"METHOD AND SYSTEM FOR AUTOMATIC CUTTING OF FABRIC"

The object of the present invention is a method and system for automatic cutting of one or more overlaid pieces of fabric, typica lly in a predetermined operating window.

There are known machines for the automatic cutting of fabrics which cut a piece or, simultaneously, a stack of overlaid pieces of fabric (called "fabric lay" in the jargon of this field) typica lly to obtain a plurality of shapes of fabric (each of which in a number equa l to the number of overla id layers of fabric) accord ing to the present cutting pattern. These shapes are then used to make various products, includ ing for example garments, u pholstery or fabric for car interiors, etc. These cutting machines comprise a cutting su rface, a cutting head over the cutting surface and movement devices suitable for moving the cutting head along two axes parallel to the cutting su rface, so as to define a cutting area (i .e. , the maximum surface area within which the machine is able to cut) . The cutting head is equipped with cutting members for cutting fa bric, typically a vertica l blade with hig h frequency reciprocating rectilinear movement. A command u nit is connected to the movement devices and to the cutting head so as to command them to cut the piece(s) of fabric laid on the cutting su rface according to a cutting pattern loaded in the command unit. This cutting process can be carried out in a stepped or continuous manner. In the case of a stepped process, each step typically corresponds to a cutting pattern that defines a cutting window, the latter being defined as the area containing the set of shapes constituting the cutting pattern. In a fabric lay, there is typica lly room for a plu rality of cutting windows. Once a cutting pattern has been completed with the fa bric lay being stationary, the fa bric lay is advanced on the cutting surface so that the fabric extends over the entire cutting window that follows. In the case of a continuous process, the above holds, but the cutting window is in continuous movement with respect to the fabric lay.

For automatic cutting, it is important that the fabric be arranged over the cutting su rface so that it extends throug hout the entire cutting window within which the command unit will perform the cutting process. Otherwise, one or more shapes would be incomplete or defective. For example, this happens when the fabric lay is arranged with the sides not parallel to the sides of the cutting area. In this case, even if the first cutting window or windows are entirely within the fabric, there is a risk that in subsequent cutting steps the edges of the cutting windows will be beyond the fabric.

To avoid this, before starting up the cutting process, the operator usually checks to ensure that the fabric lay is sufficiently centred with respect to the cutting area, and particularly that the sides thereof are sufficiently aligned with the sides of the cutting area. For this purpose, the cutting head can be equipped with a laser source suitable for projecting a laser beam on the fabric (typically an X-shaped beam). When performing the first cutting procedure for the fabric lay being processed (and possibly in one or more of the subsequent procedures/working windows), the operator brings the cutting head in proximity to a vertex of the fabric lay and, typically with the aid of the laser, he/she fixes a point of origin, that is, the operator enters this position in the command unit, which thus knows the origin with respect to which the cutting window shall be positioned. The operator then moves the cutting head along a first direction parallel to one side of the cutting area and checks to ensure that the laser beam remains within an acceptable distance from the edge of the fabric lay (for example, the operator ensures that it does not enter the perimeter area of the fabric lay, in which fabric unsuitable for production is present, or that it does not move too far away from the edge of the fabric lay), and possibly, starting from the origin again, along a second direction orthogonal to the first direction, performing the same check. During this procedure, if the laser beam projected on the fabric proves to be too close to the edges of the fabric lay, or beyond the edges, or it moves too far away from the edges, the operator can move (within certain limits) the origin accordingly (thereby repositioning the cutting window). In extreme cases, the fabric lay must be repositioned manually, particularly in order to re-center it and/or realign the sides of the fabric lay more precisely with the sides of the cutting area. The Applicant has found that said method for positioning the cutting window and/or for adjusting the position of the fabric lay is excessively arduous and/or long, thus creating downtime in the fabric processing stage. Moreover, this essentially empirical method involves a certain degree of imprecision. Additionally, in the case of manual positioning of the fabric lay, job safety issues arise when there are heavy loads.

