JP7330402B1 - Additive manufacturing equipment - Google Patents

Abstract

The additive manufacturing apparatus includes a first material supply section, a processing beam source, a processing head, a two-color temperature camera, and a control section. The first material supply unit supplies a first supply material having a chemical composition different from that of the workpiece toward the processing area. A processing beam source outputs a processing beam that heats the first feed material and the workpiece. The processing head irradiates the processing beam to the processing area. A two-color temperature camera images an imaging region including a processing region with light of at least two wavelength bands. The control unit calculates temperature distribution information including the temperature of the workpiece, the first supply material, and the molten pool where the workpiece and the first supply material are melted in the machining area, based on the measurement results obtained by the two-color temperature camera. do. Further, the control unit selects from the output of the processing beam of the processing beam source, the scan speed which is the speed at which the processing beam is scanned, and the material supply speed which is the supply speed of the first supply material, based on the temperature distribution information. Control processing parameters including at least one.

Description

The present disclosure relates to an additive manufacturing apparatus that manufactures three-dimensional structures.

2. Description of the Related Art In an additive manufacturing apparatus that manufactures a three-dimensional model, a technique is known for estimating the quality of the three-dimensional model in real time during modeling. Patent Document 1 describes a material injection unit that injects a material for a three-dimensional object onto a modeling table on which the three-dimensional object is formed, and a light irradiation unit that irradiates the injected material with a light beam that is an example of a processing beam. a data acquisition unit that acquires monitoring data for monitoring the modeling state of the three-dimensional model during the modeling of the three-dimensional model; and an estimation of the modeling quality of the three-dimensional model based on the monitoring data. A build quality estimator is disclosed.

JP 2018-34514 A

By the way, in the calculation of the temperature of the workpiece in the additive manufacturing equipment, generally different emissivity is used depending on the composition of the workpiece. In the manufacture of a three-dimensional modeled object with an additive manufacturing apparatus, when the composition of the three-dimensional modeled object in the processing region, which is the region where the processing beam is irradiated onto the workpiece, contains a plurality of materials, one example is the supply material and the workpiece. There is a case where the composition differs from the workpiece. In such a case, there is a problem that it is difficult to perform accurate temperature measurement using emissivity. If it is not possible to accurately measure the temperature of the processing area, it is not possible to precisely control processing parameters including the scanning speed of the processing beam and the supply speed of the material to be supplied. As a result, there is a problem that the deviation between the shape of the three-dimensional model formed by the additive manufacturing and the target shape becomes large.

The present disclosure has been made in view of the above. It is an object of the present invention to obtain an additive manufacturing apparatus that can be realized with high precision by

In order to solve the above-described problems and achieve the object, the additive manufacturing apparatus according to the present disclosure includes a first material supply section, a processing beam source, a processing head, a two-color temperature camera, and a control section. Prepare. The first material supply unit supplies a first supply material having a chemical composition different from that of the workpiece toward the machining area of the workpiece. A processing beam source outputs a processing beam that heats the first feed material and the workpiece. The processing head irradiates a processing area with a processing beam from a processing beam source. A two-color temperature camera images an imaging region including a processing region with light of at least two wavelength bands. Based on the result of measurement by the two-color temperature camera, the control unit determines the temperature distribution of the imaging region including the temperatures of the workpiece , the first supply material, and the molten pool in which the workpiece and the first supply material are melted in the processing area. Temperature distribution information indicating is calculated. Further, the control unit selects from the output of the processing beam of the processing beam source, the scan speed which is the speed at which the processing beam is scanned, and the material supply speed which is the supply speed of the first supply material, based on the temperature distribution information. Control processing parameters including at least one.

The additive manufacturing apparatus according to the present disclosure realizes additive manufacturing between dissimilar materials with higher accuracy than before even when a supply material having a chemical composition different from that of the workpiece is added to the workpiece. It has the effect of being able to

A diagram schematically showing an example of the configuration of an additional manufacturing apparatus according to Embodiment 1. FIG. 4 is a diagram showing an example of a contour map of temperature distribution in an imaging area of a two-color temperature camera; A diagram schematically showing an example of the emissivity distribution in the imaging range of a two-color temperature camera. Flowchart showing an example of the procedure of the control method for the additive manufacturing apparatus according to the first embodiment A diagram schematically showing an example of a configuration of an additional manufacturing apparatus according to a second embodiment. A diagram schematically showing an example of a contour plot of the preheated feed material and the temperature distribution near the processing area. A diagram schematically showing an example of a condensed spot divided by a diffraction grating A diagram showing an example of a configuration of an additive manufacturing apparatus according to a third embodiment. FIG. 4 is a diagram showing an example of a hardware configuration of a control unit of the additive manufacturing apparatus according to Embodiments 1 to 3;

An additional manufacturing apparatus according to an embodiment of the present disclosure will be described in detail below with reference to the drawings.

