A length measuring device based on laser interference

Abstract

The application relates to the technical field of length measurement, and particularly discloses a length measurement device based on laser interference, which comprises a laser measurement module, an air curtain channel module, an air curtain construction module and a channel adjusting module; the laser measurement module is used for emitting and receiving laser, and the optical path difference change is measured by using the interference principle; the length measurement device can accurately measure the trace length change of a workpiece in real time and continuously while the workpiece is machined by a machining module; the air curtain channel module is used for forming a straight channel between a laser head and a measurement mirror; the air curtain construction module is used for continuously introducing inert gas into the channel to form a laminar stable air curtain atmosphere, so that the oil mist, dust, cutting fluid splashing, hot air turbulence and other pollutants and interference factors generated in a machining area are effectively blocked, the pollutants and interference factors are prevented from entering a laser path, and the measurement beam is prevented from being disturbed by environmental factors during propagation.

Description

Technical Field

[0001] This invention relates to the field of length measurement technology, and more specifically, to a length measurement device based on laser interferometry. Background Technology

[0002] In the field of precision machining, laser interferometry is widely used for real-time deformation monitoring during workpiece processing due to its nanometer-level precision. However, in actual machining environments, laser interferometry faces the problem of machining contaminants interfering with the optical path. Spilled cutting fluid, metal dust, oil mist, and other contaminants can directly intrude into the laser propagation path, causing beam scattering, attenuation, or abrupt changes in refractive index, resulting in measurement signal distortion or even interruption. In addition, air turbulence and thermal disturbance are also adverse factors affecting laser interferometry. Severe temperature gradients in the machining area (such as tool friction heat and coolant temperature difference) cause changes in air density, generating random thermal turbulence. At the same time, equipment movement causes airflow disturbance. These factors significantly change the air refractive index, introducing uncontrollable optical path errors and severely reducing the accuracy of laser interferometry. Summary of the Invention

[0003] To overcome the above-mentioned technical problems, this invention proposes a length measurement device based on laser interferometry.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A length measuring device based on laser interferometry is applied to a machining unit, the machining unit including a tooling module for clamping workpieces and a machining module for machining the workpieces; the length measuring device includes:

[0006] A laser measurement module includes a mounting plate disposed on a processing module and a measuring reflector attached to a workpiece. A laser head adapted to the measuring reflector is mounted on the mounting plate, and a reference measuring mirror is built into the laser head.

[0007] A sealing sleeve, which is located outside the laser head;

[0008] An air curtain channel module, which is mounted on a sealing sleeve, is used to form an air curtain channel between the laser head and the measuring mirror;

[0009] An air curtain construction module, which is mounted on a sealing sleeve, is used to create an air curtain atmosphere within the air curtain channel.

[0010] The channel adjustment module is located outside the air curtain channel module and is used to adjust the length of the air curtain channel.

[0011] As a further embodiment of the present invention: the air curtain channel module includes a corrugated pipe installed on the lower end face of the sealing sleeve and an elastic air curtain diaphragm coaxially distributed inside the corrugated pipe. The upper end of the elastic air curtain diaphragm is telescopically disposed inside the sealing sleeve, and the lower end of the elastic air curtain diaphragm is fixedly connected to the lower end of the corrugated pipe.

[0012] As a further aspect of the present invention: an annular groove is provided inside the sealing sleeve, a slip ring is slidably embedded in the annular groove, and a plurality of traction springs connected to the slip ring are arranged circumferentially inside the annular groove.

[0013] As a further aspect of the present invention: a conical cover is provided at the lower end of the corrugated pipe, and a flow guide is provided on the inner side of the conical cover.

[0014] As a further aspect of the present invention: the air curtain construction module includes an air cavity opened within a sealing sleeve, the inner side of the air cavity is provided with a plurality of air jets communicating with the air curtain channel, and the outer side of the air cavity is connected to an air pipe.

[0015] As a further embodiment of the present invention: the channel adjustment module includes a mounting sleeve disposed on the mounting plate and a bearing seat disposed on the conical cover, a threaded rod is rotatably mounted inside the bearing seat, the threaded rod is threaded through the mounting sleeve, and a crank handle is provided at the upper end of the threaded rod.

