METHOD FOR LASER CUTTING PLATE-SHAPED WORKPIECES AND ASSOCIATED COMPUTER PROGRAM PRODUCT

Description

[0001] The invention relates to a method for removing a laser-cut workpiece part. The workpiece part can, for example, be cut by a laser cutting method, particularly of a plate-shaped workpiece, along a path curve using a laser beam, wherein, in order to create a microjoint with a lower height than the workpiece thickness, the laser power of the laser beam is reduced on a segment of the path curve corresponding to the length of the microjoint from a higher laser power sufficient to cut through the workpiece to a lower laser power insufficient to completely cut through the workpiece.

[0002] One such laser cutting process has become known, for example, through JPH06190576A.

[0003] When laser cutting sheet-shaped workpieces, it is crucial that the slag produced during cutting can escape freely downwards from the kerf. To ensure this, the workpiece support in laser cutting machines for sheet-shaped workpieces typically consists of several support strips inserted into a frame. These support strips have a serrated shape, resulting in only point contact with the workpiece. Depending on the size and position of a workpiece section on the support strips, the cutting gas pressure during the cutting process can cause the section to tilt. This can cause the workpiece section to wedge itself between the support strips and tilt, potentially leading to a collision between the cutting head or gas nozzle and the workpiece section. Furthermore, the random positioning of the workpiece sections makes automated removal difficult or even impossible.Smaller workpiece parts can fall into the gaps between the support strips if they are in an unfavorable position, and thus onto the slag conveyor belt located under the workpiece support or into slag collection containers.

[0004] To solve this problem, it is known to fix the workpiece parts in the remaining workpiece using so-called microjoints, i.e., connecting ribs remaining in the cutting gap between the workpiece part and the surrounding remaining workpiece, thus preventing tilting. However, the use of microjoints has several disadvantages: Microjoints typically extend across the entire workpiece thickness, making it very difficult or even impossible to remove the workpiece parts from the remaining workpiece by hand when the workpiece is thicker than 5 mm. After the workpiece parts are removed, residues of the microjoints remain on the cut edge and must be removed through time-consuming post-processing. Furthermore, microjoints are typically placed at the end of the cut. If more than one microjoint is required in a workpiece contour, it can only be created by additional piercing and approaching the contour.This reduces the productivity of the cutting process.

[0005] From JP2001334379A, JPH06190576A, JP2004105990A and JPH0788571A, it is already known to use microjoints that do not extend over the entire workpiece thickness, but have a lower height than the workpiece thickness. This is achieved by changing several cutting parameters during the creation of the microjoint compared to the values ​​set during laser cutting of the rest of the contour.

[0006] JP2001334379A discloses a method for creating the microjoint: first, the cutting speed is linearly increased while the laser power and cutting gas pressure are simultaneously reduced. The cutting head is then retracted slightly without cutting, and the laser power is increased to a maximum value greater than the original laser power to re-penetrate the workpiece. Once the gas pressure and laser power have returned to their original values, the remaining contour is cut. However, the numerous process steps increase the complexity of the method and the time required.

[0007] In the aforementioned JPH06190576A, it is disclosed to create a microjoint by abruptly reducing the laser power to a lower value, linearly increasing the cutting speed and abruptly changing the pressure of various gases, and subsequently abruptly increasing the laser power to the original value, linearly reducing the cutting speed to the original value and abruptly changing the pressure of the gases.

[0008] In contrast, the present invention aims to further improve a method for removing a laser-cut workpiece part.

[0009] This problem is achieved according to the invention by a method for the Extraction of a laser-cut workpiece part with the features of claim 1 is solved.

[0010] It was discovered that a local microjoint in the lower part of the workpiece thickness can be reliably generated solely by correctly adjusting either the laser power, the cutting speed, or the distance of the cutting gas nozzle (through which the laser beam is directed at the workpiece) to the workpiece during the cutting process. This involves correctly adjusting a single, selected parameter using appropriately chosen gradients of parameter change. Due to the reduced laser power, the increased cutting speed, or the defocusing of the laser beam caused by the increased distance of the cutting gas nozzle to the workpiece, the cutting process no longer has the linear energy required for a complete cut and / or the momentum of the cutting gas needed to expel the molten metal. As a result, the workpiece is not melted across its entire thickness, so that in the lower part of the kerf, or...A microjoint remains between the laser-cut workpiece section and the rest of the workpiece at the cutting edge. After the microjoint is created, cutting can continue with standard parameters. Alternatively, the microjoint can be positioned at the end of a contour cut, and the laser beam can be switched off at a lower power after the microjoint is created, either when the starting point is reached again in the case of a closed cutting contour or when the cutting contour ends at a workpiece edge.

