JP6753989B1 - Laminate planning method of laminated model, manufacturing method and manufacturing equipment of laminated model - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for planning a stacking of a laminated model, a method for producing a laminated model, and a manufacturing apparatus capable of appropriately controlling the temperature between passes to form a model in an optimum modeling time. SOLUTION: For a plurality of welding passes, a step of setting an inter-pass time tun, performing a heat transfer calculation at the inter-pass time tun to calculate an inter-pass temperature Tn, and an inter-pass temperature Tn preset. It is calculated by the process of determining whether or not it falls within the range Tmin to Tmax and adjusting the inter-pass time tun by repeating the heat transfer calculation until the inter-pass temperature Tn falls within the inter-pass temperature range Tmin to Tmax, and the heat transfer calculation. Including a step of calculating the modeling time ta for modeling the laminated model W based on the inter-pass time tn and the welding pass time tpn, the modeling time ta is compared with the preset upper limit value tmax, and the modeling time is compared. The welding conditions in the lamination plan are repeatedly modified until ta becomes equal to or less than the upper limit value tmax. [Selection diagram] Fig. 4

Description

The present invention relates to a method for planning a laminate of a laminated model, a method for producing a laminated model, and a manufacturing apparatus.

In recent years, there has been an increasing need for modeling using a 3D printer as a means of production, and research and development are being promoted toward the practical application of modeling using metal materials. A 3D printer for modeling a metal material uses a heat source such as a laser, an electron beam, or an arc to melt a metal powder or a metal wire and laminate the molten metal to produce a laminated model.

In addition, as a technique for predicting the temperature of the welded portion, the welding conditions such as the cooling rate are changed to various values such as the interpass temperature, which is the allowable temperature of the welded portion when the welding of the next pass is started, and the amount of heat input. For example, Patent Document 1 describes the adjustment.

Japanese Unexamined Patent Publication No. 2004-4034

By the way, in multi-layer welding in which beads are laminated, the welding temperature is monitored under predetermined construction conditions (plate thickness, number of passes, current, voltage, speed, arc time, etc.) and waits until the predetermined inter-pass temperature. Time data is acquired by experiment, and the inter-pass temperature is controlled based on the acquired data.

However, when a modeled object having a complicated shape is manufactured by laminated modeling, the shape changes as the number of laminated objects increases, so that the overall heat capacity and heat conduction change. In addition, the welding conditions may be changed during modeling depending on the shape of the modeled object. Therefore, in the above-mentioned method of controlling the inter-pass temperature, it is necessary to carry out a large amount of experiments and collect data in order to obtain an appropriate waiting time. For example, when the number of welding passes is several hundred, it is unrealistic because it takes a lot of time and effort. Further, if the temperature between passes is too high, the bead may hang down and the bead shape may be deformed. If the inter-pass temperature is too low, the waiting time for cooling to the inter-pass temperature becomes long, and as a result, the manufacturing time of the modeled object becomes long. Moreover, since the inter-pass temperature changes depending on the welding material, the base material, and the welding method, it is difficult to properly control the inter-pass temperature. Then, in the technique described in Patent Document 1 for welding the groove of the base metal, it is difficult to appropriately control the inter-pass temperature in the laminated molding.

Further, in the laminated modeling technique, since the material is melted and solidified to form the model, the modeled object may be thermally contracted and deformed, and an error may occur with respect to the target shape. Further, when the modeled object is processed by cutting, annealing, or removing the base plate, strain may be generated by releasing the thermal stress remaining inside the modeled object, and the modeled object may be deformed.

Therefore, the present invention provides a method for planning the lamination of a laminated model, a method for producing a laminated model, and a manufacturing apparatus capable of appropriately controlling the temperature between passes to form a model in an optimum modeling time. With the goal.

