FR2994116A1 - Laser head, useful for e.g. cutting and welding solid material, includes gas supply, housing with inlet, outlet and openings for entry of gas, optical system, and transparent separator, and switch placed between gas supply and opening - Google Patents

Abstract

The laser head comprises a laser source (2), a gas supply (3), a housing (4), and an optical system (5) disposed within the housing. The housing includes an inlet for laser beam, and a nozzle outlet. The optical system and the outlet are spaced apart by a cavity. The laser head further comprises a transparent separator for separating the liquid-tight cavity into a dry cavity and a floodable cavity, a position sensor, a differential pressure sensor, and a lever that manually moves the separator between open and closed positions. The laser head comprises a laser source (2), a gas supply (3), a housing (4), and an optical system (5) disposed within the housing. The housing includes an inlet for laser beam, and a nozzle outlet. The optical system and the outlet are spaced apart by a cavity. The laser head further comprises a transparent separator for separating the liquid-tight cavity into a dry cavity and a floodable cavity, a position sensor, a differential pressure sensor, and a lever that manually moves the separator between open and closed positions. The dry cavity and floodable cavity are present in fluid communication with each other in the open position, and the dry cavity is sealingly separated from the floodable cavity in the closed position. The housing comprises a first outer opening for entry of gas inside of the dry cavity and a second opening for entry of gas into the floodable cavity. The gas supply is connected to first opening and second opening. A switch is placed between the gas supply and the second opening. The separator includes a slide and a plate guided by the slide. The separator is coupled to the sensor so that the sensor detects the position of separator during operation of the laser head. The laser source and the position sensor are coupled so that the laser source emits a laser beam when the separator is present in the open position. The differential pressure sensor measures the pressure difference between the dry cavity and floodable the cavity during operation of the laser head. The separator is further coupled with the differential pressure sensor so that the displacement of the separator between the open position opening and the close position is ordered by the measurement of the differential pressure between the dry cavity and the floodable cavity, the separator is maintained in the closed position when the differential pressure sensor indicates a pressure in the dry cavity lower than a pressure in the floodable cavity and is maintained in the open position when the differential pressure sensor indicates the pressure in the dry cavity higher than or equal to the pressure in the floodable cavity. The separator and the switch are coupled so that the switch prevents the passage of gas into the floodable cavity when the separator moves from the open position to the closed position.

Description

TECHNICAL FIELD The present invention relates to the field of laser heads. More particularly, the present invention relates to the field of laser heads comprising a laser source, a housing and an optical system disposed within the housing, the housing comprising a laser beam input port and a nozzle exit port, the optical system and the nozzle outlet being spaced from one another by a cavity. State of the art Laser heads are commonly used for cutting, welding, cleaning, stripping, machining and etching of solid materials. A laser head includes a laser source, a housing, and an optical system disposed within the housing, the housing including a laser beam input port and a nozzle exit port. In operation, the laser source emits a laser beam that enters the housing through the inlet port, passes through the optical system, and exits through the nozzle outlet. The optical system includes sensitive components whose surfaces must be kept drastically clean. This means that they must not be put in direct contact with the fluid (gas or liquid) of the external environment in which they bathe because this fluid is likely to pollute and cause their damage. For this, the optical system, and in particular the last element in the direction of the laser beam, is generally isolated from the external medium by a coaxial gas flow that emerges with the laser beam through the nozzle outlet orifice. This thus prevents the penetration of the fluid from the outside environment and pollutants that it can contain inside the housing. The gas flow must be maintained as long as the laser head is immersed in the fluid of the external environment.

When the fluid of the external medium is gas, generally transparent, it does not prevent direct or remote visual observation using a camera, endoscope, fiberscope or other similar devices.

Visual observation is necessary to control the position of the laser head in relation to the material to be worked or to check the quality of the operation without the laser head needing to be removed. For example, during a cutting operation with the laser head, it is not possible to follow continuously the progression of the cut, so it becomes important to be able to observe the correct relative position of the laser head with respect to the material to be cut. cutting to program by learning the cutting paths to be executed or for the registration of predefined trajectories.

