JP6283053B2 - Additive manufacturing equipment - Google Patents

Description

  The present invention relates to an additive manufacturing apparatus.

  In the layered manufacturing method using laser light, a very thin material powder layer is formed on a modeling table movable in the vertical direction in a sealed chamber filled with an inert gas. By repeatedly irradiating the portion with laser light to sinter the material powder at the irradiation position, a desired three-dimensional shape made of a sintered body formed by laminating a plurality of sintered layers is formed. In addition, it is preferable to use a cutting tool such as an end mill that can move in the vertical and horizontal directions to machine the surface of the sintered body obtained by sintering the material powder and unnecessary parts during the modeling of the modeled object. Processing may be performed. A desired layered object is formed through a combination and repetition of such steps.

  There are many heat sources in an additive manufacturing apparatus for performing such additive manufacturing, and thermal displacement occurs in various members due to heat from the heat source. In particular, the laser beam irradiation unit that irradiates a laser beam to a predetermined position of the material powder layer is provided at a position away from the material powder layer on the modeling table as compared to a cutting device including a cutting tool. It is susceptible to misalignment due to thermal displacement. Therefore, in order to maintain the accuracy of additive manufacturing, it is necessary to periodically correct the irradiation position of the laser light from the laser light irradiation unit.

  In Patent Document 1, in order to correct such a deviation, a reference mark is set at a position adjacent to the modeling area, and the positional deviation is detected by measuring the reference mark before and during the modeling through the scanning optical system. Correction is being performed. In addition, to measure the fiducial mark, the imaging unit is moved and inserted into the optical path using a moving mechanism at the time of measurement, or the half mirror is always placed in the optical path and the light is imaged with the half mirror. The structure which guides to the part is adopted.

Japanese Patent No. 4130813

  However, the method of Patent Document 1 has a problem that the correction accuracy decreases due to the thermal displacement of the moving mechanism itself when the moving mechanism is used. In the method of inserting the half mirror, the laser beam is attenuated by the half mirror. There are problems such as. Furthermore, since the position of the reference mark is away from the imaging unit, it is difficult to perform high-precision correction.

  This invention is made | formed in view of such a situation, and provides the additive manufacturing apparatus which can form a high quality molded article.

  According to the present invention, a laser beam is applied to sinter material powder in a chamber that covers the modeling region and is filled with an inert gas, and an irradiation region on the material powder layer formed on the modeling region. A laser beam irradiation unit, a cutting device for moving a cutting tool for cutting a sintered layer obtained by sintering the material powder in the vertical and horizontal directions in the chamber, and the laser beam or the same beam as the laser beam A light detection unit that detects an irradiation position of correction light composed of coaxial light having an axis, and a correction unit that corrects the irradiation position of the laser light based on the irradiation position of the correction light detected by the light detection unit; And the light detection unit is provided in the cutting device.

  In the present invention, unlike a conventional technique such as Patent Document 1, a light detection unit provided in a cutting apparatus is used. Therefore, by correcting the irradiation position of the laser beam, the planar coordinate system and the cutting tool related to the laser beam irradiation are corrected. Correspondence with a plane coordinate system related to position control can also be performed, and cutting accuracy can be improved. In addition, since the light detection unit is configured to be movable, it is possible to perform correction at a position where the measurement error is small, and it is possible to realize correction with higher accuracy. As described above, according to the present invention, a high-quality model can be formed.

  Hereinafter, various embodiments of the present invention will be exemplified. The following embodiments can be combined with each other.

  Preferably, the apparatus further includes a recoater head that forms the material powder layer by spreading the material powder on the modeling region while moving in the chamber, and the cutting device includes a predetermined part of the recoater head. With the movement in one direction or after completion of the movement, the light detection unit is moved from the retracted position to the measurement position, and the correction unit is detected by the light detection unit in a state where the light detection unit is at the measurement position. The laser light irradiation position is corrected based on the correction light irradiation position.

  Preferably, the light detection unit is arranged on any one coordinate axis of a planar coordinate system related to position control of the cutting tool.

  Preferably, the cutting apparatus moves the light detection unit so as to detect laser light irradiated to two points that are equidistant from an origin of a planar coordinate system related to position control of the laser light.

  Preferably, the light detection unit includes a plurality of light detection units including first and second light detection units, and the correction unit is an irradiation position of the correction light detected by the first and second light detection units. The first and second light detectors are arranged equidistantly from one of the coordinate axes of the planar coordinate system related to the position control of the cutting tool. The

  Preferably, the cutting device is configured so that the first and second light detection units respectively detect laser beams irradiated to two points that are equidistant from an origin of a planar coordinate system related to position control of the laser light. Move the light detector.

