METHOD FOR CUTTING AT LEAST ONE PIECE FROM A SHEET OF TIN

Description

[0001] The invention relates to a method for cutting out at least one workpiece from a sheet of metal arranged on a support of a laser cutting machine (see for example DE102017213394A1, which forms the basis for the preamble).

[0002] Laser cutting processes, in which workpieces are cut from a sheet of metal, are generally known. The sheet of metal is typically placed on a support surface of a laser cutting machine for cutting out the workpieces. This support surface often has spaced-apart ribs, meaning the sheet of metal is not supported across its entire surface. Therefore, there is a risk that smaller workpieces, in particular, will tilt after cutting. This can prevent the workpieces from being removed automatically or cause them to become jammed in the remaining material of the sheet.

[0003] From US patent 2018 / 0093348 A1, it is known to partially cut out workpieces so that they remain connected to a residual grid unit. The residual grid unit is completely separated from the sheet metal so that the residual grid unit, along with the component(s) connected to it, can be removed. To maintain the connection between the respective workpiece and the residual grid unit, the laser beam is interrupted. The sheet metal is therefore not irradiated or processed by the laser beam in the area of ​​the connections.

[0004] The joints obtained using the method described in US 2018 / 0093348 A1 extend across the entire thickness of the sheet metal. Such joints are also referred to as "microjoints." Due to the joints' height, which spans the entire thickness of the sheet metal, separating the workpieces from the respective remaining grid unit is complex. Furthermore, after the laser beam is interrupted to create the joints, the sheet metal must be pierced again. This is time-consuming. Moreover, piercing directly at the workpiece typically results in locally reduced edge quality. Therefore, piercing directly at the workpiece is often not permissible. Object of the invention

[0005] It is an object of the invention to provide a method by which high-quality sheet metal workpieces can be manufactured efficiently, in particular in a reliably automatable and simple process. Description of the invention

[0006] This problem is solved according to the invention by a method having the features specified in claim 1. The dependent claims and the description specify advantageous method variants.

[0007] According to the invention, a method is provided for cutting out at least one workpiece from a sheet of metal. The sheet of metal is typically made of metal. In particular, the sheet of metal can be made of steel. The thickness of the sheet of metal can be at least 2 mm, in particular at least 4 mm. The thickness of the sheet of metal can be at most 40 mm, in particular at most 30 mm.

[0008] The process includes the following steps: A) Arranging a sheet metal panel on a support of a laser cutting machine; B) Directing a laser beam onto the sheet metal panel along an outline of the workpiece, wherein the sheet metal panel is cut through in a principal region of the outline and wherein at least one connection remains in at least one connection region of the outline between the workpiece and an adjacent part of the sheet metal panel, which has a height that is less than the thickness of the sheet metal panel; C) Removing the at least one workpiece and the adjacent part connected thereto from the support, wherein a removal device is used; D) Separating the workpiece from the adjacent part, wherein the separation takes place while the removal device used for removal in step C) holds the workpiece (12) directly or indirectly.

[0009] Steps A) to D) are generally carried out in the specified order.

[0010] In step A), the sheet metal is placed on the support of the laser cutting machine. The sheet metal can be fixed to the support. The support typically has discrete support elements, for example, parallel and spaced-apart ribs, for locally limited support of the sheet metal.

[0011] In step B), a laser beam is directed at the sheet metal. The laser beam can be emitted from a processing head of the laser cutting machine. The point of impact of the laser beam on the sheet metal is moved along an outline of the workpiece. For this purpose, the processing head can be moved relative to the support. A cutting gas jet, for example, nitrogen and / or oxygen, can be directed along the outline of the sheet metal along with the laser beam. The laser beam and the cutting gas jet can exit together from a cutting gas nozzle of the processing head. The outline corresponds to the outer contour of the workpiece. The movement along the outline can be continuous (without interruptions) or in several temporally separated segments. The laser beam is not switched off during the movement along the outline. Material is removed at each point along the outline.

