E-type mirror thin-wall finishing method after slotting

Abstract

This invention discloses a method for thin-walled precision machining of E-type mirrors after grooving, comprising the following steps: Step S1, designing and machining a special fixture for chemical etching of E-type mirrors; Step S2, placing the grooved E-type mirrors one by one into the elliptical hollow areas within the fixture for chemical etching; Step S3, calculating the amount of material removed by polishing; Step S4, preparing a special polishing bit, immersing the bit with wool at the front end in polishing bitumen, allowing it to fully absorb the bitumen and then allowing it to cool, and machining a reservoir on the end face of the bitumen; Step S5, installing the E-type mirrors to be polished and the bitumen on a polishing device, aligning the bitumen with the annular groove of the E-type mirror, adding polishing fluid, setting relevant parameters, and removing the E-type mirrors after polishing for cleaning and drying. The method of this invention requires less reliance on high-precision CNC equipment, has higher production efficiency, and produces E-type mirrors with better thin-walled shape and position accuracy and a very shallow surface damage layer, which can better meet the stringent requirements of laser gyroscopes for the processing quality of E-type mirrors.

Description

Technical Field

[0001] This invention relates to the field of laser gyroscope optical component processing technology, and in particular to a method for thin-walled precision machining of an E-type mirror after slotting. Background Technology

[0002] A laser gyroscope resonant cavity is essentially a ring laser, mainly composed of a cavity body, four mirrors, and anode and cathode, forming a closed ring cavity. The E-type mirror is one type of mirror, typically made of low-expansion, hard, and brittle materials such as quartz glass or microcrystalline glass, and its shape is similar to the letter "E" (e.g.,...). Figure 1 It features a double-sided annular groove and thin-walled structure, with the working surface (also known as the front) coated with a high-precision reflective film.

[0003] During the operation of the resonant cavity, the central pillar of the E-type mirror needs to undergo continuous micro-displacement to compensate for changes in the cavity length under different environments and maintain the stability of the cavity length. Therefore, high requirements are placed on the strength of the thin wall. Secondly, in order to improve the long-term reliability of the laser gyroscope, the resonant cavity also needs to have an extremely low leakage rate. However, the thin wall of the E-type mirror is often a weak point where gas leakage can occur. Therefore, it is required to minimize the micro-cracks in the thin wall during the processing stage to eliminate the risk of gas leakage. In addition, the thin wall also needs to be polished during the resonant cavity assembly and adjustment process to observe the cleanliness of the cavity and the effect of the photoresist.

[0004] Currently, the general processing route for E-type mirrors is: grooving with a hard diamond grinding head (rough machining) — CNC or manual polishing with a soft polyurethane / wool grinding head (finish machining) — ultra-smooth polishing of the working surface — coating. E-type mirrors are made of hard and brittle glass, and a deep damage layer inevitably remains after grooving. While manual polishing effectively removes this damage layer, its precision is difficult to control and its efficiency is extremely low. Compared to manual polishing, CNC polishing with a soft grinding head significantly improves processing efficiency, but it is still a grinding process. Therefore, a noticeable subsurface defect layer remains on the polished surface, and the regular grinding marks are not conducive to improving the strength of thin walls and eliminating the risk of air leakage. Furthermore, the deep damage layer after grooving generally requires a large amount of material to be removed during polishing. Soft grinding heads are easily deformed under stress (polyurethane grinding heads are relatively harder and deform less, but inevitably have a worse polishing effect and a deeper residual damage layer), resulting in a significant deterioration in the flatness and other dimensional accuracy of the thin wall after polishing. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the deficiencies in existing technologies by providing a thin-walled finishing method for E-type mirrors after grooving. This method is used for removing the thin-walled damage layer and polishing the E-type mirror after grooving. This method requires less reliance on high-precision CNC equipment, has higher production efficiency, and produces E-type mirrors with better form and position accuracy and extremely shallow surface damage layers, thus better meeting the stringent quality requirements of laser gyroscopes for E-type mirror processing.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] This invention provides a method for finishing thin-walled surfaces of E-type mirrors after grooving, used to remove and polish the thin-walled damaged layer after grooving of the E-type mirror. The method includes the following steps:

[0008] Step S1: Design and fabricate a special fixture for chemical etching of E-type mirrors. The fixture has multiple elliptical cutouts of the same size.

