An on-board optical machine product screw anti-loosening process parameter optimization method and device

Abstract

This invention relates to a method and apparatus for optimizing the process parameters of screw anti-loosening in airborne optical engine products. The optimization apparatus mainly consists of an optical reference, a platform, an autocollimating optical instrument, and a loading instrument. The screws of the airborne optical engine products to be selected include optical lenses and screws. The optical lenses can be lenses, mirrors, or prisms. The optimization method includes determining the influencing factors related to screw anti-loosening, collecting the position of the optical reference, collecting the position of each group of optical lenses, applying an environmental load, collecting the position of the optical reference and each group of optical lenses after unloading, calculating the optical lens offset, and optimizing the process parameters. This invention measures the positional change of the optical lenses before and after the load to reflect the loosening of the screw, achieving high detection accuracy; it optimizes the screw tightening process parameters by directly measuring the offset of the fixed optical lenses, meaning the process parameters directly reflect the offset of the optical lenses.

Description

Technical Field

[0001] This invention belongs to the field of airborne optical instrument assembly technology, specifically relating to a method and apparatus for optimizing anti-loosening process parameters of airborne optical and mechanical products. Background Technology

[0002] Airborne optical instruments typically experience a wide range of temperature loads and aircraft vibrations within a complete mission profile. To ensure that changes in the relative positions of the lenses in the instrument's optical system remain within optical tolerances, the anti-loosening process parameters for the optical lenses need to be optimized. A common method for optimizing anti-loosening process parameters is to place the parts to be anti-loosened under load and then check for loose screws, usually visually. Based on the inspection results, the selected process parameters are determined. According to engineering experience, a screw loosening of at least 3° can be identifiable by visual inspection. In airborne optical instruments, due to the high requirements for the relative positions of the lenses, the reliability and accuracy of the anti-loosening method are crucial. General methods have low detection accuracy; if no loosening is detected visually, the anti-loosening performance is insufficient for the requirements of airborne optical instruments. Therefore, a method and apparatus for optimizing the anti-loosening process parameters for screws in airborne optomechanical products are needed to meet the high-precision anti-loosening requirements of optical instruments. Summary of the Invention

[0003] To overcome the shortcomings of low detection accuracy in general methods for optimizing anti-loosening process parameters, this invention proposes a method and apparatus for optimizing anti-loosening process parameters of screws in airborne optomechanical products.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows:

[0005] A device for optimizing the anti-loosening process parameters of screws in airborne optical machinery products mainly consists of an optical reference, a platform, an autocollimating optical instrument, and a loading instrument.

[0006] The optical references are fixed on the platform, and 1 to 6 can be arranged side by side in parallel. The optical references and the autocollimating optical instrument are located at opposite ends of the platform. The autocollimating optical instrument reads the positions of the reflected images of the optical references and optical lenses through a display.

[0007] The candidate airborne optical instrument product screws include optical lenses and screws, which fix the optical lenses to the platform. The optical lenses are located between the optical reference and the autocollimating optical instrument. The optical lenses are components that reflect light and can be lenses, mirrors, or prisms.

[0008] The platform is equipped with an optical reference interface, a platform interface, and screw holes. The optical reference is a reflector, which is fixed to the platform via the optical reference interface. The screw holes are matched with screws for fixing the optical lens.

[0009] The flatness of the mirror is not less than 0.5λ@632.8nm, and the reflectivity is not less than 99%.

[0010] The loading instrument includes a vibration table and a temperature shock chamber. The vibration table is fixedly connected to the platform interface, and the platform is fixed to the vibration table through the platform interface. The temperature shock chamber is placed outside the platform, that is, the platform and the screws of the candidate optical engine product are placed inside the temperature shock chamber.

[0011] The temperature shock chamber has a temperature range of -60℃ to 90℃ and a temperature change rate of no more than 3℃ / min; the vibration table has a frequency range of 0 to 2000Hz and a load of no less than 50Kg.

[0012] In the preferred embodiment described above, the reflector is made of flat optical glass.

[0013] In the preferred device described above, the reflector is made of a prism.

[0014] In the preferred device described above, the reflector is a reflective film sintered on a metal substrate.