[0016] As a further aspect of the present invention, it also includes an anti-condensation module, which includes a drive motor fixed to a mounting plate and a toothed ring rotatably embedded in a sealing sleeve. The output end of the drive motor is equipped with a gear that meshes with the toothed ring, and the lower end of the toothed ring is fixed with a scraper through a connecting frame. The scraper is in contact with the inner wall of the elastic air curtain diaphragm.

[0017] As a further aspect of the present invention: an annular drainage plate adapted to the elastic air curtain diaphragm is provided on the inner side of the conical cover, and a drainage groove is formed between the annular drainage plate and the elastic air curtain diaphragm. A drainage channel communicating with the bottom of the drainage groove is opened inside the conical cover.

[0018] As a further aspect of the present invention: the tooling module includes a magnetic suction plate for magnetically fixing the lower end face of the workpiece, and the magnetic suction plate is provided with an inner support assembly for radially expanding and fixing the inner wall of the workpiece.

[0019] As a further aspect of the present invention: the inner support assembly includes a clamping cylinder installed in the magnetic suction plate and several sets of inner support plates circumferentially distributed around the clamping cylinder. A lifting platform is installed at the output end of the clamping cylinder, and a connecting rod is hinged between the lifting platform and each inner support plate.

[0020] The beneficial effects of this invention are:

[0021] This invention uses a laser measurement module to emit and receive lasers, and utilizes the principle of interference to measure changes in optical path difference. This allows for real-time, continuous, and precise measurement of minute length changes in a workpiece while the processing module is performing machining operations on the workpiece.

[0022] A straight channel is formed between the laser head and the measuring mirror by an air curtain channel module. Inert gas is continuously introduced into the channel by the air curtain construction module to form a laminar and stable air curtain atmosphere. This effectively blocks pollutants and interference factors such as oil mist, dust, cutting fluid splashes, and hot air turbulence generated in the processing area, preventing them from entering the laser path and ensuring that the measuring beam is not affected by environmental factors during propagation. Attached Figure Description

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the structure of the invention and the machining unit;

[0025] Figure 2 This is a structural schematic diagram of the invention and the machining unit from another perspective;

[0026] Figure 3 This is a schematic diagram of the structure of the present invention;

[0027] Figure 4 This is a partial structural diagram of the present invention;

[0028] Figure 5 This is a schematic diagram of the internal structure of the air curtain channel module in this invention;

[0029] Figure 6 for Figure 5 Enlarged view of point A in the middle;

[0030] Figure 7 for Figure 5 Enlarged view at point B in the middle;

[0031] Figure 8 This is a schematic diagram of the machining unit.

[0032] Figure 9 This is a structural schematic diagram of the tooling module;

[0033] Figure 10 for Figure 9 Enlarged view of point C in the middle.

[0034] In the picture:

[0035] 100. Laser measurement module; 110. Mounting plate; 120. Laser head; 130. Measurement reflector;

[0036] 200. Sealing sleeve;

[0037] 300. Air curtain channel module; 310. Bellows; 320. Conical cover; 330. Elastic air curtain diaphragm; 340. Annular groove; 350. Slip ring; 360. Traction spring; 370. Annular guide plate; 380. Drainage channel; 390. Flow guide cover;

[0038] 400. Air curtain construction module; 410. Air cavity; 420. Air jet nozzle; 430. Air pipe;

[0039] 500. Channel adjustment module; 510. Bearing housing; 520. Threaded rod; 530. Mounting sleeve; 540. Handle;

[0040] 600. Anti-condensation module; 610. Drive motor; 620. Gear; 630. Gear ring; 640. Connecting frame; 650. Scraper blade;

[0041] 700. Tooling module; 710. Magnetic suction plate; 720. Internal support assembly; 721. Clamping cylinder; 722. Lifting platform; 723. Internal support plate; 724. Connecting rod;

[0042] 800. Machining module; 810. Transverse component; 811. Transverse guide rod; 812. Transverse slider; 813. Transverse motor; 814. Transverse lead screw; 820. Longitudinal component; 821. Longitudinal guide rod; 822. Longitudinal slider; 823. Longitudinal motor; 824. Longitudinal lead screw; 830. Lifting component; 831. Lifting guide rod; 832. Lifting slider; 833. Lifting motor; 834. Lifting lead screw; 840. Machining component; 841. Machining motor; 842. Milling disc;

[0043] 900. Workpiece. Detailed Implementation

[0044] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0045] Please see Figure 1 and Figure 2 The present invention discloses a length measuring device based on laser interferometry, which is applied to a machining unit. The machining unit includes a tooling module 700 for clamping a workpiece 900 and a machining module 800 for machining the workpiece 900.