[0011] Surprisingly, it has been shown that the gradient of the time-dependent decrease and the gradient of the increase of the changed parameter must be different in order to produce a microjoint reproducibly and reliably. This can be explained by the inertia of the cutting process with respect to changes in cutting parameters: The transition from a "good cut" to a "bad cut" when the laser power is reduced, the cutting speed is increased, or the distance between the cutting gas nozzle and the workpiece is increased differs from the transition from a "bad cut" to a "good cut" when the laser power is increased, the cutting speed is reduced, or the distance between the cutting gas nozzle and the workpiece is increased. Furthermore, the gradients of the parameter changes also depend on the cutting speed, how the melt is ejected from the kerf, and what shape (elongated, rounded) a stable microjoint must have.

[0012] Preferably, the power drop from higher to lower laser power is not abrupt, but lasts at least 5 ms, preferably at least 8 ms, preferably at least 10 ms. The same applies in an alternative embodiment to increasing the cutting speed or the distance between the cutting gas nozzle and the workpiece.

[0013] The power drop from higher to lower laser power can, for example, follow an exponentially decreasing curve or, preferably, be linear or nearly linear. Likewise, the power increase from lower to higher laser power can, for example, follow an exponentially increasing curve or, preferably, be linear or nearly linear. The same applies to changes in cutting speed or the distance between the cutting gas nozzle and the workpiece.

[0014] The lower laser power preferably remains constant or nearly constant at a base level over time, but it can also vary over time, for example, increasing linearly after the power drop or continuing to decrease linearly before increasing to the higher laser power. The same applies to the behavior of the increased cutting speed or the increased distance between the cutting gas nozzle and the workpiece.

[0015] In the case of oxygen cutting, where the laser cutting is performed using oxygen as the cutting gas, tests have surprisingly shown that microjoints of reduced thickness can only be reliably produced if the power increase from lower to higher laser power is slower than the power decrease from higher to lower laser power, preferably at least twice as long. Thus, during microjoint production, the power decrease occurs faster than the power increase. For linear decrease and increase curves, it is advantageous that the magnitude of the decrease slope is greater than the magnitude of the increase slope, and that the magnitude of the ratio of decrease slope to increase slope is consistently greater than 1, preferably greater than 2, for all sheet thicknesses.This effect can be explained by the fact that during the transition from a "bad cut" to a "good cut," all process parameters must be optimal at the end of the power increase to form the ideal cutting front; that is, the transition from a "bad cut" to a "good cut" is more demanding. In flame cutting, where the exothermic oxidation reaction also contributes significantly to the cutting process, a long transition time is required until optimal parameters for a "good cut" are re-established. This relationship must be considered analogously when the cutting speed or the distance of the cutting gas nozzle to the workpiece is varied: Reducing the cutting speed or decreasing the distance of the cutting gas nozzle to the workpiece must be slower than increasing it, preferably taking at least twice as long.

[0016] As the experiments further demonstrated, during oxygen flame cutting, the power increase from the lower to the higher laser power should preferably last at least 30 ms, and the period of lower laser power should preferably last at least 20 ms. The lower laser power must be adjusted for different workpiece thicknesses; as the workpiece thickness increases, the lower laser power also increases. Nevertheless, for all workpiece thicknesses, the periods of power decrease, power increase, and lower laser power can be chosen to be of equal or nearly equal length. These values ​​apply analogously to changes in the cutting speed or the distance between the cutting gas nozzle and the workpiece.

