阅读说明：本技术 在用高能射束切断固体时识别和加工已定义的轮廓的方法 (Method for identifying and processing defined contours during the severing of solids with high-energy beams ) 是由 亚历山德拉·舍尔曼 拉尔夫·施皮尔曼 于 2018-05-23 设计创作，主要内容包括：本发明涉及一种用于在借助高能射束切断固体时识别和加工已定义的轮廓的方法。为此在控制切断的控制单元中存储(S10)已定义的轮廓,并且当NC程序中出现已定义的轮廓时由控制单元识别(S12)已定义的轮廓。根据已编程的轮廓,控制单元使用于避免轮廓损伤的功能失效(S13)并且产生切割间隙(S14)。根据本发明,高能射束以平均的直线运动沿着轮廓行进。(The invention relates to a method for detecting and processing a defined contour when cutting through a solid body by means of a high-energy beam. For this purpose, the defined contour is stored (S10) in the control unit which controls the cutting-off, and the defined contour is recognized (S12) by the control unit when the defined contour occurs in the NC program. According to the programmed profile, the control unit disables the function for avoiding the damage of the profile (S13) and generates a cutting gap (S14). According to the invention, the high-energy beam travels along the profile with an even linear motion.)

1. A method for severing a solid body, wherein a high-energy beam travels along a contour on a surface of the solid body facing the high-energy beam and produces a cutting gap in the solid body, wherein a control unit controlling the severing has a function for identifying contour damage and a function for avoiding contour damage,

characterized in that at least one defined contour is stored (S10) in the control unit, the defined contour is identified (S12) by the control unit, and the avoiding of contour damage is automatically disabled (S13) when a contour is identified.

2. The method according to claim 1, wherein the high-energy beam is a laser beam and the severing of the solid body is effected by means of laser cutting.

3. Method according to claim 1 or 2, wherein the profile is specified in a numerical control program of a numerical control unit.

4. A method according to any one of claims 1 to 3, wherein the contours embodied as the defined contours are identified as bottlenecks by the function for identifying contour impairments.

5. Method according to any one of claims 1 to 4, wherein the defined profile is embodied as a groove, preferably as a curved groove.

6. The method according to any of claims 1 to 5, wherein the defined profile is implemented as an I-shaped groove (11), a rounded I-shaped groove (13), a T-shaped groove (12) or a rounded T-shaped groove (14).

7. A method according to any one of claims 4 to 6 wherein when a profile is identified as a bottleneck, the high energy beam travels along the profile in an even linear motion.

8. A control unit for carrying out the method according to any one of claims 1 to 7, wherein the control unit has a function for identifying contour lesions and a function for avoiding contour lesions,

characterized in that at least one defined contour can be stored in the control unit, the control unit being able to recognize the defined contour and, when a contour is recognized, to automatically disable the avoiding of contour damage.

9. The control unit of claim 8, for controlling a laser cutting machine.

Technical Field

The invention relates to a method for severing solid bodies, wherein a high-energy beam travels along a contour on the surface of the solid body facing the high-energy beam and a cutting gap is produced there, wherein a control unit controlling the severing has a function for identifying contour damage and for avoiding contour damage. The invention further relates to a control unit for carrying out such a method.

Background

At present, numerically controlled or computer-aided numerically controlled cutting machines are used for manufacturing or cutting metal sheets. A Numerical Control (NC) unit or a computer-aided numerical control (CNC) unit (hereinafter merely referred to as control unit) is a device for controlling a machine, which reads control instructions provided as codes on a data carrier and converts them into a workflow or a movement sequence. The groove to be produced is described as a contour in an NC program or CNC program (hereinafter merely program) in the control unit. The control unit also includes software that controls the trajectory of the cutter according to the NC program.

Such cutting machines are used in different technical fields. For example, metal sheets for the automotive industry and shipbuilding industry are cut in this way. In particular, cutting machines which form grooves in metal workpieces by means of high-energy beams, in particular laser beams or electron beams, are becoming increasingly popular.

