Method and system for automatically identifying rotation stopping plane of optical lens production mold

Abstract

The invention relates to the technical fields of optical lens manufacturing, electric digital data processing, automatic model design and the like, and provides a method and a system for automatically identifying a rotation stopping plane of an optical lens production mold. According to the method, a mold is placed on a rotatable boss through a mechanical arm, a laser displacement sensor is used for collecting mold height signals at edge measuring points, anticlockwise locating and clockwise rotating steps are judged and executed in combination with a threshold interval, a key angle is recorded, and a target angle is calculated to achieve automatic recognition of the rotation stopping plane of the mold. When the height at the target angle meets the threshold condition, the manipulator transfers the mold to the positioning base, and the main positioning air cylinder and the auxiliary positioning air cylinder drive the high-precision rotatable bearing to abut against the rotation stopping plane and the arc surface correspondingly to achieve accurate positioning. According to the method, misjudgment can be effectively avoided, the stability and repeatability of rotation stopping plane recognition are guaranteed, and the method is suitable for industrial automatic production of optical lens molds.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical fields of optical lens manufacturing, electric digital data processing, design automation model, etc., and particularly relates to a method and system for automatically identifying a rotation-stopping plane of an optical lens production mold. BACKGROUND

[0002] The optical lens production mold is usually a high-hardness, high-finish cylindrical structure, which has one or two rotation-stopping planes on the outer circular sidewall for limiting the relative rotation posture of the mold during clamping, handling or subsequent processes. After hot press forming or molding process, the mold needs to be taken out from the molding machine by an automatic unit or manually, and transferred to a positioning tool with a certain angle posture, otherwise it will cause the inconsistency between the workpiece coordinate system and the equipment coordinate system in the subsequent grinding, coating and detection processes, resulting in problems such as coupling failure of the positioning pin and the rotation-stopping plane, deviation of the coating opening angle, misalignment of the detection reference, etc., affecting the yield and cycle. To solve these problems, manual visual inspection combined with mechanical limit block can be used for rotation alignment, which relies on the experience of operators and is affected by workshop lighting, oil film and reflection glare when facing mirror-polished outer circles and rotation-stopping planes. The boundary judgment is unstable, the angle reproducibility is poor, and long-time operation is prone to scratching risk. In addition, a 2D visual recognition method can be used to extract the edge of the sidewall profile by a camera and calculate the plane normal, but the reflectivity of the optical mold outer surface is high, often causing high light saturation, mirror pseudo-edge, shadow blocking, resulting in insufficient recognition robustness of single / double plane, narrow / wide plane in different batches, and threshold drift caused by environmental changes. In addition, a contact trigger probe or a block can be used to find the plane reference, which is not sensitive to light, but it is easy to produce contact lag and lateral friction on the small rotation-stopping surface, increasing the probability of surface damage, and the trigger position is uncertain due to the existence of probe pressure, workpiece diameter tolerance, chamfer / roundness, resulting in angle calculation error accumulation. In addition to the recognition link, the existing automatic line also has deficiencies in the unified reference of “coordinate-angle-height”: it lacks a unified rectangular coordinate system centered on the rotation axis and an angle zero reset mechanism, resulting in the angle data between different stations cannot be directly reused; the recognition process often uses a “single threshold” to determine the effective measurement state, ignoring the height fluctuations caused by mold batch difference, edge chamfer and clamping micro-displacement, causing unstable judgment of entering / leaving the effective measurement area; at the same time, the recognition algorithm does not constrain the rotation angle speed and sensor sampling beat, which is easy to cause multiple solutions or jitter of recorded angle, making it difficult to ensure the uniqueness and reproducibility of R-type angle parameters (such as entering and leaving event angle) across batches. On the other hand, the existing tooling also has problems in the mechanical path of alignment and positioning. The common method is to drive four-point clamping with equal-diameter cylinders, without distinguishing the stress level of “main reference (rotation-stopping plane)” and “auxiliary reference (circular surface)”, which is easy to push the workpiece off-center along the circumference at the moment of introduction, causing small rebound or creep, resulting in inconsistency between the final positioning angle and the recognition angle.

[0003] In summary, the prior art at least has the following technical problems to be solved: (1) under the conditions of strong reflection, narrow plane and batch difference, the automatic recognition of the rotation-stopping plane is not robust enough, and the traditional visual / contact method is easily affected by the environment, geometric details and friction; (2) there is no unified coordinate system and angle zero point reference established around the rotation axis, and the record of the angle event is not reusable, resulting in poor consistency of the recognition result across stations and batches; (3) no stable "edge measurement point" is selected in geometry, and the effective measurement state is not described by "threshold interval" but by a single threshold value, so that the entering / leaving event triggering is unstable, thereby causing the angle calculation (such as calculating the alignment angle from two event angles) to be not unique or jittering; (4) the recognition and clamping are not distinguished between the main and auxiliary force paths, and there is a lack of design of rolling contact elements and force level difference, which is easy to damage the recognized angle posture during positioning. SUMMARY

[0004] In view of the above-mentioned problems in the prior art, the present application provides a method and system for automatically recognizing the rotation-stopping plane of an optical lens production mold, to realize stable, reproducible and industrialized automatic recognition and alignment of the rotation-stopping plane of the optical lens production mold.

