Lamination molding device

Abstract

To provide a lamination molding device that can stabilize a distance between a welding torch and a laminate.SOLUTION: A lamination molding device for molding a laminate by laminating a weld bead while moving a welding torch using a predetermined transport mechanism includes: a measuring device for measuring a position of an uppermost lamination of a laminate; and a control device for controlling the transport mechanism by correcting a distance between a welding torch and the uppermost lamination on the basis of a measurement value of the measuring device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an additive manufacturing apparatus. [Background technology]

[0002] Technologies for manufacturing by layering metals by arc welding (additive manufacturing methods) are disclosed, for example, in Patent Documents 1 and 2. These additive manufacturing methods stack beads of molten metal (weld beads) by moving a welding torch along a preset layering path, thereby manufacturing (forming) a specified layered object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-144446 A [Patent Document 2] Patent No. 6797324 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the height of the weld bead that is actually stacked tends to gradually decrease due to the accumulation of heat input to the stack. That is, the height of the weld bead of the next layer becomes lower relative to the height of the weld bead of the first layer. As a result, the distance between the welding torch and the stack gradually increases as the number of stacks increases, and ultimately, there is a problem that further stacking becomes difficult.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide an additive manufacturing device that is capable of stabilizing the distance between a welding torch and an accumulated workpiece. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention employs, as a first solution relating to an additive manufacturing apparatus, a means for forming a laminate by stacking weld beads while moving a welding torch using a predetermined transport mechanism, the apparatus comprising a measuring device that measures the position of the top layer of the laminate, and a control device that controls the transport mechanism by correcting the distance between the welding torch and the top layer based on the measurement value of the measuring device.

[0007] In the present invention, as a second solution related to an additive manufacturing apparatus, in the above-mentioned first solution, a means is adopted in which the measuring device measures the positions of multiple points of any layer in the laminate, and corrects the distance based on values ​​obtained by performing statistical processing on the measurement values ​​at the multiple points.

[0008] The present invention employs, as a third solution relating to the additive manufacturing apparatus, a solution in which a light shielding plate is provided between the welding torch and the measuring device in the above-mentioned first or second solution.

[0009] The present invention employs, as a fourth solution related to the layered manufacturing apparatus, the third solution described above, wherein the light shielding plate is movable forward and backward relative to the layered object.

[0010] The present invention employs a fifth solution relating to an additive manufacturing apparatus in which any of the first to fourth solutions described above is further provided with a welding fume removal device that removes welding fumes adhering to the measuring device.

[0011] The present invention provides a sixth solution related to an additive manufacturing apparatus according to the fifth solution, in which the welding fume removal device is provided separately for the light-projecting unit and the light-receiving unit of the measuring instrument. Effect of the Invention

[0012] According to the present invention, it is possible to provide an additive manufacturing apparatus capable of stabilizing the distance between a welding torch and a laminated object. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a configuration of an additive manufacturing apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a schematic diagram showing a configuration of a main part of an additive manufacturing apparatus according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a schematic diagram showing measurement points in an additive manufacturing apparatus according to an embodiment of the present invention. [Figure 4] 11A to 11C are schematic diagrams showing a correction operation of the layered manufacturing apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the additive manufacturing apparatus A according to this embodiment includes a welding torch 1, a transfer mechanism 2, a profile measuring device 3, a compressor 4, an electromagnetic valve 5, and a control device 6.

[0015] The welding torch 1 is an arc welding torch that melts a specified filler metal (metal) by arc discharge. Although not shown, this welding torch 1 is additionally provided with a filler metal delivery device that delivers the filler metal to the tip (arc discharge part). The welding torch 1 is moved in a predetermined direction along the surface of the base material b by the transport mechanism 2, and the filler metal delivered to the tip by the filler metal delivery device is melted and adhered to the surface of the base material b.

[0016] The transfer mechanism 2 is a mechanical element that moves the welding torch 1 based on a transfer command input from the control device 6. That is, the transfer mechanism 2 sequentially moves the welding torch 1 in a predetermined direction along the surface of the base material b based on the transfer command. Such a transfer mechanism 2 is, for example, an articulated robot (manipulator). The transfer mechanism 2 and the welding torch 1 cooperate to mold (form) a laminate W on the surface of the base material b.

