DE102021202636A1 - Method for moving a machining head of a blasting tool during a break in machining - Google Patents

Abstract

The invention relates to a method for moving a machining head (12), which can be moved along a plurality of machine axes (22, 24, 26) with maximum dynamics, of a blasting tool (10) during a machining pause, the method having the following steps: A) specifying a transfer path (52 , 54) for the machining head (12) starting from a machining end position (42, 44) on a workpiece (14, 16),B) specifying a retraction distance (54),C) calculating a movement path (56, 58) taking into account the maximum dynamics , the movement path (56, 58) being increasingly shifted in the direction of the retraction path (54) relative to the transfer path (50, 52), D) moving the machining head (12) starting from the machining end position (42, 44) along the movement path (56 , 58). The invention also relates to a computer program for carrying out step C) and a blasting tool with a control device for carrying out step C).

Description

Background of the Invention

The invention relates to a method for moving a machining head of a blasting tool that can be moved along a plurality of machine axes with maximum dynamics during a machining pause, with a transfer path for the machining head being specified starting from a machining end position on a workpiece.

Such a procedure is, for example, from WO 2012/104053 A1 known.

The processing of workpieces with beam tools, such as laser cutting systems, often takes place in several processing phases, which are interrupted by processing breaks. During the machining phases, a machining beam is directed onto the workpiece by a machining head of the beam tool, so that the workpiece is machined. No processing beam is emitted by the processing head during the processing pauses. During the breaks in processing, the processing head can be positioned for further processing of the workpiece in a respective subsequent processing phase.

In order to compensate for deviations in position and shape of the workpiece during the actual machining (i.e. in the machining phases), it is known to measure a distance between the workpiece and the machining head before machining and to correct it if necessary (see EP 3 062 959 B1 ) or to regulate the distance between the workpiece and the processing head to a target value during processing (see the above-mentioned WO 2012/104053 A1 or EP 3 265 267 B1 ). According to EP 3 265 267 B1 a dynamic axis, for example an additional quill, can be provided specifically for distance control.

In the processing pauses, the processing head is typically moved from a processing end position of the previous processing phase to a processing start position of the subsequent processing phase. Due to deviations in the positioning of the workpiece on the blasting tool and dimensional deviations in the workpiece itself (for example in the case of deep-drawn sheet metal), there is a risk that the processing head will collide with the workpiece.

To avoid this, according to JP2008200712A , when the workpiece extends in an XY plane, the machining head can be pulled away from the workpiece in a Z direction perpendicular thereto. However, such an approach can significantly increase the overall processing time.

According to the above WO 2012/104053 A1 a laser cutting head can be moved along a defined path of movement to a starting position for a further single cut after the end of a single cut. The movement path can be defined by means of measured distance values that were obtained by a distance measuring device during the previously executed individual separating cut. However, this assumes that the movement to the next starting position is essentially along a section of the previously executed single severing cut and that the starting position lies on the cutting line of the previous single severing cut.

object of the invention

It is an object of the invention to avoid collisions of a machining head of a blasting tool with a workpiece subject to tolerances in a simple and efficient manner during movements of the machining head during breaks in machining.

Description of the invention

This object is achieved according to the invention by a method according to claim 1, a computer program according to claim 14 and a blasting tool according to claim 15.

According to the invention, a method for moving a machining head of a blasting tool during a break in machining is provided. The beam tool can be a laser tool, for example a laser welding system or, in particular, a laser cutting system. Alternatively, the beam tool can be an electron beam tool, a plasma beam tool or a water jet tool, for example. The beam tool is set up to direct a processing beam, for example a laser beam, onto the tool in order to process it, for example to cut it. For this purpose, the processing beam can exit from the processing head. The method can be carried out using a computer program according to the invention described below. The method can be carried out using a blasting tool according to the invention described below.

The machining head can be moved along a plurality of machine axes relative to the workpiece or, if appropriate, to a plurality of workpieces clamped at the same time. The movement of the machining head relative to the workpiece can be achieved by moving the machining head and/or that of the workpiece, for example by means of a movable tool table. The machine axes can each be a linear axis or a rotary axis. When moving along a linear axis, the machining head can be moved in a translatory manner in the direction of the respective machine axis. When moving along a rotary axis, the machining head can be rotated about the respective machine axis. The blasting tool typically does not have any redundant machine axes.

Maximum dynamics are available for moving the processing head along the machine axes. In other words, the movement of the processing head can take place with maximum dynamics at most. The maximum dynamics describes in particular the maximum speeds and/or accelerations along the respective machine axes. In other words, the machining head can be moved along each machine axis with a maximum (translational or rotational) speed or a maximum (translational or rotational) acceleration. The maximum speeds and/or accelerations can be different for different machine axes. The maximum possible speeds and/or accelerations can be the same for some of the machine axes.