Therefore, as concerns the automatic cutting of a piece of fabric or of a stack of fabric pieces to obtain a plurality of shapes of fabric, the Applicant has addressed the issue of ensuring that the cutting process is performed correctly on the fabric, limiting to a minimum, or eliminating, downtime owing to the need to monitor and/or ensure correct positioning of the fabric with respect to where the machine will be cutting the fabric.

This problem, as well as others which are described herein below, is resolved by a method and a system for the automatic cutting of fabric in accordance with the present invention in various embodiments thereof, as specified below and/or according to that which is claimed in the appended claims, possibly in combination with the following embodiments.

In one aspect, the invention concerns a method for automatic cutting of fabric, comprising :

- providing at least one piece of fabric;

- marking said at least one piece with a marking representative of at least two spatial points on said piece;

- detecting said marking and, through said detected marking, determining a position and an orientation of said at least one piece with respect to a reference system;

- automatically cutting said at least one piece as a function of said determined position and orientation.

In a further aspect, the invention concerns a system for automatic cutting of fabric, comprising :

- a cutting surface suitable for supporting at least one piece of fabric, said cutting surface being associated with a reference system;

- a detection system suitable for detecting a marking, when said at least one piece is laid on said cutting surface, said marking being representative of at least two spatial points on said at least one piece;

- a cutting head for cutting said at least one piece;

- a control system programmed to determine, as a function of said detected marking, a position and an orientation of said at least one piece with respect to said reference system and to command said cutting head for cutting said at least one piece as a function of said determined position and orientation. According to the Applicant, the characteristics stated above, particularly the marking of the piece of fabric so as to represent at least two spatial points, the subsequent detection of this marking to determine the position and orientation thereof, and the automatic cutting of the piece as a function of the position and orientation thus determined, enable very precise automatic cutting of the fabric, avoiding semi-manual control of the positioning of the fabric lay with respect to the cutting area as described above, and/or avoiding or limiting recourse to manual repositioning of the point of origin and/or of the piece/fabric lay. These characteristics can significantly reduce the time needed to check correct positioning of the fabric lay and/or repositioning of the fabric lay, thereby eliminating or reducing processing downtime.

The present invention can offer one or more of the following preferred characteristics in one or more of its aspects.

Preferably, it is envisaged to determine, from said detected marking, a position of said two spatial points with respect to said reference system and to determine, from said determined position of the two spatial points, said position and orientation of said at least one piece.

Preferably, the control system is programmed to determine, as a function of said detected marking, a position of said two spatial points with respect to said reference system and to determine from said determined position of the two spatial points, said position and orientation of said piece.

In this manner, the position and the orientation of the piece can be determined in a completely automatic manner.

Preferably, in order to automatically cut said at least one piece, it is envisaged that a predetermined cutting window provided for said automatic cutting be positioned on said at least one piece as a function of said determined position and orientation.

Preferably, the control system is programmed to place a predetermined cutting window on said at least one piece as a function of said determined position and orientation.

Positioning said predetermined cutting window preferably comprises translating and/or rotating said cutting window on said at least one piece as a function of said determined position and orientation.

This enables optimal and precise positioning of the cutting window automatically. It is clear from the above that the positioning of the cutting window on the piece is typically a virtual positioning procedure that is in itself devoid of any concrete actions on concrete objects. This virtual procedure corresponds to carrying out the corresponding cutting pattern positioned and oriented on the cutting surface, and thus on the fabric lay, as a function of the position and orientation of the fabric lay as determined according to the invention.

Preferably, automatically cutting said at least one piece comprises cutting a plurality of shapes, within said cutting window. Preferably, said control system has loaded a cutting pattern for cutting a plurality of shapes within said cutting window. The cutting head is preferably equipped with a cutting blade. The automatic cutting system preferably comprises a movement system configured to move said cutting head over said cutting surface along two axes that are mutually orthogonal and parallel to said cutting surface. The control system is preferably programmed to command said movement system in order to command said cutting head. In fact, the automatic cutting of the shapes benefits strongly from the reduced time and the precision offered by the present invention.

