JP2019044210A - Lamination molding apparatus and method for producing lamination molded object - Google Patents

Abstract

To provide a lamination molding apparatus and a method for producing a lamination molded object.SOLUTION: Provided is a lamination molding apparatus comprising: a chamber covering a molding region; a material layer formation device for forming a material layer every divided layers obtained by dividing a desired three-dimensional molded object to the molding region by a prescribed height; an irradiation device for irradiating the prescribed irradiation region of each material layer with a laser beam or an electron beam and performing sintering or melting to form a solidified layer; and a temperature adjustment device which, every time one or a plurality of solidified layers are newly formed, subjects an upper face layer(s) as the newly formed solidified layer(s) at least among the solidified layer(s), to temperature adjustment in the order of the first temperature, the second temperature and the first temperature, and, provided that the first temperature is defined as T1, the second temperature is defined as T2, the martensite transformation starting temperature of the solidified layer(s) is defined as Ms, and the transformation completion temperature thereof is defined as Mf, all of the relations in the following inequalities (1) to (3) are satisfied: T1≥Mf(1), T1>T2(2) and T2≤Ms (3).SELECTED DRAWING: Figure 10

Description

  The present invention relates to an additive manufacturing apparatus and a method for producing an additive.

Although there are multiple methods for metal additive manufacturing, for example, in powder sintering additive manufacturing method or powder fusion additive manufacturing method using laser light, vertical movement is possible in a sealed chamber filled with an inert gas. By forming a material layer made of metal material powder on a suitable modeling table, irradiating a predetermined portion of the material layer with a laser beam to repeat sintering or melting of the material powder at the irradiation position, a plurality of A solidified layer is laminated to form a desired three-dimensional structure (Patent Document 1). In addition, a modeling plate may be arrange | positioned on a modeling table, and the 1st-layer molten layer may be formed on a modeling plate.
Further, in the sheet laminating method, a material layer is formed using a plate-like metal sheet instead of metal material powder, and laser light is irradiated to a predetermined portion of the material layer to sinter or melt the metal sheet. A plurality of solidified layers are stacked to form a desired three-dimensional structure by repeating (see Patent Document 2).
In the above method, in order to form a solidified layer, an electron beam may be used instead of the laser beam (Patent Document 3).

Patent No. 5635657 gazette JP, 2015-098111, A Patent No. 6026688 gazette

  However, although the solidified layer formed by irradiating the material layer with laser light or electron beam has a very high temperature immediately after solidification, it dissipates heat to the inert gas atmosphere, the solidified layer already formed, and the formed plate. The temperature drops rapidly due to the heat treatment. At this time, the metal shrinks in volume because the coefficient of thermal expansion is positive. However, since the amount of contraction is limited by the close contact with the adjacent molten layer or the forming plate, it remains as a tensile stress. If this is repeated, the molded object will be deformed due to the tensile stress, and sometimes cracking will occur. Because of such limitations, it is difficult to obtain a shaped object of desired quality depending on the size and shape of the shaped object and the required accuracy in the metal additive manufacturing method.

  On the other hand, when the metal to be the material is a martensitic material such as carbon steel or martensitic stainless steel, the austenite phase is immediately after being formed as the solidified layer, but the predetermined temperature conditions and the like are satisfied. It is transformed into a martensitic phase by quenching. Since martensitic transformation involves volume expansion, compressive stress is generated.

  Therefore, the tensile stress due to metal contraction is reduced by the compressive stress due to the martensitic transformation by intentionally advancing the martensitic transformation every time one or more solidified layers are formed, and the residual stress of the shaped object Can be controlled.

  This invention is made in view of such a situation, and provides the manufacturing method of the lamination shaping apparatus which can suppress a deformation | transformation of a modeling thing by controlling the residual stress of a modeling thing, and a lamination modeling thing. is there.

According to the present invention, a chamber covering a modeling area, and a material layer forming apparatus for forming a material layer for each of a plurality of divided layers formed by dividing a desired three-dimensional modeling object at a predetermined height with respect to the modeling area An irradiation device for irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam to sinter or melt it to form a solidified layer, and each time one or more of the solidified layers is newly formed A temperature control device for controlling the temperature of an upper surface layer, which is at least a newly formed solidified layer, of the solidified layer in the order of a first temperature, a second temperature, and the first temperature, the first temperature being Where T1 is the second temperature, T2 is the second temperature, Ms is the martensitic transformation start temperature of the solidified layer, and Mf is the martensitic transformation end temperature of the solidified layer, all relationships of the following formulas (1) to (3) are It is filled,
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
An additive manufacturing apparatus is provided.

According to another aspect of the present invention, a recoating step of forming a material layer for each of a plurality of division layers formed by dividing a desired three-dimensional structure at a predetermined height with respect to a formation region; And a solidifying step of irradiating the laser irradiation area with a laser beam or an electron beam to sinter or melt it to form a solidified layer, and each time one or more of the solidified layers are newly formed, A temperature control step of controlling the temperature of the upper surface layer, which is at least a newly formed solidified layer, in the order of a first temperature, a second temperature, and the first temperature, wherein the first temperature is T1, the second Assuming that the temperature is T2, the martensitic transformation start temperature of the solidified layer is Ms, and the martensitic transformation end temperature of the solidified layer is Mf, all the relationships of the following formulas (1) to (3) are satisfied.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
There is provided a method of manufacturing a layered product.

