Abstract
The invention relates to machines and methods for the separative machining of a plate-shaped workpieces. The machine includes a first movement device for moving the workpiece in a first direction (X), a second movement device for moving a machining head, which directs the machining beam onto the workpiece, along a second direction (Y), Between workpiece bearing faces there is formed a gap for the passage of the machining beam. In the machine, mutually facing side edges of at least two of the workpiece bearing faces are oriented non-perpendicularly and non-parallel with respect to the first direction (X).
Claims
1. A machine for the separative machining of a plate-shaped workpiece by a processing beam, the machine comprising: a machining head configured to direct the processing beam onto the plate-shaped workpiece; a first movement device configured to bidirectionally move the plate-shaped workpiece in a first direction (X); a second movement device configured to bidirectionally move the machining head in a second direction (Y); and at least two workpiece support units including at least two workpiece bearing faces for supporting the workpiece, a gap configured for the passage of the processing beam being formed between the workpiece bearing faces, wherein mutually facing side edges of at least two of the workpiece bearing faces are oriented non-perpendicularly and non-parallel with respect to the first direction (X).
2. The machine of claim 1, wherein the mutually facing side edges that are oriented non-perpendicularly and non-parallel with respect to the first direction (X), are formed on two stationary workpiece bearing faces (4, 5).
3. The machine of claim 2, wherein the side edges of the two stationary workpiece bearing faces are oriented at an angle (α.sub.Y) with respect to the second direction (Y).
4. The machine of claim 1, further comprising a drive unit configured to displace the machining head in the first direction (X).
5. The machine of claim 1, wherein at least two movable support carriages are positioned between the two stationary workpiece bearing faces), wherein the at least two movable support carriages have in each case one workpiece bearing face for supporting workpiece parts that are cut during the cutting machining process, and wherein those side edges of the workpiece bearing faces of the support carriages that face toward one another are oriented non-perpendicularly and non-parallel with respect to the first direction (X).
6. The machine of claim 5, wherein the side edges of the two stationary workpiece bearing faces are oriented perpendicularly with respect to the first direction (X).
7. The machine of claim 5, wherein the mutually facing side edges of the workpiece bearing faces of the at least two support carriages run rectilinearly and at an angle (α.sub.X) with respect to the first direction (X).
8. The machine of claim 7, wherein the side edges of the workpiece bearing faces of the at least two support carriages run at an angle (α.sub.X) of between 20° and 40° with respect to the first direction (X).
9. The machine of claim 5, wherein the mutually facing side edges of the workpiece bearing faces of the at least two support carriages run in arcuate fashion.
10. The machine of claim 5, wherein at least one of the mutually facing side edges of the workpiece bearing faces of the at least two support carriages has a beveled edge.
11. The machine of claim 5, wherein at least one support carriage of the at least two support carriages, on its bottom side averted from the workpiece bearing face, tapers toward the side edge of the workpiece bearing face.
12. The machine of claim 5, wherein the workpiece bearing face of at least one support carriage of the at least two support carriages is formed, at the side edge of the workpiece bearing face, from a metallic material.
13. The machine of claim 12, wherein the metallic material comprises copper.
14. The machine of claim 5, wherein the workpiece bearing face of at least one support carriage of the at least two support carriages has a plate-shaped subregion on which the side edge of the workpiece bearing face is formed.
15. The machine of claim 5, wherein the workpiece bearing face of the at least one support carriage of the at least two support carriages has a subregion in the form of a corrugated sheet.
16. The machine of claim 5, further comprising: a control device configured to cause at least one support carriage of the at least two support carriages to be positioned under a workpiece part that is to be cut off during the separative machining.
Description
DESCRIPTION OF DRAWINGS
[0036] FIGS. 1A and 1B are illustrations of a laser-processing machine with two stationary workpiece bearing faces, the mutually facing side edges of which are oriented at an angle with respect to a first direction (X direction) along which a workpiece that is to be machined by cutting is moved.