For example, DE102004039916a1 describes a method for producing narrow grooves, for example holes, cuts or engravings in a metal workpiece, wherein a high-energy beam is injected into the workpiece and causes melting there.

The high-energy beam travels along the contour in order to produce the groove and thereby produces the cutting gap.

In modern control units, monitoring functions can be provided, which are used to prevent damage to the cutting machine and also to the workpiece. For example, a function for monitoring tool workpiece collisions (also referred to as recognizing contour damage) can be used, which is integrated in particular in the function for tool radius compensation. Here, the tool path of the cutting machine is monitored by predictive contour calculation. Thereby possible contour damage is identified in time and by removing the contour causing the contour damage, the control unit can prevent the contour damage by a function of avoiding the contour damage. Identifying a contour damage here identifies a contour at which more solid material is removed than originally intended while travelling along the contour and creating a cutting gap.

In addition, monitoring tool workpiece collisions can serve to identify bottlenecks. The bottleneck describes a contour that cannot be generated without damage to the contour. If one were to follow such a profile and create a cutting gap, more solid material would be removed than would otherwise be expected.

For example, if a contour or a partial contour whose entrance relative to the direction of travel of the high-energy beam is too small compared to the diameter of the high-energy beam is removed at the workpiece, the contour or partial contour is removed due to the function for avoiding damage to the contour. For this purpose, a size difference of only 1 μm or less is sufficient, since the accuracy of the control unit is in the range of μm and smaller. If the diameter of the high energy beam is only slightly larger than the programmed profile, the profile is removed.

It is possible to manually deactivate before the profile that leads to the profile damage and to reactivate after machining the profile damage prevention function, which profile describes the groove to be produced anyway, and in which the deviation between the programmed profile and the produced profile is not important. However, this leads to high costs.

Disclosure of Invention

The object of the invention is to provide a simplified method in which the high-energy beam also automatically follows the contour which leads to damage to the contour and produces the groove described by the contour.

This object is achieved by a method for severing a solid body, wherein a high-energy beam travels along a contour on a surface of the solid body facing the high-energy beam and produces a cutting gap in the solid body, wherein a control unit controlling the severing has a function for identifying contour damage and a function for avoiding contour damage, wherein at least one defined contour is stored in the control unit, the defined contour is identified by the control unit, and the avoidance of contour damage is automatically disabled.

The object is also achieved by a control unit for carrying out the method, wherein the control unit has a function for identifying contour damage and a function for avoiding contour damage, wherein at least one defined contour can be stored in the control unit, wherein the control unit can identify the defined contour and can automatically disable the avoiding of contour damage when a contour is identified.

The invention can be used particularly advantageously when cutting through solid bodies by laser cutting (also referred to as laser beam cutting). Further, laser cutting sometimes includes laser beam melting cutting, laser beam combustion cutting, and laser beam sublimation cutting. However, this method can also be used for separation of other manufacturing techniques, in which the shape of the workpiece is changed by eliminating local bonding. In this case, for example, water-jet cutting, gas cutting and plasma fusion cutting, or conventional separation methods such as milling, can be involved.

According to the invention, the control unit is used as a controller for the laser cutting machine.

Laser cutting is always well suited for the severing of solids when complex contours need to be machined quickly and almost energetically. Even in very narrow cutting gaps, laser radiation enables burr-free severing. Furthermore, only a small amount of heat is introduced into the solid. In addition to metallic materials such as structural steel, stainless steel and aluminum, laser cutting is also suitable for wood, plastic, glass and ceramics.

In an embodiment according to the invention, the control unit obtains two important information about the contour: at least one control command describing the grooves of the profile and information about at least one defined profile, which is preferably information about the profile causing damage to the profile, which describes the grooves to be produced anyway and not to be removed. The control commands are preferably present in the numerical control program and converted into a workflow by the control unit. According to the invention, the defined contour is stored in the control unit.

Preferably, the defined profile describes a groove in the form of a groove or a curved groove. The bending groove is a narrow groove, which in the exemplary embodiment is approximately 0.1mm to 1mm wide, and is preferably made in sheet metal. In particular, the bending groove is created at a position of the metal plate that needs to be folded or bent.