  The laminate molding apparatus according to the present invention performs temperature control of the solidified layer, that is, the upper surface layer, each time one or more solidified layers are newly formed. According to this configuration, it is possible to reduce the tensile stress generated in the three-dimensional object, to suppress the deformation of the three-dimensional object, and to form the high-precision three-dimensional object without restriction of the size or shape of the three-dimensional object.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with one another.
Preferably, the material layer is made of carbon steel or martensitic stainless steel.
Preferably, the material layer is made of a mixed material containing at least one of a first metal and a second metal having a carbon content higher than that of the first metal or carbon.
Preferably, the apparatus further comprises a temperature sensor for measuring the temperature of the upper surface layer, and the temperature control device is feedback-controlled by the temperature measured by the temperature sensor.
Preferably, the apparatus further comprises a cutting device for cutting the solidified layer, wherein the temperature adjusting device adjusts the temperature of the upper surface layer from the first temperature to the second temperature, and then the temperature control device adjusts the temperature from the second temperature to the second temperature. Before adjusting the temperature to 1 temperature, cutting is performed on the end face of the solidified layer including the upper surface layer.
Preferably, the temperature of the upper surface layer is measured by a temperature sensor, and the temperature adjustment process is feedback controlled by the temperature measured by the temperature sensor.
Preferably, the method further includes a cutting step of cutting the solidified layer, and the cutting step adjusts the temperature of the upper surface layer from the second temperature to the first temperature after adjusting the temperature of the upper surface layer from the first temperature to the second temperature. Before that, cutting is performed on the end face of the solidified layer including the upper surface layer.
Preferably, the relationship of the following formulas (4) and (5) is further satisfied.
T1> Ms (4)
T2 <Mf (5)
Preferably, the relationship of the following formulas (4) and (6) is further satisfied.
T1> Ms (4)
T2 M Mf (6)
Preferably, the relationships of the following formulas (7) and (6) are further satisfied.
T1 ≦ Ms (7)
T2 M Mf (6)
Preferably, the relationship of the following formulas (7) and (5) is further satisfied.
T1 ≦ Ms (7)
T2 <Mf (5)

FIG. 1 is a schematic configuration view of a layered manufacturing apparatus according to an embodiment of the present invention. It is a perspective view of recoater head 11 concerning an embodiment of the present invention. It is the perspective view seen from another angle of the recoater head 11 which concerns on embodiment of this invention. It is a schematic block diagram of the laser irradiation apparatus 13 which concerns on embodiment of this invention. It is a schematic block diagram of an example of modeling table 5 provided with temperature control device 90 concerning an embodiment of the present invention. It is a schematic block diagram of the lamination-modeling apparatus provided with the temperature control apparatus 95 and the temperature sensor 99 of other embodiment of this invention. It is an explanatory view of a lamination modeling method using a lamination molding apparatus concerning an embodiment of the present invention. It is an explanatory view of a lamination modeling method using a lamination molding apparatus concerning an embodiment of the present invention. It is an explanatory view of a lamination modeling method using a lamination molding apparatus concerning an embodiment of the present invention. It is the schematic of the temperature change of the upper surface layer in the case of the pattern A of temperature control which concerns on embodiment of this invention. It is the schematic of the temperature change of the upper surface layer in the case of the pattern B of temperature control which concerns on embodiment of this invention. It is the schematic of the temperature change of the upper surface layer in the case of the pattern C of temperature control which concerns on embodiment of this invention. It is the schematic of the temperature change of the upper surface layer in the case of the pattern D of temperature control which concerns on embodiment of this invention. It is a figure which shows the result measured about distortion of the modeling thing by an example three-dimensionally. It is a figure shown about the distortion on xz plane in y = 0 of FIG. 14 of the three-dimensional object by an Example. It is a figure which shows the result measured about distortion of a modeling thing by a comparative example in three dimensions. It is a figure shown about the distortion on xz plane in y = 0 of Drawing 16 of a modeling thing by a comparative example.

  Hereinafter, embodiments of the present invention will be described using the drawings. The various features shown in the embodiments described below can be combined with one another.

  The laminate molding apparatus according to the embodiment of the present invention forms the material layer 8 made of material powder, irradiates the laser beam L to a predetermined place of the material layer 8 to sinter or melt the material powder at the irradiation position. It is a layered manufacturing apparatus which laminates a plurality of solidified layers and forms a desired three-dimensional shaped object by repeating repeating. The solidified layer is a generic term for a sintered layer and a molten layer. As shown in FIG. 1, the layered manufacturing apparatus of the present invention has a chamber 1 and a laser irradiation apparatus 13.

  The chamber 1 covers the required shaping area R and is filled with an inert gas of a predetermined concentration. In the chamber 1, a material layer forming device 3 is provided inside, and a protective window contamination preventing device 17 is provided on the upper surface portion. The material layer forming device 3 has a base 4 and a recoater head 11.

  The base 4 has a shaping region R in which the layered object is formed. In the modeling area R, a modeling table 5 is provided. The modeling table 5 can be driven by the modeling table drive mechanism 31 to move in the vertical direction (the arrow A direction in FIG. 1). At the time of use of the layered manufacturing apparatus, the modeling plate 7 is disposed on the modeling table 5, and the material layer 8 is formed thereon. In addition, the predetermined irradiation area is present in the modeling area R, and approximately coincides with the area surrounded by the outline shape of the desired three-dimensional structure.

  A powder holding wall 26 is provided around the shaping table 5. The powder holding space surrounded by the powder holding wall 26 and the shaping table 5 holds unsolidified material powder. Although not shown in FIG. 1, a powder discharging unit capable of discharging the material powder in the powder holding space may be provided below the powder holding wall 26. In such a case, the unsolidified material powder is discharged from the powder discharging unit by lowering the modeling table 5 after the completion of the lamination molding. The discharged material powder is guided to the shooter by the shooter guide and is stored in the bucket through the shooter.

