Oxygen concentration estimation method and molding system

Abstract

To provide a method capable of estimating an oxygen concentration precisely on an irradiation position of laser beams during laser beam irradiation.SOLUTION: A method for estimating an oxygen concentration includes a step of causing a first laser metal forming device to supply first shield gas within a chamber, to irradiate first base material with laser beams, thereby, to form first beads, to measure an oxygen concentration within the chamber and first bead feature to produce back data provided by associating the oxygen concentration with the first bead feature, and a step of causing a second laser metal forming device to supply the first shield gas to second base material in atmospheric open environment, to form second beads by irradiating the second base material with laser beams, thereby, to form second beads, to measure second bead feature, and to estimate oxygen concentration when the second base material is worked based on back data and the second bead feature.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to an oxygen concentration estimation method and a modeling system for estimating an oxygen concentration during additive manufacturing. [Background technology]

[0002] In additive manufacturing using a modeling device, metal is melted using a laser, arc discharge, etc. In this modeling device, a shielding gas is sprayed onto the processing area to reduce the oxygen concentration in order to prevent oxidation of the molten metal.

[0003] The laser light irradiation device described in Patent Document 1 measures the oxygen concentration in the laser sintering atmosphere and determines the amount of inert gas injected depending on the measured oxygen concentration, thereby adjusting the oxygen concentration to a value below which the substrate does not oxidize and deteriorate, and producing a metal nanoparticle sintered body with excellent adhesion to the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-247181 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technique of Patent Document 1, when the atmospheric gas is sucked in from the tip of the atmospheric gas constant amount inhalation tube connected to the oxygen concentration meter, in order to prevent the atmospheric gas constant amount inhalation tube from coming into contact with the laser light, the distance between the atmospheric gas constant amount inhalation tube and the position irradiated with the laser light becomes long, which causes a problem that the oxygen concentration at the position irradiated with the laser light cannot be accurately measured during the laser light irradiation.

[0006] The present disclosure has been made in consideration of the above, and has an object to provide an oxygen concentration estimation method capable of accurately estimating the oxygen concentration at a laser light irradiation position during laser light irradiation. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the oxygen concentration estimation method of the present disclosure includes a first transport step in which a first base material containing a metal is transported to a first stage in a chamber of a first laser metal sintering apparatus. The oxygen concentration estimation method of the present disclosure also includes a first gas supply step in which a first shielding gas supply device of the first laser metal sintering apparatus supplies a first shielding gas that prevents oxidation of the heated and melted metal into the chamber, and a first bead formation step in which a first processing head of the first laser metal sintering apparatus irradiates the first base material with a laser beam to heat and melt the first base material and form a first bead on the first base material. The oxygen concentration estimation method of the present disclosure also includes a concentration measurement step in which an oxygen meter of the first laser metal sintering apparatus measures the oxygen concentration in the chamber, and a first characteristic measurement step in which a first measurement device of the first laser metal sintering apparatus measures a first bead characteristic that is a characteristic of the first bead. The oxygen concentration estimation method of the present disclosure also includes a back data generation step in which a first control device of the first laser metal sintering apparatus generates back data in which the oxygen concentration is associated with a first bead feature. The oxygen concentration estimation method of the present disclosure also includes a second transport step in which a second base material made of the same material as the first base material is transported to a second stage of the second laser metal sintering apparatus that is disposed in an open-to-air environment. The oxygen concentration estimation method of the present disclosure also includes a second gas supply step in which a second shielding gas supply device of the second laser metal sintering apparatus supplies a first shielding gas to the second base material, and a second bead formation step in which a second processing head of the second laser metal sintering apparatus irradiates the second base material with a laser beam to heat and melt the second base material and form a second bead on the second base material. In addition, the oxygen concentration estimation method disclosed herein includes a second feature measurement step in which a second measuring device possessed by the second laser metal sintering apparatus measures a second bead feature that is a feature of the second bead, and an estimation step in which a second control device possessed by the second laser metal sintering apparatus estimates the oxygen concentration when the second base material is processed based on the back data and the second bead feature. Effect of the Invention

[0008] The oxygen concentration estimation method according to the present disclosure has an effect of being able to accurately estimate the oxygen concentration at the laser light irradiation position during laser light irradiation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of a second laser metal shaping apparatus according to a first embodiment; [Diagram 2] FIG. 10 is a diagram for explaining bead height measurement by the second laser metal shaping apparatus according to the first embodiment; [Diagram 3] FIG. 1 is a diagram showing a configuration of a first laser metal shaping apparatus according to a first embodiment; [Figure 4] 1 is a flowchart showing a procedure of a back data generation process performed by the first laser metal shaping apparatus according to the first embodiment. [Diagram 5] FIG. 1 is a diagram showing a configuration of back data generated by a first laser metal shaping apparatus according to a first embodiment; [Figure 6] FIG. 1 is a diagram for explaining the relationship between oxygen concentration and surface roughness. [Figure 7] 1 is a flowchart showing a procedure of a quality check process performed by the second laser metal shaping apparatus according to the first embodiment. [Figure 8] FIG. 10 is a diagram for explaining a quality check process by the second laser metal shaping apparatus according to the first embodiment; [Figure 9] FIG. 13 is a diagram showing the configuration of a second laser metal shaping apparatus according to a second embodiment. [Figure 10] FIG. 1 shows a configuration of a first laser metal shaping apparatus according to a second embodiment. [Figure 11] 11 is a flowchart showing a procedure of a back data generation process performed by a first laser metal shaping apparatus according to a second embodiment. [Figure 12] FIG. 13 is a diagram showing a configuration of back data generated by the first laser metal shaping apparatus according to the second embodiment; [Figure 13] FIG. 13 is a diagram for explaining a temperature fluctuation range measured by the first and second laser metal shaping apparatuses according to the second embodiment; [Figure 14]FIG. 1 is a diagram for explaining the relationship between oxygen concentration and temperature fluctuation range. [Figure 15] 10 is a flowchart showing a procedure of a quality check process by a second laser metal shaping apparatus according to a second embodiment. [Figure 16] FIG. 1 is a diagram showing the shape of a YZ cross section of a marker base material having a first shape. [Figure 17] FIG. 1 is a diagram showing the shape of an XZ cross section of a marker base material having a first shape; [Figure 18] FIG. 13 is a diagram showing the shape of a YZ cross section of a marker base material having a second shape. [Figure 19] FIG. 13 is a diagram showing the shape of an XZ cross section of a marker base material having a second shape. [Figure 20] FIG. 13 is a top view of a marker base material according to a fourth embodiment in which multiple types of materials are arranged. [Figure 21] FIG. 13 is a diagram showing the shape of an XZ cross section of a marker base material according to a fourth embodiment in which multiple types of materials are arranged. [Figure 22] FIG. 13 is a top view of a marker base material according to a fourth embodiment, in which the composition is continuously changed. [Diagram 23] FIG. 13 is a diagram showing the shape of an XZ cross section of a marker base material according to a fourth embodiment in which the composition is continuously changed. [Figure 24] FIG. 1 is a diagram showing a configuration example of a processing circuit provided in a control device according to the first to fourth embodiments when the processing circuit is realized by a processor and a memory. [Diagram 25] FIG. 1 is a diagram showing an example of a processing circuit included in a control device according to the first to fourth embodiments, in the case where the processing circuit is configured with dedicated hardware; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an oxygen concentration estimation method and a molding system according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] Embodiment 1 The modeling system of the first embodiment includes a first laser metal printing device that generates data used to estimate the oxygen concentration (back data 61 described later), a second laser metal printing device that actually performs additive manufacturing on a base material and estimates the oxygen concentration during additive manufacturing, and a storage device 60 described later. Below, the second laser metal printing device will be described first, and then the first laser metal printing device will be described.

[0012] Fig. 1 is a diagram showing the configuration of a second laser metal shaping apparatus according to the first embodiment. In the following, two axes in a plane parallel to the upper surface of the stage 6 and perpendicular to each other are referred to as the X-axis and the Y-axis. An axis perpendicular to the X-axis and the Y-axis is referred to as the Z-axis. The Z-axis direction is the vertical direction, and the XY plane is the horizontal plane.

[0013] The laser metal printing apparatus 50A, which is the second laser metal printing apparatus, is a printing apparatus that performs shaping processing on a base material 5, which is a workpiece. The laser metal printing apparatus 50A performs additive manufacturing with the base material 5 placed on a stage 6 that is movable in the horizontal direction. The laser metal printing apparatus 50A processes the base material 5 by heating and melting the wire 2 with a processing laser beam 1 and stacking a bead 3 in a processing area 4 on the upper surface of the base material 5. The processing laser beam 1 is a printing laser beam used to stack the beads 3.