[0005] In a first aspect, the present application provides a method for automatically recognizing the rotation-stopping plane of an optical lens production mold, comprising: For a cylindrical mold with one or two rotation-stopping planes, the mold is taken out from the mold pressing machine by a mechanical hand and placed in the center of a rotatable boss, and the current angle of the boss rotating motor is cleared; a laser displacement sensor is installed above the boss along the Z-axis direction, and an X, Y, Z rectangular coordinate system is established with the center of the boss as the origin, and the Z-axis is coaxial with the rotation axis of the boss; Move the X and Y axes so that the laser displacement sensor beam is located at the edge of the mold and meets the edge measurement point, the edge measurement point is the X coordinate of the mold center, the Y coordinate of the mold center plus the mold radius minus the preset distance, and the preset distance is the radial shrinkage of the mold; start the laser displacement sensor to collect the mold edge height H0, when H0 is in the threshold interval, enter the clockwise rotation step, otherwise enter the counterclockwise positioning step, the threshold interval is the range between the upper and lower limits of the mold height; In the counterclockwise positioning step, the boss rotating motor is driven to rotate counterclockwise until H0 enters the threshold interval and stops immediately, and then the clockwise rotation step is performed; in the clockwise rotation step, the boss rotating motor is driven to rotate clockwise, and when H0 is detected to be less than the lower limit height, the current angle R0 is recorded, and when H0 is detected to enter the threshold interval again, the current angle R1 is recorded immediately, and then the boss rotating motor is driven to rotate a target angle θt equal to (R0-R1) / 2-90°; Collecting the mold edge height H1 at the target angle θt by the laser displacement sensor, when H1 is in the threshold interval, the mold is transferred to the positionable base by the manipulator, the main positioning cylinder is extended to make two high-precision rotatable bearings abut against the rotation-stopping plane of the mold, and the auxiliary positioning cylinder is extended to make another two high-precision rotatable bearings abut against the circular arc surface of the mold, and the cylinder diameter of the main positioning cylinder is greater than that of the auxiliary positioning cylinder; when H1 is not in the threshold interval, the boss rotating motor is first rotated counterclockwise by a correction angle of 90°, and then the transferring and positioning steps are performed.

[0006] In a second aspect, the present application provides a system for automatically identifying the rotation-stopping plane of an optical lens production mold, which uses the method for automatically identifying the rotation-stopping plane of an optical lens production mold.

[0007] Compared with the prior art, the present application has the following beneficial effects: The present application provides a method and system for automatically identifying the rotation-stopping plane of an optical lens production mold. The method comprises: facing the cylindrical mold with one or two rotation-stopping planes, taking the mold out of the molding machine by a robot and placing it in the center of a rotatable boss, clearing the current angle of the boss rotating motor; installing a laser displacement sensor above the boss in the Z-axis direction, establishing an X, Y, Z orthogonal coordinate system with the center of the boss as the origin, and making the Z-axis coaxial with the rotating axis of the boss; moving the X-axis and Y-axis to make the laser displacement sensor beam at the edge of the mold and meet the edge measuring point, which is the X-coordinate of the mold center, the Y-coordinate of the mold center plus the mold radius minus the preset distance, and the preset distance is the radial shrinkage of the mold; starting the laser displacement sensor to collect the mold edge height H0, when H0 is in the threshold interval, entering the clockwise rotation step, otherwise entering the counterclockwise positioning step, the threshold interval is the range between the upper and lower limits of the mold height; in the counterclockwise positioning step, the boss rotating motor is driven to rotate counterclockwise until H0 enters the threshold interval and stops immediately, and then the clockwise rotation step is executed; in the clockwise rotation step, the boss rotating motor is driven to rotate clockwise, and when H0 is detected to be less than the lower limit, the current angle R0 is recorded, and when H0 is detected to enter the threshold interval again, the current angle R1 is recorded immediately, and then the boss rotating motor is driven to rotate a target angle θt equal to (R0-R1) / 2-90°; at the target angle θt, the laser displacement sensor collects the mold edge height H1, when H1 is in the threshold interval, the mold is transferred to a positionable base by the robot, the main positioning cylinder is extended to make two high-precision rotatable bearings abut against the rotation-stopping plane of the mold, and the auxiliary positioning cylinder is extended to make the other two high-precision rotatable bearings abut against the arc surface of the mold, and the cylinder diameter of the main positioning cylinder is greater than that of the auxiliary positioning cylinder; when H1 is not in the threshold interval, the boss rotating motor is first rotated counterclockwise by a correction angle of 90°, and then the transfer and positioning steps are executed. The present application can realize stable, reproducible and industrialized automatic identification and alignment of the rotation-stopping plane of the optical lens production mold. BRIEF DESCRIPTION OF DRAWINGS

