Method, suction device, suction system and cutting machine for sucking particles, in particular when cutting individual printed circuit boards from circuit board panel

Abstract

The invention relates to a method for sucking particles (40) during the cutting of workpieces (11) from a sheet material, in particular during the cutting of individual printed circuit boards (12) from a circuit board panel (14), and to a suction device (28), a suction system (20) and a cutting machine (10), when the workpiece (11) is cut out and when particles (40) produced during the cutting are drawn out, a compressed air flow (46a, 46b, 46c) pulsated at a pulse frequency is directed to the workpiece such that particles (40) adhering to the workpiece (11) are separated and / or the workpiece (11) begins to vibrate due to the pulsated compressed air flow (46a, 46b, 46c) of the impact.

Description

Technical Field

[0001] The present invention relates to a method for extracting particles when cutting workpieces from a sheet material, in particular when cutting individual printed circuit boards from a circuit board panel (circuit board panel). The present invention also relates to a suction device, a suction system having such a suction device, and a cutting machine for cutting workpieces from a sheet material using such a suction system and / or such a suction device. Background Art

[0002] When using industrial automation systems, the use of efficient and precise manufacturing technology is a basic requirement. An important process step in the production of electronic components is the cutting of sheets of circuit boards into individual components, i.e. into individual printed circuit boards after being populated with components and then soldered. In view of the complexity of today's components and circuit structures, the resulting contamination and contamination of components and printed circuit boards by particles and dust is extremely critical. This not only reduces production yields in electronics manufacturing; undetected errors in components can have far-reaching consequences for product safety. It is therefore particularly important to capture and separate particles and dust as completely as possible when processing sheets of circuit boards and printed circuit boards.

[0003] It is known to extract the particles generated during machining directly from the milling or cutting head using a suction system. However, very small particles can adhere to the workpiece and are not captured and separated by the vacuum of the suction system. These deposits can cause unwanted short circuits in particular between the connections of the electronic components of the individual assemblies.

[0004] From an environmental point of view, it is also important to minimize the release of pollutants into the indoor air. If the particles produced are inhaled, they can harm the health of the operator of the sheet cutter or cutting machine. Respiratory damage and absorption of toxins into the body can result.

[0005] Studies have also shown that the resulting grinding particles are highly abrasive and lead to severe wear of components in the cutting machine. If the dust particles are not removed adequately, they are not only deposited on the workpiece, but also on the entire cutting machine. This in turn leads to damage and higher costs due to wear and maintenance of the cutting machine. The result is malfunctions and deviations from tolerances. The quality of the batch-machined workpieces may be poor and cannot be further used for the final product.

[0006] DE 101 52 401 A1 discloses a milling machine having a chip extraction housing on the milling cutter.

[0007] DE 10 2018 211 278 A1 discloses a suction device for a processing device, in particular a processing device, having a compressed air channel which is configured to form a compressed air flow in the direction of the area to be cleaned. Summary of the invention

[0008] The object of the invention is to increase the process reliability when cutting workpieces, in particular when cutting individual printed circuit boards from a circuit board panel.

[0009] This object is achieved by a method for extracting particles when cutting workpieces from a sheet material, in particular when cutting individual printed circuit boards from a circuit board panel, according to claim 1. Thus, in particular, when cutting the workpiece and when extracting particles generated during cutting, a compressed air flow pulsating at a pulse frequency is directed to the workpiece so that particles adhering to the workpiece are detached and / or the workpiece is set into vibration due to the impacting pulsating compressed air flow.

[0010] This has the following advantages: On the one hand, the particles can be directly separated from the printed circuit board by the pulsating compressed air flow, and on the other hand, the printed circuit board can be set to vibrate by the pulsating compressed air flow, wherein adhering particles, in particular dust and / or debris, are separated from the workpiece. The vibration of the workpiece also reduces the sedimentation of particles that have not yet been sucked off the workpiece. Therefore, the suction according to the method of the invention ensures that the end product is at least largely and ideally completely free of particles and dust, thereby increasing process reliability.