[0046] Please see Figure 3 and Figure 4 The length measuring device includes a laser measuring module 100, a sealing sleeve 200, an air curtain channel module 300, an air curtain construction module 400, and a channel adjustment module 500. The laser measuring module 100 includes a mounting plate 110 mounted on a processing module 800 and a measuring reflector 130 attached to a workpiece 900. A laser head 120 adapted to the measuring reflector 130 is mounted on the mounting plate 110, and the laser head 120 has a built-in reference measuring mirror (not shown in the figure). The sealing sleeve 200 is fitted outside the laser head 120. The air curtain channel module 300 is mounted on the sealing sleeve 200 and forms an air curtain channel between the laser head 120 and the measuring reflector 130. The air curtain construction module 400 is mounted on the sealing sleeve 200 and constructs an air curtain atmosphere within the air curtain channel. The channel adjustment module 500 is located outside the air curtain channel module 300 and adjusts the length of the air curtain channel.

[0047] Specifically, the workpiece 900 is clamped and fixed by the tooling module 700, the measuring reflector 130 is attached to the upper surface of the workpiece 900, the air curtain channel module 300 is adjusted by the channel adjustment module 500 so that the lower end of the air curtain channel module 300 covers the periphery of the measuring reflector 130, forming a straight air curtain channel connecting the laser head 120 and the measuring reflector 130, and then the inert gas such as nitrogen is continuously introduced into the air curtain channel by the air curtain construction module 400 to form a laminar flow stable air curtain atmosphere to prevent interference with the laser path;

[0048] When the processing module 800 performs machining operations on the workpiece 900, the laser emitted by the laser head 120 of the air curtain construction module 400 is split into a reference beam and a measurement beam by an internal beam splitter. The reference beam is directed perpendicularly to a fixed reference mirror and reflected back to the beam splitter, while the measurement beam is directed perpendicularly to a measurement mirror 130 fixed on the workpiece 900 through a stable air curtain atmosphere in the air curtain channel and reflected back to the beam splitter. The two reflected beams meet again at the beam splitter and interfere. By calculating the change in the optical path difference between the two coherent beams, the minute length change of the workpiece 900 during the machining process can be accurately measured.

[0049] It should be noted that the present invention uses the laser measurement module 100 to emit and receive lasers and uses the interference principle to measure the change in optical path difference. This allows for real-time and continuous precise measurement of minute length changes of the workpiece 900 while the processing module 800 is performing machining operations on the workpiece 900.

[0050] A straight channel is formed between the laser head 120 and the measuring mirror 130 by the air curtain channel module 300, and inert gas is continuously introduced into the channel by the air curtain construction module 400 to form a laminar and stable air curtain atmosphere. This effectively blocks pollutants and interference factors such as oil mist, dust, cutting fluid splashes, and hot air turbulence generated in the processing area, preventing them from entering the laser path and ensuring that the measuring beam is not affected by environmental factors during propagation.

[0051] The stable inert gas curtain atmosphere has a more stable density and refractive index than air, which minimizes optical path error and beam drift caused by factors such as air disturbance, temperature gradient, and humidity change, providing a highly stable optical environment for laser interferometry, thus ensuring extremely high measurement accuracy and reliability.

[0052] The sealing sleeve 200 is located outside the laser head 120. Together with the air curtain channel module 300 covering the measuring reflector 130, they form a relatively closed measuring optical path space, which further enhances the protection against external pollution and disturbance.

[0053] In one embodiment, please refer to Figure 4 and Figure 5 The air curtain channel module 300 includes a bellows 310 installed on the lower end face of the sealing sleeve 200 and an elastic air curtain diaphragm 330 coaxially distributed within the bellows 310. The upper end of the elastic air curtain diaphragm 330 is telescopically disposed within the sealing sleeve 200, and the lower end of the elastic air curtain diaphragm 330 is fixedly connected to the lower end of the bellows 310.