[0014] The laser metal shaping apparatus 50A is connected to a storage device 60. The storage device 60 stores back data 61, which is information that associates processing conditions with the oxygen concentration and surface roughness when processing is performed under these processing conditions. In other words, the back data 61 is information that indicates the correspondence between the oxygen concentration and the surface roughness for each processing condition.

[0015] The back data 61 is generated by the laser metal sintering device 50B, which will be described later. Before processing the base material 5, the laser metal sintering device 50A performs processing on a test base material (a marker base material 21, which will be described later) different from the base material 5. The laser metal sintering device 50A estimates the oxygen concentration when the marker base material 21 is processed based on the surface roughness of a bead (an empty bead 24, which will be described later) that is the processing result on the marker base material 21 and the back data 61. If the oxygen concentration when the marker base material 21 is processed is within a specified range, the laser metal sintering device 50A processes the base material 5 under the processing conditions used when the marker base material 21 is processed. This allows the laser metal sintering device 50A to process the base material 5 with an oxygen concentration within the specified range. Details of the back data 61 will be described later. The storage device 60 may be disposed inside the laser metal sintering device 50A or inside the laser metal sintering device 50B.

[0016] The laser metal shaping apparatus 50A includes a wire supplying device 7, a processing head 8, a shielding gas supplying device 9, a gas pipe 16A, a laser oscillator 10, a light transmission path 18, a driving device 11, a control device 12, and a stage 6.

[0017] The wire supplying device 7 supplies the wire 2 to the processing area 4. The processing head 8 irradiates the processing area 4 with the processing laser light 1 and emits a shielding gas 17 to the processing area 4. The processing head 8 has a shielding gas nozzle 13, a laser head 14, and a height measuring device 15.

[0018] The shielding gas supply device 9 supplies the shielding gas 17 to the shielding gas nozzle 13 via the gas piping 16A. The gas piping 16A is connected to the shielding gas supply device 9 and the shielding gas nozzle 13, and sends the shielding gas 17 ejected from the shielding gas supply device 9 to the shielding gas nozzle 13. The shielding gas nozzle 13 ejects the shielding gas 17 into the processing region 4.

[0019] The laser oscillator 10 outputs the processing laser light 1 to the laser head 14 via an optical transmission path 18. The optical transmission path 18 is connected to the laser oscillator 10 and the laser head 14, and transmits the processing laser light 1 emitted from the laser oscillator 10 to the laser head 14.

[0020] The laser head 14 irradiates the processing region 4 with the processing laser light 1 transmitted via the optical transmission path 18. The drive device 11 has a Z-axis drive device that moves the processing head 8 in the Z-axis direction, which is the vertical direction, an X-axis drive device that moves the processing head 8 in the X-axis direction, and a Y-axis drive device that moves the processing head 8 in the Y-axis direction. The drive device 11 moves the processing head 8 to a position specified by the control device 12 by the Z-axis drive device, the X-axis drive device, and the Y-axis drive device.

[0021] The height measuring device 15 measures the height of the bead 3 stacked in the processing area 4 by irradiating the bead 3 with a measuring laser light. The height measuring device 15 sends bead height information indicating the height of the bead 3 to the control device 12. As a result, the control device 12 stacks the beads 3 to a desired height based on the bead height information. In addition, when performing quality control described later, the height measuring device 15 measures the height of the empty bead 24 stacked in the processing area 4 by irradiating the empty bead 24 with a measuring laser light. The empty bead 24 is a mark (processing mark) formed when the base material 5 or the marker base material 21 is heated, melted, and resolidified without supplying the wire 2. The measuring laser light is a laser light used to measure the height of the bead 3 and the empty bead 24. The height of the empty bead 24 corresponds to the surface roughness of the empty bead 24. In the first embodiment, the height measuring device 15 measures the height of the empty bead 24 formed on the marker base material 21 and sends the measurement result to the control device 12 as height information.

[0022] The control device 12 controls the laser oscillator 10, the wire supply device 7, the height measuring device 15, the shielding gas supply device 9, the drive device 11, and the stage 6 so that the bead 3 is deposited in the desired processing area 4.

[0023] Furthermore, the control device 12 calculates the surface roughness indicating the unevenness of the empty bead 24 based on the height information sent from the height measuring device 15. In the first embodiment, the control device 12 forms the empty bead 24 on the marker base material 21 before starting processing of the base material 5, and calculates the unevenness (surface roughness) of the empty bead 24. The control device 12 calculates the oxygen concentration when the empty bead 24 is being formed based on the surface roughness of the empty bead 24.

[0024] 2 is a diagram for explaining bead height measurement by the second laser metal shaping apparatus according to the first embodiment. Height measuring device 15 is driven by driving device 11 to move to a measurement position for bead 3. Height measuring device 15 irradiates measurement laser light 19 from above bead 3 whose height is to be measured, and receives the reflected light of measurement laser light 19.

[0025] The height measuring device 15 measures the height of the bead 3 by irradiating the bead 3 with a measuring laser beam 19 along the direction in which the bead 3 is stacked. The height measuring device 15 sends height information indicating the height of the bead 3 to the control device 12. Based on the height information sent from the height measuring device 15, the control device 12 calculates the surface roughness indicating the unevenness of the bead 3 after molding.

[0026] In the first embodiment, the laser metal sintering apparatus 50B generates the background data 61. The laser metal sintering apparatus 50A calculates the oxygen concentration when the processing laser beam 1 is irradiated using the background data 61 while laminating the beads 3.

[0027] If the oxygen concentration when the marker base material 21 is processed is within a specified range, the control device 12 controls the laser oscillator 10, the shielding gas supply device 9, and the drive device 11 so as to achieve the processing conditions used when the marker base material 21 was processed. In this way, the laser metal sintering apparatus 50A controls the oxygen concentration to be within the specified range and then performs additive manufacturing on the base material 5. Since the laser metal sintering apparatus 50A performs additive manufacturing on the base material 5 under the same processing conditions as the processing conditions of the marker base material 21, it can be estimated that the oxygen concentration when additive manufacturing on the base material 5 is performed is the same as the oxygen concentration when additive manufacturing on the marker base material 21 is performed.

[0028] In the first embodiment, by using the laser metal shaping apparatuses 50A and 50B, it is possible to estimate the oxygen concentration in the processing area 4 being irradiated with the processing laser light 1, which was conventionally difficult.

[0029] Next, a quality control method according to the first embodiment will be described. The quality control method according to the first embodiment includes a back data acquisition flow and a quality check flow. First, the back data acquisition flow will be described.

[0030] 3 is a diagram showing the configuration of a first laser metal shaping apparatus according to the embodiment 1. The first laser metal shaping apparatus, 50B, is a shaping apparatus that generates back data 61, which is information used when estimating the oxygen concentration during shaping processing of the base material 5.

[0031] The laser metal sintering apparatus 50B, which is a first laser metal sintering apparatus, includes a chamber 20 and an oxygen concentration meter 23 in addition to the components included in the laser metal sintering apparatus 50A, but does not include a wire supply device 7. Furthermore, the laser metal sintering apparatus 50B includes a gas pipe 16B instead of the gas pipe 16A. That is, the laser metal sintering apparatus 50B includes a chamber 20, an oxygen concentration meter 23, a processing head 8, a shielding gas supply device 9, a gas pipe 16B, a laser oscillator 10, an optical transmission path 18, a drive device 11, a control device 12, and a stage 6.

[0032] In the laser metal shaping apparatus 50B, a driving device 11, a height measuring device 15, and a processing head 8 are arranged in a chamber 20 where the shaping process is performed. The chamber 20 has a wall surface surrounding a shaping room where the shaping process is performed. The inside of the chamber 20 is a closed space in which a shielding gas 17 is sealed. The chamber 20 is in an environment where the oxygen concentration can be controlled.

[0033] The chamber 20 is connected to a shielding gas supplying device 9 via a gas pipe 16B. That is, the shielding gas supplying device 9 supplies a shielding gas 17 (not shown in FIG. 3) to the chamber 20 via the gas pipe 16B. The shielding gas 17 supplied from the shielding gas supplying device 9 is released into the chamber 20, thereby reducing the oxygen concentration in the chamber 20.