Embodiment 1.
FIG. 1 is a diagram schematically showing an example of the configuration of an additional manufacturing apparatus according to Embodiment 1. FIG. The additive manufacturing apparatus 1 is an apparatus for forming a target shape by melting a supply material 111 with a processing beam B and adding it onto a workpiece 31 . The additional manufacturing apparatus 1 includes a material supply unit 11 that supplies a supply material 111 onto a workpiece 31, a machining beam source 12 that emits a machining beam B, and irradiates the supply material 111 and the workpiece 31 with the machining beam B. and a processing head 13 for processing.

The material supply unit 11 supplies the supply material 111 to the processing area. The material supply unit 11 can change the material supply speed, which is the speed at which the supply material 111 is supplied onto the workpiece 31, according to instructions from the control unit 17, which will be described later. The supply material 111 is supplied toward the processing area, but the supply angle and direction are not particularly limited. In the example of FIG. 1, the supply material 111 is supplied to the workpiece 31 from obliquely above the workpiece 31, and the processing beam B is made to enter the workpiece 31 perpendicularly. may be supplied perpendicularly to the workpiece 31 and the machining beam B may be incident obliquely. In Embodiment 1, the supply material 111 is assumed to be a metal wire, which is a wire-shaped metal. Also, the metal wire has a different chemical composition than the workpiece 31 . In one example, feedstock 111 corresponds to the first feedstock. Note that the additive manufacturing apparatus 1 of Embodiment 1 performs additive manufacturing using different materials, and has a plurality of material supply units 11 that supply supply materials having different chemical compositions (not shown). That is, in FIG. 1, the workpiece 31 is shaped by supplying a supply material having a chemical composition different from that of the supply material 111 shown in the figure from a material supply unit (not shown).

The processing beam source 12 emits a processing beam B. As shown in FIG. When the processing beam B is laser light, the processing beam source 12 is a laser oscillator that emits laser light such as a solid-state laser, gas laser, or semiconductor laser. When the processing beam B is an electron beam, the processing beam source 12 is an electron gun.

The processing head 13 irradiates the processing beam B emitted from the processing beam source 12 onto the workpiece 31 . When the machining beam B is laser light, the machining beam source 12 and the machining head 13 are connected by an optical fiber 14 . In this case, laser light is transmitted by the optical fiber 14 . The processing head 13 also has a drive mechanism (not shown). The drive mechanism drives the machining head 13 horizontally with respect to the workpiece 31 . Thereby, the processing head 13 can scan the processing beam B over the workpiece 31 . The drive mechanism can change the scan speed, which is the speed at which the processing beam B is caused to scan over the workpiece 31 , according to instructions from the control unit 17 . Note that the drive mechanism may drive the processing head 13 in the vertical direction with respect to the workpiece 31 .

In the processing region, which is the region irradiated with the processing beam B on the workpiece 31, the supply material 111, the workpiece 31, or both the supply material 111 and the workpiece 31 are heated and melted. A pond 32 is formed. The hot molten pool 32 that forms cools on the work piece 31 , drops below its melting point, and solidifies to add metal onto the work piece 31 . By continuously supplying the supply material 111 while moving the processing head 13, a bead, which is a linear additional layer, is formed. can be done.

The additive manufacturing apparatus 1 includes a two-color temperature camera 15 that captures images of a predetermined area including a machining area, which is an area irradiated with the machining beam B on the workpiece 31, with light of at least two wavelength bands.

A two-color temperature camera 15 measures the temperature distribution of the processing area and its surrounding area. Below, the area in which the two-color temperature camera 15 measures the temperature distribution is referred to as the imaging area. The two-color temperature camera 15 is a radiation thermometer that acquires a two-dimensional temperature distribution, and obtains the surface temperature of an object included in its field of view by measuring thermal radiance from the object. The two-color temperature camera 15 is installed outside the processing head 13 in one example, as shown in FIG. However, this is only an example, and it may be built in the processing head 13 by sharing a part of the optical system with the processing beam B or the like.