[0011] In particular, the previously known suction systems of the prior art do not capture very small particles because of the suction power, i.e. the possible vacuum or volume flow rate generated is insufficient and cannot be increased indefinitely. For particles with a particle size in the range of 40 μm to 80 μm, in particular particles smaller than 40 μm, adhesion to the workpiece is dominant when they are produced from the cutting of individual components from a sheet of a circuit board. The adhesion of these particles is caused in particular by the electrostatic charging of the particles, whereby adhesion forces act between the particles and the printed circuit board and / or the components. These particles can only be mechanically removed from the electrical components using conventional methods such as moving brushes. This creates the risk of damage or tearing of the usually small and sensitive components mounted and soldered on the printed circuit board. The method according to the invention allows the removal of particles larger than 80 μm from the surface of the printed circuit board in a safe manner during the suction process and reduces the particle deposition caused by vibrations of the printed circuit board. In addition, the particle load inside the cutting machine is reduced, in particular on the processing area and the cutting tool, which leads to a longer service life, longer cleaning and maintenance intervals, and thus reduces the costs of the manufacturing process.

[0012] It has been found that it is advantageous if the pulse frequency is in the range of 1 Hz-60 Hz, in particular 20 Hz-40 Hz, and further in particular 30 Hz. With these frequencies, particles can be removed from the tool and the printed circuit board, and the circuit board can be optimally stimulated to vibrate by the compressed air flow without the components located thereon being damaged or detached due to the vibrations.

[0013] It is conceivable that the pulse frequency is predetermined or settable and that the pulse frequency is adjustable depending on the workpiece parameters. In order to simplify the method, the pulse frequency can be predetermined and controlled within a certain range. For other applications, such as when cutting different printed circuit boards one after another, the pulse frequency can be adjustable. Advantageously and in order to further increase process reliability, the pulse frequency can be adjusted depending on the workpiece parameters. This can be done, for example, manually or using a database in which the workpiece parameters are stored.

[0014] Furthermore, it is advantageous if the vibration frequency of the workpiece is measured during the suction process and if the pulse frequency is adjusted as a function of the vibration frequency. This is an advantageous development of the aforementioned aspect, since by controlling the pulse frequency of the compressed air flow, the vibration frequency of the workpiece can always be kept within a safe range for particle separation. This can further increase process reliability.

[0015] It is also conceivable to measure the vibration frequency of the workpiece by means of an optical camera or a vibration sensor. A camera is usually already present in the cutting machine to detect the circuit board panel to be cut. The generated image can also be used to determine the vibration frequency. If the vibration amplitude of the vibrating circuit board panel is too small and cannot be detected by the camera, it is advantageous to provide a vibration sensor for reliably measuring the vibration amount.

[0016] It is also advantageous if the compressed air forming the compressed air flow is ionized. During the cutting process, electrostatic potentials are generated by the friction of the cutting tool, in particular a milling cutter or a saw. Due to the electrostatic potentials, the particles adhere more firmly to the circuit board panel. In order to avoid this, the electrostatic potential of the particles must be reduced. By means of ionized molecules in the compressed air, the electrostatic potential, in particular of the particles, can be reduced or balanced and the particles can be released more easily from the circuit board panel, the printed circuit board and the components of the cutting head.

[0017] It can further be provided that the compressed air flow is generated by at least one and preferably three compressed air nozzles in the suction opening extending around the central axis and forms a vortex around the central axis. The formation of the vortex further increases the particle separation effect.

[0018] It has also proven to be advantageous if the volume flow of the air sucked out, including the particles, is greater than the compressed air flow blown in. This ensures that the vacuum that leads to the suction of the particles can be applied in a safe process.

[0019] The purpose mentioned at the beginning is also achieved by a suction device, which is used to suck out particles when cutting workpieces from a sheet material, in particular when cutting a single printed circuit board from a circuit board panel, and is also particularly used to implement the method according to the invention. The suction device provides a suction opening extending around a central axis and at least one compressed air nozzle, which is arranged to generate a compressed air flow guided in the direction of the main air flow. The compressed air nozzle is particularly arranged in the suction opening so that the main air flow direction is guided toward the workpiece to be cut. In addition, a compressed air pipeline is provided to supply compressed air to the compressed air nozzle. A valve unit is arranged in the compressed air pipeline, which is configured to generate a compressed air flow pulsating at a pulse frequency, so that particles adhering to the workpiece are separated, and / or the workpiece is vibrated due to the impact of the pulsating compressed air flow. This can further improve process reliability.