[0009] Step S2: Place the grooved E-type mirrors one by one into the elliptical hollows in the fixture, immerse the fixture in the prepared etching solution, and control the amount of etching removal by adjusting the time and temperature.

[0010] Step S3: After etching, test the roughness of the thin wall of the double-sided annular groove of the E-type mirror and the parallelism difference between the thin wall and the polishing reference surface, and calculate the sum of the two as the polishing removal amount.

[0011] Step S4: Prepare a special polishing asphalt grinding head. Immerse the grinding head with wool at the front end in polishing asphalt. After the grinding head has fully absorbed the polishing asphalt, let it stand and cool. Then, process a liquid storage tank on the end face of the grinding head.

[0012] Step S5: Install the E-type mirror to be polished and the grinding head on the polishing equipment, align the grinding head with the annular groove of the E-type mirror, add polishing liquid, and set the rotation speed of the E-type mirror and the rotation speed of the grinding head. Control the contact between the grinding head and the thin wall of the annular groove. Based on the pressure between the grinding head and the thin wall of the annular groove and the polishing removal rate under the processing parameters, combined with the calculated polishing removal amount, adjust the polishing time. Take out the polished E-type mirror for cleaning and drying.

[0013] Furthermore, the E-type mirror chemical etching fixture in step S1 of the present invention includes: a part tray and a handle. The part tray has multiple elliptical cutouts of the same size. The elliptical cutouts are used to suspend the E-type mirror vertically in the etching process. Only the outer chamfer of the E-type mirror contacts the fixture.

[0014] Furthermore, the E-type mirror chemical etching fixture in step S1 of the present invention is made of fluoroplastic material, the fixture is circular, and the handle is installed at the center of the circle.

[0015] Furthermore, the method of step S2 of the present invention specifically includes:

[0016] After grooving, the E-type mirrors are placed in batches in the elliptical cutouts of the fixture and immersed in the prepared etching solution. The etching removal amount is controlled by adjusting the time and temperature. The etching removal amount exceeds the depth of the grooved damage layer. The etched E-type mirrors are then rinsed and washed with deionized water 3 to 5 times and then blow-dried or oven-dried.

[0017] Furthermore, the polishing-specific asphalt grinding head in step S4 of the present invention includes: a grinding head base, a grinding head wool portion, and a liquid storage tank. The grinding head base is columnar, and the grinding head wool portion is provided at its bottom. After the grinding head wool portion absorbs polishing asphalt and cools, a liquid storage tank is opened on the end face of the bottom. The liquid storage tank is a "cross" V-shaped groove.

[0018] Furthermore, the method of step S4 of the present invention specifically includes:

[0019] Step S41: Heat the prepared polishing asphalt to 200-300℃ and stir it evenly. At this time, the polishing asphalt is in a molten state and there is smoke evaporating from the liquid surface.

[0020] Step S42: Vertically immerse the wool part of the polishing-specific asphalt grinding head into the molten polishing asphalt for 30-60 seconds;

[0021] Step S43: Remove the grinding head from the molten polishing asphalt and suspend it 10-30 mm above the surface of the polishing asphalt for 5-10 seconds until the wool part of the grinding head fully absorbs the polishing asphalt droplets adsorbed on the surface. Place it with the end face down on a stainless steel or glass plate and let it cool.

[0022] Step S44: Machining a liquid storage tank on the end face of the grinding head using manual or CNC methods, for later use.

[0023] Furthermore, the weight ratio of each component of the polishing asphalt of the present invention is as follows: asphalt: rosin: beeswax = 35-60: 40-60: 0.5-2.

[0024] Furthermore, the method in step S42 of the present invention further includes:

[0025] The diameter of the grinding head is 2 / 3 to 1 times larger than the radial dimension of the single-sided annular groove, and the height of the wool portion of the grinding head is greater than the depth of the annular groove on either side.

[0026] Furthermore, the method of step S5 of the present invention specifically includes:

[0027] Step S51: Install the E-type mirror to be polished and the grinding head on the polishing equipment, with the E-type mirror lying flat;

[0028] Step S52: Tool setting, confirm the position of the grinding head, align the grinding head with the annular groove of the E-type mirror, and use the diamond turning tool provided with the polishing equipment to remove the burrs on the end face and outer circle of the grinding head.