[0017] The laminate W shown in Fig. 1 is in the process of being shaped (formed), and is made up of a first laminate y1, a second laminate y2, and a third laminate y3 formed on a base plate b. That is, the first laminate y1 is a weld bead formed directly on the surface of the base plate b. The second laminate y2 is a weld bead formed on the first laminate y1. Moreover, the third laminate y3 is a weld bead formed on the second laminate y2, and is the uppermost laminate in the present invention.

[0018] The profile measuring device 3 is a measuring device that measures the position of the top layer of the laminate W. The profile measuring device 3 is provided integrally with the welding torch 1 on the rear side in the movement direction of the welding torch 1. The profile measuring device 3 obtains measurement values ​​of the top layer of the laminate W at predetermined time intervals in accordance with the movement of the welding torch 1, and outputs the measurement values ​​to the control device 6 in sequence.

[0019] For example, when the movement trajectory of the welding torch 1 is annular and the surface of the base material b is horizontal as shown in Fig. 2, the profile measuring device 3 measures the distance to the top layer. This height position is measured at multiple points at predetermined intervals on the movement trajectory of the welding torch 1 in the movement direction as shown in Fig. 2.

[0020] 1, such a profile measuring instrument 3 is provided with a light projecting unit 3a, a light receiving unit 3b, a light shielding plate 3c, a first gas injection hole 3d, and a second gas injection hole 3e. The light projecting unit 3a is a light emitting element that projects measurement light p of a predetermined wavelength onto the surface of the third stack y3 (top stack). This measurement light p is reflected by the surface of the third stack y3 (top stack) as shown in the figure, and enters the light receiving unit 3b.

[0021] The light receiving unit 3b is a light receiving element that receives the measurement light p (reflected light) incident from the third stack y3 (top stack). That is, the light receiving unit 3b receives the measurement light p (optical signal) and converts it into a received light signal (electrical signal). The profile measuring device 3 measures the surface position of the third stack y3 (top stack) based on, for example, the difference (delay) between the timing of projecting the measurement light p at the light projecting unit 3a and the timing of receiving the measurement light p at the light receiving unit 3b.

[0022] As shown in the figure, the light shielding plate 3c is provided on the welding torch 1 side of the profile measuring instrument 3. That is, the light shielding plate 3c is provided between the profile measuring instrument 3 and the welding torch 1. This light shielding plate 3c is a plate- or sheet-shaped member that blocks or suppresses light accompanying the arc discharge generated at the tip of the welding torch 1 from entering the light receiving unit 3b as a disturbance.

[0023] The light shielding plate 3c is, for example, a relatively hard flat plate or a flexible sheet material made of a material that does not transmit light. As shown in the figure, the light shielding plate 3c is provided in a state where its tip (lower end) is in contact with the surface of the third layer y3 (top layer), or in a state where it is not in contact but the distance from the layer is sufficiently small. The width (horizontal width Ls) of the light shielding plate 3c in the direction perpendicular to the opposing direction of the welding torch 1 and the profile measuring instrument 3 is set to be several times the horizontal width Lb of the third layer y3 (top layer).

[0024] Furthermore, when the light shielding plate 3c is made of a light-shielding flat metal plate, it is attached to the profile measuring instrument 3 so as to be able to move forward and backward with respect to the surface (upper end) of the third stack y3 (top stack), as shown in Fig. 2. That is, the light shielding plate 3c can freely move forward and backward with respect to the stack W, and when the fourth stack y4 (top stack) is stacked on the third stack y3 as shown in Fig. 2, the light shielding plate 3c comes into contact with the surface (upper end) of the fourth stack y4 (top stack).

[0025] Such a light shielding plate 3c is pressed against the surface (upper end) of the third layer y3 (top layer) by a biasing member such as a spring. When the portion of the light shielding plate 3c that abuts against the surface (upper end) of the top layer is formed of a flexible sheet material, the material of the light shielding plate 3c may be, for example, a non-flammable woven fabric such as High Silica Fiber (trade name), Maftec (trade name), or Arsen (trademark).

