APPARATUS AND PROCESS FOR THE SURFACE PROCESSING OF CYLINDRICAL BODIES, IN PARTICULAR LAMINATION CYLINDERS

Abstract

An apparatus for surface processing of cylindrical bodies including a work station (100) for rotatably supporting the cylindrical body (1), a laser emitter (600) movable along a main direction (X) parallel to the rotation axis (K) of the cylindrical body (1) and according to an auxiliary direction (Z) transverse to the main direction (X), a distance sensor (700) for detecting a control parameter relative to a distance of the sensor or the laser emitter (600), and a control unit (15) configured for commanding a movement of the laser emitter (600) and of the distance sensor (700) along said main direction (X), commanding the emission of a laser beam directed towards a surface of the cylindrical body (1), executing a correction procedure adapted to compensate for the eccentricity of the cylindrical body (1) with respect to said rotation axis (K).

Claims

1. An apparatus for the surface processing of a cylindrical body, the apparatus bodies comprising: a work station defining at least one operative seat arranged to receive, in a use condition of the apparatus, the cylindrical body to be processed, said work station configured to support the cylindrical body to allow the cylindrical body to rotate about a rotation axis (K), at least one laser emitter cooperating with the work station and configured to emit at least one laser beam in a direction of said operative seat, said laser emitter movable at least along a main direction (X) substantially parallel to the rotation axis (K) of the cylindrical body and according to an auxiliary direction (Z) transverse to said main direction (X), at least one distance sensor arranged in a predetermined positional relationship with respect to the laser emitter and configured to detect a control parameter relative to a distance of the sensor or of the laser emitter from an external lateral surface of the cylindrical body positioned in the operative seat and emitting a corresponding detection signal, a control unit communicatively connected with the laser emitter and with the distance sensor, wherein said control unit is configured to: command a movement of the laser emitter and of the distance sensor along said main direction (X), command, at least during a predetermined travel along said main direction (X) of the laser emitter, the emission of a laser beam directed towards a surface of the cylindrical body rotating in the operative seat to process the surface of the cylindrical body, and execute a correction procedure comprising: receiving one or more detection signals from the distance sensor, each of the detection signals being relative to a respective angular position taken by the cylindrical body in said operative seat, based on said one or more detection signals, determining corresponding distance values of the distance sensor or of the laser emitter from the surface of the cylindrical body rotating in said operative seat, determining if said distance values meet a pre-established acceptability criterion, and if one or more of said distance values do not meet the predetermined acceptability criterion, correcting at least one position of the laser emitter along the auxiliary direction (Z).

2. The apparatus according to claim 1, wherein said receiving step includes receiving one or more, of said at least one detection signals from the distance sensor for each complete rotation of the cylindrical body around said rotation axis (K); or wherein said step of determining the distance values includes determining, for each complete rotation of the cylindrical body around said rotation axis (K), a respective distance value for each of the angular positions taken by the cylindrical body.

3. The apparatus according to claim 1, wherein said receiving step includes receiving a plurality of the detection signals from the distance sensor for each complete rotation of the cylindrical body around said rotation axis (K) relative to a same section of the cylindrical body, and wherein said step of determining the distance values includes determining, for each complete rotation of the cylindrical body around said rotation axis (K), a plurality of the distance values relative to the same section of the cylindrical body, or wherein the apparatus comprises at least one angular position detector communicatively connected with the control unit and configured for emitting one or more position signals relative to the angular position of the cylindrical body rotating in the operative seat and signal to the control unit an angular position of the cylindrical body in a continuous manner and in real time.

4. The apparatus according to claim 1, wherein said step of receiving one or more of said detection signals from the distance sensor comprises: interrogating said distance sensor to receive corresponding detection signals relative to pre-established angular positions of the cylindrical body; wherein said control unit is configured to interrogate a plurality of times, the distance sensor for each complete rotation of the cylindrical body and then receive a plurality of corresponding the detection signals relative to a respective plurality of pre-established angular positions taken by the cylindrical body at each rotation.

5. The apparatus according to claim 1, wherein said control unit is configured to: determine a plurality of distance values for each complete rotation of the cylindrical body around the rotation axis (K), each of the distance values being relative to a respective of the or of pre-established angular positions taken by the cylindrical body during each complete rotation of the cylindrical body around the rotation axis (K), and store, in a corresponding vector (V), the distance values determined for a same complete rotation of the cylindrical body around the rotation axis (K).

6. The apparatus according to claim 1, wherein said control unit is configured to cyclically repeat said correction procedure, at: (i) regular steps along the main direction (X) or (ii) at pre-established angular positions reached by the laser emitter or by the distance sensor along the main direction (X); and wherein said control unit is configured to command the movement of the laser emitter and of the distance sensor in a plurality of successive positions along said main direction (X) and to repeat said correction procedure at a multiplicity of successive positions taken by the emitter and/or by the distance sensor along said main direction (X).

7. The apparatus according to claim 5, wherein said control unit is configured to: determine a plurality of said vectors, wherein each of the vectors comprises the plurality of distance values determined for a respective complete rotation of the cylindrical body around the rotation axis (K), form a matrix (M) comprising said plurality of said vectors; wherein each of the vectors of said matrix (M) comprises a plurality of the distance values determined for a respective complete rotation of the cylindrical body around the rotation axis (K) and relative to a respective section of the cylindrical body.

8. The apparatus according to claim 7, wherein the matrix (M) comprises a plurality of vectors relative to axially consecutive helices of the cylindrical body, wherein the matrix (M) comprises a plurality of vectors relative to the same section of the cylindrical body.