[0029] Step S53: Add polishing liquid until the annular groove is full;

[0030] Step S54: Set the rotation speed of the E-type mirror to 10-30 r / min and the rotation speed of the grinding head to 60-200 r / min; according to the diameter of the grinding head and the radial dimension of the annular groove, set the lateral displacement amplitude of the grinding head to polish the entire thin-walled area of ​​the annular groove, and control the displacement rate to 0.1-0.3 mm / min.

[0031] Step S55: Control the grinding head to move down and contact the thin wall of the annular groove, and continue to move down slowly until the pressure display shows 1 to 2 bar;

[0032] Step S56: Based on the polishing removal rate under pressure and processing parameters and the calculated polishing removal amount, adjust the polishing time to 10-30 minutes until thin-wall polishing is completed;

[0033] Step S57: Remove the E-type mirror, clean it, and replace the annular groove on the other side. Repeat steps S51 to S56.

[0034] Step S58: Clean, dry, and check the thin-wall polishing effect of the E-type mirror.

[0035] Furthermore, the polishing liquid of the present invention is a mixture of ordinary cerium oxide polishing powder and water.

[0036] The beneficial effects of this invention are:

[0037] The present invention proposes a method for thin-wall finishing of E-type laser gyroscope mirror after grooving. The method involves sequentially using chemical etching and CNC polishing with an asphalt / wool grinding head to treat the thin wall after grooving, thereby removing the damaged layer generated by grooving and achieving a polishing effect.

[0038] ① Chemical etching: This method uses an etching solution containing hydrofluoric acid to etch the grooved E-type mirror, removing the damaged layer from the groove. A dedicated etching fixture is designed to achieve batch processing and ensure uniform etching. Compared with traditional polishing methods, this method is extremely efficient, does not rely on CNC equipment, has low cost, and is a stress-free processing method that does not generate new processing stress or damaged layers.

[0039] ② Improved soft grinding head polishing: This polishing step does not need to remove the damaged layer caused by grooving, but mainly polishes the rough surface after chemical etching.

[0040] By designing appropriately sized wool grinding heads and incorporating molten polishing bitumen and performing end-face grooving, the quality of CNC polishing is improved. Bitumen is commonly used in the production of polishing molds for classic polishing, resulting in excellent polishing effects. When the soft grinding head absorbs the polishing bitumen, it fully combines the advantages of both, overcoming the disadvantage of ordinary wool soft grinding heads being easily deformed under pressure. This ensures uniform stress on the end face during the polishing process, maintaining good shape retention. Furthermore, the bitumen itself has a certain degree of viscoelasticity, and with wool fibers as the skeleton, it is less prone to brittle fracture under stress. During polishing, polishing powder is evenly embedded on the bitumen surface, forming numerous cutting edges. The end-face grooving helps to store polishing fluid and improves the fluid flow between the grinding head and the thin-walled contact surface, enhancing the polishing effect while providing excellent cooling, effectively inhibiting thermal creep of the grinding head. With proper rotation and pressure control, the required polishing effect can be achieved in a short time with a small amount of material removed, compensating for the poor surface roughness of chemical etching and reducing the time required for precision CNC equipment. Thanks to the improved grinding head polishing process and smaller material removal, compared to traditional polishing processes, the part's shape and position accuracy are better, and the residual damage layer is shallower. Attached Figure Description

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0042] Figure 1 This is a schematic diagram of the E-type mirror according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of chemical etching of the E-type mirror according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of a wool grinding head soaked in asphalt according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the "cross" V-shaped liquid storage groove on the end face of the grinding head according to an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the front annular groove polishing of an embodiment of the present invention;

[0047] In the diagram, 1-E-type mirror, 2-clamp, 201-handle, 202-parts tray, 203-elliptical cutout, 3-grinding head, 301-grinding head base, 302-grinding head wool part, 303-polishing asphalt. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] Example 1

[0050] The thin-wall finishing method for E-type mirrors after grooving according to an embodiment of the present invention includes the following steps:

[0051] Step S1: Design and fabricate a special fixture for chemical etching of E-type mirrors (such as...) Figure 2 ).

[0052] The E-type mirror chemical etching fixture is made of fluoroplastic and consists of a part tray and a handle. The surface of the part tray is perforated, with each perforation being an ellipse of uniform size, used to hold the E-type mirror to be etched. During etching, the E-type mirror is suspended vertically (with the annular groove axis horizontal) in the perforations, with only the outer chamfer in contact with the fixture. The double-sided annular groove, outer circle, working surface, and back side are all exposed without obstruction, ensuring smooth flow of the etching solution and preventing air bubbles generated during etching from adhering to the thin-walled surface, thus improving etching uniformity.