[0026] The first gas injection hole 3d is an opening for injecting the first compressed gas a1 toward the light projection part 3a. The first compressed gas a1 is directly sprayed from the first gas injection hole 3d to the light projection part 3a. Such first compressed gas a1 effectively removes welding fumes that may adhere to the light projection part 3a.

[0027] The second gas injection hole 3e is an opening for injecting the second compressed gas a2 toward the light receiving surface of the light receiving part 3b. The second compressed gas a2 is directly sprayed from the second gas injection hole 3e to the light receiving part 3b. Such second compressed gas a2 effectively removes welding fumes that may adhere to the light receiving part 3b.

[0028] The compressor 4 is a gas supply source that supplies the first and second compressed gases a1 and a2 to the first and second gas injection holes 3d and 3e. As shown in the figure, the compressor 4 and the first and second gas injection holes 3d and 3e are connected to each other by a gas pipe 7 that allows the first and second compressed gases a1 and a2 to flow freely. For example, air or argon gas is used as the first and second compressed gases a1 and a2.

[0029] Of the first and second compressed gases a1 and a2 discharged from the compressor 4, the first compressed gas a1 is supplied to the first gas injection hole 3d via the gas piping 7, and the second compressed gas a2 is supplied to the second gas injection hole 3e via the gas piping 7. The operation of the compressor 4 is controlled by the control device 6.

[0030] The electromagnetic valve 5 is an opening / closing device provided in the gas piping 7, which sets the supply / cutoff of the first and second compressed gases a1, a2 to the first and second gas injection holes 3d, 3e. That is, the electromagnetic valve 5 sets the supply / cutoff of the first and second compressed gases a1, a2 to the first and second gas injection holes 3d, 3e based on an opening / closing signal input from the control device 6.

[0031] Here, the welding fume removal device of the present invention is composed of the electromagnetic valve 5, the first and second gas injection holes 3d, 3e, the compressor 4, and the gas piping 7. That is, the first and second gas injection holes 3d, 3e, the compressor 4, the electromagnetic valve 5, and the gas piping 7 have the function of removing welding fumes adhering to the profile measuring instrument 3 (measuring instrument), and are provided individually for the light projecting unit 3a and the light receiving unit 3b that the profile measuring instrument 3 (measuring instrument) has.

[0032] The control device 6 is a software control device that performs unified control of the additive manufacturing apparatus A. That is, the control device 6 performs unified control of the welding torch 1, the transfer mechanism 2, the profile measuring device 3, the compressor 4, and the electromagnetic valve 5 based on a control program stored in advance, thereby forming (modeling) the laminate W on the base material b.

[0033] Next, the operation of the layered manufacturing apparatus A according to this embodiment will be described in detail with reference to FIGS.

[0034] For example, when the movement trajectory of the welding torch 1 is annular as shown in FIG. 3, that is, when the laminate W is shaped (formed) by stacking annular weld beads on the surface of the base material b, the welding torch 1 and the profile measuring device 3 move along an annular movement route R on the surface of the base material b.

[0035] That is, the welding torch 1 and the profile measuring instrument 3 move sequentially from a preset stacking start point in the stacking direction along annular movement route R through cooperation between the transport mechanism 2 and the control device 6. Of the integrated welding torch 1 and profile measuring instrument 3, the welding torch 1 moves first, and the profile measuring instrument 3 is positioned behind the welding torch 1 and moves together with it.

[0036] Then, while the welding torch 1 and the profile measuring device 3 make one revolution along the annular movement route R, the welding torch 1 is operated to form an annular first layered layer y1 on the surface of the base material b. When the welding torch 1 starts to operate, the first and second compressed gases a1 and a2 are injected toward the first layered layer y1 from the first and second gas injection holes 3d and 3e.

[0037] Furthermore, the profile measuring instrument 3 sequentially measures the top surface position of the first layer y1 (top layer) for each measurement point while making one revolution along the annular movement route R, and outputs multiple measurement values ​​to the control device 6. The control device 6 performs predetermined statistical processing on the multiple measurement values ​​obtained from the profile measuring instrument 3 to calculate an average value over one revolution of the annular movement route R.