[0017] In the case of fusion cutting, where the laser cutting is performed with an inert gas, such as nitrogen, or an inert gas-air mixture (e.g., compressed air) as the cutting gas, tests have surprisingly shown that microjoints of reduced thickness can only be reliably produced if the power increase from lower to higher laser power is faster than the power decrease from higher to lower laser power, preferably at least twice as fast, and particularly preferably at least five times as fast. Thus, when creating the microjoint, the power decrease occurs more slowly than the power increase. The power increase must be faster to achieve an ideal (steeper) cutting front inclination, ensuring that the melt is reliably expelled downwards from the cutting gap.In the case of linear drop and rise curves, the magnitude of the drop slope should advantageously be less than the magnitude of the rise slope, and the magnitude of the ratio of drop slope to rise slope should be less than 1, preferably less than 0.5, and particularly equal to 0.1, for all workpiece thicknesses. The same applies if the cutting speed or the distance of the cutting gas nozzle to the workpiece is varied: The reduction of the cutting speed or the reduction of the distance of the cutting gas nozzle to the workpiece must occur faster than the increase, preferably at least twice as fast, and particularly preferably at least five times as fast.

[0018] As the experiments further demonstrated, during nitrogen melt cutting, the power increase from the lower to the higher laser power should be less than 5 ms, preferably less than 2 ms, and the period of lower laser power should last at least 5 ms, preferably at least 8 ms. Furthermore, the lower laser power should be at least 3 kW and the cutting gas pressure less than 10 bar. For all workpiece thicknesses, the time periods of power decay, power increase, and lower laser power can be chosen to be of equal or nearly equal length. These values ​​also apply when varying the cutting speed or the distance between the cutting gas nozzle and the workpiece.

[0019] The invention relates to a method, known, for example, from DE 10 2014 209 811 A1, for removing a laser-cut, in particular plate-shaped, workpiece part from the remaining workpiece, wherein the workpiece part is held in a tilt-proof manner from one side by a counter-holder, in particular a planar one, and is pushed out of the remaining workpiece from the other side by at least one ejection element (e.g., an ejection pin). According to the invention, the workpiece part is held in the remaining workpiece by at least one microjoint with a height less than the workpiece thickness before removal, and the microjoint is severed during removal. This removal method according to the invention can be applied both to microjoints produced by the laser cutting method described above and to microjoints produced by other means with a height less than the workpiece thickness.

[0020] By stabilizing the laser-cut workpiece from the side opposite the ejection element with the counter-holder and holding it horizontally, the microjoints can be cleanly severed without the workpiece becoming stuck or jammed in the rest of the workpiece. Ejection can be performed from either above or below. The counter-holder can also be used to transport the removed workpiece, for example, if it is designed as a suction device or a lowering conveyor belt. Due to the reduced height of the microjoints, the force required to cut them is not significantly greater than the force required to eject the workpiece from the kerf, thus enabling reliable removal without excessive force.

[0021] The positioning of the ejector element(s) is preferably chosen such that the ejector element or the center of gravity of the area spanned by several ejector elements is offset from the center of gravity of the workpiece part in the direction of the microjoint(s) in order to further increase the process reliability of the removal.

[0022] Further advantages and advantageous embodiments of the subject matter of the invention will become apparent from the description, the claims, and the drawings. Likewise, the features mentioned above and those listed further below can be used individually or in any combination. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples for illustrating the invention.

[0023] They show: Fig. 1 a laser cutting machine suitable for carrying out a laser cutting process; Figs. 2a, 2 a workpiece part laser-cut from a workpiece, which is held in the rest of the workpiece by microjoints, in a top view ( Fig. 2a ) and in a section view ( Fig. 2b ) according to IIb-IIb in Fig. 2a Fig. 3 shows a first power-down clamp for creating a microjoint when laser cutting a workpiece with oxygen as the cutting gas; Fig. 4 shows a second power-down clamp for creating a microjoint when laser cutting a workpiece with nitrogen as the cutting gas; and Figs. 5a-5f show the cutting of a microjoint when pushing out a laser-cut workpiece part, held securely between an ejector element and a counter-holder, from the remaining workpiece.

[0024] The in Fig. 1 Laser cutting machine shown in perspective 1For example, it uses a CO2 laser, diode laser or solid-state laser as a laser beam generator. 2, a movable (laser) processing head 3 and a workpiece support 4 a laser beam is generated in laser beam generator 2. 5 The laser beam is generated and 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 plate-shaped workpiece is placed on the workpiece support 4. 6 The laser beam 5 is directed onto the workpiece 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 depends on the workpiece material and the quality requirements for the cut edges. Furthermore, an extraction system is required. 8 available, equipped with a suction duct9, which is located under the workpiece 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.

[0025] During laser cutting, the workpiece 6 is moved along a desired path. K by means of a laser beam 5 with a higher laser power sufficient to cut through the workpiece 6 PA The cutting process involves moving the laser beam 5, or alternatively or additionally, the workpiece 6. For this to occur, a point must first be set on or next to the path to be cut. S to be inserted into the workpiece, as in Fig. 2a shown.