[0012] In a major region of the outline, the sheet metal is cut through. This major region typically comprises more than 90%, preferably more than 95%, and particularly preferably more than 98% of the outline's length. In at least one connection region of the outline, at least one connection remains between the workpiece and an adjacent part of the sheet metal, having a height less than the thickness of the sheet metal. Such a connection is hereinafter also referred to as a "nanojoint" or a "low-height connection." The connection is generally formed on the side of the sheet metal facing away from the laser beam's point of impact. In other words, the at least one workpiece remains connected to at least one other workpiece or a residual grid portion, with the connection not extending over the entire thickness of the sheet metal or the workpiece.The connection to the adjacent part prevents the workpiece from tilting.

[0013] Preferably, the laser power is reduced in the joining area of ​​the outline to obtain the low-profile joint. Alternatively or additionally, the cutting speed can be increased, or the distance between a cutting gas nozzle, through which the laser beam and a cutting gas jet are directed onto the sheet metal or workpiece, can be increased. These parameter changes prevent complete severance of the sheet metal in a localized area. The implementation of the parameter change(s) to generate the low-profile joint can be carried out as described in WO 2019 / 025327 A2. In this respect, reference is made to the description in WO 2019 / 025327 A2, whereby the joints referred to here as low-profile joints or "nanojoints" are referred to as "microjoints" in WO 2019 / 025327 A2.

[0014] According to the invention, in step C), the at least one workpiece, together with the adjacent part connected to the workpiece via at least one low-profile connection, is removed from the support by means of a removal device. Due to the connection between the at least one workpiece and the adjacent part, this can be done particularly easily. A removal device does not need to grip each workpiece, but only one or, if necessary, several suitable points of the assembly, whereby the number of gripping points is typically smaller than the number of workpieces to be removed together. This speeds up the removal process. The removal device can comprise a vacuum gripper, a magnetic gripper, a Bernoulli gripper, and / or a mechanical gripper, in particular a tong gripper.The nanojoints ensure that the workpieces are held firmly enough to each other or within the residual grid part, while still being easily separated from each other or from the residual grid part, for example manually.

[0015] Then, in step D), at least one workpiece is separated from the adjacent part. This separation occurs while the removal device used in step C) holds the workpiece, either directly or indirectly. In other words, the workpieces are separated. Due to the low height of the connection, separation is particularly easy and requires minimal effort. Furthermore, the low height of the connection results in a largely unaffected edge on the separated workpiece, meaning a high-quality workpiece. Separation can be performed manually, for example, by pressing with the fingers or tapping with a hammer. Preferably, separation is automated. If several workpieces were removed together, they can be separated in a single operation, further accelerating the process.Separation can be achieved by shaking, pressing, blowing, or pulling, in particular magnetic pulling or pulling using a vacuum. Shaking, in this context, refers specifically to a repetitive back-and-forth motion. During shaking, at least one impulse can be introduced into the composite material.

[0016] A separating device for separating the workpiece from the part connected to it via the nanojoint can be designed on the removal device, in particular integrated into the removal device. Alternatively, the removal device and the separating device can be provided separately. The separating device can, for example, be an ejector with an ejector pin that is movable, in particular by a pneumatic cylinder. A separate separating device is not necessarily required for separation by vibration. The assembly held together by the low-profile connections can, for example, be shaken by the removal device so that at least one workpiece detaches from the adjacent part. The nanojoints break open in the process.

[0017] For singulation, the removal device, carrying the workpiece assembly, can move over a finished part tray. After singulation, the good parts are located on or in the finished part tray. Any remaining grid component can be placed on a separate tray.

[0018] The inventive method also has the advantage that the cutting gap in which the nanojoint is arranged can be very narrow. This is particularly advantageous when several workpieces share common cutting edges and are to be held together as a composite on the support by their connections (to prevent the individual parts from tilting). In contrast, when creating microjoints (which extend over the entire thickness of the sheet metal or workpiece), the laser beam must be switched off. Subsequent cutting between the workpieces would then require a piercing directly at these workpieces, which is generally not feasible.The narrow kerf also offers the advantage that a vacuum gripper of a removal device does not necessarily have to engage either in a residual grid area without cut lines or on a sufficiently large workpiece, but could extend across the kerf without the suction effect becoming insufficient. In this way, it is not always necessary to provide special areas for gripper positioning.

[0019] The height of a low-profile joint can be at most one-third, preferably at most one-quarter, and particularly preferably at most one-sixth of the thickness of the sheet metal. Typically, the height of the joint is at least one-twentieth, and in particular at least one-tenth, of the thickness of the sheet metal. The length of the low-profile joint, measured along its outline, can be at most half and / or at least one-eighth, and in particular at least one-quarter, of the thickness of the sheet metal. With a joint dimensioned in this way, the workpiece can be securely held and easily separated.