[0034] Furthermore, the chamber 20 is connected to an oxygen concentration meter 23 via a gas inlet pipe 22. The atmosphere inside the chamber 20 is taken into the oxygen concentration meter 23 via the gas inlet pipe 22. The oxygen concentration meter 23 measures the oxygen concentration contained in the atmosphere inside the chamber 20. The oxygen concentration meter 23 sends the measured oxygen concentration to the control device 12.

[0035] The control device 12 increases or decreases the shielding gas supply amount [l / min] of the shielding gas supply device 9 based on the oxygen concentration sent from the oxygen concentration meter 23, thereby increasing or decreasing the oxygen concentration in the chamber 20. The control device 12 controls the shielding gas supply amount so that the oxygen concentration in the chamber 20 becomes a specific oxygen concentration.

[0036] The laser metal sintering apparatus 50B does not include a wire supplying device 7. The laser metal sintering apparatus 50B irradiates the marker base material 21 with the processing laser light 1 without supplying the wire 2 to the base material 5. The laser metal sintering apparatus 50B irradiates the marker base material 21 with the processing laser light 1 while controlling the inside of the chamber 20 to a specific oxygen concentration. The marker base material 21 is a base material used when generating back data 61 indicating the correspondence between the oxygen concentration in the chamber 20 and the surface roughness of the empty bead 24. The laser metal sintering apparatus 50B generates the back data 61 by performing shaping processing on the marker base material 21 under various processing conditions and various oxygen concentrations.

[0037] The stage 6 provided in the laser metal sintering apparatus 50B is the first stage, and the stage 6 provided in the laser metal sintering apparatus 50A is the second stage. The shielding gas supply device 9 provided in the laser metal sintering apparatus 50B is the first shielding gas supply device, and the shielding gas supply device 9 provided in the laser metal sintering apparatus 50A is the second shielding gas supply device.

[0038] The shielding gas 17 supplied by the shielding gas supply device 9 of the laser metal sintering apparatus 50B is the first shielding gas, and the shielding gas 17 supplied by the shielding gas supply device 9 of the laser metal sintering apparatus 50A is the second shielding gas. The processing head 8 provided in the laser metal sintering apparatus 50B is the first processing head, and the processing head 8 provided in the laser metal sintering apparatus 50A is the second processing head.

[0039] The height measuring device 15 included in the laser metal sintering apparatus 50B is a first measuring device (first height measuring device), and the height measuring device 15 included in the laser metal sintering apparatus 50A is a second measuring device (second height measuring device).

[0040] The shape of the empty bead 24 measured by the height measuring device 15 of the laser metal sintering apparatus 50B is the first bead feature, and the shape of the empty bead 24 measured by the height measuring device 15 of the laser metal sintering apparatus 50A is the second bead feature. That is, in the first embodiment, the bead feature that is characteristic of the empty bead 24 is the shape of the empty bead 24. The control device 12 provided in the laser metal sintering apparatus 50B is the first control device, and the control device 12 provided in the laser metal sintering apparatus 50A is the second control device.

[0041] In the first embodiment, the height measuring device 15 measures the height of the empty bead 24, but any of the laser metal shaping devices 50A, 50B may measure the shape of the empty bead 24 as long as it can measure the shape of the empty bead 24. Examples of the shape of the empty bead 24 include the height, top area, bottom area, and volume of the empty bead 24.

[0042] 4 is a flowchart showing the procedure of the back data generation process by the first laser metal sintering apparatus according to the embodiment 1. The laser metal sintering apparatus 50B transports the marker base material 21 selected by the user and places it on the stage 6. The marker base material 21 is made of a metal added with an aluminum alloy, a titanium alloy, a nickel alloy, a copper alloy, an iron alloy, an alkali metal, or an alkaline earth metal.

[0043] The laser metal shaping apparatus 50B controls the oxygen concentration in the chamber 20 to a specific value (step S10). Specifically, the control device 12 controls the shielding gas supply device 9 to supply the shielding gas 17 to the chamber 20. The control device 12 refers to the oxygen concentration measured by the oxygen concentration meter 23 and controls the shielding gas supply device 9 to achieve a desired oxygen concentration.

[0044] The laser metal sintering apparatus 50B starts processing the marker base material 21 when the oxygen concentration in the chamber 20 reaches a specific value (step S20). That is, the laser metal sintering apparatus 50B starts sintering processing on the marker base material 21 when the oxygen concentration in the chamber 20 is constant.

[0045] The laser metal shaping apparatus 50B irradiates the marker base material 21 with the processing laser beam 1, thereby heating and melting the marker base material 21 with the processing laser beam 1, thereby forming an empty bead 24 in the marker base material 21.

[0046] In this manner, the laser metal sintering apparatus 50B forms the hollow bead 24 in the marker base material 21 at a specific oxygen concentration without supplying the wire 2. In the first embodiment, the marker base material 21 processed by the laser metal sintering apparatus 50B is the first base material, and the hollow bead 24 formed in the marker base material 21 by the laser metal sintering apparatus 50B is the first bead.

[0047] The laser metal sintering apparatus 50B measures the processing conditions during processing. Specifically, the laser metal sintering apparatus 50B measures the laser output P, ​​the laser irradiation diameter A, and the head movement speed v, which is the movement speed of the processing head 8, during processing (step S30). Note that the laser metal sintering apparatus 50B may actually measure the laser output P, ​​the laser irradiation diameter A, and the head movement speed v, or may adopt values ​​set as the processing conditions as the measured values.

[0048] After processing, the laser metal sintering apparatus 50B measures the surface roughness R [μm] of the empty bead 24 using the height measuring device 15 (step S40). The laser metal sintering apparatus 50B records a parameter set including the oxygen concentration C, the laser output P, ​​the laser irradiation diameter A, the head moving speed v, and the surface roughness R in the back data 61 in the storage device 60 (step S50).

[0049] Here, the configuration of the back data 61 will be described. Fig. 5 is a diagram showing the configuration of the back data generated by the first laser metal shaping apparatus according to the first embodiment. The back data 61 includes a data number, a marker base material type (the type of the marker base material 21), a laser output P [W], a laser irradiation diameter A [mm 2 ], head movement speed v [mm / min], oxygen concentration C [PPM], and surface roughness R are associated with each other.

[0050] The data number is a number assigned to one processing operation, that is, in the back data 61, one data number is assigned to one processing operation of steps S10 to S50.

[0051] In the back data 61, the marker base material type, the laser output P, ​​the laser irradiation diameter A, the head movement speed v, and the oxygen concentration C are processing conditions. The surface roughness R is data indicating the processing result. In the back data 61, one data number, one marker base material type, one laser output P, ​​one laser irradiation diameter A, one head movement speed v, and one oxygen concentration C are associated with each other to form one parameter set 62. The laser metal sintering apparatus 50B acquires a plurality of parameter sets 62 by performing processing under various processing conditions. The laser metal sintering apparatus 50B stores each acquired parameter set 62 in the back data 61.

[0052] The back data 61 may include a bead length l [mm], which is the length of the empty bead 24. The bead length l is data indicating the result of processing. In addition, when the marker base material type, the laser output P, ​​the laser irradiation diameter A, and the head movement speed v are fixed, the back data 61 does not need to include the marker base material type, the laser output P, ​​the laser irradiation diameter A, and the head movement speed v.

[0053] The control device 12 of the laser metal shaping apparatus 50B determines whether or not processing has been performed under all of the assumed combinations of processing conditions and oxygen concentrations C (step S60).

[0054] If the control device 12 has not executed machining for all combinations (step S60, No), it changes the combination of the machining conditions and the oxygen concentrations C (step S70). That is, the control device 12 changes the current combination of the machining conditions and the oxygen concentrations C to an unused combination among the combinations prepared in advance.

[0055] After that, the laser metal sintering apparatus 50B repeats the processes of steps S10 to S70 until processing has been executed for all combinations. When processing has been executed for all combinations (step S60, Yes), the laser metal sintering apparatus 50B ends the back data generation process.

[0056] The laser metal shaping apparatus 50B generates back data 61 by varying the oxygen concentration C. Here, the relationship between the oxygen concentration C and the surface roughness R in the marker base material 21 will be described. FIG. 6 is a diagram for explaining the relationship between the oxygen concentration and the surface roughness. The horizontal axis of the graph shown in FIG. 6 is the oxygen concentration C, and the vertical axis is the surface roughness R. In FIG. 6, the relationship between the oxygen concentration C and the surface roughness R is shown as a correspondence relationship 81.