9. The apparatus according to claim 7, wherein said control unit is configured to: position said distance sensor at a pre-established starting position along the main direction (X), maintain said distance sensor in said starting position during the completion of a plurality of complete rotations of the cylindrical body around the rotation axis (K), determine a plurality of initial vectors (V), wherein each initial vector (V) comprises the plurality of distance values determined for a respective complete rotation of the cylindrical body around the rotation axis (K), said initial vectors all being relative to the same section of the cylindrical body corresponding to said starting position, and form the matrix (M) as matrix comprising said plurality of said initial vectors (V) relative to the same section of the cylindrical body corresponding to said starting position, wherein the control unit is configured to command for commanding the laser emitter to not emit any laser beam directed towards a surface of the cylindrical body rotating in the operative seat until said distance sensor is in said starting position.

10. The apparatus according to claim 9, wherein the control unit is configured to: command the movement of the laser emitter along said pre-established travel, determine updating vectors (V) during the movement of the laser emitter, wherein each of the updating vectors (V) comprises the plurality of distance values determined for a respective complete rotation of the cylindrical body around the rotation axis (K), said updating vectors (V) is relative to axially consecutive helices of the cylindrical body intercepted by the distance sensor during the movement of the laser emitter, and update said matrix (M) by progressively substituting the initial vector (V) that has been present in the matrix (M) for more time as soon as an updating vector (V) is available.

11. The apparatus according to claim 1, wherein said step of determining if said distance values meet a pre-established acceptability criterion includes checking if one or more of the distance values relative to a pre-established number of complete rotations of the cylindrical body fall within a pre-established acceptability range between a minimum distance value and a maximum distance value from the lateral surface of the cylindrical body.

12. The apparatus according to claim 7, wherein said step of determining if said distance values meet a pre-established acceptability criterion comprises: calculating a plurality of normalized distance values, each of the normalized distance values is a function of the distance values, present in said matrix (M), relative to the same rotation angle of the cylindrical body and pertaining to separate rotations of the cylindrical body around the rotation axis (K), and checking if one or more of the normalized distance values fall within a pre-established acceptability range between a minimum distance value and a maximum distance value from the lateral surface of the cylindrical body; wherein each of the normalized distance value is as mean of at least 80% of the distance values, present in said matrix (M), relative to the same rotation angle of the cylindrical body.

13. The apparatus according to claim 11, wherein the control unit is configured to: receive or load, from a memory connected with the control unit, a desired distance value (Hx) between the laser emitter and the lateral surface of the cylindrical body which is maintained during the movement of the laser emitter along said main direction (X), and determine the maximum distance value as a desired distance value (Hx) plus a first tolerance (hi), and the minimum distance value as desired distance value (Hx) minus a second tolerance (h2), and wherein said desired distance value (Hx) between the laser emitter and the lateral surface of the cylindrical body is a constant value along said main direction (X) or a variable value according to a pre-established variability law along said main direction (X).

14. The apparatus according to claim 12, wherein the step of correcting at least one position of the laser emitter along the auxiliary direction (Z) comprises moving the laser emitter closer to the lateral surface of the cylindrical body if, following said step of determining if said distance values meet a pre-established acceptability criterion, one or more of the distance values or one or more of the normalized distance values are greater than a maximum distance value; or wherein the step of correcting at least one position of the laser emitter along the auxiliary direction (Z) comprises moving the laser emitter away from the lateral surface of the cylindrical body if, following said step of determining if said distance values meet a pre-established acceptability criterion, the one or more of the distance values or the one or more of the normalized distance values are lower than the minimum distance value.

15. The apparatus according to claim 1, further comprising at least one guide adjacent to the work station and extended along said main direction (X), at least one conveying support translatable along said guide, and at least one command member active on the conveying support, commanded by said control unit and configured to move the conveying support on said guide along the main direction (X); wherein the distance sensor and/or the laser emitter are carried by the conveying support, and wherein the distance sensor is adjacent at a pre-established distance from the laser emitter.

16. The apparatus according to claim 1, wherein said step of correcting comprises modifying at least one position of the laser emitter along the auxiliary direction (Z), in a manner so as to approach the acceptability criterion, or bring back within the acceptability criterion the distance value or values which do not meet the same acceptability criterion.

17. The apparatus according to claim 15, wherein said laser emitter is carried by the conveying support upon interposition of an intermediate body movable relative to the conveying support at least along said auxiliary direction (Z); or wherein the distance sensor and the laser emitter are both carried by the conveying support upon interposition of an intermediate body movable relative to the conveying support at least along said auxiliary direction (Z); and wherein the apparatus further comprises an adjustment member active at least on the intermediate body and configured to move the intermediate body along the auxiliary direction (Z).

18. The apparatus according to claim 15, wherein the control unit is communicatively connected with the command member and wherein the step of commanding a movement of the laser emitter and of the distance sensor along said main direction (X) is executed by the control unit commanding said command member, and/or wherein the control unit is communicatively connected with the adjustment member, and wherein the step of correcting at least one position of the laser emitter along the auxiliary direction (Z) is executed by the control unit commanding said adjustment member.

19. The apparatus according to claim 1, wherein the work station comprises at least one motor member configured for rotating the cylindrical body received in said operative seat, said motor member being communicatively connected with the control unit which is also configured for commanding the motor member and rotating the cylindrical body around said rotation axis during the execution of said correction procedure; and wherein the control unit is also configured to: receive an input command indicative of an angular speed at which the cylindrical body is rotated during the surface processing of the cylindrical body, and commanding the motor member to set said angular speed for the cylindrical body.

20. A method for surface texturing a rotating cylindrical body, the method comprising: rotating the cylindrical body about a rotation axis while the cylindrical body is supported by a work station; moving a laser emitter and a distance sensor along a main direction parallel to the rotation axis, emitting a laser beam from the laser emitter towards a surface of the cylindrical body to apply a texture to the surface, and executing a correction procedure comprising: receiving detection signals from the distance sensor, wherein each of the detection signals corresponding to an angular position of the cylindrical body, determining distance values indicative of a distance of the sensor or of the laser emitter from the surface of the cylindrical body, and correlating each of the distance values to a corresponding detection signal; determining if each of said distance values meet a pre-established acceptability criterion, for said distance values that do not meet the predetermined acceptability criterion, correcting at least one position of the laser emitter along an auxiliary direction transverse to the main direction.