It is a schematic block diagram of the additive manufacturing apparatus which concerns on 1st and 2nd embodiment of this invention. It is a perspective view of the powder layer forming apparatus 3 and the laser beam irradiation part 13 which concern on 1st and 2nd embodiment of this invention. It is a perspective view of the recoater head 11 concerning the 1st and 2nd embodiment of the present invention. It is the perspective view seen from another angle of the recoater head 11 concerning the 1st and 2nd embodiments of the present invention. FIG. 5 is a schematic diagram illustrating a light detection unit 41 provided on a machining head 57 in the PP cross section in FIG. 1 according to the first embodiment of the present invention. It is explanatory drawing of the additive manufacturing method using the additive manufacturing apparatus which concerns on 1st and 2nd embodiment of this invention. It is explanatory drawing of the additive manufacturing method using the additive manufacturing apparatus which concerns on 1st and 2nd embodiment of this invention. It is explanatory drawing of the additive manufacturing method using the additive manufacturing apparatus which concerns on 1st and 2nd embodiment of this invention. It is explanatory drawing of the additive manufacturing method using the additive manufacturing apparatus which concerns on 1st and 2nd embodiment of this invention. FIG. 4 is a schematic diagram illustrating a relationship between a first target irradiation position and a second target irradiation position according to the first embodiment of the present invention. FIG. 6 is a schematic diagram illustrating a relationship between a target irradiation position and an actual irradiation position according to the first and second embodiments of the present invention. FIG. 5 is a schematic diagram showing a first light detection unit 41 a and a second light detection unit 41 b provided on a machining head 57 in the PP cross section in FIG. 1 according to the second embodiment of the present invention. FIG. 10 is a schematic diagram illustrating a relationship between a first target irradiation position and a second target irradiation position according to the second embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various characteristic items shown in the following embodiments can be combined with each other.

1. First Embodiment As shown in FIG. 1, an additive manufacturing apparatus according to a first embodiment of the present invention includes a chamber 1 and a laser beam irradiation unit 13.

  The chamber 1 covers a required modeling region R and is filled with an inert gas having a predetermined concentration. The chamber 1 is provided with a powder layer forming device 3 inside, and a fume diffusing device 17 is provided on the upper surface. The powder layer forming apparatus 3 includes a base table 4 and a recoater head 11.

  The base 4 has a modeling region R where a layered product is formed. In the modeling region R, a modeling table 5 is provided. The modeling table 5 is driven by the modeling table drive mechanism 31 and can move in the vertical direction (the direction of arrow A in FIG. 1). When the additive manufacturing apparatus is used, the modeling plate 7 is disposed on the modeling table 5, and the material powder layer 8 is formed thereon. In addition, the predetermined irradiation region exists in the modeling region R and approximately matches the region surrounded by the contour shape of the desired three-dimensional structure.

  A powder holding wall 26 is provided around the modeling table 5. In the powder holding space surrounded by the powder holding wall 26 and the modeling table 5, unsintered material powder is held. Although not shown in FIG. 1, a powder discharge 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 unsintered material powder is discharged from the powder discharge section by lowering the modeling table 5 after the completion of the layered modeling. The discharged material powder is guided to the shooter by the shooter guide and is accommodated in the bucket through the shooter.

  As shown in FIGS. 2 to 4, the recoater head 11 includes a material storage portion 11 a, a material supply portion 11 b, and a material discharge portion 11 c.

  The material accommodating part 11a accommodates material powder. The material powder is, for example, metal powder (eg, iron powder), for example, a spherical shape having an average particle diameter of 20 μm. The material supply unit 11b is provided on the upper surface of the material storage unit 11a, and serves as a receiving port for the material powder supplied from the material supply device (not shown) to the material storage unit 11a. The material discharge part 11c is provided in the bottom face of the material storage part 11a, and discharges the material powder in the material storage part 11a. In addition, the material discharge | emission part 11c is a slit shape extended in the horizontal uniaxial direction (arrow C direction) orthogonal to the moving direction (arrow B direction) of the recoater head 11. FIG.