It is preferably envisaged that a stack of overlaid pieces of fabric comprising said at least one piece of fabric be provided and marked. Said at least one piece is preferably a piece at the top of said stack of pieces. Preferably, said cutting surface is suitable for supporting said stack of pieces. In fact, the simultaneous cutting of a stack of pieces increases productivity. A "stack of overlaid pieces of fabric" is generally understood as a plurality of overlaid layers of fabric, wherein the fabric may vary (e.g. in the material and/or thickness and/or colour and/or ornamental pattern) among the different layers and also within one layer, and wherein the fabric can consist in a number of continuous layers (that is, without cutting between the layers) and/or wherein the number of layers (and thus the height) may vary along the fabric lay.

Said at least one piece and/or stack of pieces typically has a layout with rectilinear sides, preferably two by two parallel; more preferably it has a rectangular (or square) layout. In fact, spreading machines typically realize this type of layout, which also facilitates the process of marking the fabric, for example manually.

Typically, a straight line passing through the two spatial points is in a predetermined relation with a layout of said at least one piece or stack of pieces. In this manner, the orientation of the piece can be determined from the orientation of this straight line in the plane.

Preferably, said straight line is (substantially) parallel to one side of said layout, more preferably parallel to a long side of said layout. Advantageously, in this manner, said straight line visually and intuitively represents the orientation of the piece or the stack of pieces. Note that said predetermined relation is in practice respected with a certain tolerance. For example, this straight line is substantially considered to be parallel to the side of the layout when it forms with the side an angle of less than or equal to 1°, preferably a half degree.

Said marking preferably comprises at least two distinct signs representative of said two spatial points, respectively, more preferably a plurality (greater than two) of distinct signs representative of a respective plurality of spatial points, more preferably said signs are mutually equidistant and (substantially) are aligned along said straight line. Preferably, said signs are affixed in proximity to a lateral edge of a layout of said at least one piece or stack of pieces. In this manner, affixing the marking, possibly even manually, proves to be simpler. Preferably, said at least two distinct signs are different from each other. Preferably, a first sign of said signs is representative of a spatial point of origin, the remaining signs being different from said first sign and representing a respective spatial point of alignment. Said spatial point of origin is preferably positioned in proximity to a vertex of the layout. In this manner, it is possible to easily fix a point of origin on the fabric lay, and with respect to which the automatic cutting and/or the positioning of the cutting window refers.

The present invention encompasses any type of sign, applied, preferably directly but also indirectly (that is, through the interposition of a sheet or another auxiliary element), in any position on the piece or stack of pieces, for example signs traced with a colourant, chemical signs, electromagnetic signs (e.g. RFID, ferromagnetic labels, etc.), passive signs and/or active signs (i.e., capable of sending tracking signals). In a similar manner, the detection system can be implemented with any technology that is compatible with the sign used, for example optical or electromagnetic readers, chemical, magnetic, proximity sensors, wireless receivers, etc.

Preferably each one of said signs is a visual sign (including x's, circles, symbols, codes, etc.).

Preferably, at least one of said marking signs, more preferably said first sign, is also representative of further information that is useful for the cutting procedures, including for example one or more of the following : the type of fabric, the number of layers and the height of the fabric lay.

Preferably, detecting said marking comprises acquiring one or more digital images of said at least one piece and processing said one or more digital imaging in order to recognize said signs and to determine a position of said spatial points with respect to said reference system.

Preferably, said detection system comprises a camera configured to acquire digital images of said at least one piece or portions thereof. Preferably, the control system is programmed to process said one or more digital images in order to recognize said signs and to determine a position of said spatial points with respect to said reference system.

Preferably, said camera is solidly constrained to (for example it is mounted on) said cutting head (so that the movement system is part of the detection system as well). In this manner, space is optimized and costs are reduced, for the same movement system is used for detection of markings and for cutting. Preferably, each one of said signs is a barcode, more preferably a Quick Response (QR) code.