[0020] In an advantageous variant of the process, step B) involves forming a group of workpieces connected to each other via low-profile joints along at least one common outline. In other words, the workpieces share common cutting edges, with at least one nanojoint arranged in each common cutting edge. Such a group of workpieces can also be referred to as a "nest." This variant takes advantage of the fact that no further piercing is required after creating the low-profile joint. The joint can therefore be formed between two workpieces (good parts). Furthermore, the common outline allows for a particularly space-saving arrangement of the workpieces on the sheet metal.

[0021] The group of workpieces can have a circumferential outer outline formed by the outlines of the workpieces along which the sheet metal is cut. In other words, the outer outline can be formed by the main areas of the outlines of the several workpieces. This creates a "nest" of interconnected workpieces, which is completely cut free of the remaining grid. The group of workpieces (the nest) can then be removed from the sheet metal as a single unit—that is, without any remaining grid material acting as ballast.

[0022] In step C), a removal device can engage one of the workpieces in the group. Since the load-bearing capacity of a removal device is limited, more workpieces (good parts) can be removed together in one step. The maximum part weight for the nest is preferably 100 kg. The maximum size of the nest can be 1000 mm x 1500 mm.

[0023] In step B), in addition to the at least one workpiece, at least one sheet metal part can be cut from the sheet metal sheet, which in step C) is removed individually, independently of the at least one workpiece and its adjacent part. This allows for flexible use of the sheet metal sheet, particularly for producing large sheet metal parts that do not need to be fixed and can be handled individually, as well as smaller or elongated workpieces that need to be fixed and are expediently removed as a unit.

[0024] In an advantageous variant of the process, in step B) a group of workpieces is formed, each of which remains connected to a common residual grid section via at least one low-profile connection. In step C), the multiple workpieces and the adjacent residual grid section can be removed together. This variant is particularly suitable for small workpieces that cannot be arranged directly adjacent to one another.

[0025] Preferably, the residual grid component is cut free from the sheet metal sheet before step C), particularly along a circumferential contour. If the residual grid component is located at the edge of the sheet metal sheet, the contour for cutting it free can extend between the edge points of the sheet metal sheet. The contour can be concave. In this way, several (especially smaller and / or slender) workpieces, which remain connected to the residual grid component by nanojoints, can be distributed between larger workpieces or sheet metal parts that do not require stabilization by nanojoints on the sheet metal sheet and surrounded by a continuous cutting line along the contour. The shape of the contour surrounding the multiple workpieces of the group can be chosen essentially freely. In particular, non-square and especially also non-rectangular residual grid components can be separated from the remaining sheet metal sheet. In this way, material-efficient nesting of the workpieces is possible.The arrangement of the smaller workpieces can be determined by the available space on the sheet metal between the larger pieces. The contour around the group of workpieces is then chosen accordingly. In other words, a residual grid section is formed around the workpieces; this section can have any shape and, in particular, does not have to be rectangular. This residual grid section is cut from the sheet metal and removed together with the workpieces it contains.

[0026] The minimum distance between the contour and the workpieces of the group can be at least 12 mm. Preferably, the minimum distance is greater than the thickness of the sheet metal, particularly if the thickness of the sheet metal is more than 15 mm. This prevents the remaining grid part from warping due to the heat input from laser cutting.

[0027] The remaining grid section can have gripping surfaces for a removal device, particularly for vacuum grippers. No cutting lines are generally incorporated into these gripping surfaces. Preferably, at least one gripping surface for a removal device with a diameter of at least 120 mm remains free of workpieces on the remaining grid section. This enables safe handling even of larger assemblies.

[0028] In step C), a removal device can engage the remaining grid section. This simplifies removal of very small workpieces. Furthermore, it prevents damage to the workpieces by the removal device. If the workpieces are separated from the remaining grid section while a removal device is engaged, the weight held by the removal device can be measured to determine whether all workpieces have been removed from the remaining grid section.

[0029] Preferably, the residual grid component is no smaller than 30 mm x 80 mm and no larger than 1000 mm x 1500 mm. A residual grid component of this size can be easily removed by an automated removal device. The maximum weight of the residual grid component, including any workpieces attached to it, is preferably no more than 100 kg.