  Also, blades 11fb and 11rb, a recoater head supply port 11fs, and a recoater head discharge port 11rs are provided on both side surfaces of the recoater head 11. The blades 11fb and 11rb distribute the material powder. In other words, the blades 11fb and 11rb flatten the material powder discharged from the material discharge portion 11c to form the material powder layer 8. The recoater head supply port 11fs and the recoater head discharge port 11rs are respectively provided along a horizontal one-axis direction (arrow C direction) orthogonal to the moving direction of the recoater head 11 (arrow B direction). Supply and discharge (details will be described later). In this specification, the “inert gas” is a gas that does not substantially react with the material powder, and examples thereof include nitrogen gas, argon gas, and helium gas.

  The cutting device 50 includes a machining head 57 provided with a spindle head 60 and a light detection unit 41. The processing head 57 moves the spindle head 60 and the light detection unit 41 to desired positions in the horizontal and vertical directions so that they can be controlled by a processing head drive mechanism (not shown).

  As shown in FIG. 5, the spindle head 60 is configured so that a cutting tool such as an end mill (not shown) can be attached and rotated, and a sintered layer obtained by sintering the material powder. Cutting can be performed on the surface and unnecessary portions. The cutting tools are preferably a plurality of types of cutting tools, and the cutting tools to be used can be replaced during modeling by an automatic tool changer (not shown).

  The light detection unit 41 is an image sensor such as a light receiving element or a CCD (Charge-Coupled Device), and is used for correcting the irradiation position of the laser light L. Details of the correction processing will be described later.

  Here, since both the spindle head 60 and the light detection unit 41 are provided in the same drive system (here, the machining head 57), a planar coordinate system (for controlling the position of the cutting tool mounted on the spindle head 60) ( In FIG. 5, the coordinates of the light detection unit 41 are known in the xy coordinates and the coordinates are represented as (x, y). The light detection unit 41 according to the first embodiment is preferably arranged on one axis in the plane coordinate system related to the position control of the cutting tool, that is, the x-axis or the y-axis. Here, the light detection unit 41 is disposed on the x-axis. In FIG. 5, the light detection unit 41 is arranged at (a, 0) with the cutting tool (main axis) as the origin (0, 0). With this configuration, it is possible to associate the planar coordinate system related to the position control of the cutting tool by the correction described later with the planar coordinate system related to the position control of the laser beam L with higher accuracy. In the following, the plane coordinate system related to the position control of the cutting tool parallel to the modeling area R is simply referred to as a main axis coordinate system, and the plane coordinate system related to the position control of the laser beam L parallel to the modeling area R is simply referred to as the laser beam coordinate. It is called a system.

  A fume diffusing device 17 is provided on the upper surface of the chamber 1 so as to cover the window 1a. The fume diffusing device 17 includes a cylindrical casing 17a and a cylindrical diffusing member 17c disposed in the casing 17a. An inert gas supply space 17d is provided between the housing 17a and the diffusion member 17c. An opening 17b is provided on the bottom surface of the housing 17a inside the diffusion member 17c. 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 17f is ejected downward of the fume diffusing device 17 through the opening 17b.

  The laser beam irradiation unit 13 is provided above the chamber 1. The laser beam irradiation unit 13 irradiates a predetermined portion of the material powder layer 8 formed on the modeling region R with the laser beam L to sinter the material powder at the irradiation position. Specifically, the laser light irradiation unit 13 includes a laser light source 42, biaxial galvanometer mirrors 43 a and 43 b, and a focus control unit 44. Each galvanometer mirror 43a, 43b includes an actuator for rotating the galvanometer mirror 43a, 43b, respectively.

The laser light source 42 emits laser light L. Here, the laser beam L is a laser capable of sintering 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 galvanometer mirrors 43a and 43b scan the laser light L output from the laser light source 42 two-dimensionally so as to be controllable. In particular, the galvanometer mirror 43a scans the laser beam L in the arrow B direction (X-axis direction), and the galvanometer mirror 43b scans the laser beam L in the arrow C direction (Y-axis direction). The rotation angles of the galvanometer mirrors 43a and 43b are controlled according to the magnitude of a rotation angle control signal input from a control device (not shown). With this feature, the laser beam L can be irradiated to a desired position by changing the magnitude of the rotation angle control signal input to each actuator of the galvanometer mirrors 43a and 43b.

  The laser light L that has passed through the galvanometer mirrors 43 a and 43 b is transmitted through the window 1 a provided in the chamber 1 and is applied to the material powder layer 8 formed in the modeling region R. The window 1a 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 window 1a can be made of quartz glass.