Preferably determining said position of each spatial point with respect to said reference system comprises: acquiring a respective digital image containing the respective visual sign representative of said each spatial point, acquiring a spatial position of a reference point of said image with respect to said reference system (e.g. the central point of said image corresponding to an optical axis of the camera), determining a relative position of said spatial point in said respective image with respect to said reference point, comparing a dimension of said respective visual sign in said image with a real dimension of said respective visual sign in order to obtain a scale of said image, and determining said position of each spatial point with respect to said reference system as a function of said position of said reference point, of said relative position and of said scale.

Preferably marking said at least one piece or said stack of pieces comprises applying (directly or indirectly) onto said at least one piece or said stack of pieces, a plurality of labels, each one being provided with one of said signs. Preferably, said labels are applied in proximity to a lateral edge of a layout of said at least one piece or stack of pieces.

Preferably the system for the automatic cutting of fabric comprises a labelling machine comprising a laying surface for at least one piece or a stack of pieces of fabric, a labelling head, a respective movement system configured to move said labelling head along two orthogonal axes parallel to the laying surface, a command unit programmed to command the movement system and the labelling head to apply (directly or indirectly), onto said at least one piece or said stack of pieces, a plurality of labels in order to realize said marking, each label preferably being provided with at least one of said signs.

Preferably the command unit is programmed to apply the labels as a function of a position and an orientation on the laying surface of the layout of said at least one piece. In this manner, the marking process also takes place automatically, preferably also in the case in which the fabric lay is not aligned with respect to the sides of the laying surface.

Further characteristics and advantages of the present invention will become more apparent from the approximate and thus non-limiting description of several preferred, but not exclusive, embodiments of a method and system for the automatic cutting of fabric in accordance with the present invention. This description refers to the attached drawings, of which :

- Figures la, lb and lc are schematic views of a system for the automatic cutting of fabric in accordance with the present invention, in three respective operative stages.

- Figure 2 shows a label according to the present invention.

- Figures 3, 4a and 4b are conceptual views of the cutting area from above, for the purpose of illustrating the method of the present invention.

A system 1 for the automatic cutting of fabric according to the present invention comprises by way of example (Figure 1) a cutting surface 2 (typically horizontal) suitable for supporting at least one piece of fabric 3 and a plane reference system X, Y associated therewith, and a cutting area 5 (i.e., the maximum area within which the cutting process can be performed, as determined by the structure of the movement system and of the cutting head). For the purposes of descriptive clarity, the origin of the reference system X, Y in the figures is located at a vertex of the cutting area 5. The cutting surface can be a stationary supporting surface or, preferably, the surface of a conveyor belt (unillustrated).

In the examples shown in the figures, the piece of fabric 3 is the piece at the top of a "fabric lay" 4, that is, of a stack of overlaid pieces of fabric, although the present invention also applies to just one piece of fabric. Once again, for the sake of simplicity, all the overlaid pieces of fabric in the examples shown in the figures have the same rectangular layout, although in more general terms, one layer of fabric can be made up of two or more distinct pieces, or the number of layers (and thus the height) can vary along the fabric lay. The fabric lay 4 has a rectangular layout, although the present invention applies to any shape of the layout, provided that it is without circular symmetry. Preferably the automatic cutting system 1 comprises a cutting head 11 equipped with a cutting blade (unillustrated) and a movement system 12 configured to move the cutting head over the cutting surface along two orthogonal axes parallel to the cutting surface. The movement system can for example comprise a bridge 13 over the cutting area 5 and that slides back and forth along the X direction, the cutting head being mounted on the bridge so as to enable it to slide back and forth on the bridge 13 along the Y direction. The movement system and the cutting head are not described or illustrated in further detail as they can be of a known type for example.

The cutting system 1 further comprises a detection system 6 suitable for detecting a marking 7 representative of at least two spatial points 8, 9 on the piece 3.