The procedure is carried out during a break in processing. During the processing pause, the processing head basically does not emit any processing beam, in particular no laser beam, for processing the workpiece. Before and after the machining head is moved during the machining pause, the workpiece (or two workpieces) is typically machined in a respective machining phase by a machining beam emitted by the machining head, for example a laser beam. It goes without saying that the processing head is typically also moved during the processing phases.

1. A) Vorgeben eines Transferpfades für den Bearbeitungskopf ausgehend von einer Bearbeitungsendposition an einem Werkstück,
2. B) Vorgeben einer Rückzugsstrecke,
3. C) Berechnen eines Bewegungspfades unter Berücksichtigung der Maximaldynamik, wobei der Bewegungspfad gegenüber dem Transferpfad zunehmend entlang der Rückzugsstrecke verschoben ist,
4. D) Bewegen des Bearbeitungskopfs ausgehend von der Bearbeitungsendposition entlang des Bewegungspfades.

The procedure has the following steps:

1. A) specification of a transfer path for the processing head starting from a processing end position on a workpiece,
2. B) specification of a retreat distance,
3. C) Calculation of a movement path taking into account the maximum dynamics, the movement path being increasingly shifted along the retreat path compared to the transfer path,
4. D) Moving the machining head along the movement path, starting from the machining end position.

With a workpiece designed and positioned without deviations, the machining head could be moved along the transfer path from the machining end position of a previous machining phase to a starting position for machining the workpiece in a subsequent machining phase. For this purpose, the transfer path contains location information and typically at least implicit speed information. The transfer path typically describes a translatory movement of the machining head. Additionally or alternatively in special cases, the transfer path can describe a rotational movement of the processing head. The transfer path can specify the positions and, if applicable, the speeds of the machining head in a machine coordinate system or in relation to the respective machine axes. The location information can be specified in absolute terms (in particular in the machine coordinate system). Typically, the transfer path is specified relative to the workpiece. As a result, a previously determined positional deviation of the workpiece can be compensated for. In particular, the transfer path can be specified as a path with supporting points. The specification in step A) can take place by storing the transfer path in a CAD and/or CAM system. In particular, the transfer path can be specified by storing it in an NC program for controlling the blasting tool.

In step B), a retreat path is specified. In particular, a length and/or a direction of the retreat path can be specified. Provision can be made for the retraction path to run counter to a beam propagation direction of a machining beam that can be emitted by the machining head, unless a different direction is specified. The retraction section serves to set up a safety distance between the workpiece and the processing head, in particular a nozzle for the exit of the processing jet and possibly a process gas, during the movement of the processing head starting from the processing end position. If the exact position of the workpiece is not known, either because the workpiece is positioned imprecisely or because the workpiece has dimensional deviations, this additional safety distance can prevent collisions between the processing head and the workpiece.

Steps A) and B) can be carried out in any order or simultaneously.

In step C) (after carrying out steps A) and B)), a movement path for the processing head is calculated. The movement path is calculated in such a way that it is progressively shifted along the retreat path compared to the transfer path. In other words, the movement path starts at the machining end position. The movement path now runs essentially along the transfer path, however, at least initially, moves further and further away from the transfer path as the distance (measured along the transfer path) from the processing end position increases. If the movement path has moved away from the transfer path by the retreat distance, it runs consistently offset by the retreat distance relative to the transfer path.

When calculating the movement path, the retraction distance is preferably only taken into account to the extent that the end of the transfer path is not reached when the machining head moves along the movement path. In other words, the movement path does not reach the distance from the transfer path predetermined by the retreat path if the movement has already ended beforehand.

The movement path contains location information and at least implicitly speed information. The movement path can specify the positions and, if applicable, the speeds of the machining head in a machine coordinate system or in relation to the respective machine axes. The location information can be calculated absolutely (in particular in the machine coordinate system). Alternatively, the movement path can be calculated relative to the workpiece or relative to the machining end position.

The movement path is calculated taking into account the maximum dynamics of the processing head or the blasting tool. In other words, it is ensured during the calculation that the processing head adheres to the dynamic limitations of the beam tool during the subsequent movement along the movement path. Compliance with the dynamic limitations, i. H. the maximum dynamics, is already taken into account when calculating the movement path. The calculation is carried out in such a way that the speeds and accelerations occurring along the movement path do not exceed the maximum values possible in each case - and not in such a way that compliance with the maximum dynamics only results from the inability of the blasting tool to exceed its dynamic limits during the movement.