[0037] FIG. 2 is an illustration of a detail of a machine similar to one shown in FIGS. 1A and 1B, in the case of which two mutually independently movable support carriages are arranged in a gap formed between the two stationary workpiece bearing faces.
[0038] FIGS. 3A and 3B are illustrations of two support carriages, the mutually facing side edges of which are oriented parallel to the X direction, during the separation of two workpiece parts by cutting.
[0039] FIGS. 4A and 4B are illustrations of a laser-processing machine with two stationary workpiece bearing faces, the side edges of which are oriented perpendicularly with respect to the X direction and between which there are arranged two movable support carriages, the mutually facing side edges of which are oriented at an angle with respect to the X direction.
[0040] FIG. 5 is an illustration of two support carriages, the mutually facing side edges of which run in arcuate fashion.
[0041] FIG. 6 is a diagram showing the cost and the benefit of the oblique orientation of the side edges of the two support carriages as a function of the angle with respect to the X direction.
[0042] FIGS. 7A and 7B are illustrations of two support carriages, the mutually facing side edges of which have a rounding or a bevel.
[0043] FIGS. 8A and 8B are illustrations of a support carriage, the workpiece bearing face of which has three differently formed subregions.
DETAILED DESCRIPTION
[0044] In the following description of the drawings, identical reference signs will be used for identical or functionally identical components.
[0045] FIGS. 1A and 1B show an exemplary construction of a machine 1 for the laser machining, more specifically for the laser cutting, of a plate-shaped workpiece 2 (illustrated by dashed lines) by means of a laser beam 3. For the cutting machining of the workpiece 2, instead of the laser beam 3, use may also be made of some other type of thermal machining beam, for example a plasma torch, or a water jet. During the machining, the workpiece 2 lies on two stationary workpiece bearing faces 4, 5 that, in the example shown, form the top sides of two workpiece tables and define a bearing plane E (X-Y plane of an XYZ coordinate system) for bearing the workpiece 2. The workpiece bearing faces 4, 5 may be formed by table surfaces or by pin-like bearing elements (pins), bearing belts, brushes, rollers, balls, air cushions or the like.
[0046] By means of a conventional movement and holding device 7, which has a drive and clamping devices 8 in the form of clamping brackets for holding the workpiece 2, the workpiece 2 can be displaced in controlled fashion on the workpiece bearing faces 4, 5 in a first direction X (hereinafter referred to as X direction) and moved to a predefined workpiece position W. To facilitate the movement of the workpiece 2 in the X direction, it is possible for brushes, balls or slide rollers, which constitute the actual workpiece bearing faces 4, 5, to be mounted on the workpiece tables shown in FIG. 1. Alternatively, it is for example possible, for the movement or for assisting the movement of the workpiece 2 in the X direction, for the workpiece bearing faces 4, 5 themselves to be configured as a movement device, for example in the form of a (revolving) conveyor belt, as is described, e.g., in the applicant's DE 10 2011 051 170 A1, or in the form of a workpiece bearing as described, e.g., in JP 06170469.
[0047] Between the two stationary workpiece bearing faces 4, 5 there is formed a gap 6, which is oriented at an angle αY with respect to the Y direction, as can be seen in particular from FIG. 1B. The gap 6 is delimited laterally by two mutually facing side edges 4a, 5a, which in the example shown are oriented parallel, of the stationary workpiece bearing faces 4, 5. The gap 6 extends in a second direction (hereinafter referred to as Y direction) over the entire width of the two workpiece bearing faces 4, 5. A laser cutting head 9 that directs and focuses the laser beam 3 on the workpiece 2 is movable in controlled fashion in the Y direction by means of a driven carriage 11 that serves as movement device and that is guided on a stationary portal 10. In the example shown, the laser cutting head 9 is additionally also movable in the X direction and may be movable in controlled fashion in the X direction by means of an additional movement device 12, for example in the form of a linear drive, which is mounted on the carriage 11. The maximum movement travel of the laser cutting head 9 corresponds to the extent of the gap 6 in the X direction. As can be seen in FIG. 1B, the extent is greater than the width b of the gap 6 owing to the orientation of the gap 6 at the angle αY with respect to the Y direction.