[0015] A method for optimizing screw anti-loosening process parameters in airborne optical machinery products includes the following steps:

[0016] Step 1: Identify the influencing factors related to screw loosening prevention.

[0017] Determine the process parameters related to screw loosening prevention, and group the process parameters according to the test method of orthogonal experiment.

[0018] Three factors affecting the anti-loosening performance of screws were selected: spring washer material, tightening torque, and thread engagement length. Different levels were set for each factor.

[0019] Adding spring washers or applying adhesive is one of the anti-loosening techniques.

[0020] The selected spring washer material, tightening torque, and thread engagement length are each numbered.

[0021] The influencing factors, spring washer material A, tightening torque B, and thread engagement length C, were combined at different levels according to the orthogonal test method. Each combination is a process parameter.

[0022] Step 2, acquire the position of the optical reference.

[0023] The optical reference and platform are stabilized.

[0024] The position of the optical reference is acquired using an autocollimating optical instrument and recorded as (x, y).

[0025] Step 3: Collect the position of each set of optical lenses.

[0026] Using the process parameters determined in step 1, screws and spring washers are used to install the optical lenses onto the screw holes. During installation, the lenses are fixed onto the test platform in order of distance from the autocollimating optical instrument, from farthest to near, and the positions of the optical lenses are recorded sequentially.

[0027] Each set of optical lenses corresponds to a set of process parameters.

[0028] Step 4, Apply environmental loads

[0029] After installation, the test platform is mounted on the vibration table, and vibration load is applied to the test platform according to the required vibration level and time.

[0030] The test platform was removed from the vibration platform and placed in a temperature shock chamber. Temperature cycling was performed within the temperature range of -55℃ to 70℃, with a temperature change rate of 3℃ / min, for a total of 8 cycles.

[0031] Step 5: Collect the optical reference and the position of each group of optical lenses after unloading.

[0032] Remove environmental loads.

[0033] The position of each optical lens is recorded sequentially using an autocollimating optical instrument.

[0034] Multiple optical lenses were removed sequentially from near to far from the autocollimating optical instrument. Before removal, the position of each optical lens was recorded sequentially using the autocollimating optical instrument. After all lenses were removed, the position of the optical reference was recorded.

[0035] Step 6, Calculate the offset

[0036] Based on the optical reference and the positional changes of each group of optical lenses before and after the application of environmental load, the data is processed according to the data processing method of orthogonal experiment to obtain the offset of each group of optical lenses relative to the optical reference.

[0037] Step 7, Selecting the optimal process parameters

[0038] Based on the offset corresponding to each set of process parameters, the set of process parameters with the smallest offset relative to the optical reference position can be selected, or multiple sets of process parameters that meet the product requirements can be selected.

[0039] This invention solves the problem of optimizing anti-loosening process parameters in airborne optical machinery products, and can measure minute variations caused by anti-loosening measures. It has the following advantages:

[0040] (1) High detection accuracy: This invention measures the positional change of the optical lens before and after the load to reflect the loosening of the screw. A general autocollimating optical instrument can achieve a detection accuracy of 0.1″, which is much higher than the 3° accuracy of visual inspection.

[0041] (2) The process parameters are highly transferable. This invention optimizes the screw fastening process parameters by directly measuring the offset of the fixed optical lens. That is, the process parameters directly reflect the offset of the optical lens. The process parameters obtained by the traditional optimization method cannot directly correspond to the offset of the optical lens.

[0042] (3) It is highly flexible and can adjust the evaluation criteria for tolerance in different optical systems and adjust the test platform according to the different process parameters being studied.

[0043] (4) High research efficiency: By increasing the number of optical lenses that are fastened, effective conclusions can be drawn from a single environmental test for a combination of various process parameters, which greatly saves time, economic and human resources costs. Attached Figure Description

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0045] Figure 1 This is a schematic diagram of the device structure of the present invention;

[0046] Figure 2 This is a schematic diagram of the platform structure.

