CN-117300862-B - Thin-wall finish machining method for E-shaped mirror after grooving

CN117300862BCN 117300862 BCN117300862 BCN 117300862BCN-117300862-B

Abstract

The invention discloses a thin-wall finish machining method for E-shaped mirrors after slotting, which comprises the following steps of S1 designing and machining a special chemical etching clamp for the E-shaped mirrors, S2 placing the E-shaped mirrors after slotting in elliptical hollow parts in the clamp one by one for chemical etching, S3 calculating polishing removal amount, S4 preparing a special asphalt grinding head for polishing, immersing the grinding head with wool at the front end in polishing asphalt, standing and cooling after the grinding head fully absorbs the polishing asphalt, machining a liquid storage tank on the end face of the grinding head, S5 installing the E-shaped mirrors to be polished and the grinding head on polishing equipment, aligning the grinding head with ring grooves of the E-shaped mirrors, dripping polishing liquid, setting related parameters, and taking out the E-shaped mirrors for cleaning and blow-drying after polishing. The method of the invention has less dependence on high-precision numerical control equipment, higher production efficiency, better thin-wall shape and position precision of the E-shaped mirror and extremely shallow surface damage layer, and can better meet the severe requirements of the laser gyro on the processing quality of the E-shaped mirror.

Inventors

WANG CHAN
CHE CHICHENG
WANG QIANG
CHEN GUANG
LIU YANQING
GUO QINGMIAO

Assignees

武汉华中旷腾光学科技有限公司

Dates

Publication Date: 20260505
Application Date: 20231109

Claims (9)

1. A thin-wall finish machining method after slotting an E-shaped mirror is used for removing and polishing a thin-wall damaged layer after slotting the E-shaped mirror, and is characterized by comprising the following steps of: S1, designing and processing a special fixture for chemical etching of an E-shaped mirror, wherein a plurality of elliptic hollows with the same size are arranged in the fixture; S2, placing the grooved E-shaped mirrors at oval hollowed-out positions in the clamp one by one, immersing the clamp in the prepared etching liquid, and controlling the etching removal amount by adjusting the time and the temperature; step S3, after etching, respectively testing the roughness of the thin wall of the double-sided ring groove of the E-type mirror and the parallel difference between the thin wall and the polishing reference surface, and calculating the sum of the roughness and the parallel difference as the polishing removal amount; s4, preparing a special asphalt grinding head for polishing, immersing the grinding head with wool at the front end into the polishing asphalt, standing and cooling after the grinding head fully absorbs the polishing asphalt, and processing a liquid storage tank on the end face of the grinding head; s5, installing an E-shaped mirror and a grinding head to be polished on polishing equipment, aligning the grinding head with an annular groove of the E-shaped mirror, dripping polishing liquid, setting the autorotation speed of the E-shaped mirror and the autorotation speed of the grinding head, controlling the grinding head to contact with the annular groove thin wall, according to the pressure between the grinding head and the annular groove thin wall and the polishing removal rate under the processing parameters, combining the calculated polishing removal amount, adjusting the polishing duration, taking out the polished E-shaped mirror for cleaning and blow-drying; The method of the step S5 specifically comprises the following steps: Step S51, installing an E-shaped mirror to be polished and a grinding head on polishing equipment, and placing the E-shaped mirror in a lying way; step S52, tool setting is carried out, the position of a grinding head is confirmed, the grinding head is aligned with the ring groove of the E-shaped mirror, and burrs on the end face and the outer circle of the grinding head are removed by utilizing a diamond turning tool of polishing equipment; Step S53, dropwise adding polishing solution until the ring groove is full; Step S54, setting the rotation speed of the E-shaped mirror to be 10-30 r/min and the rotation speed of the grinding head to be 60-200 r/min, setting the transverse displacement amplitude of the grinding head to be capable of polishing the whole thin wall range of the annular groove according to the diameter of the grinding head and the radial dimension of the annular groove, and controlling the displacement rate to be 0.1-0.3 mm/min; step S55, controlling the grinding head to move downwards to contact with the thin wall of the annular groove, and continuously moving downwards slowly until the pressure is 1-2 bar; step S56, according to the polishing removal rate under the pressure and the processing parameters and the calculated polishing removal amount, adjusting the polishing duration to 10-30 min until the thin-wall polishing is completed; S57, taking out the E-shaped mirror, cleaning, replacing the annular groove on the other surface, and repeating the steps S51-S56; and S58, cleaning and drying, and checking the polishing effect of the E-shaped mirror thin wall.
2. The method for finishing the thin wall after grooving the E-shaped mirror according to claim 1, wherein the special clamp for chemical etching of the E-shaped mirror in the step S1 comprises a part disc and a handle, a plurality of elliptic hollows with the same size are formed on the part disc, and the elliptic hollows are used for vertically placing the E-shaped mirror in the part disc in a suspending manner in the etching process, and only the outer chamfer of the E-shaped mirror is in contact with the clamp.
3. The method for finishing the thin wall after grooving the E-shaped mirror according to claim 2, wherein the special clamp for chemical etching of the E-shaped mirror in the step S1 is made of fluoroplastic, the clamp is round, and the handle is arranged at the center of a circle.
4. The method for finishing a thin wall after grooving an E-mirror according to claim 1, wherein the method of step S2 specifically comprises: Placing grooved E-shaped mirrors in elliptical hollowed parts of a clamp one by one in batches, immersing the E-shaped mirrors in prepared etching liquid, controlling etching removal amount by adjusting time and temperature, enabling the etching removal amount to exceed the depth of a grooved damaged layer, flushing and rinsing the etched E-shaped mirrors with deionized water for 3-5 times, and drying or baking.
5. The method for finishing the thin wall after grooving the E-type mirror according to claim 1, wherein the special asphalt grinding head for polishing in the step S4 comprises a grinding head matrix, a grinding head wool part and a liquid storage tank, wherein the grinding head matrix is columnar, the bottom of the grinding head matrix is provided with the grinding head wool part, the grinding head wool part absorbs polishing asphalt and is cooled, the liquid storage tank is arranged on the end face of the bottom, and the liquid storage tank is a cross V-shaped tank.
6. The method for finishing a thin wall after grooving an E-mirror according to claim 5, wherein the method of step S4 specifically comprises: step S41, heating the prepared polishing asphalt to 200-300 ℃, and uniformly stirring, wherein the polishing asphalt is in a molten state, and smoke volatilizes on the liquid surface; Step S42, vertically immersing a grinding head wool part of the special asphalt grinding head for polishing into the molten polishing asphalt for 30-60S; step S43, lifting the grinding head from the molten polishing asphalt, hovering at a position 10-30 mm above the liquid level of the polishing asphalt for 5-10S until the wool part of the grinding head fully absorbs polishing asphalt liquid drops adsorbed on the surface, placing the grinding head on a stainless steel or glass flat plate with the end face facing downwards, standing and cooling; and S44, processing the liquid storage tank on the end face of the grinding head in a manual or numerical control mode for standby.
7. The method for finishing the thin wall after grooving the E-shaped mirror according to claim 6, wherein the polishing asphalt comprises the following components in parts by weight.
8. The method for finishing a thin wall after grooving an E-mirror according to claim 6, wherein said method in step S42 further comprises: The diameter of the grinding head is 2/3-1 times of the radial size of the single-side ring groove, and the height of the wool part of the grinding head is greater than the depth of the ring groove on any side.
9. The method for finishing the thin wall after grooving the E-shaped mirror according to claim 1, wherein the polishing solution is prepared by mixing common cerium oxide polishing powder with water.

