JP2015160217A - Three-dimensional molding device, three-dimensional molding article, and control program for three-dimensional molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent not only a large error from occurring in height directions as the whole molding article, but also a three-dimensional molding article itself from collapsing when beads of upper layers to be stacked on beads of lower layers are to be stacked in an oblique direction.SOLUTION: A three-dimensional molding device is provided which comprises a weld torch that feeds droplets of a metal wire melted by arc discharge in the direction of an opposite substrate, a movement mechanism that relatively moves the substrate and the weld torch, an arithmetic part that calculates a parameter value that controls a droplet amount of fed droplet on the basis of a displacement from the center line, and a control part that controls the weld torch and the movement mechanism on the basis of the parameter value calculated by the arithmetic part.

Description

  The present invention relates to a three-dimensional modeling apparatus, a three-dimensional modeled modeling method, and a control program for a three-dimensional manufacturing apparatus.

A three-dimensional modeling apparatus that forms a three-dimensional model by laminating weld beads formed by melting a metal welding wire is known.
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Unexamined Patent Publication No. 2000-15363

  When stacking the upper layer beads to the lower layer bead in an oblique direction, the upper layer bead does not reach the target height mainly due to the drooping in the gravity direction, and the stacking process is repeated as it is, In addition to causing a large error in the height direction of the entire model, the three-dimensional shape itself sometimes collapsed.

  The three-dimensional modeling apparatus according to the first aspect of the present invention includes a welding torch for sending a molten metal melted by arc discharge in the direction of the opposing substrate, and a moving mechanism for relatively moving the substrate and the welding torch. And the amount of droplets to be delivered when the second weld bead is formed by being displaced from the center line in the extending direction of the first weld bead on the first weld bead formed by the droplets. A calculation unit that calculates a parameter value for controlling the value based on the amount of deviation from the center line, and a control unit that controls the welding torch and the moving mechanism based on the parameter value calculated by the calculation unit.

  The three-dimensional modeling apparatus according to the second aspect of the present invention includes a welding torch for sending a droplet in which a metal wire is melted by arc discharge in the direction of the opposing substrate, and a moving mechanism for relatively moving the substrate and the torch. A measurement unit for measuring the shape of the first weld bead formed by the droplets and a first weld bead formed by laminating the second weld bead by deviating from the center line in the extending direction of the first weld bead A calculation unit that calculates a parameter value for controlling the droplet amount of the droplet to be sent based on the deviation from the center line and the measurement result of the measurement unit, and based on the parameter value calculated by the calculation unit And a control unit for controlling the welding torch and the moving mechanism.

  In the method for modeling a three-dimensional structure according to the third aspect of the present invention, a first weld bead is formed on a first weld bead formed by feeding a droplet obtained by melting a metal wire by arc discharge in the direction of an opposing substrate. When the second weld bead is formed by being deviated from the center line in the extending direction, a parameter value for controlling the amount of droplet to be delivered is calculated based on the amount of deviation from the center line. And a control step for controlling a welding torch for sending droplets and a moving mechanism for relatively moving the substrate and the welding torch based on the parameter values calculated by the calculation step.

  In the method for modeling a three-dimensional structure according to the fourth aspect of the present invention, measurement is performed to measure the shape of the first weld bead formed by sending a molten metal melted by arc discharge in the direction of the opposing substrate. And a parameter value for controlling the amount of droplets to be delivered when the second weld bead is formed by laminating the first weld bead from the center line in the extending direction of the first weld bead. A calculation process based on the amount of deviation from the center line and the measurement result of the measurement process, a welding torch for sending droplets based on the parameter value calculated by the calculation process, and a substrate and a welding torch And a control step of controlling a moving mechanism that moves relatively.

  According to a fifth aspect of the present invention, there is provided a control program for a three-dimensional manufacturing apparatus, wherein a first weld bead is formed on a first weld bead formed by sending a molten metal wire melted by arc discharge in the direction of an opposing substrate. When the second weld bead is formed by being deviated from the center line in the extending direction, a parameter value for controlling the amount of droplet to be delivered is calculated based on the amount of deviation from the center line. Based on the calculation step and the parameter value calculated in the calculation step, the computer is caused to execute a welding torch for sending a droplet and a control step for controlling a moving mechanism for relatively moving the substrate and the welding torch.

