Selective laser melting pool radiation detection device

Abstract

The utility model relates to a molten pool radiation detection device applied to selective laser melting equipment. The molten pool radiation detection device comprises a semi-transparent and semi-reflecting mirror, a narrow-band optical filter, a photoelectric detection circuit board, a digital signal processing circuit board and a power management circuit board. The semi-transparent and semi-reflective mirror module comprises a light inlet and two light outlets and comprises a special coated lens, and the lens can transmit working laser with a specific wavelength and simultaneously reflects incident light with other wavelengths in a specular manner. A narrow-band optical filter is arranged at a light outlet in the side face of the photoelectric detection module and used for filtering radiation information of unwanted wavelengths, radiation of specific wavelengths passing through the narrow-band optical filter subsequently reaches the photoelectric detection module and is converted into analog electric signals, then reaches the data processing module and is converted into digital information, and finally the digital information is sent out through the network transmission port. And a power management circuit board is designed for the power supplies of the analog circuit and the digital circuit to realize analog-digital isolation.

Description

TECHNICAL FIELD

[0001] The utility model relates to additive manufacturing detection field especially, it relates to a laser selective melting molten pool radiation detection device. BACKGROUND

[0002] Selective Laser Melting (SLM) is a laser metal additive manufacturing technology with great application prospect. The technology uses high-energy laser to heat and melt metal powder layer by layer according to path planning to realize high-precision metal 3D printing. The characteristics of this production method are that local energy is highly concentrated and laser scanning speed is extremely fast. The main problem currently faced by this technology is that it is difficult to perform effective real-time monitoring due to unstable local energy input and fast scanning speed, especially the monitoring of the smallest forming unit molten pool of laser selective melting. Most of the existing laser selective melting process detection devices need to be additionally modified to the production equipment, and the quality of the collected data is not high. UTILITY MODEL CONTENT

[0003] Therefore, the laser selective melting molten pool radiation detection device provided by the utility model can be directly connected to the light path structure of the production equipment without additional modification to the laser selective melting production equipment, and the molten pool radiation information collected is real-time.

[0004] The utility model provides the following technical scheme: in the first aspect, provide laser selective melting molten pool radiation detection device, the detection device includes assembly shell one and assembly shell two, wherein assembly shell one is provided with laser light inlet, vertical light outlet and side light outlet, the inside of assembly shell one is provided with special coating lens;

[0005] One side of assembly shell two is provided with light inlet, and the other side is provided with network interface, the inside of light inlet is provided with narrowband filter;The inside of assembly shell two is provided with power management circuit board, photoelectric detection circuit board and digital signal processing circuit board.

[0006] Provide a kind of half-mirror device module, including assembly shell and being set on and inside thereof:

[0007] Laser light inlet is general lens interface, is connected with the light outlet of galvanometer system on laser selective melting equipment;

[0008] Special coating lens, the laser of specific wavelength emitted by laser can directly penetrate the lens, and the light of remaining wavelength is specularly reflected on the lens surface;

[0009] Vertical light outlet is general lens interface, is connected with the field lens module on selective laser melting equipment;

[0010] Side light outlet, for general lens interface, connected with photoelectric detection module, the light emitted from the light outlet is the light of non-working laser wavelength reflected by the mirror of the coated lens.

[0011] Preferably, the special coated lens can transmit high-energy laser beams and has strong high-temperature resistance. The lens is installed at an angle of 45° in the assembly shell, and the transmitted light can normally pass through, and the reflected light can be emitted from the side light outlet after mirror reflection.

[0012] In a second aspect, a photoelectric signal acquisition and data processing transmission module is provided, comprising an assembly shell and the following components arranged on and in the shell:

[0013] Light inlet, for general lens interface, connected with the side light outlet of the half-transmission half-reflection mirror module;

[0014] Narrowband optical filter, installed directly behind the lens interface, capable of filtering out unwanted noise and selecting the required wavelength of radiant light intensity information;

[0015] Power management circuit board, converting 220 V AC power into DC working voltage;

[0016] Photoelectric detection circuit board, mainly including photodiode and its supporting circuit, signal amplification circuit, and signal conditioning circuit, etc., converting the characteristic wavelength of radiation filtered out by the narrowband optical filter into an analog electrical signal;

[0017] Digital signal processing circuit board, mainly including embedded microprocessor and its minimum system board circuit, converting the analog output of the photoelectric detection circuit board into a digital signal and performing digital filtering, etc.

[0018] Network interface, connected with the host computer through a network cable to realize stable transmission of the molten pool radiation data.

[0019] Preferably, the narrowband optical filter is selected according to the metal powder printing material used for selective laser melting, and the filter corresponding to the characteristic spectral wavelength with the maximum radiation intensity is selected.

[0020] Preferably, the power management circuit board supplies power to the analog circuit board and the digital circuit board respectively to ensure the electrical isolation of the analog and digital circuit boards.

