A method for processing an aspherical optical element

Abstract

The application discloses a kind of aspheric optical element processing method, it is characterized in that include following steps: step one, establish processing surface quality and processing time database;Step two, start optical element processing, when workpiece I completes grinding and detection, wait for polishing or complete a round of polishing and detection, then wait for compensation polishing, judge polishing machine tool processing state;Step three (a), each station optimal time matching: step three (b), each station shortest time matching: step four, adjust workpiece III grinding stage target surface quality grade and then carry out subsequent processing.Compared with prior art, the aspheric optical element processing method of the application can improve overall processing efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aspheric optical element processing, and particularly to an aspheric optical element processing method. BACKGROUND

[0002] Aspheric optical elements have the advantages of small aberration, clear imaging, etc., and can achieve the effect of replacing a group of spherical optical elements with one or two aspheric optical elements. Therefore, small-caliber aspheric optical elements are being increasingly widely used in high-end instruments and equipment. However, compared with traditional spherical optical elements, aspheric optical elements are difficult to process, have poor precision, and are low in efficiency, and the high cost limits their further popularization and application.

[0003] The final processing surface precision of aspheric optical elements often reaches the micron or even sub-micron level, and the surface roughness reaches the nanometer level. The processing process involves grinding, polishing, and detection. The specific processing process is as follows: first, grinding is needed to quickly remove a large amount of material to achieve a surface precision of several microns to tens of microns; on this basis, polishing is performed to reduce the surface roughness and improve the surface precision; due to the uncertainty of processing, detection is needed after polishing to confirm whether the indicators are met, otherwise compensation polishing needs to be performed according to the detection results, and the polishing-detection process needs to be repeated until the indicators are met.

[0004] In order to improve the automation and intelligentization, the Chinese patent with the patent application number CN202310117169.4, “Grinding and Polishing and Detection Integrated Processing Equipment for Small-Caliber Aspheric Optical Elements”, integrates the grinding mechanism, the rough polishing mechanism, the fine polishing mechanism, the detection mechanism, and the workpiece clamping and conveying mechanism, so that the overall size is small and the installation space requirement is low. At the same time, the automatic conveying of the workpiece improves the automation and intelligentization, and the process conversion, processing, detection, etc. are automatically completed by the equipment, the manual operation is less, the operation personnel requirement is low, and the processing precision is not dependent on the experience of the operator.

[0005] However, in the grinding and polishing processes, the grinding process adopts fixed process parameters and fixed process indicators, has a large removal amount, high efficiency, short time, but poor surface quality, while the polishing process has low removal rate, low efficiency, long time, and good surface quality. Therefore, the polishing time is much longer than the grinding time in the overall processing flow. Moreover, due to the high surface precision after polishing, the possibility of compensation polishing caused by the uncertainty of processing is large, and the optical element after grinding often needs to wait for the polishing machine to complete the processing of the previous workpiece in production. This leads to low overall processing efficiency.

[0006] If the surface shape precision after grinding is improved, the removal amount of polishing can be reduced, thereby reducing the time required for polishing. However, the processing time and the probability of compensation grinding increase exponentially with the improvement of the surface shape precision, and do not change after reaching the limit of the equipment. The time required for polishing decreases with the improvement of the surface shape precision, but due to the diminishing marginal effect, the reduction speed of the time decreases with the improvement of the surface shape precision, and is almost unchanged. Therefore, too high or too low surface shape precision requirement will reduce the overall processing efficiency, and the uncertainty of compensation after processing will also cause poor connection between processes. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a non-spherical optical element processing method capable of improving the overall processing efficiency in view of the current situation of the prior art.

[0008] The technical solution adopted by the present application to solve the above technical problem is: a non-spherical optical element processing method, which adopts a grinding machine tool, a polishing machine tool and a surface shape detector to grind, polish and detect the optical element respectively, and is characterized by comprising the following steps:

[0009] Step one, establish a processing surface quality and processing time database;

[0010] Step two, start optical element processing, when the workpiece I completes grinding and detection, wait for polishing or complete a round of polishing and detection, then wait for compensation polishing, judge the polishing machine tool processing state:

[0011] For a single polishing machine tool manufacturing unit, judge whether it is processing, if yes, enter step three (a), if no, enter step three (b);

[0012] For a single polishing machine tool manufacturing unit, judge whether it is processing, if yes, enter step three (a), if no, enter step three (b);

[0013] Step three (a), optimal time matching of each station:

[0014] Record the current polishing machine tool as workpiece II, and the current grinding machine tool as workpiece III, calculate the remaining processing time required for the workpiece II in the polishing stage and the processing time required for the workpiece I in the next polishing stage;

[0015] In the database, the target surface quality grade of the grinding stage of the workpiece III is matched, so that the remaining processing and detection time required for the workpiece III to reach the target surface quality grade at the exit of the grinding stage is as close as possible to the sum of the remaining processing time required for the workpiece II in the polishing stage and the processing time required for the workpiece I in the next polishing stage.