Another example, visual observation of the state of the surfaces of the treated material after the operation performed with the laser head can verify the quality of the operation without the need to move the laser head away. For cutting, the observation of a slit that does not show slag on its banks in the face (worked face) is characteristic of a quality cut. However, when the external medium fluid is a liquid, ejecting the gas through the nozzle outlet to the outside medium generates bubbles, making visual observation impossible. This is all the more difficult because it is done remotely.

In order to circumvent the need to visually observe the position of the laser head relative to the material to be worked, different location systems can be used to estimate the distance between the laser head and the material, for example the electromagnetic or optical proximity sensors.

However, the information provided by this type of system is one-dimensional. This information is generally very localized, for example according to the direction of the laser beam (firing axis). Consequently, they are less rich than those provided by a two or three dimensional visual observation and their interpretation is delicate.

Visual observation of the work area can be further accomplished using an observation device through the nozzle exit port, typically a coaxial sighting device using a semireflecting mirror. Visual observation can still be performed by cameras located within the dry zone created by sealing devices such as skirts, joints, or water curtain projection. However, in this case, the visualization is only local and limited within a dry zone delimited by the protected space portion of the liquid of the external medium by the gas flow. Moreover, the use of such laser heads induces a large consumption of gas. Indeed, the gas ejection through the nozzle outlet orifice must be maintained at all times, even when the laser beam is not emitted.

Presentation An objective aims to overcome at least one drawback of the prior art presented above.

In particular, one objective is to allow visual observation in a liquid medium. Another goal is to reduce gas consumption. By this, there is provided a laser head comprising a laser source, a gas supply, a casing and an optical system disposed inside the casing, the casing comprising a laser beam entry port, a discharge orifice of nozzle, the optical system and the nozzle outlet being spaced from one another by a cavity, characterized in that it further comprises a liquid-tight separator separating the cavity into a dry cavity and a cavity floodable, the separator comprising two positions, an open position, in which the dry cavity and the floodable cavity are in fluid communication, and a closed position, in which the dry cavity is sealed from the floodable cavity, and in that the housing further comprises a first gas inlet port within the dry cavity and a second gas inlet port in the floodable cavity, the gas supply being connected to the first port and the second port, a switch being disposed between the gas supply and the second port.

With such a laser head, it is possible to reduce the gas consumption. Indeed, the watertight separator makes it possible to protect the optical system of the liquid from the external environment. Thus, it is no longer necessary to continuously eject gas through the nozzle outlet. When no laser beam is emitted, it suffices simply to position the separator in its closed position and to stop the flow of gas into the flood cavity. Moreover, since it is no longer necessary to constantly eject gas through the nozzle outlet orifice, it is possible to observe directly or remotely using a camera, endoscope, fiberoptic or other devices. similar the working area when the separator is disposed in its closed position and the gas ejection is stopped, because there is no bubbles. Thus, it is possible to follow the positioning of the laser head relative to the material to be worked and to check the state of the impacted surfaces before and after the operation performed by the laser head with less displacement of the laser head. The separator is preferably transparent. The separator may further comprise a slider and a movable plate relative to the slider, for example between the closed position and the open position. The laser head may further comprise a position sensor, and the separator may be coupled to the sensor so that the sensor detects the position of the separator during operation of the laser head. The laser source and the position sensor can be coupled so that the laser source emits a laser beam only when the separator is in the open position. The laser head may further comprise a differential pressure sensor for measuring the pressure difference between the dry cavity and the floodable cavity during operation of the laser head. The separator may further be coupled to the differential pressure sensor so that the displacement of the separator between the open position and the closed position is controlled by measuring the differential pressure between the dry cavity and the flood cavity. the separator being held in the closed position as long as the differential pressure sensor indicates a pressure in the dry cavity less than a pressure in the flood cavity, the separator being moved into the open position when the differential pressure sensor indicates a pressure in the dry cavity greater than or equal to the pressure in the floodable cavity. The laser head may also include a lever for manually moving the separator between the open position and the closed position. The switch and the separator can be coupled so that the switch prevents the flow of gas into the flood cavity when the separator moves from your open position to the closed position. Presentation of the Figures Other objectives, features and advantages will emerge from the detailed description which follows with reference to the single FIG. 1 given for illustrative and non-limiting purposes, and which shows schematically a laser head according to the invention.

