Quartz inertial component efficient machining method based on ultrafast laser

Abstract

The invention discloses an efficient machining method for a quartz inertial component based on ultrafast laser. The efficient machining method comprises the steps that a special Bessel cutting head is built according to the thickness of a quartz base material; building an ultrafast laser processing platform; parameters of a laser and a displacement table are adjusted according to Bessel cutting head correlation; planning a laser scanning path of the quartz component, and setting a guide line; the quartz base material is heated after being cleaned, so that the laser absorptivity of quartz is improved; after the quartz base material is positioned, the displacement table is linked with the laser to modify and form the quartz base material; carrying out ultrasonic cleaning on the modified quartz base material by using an HF solution so as to separate the quartz component; and polishing the surface of the quartz component by using a grinding and polishing machine to obtain the high-surface-quality quartz component. The method can adapt to cutting of the quartz base material with the thickness of 50-500 microns, the laser utilization rate is high, the energy loss is small, the forming efficiency is high, and no thermal stress exists in the splitting process. And the processed and molded quartz member has the characteristics of good consistency, high dimensional precision, excellent surface quality and the like.

Description

Technical Field

[0001] The invention belongs to the field of precision laser manufacturing and relates to a high-efficiency processing method of a quartz inertial component based on ultrafast laser. Background Art

[0002] Key components of inertial devices such as quartz vibration beams and pendulums are cut from quartz substrates. The dimensional accuracy and surface quality of quartz components have a decisive influence on the performance of the final assembled inertial instrument. Improving the processing technology of quartz components and improving the processing quality can effectively improve the performance of quartz inertial devices.

[0003] The traditional quartz processing method is mechanical grinding wheel cutting, which has many problems such as large cutting line width, serious edge collapse, large amount of material removal, powder, and processing stress concentration, which restrict the improvement of processing effect. At the same time, conventional laser processing methods are prone to problems such as excessive energy concentration reducing efficiency or too low energy to reach the damage threshold. The ultrafast laser filament cutting process based on Bessel light has many advantages such as small cutting seam width, high precision, high efficiency, invisible cutting without dust, low thermal stress, and non-contact. It can solve the disadvantages of grinding wheel cutting and improve the processing effect of quartz materials. It is the future development direction of quartz-based high-precision inertial component processing. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose an efficient processing method for quartz inertial components based on ultrafast laser to solve the problems of large cutting line width of the grinding wheel, serious edge collapse, powder presence, processing stress concentration, etc., as well as the problem that the conventional laser cutting method has energy loss and reduces efficiency, or the energy is too low to reach the damage threshold.

[0005] The technical solution of the present invention is: a high-efficiency processing method of quartz inertial components based on ultrafast laser, comprising:

[0006] Build the Bessel cutting head according to the thickness of the quartz substrate;

[0007] Building a laser processing platform for cutting the contour of a quartz component on a quartz substrate;

[0008] Adjust the laser and translation stage parameters according to the constructed Bessel cutting head;

[0009] Plan the laser scanning path of quartz components;

[0010] After cleaning the quartz substrate, temperature control is performed;

[0011] After the quartz substrate is positioned, laser modification and shaping is performed according to the scanning path to obtain the contour of the modified quartz component;

[0012] HF solution is configured to ultrasonically clean the quartz substrate, so that the processed quartz component is separated from the quartz substrate;

[0013] The quartz components are surface polished to reduce the surface roughness caused by the HF solution. After polishing, they are rinsed with clean water and dried with a hair dryer to complete the processing.

[0014] The temperature control treatment is performed on the quartz substrate after cleaning, including: placing the quartz substrate on a hot plate, heating for 3 to 5 minutes until the temperature is uniform, and controlling the temperature at 90°C ± 10°C; the hot plate is made of ceramic material.

[0015] The Bessel cutting head is built according to the thickness of the quartz substrate, including: the Bessel cutting head is composed of a conical lens and a beam reduction 4f system; the focal depth of the Bessel beam is adjusted by selecting different conical lenses and beam reduction 4f systems to achieve control of the hole depth and aperture.

[0016] Axis lens target base angle 4f system beam reduction ratio Where n a is the refractive index of the conic lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, W1 is the incident beam diameter, W2 is the beam diameter after focusing, and l is the focal depth of the beam after focusing.

