Machining method for precise optical mounting window

Abstract

The invention belongs to the technical field of aerospace machinery precision manufacturing, particularly relates to a machining method of a precision optical mounting window, and optimizes machining of the precision optical mounting window based on tool design, optical mounting window machining and rapid detection of the profile tolerance of the optical mounting window. Wherein during gypsum filling, the gypsum filling amount at the top of the tool is minimized; in the trial cutting correction process, the step of correcting the machining original point of the part is configured when the part is clamped again. The method can solve the problems that the precision optical mounting window is easy to deform during processing, the processing qualification rate is low, and precision contour detection depends on three-coordinate equipment, and has very high application and popularization values.

Description

Technical Field

[0001] The invention belongs to the technical field of precision manufacturing of aerospace machinery, and in particular relates to a mechanical processing method for a precision optical mounting window. Background Art

[0002] As new fighters have higher and higher requirements for weight reduction and stealth performance, aircraft structural parts are also moving towards lightweight and high precision. The lightweight of parts will inevitably lead to a large amount of material removal, weakened rigidity of parts, and easy deformation during machining, resulting in part tolerance; the precision of parts is getting higher and higher, especially the precision requirements for optical parts installation windows are getting higher and higher, which will inevitably lead to a significant increase in the difficulty of part processing and inspection.

[0003] Taking a certain type of product as an example, the structural parts involved in stealth performance are typical large-sized weak rigid skeleton parts. The parts are very easy to deform during clamping and processing, and the parts are made of difficult-to-process cast titanium alloy materials. The tool wear is serious during processing, and the accuracy is difficult to guarantee. There are multiple optical installation windows symmetrically distributed on the upper end of the part. Since it is necessary to provide installation and positioning references for optical parts, the contour of the optical installation window is required to be -0.03mm~+0.02mm. Affected by factors such as residual stress, processing deformation, clamping and positioning, the contour pass rate of the optical installation window is extremely low. In addition, the contour of the part needs to be detected using a three-coordinate device, which is highly dependent on the three-coordinate device, lengthens the processing cycle of the part, causes a long waiting time for the equipment, and is not conducive to the promotion of the processing method.

[0004] Therefore, there is an urgent need for a stable and precise optical mounting window machining and rapid detection method to ensure stable and efficient machining of the optical mounting window, ensure the machining qualification rate, and shorten the machining cycle of the structural parts. Summary of the invention

[0005] In view of this, the present invention provides a mechanical processing method for a precision optical mounting window, which can solve the problems of easy deformation of the precision optical mounting window during processing, low processing qualification rate, and dependence of precision contour detection on three-coordinate equipment, and has high application and promotion value.

[0006] The technical solution of the present invention is:

[0007] A method for machining a precision optical mounting window, comprising:

[0008] Residual stress removal: inserting a heat treatment process for the entire part in a timely manner during the processing of the installation window, controlling the heat treatment parameters, and releasing the residual stress of the part;

[0009] Tooling design: Auxiliary support tooling is provided to support the parts during machining; the tooling is based on aluminum alloy and the top is filled with gypsum, and the parts are in contact with the gypsum during support;

[0010] Optical installation window processing: Setting a molded dovetail cutter to machine the part from the outer cavity, and completing the processing of the window contour in one feed; setting an allowance value before the final finishing of the part to achieve trial cutting correction;

[0011] Rapid detection of optical installation window contour: During the trial cutting and correction process, a check fixture is used to quickly detect the parts. The check fixture is used to completely simulate the matching state between the optical parts and the parts. During the rapid detection process, the contour accuracy is converted into dimensional accuracy based on the detection results of the check fixture.

[0012] Wherein: when filling the gypsum, the amount of gypsum filled on the top of the tooling is minimized; during the trial cutting and correction process, a step of calibrating the processing origin of the part is configured when clamping again.