[0057] When the oxygen concentration C of the marker base material 21 is increased, the surface roughness R increases. That is, when the marker base material 21 is processed, the surface roughness R also increases with an increase in the oxygen concentration C. As shown by the correspondence relationship 81, in a region where the oxygen concentration C is lower than a specific value, a dead region 71 is formed in which the surface roughness R hardly changes even if the oxygen concentration C increases. When the oxygen concentration C increases beyond the dead region 71, a reaction region 72 is formed in which the surface roughness R changes with respect to the change in the oxygen concentration C. When the oxygen concentration C increases further beyond the reaction region 72, a saturation region 73 is formed in which the surface roughness R hardly changes even if the oxygen concentration C increases. That is, in the saturation region 73, the variation in the surface roughness R is small even if the oxygen concentration C changes.

[0058] In this way, when the oxygen concentration C is high, the molten metal reacts with oxygen, forming high-melting-point oxides (e.g., titanium oxide) on the surface of the marker base material 21. These oxides inhibit uniform solidification and melt flow (convection within the molten pool) of the molten metal. For this reason, the surface roughness R and the temperature fluctuation range ΔT, which will be described later, change depending on the oxygen concentration C.

[0059] The dead region 71, the responsive region 72, and the saturated region 73 differ depending on the material of the marker base material 21. Furthermore, the dead region 71, the responsive region 72, and the saturated region 73 also depend on the laser output P, ​​the laser irradiation diameter A, and the head moving speed v.

[0060] The laser metal sintering apparatus 50B builds back data 61, which is a collection of parameter sets 62, by repeatedly processing the marker base material 21 while changing the combination of processing conditions and oxygen concentration C. The parameters used during actual additive manufacturing are set as the laser output P, ​​the laser irradiation diameter A, and the head movement speed v. That is, the laser output P, ​​the laser irradiation diameter A, and the head movement speed v used by the laser metal sintering apparatus 50A during additive manufacturing are set in the laser metal sintering apparatus 50B, and the back data 61 is generated.

[0061] Furthermore, the oxygen concentration C is set within a range that can reduce the oxygen concentration C in the processing area 4 when the shielding gas nozzle 13 sprays the shielding gas 17 toward the processing area 4. For example, if the oxygen concentration C in the processing area 4 can be reduced to a minimum of 100 PPM by the shielding gas nozzle 13, the laser metal shaping apparatus 50B sets the parameter of the oxygen concentration C to 100 PPM or more.

[0062] Next, the quality check process by the laser metal sintering apparatus 50A will be described. Fig. 7 is a flowchart showing the procedure of the quality check process by the second laser metal sintering apparatus according to the first embodiment. Fig. 8 is a diagram for explaining the quality check process by the second laser metal sintering apparatus according to the first embodiment.

[0063] The laser metal sintering apparatus 50A sets the processing conditions designated by the user in the control device 12. Specifically, the laser metal sintering apparatus 50A extracts the same processing conditions as those used to process the base material 5 from the back data 61, and sets them as the processing conditions to be used to process the marker base material 21.

[0064] The laser metal sintering apparatus 50A places a base material 5 and a marker base material 21 on the upper surface of a stage 6. The base material 5 is used for additive manufacturing, and the marker base material 21 is used to estimate the oxygen concentration C. The base material 5 and the marker base material 21 are the same type of material. In the first embodiment, the marker base material 21 processed by the laser metal sintering apparatus 50A is the second base material.

[0065] The shielding gas supply device 9 sends the shielding gas 17 to the shielding gas nozzle 13 via the gas pipe 16A. The shielding gas nozzle 13 sprays the shielding gas 17 onto the processing region 4 of the marker base material 21.

[0066] The laser metal sintering apparatus 50A starts processing the marker base material 21 in an open-to-atmosphere environment using the set processing conditions (step S110). FIG. 8 shows a state in which the laser metal sintering apparatus 50A is processing the marker base material 21.

[0067] Like the laser metal sintering apparatus 50B, the laser metal sintering apparatus 50A irradiates the marker base material 21 with the processing laser beam 1 without supplying the wire 2, thereby forming an empty bead 24 in the marker base material 21. In the first embodiment, the empty bead 24 formed in the marker base material 21 by the laser metal sintering apparatus 50A is the second bead.

[0068] The laser metal sintering apparatus 50A records the set processing conditions. Specifically, the laser metal sintering apparatus 50A records the laser output P, ​​the laser irradiation diameter A, and the head movement speed v during processing (step S120). Note that the laser metal sintering apparatus 50A may execute the process of step S120 before starting processing of the marker base material 21.

[0069] After processing the marker base material 21, i.e., after forming the hollow bead 24, the laser metal forming apparatus 50A measures the surface roughness R of the hollow bead 24 by the height measuring device 15 (step S130). The height measuring device 15 sends height information indicating the surface roughness R of the hollow bead 24 to the control device 12.

[0070] The control device 12 estimates the oxygen concentration C based on the processing conditions used for processing the marker base material 21, the surface roughness R of the empty bead 24 formed on the marker base material 21, and the back data 61 (step S140). That is, the control device 12 estimates the oxygen concentration C based on the laser output P, ​​the laser irradiation diameter A, the head moving speed v, the surface roughness R, and the back data 61. Specifically, the control device 12 searches and extracts a parameter set 62 including the laser output P, ​​the laser irradiation diameter A, the head moving speed v, and the surface roughness R when the marker base material 21 was processed from the back data 61. The control device 12 estimates that the oxygen concentration C included in the extracted parameter set 62 is the oxygen concentration C when the marker base material 21 was processed.

[0071] The control device 12 determines whether the estimated oxygen concentration C is within a preset range (for example, 100 PPM or less) (step S150). If the estimated oxygen concentration C is not within the range (step S150, No), the flow rate of the shielding gas is adjusted or the inside of the shielding gas nozzle 13 is inspected for foreign matter (step S160).

[0072] When the shielding gas flow rate is adjusted, the control device 12 increases or decreases the flow rate of the shielding gas 17 supplied from the shielding gas supply device 9. The control device 12 may increase or decrease the flow rate of the shielding gas 17 according to an instruction from a user, or may increase or decrease the flow rate of the shielding gas 17 based on an estimated oxygen concentration C.

[0073] After adjusting the shielding gas flow rate or checking for foreign matter in the shielding gas nozzle 13, the laser metal sintering apparatus 50A executes the processes of steps S110 to S150. The laser metal sintering apparatus 50A repeats the processes of steps S110 to S160 until the estimated oxygen concentration C falls within a specified range.

[0074] If the estimated oxygen concentration C is within the specified range (step S150, Yes), the laser metal sintering apparatus 50A processes the base material 5 under processing conditions when the estimated oxygen concentration C falls within the specified range (step S170). In other words, the laser metal sintering apparatus 50A performs additive manufacturing on the base material 5 under the processing conditions used for the marker base material 21 when the estimated oxygen concentration C falls within the specified range.

[0075] The laser metal sintering apparatus 50A performs additive manufacturing on the base material 5 when the estimated oxygen concentration C falls within a specified range, and therefore can process the base material 5 with an oxygen concentration C within the specified range. This allows the laser metal sintering apparatus 50A to prevent defects caused by oxidation of the molten metal when processing the base material 5, and can accurately manage the quality of the marker base material 21.

[0076] The laser metal sintering apparatus 50A may execute the processes of steps S110 to S160 again after additive manufacturing of the base material 5 for a specific time, or after the additive manufacturing is completed. This allows the laser metal sintering apparatus 50A to confirm that the shielding gas 17 has been normally supplied even after processing of the base material 5. Furthermore, the laser metal sintering apparatus 50A processes the marker base material 21 before and after shaping into the base material 5, and estimates the oxygen concentration C and checks for defects in the oxygen concentration C, thereby enabling the quality of the marker base material 21 to be managed more accurately.

[0077] If the estimated oxygen concentration C does not fall within the specified range even after the shielding gas flow rate has been adjusted a specific number of times, a check for foreign matter in the shielding gas nozzle 13 may be performed. In other words, if the oxygen concentration C does not improve by adjusting the shielding gas flow rate, a check for foreign matter that has entered the shielding gas nozzle 13, the presence or absence of scratches in the flow path of the shielding gas nozzle 13, etc. may be performed.

