Machine for processing tubes and profiles, having a system for scanning the cross-sectional contour of the tubes and profiles being processed

Abstract

A machine for laser machining of tubes and profiles is provided that overcomes the difficulty of focusing an image of the working area of a scanning system. [Solution] A machine for processing tubes and profiles T comprises a processing head 12, a feed device 14 for moving the workpiece along a feed axis x, and a scanning system for scanning the cross-sectional contour of the tube or profile T being processed. The processing head 12 is translatable in a vertical transverse plane perpendicular to the feed axis x. The scanning system comprises at least one laser scanning module 20 having a laser projection unit 22 for projecting a light blade L that irradiates at least a portion of the tube or profile T being processed, and a camera 24 for acquiring an image of the portion of the tube or profile T. The optical axis o2 of the camera 24 is tilted towards the light blade L and moved to a position where the focal plane FP coincides as closely as possible with the plane WP of the light blade L.

Description

[Technical Field]

[0001] The present invention relates generally to machines for processing tubes and profiles, and in particular to machines for laser processing (e.g., laser cutting) of tubes and profiles, equipped with a scanning system for scanning the cross-sectional contours of the tubes and profiles being processed.

[0002] In the following description and in the claims, the terms "tube" and "profile" are used to identify any elongated article of manufacture having a uniform cross-section (except for machining tolerances) along its longitudinal axis, which may be of any contour, whether closed (e.g., circular, rectangular, square, etc.) or open (e.g., L-shaped, C-shaped, U-shaped, etc.). [Background technology]

[0003] With regard to machines for laser machining of tubes and profiles, it is known to use scanning systems to detect the cross-sectional geometry of the tube or profile being machined.

[0004] In particular, a scanning system is known that includes a pair of laser scanning modules (LSMs), each equipped with a laser projection unit capable of projecting a light blade onto the surface of a tube or profile being processed, a camera capable of acquiring an image of a portion of the tube or profile being processed that is illuminated by the light blade emitted by the laser emission unit, and a processing unit capable of processing the images acquired by the camera of each laser scanning module to reconstruct all or at least part of the contour of the cross section of the tube or profile being processed. Using such a scanning system, the actual contour of the cross section of the tube or profile being processed can be known at any time, but this contour may differ more or less significantly from the theoretical contour depending on the machining tolerances. Therefore, for example, it is possible to center the processing operation to be performed based on the actual contour of the cross section of the tube or profile being processed.

[0005] An example of a machine for the laser processing of tubes and profiles, equipped with such a scanning system, is known from EP-A-3233366 in the name of the applicant.

[0006] According to this known solution, the machine comprises a laser processing head adapted to project a focused laser beam onto the surface of the tube or profile to be processed, and a scanning system adapted to scan the cross-sectional contour of the tube or profile being processed, the scanning system comprising at least one laser scanning module having a laser projection unit for projecting a light blade for illuminating the upper part of the tube or profile being processed, and a camera for acquiring an image of that part of the tube or profile illuminated by the light blade. The processing head is mounted so that it can translate in a lateral direction, i.e., in a plane perpendicular to the longitudinal axis of the tube or profile, and preferably also in a vertical direction. The laser scanning module is mounted so that it can be drivingly coupled to the processing head for translational movement at least along the lateral direction.

[0007] Such a scanning system makes it possible to reconstruct the geometry of the cross-sectional contour of tubes or profiles of any shape and size, utilizing lateral translational movement of the laser scanning module and rotational movement of the tube or profile about its longitudinal axis.

[0008] In such a scanning system, the laser projection unit and camera of each laser scanning module are positioned at a certain distance from each other and with a certain angle between the camera's viewing axis and the direction of propagation of the light blade projected by the laser projection unit. The camera's viewing cone, the size of which depends on the camera and its optics, intersects with the plane of the light blade projected by the laser projection unit, thereby defining the working area of the laser scanning module. Because the plane of the light blade is not parallel to the plane of the camera sensor, focusing the entire working area is significantly complicated. In fact, optimal focusing would require an optical system with an infinite depth of field, or at least a depth of field equal to the height of the quadrilateral formed by the intersection of the plane of the light blade with the camera's viewing cone. Therefore, in such a scanning system, the only possible way to increase the depth of field is to close the optical system's aperture, which results in the following two disadvantages: - Closing the aperture reduces the amount of light that can be captured by the optical system, and therefore the exposure time must be increased to obtain a sufficiently bright image. - Closing the aperture too much can cause excessive diffraction of light and reduce image sharpness. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent Application Publication No. 3233366 Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide a machine for processing tubes and profiles, and in particular a machine for laser processing (e.g. laser cutting) of tubes and profiles, which is equipped with a scanning system for scanning the cross-sectional contour of the tube or profile being processed, which overcomes the drawbacks of the prior art discussed above. [Means for solving the problem]

[0011] This and other objects are fully achieved according to the invention by a machine for processing tubes and profiles as defined in the attached independent claim 1.