[0017] The parameters of the laser and the displacement stage are adjusted, including: laser power P = 0.5w ~ 10w, single pulse energy Repetition rate The filament length l0=100 μm, the single pulse energy E0=50 μJ, and the movement speed of the translation stage v=f×0.001.

[0018] When planning the laser scanning path of quartz components, guide lines are set at complex locations with a line spacing of 200μm, cross lines are filled, and R0.1mm chamfers are set at right-angle transition positions to prevent stress concentration cracks.

[0019] When HF solution is configured to perform ultrasonic cleaning on the quartz substrate, the ultrasonic frequency is 40kHz to 50kHz, the HF concentration is 8% to 12%, and the HF solution is replaced every 30 minutes.

[0020] The preparation steps of HF solution are as follows: take 25 ml of 40% HF acid solution and pour it into a 100 ml beaker; use a measuring cylinder and a dropper to measure 75 ml of distilled water and inject it into the 100 ml beaker, and stir and mix evenly.

[0021] The quartz component is surface polished by a grinding and polishing machine, the rotation speed of the grinding and polishing machine is 10 to 50 rpm, and the flatness after polishing is ≤1 μm.

[0022] The advantages of the present invention compared with the prior art are:

[0023] 1. The present invention improves the laser absorption rate of quartz during processing, reduces residual stress, and improves processing quality by controlling the temperature of the processed quartz substrate;

[0024] 2. The present invention builds a special Bessel processing head and customizes the process parameters according to the thickness of the quartz substrate to be processed, so as to achieve efficient and high-precision processing of quartz materials;

[0025] 3. The present invention specially plans the laser scanning path, sets guide lines, and slightly chamfers the right-angle edges to prevent edge cracks caused by stress concentration;

[0026] 4. The present invention uses HF solution ultrasonic technology to ultrasonically clean the quartz components after laser processing to separate the parts from the substrate;

[0027] 5. The present invention uses a grinding and polishing process to polish the quartz component after HF corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of a highly efficient processing method of a quartz inertial component based on ultrafast laser.

[0029] Figure 2 Schematic diagram of the Bessel optical path in the present invention.

[0030] Figure 3 It is a schematic diagram of an ultrafast laser processing platform for efficient quartz cutting of the present invention. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention will be further described below with reference to the accompanying drawings:

[0032] like Figure 1 As shown, the processing scheme of the present invention is as follows:

[0033] The first step is to build a Bessel cutting head according to the thickness of the quartz substrate, which is used to focus the Gaussian beam emitted by the laser into a Bessel beam.

[0034] The quartz substrate is the raw material to be processed and formed, and is a rectangular or square thin plate structure with a thickness of 50 to 500 μm. After the quartz substrate is processed, the quartz components are formed, and the quartz components include quartz vibration beams, quartz pendulums, etc.

[0035] The specific construction method of the Bessel light cutting head described in the first step is that the Bessel cutting head is composed of a conic lens and a beam reduction 4f system; a weakly focused Bessel beam is first generated using an axicon with a small bottom angle, and then a tightly focused Bessel beam with a small spot is generated through the beam reduction 4f system. By selecting different conic lenses and beam reduction 4f systems to adjust the focal depth of the Bessel beam, the hole depth and aperture can be controlled to meet the requirements of quartz processing.

[0036] Among them, the 4f system adopts a Kepler structure, which is composed of two confocal convex lenses, which can realize the generation of a real Bessel interference zone behind the system. The relationship and function of the lenses: The Gaussian beam is incident on the axicon of the axon lens, and after transmission, the beam overlaps and interferes to generate the first Bessel zone. The midpoint of the first Bessel zone is used as the reference position ( Figure 2 As shown in the figure, the front focal plane of the first lens of the 4f system coincides with it, so that the central light of the annular beam passing through the first lens will propagate horizontally. After passing through the beam reduction 4f system, the beam will converge again to form the second Bessel area. After being reduced by the 4f system (f1>f2), the semi-cone angle of the Bessel beam will increase; the spot diameter will decrease, and the focal depth of the second Bessel area will also be shortened.

[0037] To achieve single-shot laser processing, the focal depth l is the same as the thickness of the quartz substrate. The target bottom angle a of the axon and the 4f system beam reduction ratio are obtained by numerical calculation. Select the corresponding lens based on this, and the calculation formula is as follows.

[0038]

[0039]

[0040] Among them, n a is the material refractive index of the axon, a is the bottom angle of the axon, f1 is the focal length of the first lens, f2 is the focal length of the second lens, W1 is the diameter of the incident Gaussian beam, W2 is the diameter of the Bessel beam after focusing, and l is the focal depth of the Bessel beam after focusing.