[0048] By means of the movement devices 11, 12 constructed one upon the other, the laser cutting head 9 can be positioned both in the X direction and in the Y direction at a desired cutting head position XS, YS within the gap 6. The laser cutting head 9 can possibly also be displaced along a third movement direction Z (gravitational force direction, hereinafter referred to as Z direction) to adjust the spacing between a machining nozzle 9a of the laser cutting head 9 and the workpiece surface.
[0049] As can be seen in FIG. 1A, the laser beam 3 passes through between the two side edges 4a, 5a, which laterally delimit the gap 6, of the stationary workpiece bearing faces 4, 5 in order to machine the workpiece 2 by cutting. As can likewise be seen in FIGS. 1A and 1B, the plate-shaped workpiece 2 (metal sheet) commonly has a rectangular geometry, and the outer edges of the workpiece 2 run parallel or perpendicular to the X direction. Also, a majority of the workpiece parts separated from the workpiece 2 by cutting commonly have approximately rectangular outer dimensions and—if present—inner contours oriented at a 0° or 90° angle with respect to the outer edges of the workpiece 2.
[0050] The rotation of the gap 6 relative to the X direction and Y direction and thus relative to the outer edges of the workpiece 2, i.e., in relation to the normal position of the parts, considerably reduces the likelihood of occurrence of sheet-metal tongues hanging into the gap 6, because only elongate, narrow contour regions of workpiece parts, which extend parallel to the direction of the gap 6, i.e., whose longitudinal side runs substantially at the angle αY with respect to the Y direction, are at risk of hanging into the gap 6. For the support of the workpiece 2 or of workpiece parts that have been separated from the workpiece 2 by cutting during the cutting machining process, it is thus advantageous if the two side edges 4a, 5a of the stationary workpiece bearing faces 4, 5 are oriented at an angle αY with respect to the Y direction, i.e., are neither perpendicular nor parallel to the Y direction. The angle αY enclosed by the side edges 4a, 5a of the stationary workpiece bearing faces 4, 5 with the Y direction can lie between 0° and 45°, between 20° and 40°, or between 25° and 35°.
[0051] For additional support of the workpiece 2, more specifically for supporting workpiece parts that are cut during the cutting machining process, it is possible, as illustrated in FIG. 2, for two support carriages 13a, 13b to be arranged in the gap 6 shown in FIGS. 1A and 1B. The two support carriages 13a, 13b extend in each case over the entire width b of the gap 6, and are movable in controlled fashion independently of one another in the gap 6 in a displacement direction R that runs at the angle α.sub.Y with respect to the Y direction. The controlled movement of the support carriages 13a, 13b between the side edges 4a, 5a of the stationary workpiece bearing faces 4, 5 may be performed, for example, by means of spindle drives, wherein the spindle nut is attached to the respective support carriage 13a, 13b and the spindles and the drive motor are attached to one of the two stationary workpiece bearings 4, 5. The controlled movement of the support carriages 13a, 13b may also be realized in other ways in accordance with particular implementations.
[0052] The support carriages 13a, 13b can be moved in the gap 6 in each case to a desired position R.sub.UA, R.sub.UB along the displacement direction R, to support the workpiece 2, more specifically workpiece parts that are to be separated from the workpiece 2 by cutting or that have been cut during the machining process, by means of a workpiece bearing face 14a, 14b attached to the respective support carriage 13a, 13b. In the situation shown, the workpiece bearing face 14a, 14b of a respective support carriage 13a, 13b terminates flush with the workpiece bearing faces 4, 5 in the Z direction, e.g., the workpiece bearing faces 14a, 14b of the support carriages 13a, 13b are situated in the bearing plane E for the workpiece 2 (see FIG. 1A). In the example of a machine 1 for cutting machining as shown in FIG. 2, the gap 6 through which the laser beam 3 passes is formed between the movable workpiece bearing faces 14a, 14b of the two support carriages 13a, 13b and the side edges 4a, 5a of the two stationary workpiece bearing faces 4, 5.