The two-color temperature camera 15 in Embodiment 1 is installed so as to include the molten pool 32, the feed material 111, and the workpiece 31 around the molten pool 32, that is, the processing area. The use of a two-color temperature camera 15 allows real-time simultaneous measurement of the temperature distribution of the feedstock 111, the workpiece 31 and the weld pool 32 of different chemical compositions during processing.

The additional manufacturing apparatus 1 uses a display 16 for displaying information indicating the state of the processing area to the operator, and the measurement results obtained by the two-color temperature camera 15 to set parameters for operating the additional manufacturing apparatus 1 during processing. and a control unit 17 that controls certain machining parameters and displays information indicating the state of the machining area on the display 16 .

The display 16 displays temperature distribution information, which is information indicating the temperature distribution of the imaging region including the processing region calculated by the control unit 17 . An example of the display 16 is a liquid crystal display panel. The display 16 corresponds to the display section.

The control unit 17 calculates the temperature distribution of the imaging region including the processing region from the measurement results of the two-color temperature camera 15, and controls the processing parameters based on the calculated temperature distribution. The control unit 17 calculates the radiance ratio from the light intensity of each pixel in the image of the imaging region in the two close wavelength bands of the two-color temperature camera 15, and calculates the temperature at each pixel from the radiance ratio. As a result, a temperature distribution is obtained by determining the temperature of each pixel of the image of the imaging area. The control unit 17 displays temperature distribution information, which is information indicating the temperature distribution in the imaging region, on the display 16 .

In one example, the control unit 17 displays the temperature distribution of the imaging area using a contour map on the display 16 as the temperature distribution information. Thereby, the temperature of the imaging region measured by the two-color temperature camera 15 is visually displayed. FIG. 2 is a diagram showing an example of a contour map of temperature distribution in an imaging region of a two-color temperature camera. As shown in FIG. 2, the results of simultaneously measuring the temperature of the molten pool 32, the solid-state workpiece 31 around it, and the temperature of the feed material 111 immediately before being conveyed to the molten pool 32 are displayed on the display 16. be done. In the contour plot shown in FIG. 2, in addition to the temperature of the workpiece 31 having the highest temperature near the center of the working area, i.e., the molten pool 32 and decreasing in temperature away from the working area, The operator can visually recognize the temperature, the temperature of the molten pool 32, the temperature distribution in the imaging area, and the maximum temperature in the imaging area in a short time.

The control unit 17 acquires the measured temperature of the molten pool 32 using the temperature distribution information calculated from the results measured by the two-color temperature camera 15, and adjusts the measured temperature of the molten pool 32 so that it approaches a preset target value. Second, the output of the working beam B of the working beam source 12, in this case the laser output, is controlled. Specifically, the control unit 17 sets the upper and lower limit values T _H and T _L of the set temperature range as the target temperature values. The controller 17 reduces the laser output when the measured temperature T of the molten pool 32 measured by the two-color temperature camera 15 is higher than the upper limit value T _H , that is, when T>T _H . The controller 17 increases the laser output when the measured temperature T of the molten pool 32 is lower than the lower limit value T _L , that is, when T<T _L . By performing such control, the amount of energy incident on the molten pool 32 is adjusted.

In addition, when T<T _L , the control unit 17 slows down the scan speed, which is the speed at which the processing beam B is scanned, to increase the amount of heat input per unit area of the workpiece 31. At the same time, the supply material The material supply speed, which is the supply speed of 111, is slowed down and controlled so that the volume of modeling per unit area of the workpiece 31 is kept constant. When T>T _H , the control unit 17 increases the scanning speed of the processing beam B to reduce the amount of heat input per unit area of the workpiece 31, and at the same time increases the material supply speed of the supply material 111. Alternatively, the molding volume per unit area of the workpiece 31 may be kept constant. In the first embodiment, the scanning speed of the processing beam B is also the speed at which the processing head 13 is scanned.

Thus, the control unit 17 controls processing parameters including at least one selected from the output of the processing beam B of the processing beam source 12 , the scan speed of the processing beam B, and the material supply speed of the supply material 111 .

In addition, the control unit 17 calculates the emissivity at each position in the imaging range captured by the two-color temperature camera 15 using the temperature measured by the two-color temperature camera 15, and obtains information indicating the distribution of the emissivity in the imaging range. is displayed on the display unit. Emissivity is measured for each pixel of the two-color temperature camera 15 . Here, the calculation of the temperature distribution and the emissivity distribution using the measurement results of the two-color temperature camera 15 will be described. An ideal object whose absorptivity is 1 for light of all wavelengths is called a black body, and the spectral radiance _Ibb due to thermal radiation from the black body is expressed by the following equation (1) according to Planck's law. In equation (1), T is the absolute temperature, λ is the wavelength of light, and A and B are known constants consisting of scientific constants.