Then, in step D), the processing head is moved along the movement path. The calculation of the movement path in step C) can take place completely before the movement of the machining head in step D). Alternatively, the calculation of the movement path can be carried out at least in part at runtime, i. H. during the movement of the machining head in step D). By taking into account the retraction path, the movement of the machining head runs at a greater distance from the workpiece than would be the case if the machining head were to move along the transfer path. This effectively reduces the risk of collisions. In particular, the machining head is at a greater distance from the workpiece at the end of the movement path than would be the case with a movement exclusively along the transfer path. At least at the beginning of the subsequent machining phase, this increased distance protects the machining head, in particular its nozzle, from colliding with the workpiece. However, if necessary, the processing head can be brought back to the workpiece by the retraction distance before the start of the next processing phase.

As a result of the movement along the movement path, there is (at least at the beginning) a movement in the direction of the withdrawal path and along the transfer path at the same time. Since this retraction movement takes place during the transfer movement - and not beforehand - the movement of the processing head during the processing pause takes little time. For example, the blasting tool can work 5% faster with greater (process and system) safety. The productivity of the blasting tool, which is increased by the method according to the invention, lowers the production costs for the workpiece. Furthermore, it is possible to avoid taking the transfer path unnecessarily far away from the workpiece, which in turn would increase the time required for the movement. In addition, a transfer path that is excessively far away from the workpiece can lead to geometry errors on the workpiece, especially if the movement along the transfer path requires orientation changes (rotations) of the machining head. This can be avoided by the procedure according to the invention. Finally, according to the invention, a redundant machine axis for increasing the distance can be dispensed with, which would be associated with corresponding costs for hardware and software. The method according to the invention enables the use of a low-complexity blasting tool.

The retreat distance can be specified by an operator. The method can be made particularly simple in this way. the When specifying the retraction distance, the operator can take into account the special features of the workpiece or a group of workpieces to be machined.

Alternatively, the retreat distance can be determined automatically by a control device of the blasting tool. This enables the method to be carried out particularly quickly and in a highly automated manner. The retraction distance can be determined automatically using workpiece data and/or properties of the blasting tool. These can be stored in the control device or in a CAD/CAM system that the control device can access. The workpiece data can in particular include information that allows conclusions to be drawn about its possible dimensional deviations, for example information about the size of the workpiece or about previous processing. A property of the jet tool can be, for example, the length of a nozzle for exiting a machining jet at the machining head.

The retraction distance can be specified relative to a target value of the machining end position. As a result, deviations in the positioning of the machining head that occurred during the machining of the workpiece in the preceding machining phase (for example due to a distance control) are not taken into account for the subsequent movement of the machining head. This is useful if it can be assumed that the deviations that occurred previously on the workpiece will not continue in the direction of the transfer path.

Alternatively, the retraction distance can be specified relative to an actual value of the machining end position. In other words, the retreat distance can be specified relative to the actual position of the machining head at the end of the previous machining phase. Deviations in the positioning of the machining head that occurred during the machining of the workpiece in the previous machining phase (for example due to distance regulation) are thereby taken into account for the subsequent movement of the machining head. This is useful if it can be assumed that the deviations that previously occurred on the workpiece will continue in the direction of the transfer path.

When calculating the movement path, a speed for the processing head along the transfer path can be slowed down to such an extent that the maximum dynamics are maintained. In other words, movement along the transfer path can be slowed down until movement toward the retreat path is complete. This makes it possible to remove the machining head from the workpiece particularly quickly by the retraction distance.

When specifying the transfer path, a dynamic reserve for maximum dynamics of the blasting tool can be provided or set up. The dynamic reserve is preferably available over the entire transfer path. The dynamic reserve can be used for the partial movement along the retreat route. The dynamic reserve can be specified by an operator. The specified transfer path only uses a transfer dynamic that is smaller (by the dynamic reserve) than the maximum dynamic. The dynamic reserve can be specified by a proportion of the maximum dynamic. For example, it can be provided that the movement along the transfer path may utilize a maximum of 80% of the maximum dynamics. At least the remaining 20% of the maximum dynamics are then always available as a dynamic reserve for the movement in the direction of the retreat path. Insofar as the movement along the transfer path does not exhaust the maximum part of the maximum dynamics assigned to it at times, the movement in the direction of the retreat path can take place with a correspondingly increased dynamic.

Alternatively, the dynamic reserve can be used when calculating the movement path to set a speed for the processing head along the retraction path. Provision can thus be made for the movement in the direction of the retreat distance to make full use of the dynamic reserve until the movement path by the retreat distance is removed from the transfer path.

When calculating the movement path, the movement in the direction of the withdrawal path can be limited overall to the portion of the maximum dynamics that remains due to the movement along the transfer path. In other words, a portion of the speed attributable to the retraction movement can always run parallel to the retraction path.