[0054] Specifically, a straight air curtain channel is formed inside the elastic air curtain diaphragm 330. The bellows 310 wraps and protects the elastic air curtain diaphragm 330 to prevent deformation of the straight air curtain channel due to external environmental interference. The bellows 310 can be extended and retracted according to the distance between the laser head 120 and the measuring mirror 130. During the extension and retraction adjustment of the bellows 310 driven by the channel adjustment module 500, the internal elastic air curtain diaphragm 330 can adaptively deform axially to always remain taut. In this way, no matter how the length of the air curtain channel changes, the straight extension of the internal air curtain channel can be maintained, so that the gas atmosphere in each area of ​​the air curtain channel remains consistent and the accuracy of the beam propagation path is improved.

[0055] It should be noted that the elastic air curtain diaphragm 330 forms a straight air curtain channel inside. When the channel adjustment module 500 drives the bellows 310 to extend and retract to adapt to different distances, the elastic air curtain diaphragm 330 can always remain taut, ensuring that no matter how the length of the air curtain channel changes, the internal channel always maintains a straight extension, providing a straight propagation path for the light beam.

[0056] The straight-lined and stable air curtain channel allows the inert gas introduced by the air curtain construction module 400 to form a consistent gas atmosphere (density, flow rate, laminar flow characteristics) in various areas of the channel. The uniform and stable atmosphere effectively improves the accuracy and reliability of the laser measurement beam (from the laser head 120 to the measurement mirror 130 and back) propagation in the channel, and reduces optical path deviation caused by changes in channel shape or uneven airflow.

[0057] The bellows 310 are coaxially distributed outside the elastic air curtain diaphragm 330 to wrap and protect it. The rigid or semi-rigid structure of the bellows 310 can effectively resist the interference of the external environment (such as splashing cutting fluid, accidental collision or airflow impact) and prevent it from causing unexpected deformation or damage to the internal elastic air curtain diaphragm 330 and the straight air curtain channel.

[0058] When the channel adjustment module 500 drives the bellows 310 to extend and retract, the internal elastic air curtain diaphragm 330 can smoothly follow the extension and retraction, always maintaining an effective sealing cover between the lower port of the channel and the measuring reflector 130, ensuring the sealing and isolation effect of the air curtain.

[0059] Further, please refer to Figure 5 and Figure 6 For the axial expansion and contraction adjustment of the elastic air curtain diaphragm 330, an annular groove 340 is provided in the sealing sleeve 200, a slip ring 350 is slidably embedded in the annular groove 340, and a plurality of traction springs 360 connected to the slip ring 350 are arranged circumferentially in the annular groove 340.

[0060] Specifically, the elastic air curtain diaphragm 330 has a certain elastic deformation performance, and the traction spring 360 can apply tension to the slip ring 350, thereby using the slip ring 350 to pull the elastic air curtain diaphragm 330 to ensure that the elastic air curtain diaphragm 330 can always remain taut; when the bellows 310 elongates, the elastic air curtain diaphragm 330 can adapt to elongation, and the slip ring 350 can also slide downward a certain distance in the annular groove 340 to compensate for the elongation of the elastic air curtain diaphragm 330 and prevent the elastic air curtain diaphragm 330 from breaking due to exceeding its own elongation limit.

[0061] It should be noted that the traction spring 360 applies a continuous axial traction force to the elastic air curtain diaphragm 330 through the slip ring 350, which effectively overcomes the effects of gravity or deformation relaxation, ensuring that the elastic air curtain diaphragm 330 always remains taut at any length, thereby maintaining the straight extension of the internal air curtain channel and ensuring the accuracy of the beam propagation path.

[0062] When the bellows 310 is extended under the drive of the channel adjustment module 500, the elastic air curtain diaphragm 330 extends adaptively. At the same time, the slip ring 350 slides down along the annular slide groove 340 under the action of the traction spring 360. This sliding action compensates for the extra length required by the elastic air curtain diaphragm 330, preventing it from breaking or permanently deforming due to the elongation exceeding its own elastic limit, thereby improving the structural reliability and service life.

[0063] The sliding of the slip ring 350 within the annular groove 340, combined with the extension and retraction characteristics of the traction spring 360, enables the structure to dynamically adapt to changes in the length of the bellows 310. During adjustment, deformation is automatically compensated, and the tautness and integrity of the elastic air curtain diaphragm 330 can be maintained without additional control.

[0064] Furthermore, please refer to Figure 5 and Figure 7 In order to completely cover the space surrounding the measuring reflector 130 with air curtain atmosphere, a conical cover 320 is provided at the lower end of the bellows 310, and a flow guide 390 is provided on the inner side of the conical cover 320.