  Next, the inert gas supply / discharge system will be described. The inert gas supply / discharge system includes a plurality of inert gas supply ports and discharge ports provided in the chamber 1, and pipes that connect the supply ports and the discharge ports to the inert gas supply device 15 and the fume collector 19. Including. In the present embodiment, a supply port including a recoater head supply port 11fs, a chamber supply port 1b, a sub supply port 1e, and a fume diffusing device supply port 17g, a chamber discharge port 1c, a recoater head discharge port 11rs, and a sub discharge port And a discharge port including 1f.

  The recoater head supply port 11fs is provided so as to face the chamber discharge port 1c corresponding to the installation position of the chamber discharge port 1c. Preferably, the recoater head supply port 11fs faces the chamber discharge port 1c when the recoater head 11 is located on the opposite side of a predetermined irradiation region with respect to the installation position of the material supply device (not shown). As shown, the recoater head 11 is provided on one surface along the arrow C direction.

  The chamber discharge port 1c is provided on the side plate of the chamber 1 at a predetermined distance from a predetermined irradiation region so as to face the recoater head supply port 11fs. A suction device (not shown) may be provided so as to be connected to the chamber outlet 1c. The suction device helps to efficiently remove fumes from the irradiation path of the laser light L. Further, a larger amount of fumes can be discharged from the chamber discharge port 1c by the suction device, and the fumes are less likely to diffuse into the modeling space 1d.

  The chamber supply port 1b is provided on the end of the base table 4 so as to face the chamber discharge port 1c with a predetermined irradiation region in between. When the recoater head 11 passes through a predetermined irradiation region and the recoater head supply port 11fs faces the chamber discharge port 1c without interposing the predetermined irradiation region, the chamber supply port 1b is The head supply port 11fs is selectively switched to the chamber supply port 1b to be opened. For this reason, the chamber supply port 1b supplies the inert gas having the same predetermined pressure and flow rate as the inert gas supplied from the recoater head supply port 11fs toward the chamber discharge port 1c, so that it is always inert in the same direction. It is advantageous in that a gas flow can be created and stable sintering can be performed.

  The recoater head discharge port 11rs is provided along the arrow C direction on the side surface opposite to the one surface of the recoater head 11 where the recoater head supply port 11fs is provided. When the inert gas cannot be supplied from the recoater head supply port 11fs, in other words, when the inert gas is supplied from the chamber supply port 1b, some flow of the inert gas is created near the predetermined irradiation region. Therefore, the fumes can be more efficiently excluded from the irradiation path of the laser light L.

  In addition, the inert gas supply / discharge system of the present embodiment forms a clean inert gas that is provided on the side plate of the chamber 1 so as to face the chamber discharge port 1c and from which the fumes fed from the fume collector 19 are removed. A sub supply port 1e that supplies the space 1d, a fume diffusion device supply port 17g that is provided on the upper surface of the chamber 1 and supplies an inert gas to the fume diffusion device 17, and an upper side of the chamber 1 that is provided above the chamber discharge port 1c. And a sub-discharge port 1f for discharging an inert gas containing a large amount of fumes remaining in the gas.

  An inert gas supply device 15 and a fume collector 19 are connected to the inert gas supply system to the chamber 1. The inert gas supply device 15 has a function of supplying an inert gas, and includes, for example, a membrane nitrogen separator that extracts nitrogen gas from ambient air. In the present embodiment, as shown in FIG. 1, the recoater head supply port 11fs, the chamber supply port 1b, and the fume diffusion device supply port 17g are connected.

  The fume collector 19 has duct boxes 21 and 23 on the upstream side and the downstream side, respectively. The inert gas containing the fumes discharged from the chamber 1 through the chamber outlet 1c and the auxiliary outlet 1f is sent to the fume collector 19 through the duct box 21, and the clean inert gas from which the fumes have been removed in the fume collector 19 is supplied. It is sent to the sub supply port 1 e of the chamber 1 through the duct box 23. With such a configuration, the inert gas can be reused.

  As a fume discharge system, as shown in FIG. 1, a chamber discharge port 1 c, a recoater head discharge port 11 rs, a sub discharge port 1 f and a fume collector 19 are connected through a duct box 21. The clean inert gas after the fume is removed in the fume collector 19 is returned to the chamber 1 and reused.

(Layered modeling method and correction method according to the first embodiment)
Next, the layered manufacturing method and the correction method according to the first embodiment will be described with reference to FIGS. As will be described later, the correction method according to the first embodiment is preferably executed during additive manufacturing. 6 to 9, some of the components shown in FIG. 1 are omitted in consideration of visibility.