[0013] Furthermore, the specific method of removing residual stress is:

[0014] First, the parts are processed to leave a margin of no more than 2mm, and then the titanium alloy is vacuum annealed to remove the stress of the parts. The heat treatment parameters are: heating temperature 400~600℃, holding time 2~3h, working vacuum degree ≤8×10 -2 Pa;

[0015] After that, the optical installation window and features with precision requirements are processed to size, leaving a margin of 0.3-0.6mm, and the titanium alloy is subjected to high and low temperature aging heat treatment. The heat treatment parameters are: low temperature -40 to -60℃ for 1 to 2h, high temperature 90 to 110℃ for 1 to 2h, and low temperature followed by high temperature for a total of no less than 3 cycles.

[0016] Furthermore, the tooling is a contour tooling designed according to the part structure, and the specific process of designing the tooling is as follows:

[0017] The inclined angle of the upper surface support surface of the tooling is designed according to the angle between the ribs between the windows and the installation reference surface, so that the distance between the upper surface support surface and the supported surface of the part is consistent; the upper surface support surface of the tooling is evenly distributed with a stepped structure to improve the bonding between the gypsum and the tooling;

[0018] The bottom surface of the tooling is arranged as a waist-shaped through hole, and screws are passed through the waist-shaped through hole to connect with the workbench. The tooling adjusts the distance between the upper surface support surface and the part by linear movement on the workbench.

[0019] Furthermore, the specific method of filling the tool with plaster comprises the following steps:

[0020] S101: Clean the tooling and parts before filling the plaster, and stir the plaster evenly;

[0021] S102: Move the tooling to ensure that the distance between the ribs on the upper surface of the tooling and the window is less than 20 mm;

[0022] S103: Plaster is evenly filled at least two positions on the upper surface support surface, the width of the plaster support area is limited to within 12 mm, and the filling length of a single plaster filling point is 0.2 to 0.3 times the length of the rib; the optical installation window processing part is not filled with plaster;

[0023] S104: After the plaster is completely dry, start machining the parts.

[0024] Furthermore, the processing method of the optical mounting window is:

[0025] Design a contoured dovetail cutter according to the shape of the optical installation window, and the angle of the dovetail cutter is consistent with the angle of the installation window; select dovetail cutters of different specifications according to different processing procedures, use a large-diameter dovetail cutter with a diameter of 18-22mm for large-residue processing, and use a small-diameter dovetail cutter with a diameter of no more than 10mm for final finishing; consider using the middle part of the dovetail cutter to process the optical installation window when setting the tool, and keep the tool extension as short as possible while ensuring normal processing when clamping the tool;

[0026] The contour of the optical installation window is processed to size using at least three CNC milling processes; the first CNC milling process leaves a 0.3-0.6mm margin, and then the measurement result of the margin is obtained based on the three-coordinate measuring instrument; then the CNC program margin is adjusted according to the measurement result, the part is processed to the upper difference size, and the three-coordinate measurement is performed again. The CNC program is adjusted according to the three-coordinate measurement result, and only the edge where the out-of-tolerance position is located is refined by comparing the second measurement result, and the edge that does not exceed the tolerance is no longer processed until the contour is qualified;

[0027] Among them, the processing parameters for processing using a contoured dovetail cutter with a tool diameter not greater than 10 mm are: spindle speed 1500-2000 r / min, feed speed 250-300 mm / min.

[0028] Furthermore, the specific method of origin correction includes the following steps:

[0029] S201: The part is placed on the tooling through the two pin holes at the front and rear of the part, and screws are passed through the screw holes and tightened to clamp the part on the tooling;

[0030] S202: Take out two pins, align the two pin holes at the front and back, and calibrate the machining coordinate system;

[0031] S203: Use a table to align the pin hole, set the center of the pin hole as the origin of the machine tool processing program, and perform processing on the part.

[0032] Furthermore, the detection method of the optical installation window contour is:

[0033] According to the structure of the optical parts to be matched, the precision inspection fixture of the optical installation window is designed, and the inspection fixture completely simulates the matching state of the optical parts and metal parts;

[0034] After the precision gauge is installed on the window, the profile tolerance is converted into the height difference of the gauge beyond the outer surface of the metal part through trigonometric conversion according to the angle value of the window.