[0021] Preferably, the photoelectric detection circuit board amplifies weak radiation signals at high speed and high precision.

[0022] Preferably, the digital signal processing circuit board can realize high-speed analog-to-digital conversion.

[0023] The laser selective melting pool radiation detection device, the three light transmission openings of the half-transmission half-reflection mirror module are all general lens interfaces, and are matched with the light path equipment interface of the laser selective melting equipment, so that the device can be directly installed on the laser selective melting production equipment without additional modification, and the 45-degree installed special coated lens in the module can allow the high-energy working laser to pass directly, without affecting the normal work of the laser selective melting equipment.

[0024] The laser selective melting pool radiation detection device, the photoelectric signal acquisition and data processing transmission module first filters and selects the molten pool radiation information reflected on the surface of the aforementioned half-transmission half-reflection mirror module by using a narrow-band filter, the wavelength of the narrow-band filter is determined according to the characteristics of the printing material; the molten pool radiation signal after the filter is converted into an analog signal by a photoelectric detection circuit board and signal amplification and signal conditioning are performed, then the analog signal is converted by a digital signal processing circuit board, and at the same time, a power management circuit board is used to isolate the power supply of the analog circuit; finally, the processed digital signal is transmitted to the upper computer through the network transmission interface. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical scheme of the present application, the drawings needed in the embodiments will be briefly described below.

[0026] Figure 1 The detection device structure schematic diagram provided by the embodiment of the present application is shown in the figure.

[0027] Figure 2 The optical path structure schematic diagram provided by the embodiment of the present application is shown in the figure.

[0028] Figure 3 The data transmission schematic diagram provided by the embodiment of the present application is shown in the figure.

[0029] Explanation of reference signs:

[0030] 1-assembly shell one, 11-laser light inlet, 12-special coated lens, 13-vertical light outlet, 14-side light outlet, 2-assembly shell two, 21-light inlet, 22-narrow-band filter, 23-power management circuit board, 24-photoelectric detection circuit board, 25-digital signal processing circuit board, 26-network interface. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail below with reference to the drawings.

[0032] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention.

[0033] Example: Figure 1 , Figure 2 and Figure 3 These are schematic diagrams of the detection device structure, optical path structure, and data transmission of the present invention, respectively, in conjunction with the following: Figure 1 , Figure 2 , Figure 3 A detailed description of the laser selective melting pool radiation detection device is provided.

[0034] See Figure 1 As shown, the laser selective melting pool radiation detection device described in this embodiment includes a semi-transparent and semi-reflective mirror module assembly shell 1 (hereinafter referred to as assembly shell 1) and a laser light inlet 11, a special coated lens 12, a vertical light outlet 13 and a side light outlet 14 disposed on and inside the shell.

[0035] In this embodiment, the laser light inlet 11, the vertical light outlet 13, and the side light outlet 14 are typically C-Mount standard lens interfaces. In other embodiments, the interface models can be customized and changed according to requirements.

[0036] This specially coated lens 12 can transmit light of a specific wavelength and reflect light of a non-specific wavelength. In this embodiment, the specific wavelength of the transmitted light beam is typically 1064 nm. In other embodiments, this wavelength is adjusted depending on the laser parameters. Besides its semi-transparent and semi-reflective properties, the specially coated lens 12 also exhibits high-temperature resistance. Because the energy of the working laser directly passing through the lens is relatively strong, the lens can typically withstand the long-term penetration of a 400 W laser beam. In other embodiments, this power level is determined by the power parameters of the working laser.

[0037] See Figure 1 As shown, the laser selective melting bath radiation detection device described in this embodiment includes a photoelectric signal acquisition and data processing transmission module assembly housing 2 (hereinafter referred to as assembly housing 2), and an inlet 21, a narrowband filter 22, a power management circuit board 23, a photoelectric detection circuit board 24, a digital signal processing circuit board 25, and a network interface 26 disposed on and inside the housing. In this embodiment, the inlet 21 is a C-Mount standard lens interface; in other embodiments, the interface type can be customized and replaced according to requirements.

[0038] The narrow-band filter 22 is installed at the rear of the lens interface, which can filter out useless noise and screen the radiation intensity information of the required wavelength, and can select the filter with the maximum characteristic spectral wavelength of radiation intensity according to the metal powder printing material selected by laser selective melting. In this embodiment, the characteristic radiation wavelength is selected as 590 nm after experimental comparison of TA1 metal powder, so the narrow-band filter selects 590 nm as the center wavelength, and the filter bandwidth is usually 5 nm. In other embodiments, the center wavelength of the narrow-band filter is changed according to different printing materials, and the bandwidth of the narrow-band filter can also be adjusted according to the detection requirements.

[0039] The power management circuit board 23 supplies power to the analog circuit and digital circuit in this embodiment, mainly converts 220 V AC into ±5 V and ±10 V DC, and supplies power to the analog circuit and digital circuit.