[0078] In this way, the laser metal shaping apparatus 50A of the first embodiment estimates the oxygen concentration C for the marker base material 21, evaluates the oxygen concentration C, and performs processing on the base material 5 if the oxygen concentration C is within a specified range. If the oxygen concentration C is outside the specified range, measures to deal with the defect, such as adjusting the shielding gas flow rate and checking for foreign matter in the shielding gas nozzle 13, are taken.

[0079] When attempting to measure the oxygen concentration C while the base material 5 is being processed, the oxygen concentration meter 23 is brought close to the irradiation position of the processing laser light 1, or the oxygen concentration C is measured using the oxygen concentration meter 23 without irradiating the processing laser light 1.

[0080] However, during irradiation with the processing laser beam 1, it is difficult to bring the oxygen concentration meter 23 close to the irradiation position of the processing laser beam 1, so the oxygen concentration C is measured from a position away from the irradiation position. There is also a method in which the tip of a suction tube is brought close to the irradiation position, air at the irradiation position is sucked in by the suction tube, and the oxygen concentration C of the sucked in air is measured. With this method, the oxygen concentration C cannot be measured accurately due to disturbances caused by the air suction by the suction tube.

[0081] In addition, the oxygen concentration C measured without irradiating the processing laser beam 1 is a value different from the oxygen concentration C when irradiating the processing laser beam 1. For this reason, the oxygen concentration C measured without irradiating the processing laser beam 1 is inaccurate as the oxygen concentration C when irradiating the processing laser beam 1. In this way, it is difficult to measure the accurate oxygen concentration C at the irradiation position during irradiation with the processing laser beam 1.

[0082] In the first embodiment, the laser metal sintering apparatus 50A estimates the oxygen concentration C using the marker base material 21, and when the oxygen concentration C is within a specified range, processes the base material 5. That is, in the first embodiment, the laser metal sintering apparatus 50B processes the marker base material 21 under various processing conditions and measures the surface roughness R of the empty bead 24. Then, the laser metal sintering apparatus 50B generates back data 61 in which the processing conditions used to process the marker base material 21, the oxygen concentration C, and the surface roughness R of the empty bead 24 are associated with each other.

[0083] The laser metal sintering apparatus 50A also processes the marker base material 21 and measures the surface roughness R of the empty bead 24. The laser metal sintering apparatus 50A then estimates the oxygen concentration C based on the surface roughness R and the back data 61, and processes the base material 5 if the oxygen concentration C is within a specified range.

[0084] This allows the laser metal sintering apparatus 50A to process the base material 5 while controlling the oxygen concentration C at the irradiation position during irradiation with the processing laser beam 1 to a desired oxygen concentration C. Therefore, the laser metal sintering apparatus 50A can prevent oxidation of the base material 5 and perform high-quality processing.

[0085] As described above, in the first embodiment, the laser metal sintering apparatus 50B uses the marker base material 21 to generate back data 61 in which the oxygen concentration C corresponds to the surface roughness R of the empty bead 24. Then, the laser metal sintering apparatus 50A processes the marker base material 21 to measure the surface roughness R of the empty bead 24, and estimates the oxygen concentration C based on the surface roughness R and the back data 61. This enables the laser metal sintering apparatus 50A to accurately estimate the oxygen concentration C at the irradiation position during irradiation with the processing laser beam 1.

[0086] In addition, even if an abnormality occurs in the supply of the shielding gas 17 during additive manufacturing and the oxygen concentration C in the processing area 4 increases, the laser metal printing apparatus 50A can estimate the oxygen concentration C by measuring the surface roughness R after processing.

[0087] Embodiment 2 Next, a second embodiment will be described with reference to Fig. 9 to Fig. 15. In the second embodiment, the temperature fluctuation range of the processing region 4 is included in the back data 61 instead of the surface roughness R. In the following, the description of the same contents as in the first embodiment will be omitted, and only the contents different from the first embodiment will be described.

[0088] Fig. 9 is a diagram showing the configuration of a second laser metal sintering apparatus according to embodiment 2. Among the components in Fig. 9, those that achieve the same functions as those in laser metal sintering apparatus 50A, which is the second laser metal sintering apparatus according to embodiment 1 shown in Fig. 1, are given the same reference numerals, and duplicated explanations will be omitted.

[0089] A laser metal sintering apparatus 51A, which is a second laser metal sintering apparatus of the second embodiment, includes a radiation thermometer 25 in addition to the components included in the laser metal sintering apparatus 50A. The radiation thermometer 25 is disposed, for example, in the vicinity of the processing head 8. Moreover, the laser metal sintering apparatus 51A does not include a height measuring device 15.

[0090] The radiation thermometer 25 measures the temperature of the processing area 4 by measuring the radiation of the processing area 4. The radiation thermometer 25 sends the measured temperature of the processing area 4 to the control device 12. In the laser metal shaping apparatus 51A, the control device 12 controls the radiation thermometer 25. The control device 12 calculates a temperature fluctuation range ΔT, which is the fluctuation range of the temperature in the processing area 4, based on the temperature of the processing area 4 measured by the radiation thermometer 25.

[0091] The laser metal sintering apparatus 51A of the second embodiment estimates the oxygen concentration C when shaping processing is performed on the marker base material 21 based on the temperature fluctuation width ΔT and the back data 61. In this way, the laser metal sintering apparatus 51A estimates the oxygen concentration C when shaping processing is performed on the base material 5.

[0092] Fig. 10 is a diagram showing the configuration of a first laser metal sintering apparatus according to embodiment 2. Among the components in Fig. 10, those that achieve the same functions as those in laser metal sintering apparatus 50B, which is the first laser metal sintering apparatus according to embodiment 1 shown in Fig. 3, are given the same reference numerals, and duplicated explanations will be omitted.

[0093] Laser metal sculpting apparatus 51B, which is a first laser metal sculpting apparatus of the second embodiment, is equipped with a radiation thermometer 25 in addition to the components equipped in laser metal sculpting apparatus 50B. The radiation thermometer 25 is disposed, for example, near the processing head 8. That is, within the chamber 20 of the laser metal sculpting apparatus 51B, the processing head 8, the drive device 11, the radiation thermometer 25, and the stage 6 are disposed. Furthermore, the laser metal sculpting apparatus 51B does not include a height measuring device 15.

[0094] The radiation thermometer 25 included in the laser metal sintering apparatus 51B is a first measuring device (first thermometer), and the radiation thermometer 25 included in the laser metal sintering apparatus 51A is a second measuring device (second thermometer).

[0095] The temperature of the processing area 4 measured by the radiation thermometer 25 provided in the laser metal sintering apparatus 51B is the first bead feature, and the temperature of the processing area 4 measured by the radiation thermometer 25 provided in the laser metal sintering apparatus 51A is the second bead feature. In the second embodiment, the first bead feature is the first temperature, and the second bead feature is the second temperature.

[0096] Moreover, the processing area 4 where the radiation thermometer 25 included in the laser metal sintering apparatus 51B measures the temperature is the first processing area. The processing area 4 where the radiation thermometer 25 included in the laser metal sintering apparatus 51A measures the temperature is the second processing area.

[0097] The laser metal sintering apparatus 51B of the second embodiment generates back data 61 including a temperature fluctuation width ΔT. The laser metal sintering apparatus 51B generates the back data 61 by variously changing the oxygen concentration C, similar to the laser metal sintering apparatus 51B.

[0098] 11 is a flowchart showing a procedure of a back data generation process by the first laser metal sintering apparatus according to the embodiment 2. The laser metal sintering apparatus 51B transports and places on the stage 6 the marker base material 21 selected by the user.

[0099] The laser metal sintering apparatus 51B controls the oxygen concentration C in the chamber 20 to a specific value (step S210). The laser metal sintering apparatus 51B starts processing the marker base material 21 when the oxygen concentration C in the chamber 20 has reached the specific value (step S220). The laser metal sintering apparatus 51B forms an empty bead 24 in the marker base material 21 at the specific oxygen concentration C without supplying the wire 2.

[0100] In the second embodiment, the marker base material 21 processed by the laser metal sintering apparatus 51B is the first base material. Also, in the second embodiment, the hollow bead 24 formed in the marker base material 21 by the laser metal sintering apparatus 51B is the first bead. Furthermore, the temperature fluctuation width ΔT when the hollow bead 24 is formed by the laser metal sintering apparatus 51B is the first bead characteristic.