[0053] Step S2: Chemical etching.

[0054] After grooving, the E-type mirrors are placed in batches at the cutouts of a special fixture and immersed in the prepared etching solution. The etching removal amount is controlled by adjusting the time and temperature. The etching removal amount must exceed the depth of the grooved damage layer. The etched E-type mirrors are then rinsed and washed 3-5 times with deionized water and dried by blowing or baking.

[0055] Step S3: Calculate the amount removed by polishing.

[0056] After etching, the roughness of the thin wall of the double-sided annular groove of the E-type mirror and the parallelism difference between the thin wall and the polishing reference surface (working surface or back surface) are tested respectively, and the sum of the two is the polishing removal amount.

[0057] Step S4: Prepare a special polishing pitch grinding head (e.g.) Figure 3 ).

[0058] ① Heat the prepared polishing asphalt (asphalt: rosin: beeswax = 35~60: 40~60: 0.5~2) to 200~300℃ and stir evenly. At this time, the polishing asphalt is in a molten state and there is smoke evaporating from the liquid surface.

[0059] ② Immerse the pre-made wool grinding head vertically in the molten polishing asphalt for 30-60 seconds.

[0060] Note: The diameter of the grinding head must be 2 / 3 to 1 times larger than the radial dimension of the single-sided annular groove (the difference between the outer and inner diameters of the annular groove), and the height of the wool portion of the grinding head must be greater than the depth of any annular groove.

[0061] ③ Remove the grinding head from the molten polishing asphalt and suspend it 10-30 mm above the surface of the polishing asphalt for 5-10 seconds until the grinding head fully absorbs the polishing asphalt droplets adsorbed on the surface. Place it with the end face down on a stainless steel or glass plate and let it cool.

[0062] ④ Machining a liquid reservoir on the end face of the grinding head using manual or CNC methods (e.g.) Figure 4 ),spare.

[0063] Step S5: Polishing (e.g.) Figure 5 ).

[0064] ① Install the E-type mirror to be polished and the grinding head, with the E-type mirror laid flat.

[0065] ② Set the tool, confirm the position of the grinding head, and use the diamond turning tool that comes with the equipment to remove burrs from the end face and outer circle of the grinding head.

[0066] ③ Add polishing liquid (a mixture of ordinary cerium oxide polishing powder and water) until the annular groove is full.

[0067] ④ Set the rotation speed of the E-type mirror to 10-30 r / min and the rotation speed of the grinding head to 60-200 r / min. Based on the diameter of the grinding head and the radial dimension of the annular groove, set the lateral displacement of the grinding head to be sufficient to polish the entire thin-walled area, and control the displacement rate to 0.1-0.3 mm / min.

[0068] ⑤ Control the grinding head to move down and contact the thin wall of the annular groove, and continue to move down slowly until the pressure display shows 1 to 2 bar.

[0069] ⑥ Based on the polishing removal rate and the calculated polishing removal amount under the pressure and processing parameters, adjust the polishing time to 10-30 minutes to complete the thin-wall polishing.

[0070] ⑦ Remove the E-type mirror, clean it, and replace the annular groove on the other side. Repeat steps ① to ⑥ above.

[0071] ⑧ Clean and dry, then check the polishing effect of the E-type mirror's thin wall. If the removal amount and surface roughness are both acceptable, proceed to the next process; otherwise, readjust the program and rework according to the above steps.

[0072] Note: a) After polishing each E-type mirror, check the condition of the grinding head. If the surface polishing powder is uniform and the grinding head is intact, it can continue to be used; otherwise, replace the grinding head. b) For E-type mirror thin-wall rework, the required polishing time needs to be recalculated based on the size of the thin wall removed (because this polishing process is pressure-controlled rather than displacement-controlled, and the Z-axis displacement has a certain empirical component; to reduce the frequency of rework, the first polishing time can be appropriately increased by about 5% based on the calculated value).

[0073] Example 2

[0074] Step S1: Design and fabricate a special fixture for chemical etching of E-type mirrors (such as...) Figure 2 ).

[0075] Design and manufacture a special fixture for chemical etching of E-type mirrors with a diameter of Ф20*7mm (outer diameter 20mm, thickness 7mm), made of polytetrafluoroethylene (PTFE). After cleaning the grooved E-type mirrors to be etched, place them one by one into the slots of the fixture and gently shake them to ensure stability. Currently, each fixture can hold a maximum of 32 mirrors. Increasing the diameter of the part tray or the number of layers can increase the number of parts that can be placed at one time.