[0008] The drawings described herein are intended to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve the purpose of explaining the present application. Some specific embodiments of the present application will be described in detail hereinafter with reference to the drawings, which are given by way of illustration, but not intended to be limiting of the present application. In the drawings, like or similar elements or parts are designated with the same reference numerals, and it is to be understood that the drawings are not necessarily to scale: Figure 1 is a flowchart of a method for automatically identifying the rotation-stopping plane of an optical lens production mold according to an embodiment of the present application; Figure 2It is a position state schematic view of the embodiment of the application when the double rotation-stopping plane 6-hole mold rotates with the edge measuring point; Figure 3 It is another position state schematic view of the embodiment of the application when the double rotation-stopping plane 6-hole mold rotates with the edge measuring point; Figure 4 It is still another position state schematic view of the embodiment of the application when the double rotation-stopping plane 6-hole mold rotates with the edge measuring point; Figure 5 It is still another position state schematic view of the embodiment of the application when the double rotation-stopping plane 6-hole mold rotates with the edge measuring point. DETAILED DESCRIPTION

[0009] In order to make the person skilled in the art better understand the application scheme, the technical scheme in the embodiment of the application will be described clearly and completely below in combination with the drawings in the embodiment of the application. All other embodiments obtained by the person skilled in the art without creative labor on the basis of the embodiments in the application shall belong to the protection scope of the application.

[0010] Referring to Figures 1-5 The embodiment of the application provides a method for automatically identifying a rotation-stopping plane of an optical lens production mold, which can be used in a system for automatically identifying the rotation-stopping plane of the optical lens production mold, and realizes stable, reproducible and industrialized automatic identification and alignment of the rotation-stopping plane of the optical lens production mold. The method comprises the following steps: S101, for a cylindrical mold with one or two rotation-stopping planes, the mold is taken out from a mold pressing machine by a mechanical hand and placed in the center of a rotatable boss, the current angle of the boss rotating motor is cleared, a laser displacement sensor is installed above the boss in the Z-axis direction, an X, Y, Z orthogonal coordinate system is established with the center of the boss as the origin, and the Z-axis is coaxial with the rotation axis of the boss; S102, the X-axis and the Y-axis are moved, so that the light beam of the laser displacement sensor is located at the edge of the mold and satisfies the edge measuring point, the edge measuring point is the X coordinate of the center of the mold in the X direction and the Y coordinate of the center of the mold in the Y direction plus the radius of the mold minus a preset distance, the preset distance is the radial shrinkage of the mold; the laser displacement sensor is started to collect the edge height H0 of the mold, when H0 is in a threshold interval, a clockwise rotation step is entered, otherwise a counterclockwise positioning step is entered, the threshold interval is the range between the upper limit height and the lower limit height of the mold; S103, driving the boss rotating motor to rotate counterclockwise in the counterclockwise positioning step until H0 enters the threshold interval and stops immediately, and then performing the clockwise rotating step; driving the boss rotating motor to rotate clockwise in the clockwise rotating step, recording the current angle as R0 when H0 is detected to be less than the lower limit height, stopping immediately and recording the current angle as R1 when H0 is detected to enter the threshold interval again, and then driving the boss rotating motor to rotate a target angle θt equal to (R0-R1) / 2-90°; S104, collecting the mold edge height H1 by the laser displacement sensor at the target angle θt, and transferring the mold to the positionable base by the manipulator when H1 is in the threshold interval, extending the main positioning cylinder to make the two high-precision rotatable bearings abut against the rotation-stopping plane of the mold, and extending the auxiliary positioning cylinder to make the other two high-precision rotatable bearings abut against the circular arc surface of the mold, and the cylinder diameter of the main positioning cylinder is greater than that of the auxiliary positioning cylinder; when H1 is not in the threshold interval, first rotating the boss rotating motor counterclockwise by a correction angle of 90°, and then performing the transferring and positioning steps.