In the examples shown in the figures, the marking 7 is realized by a series of labels 20 applied onto the piece 3 and arranged in proximity to a lateral edge 24 of the piece, and aligned and evenly spaced with respect to each other. An example of a label 20 bearing a QR code 21 is shown in Figure 3.

The QR code constitutes an example sign that is representative of a specific point 22, the relative position of which with respect to the QR code can be chosen arbitrarily. In the example, the point 22 was chosen on a straight line passing through a diagonal of the QR code and at a predetermined distance from the closest vertex. Once the label has been applied, the spatial position of the point 22 identifies a respective spatial point on the piece 3.

By way of example, the series of labels 20 comprises a first label 25 affixed in proximity to a first vertex of the piece 3 (the vertex in the lower right in Figures 3 and 4a-4b) containing a first sign (for example, the QR code 31 shown in Figure 3, the information content of which is the letter "O" for "origin) representative of a first spatial point 8 on the piece 3 and called the "point of origin" (indicated in the figures by a small circle), and a plurality of remaining labels, all containing a second sign, differing from the first sign (for example, the QR code whose information content is the letter "A" for "alignment") and representing a respective spatial point on the piece 3 (indicated in the figures by an "x"). For explanatory purposes, these remaining labels include a second label 26 representative of a second spatial point 9 on the piece 3 and called the "point of alignment" (arbitrarily chosen in the figures). The labels 20 are arranged on the piece 3 so that the respective spatial points prove to be substantially aligned along a straight line 23 oriented according to a predetermined spatial relation with the layout of the fabric lay. In the example shown, the straight line 23 is parallel to the long side 24 of the fabric lay. The present invention also encompasses alternative solutions (not shown) in which for example the labels are applied on the vertical flanks of the fabric lay, or in which the straight line 23 is arranged along a diagonal of the fabric lay and/or parallel to the short side.

Additionally, solutions encompassed by the present invention (unillustrated) envisage the use of signs differing from the QR code, including a linear barcode, or directly an x or a small circle (in which case the images acquired are processed through suitable algorithms for recognizing these signs, as known in the prior art).

Note that the x's and the small circle illustrated in Figures la-c, 3 and 4a-4b are purely illustrative examples of spatial points and do not necessarily reproduce the real appearance of the labels in the example described here. As explained above, the labels 20 show a respective QR code as shown in Figure 2.

In addition, the signs can be traced (unillustrated) on the piece, for example drawn or printed, rather than applied by means of a label. Moreover, the signs can be affixed directly onto the fabric constituting the fabric lay 4, or onto an auxiliary sheet (e.g. a sheet of paper) arranged at the top of the fabric lay (in this case, the marking is said to be affixed indirectly onto the piece 3).

The present invention also encompasses solutions (unillustrated) in which at least one of said markings signs, preferably the first sign, is representative of further information useful for the cutting procedures, including for example the type of fabric, the number of layers, the height of the fabric lay, etc. For example, in addition to or as an alternative to said letters "O" and/or "A", the QR code can encode this information. This information can be subsequently used to configure the cutting parameters, including the blade advancement speed, oscillation frequency or sharpening times.

In a further solution (unillustrated) that falls within the scope of the present invention, rather than applying a series of labels, a line (a solid or a broken line, preferably a straight line) is traced on the fabric lay with a predetermined relation with respect to the layout (e.g. parallel to the long side). This line can have at least one predetermined spatial point (e.g. an endpoint of the line), which can function as a point of origin, or it can extend for the entire length of the fabric lay. In this latter case, the operator can manually enter a spatial point on the fabric lay (preferably on the line) as a point of origin in the control system. The method will thus detect the line (for example, with known techniques for processing the images) to determine the orientation of the fabric lay with respect to the axes X and Y.

The detection system 6 preferably comprises a camera 10 configured to acquire digital images of the piece 3, consistent with the fact that the QR code is, in the example, a visual sign.

In one embodiment (unillustrated), the camera is fixed with respect to the cutting area and it has an optical field such as to acquire the entire cutting area with just one or a few digital images. In this manner, the marking can be detected through the processing of this/these image/s.