  First, the height of the modeling table 5 is adjusted to an appropriate position while the modeling plate 7 is placed on the modeling table 5 (FIG. 6). In this state, the recoater head 11 in which the material powder is filled in the material container 11a is moved from the left side to the right side of the modeling region R in the direction of arrow B in FIG. The material powder layer 8 is formed. During the movement of the recoater head 11, the cutting device 50 is retracted to the right side (retracted position) in FIG. 6 in order to prevent physical interference between the recoater head 11 and the cutting device 50. Further, since the cutting device 50 is configured to be movable in the vertical and horizontal directions, the cutting device 50 is not limited to being retracted to the right side in the figure, and may be further retracted in the vertically upward direction or in the depth direction of the paper surface.

  Next, the recoater head 11 is retracted out of the modeling region R, and the laser light irradiation portion of the material powder layer 8 is sintered by irradiating a predetermined portion in the material powder layer 8 with the laser light L. Thus, as shown in FIG. 7, a first sintered layer 81f which is a divided layer having a predetermined thickness with respect to the entire layered object is obtained.

  Next, the height of the modeling 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 modeling region R, whereby 2 on the sintered layer 81 f. The material powder layer 8 of the first layer is formed. The formation of the material powder layer 8 is called recoating.

  Here, the “correction method” described in detail below is executed. Hereinafter, the terms “target irradiation position” and “actual irradiation position” are used as positions in the detectable region in the light detection unit 41, respectively. In the present embodiment, the laser beam L used for forming the sintered layer is used as correction light for irradiating the target irradiation position of the light detection unit 41 and specifying an error from the actual irradiation position. In order to prevent the light detection unit 41 from being damaged by the laser light L, the output of the laser light L at the time of correction may be weakened within a range that can be detected by the light detection unit 41, or a translucent plate may be used. It may be configured to be incident on the light detection unit 41 after being attenuated through.

  As shown in FIG. 8, the cutting device 50 is moved to a predetermined measurement position so that the center of the detectable region in the light detection unit 41 is positioned at a first target irradiation position (details will be described later). A rotation control signal corresponding to the first target irradiation position is input to the galvanometer mirrors 43a and 43b, respectively. The galvanometer mirrors 43a and 43b are each directed at a predetermined angle. The laser light L is output from the laser light source 42 and is passed through the galvanometer mirrors 43a and 43b to a predetermined position (first actual irradiation position) on the detectable region in the light detection unit 41 and corresponding to the first target irradiation position. Irradiated. Here, the first actual irradiation position may be slightly deviated from the first target irradiation position due to the influence of thermal displacement. However, the displacement amount is relatively small with respect to the detectable region in the light detection unit 41, and the first actual irradiation position is included in the detectable region. That is, the first actual irradiation position is detected by the light detection unit 41.

  Next, the cutting device 50 is moved so that the center of the detectable region in the light detection unit 41 is positioned at the second target irradiation position. A rotation control signal corresponding to the second target irradiation position is input to the galvanometer mirrors 43a and 43b, respectively. The galvanometer mirrors 43a and 43b are each directed at a predetermined angle. Laser light L is output from the laser light source 42 and irradiated to a predetermined position (second actual irradiation position) corresponding to the second target irradiation position via the galvanometer mirrors 43a and 43b. Here, the second actual irradiation position may be slightly deviated from the second target irradiation position due to the influence of thermal displacement. However, the amount of displacement is relatively small with respect to the detectable region in the light detection unit 41, and the second actual irradiation position is included in the detectable region. That is, the second actual irradiation position is detected by the light detection unit 41.

  It is desirable that the first target irradiation position and the second target irradiation position are configured such that one of the x coordinate and the y coordinate shown in FIG. 5 is the same and the other is different. In this example, since the x coordinate is the same and the y coordinate is set to a different value, the cutting device 50 is moved in the depth direction in FIG. FIG. 10 shows the state before and after the movement. At this time, the first and second target irradiation positions are determined so as to be located at an equal distance from the origin of the laser beam coordinate system (the XY coordinates shown in FIG. 10 and the coordinates are indicated as [X, Y]). It is preferable to do. As a result, the measurement errors at the two points are substantially the same, and more accurate correction can be realized as a whole. In FIG. 10, the first target irradiation position is located at [0, B], and the second target irradiation position is located at [0, −B].