  The control program for the three-dimensional manufacturing apparatus according to the sixth aspect of the present invention measures the shape of the first weld bead formed by sending a molten metal melted by arc discharge in the direction of the opposing substrate. Step and parameter values for controlling the amount of droplets to be delivered when the second weld bead is stacked on the first weld bead by deviating from the center line in the extending direction of the first weld bead A calculation step for calculating the deviation from the center line and the measurement result of the measurement step, a welding torch for sending droplets based on the parameter value calculated by the calculation step, and the substrate and the welding torch. And causing the computer to execute a control step of controlling the moving mechanism that moves relatively.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is a schematic diagram which shows the structure of the three-dimensional modeling apparatus which concerns on this embodiment. It is an expanded sectional view near the tip part of a welding torch. It is a schematic diagram which shows the example of a molded article. It is a figure which shows the relative positional relationship of the lower layer bead and laminated bead in a cross section. It is a flowchart which shows the formation process in 1st Example. It is a flowchart which shows the formation process in 2nd Example. It is a specification value related to the experiment. It is the experimental result which shape | molded aiming at the shape of FIG.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a schematic diagram illustrating a configuration of a three-dimensional modeling apparatus 100 according to the present embodiment. The three-dimensional modeling apparatus 100 is arranged on a base 110, a stage 120 supported by the base 110 and moving in the y-axis direction orthogonal to the z-axis that is the direction of gravity, and a position that does not hinder the movement of the stage 120, A support column 130 extending from the base 110 in the z-axis direction is provided. The support column 130 has a guide rack extending in the z-axis direction, and supports the movable arm 140 so as to be movable in the direction. The movable arm 140 has a guide rack extending in the x-axis direction, and supports the holder 150 so as to be movable in this direction. The movement of the stage 120 in the y-axis direction, the movement of the movable arm 140 in the z-axis direction, and the movement of the holder 150 in the x-axis direction are performed by actuators provided respectively. Driving of the moving mechanism including these actuators is executed by the control unit 400 via the drive unit 440.

  The holder 150 fixes the mounted welding torch 200 along the z-axis direction. A guide tube 160 is connected to one end side of the welding torch 200. The guide tube 160 supplies a metal welding wire 210 and a shield gas described later to the welding torch 200 through the space in the tube.

  The other end side of the welding torch 200 faces the substrate 510 placed on the stage 120. The substrate 510 is fixed by a chuck 310 provided on the stage 120. The welding wire 210 drawn from the other end side of the welding torch 200 is melted by arc discharge and delivered as a droplet to the opposing substrate 510 side. The droplets are stacked on the substrate 510 to form a target three-dimensional structure 520. Although specifically described later, the series of operations are executed by the control unit 400 via the discharge unit 420.

  An image sensor 220 made up of, for example, a CCD image sensor is attached to the outer periphery of the welding torch 200. The image sensor 220 captures the formed object 520 to be formed and sends image data to the image unit 430. The image unit 430 measures the three-dimensional shape of the modeled object 520 and delivers the measurement result to the control unit 400.

  In the drawing, a cooling tank 300 is placed on the stage 120, although it is indicated by a dotted line for explaining each structure. The cooling tank 300 is filled with cooling water, and the substrate 510, the modeled object 520, and the like are immersed in the cooling water.

  The control unit 400 controls the entire 3D modeling apparatus 100 in an integrated manner. The control unit 400 acquires CAD data from the external CAD system 700 via the acquisition unit 450. The storage unit 460 is, for example, a flash memory, and stores a control program for operating the 3D modeling apparatus 100, various parameter values, a lookup table to be described later, and the like. The control unit 400 appropriately reads and uses these from the storage unit 460. The control unit 400 includes a calculation unit 410. In other words, the control unit 400 also functions as the calculation unit 410. The calculation unit 410 performs a correction calculation for correcting a parameter value to be applied when forming the modeled object 520 along the CAD data, for example.

  Next, how the three-dimensional shaped object 520 that is the target is formed will be described. FIG. 2 is an enlarged cross-sectional view of the vicinity of the tip of the welding torch 200. The welding torch 200 has a cylindrical shape, and a power feeding portion 201 is disposed coaxially in an internal cylindrical space. Electric power is supplied to the welding wire 210 drawn into the welding torch 200 by sliding in contact with the power supply unit 201.

  Further, the shield gas 202 fed through the guide tube 160 passes through the cylindrical space of the welding torch 200 and is jetted from the end opening toward the substrate 510. The shield gas 202 is, for example, carbon dioxide, and plays a role of preventing the molten welding wire 210 such as the droplet 211 from coming into contact with air and preventing the droplet 211 from scattering.