Alternatively, when calculating the movement path, the movement in the direction of the retraction path in the machine axes involved can be limited to the portion of the maximum dynamics that remains due to the movement along the transfer path. In other words, each machine axis involved in the retraction movement can fully utilize the part of the maximum dynamics not utilized by the transfer movement. The machining head thus generally does not move away from the transfer path parallel to the retraction path however, finally the offset defined by the retreat distance compared to the transfer path.

In an advantageous variant of the method, it is provided that a plurality of transfer paths for the processing head are specified, each starting from an associated processing end position. The multiple machining end positions or transfer paths can relate to the same workpiece or multiple workpieces clamped together. The processing head could be moved along the multiple transfer paths from the respectively associated processing end position of a previous processing phase to a starting position for processing the workpiece or one of the workpieces in a respective subsequent processing phase, provided there are no deviations in the positioning and shape of the workpiece or workpieces .

In this variant of the method, only a single return path is specified for the multiple transfer paths. Using the same retreat route, a movement path can be calculated in each case, taking into account the maximum dynamics, with the respective movement path being increasingly shifted along the retreat route compared to the associated transfer path. The same retraction path can thus be used to avoid collisions when moving the processing head in several processing pauses. This is particularly useful if similar deviations in the dimensions or positioning of the workpiece or workpieces are to be expected. The multiple use of the same retreat path further simplifies the implementation of the method.

Finally, the machining head is moved along the respective movement paths starting from the machining end positions. From the positions of the machining head reached in this way, further machining of the workpiece or workpieces can take place.

This variant of the method thus provides for steps A), C) and D) to be carried out multiple times. In contrast, method step B) is carried out only once.

The scope of the present invention also includes a computer program comprising program instructions which, when the computer program is executed on a control device for a blasting tool with a machining head that can be moved along a number of machine axes with maximum dynamics, cause the control device to carry out step C) of a method according to the invention described above . The control device can have a computer or be designed as a computer. The computer program can include program instructions which, when the computer program is executed on the control device, cause the latter to receive a transfer path starting from a processing end position. Furthermore, the computer program can include program instructions which, when the computer program is executed on the control device, cause the latter to obtain a retreat path. Alternatively, it can be provided that the computer program includes program instructions which, when the computer program is executed on the control device, cause the control device to automatically determine the retraction distance, in particular using workpiece data and/or properties of the blasting tool.

A computer program product on which such a computer program is stored also falls within the scope of the present invention. A computer program product is understood to mean a computer-readable storage medium that contains the computer program in computer-readable form.

Finally, a blasting tool with a machining head that can be moved along a number of machine axes with maximum dynamics and a control device falls within the scope of the invention. The beam tool can be a laser tool, for example a laser welding system or, in particular, a laser cutting system. Alternatively, the beam tool can be an electron beam tool, a plasma beam tool or a water jet tool, for example. The beam tool is set up to direct a processing beam, for example a laser beam, onto the tool in order to process it, for example to cut it. For this purpose, the processing beam can exit from the processing head. The control device can have a computer or be designed as a computer.

The control device is set up to carry out step C) of a method according to the invention described above. For this purpose, the control device can execute a computer program according to the invention as described above. The computer program can be stored in the control device. The control device can be set up to receive a transfer path starting from a processing end position. Furthermore, the control device can be set up to obtain a retreat path. Alternatively, the control device can be set up to automatically determine the retreat distance, in particular using workpiece data and/or properties of the blasting tool. Finally, the control device can be set up to carry out step D) of the above-described to carry out the method according to the invention, ie to move the machining head by means of the machine axes of the beam tool, starting from the machining end position along the movement path.

Further advantages of the invention result from the description and the drawing. According to the invention, the features mentioned above and those detailed below can each be used individually or collectively in any desired, expedient combination. The embodiments shown and described are not to be understood as an exhaustive list, but rather have an exemplary character for the description of the invention.

character list

• 1 ein erfindungsgemäßes Strahlwerkzeug mit einem Bearbeitungskopf zum Bearbeiten von Werkstücken in einer schematischen Seitenansicht;
• 2 eine schematische Draufsicht auf einen Werkstücktisch des Strahlwerkzeugs von 1, auf welchem die Werkstücke aufgespannt sind;
• 3 ein schematisches Ablaufdiagramm eines erfindungsgemäßen Verfahrens zum Bewegen eines Bearbeitungskopfs eines Strahlwerkzeugs in einer Bearbeitungspause;
• 4 ein schematisches Diagramm eines Bewegungspfades, der gegenüber einem von einem Istwert einer Bearbeitungsendposition ausgehenden Transferpfad zunehmend um eine Rückzugsstrecke versetzt ist;
• 5 ein schematisches Diagramm eines Bewegungspfades, der gegenüber einem von einem Sollwert einer Bearbeitungsendposition ausgehenden Transferpfad zunehmend um eine Rückzugsstrecke versetzt ist;
• 6 ein schematisches Geschwindigkeitsdiagramm für einen Bearbeitungskopf, wobei für die Bewegung in Richtung einer Rückzugsstrecke eine konstante Reservedynamik ausgenutzt wird;
• 7 ein schematisches Geschwindigkeitsdiagramm für einen Bearbeitungskopf, wobei ein Geschwindigkeitsanteil für eine Rückzugsbewegung dem von einer Bewegung entlang eines Transferpfades nicht genutzten Anteil an einer Maximaldynamik entspricht, sodass eine Bewegung entlang eines Bewegungspfades zunächst die gesamte Maximaldynamik ausnutzt.