  As shown in FIGS. 2 and 3, the recoater head 11 has a material storage portion 11 a, a material supply portion 11 b, and a material discharge portion 11 c.

  The material storage portion 11a stores the material powder. The material supply unit 11 b is provided on the upper surface of the material storage unit 11 a and serves as a receiving port for the material powder supplied from the material supply device (not shown) to the material storage unit 11 a. The material discharge part 11c is provided on the bottom of the material storage part 11a, and discharges the material powder in the material storage part 11a. In addition, the material discharge part 11c is a slit shape extended in the horizontal 1-axis direction (arrow C direction) orthogonal to the moving direction (arrow B direction) of the recoater head 11. As shown in FIG.

  Further, blades 11fb and 11rb are provided on both side surfaces of the recoater head 11, respectively. The blades 11fb and 11rb distribute the material powder. In other words, the blades 11 fb and 11 rb flatten the material powder discharged from the material discharge portion 11 c to form the material layer 8.

  The cutting device 50 has a processing head 57 provided with a spindle head 60. The processing head 57 moves the spindle head 60 to a desired position by a processing head drive mechanism (not shown).

  The spindle head 60 is configured such that a cutting tool such as an end mill (not shown) can be attached and rotated, and the surface or unnecessary portion of the solidified layer obtained by sintering or melting the material powder Cutting can be performed. The cutting tool is preferably a plurality of kinds of cutting tools, and the cutting tool to be used can be exchanged during shaping by an automatic tool changer (not shown).

  A protective window contamination prevention device 17 is provided on the upper surface of the chamber 1 so as to cover the protective window 1a. The protection window contamination prevention device 17 includes a cylindrical case 17 a and a cylindrical diffusion member 17 c disposed in the case 17 a. An inert gas supply space 17d is provided between the housing 17a and the diffusion member 17c. Further, an opening 17b is provided inside the diffusion member 17c on the bottom surface of the housing 17a. The diffusion member 17c is provided with a large number of pores 17e, and the clean inert gas supplied to the inert gas supply space 17d fills the clean chamber 17f through the pores 17e. Then, the clean inert gas filled in the clean chamber 17 f is jetted downward of the protective window pollution prevention device 17 through the opening 17 b.

  A laser irradiation device 13 is provided above the chamber 1 as the irradiation device. The laser irradiation apparatus 13 irradiates the laser beam L to a predetermined part of the material layer 8 formed on the modeling region R to sinter or melt the material powder at the irradiation position. Specifically, as shown in FIG. 4, the laser irradiation device 13 has a laser light source 42, biaxial galvano mirrors 43 a and 43 b, and a focus control unit 44. Each of the galvano mirrors 43a and 43b includes an actuator for rotating the galvano mirrors 43a and 43b.

  The laser light source 42 emits a laser beam L. Here, the laser beam L is a laser capable of sintering or melting the material powder, and is, for example, a CO 2 laser, a fiber laser, a YAG laser or the like.

  The focus control unit 44 condenses the laser light L output from the laser light source 42 and adjusts it to a desired spot diameter. The biaxial Galvano mirrors 43a and 43b two-dimensionally scan the laser light L output from the laser light source 42 in a controllable manner. The rotation angles of the galvano mirrors 43a and 43b are controlled in accordance with the magnitudes of rotation angle control signals input from a control device (not shown). According to this feature, the laser beam L can be irradiated to a desired position by changing the magnitudes of the rotation angle control signals input to the actuators of the galvano mirrors 43a and 43b.

  The laser beam L that has passed through the galvano mirrors 43a and 43b passes through the protective window 1a provided in the chamber 1 and is applied to the material layer 8 formed in the modeling region R. The protective window 1 a is formed of a material that can transmit the laser light L. For example, when the laser beam L is a fiber laser or a YAG laser, the protective window 1a can be made of quartz glass.

In the laminate molding apparatus according to the embodiment of the present invention, at least a newly formed solidified layer of the solidified layers is formed at a first temperature, a second temperature, and the like each time one or more solidified layers are newly formed. It has a temperature control apparatus which temperature-controls in order of 1st temperature. The first temperature and the second temperature are included in a temperature range that can be adjusted by the temperature controller, and the first temperature is T1, the second temperature is T2, the martensitic transformation start temperature of the solidified layer is Ms, and the marten of the solidified layer is Assuming that the site transformation end temperature is Mf, all the relationships of the following formulas (1) to (3) are satisfied.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
Also, in the following, a newly formed solidified layer, that is, a solidified layer that has been formed and has not been subjected to a temperature adjustment that has been performed once in a series of a first temperature, a second temperature, and a first temperature Called a layer. After sintering or melting, the upper surface layer before temperature control is in a state including an austenite phase, and at least a part is transformed into a martensitic phase by temperature control.

  The temperature control device may be configured to be able to adjust the temperature of the upper surface layer to the first temperature and the second temperature. In particular, the temperature control device includes at least one of a heater capable of heating the top surface layer and a cooler capable of cooling the top surface layer, preferably both.