  An arc discharge is generated between the welding wire 210 and the substrate 510 or the bead 521 that has already been formed by the power supply by the power supply unit 201, and the molten droplet 211 drops to form part of the bead 521.

  The entire welding torch 200 is moved in the z direction so that the welding wire 210 is fed in the z-axis minus direction (gravity direction) and the tip of the welding wire 210 is at an appropriate height between the drip target position. The substrate 510 follows the movement of the stage 120 in the y-axis direction. The figure shows a cross section of the bead 521 extending in the y-axis direction. When the stage 120 is moved in the y-axis direction in synchronization with the dropping of the droplet 211, the bead 521 is gradually extended in the y-axis direction. To do. On the other hand, when the holder 150 to which the welding torch 200 is attached is moved in the x-axis direction in synchronization with the dropping of the droplet 211, the bead 521 is gradually extended in the x-axis direction. If the movement of the stage 120 in the y-axis direction and the movement of the holder 150 in the x-axis direction are linked, the bead 521 can be extended in an oblique direction.

  When the beads 521 are stacked, a method of stacking one layer at a time and a method of stacking continuously in a one-stroke writing format are conceivable. When stacking one layer at a time, the beads of each layer are connected at the start and end points. In this case, when the lower layer bead reaches the end point, the dropping of the droplet 211 is temporarily stopped, the welding torch 200 is lifted, the starting point of the upper layer bead is determined, and the dropping of the droplet 211 is started again. When stacking continuously in a one-stroke format, the welding torch 200 is lifted and the beads are continuously distracted while the dropping of the droplet 211 is continued even when the lower layer bead reaches the end point. That is, the boundary part from the lower layer bead to the upper layer bead is continuously formed. According to the experiment results of the present applicant, according to the method of stacking one layer at a time, a step in the gravitational direction is likely to occur at the boundary between the start point and the end point, whereas according to the method of stacking continuously, the step is not easily generated and is smooth. It was found that the surface can be realized. Therefore, in the present embodiment, a method of continuously stacking a stack of beads in a one-stroke writing format is employed. However, depending on the three-dimensional shape to be formed, there may be cases where all of them are not continuously stacked in a single stroke format, for example, there are a plurality of cavities inside. In that case, once the dropping of the droplet 211 is stopped to complete the lower layer bead, the welding torch 200 may be moved to form a new bead from another starting point. In other words, if they are continuously stacked, they are stacked, and if not, they are stacked while discontinuous connection points are minimized. At this time, it is preferable to set discontinuous connection points in consideration of the symmetry of the three-dimensional shape to be formed.

  FIG. 3 is a schematic diagram illustrating an example of the modeled object 520. FIG. 3A is a perspective view, and FIG. 3B is a side view. According to the example of the figure, the modeled object 520 is an oblong cylinder with a part of the side surface formed by spirally stacking a single bead 521. In the vicinity of one end side of the long side surface, the side surface stands upright with respect to the surface of the substrate 510 as indicated by the first auxiliary line 901. And it inclines gradually toward the other end side from one end side, and inclines by (theta) with respect to the normal line of the surface of the board | substrate 510 as the 2nd auxiliary line 902 shows in the vicinity of the other end side.

  When the three-dimensional shaped object 520 having such an overhang is formed by laminating the beads 521, it is inclined by laminating the upper bead 521 while being displaced from the center line in the extending direction of the lower bead 521. Is realized. At this time, if the stacking process is executed without performing any correction control, the upper layer bead 521 to be stacked hangs down in the direction of gravity before solidification, and the target stacking height cannot be realized. Then, not only a large error occurs in the height direction as a whole of the modeled object 520, but also the inclination angle θ becomes large, and in some cases, the three-dimensional shape itself may collapse. Therefore, in the present embodiment, correction control is performed when the upper layer bead 521 is stacked while being displaced from the center line in the extending direction of the lower layer bead 521. The correction control will be specifically described below.