[0030] The residual grid component, containing the workpieces connected to it via nanojoints, can be positioned at the edge of the sheet metal panel. This allows the edge of the sheet metal panel, which typically remains unused (a typical edge width of 10 mm), to be used both to fix the workpieces for removal and as a point of attachment for a removal device.

[0031] If a removal device engages the workpieces to extract the composite, then at least two nanojoints should be attached to these workpieces opposite each other. This distributes the weight of the composite to be removed across at least two nanojoints, reducing the risk of premature breakage.

[0032] The point(s) of engagement of the removal device are preferably positioned so that the assembly to be removed cannot tilt during removal. The point of engagement can be located at the assembly's center of gravity. In this case, one gripper is generally sufficient. Two points of engagement can be located at opposite corners of the assembly or on opposite sides of an axis passing through the assembly's center of gravity. In these cases, at least two grippers are necessary.

[0033] The support for the sheet metal panel can have parallel ribs. In this case, a workpiece narrower than the distance between two adjacent ribs of the support receives at least two low-profile connections if one narrow side of the workpiece is oriented perpendicular to the ribs. In other words, two nanojoints are provided if the long side of the workpiece runs (approximately) parallel to the ribs. The workpiece is typically at least 100 mm long. The at least two nanojoints stabilize the slender workpiece if it is cut out in a position prone to tipping. Preferably, a first low-profile connection is arranged on a narrow side of the workpiece. Particularly preferably, a second low-profile connection is arranged on a long side of the workpiece, especially at least 60% of the workpiece's length away from the first connection.This effectively stabilizes the workpiece. In particular, it prevents the workpiece from sagging, which could make removal difficult or impossible.

[0034] According to the invention, separation takes place in step D), while a removal device used for removal in step C) holds the workpiece directly or indirectly. This can reduce the equipment required for singulating the workpieces. In particular, additional devices for separating the workpiece from the adjacent part can be dispensed with if the removal device vibrates the connection with the workpiece to separate it. Ejection ("pinning out") of the workpiece can also be carried out simply while the removal device holds the connection with the workpiece. A movable ejector pin can be arranged on the removal device, in particular on a gripper of the removal device.

[0035] Further features and advantages of the invention will become apparent from the claims, the description, and the drawings. According to the invention, the aforementioned features and those described in more detail can each be used individually or in any suitable combination. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples illustrating the invention. Detailed description of the invention and drawing

[0036] The invention is illustrated in the drawing and described with reference to exemplary embodiments. The drawing shows: Fig. 1 a laser cutting machine set up to carry out the laser cutting process according to the invention; Figs. 2a, 2 a workpiece laser-cut from a sheet metal plate, which is held by nanojoints on an adjacent part, in a top view ( Fig. 2a ) and in a section view ( Fig. 2b) corresponding to Ilb-Ilb in Fig. 2aFig. 3 shows a sheet metal panel with four groups of workpieces, each connected to a common residual lattice part of the group via a nanojoint, during a method according to the invention, in a schematic top view; Fig. 4 shows a sheet metal panel with two groups of workpieces, each connected to a common residual part of the group via a nanojoint, and with further individual cut-out sheet metal parts, during a method according to the invention, in a schematic top view; Fig. 5 shows another sheet metal panel with two groups of workpieces, each connected to a common residual part of the group via a nanojoint, and with further individual cut-out sheet metal parts, during a method according to the invention, in a schematic top view; Fig. 6 shows a sheet metal panel with a group of workpieces connected to each other via nanojoints, during a method according to the invention, in a schematic top view; Fig.7. A schematic flowchart of a method according to the invention.

[0037] The in Figure 1 Laser cutting machine shown in perspective 1 For example, it features a CCV laser, diode laser or solid-state laser as a laser beam generator. 2, a movable (laser) processing head 3 and a print run 4 a laser beam is generated in laser beam generator 2. 5 generated, which is guided from the laser beam generator 2 to the processing head 3 by means of a (not shown) fiber optic cable or (not shown) deflecting mirrors. A sheet metal plate is mounted on the support 4. 6 The laser beam 5 is directed onto the sheet metal 6 by means of a focusing optic arranged in the processing head 3. The laser cutting machine 1 is also supplied with cutting gases. 7,For example, oxygen and nitrogen are supplied. The choice of cutting gas 7 depends on the material of the sheet metal 6 and on the quality requirements for the cut edges. Furthermore, an extraction system is required. 8 available, equipped with a suction duct 9, which is located under support 4. The cutting gas 7 is supplied to a cutting gas nozzle. 10 fed to the processing head 3, from which it emerges together with the laser beam 5.