As in the illustrated examples, in an alternative embodiment, the camera 10 is solidly constrained to the cutting head, for it is rigidly mounted on the latter, in such a manner that it too can be moved by the movement system 12. Advantageously, the camera 10 has an optical axis 15 that is perfectly orthogonal to the cutting area 5.

The cutting system 1 comprises a control system 100 (for example, comprising a command and control computer alongside the cutting system and suitable electronics) programmed to determine, as a function of the detected marking 7, the position and the orientation of the piece 3 with respect to the reference system X, Y and to command the cutting head 11 for cutting the piece 3 or the fabric lay 4 as a function of the position and orientation thus determined. The control system 100 is preferably programmed to command the movement system 12 in order to command the cutting head.

In a preferred embodiment, the system for the automatic cutting of fabric 1 comprises a labelling machine (unillustrated) comprising a laying surface (typically horizontal and realized by a conveyor belt) for the piece 3 or the stack 4 of pieces of fabric, a labelling head, a respective movement system configured to move the labelling head along two axes that are mutually orthogonal and parallel to the laying surface, a command unit (e.g. a computer) programmed to command the movement system and the labelling head to apply a plurality of labels 20 onto the piece or stack of pieces, each label bearing one of said signs 21. The laying surface can typically be the spreading surface of a fabric spreading machine. The labelling machine is not described or illustrated in further detail as it is already known per se.

In operation, the automatic cutting system 1 described above implements an exemplary method for the automatic cutting of fabric according to the present invention.

First of all, the method comprises marking the stack 4 with the marking 7 representative of at least two spatial points 8, 9 on the stack 4.

Marking the stack 4 preferably comprises applying (directly or indirectly) the said plurality of labels 20 on the top piece 3.

In one embodiment, the labels 20 are applied manually by an operator. In this case, the operator applies the labels so that the spatial points that the labels define on the piece 3 are aligned as much as possible with respect to each other and with the long side 24. For example, with this aim, the operator arranges all the labels at about the same distance from the lateral edge 24 (for example, so that all the fabric to be discarded is found between the labels and the edge).

In a preferred embodiment, the labels 20 are applied automatically by a labelling machine. For this purpose, a point of origin (for example near the first vertex) and an orientation of the piece or stack of pieces on the laying surface are initially entered preferably in the command unit manually (for example, by manually entering a second point of alignment in proximity to the vertex opposite the first vertex), so that the straight line 23 passing through the spatial points on the labels proves to be parallel to the side 24. Following the marking process, the stack 4 is placed on the cutting surface 2 so that the end portion of the stack is found in the cutting area 5; said end portion of the stack comprises the first vertex in the proximity of which said first label 25 is found.

At this point, the detection of the marking is envisaged.

With this aim, the control system 100 initially moves the camera 10 (for example, with a zigzag movement of the cutting head 11) so as to scan a portion of the piece 3 adjacent to the first vertex containing the point of origin 8, acquiring the relative digital images of the piece (typically acquired by electronics on board the camera), until the QR code of the first label has completely entered the optical field of the camera (Fig. la). When the control system (e.g. the electronics on board the camera) recognizes the QR code, the control system stops the cutting head and the camera. For example, the electronics on board the camera send an acquired QR code signal to the command and control computer and the computer sends a stop signal to the cutting head and receives a stop confirmation signal from the latter. At that point, the control system 100 acquires the position of the camera (for example, the spatial coordinates of the optical axis 15 with respect to the system X, Y) and a digital image containing the QR code and proceeds to process it so as to determine the real position of the spatial point 8 with respect to the system X, Y, and said point 8 is acquired as the point of origin. For this purpose, the control system determines the relative position of the spatial point 8 represented by the QR code within the digital image (for example, the relative position of the spatial point 8 with respect to the point in the image corresponding to the optical axis 15). Moreover, a relative dimension of the QR code in the image (for example the number of pixels occupied by the diagonal or by a side of the QR code) is compared with the known corresponding real dimension to obtain the scale of the image (in other words, the real dimensions corresponding to a single pixel in the image are determined. With this datum, the real position of origin 8 with respect to the optical axis 15 can be determined, and from there the real position of the point of origin 8 with respect to the reference system X, Y. Moreover, from this datum, the height of the fabric lay can be determined and the height can be used to command the cutting procedures, for example to configure parameters such as speed, oscillation frequency or sharpening times of the blade.