  FIG. 4 is a diagram illustrating a relative positional relationship between the lower layer bead 5211 and the stacked bead 5212 stacked as the upper layer bead in a cross section orthogonal to the extending direction of the lower layer bead 5211. In the lower layer bead 5211, the y-axis direction is the extending direction, and the laminated bead 5212 is stacked in the position slightly deviated from the lower layer bead 5211, although the extending direction is the y-axis direction. More specifically, the center line in the extension direction of the laminated beads 5212 is displaced by d in the x-axis direction with respect to the center line in the extension direction of the lower layer bead 5211. That is, the laminated bead 5212 is formed by dropping the droplet 211 along the illustrated dropping line, aiming at a position displaced by d in the x-axis direction from the center line of the lower layer bead 5211.

When the deviation amount d is determined in this way, the inclination angle of the laminated bead 5212 with respect to the lower layer bead 5211 in the xz plane is θ as shown in the figure. More precisely, in the cross section in the xz plane, an inclination formed by a vertical line passing through the center line of the lower layer bead 5211 and an inclination line connecting the center line and the apex of the target height of the laminated bead 5212. The angle is θ. When the target value of the height stacked by stacking the stacked beads 5212 is H,
tan θ = d / H (1)
Holds. Further, as shown in the figure, the height from the intersection of the dropping line and the lower layer bead 5211 to the apex of the lower layer bead 5211 is defined as e. Then the height to be stacked on the drip line is a function of θ,
H (θ) = H + e (2)
It is expressed. Here, the upper surface of the lower layer bead 5211 is a quadratic function C having an apex at the center line in the distraction direction in the cross section of the illustrated xz plane:
y = ax ² (where a is a coefficient) (3)
When approximated by
e = | aH ² tan ² θ | (4)
Holds. Therefore, substituting equation (4) into equation (2),
H (θ) = H + | aH ² tan ² θ | (5)
Get.

  In the above, the coefficient a is determined by the image unit 430 analyzing the image data obtained by photographing the lower layer bead 5211 by the image sensor 220 to identify the cross-sectional shape, and the calculation unit 410 fits a quadratic function to the result. Is calculated. Alternatively, the image unit 430 identifies the width of the lower layer bead 5211, and the control unit 400 determines the coefficient a by referring to a correlation function or a lookup table of the bead width and the coefficient a prepared in the storage unit 460 in advance. . When the image sensor 220 and the image unit 430 are not provided, the coefficient a may be determined from the parameters when the lower layer bead 5211 is formed without analyzing the shape of the lower layer bead 5211. For example, the relationship between the droplet amount of the droplet 211 dropped per unit length in the extending direction of the bead (y direction in the figure) and the coefficient a is experimentally acquired in advance, and a lookup table is created and stored. Stored in the unit 460. The control unit 400 determines the coefficient a by applying the droplet amount when the lower layer bead 5211 is formed to the lookup table stored in the storage unit 460. The parameter of interest is not limited to the droplet amount of the droplet 211 dropped per unit length, and various parameter values that can be changed may be used as input values. For example, a lookup table in which the coefficient a is correlated with two or more parameters such as the feed speed of the welding torch 200 in the xy direction and the applied voltage of the power feeding unit 201 may be created. In this case, the coefficient a can be determined by applying the feed speed in the xy direction of the welding torch 200 when the lower layer bead 5211 is formed, the applied voltage of the power supply unit 201, and the like to the lookup table.

When the dropping amount of the droplet 211 delivered per unit time is constant, the height H _{0 of the} bead formed on the flat plate substrate is related to the feed rate F of the welding torch 200 with respect to the flat plate substrate as follows. It was confirmed experimentally.
H ₀ = kF ^m (where k and m are constants) (6)
For example, k = 35.568 and m = −0.57 were obtained as experimental results for F (mm / min) with respect to H (mm).

Also,
H ₀ ≈H (θ) (7)
It was found that the experimental results were good when using the approximate expression. Therefore, when expanding by substituting the equations (5) and (6) into the equation (7),
F = [{H + | aH ² tan ² θ |} / k] ^{(1 / m)} (8)
The correction formula can be derived.

In the present embodiment, the feed rate of the welding torch 200 is corrected using the correction formula (8). Specifically, regarding Equation (6), k, F, and m are previously experimentally identified for various values of H ₀ , and values of these combinations are stored in the storage unit 460 as a lookup table. Let me. When the modeling object 520 is modeled, if the inclination angle θ is determined from the displacement amount d of the laminated bead 5212 (the inclination angle θ may be determined first from CAD data), H (θ) is determined. 7) The lookup table in the storage unit 460 is referred to using the relationship of the formula. When the corresponding k, F, and m are determined from the look-up table, the feed speed F that is actually driven is determined by equation (8).