[0038] During laser cutting, the sheet metal panel 6 is cut along a desired path curve. K,The outline of a workpiece to be cut out is cut by means of a laser beam 5 with a higher laser power (cutting power) sufficient to cut through the sheet metal, whereby in this case the laser beam 5, or alternatively or additionally the sheet metal 6, is moved. For this purpose, a point must first be set on or next to the path K to be cut. S to be pierced into the sheet metal plate 6, as shown in Figure 2a shown.

[0039] As in the Figures 2a, 2b The laser cutting of the sheet metal panel 6 takes place in a cutting gap. 11 between a laser-cut workpiece 12 and an adjacent part 13 the sheet metal panel 6 connections 14a, 14bThe workpiece 12 is left in the form of bridges or nanojoints, which fix it to the adjacent part 13 and thus prevent it from tilting relative to the adjacent part 13 or the support 4. Furthermore, the connections 14a and 14b allow the workpiece 12 and the adjacent part 13 to be handled together.

[0040] As in Fig. 2b As shown, the nanojoint 14a, 14b does not extend over the entire thickness. D the sheet metal panel 6, but only in the lower third, therefore it has a lower height d than the thickness D. Therefore, the nanojoint is also referred to here as a connection 14a, 14b of small height. One length L The length of the nanojoint 14a, 14b along the cutting gap 11 is smaller than the thickness D; preferably the length L of the nanojoint 14a, 14b is less than half the thickness D.

[0041] The Nanojoint 14a is located in Figure 2aThe nanojoint 14a is generated at the end of the intersection, shortly before the starting point S of the closed trajectory K is reached again. Nanojoint 14b, on the other hand, is not located at the end of the intersection, but at an arbitrary part of the trajectory K. The length region of the trajectory K in which nanojoints 14a and 14b are formed is also referred to here as a connecting region of the outline. 19 of the workpiece 12. The length of the path curve K in which the sheet metal plate 6 is completely intersected is also referred to as a main area of ​​the outline of the workpiece 12.

[0042] The following describes the creation of the connections 14a, 14b using the example of varying the laser power. In this variant of the method, the nanojoints 14a, 14b are generated solely by selectively adjusting the laser power during the cutting process using appropriately chosen power gradients, which are derived from a Fig. 1 shown control 15The laser cutting machine 1 is preset depending on the workpiece material. The control 15 also controls the movement of the processing head 3 relative to the sheet metal 6. Due to the reduced laser power, the cutting process no longer has the linear energy required for a complete cut available, so the material is not melted across the entire thickness D of the sheet metal 6 and a nanojoint 14a, 14b remains in the lower area of ​​the cutting gap 11 or the cutting edge between the laser-cut workpiece 12 and the adjacent part 13.

[0043] Except for the laser power, all other cutting parameters of the laser cutting process remain unchanged during the creation of the nanojoint 14a, 14b, e.g., the focus position of the laser beam 5, the distance of the cutting gas nozzle 10 to the workpiece surface, the cutting gas pressure, and the cutting speed. After the creation of the nanojoint 14b, cutting continues with the standard parameters. After the creation of the nanojoint 14a, the laser beam 5 can be switched off. Alternatively, another workpiece can be cut.

[0044] To create the nanojoint 14b, which is not located at the end of the path K and has a lower height d than the workpiece thickness D, the laser power of the laser beam 5 is reduced during laser cutting of the sheet metal 6. This reduction occurs on a segment of the path K corresponding to the length L of the nanojoint 14. The laser power is reduced from a higher laser power (cutting power), sufficient to cut through the sheet metal 6, to a lower laser power (countersinking power), insufficient to completely cut through the sheet metal 6. The laser power is then increased again to the higher laser power (cutting power). During processing with the lower laser power (countersinking power), a depression is created in the sheet metal 6 above the nanojoints 14a and 14b.