Subsequently, the camera is moved rapidly, preferably along the X axis, as far as the opposite vertex of the cutting area 5 (Fig. lb), preferably without detecting the marking, and from there it is moved in reverse again towards the first vertex, this time repeating the scanning procedures stated above until the QR code of the second label 26 has completely entered the optical field of the camera (Fig . lc). By completing the procedures described above with reference to the first label, the real position of the second spatial point 9 is determined with respect to the system X, Y and the second spatial point 9 is acquired as a "point of alignment". In this manner, the control system 100 acquires the direction of the straight line 23 and thus of the side 24 of the fabric lay. The exemplary method described above, which detects the label useful for alignment and furthest from the point of origin, makes it possible to determine the orientation of the fabric lay with the greatest possible precision. In conclusion, having determined the real position of the point of origin 8 (and thus the position of the piece 3 or of the stack of pieces 4) and by means of the point of alignment 9, the orientation in the cutting surface 2 of the side 24 (and thus the orientation of the piece 3 or of the stack of pieces 4), the position and the real orientation of the fabric lay with respect to the system X, Y are determined and thus prove to be acquired by the control system 100. At this point, the control system provides for automatically cutting the fabric lay as a function of the determined position and orientation, preferably with the aim of obtaining a plurality of shapes within a predetermined cutting window 30 (Fig. 3, 4a and 4b).

The procedure can be described in terms of positioning the cutting window as a function of the determined position and orientation. As stated, the expression "positioning the cutting window" is to be understood in a figurative sense. The control system typically carries out the cutting procedures according to a preloaded cutting pattern, which is adapted to the position and orientation as determined previously.

Figure 3 illustrates a situation in which the fabric lay is located on the cutting surface with the sides parallel to the axes X, Y and centred with respect to the cutting area. In this case, the control system positions the cutting window 30 in relation to the point of origin 8 (for example a vertex of the cutting window is overlaid on the point of origin) and this is generally sufficient to have the fabric of the fabric lay extend over the entire cutting window 30.

Figures 4A and 4B show a situation in which the fabric lay is located on the cutting surface with the long sides not parallel to the X axis (as also shown in Figures la-lc). Note that the misalignment has been exaggerated in the figures for the sake of descriptive clarity. In reality the angle formed by the straight line 23 and the side 24 is smaller, typically on the order of a few degrees.

In this case, by sole translational movement of the cutting window over the cutting surface, it is not possible to position the window without the window moving beyond the fabric lay (as indicated by the two dotted ellipses). This situation tends to worsen with advancement of the fabric lay (leftwards in the figures) for cutting in the subsequent cutting windows.

By rotating the cutting window 30 appropriately, the state in which the fabric lay extends throughout the entire cutting window is restored, without it being necessary to reposition the fabric lay.

Once the cutting process is completed in the first cutting window, the piece 3 or stack pieces 4 is typically advanced (for example with a conveyor belt at the cutting surface 2) for a suitable length, so that new fabric is found in the cutting area 5 for the subsequent cutting stage. Preferably, a detection procedure for detecting the marking and for determining the new orientation of the fabric lay 4 is carried out once again. For this purpose, preferably the spatial position occupied by the previous point of alignment 9 is taken as a new point of origin after advancement of the fabric lay 4, preferably calculated by the control system 100 without the use of the detection system 6 (in that this advancement takes place along the X axis). Instead the system proceeds as described above to detect the label 20 closest to the opposite end of the cutting area and to determine therefrom the real position of the respective spatial point. In this manner, the position and orientation of the stack of pieces 4 are redetermined, as a function of which cutting is carried out in the subsequent cutting window.