  In the above description, the drop amount of the droplet 211 delivered per unit time is constant, but the droplet amount delivered may be a variable parameter. When the droplet amount is a variable parameter, at least one of the supply speed of the welding wire 210, the voltage value of the supply power, the current value, and the like related thereto may be changed. In this case, k, F, and m for each of these variable parameters may be experimentally identified in advance. If such a look-up table is prepared in advance, even during modeling of the modeled object 520, it is possible to perform flexible correction control such as deriving the feed rate F when the amount of droplets to be sent out is changed. .

  The formation process of the molded article 520 to which the above correction control is applied will be described. FIG. 5 is a flowchart showing the forming process in the first embodiment. A series of flows starts when the setup is completed such that the substrate 510 is fixed to the stage 120 and the cooling bath 300 is filled with cooling water.

  In step S101, the control unit 400 acquires CAD data from the CAD system 700 via the acquisition unit 450. The control unit 400 generates path data for accumulating beads in a one-stroke writing format from the acquired CAD data. The generated path data includes information on the amount of deviation of the stacked bead relative to the lower layer bead, information on the target height of each layer, and the like.

  The control unit 400 proceeds to step S102, and determines whether or not the target position of the stacked bead to be formed by sending the droplet 211 is directly above the lower layer bead from the generated path data. In addition, when forming the lowermost bead directly formed on the substrate 510, it is determined to be directly above the lower bead. “Directly above” refers to a case where stacked beads are stacked vertically on the substrate 510. Therefore, the control unit 400 determines YES when stacking in the vertical direction, and determines NO when stacking in a tilted manner.

  If NO is determined in step S102, the control unit 400 proceeds to step S103, and identifies the deviation amount from the generated path data. In step S104, the control unit 400 receives the cross-sectional shape of the lower layer bead measured by the image unit 430. In step S105, a quadratic function is applied to the acquired cross-sectional shape to determine the coefficient a.

  In step S106, the control unit 400 calculates the above-described H (θ) from the target height information included in the path data, and stores the above-described k, F, and m corresponding to the H (θ). This is determined with reference to the lookup table stored in the table. In step S107, calculation unit 410 determines the value of feed speed F of welding torch 200 as a control parameter using these determined control values. Of course, as described above, the control values of the control parameters other than the feed speed F of the welding torch 200 may be changed.

  When the control value of the control parameter is determined in this way, the control unit 400 proceeds to step S108 and executes control so that the determined control value is realized. Specifically, the delivery of the droplet 211 from the welding torch 200 is controlled via the discharge unit 420, and the relative movement between the substrate 510 and the welding torch 200 is controlled via the drive unit 440. By such control, the laminated beads achieve a height and an inclination angle that are extremely close to the target values in the cross section with respect to the extending direction of the laminated beads.

In step S109, the control unit 400 determines whether or not the distance D _{0 has been} advanced in the extending direction of the laminated beads. Specifically, the determination is made based on the driving amount driven by the driving unit 440 or the relative movement amount of the substrate 510 and the welding torch 200 fed back. Here, the distance D ₀ may be a predetermined constant value, or may be a variable value until the change amount of the deviation amount d calculated from the path data is out of a predetermined range. Until the distance D ₀ is reached, the control parameter value determined in step S107 is applied and control is continued to return to step S108. The distance _{D 0} proceeds to step S110 When you reach.

  In step S110, control unit 400 determines whether or not the end point has been reached. If it is determined that the end point has not been reached, the process returns to step S102 to continue the formation of the laminated beads. If it is determined that the end point has been reached, it is determined that the modeled object 520 has been completed, and the series of processes ends.

If it is determined in step S102 that the target position of the laminated beads is directly above the lower layer bead, the control unit 400 proceeds to step S111. In step S111, the control unit 400 identifies the target height information as H ₀ from the path data, and determines k, F, and m described above with reference to the lookup table stored in the storage unit 460. Then, the value of the feed speed F of the welding torch 200 is determined from the above equation (6). Of course, the control values of control parameters other than the feed speed F of the welding torch 200 may be changed. When the control value of the control parameter is determined in this way, the control unit 400 proceeds to step S108 and executes the operation as described above.

  In the first embodiment described above, the control is branched depending on whether the laminated bead is laminated immediately above or displaced from the lower layer bead. However, it is also possible to process without branching the control. The second embodiment will be described below.