[0045] Figure 3 shows a metal panel 6, from which four groups 16 from workpieces 12. Each group 16 comprises a plurality of workpieces 12 and a residual grid part. 17,which represents an adjacent part 13 for the workpieces of group 16. All workpieces 12 of a group 16 can be identical. Alternatively, a group 16 can contain different workpieces 12. The workpieces 12 of a group 16 are each connected to the associated residual lattice part 17 via at least one nanojoint 14 (abstractly indicated by a checkerboard pattern). It is understood that the connections 14 are made smaller in practice than schematically sketched here for reasons of visibility. The residual lattice parts 17 are each connected along a circumferential contour. 18 Cut from sheet metal 6. The remaining grid parts 17 are shown here as rectangular examples.

[0046] The workpieces 12 can be within their respective outlines 19 cut inner contours 20exhibit. It is conceivable, in sufficiently large areas encompassed by the inner contours 20, to cut out further, smaller workpieces within the inner contours 19 and to connect them to the workpieces 12 via nanojoints (not shown in detail).

[0047] Attack surfaces can be found on the remaining grid parts 17. 21 The gripping surfaces 21 are intended for use with grippers of a removal device (not shown in detail). The gripping surfaces 21 can, for example, have a diameter of more than 120 mm. In this case, the gripping surfaces 21 are arranged in the corners of the residual grid parts 17. No cutting lines are provided within the gripping surfaces 21. Vacuum grippers can therefore suction the residual grid parts 17 in the area of ​​the gripping surfaces 21. The respective residual grid part 17, together with the workpieces 12 held to it, can then be removed from the remaining residual part. 30 taken from sheet metal panel 6.

[0048] To separate the workpieces 12, the removal device can shake or vibrate (jerk back and forth) the respective residual grid section 17. Due to the dynamic loads generated, the connections 14 break. The workpieces 12 fall out of the residual grid section 17 and can be collected, for example, in a collection container. The weight loss during the removal of the workpieces 12 can be measured by the removal device, allowing the completeness of the separation process to be verified.

[0049] Figure 4 shows a sheet metal panel 6, from which several larger sheet metal parts are made. 22 as well as two groups 16, each consisting of several smaller workpieces 12, were cut out. The sheet metal parts 22 are each completely cut out and are removed individually. The workpieces 12 of the two groups 16 are connected via in Figure 4 Nanojoints not shown in detail, each with a residual lattice part 17a, 17bconnected (compare the above description to Figure 3 ). The residual grid parts 17a, 17b can in turn have attack surfaces 21 for grippers of a removal device.

[0050] A circumferential contour 18 of the in Figure 4 The residual grid section 17a, located at the bottom right, is rectangular. Two attack surfaces 21 can be provided in opposite corners.

[0051] The in Figure 4 The left residual lattice part 17b has a complex contour 18. Here, the residual lattice part 17b is approximately C-shaped and has a concave section. Attack surfaces 21 can be provided in the area of ​​the ends of the three legs of the C-shape.

[0052] The arrangement of the workpieces 12, which are connected to the respective residual grid parts 17a, 17b via nanojoints in the groups 16, is chosen such that the surface of the sheet metal panel 6 is utilized as extensively as possible for the production of the sheet metal parts 22 and the workpieces 12. The circumferential contours 18 of the residual grid parts 17a, 17b were chosen so that the workpieces 12 are expediently grouped together in the groups 16.

[0053] Figure 5 shows a sheet metal panel 6, which is mounted on parallel ribs. 23 a print run of 4 from a laser cutting machine 1 (compare Figure 1 ) rests on. Two larger sheet metal parts 22 are completely cut out. Furthermore, two groups 16 of several workpieces 12 are shown here as examples.

[0054] The in Figure 5 The group 16 shown at the bottom left includes, by way of example, two small workpieces 12, each connected via a nanojoint 14 to a residual lattice part. 17care connected. The residual grid part 17c is arranged directly at the edge of the sheet metal panel 6. A contour 18 of the residual grid part 17c extends between two outer surfaces of the sheet metal panel 6. The area of ​​the residual grid part 17c adjacent to the edge can be used as a contact surface for handling the assembly of the two workpieces 12 and the residual grid part 17c.