The invention is illustrated in the drawing and is described using exemplary embodiments. Show it:

• 1 a beam tool according to the invention with a machining head for machining workpieces in a schematic side view;
• 2 a schematic plan view of a workpiece table of the blasting tool of FIG 1 , on which the workpieces are clamped;
• 3 a schematic flowchart of a method according to the invention for moving a processing head of a beam tool in a processing pause;
• 4 a schematic diagram of a movement path, which is increasingly offset by a retraction distance compared to a transfer path starting from an actual value of a machining end position;
• 5 a schematic diagram of a movement path, which is increasingly offset by a retraction distance compared to a transfer path starting from a desired value of a machining end position;
• 6 a schematic speed diagram for a machining head, wherein a constant reserve dynamics is used for the movement in the direction of a retraction path;
• 7 a schematic speed diagram for a processing head, wherein a speed component for a retraction movement corresponds to the component of maximum dynamics not used by a movement along a transfer path, so that a movement along a movement path initially utilizes the entire maximum dynamics.

1 shows a blasting tool 10 in a schematic side view. The beam tool 10 is a laser cutting system here, for example. The blasting tool 10 has a processing head 12 . The processing head 12 makes it possible to direct a processing beam onto the workpieces 14, 16 to be processed. The processing head 12 can have a nozzle 18 from which the processing jet emerges, possibly together with a process gas. A beam source, for example a laser light source, can be arranged in the processing head 12 or at a distance from it and can be connected to the processing head 12 via a beam line device (not shown in more detail).

The workpieces 14, 16 can be held on a workpiece table 20 of the steel tool 10. 2 shows a top view of the workpiece table 20 with the workpieces 14, 16.

In order to move the machining head 12, several machine axes 22, 24, 26 are provided. The machine axes 22, 24, 26 are in the present case designed as axes for the translational movement of the machining head 12 in the X, Y or Z direction of a machine coordinate system of the blasting tool 10. In addition, it can be provided that the machining head 12 can be rotated about one or more machine axes (not shown in detail). Maximum dynamics are available for the movement of the machining head 12 along the machine axes 22, 24, 26. In other words, the possible speeds and/or accelerations of the machining head 12 relative to the workpiece table 20 are limited, for example due to structural properties of the machine axes 22, 24, 26 and/or due to technical control properties of a control device 28.

The workpieces 14, 16 can be three-dimensionally shaped sheet metal parts, for example. The workpieces 14, 16 can have shape and dimensional deviations, in particular as a result of previous processing, through which the three-dimensional shape of the workpieces 14, 16 was achieved, for example a deep-drawing process. Furthermore, the clamping of the workpieces 14, 16 on the workpiece table 20 can be accompanied by positional deviations.

In the present case, it is provided, for example, that a plurality of cutting lines 30, 32, 34 are to be made in the workpieces 14, 16, cf 2 . In order to produce the cutting lines 30, 32, 34, the processing head 12 is moved in several processing phases above the cutting lines 30, 32, 34 over the workpieces 14, 16, while a processing jet and, if necessary, a supporting process gas emerge from the nozzle 18. A distance between the nozzle 18 and the respective workpiece 14, 16 can be regulated to a desired value. In 1 the corresponding processing paths 36, 38, 40 of the tip of the nozzle 18 are drawn in with solid lines.

After generating one of the cutting lines 30, 32, the processing head 12 is to be brought from a respective processing end position 42, 44 to a starting position 46, 48 for the respective subsequent processing phase. A transfer path 50, 52 is specified for this in each case, compare step 102 in the flowchart in FIG 3 . The transfer paths 50, 52 can be stored in the control device 28. If the workpieces 14, 16 are manufactured with dimensional accuracy and are positioned exactly as intended on the workpiece table 20, the transfer paths 50, 52 allow the machining head 12 to move from the machining end positions 42, 44 to the starting positions 46, 48 without collision for the respective subsequent machining proceedings. Due to unavoidable dimensional and positional deviations of the workpieces 14, 16, however, there is a risk that the machining head 12, in particular its nozzle 18, could collide with the workpieces 14, 16 when moving along the transfer paths 50, 52.