  FIG. 6 is a flowchart showing a forming process in the second embodiment. The second embodiment is effective when the lower layer bead is not necessarily formed according to the path data and may contain an error. Similar to the first embodiment, a series of flows is started when the setup is completed such that the substrate 510 is fixed to the stage 120 and the cooling bath 300 is filled with cooling water.

  In step S201, the control unit 400 acquires CAD data from the CAD system 700 via the acquisition unit 450. The control unit 400 generates path data for accumulating beads in a one-stroke writing format from the acquired CAD data. The generated path data includes information on the amount of deviation of the stacked bead relative to the lower layer bead, information on the target height of each layer, and the like.

  In step S202, the control unit 400 receives the shape of the lower layer bead measured by the image unit 430. Here, the image unit 430 measures not only the cross-sectional shape but also the position of the center line in the distraction direction, the vector in the distraction direction, and the tilt angle of the surface of the already stacked beads including the lower layer bead, and passes them to the control unit 400. In step S203, the control unit 400 calculates how much the lower layer bead has an error with respect to the design position from the received lower layer bead shape information and path data. In step S204, the target dropping position of the droplet 211 obtained from the pass data is corrected. Thereby, the corrected displacement amount d is determined in step S205. At this time, the displacement amount d may be corrected in consideration of the inclination angle of the surfaces of the already stacked beads. For example, when the inclination angle measured with respect to the design value is large, the displacement amount d may be corrected so that the inclination angle of the laminated beads becomes small. Conversely, when the inclination angle measured is small The displacement amount d may be corrected so that the inclination angle of the laminated beads becomes large.

  In step S206, the control unit 400 applies a quadratic function to the acquired cross-sectional shape of the lower layer bead, and determines the coefficient a described above. In step S207, the control unit 400 calculates the above-described H (θ) from the target height information included in the path data, the corrected deviation amount d, and the like, and the above-described H (θ) corresponding to this H (θ). K, F, and m are determined with reference to a lookup table stored in the storage unit 460. In step S208, arithmetic unit 410 determines the value of feed speed F of welding torch 200 as a control parameter using these determined control values. Of course, as described above, the control values of the control parameters other than the feed speed F of the welding torch 200 may be changed.

  When the control value of the control parameter is determined in this way, the control unit 400 proceeds to step S209 and executes control so that the determined control value is realized. Specifically, the delivery of the droplet 211 from the welding torch 200 is controlled via the discharge unit 420, and the relative movement between the substrate 510 and the welding torch 200 is controlled via the drive unit 440. By such control, the laminated beads achieve a height and an inclination angle that are extremely close to the target values in the cross section with respect to the extending direction of the laminated beads.

In step S210, control unit 400 determines whether or not the distance D _{0 has been} advanced in the extending direction of the laminated beads. Specifically, the determination is made based on the driving amount driven by the driving unit 440 or the relative movement amount of the substrate 510 and the welding torch 200 fed back. Here, the distance D ₀ may be a predetermined constant value, or may be a variable value until the change amount of the deviation amount d calculated from the path data is out of a predetermined range. Moreover, you may change according to the vector of the distraction direction acquired by step S202. For example, the distance D ₀ may be shortened as the measured vector of the lower layer bead is greatly deviated from the vector in the distraction direction by the path data.

Until the distance D ₀ is reached, the control parameter value determined in step S208 is applied and control is continued to return to step S209. The distance _{D 0} processing proceeds to step S211 upon reaching.

  In step S211, the control unit 400 determines whether the end point has been reached. If it is determined that the end point has not been reached, the process returns to step S202 to continue the formation of the laminated beads. If it is determined that the end point has been reached, it is determined that the modeled object 520 has been completed, and the series of processes ends.

  The shaped object 520 is completed by the first embodiment or the second embodiment described above. Thereafter, a finishing process is performed by a processing machine such as a machining center, which is separated from the substrate 510, and a series of steps for manufacturing a three-dimensional shaped object is completed. Of course, if the processing accuracy by the three-dimensional modeling apparatus 100 is sufficient, finishing can be omitted.

  Here are some experimental data. FIG. 7 shows specification values related to the experiment. Here, the welding wire material, the welding wire diameter, the applied current, the applied voltage, the welding torch feed speed, the type and mixing ratio of the shielding gas, and the shielding gas amount are selected as the control parameters to be set. Under these conditions, an experiment was performed to form a modeled object 520 with the three-dimensional shape shown in FIG. 3 as a target.

