EP3678805A1

EP3678805A1 - Laser machine tool having suction system

Info

Publication number: EP3678805A1
Application number: EP18766235.8A
Authority: EP
Inventors: Martin Reisacher; Andreas Abt
Original assignee: Sauer GmbH and Co KG
Current assignee: DMG Mori Ultrasonic Lasertec GmbH
Priority date: 2017-09-08
Filing date: 2018-09-07
Publication date: 2020-07-15
Also published as: JP2020533483A; CN111356545B; US11376690B2; WO2019048613A1; KR20200055738A; KR102485713B1; CN111356545A; JP7265534B2; US20200298338A1; DE102017215911A1

Abstract

The present invention relates to a machine (1) for machining workpieces and/or for producing moulded bodies by location-selective solidification of material powder (P) to form connected regions by means of a focused laser beam (L). The machine (1) comprises a process chamber (10) which can be closed by a process chamber door (11) and which encloses a process space (12), a material powder container cabinet (7), which can be closed by a door, for storing material powder (P), and a suction system. The suction system has a fan (2) for generating an air flow, a first suction apparatus fluidically connected to the fan (2) by means of a first waste air duct (3a) to suction particles out of the process space (12), and a second suction apparatus fluidically connected to the fan (2) by means of a second waste air duct (3b) to suction particles out of the material powder container cabinet (7). According to the invention, the first suction apparatus has means (4a) for controlling a suction power of the first suction apparatus and/or the second suction apparatus has means (4b) for controlling a suction power of the second suction apparatus.

Description

Laser machine tool with extraction system

description

The present invention relates to a machine for processing workpieces and / or for producing moldings by locally solidifying material powder to coherent areas by means of a focused laser beam, the machine having a suction system for sucking off particles.

The present invention also relates to a method for aspirating particles from a process space in a process chamber of a machine chamber closable by a process chamber for processing workpieces and / or for producing moldings by locally solidifying material powder to coherent areas by means of a focused laser beam.

background

A generic machine is in particular a machine for producing shaped articles according to the principle of selective laser melting, selective laser sintering or laser deposition welding. In particular material powder made of metal, plastic or ceramic can be used. In summary, for the various types of machines for processing / manufacturing / producing a workpiece or a shaped body with a laser beam, the term laser machine tool or simply a machine is used below.

With the method of selective laser melting, laser sintering or laser deposition welding molded body, such as machine parts, tools, prostheses, jewelry, etc., according to Geometriebeschreibungsdaten the corresponding moldings, for example, by layering of a metallic or ceramic material powder or a plastic powder produced or processed. In the manufacturing process, the material powder is passed by means of a powder nozzle to the focal point of a focused laser beam, heated by the focused laser beam, so that the material powder is remelted in the irradiated areas to coherently solidified sections. After cooling, a layer of material is created, which can be processed mechanically.

210185 PC The prior art relating to the field of selective laser melting, for example, reference is made to DE 10 2015 522 689 AI. Furthermore, a laser machine tool of the type mentioned in the introduction is known for example from EP 2 052 845 A2. A machine tool for build-up welding is described, for example, in the published patent application DE 10 2013 224 649 A1.

The article "Laser unit makes build-up welding on machining center possible" by Nowotny et al. in "MM Das Industriemagazin", 17/2009, page 42 ff., describes a laser processing optics, which is used via a steep taper in the milling spindle of a CNC machine. In the laser focal point weld metal (material powder) is fed through a powder nozzle. The workpiece can be milled in the same machine.

There are essentially two types of machines for machining workpieces and / or for the production of moldings by locally solidified material from powder to coherent areas by means of a laser beam, in particular by selective laser melting or selective laser sintering or laser deposition welding, known. The types of machines differ, among other things, in the way the material powder is provided. In a first type of machine, a powder bed is built up in layers. In a second type of machine, the material powder is provided by means of a powder nozzle at the point of machining. The present invention particularly relates to machines in which the material powder is provided by means of a powder nozzle at the focal point of the laser. The mechanical structure for moving the laser processing head and / or the workpiece, for example, as in a known five-axis machining center, wherein instead of a mechanical tool, the laser processing head is provided. Machine tools have also been available on the market for some years now, which permit both laser machining and machining, for example with a milling tool. In such hybrid machining centers, the laser processing head can be attached to the recording of the Werkzugspindel.