[0035] Beneficial effects of the present invention:

[0036] 1. The present invention provides a complete processing method for processing optical windows of large-sized weak-rigidity frame-type parts, which can stably detect and process the parts and improve the consistency and qualified rate of part processing.

[0037] 2. The present invention designs a set of rigid-flexible auxiliary support tooling, clarifies the principle of gypsum filling, and standardizes the use of the tooling.

[0038] 3. The present invention specifies a mechanical processing method and an origin correction method for an optical mounting window, providing ideas for processing similar structural features.

[0039] 4. The present invention designs a set of window rapid detection methods, which can quickly detect optical windows without using three-coordinate equipment, reduce the dependence of part processing on three-coordinate equipment, and shorten the processing cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 Schematic diagram of the aluminum alloy substrate of the rigid-flexible auxiliary support tooling;

[0042] Figure 2 It is a schematic diagram of the structure of some areas of the parts of the embodiment;

[0043] Figure 3 It is a schematic diagram of a profiled dovetail knife;

[0044] Figure 4 This is a schematic diagram of the principle of the optical installation window precision inspection fixture;

[0045] Among them: 1. Support surface of the upper surface of the tooling; 2. Step-like ladder structure; 3. Waist-shaped through hole; 4. Filling plaster position; 5. Pin hole at the front end of the part (one at the rear end is not shown); 6. Screw hole; 7. Dovetail knife angle; 8. Precision inspection fixture; 9. Metal parts; 10. Glue filling gap; 11. Bottom surface of precision inspection fixture; 12. Outer surface of the part; 13. Height difference. DETAILED DESCRIPTION

[0046] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0047] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0048] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0049] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0050] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0051] In one embodiment of the present invention, a method for machining a precision optical mounting window is provided, comprising:

[0052] Residual stress removal: inserting a heat treatment process for the entire part in a timely manner during the processing of the installation window, controlling the heat treatment parameters, and releasing the residual stress of the part;

[0053] Tooling design: Auxiliary support tooling is provided to support the parts during machining; the tooling is based on aluminum alloy and the top is filled with gypsum, and the parts are in contact with the gypsum during support;

[0054] Optical installation window processing: Setting a molded dovetail cutter to machine the part from the outer cavity, and completing the processing of the window contour in one feed; setting an allowance value before the final finishing of the part to achieve trial cutting correction;

[0055] Rapid detection of optical installation window contour: During the trial cutting and correction process, a check fixture is used to quickly detect the parts. The check fixture is used to completely simulate the matching state between the optical parts and the parts. During the rapid detection process, the contour accuracy is converted into dimensional accuracy based on the detection results of the check fixture.

[0056] Wherein: when filling the gypsum, the amount of gypsum filled on the top of the tooling is minimized; during the trial cutting and correction process, a step of calibrating the processing origin of the part is configured when clamping again.

[0057] In this embodiment, the specific method of removing residual stress is:

[0058] First, the parts are processed to leave a margin of no more than 2mm, and then the titanium alloy is vacuum annealed to remove the stress of the parts. The heat treatment parameters are: heating temperature 400~600℃, holding time 2~3h, working vacuum degree ≤8×10 -2 Pa;

[0059] After that, the optical installation window and features with precision requirements are processed to size, leaving a margin of 0.3-0.6mm, and the titanium alloy is subjected to high and low temperature aging heat treatment. The heat treatment parameters are: low temperature -40 to -60℃ for 1 to 2h, high temperature 90 to 110℃ for 1 to 2h, and low temperature followed by high temperature for a total of no less than 3 cycles.

[0060] In this embodiment, the tooling is a contour tooling designed according to the part structure, and the specific process of designing the tooling is as follows:

[0061] The inclined angle of the upper surface support surface of the tooling is designed according to the angle between the ribs between the windows and the installation reference surface, so that the distance between the upper surface support surface and the supported surface of the part is consistent; the upper surface support surface of the tooling is evenly distributed with a stepped structure to improve the bonding between the gypsum and the tooling;

[0062] The bottom surface of the tooling is arranged as a waist-shaped through hole, and screws are passed through the waist-shaped through hole to connect with the workbench. The tooling adjusts the distance between the upper surface support surface and the part by linear movement on the workbench.