[0012] Advantageous embodiments of the invention are specified in the dependent claims, the subject matter of which is to be understood as forming an integral part of the following description.

[0013] In general terms, the invention is based on the idea of using, for each laser scanning module of a scanning system of the type specified above, a camera configured so that its optical axis is tilted at an angle relative to the normal to the plane of the camera sensor (i.e., so that the optical plane of the camera lens is tilted at an angle relative to the plane of the camera sensor), and more specifically, so that it is tilted towards the plane in which the optical blade generated by the laser projection part of each laser scanning module lies. In this way, focusing of the image of the working area is improved by the Scheimpflug principle.

[0014] Preferably, the angle at which the optical axis of the camera lens is oblique to a direction perpendicular to the plane of the camera sensor is selected so that the focal plane of the camera lens coincides with the plane of the light blade generated by the laser projection portion of each laser scanning module, thereby optimally focusing the image of the working area.

[0015] It is obvious that using a camera configured in this way is a simple and inexpensive solution to the problem of improving the focusing of an image of a working area. Such a camera can be specially made in each case to have the desired tilt between its optical axis and the direction perpendicular to the sensor plane, or it can be obtained by modifying an existing camera by inserting an adapter between the camera lens and the camera sensor to obtain the desired tilt between these two components of the camera.

[0016] According to one embodiment, the scanning system comprises at least one first laser scanning module and one second laser scanning module arranged on opposite sides of a vertical plane passing through the feed axis of the machine.

[0017] Preferably, the plurality of laser scanning modules are arranged so that the light blades generated by each laser projection unit lie in the same plane, preferably in the above-mentioned vertical plane.

[0018] Further features and advantages of the invention will become apparent from the following detailed description, given solely by way of non-limiting example with reference to the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a partial perspective view of a machine for processing tubes and profiles, in particular a machine for laser cutting of tubes and profiles, according to one embodiment of the invention, equipped with a scanning system for scanning the cross-sectional contour of the tube or profile being processed; FIG. [Figure 2] FIG. 2 is a front view of the machine of FIG. 1. [Figure 3] FIG. 2 is a side view of the machine of FIG. 1. [Figure 4] 2 is a perspective view showing a schematic arrangement of a laser scanning module of the scanning system of the machine of FIG. 1 relative to the tube or profile being processed; FIG. [Figure 5]2 is a front view of the machine of FIG. 1 showing a schematic representation of the positioning of the laser scanning module of the scanning system relative to the tube or profile being processed. [Figure 6] FIG. 2 is a detailed view of one of the two laser scanning modules of the scanning system of the machine of FIG. 1. [Figure 7] FIG. 7 is a diagram of the working principle of the camera of the laser scanning module of FIG. 6; DETAILED DESCRIPTION OF THE INVENTION

[0020] In the following description and claims, the term "longitudinal" is used to identify directions that are coincident with or parallel to the feed axis (or machining axis) of the machine, and the term "transverse" is used to identify directions that lie in a plane perpendicular to the feed axis of the machine.

[0021] Referring first to FIG. 1 , a machine for processing tubes and profiles according to the present invention is generally designated by the reference M. In the example proposed herein, machine M is a machine for cutting, and in particular laser cutting, tubes and profiles, but the present invention is equally applicable to machines adapted to perform other types of processing on tubes and profiles, such as welding operations. Furthermore, while the following description refers to the application of the machine for laser cutting tubes, it will be clear that it can be used for profiles as well. The tubes or profiles that the machine can process can have cross sections of various shapes and sizes, such as round tubes, square tubes, rectangular tubes, C-profiles, T-profiles, IPE profiles, HEA profiles, etc.

[0022] The machine M obviously comprises a base 10, a processing head 12 adapted to perform a processing operation (in this case a cutting operation) on the surface of the tube T by means of a focused laser beam projected by a laser nozzle 18, a feed device 14 adapted to feed the tube T along a feed axis (or processing axis) x along which the longitudinal axis of the tube T being processed is aligned, and a scanning system adapted to scan at least a part (in particular the upper part) of the cross-sectional contour of the tube T. In the illustrated embodiment, the machine M further comprises a guide device 16, which is located upstream of the processing head 12 and is arranged to guide the tube T as it is fed by the feed device 14. However, the guide device 16 may be omitted.