I _bb (λ, T)=A/{λ ⁵ (exp(B/λT)−1)} (1)

The radiance of thermal radiation emitted by an object that is not a black body is weaker than that of a black body, and the coefficient representing the ratio is called the emissivity. It is generally known as Kirchhoff's law that emissivity coincides with absorptivity. The spectral radiance I from an actual object is expressed by the following equation (2) where ε(λ) is the emissivity.

I(λ,T)=ε(λ)A/{λ ⁵ (exp(B/λT)−1)} (2)

Since the actually measured radiance I _sys of the black body is only in the wavelength band to which the camera has sensitivity, the following equation (3) is obtained if C(λ) is a coefficient specific to the camera.

I _sys (T)=∫C(λ)A/{λ ⁵ (exp(B/λT)−1)}dλ (3)

A technique is known for measuring temperature by approximating the emissivity to be the same if the radiance is measured in two close wavelength bands. An example of this technique is disclosed in Japanese Unexamined Patent Application Publication No. 2004-45306. A two-color temperature camera 15 is a method for performing temperature measurement using this technique. The two-color temperature camera 15 can measure temperature without giving the emissivity. Therefore, it is also possible to calculate the emissivity from the measured temperature. From the radiances I _obs and I _sys measured by the two-color temperature camera 15, the emissivity ε is obtained from the following equation (4).

ε=I _obs /I _sys (4)

Here, since it is assumed that the two-color temperature camera 15 measures only a narrow wavelength range, it is assumed that the emissivity ε does not change with respect to the wavelength in the equation (4). Further, the radiance I _obs is determined based on the temperature calculated for each pixel of the two-color temperature camera 15 from the relationship between the temperature of the member to be measured and the radiance at a predetermined wavelength λ. is the radiance at wavelength. The radiance I _sys is the radiance of a black body at a given wavelength determined based on the temperature calculated for each pixel of the two-color temperature camera 15 from the given relationship between the temperature and radiance of the black body. is. As described above, the control unit 17 displays the emissivity distribution information of the imaging area including the processing area obtained by the two-color temperature camera 15 on the display 16 . As an example, it is desirable that the control unit 17 displays the temperature distribution information and the emissivity distribution information side by side on one screen on the display 16 . This allows the operator to check the emissivity distribution displayed on the display 16. FIG.

Although the emissivity of the work piece 31 and the feed material 111 is uniform, the work piece 31 and the feed material 111 mix, alloy, form compounds or oxides, etc. in the molten pool 32 and its surroundings. The emissivity changes for the following reasons. That is, by generating an emissivity profile, changes in chemical state or composition around the processing area can be visualized during processing.

FIG. 3 is a diagram schematically showing an example of the emissivity distribution in the imaging range of the two-color temperature camera. FIG. 3 shows an example in which the feed material 111 and the workpiece 31 have constant emissivity and different emissivity near the molten pool 32 . That is, a different composition or chemical state is realized near the molten pool 32, which appears as a difference in emissivity. Thus, the emissivity distribution provides a visualization of changes in chemical state or composition in the imaging area. The change in composition can also be referred to as the spatial distribution of composition. By simultaneously displaying the temperature distribution in FIG. 2 and the emissivity distribution in FIG. Then, the operator estimates the processing quality from the visualized chemical state or the spatial distribution of the composition among the information indicating the processing state. In addition, the work of estimating the processing quality from the visualized chemical state or the spatial distribution of the composition depends on the combination of the workpiece 31 and the supply material 111, and the operator is empirically required Based on the information Estimate processing quality.

Here, a method of controlling the additive manufacturing apparatus 1 will be described. FIG. 4 is a flow chart showing an example of the procedure of the control method for the additive manufacturing apparatus according to the first embodiment. First, the control unit 17 of the additional manufacturing apparatus 1 acquires images of two close wavelength bands in the imaging region measured by the two-color temperature camera 15 (step S11). The control unit 17 calculates the radiance ratio in each pixel of the two acquired images, and calculates the temperature of each pixel from the radiance ratio (step S12). Here, the temperature is calculated from the radiance ratio using information in which the relationship between the radiance ratio of the two wavelength bands and the surface temperature of the object to be measured is calculated in advance. The control unit 17 generates temperature distribution information indicating the temperature distribution of each pixel in the imaging region (step S13). The controller 17 displays the temperature distribution information on the display 16 (step S14).