[0011] In this embodiment, a laser displacement sensor is installed above the boss along the Z-axis direction, and an X, Y, Z rectangular coordinate system is established with the center of the boss as the origin, and the Z-axis is coaxial with the rotation axis of the boss, which can provide a unified coordinate system and angle zero point reference, avoid the problem of inconsistent recognition results across stations and batches, and realize the unity and reusability of angle measurement and height measurement in the same reference system. Move the X and Y axes so that the laser displacement sensor's light beam is at the edge of the mold and meets the edge measurement point, which is the X coordinate of the mold center, the Y coordinate of the mold center plus the mold radius minus a preset distance (e.g., 1 mm), and the preset distance is the radial shrinkage of the mold, thereby determining the trigger position through the edge measurement point, realizing the fixation of the edge measurement point geometric condition, and ensuring the stability of the entering / leaving effective measurement area determination. Start the laser displacement sensor to collect the mold edge height H0, when H0 is in the threshold interval, enter the clockwise rotation step, otherwise enter the counterclockwise positioning step, the threshold interval is the range between the upper and lower limits of the mold height, which avoids the problem of unstable determination caused by relying on a single threshold, realizes the replacement of single-point threshold with height interval, and enhances the robustness of the entering / leaving event trigger. In the clockwise rotation step, the boss rotation motor is driven to rotate clockwise, and when H0 is detected to be less than the lower limit height, the current angle R0 is recorded, and when H0 is detected to enter the threshold interval again, it is immediately stopped and the current angle R1 is recorded, and then the boss rotation motor is driven to rotate a target angle θt equal to (R0-R1) / 2-90°, thereby realizing a way to calculate the target angle based on two characteristic angle intervals, making the recognized stop plane unique and repeatable. At the target angle θt, the laser displacement sensor collects the mold edge height H1, when H1 is in the threshold interval, the mold is transferred to a positionable base by the manipulator, the main positioning cylinder is extended to make two high-precision rotatable bearings abut against the stop plane of the mold, and the auxiliary positioning cylinder is extended to make the other two high-precision rotatable bearings abut against the circular arc surface of the mold, and the cylinder diameter of the main positioning cylinder is greater than that of the auxiliary positioning cylinder, thereby distinguishing the main and auxiliary force paths, realizing the main reference guide first and the stable mechanical path with the auxiliary reference, and keeping the recognized angle consistent with the final positioning angle. When H1 is not in the threshold interval, first rotate the boss rotation motor counterclockwise by a correction angle of 90°, and then perform the transfer and positioning steps, which can avoid the problem of 180° symmetry incompatibility between single-plane and double-plane molds, and realize unified correction and compatibility in the symmetric case.

[0012] Preferably, the boss is continuously rotated counterclockwise at a fixed angular velocity under the reference of the boss rotary motor angle zero, and H0 is read in real time, H0 is compared with the set upper and lower limit heights of the mold, if H0 enters the threshold interval for the first time, the counterclockwise rotation is immediately stopped and the clockwise rotation step is entered, if H0 crosses the threshold interval and leaves again during the counterclockwise rotation, the counterclockwise rotation is continued until it enters the threshold interval again and is immediately stopped, so as to avoid misjudgment caused by the random initial angle of the mold, and the angular velocity remains unchanged during the entire positioning process to ensure the consistency of the angle criterion and the height criterion.

[0013] In the embodiment, the boss is continuously rotated counterclockwise at a fixed angular velocity under the reference of the boss rotary motor angle zero, and H0 is read in real time, H0 is compared with the set upper and lower limit heights of the mold, if H0 enters the threshold interval for the first time, the counterclockwise rotation is immediately stopped and the clockwise rotation step is entered, if H0 crosses the threshold interval and leaves again during the counterclockwise rotation, the counterclockwise rotation is continued until it enters the threshold interval again and is immediately stopped, and the angular velocity remains unchanged during the entire positioning process, so as to avoid the random initial placement angle of the mold, which causes the system to be unable to accurately determine when to enter the effective measurement area. Since the initial angle of the mold is uncontrollable, if the system does not have a consistent angular velocity and entry condition, the correct trigger point may be missed or different stop angles may be exhibited under different batches, causing the subsequent identified angle to be unstable. The scheme of the embodiment can ensure the stability and consistency of the positioning process under a unified zero reference, ensure the uniqueness of the trigger condition for entering the effective measurement area, and thus improve the reproducibility and reliability of the identified starting point.

[0014] Preferably, the laser displacement sensor beam is fixed on the edge measurement point before the clockwise rotation starts, H0 is continuously read at a uniform sampling interval during the clockwise rotation, when H0 is less than the lower limit height for the first time, the boss rotary motor angle at that time is recorded as R0 and the clockwise rotation is continued, and when H0 returns to the threshold interval again, the clockwise rotation is immediately stopped and the angle at that time is recorded as R1, wherein R0 and R1 are used together to represent the angle interval of the mold edge height curve relative to the stop plane, and the collection of R0 and R1 is completed in a monotonic process with the rotation angle as the independent variable.

[0015] In this embodiment, the laser displacement sensor beam is fixed at the edge measurement point before starting clockwise rotation, H0 is continuously read at a uniform sampling interval during clockwise rotation, and when H0 first falls below the lower limit height, the current boss rotation motor angle is recorded as R0 and clockwise rotation is continued. When H0 returns to the threshold interval again, it is immediately stopped and the current angle is recorded as R1. R0 and R1 are used together to represent the angle interval of the mold edge height curve relative to the stop plane, and the collection of R0 and R1 is a monotonic process with rotation angle as the independent variable, which can solve the problem of non-uniform sampling interval and non-unique angle triggering event. The rotation is not synchronized with the sensor sampling, which is easy to miss the actual entering / leaving boundary, resulting in angle jitter or repeated determination. The scheme of this embodiment fixes the edge measurement point and unifies the sampling interval to accurately capture the height change feature point during rotation, making the angle data of R0 and R1 unique and repeatable, thereby ensuring the reliability and accuracy of the subsequent calculation of the target angle θt.

[0016] Preferably, after obtaining R0 and R1, the target angle θt is calculated, θt=(R0-R1) / 2-90°; then only rotate to the angle position corresponding to the target angle θt through the boss rotation motor, without changing the measurement point coordinates and Z-axis installation posture of the laser displacement sensor during execution; when θt is negative, rotate in the counterclockwise direction, and when θt is positive, rotate in the clockwise direction, to unify the correspondence relationship between the angle symbol and the execution direction.

