Method for processing aspheric optical element

Abstract

The invention discloses an aspheric optical element machining method. The aspheric optical element machining method is characterized by comprising the following steps that firstly, a machined surface quality and machining time database is established; 2, optical element machining is started, and when a workpiece I waits for polishing after being ground and detected or waits for compensation polishing after being subjected to one-round polishing and detection, the machining state of a polishing machine tool is judged; 3, the optimal time of all the stations is matched; 3, the shortest time of all the stations is matched; and 4, the target surface quality grade of the workpiece III in the grinding stage is adjusted, and then follow-up machining is conducted. Compared with the prior art, the machining method of the aspheric optical element can improve the overall machining efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of aspheric optical element processing, and in particular to a method for processing an aspheric optical element. Background Art

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

[0003] The final processing surface accuracy requirements of aspheric optical components often reach the micron or even sub-micron level, and the surface roughness reaches the nanometer level. The processing process involves grinding, polishing and testing. The specific processing process is as follows: First, grinding is required to quickly remove a large amount of material to achieve a surface accuracy of several microns to tens of microns; on this basis, polishing is performed to reduce the surface roughness and improve the surface accuracy; due to the uncertainty of processing, after the polishing is completed, it is necessary to test to confirm that the indicators are met, otherwise it is necessary to perform compensatory polishing according to the test results, and repeat the polishing-testing process until the indicators are met.

[0004] In order to improve the degree of automation and intelligence, the Chinese patent application number CN202310117169.4 "An integrated processing equipment for grinding, polishing and inspection of small-aperture aspheric optical elements" integrates the grinding mechanism, rough polishing mechanism, fine polishing mechanism, detection mechanism and workpiece clamping and transmission mechanism into one, with a small overall size and low requirements for installation space; at the same time, the automatic transmission of workpieces improves the degree of automation and intelligence, and the process conversion, processing, inspection and other links are all automatically completed by the equipment, with fewer manual operation links, low requirements for operators, and the processing accuracy does not depend on the operator's experience.

[0005] However, in the two processes of grinding and polishing, the grinding process uses fixed process parameters and fixed process indicators, with large removal volume, 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 in the overall processing flow is much longer than the grinding time. Moreover, due to the high shape accuracy after polishing, the possibility of compensatory polishing caused by the uncertainty of processing is relatively large. In production, it is often the case that the optical components after grinding are waiting for the polishing machine to complete the processing of the previous workpiece. This leads to low overall processing efficiency.

[0006] If the surface accuracy after grinding is improved, the amount of polishing removal can be reduced, thereby reducing the time required for polishing. However, as the grinding surface accuracy is improved, the processing time and the probability of compensation grinding will increase exponentially with the increase in surface accuracy requirements, and will no longer change after reaching the equipment limit. The time required for polishing will decrease with the improvement of grinding surface accuracy, but due to the diminishing marginal benefits effect, the rate of time reduction decreases with the improvement of grinding surface accuracy until it remains almost unchanged. Therefore, too high or too low grinding surface accuracy requirements will result in a decrease in overall processing efficiency, and the uncertainty of post-processing compensation will also result in poor connection between processes. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for processing aspheric optical elements that can improve the overall processing efficiency in view of the current status of the prior art.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: a method for processing aspheric optical elements, using a grinding machine, a polishing machine and a surface detector to grind, polish and detect the optical elements respectively, characterized in that it includes the following steps:

[0009] Step 1: Establish a database of machining surface quality and machining time;

[0010] Step 2: Start optical component processing. When workpiece I is waiting for polishing after grinding and testing, or waiting for compensation polishing after completing one round of polishing and testing, determine the processing status of the polishing machine:

[0011] For a manufacturing unit of a single polishing machine tool, determine whether it is being processed, if so, proceed to step 3(a), if not, proceed to step 3(b);

[0012] For a manufacturing unit with multiple polishing machines, determine whether all the polishing machines are in a processing state. If so, select a polishing machine with the shortest remaining processing time for polishing workpiece I and proceed to step 3(a). If not, select one of the polishing machines that is not in a processing state for polishing workpiece I and proceed to step 3(b).