Description

DETAILED DESCRIPTION

[0116] Further characteristics of the invention will be clearer from the following detailed description. Such description will be made with reference to the enclosed drawings provided only as a non-limiting example, in which:

[0117] FIG. 1 represents a schematic view of a rolling cylinder and relative support system;

[0118] FIG. 2 is a top schematic view of one embodiment of a surface processing apparatus according to aspects of the invention;

[0119] FIG. 3 shows a detail relative to the laser emitter and to the distance sensor used in the apparatus of FIG. 2;

[0120] FIGS. 4 to 6 are schematic views of the apparatus of FIG. 1 in successive operating steps;

[0121] FIGS. 7 and 8 show the section of the cylindrical body being processed perpendicular to the line joining the centers and lying in two different planes. The figures also show the relative trajectory of the laser emitter with respect to the considered sections, as well as the distance Dxy between head and surface at a specific rotation angle;

[0122] FIGS. 7A and 8A are a Cartesian representation of the distances Dxy pursuant to FIGS. 7 and 8, with the variation of the angle where the cylindrical body is situated;

[0123] FIG. 9 is a Cartesian representation which shows a possible progression of an acceptability range for the distance between the laser head and the surface of the cylinder being processed; the acceptability range in the embodiment of FIG. 9 varies along a main direction X parallel to the axis of the cylinder, however such range could be constant along the entire longitudinal extension of the cylinder being processed;

[0124] FIG. 10 is a Cartesian representation in which, in relation to a predetermined section of the cylindrical body, the values of the distance between the laser emitter and the lateral surface of the cylindrical body are represented with the variation of the angle where the cylindrical body itself is situated; on such values, the acceptability range for said values has been superimposed, expressed as upper limit (H+h1) and lower limit (H−h2) with respect to an ideal value H; and

[0125] FIG. 11 is a flow diagram relative to a surface processing according to aspects of the invention, e.g. executable by the apparatus of FIG. 2.

DEFINITIONS AND CONVENTIONS

[0126] In the present detailed description, the corresponding parts illustrated in the various figures are indicated with the same reference numbers. The figures could illustrate the object of the invention by means of representations that are not in scale; therefore, parts and components illustrated in the figures relative to the object of the invention might only regard schematic representations.

[0127] In the present document, the following terms have the meaning indicated hereinbelow: [0128] texturing=processing of a smooth and uniform surface, by making close-together, minute incisions therein; [0129] laser texturing=is a processing of a smooth and uniform surface in which the close-together, minute incisions are made due to the use of one or more laser emitters; [0130] communicatively connected=with reference to a control unit with respect to another component, for expressing a wired or wireless connection that allows the control unit to communicate with the other component by sending commands and/or receiving signals; [0131] vector=it is intended a logic vector containing a plurality of uniform data correlated with each other and logically organized, independent of how such data is then physically stored in a memory; [0132] matrix=it is intended a logic matrix comprising a series of said vectors logically organized so as to form a two-dimensional array of ordered data, independent of how such data is then physically stored in a memory.

DETAILED DESCRIPTION

[0133] With reference to the enclosed figures, reference number 10 indicates an apparatus for the surface processing of a cylindrical body 1. In particular, the apparatus 10 is for example configured for carrying out the texturing of a rolling cylinder.

[0134] The apparatus 10 comprises a work station 100 defining at least one operative seat arranged to receive, in a use condition of the apparatus 10, a cylindrical body 1, for example a rolling cylinder, to be superficially processed.

[0135] The work station 100 comprises in particular a base 101 on which lateral supports 102 are for example positioned, which in turn support suitable supports 200 that engage axially opposite terminal portions of the cylindrical body 1 being processed. The supports are configured such that the cylindrical body 1 is rotatably sustained in the operative seat and can thus rotate according to a predetermined rotation axis K. For example, each of the supports 200 can comprise a respective conical body cooperating with a corresponding conical recess 5 made on one of the two head surfaces 1a of the ends of the cylindrical body 1 (FIG. 2). Naturally, supports of different nature can be provided, for example by using bearings or other elements. Due to the described coupling, the rotation axis K is preferably extended in the horizontal direction, as is visible in the enclosed figures, and substantially coincides with the axis of axial symmetry of the cylindrical body 1. In reality, the rotation axis K is generally not perfectly coinciding with the axis of symmetry of the cylindrical body 1: moreover, this circumstance can become more considerable in the course of the repeated grinding and texturing processing operations, causing an eccentricity between the lateral surface 2 of the cylinder being processed and the rotation axis K. The work station 100 also comprises at least one motor member 300 configured for rotating the cylindrical body 1 at a desired angular speed, fixed or settable depending on the type of processing. The apparatus 10 comprises at least one laser emitter 600 cooperating with the work station 100 and configured for emitting at least one laser beam in the direction of said operative seat. The laser emitter 600 comprises for example a high-power laser or another laser capable of making micro-incisions on a steel surface such as that of the rolling cylinders. Of course, depending on the type of incision to be made and on the type of surface to be processed, other laser types could be used, for example: single-mode continuous fiber laser; single-mode pulsed fiber laser, CO2 laser and any other laser type adapted to achieve the present incision processing. It should be observed that, without at all limiting the present invention, the apparatus 10 can comprise a plurality of laser emitters, each for example responsible for carrying out a respective surface processing of a corresponding area of competence of the surface of the cylindrical body 1 and each operating as described hereinbelow. Each laser emitter 600 is coupled to at least one distance sensor 700 arranged in a predetermined positional relationship with respect to the laser emitter 600: as detailed hereinbelow, the laser emitter 600 and the sensor can be carried by a same support and thus be constantly situated in the same relative position with respect to each other. Generally, the distance A between these two components (FIG. 3) measured along the axis of the cylinder being processed is on the order of a few tens of millimeters, for example 50 mm, or 70 mm, or similar values. Alternatively, distance sensor 700 and laser emitter 600 can be carried by respective supports which in any case will be driven so as to maintain a positional relationship with each other.