[0047] In the diagram: 1. Optical reference; 2. Optical lens; 3. Platform; 4. Screw; 5. Autocollimating optical instrument; 31. Optical reference interface; 32. Platform interface; 33. Screw hole. Detailed Implementation

[0048] Example

[0049] A device for optimizing the anti-loosening process parameters of screws in airborne optical machinery products includes an optical reference 1, a platform 3, an autocollimating optical instrument 5, and a loading instrument, such as... Figure 1 As shown.

[0050] Optical reference 1 is fixed on platform 3. Optical reference 1 and autocollimating optical instrument 5 are located at opposite ends of platform 3. The optical reference 1 is fixedly connected to platform 3 by bonding or sintering.

[0051] Optical reference 1 is a reflector, which can be made of flat optical glass or a prism, or a reflective film sintered on a metal substrate. The flatness of the reflector is not less than 0.5λ@632.8nm, and the reflectivity is not less than 99%. N optical references 1 can be arranged side by side in parallel, where N = 1 to 6.

[0052] After the optical reference 1 is installed on the platform 3, it needs to undergo stress relief treatment such as vibration and high and low temperature to ensure that the relative positions of the two do not change during the test.

[0053] The collimating optical instrument platform 5 emits light, which shines on the reflector, causing some or all of the reflected light to be reflected onto the receiving screen of the collimating optical instrument platform 5.

[0054] The autocollimating optical instrument 5 includes a light source, a shaping optical path, a crosshair reticle, and a display module. The light emitted by the autocollimating optical instrument 5 shines on the reflector, causing the reflected light from the reflector to be reflected onto the display module of the autocollimating optical instrument 5.

[0055] The autocollimating optical instrument 5 reads the positions of the reflected images of the optical reference 1 and the optical lens 2 through the display.

[0056] Platform 3 is provided with an optical reference interface 31, a platform interface 32, and screw holes 33. Screw holes 33 are matched with screws 4 for fixing optical lenses 2. Optical reference 1 is fixed to platform 3 through optical reference interface 31.

[0057] The loading instruments include a vibration table and a temperature shock chamber. The vibration table is fixedly connected to the platform interface 32, and the platform 3 and the screws of the selected optical engine product are placed inside the temperature shock chamber.

[0058] Platform 3 is fixed to the vibration table via platform interface 32.

[0059] Temperature shock chamber, with a temperature change range of -60℃ to 90℃ and a temperature change rate of no more than 3℃ / min.

[0060] The vibration table has a frequency range of 0 to 2000 Hz and a load of not less than 50 kg.

[0061] The candidate airborne optical instrument product is optical lens 2, and the candidate airborne optical instrument product screw is screw 4. The screws for the candidate airborne optical instrument product include optical lens 2 and screw 4, with screw 4 fixing optical lens 2 onto platform 3. Optical lens 2 is placed on platform 3, located between optical reference 1 and autocollimating optical instrument 5. Optical lens 2 is a component that reflects light and can be a lens, mirror, or prism. When using screw 4 to fix optical lens 2, spring washers can also be added to enhance the anti-loosening effect. Optical lens 2 is located on the path of light emitted from autocollimating optical instrument 5 to optical reference 1. n candidate airborne optical instruments can be arranged, where n = 1 to 200.

[0062] Optical lens 2 is a plane mirror with a flatness of not less than 0.5λ@632.8nm and a reflectivity of not less than 99%.

[0063] The position of an optical lens refers to the position where the light reflected from the surface of the optical lens closest to the autocollimating optical instrument is formed by the autocollimating optical instrument.

[0064] The position of the optical reference refers to the position formed by the light reflected from the surface of the optical reference closest to the autocollimating optical instrument.

[0065] The position of an optical lens relative to an optical reference refers to the difference between the positions of the optical lens and the optical reference in an autocollimating optical instrument.

[0066] The offset of the optical lens relative to the optical reference position is the difference between the optical lens position relative to the optical reference position recorded twice, before and after the test platform experiences the load.

[0067] A preferred method for anti-loosening process parameters of screws in airborne optical machinery products includes the following steps:

[0068] Step 1: Identify the influencing factors related to the anti-loosening of screw 4.

[0069] Determine the process parameters related to screw loosening prevention, and group the process parameters according to the test method of orthogonal experiment.

[0070] Three factors affecting the anti-loosening performance of screws were selected: spring washer material, tightening torque, and thread engagement length. Different levels were set for each factor.