[0063] In this embodiment, the specific method of filling gypsum on the tooling includes the following steps:

[0064] S101: Clean the tooling and parts before filling the plaster, and stir the plaster evenly;

[0065] S102: Move the tooling to ensure that the distance between the ribs on the upper surface of the tooling and the window is less than 20 mm;

[0066] S103: Plaster is evenly filled at least two positions on the upper surface support surface, the width of the plaster support area is limited to within 12 mm, and the filling length of a single plaster filling point is 0.2-0.3 times the length of the rib; the optical installation window processing part is not filled with plaster;

[0067] S104: After the plaster is completely dry, start machining the parts.

[0068] In this embodiment, the processing method of the optical mounting window is:

[0069] Design a contoured dovetail cutter according to the shape of the optical installation window, and the angle of the dovetail cutter is consistent with the angle of the installation window; select dovetail cutters of different specifications according to different processing procedures, use a large-diameter dovetail cutter with a diameter of 18-22mm for large-residue processing, and use a small-diameter dovetail cutter with a diameter of no more than 10mm for final finishing; consider using the middle part of the dovetail cutter to process the optical installation window when setting the tool, and keep the tool extension as short as possible while ensuring normal processing when clamping the tool;

[0070] The contour of the optical installation window is processed to size using at least three CNC milling processes; the first CNC milling process leaves a 0.3-0.6mm margin, and then the measurement result of the margin is obtained based on the three-coordinate measuring instrument; then the CNC program margin is adjusted according to the measurement result, the part is processed to the upper difference size, and the three-coordinate measurement is performed again. The CNC program is adjusted according to the three-coordinate measurement result, and only the edge where the out-of-tolerance position is located is refined by comparing the second measurement result, and the edge that does not exceed the tolerance is no longer processed until the contour is qualified;

[0071] Among them, the processing parameters for processing using a contoured dovetail cutter with a tool diameter not greater than 10 mm are: spindle speed 1500r / min~2000r / min, feed speed 250mm / min~300mm / min.

[0072] In this embodiment, the specific method of origin correction includes the following steps:

[0073] S201: The part is placed on the tooling through the two pin holes at the front and rear of the part, and screws are passed through the screw holes and tightened to clamp the part on the tooling;

[0074] S202: Take out two pins, align the two pin holes at the front and back, and calibrate the machining coordinate system;

[0075] S203: Use a table to align the pin hole, set the center of the pin hole as the origin of the machine tool processing program, and perform processing on the part.

[0076] In this embodiment, the method for detecting the contour of the optical installation window is:

[0077] According to the structure of the optical parts to be matched, the precision inspection fixture of the optical installation window is designed, and the inspection fixture completely simulates the matching state of the optical parts and metal parts;

[0078] After the precision gauge is installed on the window, the profile tolerance is converted into the height difference of the gauge beyond the outer surface of the metal part through trigonometric conversion according to the angle value of the window.

[0079] In this embodiment, see Figure 1-Figure 4 , providing a machining method for a precision optical mounting window, comprising:

[0080] Step 1: Residual stress removal: During the material removal process, the parts will continuously release residual stress, causing deformation of the parts. Insert the heat treatment process in time during the processing, control the heat treatment parameters, and release the residual stress of the parts.

[0081] Step 2: Tooling design: Design a rigid-flexible auxiliary support tooling with an aluminum alloy tooling as the base and gypsum filled on the top to connect with the parts, supporting the parts during machining and improving the overall rigidity of the parts during machining.

[0082] Step 3: Filling with plaster. The plaster filling on the top of the tooling adopts the principle of minimum, strictly controls the amount of plaster, and minimizes deformation caused by plaster expansion.

[0083] Step 4: Processing of optical installation window. Design a molded dovetail cutter to process from the outer cavity, and complete the processing of the window contour in one feed to ensure the continuity of the tool path and facilitate subsequent adjustments. Design the allowance value, measure the optical installation window, analyze the measurement results, and locate the out-of-tolerance parts for fine-tuning.

