deformation is controlled to a minimum through a multi-point gripping uniform force strategy, thus ensuring a smooth and stable demolding process with minimal impact on the lens morphology and optical performance.

[0024] like Figure 2 As shown, a device and method for demolding and monitoring of curved, ultra-smooth surface lenses are disclosed.

[0025] The vacuum suction cup with an integrated pressure sensor is the core component for achieving "measurable, controllable, and verifiable" vacuum adsorption. It directly measures the actual pressure within the suction cup cavity, serving as the sole reliable feedback quantity for vacuum level. This drives valve control or pump speed to form a closed-loop pressure control system: automatically adjusting based on the deviation between the target pressure and the real-time pressure, ensuring rapid establishment, smooth convergence, and long-term stability of the vacuum within the cavity within the set range, avoiding overshoot and fluctuations. The sensor also supports zero-point and data recording, ensuring consistency and traceability for each adsorption process. The introduction of this sensor directly enhances the "shape-preserving" capability of the lens. Surface contact adsorption requires the formation of a nearly uniform load distribution within the contact area. The high-resolution feedback provided by the sensor allows for precise setting and gradual increase of negative pressure, reducing instantaneous impact and local peak stress, suppressing warping and higher-order distortion, thereby translating the shape-preserving advantages in simulation into implementable engineering effects. Combined with the known effective contact area, the system can also convert pressure into adsorption force in real time, achieving force control of a single suction cup, as well as load distribution and amplitude limiting when multiple suction cups work together, avoiding overload or insufficient adsorption at individual points. In terms of monitoring and safety, pressure sensors are used to identify anomalies such as leaks, poor sealing, insufficient power supply, or channel blockage. Diagnosis is achieved through pressure build-up speed and fluctuation characteristics. Once tolerances are exceeded, the system can immediately limit pressure, release pressure, or trigger an alarm to protect the lens and equipment. Simultaneously, the sensor enables the process to adapt to external disturbances, such as ambient temperature fluctuations or minor workpiece shape differences, which can be compensated through closed-loop to maintain the target vacuum and force distribution. Overall, the integrated pressure sensor upgrades the vacuum chuck from an "open-loop empirical setting" to a "closed-loop controllable process," enabling uniform load distribution for surface contact adsorption and lens shape retention requirements, thus improving reliability.

[0026] The pressure sensor measures and continuously outputs the suction cup cavity pressure in real time. This serves as the basis for determining whether the current pressure has reached the target, whether the deviation exceeds the limit, and for identifying conditions such as leakage or insufficient power supply. It is also a closed-loop control signal. As a control feedback signal, it is compared with the target pressure to drive the valve to regulate the vacuum level, achieving precise closed-loop pressure control.

[0027] like Figure 3 As shown, a device and method for demolding and monitoring of curved, ultra-smooth surface lenses are disclosed.

[0028] Includes the following steps:

[0029] S1. Adjust the clamping and lifting device to make the mandrel and the support base concentric and coaxial.

[0030] S2. Activate the heating support base, and when it reaches the specified temperature, allow it to cool to room temperature, while observing the gap between the spindle and the lens.

[0031] S3. Activate the vacuum suction cup to initially adsorb the lens.

[0032] S4. Observe the sensor readings. The pressure sensor detects the pressure throughout the demolding process. Compare and analyze the relationship between the pressure change and the curves established by various data to infer the demolding process. Monitor the demolding force to ensure the demolding process is safe and reliable.

[0033] S5. Begin demolding.

[0034] S6. Start the clamping and lifting device. After the demolding process is completed and the lens is adsorbed, control the vacuum suction cup to slowly lift the lens.

[0035] S7. Transfer lens.