[0026] As in Figs. 2a, 2b The following are shown: during laser cutting of workpiece 6 in the cutting gap 11 between a laser-cut workpiece part 12 and the remaining workpiece 13Connecting bridges or microjoints 14a, 14b left standing, which fix the workpiece part 12 in the remaining workpiece 13 and thus prevent it from tilting relative to the remaining workpiece 13. As in Fig. 2b As shown, the Microjoint 14 does not extend over the entire workpiece thickness. D, but only in the lower third of the workpiece thickness, thus exhibiting a lower height d The workpiece thickness D is given by the microjoint. Microjoint 14a is located at the end of the cut, meaning it is generated shortly before the starting point S of the closed path K is reached again. Microjoint 14b, on the other hand, is not located at the end of the cut, but at an arbitrary part of the path K.

[0027] The following describes a method using the example of varying laser power. In this implementation of the method, the microjoints 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 unit 15 also controls the movement of the processing head 3 relative to the workpiece 6. Due to the reduced laser power, the cutting process no longer has the linear energy required for a complete cut available, so the workpiece material is not melted across its entire thickness D. As a result, a microjoint 14a, 14b remains in the lower part of the cutting gap 11 or at the cutting edge between the laser-cut workpiece section 6 and the remaining workpiece 13. Except for the laser power, all other laser cutting parameters remain unchanged during the creation of the microjoint 14a, 14b, such as 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 microjoint 14b is created, cutting continues with the standard parameters.After the creation of the microjoint 14a, the laser beam 5 is switched off.

[0028] To generate the microjoint 14b, which is not located at the end of the trajectory K and has a lower height d than the workpiece thickness D, the laser power of the laser beam 5 is directed along one of the lengths during laser cutting of the workpiece 6. L of the microjoint 14 corresponding section of the trajectory from the higher laser power PA sufficient to cut through the workpiece 6 to a lower laser power insufficient to completely cut through the workpiece 6 PS lowered and then increased again to the higher laser power PA.

[0029] Fig. 3 shows the time course of the laser power with a time range 30to generate the microjoint 14b during so-called oxygen cutting, i.e., laser cutting of the workpiece 6 using oxygen as the process gas 7. During oxygen cutting, the workpiece material is melted and largely oxidized. In the illustrated embodiment, the oxygen cutting was performed on a structural steel workpiece 6 with a workpiece thickness D of 5 mm and a laser power PA of more than 3000 W.

[0030] The time period 30 is divided into three time periods I-III: I (t1 to t2): linear power reduction -ΔP from the higher laser power PA (3.5 kW) to the lower laser power PS within approximately 15 ms, II (t2 to t3): Maintaining the lower laser power (base power) PS for approximately 25 ms, and III (t3 to t4) linear performance increase +ΔP from the lower laser power PS to the higher laser power PA within approximately 40 ms.

[0031] When generating microjoint 14b by oxygen cutting, the power increase +ΔP from the lower to the higher laser power in time interval III is slower than the power decrease -ΔP from the higher to the lower laser power in time interval I; in the illustrated embodiment, it is even more than twice as slow. The power decrease -ΔP in time interval I and the power increase +ΔP in time interval III are both linear or nearly linear, with the magnitude of the gradient dP / dt in time interval I being greater than the magnitude of the gradient dP / dt in time interval III. The magnitude of the gradient ratio is greater than 2 and is approximately 2.67 in the illustrated embodiment. When generating microjoint 14a, the power decrease -ΔP in time interval I and the maintenance of the lower laser power PS in time interval II proceed analogously. At the end of time interval II, the laser beam is switched off, and the cutting process is complete.The time t1 at which the power drop -ΔP begins is chosen such that the starting point of the trajectory K is reached again at the end of the time interval II.

[0032] The level of the lower laser power (base power) PS must be adjusted to different workpiece thicknesses D; as the workpiece thickness D increases, the base power PS also increases in the range between 100 W and 3000 W.

[0033] Time intervals I-III can be chosen to be of equal length for all workpiece thicknesses D. The base power PS should be maintained for at least 25 ms to ensure that the generated microjoint 14a, 14b has sufficient strength. The magnitude of the ratio of the drop-down to the rise gradient is greater than 1 for all sheet thicknesses D, preferably greater than 2, and is in particular approximately 2.67.