[0136] The distance sensor 700 is configured for detecting a control parameter relative to a distance of the sensor itself or of the laser emitter 600 from a lateral surface 2 of the cylindrical body 1 placed rotating in the operative seat. The distance sensor 700 is preferably of laser type; alternatively, inductive, capacitive or ultrasound distance sensors can be used, or distance sensors of another type can be used, in any case capable of detecting a parameter relative to the distance of the sensor or of the emitter from the surface of the body being processed. For example, the sensor can comprise an emitter/receiver of signals and hence detect the delay or the phase shift between the emitted signal and the signal reflected by the cylindrical body 1 and emitting a corresponding detection signal tied to the distance between the sensor itself and the lateral surface of the cylindrical body 1 being processed.

[0137] As is visible in the enclosed figures, the apparatus 10 also comprises a guide 800 adjacent to the work station 100, and for example constituting part of the latter, and extended along said main direction X: the guide 800 is arranged parallel to the axis K of the cylinder at least for the entire axial extension of the operative seat and hence of the cylinder being processed. A conveying support 400, for example a carriage or a slide or a movable plate, is mounted on the guide 800 so as to translate along the guide 800 itself. A command member, schematically represented by the block 401 in FIG. 3 and for example a hydraulic, electric or pneumatic actuator, or an actuator of another type, is active on the conveying support 400 in order to move the conveying support 400 on the guide 800 along the main direction X. In an optional solution, the command member 401 provides for at least one linear electric motor: nevertheless, as mentioned above, other types of actuators can be used such as, for example the commands with motors and ball recirculation screws as long as they ensure high precision of the movements and high speed of the commands set by the control unit 15, as will be better described hereinbelow. The distance sensor 700 and the laser emitter 600 are both carried by the conveying support 400 and, optionally, the distance sensor 700 is placed adjacent at a predetermined (and preferably reduced) distance from the laser emitter 600. Alternatively, the distance sensor 700 can be at a certain distance from the emitter, but in such case it will be necessary to account for the distance between these two components in the correction of the distance described hereinbelow. It should be observed that in one variant, the sensor 700 and the laser emitter 600 could be mounted on respective conveyor supports 400 controlled so as to translate on said guide 800 or on guides parallel to the main direction X: in such case, however, the movement of the supports will have to be suitably synchronized so as to maintain distance sensor 700 and relative laser emitter 600 in a known positional relationship.

[0138] In the embodiment illustrated in the enclosed FIGS. 2-6, the distance sensor 700 is placed adjacent to the laser emitter 600. Preferably, the distance sensor 700 is placed in close vicinity to the laser emitter, alongside the laser emitter on the side of the movement sense of the main support along the main direction X.

[0139] It should also be observed that both the laser emitter 600 and the sensor 700 are carried by the conveying support 400 upon interposition of an intermediate body 500, in turn that is movable relative to the conveying support 400 at least along an auxiliary direction Z which is directed transverse to the main direction X, in particular perpendicular to the main direction X, such that a movement of the intermediate body 500 causing a radial moving away or approaching of the distance sensor 700 and of the emitter 600 with respect to the lateral surface 2 of the cylindrical body 1 being processed. In the alternative in which the distance sensor 700 and the emitter are mounted on respective conveyor supports, then between distance sensor 700 and respective conveying support 400 and between laser emitter 600 and respective conveying support 400, a respective intermediate body 500 would be provided for. Each intermediate body 500 would in such case be coupled to the respective conveying support 400 in a movable manner along an auxiliary direction Z directed transverse to the main direction X and in particular perpendicular to the main direction X.

[0140] In order to allow the relative movement between conveying support 400 and intermediate body 500 along the auxiliary direction Z, the apparatus 10 comprises an adjustment member, identified as schematic block 501 in FIG. 2, active at least on the intermediate body 500, optionally interposed between the intermediate body 500 and the conveying support 400, and configured for moving the intermediate body 500 relative to the respective support along the auxiliary direction Z.

[0141] The apparatus 10 comprises, as already mentioned above, the control unit 15 which is connected with the distance sensor 700, with the laser emitter 600, with the motor member 300, with the command member 401 and with the adjustment member 501 described above in order to coordinate and control the actions thereof in a manner so as to effectively carry out the surface processing of the cylindrical body 1. In particular, the control unit 15 is configured for commanding the motor member 300 and rotating the cylindrical body 1 around its rotation axis K during the execution of said correction procedure. The control unit 15 is also communicatively connected with the command member 401 for commanding the movement of the laser emitter 600 and of the distance sensor 700 along the main direction X. The control unit 15 is also communicatively connected with the adjustment member 501 in order to correct the position of the laser emitter 600 and of the distance sensor 700 along the auxiliary direction Z. Finally, the control unit 15 is set to command the laser emitter 600 in order to cause, at least during a predetermined travel along said main direction X of the laser emitter 600, the emission of a laser beam directed towards a surface of the cylindrical body 1 rotating in the operative seat, consequently allowing a surface processing of the cylindrical body 1 itself.

[0142] In further detail, and in accordance with aspects of the present invention, the control unit 15, in addition to commanding the movement of the laser emitter 600 and of the distance sensor 700 along said main direction X and the emission of a laser beam directed towards a surface of the cylindrical body 1 rotating in the operative seat, is also configured for executing a correction procedure aimed to compensate for any possible eccentricity between the lateral surface 2 of the cylindrical body 1 and the rotation axis K.