[0023] 2-5, the scanning system includes at least one laser scanning module, which includes a laser projection unit 22 configured to project a light blade L to illuminate a portion of the tube T being processed, and a camera 24 configured to capture an image of the portion of the tube being processed illuminated by the light blade L projected by the laser projection unit 22. Preferably, as in the embodiment illustrated herein, the scanning system includes two laser scanning modules 20 (as can be seen particularly in FIGS. 2 and 5) located on one side and the other side of a vertical plane through which the feed axis x passes, and located above the feed axis x. However, more than two laser scanning modules could be provided.

[0024] The machining head 12 is movable relative to the base 10 in a lateral plane, i.e., a plane perpendicular to the feed axis x (a vertical plane, assuming that the feed axis x is horizontal). In particular, the machining head 12 is movable at least horizontally (denoted by the symbol y in FIGS. 1 and 2, hereinafter also referred to as the lateral direction) within the lateral plane, and preferably both horizontally and vertically (denoted by the symbol z in FIGS. 1 and 2). In this regard, for example, the machining head 12 is carried by a support structure 26, which is mounted on a slide 28 so as to be translatable in the vertical direction z. The slide 28 is mounted so as to be translatable in the lateral direction y. The machining head 12 is therefore movable in the lateral plane with two degrees of freedom, namely, one degree of translation in the vertical direction z and one degree of translation in the lateral direction y. Furthermore, as in the illustrated embodiment, the machining head 12 is preferably (but not necessarily) mounted on the head support structure 26 so that it can tilt about a tilt axis t oriented laterally (or, according to another embodiment not shown, about two mutually perpendicular tilt axes). The machining head 12 may also move in a direction parallel to the feed axis x.

[0025] The feed device 14 is preferably adapted to control not only the translational movement (feed movement) of the tube T along the feed axis x, but also the rotational movement of the tube T about that axis. In the case of a machine for laser cutting of tubes, the combination of the degrees of freedom of movement of the processing head 12 (translation along the lateral direction y and along the vertical direction z, and possibly rotation about the tilt axis t and / or translation along the direction of the feed axis x) with the degrees of freedom of movement of the tube T (translation along the feed axis x and rotation about the feed axis x) makes it possible to perform cuts along any desired cutting line on the wall surface of the tube T.

[0026] The two laser scanning modules 20 are mounted on a support structure 30, which is fixed to the slide 28. The laser scanning modules 20 therefore move together with the slide 28, and therefore also with the processing head 12, along the lateral direction y.

[0027] According to a further embodiment, the support structure on which the laser scanning module is mounted is fixed to the head support structure, or generally to the sled on which the machining head is mounted, so that the laser scanning module is drivingly coupled to translate together with the machining head in both the lateral direction y and the vertical direction z.

[0028] In the illustrated embodiment, the support structure 30 has a generally C-shaped configuration and includes a cross member 32 attached to the slide 28 and a pair of side arms 34 extending longitudinally and attached to opposite ends of the cross member 32. A mounting flange 36 is rigidly connected to the free end of each side arm 34. A similar mounting flange 38 is rigidly connected to one end of a support arm 40 of each laser scanning module 20 (preferably extending in line with each side arm 34 and having the laser projection unit 22 and camera 24 mounted thereon). Thus, each laser scanning module 20 can be easily mounted to the support structure 30 by connecting the mounting flange 38 of each support arm 40 to the mounting flange 36 of each side arm 34, for example by screws.

[0029] 4 and 5, each laser projection unit 22 is adapted to generate a light blade L with a constant aperture angle α, e.g., 20°. Preferably, each laser projection unit 22 is provided with an optical system so that the light is uniformly spread across the entire blade aperture, or at least across most of it, in a self-evident manner. Preferably, each laser projection unit 22 is mounted such that its optical axis (denoted by o1) lies in a horizontal plane. Furthermore, the optical axis o1 of each laser projection unit 22 is inclined at a constant angle β with respect to the horizontal, as shown in FIG. 5. Preferably, the optical axes o1 of the laser projection units 22 of the multiple laser scanning modules 20 lie in the same plane. Even more preferably, the vertical plane in which the optical axis o1 of the laser projection unit 22 of the laser scanning module 20 lies is in the same plane as the optical axis o1 of the laser beam projected by the laser nozzle 18. L When the processing head 12 is configured so that the optical axis o of the laser beam projected by the laser nozzle 18 of the processing head 12 is vertical, LIn this way, the scanning system precisely scans the contour of the tube T at the cross section that is acted upon by the laser beam projected by the laser nozzle 18 of the processing head 12 during processing. This obviously guarantees the highest possible accuracy.