[0053] To control the cutting machining process, the machine 1 has a control device 15 that serves for coordinating the movements of the workpiece 2, of the laser cutting head 9 and of the support carriages 13a, 13b in order to set a desired workpiece position W, a desired cutting head position XS, YS and a desired position R.sub.UA, R.sub.UB of the support carriages 13a, 13b in order to permit the cutting of a predefined cut contour and support the workpiece in the vicinity of the gap 6 as necessary.
[0054] The movement of the support carriages 13a, 13b may be performed synchronously, i.e., the spacing between the position R.sub.UA of the first support carriage 13a and the position R.sub.UB of the second support carriage in the displacement direction R is constant during the movement. The movement of the first support carriage 13a may also be performed independently of the movement of the second support carriage 13b, i.e., the spacing between the position R.sub.UA of the first support carriage 13a and the position R.sub.UB of the second support carriage 13b in the displacement direction R varies during the movement along the displacement direction R.
[0055] By means of the orientation of the two side edges 4a, 5a of the stationary workpiece bearing faces 4, 5 at the angle αY with respect to the Y direction, the gap 6 is rotated relative to the position of the workpiece 2 in the XY plane. The mutually facing side edges 16a, 16b, which delimit the gap 6, of the two support carriages 13a, 13b therefore also run obliquely with respect to the outer edges of the workpiece 2 in the case of the square geometry of the two support carriages 13a, 13b, or of the workpiece bearing faces 14a, 14b thereof, shown in FIG. 2.
[0056] By contrast, FIG. 3A shows the situation in which the two stationary workpiece bearing faces 4, 5, or the mutually facing side edges 4a, 5a thereof, are oriented parallel to the Y direction. During the separation of a workpiece part 18 by cutting along the cut contour 17 thereof, which runs parallel and perpendicular to the X direction, a situation may arise in which, in the end position in which the workpiece part 18 has been entirely separated from the remaining workpiece at a separation-by-cutting position FP, the workpiece part lies only on the workpiece bearing face 14b of one of the two support carriages 13b, such that the workpiece part is supported only in that subregion of the workpiece bearing face 14b that is illustrated by hatching in FIG. 3A. The action of the cutting gas, or the action of pressure thereof, in the region of the separation-by-cutting position FP gives rise to a risk of tilting of the workpiece part 18 that has been separated by cutting. Furthermore, the workpiece part 18 may bend downward in the region of the separation-by-cutting position FP.
[0057] Also, in the example shown in FIG. 3B, in which the workpiece part 18 that has been separated by cutting lies on the workpiece bearing faces 14a, 14b of both support carriages 13a, 13b, in the case of the contour 17 of the workpiece part 18 shown in FIG. 3B, which has three tongue-like subregions extending in the X direction, a situation may arise in which the central tongue-like subregion, which is arranged in the gap 6 and that is not supported by the two workpiece bearing faces 14a, 14b, bends and in so doing hangs downward into the gap 6. In this case, during the displacement of the support carriages 13a, 13b, a collision with the non-supported tongue-like subregion can occur.
[0058] The orientation of the mutually facing side edges 16a, 16b of the workpiece bearing faces 14a, 14b of the two support carriages 13a, 13b parallel to the X direction, as shown in FIGS. 3A and 3B, can thus, in the case of workpiece parts whose outer contour 17 is oriented perpendicular or parallel to the X direction, lead to restrictions in process reliability.
[0059] To avoid these problems, in the case of the machine 1 shown in FIGS. 4A and 4B, the two mutually facing side edges 16a, 16b, which are oriented parallel, of the workpiece bearing faces 14a, 14b of the two support carriages 13a, 13b are oriented obliquely, e.g., at an angle α.sub.X with respect to the X direction. By contrast, in the case of the machine 1 shown in FIGS. 4A and 4B, the two mutually facing side edges 4a, 5a of the stationary workpiece bearing faces 4, 5 of the workpiece bearing tables run, as in FIGS. 3A and 3B, parallel to the Y direction, such that the two support carriages 13a, 13b can be moved in each case to a desired position Y.sub.UA, Y.sub.UB in the Y direction to support the workpiece 2 or a workpiece part 18 that is to be separated by cutting. The actuation of the support carriages 13a, 13b and of the further movable components is performed by means of the control device 15 in the manner described further above in conjunction with FIGS. 1A and 1B.