In order to avoid this, in a step 104 a retreat path 54, cf 4 , default. The retraction distance 54 can be defined by a specific length, for example 5 mm, and a specific direction, for example the Z-direction. The retraction path 54 can be specified by an operator on the basis of deviations that experience has shown that workpieces of this type occur. Alternatively, the retreat distance 54 can be determined automatically by the control device 28, for example based on the largest dimensions of the workpieces 14, 16 and taking into account their previous forming, for example during deep drawing. The retraction path 54 is preferably specified in the same way for all machining phases to be carried out in one setting, ie only a single retraction path 54 is specified for a number of different transfer paths 50, 52. The same retraction path 54 can also be specified for a plurality of workpieces to be clamped one after the other, in particular when workpieces of the same type are machined one after the other.

Using the retraction path 54, a respective movement path 56, 58 for the machining head 12 is then calculated in a (respective) step 106 from the transfer paths 50, 52, see also 1 . In 2 the projections in the XY plane of the transfer paths 50, 52 and the movement paths 56, 58, which here fall on one another by way of example, are drawn in with dashed lines. The movement paths 56, 58 can be calculated using a corresponding computer program in the control device 28 of the blasting tool 10.

When calculating the movement paths 56, 58, the maximum dynamics of the beam tool 10 is taken into account. The movement paths 56, 58 are therefore calculated in such a way that when the machining head 12 is moved along the respective movement path 56, 58 to be carried out in a step 108, the dynamic limitations of the blasting tool 10 are maintained. The movement paths 56, 58 increasingly move away from the associated transfer paths 50, 52 until they are offset relative to them (in terms of amount and direction) by the retreat distance 54. If this offset has softened before the end of the respective movement path 56, 58 or the associated transfer path 50, 52 (time t1 in 4 ), it is retained until the end of the respective movement path 56, 58. In other words, movement path 56 runs from point in time t1 with a constant parallel offset relative to transfer path 50.

If, in exceptional cases, due to the dynamic limitations, the displacement of the movement path by the retreat distance relative to the transfer path cannot be achieved before the end of the movement path or transfer path, the movement in the direction of the retreat distance is aborted; i.e. H. the starting position for the subsequent processing is offset from the transfer path by less than the length of the retraction path (not shown in more detail).

As in 4 is shown, the retraction path 54 can be predetermined based on an actual value of the machining end position 42 . In this case, the transfer path 50 is also typically defined on the basis of the actual value of the machining end position 42 . Due to a distance regulation for the machining head 12, the actual value of the machining end position 42 can deviate from a target value which would be reached if the workpieces 14, 16 had no positional or dimensional deviations whatsoever.

Alternatively, the retraction path 54 and the transfer path 50 can also be specified on the basis of the aforementioned target value of the machining end position 42', see FIG 5 . The movement path 56 then does not begin on the transfer path 50, but already offset in relation to it (by the deviation between the actual value and the desired value caused by the distance control).

In a step 108, the processing head 12 is moved along the movement path 56, 58 starting from the processing end position 42, 44 to the associated starting position 46, 48 for the respective subsequent processing phase, compare 1 . By taking into account the retraction path 54, the starting positions 46, 48 are further away from the workpieces 14, 16 than an end point of the transfer paths 50, 52.

Starting from the starting positions 46, 48, the further processing of the workpieces 14, 16 takes place in a respective step 110. For this purpose, a processing beam, in this case a laser beam, is directed by the processing head 12 onto the workpieces 14, 16, so that the cutting lines 32, 34 are generated . The distance between the nozzle 18 and the workpieces 14, 16 can in turn be regulated to a desired value.

Various strategies can be used to ensure compliance with maximum dynamics. These are each described individually below; however, combinations are also conceivable.

For example, it can be provided that the speed and/or acceleration for the processing head 12 along the transfer path 50, 52 is reduced to such an extent that the maximum dynamics are maintained. In the extreme case, the entire maximum dynamics can be used for the movement in the direction of the retreat path 54 . Alternatively, a predefined part of the maximum dynamics, for example 50%, can be used for the movement in the direction of the retreat path 54 . The movement along the transfer path 50, 52 is then limited to the remaining part of the maximum dynamic range. As soon as the offset between the movement path 56, 58 and the associated transfer path 50, 52 has reached the length of the retraction path 54 (possibly in the respective machine axis 22, 24, 26), the movement in the direction of the transfer path 50, 52 is resumed with the dem Transfer path 50, 52 corresponding dynamics added. In both cases, the movement along the movement path 56, 58 can initially take place with full utilization of the maximum dynamics of one or more of the machine axes 22, 24, 26.