[0030] Each camera 24 is preferably mounted such that its optical axis (denoted o2 in Figures 3 and 4) is in the same plane as the optical axis o1 of the laser projection unit 22 of the same laser scanning module 20 and is inclined relative to the optical axis o1 of the laser projection unit 22 so as to acquire an image of the portion of the surface of the tube T being processed that is illuminated by the light blade L projected by the laser projection unit 22. The cameras 24 are connected by suitable data transmission lines (not shown, but in any case of obvious type) to a processing unit (also not shown, but of obvious type) adapted to process the images acquired by each camera in order to reconstruct the overall contour of the cross section of the tube T being processed, or at least the geometry of a portion thereof.

[0031] 6 and 7, each camera 24 trivially comprises a lens system 42 and a sensor 44, in particular (but not necessarily) a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. The lens system 42 trivially comprises a lens 46 (or, more generally, at least one lens). According to the invention, each camera 24 is configured such that the optical axis o2 of the lens system 42 of the camera 24 is at a certain angle (denoted by the symbol SP) with respect to a direction perpendicular to the sensor plane of the sensor 44.

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[0032] Specifically, as shown in FIG. 7, the angle of inclination between the lens system 42 of the camera 24 and the sensor 44

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[0033] The solution presented here therefore makes it possible to improve the performance of known scanning systems, in particular the scanning systems known from the documents cited in the introductory part of this description, and to ensure optimal focusing of the working area in a simple and inexpensive way.

[0034] The present invention has been described herein with reference to one possible embodiment, and it is to be understood that other embodiments, as defined in the accompanying claims, may be envisioned which share the same inventive core as the embodiment described herein.

Claims

1. A machine for processing tubes and profiles (T), comprising: A processing head (12), a feed device (14) designed to move the tube or profile (T) to be processed along a feed axis (x) towards said processing head (12) each time; a scanning system for scanning the cross-sectional contour of the tube or profile (T) during processing; Equipped with The scanning system comprises at least one laser scanning module (20) having a laser projection unit (22) configured to project a light blade (L) to irradiate at least a portion of the tube or profile (T) being processed, and a camera (24) configured to capture an image of the portion of the tube or profile (T) illuminated by the light blade (L); The camera (24) of the at least one laser scanning module (20) includes a lens system (42) and a sensor (44), and the lens system (42) and the sensor (44) are aligned with an optical axis (o) of the lens system (42). ２ ) is at a constant angle with respect to the direction perpendicular to the sensor plane (SP) of the sensor (44). [Equation 1] and configured to tilt toward the light blade (L) generated by the laser projection unit (22) of the at least one laser scanning module (20). machine.

2. the angle of inclination between the lens system (42) of the camera (24) and the sensor (44); [Equation 2] 2. The machine of claim 1, wherein the angle is such that the focal plane (FP) of the lens system (42) coincides with the plane (WP) of the light blade (L) generated by the laser projection unit (22).

3. The camera (24) of the at least one laser scanning module (20) rotates the lens system (42) at the angle of inclination relative to the sensor (44). [Equation 3] 3. A machine according to claim 1 or 2, comprising an adapter (48) interposed between said lens system (42) and said sensor (44) to tilt said lens system (42) at .

4. 4. The machine according to claim 1, wherein the machining head (12) is mounted so as to be able to translate along a transverse horizontal direction relative to the tube or profile (T) being machined, i.e., a direction perpendicular to the feed axis (x), and the at least one laser scanning module (20) is coupled to the machining head (12) so as to be integral with the machining head (12) in the translational movement along the transverse horizontal direction.

5. 5. A machine according to claim 4, wherein the processing head (12) is mounted so as to be vertically translatable relative to the tube or profile (T).

6. 6. The machine according to claim 5, wherein the at least one laser scanning module (20) is connected to the processing head (12) so as to be integral with the processing head (12) also in the translational movement in the vertical direction.

7. 7. The machine according to claim 1, wherein the scanning system comprises at least one first laser scanning module (20) and one second laser scanning module (20) arranged on opposite sides of a vertical plane passing through the feed axis (x).

8. 8. A machine according to any one of claims 1 to 7, wherein the plurality of laser scanning modules (20) are arranged in such a way that the light blades (L) generated by each of the laser projection units (22) lie in the same plane (WP), in particular in a horizontal vertical plane, i.e., in a plane perpendicular to the feed axis (x).

9. 9. Machine according to any one of the preceding claims, wherein the machining head (12) is configured to project a focused laser beam in order to perform machining operations, in particular cutting operations, on the tube or profile (T).

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