[0017] Preferably, after obtaining R0 and R1, the target angle θt is calculated, θt=(R0-R1) / 2-90°; then only rotate to the angle position corresponding to the target angle θt through the boss rotation motor, without changing the measurement point coordinates and Z-axis installation posture of the laser displacement sensor during execution; when θt is negative, rotate in the counterclockwise direction, and when θt is positive, rotate in the clockwise direction, to unify the correspondence relationship between the angle symbol and the execution direction.

[0018] Preferably, the determination of H1 is triggered only after reaching the target angle θt; if H1 does not enter the threshold interval, the boss rotation motor is instructed to rotate counterclockwise by 90° based on the current angle and the edge measurement point remains unchanged, and H1 is determined again whether it enters the threshold interval; regardless of the result of the second determination, the mechanical hand is grasped and enters the positioning step according to the predetermined posture, to be compatible with single-stop plane and double-stop plane molds.

[0019] In this embodiment, the determination of H1 is triggered only after reaching the target angle θt; if H1 does not enter the threshold interval, the boss rotating motor is directly instructed to rotate counterclockwise by 90° based on the current angle and the edge measuring point remains unchanged, and it is determined again whether H1 enters the threshold interval; regardless of the result of the second determination, the robot is instructed to grasp according to the predetermined posture and enter the positioning step, which can solve the problem of unreliable recognition when the single-stop rotating plane and the double-stop rotating plane mold exist symmetric ambiguity. For the double-stop rotating plane, two sets of symmetric solutions may appear at θt, and if no correction is made, the positioning may be incorrect. Through the step of correcting the angle by 90°, a unified recognition logic under the symmetric structure is realized, and the single-plane and double-plane molds are automatically adapted, thereby improving the universality and reliability of the system.

[0020] Preferably, the measuring point coordinates of the laser displacement sensor, the installation posture of the Z-axis, and the threshold interval formed by the upper limit height and the lower limit height remain unchanged throughout the entire recognition process, and the recording of R0 and R1 and the execution of the target angle θt and the 90° correction angle are triggered only by the angle change of the boss rotating motor, and it is specified that the readings of H0 and H1 are completed with the same measuring path and the same measuring point.

[0021] In this embodiment, the measuring point coordinates of the laser displacement sensor, the installation posture of the Z-axis, and the threshold interval formed by the upper limit height and the lower limit height remain unchanged throughout the entire recognition process, and the recording of R0 and R1 and the execution of the target angle θt and the 90° correction angle are triggered only by the angle change of the boss rotating motor, and it is specified that the readings of H0 and H1 are completed with the same measuring path and the same measuring point, which can solve the problem of inconsistent results caused by measuring point position drift, inconsistent threshold determination, or change of sampling path. If the measuring point changes or different thresholds are used at different stages, it is easy to cause inconsistent height determination, which affects angle calculation. The scheme of this embodiment unifies all constraints to ensure consistency of "coordinates-angle-height" throughout the entire recognition process, ensuring that data at different stages can be directly compared, improving the repeatability of the results and the consistency across batches.

[0022] Preferably, the threshold interval is pre-set according to the target mold specification, and the determination of H0 and H1, the stop in the counterclockwise positioning step, and the stop in the clockwise rotating step all use the threshold interval as the unified scale. When H0 is within the threshold interval, it indicates that the mold edge aligned by the laser beam is in an effective measuring posture. When H0 is less than the lower limit height, it indicates that the mold edge profile enters the low position area and serves as the trigger condition for recording R0. When H0 reenters the threshold interval, it indicates that it returns to the effective posture and serves as the trigger condition for recording R1.

[0023] In the embodiment, the threshold interval is preset according to the target mold specification, and the threshold interval is a unified scale for the determination of H0 and H1, the stop in the counterclockwise positioning step, and the stop in the clockwise rotating step. When H0 is in the threshold interval, it indicates that the mold edge aligned by the laser beam is in an effective measurement posture. When H0 is less than the lower limit height, it indicates that the mold edge profile enters a low position area and serves as a trigger condition for recording R0. When H0 reenters the threshold interval, it indicates that it returns to the effective posture and serves as a trigger condition for recording R1. The problem of inconsistent determination conditions can be solved. If different criteria are used in different steps, inconsistent results will be caused. The scheme of the embodiment realizes the consistency of the trigger conditions by unifying the threshold interval as the basis for all determinations, ensures the collection logic of R0 and R1 to be clear and reliable, and thus stabilizes the target angle calculation and makes it controllable.

[0024] Preferably, after the H1 confirmation is completed or the 90° correction is completed, the manipulator grasps the mold and places it on a base capable of positioning the mold. The main positioning cylinder is controlled to extend so that two high-precision rotatable bearings form a line-plane contact with the rotation-stopping plane of the mold and provide a main clamping force. Then, the auxiliary positioning cylinder is controlled to extend so that the other two high-precision rotatable bearings form a point-line contact with the circular arc surface of the mold and provide an auxiliary clamping force. It is specified that the cylinder diameter of the main positioning cylinder is greater than that of the auxiliary positioning cylinder so that the main clamping force is greater than the auxiliary clamping force. Thus, when there is an initial angular deviation of the mold, the main positioning is used to guide first, and then the auxiliary positioning is used to stabilize circumferentially.