[0076] Step S2: Chemical etching.

[0077] ① Determine the etching removal amount. Using cross-sectional microscopy (destroying the thin wall after grooving and observing the damage layer on the end face with a high-powered microscope), the depth of the residual thin-wall damage layer on the E-type quartz glass sample processed by the current grooving process was detected to be ≤0.033mm. Therefore, the nominal value of the etching removal amount was set at 0.0396mm (0.033mm * 1.2 coefficient), and the tolerance was set at 0~0.005mm.

[0078] ② Slowly immerse the grooved E-type mirror, along with the fixture, in the prepared etching solution (hydrofluoric acid / sulfuric acid / water = 1:1:0.5, V / V) (the etching solution can also be other solvents containing hydrofluoric acid, but the etching rate needs to be calibrated beforehand). Gently agitate the fixture to remove air bubbles from the annular groove. Set the temperature to 75±5℃ and adjust the etching time to 28 minutes (if the etching temperature is lowered, the etching time needs to be extended accordingly, and vice versa). Rinse and rinse the etched E-type mirror 3-5 times with deionized water, and dry at 70℃ for 30 minutes.

[0079] ③ Randomly select ≥3 pieces from each fixture after etching the E-type mirror, and measure the actual amount of material removed by etching as shown in the table below:

[0080]

[0081] As can be seen from the table above, the removal amounts between different parts and the removal amounts of the annular grooves on the front and back sides of the same part after chemical etching are relatively consistent, and all meet the etching removal amount requirement of 0.0396. +0.005 mm, no rework required (if it is lower than the design value, steps ① and ② above can be repeated, and a certain etching time can be added according to the difference in removal amount to meet the requirements).

[0082] 3) Step S3: Calculate the amount removed by polishing.

[0083] At least three E-type mirrors were randomly selected from each batch to test the roughness of the thin wall of the double-sided annular groove and the parallelism difference between the thin wall and the polished reference surface (working surface or back surface), as shown in the table below:

[0084] Sample Sample 1 Sample 2 Sample 3 Average value / μm Front annular groove thin wall roughness Ra / μm 0.379 0.421 0.398 0.399 Backside annular groove thin wall roughness Ra / μm 0.413 0.472 0.432 0.439 Parallelism difference between the front annular groove thin wall and the reference plane / μm 3.72 3.91 3.57 3.73 Parallelism difference between the thin wall of the back annular groove and the reference plane / μm 4.12 3.99 3.53 3.88

[0085] Based on the table above, the polishing removal amount for the front annular groove thin wall is calculated to be 0.399μm + 3.73μm = 4.129μm, and the polishing removal amount for the back annular groove thin wall is calculated to be 0.439μm + 3.88μm = 4.319μm. It can be seen that due to the good consistency of the initial processing technology, the difference in removal amount between the front and back annular groove thin wall polishing is only 4.319μm - 4.129μm = 0.19μm. Taking the larger value of 4.319μm * 1.2, the nominal removal amount required for the next polishing step is 5.183μm, with a tolerance of 0–0.5μm.

[0086] 4) Step S4: Prepare a special polishing pitch grinding head (e.g., Figure 3 ).

[0087] ① Heat the prepared polishing asphalt (asphalt: rosin: beeswax = 50:48:2) to 260℃ and stir well.

[0088] ② The pre-customized wool polishing head (the wool part is Ф3.8*8mm. The deepest annular groove of this Ф20*7mm E-type mirror is <5mm, and the radial dimensions of the single-sided annular groove are 4mm and 4.75mm respectively) is vertically immersed in molten polishing asphalt for 40 seconds.

[0089] ③ Remove the grinding head from the molten polishing asphalt and suspend it about 20 mm above the surface of the polishing asphalt for 5 to 8 seconds until the grinding head fully absorbs the polishing asphalt droplets adsorbed on the surface. Place it on a glass plate with the end face down and let it cool.

[0090] ④ Using a single-edged blade, manually machine a cross-shaped liquid reservoir on the end face of the grinding head (e.g., Figure 4 The groove is V-shaped, with a width of about 0.7 mm and a depth of about 0.7 mm (the size of the V-shaped groove is related to the diameter of the grinding head; the larger the diameter of the grinding head, the wider and deeper the groove can be increased accordingly, generally controlled between 0.5 and 1.2 mm), for later use.