[0143] In particular, the correction procedure executed by the control unit 15 during the processing comprising the following steps: [0144] receiving a plurality of detection signals from the distance sensor 700, [0145] on the basis of the detection signals, determining corresponding distance values of the sensor or of the laser emitter 600 from the lateral surface 2 of the cylindrical body 1, [0146] then evaluating if said distance values meet or do not meet a predetermined acceptability criterion, and [0147] if one or more of the distance values does not meet the predetermined acceptability criterion, correcting at least one position of the laser emitter 600 along the auxiliary direction Z, for example by actuating the adjustment member 501 and determining a suitable adjustment of the position of the emitter in auxiliary direction Z aimed to compensate for an excessive eccentricity.

[0148] In practice, each detection signal coming from the distance sensor 700 relates to a respective angular position taken by the cylindrical body 1 in said operative seat, and hence the control unit 15, by acquiring a plurality of detection signals relative to different angular positions of the cylindrical body 1, is capable of understanding if the section of the cylindrical body 1 under examination shows or does not show an excessive eccentricity with respect to the rotation axis K.

[0149] In accordance with a further aspect, the control unit 15, in the step of receiving the detection signals from the distance sensor 700, is configured for receiving a plurality of detection signals from the distance sensor 700 for each complete rotation of the cylindrical body 1 around said rotation axis K and hence determining, for each complete rotation of the cylindrical body 1 around said rotation axis K, a respective distance value for each of the predetermined angular positions taken by the cylindrical body 1. In particular, the control unit 15 can be configured for acquiring a respective distance value for each detection signal emitted by the distance sensor 700 and relative to each of a plurality of predetermined angular positions taken on during a same complete rotation of the cylindrical body itself.

[0150] In this manner, for each rotation, the control unit 15 acquires a plurality of distance values and hence can determine, with extreme accuracy, the possible presence of eccentricity and carry out the necessary correction operations by acting on the adjustment member 501 in real time during the movement of the laser emitter 600 and of the distance sensor 700 along the main direction X.

[0151] In more detail, it should be observed that the apparatus 10 can comprise an angular position detector, optionally comprising at least one encoder for example fit on the rotation axis of the cylindrical body 1 and capable of recognizing the angular position of the cylindrical body itself. The angular position detector is also communicatively connected with the control unit 15 which, at predetermined angular positions (α.sub.1, α.sub.2, . . . α.sub.n) of the cylindrical body 1 rotating in the operative seat, records the distance value between the sensor 700 and the cylindrical shell 1. Alternatively, an angular position detector can be provided which emits a corresponding signal upon reaching the predetermined angular positions, with the control unit configured for receiving the position signals from the angular position detector, optionally also determining the angular position of the cylindrical body 1 on the basis of the position signals, and for interrogating the distance sensor 700 upon receiving each (or a predetermined number) of the angular position signals.

[0152] In each case, the control unit 15 samples and receives detection signals of the distance, each corresponding to a predetermined angular position of the angular positions (α.sub.1, α.sub.2, . . . α.sub.n) taken by the cylindrical body 1, which are optionally angularly equidistant from each other; in this manner, the control unit 15 can for example sample the distance detection signals every 90° or every 60° or every 45° or every 30° or every 15° (of course samplings that are even closer together can also be provided) of rotation of the cylindrical body 1, consequently involving the sampling frequency of the distance detection signal.

[0153] In practice, the control unit 15 can be configured for interrogating, a plurality of times, the distance sensor 700 for each complete rotation of the cylindrical body 1 (for example at least 4 or at least 8 or at least 16 or multiple times per revolution) and in order to therefore receive a plurality of corresponding detection signals, each relative to a respective plurality of predetermined angular positions (α.sub.1, α.sub.2, . . . α.sub.n) taken by the cylindrical body 1 at each rotation.

[0154] Therefore, the control unit 15 can determine a plurality of distance values (of the distance sensor 700 and hence of the emitter 600 adjacent thereto) for each complete rotation of the cylindrical body 1 around the rotation axis K, where each distance value relates to a respective angular position of the angular positions (α.sub.1, α.sub.2, . . . α.sub.n) taken by the cylindrical body 1 during each complete rotation of the cylindrical body 1 around the rotation axis K.

[0155] Once the distance values relative to one or more complete revolutions of the cylindrical body 1 are available, the control unit 15 can determine if such distance values meet or do not meet the predetermined acceptability criterion mentioned above, hence establishing if there is an excessive eccentricity or not. For example, the control unit 15 can be configured for checking if one or more distance values relative to a predetermined number of complete rotations of the cylindrical body 1, optionally relative to a same complete rotation of the cylindrical body 1, around the rotation axis K, fall within a pre-established acceptability range comprised between a minimum distance value and a maximum distance value from the lateral surface 2 of the cylindrical body 1. If, following such verification, the control unit 15 establishes that, for one or more angular positions of the cylindrical body 1, the measured distance falls outside the acceptability range, the control unit 15 can consequently command the movement of the distance sensor 700 and above all of the laser emitter 600 according to the auxiliary direction Z, in a manner so as to bring back all the distances within the acceptability range.

[0156] In accordance with a further aspect, the control unit 15 is configured for storing the distance values relative to a same rotation of the cylindrical body 1 in a corresponding vector V.

[0157] In accordance with a further aspect, the control unit 15 determines a plurality of said vectors and forms a matrix M comprising said plurality of the abovementioned vectors: each vector V comprises the plurality of distance values determined for a respective complete rotation of the cylindrical body 1 around the rotation axis K.

[0158] In more detail, in an initial step the sensor and the laser emitter 600 are not moved along the main direction X and the control unit 15 provides to collect, multiple times and cyclically, the distance values determined for a same section of the cylindrical body 1 and relative to the same complete rotation of the cylindrical body 1 around the rotation axis K, thus creating an initial matrix M with m vectors V relative to the same section of the cylindrical body 1.

[0159] In other words, the distance samples acquired at the angles α.sub.1, α.sub.2, . . . α.sub.n, are stored in a respective numeric vector V for each complete revolution of the cylindrical body 1. When the cylindrical body 1 has complete a complete rotation, the acquisition continues, on the same section of the cylinder (hence with emitter and sensor stopped), storing other distance data (at the same angles α.sub.1, α.sub.2, . . . α.sub.n) in a successive vector V. In this manner, a matrix M of the distances is constructed, containing data relative to a same section of the cylinder, where the measurements are repeated “m” times. Each of the m columns of the matrix M represents a vector containing ‘n’ distance measurements.