[0065] Specifically, the measuring mirror 130 is covered by a conical shell 320, and the airflow guide 390 guides the airflow inward, so that the airflow in the air curtain channel flows from top to bottom through the airflow guide 390. In this way, when the processing module 800 is displaced in the horizontal range, the conical shell 320 can always cover the reflection range of the measuring mirror 130, and the air curtain atmosphere always surrounds the measuring mirror 130 to maintain the temperature of the laser propagation path.

[0066] It should be noted that the conical cover 320 is located at the lower end of the bellows 310. Its conical structure can always wrap around and cover the measuring reflector 130 when the processing module 800 is horizontally displaced, ensuring that the reflection area of ​​the measuring reflector 130 is always within the air curtain protection range, and avoiding the failure of air curtain protection due to equipment movement.

[0067] The flow guide 390 is located inside the conical shell 320, which forces the inert gas flow in the air curtain channel to flow inward and downward, forming a directional laminar flow that wraps around the measuring mirror 130, so that the air curtain atmosphere tightly covers the space above and around the measuring mirror 130, effectively isolating external interference.

[0068] The directional air curtain continuously surrounds the measuring mirror 130, forming a uniform and undisturbed gas environment on the surface of the mirror. This significantly reduces thermal gradients and air turbulence, ensuring the stability of the reflection path and the consistency of the optical path of the laser beam at the measuring mirror 130.

[0069] In yet another embodiment, please refer to Figure 5 and Figure 6The air curtain construction module 400 includes an air cavity 410 opened in the sealing sleeve 200. The air cavity 410 has a plurality of air jets 420 that communicate with the air curtain channel circumferentially opened on the inner side of the air cavity 410. An air pipe 430 is connected to the outer side of the air cavity 410.

[0070] Specifically, an inert airflow is continuously introduced into the air chamber 410 through the trachea 430, and the airflow is uniformly injected into the air curtain channel through each jet nozzle 420 in a circumferential direction, thereby forming a laminar and stable air curtain atmosphere in the air curtain channel.

[0071] The air chamber 410 serves as an airflow distribution chamber. Multiple jet nozzles 420, evenly distributed around the circumference, inject inert gas into the air curtain channel. The annular array of gas supply ensures that the inert gas is injected evenly and synchronously along the entire circumference of the channel, thereby forming a uniform, symmetrical, and stable laminar air curtain atmosphere within the air curtain channel.

[0072] The uniformly injected airflow is more likely to form a stable, low-turbulence laminar flow state in the straight-extending air curtain channel, which can effectively suppress the disturbance and eddy current inside the gas, and provide a gas medium environment with highly consistent optical performance and extremely low interference for the laser measurement beam (from the laser head 120 to the measurement mirror 130 and back), minimizing beam jitter and optical path error.

[0073] The air chamber 410 is directly opened inside the sealing sleeve 200, the air nozzle 420 is located inside the air chamber 410 and is connected to the air curtain channel, and the air pipe 430 is connected to the outside of the air chamber 410. The integrated structure makes the air supply system structure more airtight, reduces the risk of leakage, and ensures the directness and efficiency of the air supply path.

[0074] Further, please refer to Figure 4 The channel adjustment module 500 includes a mounting sleeve 530 disposed on the mounting plate 110 and a bearing seat 510 disposed on the conical cover 320. A threaded rod 520 is rotatably mounted inside the bearing seat 510. The threaded rod 520 is threaded through the mounting sleeve 530, and a crank handle 540 is disposed at the upper end of the threaded rod 520.

[0075] Specifically, by cranking the handle 540 to drive the threaded rod 520 to rotate circumferentially relative to the bearing seat 510, the threaded rod 520 can rotate within the mounting sleeve 530, thereby driving the lower conical cover 320 to move up and down, so as to flexibly adjust the contraction state of the bellows 310 according to the distance between the laser head 120 and the measuring reflector 130.

[0076] The screw rod 520 is driven to rotate circumferentially within the bearing housing 510 by the crank handle 540. The screw rod 520 and the mounting sleeve 530 are threaded together to convert the rotational motion into precise linear displacement. The lifting and lowering of the conical cover 320 and the bellows 310 can be flexibly controlled, thereby precisely adjusting the extension and retraction length of the air curtain channel according to the actual distance between the laser head 120 and the measuring reflector 130.