In the above-mentioned methods, in particular laser deposition welding, welding fumes may be produced, which may be harmful to human health, as they may contain respirable particles which may be carcinogenic, so that a significant health hazard may arise from such particles. Welding fume particles may for example have a size of a few micrometers or even a few tenths of a micron. They are therefore also referred to as fine dust particles. In particular, because of the potential health hazard to humans, an operator of such a machine must be protected from the inhalation of the particles. As a first protective measure, an operator of the

210185PC Machine wear a respirator. However, protection by a mask may be insufficient. In addition, other persons who are in an environment of the machine are not protected. In order to avoid contamination of the ambient air of the machine with health-endangering particles as far as possible, laser machine tools therefore usually have suction devices for extracting the particles from the process space.

As a rule, a laser machine tool has a process chamber which can be closed by a process chamber door and which surrounds a process space. By means of a suction device, a negative pressure can be built up in the process chamber, so that in any case no particles are released into the environment when the process chamber is closed. When operating the suction device, the air flow must be adjusted so that on the one hand as efficient as possible suction of the particles is guaranteed. On the other hand, the airflow generated in the process room must not disturb the process itself. For example, too strong an air stream a material powder flow, which is generated by a flowing through the powder nozzle carrier gas disturb, so that at the focal point of the laser beam no sufficient amount of material powder or an uneven distribution of powder material arrives. In order to avoid a disturbance of the material powder flow, have suction usually a manually adjustable throttle to adjust the suction on. Throttle valve adjustment is typically done once when installing or servicing the machine.

Due to the specified throttling of the suction power, however, after the end of the process it is no longer possible to use the full suction power for extracting the particles from the process space. Thus, it is necessary to wait unnecessarily long before opening the process chamber door until all the air in the process space has been completely replaced at least once, so that contamination of the environment or of the operator of the machine with particles can be largely ruled out. Summary

The present invention is in view of the above, the object to provide a machine with an exhaust system, in which the suction power is adjustable. The object is achieved by a machine according to the preamble of claim 1. According to the invention, the first suction means comprises means for controlling a suction power of the first suction means and / or the second suction means comprises means for controlling a suction power of the second suction means.

210185PC The object is also achieved by a method for extracting particles from a process space in a process chamber of a machine chamber closable by a process chamber for processing workpieces and / or for producing moldings by locally solidifying material powder to contiguous areas by means of a focused laser beam. In a first method step, the process room door is locked before the machine starts a machining process. This ensures that the process room door can not be opened during the machining process. In a further method step, a first suction device for sucking particles out of the process chamber is operated at a reduced power while the machine is performing the machining process. The throttling of the power takes place, for example, depending on the material used powder or as a function of a material powder flow. This prevents that an air stream generated by the suction influences the material powder flow. In a further method step, the first extraction device is operated for extracting particles from the process space at maximum power during a fixed period of time after a processing process is interrupted or terminated. This advantageously makes it possible that all harmful particles or at least a large part of harmful particles can be sucked out of the process space before the process room door can be opened. The period is set so that all the air in the process room is completely replaced at least once during the period. In a final process step, the process room door is unlocked after the specified period has expired. As soon as all particles have been sucked out of the process area, the process room door can be opened again. There is no longer any danger that an operator of the machine or an ambient air of the machine will be contaminated with harmful particles.

The term throttled power refers to a suction power that is less than a maximum suction power. The air stream for suction is generated by a fan, which is preferably operated at a constant power. The suction power of a suction device is then preferably throttled by limiting the air flow, for example by throttle valves. The throttle valves may for example be arranged in exhaust ducts of the suction device, which are flow-connected to the blower.

Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

Preferably, the means for controlling the suction power of the first suction device and / or the second suction device each have actuators. The actuators may preferably be controlled separately from a machine controller. Thus, the

210185PC Extraction of the first suction and / or the suction of the second suction fully automatically and integrated into a process flow can be adjusted. In addition, the suction power can be adjusted depending on a state of the machine.

In a preferred embodiment of the machine, an air inlet and an air outlet connected to the first exhaust air duct are arranged in the process space. The air inlet and the air outlet are preferably arranged such that an air flow is generated over a focal point of the focused laser beam. If the generated air flow flows over the focal point of the laser beam, a generated welding fume can be extracted particularly efficiently, since the welding fume is produced at the focal point or in the immediate vicinity of the focal point of the laser beam. Furthermore, the first suction device can be operated with a lower suction power when the air flow flows past where the welding smoke is produced. The air inlet and the air outlet are in particular arranged so that the air flow is generated in the horizontal direction. Such an arrangement is particularly advantageous when the laser processing head emits the focused laser beam in the vertical direction on the workpiece. The air flow generated in the horizontal direction can then flow unhindered past the workpiece.

It is preferred that the means for controlling the suction power of the first suction device and / or the second suction device are arranged, the suction power of the first suction device and / or the second suction device in dependence on an opening state of the process room door and / or an opening state of the door of the material powder container adjust. With the process chamber door open or with the door of the material powder container open, a higher suction power is required to prevent contamination of the environment by particles. In other words, to maintain a negative pressure in the process space or in the material powder container, a higher suction power is required than when the doors are closed. In particular, the process chamber door can only be opened when the machining process of the machine is ended or interrupted. Thus, the first suction device can be operated at full power with the process chamber door open, without the risk of negatively affecting the powder flow. The machine controller may be configured to lock the process room door as long as a machining process is taking place. After the process has been ended or interrupted, the process room door can, for safety reasons, remain locked for a fixed period of time during which the extraction of the generated welding fumes is carried out. If the suction power is increased, this fixed period can be shortened.

210185PC The means for controlling the suction power of the first suction device and / or the second suction device may be configured to adjust the suction power of the first suction device and / or the second suction device in dependence on a machining and / or manufacturing process of the machine. In particular, the suction power of the first suction device is throttled during a machining and / or manufacturing process, in order to avoid an influence on the material powder flow from the powder nozzle. If the processing and / or manufacturing process is interrupted or completed, then the suction power of the first suction device can be set to the maximum value. The means for controlling the suction power of the first suction device and / or the second suction device may be configured to adjust the suction power of the first suction device and / or the second suction device in dependence on the material material and / or the material material composition of the material powder. Depending on the composition of the material, different welding fumes may be produced when different materials are used, which can be formed differently in terms of composition, pollutant, pollutant or smoke concentration and toxicity of the pollutants contained. Accordingly, this exemplary embodiment has the advantage that the suction power is adjustable as a function of the resulting welding fume, wherein a higher suction power is preferably adjustable for materials with relatively higher pollutant concentration in the welding fume and / or higher toxicity of the pollutants contained and lower for materials Pollutant concentration in the welding fumes and / or lower toxicity of the pollutants contained a lower suction power is adjustable.

The exhaust method may further comprise a step of operating a second exhaust means for exhausting particles from the casing (e.g., a material powder cupboard) for the material powder containers. The suction power of the second suction device can be adjusted depending on whether a door of the housing or the material powder cabinet is open or closed. With the door of the material pulp cabinet (or material powder container cabinet) open, in which one or more material powder containers may be arranged, the second suction means may be operated at full suction, so as to prevent or at least reduce leakage of material powder from the material powder container into the environment. When the door of the material powder cabinet door is closed, the second suction device can be operated at a reduced suction power, since not the full power is required to produce a sufficiently high negative pressure in the material powder cabinet.

210185 PC Brief description of the figures

Further advantageous embodiments will be described in more detail below with reference to an embodiment shown in the drawings, to which the invention is not limited.