[0060] In the example shown in FIG. 4A, in each case one covering element 19a, 19b for covering the intermediate space between the two workpiece bearing faces 4a, 4b outside the gap 6 formed between the support carriages 13a, 13b is attached to the support carriages 13a, 13b, more specifically to the mutually averted side edges, running in the X direction, of the workpiece bearing faces 14a, 14b. The covering elements 19a, 19b extend over the entire width b of the gap 6, are moved conjointly in the Y direction during the movement of the support carriages 13a, 13b, and, in the example shown, are formed in the manner of a roller shutter. The covering elements 19a, 19b may also be of some other form, for example of telescopic form, of scale-like form, in the form of a rolled-up band, etc. The top side of the covering elements 19a, 19b is situated at the level of the workpiece bearing faces 14a, 14b or of the workpiece bearing faces 4, 5. The covering elements 19a, 19b serve for bearing non-stiffened subregions, which project into the gap 6, of the remaining workpiece 2, which, if not borne in this way, could possibly collide with the support carriages 13a, 13b. It is self-evident that covering elements 19a, 19b may also be used in the example shown in FIG. 2 as bearings for overhanging subregions of the remaining workpiece 2.
[0061] As shown in FIG. 4B, by means of the orientation of the mutually facing side edges 16a, 16b of the workpiece bearing faces 14a, 14b of the support carriages 13a, 13b at an angle α.sub.X with respect to the X direction, it is possible, by contrast to the example shown in FIG. 3A, for a workpiece part 18, the outer edges of which are oriented parallel or perpendicular to the X direction or Y direction, to be supported by the workpiece bearing faces 14a, 14b of both support carriages 13a, 13b, in order to thereby increase the process reliability.
[0062] In the example shown in FIGS. 4A and 4B, however, owing to the side edges 16a, 16b of the workpiece bearing faces 14a, 14b of the two support carriages 13a, 13b being oriented at an angle α.sub.X with respect to the X direction, in the event of a movement of the machining head in the X direction, it is necessary for the support carriages 13a, 13b to be moved in the Y direction in order that the position of the gap 6 situated between the two support carriages 13a, 13b follows the movement of the laser cutting head 9. Therefore, in the actuation of the support carriages 13a, 13b, it is necessary for the position of the “tool center point” of the X-axis movement (workpiece axis+additional axis in the X direction) to be implemented in transformed form.
[0063] As can be seen from the lower curve in the graph of FIG. 6, the required movement travel and thus the ratio D of the required dynamics of the support carriages 13a, 13b to the original dynamics becomes greater the greater the angle α.sub.X (between 0° and 45°) between the respective side edges 16a, 16b of the workpiece bearing faces 14a, 14b and the X direction. The process reliability Q, i.e., the certainty that a workpiece part 18 of arbitrary shape is always supported by the workpiece bearing faces 14a, 14b of both support carriages 13a, 13b during the cutting of the contour 17 of the workpiece part, likewise increases with increasing angle α.sub.X, as can be seen in FIG. 6 on the basis of the upper curve (in %). A good compromise between support action or process reliability Q and required dynamics D for the movement of the support carriages 13a, 13b in the Y direction is achieved with an angle α.sub.X between approximately 20° and 40°, e.g., between 25° and 35°, for example, with an angle α.sub.X of approximately 30°.
[0064] As an alternative to the example shown in FIGS. 4A and 4B, in which the two mutually facing side edges 16a, 16b of the support carriages 13a, 13b run rectilinearly, it is the case in an example shown in FIG. 5 that the two mutually facing side edges 16a, 16b of the two support carriages 13a, 13b are of arcuate or curved form. In this way, the parallelism between the mutually facing side edges 16a, 16b of the bearing faces 14a, 14b of the support carriages 13a, 13b and the outer or inner contours of cut workpiece parts 18 can be yet further reduced, whereby the risk of sections or segments of the workpiece parts 18 hanging downward into the gap 6 between the two support carriages 13a, 13b is also further reduced.
