Non-contact tool measuring device

Abstract

A non-contact tool measuring apparatus for use in a machine tool environment is described. The apparatus comprises an emitter (10) comprising a first aperture (46) and a laser (40) for generating light (44) which is emitted from the emitter (10) through the first aperture (46) towards a tool sensing region (69). A receiver (14) comprises an optical detector (62) and is arranged to receive light (44) from the tool sensing region (69). A processor (24) is also provided for analysing light detected by the optical detector (62) to enable measurements to be made of a tool (70) in the tool sensing region. The laser (40) is capable of generating light (44) having a wavelength of less than 590nm, whereby the size of the first aperture (46) can be reduced resulting in a reduction in contamination ingress. In one embodiment, the laser (40) generates blue light.

Description

[0001] This application is a divisional application. The original application is a PCT application with application number PCT / GB2019 / 052826, filed on October 7, 2019, which entered the Chinese national phase on April 8, 2021. The Chinese application number is 201980066435.7, and the title is "Non-contact tool measuring device". Technical Field

[0002] This invention relates to a non-contact tool measuring device and an associated tool measuring method. Specifically, this invention relates to an improved non-contact tool setter with broken beams for use in machine tool environments. Background Technology

[0003] Interrupted beam tool setting devices used on machine tools are known; for example, the NC4 non-contact tool setter is sold by Renishaw plc in Wotton-Under-Edge, England. This type of tool setting device includes a transmitter comprising a laser for generating a beam with a wavelength of approximately 700 nm. This beam is guided to a receiver through a free-space area where the tool can be placed. During the tool setting operation, the machine tool with the tool setter mounted is programmed to move the tool into and out of the beam. The interruption of the beam by the tool is detected by a detector included within the receiver module, and the device generates a so-called trigger signal whenever the beam is blocked by a certain amount. This allows the position of a portion of the tool (e.g., the tip or cutting edge) to be established, and can therefore be used to measure the length and / or diameter of the tool and monitor for tool breakage or wear.

[0004] The machine tool environment requiring a tool setting device is extremely harsh. In addition to metal chips and debris generated by the cutting operation, pressurized coolant jets are commonly used during the cutting process. For this reason, keeping any transparent optical windows undamaged or contaminated is very difficult. Therefore, tool setting devices for machine tools (such as the NC4 product mentioned above) emit and receive light through pinholes that allow unobstructed light transmission and also jet pressurized airflow to keep the device free from contaminants. Examples of this arrangement are described in US 6496273 and US 7312433.

[0005] While the aforementioned tool setting device typically functions reliably in most cases, the inventors have discovered that in some installations, contaminants can still enter through the orifice despite continuous air jetting.

[0006] It is also known to use "on-board" reflective (i.e., non-broken beam) tool detection devices, for example, as described in US2010 / 027031. Such devices are located away from the coolant flow present near the machine tool bed and direct light towards the tool located within the working volume of the machine tool. For this reason, such devices are less susceptible to contamination by coolant, etc., and may include a transparent window through which light is emitted and received. While such devices can detect the presence of a tool, they do not provide the measurement capabilities of a broken beam tool setting device. Summary of the Invention

[0007] According to a first aspect of the present invention, a non-contact tool measuring device for a machine tool is provided, the non-contact tool measuring device comprising:

[0008] The emitter includes a first aperture and a laser for generating light, the light generated by the laser being emitted from the emitter through the first aperture toward a tool sensing area.

[0009] A receiver, comprising an optical detector for detecting received light, the receiver being arranged to receive light from the tool sensing area, and

[0010] A processor is configured to analyze the light detected by the optical detector in order to measure the tool in the tool sensing area.

[0011] The transmitter and the receiver are arranged such that light emitted by the transmitter is transmitted directly to the receiver via the tool sensing area, thereby blocking the emitted light from the tool located in the tool sensing area.

[0012] The laser is characterized in that it can generate light with a wavelength of less than 590 nm.