[0038] Then, the control device 6 uses the average value to correct the height position of the welding torch 1 (for example, the height position of the welding torch 1 based on the surface of the base material b) that is preset as a planned position when forming the second layered layer y2 on the first layered layer y1, and controls the transfer mechanism 2. As a result, the height position of the welding torch 1 when forming the second layered layer y2 corresponds to the actual height of the first layered layer y1.

[0039] For example, as shown in Fig. 4(a), the height position Lr of the welding torch 1 is set relative to the height (ideal height Hr) of the ideal layered layer yr that is planned in advance. In contrast, as shown in Fig. 4(b), if the height H1 of the first layered layer y1 actually formed on the base material b is higher than the ideal height Hr by Δr, that is, if the average value is calculated as (Hr+Δr), the height position L1 of the welding torch 1 is corrected to (Lr+Δr) based on this average value (Hr+Δr).

[0040] On the other hand, if the height H1 of the first layer y1 actually formed on the base material b is lower than the ideal height Hr by Δr, that is, if the above average value is calculated as (Hr-Δr), the height position L1 of the welding torch 1 is corrected to (Lr-Δr) based on this average value (Hr-Δr). In other words, the height position L1 of the welding torch 1 is optimized with respect to the height H1 of the first layer y1 actually formed on the surface of the base material b.

[0041] Here, the above statistical processing will be further explained. The profile measuring instrument 3 acquires measurement values ​​at multiple measurement points while making one revolution along the circular movement route R. The control device 6 excludes from these multiple measurement values ​​those measurement values ​​that are extremely different from the other measurement values ​​from the measurement values ​​used to calculate the average value.

[0042] 3, for example, white circles indicate measurement values ​​excluded from the measurement values ​​used to calculate the average value, and black circles indicate measurement values ​​used to calculate the average value. In this example, the average value is ultimately calculated from five measurement values ​​out of the multiple measurement points acquired by the profile measuring instrument 3 over one revolution of the circular movement route R.

[0043] When the welding torch 1 starts to operate, an arc discharge occurs between the tip of the welding torch 1 and the base material b. That is, when the first laminated layer y1 is formed on the base material b, light resulting from the arc discharge (arc light) is constantly generated.

[0044] However, since a light shielding plate 3c is provided on the welding torch 1 side of the profile measuring instrument 3, it is possible to prevent or suppress the arc light from entering the light receiving part 3b of the profile measuring instrument 3. Therefore, it is possible to prevent the arc light generated by the welding torch 1 from acting as a disturbance to the measurement in the profile measuring instrument 3.

[0045] Furthermore, when the welding torch 1 starts to operate, welding fumes are generated between the tip of the welding torch 1 and the base material b. These welding fumes may bypass the light shielding plate 3c and enter the profile measuring instrument 3 side, and may adhere to the light projecting part 3a and the light receiving part 3b.

[0046] However, when the welding torch 1 is operated, the first and second compressed gases a1, a2 are sprayed from the first and second gas injection holes 3d, 3e toward the light projecting part 3a and the light receiving part 3b, so that the welding fumes adhering to the light projecting part 3a and the light receiving part 3b are effectively removed by the first and second compressed gases a1, a2.

[0047] According to this embodiment, the additive manufacturing apparatus A forms a laminate W by stacking first to third layers y1 to y3 (weld beads) while moving a welding torch 1 using a predetermined transport mechanism 2, and is equipped with a profile measuring device 3 (measuring device) that measures the position of the top layer of the laminate W, and a control device that controls the transport mechanism 2 by correcting the distance between the welding torch 1 and the top layer based on the measurement value of the profile measuring device 3 (measuring device), so that it is possible to stabilize the distance between the welding torch 1 and the laminate W.

[0048] Furthermore, according to this embodiment, the profile measuring instrument 3 (measuring instrument) measures the positions of multiple locations of any layer in the laminate W, and corrects the distance between the welding torch 1 and the top layer based on values ​​obtained by performing statistical processing on the measured values ​​at the multiple locations, thereby making it possible to further stabilize the distance between the welding torch 1 and the laminate W.

