DEVICE FOR THE ADDITIVE PRODUCTION OF THREE-DIMENSIONAL COMPONENTS

Abstract

Device for the additive production of three-dimensional components (2), namely a laser melting device or laser sintering device, in which a component (2) is produced by successive solidifying of individual layers (3) made from solidifiable construction material, by the effect of radiation (4), through melting of the construction material (5), wherein the dimensions and/or temperature of the melt area (6) generated by a point-shaped or line-shaped energy input can be captured by a sensor device (8) of a process monitoring system, and sensor values for evaluation of a component quality can be deduced therefrom, wherein the radiation (9) created by the melt area and used for the generation of the sensor values passes through the scanner used for the melt energy input, and is guided from there to the sensor device (8) of the process monitoring system, wherein an optical focus tracking device (20) is arranged in the radiation path used for generation of the sensor values between the scanner (10) and the sensor device (8) of the process monitoring system, which optical focus tracking device can be controlled by electronic machine data for focus tracking.

Claims

1. A device for the additive production of three-dimensional components (2), namely a laser melting device or a laser sintering device, in which a component (2) is produced by successive solidification of individual layers (3) of construction material that can be solidified as a result of the impact of radiation (4) by melting on the construction material (5), wherein the melting section (6) created by a point-type or linear energy input can be detected using a sensor device (8) of a process monitoring system regarding its dimension shape and/or regarding its temperature, and sensor values for evaluating a component quality can be derived therefrom, wherein the radiation (9) created by the melting section and used for the generation of the sensor values penetrates the scanner employed for the melting energy input, and is directed to the sensor device (8) of the process monitoring system by said scanner, characterized in that in the optical path used for the generation of the sensor values between the scanner (10) and the sensor device (8) of the process monitoring system an optical focus tracking device (20) is arranged that can be actuated by electronic machine data to track focus.

2. The device according to claim 1, characterized in that the optical path of the device at least comprising the radiation source and the scanner is provided with an optical adjustment device (30) to adjust the melting beam focus.

3. The device according to claim 1, characterized in that a focus adjustment of the melting beam (4) is carried out by mechanically moving the construction plane (7).

4. The device according to claim 1, characterized in that the machine data are or comprise the scanner actuation data of the PC scanner actuation card.

5. The device according to claim 1, characterized in that the machine data are or comprise data derived from construction process parameters.

6. The device according to claim 1, characterized in that the focus tracking optics has at least one optical focusing element that can be moved by a motor.

7. The device according to claim 1, characterized in that the focusing element is formed as a lens set that can be moved by a motor.

8. The device according to claim 1, characterized in that the focus adjustment of the process monitoring system can be performed by the focus tracking optics prior to the focus adjustment of the melting beam directed to the layer of powder.

9. The device according to claim 1, characterized in that the sensor device (8) comprises a plurality of photosensitive elements (15, 16) that can selectively or collectively be brought into the beam of the process monitoring system.

10. The device according to claim 1, characterized in that a sensor of the process monitoring system is designed for a wavelength range of 780-950 nm.

11. The device according to claim 1, characterized in that a sensor is designed for a wavelength range of around 1,200 nm.

12. The device according to claim 1, characterized in that the electronic signals derived from several sensors are processed in parallel in a process monitoring system.

13. The device according to claim 1, characterized in that the focus tracking of the focus tracking device is formed for the compensation of the melting beam exiting the melting beam focus adjustment of the scanner.

Description

[0016] The device 1 shown in FIG. 1 of the drawings is for the additive production of three-dimensional components 2 produced by successive solidification of individual layers 3 of construction material that can be solidified as the result of the impact of a radiation 4 by melting on the construction material 5. The melting section 6 in the construction plane 7 created by a point-type or linear energy input is detected using a sensor device 8 of a process monitoring system regarding its dimension shape and/or regarding its temperature. Therefrom sensor values for evaluating a component quality are derived, wherein the radiation 9 created by the melting section 6 and used for the generation of the sensor values penetrates the scanner 10 employed for the melting energy input in reverse direction, and is directed to the sensor device 8 of the process monitoring system by said scanner. Process monitoring systems, in which the reflected radiation created by the melting section is directed to a sensor device by the scanner in reverse direction, are referred to as so-called coaxial process monitoring systems, because the radiation emanating the laser for energy input and the reflected radiation for the process monitoring system penetrate the scanner coaxially.

[0017] The sensor device 8 can comprise a camera 15, a photodiode 16 or also several photosensitive elements, wherein it can be provided that the radiation 9 used for the generation of sensor values penetrates a beam splitter 17, which distributes the radiation e.g. to the camera, the photodiode or further photosensitive elements.

[0018] According to the invention, an optical focus tracking device 20 is arranged between the scanner 10 and the sensor device 8 of the process monitoring system, which can be readjusted by electronic machine data 21, 22 to track focus.

[0019] The focus tracking device comprises at least one optical focusing element that can be adjusted by a motor, e.g. a lens set 23 that can be moved by a motor, which serves the purpose of performing a refocusing of the radiation 9 used for the generation of the sensor values.

[0020] Refocusing is performed, when either the optical path of the device comprising at least the radiation source and the scanner is provided with an optical adjustment device 3 for melting beam focus adjustment, or a focus adjustment of the melting beam is carried out by mechanically moving the construction plane 7.

[0021] The machine data can on the one hand be or comprise scanner actuation data from a scanner actuation card, wherein such scanner actuation data primarily affect a 3D scanner regarding the z-axis focusing.

[0022] The machine data can, however, also be or comprise data derived from construction process parameters, especially data used for height adjustment of the construction plane, because a height adjustment of the construction plane also results in defocusing the melting beam.

[0023] The machine data delivered to the focus tracking device 20 can be controlled regarding time such that a focus tracking of the radiation 9 used for the generation of the sensor values using the focus tracking device 20 results into a z-axis adjustment of a 3D scanner 10 or a height adjustment of the construction plane. This ensures that upon application of the laser radiation and thus generation of the melting pool, which is to be monitored, the beam 9 used for the generation of the sensor values is already optimized regarding its focus.

[0024] In order to be able to evaluate the data from the sensor device 8, i.e. the camera data from the camera 15 and the sensor data from the photodiode 16, a processor unit is provided, in which the data can be processed, stored and be brought into a format that enables visualization of the 3D data for example for reverse engineering.

LIST OF REFERENCE NUMBERS

[0025] 1. Device

[0026] 2Component

[0027] 3 Layer

[0028] 4 Radiation

[0029] 5 Construction material

[0030] 6 Melting section

[0031] 7 Construction plane

[0032] 8 Sensor device

[0033] 9 Radiation

[0034] 10 Scanner

[0035] 15 Camera

[0036] 16 Photodiode

[0037] 17 Beam splitter

[0038] 20 Focus tracking device

[0039] 21 Machine data

[0040] 22 Machine data

[0041] 23 Lens set