The present invention has the following configuration.
(1) A method for planning the lamination of a laminated model in which a laminated model is formed by using a laminated modeling device for laminating weld beads on a base plate using the three-dimensional shape data of the laminated model.
Computer
The process of acquiring the three-dimensional shape data and
A step of creating a welding path for forming each layer obtained by layering the shape of the three-dimensional shape data with the welding bead, and a laminating plan for defining welding conditions when forming the welding bead.
For the plurality of welding paths, a step of setting the inter-pass time from the end of the welding path to the start of the next welding path, performing heat transfer calculation in the inter-pass time, and calculating the inter-pass temperature.
A step of determining whether or not the inter-pass temperature falls within a preset inter-pass temperature range, adjusting the inter-pass time, and repeating the heat transfer calculation until the inter-pass temperature falls within the inter-pass temperature range. ,
Depending on the inter-pass time when the inter-pass temperature within the inter-pass temperature range is calculated and the welding pass time required for forming the welding bead in the welding pass, the laminated model is formed. The process of calculating the required molding time and
A step of repeatedly modifying the welding conditions in the lamination plan until the molding time becomes equal to or less than the upper limit value by comparing the molding time with a preset upper limit value.
A method of laminating a laminated model to execute.
(2) A method for manufacturing a laminated model, which manufactures the laminated model based on the laminated plan created by the method for planning the layered model according to (1).
(3) An apparatus for manufacturing a laminated model, in which a welded bead is laminated on a base plate to form the laminated model using three-dimensional shape data of the laminated model.
An input unit for acquiring the three-dimensional shape data and
A laminating plan creation unit that creates a welding path for forming each layer obtained by layering the shape of the three-dimensional shape data with the welding bead, and a laminating plan that defines welding conditions when forming the welding bead.
For the plurality of welding paths, a temperature prediction unit that sets the inter-pass time from the end of the welding path to the start of the next welding path, performs heat transfer calculation in the inter-pass time, and calculates the inter-pass temperature.
It is determined whether or not the inter-pass temperature falls within the preset inter-pass temperature range, and the inter-pass time is changed and the heat transfer calculation is repeated until the inter-pass temperature falls within the inter-pass temperature range. Temperature control unit and
Depending on the inter-pass time when the inter-pass temperature within the inter-pass temperature range is calculated and the welding pass time required for forming the welding bead in the welding pass, the laminated model is formed. A modeling time estimation unit that calculates the required modeling time, and
A welding condition adjusting unit that repeatedly changes the welding conditions in the lamination plan until the molding time becomes equal to or less than the upper limit value by comparing the molding time with a preset upper limit value.
Equipment for manufacturing laminated objects.

According to the present invention, it is possible to appropriately control the inter-pass temperature and model a modeled object in an optimum modeling time.

It is a schematic block diagram of the manufacturing apparatus of the laminated model which concerns on this invention. It is the schematic cross-sectional view which cut | cut the laminated object in the vertical direction. It is a process explanatory drawing explaining the procedure of the basic laminated molding of a laminated model, and is the schematic cross-sectional view which cut | cut the laminated model in the vertical direction. It is a process explanatory drawing explaining the procedure of the basic laminated molding of a laminated model, and is the schematic cross-sectional view which cut | cut the laminated model in the vertical direction. It is a process explanatory drawing explaining the procedure of the basic laminated molding of a laminated model, and is the schematic cross-sectional view which cut | cut the laminated model in the vertical direction. It is a flowchart which shows the procedure of the stacking plan of a laminated model. It is a flowchart which shows the procedure of the stacking plan of a laminated model considering heat shrinkage.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Manufacturing equipment for laminated objects>
FIG. 1 is a schematic configuration diagram of a manufacturing apparatus for a laminated model according to the present invention.
The laminated model manufacturing apparatus 100 having this configuration includes a modeling unit 11, a controller 13 that controls the modeling unit 11, and a power supply device 15.

The modeling unit 11 includes a welding robot 19 provided with a torch 17 on the tip shaft, and a filler material supply unit 21 that supplies a filler metal (welding wire) M to the torch 17.

The welding robot 19 is an articulated robot, and the filler metal M is continuously supplied to the torch 17 attached to the tip shaft of the robot arm. The position and posture of the torch 17 can be arbitrarily set three-dimensionally within the range of the degree of freedom of the robot arm.

The torch 17 generates an arc from the tip of the filler metal M in a shield gas atmosphere while holding the filler metal M. The torch 17 has a shield nozzle (not shown), and shield gas is supplied from the shield nozzle. The arc welding method may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding, and is appropriately selected according to the laminated model to be manufactured. Weld.

For example, in the case of the consumable electrode type, a contact tip is arranged inside the shield nozzle, and the filler metal M to which the melting current is supplied is held by the contact tip. The torch 17 generates an arc from the tip of the filler metal M in a shield gas atmosphere while holding the filler metal M. The filler metal M is fed from the filler metal supply unit 21 to the torch 17 by a feeding mechanism (not shown) attached to a robot arm or the like. Then, when the filler metal M that is continuously fed is melted and solidified while moving the torch 17, a linear welded bead B that is a molten solidified body of the filler metal M is formed on the base plate 23.