They show schematically:

Figure 1: a structure of a machine tool for producing or editing a

Shaped body or workpiece by means of focused laser radiation.

Figure 2: a perspective view of an embodiment of an inventive

Laser machine tool with extraction system.

FIG. 3 shows a detailed view of the exhaust air ducts and throttle valves of the laser

Machine tool according to the embodiment of FIG. 2.

4 shows a perspective view of the process space of a laser machine tool according to an embodiment.

Figure 5: an exemplary timing of the suction.

FIG. 6: an illustration of the principle of action of laser deposition welding.

Detailed description of the invention with reference to an embodiment

In the following description of a preferred embodiment of the present invention, like reference characters designate like or similar components.

Fig. 1 shows a schematic representation of a machine 1 for processing a workpiece and / or for producing a shaped body by location-selective solidification of material powder to coherent areas by means of laser radiation. The machine 1 has a machine frame 21, to which a work table 20 and, on the other hand, a laser processing head 23 with a powder nozzle 15 are attached indirectly via adjusting axles 22 lying therebetween. The adjusting axes 22 may each have a plurality of translatory (X, Y, Z) or rotary (φ, λ, Θ) axes, which are adjustable in accordance with a machine control. The design may, for example, be such that the laser processing head 23 via one, two

210185 PC or three translatory adjusting axes 22 (X and / or Y and / or Z) is fixed to the machine frame 21, while the workpiece table 20 is attached to the machine frame 21 via one, two or three rotary adjusting axes 22. The machine 1 may be, for example, a five-axis laser machine tool for the production of moldings by location-selective solidification of material powder to coherent areas by means of laser radiation. On the workpiece table 20, a workpiece can be releasably secured for editing. Alternatively, a shaped body can be built up in layers on the workpiece table 20 by site-selective solidification of material powder.

Such a laser machine tool 1 generally has a closed process chamber 10 in which a negative pressure can be generated by means of an exhaust system in order to protect an environment of the machine 1 from contamination by welding fumes or other particles, for example material powder. The process chamber 10 surrounds a process space 12, which is accessible via a process room door 11. The process room door 11 may have a locking mechanism that can be actuated depending on the machining process. As a result, it can be prevented that the process chamber door 11 is opened during an ongoing machining process.

The extraction system can suck in air from the process space 12 via an air outlet 5a. The air outlet 5a is fluidly connected to a fan 2 via a first exhaust duct 3a. Via an air inlet 5b, which is flow-connected to a supply air duct 3d, the process space 12 fresh air can be supplied. By a suitable positioning of the air inlet 5b and the air outlet 5a in the process chamber 12, the direction of the air flow F in the process chamber 12 can be adjusted so that the air flow F is substantially horizontally past an operating point of the laser machine tool 1, where a focused laser beam L the supplied through the powder nozzle 15 material powder P merges with the workpiece. The principle of action of laser deposition welding will be described in more detail below with reference to FIG. The air flow F is shown in FIG. 1 as a dotted arrow. Further dotted arrows illustrate a supply air flow through the supply air duct 3d and an exhaust air flow through the first exhaust air duct 3a.

The air inlet 5b may also be omitted in alternative embodiments of the invention. The supply of fresh air from the environment can then take place through slots and / or joints in the process chamber 10 or between the process chamber 10 and the process chamber door 11. However, the provision of the air inlet 5b has the advantage that the flow direction of the air flow F can be set more precisely, so that a substantially laminar,

210185PC horizontal flow over the operating point of the machine 1 can be generated. In alternative embodiments, more than one air inlet 5b and / or more than one air outlet 5a may be provided. The air flow F can also be generated in any other flow direction, for example vertically, instead of in the horizontal direction.

A perspective view of a five-axis laser machine tool 1 according to the invention for the production of moldings by site-selective solidification of powder material to coherent areas by means of laser radiation according to an embodiment is shown in Fig. 4. The illustrated embodiment substantially corresponds to the machine 1 shown schematically in Fig. 1. In Fig. 4, however, no attached to the adjusting axis 22 laser processing head 23 is shown.