[0025] In the embodiment, after the H1 confirmation is completed or the 90° correction is completed, the manipulator grasps the mold and places it on a base capable of positioning the mold. The main positioning cylinder is controlled to extend so that two high-precision rotatable bearings form a line-plane contact with the rotation-stopping plane of the mold and provide a main clamping force. Then, the auxiliary positioning cylinder is controlled to extend so that the other two high-precision rotatable bearings form a point-line contact with the circular arc surface of the mold and provide an auxiliary clamping force. It is specified that the cylinder diameter of the main positioning cylinder is greater than that of the auxiliary positioning cylinder so that the main clamping force is greater than the auxiliary clamping force. Thus, when there is an initial angular deviation of the mold, the main positioning is used to guide first, and then the auxiliary positioning is used to stabilize circumferentially.

[0026] Preferably, the rotation shafts of the two bearings for the rotation-stopping plane are parallel to the Z axis and allow the outer circular raceway to rotate, so as to allow a small amount of rolling along the rotation-stopping plane during the advancement of the main positioning cylinder without introducing significant frictional resistance. The rotation shafts of the two bearings for the circular arc surface are also parallel to the Z axis and allow adaptive rolling along the circular arc generatrix direction during the advancement of the auxiliary positioning cylinder, so as to adapt to the local roundness and cylindricity deviation of the mold cylindrical surface.

[0027] In the embodiment, the rotation shafts of the two bearings for the rotation-stopping plane are parallel to the Z axis and allow self-rotation of the outer circular raceway to allow micro-rolling along the rotation-stopping plane during the advancement of the main positioning cylinder without introducing significant frictional resistance; the rotation shafts of the two bearings for the circular arc surface are also parallel to the Z axis and allow adaptive rolling along the direction of the circular arc generatrix during the advancement of the auxiliary positioning cylinder to adapt to the local roundness and cylindricity deviation of the mold cylindrical surface, which can solve the technical problems of large frictional force in rigid clamping and easy damage to the surface. The scheme of the embodiment reduces the frictional force in the clamping process through the rolling contact of the rotatable bearings, avoids scratching of the mold surface, and at the same time allows adaptive compensation of the roundness and cylindricity deviation. The scheme realizes the reduction of stress concentration and surface damage while ensuring the clamping force, and improves the service life of the mold and the reliability of the tooling.

[0028] Preferably, when the mold has two rotation-stopping planes, the two high-precision rotatable bearings corresponding to the main positioning cylinder abut against the two rotation-stopping planes respectively; when the mold has only one rotation-stopping plane, the two high-precision rotatable bearings of the main positioning cylinder jointly abut against the rotation-stopping plane and provide a counterforce with the two high-precision rotatable bearings of the auxiliary positioning cylinder abutting against the circular arc surface.

[0029] In the embodiment, when the mold has two rotation-stopping planes, the two high-precision rotatable bearings corresponding to the main positioning cylinder abut against the two rotation-stopping planes respectively; when the mold has only one rotation-stopping plane, the two high-precision rotatable bearings of the main positioning cylinder jointly abut against the rotation-stopping plane and provide a counterforce with the two high-precision rotatable bearings of the auxiliary positioning cylinder abutting against the circular arc surface, which can solve the problem of incompatibility of single-plane molds and double-plane molds. In traditional designs, tooling is often designed for a single type of mold, lacking universality. The scheme of the embodiment defines two clamping strategies under the same positioning structure, realizes compatibility with different mold structures, allows the production line to adapt to different mold types without replacing the fixture, and thus improves the flexibility and universality of the automated production line.

[0030] Preferably, the angle zeroing operation is performed only after the robot first places the mold in the center of the boss and completes the concentricity with the shaft, and then all angle events are recorded under the same zero reference, including the stop angle when entering the threshold interval counterclockwise, R0 when H0 is less than the lower limit height during clockwise rotation, R1 when H0 returns to the threshold interval during clockwise rotation, and the execution of the target angle θt and the 90° correction angle. Any case of taking down and replaying in the middle needs to be re-zeroed and executed again.

[0031] In this embodiment, the angle zeroing operation is only performed when the robot first places the mold in the center of the boss and completes the concentricity of the shaft, and then all angle events are recorded under the same zero reference, including the stop angle when entering the threshold interval counterclockwise, R0 when H0 is less than the lower limit height during clockwise rotation, R1 when H0 returns to the threshold interval during clockwise rotation, and the execution of the target angle θt and the 90° correction angle. Any intermediate removal and playback situation needs to be re-zeroed and executed again, which can solve the problem of untraceable recognition data caused by angle reference drift. If the workpiece is removed or the reference is not uniform during the process, it will cause confusion in angle determination. The scheme of the embodiment can realize that all angle events are based on a unified reference, thereby ensuring the consistency and traceability of the angle data chain and improving the data reliability across batches and stations.