[0101] The laser metal sintering apparatus 51B measures the processing conditions during processing. Specifically, the laser metal sintering apparatus 51B measures the laser output P, ​​the laser irradiation diameter A, the head movement speed v, and the temperature fluctuation range ΔT during processing (step S230). The laser metal sintering apparatus 51B measures the temperature fluctuation range ΔT using the radiation thermometer 25. Note that the laser metal sintering apparatus 51B may actually measure the laser output P, ​​the laser irradiation diameter A, and the head movement speed v, or may adopt values ​​set as the processing conditions as the measured values.

[0102] The laser metal forming apparatus 51B records a parameter set 62 including the oxygen concentration C, the laser output P, ​​the laser irradiation diameter A, the head moving speed v, and the temperature fluctuation width ΔT in the back data 61 in the storage device 60 (step S240).

[0103] 12 is a diagram showing the configuration of back data generated by the first laser metal shaping apparatus according to the embodiment 2. Back data 61 according to the embodiment 2 is data in which a data number, a marker base material type, a laser output P, ​​a laser irradiation diameter A, a head moving speed v, an oxygen concentration C, and a temperature fluctuation width ΔT are associated with each other.

[0104] Here, the temperature fluctuation range ΔT will be explained. Fig. 13 is a diagram for explaining the temperature fluctuation range measured by the first and second laser metal shaping apparatuses according to the second embodiment. The horizontal axis of the graph shown in Fig. 13 is time t, and the vertical axis is temperature T of the processing area 4. In Fig. 13, the relationship between the temperature T of the processing area 4 and time t is shown by a correspondence relationship 82.

[0105] The temperature fluctuation range ΔT is defined by the temperature fluctuation over time in the processing area 4. Since the temperature T is not stable during a start period 74 (e.g., one second from the start), which is a specific period from the start of processing, the laser metal shaping apparatus 51B excludes this period from the measurement of the temperature fluctuation range ΔT. In other words, the temperature fluctuation range ΔT is the fluctuation range of the temperature T after the start period 74 has elapsed. Specifically, the temperature fluctuation range ΔT is the difference between the maximum value of the temperature T and the minimum value of the temperature T after the start period 74 has elapsed.

[0106] Fig. 14 is a diagram for explaining the relationship between the oxygen concentration and the temperature fluctuation range. The horizontal axis of the graph shown in Fig. 14 is the oxygen concentration C, and the vertical axis is the temperature fluctuation range ΔT. In Fig. 14, the relationship between the oxygen concentration C and the temperature fluctuation range ΔT is shown as a correspondence relationship 83.

[0107] 14, as the oxygen concentration C increases, the temperature fluctuation range ΔT also increases. That is, when the marker base material 21 is processed, the temperature fluctuation range ΔT increases as the oxygen concentration C increases, as well as the surface roughness R.

[0108] As shown by correspondence 83, in a region where the oxygen concentration C is lower than a specific value, there is an insensitive region 75 where there is almost no change in the temperature fluctuation width ΔT even if the oxygen concentration C increases. When the oxygen concentration C increases beyond the insensitive region 75, there is a reactive region 76 where there is a change in the temperature fluctuation width ΔT in response to a change in the oxygen concentration C. When the oxygen concentration C increases further beyond the reactive region 76, there is a saturated region 77 where there is almost no change in the temperature fluctuation width ΔT even if the oxygen concentration C increases. That is, in the saturated region 77, there is little change in the temperature fluctuation width ΔT even if the oxygen concentration C changes.

[0109] The dead region 75, the reaction region 76, and the saturation region 77 differ depending on the material of the marker base material 21. Furthermore, the dead region 75, the reaction region 76, and the saturation region 77 also depend on the laser output P, ​​the laser irradiation diameter A, and the head moving speed v.

[0110] The control device 12 of the laser metal shaping apparatus 51B determines whether or not processing has been performed with all of the assumed combinations of processing conditions and oxygen concentrations C (step S250). If processing has not been performed with all combinations (step S250, No), the control device 12 changes the combination of processing conditions and oxygen concentrations C (step S260). That is, the control device 12 changes the current combination of processing conditions and oxygen concentrations C to an unused combination among the combinations prepared in advance.

[0111] After that, the laser metal shaping apparatus 51B repeats the processes of steps S210 to S260 until processing has been executed for all combinations. When processing has been executed for all combinations (step S250, Yes), the laser metal shaping apparatus 51B ends the back data generation process.

[0112] Next, a quality check process by the laser metal sintering apparatus 51A will be described below. Fig. 15 is a flowchart showing a process procedure of the quality check process by the second laser metal sintering apparatus according to the second embodiment.

[0113] The laser metal sintering apparatus 51A sets the processing conditions designated by the user in the control device 12. Specifically, the laser metal sintering apparatus 51A extracts the same processing conditions as those used to process the base material 5 from the back data 61, and sets them as the processing conditions to be used to process the marker base material 21.

[0114] The laser metal sintering apparatus 51A places the base material 5 and the marker base material 21 on the upper surface of the stage 6. In the second embodiment, the marker base material 21 processed by the laser metal sintering apparatus 51A is a second base material.

[0115] The shielding gas supply device 9 sends the shielding gas 17 to the shielding gas nozzle 13 via the gas pipe 16A. The shielding gas nozzle 13 sprays the shielding gas 17 onto the processing region 4 of the marker base material 21.

[0116] The laser metal sintering apparatus 51A starts processing the marker base material 21 in an open-to-air environment using the set processing conditions (step S310). Like the laser metal sintering apparatus 51B, the laser metal sintering apparatus 51A irradiates the marker base material 21 with the processing laser light 1 without supplying the wire 2, thereby forming an empty bead 24 in the marker base material 21.

[0117] In the second embodiment, the empty bead 24 formed in the marker base material 21 by the laser metal sintering apparatus 51A is the second bead, and the temperature fluctuation range ΔT when the empty bead 24 is formed by the laser metal sintering apparatus 51A is the second bead characteristic. That is, in the second embodiment, the bead characteristic that is a characteristic of the empty bead 24 is the temperature fluctuation range ΔT.

[0118] The laser metal sintering apparatus 51A records the set processing conditions and temperature fluctuation range ΔT. Specifically, the laser metal sintering apparatus 51A records the laser output P, ​​the laser irradiation diameter A, the head moving speed v, and the temperature fluctuation range ΔT during processing (step S320). The laser metal sintering apparatus 51A measures the temperature fluctuation range ΔT using the radiation thermometer 25. Note that the laser metal sintering apparatus 51A may record the processing conditions before starting processing of the marker base material 21.

[0119] After processing the marker base material 21, i.e., after forming the empty bead 24, the laser metal shaping apparatus 51A estimates the oxygen concentration C based on the processing conditions used for processing the marker base material 21, the temperature fluctuation width ΔT during processing, and the back data 61 (step S330). That is, the control device 12 estimates the oxygen concentration C based on the laser output P, ​​the laser irradiation diameter A, the head movement speed v, the temperature fluctuation width ΔT, and the back data 61. Specifically, the control device 12 searches and extracts a parameter set 62 including the laser output P, ​​the laser irradiation diameter A, the head movement speed v, and the temperature fluctuation width ΔT when the marker base material 21 was processed from the back data 61. The control device 12 estimates that the oxygen concentration C included in the extracted parameter set 62 is the oxygen concentration C when the marker base material 21 was processed.

[0120] The control device 12 determines whether the estimated oxygen concentration C is within a preset range (e.g., 100 PPM or less) (step S340). If the estimated oxygen concentration C is not within the range (No in step S340), the flow rate of the shielding gas is adjusted or the inside of the shielding gas nozzle 13 is inspected for foreign matter (step S350).

[0121] After adjusting the shielding gas flow rate or checking for foreign matter in the shielding gas nozzle 13, the laser metal sintering apparatus 51A executes the processes of steps S310 to S340. The laser metal sintering apparatus 51A repeats the processes of steps S310 to S350 until the estimated oxygen concentration C falls within a specified range.

[0122] If the estimated oxygen concentration C is within the specified range (step S340, Yes), the laser metal shaping apparatus 51A processes the base material 5 under processing conditions in which the estimated oxygen concentration C falls within the specified range (step S360).

[0123] After additive manufacturing of the base material 5 for a specific time period or after the additive manufacturing is completed, the laser metal sintering apparatus 51A estimates the oxygen concentration C and determines whether the estimated oxygen concentration C during processing is within a specified range (step S370). The laser metal sintering apparatus 51A here estimates the oxygen concentration C by the same process as steps S310 to S330 described above. The laser metal sintering apparatus 51A executes the process of step S370 after additive manufacturing for a specific time period during processing of the base material 5. The laser metal sintering apparatus 51A may execute the process of step S370 multiple times during processing of the base material 5.