[0013] Therefore, the present invention relates to a non-contact, beam-breaking tool measuring device for machine tools. As explained above, any device configured for use in the harsh environment of a machine tool must be quite robust and must be able to withstand the various contaminants (e.g., coolant and cutting debris) that will be exposed to during its service life. The device of the present invention includes a transmitter comprising a laser that generates light and an aperture through which the laser light is emitted. The emitted light is transmitted to a tool sensing area (i.e., an area in the space outside the tool measuring device). A receiver is also provided, comprising an optical detector (e.g., a photodiode) for detecting the received light. The receiver is arranged to receive light from the tool sensing area. When there is no tool in the tool sensing area, light is transmitted from the transmitter to the receiver. Specifically, the transmitter and the receiver are arranged such that the light emitted by the transmitter is transmitted directly to the receiver via the tool sensing area, thereby blocking the emitted light from a tool located in the tool sensing area. The light detected by the optical detector is analyzed by a processor, which allows measurement of a tool located in the tool sensing area (e.g., moving through the tool sensing area). Therefore, the associated machine tool can be programmed to move the tool into the tool sensing area, and the processor (e.g., by issuing a trigger signal) indicates to the machine tool that the tool is present. In this way, tool measurement is performed "on-machine".

[0014] The present invention is characterized in that the laser of the emitter generates light with a wavelength less than 590 nm. As explained below, the laser can have a fixed wavelength output within this wavelength range, or it can be tunable to output light within this wavelength range. The inventors have discovered several advantages of using light with a wavelength less than 590 nm compared to prior art devices using 700 nm light. Specifically, reducing the laser wavelength allows for the generation of a smaller beam, which in turn enables a smaller size of the first aperture through which light is emitted from the emitter. This smaller aperture reduces the ingress of contaminants, thereby improving the device's ability to withstand the harsh conditions within machine tool environments. As explained in more detail below, resistance to such contaminants is increased by more than 1.25 times when using light with a wavelength of 590 nm compared to using 700 nm light. In this way, a more robust and reliable tool setting device is provided.

[0015] The emitter preferably emits a light beam. The light beam is preferably substantially non-divergent. Lasers can inherently emit such a light beam. Advantageously, the emitter includes one or more optical elements (e.g., lenses, optical apertures, attenuators, and / or other elements) that act on the light generated by the laser to form a light beam emitted from the emitter through a first aperture. The light beam can have any cross-sectional profile; for example, it can have a substantially circular or elliptical cross-section.

[0016] The light beam can be substantially collimated, and may include a slightly divergent beam. Advantageously, the one or more optical elements are configured such that the light beam converges to a focal point within the tool sensing region. The advantage of using a focused beam is that the beam size within the tool sensing region can be minimized, allowing for the measurement of smaller tools. However, a disadvantage of such a tightly focused system is that it requires more precise alignment of multiple different optical components. Using a substantially collimated beam relaxes optical alignment tolerances, but reduces measurement accuracy, particularly for small tools.

[0017] As outlined above, the advantage of using shorter wavelengths of light is the ability to reduce the beam size, and thus the size of the aperture through which the beam passes and exits the emitter. Advantageously, the size of the first aperture is set to be the minimum size that allows the beam to pass through. In other words, the aperture is suitably shaped and constructed to be as small as possible without substantially attenuating the beam.

[0018] The tool setting device may include a venting function, in which air (or any other gas) is ejected from a first orifice in the emitter. The emitter is therefore preferably configured to emit pressurized gas (i.e., and a beam of light) through the first orifice. As explained above, this airflow helps prevent contaminants from entering. Using light with a shorter wavelength reduces the minimum permissible size of the first orifice, thereby reducing the amount of gas required to maintain the same venting rate from the first orifice.

[0019] Like the transmitter, the receiver may also include an aperture through which light is transmitted to an optical detector. In other words, the receiver preferably includes a second aperture through which received light is transmitted to the optical detector. The receiver is preferably configured to emit pressurized gas through the second aperture. Similar to the first aperture of the transmitter described above, the second aperture can be smaller when using light with shorter wavelengths. Therefore, a similar reduction in air consumption can be achieved for the receiver.

[0020] The laser can be a fixed-wavelength laser. The laser can be of any type. For the avoidance of doubt, the term "laser" as used herein should be understood to include laser diodes. Advantageously, the laser can be a diode laser (which is advantageous from a size perspective). The laser can include gallium nitride (GaN) laser diodes. The laser can include frequency adjustment components (e.g., frequency multipliers, etc.) to provide light of the desired wavelength. Alternatively, the laser can include a wavelength-tunable laser. A wavelength-tunable laser can be tuned to produce light with wavelengths less than 590 nm. However, it can also be tuned to output light with longer wavelengths. For example, for backward compatibility reasons, it may be possible to adjust to produce light with a wavelength of 700 nm. In this way, the wavelength can be adjusted as needed. When using light of different wavelengths, the aperture size can also be adjusted accordingly (e.g., by adapting or replacing the first and / or second aperture).