[0077] The threaded rod 520 is stably supported on the conical cover 320 by the bearing seat 510, and the mounting sleeve 530 is fixed to the mounting plate 110, forming a rigid transmission and support structure. The threaded transmission itself has a self-locking characteristic, which can automatically maintain the position after adjustment, preventing the air curtain channel from accidentally expanding or contracting due to vibration or gravity. It adapts to different sizes of workpieces 900 or changes in the position of the measuring point, ensuring that the lower end of the conical cover 320 always effectively covers the measuring reflector 130, maintains the air curtain seal, and ensures the stability of the channel shape during the measurement process.

[0078] Furthermore, please refer to Figure 4 , Figure 5 and Figure 6 Considering that temperature and humidity changes in the processing environment can easily cause moisture in the air curtain to condense on the inner wall of the elastic air curtain diaphragm 330, and that the size and location of the condensation are relatively random, thus affecting the consistency of the air curtain atmosphere in the air curtain channel for the propagation of the laser path, an anti-condensation module 600 is also included. The anti-condensation module 600 includes a drive motor 610 fixed on the mounting plate 110 and a toothed ring 630 rotatably embedded in the sealing sleeve 200. The output end of the drive motor 610 is equipped with a gear 620 that meshes with the toothed ring 630. The lower end of the toothed ring 630 is fixed with a scraper 650 through a connecting frame 640. The scraper 650 is in contact with the inner wall of the elastic air curtain diaphragm 330.

[0079] Specifically, when condensation occurs on the inner wall of the elastic air curtain diaphragm 330, the drive motor 610 drives the gear 620 to rotate. Under the meshing transmission of the gear 620 and the gear ring 630, the gear ring 630 and the connecting frame 640 rotate synchronously in the circumferential direction, thereby driving the scraper 650 to move circumferentially along the inner wall of the elastic air curtain diaphragm 330 to scrape off the condensation adhering to the inner wall of the elastic air curtain diaphragm 330, so as to keep the air curtain atmosphere inside the elastic air curtain diaphragm 330 consistent.

[0080] It should be noted that the scraper 650 is closely attached to the inner wall of the elastic air curtain diaphragm 330. Under the drive of the drive motor 610 through the meshing of the gear 620 and the gear ring 630, the scraper 650 is driven to move circumferentially along the inner wall, effectively scraping away the condensation water droplets randomly formed on the inner wall due to temperature and humidity changes, preventing the dew droplets from changing the local gas density or refractive index, and ensuring that the optical properties of the gas atmosphere in the air curtain channel are highly uniform.

[0081] By promptly removing condensation from the inner wall of the elastic air curtain diaphragm 330, the risk of local light path scattering, refraction anomalies, or beam distortion caused by random dew adhesion is eliminated, ensuring the stability of the propagation path and the consistency of the optical path of the laser measurement beam (from the laser head 120 to the measurement reflector 130 and back) within the air curtain channel.

[0082] Accordingly, please refer to Figure 5 and Figure 7 Considering that after the scraper 650 scrapes away the condensation on the inner wall of the elastic air curtain diaphragm 330, in order to prevent the condensation from falling onto the measuring reflector 130 below and affecting the accuracy of laser interferometry, the inner side of the conical cover 320 is provided with an annular drainage plate 370 adapted to the elastic air curtain diaphragm 330. A drainage groove is formed between the annular drainage plate 370 and the elastic air curtain diaphragm 330. A drainage channel 380 communicating with the bottom of the drainage groove is opened in the conical cover 320.

[0083] Specifically, after the scraper 650 scrapes away the condensation on the inner wall of the elastic air curtain diaphragm 330, the condensation falls into the drainage groove between the annular drainage plate 370 and the elastic air curtain diaphragm 330 under the action of gravity. Then the accumulated water is discharged through the drainage channel 380 to prevent the condensation water from directly contacting the measuring reflector 130.

[0084] The drainage groove formed between the annular drainage plate 370 and the elastic air curtain diaphragm 330 can accurately catch the condensation droplets scraped off by the scraper 650 from the inner wall of the elastic air curtain diaphragm 330. This design effectively prevents condensation from dripping directly onto the surface of the measuring mirror 130 below, preventing water stains from contaminating the reflective surface or forming an uneven liquid film, thus ensuring the optical cleanliness and reflection accuracy of the measuring mirror 130.