[0034] Fig. 4 shows the time course of the laser power with a time range 40To generate the microjoint 14b, which is not located at the end of the path K, during so-called fusion cutting, i.e., during laser cutting of the workpiece 6 using an inert gas or an inert gas-oxygen mixture, e.g., nitrogen, as the cutting gas 7. In fusion cutting, the workpiece material is simply melted. The resulting molten material is then blown out and extracted together with the cutting gas 7 via the extraction duct 9 through the extraction device 8. For fusion cutting, a power of 8 kW is required for the same workpiece thickness and material, since the process gas does not contribute any process energy and the cutting speeds are higher than in flame cutting. In the illustrated embodiment, the nitrogen fusion cutting was also performed on a structural steel workpiece 6 with a workpiece thickness D of 5 mm, but with an output power of 8 kW and a cutting gas pressure of 6 bar.The main difference between oxygen flame cutting and nitrogen melt cutting lies in the higher feed rates of the latter. Therefore, both the power reduction and increase times, as well as the time required to maintain the base power, are significantly shorter than with oxygen flame cutting. Due to these shorter times and the smaller reduction relative to the initial power, the impact on the cutting process is less pronounced. The laser power does not need to be reduced as much relative to the initial power compared to oxygen flame cutting, since the process gas does not contribute energy to the cutting process.

[0035] Investigations during fusion cutting have shown that the reliable generation of microjoints 14a, 14b with a height d less than the workpiece thickness D is only possible with reduced cutting gas pressure, thus indicating that the cutting gas pressure is a crucial factor for the successful generation of a microjoint 14a, 14b during fusion cutting. The cutting gas pressure typically used in fusion cutting, well above 10 bar, does not allow for the reproducible generation of microjoints 14a, 14b. While reducing the laser power can create a connection between the workpiece and the remaining lattice, the height and stability of the generated microjoint 14a, 14b fluctuate significantly even with small variations in laser power of less than 50 W. It has been shown that microjoints 14a, 14b can be reliably generated by varying the power when the cutting gas pressure is below 10 bar.

[0036] Time period 40 is divided into three time periods I-III: I (t1 to t2): linear power reduction -ΔP from the higher laser power PA to the lower laser power PS within approximately 10 ms, II (t2 to t3): Maintaining the lower laser power (base power) PS for approximately 8 ms, and III (t3 to t4) Linear power increase +ΔP from the lower laser power PS to the higher laser power PA within approximately 1 ms.

[0037] When generating the microjoint 14b by nitrogen melting, the power increase +ΔP in time interval III occurs faster than the power decrease -ΔP in time interval I, preferably at least twice as fast, particularly preferably at least 5 times as fast, and in the illustrated embodiment even approximately 10 times as fast. The power decrease -ΔP in time interval I and the power increase +ΔP in time interval III are each linear or nearly linear, with the magnitude of the power gradient dP / dt in time interval I being smaller than the magnitude of the power gradient dP / dt in time interval III. The magnitude of the gradient ratio is less than 1, preferably less than 0.5, and is approximately 0.1 in the illustrated embodiment.

[0038] When generating microjoint 14a, the power decay -ΔP in time interval I and the maintenance of the lower laser power PS in time interval II proceed in the same way as when generating microjoint 14b. At the end of time interval II, however, the laser beam is switched off, and the cut is completed. The time t1, at which the power decay -ΔP begins, is chosen such that the starting point of the trajectory K is reached again at the end of time interval II.

[0039] The individual time intervals I-III are shorter than in oxygen flame cutting because the cutting speed is higher and the cutting gas does not contribute energy. Thus, a sufficiently long and stable microjoint 14a, 14b is formed after a shorter time. The base power PS should be maintained for at least 8 ms to ensure that the resulting microjoint 14a, 14b has sufficient strength. The strength of the microjoint 14a, 14b can be influenced by selecting the base power PS and the duration of time interval II.

[0040] The level of the base power PS can be adjusted to different workpiece thicknesses D, but must be at least 3000 W.

[0041] Time intervals I-III can be chosen to be of equal length for all workpiece thicknesses D. The magnitude of the ratio of the lowering gradient to the rising gradient is less than 1 for all sheet thicknesses D, preferably less than 0.5, and is particularly approximately 0.1.