The workpiece table 20 is arranged in a process chamber 10 (process booth) which can be closed by a process chamber door 11 and which surrounds the process space 12. A control device 13 arranged outside the process chamber 10 serves as an interface between operator and machine control. For example, measured values and / or warning messages and / or control applications can be displayed on a display of the control device 13. In the process chamber 12, the air outlet 5a is arranged on the left. The dotted arrow illustrates the airflow F generated by the exhaust system. The air inlet 5b is not visible in FIG. 4 because it is obscured by the process room door 11.

FIG. 2 shows a perspective rear view of the five-axis laser machine tool 1 according to the invention. FIG. 2 illustrates further details, not shown in FIG. 4, of the exhaust system. The machine 1 comprises a material powder container cabinet 7 for storing material powder in one or more material powder containers in the material powder container cabinet 7. The material powder container cabinet 7 has a door (not shown) through which an operator can fill the material powder container, not shown, with material powder. From the material powder container cabinet 7 lines lead the material powder to the powder nozzle 15. For transporting the material powder is a carrier gas, such as argon.

The suction system has a blower 2 for generating an air flow, a first suction device for sucking particles from the process space 12 and a second suction device for sucking particles from the material powder container cabinet 7. The first suction device comprises a first exhaust air duct 3a, via which the air outlet 5a arranged in the process chamber 12 is flow-connected to the blower 2. The second suction device comprises a second exhaust duct 3b, via which an air outlet arranged in the material powder container cabinet 7 (not shown) with the blower

210185PC 2 is fluidly connected. The first exhaust duct 3a and the second exhaust duct 3b are connected via a T-piece with a third exhaust duct 3c, which is fluidly connected to the fan 2. The first suction device and the second suction device respectively have means 4a, 4b for setting a suction power. A detail view in Fig. 3 shows the tee, which connects the first exhaust duct 3a and the second exhaust duct 3b with the third exhaust duct 3c. In Fig. 3, the means for adjusting the suction power as throttle valves 4a and 4b in the first exhaust duct 3a and in the second exhaust duct 3b are shown. The throttle valves 4a, 4b can be controlled via actuators 6a, 6b. In particular, the actuators 6a, 6b are controlled by the machine control. By adjusting an opening degree of the throttle valves, an air flow through the first and / or second suction means can be adjusted. In particular, the air flow through the first and / or second suction device can be adjusted as a function of a process and / or as a function of a state of the process chamber door 11 and / or the door of the material powder container 7. Characterized in that the throttle valves 4a, 4b are controlled by actuators 6a, 6b, the setting of the suction power can be fully automatically controlled by the machine control integrated into a process flow. The fan 2 may include one or more filters to filter the extracted particles from the airflow. For example, the fan may have a category C filter with cleaning. The air-filtered particles can be collected in a separate container and removed for disposal. The filtered air flow can either be forwarded via an external exhaust duct or directed to the environment of the machine 1. In particular, when the filtered air flow is directed to the environment of the machine 1, it must be ensured that the air is largely free of harmful particles. For this purpose, the blower may have one or more particulate filters, in particular HEPA filters, for example of the category H13 and / or H14. Other than shown in Fig. 2, a remote blower 2 can be used to generate the exhaust air flow. For example, the fan 2 may be arranged outside a building in which the machine 1 is installed. Thus, the exhaust air can be discharged directly to the outside, so that lower requirements can be made to the filtration of the exhaust air, as if the exhaust air is discharged into the room air.

An exemplary time sequence of the suction will now be described with reference to FIG. 5. The top line in Fig. 5 indicates whether the process is in the "on" or "off" state, that is, whether a process of laser deposition welding is in progress or not. The second line shows the condition of the door

210185PC to the material powder container cabinet 7, so whether the door is currently open or closed. The third line indicates whether the extraction of process space 11 is at full power, at reduced power, or not at all. The bottom line indicates whether the suction of the material powder container cabinet 11 is at full power, at reduced power, or not at all. The state of the process chamber door 11 is not shown in FIG. At the lower edge of FIG. 5, a time axis is shown at the five times Ti to Ts are drawn, which are explained below.