[0041] The second step is to build an ultrafast laser processing platform for ultrafast laser filament cutting of quartz components, cutting the quartz substrate into quartz components of specific sizes and shapes.

[0042] like Figure 3 As shown, the ultrafast laser processing platform needs to include: ultrafast laser 1, front beam expander 2, reflector 3, Bessel cutting head 4, xy axis translation stage 5, z axis translation stage 6, rangefinder 7, CCD camera 8, hot plate 9;

[0043] Among them, the ultrafast laser is used to emit the laser beam. The spatial distribution of the laser beam obeys the Gaussian distribution. The wavelength of the emitted laser is 515nm±10nm, and the beam quality is M 2 ≤1.5, pulse width ≤500fs;

[0044] The front beam expander is used to adjust the spot diameter of the Bessel cutting head. After the laser beam is collimated and expanded, a collimated beam with a spot diameter of 5mm±1mm is formed;

[0045] Among them, the Bessel cutting head is used to transform the collimated beam into a Bessel beam that can be used for processing;

[0046] Among them, the z-axis translation stage is equipped with a Bessel cutting head, a rangefinder, and a CCD camera through a structural component to adjust the focal length; the xy-axis translation stage is located directly below the Bessel cutting head and is used to drive the quartz substrate to move along the planned path; the rangefinder is used to measure the distance between the Bessel cutting head and the upper surface of the quartz substrate for focal length adjustment; the CCD camera is used for visual positioning of the quartz substrate. The positioning accuracy of the xy-axis translation stage and the z-axis translation stage is ≤1μm to ensure processing accuracy.

[0047] The hot plate is placed on an xy-axis displacement stage to control the temperature of the quartz substrate and adjust the laser absorption rate of the quartz.

[0048] The third step is to adjust the laser and translation stage parameters according to the Bessel cutting head built in the first step.

[0049] Among them, the processing parameters of femtosecond laser are: power P0.5w~10w, single pulse energy E, and repetition rate f are calculated according to the wire length l of the built Bessel cutting head. Single pulse energy Repetition rate When the filament length l0=100μm, the single pulse energy E0=50μJ.

[0050] The start and stop of the xy-axis translation stage must be coordinated with the laser. The laser emits light 50ms after the xy-axis translation stage moves, and stops 50ms before the xy-axis translation stage stops, skipping the acceleration and deceleration time of the translation stage. The translation stage movement speed v = f × 0.001 (mm / s).

[0051] The fourth step is to plan the laser scanning path for quartz components. The planned scanning path is used to control the movement trajectory of the xy-axis translation stage.

[0052] The specific path is the outline of the quartz component cutting pattern and the guide line drawn. The guide line is set at a complex position, the line spacing is 200μm, the cross line is filled, and the right-angle transition position of the pattern is set with R0.1mm chamfer to prevent stress concentration and cracks.

[0053] The fifth step is to heat the quartz substrate after cleaning, control the temperature at 90°C ± 10°C, and evenly distribute the temperature to improve the absorption rate of quartz to laser.

[0054] Among them, the temperature control method for quartz is to place the quartz substrate on the hot plate and heat it for 3 to 5 minutes until the temperature is uniform. The hot plate is made of ceramic, with a maximum temperature of ≥100°C and a temperature control accuracy of 1°C.

[0055] The quartz substrate cleaning method is to use an alcohol solution ultrasonic treatment, wherein the alcohol concentration is 60% to 70% and the ultrasonic frequency is 40kHz to 50kHz. After cleaning, the surface of the quartz substrate is blown dry.

[0056] The sixth step is to laser modify and shape the quartz substrate after positioning. The quartz substrate and the hot plate are placed on the plane of the xy-axis translation stage, and the xy-axis coordinates are positioned and the z-axis focal length is adjusted. The laser emits light according to the set parameters, and the translation stage moves at a constant speed along the planned path to obtain the contour of the modified quartz component on the quartz substrate.

[0057] The xy axis coordinate positioning method is to move the xy axis translation stage to move the quartz substrate to the center of the CCD camera field of view, calculate the xy coordinate during cutting through the relative position of the CCD camera and the Bessel cutting head, and move the quartz substrate to this coordinate.