[0042] This method allows for the reliable production of microjoints 14a, 14b with reduced height d during both oxygen flame cutting and nitrogen melt cutting. These microjoints can be easily separated manually and leave only minimal residue on the cutting edge. Since the cutting speed does not need to be reduced during the formation of the microjoint 14a, 14b, the productivity of the cutting process is maintained. Only one processing parameter needs to be varied to produce short, stable microjoints 14a, 14b that can also be positioned in pathways K with tight radii. Depending on the type of workpiece to be cut, as well as the shape and size of the pathways, it may also be advantageous to use an alternative version of the method, changing not the laser power but the cutting speed or the distance between the cutting gas nozzle 10 and the workpiece 6.

[0043] In the Figs. 5a-5fis the severing of a microjoint 14 during the (sandwich) extrusion of one between several extrusion elements (e.g. extraction pins) 51 and a flat counter-holder designed as a vacuum suction cup 52 shown the laser-cut workpiece part 12 held in a tilt-proof manner from the remaining workpiece 13.

[0044] Fig. 5a Figure 12 shows the laser-cut workpiece part 12, which is still held in the remaining workpiece 13 by several microjoints 14, which have a lower height than the workpiece thickness. Fig. 5b The counter-holder 52 is lowered from above onto the workpiece part 12 and the adjacent edge area of ​​the remaining workpiece 13. The ejector elements 51 move upwards until they are in Fig. 5cthe underside of the workpiece part 12, thus holding the workpiece part 12 securely between the ejection elements 51 and the counter support 52. The ejection elements 51 and the counter support 52 then move upwards synchronously, pushing the workpiece part 12 out of the remaining workpiece 13 and thereby cutting the microjoints 14 ( Fig. 5d ). The suction function of the counter-holder 52 is activated to hold the workpiece part 12 on the counter-holder 52 and to be able to transport it away ( Figs. 5e, 5f ).

[0045] By stabilizing the workpiece part 12 from the opposite side using the counter-support 52 and holding it in a horizontal orientation, the microjoints 14 can be cleanly cut through without the workpiece part 12 becoming stuck or jammed in the remaining workpiece 13. Ejection can be performed from either above or below. Due to the reduced height of the microjoints 14, the force required to cut them is not significantly higher than the force required to push the workpiece part 12 out of the cut gap, thus enabling reliable removal.

[0046] Preferably, the positioning of the ejection element 51 or ejection elements 51 is chosen such that the surface spanned by the ejection elements 51 is offset relative to the center of gravity of the workpiece part 12 in the direction of the microjoint(s) 14.

Claims

1. A method for removing a laser-cut, in particular plate-shaped workpiece part (12) from a workpiece remainder (13), wherein the workpiece part (12) is held from one of its sides by an in particular flat mating holder (52), in a tipping-safe manner, and is pushed out of the workpiece remainder (13) from the other side with at least one pushing-out element (51), wherein before it is removed, the workpiece part (12) is held in the workpiece remainder (13) by at least one microjoint (14) with a lower height (d) than the workpiece thickness (D), and wherein the microjoint (14) is severed upon removal.

2. The method according to claim 1, wherein the mating holder (52) is designed to take the workpiece part (12) away.

3. The method according to claim 2, wherein the mating holder (52) is designed as a lowerable conveyor belt.

4. The method according to claim 2, wherein the mating holder (52) is designed as a suction device (52), in particular a vacuum suction apparatus (52).

5. The method according to claim 4, wherein the mating holder (52) is arranged above the workpiece part (12) and is lowered from above onto the workpiece part (12) and a bordering edge region of the workpiece remainder (13), wherein the pushing-out elements (51) are arranged below the workpiece part (52) and are raised until they lie against the bottom side of the workpiece part (12), and thereby hold the workpiece part (12) in a tipping-safe manner between the pushing-out elements (51) and the mating holder (52), wherein the pushing-out elements (51) and the mating holder (52) are raised synchronously, whereby the workpiece part (12) is pushed upward out of the workpiece remainder (13), and in the process the microjoints (14) are severed, wherein the workpiece part (12) is then taken away by means of the mating holder (52).

6. The method according to any one of the preceding claims, in which the pushing-out element, or the center of mass of the area spanned by a plurality of pushing-out elements (51) is shifted away from the center of mass of the workpiece part (12) in the direction of the at least one microjoint (14).