At the time Ti starts the process of laser deposition welding in the machine 1. The door to the material powder container cabinet 7 and the process room door 11 are closed. With the start of the process at the time Ti in each case the suction of the process chamber 12 and the suction of the material container cabinet 7 is raised. Both the extraction of the process chamber 12 and the suction of the material powder container 7 are operated at a reduced power. The power of the suction of the process chamber 12 is throttled, so that the process is not disturbed by an unwanted suction of the material powder from the powder nozzle 15. The performance of the suction of the material powder container cabinet 7 can be done with a locked door with reduced power, as this only an underpressure must be maintained, which is sufficient to prevent leakage of powder material in the environment of the machine 1.

At time T2, the door to the material powder container cabinet 7 is opened by an operator of the machine 1 to refill material powder. In order to avoid the escape of material powder in the environment as much as possible even when the door is open, the power of the suction from the material powder holder 7 is now increased to maximum performance. After the operator has refilled the material powder holder 7, he closes the door again at time T3. The extraction from the material powder container cabinet 7 can now be continued again with reduced power.

At time T ₄ , the process of laser deposition welding in the machine 1 is ended. At this time T ₄ , the power of the extraction of the process chamber 12 is increased to the maximum value in order to clean the process space 12 as completely as possible of welding fumes and other particles. This can prevent harmful particles from entering the environment when opening the process chamber door 11. The extraction at maximum power takes place during a fixed period ΔΤ until the time T ₄ , in which the suction of the process chamber 12 and the material powder container cabinet 7 is turned off. The fixed period ΔΤ is selected so that at the end of the specified period ΔΤ as possible all harmful particles are sucked out of the process chamber 12. The process chamber door 11 may be locked until the time T5, so that an operator of the machine 1, the process room door 11 only

210185PC can then open, if it is ensured that a large part or as possible all harmful particles are sucked out of the process chamber 12.

The method described above can be controlled, for example, by a machine control of the machine 1, which can preferably be operated via the control device 13. As an alternative to the illustrated sequence, the suction can also be continued after the time Ts. However, in order to reduce noise and to save energy, it is advantageous to throttle the exhaust after the specified period ΔΤ or completely shut off.

The operating principle of the laser deposition welding is illustrated with reference to FIG. 6. In Fig. 6, a powder nozzle 15 is shown in the vicinity of a workpiece W to be machined. A focused laser beam L coming from the laser processing head runs coaxially with the powder nozzle 15 and is focused on an operating point on or just above the workpiece Wf. The Werkst off powder P is passed coaxially to the laser beam L through the powder nozzle 15 to the focal point of the laser beam L on the workpiece W. A protective or carrier gas G such as argon also flows through the powder nozzle 15 and thereby transports the material powder P. The protective gas G also serves to prevent unwanted reactions of the heated material powder P or the workpiece W with atmospheric oxygen. In the welding process, a welding smoke S may arise. This welding smoke should be removed from the working space 12 of the machine 1 by the extraction system described above. For this purpose, the extraction system generates the air flow F illustrated by means of dotted arrows, which preferably leads past the workpiece W as a horizontal, laminar flow and thereby entrains the welding smoke S. The strength of the air flow F must be set so that the air flow F does not interfere with the flow of the material powder P with carrier gas G. If the air flow F is set too high, then material powder P can be sucked off the powder nozzle 15, which would disrupt the process.

A typical value of the maximum suction power from the process room is about 1000 m ³ per hour. During throttled operation, approximately 200 to 600 m ³ per hour are drawn off. In comparison, during the laser welding process, typically a stream of about 3 to 6 liters of carrier gas flows with material powder, for example argon, per minute through the powder nozzle 15. When comparing the two values, it should be noted that the exhaust air flow F has a much larger diameter so that the flow velocity of the powder stream (carrier gas with material powder) is usually at least an order of magnitude greater than the flow velocity of the air flow F.