[0055] The in Figure 5 The group 16 shown to the right of center includes, by way of example, two slender (elongated) workpieces 12, each connected to a residual lattice part via two nanojoints 14. 17d are connected. Narrow sides 24 of the two workpieces 12 are shorter than a distance A between adjacent footbridges 23 of edition 6. Although long sides 25Since the two workpieces 12 are longer than the distance A, the slender workpieces 12 could tip or fall between the webs 23 in the present orientation with their longitudinal sides 25 parallel to the webs 23. To prevent this, they are fixed to the residual grid part 17d by the nanojoints 14. One of the nanojoints 14 is arranged on a narrow side 24. The second of the nanojoints 14 is arranged on a long side 25. A distance E The distance between the two nanojoints of a respective workpiece 12 can be at least two-thirds the length of the workpiece.

[0056] Attack surfaces 21 for grippers of a removal device can be provided on the residual grid part 17d. If the cutting gap along the outline 19 of the workpieces 12 is sufficiently narrow, it is also conceivable that attack points 21 extend both on one of the workpieces 12 and on the adjacent residual grid part 17d.

[0057] Figure 6 shows a metal panel 6 with a group 26 of workpieces 12 connected to each other via nanojoints. Adjacent workpieces 12 share common outlines here. 27 Along one of the common outline lines 27, at least two of the workpieces 12 abut each other. The outline of each of the workpieces contains at least one of the common

[0058] Outline 27. Main areas of the common outline 27 are severed when the workpieces 12 are cut out. Nanojoints 14 remain in the connection areas of the common outline 27. The workpieces 12 are held together by the nanojoints 14. The connection of the directly joined workpieces 12 is also referred to here as a nest.

[0059] Group 26 of workpieces 12 has a total circumferential outer outline. 28 The outer outline 28 is defined by free outline lines. 29The workpieces 12 are formed. No further workpieces 12 of group 26 border the free outline lines 29. The free outline lines 29 are part of the outline of the workpieces 12 arranged on the outside of the nest.

[0060] The sheet metal panel 6 is completely cut through along the outer outline 28. The group 26 can therefore be made from a remaining part. 30 the sheet metal panel 6 can be removed. Grippers of a removal device can directly engage one or more of the workpieces 12 for this purpose. Figure 6 Three attack surfaces 21 for vacuum grippers, lying approximately on a diagonal through the group 26, are marked as examples.

[0061] Figure 7 The diagram shows a summary flowchart of a process for cutting out at least one workpiece, preferably several workpieces, from a sheet of metal. In one step 102 The sheet metal is placed on a support of a laser cutting machine.

[0062] Then, in one step 104 Laser processing is used. For this purpose, a laser beam is directed at the sheet metal. An impact point of the laser beam is moved along the outline of at least one workpiece. In a major region of the outline of each workpiece, the sheet metal is completely cut through. In at least one connection region of the outline of each workpiece, the laser processing is controlled such that a connection remains between the workpiece and an adjacent part of the sheet metal. This connection has a height that is less than the thickness of the sheet metal. To create the connection with a low height (the so-called nanojoint), the laser power can be reduced. The adjacent part can be another workpiece or a residual grid component.

[0063] In a subsequent step 106The assembly of at least one workpiece and the adjacent part is removed from the support by means of a removal device. A group of workpieces, which may include a residual grid section, may have previously been cut free from a residual part of the sheet metal in step 104.

[0064] Finally, in one step 108 at least one workpiece is separated from the adjacent part, with the separation taking place while the workpiece is being removed in the step 106 The removal device used holds the workpiece directly or indirectly. In particular, all workpieces of the assembly are separated from each other and from any remaining grid component that may be present. Reference symbol list

[0065] laser cutting machine 1 Laser beam generator 2 Processing head 3 Edition 4 laser beam 5 Sheet metal panel 6 Cutting gases 7 extraction system8 extraction duct 9 Cutting gas nozzle 10 Cut gap 11 workpiece 12 adjacent part 13 Connections (nanojoints) 14; 14a, 14b steering 15 group 16 with workpieces 12 and residual grid part residual grid part 17; 17a, 17b; 17c, 17d contour 18 outline of a remaining grid section 19 inner contour 20 Attack surfaces 21 Sheet metal parts 22 footbridges 23 Narrow sides 24 long sides 25 group 26 of interconnected workpieces 12 common outlines 27 Outer outline 28 free outlines 29 Remaining part 30 trajectory curve K Insertion point S thickness D the sheet metal panel 6 height d of the connections 14; 14a, 14b length L of connections 14; 14a, 14b distance A between footbridges 23 distance E Arrange 102Laser processing 104 Remove 106 Separate 108