[0016] Step three (b), matching of the shortest time of each station:

[0017] The current workpiece being processed by the grinding machine is denoted as workpiece III.

[0018] In the database, the target surface quality grade of the grinding stage of the workpiece III is matched, so that the sum of the remaining processing and detection time required for the workpiece III to reach the target surface quality grade at the exit of the grinding stage and the processing time required for the workpiece III in the next polishing stage is as small as possible.

[0019] Step four, adjusting the target surface quality grade of the grinding stage of the workpiece III and then performing subsequent processing.

[0020] Preferably, the process software is connected to the control systems of the grinding machine, the polishing machine and the surface profile detector, so that the process software controls the processing of the grinding machine and the polishing machine through communication and obtains the surface profile data measured by the surface profile detector.

[0021] During the processing of the optical element, the process software calculates the polishing trajectory and the dwell function of the optical element according to the surface profile of the optical element detected by the surface profile detector, and calculates the processing time required for one round of polishing.

[0022] Further, the step one is specifically implemented by the following method:

[0023] During the process of processing the mirror blank in the grinding stage to the highest surface quality that can be achieved, different surface qualities reached are divided into n+1 levels, each level is denoted as S0, S1, S2, …, Sn. n S0 is the state of the blank, S1 is the lowest surface quality grade that meets the entrance requirement of the polishing processing, and the relationship between the processing and detection time t i (i=0, 1, 2, …, n-1) required for processing from the S j (j=i+1, i+2, …, n) level to the S gij and the processing time t l (l=1, 2, …, n-1) required for the first round of polishing of the optical element with the entrance surface quality grade of S pl and S l is stored in the process software.

[0024] Furthermore, in step 3(a), the remaining processing time required for the current polishing stage of workpiece II and the processing time required for the next polishing stage of workpiece I are calculated using the following method:

[0025] If the polishing stage of workpiece II is the first round of polishing, the processing time required for the polishing stage of workpiece II is retrieved from the database, and then the remaining processing time t is calculated based on the used time. ps ;

[0026] If the workpiece II is polished in this round for compensation polishing, the processing time required for the workpiece II in this round of polishing is calculated based on the surface shape obtained in the previous round of detection, and then the remaining processing time t is calculated based on the used time. ps ;

[0027] If the next round of polishing for workpiece I is the first round of polishing, the processing time t required for the next round of polishing for workpiece I is retrieved from the database. pf ;

[0028] If the last round of polishing of workpiece I is compensation polishing, the processing time t required for the last round of polishing of workpiece I is calculated based on the surface shape obtained in this round of detection. pf .

[0029] Furthermore, in step 3 (a), the target surface quality level of the workpiece III grinding stage is matched in the database using the following method:

[0030] First, retrieve the original target surface quality level S of workpiece III in this round of grinding from the database. i and processing and testing time t 0i , and calculate the remaining processing and inspection time t based on the time used gs ;

[0031] Then search the database for the target surface quality grade S of the grinding workpiece j To meet:

[0032] T=min|(t gij +t gs )-(t pf +t ps )|;

[0033] Among them, t gij The surface quality level of the grinding stage is from S i to S j The processing and testing time required.

[0034] Furthermore, in step 3(b), the target surface quality level of the workpiece III grinding stage is matched in the database using the following method:

[0035] First, the original target surface quality grade S of the workpiece III in the current grinding stage is retrieved from the database i And the processing and detection time t 0i And the required remaining processing and detection time t gs is calculated according to the used time

[0036] Then search the grinding target surface quality grade S of the workpiece in the database j To meet:

[0037] T = min | (t gij +t gs )+t pj |

[0038] Where t gij is the processing and detection time required for the surface quality grade from S i to S j , t pj is the processing time required for the workpiece III to reach the surface quality grade S j after the first round of polishing.

[0039] Further, in step one, the grinding processing parameters of the surface quality grade from S i to S j are stored in the database.

[0040] Further, the fourth step is achieved by the following method:

[0041] First, adjust the target surface quality of the workpiece III to S j ;

[0042] Then the workpiece III completes the processing to the surface quality grade S i ;

[0043] Finally, the grinding processing parameters of the surface quality grade from S i to S j are retrieved from the database, and subsequent processing is continued.