[0021] Preferably, the laser can generate light with a wavelength less than 550 nm. More preferably, the laser can generate light with a wavelength less than 500 nm. More preferably, the laser can generate light with a wavelength less than 450 nm. More preferably, the laser can generate light with a wavelength less than 420 nm. The laser can conveniently generate light with a wavelength of approximately 400 nm. The laser can output light in the green or blue portion of the spectrum. The laser can output light in the blue portion of the spectrum. The laser can output light in the ultraviolet (UV) portion of the spectrum. The laser can be visible to the human eye. The wavelength of the laser can be shorter than the wavelength visible to the human eye. As explained below, the shorter the wavelength, the greater the resistance to contaminants and the less gas (air) required (i.e., in the case of an venting arrangement). Conveniently, the wavelength is at least 400 nm (i.e., above 400 nm). For laser safety reasons, a wavelength of 400 nm or higher is preferred. Specifically, lasers that emit light with wavelengths greater than 400 nm are typically permitted to operate at higher output power than short-wavelength lasers, while not exceeding “Class 2” status (as defined in BSI standard publication BS EN60825-1:2014 “Safety of Laser products”).

[0022] The transmitter may include a single laser. Alternatively, multiple lasers may be used. If multiple lasers are used, they can output light of different wavelengths. An optical detector can be configured to sense or receive light from only one of the multiple lasers (e.g., a filter can be used to correlate the beam intensity signal with the light received from one laser). In a preferred embodiment, as described above, the laser of the transmitter (the master laser or the metrology laser) can be used for tool measurement. The master laser can operate at a short wavelength (e.g., 400 nm) to provide optimal measurement performance.

[0023] The emitter may include an additional targeted or directional light source (e.g., an LED, a white light source, or the aforementioned additional laser) for generating additional light. The additional light source may be a monochromatic light source. The wavelength of the additional light may be in the visible light band (e.g., red or green light to which the eye is most sensitive) and / or different from the wavelength of the laser. The additional light may exit the emitter through a laser aperture (i.e., the same aperture through which the light emitted by the laser passes), or a separate aperture may be provided in the emitter for outputting the light generated by the light source. Conveniently, the additional light generated by the light source substantially coincides with the light generated by the (main) laser. Advantageously, the beam generated by the laser overlaps with the light from the light source. In this way, the visibility of the path of the light emitted by the emitter to the user is improved. This improved optical path visibility can help manually verify correct tool setting operations.

[0024] The processor is configured to analyze the light intensity detected by the optical detector. For example, the optical detector may generate a beam intensity signal that is transmitted to the processor. The optical detector may include a photodiode. The optical detector includes a photodiode having a single photosensitive region. The optical detector may include multiple sensing elements. The optical detector may include a sensor array. For example, the optical sensor may include a 2D sensor array (such as a CCD). The processor can perform any suitable analysis on the output of the optical detector. This analysis may include image analysis. Preferably, the processor is arranged to monitor the light intensity detected by the optical detector and send a trigger signal when the detected light intensity exceeds a predetermined threshold. The machine tool can then use the trigger signal to measure desired tool characteristics; such measurements are known in the art and therefore will not be explained in more detail here. In one embodiment, the device may be a tool setting device as described in our international patent application PCT / GB2018 / 052600.

[0025] The transmitter and receiver are arranged in a transmissive or "beam-broken" configuration. Specifically, light emitted by the transmitter is transmitted directly to the receiver via a tool sensing area. The tool located in the tool sensing area will thus block the emitted light. This light blocking is monitored to allow for tool measurement. This transmissive mode is particularly suitable for tool setting (i.e., measuring tool dimensions, such as length) and tool breakage detection. The tool measurement device can be a tool setting and / or tool analysis device. The device may include a transmitter and a receiver, which are separately mounted to different parts of the machine tool. In this case, the transmitter and receiver are aligned with each other during installation. Advantageously, the transmitter and receiver are formed as part of an integral unit. For example, the transmitter and receiver of the device may both be attached to a common base that can be mounted to the machine tool. In this way, the alignment of the transmitter and receiver can be completed during manufacturing. The processor may be integrated into the transmitter and / or receiver and / or any common base, or it may be set as a separate unit.