The filler metal M is fed from the filler metal supply unit 21 to the torch 17 by a feeding mechanism (not shown) attached to the robot arm or the like of the welding robot 19. Then, the torch 17 moves along a desired welding line by driving the robot arm by a command from the controller 13. Further, the filler metal M that is continuously fed is melted and solidified in a shield gas atmosphere by an arc generated at the tip of the torch 17. As a result, the weld bead B, which is a melt-solidified body of the filler metal M, is formed. As described above, the modeling unit 11 is a laminated modeling device for laminating the molten metal of the filler metal M, and the laminated model W is modeled by laminating the welded beads B in a multi-layered manner on the base plate 23.

The heat source for melting the filler metal M is not limited to the above-mentioned arc. For example, a heat source by another method such as a heating method using both an arc and a laser, a heating method using plasma, and a heating method using an electron beam or a laser may be adopted. When an arc is used, the welded bead B can be easily formed regardless of the material and structure while ensuring the shielding property. When heating with an electron beam or a laser, the amount of heating can be controlled more finely, the state of the welded bead B can be maintained more appropriately, and the quality of the laminated model W can be further improved.

The controller 13 includes a stacking plan creation unit 31, a deformation amount calculation unit 33, a surplus wall amount setting unit 34, a program generation unit 35, a temperature prediction unit 36, a modeling time estimation unit 38, and a storage unit 37. It has an input unit 39, a display unit 40, and a control unit 41 to which each of these units is connected. Three-dimensional shape data (CAD data, etc.) representing the shape of the laminated model W to be manufactured and various instruction information are input to the control unit 41 from the input unit 39. The display unit 40 displays various types of information according to the signal transmitted from the control unit 41.

The laminated model manufacturing apparatus 100 having this configuration generates a shape model for bead formation using the input three-dimensional shape data, and creates a stacking plan such as a movement locus of the torch 17 and welding conditions. The control unit 41 creates an operation program according to the stacking plan, and drives each unit according to this operation program to laminate and model the laminated model W having a desired shape.

The stacking plan creation unit 31 decomposes the shape model of the input three-dimensional shape data into a plurality of layers according to the height of the welded bead B. Then, for each layer of the decomposed shape model, the trajectory of the torch 17 for forming the welded bead B and the heating conditions (bead width, bead stacking height, etc.) for forming the welded bead B are set. Create a stacking plan that defines (including).

The deformation amount calculation unit 33 analytically obtains the deformation amount generated by the release of the residual stress of the laminated model W when the machine opening or the like is performed on the laminated model W formed according to the lamination plan.

The surplus wall amount setting unit 34 sets the surplus wall amount to be a cutting allowance from the machined structure W1 to the outer edge of the laminated model W.

The program generation unit 35 creates an operation program that causes a computer to execute a procedure of driving each part of the modeling unit 11 to form a laminated model W. The created operation program is stored in the storage unit 37.

The temperature prediction unit 36 has a preliminary prediction means such as a heat transfer calculation described in detail later, and manages the temperature of the welded beam by predicting the temperature before modeling. In addition, the modeling time estimation unit 38 estimates in advance the modeling time required to model the laminated model W, which will be described in detail later.

In addition to storing the operation program, the storage unit 37 also stores specifications of various drive units of the modeling unit 11, information on the material of the filler metal M, and the like. The stored information is appropriately referred to when the program generation unit 35 creates an operation program, executes the operation program, and the like.

The controller 13 including the control unit 41 is a computer including a processor such as a CPU, a memory such as a ROM or a RAM, a storage such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), an I / O interface, and the like. Consists of. The controller 13 has a function of reading data and programs stored in the storage unit 37, executing data processing including analysis processing and an operation program, and a function of driving and controlling each part of the modeling unit 11. The control unit 41 creates and executes various operation programs based on an operation from the input unit 39 or an instruction by communication or the like.

When the control unit 41 executes the operation program, each unit such as the welding robot 19 and the power supply device 15 is driven according to a predetermined programmed procedure. The welding robot 19 moves the torch 17 along the programmed trajectory according to the command from the controller 13, and melts the filler metal M by an arc at a predetermined timing to bring the welding bead B to a desired position. Form.

The operation program referred to here is an instruction code for causing the modeling unit 11 to carry out the forming procedure of the welded bead B designed by a predetermined calculation from the input three-dimensional shape data of the laminated model W. The control unit 41 causes the modeling unit 11 to manufacture the laminated model W by executing the operation program stored in the storage unit 37. That is, the control unit 41 reads a desired operation program from the storage unit 37, moves the torch 17 by driving the welding robot 19 according to this operation program, and generates an arc from the tip of the torch 17. As a result, the welded bead B is repeatedly formed on the base plate 23 to form the laminated model W.