Further, the control unit 17 calculates the radiance I _obs at a predetermined wavelength from the temperature of each pixel and the radiance I _sys of a black body at the predetermined wavelength, and calculates the emissivity of each pixel in the imaging region. is calculated (step S15). The control unit 17 generates emissivity distribution information indicating the emissivity distribution of each pixel in the imaging region (step S16). The controller 17 displays the emissivity distribution information on the display 16 (step S17). At this time, if the number of display devices 16 is one, the control unit 17 preferably causes the display device 16 to display the emissivity distribution information together with the temperature distribution information. In this way, the operator can be provided with the temperature distribution in the working area as well as the emissivity distribution corresponding to changes in chemical state or composition in the working area.

The control unit 17 acquires the temperature of the molten pool 32 from the temperature distribution information (step S18), and determines whether the temperature of the molten pool 32 is higher than the upper limit of the set temperature range (step S19). The set temperature range is the temperature range of the molten pool 32 that is desired to be maintained during the build process, as determined by the combination of the workpiece 31 and feed material 111 . In one example, the control unit 17 can acquire the temperature in the molten pool 32 by estimating that the highest region in the temperature distribution information is the molten pool 32 . When the temperature of the molten pool 32 is equal to or lower than the upper limit value of the set temperature range (No in step S19), the controller 17 determines whether the temperature of the molten pool 32 is lower than the lower limit value of the set temperature range. (step S20).

When the temperature of the molten pool 32 is equal to or higher than the lower limit of the set temperature range (No in step S20), the temperature of the molten pool 32 is controlled to be within the set temperature range. Therefore, the process returns to step S11 without performing any special process.

If the temperature of the molten pool 32 is higher than the upper limit of the set temperature range in step S19 (Yes in step S19), or if the temperature of the molten pool 32 is lower than the lower limit of the set temperature range in step S20 (step If Yes in S20), the control unit 17 sets at least one of the processing parameters including the laser output, the scanning speed of the processing beam B, and the material supply speed of the supply material 111 so that the temperature of the molten pool 32 is the set temperature. It is changed so as to be within the range (step S21). In one example, when the temperature of the molten pool 32 is higher than the upper limit of the set temperature range, the controller 17 reduces the laser output. When the temperature of the molten pool 32 is lower than the lower limit of the set temperature range, in one example, the controller 17 increases the laser output, or in another example, slows down the scanning speed of the processing beam B, Slow down the material feed rate of feed material 111 . After that, the process returns to step S11.

In Embodiment 1, the additional manufacturing apparatus 1 includes a material supply unit 11 that supplies a supply material 111 having a chemical composition different from that of the workpiece 31 toward the machining area of the workpiece 31, At least a processing beam source 12 that supplies a processing beam B for heating an object 31 toward a processing area, a processing head 13 that irradiates the processing beam B from the processing beam source 12 to the processing area, and an imaging area including the processing area. and a two-color temperature camera 15 that captures images with light in two wavelength bands. In addition, in the first embodiment, the additional manufacturing apparatus 1 determines whether the workpiece 31 and the supply material 111 in the machining area and the workpiece 31 and the supply material 111 are melted based on the measurement results obtained by the two-color temperature camera 15. Temperature distribution information indicating the temperature distribution of the imaging region including the temperature of the molten pool 32 is calculated, and based on the temperature distribution information, the output of the processing beam B of the processing beam source 12 and the scan speed, which is the speed at which the processing beam B is scanned. , and a control unit 17 that controls processing parameters including at least one selected from the material supply speed of the supply material 111 . As a result, even when the feed material 111 having a chemical composition different from that of the workpiece 31 is added to the workpiece 31, the temperature at each position in the machining region can be calculated without using the emissivity of each material. can be measured more accurately. As a result, the processing parameters including at least one selected from the output of the processing beam source 12, the scanning speed of the processing beam B, and the material supply speed of the supply material 111 can be controlled with high accuracy, compared to the conventional method. As a result, it is possible to realize additive manufacturing between different materials with high accuracy.

Further, the controller 17 displays the temperature distribution information on the display 16 . This enables the operator to grasp the temperature distribution in the processing area. Furthermore, the control unit 17 displays on the display 16 the emissivity distribution information indicating the emissivity of each pixel in the imaging region obtained from the measurement results of the two-color temperature camera 15 . The emissivity distribution provides a visualization of changes in chemical state or composition in the imaging area. This allows the operator to estimate the processing quality from the relationship between the change in chemical state or composition and the processing quality.