DETAILED DESCRIPTION With reference to FIG. 1, a laser head according to the invention is described below. The laser head 1 comprises a laser source 2, a gas supply 3, a casing 4 and an optical system 5 disposed inside the casing 4. The casing 4 comprises a laser beam entry port 41, an aperture of nozzle outlet 42, a first gas inlet port 45 and a second gas inlet port 46. The gas supply 3 is connected to the first orifice 45 and to the second orifice 46.

The optical system 5 and the nozzle outlet port 42 are spaced from each other by a cavity. The laser head 1 further comprises a liquid-tight separator 6 separating the cavity into a dry cavity 43 and a flood cavity 44. The dry cavity 43 has the first gas inlet port 45 and the flood cavity 44 has the second orifice 46 gas inlet. The dry cavity 43 is a cavity housing the optical system 5. This dry cavity 43 is kept constantly out of contact with the external environment.

Thus, the optical system 5 is continuously protected from possible pollution or degradation. The floodable cavity 44 is a cavity that can receive the fluid from the external medium, for example a gas or a liquid. The fluid from the outside medium can be expelled through the nozzle outlet 42 by gas injection through the second gas inlet port 46. The separator 6 has two positions, an open position, in which the dry cavity 43 and the flood cavity 44 are in fluid communication, and a closed position, in which the dry cavity 43 is sealed from the cavity floodable 44.

The separator 6 is preferably transparent to allow visual observation by means of an observation device disposed inside the dry cavity 43, for example a coaxial observation device. The separator 6 may comprise a slider 61 and a plate 62 movable relative to the slider between the open position and the closed position. For example, the plate 62 can be mounted in translation and / or in rotation relative to the slide 61. A switch 7 is disposed between the gas supply 3 and the second orifice 46. This switch 7 has at least two positions a first position permitting the passage of the gas from the gas supply 3 to the floodable cavity 44 and a second position preventing the passage of the gas from the gas supply to the floodable cavity 44. The laser head 1 can further comprise 8. The separator 6 is then coupled to the position sensor 8 so that the position sensor 8 detects the position of the separator 6 during the operation of the laser head. For example, the position sensor 8 comprises two switches 81, 82 with flexible blades controlled by permanent magnet and the separator 6 comprises at least two permanent magnets 63, 64 which will act on the switches 81, 82 with flexible blades: a permanent magnet 64, and a closing permanent love 63. Each switch 81, 82 with flexible blades has two states; it then operates in binary with a first state (0) and a second state (1). The switch 81, 82 with flexible blades is normally in its first state (0). A permanent magnet can change the state of the reed switch 81, 82 from its first state (0) to its second state (1). The permanent magnets 63, 64 are arranged at two locations chosen in the following manner.

When the separator 6 is in its closed position, the permanent closing magnet 63 is facing a switch 81 with flexible blades, said closing switch. The closing switch 81 then changes from its first state (0) to its second state (1). The position sensor 8 then indicates that the separator 6 is in its closed position.