[0124] If the estimated oxygen concentration C is not within the specified range (No at step S370), the flow rate of the shielding gas is adjusted, or the inside of the shielding gas nozzle 13 is inspected for foreign matter (step S350).

[0125] If the estimated oxygen concentration C is within the specified range (step S370, Yes), the laser metal sintering apparatus 51A continues processing the base material 5 (step S380). The laser metal sintering apparatus 51A may execute the processes of steps S310 to S350 again after the additive manufacturing is completed. In addition, the laser metal sintering apparatus 51A may acquire back data 61 using the base material 5 used in the additive manufacturing as the marker base material 21.

[0126] Thus, in the second embodiment, the laser metal sintering apparatus 51B records the parameter set 62 including the processing conditions, the temperature fluctuation range ΔT, and the oxygen concentration C in the back data 61. This enables the laser metal sintering apparatus 51A to accurately estimate the oxygen concentration C at the irradiation position during irradiation with the processing laser light 1, based on the processing conditions, the temperature fluctuation range ΔT, and the back data 61 when processing the marker base material 21.

[0127] Embodiment 3 Next, the third embodiment will be described with reference to Figs. 16 to 19. In the third embodiment, back data 61 is generated for each shape of the marker base material 21. Below, the same contents as in the first and second embodiments will be omitted, and only the contents different from the first and second embodiments will be described. In the third embodiment, the laser metal sculpting apparatus 50A and the laser metal sculpting apparatus 50B are used. Note that the laser metal sculpting apparatus 51A may be used instead of the laser metal sculpting apparatus 50A. In this case, the laser metal sculpting apparatus 51B is used instead of the laser metal sculpting apparatus 50B.

[0128] The laser metal sintering apparatus 50B of the third embodiment generates back data 61 by changing the shape of the shaped object (marker base material 21) onto which the shielding gas 17 is sprayed. When performing a quality check, the laser metal sintering apparatus 50A estimates the oxygen concentration C by using the marker base material 21 having a shape similar to that of the base material 5.

[0129] The marker base material 21 used by the laser metal sintering apparatus 50B when generating the back data 61 includes a marker base material 21 having a shape similar to the shape of the base material 5 that the laser metal sintering apparatus 50A processes in step S170 of Fig. 7. The laser metal sintering apparatus 50A then performs processing in step S110 of Fig. 7 on the marker base material 21 having a shape similar to the shape of the base material 5 that is processed in step S170 of Fig. 7.

[0130] Here, the relationship between the shape of the marker base material 21 and the oxygen concentration C will be described. Fig. 16 is a diagram showing the YZ cross-sectional shape of the marker base material having a first shape, and Fig. 17 is a diagram showing the XZ cross-sectional shape of the marker base material having the first shape. Fig. 18 is a diagram showing the YZ cross-sectional shape of the marker base material having a second shape, and Fig. 19 is a diagram showing the XZ cross-sectional shape of the marker base material having the second shape.

[0131] 16 and 17, the marker base material having the first shape is illustrated as marker base material 21A, while in Figures 18 and 19, the marker base material having the second shape is illustrated as marker base material 21B.

[0132] 16 and 17, the marker base material 21A has a convex YZ cross section. The laser metal printing devices 50A and 50B perform processing on the marker base material 21A having such a shape by blowing the shielding gas 17 while moving the processing head 8 in a direction parallel to the X-axis direction, thereby forming an empty bead 24.

[0133] 18 and 19, the marker base material 21B has a plate-like shape. The laser metal forming devices 50A and 50B perform processing on the marker base material 21B having such a shape by blowing the shielding gas 17 while moving the processing head 8 in a direction parallel to the X-axis direction, thereby forming an empty bead 24.

[0134] When performing additive manufacturing in a direction parallel to the X-axis direction on a marker base material 21A having a convex YZ cross section, the laser metal manufacturing apparatuses 50A and 50B irradiate a shielding gas 17 to the irradiation position of the processing laser beam 1. After passing through the irradiation position of the processing laser beam 1, the shielding gas 17 flows along the -Z-axis direction and does not flow in a direction parallel to the XY plane. That is, the shielding gas 17 flows from the top surface of the convex portion of the marker base material 21A along the side surface of the convex portion.

[0135] On the other hand, when the laser metal fabrication apparatuses 50A, 50B perform additive manufacturing on the plate-shaped marker base material 21B in a direction parallel to the X-axis direction, the shielding gas 17 passes through the irradiation position of the processing laser beam 1 and flows along a direction parallel to the XY plane on the upper surface of the marker base material 21B. As a result, a portion of the shielding gas 17 remains on the upper surface of the marker base material 21B, lowering the oxygen concentration C on the upper surface of the marker base material 21B. In other words, the oxygen concentration C is lower in the plate-shaped marker base material 21B than in the marker base material 21A, whose YZ cross section has a convex shape.

[0136] In this way, the oxygen concentration C in the processing region 4 changes depending on the different shapes of the marker base materials 21A, 21B onto which the shield gas 17 is sprayed. In the third embodiment, the laser metal sintering apparatus 50B generates back data 61 using marker base materials 21 having various shapes, thereby making it possible to evaluate the performance of the shield gas nozzle 13 for each shape of the marker base material 21. Furthermore, the laser metal sintering apparatus 50A can estimate the oxygen concentration C according to the shape of the base material 5 by estimating the oxygen concentration C based on the surface roughness R when processing is performed on a marker base material 21 having the same shape as the base material 5.

[0137] When the laser metal sintering devices 51A and 51B are used, the laser metal sintering device 51B generates back data 61 using marker base materials 21 having various shapes, thereby making it possible to evaluate the performance of the shield gas nozzle 13 for each shape of the marker base material 21. In addition, the laser metal sintering device 51A can estimate the oxygen concentration C according to the shape of the base material 5 by estimating the oxygen concentration C based on the temperature fluctuation width ΔT when processing is performed on a marker base material 21 having the same shape as the base material 5.

[0138] As described above, according to the third embodiment, the laser metal shaping apparatuses 50A and 50B estimate the oxygen concentration C for the marker base materials 21 having various shapes, and therefore can estimate the oxygen concentration C according to the shape of the base material 5.

[0139] Embodiment 4 Next, the fourth embodiment will be described with reference to Figs. 20 to 23. In the fourth embodiment, back data 61 is generated using a marker base material 21 on which a plurality of types of materials are arranged. In the following, the same contents as those in the first to third embodiments will be omitted, and only the contents different from the first to third embodiments will be described. In the fourth embodiment, the laser metal sculpting apparatus 50A and the laser metal sculpting apparatus 50B are used. Note that the laser metal sculpting apparatus 51A may be used instead of the laser metal sculpting apparatus 50A. In this case, the laser metal sculpting apparatus 51B is used instead of the laser metal sculpting apparatus 50B.

[0140] Fig. 20 is a top view of the marker base material according to the fourth embodiment in which multiple types of materials are arranged, and Fig. 21 is a diagram showing the shape of an XZ cross section of the marker base material according to the fourth embodiment in which multiple types of materials are arranged. In Figs. 20 and 21, the marker base material in which multiple different materials are arranged is illustrated as marker base material 21C. Marker base material 21C is a base material in which hollow beads 24 are formed by laser metal shaping apparatuses 50A and 50B.

[0141] In the marker base material 21C, for example, various materials are arranged along a direction parallel to the X-axis direction. The laser metal shaping devices 50A, 50B form the hollow bead 24 on the marker base material 21C while moving the processing head 8 along a direction parallel to the X-axis direction. In this way, the laser metal shaping devices 50A, 50B can form the hollow bead 24 for various materials in a short time.

[0142] Furthermore, when forming empty beads 24 for a plurality of types of materials, the laser metal sintering apparatuses 50A and 50B can reduce the time required for preparation for replacing the marker base material 21. Therefore, the laser metal sintering apparatus 50B can reduce the time required for generating the back data 61.

[0143] The region where the oxygen concentration C and surface roughness R change suddenly varies depending on the material from which the empty bead 24 is formed. For this reason, by using a marker base material 21C in which a plurality of different materials are arranged, it is possible to widen the measurable range of the oxygen concentration C. That is, since the reaction region 72 shown in FIG. 6 varies depending on the type of material of the marker base material 21C, it is possible to widen the measurable range of the oxygen concentration C by using marker base materials 21C with different reaction regions 72 in combination.