Embodiment 2.
FIG. 5 is a diagram schematically showing an example of the configuration of an additional manufacturing apparatus according to Embodiment 2. FIG. FIG. 5 shows the case where the processing beam B is the laser beam L. As shown in FIG. In addition, the same code|symbol is attached|subjected to the component same as FIG. 1, and the description is abbreviate|omitted.

In the additional manufacturing apparatus 1A according to the second embodiment, the processing head 13A is different from that of the first embodiment. Moreover, in the additional manufacturing apparatus 1A according to the second embodiment, the two-color temperature camera 15 is provided at a position within the processing head 13A capable of imaging the processing region.

The processing head 13A includes a transmission optical system 130 for emitting the laser light L from the optical fiber 14 from the output end, and a preheating optical element 132 for branching a part of the laser light LB to preheat the supply material 111. have. The preheating optical element 132 corresponds to the preheating section. In the example of FIG. 5, the processing head 13A includes a collimator lens 131 for collimating the laser light L from the optical fiber 14, a preheating optical element 132 for irradiating part of the laser light L onto the supply material 111, a preheating a reflecting mirror 133 that reflects the laser beams LA and LB that have passed through the optical element 132 for processing; Note that the collimator lens 131, the reflecting mirror 133, and the condenser lens 134 are merely examples, and any configuration can be used as long as the laser beam L from the optical fiber 14 can be focused on the processing position. good too.

Heating the feed material 111 just prior to delivery to the processing region by an energy source different from the processing beam B or a portion of the processing beam B is referred to herein as preheating. In the second embodiment, a preheating optical element 132 as a preheating section is inserted into the transmission optical system 130 that guides the laser beam L, which is the processing beam B, to the processing area. As a result, part of the laser light L can be irradiated onto the supply material 111 before entering the processing area, and the supply material 111 can be preheated. That is, in the transmission optical system 130 in which the preheating optical element 132 is not inserted, the laser beam L is irradiated as the laser beam LA onto the processing area where the molten pool 32 is formed. , a part of the laser beam LB of the laser beam L is irradiated onto the supply material 111 before entering the processing area. That is, the vicinity of the tip of the feed material 111 is preheated. By preheating the feed material 111, the feed material 111 entering the molten pool 32 is rapidly melted in the processing area, thereby enabling stable continuous processing.

FIG. 6 is a diagram schematically showing an example of a contour map of temperature distribution in the vicinity of the preheated feed material and processing area. The temperature of the feed material 111 is higher at the preheating point than in FIG. 2 in which the preheating mechanism is not provided. Typically, the preheating point of the feedstock 111 is near the working area.

The preheating optical element 132 to be inserted is any optical element designed according to the processing application, such as a lens, a lens array, a diffraction grating, a metalens, or a spatial phase modulator. These preheating optical elements 132 slightly modulate the processing beam B to change the shape of the focused spot in the processing area. The preheating optical element 132 in FIG. 5 is a diffraction grating, and by modulating the traveling direction of a part of the laser light L which is the processing beam B, the laser light LA irradiated to the processing area and the supply material 111 and the laser beam LB to be irradiated. As a result, the focused spot in the processing area is split into two.

FIG. 7 is a diagram schematically showing an example of a condensed spot split by a diffraction grating. As shown in FIG. 7, the focused spot SP1 heats the working area and the divergent focused spot SP2 preheats the feed material 111 . In addition, the profile may be adjusted according to preheating conditions and processing conditions, such as increasing the beam diameter of the preheating optical element 132 or forming an elliptical spot.

In the second embodiment, the processing head 13A includes a transmission optical system 130 that emits the laser light L from the optical fiber 14 from the output end, and a preheating optical element that splits a part of the laser light L to preheat the supply material 111. 132. As a result, the laser beam L is split into two laser beams LA and LB, one of the laser beams LA is irradiated to the processing area, and the other laser beam LB is irradiated to the supply material 111 immediately before entering the processing area. , to preheat the feedstock 111 . By preheating the feed material 111, the feed material 111 entering the processing area is rapidly melted, enabling stable continuous processing.