[0032] It should be noted that the mold pressing machine refers to a glass aspheric lens forming machine, which is a machine for one-time forming of high-precision aspheric lenses by high-temperature pressing of softened glass under oxygen-free conditions. The automatic loader automatically takes out the lens inside the mold formed by the mold pressing machine, places it in a predetermined position, and then puts the preform into the mold. The mold is then conveyed into the mold pressing machine. Generally, the mold shape has a cylindrical body and a square body, and a mold has 1, 2, 3, 4, 5, 6, 8, 9, 10 holes, i.e., a single pressing of multiple lenses is achieved by combining the mold. In the process of ultra-precision machining, in order to prevent the mold from rotating or displacing in the clamp, the mold is designed to have one or two rotation-stopping planes. In order to fix the position of the mold by the automatic loader and accurately take out the lens inside the mold, the above embodiment proposes a method for automatically identifying the rotation-stopping plane of the mold. Exemplarily, in the method for automatically identifying the rotation-stopping plane of the mold, the following No. 1-No. 9 implementation descriptions can be specifically included: 1. After the mold (cylindrical body) comes out of the mold pressing machine, the angle of the mold is random and indefinite.

[0033] 2. The robot places the mold in the center of a rotatable boss, and the current angle of the boss rotation motor is zeroed.

[0034] 3. A laser displacement sensor is installed on the Z-axis.

[0035] 4. Move the X and Y axes to move the laser displacement sensor beam to the edge of the mold, X-axis coordinate = mold center, Y-axis coordinate = mold center + mold radius - 1mm.

[0036] 5. Laser displacement sensor starts reading mold height H0, H0 is in the range of the upper and lower limit of the set mold height, then execute No. 6, otherwise execute No. 6-1. 6-1. The boss rotating motor starts counterclockwise rotation, when H0 is in the range of the upper and lower limit of the set mold height, the boss rotating motor stops immediately. Execute No. 6.

[0037] 6. The boss rotating motor starts clockwise rotation, when rotating to H0 is less than the lower limit of the set mold height, record the current angle R0 of the rotating boss motor, when rotating to H0 is in the range of the upper and lower limit of the set mold height, the boss rotating motor stops immediately, record the current angle R1 of the rotating boss motor.

[0038] 7. Execute the boss rotating motor rotation, rotation angle = (R0 - R1) / 2 - 90°.

[0039] 8. Laser displacement sensor starts reading mold height H1, H1 is in the range of the upper and lower limit of the set mold height, then execute No. 9. Otherwise execute the boss rotating motor counterclockwise rotation 90° and then execute No. 9.

[0040] 9. The robot puts the mold on a base that can position the mold, the main positioning cylinder extends, the two high-precision rotatable bearings push against the rotation-stopping plane of the mold, then the auxiliary positioning cylinder extends, the two high-precision rotatable bearings push against the arc surface of the mold, the cylinder diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder, so even if the mold has a certain angular deviation before positioning, the mold can be automatically aligned.

[0041] It should be noted that the above embodiments are only the preferred specific implementation of the present application, the protection scope of the present application is not limited to this, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, all should be covered in the protection scope of the present application, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for automatically identifying the anti-rotation plane of an optical lens manufacturing mold, characterized in that, include: For a cylindrical mold with one or two anti-rotation planes, a robot arm removes the mold from the molding machine and places it at the center of a rotatable boss, and sets the current angle of the boss's rotation motor to zero; a laser displacement sensor is installed above the boss along the Z-axis, and an X, Y, Z rectangular coordinate system is established with the center of the boss as the origin, and the Z-axis is made coaxial with the rotation axis of the boss. Move the X and Y axes so that the laser displacement sensor beam is located at the edge of the mold and meets the edge measurement point. The edge measurement point is the X coordinate of the mold center in the X direction and the Y coordinate of the mold center in the Y direction plus the mold radius minus a preset distance. The preset distance is the radial inward shrinkage of the mold. Start the laser displacement sensor to collect the mold edge height H0. When H0 is within the threshold range, enter the clockwise rotation step; otherwise, enter the counterclockwise positioning step. The threshold range is the range between the upper limit height and the lower limit height of the mold. In the counterclockwise positioning step, the boss rotary motor is driven to rotate counterclockwise until H0 enters the threshold range and stops immediately. Then, the clockwise rotation step is performed. In the clockwise rotation step, the boss rotary motor is driven to rotate clockwise. When H0 is detected to be less than the lower limit height, the current angle is recorded as R0. When H0 is detected to enter the threshold range again, the current angle is stopped immediately and recorded as R1. Then, the boss rotary motor is driven to rotate by a target angle θt equal to (R0-R1) / 2-90°. At the target angle θt, a laser displacement sensor collects the mold edge height H1. When H1 is within the threshold range, a robot transfers the mold to a positionable base. The main positioning cylinder extends to make two high-precision rotatable bearings abut against the mold's anti-rotation plane, and the auxiliary positioning cylinder extends to make two other high-precision rotatable bearings abut against the mold's arc surface. The diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder. When H1 is not within the threshold range, the boss rotary motor is first rotated counterclockwise by 90° to correct the angle before the transfer and positioning steps are performed.