[0065] For effective prevention of collisions between downwardly hanging sections of workpiece parts 18 and the support carriages 13a, 13b, it has proven to be advantageous if the mutually facing side edges 16a, 16b of the two workpiece bearing faces 14a, 14b of the support carriages 13a, 13b have a rounding 20 or a bevel 21, cf. FIGS. 7A and 7B. The rounding 20 shown in FIG. 7A has a radius of curvature R of approximately 2-5 mm. The bevel 21 shown in FIG. 7B extends from the workpiece bearing face 14a, 14b approximately 3 mm downward in the Z direction and approximately 4.5 mm in the Y direction as far as the side edge 16a, 16b of the respective support carriage 13a, 13b. In the examples shown in FIGS. 7A and 7B, a (minimum) spacing D between the two support carriages 13a, 13b, which may, for example, be approximately 4-5 mm, is smaller than a spacing A between the planar workpiece bearing faces 14a, 14b, which may, for example, be approximately 10-12 mm.
[0066] To minimize the adhesion of slag to a respective support carriage 13a, 13b, it is advantageous if the support carriages 13a, 13b, at their bottom side 22a, 22b averted from the workpiece bearing face 14a, 14b, taper toward the respective side edge 16a, 16b of the workpiece bearing face 14a, 14b, or if the support carriages have an (oblique) recess, as is likewise illustrated in FIGS. 7A and 7B.
[0067] To further reduce the adhesion of slag, it is likewise advantageous for the side edge 16b of a respective support carriage 13b to be formed from copper, because this material exhibits good thermal conductivity and the slag formed during the cutting of steel and aluminum does not adhere well to copper. To produce the side edge 16a, 16b of one of the support carriages 13a, 13b from copper as material, there are numerous possibilities. In the example shown in FIGS. 8A and 8B, a copper sheet 23 is attached to the (second) support carriage 13b, which copper sheet is detachably fastened to the support carriage 13b, for example by means of a screw connection, and can be exchanged if necessary.
[0068] In the example shown in FIGS. 8A and 8B, the workpiece bearing face 14b of the support carriage 13b is divided into three parts and has a first, plate-shaped subregion T1, on which the side edge 16b is formed and that forms an upper section of the copper sheet 23. plate-shaped first subregion T1 is adjoined by a second subregion T2, which in the example shown is in the form of a corrugated sheet 24, which permits stable bearing of a workpiece and that exhibits good sliding characteristics. The corrugated sheet 24 is directly adjoined in the Y direction by a third subregion T3 of the workpiece bearing face 14b, which third subregion is in the form of a brush-type bearer 25 and has a multiplicity of brushes that are flexible and facilitate sliding of workpieces 2 lying on the workpiece bearing face 14b.
[0069] The plate-shaped first subregion T1 makes it possible for the tapered bottom side 22b of the support carriage 13b to be offset from the side edge 16b of the workpiece bearing face 14b by a distance d, whereby the adhesion of slag to the support carriage 13b or to the copper sheet 23 can be reduced. It is self-evident that the first support carriage 13a may also be designed in the manner shown in FIGS. 8A and 8B. By means of the second subregion T2, the spacing between the side edge 16b and the brush-type bearer 25 is additionally increased, in order to prevent damage of the brushes by flying sparks.
[0070] In summary, by means of the neither parallel nor perpendicular orientation of at least two side edges 4a, 5a or 16a, 16b, which delimit the gap 6, of the respective workpiece bearing faces 4, 5 or 14a, 14b with respect to the outer edges of the workpiece 2 or with respect to the X direction during the cutting machining process, in particular during the separation by cutting, it is possible for improved, areal support of workpiece parts 18 to be realized.
Other Embodiments
[0071] A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