[0071] Adding spring washers or applying adhesive is one of the anti-loosening techniques.

[0072] The selected spring washer material, tightening torque, and thread engagement length are each numbered.

[0073] The influencing factors, spring washer material A, tightening torque B, and thread engagement length C, were combined at different levels according to the orthogonal test method. Each combination is a process parameter.

[0074] For example:

[0075] Stainless steel spring washers are numbered A1, high-strength stainless steel spring washers are numbered A2, and 65Mn spring washers are numbered A3.

[0076] Tightening torque of 0.6 Nm is designated as B1, tightening torque of 0.7 Nm is designated as B2, and tightening torque of 0.8 Nm is designated as B3;

[0077] The thread engagement length of 3.7mm is designated as C1, the thread engagement length of 5.7mm is designated as C2, and the thread engagement length of 7.7mm is designated as C3.

[0078] The different levels of influencing factors were combined according to the orthogonal experimental method, and each combination was a process parameter. The groupings are shown in Table 1.

[0079] Table 1. Screw Anti-loosening Process Parameter Grouping and Data Recording Table

[0080]

[0081] Step 2, acquire the position of optical reference 1

[0082] The optical reference 1 and platform 3 are stabilized.

[0083] The position of optical reference 1 is acquired using autocollimating optical instrument 5, in the format (x, y), and recorded in the column corresponding to "Position of optical reference 1" in Table 1.

[0084] Step 3: Collect the position of each group of optical lenses 2.

[0085] Using the process parameters determined in step 1 for each combination, screws 4 and spring washers are used to install the optical lenses 2 onto the screw holes 33. During installation, the lenses are fixed onto the test platform 3 in order of distance from the autocollimating optical instrument 5, from farthest to near, and the initial positions of the optical lenses 2 are recorded sequentially.

[0086] Each set of optical lenses corresponds to a set of process parameters.

[0087] Step 4, Apply environmental loads

[0088] After installation, the test platform is mounted on the vibration table, and vibration load is applied to the test platform according to the required vibration level and time.

[0089] The test platform was removed from the vibration platform and placed in a temperature shock chamber. Temperature cycling was performed within the temperature range of -55℃ to 70℃, with a temperature change rate of 3℃ / min, for a total of 8 cycles.

[0090] Step 5: Collect the positions of optical reference 1 and each group of optical lenses 2 after unloading.

[0091] Remove environmental loads.

[0092] The positions of each optical lens 2 are recorded sequentially using an autocollimating optical instrument 5.

[0093] Multiple sets of optical lenses 2 are removed in sequence from near to far from the autocollimating optical instrument 5. Before removal, the position of each optical lens 2 is recorded sequentially using the autocollimating optical instrument 5. After all lenses are removed, the position of the optical reference 1 is recorded.

[0094] Step 6, Calculate the offset

[0095] Based on the changes in position of each optical lens 2 before and after the application of environmental load, the data is processed according to the data processing method of orthogonal test to obtain the offset of each optical lens 2 relative to optical reference 1.

[0096] Step 7, Selecting the optimal process parameters

[0097] Based on the offset corresponding to each set of process parameters, the set of process parameters with the smallest offset relative to the optical reference position can be selected, or multiple sets of process parameters that meet the product requirements can be selected.

[0098] The optical lens 2 can be any type of component that can reflect light, such as a lens, a mirror, or a prism.

[0099] The principle of a method for optimizing anti-loosening process parameters for airborne optical machinery products is as follows:

[0100] The effectiveness of an anti-loosening method is determined by the offset of the fixed optical lens relative to an optical reference before and after a load is applied. Specifically, the part with the optical lens is fixed to a test platform according to selected process parameters. A reflector serves as the optical reference at one end of the test platform, and an autocollimating optical instrument is placed at the other end. Light emitted from the optical instrument shines on the reflector, and some or all of the light is reflected onto the receiving screen of the autocollimating optical instrument. The optical lens is then installed on the test platform using screws, fixed according to the selected process parameters. The positions of the optical lens and the optical reference are recorded. The assembled test platform is then placed under the environmental load to be tested, and the positions of the optical lens and the optical reference are recorded after the environmental load is applied. The offset of the optical lens relative to the optical reference before and after the load is applied is used to determine the anti-loosening effect of the screws.