[0044] Compared with the prior art, the advantages of the present application are: according to the actual processing condition, the exit surface quality of the grinding process is changed autonomously, the processing time of the grinding machine and the polishing machine is matched, the effective working time of the grinding machine is improved, part of the polishing stage workload is shared, and the problems of beat mismatch, long idle time of the grinding machine and low processing efficiency caused by the uncertainty of the polishing stage are avoided. The problems of long waiting time for polishing machine processing after grinding of optical elements, and the like are avoided, and the overall processing efficiency is improved. DETAILED DESCRIPTION

[0045] The application will be described in further detail below in connection with the embodiments.

[0046] In this embodiment, the grinding machine, the polishing machine and the surface profiler are used to grind, polish and detect the optical element respectively, and the process software is connected to the control systems of the grinding machine, the polishing machine and the surface profiler, so that the process software controls the machining process of the grinding machine and the polishing machine through communication and obtains the surface data measured by the surface profiler; during the machining process of the optical element, the process software calculates the polishing trajectory and the dwell function of the optical element according to the surface data measured by the surface profiler, and calculates the machining time required for one round of polishing.

[0047] The aspherical optical element machining method of this embodiment comprises the following steps:

[0048] Step one, establish the machining surface quality and machining time database:

[0049] The different surface qualities reached during the process of machining the mirror blank to the highest surface quality in the grinding stage are divided into n+1 levels, each level is respectively defined as S0, S1, S2, …, Sn, and the surface quality of the mirror blank is S0. n S0 is the state of the blank, S1 is the lowest surface quality level meeting the entrance requirement of polishing machining, and the machining and detection time t i (i=0, 1, 2, …, n-1) required for machining from the S j (i=0, 1, 2, …, n-1) level to the S gij (j=i+1, i+2, …, n) level is established, and the machining time t l (l=1, 2, …, n-1) required for the first round of polishing of the optical element with the entrance surface quality level of S pl and the S l is established, and stored in the process software; at the same time, the grinding machining process parameters of the surface quality level from S i to S j are stored in the database.

[0050] The corresponding relationship table of the starting surface quality level and the final surface quality level machining time is shown in Table 1 below:

[0051] Table 1

[0052]

[0053] Note: In the above table, the surface quality levels S0, S1, S2, …, Sn are used for the grinding stage; among the time required for machining from the starting surface quality level to the final surface quality level, the grinding stage time t n contains the machining and detection time, and the polishing stage time t gij . pjOnly processing time is included, without detection time.

[0054] The step of establishing database is only needed once for the same optical element, and is not repeated in the subsequent implementation of the method.

[0055] Step two, when the workpiece I is finished grinding and detection, and is waiting for polishing or is finished one round of polishing and detection and is waiting for compensation polishing, the polishing machine tool processing state is judged:

[0056] For a single polishing machine tool manufacturing unit, it is judged whether it is processing, if yes, step three (a) is entered, if no, step three (b) is entered;

[0057] For a multi-polishing machine tool manufacturing unit, it is judged whether all polishing machine tools are in processing state, if yes, the polishing machine tool with the shortest remaining processing time is selected for polishing of the workpiece I and step three (a) is entered, if no, one of the polishing machine tools not in processing state is selected for polishing of the workpiece I and step three (b) is entered.

[0058] Step three (a), optimal time matching of each station:

[0059] (1) the polishing machine tool current processing workpiece is recorded as workpiece II, the grinding machine tool current processing workpiece is recorded as workpiece III, the remaining processing time required by the workpiece II in the current polishing stage and the processing time required by the workpiece I in the next polishing stage are calculated:

[0060] If the workpiece II in the current polishing stage is the first polishing, the processing time required by the workpiece II in the current polishing stage is first retrieved from the database, and then the remaining processing time t ps required is calculated according to the time already used;

[0061] If the workpiece II in the current polishing stage is compensation polishing, the processing time required by the workpiece II in the current polishing stage is first calculated according to the surface shape obtained by the previous detection, and then the remaining processing time t ps required is calculated according to the time already used;

[0062] If the workpiece I in the next polishing stage is the first polishing, the processing time t pf required by the workpiece I in the next polishing stage is first retrieved from the database;

[0063] If the workpiece I in the next polishing stage is compensation polishing, the processing time t pf required by the workpiece I in the next polishing stage is first calculated according to the surface shape obtained by the current detection;

[0064] (2) Match the target surface quality level of workpiece III in the grinding stage in the database so that the remaining processing and inspection time required for the outlet surface quality level of workpiece III in this round of grinding stage to reach the target surface quality level is as close as possible to the sum of the remaining processing time required for workpiece II in this round of polishing stage and the processing time required for the next round of polishing stage of workpiece I:

[0065] ① First retrieve the target surface quality level S of workpiece III in this round of grinding from the database i and processing and testing time t 0i , and calculate the remaining processing and inspection time t based on the time used gs ;

[0066] ② Then search the database for the target surface quality grade S of the grinding workpiece j To meet:

[0067] T=min|(t gij +t gs )-(t pf +t ps )|;

[0068] Among them, t gij The surface quality level of the grinding stage is from S i to S j The processing and testing time required.