  For example, the temperature adjustment device 90 is provided on the modeling table 5. As shown in FIG. 5, in one embodiment, the shaping table 5 including the temperature adjustment device 90 includes a top 5 a and three support plates 5 b, 5 c, and 5 d. A heater 92 capable of heating the top 5 a is disposed between the top 5 a and the support plate 5 b adjacent thereto. Moreover, the cooler 93 which can cool the top plate 5a is arrange | positioned between two support plate 5c, 5d of the lower side of the support plate 5b. The modeling table 5 is configured to be temperature adjustable by a heater 92 and a cooler 93, and the heater 92 and the cooler 93 constitute a temperature regulator 90. In the embodiment shown in FIG. 5, the cooler 93 is configured to sandwich the pipe material between the support plates 5c and 5d, but for example, a piping hole is formed in one or both of the support plates 5c and 5d. The cooler 93 can be configured to form a cooling pipe directly on the support plates 5c and 5d by forming and combining the support plates 5c and 5d. In addition, in order to prevent the thermal displacement of the modeling table drive mechanism 31, a constant temperature part maintained at a constant temperature may be provided between the temperature adjustment device 90 and the modeling table drive mechanism 31. By configuring the temperature adjustment device 90 as described above, the upper surface layer is brought to the desired temperature via the shaping plate 7 in contact with the top plate 5 a of the shaping table 5 set to the desired temperature and the lower solidified layer. It is possible to adjust. The material layer 8 is preferably preheated to a predetermined temperature for sintering or melting, but the temperature control device 90 also serves as a preheating device for the material layer 8. Specifically, the material layer 8 is kept at the first temperature by the temperature control device 9.

  Also, for example, as shown in FIG. 6, the layered manufacturing apparatus may be configured to include a temperature adjustment device 95 configured to adjust the temperature of the upper surface layer from the upper side thereof. The heater 97 of the temperature control device 95 is, for example, a halogen lamp. Further, the cooler 98 of the temperature adjustment device 95 may be, for example, a blower for blowing a cooling gas of the same kind as the inert gas or the like filled in the chamber 1 to the upper surface layer, or may be cooled by a Peltier element or the like. The cooling plate may be configured to be in contact with the top layer. According to such a temperature adjusting device 95, since the temperature of the upper surface layer can be directly adjusted, the temperature of the upper surface layer can be adjusted quickly even after forming the solidified layers of multiple layers.

  As described above, the temperature control device may be configured to be able to adjust the temperature of the upper surface layer to the first temperature and the second temperature, and various forms can be adopted. The temperature control devices 90 and 95 specifically shown above may be implemented in combination or only one. Or it may be another form.

  Further, as shown in FIG. 6, the layered manufacturing apparatus may have a temperature sensor 99 that measures the temperature of the upper surface layer, and the temperature adjustment devices 90 and 95 may be feedback-controlled. Such a configuration makes it possible to control the temperature of the top layer more accurately. A plurality of temperature sensors 99 may be provided. The temperature sensor 99 is, for example, an infrared temperature sensor.

  The chamber 1 is supplied with an inert gas of a predetermined concentration, and discharges the inert gas containing fumes generated when the material layer 8 is sintered or melted. Specifically, a fume collector 19 is connected to the chamber 1 via an inert gas supply device 15 and duct boxes 21 and 23. The inert gas supply device 15 has a function of supplying an inert gas, and is, for example, a device provided with a membrane type nitrogen separator that takes out nitrogen gas from ambient air. The inert gas supply device 15 supplies inert gas from a supply port provided in the chamber 1 and fills the chamber 1 with inert gas of a predetermined concentration. Further, the inert gas containing a large amount of fumes exhausted from the exhaust port of the chamber 1 is sent to the fume collector 19 and removed from the fumes and returned to the chamber 1. In the present specification, an inert gas is a gas that does not substantially react with the material powder, and an appropriate gas is selected from nitrogen gas, argon gas, helium gas, etc. according to the type of material powder. Ru.

  Here, each process in the manufacturing method of the laminate-molded article which concerns on one Embodiment of this invention is demonstrated using FIGS. 7-9. 7 to 9, the components shown in FIG. 1 are partially omitted in consideration of visibility. Further, in the following, the step of forming the material layer 8 for each of a plurality of division layers formed by dividing a desired three-dimensional structure at a predetermined height with respect to the formation region R is a recoating step, predetermined irradiation of the material layer 8 The step of irradiating the region with laser light L to sinter or melt it to form a solidified layer is a solidifying step, and at least the upper surface layer of the solidified layer is temperature-controlled in the order of a first temperature, a second temperature, and a first temperature. Is called a temperature control process.

  First, the first recoating step is performed. As shown in FIG. 7, the shaping plate 7 is placed on the shaping table 5, and the height of the shaping table 5 is adjusted to an appropriate position. In this state, the recoater head 11 in which the material powder is filled in the material storage portion 11a is moved from the left side to the right side of the modeling area R in the direction of arrow B in FIG. The material layer 8 of

  Next, a first solidification step is performed. A predetermined portion in the material layer 8 is irradiated with the laser light L to sinter or melt the laser irradiation position of the material layer 8 to obtain a first solidified layer 81 f as shown in FIG. Here, the temperature of the first solidified layer 81 f is adjusted to the first temperature.

  Next, as the second recoating step, the height of the shaping table 5 is lowered by a predetermined thickness (one layer) of the material powder layer 8, and the recoater head 11 is moved from the right side to the left side of the shaping area R. The second material layer 8 is formed on the solidified layer 81 f.

  Next, as shown in FIG. 9, as a second solidification step, laser light L is irradiated to a predetermined site in the material powder layer 8 to sinter or melt the laser irradiation position of the material layer 8. A solidified layer 82f is obtained. Here, the temperature of the second solidified layer 82f is adjusted to the first temperature.

  By repeating the above steps, the third and subsequent solidified layers are formed. When a predetermined number of solidified layers are formed, a temperature control process is performed by the temperature control device. First, the upper surface layer held at the first temperature is cooled, and the temperature is adjusted to the second temperature. Next, the temperature of the upper surface layer adjusted to the second temperature is raised, and the temperature is adjusted again to the first temperature.