[0020] It can also be further proposed that the valve unit is designed as an electrically controlled switching valve, and the control unit is configured to actuate the switching valve to generate a pulse frequency. This has the advantage that the switching valve can be actuated simply and the method according to the invention can be integrated into a commercially available control system or machine control system.

[0021] It has also proven to be advantageous if the switching valve is actuated by the control unit with a pulse frequency in the range of 1 Hz-60 Hz, in particular in the range of 20 Hz-40 Hz, further in particular at 30 Hz. Advantageously, the pulse frequency of the compressed air flow is transmitted to the workpiece, which then vibrates to detach the adhering particles.

[0022] It is also conceivable that the control unit is configured to control the switching valve as a function of the workpiece parameters and / or to adjust the switching valve as a function of the measured vibration frequency. This is advantageous because it ensures even higher process reliability by maintaining tolerances on the vibration frequency.

[0023] An ionizer may also be provided for ionizing the compressed air forming the compressed air flow. This allows the ionized compressed air to be generated in the vicinity of the cutting machine to ensure the best possible ionization of the air molecules used to form the compressed air. It is therefore advantageous if at least one compressed air nozzle is made of a non-conductive material, in particular a non-conductive plastic material. The non-conductive plastic material advantageously maintains the ionized state of the air molecules and does not compensate for the ionization of the air molecules until the compressed air of the compressed air flow impacts the workpiece or the particles to be removed.

[0024] Furthermore, a nozzle ring forming the suction openings can be provided, on which at least one compressed air nozzle and preferably three compressed air nozzles are arranged at an angular distance of 120° from one another. With three compressed air nozzles, a favorable quality of compressed air can be directed onto the workpiece via the compressed air stream. The arrangement of the compressed air nozzles on the component facilitates installation on the cutting machine.

[0025] Advantageously, the main air flow direction of the at least one compressed air nozzle is operated in such a way that during operation the compressed air flow generates a vortex about the central axis.

[0026] It can further be provided that the nozzle ring has a circular outer contour with a flat point, wherein one or more compressed air connections are provided at the flat point.

[0027] It is also advantageous if the nozzle ring has a circumferential shoulder with a shoulder edge around the suction opening on the upper side facing the suction opening and if at least one compressed air nozzle is arranged on the shoulder edge. This has the advantage that the arrangement of the compressed air nozzle on the shoulder edge has little interference with the compressed air flow emerging from the compressed air nozzle and this can be developed in the best possible way.

[0028] The nozzle ring can have an upper side facing the suction opening and a lower side facing away from the suction opening, wherein the upper side and the lower side are parallel to one another.

[0029] It is also conceivable that the nozzle ring has a sensor holder for a tool sensor, wherein a sensor nozzle is arranged facing the sensor holder. The sensor is particularly configured to detect wear or breakage of the cutting tool. Due to the deposition of particles, the function of the sensor may be limited, as this may be particularly the case with optical sensors. The sensor nozzle is advantageously configured to blow away the deposited particles on the sensor with compressed air.

[0030] The objects mentioned at the outset are also achieved by a suction system having a vacuum source, a vacuum line for connecting a suction device to the vacuum source, and an adjusting device for adjusting the vacuum line to a movable position of the suction device, wherein the suction device is operated according to the suction device according to the invention and / or according to the method according to the invention. Advantageously, the suction device and the method according to the invention are adapted to one another in such a way that the suction function is optimal and all components interact with one another. This leads to an increase in process reliability.

[0031] The objects mentioned at the outset are also achieved by a cutting machine for cutting workpieces from a circuit board panel, in particular cutting individual printed circuit boards from a circuit board panel, comprising a cutting head, a central control unit, and a suction system of a suction device according to the invention. The suction device is operated in particular by the method according to the invention, wherein the control unit is also particularly configured to actuate the cutting head and the valve unit of the suction device in parallel.

[0032] Further details and advantageous designs of the invention can be found in the following description, on the basis of which embodiments of the invention are described and explained in more detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A cutting machine for cutting printed circuit boards from a circuit board panel using a suction system having a suction device; Figure 2 yes Figure 1 A schematic cross-sectional view of a suction device; Figure 3 yes Figure 1 A nozzle ring of a suction device; Figure 4 yes Figure 3 A plan view of the nozzle ring; Figure 5 yes Figure 4 a side view of a nozzle ring; and Figure 6 yes Figure 1 View of the cutting machine entering the suction opening obliquely from above. DETAILED DESCRIPTION

[0034] exist Figure 1 In FIG. 1 , a cutting machine 10 for cutting workpieces 11 from a sheet material, ie for cutting printed circuit boards 12 from a plate-like printed circuit board panel 14 is shown.