TABLE-US-00001 V1 V2 . . . Vm α.sub.1 D11 D12 D1m α.sub.2 D21 D22 D2m . . . α.sub.n Dn1 Dn2 Dnm Initial matrix M of the distances

[0160] Hence, D.sub.nm will be the distance detected by the distance sensor 700 at the angle α.sub.n at the m-th revolution of the cylindrical body 1.

[0161] Then, the texturing processing starts; therefore the laser emitter 600 is activated and the emitter itself and the distance sensor 700 are moved along the main direction X. The control unit 15 then constructs mew vectors V, no longer relative to the same section, but to axially consecutive helices (such being the trajectories both of the impression of the laser beam emitted by the emitter and of the signal emitted by the sensor following the rotary movement of the cylindrical body 1 and of the movement along the main direction X of the sensor and of the emitter) of the cylindrical body 1 which come to progressively modify and update the initial matrix M.

[0162] In an initial step, therefore, the matrix M will only comprise vectors with distance values determined for a respective complete rotation of the cylindrical body 1 around the rotation axis K and all relative to only one section (for example end section) of the cylindrical body 1. Subsequently, the matrix M will be updated with each revolution of the cylinder and a new vector V will be added thereto on the right side, while the first vector V on the left side will be canceled. In this manner, the matrix M preserves its dimensions and new data is updated as the processing progresses. At a certain point, after a predetermined number of rotations of the cylindrical body 1, the matrix M will only comprise a plurality of vectors relative to axially consecutive helices of the cylindrical body 1.

[0163] In order to better illustrate that stated above, reference is made to FIGS. 4-6. Initially, the control unit 15 commands the conveyor member 400, and hence the distance sensor 700, to be moved from a rest position to a starting position (indicated with 1002 in FIG. 6). The control unit 15 maintains the distance sensor 700 in the starting position during the completion of a plurality of complete rotations of the cylindrical body 1 around the rotation axis K and then constructs the initial matrix M as follows. Initial vectors are determined, in which each initial vector V comprises the plurality of distance values determined for a respective complete rotation of the cylindrical body 1 around the rotation axis K: the initial vectors are all relative to the same section of the cylindrical body 1 corresponding to the starting position. The initial matrix M is formed, which comprises the abovementioned initial vectors relative to the same section of the cylindrical body 1 corresponding to said starting position.

[0164] In this step, i.e. until the distance sensor 700 is in starting position, the control unit 15 is configured for commanding the laser emitter 600 to not emit any laser beam directed towards the surface of the cylindrical body 1. After a certain number of revolutions ‘m’, the control unit 15 has then constructed the initial matrix M (reported above in tubular form, as an example) of ‘m×n’ elements comprising ‘m’ vectors V, each having ‘n’ distance values, detected on a same section.

[0165] At this point, the control unit 15 can command the movement of the laser emitter 600 and of the distance sensor 700 along the main axis, also activating the emission of the laser beam by the emitter which will then make a processing on the surface of the cylindrical body 1, following a helical trajectory given by the combination of the rotary motion of the cylindrical body 1 around the axis K and of the translational motion of the emitter along the trajectory X; during such movement, the control unit 15 determines a plurality of updating vectors: each updating vector V comprises the plurality of distance values determined for a respective complete rotation of the cylindrical body 1 around the rotation axis K. Different from the initial vectors, the updating vectors are relative to axially consecutive helices of the cylindrical body 1 intercepted by the distance sensor 700 during the movement of the laser emitter 600 and of the same sensor along the direction X. The control unit 15 then provides for updating the matrix M, progressively substituting the initial vectors with updating vectors; in particular, the control unit 15 provides for substituting, each time an updating vector V is available, the initial vector V that has been present in the matrix M for more time. In summary: the control unit 15 can update the matrix M and consequently the vector V with each revolution, or with each ‘k’ revolutions, of the cylindrical body 1. Such updating occurs by discarding the oldest vector (m=1) contained in the matrix M, and introducing a new vector (m+1th). As stated above, the new column to be added to the matrix M of the distances can be acquired with each revolution of the cylinder, thus obtaining a matrix M whose columns are referred to pitches of the helix that are adjacent to each other; however, considering that the pitch of the helix is generally very small, it is preferable to acquire the new vector V with lower frequency, allowing several (k) revolutions of the cylinder to pass between one acquisition and the next, so as to suitably space apart the samples themselves along the surface of the cylinder.

[0166] The matrix M as constructed above serves for checking if the surface of the cylindrical body 1 is actually (section by section or helix by helix) eccentric with respect to the rotation axis. Due to the creation of the matrix M, and in accordance with a further aspect, the control unit 15 constructs an acceptability criterion which is not affected by possible errors of point reading of the distance, nor by possible localized irregularities of the surface of the cylindrical body 1 (for example due to the presence of undesired particles adhered to the surface itself).