[0091] 5) Step S5: Polishing (e.g.) Figure 5 ).

[0092] ① Install the E-type mirror to be polished and the grinding head on the ring groove polishing machine (PMS precision engraving machine). The E-type mirror is laid flat with the front ring groove facing up.

[0093] ② Set the tool, confirm the position of the grinding head, and use the diamond turning tool that comes with the equipment to finish and remove burrs from the end face and outer circle of the grinding head.

[0094] ③ Add polishing liquid (cerium oxide polishing powder: water = 20-30g: 100ml, mix well) until the annular groove is full.

[0095] ④ Set the rotation speed of the E-type mirror to 20 r / min and the rotation speed of the grinding head to 80 r / min. Set the lateral displacement of the grinding head to 0.1 mm based on the diameter of the grinding head and the radial dimension of the annular groove, so that the entire thin-walled area can be polished, with a displacement rate of 0.1 mm / min.

[0096] ⑤ Control the grinding head to move down and contact the thin wall of the annular groove, and continue to move down slowly until the pressure display shows 1.5 bar.

[0097] ⑥ Based on the pre-calibrated polishing removal rate under this pressure (approximately 0.32 μm / min; this rate needs to be calibrated on the sample beforehand. Generally, the higher the rotation speed and pressure, the higher the polishing rate. However, the pressure must not exceed 2 bar, otherwise the grinding head is prone to deformation, affecting its service life and processing quality) and the calculated polishing removal amount of 5.183... +0.5 μm, set polishing time of 17 minutes to complete the front annular groove thin wall polishing.

[0098] ⑦ Remove the E-type mirror, clean it, and replace the annular groove on the other side. Repeat steps ① to ⑥ above to complete the thin-wall polishing of the annular groove on the back side. During the process, the lateral displacement of the grinding head needs to be adjusted to 0.425 mm, and the polishing time should be modified to 19 min based on this parameter and the polishing removal rate of approximately 0.28 μm / min under pressure.

[0099] ⑧ Clean and dry the E-type mirror, and check the thin-wall polishing effect as shown in the table below:

[0100] Sample Sample 1 Sample 2 Sample 3 Average value / mm Front annular groove thin wall roughness Ra / μm 0.0084 0.0076 0.0077 0.0079 Backside annular groove thin wall roughness Ra / μm 0.0065 0.0071 0.0064 0.0067 Front annular groove thin wall removal amount / μm 5.42 5.37 5.29 5.36 Backside annular groove thin wall removal amount / μm 5.35 5.39 5.21 5.32

[0101] As can be seen from the table above, after one polishing cycle, the roughness of the thin-walled annular grooves on both the front and back sides is less than 0.01 μm, indicating a good polishing effect. The polishing removal amount of the thin-walled annular grooves on both the front and back sides also meets the design value of 5.183. +0.5 μm requirement. Proceed to the next step.

[0102] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0103] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for finishing thin-walled surfaces after grooving an E-type mirror, used to remove and polish the thin-walled damaged layer after grooving an E-type mirror, characterized in that... The method includes the following steps: Step S1: Design and fabricate a special fixture for chemical etching of E-type mirrors. The fixture has multiple elliptical cutouts of the same size. Step S2: Place the grooved E-type mirrors one by one into the elliptical hollows in the fixture, immerse the fixture in the prepared etching solution, and control the amount of etching removal by adjusting the time and temperature. Step S3: After etching, test the roughness of the thin wall of the double-sided annular groove of the E-type mirror and the parallelism difference between the thin wall and the polishing reference surface, and calculate the sum of the two as the polishing removal amount. Step S4: Prepare a special polishing asphalt grinding head. Immerse the grinding head with wool at the front end in polishing asphalt. After the grinding head has fully absorbed the polishing asphalt, let it stand and cool. Then, process a liquid storage tank on the end face of the grinding head. Step S5: Install the E-type mirror to be polished and the grinding head on the polishing equipment, align the grinding head with the annular groove of the E-type mirror, add polishing liquid, and set the rotation speed of the E-type mirror and the rotation speed of the grinding head. Control the contact between the grinding head and the thin wall of the annular groove. Based on the pressure between the grinding head and the thin wall of the annular groove and the polishing removal rate under the processing parameters, combined with the calculated polishing removal amount, adjust the polishing time. Take out the polished E-type mirror for cleaning and drying. The method in step S5 specifically includes: Step S51: Install the E-type mirror to be polished and the grinding head on the polishing equipment, with the E-type mirror lying flat; Step S52: Tool setting, confirm the position of the grinding head, align the grinding head with the annular groove of the E-type mirror, and use the diamond turning tool provided with the polishing equipment to remove the burrs on the end face and outer circle of the grinding head. Step S53: Add polishing liquid until the annular groove is full; Step S54: Set the rotation speed of the E-type mirror to 10-30 r / min and the rotation speed of the grinding head to 60-200 r / min; according to the diameter of the grinding head and the radial dimension of the annular groove, set the lateral displacement amplitude of the grinding head to polish the entire thin-walled area of ​​the annular groove, and control the displacement rate to 0.1-0.3 mm / min. Step S55: Control the grinding head to move down and contact the thin wall of the annular groove, and continue to move down slowly until the pressure display shows 1 to 2 bar; Step S56: Based on the polishing removal rate under pressure and processing parameters and the calculated polishing removal amount, adjust the polishing time to 10-30 minutes until thin-wall polishing is completed; Step S57: Remove the E-type mirror, clean it, and replace the annular groove on the other side. Repeat steps S51 to S56. Step S58: Clean, dry, and check the thin-wall polishing effect of the E-type mirror.