The profile of the curved slot typically exhibits an I-shape or T-shape. The so-called I-groove or T-groove can be rounded. However, the corners of the I-shaped or T-shaped groove have in principle a circular shape, which preferably results from a circular focus of the laser (also referred to as laser focus). However, the I-shaped and T-shaped grooves are also intentionally rounded to reduce the notching effect on the grooves or on the cut or notched profile or partial profile thereof.

In particular, a defined contour is stored in the control unit, which is recognized as a bottleneck and is therefore removed. This includes inter alia I-shaped and T-shaped slots.

According to the invention, the control unit identifies defined contours stored in the NC program and disables the avoidance of contour damage. Even if the contour is identified as a bottle neck, for example, and must be removed, a groove described by the defined contour is produced. However, since the defined contour is stored in the control unit, the control unit automatically recognizes the defined contour in the numerical control program and carries out the workflow. According to the invention, a function for recognizing the groove shape is integrated in the control unit.

According to the invention, only the groove is stored as a defined contour in the control unit. Here, the shape is important. The slot is preferably illustrated by three features: the grooves are perfectly straight, with two parallel tangents, and also have a defined length to width ratio. Typically, the ratio of the aspect ratio of the grooves is a factor of 200 to 400.

The defined contour stored in the control unit does not necessarily describe the complete contour (for example a groove) of the groove to be produced, but can also have only at least one piece of information about at least one feature of the defined contour.

The invention is particularly useful for simplifying the operation of the cutting machine in order to reduce the workload and associated costs for the end user. The method according to the invention is advantageous in particular in laser cutting, since severing of solids by means of a laser beam is regarded as less accurate.

The diameter of the laser focus of a laser cutting machine is closely related to the thickness of the material to be processed (e.g., metal sheet). In general, what applies in this case is: the thicker the metal plate, the more energy is required for the laser to create the grooves. If more energy is needed because, for example, the metal plate is thicker, the diameter of the laser focal spot increases. Therefore, if, for example, instead of using a metal plate having a thickness of 0.1cm, a metal plate having a thickness of 10cm, for example, should be processed, it is desirable to significantly increase the diameter of the laser focal point.

In an exemplary embodiment, since the thickness of the metal plate is increased from 0.5cm to 1cm, the diameter of the laser focal point is larger than the contour width of the existing I-shaped groove in the NC program, and thus the control unit recognizes the bottleneck. Since the contour damage is avoided, the I-shaped groove is not generated. However, according to the invention the profile of the I-shaped groove is stored as a defined profile in the control unit. If the control unit identifies a stored defined contour, the automatic disabling of the avoiding of the damage to the contour is effected and the contour is machined. Preferably, the control unit averages the linear movement of the laser within the programmed contour of the I-groove in order to minimize errors and deviations. Here, slight profile damage of the I-shaped groove can be tolerated. A cutting machine working according to the prior art standard cannot implement an I-shaped groove programmed for a sheet metal thickness of 0.5cm on a sheet metal of 1cm thickness, since identifying contour damage identifies a bottleneck.

The machining accuracy of the laser cutting machine is usually 0.1 mm. However, the accuracy of the control unit is in the range of μm and smaller. Due to the aging of the focusing lens of the laser in the laser cutting machine, it is even necessary to additionally increase the laser focus in order to be able to apply the desired energy. Thus, with respect to the illustrated grooves and curved grooves, machining of the solid to the μm precision is neither possible nor necessary.

The function for identifying the contour damage and the function for avoiding the contour damage can be provided as separate functions or can also be used in combination.

Drawings

The invention will be further elucidated and described with reference to an embodiment shown in the drawings.

Figure 1 shows an exemplary flow of a method for cutting solids,

figure 2 shows the profile of an I-shaped groove,

figure 3 shows the profile of a T-shaped slot,

figure 4 shows the profile of a rounded I-shaped groove,

figure 5 shows the profile of a rounded T-shaped groove,

fig. 6 shows the average linear motion for achieving a rounded I-shaped groove.