Each calculation unit such as the stacking plan creation unit 31, the deformation amount calculation unit 33, the surplus thickness setting unit 34, the program generation unit 35, the temperature prediction unit 36, and the modeling time estimation unit 38 is provided in the controller 13, but is limited to this. Absent. Although not shown, the above-mentioned calculation unit is provided on an external computer such as a server or a terminal which is separated from the manufacturing apparatus 100 for a laminated model, for example, by means of a communication means such as a network. May be good. By providing the above-mentioned calculation unit in the external computer, it is possible to create a desired operation program without requiring the manufacturing apparatus 100 for the laminated model, and the program creation work is not complicated. Further, by transferring the created operation program to the storage unit 37 of the controller 13 via a network or a storage medium, the modeling unit 11 can be operated in the same manner as when the operation program is created by the controller 13. ..

<Basic procedure for laminated molding>
Next, the procedure of the laminated modeling will be briefly described using the model of the simple laminated model W.
FIG. 2 is a schematic cross-sectional view of the laminated model W cut in the vertical direction. 3A to 3C are process explanatory views for explaining the basic procedure of the laminated modeling of the laminated model W, and are schematic cross-sectional views of the laminated model W cut in the vertical direction.

The laminated model W shown as an example in FIG. 2 is formed in a cylindrical shape on the base plate 23. The base plate 23 is made of a metal plate such as a steel plate, and basically, a base plate 23 larger than the bottom surface (bottom layer surface) of the laminated model W is used. The base plate 23 is not limited to a plate shape, and may be a base having another shape such as a block body or a rod shape.

As shown in FIG. 3A, in order to form the laminated model W, the welding robot 19 moves the torch 17 along the instructed trajectory according to the operation program on the base plate 23 installed in advance. By generating an arc at the tip of the torch 17 with the movement of the torch 17, a welded bead B is formed along the trajectory of the torch 17. The weld bead B is formed by melting and solidifying the filler metal M. Then, the bead layer BL of the next layer is repeatedly laminated on the formed bead layer BL by the same operation as described above.

As shown in FIG. 3B, after the laminated model W is formed on the base plate 23, the base plate 23 is cut by a cutting machine such as a wire saw or a diamond cutter to separate the base plate 23 and the laminated model W. Remove the base plate 23. After that, as shown in FIG. 3C, for example, the surplus portion set by the surplus amount setting unit 34 is cut with respect to the laminated model W and processed into a product. The base plate 23 may be removed after cutting the excess wall portion from the laminated model W.

<Laminating plan for laminated objects>
Next, a laminating planning method for modeling a laminated model will be described.
Here, when the laminated model W as described above is modeled by laminating the welded beads B, the temperature between passes of the welded beads B is appropriately controlled, and the laminated model W is modeled in the optimum modeling time. Make a plan.

FIG. 4 is a flowchart showing a procedure for laminating a laminated model.
First, the controller 13 acquires the three-dimensional shape data D ₀ , which is the CAD data of the laminated model to be modeled, from the input unit 39 (S1).

The stacking plan creation unit 31 of the controller 13 determines the modeling shape according to the acquired three-dimensional shape data D ₀ , creates a stacking plan for forming the modeling shape with the welding beads B, and forms the welding beads B. The condition is determined (S2). To determine the conditions, create a trajectory plan to determine the welding path (torch trajectory) to move the torch 17, and to form the welding bead B using an arc as a heating source, the welding current, arc voltage, welding speed, and so on. It includes setting various welding conditions such as torch angle.

Specifically, the modeling shape of the laminated model W is determined from the three-dimensional shape data D ₀ , and this modeling shape is vertically divided into a plurality of bead layers (10 layers in this example) BL, and each bead layer BL. Correspondingly, the welding path for moving the torch 17 is obtained. The welding path is determined by an operation based on a predetermined algorithm. The welding path information includes, for example, path information such as the spatial coordinates of the path for moving the torch 17, the radius of the path, and the path length, and bead information such as the bead width and bead height of the welded bead B to be formed. included. The height of the bead layer BL is determined according to the height of the welded bead B set by the welding conditions.

After creating the stacking plan, the temperature prediction process (S3 to S7) is performed by the temperature prediction unit 36.

First, for the welding paths in the lamination plan, the inter-pass time tun, which is the waiting time from the end of one welding path to the start of the next welding path, is set. Further, in the inter-pass time tn, the maximum value Tmin and the minimum value Tmin of the permissible inter-pass temperature are set in advance (S3).