[0036] like Figure 4 , 5 As shown, a device and method for demolding and monitoring ultra-smooth curved surface lenses are presented. Simulation results show that when the force pattern between the suction cup and the lens is optimized from point contact to surface contact, the concentrated force is expanded into a distributed force. The contact pressure cloud map changes from a high-gradient peak to a more uniform plateau or gentle slope distribution, and the stress concentration at the edges is weakened. The adsorption load is continuously distributed in the contact area, the peak stress is significantly reduced, the stress gradient is gentler, and the local deflection and distortion of the lens surface are effectively suppressed. This indicates that a vacuum suction cup using surface contact can provide stable "shape-preserving" constraints and support for the lens, and its shape-preserving effect is achievable.

Claims

1. A device and method for demolding and monitoring curved ultra-smooth surface lenses, characterized in that: It includes a clamping and lifting device 1, a clamping guide rail 1-1, a vacuum suction cup 1-2, a retainer 1-3, a mandrel mold 2, a heated support base 3, and a pressure sensor 4.

2. The device and method for demolding and monitoring curved ultra-smooth surface lenses according to claim 1, characterized in that: The parameters of the clamping device 1 are adjusted, and initial positioning is achieved through the initial adsorption and mechanical clamping of the vacuum suction cups 1-2, so as to realize the coaxial alignment of the lens and the positioning mandrel and ensure that its optical surface is facing correctly. The heating support base 3 is activated to continuously heat the mandrel mold 2 to the specified temperature and then let it cool to room temperature to cool the mandrel down, and the gap between the mandrel and the lens is automatically determined.

3. The device and method for demolding and monitoring curved ultra-smooth surface lenses according to claim 2, characterized in that: A staged vacuum start-up strategy is adopted. The vacuum level is fed back by a vacuum pressure sensor, and pressure sensor 4 monitors the pressure throughout the demolding process. The real-time reading of pressure sensor 4 is converted into a demolding force F based on the effective adsorption area, and the F-t curve is recorded. The peak value, slope, and pulsation characteristics of the demolding force are monitored online to achieve full-process monitoring of the demolding force. Alternatively, a pressure sensor can be placed inside the vacuum suction cup to collect and output the cavity pressure value in real time. The system uses this value as the basis for determining the internal pressure of the suction cup and changes the vacuum level inside the suction cup accordingly. Through continuous and precise adjustment of the vacuum level, the cavity pressure gradually approaches and stabilizes at the preset target, thereby achieving precise control of the internal pressure of the suction cup.

4. The apparatus and method for demolding and monitoring curved ultra-smooth surface lenses according to claim 3, characterized in that: Demolding begins. When the mandrel cools to the preset target low temperature, it shrinks significantly due to the difference in thermal expansion coefficients between the mandrel and lens materials. At this point, because of the difference in thermal expansion coefficients between the lens and the mandrel mold, a sufficiently large demolding gap is formed between the lens and the shrunken mandrel. During the cooling of the mandrel or after reaching the target temperature, pressure sensor 4 measures minute pressure changes of the lens relative to the mandrel. When a force offset is detected (manifested as a local sudden increase or asymmetrical pulsation in the F-curve), the lifting speed and negative pressure gradient are adjusted first to achieve equilibrium, ensuring that the force is evenly distributed among multiple contact points, thereby confirming the formation of the overall demolding gap.

5. The apparatus and method for demolding and monitoring of curved ultra-smooth surface lenses according to claim 4, characterized in that: Start the clamping and lifting device 1, and control the vacuum suction cups 1-2 to slowly lift the lens. Employ a multi-point gripping method, utilizing the vacuum suction cups 1-2 and mechanical clamping to form a multi-contact point collaborative gripping strategy: The lifting process employs symmetrical force application and graded negative pressure distribution to avoid single-point pulling. The lens is then manually moved to a safe position.

6. A device and method for demolding and monitoring curved ultra-smooth surface lenses according to any one of claims 1 to 6, characterized in that: Includes the following steps: S1. Adjust the clamping and lifting device 1 S2. Start heating the support base 3 S3. Activate vacuum suction cups 1-2 S4. Observe the sensor readings. S5. Begin demolding. S6. Activate the clamping and lifting device 1 S7. Transfer lens.

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