[0035] The cutting machine 10 includes a cutting head 16, a central control unit 17 (such as Figure 2 ) and a suction system 20. For the sake of clarity, the axis drives for moving the cutting head 16 and other components of the cutting machine 10 are not shown.

[0036] The cutting head 16 has a drive 18 and a cutting tool 19 , such as a milling cutter, for cutting the printed circuit board 12 out of the printed circuit board panel 14 .

[0037] The suction system 20 comprises a vacuum source 22 and a vacuum line 24 having a connection 26 to a suction device 28 arranged on the cutting head 16. Furthermore, an adjustment device 30 is shown for adapting the vacuum line 24 to the position of the suction device 28 so as to be able to follow the variable position of the movable cutting head 16. Preferably, a plurality of adjustment devices (not shown) are provided to adapt the vacuum line 24 in all directions of movement of the cutting head 16.

[0038] like Figure 2 As shown, the suction device 28 comprises an annular nozzle ring 32 and a brush ring 34 arranged on the nozzle ring 32. The nozzle ring 32 forms a suction opening 36 around a central axis 38. Figure 6 A view into the suction opening 36 from obliquely above is shown. Figure 6 As shown, the brush ring 34 or its bristles are located on the circuit board panel 14 and / or on the printed circuit board 12 when the circuit board 12 is cut.

[0039] exist Figure 2 In the drawing, a suction device 28 with a nozzle ring 32 is schematically simplified as a cross-section around a cutting head 16. A drive 18 of the cutting head 16, designed, for example, as an electric motor or a pneumatic motor, drives a cutting tool 19. The cutting tool 19 processes the circuit board panel 14 and cuts out individual printed circuit boards 26. When cutting, particles 40 such as dust and / or debris appear. In addition, Figure 2 It is shown that particles 40 generated during the processing of the circuit board panel 14 are sucked through the suction openings 36 into a suction air volume indicated by arrows 42 due to the vacuum generated by the vacuum source 22 .

[0040] The nozzle ring 32 has a total of three compressed air nozzles 44a, 44b and 44c. Figure 3 As shown, due to the cross-sectional view, Figure 2 Only two compressed air nozzles 44a and 44b are shown in FIG. The compressed air nozzles 44a, 44b and 44c form compressed air flows 46a, 46b and 46c respectively along main air flow directions 48a, 48b and 46c towards the printed circuit board 12 and / or the circuit board panel 14.

[0041] also, Figure 2 Schematically shown in FIG. 1 is an electric switching valve 50 having two compressed air connections 52 and 54. The compressed air connection 52 is connected to a compressed air source 56 and an air ionizer 58. The compressed air connection 54 is connected to a compressed air line 60 which connects the switching valve 50 to the compressed air nozzles 44a, 44b and 44c in the nozzle ring 32.

[0042] The switching valve 50 is designed as an electric fast switching valve and has an interface 62. The switching valve 50 is connected to the central control unit 17 of the cutting machine 10 via the interface 62. The control unit 17 controls the switching valve 50 so that the switching valve 50 affects the compressed air, which comes from the compressed air source 56 and is advantageously ionized, and finally forms the compressed air streams 46a, 46b and 46c, so that the compressed air streams 46a, 46b and 46c discharged from the compressed air nozzles 44a, 44b and 44c are pulsated. The switching valve 50 is actuated by the control unit 17, in particular in a manner such that the pulse frequency is within the range of 1Hz-60Hz. The pulse frequency can advantageously be variably adjusted to the workpiece parameters of the circuit board panel 14.

[0043] Due to the pulsating compressed air streams 46a, 46b and 46c, the printed circuit board panel 14 is advantageously vibrated and particles 40, such as debris and / or dust, deposited thereon are dislodged or shaken off so that the separated particles 40 can be sucked out.