[0013] Step 3 (a), optimal time matching for each workstation:

[0014] The workpiece currently processed by the polishing machine is recorded as workpiece II, and the workpiece currently processed by the grinding machine is recorded as workpiece III. 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;

[0015] 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;

[0016] Step 3 (b), shortest time matching for each workstation:

[0017] The workpiece currently being processed by the grinding machine is recorded as workpiece III;

[0018] 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 and the sum of the processing time required for the next round of polishing stage of workpiece III are as small as possible;

[0019] Step 4: Adjust the target surface quality level of the workpiece in the grinding stage III before proceeding with subsequent processing.

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

[0021] During the processing of optical components, the process software will calculate the polishing trajectory and residence function based on the surface shape of the optical component detected by the surface detector, and calculate the processing time required for a round of polishing.

[0022] Furthermore, the step 1 is specifically implemented by the following method:

[0023] The different surface qualities achieved during the grinding process of the mirror blank to the highest achievable surface quality are divided into n+1 levels, and each level is defined as S0, S1, S2, ..., S n , where S0 is the blank state, S1 is the minimum surface quality level that meets the polishing process entry requirements, and establishes the i (i=0,1,2,…,n-1) level processing to S j The processing and inspection time t required for level (j=i+1,i+2,…n) gij And the polishing stage has S l The processing time t required for the first round of polishing of optical components with the entrance surface quality level (l=1,2,…,n-1) pl With S l The relationship between them is calculated and 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 by the following method:

[0025] If the current polishing stage of workpiece II is the first round of polishing, the processing time required for the current 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 current polishing stage of workpiece II is compensatory polishing, the processing time required for the current polishing stage of workpiece II 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 of workpiece I is the first round of polishing, the processing time t required for the next round of polishing of workpiece I is retrieved from the database first. pf ;

[0028] If the next round of polishing of workpiece I is compensatory polishing, the processing time t required for the next 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, 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 ;

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

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

[0038] 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.

[0039] Furthermore, in the step 1, the surface quality level of the grinding stage is stored in the database from S i To S j Grinding process parameters.

[0040] Furthermore, the step 4 is specifically implemented by the following method:

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

[0042] Then workpiece III is completed to surface quality grade S i processing;

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

[0044] Compared with the prior art, the advantages of the present invention are: autonomous decision-making to change the outlet surface quality of the grinding process according to actual processing conditions, matching the processing time on the grinding machine and the polishing machine, increasing the effective working time of the grinding machine, sharing part of the workload of the polishing stage, and avoiding the situation in which, under the traditional fixed grinding surface quality index, the optical element needs to wait for a long time for the polishing machine to complete the processing due to the uncertainty of the polishing stage, thus causing problems such as beat mismatch, long idle time of the grinding machine, low processing efficiency, etc., thereby improving the overall processing efficiency. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below with reference to the embodiments.

[0046] This embodiment uses a grinding machine, a polishing machine and a surface detector to grind, polish and detect optical elements respectively, and uses process software to connect with the control systems of the grinding machine, the polishing machine and the surface detector, so that the process software can control the processing of the grinding machine and the polishing machine through communication, and obtain the surface data measured by the surface detector; in the process of processing the optical element, the process software will calculate its polishing trajectory and residence function according to the surface shape of the optical element detected by the surface detector, and calculate the processing time required for one round of polishing.

[0047] The aspheric optical element processing method of this embodiment includes the following steps:

[0048] Step 1: Establish a database of machining surface quality and machining time:

[0049] The different surface qualities achieved during the grinding process of the mirror blank to the highest achievable surface quality are divided into n+1 levels, and each level is defined as S0, S1, S2, ..., S n , where S0 is the blank state, S1 is the minimum surface quality level that meets the polishing process entry requirements, and establishes the i (i=0,1,2,…,n-1) level processing to S j The processing and inspection time t required for level (j=i+1,i+2,…n) gij And the polishing stage has S l The processing time t required for the first round of polishing of optical components with the entrance surface quality level (l=1,2,…,n-1) pl With S l The relationship between S and G is stored in the process software; at the same time, the surface quality level of the grinding stage is stored in the database from S i To S j Grinding process parameters.