Detailed Description

In a method step S10, the stored defined contour is a curved groove, in particular in the form of an I-groove, a T-groove, a rounded I-groove or a rounded T-groove, the stored defined contour in any case should follow this contour and produce a cutting gap, even if, for example, the cutting gap produced after machining the solid is greater than the cutting gap stored in the NC program and initially set to be implemented, in a method step S11, the control unit searches for a contour in the NC program, which is identified by the identification contour damage as a contour which leads to the contour damage, for example as a bottleneck, if no bottleneck is identified (in the diagram labeled with F? and n), in a method step S3963, the contour is identified as a contour which leads to the contour damage by the identification contour in the NC program as a straight line in a method step S35n, if the cutting profile is marked with a high-energy beam, the laser beam in the laser cutting machine is used as a high-energy beam, the laser beam is particularly suitable as a high-energy beam, the control unit is preferably integrated into the laser cutting machine, however, a plurality of defined contours can also be stored.

Fig. 2 shows the outline of the I-shaped groove 11. The laser focus 2 of the laser beam runs along the contour 11 on the metal sheet 1. In an exemplary embodiment, the laser focus first travels along the upper portion of the profile and then immediately follows the lower portion of the profile. However, if the diameter of the laser focus 2 is as wide as the contour or wider than the contour for the reasons already explained, the function for avoiding contour damage prevents the generation of cutting gaps in laser cutting machines according to the prior art. According to the invention, the I-shaped groove 11 is stored in a control unit, which recognizes the groove as a defined contour according to the function for recognizing the groove shape and generates a cutting gap. According to the invention, the control unit averages the linear motion in order to be able to keep the errors and deviations of the contours programmed in the NC program as small as possible. This averaged linear motion will be explained in more detail in fig. 6.

In fig. 3, a method sequence as already shown in fig. 2 is used. Fig. 3 shows the profile of the T-shaped groove 12. The laser focus 2 of the laser beam runs along the contour 12 on the metal sheet 1. In an exemplary embodiment, the laser focus first travels along the upper portion of the profile and immediately follows the lower portion.

Fig. 4 shows the T-shaped groove 12 already described in fig. 3 as a rounded T-shaped groove 14. Fig. 5 shows the I-shaped groove 11 already described in fig. 2 as a rounded I-shaped groove 13. However, the corners of the I-or T-shaped groove have in principle a circular shape, which preferably originates from the circular laser focus 2. However, the I-and T-shaped grooves are also intentionally rounded in order to reduce the notching effect on the grooves or on the contours or portions thereof that are cut or notched.

The grooves shown in fig. 2 to 5 (I-groove, rounded I-groove, T-groove and rounded T-groove) can be used in the NC program preferably as straight and/or circular sections in the NC or CNC partial programming language.

Fig. 6 shows the averaged linear movement 21 of the laser focus 2 of the laser cutting machine as a result of the method according to the invention. Fig. 6 shows the contour of the rounded I-shaped groove 13 in the metal plate 1. In this embodiment, the rounded I-shaped groove 13 serves as a curved groove. Small profile errors and deviations do not have a large effect on the curved groove. However, the end user is very much focused on making curved slots in any case. However, the diameter of the laser focus 2 is wider than the rounded I-shaped groove 13. The control unit working according to the prior art does not follow the contour and does not create a cutting gap due to the function for avoiding damage to the contour. The method according to the invention achieves that the cutting gap is produced according to the function for identifying the groove shape, since the contour of the I-shaped groove is identified by the control unit, in which it is just stored beforehand. In order to keep the profile error as small as possible, the control unit averages the linear movement of the laser focus 2 according to the invention. In fig. 6, the laser focus 2 travels from right to left centrally along line 21 inside the profile. In an exemplary embodiment, the programmed profile is measured as an I-slot 0.3mm wide, ultimately enabling a 0.4mm wide cutting gap to be implemented. However, such slight profile damage can be tolerated, in particular in the case of curved grooves.