When specifying the transfer path 50, 52, a dynamic reserve for maximum dynamics of the blasting tool 10 can be set up. The dynamic reserve is preferably available to a minimum extent over the entire transfer path 50, 52. 6 shows by way of example that the machining head 12 can be moved along one of the machine axes 22, 24, 26, for example the Z axis 26, at a maximum speed v_max.

A specific part of this maximum speed v_max, namely the reserve speed v_res, should be available at all times for the movement in the direction of the retreat path 54 . The permissible speed v_zul for the movement along the transfer path 56, 58 in the relevant machine axis 22, 24, 26 is therefore limited to v_zul=v_max−v_res. In 6 the speed curve for the transfer path 56 is drawn in with a solid line in the Z-axis 26 shown as an example. The limitation of the speed for the transfer path leads to the plateau at the level of v_zul.

The movement in the direction of the retraction section 54 can (insofar as the acceleration capacity of the blasting tool 10 permits this, in particular initially) take place at the constant reserve speed v_res until the movement path 56, 58 is offset in the relevant direction by the length of the retraction section 54 in relation to the transfer path 50, 52 is. this is in 6 marked with a dotted line.

The superimposition of the two speed components, ie the speed of the machining head 12 along the movement path 56, 58 is in 6 marked with a dashed line. This increases up to the maximum speed v_max, since the permissible speed v_zul is to be utilized for the transfer path before the movement path 56, 58 has moved away from the transfer path 50, 52 by the retreat distance 54. The speed of the processing head 12 along the movement path 56, 58 drops to the course of the speed along the transfer path 50, 52 as soon as the movement in the direction of the retraction path 54 is completed at time t1.

The speeds in the other machine axes 22, 24 can also be defined as previously described, provided the retraction path 54 has a corresponding directional component. This applies accordingly to the allocation of the maximum possible acceleration to the movements along the transfer path 50, 52 and in the direction of the retreat path 54.

7 FIG. 12 shows an exemplary course of the speed for the machining head along the transfer path 50, 52 with a solid line. The speed shown can be the speed in the Z-direction (along the machine axis 26). It is provided here that the movement of the processing head 12 in the direction of the retraction path 54 is not terminated by the movement along the transfer path 50 , 52 used part of the maximum dynamic is limited. The speed of the machining head 12 along the path of travel 56, 58 (in 7 drawn in with a dashed line) therefore corresponds to a maximum speed v_max defined by the maximum dynamics until the movement path 56, 58 has moved away from the transfer path 50, 52 in the direction under consideration by the corresponding length portion of the retreat path 54. This is the case here at time t1. Before time t1, a retraction speed v_r in the direction of retraction path 54 results from the difference between maximum speed v_max and the speed along transfer path 50, 52. At time t1, the speed of processing head 12 drops to the speed along transfer path 50, 52. The maximum possible acceleration of the processing head 12 can be distributed in a corresponding manner between the transfer movement and the retraction movement.

As described above by way of example, the retraction path 54 can point in the direction of one of the machine axes, e.g. the Z-axis 26. In general, however, the retraction path 54 can also have components in one or more of the other machine axes 22, 24. Possibilities for distributing the dynamics are described below if the retraction path 54 has portions in several of the machine axes 22, 24, 26.

The respective possible maximum speeds for the individual axes can be distributed independently of one another in the manner described above. Consequently, the maximum dynamics of each machine axis 22, 24, 26 involved can be used to pull the machining head 12 back from the transfer path 50, 52. Consequently, with this procedure, the retraction movement generally does not take place parallel to the retraction path 54.

The points in time at which the respective partial movements for the withdrawal movement are completed can also differ.

Alternatively, it can be provided that the retraction movement takes place strictly in the direction of the retraction path 54 . In other words, the movement in the direction of the retreat path 54 can be vectorially limited to the portion of the maximum dynamic range remaining due to the movement along the transfer path 50, 52. The components of the speed vector for the retraction movement resulting from the difference between the speed along the movement path 56, 58 and the speed along the transfer path 50, 52 therefore always have the same ratios as the components of the retraction path 54. The same can also apply to the accelerations .

In summary, the invention relates to a method for moving a processing head of a beam tool between a processing end position of a previous processing phase and a starting position for a subsequent processing phase. A transfer path is specified, which enables the corresponding movement of the processing head without collisions, provided that a workpiece to be processed has negligible tolerances. In order to reliably avoid collisions between the machining head and the workpiece even if the workpiece has finite tolerances in practice, a retraction distance is specified. A movement path for the machining head is calculated from the transfer path and the retraction path, which—at least at the beginning—has both parts of a transfer movement along the transfer path and a retraction movement in the direction of the retraction path. Starting from the machining end position, the movement path is therefore increasingly removed from the transfer path in the direction of the retraction path. In other words, the withdrawal movement and the transfer movement take place simultaneously. The movement path is calculated in such a way that the dynamic limitations of the blasting tool are observed.