[0026] According to a second aspect of the invention, a method for measuring a tool on a machine tool is provided, the method comprising the steps of: (i) using a laser to transmit a light beam through a tool sensing area within the machine tool workspace; (ii) using an optical detector to receive light from the tool sensing area, the light beam from the laser being directly transmitted to the optical detector via the tool sensing area; and (iii) monitoring the light detected by the optical detector to measure a tool located in the light beam, characterized in that the wavelength of the light beam is less than 590 nm. The method may include any features or characteristics of the corresponding equipment described above.

[0027] This document also describes a non-contact tool measuring device for machine tools, which includes an emitter for generating and emitting light, wherein the emitter includes a wavelength-tunable laser. The device may also include any one or more features, individually or in combination, which are also described herein.

[0028] This document also describes a non-contact tool measuring device for machine tools, comprising a transmitter having a first laser for generating a first beam, wherein the device further comprises a second light source (e.g., a second laser) for generating a second beam with a different wavelength than the first beam. The first and second beams may be arranged to coincide. The first beam may have a wavelength less than 590 nm (e.g., it may be blue light). The second beam may have a more readily visible wavelength (e.g., it may be red or green). The device may also include any one or more features, individually or in combination, which are also described herein.

[0029] This document also describes a non-contact tool measuring device for machine tools. The device may include a transmitter. The transmitter may include a first aperture. The transmitter may include a laser for generating light. The light generated by the laser may be emitted from the transmitter through the first aperture toward a tool sensing area. A receiver may be provided. The receiver may include an optical detector for detecting the received light. The receiver may be arranged to receive light from the tool sensing area. A processor may also be provided. The processor may be used to analyze the light detected by the optical detector. This enables measurement of the tool in the tool sensing area. The laser is capable of generating, or configured to generate, light with a wavelength less than 590 nm. When no tool is present in the tool sensing area (i.e., in a beam-off configuration), light can be transmitted from the transmitter to the receiver. Alternatively, light reflected from a tool located in the tool sensing area can be received by the receiver. For example, the device may include a transmitter and receiver arranged in a reflection configuration. In this configuration, when no object is present in the tool sensing area, the light emitted by the transmitter is not received by the detector. However, the light reflected from the tool located in the tool sensing area is received by the receiver. This reflection mode is particularly suitable for inspecting the presence and characteristics of cutting tools. The device may also include any one or more features, either individually or in combination, which are also described herein. Attached Figure Description

[0030] The invention will now be described by way of example only, with reference to the accompanying drawings, in which;

[0031] Figure 1 A non-contact tool setting device that can be mounted on machine tools was demonstrated.

[0032] Figure 2 Showing more details Figure 1 The arrangement of the transmitter and receiver in the non-contact tool setting device, and

[0033] Figure 3 This demonstrates how shorter wavelength laser sources can be used to reduce contaminant entry and air consumption. Detailed Implementation

[0034] refer to Figure 1 This provides a schematic illustration of the tool-setting apparatus of the present invention. The apparatus includes an emitter 10 for generating a light beam 12 with a wavelength of 400 nm (i.e., the beam includes blue light). The emitter 10 uses a laser diode and suitable optics to generate the light beam 12; these do not... Figure 1 As shown in the figure, but the following will refer to Figure 2 To describe in more detail. Receiver 14 is also shown for receiving beam 12. The receiver includes a photodiode (not shown) for detecting beam 12.

[0035] Both transmitter 10 and receiver 14 are attached to a common base 20 via supports 18. This arrangement ensures that transmitter 10 and receiver 14 maintain a fixed spacing and orientation relative to each other. The base 20 can then be directly mounted to the machine tool bed or even any suitable part. It should also be noted that a variety of different alternative structures can be used for mounting the transmitter and receiver. For example, a common housing for the transmitter and receiver can be provided, or separate transmitter and receiver units can be mounted separately to the machine tool.

[0036] The device also includes an interface 15, which connects to the transmitter 10 and receiver 14 via cable 17. Interface 15 provides power to the transmitter 10 and receiver 14 and also receives the beam intensity signal from a photodiode detector of receiver 14. Interface 15 also includes a processor 24 that analyzes the beam intensity signal and generates a trigger signal whenever a trigger threshold (e.g., 50%) is exceeded. This trigger signal is transmitted via cable 28 to the SKIP input of the controller 30 of the associated machine tool. In use, a tool moving into the beam via the associated machine tool causes the beam intensity signal to drop. When the beam intensity signal exceeds the trigger threshold, a trigger signal is sent to the machine tool, and upon receiving the trigger signal, the tool position measured by the machine tool is captured. In this way, the tool position can be determined, thereby allowing tool dimensions (e.g., tool length or diameter) to be established. Further details regarding how the beam intensity signal is processed to determine the presence of a tool are described, for example, in US 6878953 and US 7315018.