  FIG. 8 shows the experimental results of modeling with the shape of FIG. 3 as a target. The horizontal axis is the tilt angle set as the design value, and the vertical axis is the error angle of the actually formed surface. The black circle plot is the result of no correction control, and the white circle plot is the result of correction control. As shown in the graph, the error angle is smaller when there is correction control. This is particularly noticeable when the set angle is around 30 °.

  Although the present embodiment and the experimental results have been described above, the correction control can be performed by applying various variations. In this embodiment, the correction control is performed by setting the parameter value for controlling the droplet amount of the droplet to be delivered when the laminated bead is formed by deviating from the center line in the extending direction on the lower layer bead. Although the calculation is performed based on the deviation amount from the line, the parameter value calculated as described above is not limited to the feed speed F of the welding torch 200. For example, the droplet amount may be directly calculated, and related parameter values may be determined so that the droplet amount is delivered. In this case, control may be performed so as to change either the drawing speed of the welding wire 210 that the welding torch 200 draws or the relative speed of the substrate 510 and the welding torch 200.

  Various modes can be adopted for delivery of the droplet 211. By adjusting the applied voltage and current of the power supply unit 201, the amount of droplets delivered at one time can be changed, so that not only a single drop but also a plurality of drops can be applied to the same target position. good.

  Further, if the moving mechanism includes a mechanism for tilting the welding torch 200 with respect to the substrate 510, the control unit 400 may control the tilting of the welding torch 200 according to the tilt angle of the laminated beads with respect to the lower layer bead. good. For example, if the droplets 211 can be dropped along the tilt angle direction, even a tilted surface can be made smooth.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 100 3D modeling apparatus, 110 base, 120 stage, 130 support | pillar, 140 movable arm, 150 holder, 160 guide tube, 200 welding torch, 201 feeding part, 202 shielding gas, 210 welding wire, 211 droplet, 220 image sensor , 300 cooling tank, 310 chuck, 400 control unit, 410 calculation unit, 420 discharge unit, 430 image unit, 440 drive unit, 450 acquisition unit, 460 storage unit, 510 substrate, 520 shaped article, 521 bead, 5211 lower layer bead, 5212 Laminated Bead, 700 CAD System, 901 First Auxiliary Line, 902 Second Auxiliary Line

Claims (20)