Next, the inter-pass temperature Tn at each welding pass at the inter-pass time tun is calculated by performing heat transfer calculation described in detail later (S4).

It is determined whether or not the calculated inter-pass temperature Tn in each welding pass falls within the allowable inter-pass temperature range Tmin to Tmax (S5). When the inter-pass temperature Tn is out of the inter-pass temperature range Tmin to Tmax (S5: No), the inter-pass time nt is changed again so that the inter-pass temperature Tn falls within the inter-pass temperature range Tmin to Tmax. The heat transfer is calculated, and the inter-pass temperature Tn is calculated (S4).

In this way, the heat transfer calculation is repeated by changing the inter-pass time tn until the inter-pass temperature Tn falls within the inter-pass temperature range Tmin to Tmax for all the divided bead layer BLs (S6). This process is executed by the temperature prediction unit 36 having the function of the inter-pass temperature adjustment unit that repeats the heat transfer calculation.

When the inter-pass temperature Tn for all the divided bead layers BL falls within the inter-pass temperature range Tmin to Tmax (S6: Yes), the inter-pass time tun and the inter-pass temperature Tn in each welding pass are output to the control unit 41. (S7).

Here, it is preferable to use a method having a high calculation speed for the heat transfer calculation by the temperature prediction unit 36. This heat transfer calculation may be calculated using a three-dimensional heat conduction equation. The temperature prediction unit 36 predicts the temperature using, for example, the following basic formula (1).

However, in the basic formula (1),
H: Entalpi
C: Reciprocal of node volume
K: Heat conduction matrix
F: Heat flux
Q: Volumetric heat generation.

In the three-dimensional heat conduction equation, the welding heat input may be applied to the welding region according to the welding speed. Further, when the welded bead is short, heat input for the entire bead may be applied.

After the temperature prediction unit 36 outputs the inter-pass time tn and the inter-pass temperature Tn to the control unit 41, the modeling time estimation unit 38 performs the following modeling time estimation processing (S8, S9).

The modeling time estimation unit 38 inputs the inter-pass time nt and the inter-pass temperature Tn in each welding pass for all the divided bead layer BLs from the control unit 41. Then, according to the calculated inter-pass time tn and the welding pass time tpn required for forming the welded bead in the welding pass, the modeling time ta required for modeling the laminated model W is calculated from the following calculation formula (2). Calculate (S8). That is, the total molding time ta of the laminated model W is estimated by adding the integrated value of the inter-pass time tun to the welding pass time tpn. The modeling time ta may include the operating time of the welding robot 19.

However, in the calculation formula (2),
ta: Total modeling time
tp (i): Welding time of the welding path of the i-th layer
tn (i + 1): The time between the welding path of the i-th layer and the path of the (i + 1) layer.

After calculating the modeling time ta by the calculation formula (2), the modeling time ta is compared with the preset upper limit value tmax (S9). The upper limit value tmax is a time set in consideration of the productivity of the laminated model W, and is, for example, a time limit of the time required for modeling the laminated model W.

That is, when the modeling time ta exceeds the upper limit value tmax (S9: No), the productivity of the laminated model W is low, and it is determined that improvement is necessary. In that case, a stacking plan is created again (S2), and temperature prediction processing (S3 to S7) and modeling time ta estimation processing (S8, S9) are performed based on the created stacking plan. This process is executed by the modeling time estimation unit 38 having the function of the welding condition adjusting unit that repeatedly changes the welding conditions.
In this way, the modification of the stacking plan (S2), the temperature prediction processing (S3 to S7), and the estimation processing of the modeling time ta (S8, S9) are repeated until the modeling time ta becomes equal to or less than the upper limit value tmax.

Here, the modification of the laminating plan is a modification to increase the molding speed, for example, the welding conditions are modified, the laminating order of the welded beads B is changed, and the like. When modifying the welding conditions, any one of the welding speed, the number of passes, and the shape of the welded bead B (bead width, bead height) is modified. For example, the bead shape (bead width, bead height) of each condition may be stored in a database in advance and stored in the storage unit 37, and the welding conditions corresponding to the target shape dimension and the molding time ta may be selected.