Embodiment 3.
FIG. 8 is a diagram illustrating an example of a configuration of an additional manufacturing apparatus according to Embodiment 3; In addition, the same code|symbol is attached|subjected to the component same as Embodiment 1, and the description is abbreviate|omitted. In Embodiment 3, the additional manufacturing apparatus 1B further includes a material supply unit 18 that supplies a powdery supply material 181 to the processing area. The material supply unit 18 injects powdery supply material 181 to the processing area. The material supply unit 18 can change the material supply speed, which is the speed at which the powdery supply material 181 is supplied onto the workpiece 31 , according to instructions from the control unit 17 . The powdery supply material 181 is supplied toward the processing area, but the supply angle and direction are not particularly limited. The example of FIG. 8 shows a case where a powdery supply material 181 is supplied to the workpiece 31 from obliquely above the workpiece 31 . In Embodiment 3, the powdery feed material 181 is assumed to be metal powder, which is powdery metal. Simultaneously supplying the wire-like feed material 111 and the powder-like feed material 181 to the processing area enables additive manufacturing to be performed while continuously controlling the composition. Here, the wire-like feed material 111 and the powder-like feed material 181 have different chemical compositions. In one example, wire feedstock 111 corresponds to the first feedstock and powder feedstock 181 corresponds to the second feedstock. Also here, the wire feed material 111 has the same composition as the work piece 31 in FIG. Take for example the case of forming

A joint surface of dissimilar materials is generally fragile compared to an interface of similar materials. For this reason, it may cause a processing failure when molding a different material. Therefore, when forming a model on the workpiece 31 with dissimilar materials, if the composition of each layer is changed little by little so that the composition distribution on the bonding surface of the dissimilar materials becomes a gradation, a strong bonding interface can be obtained. known to be obtained. Below, the joint interface whose composition is changed little by little along the gradation is referred to as a gradation layer.

The gradation layer is, in one example, a layer of an alloy of wire-like feed material 111 and powder-like feed material 181 . The composition obtained after heating, melting, and mixing the materials is determined by the heating and cooling paths. That is, it is determined by the temperature process of the weld pool 32 . If the temperature of the molten pool 32 is inappropriate, the alloy will not be alloyed as designed, and metal will precipitate or compounds such as oxides will be generated.

The alloying process is designed by pre-computing the phase diagram for the composition at a certain temperature. To achieve the designed process, it is necessary to keep the temperature constant during processing. Since the additive manufacturing apparatus 1B of Embodiment 3 includes the two-color temperature camera 15 for measuring the temperature of the processing area, the temperature of the molten pool 32 can be accurately measured regardless of the composition of the molten pool 32 as described above. Is possible. The control unit 17 controls the processing parameters as described in the first embodiment so that the measured temperature of the molten pool 32 becomes the temperature in the designed process.

Also, the composition control is achieved by controlling the supply amount ratio of the wire-like feed material 111 and the powdery feed material 181 having a chemical composition different from that of the wire-like feed material 111 . That is, the control unit 17 controls the composition of the additional layer formed by changing the material supply speed of the wire-like supply material 111 and the material supply speed of the powder-like supply material 181 . In addition, the control unit 17 uses the temperature distribution information calculated from the measurement result by the two-color temperature camera 15 to adjust the output of the processing beam B and the scan speed so that the temperature of the molten pool 32 is within a predetermined range. to control. As a result, a strong bonding interface can be obtained when dissimilar materials are modeled. It should be noted that supplying the powder-like supply material 181 and the wire-like supply material 111 at the same time is for forming an interface between different materials. After shaping the dissimilar material interface, wire feed material 111 or powder feed material 181 will be used that is not the material used prior to shaping the dissimilar material interface.

In Embodiment 3, the additional manufacturing apparatus 1B includes a material supply unit 11 that supplies wire-like supply material 111 and a material supply unit 18 that supplies powdery supply material 181 . Based on the measurement result of the two-color temperature camera 15, the control unit 17 adjusts the temperature of the molten pool 32 to the temperature of the process designed in advance based on the phase diagram when shaping the interface of different materials. The processing parameters are controlled as well as the feed ratio between the wire-form feed material 111 and the powder-form feed material 181 . As a result, a three-dimensional model having a strong joint interface of dissimilar materials can be obtained.

In addition, in Embodiments 1 to 3 described above, it has been explained that the wire-like feed material 111 and the powder-like feed material 181 are made of metal. Here, the metal may be not only a material composed of a single metal element, but also an alloy or an intermetallic compound.