As for the other switch 82 with flexible blades, said opening switch, it is in its first state (0). When the separator 6 is in its open position, the permanent opening magnet 64 is opposite the opening switch 82. The opening switch 82 then changes state, from its first state (0) at its second state (1). The position sensor 8 then indicates that the separator 6 is in its open position. As for the closing switch 81, it is in its first state (0). This can be illustrated in the case where the separator 6 comprises a slider 61 and a plate 62 movable relative to the slider 61 between a closed position and an open position. For example, the plate 62 is mounted in translation, possibly from bottom to top and vice versa with respect to the slide 61. The slide 61 then comprises an opening 611 aligned with the optical system 5 and the nozzle outlet 42 The plate 62 comprises an operting part 621 (for example the upper part) and a passing part 622 (for example the lower part). Furthermore, the plate 62 also comprises a permanent opening magnet 64 on its upper edge and a permanent closure magnet 63 on its lower edge. The switch 82 with flexible opening blades is disposed at the top of the slide 61 and the switch 81 with flexible closing blades at the bottom of the slider 61. When the plate 62 is disposed in the lower position, the sealing portion 621 closes the opening 611 of the slider sealingly, sealingly separating the dry cavity 43 from the floodable cavity 44. Furthermore, in this position of the plate 62, the permanent closure magnet 63 is located opposite the switch 81 with flexible closing blades which causes the indication that the separator 6 is in the closed position. When the plate 62 is disposed in the high position, the passing portion 622 discovers the opening 611 of the slide, then putting the dry cavity 43 and the floodable cavity 44 in fluid communication. Furthermore, in this position of the plate 62, the permanent opening magnet 64 is located opposite the switch 82 with flexible opening blades which causes the indication that the separator 6 is in the open position. The position of the separator 6 can be detected and for example indicated by a visual or audible signal. This allows the user to know when the separator 6 is in its closed position and when the gas supply to the flood cavity 44 can then be cut off. This also allows the user to know when the emission of the laser beam can be triggered, thus avoiding the damage of the separator 6 by the laser beam, which would also cause projections in the dry cavity 43 which would in turn damage the optical system 5. The laser head 1 may further comprise a differential pressure sensor 9 for measuring the pressure difference between the gas supply pressure and that prevailing in the external environment during operation of the laser head 1. The measured pressure differential can be indicated by either a visual or audible signal. Thus, the user can know when the gas supply pressure (corresponding to the pressure prevailing in the dry cavities 43 and floodable 44) is greater than the pressure prevailing in the external environment. In which case, the separator 6 can be moved from its closed position to its open position by means of, for example, a lever, since the fluid, and in particular the liquid, of the external medium has been driven out of the housing by the The differential pressure sensor 9 measures the pressure of the gas supply, for example, by means of a measuring orifice 47 provided on the housing 4, at the exit of which (ie ie outside the housing) the differential pressure sensor 9 is arranged. It thus measures the pressure prevailing in the flood cavity 44, the pressure of which is equal to that of the gas supply when the fluid of the external medium is completely expelled from it, and the pressure prevailing in the external environment. In order to protect the separator 6 from the projections generated by the work carried out on the material M, the casing 4 is provided with a particular shape constituting a baffle. For example, the housing 4 is designed to have a nozzle outlet 42 of reduced size. In longitudinal section, as shown in Figure 1, the casing 4 then has a funnel-shaped side of the outlet nozzle 42, the largest section being included in the flood cavity 44 and the smallest section being the outlet nozzle 42 same. In order to automate the operation of the laser head 1, one or more commands may be provided. The laser source 2 and the position sensor 8 can be coupled via a transmission control 13 so that the laser source 2 emits a laser beam only when the separator 6 is in the open position. The two-position switch 7 can also be coupled to the position sensor 8 via a gas injection control 11 so as to prevent the passage of gas from the gas supply 3 to the flood cavity 44 when the separator 6 becomes moves from its open position to its closed position. Similarly, the separator 6 can be coupled to the differential pressure sensor 9 via an open / close command 12 so that the movement of the separator 6, between the open position and the closed position, is controlled. by measuring the differential pressure between the pressure of the gas supply 3 and that of the external medium. In this case, the separator 6 is kept in the closed position as long as the differential pressure indicates a gas supply pressure (eg the pressure in the flood cavity 44) lower than the pressure in the external environment. The separator 6 is moved to your open position when the differential pressure indicates a gas supply pressure higher than the pressure in the external environment. For example, the separator 6 comprises a slider 61 and a plate 62 housed in the slider 61. The slider comprises two ends between which the plate 62 moves between an open position and a closed position. Displacement is achieved by a closing control gas supply line 15 and an opening gas supply line 16. A first end 151 of the closing control gas inlet pipe 15 is connected to a first end of the slide 61, called the closing end 612, and a first end 161 of the control gas inlet pipe 16. opening is connected to a second end of the slider 61, said opening end 613. The second ends 152 of the closing gas supply line 15 and the second end 162 of the gas supply pipe 16 Opening control is connected to the open / close control 12, forming the outputs thereof. The opening / closing command 12 receives gas input from the gas supply 3.