[0058] The z-axis coordinate positioning method is as follows: the distance between the Bessel cutting head and the quartz substrate is measured by a rangefinder, and the Bessel cutting head is moved by a z-axis translation stage so that the distance between the lower end of the cutting head and the upper surface of the quartz substrate is Where f2 is the focal length of the cutting head and H is the thickness of the quartz.

[0059] In the seventh step, a mixed solution of HF and distilled water is prepared as a corrosive solution, and the quartz substrate is ultrasonically cleaned using the corrosive solution to separate the quartz component from the quartz substrate.

[0060] The ultrasonic frequency is 40kHz to 50kHz, the HF concentration is 8% to 12%, and the steps for preparing the etching solution are as follows: (1) Take 25ml of 40% HF acid solution and pour it into a 100ml beaker. (2) Use a measuring cylinder and a dropper to measure 75ml of distilled water and inject it into the 100ml beaker in the previous step.

[0061] Observe every 15 minutes and replace the HF solution every 30 minutes until the processed quartz component is separated from the substrate.

[0062] Step 8: Use a grinding and polishing machine to polish the surface of the quartz component to reduce the problem of increased surface roughness of the quartz component caused by the corrosive liquid. The speed of the grinding and polishing machine is 10-50rpm, and the flatness after polishing is ≤1μm. After polishing, take out the quartz component, rinse it with clean water to ensure that the surface is not contaminated, and blow it dry with a hair dryer.

[0063] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. An efficient processing method for quartz inertial components based on ultrafast laser, characterized in that: include: Build the Bessel cutting head according to the thickness of the quartz substrate; Building a laser processing platform for cutting the contour of a quartz component on a quartz substrate; Adjust the laser and translation stage parameters according to the constructed Bessel cutting head; Plan the laser scanning path of quartz components; After cleaning the quartz substrate, temperature control is performed; After the quartz substrate is positioned, laser modification and shaping is performed according to the scanning path to obtain the contour of the modified quartz component; HF solution is configured to ultrasonically clean the quartz substrate, so that the processed quartz component is separated from the quartz substrate; The quartz components are surface polished to reduce the surface roughness caused by the HF solution. After polishing, they are rinsed with clean water and dried with a hair dryer to complete the processing.

2. According to claim 1, a highly efficient processing method for quartz inertial components based on ultrafast laser is characterized in that: The temperature control treatment is performed on the quartz substrate after cleaning, including: placing the quartz substrate on a hot plate, heating for 3 to 5 minutes until the temperature is uniform, and controlling the temperature at 90°C ± 10°C; the hot plate is made of ceramic material.

3. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 1, characterized in that: The Bessel cutting head is built according to the thickness of the quartz substrate, including: the Bessel cutting head is composed of a conical lens and a beam reduction 4f system; the focal depth of the Bessel beam is adjusted by selecting different conical lenses and beam reduction 4f systems to achieve control of the hole depth and aperture.

4. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 3, characterized in that: Axis lens target base angle 4f system beam reduction ratio where n a is the refractive index of the conic lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, W1 is the incident beam diameter, W2 is the beam diameter after focusing, and l is the focal depth of the beam after focusing.

5. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 1, characterized in that: The parameters of the laser and the displacement stage are adjusted, including: laser power P = 0.5w ~ 10w, single pulse energy Repetition rate The filament length l0=100 μm, the single pulse energy E0=50 μJ, and the movement speed of the translation stage v=f×0.

001.

6. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 1, characterized in that: When planning the laser scanning path of quartz components, guide lines are set at complex locations with a line spacing of 200μm, cross lines are filled, and R0.1mm chamfers are set at right-angle transition positions to prevent stress concentration cracks.

7. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 1, characterized in that: When HF solution is configured to perform ultrasonic cleaning on the quartz substrate, the ultrasonic frequency is 40kHz to 50kHz, the HF concentration is 8% to 12%, and the HF solution is replaced every 30 minutes.

8. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 1, characterized in that: The preparation steps of HF solution are as follows: take 25 ml of 40% HF acid solution and pour it into a 100 ml beaker; use a measuring cylinder and a dropper to measure 75 ml of distilled water and inject it into the 100 ml beaker, and stir and mix evenly.

9. The method for efficiently processing quartz inertial components based on ultrafast laser according to claim 1, characterized in that: The quartz component is surface polished by a grinding and polishing machine, the rotation speed of the grinding and polishing machine is 10 to 50 rpm, and the flatness after polishing is ≤1 μm.

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