[0069] In this way, after the polishing machine performs a round of polishing on workpiece II and workpiece I in sequence, it can start polishing workpiece III as soon as possible.

[0070] Step 3 (b), shortest time matching for each workstation:

[0071] (1) The workpiece currently being processed by the grinding machine is recorded as workpiece III;

[0072] (2) Match the target surface quality level of workpiece III in the grinding stage in the database so that the remaining processing and inspection time required to achieve the target surface quality level at the outlet of workpiece III in this round of grinding and the processing time required for the next round of polishing of workpiece III are as small as possible:

[0073] ① First retrieve the target surface quality level S of workpiece III in this round of grinding from the database i and processing and testing time t 0i , and calculate the remaining processing and inspection time t based on the time used gs ;

[0074] ② Then search the database for the target surface quality grade S of the grinding workpiece j To meet:

[0075] T=min|(tgij +t gs )+t pj |;

[0076] wherein, t gij is the processing and detection time required for the surface quality grade of the grinding stage to change from S i to S j , t pj is the processing time required for the first polishing after the surface quality grade of the workpiece III at the exit of the grinding stage reaches S j .

[0077] In this way, the total processing time of the grinding and the first polishing of the workpiece III can be ensured to be the shortest.

[0078] Step four, adjusting the target surface quality grade of the workpiece III at the grinding stage and then carrying out subsequent processing:

[0079] ①First, adjust the target surface quality of the workpiece III to S j .

[0080] ②Then, complete the processing of the workpiece III to the surface quality grade S i .

[0081] ③Finally, retrieve the grinding processing parameters of the grinding stage from the database, wherein the surface quality grade changes from S i to S j , and then continue to carry out subsequent processing.

[0082] The above scheme has the following advantages:

[0083] (1) Through the prediction of the processing situation of the existing workpiece, only part of the process parameters need to be changed to quickly adjust the processing technology scheme, and the process is simple, without the need for complex hardware cooperation;

[0084] (2) Through the adjustment of the exit index of the grinding stage, independent decision-making can be realized, which can reduce the idle time of the equipment, reasonably allocate the removal amount of the grinding and polishing processes in the processing process, and effectively improve the overall processing efficiency of the grinding and polishing;

[0085] (3) No requirement for the number of grinding machines and polishing machines, and at least one grinding machine and one polishing device can be used, and when the number of devices is large, the processing efficiency can be improved better by using the method;

[0086] (4) For grinding and polishing processing equipment using traditional processing methods, the equipment does not need to be greatly adjusted, and only by adding a host computer of the total control, configuring process software, and connecting a data interface, the method can be applied;

[0087] (5) The method is simple to use, with high automation, and no professional training is required.

Claims

1. A method for processing an aspherical optical element, which uses a grinding machine, a polishing machine and a surface profile tester to grind, polish and test the optical element, respectively, characterized in that It comprises the following steps: Step one, establishing the database of the surface quality and processing time; Step two, starting the processing of the optical element, when the workpiece I is finished grinding and detecting, waiting for polishing or after finishing a round of polishing and detecting, waiting for compensating polishing, judging the processing state of the polishing machine tool: For the manufacturing unit of single polishing machine tool, judging whether it is processing, if yes, entering step three (a), if no, entering step three (b); For the manufacturing unit of multiple polishing machine tools, judging whether all polishing machine tools are in the processing state, if yes, selecting the polishing machine tool with the shortest remaining processing time for the polishing of the workpiece I and entering step three (a), if no, selecting one of the polishing machine tools not in the processing state for the polishing of the workpiece I and entering step three (b); Step three (a), optimal time matching of each work station: Recording the current processing workpiece of the polishing machine tool as workpiece II, recording the current processing workpiece of the grinding machine tool as workpiece III, calculating the remaining processing time required by the workpiece II in the polishing stage and the processing time required by the workpiece I in the next polishing stage; In the database, matching the target surface quality level of the workpiece III in the grinding stage, so that the remaining processing and detecting time required by the workpiece III in the grinding stage to reach the target surface quality level is as close as possible to the sum of the remaining processing time required by the workpiece II in the polishing stage and the processing time required by the workpiece I in the next polishing stage; Step three (b), shortest time matching of each work station: Recording the current processing workpiece of the grinding machine tool as workpiece III; In the database, matching the target surface quality level of the workpiece III in the grinding stage, so that the sum of the remaining processing and detecting time required by the workpiece III in the grinding stage to reach the target surface quality level and the processing time required by the workpiece III in the next polishing stage is as small as possible; Step four, adjusting the target surface quality level of the workpiece III in the grinding stage and then processing.