[0044] Figure 2 The sensor 64 shown for recording the vibration frequency of the circuit board panel 14 is coupled to the circuit board panel 14 and is connected to the control unit 17. By using the vibration frequency of the printed circuit board panel 14 as a measured variable, the vibration frequency of the printed circuit board 12 can be adjusted by the control unit 17. In addition, the control unit 17 is also connected in particular to the drive 18 of the cutting head 16 and controls this drive during the cutting process in parallel with the switching valve 50 and other machine functions of the cutting machine 10.

[0045] During the cutting process, the brush ring 34 bears against the circuit board panel 14 and / or printed circuit board 12 to be cut and seals the suction opening 36 from the environment 66, so that the vacuum extends to the circuit board panel 14. This makes it particularly easy to capture and suck out particles 40. Advantageously, the brush ring 34 is sealed by the suction opening 36 and the environment 66. Figure 2 The air volume flow sucked out by the vacuum source 22 and indicated by the arrow 42 in FIG. 1 is at least as great as the volume of the particles 40 produced and separated and the volume of the compressed air flows 46 a , 46 b and 46 c blown in.

[0046] Figure 3 , Figure 4 and Figure 5 Shows Figure 1 and Figure 2. The nozzle ring 32 has an annular base body which forms a suction opening 36 around a center axis 38. An upper side 70 faces the suction opening 36 parallel to a lower side 72 at a distance d below. Furthermore, the nozzle ring 32 has a flat spot 74 on an outer contour 76, at which two compressed air connections 78 and 80 are located. Furthermore, the nozzle ring 32 has three compressed air nozzles 44a, 44b and 44c which are connected to the compressed air connection 78. The compressed air connection 78 is connected to the switching valve 50 during operation.

[0047] On the upper side 70, the nozzle ring 32 also has a circumferential shoulder 82 with a shoulder edge 84 surrounding the suction opening 36. Three compressed air nozzles 44a, 44b and 44c are arranged on the shoulder edge 84 at an angular distance a of 120° from one another.

[0048] The compressed air nozzles 44a, 44b and 44c are designed in such a way that they direct the compressed air flows 46a, 46b and 46c emerging from them in an associated main air flow direction 48a, 48b or 48c, each of which is indicated by an arrow. The compressed air flows 46a, 46b and 46c are directed onto the circuit board panel 14 and / or the printed circuit board 12 in such a way that they form a vortex around the center axis 38. The main air flow directions 48a, 48b and 48c do not extend parallel to the center axis 38, but rather extend obliquely. Figure 4 As can be seen in FIG. 1 , the main air flow directions 48a, 48b and 48c in the plan view preferably enclose an angle β in the range of 45° to 90° with the relevant tangent lines 49a, 49b and 49c contacting the shoulder edge 84. The relevant tangent lines 49a, 49b and 49c are located at the center of the compressed air nozzles 44a, 44b and 44c belonging to the main air flow direction 48a, 48b or 48c on the shoulder edge 84. In the vertical direction, as Figure 5 As shown, the main air flow directions 48a, 48b and 48c in the side view of the relevant compressed air nozzles 44a, 44b and 44c form an angle with the central axis 38γ in the range of 0° to 30°. Figure 5 Only the compressed air nozzle 44b, the compressed air flow 46b and the main air flow direction 48b are shown in FIG. During operation of the suction device 28, the compressed air flows 46a, 46b and 46c are swirled around the central axis 38 by combining the arrangement of the compressed air nozzles 44a, 44b and 44c at an angle α with the formation of the main air flow directions 48a, 48b and 48c in the direction of the two angles β and γ.

[0049] Furthermore, the nozzle ring 32 has locating holes 86 which are arranged to easily achieve the correct mounting position when the nozzle ring 22 is arranged on the cutting head 16 during replacement and / or maintenance. The locating holes 86 ensure that the compressed air nozzles 44a, 44b and 44c point in the direction of the cutting tool 19 during operation.

[0050] Furthermore, a hole 88 is provided for mounting the brush ring 34 on the nozzle ring 32. For this purpose, a thread can be provided in the hole 88.