[0050] The corresponding relationship between the initial surface quality grade and the final surface quality grade processing time is shown in Table 1 below:

[0051] Table 1

[0052]

[0053] Note: Surface quality grades in the above table are S0, S1, S2, ..., S n For the grinding stage; the time required to process from the initial surface quality level to the final surface quality level, the grinding stage time t gij Including processing and testing time, polishing stage time t pjOnly processing time is included, not inspection time.

[0054] The step of establishing a database only needs to be established once for the same optical element, and does not need to be repeated in subsequent implementations of the method.

[0055] Step 2: Start optical component processing. When workpiece I is waiting for polishing after grinding and testing, or waiting for compensation polishing after completing one round of polishing and testing, determine the processing status of the polishing machine:

[0056] For a manufacturing unit of a single polishing machine tool, determine whether it is being processed, if so, proceed to step 3(a), if not, proceed to step 3(b);

[0057] For a manufacturing unit with multiple polishing machines, determine whether all the polishing machines are in a processing state. If so, select a polishing machine with the shortest remaining processing time for polishing workpiece I and proceed to step three (a). If not, select one of the polishing machines that is not in a processing state for polishing workpiece I and proceed to step three (b).

[0058] Step 3 (a), optimal time matching for each workstation:

[0059] (1) The workpiece currently being processed by the polishing machine is recorded as workpiece II, and the workpiece currently being processed by the grinding machine is recorded as workpiece III. 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:

[0060] If the current polishing stage of workpiece II is the first round of polishing, the processing time required for the current 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 ;

[0061] If the current polishing stage of workpiece II is compensatory polishing, the processing time required for the current polishing stage of workpiece II 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 ;

[0062] If the next round of polishing of workpiece I is the first round of polishing, the processing time t required for the next round of polishing of workpiece I is retrieved from the database first. pf ;

[0063] If the next round of polishing of workpiece I is compensatory polishing, the processing time t required for the next round of polishing of workpiece I is calculated based on the surface shape obtained in this round of detection. pf ;

[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 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 ;

[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 has completed 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 for the outlet surface quality level of workpiece III in this round of grinding stage to reach the target surface quality level and the sum of the processing time required for the next round of polishing stage of workpiece III are as small as possible:

[0073] ① 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 ;

[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] 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.

[0077] In this way, the total processing time of workpiece III grinding and the first round of polishing can be kept to a minimum.

[0078] Step 4: Adjust the target surface quality level of the workpiece in the grinding stage III before subsequent processing:

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

[0080] ②Then workpiece III is completed to surface quality grade S i processing;

[0081] ③Finally, the surface quality grade of the grinding stage is retrieved from the database from S i To S j The grinding process parameters are determined and subsequent processing is continued.

[0082] The advantages of the above scheme are:

[0083] (1) By predicting the processing conditions of existing workpieces, the processing plan can be quickly adjusted by changing only some process parameters. The process is simple and does not require complex hardware coordination;

[0084] (2) By adjusting the export indicators of the grinding stage to achieve independent decision-making, the idle time of equipment can be reduced, the removal volume of the two processes of grinding and polishing can be reasonably allocated during the processing, and the overall processing efficiency of grinding and polishing can be effectively improved;

[0085] (3) There is no requirement for the number of grinding machines and polishing machines. At least one grinding machine and one polishing equipment are applicable. When the number of equipment is large, this method can achieve better processing efficiency improvement;

[0086] (4) For grinding and polishing equipment using traditional processing methods, there is no need to make major adjustments to the equipment. This method can be applied by simply adding a master control computer, configuring process software, and connecting a data interface;