[0084] Step 5: Check the machining origin. Check the origin after the second clamping to ensure the consistency of the program origin.

[0085] Step 6: Rapid detection of the contour of the optical installation window. Special inspection tools are used to quickly detect parts at the production site. High-precision inspection tools are designed according to the matching optical parts to fully simulate the matching state of optical parts and structural parts, and the contour accuracy is converted into dimensional accuracy, which is convenient for rapid detection on site.

[0086] Specific methods for residual stress removal:

[0087] Due to the limitation of casting process, residual stress is inevitably introduced into the blank during casting. As the residual stress of parts is continuously released, it will cause deformation of parts and affect the size and shape tolerance of parts. In the embodiment, the titanium alloy casting blank of parts usually has a 5-7mm margin. The release of residual stress during the removal process will inevitably cause deformation of parts, and residual stress needs to be eliminated during processing.

[0088] 1) First, the parts are processed to leave a 1mm margin, and the titanium alloy is vacuum annealed to remove stress. Heat treatment parameters: heating temperature 400-600℃, holding time 2-3h, working vacuum degree ≤8×10-2Pa.

[0089] 2) Then, except for the optical installation window and some features with precision requirements, the rest are left with a 0.5mm margin, and the titanium alloy is subjected to high and low temperature aging heat treatment. Heat treatment parameters: low temperature -50℃ treatment and insulation for 1 to 2 hours, high temperature 100℃ treatment and insulation for 1 to 2 hours, low temperature first and high temperature later, a total of 3 cycles. Remove the residual stress of the parts before finishing the optical installation window.

[0090] The specific process of tooling design:

[0091] The tooling is a contoured tooling designed according to the structure of the part. The angle of the inclined surface 1 of the tooling upper surface support surface is designed according to the angle between the ribs between the windows and the installation reference surface. The step-shaped ladder structure 2 is evenly distributed on the upper surface support surface of the part to improve the bonding between the plaster and the tooling. The bottom surface of the tooling is set with a waist-shaped through hole 3, and the screw passes through the waist-shaped through hole to connect with the workbench. The tooling can adjust the distance between the tooling bevel and the part by moving forward and backward.

[0092] Specific method of filling plaster:

[0093] The deformation of parts caused by the expansion of plaster in the actual processing process has a great impact on the contour processing of the final optical part installation surface. The plaster filling adopts the principle of minimum to minimize the deformation caused by the expansion of plaster. The specific operation method is:

[0094] 1) Before filling with plaster, the tooling and parts should be cleaned and the plaster should be stirred evenly.

[0095] 2) Move the tooling to ensure that the distance between the ribs on the upper surface support surface 1 of the tooling and the window is 15 mm.

[0096] 3) Plaster is filled in the top, middle and bottom of the ribs between the windows. The width of the plaster support area is limited to 10mm, and the length of a single plaster filling point should be about 1 / 5 of the rib length. It is strictly forbidden to fill plaster in the processing part of the optical installation window.

[0097] 4) Wait for about 2 hours for the plaster to dry before starting parts processing.

[0098] Optical mounting window processing method:

[0099] 1) Design a contoured dovetail cutter according to the shape of the optical installation window. The angle 7 of the dovetail cutter must be strictly consistent with the angle of the installation window. Select dovetail cutters of different specifications according to different processing procedures. When the allowance is large, in order to improve the cutting efficiency, a large-diameter dovetail cutter with a diameter of about 20 mm is used. In order to reduce the cutting force during the final finishing, the tool diameter must be strictly controlled not to be greater than 10 mm. Considering the stability of the tool during cutting, it is necessary to consider using the middle part of the dovetail cutter to process the optical installation window when setting the tool. When the tool is clamped, the tool extension should be as short as possible while ensuring normal processing.