2. The method according to claim 1, characterized in that, With the angle of the boss rotary motor zeroed, the boss is continuously rotated counterclockwise at a fixed angular velocity, and H0 is read in real time. H0 is compared with the set upper and lower limits of the mold height. If H0 enters the threshold range for the first time, the counterclockwise rotation is stopped immediately and the clockwise rotation step is started. If H0 crosses the threshold range and leaves again during the counterclockwise rotation, the counterclockwise rotation continues until it enters the threshold range again and stops immediately to avoid misjudgment caused by the random initial angle of the mold. The angular velocity remains constant throughout the positioning process to ensure the consistency of the angle criterion and the height criterion.

3. The method according to claim 1, characterized in that, Before starting clockwise rotation, the laser displacement sensor beam is kept fixed at the edge measuring point. During the clockwise rotation, H0 is continuously read at a uniform sampling rate. When H0 is less than the lower limit height for the first time, the angle of the boss rotation motor at that time is recorded as R0 and the clockwise rotation continues. When H0 returns to the threshold range again, it is stopped immediately and the angle at that time is recorded as R1. R0 and R1 are used together to characterize the angle range of the mold edge height curve relative to the stop plane. The acquisition of R0 and R1 is completed in a monotonic process with the rotation angle as the independent variable.

4. The method according to claim 1, characterized in that, After obtaining R0 and R1, the target angle θt is calculated as θt = (R0 - R1) / 2 - 90°. Then, the platform is rotated to the angular position corresponding to the target angle θt by a rotary motor. During the execution, the coordinates of the measuring point of the laser displacement sensor and the installation posture of the Z-axis are not changed. When θt is negative, the rotation is counterclockwise, and when θt is positive, the rotation is clockwise to unify the correspondence between the angle sign and the execution direction.

5. The method according to claim 1, characterized in that, The determination of H1 is triggered only after the target angle θt is reached; if H1 does not enter the threshold range, the boss rotary motor is directly instructed to rotate 90° counterclockwise based on the current angle while keeping the edge measuring point unchanged, and H1 is determined again to see if it enters the threshold range; regardless of the result of the second determination, the robot is grasped by the robot in a predetermined posture and enters the positioning step to be compatible with single anti-rotation plane and double anti-rotation plane molds.

6. The method according to claim 1, characterized in that, Throughout the entire recognition process, the coordinates of the laser displacement sensor's measuring point remain unchanged, the Z-axis mounting posture remains unchanged, and the threshold range formed by the upper and lower limits of the height remains unchanged. The recording of R0 and R1, the execution of the target angle θt, and the 90° correction angle are triggered only by the angle change of the boss rotary motor. At the same time, it is stipulated that the readings of H0 and H1 are completed using the same measurement path and the same measuring point.

7. The method according to claim 1, characterized in that, The threshold range is preset according to the target mold specifications. The determination of H0 and H1, the stopping of the counterclockwise positioning step, and the stopping of the clockwise rotation step are all based on the threshold range as a unified scale. When H0 is within the threshold range, it means that the mold edge aligned with the laser beam is in an effective measurement posture. When H0 is less than the lower limit height, it means that the mold edge contour has entered the low position area and serves as the trigger condition for recording R0. When H0 re-enters the threshold range, it means that it has returned to an effective posture and serves as the trigger condition for recording R1.

8. The method according to claim 1, characterized in that, After H1 confirmation or 90° correction is completed, the robot arm grasps the mold and places it on a base that can position the mold. The main positioning cylinder is extended to make two high-precision rotatable bearings make surface-to-line contact with the anti-rotation plane of the mold and provide the main clamping force. Then, the auxiliary positioning cylinder is extended to make two other high-precision rotatable bearings make point-to-line contact with the arc surface of the mold and provide auxiliary clamping force. It is specified that the cylinder diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder so that the main clamping force is greater than the auxiliary clamping force. Thus, when there is an initial angular deviation in the mold, the main positioning first achieves the correction, and then the auxiliary positioning achieves circumferential stability.

9. The method according to claim 8, characterized in that, The two bearings used for the anti-rotation plane have their shafts parallel to the Z-axis and their outer raceways are rotatable, so that a small amount of rolling along the anti-rotation plane is allowed during the advancement of the main positioning cylinder without introducing significant frictional resistance. The shafts of the two bearings used for the arc surface are also parallel to the Z-axis and are allowed to generate adaptive rolling along the arc generatrix direction during the advancement of the secondary positioning cylinder, so as to adapt to the local roundness and cylindricity deviation of the mold cylindrical surface.

10. A system for automatically identifying the anti-rotation plane of an optical lens manufacturing mold, characterized in that, The system for automatically identifying the anti-rotation plane of an optical lens production mold uses the method for automatically identifying the anti-rotation plane of an optical lens production mold as described in any one of claims 1-9.

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