  In the layered manufacturing apparatus provided with the cutting device 50 as in this embodiment, the cutting surface mounted on the spindle head 60 cuts the end face of the solidified layer every time a predetermined number of solidified layers are formed. You may implement the cutting process which processes. The cutting process is performed, for example, every time the solidified layer is laminated to a predetermined thickness of 0.4 mm to 1 mm. Preferably, cutting is performed on the upper surface layer temperature-controlled to the second temperature. In other words, with respect to the end face of the solidified layer including the upper surface layer, the temperature adjusting device temperature-regulates the upper surface layer from the first temperature to the second temperature until the temperature adjustment from the second temperature to the first temperature. Make a cut. Since cutting can be performed on the upper surface layer after martensitic transformation has occurred and the dimensions are stabilized, cutting can be performed with higher accuracy. In addition, spatter generated during sintering or melting may adhere to the surface of the solidified layer to form a projection, but when the recoater head 11 collides with the projection during the recoating step, the projection is removed. For this purpose, the upper surface of the uppermost solidified layer may be cut.

  Such recoating step, solidification step and temperature adjustment step, and preferably the cutting step are repeated to form a desired three-dimensional structure. The temperature control step may be carried out each time a solidified layer is formed, or may be carried out each time a plurality of layers are formed, or when a cutting step is carried out, it may be carried out every cutting step. Good. Further, the cycle of the temperature control process may be set variably according to the shape of the object. For example, although the temperature control step is usually performed every 5 mm of the solidified layer, the temperature control step may be interrupted immediately before forming the solidified layer having a fragile shape.

  By the temperature adjustment process as described above, it is possible to reduce the tensile stress resulting from the contraction due to the cooling of the solidified layer, and to suppress the deformation of the shaped article. That is, in the metal material in which martensitic transformation occurs, the volume expands at the time of martensitic transformation, and the volume contraction at the time of cooling is relaxed. Here, the martensitic transformation occurs when the solidified layer is rapidly cooled from the martensitic transformation start temperature (Ms) to the martensitic transformation end temperature (Mf). That is, martensitic transformation occurs in the range of Ms or less and Ms or more.

  Further, this transformation amount (= expansion amount) can be controlled by the relationship between the first temperature, the second temperature, the martensitic transformation end temperature, and the martensitic transformation start temperature. That is, the residual stress of a shaped article can be controlled by their temperature relationship. Here, four temperature control patterns (A to D) can be mentioned as a representative example of the control method of the residual stress. In addition, although the same pattern may be applied to all solidified layers, different patterns may be individually applied to each solidified layer.

<Pattern A>
In the pattern A, both the first temperature and the second temperature are not included in the temperature zone where the martensitic transformation occurs. That is, all the following formulas (1) to (5) are satisfied. Moreover, the schematic of the temperature change of the upper surface layer of the pattern A is shown in FIG.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
T1> Ms (4)
T2 <Mf (5)
In the pattern A, temperature control is facilitated because the upper limit of the first temperature and the lower limit of the second temperature are not limited as long as the temperature adjustment by the temperature adjustment device is possible. In addition, since the martensitic transformation occurs in the entire range of the temperature range in which the martensitic transformation occurs, the reproducibility is high. This control method is suitable for a material in which the amount of expansion due to martensitic transformation is equal to or less than the amount of contraction at the time of shaping.

<Pattern B>
In the pattern B, only the second temperature is included in the temperature range in which the martensitic transformation occurs. That is, the following formulas (1) to (4) and (6) are all satisfied. Moreover, the schematic of the temperature change of the upper surface layer of the pattern B is shown in FIG.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
T1> Ms (4)
T2 M Mf (6)
In the pattern B, it is not necessary to consider the influence of the temperature rise of the solidified layer due to the irradiation of the laser light L, and the shaping can be progressed in a state in which the residual stress is suppressed. Can be generated. By leaving an appropriate compressive stress in the shaped article, the occurrence of cracking can be suppressed. This control method is suitable for a material in which the amount of expansion due to martensitic transformation is sufficiently larger than the amount of contraction at the time of shaping.

<Pattern C>
In the pattern C, both the first temperature and the second temperature are included in the temperature range where the martensitic transformation occurs. That is, the following formulas (1) to (3) and (6) to (7) are all satisfied. Further, a schematic view of the temperature change of the upper surface layer of the pattern C is shown in FIG.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
T1 ≦ Ms (7)
T2 M Mf (6)
In the pattern C, when accurate temperature control can be performed, it is possible to control residual stress during formation and after formation is completed and the temperature is lowered. This control method is suitable for a material in which the amount of expansion due to martensitic transformation is sufficiently larger than the amount of contraction at the time of shaping.

<Pattern D>
In the pattern C, only the first temperature is included in the temperature range in which the martensitic transformation occurs. That is, the following formulas (1) to (3), (5), and (7) are all satisfied. Moreover, the schematic of the temperature change of the upper surface layer of the pattern D is shown in FIG.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
T1 ≦ Ms (7)
T2 <Mf (5)
In the pattern D, although there is an effect of the temperature rise of the solidified layer due to the irradiation of the laser light L, the residual stress during shaping and the residual stress after completion of shaping substantially coincide with each other, and management is easy. In particular, as described above, in the case of carrying out the cutting step of cutting the upper surface layer adjusted to the second temperature, the shaped object can be finished with higher accuracy, which is preferable. This control method is suitable for a material in which the amount of expansion due to martensitic transformation is sufficiently larger than the amount of contraction at the time of shaping.

  A material powder that can be used in the method of manufacturing a laminate of a metal laminate according to an embodiment of the present invention is a powder of a metal material that undergoes martensitic transformation, such as carbon steel or martensitic stainless steel. The shape of the material powder is, for example, a spherical shape with an average particle diameter of 20 μm.