As long as the differential pressure sensor 9 indicates a gas supply pressure lower than the pressure in the external environment, the opening / closing control 12 allows the gas to pass into the closing control gas supply line. . This has the consequence that the plate 62 is pushed by the gas entering from the closing end 612 of the slider 61 towards its closed position. When the differential pressure sensor 9 indicates a gas supply pressure higher than the pressure in the external environment, the opening / closing control 12 switches to allow the gas to pass through the control gas supply line 16. opening. This has the consequence that the plate 62 is pushed by the gas entering from the opening end 613 of the slider 61 towards its open position.

The laser source 2 can also be coupled to the separator 6 via a closing command, so that the separator 6 is moved from its open position to its closed position once the laser source 2 is extinguished.

The commands can be combined into one element and perform one or more of the automations presented above. The control can also be a system comprising unitary control modules, each unit control module being able to manage one or more of the automations presented above.

Claims (9)

REVENDICATIONS1. Laser head (1) comprising a laser source (2), a gas supply (3), a housing (4) and an optical system (5) disposed inside the housing (4), the housing (4) comprising a laser beam inlet port (41), a nozzle outlet port (42), the optical system (5) and the nozzle outlet port (42) being spaced apart from one another by a cavity, characterized in that it further comprises a liquid-tight separator (6) separating the cavity into a dry cavity (43) and a floodable cavity (44), the separator (6) comprising two positions, a position of opening, in which the dry cavity (43) and the flood cavity (44) are in fluid communication, and a closed position, wherein the dry cavity (43) is sealed from the flood cavity (44), and in that the housing further comprises a first gas inlet port (45) within the dry cavity (43) and a second port (46) of gas feed into the flood cavity (44), the gas supply (3) being connected to the first port (45) and the second port, a switch (7) being disposed between the gas supply (3) and the second port (46). 2. laser head (1) according to claim 1, wherein the separator (6) is transparent. 3. Laser head (1) according to claim 1 or 2, wherein the separator (6) comprises a slider (61) and a plate (62) guided by the same slider (61). 4. laser head (1) according to one of claims 1 to 3, further comprising a position sensor (8), and wherein the separator (6) is coupled to the sensor (8) so that the sensor (8) detects the position of the separator (6) during operation of the laser head (1). Laser head (1) according to claim 4, in which the laser source (2) and the position sensor (8) are coupled in such a way that the laser source (2) emits a laser beam only when the separator (6) is in the open position. The laser head (1) according to one of claims 1 to 5, further comprising a differential pressure sensor (9) for measuring the pressure difference between the dry cavity (43) and the flood cavity (44). during operation of the laser head (1). Laser head (1) according to claim 6, wherein the separator (6) is coupled to the differential pressure sensor (9) so that the displacement of the separator (6) between the open position and the position of closure is controlled by measuring the differential pressure between the dry cavity (43) and the flood cavity (44), the separator (6) being held in the closed position as long as the differential pressure sensor (9) indicates a pressure in the dry cavity (43) below a pressure in the flood cavity (44), the separator (6) being moved into the open position when the differential pressure sensor (9) indicates a pressure in the dry cavity ( 43) greater than or equal to the pressure in the flood cavity (44). 8. laser head (1) according to claim 6, further comprising a lever for manually moving the separator (6) between the open position and the closed position. 9. laser head (1) according to one of claims 1 to 8, wherein the switch (7) and separator (6) are coupled so that the switch (7) prevents the passage of gas into the cavity floodable (44) when the separator (6) moves from the open position to the closed position.