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

Claims

1. A method for processing an aspherical optical element, wherein a grinding machine, a polishing machine and a surface shape detector are used to grind, polish and detect the optical element respectively, characterized in that The following steps are included: Step 1: Establish a database of machining surface quality and machining time; Step 2: Start optical component processing. When workpiece I is waiting for polishing after grinding and testing, or waiting for compensation polishing after completing a round of polishing and testing, determine the processing status of the polishing machine: For a manufacturing unit of a single polishing machine tool, determine whether it is being processed, if so, proceed to step 3(a), if not, proceed to step 3(b); For a manufacturing unit with multiple polishing machines, determine whether all the polishing machines are in a processing state. If so, select a polishing machine with the shortest remaining processing time for polishing workpiece I and proceed to step 3(a). If not, select one of the polishing machines that is not in a processing state for polishing workpiece I and proceed to step 3(b). Step 3 (a), optimal time matching for each workstation: The workpiece currently processed by the polishing machine is recorded as workpiece II, and the workpiece currently processed by the grinding machine is recorded as workpiece III. 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; 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; Step 3 (b), shortest time matching for each workstation: The workpiece currently being processed by the grinding machine is recorded as workpiece III; 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 and the sum of the processing time required for the next round of polishing stage of workpiece III are as small as possible; Step 4: Adjust the target surface quality level of the workpiece in the grinding stage III before proceeding with subsequent processing.

2. The method for processing an aspherical optical element according to claim 1, characterized in that: The process software is connected to the control systems of the grinding machine, the polishing machine and the surface detector, so that the process software controls the processing of the grinding machine and the polishing machine through communication and obtains the surface data measured by the surface detector; During the processing of optical components, the process software will calculate the polishing trajectory and residence function based on the surface shape of the optical component detected by the surface detector, and calculate the processing time required for a round of polishing.

3. The method for processing an aspherical optical element according to claim 2, wherein: The step 1 is specifically implemented by the following method: The different surface qualities achieved during the grinding process of the mirror blank to the highest achievable surface quality are divided into n+1 levels, and each level is defined as S0, S1, S2, ..., S n , where S0 is the blank state, S1 is the minimum surface quality level that meets the polishing process entry requirements, and establishes the i (i=0,1,2,…,n-1) level processing to S j The processing and inspection time t required for level (j=i+1,i+2,…n) gij And the polishing stage has S l The processing time t required for the first round of polishing of optical components with the entrance surface quality level (l=1,2,…,n-1) pl With S l The relationship between them is calculated and stored in the process software.

4. The method for processing an aspherical optical element according to claim 3, characterized in that: 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 by the following method: If the current polishing stage of workpiece II is the first round of polishing, the processing time required for the current 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 ; If the current polishing stage of workpiece II is compensatory polishing, the processing time required for the current polishing stage of workpiece II 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 ; If the next round of polishing of workpiece I is the first round of polishing, the processing time t required for the next round of polishing of workpiece I is retrieved from the database first. pf ; If the next round of polishing of workpiece I is compensatory polishing, the processing time t required for the next round of polishing of workpiece I is calculated based on the surface shape obtained in this round of detection. pf .

5. The method for processing an aspherical optical element according to claim 4, characterized in that: In step 3 (a), the target surface quality level of the workpiece III grinding stage is matched in the database using the following method: 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 ; Then search the database for the target surface quality grade S of the grinding workpiece j To meet: T=min|(t gij +t gs )-(t pf +t ps )|; 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.

6. The method for processing an aspherical optical element according to claim 3, characterized in that: In step 3 (b), the target surface quality level of the workpiece III grinding stage is matched in the database using the following method: 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 ; Then search the database for the target surface quality grade S of the grinding workpiece j To meet: 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 method for processing an aspherical optical element according to any one of claims 3 to 6, characterized in that: In the step 1, the surface quality level of the grinding stage is stored in the database from S i To S j Grinding process parameters.

8. The method for processing an aspherical optical element according to claim 7, characterized in that: The step 4 is specifically implemented by the following method: First adjust the target surface quality of workpiece III to S j ; Then workpiece III is completed to surface quality grade S i processing; Finally, the surface quality grade of the grinding stage is retrieved from the database from S i To S j The grinding process parameters are determined and subsequent processing is continued.

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