210185 PC The features disclosed in the foregoing description, the claims and the drawings may be of importance both individually and in any combination for the realization of the invention in its various forms.

LIST OF REFERENCE NUMBERS

1 laser machine tool

2 blowers

3a first exhaust duct

3b second exhaust duct

3c third exhaust duct

3d supply air duct

4a first throttle

4b second throttle

5a air outlet

5b air intake

6a first actuator

6b second actuator

7 Material powder container cabinet

10 process chamber

11 process room door

12 process room

13 control device

15 powder nozzle

20 workpiece table

21 machine frame.

22 parking axles

23 laser processing head

L laser beam

W workpiece

P workpiece powder

G protective gas and / or carrier gas

S welding smoke

210185PC

Claims

claims

1. Machine (1) for machining workpieces and / or for producing shaped bodies by locally solidifying material powder (P) to coherent areas by means of a focused laser beam (L), comprising:

a process chamber (10) closable by a process chamber door (11) and surrounding a process space (12);

a closable by a door material powder container cabinet (7) for storing material powder (P); and

a suction system with

a fan (2) for generating an airflow;

one via a first exhaust duct. (3a) with the blower (2) connected to the first suction device for sucking particles from the process chamber (12) and

a second suction device connected to the blower (2) via a second exhaust air duct (3b) for sucking particles out of the material powder container cabinet (7),

characterized in that

the first suction device has means (4a) for controlling a suction power of the first suction device and / or

the second suction means (4b) for controlling a suction power of the second

Having suction.

2. Machine (1) according to claim 1, wherein the means (4a, 4b) for controlling the suction power of the first suction device and / or the second suction device each have actuators.

3. Machine (1) according to claim 1 or 2, wherein in the process space (12) an air inlet (5b) and with the first exhaust duct (3a) flow-connected air outlet (5a) are arranged, so that an air flow (F) via a focal point of the focused laser beam (L) is generated.

4. Machine (1) according to claim 3, wherein the air inlet (5b) and the air outlet (5a) are arranged so that the air flow (F) is generated in the horizontal direction. 5. Machine (1) according to at least one of the preceding claims, wherein the

Means (4a, 4b) are arranged for controlling the suction power of the first suction device and / or the second suction device, the suction power of the first suction device and / or the second suction device in dependence on an opening state of the process chamber door

210185PC (11) and / or to set an opening state of the door of the material powder container cabinet (7).

6. Machine (1) according to at least one of the preceding claims, wherein the means (4a, 4b) are arranged to control the suction of the first suction and / or the second suction, the suction power of the first suction and / or the second suction in dependence from a machining and / or manufacturing process of the machine (1). 7. Machine (1) according to at least one of the preceding claims, wherein the

Means (4a, 4b) are arranged for controlling the suction power of the first suction device and / or the second suction device, the suction power of the first suction device and / or the second suction device depending on the material and / or a material composition of the material powder used (P) adjust.

8. Method for extracting particles from a process chamber (12) in a process chamber (10) of a machine (1) which can be closed by a process chamber door (11) for machining workpieces and / or for producing shaped articles by locally solidifying material powder (P) to contiguous areas by means of a focused laser beam (L), the method comprising the following steps:

Locking the process room door (12) before the machine (1) starts a machining process;

Operating a first suction device for extracting particles from the process space (12) at a reduced power while the machine (1) is performing the machining process;

Operating the first suction for sucking particles from the process space

(12) at maximum power during a specified period (ΔΤ) after a machining process is interrupted or terminated;

Unlocking the process room door (12) after the expiry of the specified period (ΔΤ).

9. The method according to claim 8, with the additional steps:

Operating a second suction device for extracting particles from a material powder container cabinet (7), wherein the suction power of the second suction device is adjusted depending on whether a door of the material powder container cabinet (7) is opened or closed.

210185 PC