Claims

1. An on-board optical machine product screw anti-loosening process parameter optimization method, characterized in that, The device comprises an optical reference (1), a platform (3), a self-collimation optical instrument (5), and a loading instrument. The optical reference (1) is fixed on the platform (3) and can be arranged in parallel side by side. The optical reference (1) and the self-collimation optical instrument (5) are respectively located at the two ends of the platform (3). The optical reference (1) is a mirror, which is fixed to the platform (3) through the optical reference interface (31). The screw hole (33) is matched with the screw (4) to fix the optical lens (2). The flatness of the mirror is not less than 0.5λ@632.8nm, and the reflectivity is not less than 99%. The loading instrument comprises a vibration table and a temperature impact box. The vibration table is fixed to the platform interface (32), and the platform (3) is fixed to the vibration table through the platform interface (32). The temperature impact box is placed outside the platform (3), i.e., the platform (3) and the selected airborne optical instrument screw are placed in the temperature impact box. The temperature change range of the temperature impact box is -60℃-90℃, and the temperature change rate is not greater than 3℃ / min. The frequency range of the vibration table is 0-2000Hz, and the load is not less than 50Kg. The parameter optimization method comprises the following steps: Step 1: determining the factors related to the screw (4) locking The spring washer or glue coating is used as one of the locking processes to determine the process parameters related to the screw locking. Three factors affecting the screw locking performance are selected, i.e., spring washer material, tightening torque, and thread length. The selected spring washer material, tightening torque, and thread length are numbered. According to the orthogonal test method, the different levels of the spring washer material A, tightening torque B, and thread length C are combined, and each combination is a process parameter. Step 2: collecting the position of the optical reference (1) The optical reference (1) and the platform (3) are stabilized. The position of the optical reference (1) is collected by the self-collimation optical instrument (5) and recorded as (x, y). Step 3: collecting the position of each optical lens (2) According to the process parameters of each combination determined in step 1, the optical lens (2) is respectively installed on the screw hole (33) by using the screw (4) and the spring washer; during installation, the optical lens (2) is fixed on the test platform (3) in order from far to near to the autocollimator (5), and the initial position of the optical lens (2) is recorded in order; Each group of optical lenses (2) corresponds to a group of process parameters; Step 4, apply environmental load: After the installation of the test platform is completed, the test platform is installed on the vibration table, and the vibration load is applied to the test platform according to the required vibration level and time; The test platform is removed from the vibration platform and placed in the temperature shock box, and temperature cycling is performed in the temperature range of-55℃ to 70℃, with a temperature change rate of 3℃ / min, for a total of 8 cycles; Step 5, collect the positions of the optical reference (1) and each group of optical lenses (2) after unloading: Remove the environmental load; The positions of each optical lens (2) are recorded in order by the autocollimator (5); The multiple groups of optical lenses (2) are removed in order from near to far to the autocollimator (5), and the positions of each optical lens (2) are recorded in order by the autocollimator (5) before removal, and the position of the optical reference (1) is recorded after all are removed; Step 6, calculate the offset: According to the change in the position of the optical reference (1) and each group of optical lenses (2) before and after the environmental load is applied, the data is processed according to the data processing method of orthogonal test to obtain the offset of each group of optical lenses (2) relative to the optical reference (1); Step 7, select the optimal process parameters: According to the offset corresponding to each group of process parameters, the group of process parameters with the smallest offset of the optical lens (2) relative to the optical reference (1) can be selected, or multiple groups of process parameters that meet the product requirements can be selected.

2. The method of claim 1, wherein the method is performed on a photomask product, and the method further comprises: providing a photomask product; and performing the method on the photomask product. The mirror is made of flat optical glass.

3. The method of claim 1, wherein the method is performed on a photomask product, and the method further comprises: providing a photomask product; and performing the method on the photomask product. The mirror is made of a prism.

4. The method of claim 1, wherein the method is performed on a photomask product, and the method further comprises: providing a photomask product; and performing the method on the photomask product. The mirror is a reflective film sintered on a metal substrate.

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