[0167] In particular, once the matrix M is calculated at a certain section or helix of the cylindrical body 1, the step of determining if the distance values meet a predetermined acceptability criterion provides for determining first of all an entire plurality of normalized distance values: each normalized distance value is a function of the distance values, present in matrix M, relative to the same rotation angle of the cylindrical body 1 and pertaining to distinct rotations of the cylindrical body 1 around the rotation axis (K). In particular, each normalized distance value is the mean of the distance values present in the matrix M and relative to the same rotation angle of the cylindrical body 1. For example, each normalized distance value is the mean of at least 80% of the distance values (the control unit 15 can for example be configured for discarding the maximum and minimum values or clearly incorrect values) present in said matrix M, relative to the same rotation angle of the cylindrical body 1,

[0168] In other words, the control unit 15 is configured for executing a processing of the lines 1, 2, . . . n, of the matrix M, determining a normalized vector V, in which the element corresponding to the angle α.sub.n, is given by the mean of the values D.sub.n1, D.sub.n2, . . . D.sub.nm detected by the distance sensor 700 and present in the matrix M: the algorithm calculates the mean of the m distance measurements carried out at the alpha i-th angle:

TABLE-US-00002 normalized V α.sub.1 D1v = 1/m Σ.sub.i=1.sup.m D1i α.sub.2 D2v = 1/m Σ.sub.i=1.sup.m D2i . . . α.sub.n Dnv = 1/m Σ.sub.i=1.sup.m Dni Normalized Vector V

[0169] The normalized vector V then provides, at a certain section or helix in which the control is carried out, the values to be used for each angle so as to check if the distances thus calculated meet the acceptability criterion. Due to the normalized vector V, one avoids that the measurement is effected by localized effects, as discussed above.

[0170] The control unit 15, once the normalized vector V is determined, is also configured for checking if one or more normalized distance values fall within a pre-established acceptability range comprised between a minimum distance value and a maximum distance value from the lateral surface 2 of the cylindrical body 1. Alternatively, for the verification the control unit 15 can use the vector V relative to the latter rotation, giving up however the benefits of the normalized vector V. FIGS. 7 and 7A show the distances D.sub.11, . . . D.sub.n1 of the vector V (e.g. normalized) relative to a first section or helix of the cylindrical body 1 (pitch 1), while FIGS. 8 and 8A show the distances D.sub.1m, . . . D.sub.nm of the vector V (e.g. normalized) relative to an m-th section or helix of the cylindrical body 1 (pitch m).

[0171] The acceptability criterion for the distance measurements can be configured as follows. The control unit 15 can receive or load, from a memory connected with the control unit 15, a desired distance value Hx between the laser emitter 600 and the lateral surface 2 of the cylindrical body 1 which must always be maintained constant during the movement of the laser emitter, in particular along its travel in the main direction X. The control unit 15 then determines the maximum distance value deemed acceptable as sum between the desired distance value Hx and a first tolerance h1. Analogously, the control unit 15 can determine the minimum distance value as difference between the desired distance value Hx and a second tolerance h2. It is observed that, optionally, the value of the first tolerance h1 and of the second tolerance h2 can be equal, thus defining a symmetric acceptability range around the value Hx (FIG. 9). In turn, the desired distance value Hx between the laser emitter 600 and the lateral surface 2 of the cylindrical body 1 can be a constant value along the main direction X or a variable value according to a predetermined variability law along said main direction X (FIG. 9). The variation of the distance H involves a variation of the work point of the laser emitted by the emitter, i.e. of the focusing conditions and hence of the characteristics of its impression on the surface of the cylindrical body 1, and in particular a variation of the distribution of the optical power density at the impression. This phenomenon can be exploited in order to vary the characteristics of the texturing along the axis of the cylindrical body 1 being processed, for example in order to account for the different pressures that will be present during the operation in the rolling mill on the surface of the cylindrical body 1: for example, it may be suitable to obtain a texturing with specific characteristics for the zones of the cylindrical body 1 that will be subjected to greater pressures, which could the central zones, differing the texturing from that which will be achieved on the zones that will be subjected to lower pressures, which could be the end zones.

[0172] Once—for a certain position along the axis X of the emitter—it is established that it is necessary to make a correct since at least one distance value does not fall within the acceptability criterion (using for example the values of the normalized vector V and comparing them with the acceptability range (Hx−h2)÷(Hx+h1)), the control unit 15 commands the step of correcting the position of the emitter and, generally, also of the distance sensor 700. In particular, the operation of correcting the position of the laser emitter 600 along the auxiliary direction Z provides for moving the laser emitter 600 close to the lateral surface 2 of the cylindrical body 1 if it results that one or more of the distance values or one or more of the normalized distance values are greater than the maximum distance value. Vice versa, the operation of correcting the position of the laser emitter 600 along the auxiliary direction Z provides for moving the laser emitter 600 away from the lateral surface 2 of the cylindrical body 1 if it results that one or more of the distance values or one or more of the normalized distance values are lower than the minimum distance value. In more detail, the control unit 15 executes a comparison between the elements of the vector Vnormalized=[D.sub.1v, D.sub.2v, . . . D.sub.xv, . . . , D.sub.nv] and the interval (Hx−h2)÷(Hx+h1). With reference to FIG. 10, if the element D.sub.xv is greater than (Hx+h1), the conveying support 400 (which supports at least the laser emitter 600 and preferably both the laser emitter 600 and the distance sensor 700) is moved close to the surface of the cylindrical body 1 with a movement in absolute value for example equal to (D.sub.xv−Hx). If the element D.sub.xv is less than (Hx−h2), the conveying support 400 is moved away from the surface of the cylindrical body 1 with a movement in absolute value equal to (Hx−D.sub.xv). In FIG. 10, the points calculated at the angles α.sub.n, α.sub.n−1, α.sub.n+1, result outside of the tolerance range (Hx+h1)÷(Hx−h2): at these points, therefore, the system will intervene for correcting the position of the laser emitter 600, moving the conveying support 400 away from the surface of the cylindrical body 1.

[0173] As already mentioned above, during the surface processing, the control unit 15 is configured for commanding the movement of the laser emitter 600 and of the distance sensor 700 in a plurality of successive positions along the main direction X. During such movement, the control unit 15 repeats the correction procedure (with the frequency that is deemed opportune for the specific application) at a multiplicity of successive positions taken by the emitter and/or by the distance sensor 700 along the main direction X. In this manner, even if the cylindrical body 1 while rotating can have a lateral surface 2 that is actually eccentric with respect to the actual rotation axis, the control unit 15 is capable of effectively correcting, in a timely manner, such eccentricity by suitably moving the laser emitter 600.