  In addition, the temperature control patterns described above are limited in applicable materials. For example, when performing the temperature control of the pattern A described above, it is necessary to include at least a martensitic transformation start temperature and a martensitic transformation end temperature within a range where temperature control by the temperature control device is possible. Materials do not necessarily meet that condition. On the other hand, it is known that the martensitic transformation start temperature and the martensitic transformation end temperature rise and fall depending on the carbon content of the material. Therefore, by adjusting the carbon content of the material, the shaping method using the martensitic transformation of the present invention can be applied to various materials.

  As a method of adjusting the carbon content of the material, for example, a plurality of materials may be mixed. Specifically, a mixed material having a desired martensitic transformation start temperature or a martensitic transformation end temperature is formed by mixing at least one of a metal having a relatively high carbon content and carbon with a certain metal. May be

  The lamination molding apparatus according to the embodiment of the present invention is a lamination molding apparatus according to a powder sintering lamination molding system or a powder fusion lamination molding system, but may be a lamination molding apparatus according to a sheet lamination system. That is, instead of the material powder, a plate-like metal sheet may be used to form a material layer, and laser light may be irradiated to a predetermined portion of the material layer to repeat melting the metal sheet. Moreover, although the laser irradiation apparatus 13 which irradiates the laser beam L is used as an irradiation apparatus for formation of a solidified layer in this embodiment, you may use the electron beam irradiation apparatus which irradiates an electron beam.

  While the embodiments of the present invention and the modifications thereof have been described, these are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

  Hereinafter, the detailed contents will be described using examples, but the present invention is not limited to the following examples.

Material powder: SUS420J2 (Carbon content: <0.44 wt%, Ms: approx. 100 ° C, Mf: approx. 0 ° C) with an average particle size of 20 μm, under various temperature conditions, 125 x 125 x 15 mm (longitudinal On the shaping plate 7 of x width x thickness), layered formation of a 80 x 80 x 35 mm (length x width x thickness) shaped object was performed.
<Example>
First, the temperature of the modeling table 5 was adjusted to 70 ° C. by the temperature adjusting device 90. Subsequently, the material powder is uniformly distributed on the shaping table 5 by the recoater head 11 to form the material layer 8, and the predetermined portion of the material layer 8 is irradiated with the laser light L for about 4 minutes to be a material The solidifying step of sintering the powder was repeated to form an upper surface layer of 5 mm in thickness formed by a plurality of solidified layers. Thereafter, the temperature of the shaping table 5 kept at about 70 ° C. was lowered to 29 ° C. After the temperature of the upper surface layer was lowered to 29 ° C., the temperature of the shaping table 5 was raised to 70 ° C. That is, the temperature adjustment step corresponding to the pattern D was performed. Thereafter, the same process was repeated six times to obtain a shaped article of 80 × 80 × 35 mm (length × width × thickness). The state of residual stress was confirmed by measuring the state of warpage of the back surface of the formed plate 7 (the surface opposite to the surface on which the formed object was formed) of the obtained formed object. As a result, as shown in FIG. 14 and FIG. 15, the residual stress was suppressed.

Comparative Example
The temperature of the shaping table 5 was kept substantially constant at 24 ° C., and the recoating step and the solidifying step were repeated without performing the temperature adjustment step to obtain a shaped article of 80 × 80 × 35 mm (length × width × thickness). As a result of confirming the state of the formed article as in the example, as shown in FIGS. 16 and 17, the strain was large and the tensile stress was large. In addition, a big crack generate | occur | produced in the boundary with the modeling plate 7, and the crack was confirmed by the modeling thing.

1: Chamber 1a: Protective window 3: Material layer forming device 4: Base 5: Modeling table 5a: Top plate 5b: Support plate 5c: Support plate 5d: Support plate 7: Modeling plate 8: Material layer 11: Recoater head 11a: material storage portion 11b: material supply portion 11c: material discharge portion 11fb: blade 11rb: blade 13: laser irradiation device 15: inert gas supply device 17: protection window contamination prevention device 17a: housing 17b: opening 17c: Diffusion member 17d: inert gas supply space 17e: pore 17f: clean chamber 19: fume collector 21: duct box 23: duct box 26: powder holding wall 31: modeling table drive mechanism 42: laser light source 43a: galvano mirror 43b : Galvano mirror 44: Focus control unit 50: Cutting device 57: Processing head 60: spindle head 81f: solidified layer 82f: solidified layer 90: temperature regulator 92: heater 93: cooler 95: temperature regulator 97: heater 98: cooler 99: temperature sensor L: laser beam R: Modeling area

By the temperature adjustment process as described above, it is possible to reduce the tensile stress resulting from the contraction due to the cooling of the solidified layer, and to suppress the deformation of the shaped article. That is, in the metal material in which martensitic transformation occurs, the volume expands at the time of martensitic transformation, and the volume contraction at the time of cooling is relaxed . In here, martensitic transformation occurs in the martensite transformation start temperature or less and a range of more than martensitic transformation finish temperature.

<Pattern D>
In the pattern D , only the first temperature is included in the temperature range in which the martensitic transformation occurs. That is, the following formulas (1) to (3), (5), and (7) are all satisfied. Moreover, the schematic of the temperature change of the upper surface layer of the pattern D is shown in FIG.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
T1 ≦ Ms (7)
T2 <Mf (5)
In the pattern D, although there is an effect of the temperature rise of the solidified layer due to the irradiation of the laser light L, the residual stress during shaping and the residual stress after completion of shaping substantially coincide with each other, and management is easy. In particular, as described above, in the case of carrying out the cutting step of cutting the upper surface layer adjusted to the second temperature, the shaped object can be finished with higher accuracy, which is preferable. This control method is suitable for a material in which the amount of expansion due to martensitic transformation is sufficiently larger than the amount of contraction at the time of shaping.