[0037] Next reference Figure 2 The internal configuration of transmitter 10 and receiver 14 is shown in more detail.

[0038] Emitter 10 includes an emitter housing 38 that houses a laser diode 40 and a focusing optics 42. In this embodiment, the laser diode 40 is a 1mW (laser class 2) gallium nitride (GaN) laser diode emitting radiation with a wavelength of approximately 400 nm. The light generated by the laser diode 40 is focused into a beam 44 by the focusing optics 42 and exits the emitter 10 through an aperture 46 formed in the emitter housing 38. Although not shown, other optical components (e.g., optical apertures for clipping or shaping the laser beam, filters, beam attenuators, etc.) may be included if necessary. The beam 44 has a substantially circular cross-sectional profile, and the aperture 46 has a similar cross-sectional profile, and its dimensions are appropriately determined (i.e., its diameter d) to be slightly larger than the beam 44. In this way, the beam 44 can exit the aperture 46 with substantially no attenuation. A supply of pressurized air (indicated by arrow 48) is introduced into the cavity of the emitter housing 38 and discharged through the aperture 46 (as indicated by arrow 50). This venting is designed to prevent as much cutting debris, coolant, and other contaminants as possible from entering the launcher housing.

[0039] Receiver 14 includes a receiver housing 60, which includes a photodiode 62. Light entering the receiver housing 60 through aperture 66 falls on the photodiode 62. The photodiode 62 is configured to be sensitive to light with a wavelength of 400 nm. Although not shown, a suitable wavelength filter may also be included to prevent light other than 400 nm from reaching the photodiode 62. A pressurized air supply (indicated by arrow 65) is introduced into the cavity of the receiver housing 60 and discharged through aperture 66 (indicated by arrow 68). As described above, this venting is intended to prevent cutting debris, coolant, etc., from entering the receiver housing as much as possible.

[0040] The transmitter 10 and receiver 14 are positioned relative to each other such that a light beam 44 emitted from the transmitter 10 is transmitted to the receiver 14. The size of the aperture 66 in the receiver housing 60 is set to be as small as possible while still allowing the light beam to pass through. A free space region is provided between the transmitter 10 and the receiver 14 to allow the light beam to pass through. The light beam 44 is focused in the tool sensing region 69. In use, the tip of the tool 70 moves downward into the tool sensing region 69; this blocks the light beam and sends a trigger signal, thereby allowing the measurement of the length of the tool 70. The beam diameter is minimized within the tool sensing region 69, thus allowing for the most accurate measurement of the tool size.

[0041] As explained above, prior art tool setting devices include lasers that emit red light (typically, with a wavelength of 700 nm). Using shorter wavelength light (such as the 400 nm light in this embodiment) has many advantages. Specifically, compared to longer wavelength (red) light, shorter wavelength (blue) light can be focused into a smaller spot, thus enabling the measurement of tool dimensions with higher accuracy. Importantly, using shorter wavelength (e.g., blue) light also allows for the formation of smaller apertures in the transmitter housing and / or receiver housing, because for a given focal spot size, the beam can have a smaller cross-section. Using a smaller aperture not only reduces the air consumption required to maintain airflow at a certain velocity through the aperture but also reduces the entry of contaminants (coolant, debris, chips, dust, etc.) into the device through the aperture. Furthermore, the combination of blue light and a smaller aperture also reduces the amount of stray light that causes noise in the beam intensity signal.

[0042] refer to Figure 3 This demonstrates the effects of using different wavelengths of light on pollutant entry and air consumption. Specifically, Figure 3 The horizontal axis represents the wavelength of light, while the vertical axis represents the reduction factor. As explained above, reducing the wavelength reduces the minimum achievable beam size and, consequently, the size of the aperture through which the beam passes. Line 100 shows the factor by which air consumption decreases as the wavelength decreases from 700 nm (this factor is defined as one for 700 nm). This assumes that the volumetric flux (i.e., the amount of air ejected per square millimeter of aperture) remains constant. Line 102 shows the reduction in particle entry according to wavelength; this reduction in particle entry is due to the reduction in aperture area (i.e., the size of the opening through which contaminants can pass), and also takes into account the particle size distribution generated during a typical cutting process (i.e., the aperture blocks particles larger than the aperture size from entering).