Claims

1. Method for cutting at least one workpiece (12) from a metal sheet (6), comprising the steps of A) arranging a metal sheet (6) on a support (4) of a laser cutting machine (1); B) directing a laser beam (5) onto the metal sheet (6) along an outline (19) of the workpiece (12), wherein the metal sheet (6) is cut through in a main region of the outline (19), and wherein at least one connecting portion (14; 14a, 14b), which has a height (d) that is less than a thickness (D) of the metal sheet (6), remains in at least one connection region of the outline (19) between the workpiece (12) and an adjoining part (13) of the metal sheet (6); characterized by the following steps: C) removing the at least one workpiece (12) and the adjoining part (13) connected thereto from the support, wherein a removal device is used; D) separating the at least one workpiece (12) from the adjoining part (13), wherein the separation takes place while the removal device used for removal in step C) indirectly or directly holds the workpiece (12).

2. Method according to claim 1, characterized in that a height (d) of the connecting portion (14; 14a, 14b) of low height is at most one third, preferably at most one quarter, and particularly preferably at most one sixth of the thickness (D) of the metal sheet (6).

3. Method according to any of the preceding claims, characterized in that a length (L) of the connecting portion (14; 14a, 14b) of low height, measured along the outline (19), is at most half and / or at least one quarter of the thickness (D) of the metal sheet (6).

4. Method according to any of the preceding claims, characterized in that, in step B), a group (26) of workpieces (12) is formed which are connected to one another by means of connecting portions (14) of low height at at least one common outline line (27) of the workpieces (12).

5. Method according to claim 4, characterized in that the group (26) of workpieces (12) has a circumferential outer contour (28), which is formed by outline lines (29) of the workpieces (12), along which the metal sheet (6) is cut through.

6. Method according to claim 4 or 5, characterized in that, in step C), a removal device engages one of the workpieces (12) of the group (26).

7. Method according to one of the claims 1 to 3, characterized in that, in step B), a group (16) of workpieces (12) is formed which each remain connected to a common sheet skeleton part (17; 17a, 17b; 17c, 17d) via at least one connecting portion (14) of low height, and in that, in step C), the plurality of workpieces (12) and the adjoining sheet skeleton part (17; 17a, 17b; 17c, 17d) are removed jointly.

8. Method according to claim 7, characterized in that the sheet skeleton part (17; 17a, 17b; 17c, 17d) is cut free from the metal sheet (6) prior to step C) - in particular, along a circumferential contour (18) - wherein the contour (18) is preferably concave.

9. Method according to claim 8, characterized in that a smallest distance of the contour (18) from the workpieces (12) of the group (16) is at least 12 mm, and preferably is greater than the thickness (D) of the metal sheet (6), and / or that, on the sheet skeleton part (17; 17a, 17b; 17c, 17d), at least one engagement surface (21) for a removal device of at least 120 mm in diameter remains free of workpieces (12).

10. Method according to any of claims 7 to 9, characterized in that, in step C), a removal device engages the sheet skeleton part (17; 17a, 17b; 17c, 17d).

11. Method according to any of the preceding claims, characterized in that the support (4) has webs (23) running in parallel, and in that the workpiece (12), which is narrower than a spacing (A) between two adjacent webs (23), receives two connecting portions (14) of low height - preferably wherein a first of the connecting portions (14) of low height is arranged on a narrow side (24) of the workpiece (12), and particularly preferably wherein a second of the connecting portions (14) of low height is arranged on a long side (25) of the workpiece (12) - in particular, distanced by at least 60% of a length of the workpiece (12) from the first connecting portion (14).

12. Method according to any of the preceding claims, characterized in that the removal device for removal in step C) has a vacuum gripper, a magnet gripper, a Bernoulli gripper, and / or a mechanical gripper - in particular, a tongs gripper.

13. Method according to any of the preceding claims, characterized in that the separation in step D) takes place by vibrating, pressing, blowing out, or pulling - in particular, magnetic pulling or pulling by means of a negative pressure.