[0051] Furthermore, a sensor nozzle (not shown) connected to a compressed air connection 80 is provided, as well as a sensor holder (not shown) for a tool sensor (not shown); the tool sensor can be optical, for example. Using an optical tool sensor connected to the control unit 17, damage, breakage or wear of the cutting tool 19 can be detected during operation of the cutting machine 10. The state of the cutting tool 19 can be signaled to the operator, or further automated processes can be performed by the control unit 17 to ensure process reliability. The sensor nozzle is provided to blow off any deposited particles 40 from the tool sensor using compressed air in order to ensure the proper operation of the sensor. The compressed air can also be pulsed and supplied by the switching valve 50 via the compressed air line 60.

[0052] The nozzle ring 32 is preferably made of a non-conductive plastic material, and is preferably additively manufactured. If the nozzle ring 32 is made of a non-conductive plastic material, the compressed air ionized by the ionizer 58 remains ionized. As a result, the compressed air can further improve the separation of particles 40 that adhere to the printed circuit board panel 14 and / or the printed circuit board 12 or other machine parts due to static electricity.

[0053] Figure 6 A view of a cutting machine 10 is shown entering a suction opening 36 of a suction device 28. The cutting tool 19 of the cutting head 16 is located on the center axis 38 of the suction opening 36, wherein the suction opening 36 is surrounded by a nozzle ring 32. A brush ring 34 is arranged on the nozzle ring 32. The brush ring 34 is designed to be height-adjustable.

[0054] The particles 40 in the cutter 10 are sucked out as follows: The air is compressed by a compressed air source 56 into compressed air, ionized by an ionizer 58 and fed to a compressed air line 60 .

[0055] The electric switching valve 50 is actuated by the control unit 17 such that the outgoing compressed air is pulsated with a pulse frequency of, in particular, 1 Hz-60 Hz.

[0056] The compressed air nozzles 44a, 44b and 44c in the nozzle ring 32 each form a pulsating compressed air flow 46a, 46b and 46c from the pulsating compressed air.

[0057] The pulsating compressed air flows 46a, 46b and 46c are directed along relevant main air flow directions 48a, 48b and 48c onto the circuit board panel 14 and / or the printed circuit board 12. By appropriately selecting the relevant main air flow directions 48a, 48b and 48c, a vortex is formed around the central axis 38 of the suction opening 36.

[0058] Due to the pulsations of the compressed air streams 46a, 46b and 46c impinging on the circuit board panel 14 and / or the printed circuit board 12, the particles 40 are detached from the circuit board panel 14 and / or the printed circuit board 12. The detachment of the particles 40 is advantageously supported by the eddy currents formed.

[0059] The pulse frequency of the pulsating compressed air streams 46a, 46b and 46c that impinge on the circuit board panel 14 and / or the printed circuit board 12 can be transmitted to the circuit board panel 14 and / or the printed circuit board 12 and cause the circuit board panel 14 and / or the printed circuit board 12 to vibrate. As a result, when the adhering particles 40 are shaken off, they are peeled off by electrostatic forces. The ionized state of the compressed air further ensures a reduction in electrostatic forces and promotes the separation of very small adhering particles 40.

[0060] By means of the applied vacuum 42, the separated particles 40 and the volume of the blown-in compressed air streams 46a, 46b and 46c are sucked out.

Claims

1. A method for extracting particles (40) when cutting workpieces (11) from sheet metal, in particular when cutting individual printed circuit boards (12) from a circuit board panel (14), characterized in that: In order to cut out the workpiece (11) and when sucking out the particles (40) generated during cutting, a compressed air flow (46a, 46b, 46c) pulsating at a pulse frequency is directed to the workpiece, so that the particles (40) adhering to the workpiece (11) are detached, and / or the workpiece (11) begins to vibrate due to the impact of the pulsating compressed air flow (46a, 46b, 46c).

2. The method according to claim 1, characterized in that The pulse frequency is in the range of 1 Hz-60 Hz, in particular in the range of 20 Hz-40 Hz, and further in particular 30 Hz.

3. A method according to any one of the preceding claims, wherein: The pulse frequency is predetermined or adjustable, and the pulse frequency is adjustable as a function of workpiece parameters.

4. The method according to any one of the preceding claims, characterized in that During the suction process, the vibration frequency of the workpiece (11) is measured, and the pulse frequency is adjusted according to the vibration frequency.

5. The method according to claim 4, characterized in that The vibration frequency of the workpiece (11) is measured by an optical camera or a vibration sensor (64).

6. The method according to any one of the preceding claims, characterized in that The compressed air forming the compressed air flow (46a, 46b, 46c) is ionized.