[0043] from Figure 3 It can be seen that using a wavelength of approximately 590 nm instead of 700 nm means a reduction in particle entry by a factor of 1.25, and air consumption is similarly reduced. Further reducing the wavelength to approximately 550 nm reduces particle entry by a factor of 1.5, with a slightly smaller reduction in air consumption. Using a wavelength of 500 nm results in a reduction factor of 2 (i.e., half the particles can enter), while at a wavelength of 400 nm, the reduction is greater than 3. These figures are based on the assumption that light at a wavelength of 700 nm requires a 0.45 mm aperture, and the finding that the aperture can be halved to 0.25 mm when using a wavelength of 400 nm.

[0044] The particle size distribution used in this analysis is taken from the following paper: Mathew J. Hess & S. Komar Kawatra (1999) Environmental Beneficiation of Machining Wastes—Part I: Material Characterization of Machining Swarf, Journal of the Air & Waste Management Association, 49:2, 207-212, DOI:0.1080 / 10473289.1999.10463783.

[0045] Therefore, the above embodiments highlight the advantages of using a tool-setting device that operates with light at wavelengths less than 700 nm. It should be remembered again that these are merely examples, and other embodiments are possible. For example, the laser diode may be a wavelength-tunable laser (e.g., the laser diode may be adjustable to emit light in the range of 400 nm to 670 nm or any wavelength range described herein). In this way, the device can be configured to use different wavelengths of light for different applications. Although a single laser has been described, it is also possible to have emitters comprising multiple lasers. These lasers may have different wavelengths. For example, the device may include a blue laser (e.g., with a wavelength below 400 nm) and a red laser (e.g., 700 nm). In this way, measurements can be performed using light of different wavelengths. Alternatively, one laser (e.g., a blue laser) may be used for measurement purposes, while lasers with different wavelengths (e.g., green or red lasers) can provide a more visible beam for the operator. In this example, the beams emitted by the different lasers may be arranged to substantially overlap. Any suitable monochromatic light source can be used instead of the laser. Furthermore, while simple holes have been shown above, these holes can include angled vents to allow air to be ejected in a direction that does not coincide with the optical path of the beam (e.g., according to US 6496273). Those skilled in the art will also recognize possible variations of the above embodiments upon reading this specification.

Claims

1. A non-contact tool measuring device for machine tools, comprising: The transmitter includes a first aperture and a first laser for generating a first beam of light emitted from the transmitter through the first aperture toward a tool sensing area. A receiver, comprising a second aperture and an optical detector for detecting received light, is arranged to receive a first light beam from the tool sensing area, the received first light beam being transmitted through the second aperture to the optical detector, and... The transmitter and the receiver are arranged such that a first light beam emitted by the transmitter passes through the tool sensing area to the receiver, whereby a tool located in the tool sensing area blocks the emitted first light beam, and when no tool is present in the tool sensing area, the first light beam is transmitted from the transmitter to the receiver. The transmitter includes a second light source for generating a second beam with a wavelength different from that of the first beam, and the transmitter is configured such that the second beam substantially coincides with the first beam.

2. The device according to claim 1, wherein, The second light source is capable of producing light in the visible light band.

3. The device according to claim 1, wherein, The second light source includes a second laser.

4. The device according to claim 1, wherein, The first laser is capable of producing light with a wavelength of less than 590 nm.

5. The device according to claim 1, wherein, The first laser is capable of producing light with a wavelength of less than 500 nm.

6. The device according to claim 1, wherein, The first laser is capable of producing light with a wavelength of less than 420 nm.

7. The device according to claim 1, wherein, The first laser is capable of generating ultraviolet light.

8. The device according to claim 1, wherein, Both the first beam and the second beam can be used for tool measurement.

9. The device according to claim 1, wherein, The second beam is more visible to the operator than the first beam.

10. The device of claim 1, further comprising a processor configured to analyze light detected by the optical detector to send a trigger signal indicating the moment of interruption or resumption of light transmitted from the transmitter to the receiver.

11. The device according to any one of claims 1 to 10, wherein, The transmitter is configured to emit pressurized gas through the first port, and the receiver is configured to emit pressurized gas through the second port.

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