[0174] It should be observed that the apparatus 10 can comprise a plurality of laser emitters and relative distance sensors controlled by the control unit 15 as described above and as claimed below.

[0175] After that described above from a mainly structural standpoint, a process for the surface processing of a cylindrical body 1 according to the aspects of the invention will now be described.

[0176] In accordance with one aspect of the invention, the process for surface processing of cylindrical bodies, in particular for the surface texturing of rolling cylinders, uses the above-described apparatus 10 and is therefore executed under the supervision and control of the control unit 15.

[0177] In practice, without having to repeat in detail all of the steps of the process, regarding which reference is made to the steps executed by the above-described control unit 15, it should be observed that the process for surface processing of the cylindrical body 1 provides, normally after a step of grinding the cylindrical body itself (step S01), for rotating the cylindrical body 1 in the operative seat of the apparatus 10 (step S02). After having created the initial matrix M, maintaining both laser emitter 600 and distance sensor 700 in a starting position (step S1), the movement is commanded of the laser emitter 600 and of the distance sensor 700 along said main direction (X): with the movement of the laser emitter 600, the emission of a laser beam is also activated, directed towards a surface of the cylindrical body 1 rotating in the operative seat, consequently allowing a surface processing of the cylindrical body itself, and achieving the desired texturing (step S2). During the travel of the laser emitter 600 along the main direction X, the correction procedure can be repeated when necessary (i.e. in an asynchronous manner) or at regular intervals or following a predetermined number of complete revolutions of the cylindrical body. The correction procedure (cyclically-repeated procedure P) provides for the various steps and substeps already described with reference to the apparatus 10 and in particular for example the updating of the matrix M (step S3), the verification that the distances, e.g. normalized, of the reference vector are at the acceptability criterion (step S4) and the possible correction of the distance between the emitter and the lateral surface of the cylinder along the auxiliary axis Z (step S5). As stated above, this correction cycle is carried out when suitable, and hence even multiple times during a single rotation of the cylinder. Once the processing is completed, the control unit stops all of the operations of the apparatus in order to allow picking up and unloading the processed cylindrical body (step S6).

[0178] The invention finally regards a computer program which can for example be used on an apparatus 10 for the surface processing of cylindrical bodies in order to suitably program the control unit 15 of such apparatus 10 to execute the above-described operations. In particular the computer program is a software product that comprises instructions which, when the program is executed by a computer or digital control unit, configure such computer as the control unit 15 of the apparatus 10 described above and/or claimed, this rendering such apparatus 10 capable of executing the process described above and/or claimed.

[0179] In accordance with aspects of the invention, a data support is also provided for storing the abovementioned computer program; for example the data support can be or comprise a mass memory such as a hard disk of any nature, a rewritable memory, a volatile memory, a data carrier signal, a memory that is remote with respect to the control unit 15, or a memory of any other kind.

Control Unit

[0180] The plant, the apparatus and the process described and claimed herein use at least one control unit 15 set to control operating conditions implemented by the same plant/apparatus and to control the steps of the process. The control unit 15 can be a single unit or it can be formed by a plurality of separate control units 15 depending on the design selections and on the operating requirements.

[0181] With the term control unit 15 it is intended a component of electronic type which comprises at least one of the following: a digital processor (CPU), a circuit of analog type, or a combination of one or more digital processors with one or more circuits of analog type. The control unit 15 can be “configured” or “programmed” for executing several steps: in practice this can be achieved with any means that allows configuring or programming the control unit 15. For example, in the case of a control unit 15 comprising one or more CPUs and one or more memories, one or more programs can be stored in suitable memory banks connected to the CPU or to the CPUs; the program or programs (software or firmware for example) contain instructions which, when executed by the CPU or by the CPUs, program or configure the control unit 15 to execute the operations described in relation to the control unit 15. Such programs can be written in any one programming language of known type. The CPUs, if two or more in number, can be connected to each other by means of a data connection such that their computing powers are shared in any manner; the CPUs themselves can be installed in positions that are also geographically different, by means of the aforesaid data connection achieving a distributed computing environment. The CPUs can be a processor of general purpose type, configured for executing one or more parts of the process or of the steps described or claimed herein, the program software or firmware, or be an ASIC or dedicated processor, or a FPGA, specifically programmed for executing at least part of the operations described herein. The memory support can be non-transient and can be inside or outside the CPUs, and specifically it can be a memory geographically situated remotely with respect to the computer. The memory support can also be physically divided into multiple portions, or into “cloud” form, and the software program or firmware can physically provide for portions stored on memory portions that are geographically separate from each other.

[0182] Alternatively, if the control unit 15 is or comprises circuitry of analog type, then the circuit of the control unit 15 can be designed for including circuitry configured, during use, for processing electrical signals so as to execute the steps relative to the control unit 15.

[0183] In a preferred embodiment of the invention discussed herein, the control unit is set for operating the entire apparatus and comprises the hardware and software resources necessary for the execution of all the functions necessary for processing and for control, described above. In particular, in a non-limiting example, the control unit comprises at least three different types of processors or CPUs: [0184] a first CPU, usually called CNC (Computer Numerical Control), is dedicated to defining the movements of the various movable parts of the apparatus as a function of the input signals coming from the sensors present (Encoders or others). This CPU is provided with memory cells and is able to manage the writing of the vectors V and the composition of the matrix M; [0185] a second CPU whose main tasks are those of mass archiving system and of managing a man—machine interface, for commanding and monitoring the execution of the operations, as well as for the maintenance and diagnostics of the apparatus; [0186] the third CPU, usually termed PLC (Programmable Logic Controller), is instead involved with the management of the signals, with the execution of commands of the auxiliary systems (pumps, valves, contacts) and with the safety (end stop, protections, maintenance requirements).

[0187] As already mentioned above, even if in one embodiment the functions described are executed by multiple CPUs, each having a respective sub-set of distinct functions assigned thereto, the apparatus can alternatively provide for a single control unit which is involved with all of the functions that are briefly described above.