7. The method according to any one of the preceding claims, characterized in that The compressed air flow (46a, 46b, 46c) is generated by at least one, preferably three, nozzles (44a, 44b, 44c) in a suction opening (36) extending around a central axis (38) and forms a vortex around the central axis (38).

8. The method according to any one of the preceding claims, characterized in that The volume flow (40) of air sucked out and containing particles is greater than the volume flow (46a, 46b, 46c) of compressed air blown in.

9. A suction device (28) for extracting particles (40) when cutting workpieces (11) from sheet materials, in particular when cutting individual printed circuit boards (12) from a circuit board panel (14), and also in particular for carrying out the method according to one of the preceding claims, the suction device (28) comprising: a suction opening (36) extending about a central axis (38), at least one compressed air nozzle (44a, 44b, 44c), which is arranged to generate a compressed air flow (46a, 46b, 46c) directed in a main air flow direction (48a, 48b, 48b), It is characterized in that The compressed air nozzles (44a, 44b, 44c) are arranged in the suction opening (36) in such a way that the main air flow direction (48a, 48b, 48c) is directed towards the workpiece (11) to be cut, A compressed air pipeline (60) is provided, wherein the compressed air pipeline (60) is used to provide compressed air to the compressed air nozzles (48a, 48b, 48b), and wherein a valve unit (50) is disposed in the compressed air pipeline (60) and is configured to generate a compressed air flow (46a, 46b, 46c) pulsating at a pulse frequency so as to separate particles (40) adhering to the workpiece (11), and / or In this case, the workpiece (11) begins to vibrate due to the impacting, pulsating compressed air flow (46a, 46b, 46c).

10. The suction device (28) according to claim 9, characterized in that The valve unit (50) is designed as an electrically controlled switching valve, and a control unit (17) is provided therein for actuating the switching valve (50) to generate the pulse frequency.

11. The suction device (28) according to any one of claims 9 or 10, characterized in that The switching valve (50) is actuated by the control unit (17) such that the pulse frequency is in the range of 1 Hz-60 Hz, in particular in the range of 20 Hz-40 Hz, and further in particular 30 Hz.

12. The suction device (28) according to any one of claims 9 to 11, characterized in that The control unit (17) is configured to control the switching valve (50) according to workpiece parameters and / or to adjust the switching valve (50) according to the measured vibration frequency.

13. The suction device (28) according to any one of claims 9 to 12, characterized in that An ionizer (58) is provided for ionizing the compressed air forming the compressed air flow (46a, 46b, 46c).

14. The suction device (28) according to any one of claims 9 to 13, characterized in that A nozzle ring (32) is provided which forms the suction opening (36), on which the at least one compressed air nozzle (44a, 44b, 44c) and preferably three compressed air nozzles (44a, 44b, 44c) are arranged at a distance of 120° from one another.

15. The suction device (28) according to any one of claims 9 to 14, characterized in that The nozzle ring (32) has, on an upper side (70) facing the suction opening, a circumferential shoulder (82) surrounding the suction opening (36), the circumferential shoulder (82) having a shoulder edge (84), and the at least one compressed air nozzle (44a, 44b, 44b) is arranged on the shoulder edge (84).

16. The suction device (28) according to any one of claims 9 to 15, characterized in that The nozzle ring (32) has a sensor holder for a tool sensor, wherein a sensor nozzle is provided pointing toward the sensor holder.

17. A suction system (20) comprising a vacuum source (22), a vacuum line (24) for connecting (26) a suction device (28) to the vacuum source (22), and an adjustment device (30) for adjusting the vacuum line (24) to a movable position of the suction device (28), wherein: The suction device (28) is operated according to a suction device (28) according to any one of claims 9-16 and / or according to a method according to any one of claims 1-9.

18. A cutting machine (10) for cutting workpieces (11) from sheet materials, in particular for cutting individual printed circuit boards (12) from circuit board panels (14), the cutting machine (10) comprising a cutting head (16), a central control unit (17) and a suction system (20) according to claim 17 and a suction device (28) according to any one of claims 9 to 16, which is operated according to the method according to any one of claims 1 to 9, wherein: The control unit (17) is configured to control the cutting head (16) and the valve unit (50) of the suction device (28) in parallel.

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