As described above, according to the laminating planning method of the laminated model of the present configuration, the inter-pass time tun is set for a plurality of welding passes, the heat transfer calculation at the inter-pass time tun is performed, and the inter-pass temperature Tn. Is calculated, it is determined whether or not the inter-pass temperature Tn falls within the preset inter-pass temperature range Tmin to Tmax, and the heat transfer calculation is repeated until the inter-pass temperature Tn falls within the inter-pass temperature range Tmin to Tmax. Adjust the interim time. Then, the modeling time ta for modeling the laminated model W is calculated according to the inter-pass time tn and the welding pass time tpn calculated by the heat transfer calculation. Further, the molding time ta is compared with the preset upper limit value tmax, and the welding conditions in the lamination plan are repeatedly modified until the molding time ta becomes equal to or less than the upper limit value tmax. Therefore, the molding time ta can be shortened by appropriately controlling the inter-pass temperature Tn of the welding path when forming the welded bead B and changing the welding conditions in the lamination plan.

In particular, the molding time ta can be efficiently shortened by changing the welding speed, the number of passes, and the bead shape under the welding conditions.

As a result, the laminated model W can be manufactured by shortening the modeling time ta while appropriately controlling the inter-pass temperature Tn of the welding path when forming the welded bead B.

By the way, in the laminated modeling method in which the welded bead B is laminated on the base plate 23 to form the laminated model W, the material is melted and solidified to form the model, so that residual stress is generated inside the laminated model W due to heat shrinkage or the like. It may have occurred. Then, when the laminated model W is cut, annealed, or the base plate 23 is removed, deformation occurs due to the release of the residual stress, and an error occurs with respect to the target shape. In order to suppress an error with respect to the target shape, it is necessary to set a large amount of surplus wall and then perform cutting or the like. However, if the surplus thickness is set in consideration of the release strain, the molding time increases.

Therefore, in the laminated model manufacturing apparatus 100 having this configuration, the deformation amount calculation unit 33 predicts the amount of deformation caused by the heat shrinkage of the laminated model W, and the surplus wall amount setting unit 34 determines the amount of deformation caused by the heat shrinkage of the laminated model W. The surplus thickness δ is adjusted, and the modeling time estimation unit 38 corrects the modeling time ta based on the adjustment of the surplus thickness δ.

Hereinafter, a case where the modeling time ta is corrected by adjusting the surplus thickness δ will be described.
FIG. 5 is a flowchart showing a procedure for laminating a laminated model in consideration of heat shrinkage.

When the inter-pass time nt and the inter-pass temperature Tn in each welding pass for all the divided bead layer BLs are output, the deformation amount calculation unit 33 is based on the calculated inter-pass time nt and the inter-pass temperature Tn. Predicts the amount of deformation of the laminated model W, and creates the model shape data D ₁ of the laminated model W when it is heat-shrinked (S11).

The modeled object shape data D ₁ and the three-dimensional shape data D ₀ are compared with each other, and the surplus wall amount setting unit 34 calculates the surplus wall amount δ from the difference (S12).

Further, from the calculated surplus thickness δ, the modeling time estimation unit 38 estimates the cutting time ct required when the laminated model W is machined into the shape of the structure W1 (S13).

After that, the modeling time ta obtained in the modeling time estimation process (S8, S9) is corrected to the modeling time ta to which the estimated cutting time ct is added (S14).

By doing so, it is possible to appropriately calculate the surplus wall amount δ, which is the portion to be cut after laminating the welded beads B, and suppress the total modeling time ta including the cutting time ct required for cutting the surplus wall portion. ..

Here, the welding deformation and residual stress of the laminated model are generally analyzed by a thermal elasto-plastic analysis method using a finite element method (FEM) or a computer simulation using an elastic analysis or the like.

In the thermal elasto-plastic analysis method, since the phenomenon is calculated in consideration of various non-linear elements for each of a large number of minute time steps, highly accurate analysis can be performed. On the other hand, in the elastic analysis, since the analysis considers only the linear elements, the analysis can be performed in a short time. When the laminated model W is formed by laminating the weld beads B, all the parts of the laminated model W undergo a metal melting / solidification process. When the metal melts and solidifies, natural strain (plastic strain, thermal strain) is generated in the laminated model W. Residual stress due to this natural strain is generated inside the laminated model W. The deformation amount calculation unit 33 analytically obtains a shape change due to such laminated modeling.

The deformation amount calculation unit 33 may be configured to include, for example, a partial model thermal elasto-plastic analysis unit and an overall model elasticity analysis unit. The partial model thermal elasto-plastic analysis unit performs thermal elasto-plastic analysis using a partial model of the modeled object based on the input analysis conditions (laminated modeling conditions, material physical property conditions), and the intrinsic strain (plastic strain, Thermal strain) is calculated. The overall model elasticity analysis unit performs elastic analysis on the entire model of the modeled object based on the calculated intrinsic strain and derives residual stress and the like. The conditions used for the analysis include laminated molding conditions with parameters such as heat source output, heat source type, beam profile, scanning speed, scanning sequence, line offset or preheating temperature, and Young's modulus, proof stress, and linear expansion of the material. There are mechanical property values such as a coefficient and a work hardening index, and material property conditions such as a thermal property value such as thermal conductivity or specific heat.