Here, the hardware configuration of the control unit 17 of the additional manufacturing apparatuses 1, 1A, and 1B will be described. FIG. 9 is a diagram illustrating an example of a hardware configuration of a control unit of the additive manufacturing apparatus according to Embodiments 1 to 3;

The control unit 17 can be realized by a control circuit 400, that is, a processor 401 and a memory 402 shown in FIG. An example of the processor 401 is a CPU (also referred to as a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, DSP (Digital Signal Processor)) or system LSI (Large Scale Integration). Examples of memory 402 are RAM (Random Access Memory) or ROM (Read Only Memory).

The functions of the control unit 17 are realized by the processor 401 reading out and executing a control program stored in the memory 402 for executing processing in the control unit 17 . Further, it can be said that this control program causes a computer to execute the control method of the additional manufacturing apparatuses 1, 1A, and 1B in the control unit 17. FIG. The control program executed by the control unit 17 calculates the temperature distribution information and the emissivity distribution information of the imaging area from the measurement results of the two-color temperature camera 15, and performs the process of controlling the processing parameters based on the temperature distribution information. These are loaded onto the main memory and generated on the main memory. The processing parameters include the output of the processing beam source 12, the scanning speed of the processing beam B, and the material supply speed of the material supply units 11 and 18.

The memory 402 stores data used when modeling a three-dimensional modeled object. The memory 402 is also used as temporary memory when the processor 401 executes various processes.

The control program executed by the processor 401 may be stored in a computer-readable storage medium in an installable or executable format and provided as a computer program product. Also, the control program executed by processor 401 may be provided to control unit 17 of additional manufacturing apparatuses 1, 1A, and 1B via a network such as the Internet.

Also, the control unit 17 may be realized by dedicated hardware. Also, the functions of the control unit 17 may be partly realized by dedicated hardware and partly by software or firmware.

The configurations shown in the above embodiments are only examples, and can be combined with other known techniques, or can be combined with other embodiments, without departing from the scope of the invention. It is also possible to omit or change part of the configuration.

1, 1A, 1B additional manufacturing device, 11, 18 material supply unit, 12 processing beam source, 13, 13A processing head, 14 optical fiber, 15 two-color temperature camera, 16 display device, 17 control unit, 31 workpiece, 32 molten pool 111, 181 feed material 130 transmission optical system 131 collimating lens 132 preheating optical element 133 reflecting mirror 134 condenser lens B processing beam L, LA, LB laser light SP1, SP2 condenser light spot.

Claims (6)

a first material supply unit that supplies a first supply material having a chemical composition different from that of the workpiece toward a processing area of the workpiece;
a processing beam source that outputs a processing beam that heats the first feed material and the workpiece;
a processing head for irradiating the processing area with the processing beam from the processing beam source;
a two-color temperature camera that captures an imaging region including the processing region with light of at least two wavelength bands;
The imaging including the temperature of the workpiece, the first supply material, and the molten pool in which the workpiece and the first supply material are melted in the processing area, based on the measurement result by the two-color temperature camera. Temperature distribution information indicating the temperature distribution of the region is calculated, and based on the temperature distribution information, the output of the processing beam of the processing beam source, the scan speed that is the speed at which the processing beam is scanned, and the first supply material A control unit that controls processing parameters including at least one selected from a material supply speed that is a supply speed of
An additive manufacturing device comprising: further equipped with a display,
2. The additive manufacturing apparatus according to claim 1 , wherein the control unit displays the temperature distribution information on the display unit. The control unit calculates emissivity distribution information indicating emissivity distribution in an imaging range of the two-color temperature camera based on the temperature distribution information, and displays the emissivity distribution information on the display unit. 3. The additive manufacturing apparatus of claim 2 . 2. The additive manufacturing apparatus according to claim 1 , further comprising a preheating section that heats the first supply material immediately before it is supplied to the processing area. The processing beam is a laser beam,
The processing head has a transmission optical system for condensing the laser light onto the processing area,
The preheating unit is a preheating optical element for condensing part of the laser light focused on the processing area by the transmission optical system onto the first supply material immediately before entering the processing area. 5. The additive manufacturing apparatus of claim 4 . further comprising a second material supply unit that supplies a second supply material having a chemical composition different from that of the first supply material;
The control unit
controlling the composition of an additional layer formed by varying the material feed rate of said first feed material and the material feed rate of said second feed material;
2. The additive manufacturing apparatus according to claim 1 , wherein the temperature distribution information is used to control the output of the processing beam and the scan speed so that the temperature of the molten pool falls within a predetermined range. .

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