[0100] 2) The contour of the optical installation window requires at least three CNC milling processes to be processed to size. The first CNC milling process leaves a 0.2mm margin, and then sends it to the three-coordinate measurement to obtain the measurement result of the margin; then adjust the CNC program margin according to the measurement result, process the part to the upper difference size, and perform three-coordinate measurement again; strictly adjust the CNC program according to the three-coordinate measurement result, and compare the second measurement result to only fine-tune the edge where the deviation position is located, and no longer process the edge that does not exceed the deviation until the contour is qualified.

[0101] A contoured dovetail cutter with a tool diameter not greater than 10 mm is used for processing, and the processing parameters are: spindle speed 1500-2000 r / min, feed speed 250-300 mm / min.

[0102] Processing origin correction method:

[0103] The optical window contour needs to be processed and measured multiple times to ensure its pass rate. In the process of multiple rounds of processing and measurement, it is inevitable to perform secondary clamping of parts. Due to the influence of pin positioning error and machine tool repeat positioning accuracy, inaccurate secondary clamping positioning will cause the inability to process to the correct position during fine-tuning according to the measurement results. Therefore, the correction of the processing origin is a key step to ensure the pass rate of the optical installation window contour. The origin correction mainly includes the following steps:

[0104] 1) Place the part on the fixture through the two pin holes 5 at the front and rear, and tighten and clamp the part through the screw holes 6;

[0105] 2) Take out the two pins, align the two pin holes in front and behind, and calibrate the C axis;

[0106] 3) Use a table to locate the pin hole, set the center of the pin hole as the program origin and start processing.

[0107] Optical installation window contour quick detection method:

[0108] The optical window contour needs to be processed and measured many times to ensure its pass rate. Part processing is too dependent on the three-coordinate equipment. When the three-coordinate equipment has a large workload or some manufacturers do not have precision three-coordinate equipment, part processing is restricted. The principle of the optical installation window contour rapid detection method is as follows:

[0109] 1) According to the structure of the optical parts to be matched, design the precision inspection fixture of the optical installation window, which completely simulates the matching state of the optical parts and metal parts.

[0110] 2) Because there is a gap 10 between the optical part and the metal part, the bottom surface 11 of the precision gauge 8 will produce a height difference 13 with the outer surface 12 of the part after the precision gauge 8 and the metal part 9 are matched. In addition, the change of the profile affects the gap between the gauge and the part, which will also cause the change of the height difference 13. According to the angle value of the window, the profile tolerance can be converted into the height difference 13 of the gauge exceeding the outer surface of the metal part through simple trigonometric conversion, and the geometric tolerance that requires three-coordinate measurement can be converted into the dimensional tolerance that can be measured by a micrometer.

[0111] A better embodiment: precision boring and correction of process holes are performed on other process handles, and the processing coordinate system is corrected based on the process holes.

[0112] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for machining a precision optical mounting window, characterized in that: include: Residual stress removal: inserting a heat treatment process for the entire part in a timely manner during the processing of the installation window, controlling the heat treatment parameters, and releasing the residual stress of the part; Tooling design: Auxiliary support tooling is provided to support the parts during machining; the tooling is based on aluminum alloy and the top is filled with gypsum, and the parts are in contact with the gypsum during support; Optical installation window processing: Setting a molded dovetail cutter to machine the part from the outer cavity, and completing the processing of the window contour in one feed; setting an allowance value before the final finishing of the part to achieve trial cutting correction; Rapid detection of optical installation window contour: During the trial cutting and correction process, a check fixture is used to quickly detect the parts. The check fixture is used to completely simulate the matching state between the optical parts and the parts. During the rapid detection process, the contour accuracy is converted into dimensional accuracy based on the detection results of the check fixture. Wherein: when filling the gypsum, the amount of gypsum filled on the top of the tooling is minimized; during the trial cutting and correction process, a step of calibrating the processing origin of the part is configured when clamping again.