[0049] Furthermore, according to this embodiment, a light shielding plate 3c is provided between the welding torch 1 and the profile measuring instrument 3 (measuring instrument), so that it is possible to prevent the arc light of the welding torch 1 from acting as a disturbance on the profile measuring instrument 3, thereby improving the reliability of the measurement values ​​of the profile measuring instrument 3.

[0050] Furthermore, according to this embodiment, the light shielding plate 3c can be freely advanced and retreated relative to the stack W, so that even if the total number of stacks W changes, it is possible to prevent the arc light of the welding torch 1 from acting as a disturbance on the profile measuring instrument 3, thereby improving the reliability of the measurement values ​​of the profile measuring instrument 3 (measuring instrument).

[0051] Furthermore, according to this embodiment, a welding fume removal device that removes welding fumes adhering to the profile measuring instrument 3 (measuring instrument) is further provided, so it is possible to prevent or suppress a decrease in the measurement accuracy of the profile measuring instrument 3 (measuring instrument) caused by welding fumes. This also makes it possible to improve the reliability of the measurements of the profile measuring instrument 3 (measuring instrument).

[0052] Furthermore, according to this embodiment, the welding fume removal device is provided separately for the light projecting unit 3a and the light receiving unit 3b of the profile measuring instrument 3 (measuring instrument), so it is possible to stabilize the projection of the measurement light p by the light projecting unit 3a onto the laminate W, and also to stabilize the reception of the measurement light p (reflected light) by the light receiving unit 3b. This also makes it possible to improve the reliability of the measurement values ​​of the profile measuring instrument 3 (measuring instrument).

[0053] In the above embodiment, the welding fume removal device is provided for the light projecting unit 3a and the light receiving unit 3b, but the present invention is not limited to this. That is, the welding fume removal device may be provided for either the light projecting unit 3a or the light receiving unit 3b as necessary. For example, it is conceivable to provide the welding fume removal device only for the light projecting unit 3a, which is closer to the welding torch 1.

[0054] In the above embodiment, the light shielding plate 3c is provided to shield one surface of the profile measuring instrument 3 (measuring instrument), but the present invention is not limited to this. Arc light caused by arc discharge can be reflected by surrounding members such as the base plate b and enter the light receiving unit 3b from all directions, so the light shielding plate 3c may be provided to shield not only one surface of the profile measuring instrument 3 (measuring instrument), but multiple surfaces of the profile measuring instrument 3 (measuring instrument). [Explanation of symbols]

[0055] A Additive Manufacturing Equipment W laminate a1, a2 compressed gas b Base plate p measurement light y1 1st layer (welded beam) y2 2nd layer (welded beam) y3 3rd layer (welded beam) y4 4th layer (welded beam) 1. Welding torch 2 Transfer mechanism 3. Profile measuring instrument (measuring instrument) 3a Light projector 3b Light receiving part 3c light shielding plate 3d First gas nozzle (welding fume removal device) 3e Second gas injection hole (welding fume removal device) 4 Compressor (welding fume removal device) 5. Solenoid valve (welding fume removal device) 6. Control device 7 Gas piping (welding fume removal device)

Claims

1. An additive manufacturing apparatus that manufactures a laminated object by stacking weld beads while moving a welding torch using a predetermined transport mechanism, a measuring device for measuring the position of the top layer of the stack; a control device that corrects the distance between the welding torch and the top layer based on the measurement value of the measuring device and controls the transfer mechanism; An additive manufacturing apparatus comprising:

2. The additive manufacturing apparatus according to claim 1 , wherein the measuring device measures the positions of a plurality of points of an arbitrary layer in the laminate, and corrects the distance based on values ​​obtained by performing statistical processing on the measured values ​​at the plurality of points.

3. The additive manufacturing apparatus according to claim 1 or 2, further comprising a light shielding plate between the welding torch and the measuring device.

4. The layered manufacturing apparatus according to claim 3 , wherein the light shielding plate is movable forward and backward relative to the stack.

5. The additive manufacturing apparatus according to claim 3 , further comprising a welding fume removal device for removing welding fumes adhering to the measuring device.

6. The additive manufacturing apparatus according to claim 5 , wherein the welding fume removal device is provided individually for a light projecting unit and a light receiving unit of the measuring instrument.

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