A welding torch for sending droplets of metal wire melted by arc discharge in the direction of the opposing substrate;
A moving mechanism for relatively moving the substrate and the welding torch;
When the second weld bead is formed by laminating the first weld bead formed by the droplet from the center line in the extending direction of the first weld bead, the droplet of the droplet to be sent out is formed. A calculation unit for calculating a parameter value for controlling the amount based on a deviation amount from the center line;
A three-dimensional modeling apparatus comprising: a control unit that controls the welding torch and the moving mechanism based on the parameter value calculated by the calculation unit.   The control unit changes at least one of a drawing speed of the metal wire drawn by the welding torch and a relative speed of the substrate and the torch based on the parameter value calculated by the calculating unit. The three-dimensional modeling apparatus described in 1.   The said calculating part approximates the upper surface of the said 1st weld bead which the said 2nd weld bead contacts with the quadratic function which makes the said centerline the vertex in the cross section orthogonal to the said extension direction. 3D modeling equipment. A storage unit for storing a lookup table in which parameter values forming the first weld bead and coefficients of the quadratic function are associated;
The three-dimensional modeling apparatus according to claim 3, wherein the calculation unit determines the quadratic function with reference to the lookup table. Prior to the delivery of the droplets for forming the second weld bead, a cross-section measurement unit that measures the shape of the cross section of the first weld bead,
The three-dimensional modeling apparatus according to claim 3, wherein the calculation unit determines the quadratic function based on a cross-sectional shape measured by the cross-section measurement unit.   The calculation unit is configured to determine a relative speed between the substrate and the torch in a vertical line passing through the center line in the cross section perpendicular to the extending direction of the first weld bead, the center line, and the second line. The three-dimensional modeling apparatus according to any one of claims 1 to 5, wherein the three-dimensional modeling apparatus is derived as a function of an inclination angle formed by an inclination line connecting a vertex of a target height of the weld bead.   The three-dimensional modeling apparatus according to claim 6, wherein the calculation unit acquires the tilt angle based on CAD data. Prior to the delivery of the droplets to form the second weld bead, an inclination measuring unit that measures the inclination of the already stacked weld beads including the first weld bead,
The three-dimensional modeling apparatus according to claim 6 or 7, wherein the calculation unit corrects the tilt angle based on the tilt measured by the tilt measuring unit. The moving mechanism includes a mechanism for tilting the torch with respect to the substrate;
The three-dimensional modeling apparatus according to claim 6, wherein the control unit tilts the torch based on the tilt angle.   The three-dimensional modeling apparatus according to any one of claims 1 to 9, wherein the control unit continuously forms a boundary portion from the first weld bead to the second weld bead. A welding torch for sending droplets of metal wire melted by arc discharge in the direction of the opposing substrate;
A moving mechanism for relatively moving the substrate and the torch;
A measuring unit for measuring the shape of the first weld bead formed by the droplets;
A parameter value for controlling the amount of droplets to be delivered when the first weld bead is formed by laminating the second weld bead by deviating from the center line in the extending direction of the first weld bead. Calculating unit based on the amount of deviation from the center line and the measurement result of the measurement unit,
A three-dimensional modeling apparatus comprising: a control unit that controls the welding torch and the moving mechanism based on the parameter value calculated by the calculation unit.   The control unit changes at least one of a drawing speed of the metal wire drawn by the welding torch and a relative speed of the substrate and the torch based on the parameter value calculated by the calculation unit. The three-dimensional modeling apparatus described in 1.   The calculation unit approximates the upper surface of the first weld bead with which the second weld bead is in contact with a quadratic function having the center line as a vertex in a cross section orthogonal to the extending direction. 3D modeling equipment.   The calculation unit is configured to determine a relative speed between the substrate and the torch in a vertical line passing through the center line in the cross section perpendicular to the extending direction of the first weld bead, the center line, and the second line. The three-dimensional modeling apparatus according to any one of claims 11 to 13, wherein the three-dimensional modeling apparatus is derived as a function of an inclination angle formed by an inclination line connecting a vertex of a target height of the weld bead. The moving mechanism includes a mechanism for tilting the torch with respect to the substrate;
The three-dimensional modeling apparatus according to claim 11, wherein the control unit tilts the torch based on the deviation amount.   The three-dimensional modeling apparatus according to claim 11, wherein the control unit continuously forms a boundary portion from the first weld bead to the second weld bead. The second weld bead is displaced from the center line in the extending direction of the first weld bead on the first weld bead formed by sending a molten metal melted by arc discharge in the direction of the opposing substrate. When forming by laminating, a calculation step of calculating a parameter value for controlling the droplet amount of the droplet to be sent out based on the deviation amount from the center line,
Three-dimensional modeling having a welding torch for delivering the droplets and a control step for controlling a moving mechanism for relatively moving the substrate and the welding torch based on the parameter value calculated by the calculation step Method for modeling objects. A measuring step of measuring the shape of the first weld bead formed by sending a molten metal melted by arc discharge in the direction of the opposing substrate;
A parameter value for controlling the amount of droplets to be delivered when the first weld bead is formed by laminating the second weld bead by deviating from the center line in the extending direction of the first weld bead. Calculating step based on the amount of deviation from the center line and the measurement result of the measuring step,
Three-dimensional modeling having a welding torch for delivering the droplets and a control step for controlling a moving mechanism for relatively moving the substrate and the welding torch based on the parameter value calculated by the calculation step Method for modeling objects. The second weld bead is displaced from the center line in the extending direction of the first weld bead on the first weld bead formed by sending a molten metal melted by arc discharge in the direction of the opposing substrate. A calculation step of calculating a parameter value for controlling the droplet amount of the droplet to be sent out based on the deviation amount from the center line when forming by laminating,
Based on the parameter value calculated in the calculation step, the computer executes a welding torch for sending the droplet and a control step for controlling a moving mechanism for relatively moving the substrate and the welding torch. Control program for 3D manufacturing equipment. A measurement step of measuring the shape of the first weld bead formed by sending a molten metal melted by arc discharge in the direction of the opposing substrate;
A parameter value for controlling the amount of droplets to be delivered when the first weld bead is formed by laminating the second weld bead by deviating from the center line in the extending direction of the first weld bead. A calculation step for calculating a deviation amount from the center line and a measurement result of the measurement step;
Based on the parameter value calculated in the calculation step, the computer executes a welding torch for sending the droplet and a control step for controlling a moving mechanism for relatively moving the substrate and the welding torch. Control program for 3D manufacturing equipment.

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