The present invention described above is not limited to the above-described embodiment, and can be modified or applied by those skilled in the art based on the combination of each configuration of the embodiments, the description of the specification, and well-known techniques. This is also the subject of the present invention and is included in the scope for which protection is sought.

For example, in the above example, the laminated model W has a simple cylindrical shape, but the shape of the laminated model W is not limited to this. The more complicated the shape of the laminated model W is, the more remarkable the effects of the above-mentioned lamination plan and manufacturing method are, so that the present invention can be suitably applied.

As described above, the following matters are disclosed in this specification.
(1) A method for planning the lamination of a laminated model in which a laminated model is formed by using a laminated modeling device for laminating weld beads on a base plate using the three-dimensional shape data of the laminated model.
Computer
The process of acquiring the three-dimensional shape data and
A step of creating a welding path for forming each layer obtained by layering the shape of the three-dimensional shape data with the welding bead, and a laminating plan for defining welding conditions when forming the welding bead.
For the plurality of welding paths, a step of setting the inter-pass time from the end of the welding path to the start of the next welding path, performing heat transfer calculation in the inter-pass time, and calculating the inter-pass temperature.
A step of determining whether or not the inter-pass temperature falls within a preset inter-pass temperature range, adjusting the inter-pass time, and repeating the heat transfer calculation until the inter-pass temperature falls within the inter-pass temperature range. ,
Depending on the inter-pass time when the inter-pass temperature within the inter-pass temperature range is calculated and the welding pass time required for forming the welding bead in the welding pass, the laminated model is formed. The process of calculating the required molding time and
A step of repeatedly modifying the welding conditions in the lamination plan until the molding time becomes equal to or less than the upper limit value by comparing the molding time with a preset upper limit value.
A method of laminating a laminated model to execute.
According to the laminating planning method of the laminated model having this configuration, it is possible to reduce the molding time by modifying the welding conditions in the laminating plan while appropriately controlling the inter-pass temperature of the welding path when forming the welding bead. ..

(2) The method for planning the lamination of a laminated model according to (1), wherein the modification of the welding condition is to modify any of the welding speed, the number of passes, and the bead shape.
According to the laminating planning method of the laminated model having this configuration, the modeling time can be satisfactorily suppressed by modifying the welding conditions such as the welding speed, the number of passes, or the bead shape.

(3) The computer
Based on the inter-pass time calculated after the heat transfer calculation is completed and the inter-pass temperature, a step of creating model shape data of the laminated model when heat shrinks,
A step of calculating the amount of surplus from the difference between the modeled object shape data and the modeled shape of the three-dimensional shape data, and
A step of estimating the cutting time, which is the processing time for the laminated model, from the surplus thickness,
And carry out
The laminating planning method for a laminated model according to (1) or (2), wherein the modification is performed by adding the cutting time to the modeling time.
According to the laminating planning method of the laminated model having this configuration, the amount of surplus wall to be cut after laminating the welded beads is appropriately calculated, and the entire modeling including the cutting time required for cutting this surplus wall portion is included. You can save time.

(4) A method for manufacturing a laminated model, which manufactures the laminated model based on the laminated plan created by the method for planning the lamination of the laminated model according to any one of (1) to (3).
According to the method for manufacturing a laminated model having this configuration, the temperature between the welding paths when forming the welding bead is appropriately controlled, and the welding conditions in the welding plan are modified to reduce the molding time and the laminated model. Can be manufactured.

(5) An apparatus for manufacturing a laminated model, in which a welded bead is laminated on a base plate to form the laminated model using three-dimensional shape data of the laminated model.
An input unit for acquiring the three-dimensional shape data and
A lamination plan creation unit that creates a welding path for forming each layer obtained by layering the shape of the three-dimensional shape data with the welding bead, and a lamination plan that defines welding conditions when forming the welding bead.
For the plurality of welding paths, a temperature prediction unit that sets the inter-pass time from the end of the welding path to the start of the next welding path, performs heat transfer calculation in the inter-pass time, and calculates the inter-pass temperature.
It is determined whether or not the inter-pass temperature falls within the preset inter-pass temperature range, and the inter-pass time is changed and the heat transfer calculation is repeated until the inter-pass temperature falls within the inter-pass temperature range. Temperature control unit and
Depending on the inter-pass time when the inter-pass temperature within the inter-pass temperature range is calculated and the welding pass time required for forming the welding bead in the welding pass, the laminated model is formed. A modeling time estimation unit that calculates the required modeling time, and
A welding condition adjusting unit that repeatedly changes the welding conditions in the lamination plan until the molding time becomes equal to or less than the upper limit value by comparing the molding time with a preset upper limit value.
Equipment for manufacturing laminated objects.
According to the manufacturing equipment for the laminated model having this configuration, the temperature between the welding paths when forming the welding bead is appropriately controlled, and the welding conditions in the welding plan are modified to reduce the molding time and the laminated model. Can be manufactured.