[0085] The bottom of the drainage channel is connected to the drainage channel 380 opened in the conical cover 320. The collected condensation water is automatically discharged into the system along the drainage channel 380 under the action of gravity, avoiding water accumulation at the bottom of the channel and eliminating the possibility of secondary interference to the measuring reflector 130 or the laser optical path caused by water shaking, evaporation or accidental dripping.

[0086] By quickly removing the condensation, the interior of the air curtain channel (especially the critical area near the measuring mirror 130) is kept dry for a long time, maintaining the purity and stability of the inert gas atmosphere. This ensures that the laser measuring beam is not affected by abrupt changes in refractive index or scattering caused by liquid water in its path toward / back to the measuring mirror 130, thus guaranteeing optical path consistency.

[0087] In further embodiments, please refer to Figure 8 and Figure 9The tooling module 700 includes a magnetic suction plate 710 for magnetically fixing the lower end face of the workpiece 900, and an inner support assembly 720 for radially expanding and fixing the inner wall of the workpiece 900.

[0088] Further, please refer to Figure 9 and Figure 10 The inner support assembly 720 includes a clamping cylinder 721 installed in the magnetic suction plate 710 and several sets of inner support plates 723 circumferentially distributed around the clamping cylinder 721. A lifting platform 722 is installed at the output end of the clamping cylinder 721. A connecting rod 724 is hinged between the lifting platform 722 and each inner support plate 723.

[0089] Specifically, the workpiece 900 is placed on the magnetic suction plate 710, which magnetically holds the workpiece 900 in place to prevent axial movement. Then, the clamping cylinder 721 drives the lifting platform 722 to descend. Under the transmission of the connecting rod 724, the inner support plates 723 are driven to expand radially outward. The inner wall of the workpiece 900 inside the inner support plate 723 provides radial support to prevent the workpiece 900 from radially shifting.

[0090] It should be noted that by applying a strong magnetic attraction force to the lower end face of the workpiece 900 through the magnetic suction plate 710, the axial movement or detachment of the workpiece 900 during the processing is effectively prevented; by driving the inner support plate 723 to expand radially outward through the inner support assembly 720, the inner support plate 723 is tightly supported against the inner wall of the workpiece 900, eliminating the radial displacement or vibration of the workpiece 900 caused by the processing force.

[0091] Magnetic fixation eliminates the need for complex alignment; the workpiece 900 is placed and initially fixed, simplifying the operation process. The clamping cylinder 721 drives the lifting platform 722 downward, and through multiple sets of symmetrical connecting rods 724, the circumferentially distributed inner support plates 723 expand radially synchronously and uniformly, ensuring that the workpiece 900 is subjected to balanced forces and avoiding local deformation or clamping stress concentration.

[0092] Furthermore, please refer to Figure 1 , Figure 2 and Figure 8 The processing module 800 includes a transverse moving component 810, a longitudinal moving component 820, a lifting component 830, and a processing component 840. The transverse moving component 810 includes a transverse moving guide rod 811 that is transversely fixed to the tooling module 700 and a transverse moving slider 812 that is slidably sleeved on the transverse moving guide rod 811. A transverse moving motor 813 is installed at one end of the transverse moving guide rod 811, and a transverse moving lead screw 814 that is threaded through the transverse moving slider 812 is connected to the output end of the transverse moving motor 813.

[0093] The longitudinal moving component 820 includes a longitudinal moving guide rod 821 longitudinally fixed to the transverse moving slider 812 and a longitudinal moving slider 822 slidably sleeved on the longitudinal moving guide rod 821. A longitudinal moving motor 823 is installed at one end of the longitudinal moving guide rod 821, and a longitudinal moving lead screw 824 threaded through the longitudinal moving slider 822 is connected to the output end of the longitudinal moving motor 823.

[0094] The lifting component 830 includes a lifting guide rod 831 vertically fixed on the longitudinal sliding block 822 and a lifting block 832 slidably mounted on the lifting guide rod 831. A lifting motor 833 is installed at one end of the lifting guide rod 831, and a lifting screw 834 threaded through the lifting block 832 is connected to the output end of the lifting motor 833.

[0095] The processing component 840 includes a processing motor 841 mounted on a lifting slider 832, and a milling disc 842 is detachably mounted on the lower end of the processing motor 841.