Reference List

10

blasting tool

12

processing head

14, 16

workpiece

18

jet

20

workpiece table

22, 24, 26

machine axis

28

control device

30, 32, 34

cutting line

36, 38, 40

edit path

42, 44

Machining end position (actual value)

42'

Machining end position (set value)

46, 48

starting position

50, 52

transfer path

54

retreat distance

56, 58

movement path

t1

time

v_max

maximum speed

v_res

reserve speed

v_perm

allowable speed

f_r

retreat speed

102

Given a transfer path 50.52

104

Given a retreat distance 54

106

Calculating a movement path 56, 58

108

Moving the processing head 12 along the movement path 56, 58

110

Machining the workpieces 14, 16

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2012/104053 A1 [0002, 0004, 0007]
• EP 3062959 B1 [0004]
• EP 3265267 B1 [0004]
• JP 2008200712 A [0006]

Claims (15)

Method for moving a machining head (12), which can be moved along a plurality of machine axes (22, 24, 26) with maximum dynamics, of a blasting tool (10) during a machining pause, the method having the following steps: A) Specification (102) of a transfer path (52, 54) for the machining head (12) starting from a machining end position (42, 44, 42') on a workpiece (14, 16), B) specifying (104) a retreat path (54), C) Calculation (106) of a movement path (56, 58) taking into account the maximum dynamics, the movement path (56, 58) being increasingly shifted in the direction of the retreat path (54) compared to the transfer path (50, 52), D) moving (108) the processing head (12) starting from the processing end position (42, 44) along the movement path (56, 58). procedure after claim 1 , characterized in that a length and/or a direction of the retreat section (54) are specified. Procedure according to one of Claims 1 until 2 , characterized in that the retreat distance (54) is specified by an operator. Procedure according to one of Claims 1 until 2 , characterized in that the retreat distance (54) is automatically determined by a control device (28) of the blasting tool (10), in particular using workpiece data and/or properties of the blasting tool (10). Method according to one of the preceding claims, characterized in that when calculating the movement path (56, 58) the retraction distance (54) is only taken into account to the extent that when the machining head (12) moves along the movement path (56, 58) the end of the transfer path (50, 52) has not been reached. Procedure according to one of Claims 1 until 5 , characterized in that the retreat distance (54) relative to a target value of the machining end position (42 ') is specified. Procedure according to one of Claims 1 until 5 , characterized in that the retreat distance (54) relative to an actual value of the machining end position (42, 44) is specified. Method according to one of the preceding claims, characterized in that when calculating the movement path (56, 58) a speed for the processing head (12) along the transfer path (50, 52) is slowed down to such an extent that the maximum dynamic is maintained. Method according to one of the preceding claims, characterized in that when specifying the transfer path (50, 52) a dynamic reserve for maximum dynamics of the blasting tool (10) is set up, which is preferably available over the entire transfer path (50, 52). procedure after claim 9 , characterized in that when the movement path (56, 58) is calculated, the dynamic reserve is used to set a speed for the machining head (12) in the direction of the retraction path (54). Procedure according to one of Claims 1 until 10 , characterized in that when the movement path (56, 58) is calculated, the movement in the direction of the retreat path (54) is limited overall to the portion of the maximum dynamics remaining due to the movement along the transfer path (50, 52). Procedure according to one of Claims 1 until 10 , characterized in that when the movement path (56, 58) is calculated, the movement in the direction of the retraction path (54) in the machine axes (22, 24, 26) involved is reduced to the proportion remaining in each case as a result of the movement along the transfer path (50, 52). is limited at the maximum dynamic. Method according to one of the preceding claims, characterized in that a plurality of transfer paths (50, 52) for the processing head (12) are specified, each starting from an associated processing end position (42, 44, 42'), that using the same retraction path (54) in each case a movement path (56, 58) is calculated taking into account the maximum dynamics, the respective movement path (56, 58) being increasingly shifted in the direction of the retraction path (54) compared to the associated transfer path (50, 52), and that the processing head (12) starting from the machining end positions (42, 44) along the respective movement paths (56, 58). Computer program comprising program commands which, when the computer program is executed on a control device (28) for a blasting tool (10) with a machining head (12) movable along a plurality of machine axes (22, 24, 46) with maximum dynamics Cause control device (28) to step C) of a method according to one of Claims 1 until 13 to perform. Beam tool (10) with a machining head (12) which can be moved along a plurality of machine axes (22, 24, 46) with maximum dynamics and a control device (28) which is set up to carry out step C) of a method according to one of the Claims 1 until 13 to perform.

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