2. The thin-walled finishing method for E-type mirrors after grooving according to claim 1, characterized in that, The E-type mirror chemical etching fixture in step S1 includes a part tray and a handle. The part tray has multiple elliptical cutouts of the same size. The elliptical cutouts are used to suspend the E-type mirror vertically in the etching process. Only the outer chamfer of the E-type mirror contacts the fixture.

3. The thin-walled finishing method for E-type mirrors after grooving according to claim 2, characterized in that, The E-type mirror chemical etching fixture in step S1 is made of fluoroplastic, and the fixture is circular with a handle installed at the center.

4. The thin-walled finishing method for E-type mirrors after grooving according to claim 1, characterized in that, The method in step S2 specifically includes: After grooving, the E-type mirrors are placed in batches in the elliptical cutouts of the fixture and immersed in the prepared etching solution. The etching removal amount is controlled by adjusting the time and temperature. The etching removal amount exceeds the depth of the grooved damage layer. The etched E-type mirrors are then rinsed and washed with deionized water 3 to 5 times and then blow-dried or oven-dried.

5. The thin-walled finishing method for E-type mirrors after grooving according to claim 1, characterized in that, The polishing-specific asphalt grinding head in step S4 includes: a grinding head base, a grinding head wool portion, and a liquid storage tank. The grinding head base is cylindrical, and the grinding head wool portion is provided at its bottom. After the grinding head wool portion absorbs polishing asphalt and cools, a liquid storage tank is opened on the end face of the bottom. The liquid storage tank is a "cross" V-shaped groove.

6. The thin-walled finishing method for E-type mirrors after grooving according to claim 5, characterized in that, The method in step S4 specifically includes: Step S41: Heat the prepared polishing asphalt to 200-300℃ and stir it evenly. At this time, the polishing asphalt is in a molten state and there is smoke evaporating from the liquid surface. Step S42: Vertically immerse the wool part of the polishing-specific asphalt grinding head into the molten polishing asphalt for 30-60 seconds; Step S43: Remove the grinding head from the molten polishing asphalt and suspend it 10-30 mm above the surface of the polishing asphalt for 5-10 seconds until the wool part of the grinding head fully absorbs the polishing asphalt droplets adsorbed on the surface. Place it with the end face down on a stainless steel or glass plate and let it cool. Step S44: Machining a liquid storage tank on the end face of the grinding head using manual or CNC methods, for later use.

7. The thin-walled finishing method for E-type mirrors after grooving according to claim 6, characterized in that, The weight ratio of each component of the polishing asphalt is: asphalt: rosin: beeswax = 35~60: 40~60: 0.5~2.

8. The thin-walled finishing method for E-type mirrors after grooving according to claim 6, characterized in that, The method in step S42 further includes: The diameter of the grinding head is 2 / 3 to 1 times larger than the radial dimension of the single-sided annular groove, and the height of the wool portion of the grinding head is greater than the depth of the annular groove on either side.

9. The thin-walled finishing method for E-type mirrors after grooving according to claim 1, characterized in that, The polishing fluid is a mixture of ordinary cerium oxide polishing powder and water.

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