[0096] Specifically, through the independent three-axis drive and rigid guidance of the transverse component 810, the longitudinal component 820 and the lifting component 830, the workpiece 840 is precisely displaced in the X / Y / Z dimensions to perform milling on the upper surface of the workpiece 900.

[0097] The specific embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention, all of which are within the protection scope of the present invention.

Claims

1. A length measuring device based on laser interferometry, applied in a machining unit, the machining unit comprising a tooling module (700) for clamping a workpiece (900) and a machining module (800) for machining the workpiece (900); characterized in that, The length measuring device includes: A laser measurement module (100) includes a mounting plate (110) disposed on a processing module (800) and a measuring mirror (130) attached to a workpiece (900). A laser head (120) adapted to the measuring mirror (130) is mounted on the mounting plate (110), and a reference measuring mirror is built into the laser head (120). A sealing sleeve (200) is located outside the laser head (120); An air curtain channel module (300) is disposed on a sealing sleeve (200) for forming an air curtain channel between the laser head (120) and the measuring mirror (130); An air curtain construction module (400) is disposed on a sealing sleeve (200) for constructing an air curtain atmosphere within the air curtain channel; A channel adjustment module (500) is located outside the air curtain channel module (300) and is used to adjust the length of the air curtain channel; The air curtain channel module (300) includes a bellows (310) installed on the lower end face of the sealing sleeve (200) and an elastic air curtain diaphragm (330) coaxially distributed in the bellows (310). The upper end of the elastic air curtain diaphragm (330) is telescopically disposed in the sealing sleeve (200), and the lower end of the elastic air curtain diaphragm (330) is fixedly connected to the lower end of the bellows (310). The air curtain construction module (400) includes an air cavity (410) opened in the sealing sleeve (200), and a plurality of air jets (420) communicating with the air curtain channel are opened circumferentially on the inner side of the air cavity (410), and an air pipe (430) is connected to the outer side of the air cavity (410). The channel adjustment module (500) includes a mounting sleeve (530) disposed on the mounting plate (110) and a bearing seat (510) disposed on the air curtain channel module (300). A threaded rod (520) is rotatably mounted inside the bearing seat (510). The threaded rod (520) is threaded through the mounting sleeve (530), and a crank handle (540) is provided at the upper end of the threaded rod (520).

2. The length measuring device based on laser interferometry according to claim 1, characterized in that, The sealing sleeve (200) has an annular groove (340) inside, and a slip ring (350) is slidably embedded in the annular groove (340). A plurality of traction springs (360) connected to the slip ring (350) are arranged circumferentially inside the annular groove (340).

3. The length measuring device based on laser interferometry according to claim 1, characterized in that, The lower end of the corrugated pipe (310) is provided with a conical cover (320), and a flow guide (390) is provided on the inner side of the conical cover (320).

4. The length measuring device based on laser interferometry according to claim 1, characterized in that, It also includes an anti-condensation module (600), which includes a drive motor (610) fixed on the mounting plate (110) and a gear ring (630) rotatably embedded in the sealing sleeve (200). The output end of the drive motor (610) is equipped with a gear (620) that meshes with the gear ring (630). The lower end of the gear ring (630) is fixed with a scraper (650) through a connecting frame (640). The scraper (650) is in contact with the inner wall of the elastic air curtain diaphragm (330).

5. A length measuring device based on laser interferometry according to claim 3, characterized in that, The conical cover (320) is provided with an annular drainage plate (370) adapted to the elastic air curtain diaphragm (330) on the inner side. A drainage groove is formed between the annular drainage plate (370) and the elastic air curtain diaphragm (330). A drainage channel (380) communicating with the bottom of the drainage groove is opened in the conical cover (320).

6. The length measuring device based on laser interferometry according to claim 1, characterized in that, The tooling module (700) includes a magnetic suction plate (710) for magnetically fixing the lower end face of the workpiece (900), and an inner support assembly (720) for radially expanding and fixing the inner wall of the workpiece (900) is provided on the magnetic suction plate (710).

7. A length measuring device based on laser interferometry according to claim 6, characterized in that, The inner support assembly (720) includes a clamping cylinder (721) installed in the magnetic suction plate (710) and several sets of inner support plates (723) circumferentially distributed around the clamping cylinder (721). A lifting platform (722) is installed at the output end of the clamping cylinder (721), and a connecting rod (724) is hinged between the lifting platform (722) and each inner support plate (723).

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