According to the present invention, a chamber covering a modeling area, and a material layer forming apparatus for forming a material layer for each of a plurality of divided layers formed by dividing a desired three-dimensional modeling object at a predetermined height with respect to the modeling area An irradiation device for irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam to sinter or melt it to form a solidified layer, and each time one or more of the solidified layers is newly formed , and a temperature adjustment device for adjusting the temperature at least newly formed the a solidified layer top layer a first temperature, a second temperature, the order of the first temperature of the solidified layer, the first Assuming that the temperature is T1, the second temperature is T2, the martensitic transformation start temperature of the solidified layer is Ms, and the martensitic transformation end temperature of the solidified layer is Mf, the relationship of the following formulas (1) to (3) is All satisfied,
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
An additive manufacturing apparatus is provided.

According to another aspect of the present invention, a recoating step of forming a material layer for each of a plurality of division layers formed by dividing a desired three-dimensional structure at a predetermined height with respect to a formation region; And a solidifying step of irradiating the laser irradiation area with a laser beam or an electron beam to sinter or melt it to form a solidified layer, and each time one or more of the solidified layers are newly formed, at least newly formed the a solidified layer top layer a first temperature, a second temperature, and a temperature adjustment step of adjusting the temperature in the order of the first temperature, the first temperature T1, the first Assuming that two temperatures are T2, the martensitic transformation start temperature of the solidified layer is Ms, and the martensitic transformation end temperature of the solidified layer is Mf, all the relationships of the following formulas (1) to (3) are satisfied.
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
There is provided a method of manufacturing a layered product.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with one another.
Preferably, the material layer is made of carbon steel or martensitic stainless steel.
Preferably, the material layer is made of a mixed material containing at least one of a first metal and a second metal having a carbon content higher than that of the first metal or carbon.
Preferably, further comprising a temperature sensor for measuring the temperature of the top surface layer, the temperature adjustment device is feedback-controlled by the temperature measured by the temperature sensor.
Preferably, the apparatus further comprises a cutting device for cutting the solidified layer, wherein the temperature adjusting device adjusts the temperature of the upper surface layer from the first temperature to the second temperature, and then the temperature control device adjusts the temperature from the second temperature to the second temperature. Before adjusting the temperature to 1 temperature, cutting is performed on the end face of the solidified layer including the upper surface layer.
Preferably, the temperature of the upper surface layer is measured by a temperature sensor, and the temperature adjustment process is feedback controlled by the temperature measured by the temperature sensor.
Preferably, the method further includes a cutting step of cutting the solidified layer, and the cutting step adjusts the temperature of the upper surface layer from the second temperature to the first temperature after adjusting the temperature of the upper surface layer from the first temperature to the second temperature. Before that, cutting is performed on the end face of the solidified layer including the upper surface layer.
Preferably, the relationship of the following formulas (4) and (5) is further satisfied.
T1> Ms (4)
T2 <Mf (5)
Preferably, the relationship of the following formulas (4) and (6) is further satisfied.
T1> Ms (4)
T2 M Mf (6)
Preferably, the relationships of the following formulas (7) and (6) are further satisfied.
T1 ≦ Ms (7)
T2 M Mf (6)
Preferably, the relationship of the following formulas (7) and (5) is further satisfied.
T1 ≦ Ms (7)
T2 <Mf (5)

For example, the temperature adjustment device 90 is provided on the modeling table 5. As shown in FIG. 5, in one embodiment, the shaping table 5 including the temperature adjustment device 90 includes a top 5 a and three support plates 5 b, 5 c, and 5 d. A heater 92 capable of heating the top 5 a is disposed between the top 5 a and the support plate 5 b adjacent thereto. Moreover, the cooler 93 which can cool the top plate 5a is arrange | positioned between two support plate 5c, 5d of the lower side of the support plate 5b. Molding table 5 is configured to be temperature adjusted by the heater 92 and the cooler 93, the heater 92 and the cooler 93 constitute the temperature adjusting device 90. In the embodiment shown in FIG. 5, the cooler 93 is configured to sandwich the pipe material between the support plates 5c and 5d, but for example, a piping hole is formed in one or both of the support plates 5c and 5d. The cooler 93 can be configured to form a cooling pipe directly on the support plates 5c and 5d by forming and combining the support plates 5c and 5d. In addition, in order to prevent the thermal displacement of the modeling table drive mechanism 31, a constant temperature part maintained at a constant temperature may be provided between the temperature adjustment device 90 and the modeling table drive mechanism 31. By configuring the temperature adjustment device 90 as described above, the upper surface layer is brought to the desired temperature via the shaping plate 7 in contact with the top plate 5 a of the shaping table 5 set to the desired temperature and the lower solidified layer. It is possible to adjust. The material layer 8 is preferably preheated to a predetermined temperature for sintering or melting, but the temperature control device 90 also serves as a preheating device for the material layer 8. Specifically, the material layer 8 is kept at the first temperature by the temperature control device 9.

Also, for example, as shown in FIG. 6, the layered manufacturing apparatus may be configured to include a temperature adjustment device 95 configured to adjust the temperature of the upper surface layer from the upper side thereof. The heater 97 of the temperature control device 95 is, for example, a halogen lamp. Further, the cooler 98 of the temperature adjustment device 95 may be, for example, a blower for blowing a cooling gas of the same kind as the inert gas or the like filled in the chamber 1 to the upper surface layer, or may be cooled by a Peltier element or the like. The cooling plate may be configured to be in contact with the top layer. According to such a temperature adjusting device 95, directly for the top layer can be temperature adjusted, it is possible to perform temperature adjustment of rapidly top layer even after the formation of the solidified layer of the multiple layer.