Description

Thin-wall finish machining method for E-shaped mirror after grooving Technical Field The invention relates to the technical field of laser gyro optical part machining, in particular to a thin-wall finish machining method after slotting an E-shaped mirror. Background The laser gyro resonant cavity is essentially a ring laser, and mainly comprises a cavity, four reflectors and a cathode and an anode to form a closed ring cavity. The E-shaped mirror is one of the reflectors, is generally made of low-expansion hard and brittle materials such as quartz glass or microcrystalline glass, has an E-shaped appearance (shown in figure 1), has a double-sided ring groove and a thin-wall structure, and is plated with a high-precision reflecting film on a working surface (also called a front surface). In the working process of the resonant cavity, the E-shaped mirror middle post is required to continuously perform micro-displacement so as to compensate the change of the cavity length of the resonant cavity under different environments and always maintain the cavity length stability, so that very high requirements are put on the strength of the thin wall, secondly, in order to improve the long-term service reliability of the laser gyro, the resonant cavity is required to have extremely low leakage rate, the E-shaped mirror thin wall is often a weak point with seepage and leakage, so that the processing stage is required to reduce microcracks of the thin wall as much as possible and eliminate the hidden danger of leakage, and in addition, the installation and adjustment process of the resonant cavity is required to observe the cleanliness and the photoresist effect in the cavity and also to polish the thin wall. At present, the E-type mirror processing route is generally that a hard diamond grinding head is grooved (rough machining) -a soft polyurethane/wool grinding head is used for numerical control or manual polishing (finish machining) -a working surface is subjected to ultra-smooth polishing-film plating. The E-type mirror is made of hard and brittle glass material, and a deeper damaged layer is necessarily present after slotting. Although manual polishing removes the damaged layer well, it is difficult to control the accuracy and has extremely low efficiency. Compared with manual polishing, the numerical control polishing processing efficiency of the soft grinding head is obviously improved, but the numerical control polishing processing efficiency is also the grinding processing, so that an obvious subsurface defect layer exists on the surface after polishing, the surface regular grinding lines are unfavorable for improving the thin wall strength and eliminating the hidden danger of air leakage, in addition, the damage layer after slotting is deeper, the polishing removal amount is generally required to be larger, the soft grinding head is extremely easy to deform (the polyurethane grinding head is relatively harder and has small deformation, but the unavoidable polishing effect is poorer, the residual damage layer is deeper), and the shape and position precision of the polished thin wall flatness and the like can be obviously deteriorated. Disclosure of Invention The invention aims to solve the technical problem of providing a thin-wall finish machining method for an E-shaped mirror after slotting, which is used for removing and polishing a thin-wall damaged layer after slotting the E-shaped mirror. The method has less dependence on high-precision numerical control equipment, higher production efficiency, better E-type mirror thin-wall shape and position precision and extremely shallow surface damage layer, and can better meet the severe requirements of the laser gyro on the processing quality of the E-type mirror. The technical scheme adopted for solving the technical problems is as follows: the invention provides a thin-wall finish machining method for an E-shaped mirror after slotting, which is used for removing and polishing a thin-wall damaged layer of the E-shaped mirror after slotting, and comprises the following steps: S1, designing and processing a special fixture for chemical etching of an E-shaped mirror, wherein a plurality of elliptic hollows with the same size are arranged in the fixture; S2, placing the grooved E-shaped mirrors at oval hollowed-out positions in the clamp one by one, immersing the clamp in the prepared etching liquid, and controlling the etching removal amount by adjusting the time and the temperature; step S3, after etching, respectively testing the roughness of the thin wall of the double-sided ring groove of the E-type mirror and the parallel difference between the thin wall and the polishing reference surface, and calculating the sum of the roughness and the parallel difference as the polishing removal amount; s4, preparing a special asphalt grinding head for polishing, immersing the grinding head with wool at the front end into the polishing asphalt, standing and cooling after the