2. The aspherical optical element processing method according to claim 1, wherein: The process software is connected with the control systems of the grinding machine tool, the polishing machine tool and the surface shape detector, so that the process software controls the processing process of the grinding machine tool and the polishing machine tool through communication and obtains the surface shape data measured by the surface shape detector; In the processing of the optical element, the process software calculates the polishing track and the dwell function of the optical element according to the surface shape of the optical element detected by the surface shape detector, and calculates the processing time required by one round of polishing.

3. The aspherical optical element processing method according to claim 2, wherein: The step one is realized by the following method: The different surface qualities reached in the process of machining the mirror blank in the grinding stage to the highest surface quality that can be achieved are divided into n+1 levels, each level being designated S0, S1, S2, …, S n where S0 is the state of the blank piece, S1 is the lowest surface quality level that meets the entrance requirements for polishing machining, and the machining and detection times t i (i = 0, 1, 2, …, n-1) required to machine from the S j (i = 0, 1, 2, …, n-1) level to the S gij (j = i+1, i+2, … n) level are established, as well as the relationship between the polishing machining times t l (l = 1, 2, …, n-1) required for the first round of polishing of the optical element with an entrance surface quality level of S pl and S l , and are stored in the process software.

4. The aspherical optical element processing method according to claim 3, wherein: In the step three (a), the remaining processing time required by the workpiece II in the polishing stage and the processing time required by the workpiece I in the next polishing stage are calculated by the following method: If the current polishing stage of the workpiece II is the first polishing stage, the processing time required by the current polishing stage of the workpiece II is first called from the database, and then the remaining processing time t required by the current polishing stage is calculated according to the used time ps ; If the current polishing stage of the workpiece II is a compensation polishing, the machining time required by the current polishing stage of the workpiece II is calculated according to the surface shape obtained in the previous detection, and then the remaining machining time t required is calculated according to the time used ps ; If the next polishing stage of the workpiece I is the first polishing, the processing time t required by the next polishing stage of the workpiece I is first called from the database pf ; If the next polishing stage of the workpiece I is a compensation polishing, the processing time t required for the next polishing stage of the workpiece I is calculated according to the surface shape obtained in the present detection pf .

5. The aspherical optical element processing method according to claim 4, wherein: In the step three (a), the target surface quality level of the workpiece III in the grinding stage is matched in the database by the following method: The original target surface quality grade S of the workpiece III in the present grinding stage is first called from the database i and the machining and testing time t 0i and the required remaining machining and testing time t gs is calculated according to the used time Then the grinding workpiece target surface quality grade S is searched in the database j to satisfy: T = min |(t gij + t gs - t pf + t ps )|; where t gij is the surface quality grade from S i to S j required processing and detection time.

6. The aspherical optical element processing method according to claim 3, wherein: In the step three (b), the target surface quality level of the workpiece III in the grinding stage is matched in the database by the following method: The original target surface quality grade S of the workpiece III in the present grinding stage is first called from the database i and the machining and testing time t 0i and the required remaining machining and testing time t gs is calculated according to the used time Then the grinding workpiece target surface quality grade S is searched in the database j to satisfy: T = min |(t gij + t gs + t pj |; Among them, t gij The surface quality level of the grinding stage is from S i to S j Required processing and testing time, t pj The surface quality level of the workpiece at the exit of the grinding stage III reaches S j The processing time required for the first round of polishing.

7. The aspherical optical element processing method according to any one of claims 3 to 6, wherein: The grinding stage surface quality grade from S i to S j is stored in the database in step one.

8. The aspherical optical element processing method according to claim 7, wherein: The step four is realized by the following method: Adjusting the target surface quality of the workpiece III to S j ; The workpiece III is then finished to a surface quality grade S i of machining; Finally the surface quality grade of the grinding stage is called from the database from S i to S j the grinding process parameters and the subsequent machining is continued.

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