2. The machining method of the precision optical mounting window according to claim 1, characterized in that: The specific methods for removing residual stress are: First, the parts are processed to leave a margin of no more than 2mm, and then the titanium alloy is vacuum annealed to remove the stress of the parts. The heat treatment parameters are: heating temperature 400~600℃, holding time 2~3h, working vacuum degree ≤8×10 -2 Pa; After that, the optical installation window and features with precision requirements are processed to size, leaving a margin of 0.3 to 0.6 mm, and the titanium alloy is subjected to high and low temperature aging heat treatment. The heat treatment parameters are: low temperature -40 to -60℃ for 1 to 2 hours, high temperature 90-110℃ for 1 to 2 hours, and low temperature followed by high temperature for a total of no less than 3 cycles.

3. The machining method of the precision optical mounting window according to claim 2, characterized in that: The tooling is a profiling tooling designed according to the part structure, and the specific process of designing the tooling is as follows: The inclined angle of the upper surface support surface of the tooling is designed according to the angle between the ribs between the windows and the installation reference surface, so that the distance between the upper surface support surface and the supported surface of the part is consistent; the upper surface support surface of the tooling is evenly distributed with a stepped structure to improve the bonding between the gypsum and the tooling; The bottom surface of the tooling is arranged as a waist-shaped through hole, and screws are passed through the waist-shaped through hole to connect with the workbench. The tooling adjusts the distance between the upper surface support surface and the part by linear movement on the workbench.

4. The machining method of the precision optical mounting window according to claim 3, characterized in that: The specific method of filling the tooling with plaster includes the following steps: S101: Clean the tooling and parts before filling the plaster, and stir the plaster evenly; S102: Move the tooling to ensure that the distance between the ribs on the upper surface of the tooling and the window is less than 20 mm; S103: Plaster is evenly filled at least two positions on the upper surface support surface, the width of the plaster support area is limited to within 12 mm, and the filling length of a single plaster filling point is 0.2 to 0.3 times the length of the rib; the optical installation window processing part is not filled with plaster; S104: After the plaster is completely dry, start machining the parts.

5. The machining method of the precision optical mounting window according to claim 4, characterized in that: The processing method of the optical mounting window is: Design a contoured dovetail cutter according to the shape of the optical installation window, and the angle of the dovetail cutter is consistent with the angle of the installation window; select dovetail cutters of different specifications according to different processing procedures, use a large-diameter dovetail cutter with a diameter of 18 to 22 mm for large excess processing, and a small-diameter dovetail cutter with a diameter of no more than 10 mm for final finishing; consider using the middle part of the dovetail cutter to process the optical installation window when setting the tool, and keep the tool extension as short as possible while ensuring normal processing when clamping the tool; The contour of the optical installation window is processed to size using at least three CNC milling processes; the first CNC milling process leaves a 0.3-0.6mm margin, and then the measurement result of the margin is obtained based on the three-coordinate measuring instrument; then the CNC program margin is adjusted according to the measurement result, the part is processed to the upper difference size, and the three-coordinate measurement is performed again. The CNC program is adjusted according to the three-coordinate measurement result, and only the edge where the out-of-tolerance position is located is refined by comparing the second measurement result, and the edge that does not exceed the tolerance is no longer processed until the contour is qualified; Among them, the processing parameters for processing using a contoured dovetail cutter with a tool diameter not greater than 10 mm are: spindle speed 1500-2000 r / min, feed speed 250-300 mm / min.

6. The machining method of the precision optical mounting window according to claim 5, characterized in that: The specific method of origin correction includes the following steps: S201: The part is placed on the tooling through the two pin holes at the front and rear of the part, and screws are passed through the screw holes and tightened to clamp the part on the tooling; S202: Take out two pins, align the two pin holes at the front and back, and calibrate the machining coordinate system; S203: Use a table to align the pin hole, set the center of the pin hole as the origin of the machine tool processing program, and perform processing on the part.

7. The machining method of the precision optical mounting window according to claim 6, characterized in that: The detection method of the optical installation window profile is: According to the structure of the optical parts to be matched, the precision inspection fixture of the optical installation window is designed, and the inspection fixture completely simulates the matching state of the optical parts and metal parts; After the precision gauge is installed on the window, the profile tolerance is converted into the height difference of the gauge beyond the outer surface of the metal part through trigonometric conversion according to the angle value of the window.

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