Such recoating step, solidification step and temperature adjustment step, and preferably the cutting step are repeated to form a desired three-dimensional structure. Incidentally, the temperature adjustment step may be performed for each to form a solidified layer 1 layer may be performed every time a plurality of layers formed, when carrying out the cutting step is performed for each cutting step It is also good. The period of temperature adjustment step according to the shape of the shaped object may be set variably. For example, although in the normal perform temperature adjustment process for each of 5mm stacked solidified layers, it may be to interrupt the temperature control process is immediately before forming the solidified layer of the fragile shape.

Claims (18)

A chamber covering the modeling area,
A material layer forming apparatus for forming a material layer for each of a plurality of division layers formed by dividing a desired three-dimensional structure at a predetermined height with respect to the formation area;
An irradiation device for irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam to sinter or melt it to form a solidified layer;
Each time one or more of the solidified layers are newly formed, at least a newly formed upper surface layer of the solidified layers, which is the solidified layer, is provided with a first temperature, a second temperature, and the first temperature. A temperature control device that adjusts the temperature in order;
Assuming that the first temperature is T1, the second temperature is T2, the martensitic transformation start temperature of the solidified layer is Ms, and the martensitic transformation end temperature of the solidified layer is Mf, the following formulas (1) to (3) All relationships of are satisfied,
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
Stacking device.   The layered manufacturing apparatus according to claim 1, wherein the material layer is made of carbon steel or martensitic stainless steel.   The laminate according to claim 1 or 2, wherein the material layer is made of a mixed material containing at least one of a first metal and a second metal having a carbon content higher than that of the first metal or carbon. Modeling device. It further comprises a temperature sensor for measuring the temperature of the upper surface layer,
The layered manufacturing apparatus according to any one of claims 1 to 3, wherein the temperature control device is feedback-controlled by the temperature measured by the temperature sensor. The apparatus further comprises a cutting device for cutting the solidified layer,
The cutting device includes the upper surface layer before the temperature adjustment device temperature-regulates the upper surface layer from the first temperature to the second temperature and then adjusts the temperature from the second temperature to the first temperature. The layered manufacturing apparatus according to any one of claims 1 to 4, wherein the end face of the solidified layer is cut. Further satisfying the relationship of the following equations (4) and (5),
T1> Ms (4)
T2 <Mf (5)
The layered manufacturing apparatus according to any one of claims 1 to 5. Further satisfying the relationship of the following equations (4) and (6),
T1> Ms (4)
T2 M Mf (6)
The layered manufacturing apparatus according to any one of claims 1 to 5. Further satisfying the relationship of the following equations (7) and (6),
T1 ≦ Ms (7)
T2 M Mf (6)
The layered manufacturing apparatus according to any one of claims 1 to 5. Further satisfying the relationship of the following formulas (7) and (5),
T1 ≦ Ms (7)
T2 <Mf (5)
The layered manufacturing apparatus according to any one of claims 1 to 5. A recoating step of forming a material layer for each of a plurality of division layers formed by dividing a desired three-dimensional structure at a predetermined height with respect to a formation area;
A solidifying step of irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam to sinter or melt it to form a solidified layer;
Each time one or more of the solidified layers are newly formed, at least a newly formed upper surface layer of the solidified layers, which is the solidified layer, is provided with a first temperature, a second temperature, and the first temperature. Temperature control step of adjusting temperature in order;
Assuming that the first temperature is T1, the second temperature is T2, the martensitic transformation start temperature of the solidified layer is Ms, and the martensitic transformation end temperature of the solidified layer is Mf, the following formulas (1) to (3) All relationships of are satisfied,
T1 M Mf (1)
T1> T2 (2)
T2 ≦ Ms (3)
A method of manufacturing a layered product.   The method of manufacturing a laminate-molded product according to claim 10, wherein the material layer is made of carbon steel or martensitic stainless steel.   The lamination according to claim 10 or 11, wherein the material layer is made of a mixed material containing at least one of a first metal and a second metal having a carbon content higher than that of the first metal or carbon. Method of manufacturing a shaped object. The temperature of the top layer is measured by a temperature sensor,
The method for manufacturing a laminate-molded article according to any one of claims 10 to 12, wherein the temperature adjustment step is feedback-controlled by the temperature measured by the temperature sensor. The method further comprises a cutting step of cutting the solidified layer,
In the cutting step, after adjusting the temperature of the upper surface layer from the first temperature to the second temperature and before adjusting the temperature of the second temperature to the first temperature, the end surface of the solidified layer including the upper surface layer The manufacturing method of the laminate-molded article according to any one of claims 10 to 13, wherein cutting is performed. Further satisfying the relationship of the following equations (4) and (5),
T1> Ms (4)
T2 <Mf (5)
The manufacturing method of the laminate-molded article according to claim 10. Further satisfying the relationship of the following equations (4) and (6),
T1> Ms (4)
T2 M Mf (6)
The manufacturing method of the laminate-molded article according to claim 10. Further satisfying the relationship of the following equations (7) and (6),
T1 ≦ Ms (7)
T2 M Mf (6)
The manufacturing method of the laminate-molded article according to claim 10. Further satisfying the relationship of the following formulas (7) and (5),
T1 ≦ Ms (7)
T2 <Mf (5)
The manufacturing method of the laminate-molded article according to claim 10.