[0040] The photoelectric detection circuit board 24 can convert the molten pool radiation signal into an electrical signal through a PIN photodiode, and other types of photoelectric sensors can also be used in other embodiments. At the same time, an amplification circuit and a filter circuit are designed for the electrical signal. In this embodiment, the voltage value of the electrical signal can be amplified from the mV level to the V level, and the filter circuit in this embodiment selects a Butterworth second-order low-pass active filter circuit.

[0041] The digital signal processing circuit board 25 is a minimum system board with a single-chip microcomputer as the core. In this embodiment, an STM32F767IGT6 single-chip microcomputer produced by STMicroelectronics is selected as the main control chip, and the analog signal is converted by a 12-bit ADC. In other embodiments, the single-chip microcomputer model can be changed according to the needs.

[0042] The network interface 26 is a standard network interface, which connects the digital signal processing circuit board with the host computer through a network cable. In this embodiment, the molten pool radiation data converted by the analog-to-digital converter is transmitted through the UDP transmission protocol, and in other embodiments, the data transmission protocol can be changed according to actual needs.

[0043] Referring to Figure 2As shown in the figure, the black lens part is the core optical device of the laser selective melting pool radiation detection device, namely the coated lens 12 and the narrowband filter 22. In the embodiment, the addition of the laser selective melting pool radiation detection device does not change the original optical path structure of the laser selective equipment, so the influence on the production equipment is small. As shown in the figure, the laser emits high-energy fixed-wavelength laser, which passes through the half-transmission half-reflection mirror module and acts on the forming substrate to form a molten pool. The radiation and reflected laser of the molten pool return along the original optical path. When reaching the half-transmission half-reflection mirror, the reflected laser directly penetrates, the molten pool radiation is mirror reflected, and the molten pool radiation reaches the detection circuit after passing through the narrowband filter.

[0044] Referring to Figure 3 As shown in the figure, the data transmission schematic diagram of the laser selective melting pool radiation detection device is shown. The molten pool radiation signal reaches the photoelectric detection circuit, is amplified and filtered to form an analog signal, and then is transmitted to a digital signal processing circuit board. The data is sequentially subjected to AD conversion, digital filtering, data packaging, data caching and data transmission on the digital signal processing circuit board. Finally, the detection data in the embodiment is transmitted to the industrial computer.

[0045] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A laser selective melting molten pool radiation detection device, characterized in that, The detection device includes a first assembly housing (1) and a second assembly housing (2), wherein the first assembly housing (1) is provided with a laser light inlet (11), a vertical light outlet (13) and a side light outlet (14), and a special coated lens (12) is provided inside the first assembly housing (1). The second assembly housing (2) has a light inlet (21) on one side and a network interface (26) on the other side. A narrow-band filter (22) is installed inside the light inlet (21). The second assembly housing (2) has a power management circuit board (23), a photoelectric detection circuit board (24) and a digital signal processing circuit board (25) installed inside.

2. The laser selective melting pool radiation detection device according to claim 1, characterized in that, The laser inlet (11) is connected to the output port of the galvanometer system on the laser selective melting equipment; Special coated lens (12) allows laser light of a specific wavelength emitted by the laser to pass directly through the lens, while light of other wavelengths undergoes specular reflection on the lens surface; The vertical light outlet (13) is connected to the field lens module on the selective laser melting device; The side light outlet (14) is connected to the photoelectric detection module. The light emitted from this light outlet is light of a non-working laser wavelength that undergoes specular reflection on the coated lens.

3. The laser selective melting pool radiation detection device according to claim 1, characterized in that, The light inlet (21) is connected to the side light outlet of the semi-transparent and semi-reflective mirror module; A narrowband filter (22) is installed directly behind the lens interface to filter out unwanted noise and select the radiation intensity information of the required wavelength; a power management circuit board (23) converts 220V AC power into DC operating voltage. The photoelectric detection circuit board (24) mainly includes a photodiode and its supporting circuit, a signal amplification circuit and a signal conditioning circuit, which converts the radiation of the characteristic wavelength filtered out by the narrow band filter into an analog electrical signal; The digital signal processing circuit board (25), including an embedded microprocessor and its minimum system board circuit, converts the analog output of the photoelectric detection circuit board into a digital signal and performs digital filtering; The network interface (26) is connected to the host computer via a network cable to achieve stable transmission of molten pool radiation data.

4. The laser selective melting pool radiation detection device according to claim 1, characterized in that, The special coated lens (12) is installed at a 45° angle inside the assembly housing. The transmitted light passes through normally, and the reflected light is emitted from the side light outlet (14) after being reflected by the mirror.

5. The laser selective melting pool radiation detection device according to claim 1, characterized in that, Narrowband filter (22), a special coated structure filter lens customized according to the laser selective melting process.

Images