23 Base plate 31 Lamination plan creation unit 33 Deformation amount calculation unit 34 Surplus thickness setting unit 35 Program generation unit 36 Temperature prediction unit 37 Storage unit 38 Modeling time estimation unit 39 Input unit 40 Display unit 100 Welding bead D ₀ 3D shape data D ₁ Modeled object shape data Tn Inter-pass temperature ta Modeling time ct Cutting time tpn Welding pass time tun Inter-pass time W Laminated model δ Surplus thickness

Claims (5)

This is a laminating planning method for a laminated model in which a laminated model is modeled using the three-dimensional shape data of the laminated model by a laminated modeling device for laminating weld beads on a base plate.
Computer
The process of acquiring the three-dimensional shape data and
A step of creating a welding path for forming each layer obtained by layering the shape of the three-dimensional shape data with the welding bead, and a laminating plan for defining welding conditions when forming the welding bead.
For the plurality of welding paths, a step of setting the inter-pass time from the end of the welding path to the start of the next welding path, performing heat transfer calculation in the inter-pass time, and calculating the inter-pass temperature.
A step of determining whether or not the inter-pass temperature falls within a preset inter-pass temperature range, adjusting the inter-pass time, and repeating the heat transfer calculation until the inter-pass temperature falls within the inter-pass temperature range. ,
Depending on the inter-pass time when the inter-pass temperature within the inter-pass temperature range is calculated and the welding pass time required for forming the welding bead in the welding pass, the laminated model is formed. The process of calculating the required molding time and
A step of repeatedly modifying the welding conditions in the lamination plan until the molding time becomes equal to or less than the upper limit value by comparing the molding time with a preset upper limit value.
A method of laminating a laminated model to execute. The method for planning the lamination of a laminated model according to claim 1, wherein the modification of the welding condition is to modify any of the welding speed, the number of passes, and the bead shape. The computer is
Based on the inter-pass time calculated after the heat transfer calculation is completed and the inter-pass temperature, a step of creating model shape data of the laminated model when heat shrinks,
A step of calculating the amount of surplus from the difference between the modeled object shape data and the modeled shape of the three-dimensional shape data, and
A step of estimating the cutting time, which is the processing time for the laminated model, from the surplus thickness,
And carry out
The laminating planning method for a laminated model according to claim 1 or 2, wherein the modification is performed by adding the cutting time to the modeling time. A method for manufacturing a laminated model, which manufactures the laminated model based on the laminated plan created by the method for planning the lamination of the laminated model according to any one of claims 1 to 3. It is a manufacturing apparatus for a laminated model that uses three-dimensional shape data of a laminated model to laminate weld beads on a base plate to form the laminated model.
An input unit for acquiring the three-dimensional shape data and
A lamination plan creation unit that creates a welding path for forming each layer obtained by layering the shape of the three-dimensional shape data with the welding bead, and a lamination plan that defines welding conditions when forming the welding bead.
For the plurality of welding paths, a temperature prediction unit that sets the inter-pass time from the end of the welding path to the start of the next welding path, performs heat transfer calculation in the inter-pass time, and calculates the inter-pass temperature.
It is determined whether or not the inter-pass temperature falls within the preset inter-pass temperature range, and the inter-pass time is changed and the heat transfer calculation is repeated until the inter-pass temperature falls within the inter-pass temperature range. Temperature control unit and
Depending on the inter-pass time when the inter-pass temperature within the inter-pass temperature range is calculated and the welding pass time required for forming the welding bead in the welding pass, the laminated model is formed. A modeling time estimation unit that calculates the required modeling time, and
A welding condition adjusting unit that repeatedly changes the welding conditions in the lamination plan until the molding time becomes equal to or less than the upper limit value by comparing the molding time with a preset upper limit value.
Equipment for manufacturing laminated objects.

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