[0144] The composition of the marker base material 21 may be changed continuously. Fig. 22 is a top view of the marker base material according to the fourth embodiment in which the composition is changed continuously, and Fig. 23 is a diagram showing the shape of the XZ cross section of the marker base material according to the fourth embodiment in which the composition is changed continuously. In Figs. 22 and 23, the marker base material in which the composition is changed continuously is illustrated as marker base material 21D.

[0145] The marker base material 21D is made of, for example, a functionally gradient material that is a mixture of a metal that is easily oxidized and a material that is not easily oxidized. That is, the marker base material 21D is configured such that the composition ratio of the metal that is easily oxidized and the material that is not easily oxidized changes continuously along a direction parallel to the X-axis direction. For example, the composition ratio of the metal that is easily oxidized increases toward the +X-axis direction of the marker base material 21D, and the composition ratio of the material that is not easily oxidized decreases. With this configuration, the reaction regions 72, 76 of the marker base material 21D can be changed continuously. Therefore, the laser metal shaping apparatus 50B can generate the back data 61 using one functionally gradient material marker base material 21D from a region with a low oxygen concentration C (for example, 100 PPM or less) to a region with a high oxygen concentration C (for example, 2000 PPM or more). Furthermore, the laser metal shaping apparatus 50A can estimate the oxygen concentration C from a low oxygen concentration C region (eg, 100 PPM or less) to a high oxygen concentration C region (eg, 2000 PPM or more) using one functionally gradient material marker base material 21D.

[0146] As described above, according to the fourth embodiment, the laser metal sintering apparatuses 50A and 50B use the marker base material 21D on which multiple types of materials are arranged, and therefore can form the empty bead 24 for multiple types of materials in a short time. Furthermore, the laser metal sintering apparatus 50B can reduce the time required to generate the back data 61.

[0147] Here, the hardware configuration of the control device 12 will be described. The control device 12 is realized by a processing circuit. The processing circuit may be a processor and memory that executes a program stored in a memory, or may be dedicated hardware such as a dedicated circuit. The processing circuit is also called a control circuit.

[0148] FIG. 24 is a diagram showing a configuration example of a processing circuit when the processing circuit included in the control device according to the first to fourth embodiments is realized by a processor and a memory. The processing circuit 90 shown in FIG. 24 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is configured with the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. That is, the processing circuit 90 includes a memory 92 for storing a program that results in the processing of the control device 12 being executed. This program can also be said to be a program for causing the control device 12 to execute each function realized by the processing circuit 90. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium. The above program can also be said to be a program for causing the control device 12 to execute the control process.

[0149] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. Also, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc), etc.

[0150] FIG. 25 is a diagram showing an example of a processing circuit provided in the control device according to the first to fourth embodiments, configured with dedicated hardware. The processing circuit 93 shown in FIG. 25 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. The processing circuit 93 may be partially realized with dedicated hardware and partially realized with software or firmware. In this way, the processing circuit 93 can realize each of the above-mentioned functions by dedicated hardware, software, firmware, or a combination of these.

[0151] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0152] 1 Laser beam for processing, 2 Wire, 3 Bead, 4 Processing area, 5 Base material, 6 Stage, 7 Wire supply device, 8 Processing head, 9 Shielding gas supply device, 10 Laser oscillator, 11 Driving device, 12 Control device, 13 Shielding gas nozzle, 14 Laser head, 15 Height measuring device, 16A, 16B Gas piping, 17 Shielding gas, 18 Light transmission path, 19 Measurement laser beam, 20 Chamber, 21, 21A to 21D Marker base material, 22 Gas intake tube, 23 Oxygen concentration meter, 24 Empty bead, 25 Radiation thermometer, 50A, 50B, 51A, 51B Laser metal forming device, 60 Storage device, 61 Back data, 62 Parameter set, 71, 75 Insensitive area, 72, 76 Reaction area, 73, 77 Saturation area, 74 Starting period, 81 to 83 Correspondence, 90,93 Processing circuit, 91 Processor, 92 Memory.

Claims

1. a first transfer step in which a first base material including a metal is transferred to a first stage in a chamber of a first laser metal shaping apparatus; a first gas supplying step in which a first shielding gas supplying device of the first laser metal shaping apparatus supplies a first shielding gas into the chamber to prevent oxidation of the heated and melted metal; a first bead forming step in which a first processing head of the first laser metal shaping device irradiates a laser beam onto the first base material to heat and melt the first base material, thereby forming a first bead on the first base material; a concentration measuring step in which an oxygen concentration meter included in the first laser metal shaping apparatus measures an oxygen concentration in the chamber; a first characteristic measuring step in which a first measuring device included in the first laser metal shaping apparatus measures a first bead characteristic that is a characteristic of the first bead; a background data generating step in which a first control device of the first laser metal shaping apparatus generates background data in which the oxygen concentration is associated with the first bead feature; a second conveying step in which a second base material made of the same material as the first base material is conveyed to a second stage of a second laser metal shaping apparatus, the second stage being disposed in an open-to-air environment; a second gas supplying step in which a second shielding gas supplying device of the second laser metal shaping apparatus supplies the first shielding gas to the second base material; a second bead forming step in which a second processing head of the second laser metal shaping device irradiates the second base material with a laser beam to heat and melt the second base material, thereby forming a second bead on the second base material; a second characteristic measuring step in which a second measuring device included in the second laser metal shaping apparatus measures a second bead characteristic that is a characteristic of the second bead; an estimation step in which a second control device of the second laser metal shaping device estimates an oxygen concentration when the second base material is processed based on the back data and the second bead characteristics; Including, 4. An oxygen concentration estimation method comprising:

2. the first measuring device is a first height measuring device that measures a height of the first bead, the second measuring device is a second height measuring device that measures a height of the second bead, the first bead characteristic is a surface roughness of the first bead calculated based on a height of the first bead; The second bead characteristic is a surface roughness of the second bead, the surface roughness being calculated based on a height of the second bead.

2. The method for estimating oxygen concentration according to claim 1 .

3. the first measuring device is a first thermometer that measures a first temperature in a first processing region of the first base material when the first bead is formed; the second measuring device is a second thermometer that measures a second temperature in a second processing region of the second base material when the second bead is formed; the first bead characteristic is a temperature fluctuation range in the first processing region when the first bead is formed, the temperature fluctuation range being calculated based on the first temperature; The second bead characteristic is a temperature fluctuation range in the second processing region when the second bead is formed, the temperature fluctuation range being calculated based on the second temperature.

2. The method for estimating oxygen concentration according to claim 1 .

4. In the background data generating step, the first control device generates the background data in which the processing conditions used in forming the first bead, the oxygen concentration, and the first bead characteristics are associated with each other, The processing conditions include a laser output of the laser light irradiated to the first base material, an irradiation diameter of the laser light irradiated to the first base material, and a moving speed of the first processing head.

4. The method for estimating oxygen concentration according to claim 1, wherein the oxygen concentration is estimated by the measurement of the oxygen concentration.

5. In the back data generating step, the first control device generates the back data for each shape of the first base material.

5. The method for estimating oxygen concentration according to claim 1, wherein the oxygen concentration is estimated by the step of:

6. The first base material and the second base material are composed of members whose composition ratios change continuously in a specific direction.

5. The method for estimating oxygen concentration according to claim 1, wherein the oxygen concentration is estimated by the step of:

7. A first laser metal shaping device and a second laser metal shaping device are provided, The first laser metal shaping apparatus comprises: a first stage disposed in the chamber and carrying a first base material including a metal; a first shielding gas supply device that supplies a first shielding gas into the chamber to prevent oxidation of the heated and melted metal; a first processing head that irradiates a laser beam onto the first base material to heat and melt the first base material and form a first bead on the first base material; an oxygen concentration meter for measuring an oxygen concentration in the chamber; a first measurement device for measuring a first bead characteristic that is a characteristic of the first bead; A first control device that generates background data in which the oxygen concentration is associated with the first bead characteristic; having The second laser metal shaping apparatus comprises: a second stage that is placed in an open-to-air environment and to which a second base material made of the same material as the first base material is transported; a second shielding gas supply device that supplies the first shielding gas to the second base material; a second processing head that irradiates the second base material with a laser beam to heat and melt the second base material and form a second bead on the second base material; a second measurement device for measuring a second bead characteristic that is a characteristic of the second bead; A second control device that estimates an oxygen concentration when the second base metal is processed based on the back data and the second bead characteristics; having A molding system characterized by:

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