  Note that the irradiation position control of the laser beam L using the galvanometer mirrors 43a and 43b is to control the angle of the biaxial galvanometer mirrors 43a and 43b as described above. That is, even if the same angle is changed, the distance displacement on the irradiation position varies depending on the height of the irradiation position (light lever principle). Therefore, it is desirable that the photodetecting unit 41 be set at a predetermined height. In this correction method, since the light is irradiated onto the light detection unit 41 at a predetermined height different from the modeling table 5, it is necessary to associate an angle with an irradiation position at the predetermined height in advance.

  Furthermore, if there is no particular problem with physical interference with the recoater head 11, it is understood that it is preferable that the height difference between the light detection unit 41 and the galvanometer mirrors 43a and 43b is large from the viewpoint of correction accuracy. In other words, it is preferable to move the height of the cutting device 50 to a position as low as possible. This is because, based on the principle of the optical lever, even if the distance is the same, even if the error is the same, it can be measured as a large displacement.

Next, a correction unit (not shown) (for example, a control device (not shown) that controls the galvano mirrors 43a and 43b, a control circuit, etc.) causes an error Δ1 between the first target irradiation position and the first actual irradiation position and the second target An error Δ2 between the irradiation position and the second actual irradiation position is calculated. The correcting unit corrects the irradiation position of the laser beam L so that each target irradiation position and the actual irradiation position substantially coincide with each other. In other words, the correction unit corrects the irradiation position of the laser light L so that the errors Δ1 and Δ2 are substantially zero. Specifically, both translational deviation and rotational deviation components can be corrected. For reference, FIG. 11 shows a pattern of translational deviation and rotational deviation. The upper part of FIG. 11 shows the first target irradiation position and the first actual irradiation position, and the lower part shows the second target irradiation position and the second actual irradiation position. The outer circle is a detectable region in the light detection unit 41, and the inner circle indicates a target irradiation position (without hatching) and an actual irradiation position (with hatching). Δ1 and Δ2 are a combination of the X-direction translational deviation Δx, the Y-direction translational deviation Δy, and the rotational deviation Δθ. If a column vector of an arbitrary target irradiation position is p = ^T (x _p , y _p ), and a column vector of an actual irradiation position corresponding to the target irradiation position is q = ^T (x _q , y _q ), these are p = A _R q + d (1)

It can be expressed. However A _R is 2-dimensional rotation matrix to rotate angle -Δθ, d is a column vector of the translational displacement and the component ^{(d = T (Δx, Δy} )). That is, to calculate the A _R and d from Δ1 and Delta] 2, by applying the correction equation (1), and the actual irradiation position and the target irradiation position can be substantially matched ( "correcting method" is far. ).

  Next, by irradiating a predetermined portion in the material powder layer 8 with the laser beam L and sintering the laser beam irradiated portion of the material powder layer 8, as shown in FIG. 82f is obtained.

  By repeating the above steps, the third and subsequent sintered layers are formed. Adjacent sintered layers are firmly fixed to each other. After forming the required number of sintered layers, the shaped sintered body can be obtained by removing the unsintered material powder. This sintered body can be used, for example, as a mold for resin molding.

Note that a threshold for error may be provided in the above correction method. For example, the absolute value | Δ1 | of the error is compared with the threshold T1, the absolute value | Δ2 | of the error is compared with the threshold T2, and
| Δ1 |> T1 and | Δ2 |> T2
When satisfying at least one of
| Δ1 | ≧ T1 and | Δ2 | ≧ T2
When at least one of them is satisfied, the correcting means corrects the irradiation position of the laser light L.

  Further, when moving from the first target irradiation position to the second target irradiation position, the laser beam L may continue to be moved while moving in accordance with the movement, and the movement trajectory may be considered. It is understood that the measurement error can be reduced by taking the locus into consideration, and correction with higher reliability can be performed.

  Preferably, in order to avoid physical interference between the recoat operation by the recoater head 11 and the movement of the cutting device 50, the recoater head 11 is moved after the recoat operation (movement in a predetermined direction) is completed. When the movement is performed, the layered modeling can be performed in a shorter time as compared with the conventional technique. More preferably, by performing these substantially simultaneously while avoiding physical interference between the recoating operation by the recoater head 11 and the movement of the cutting device 50, the additive manufacturing can be performed in a shorter time. Further, in the correction method according to the first embodiment, since the light detection unit 41 is arranged on any one coordinate axis of the main axis coordinate system, highly accurate correction can be realized.

2. Second Embodiment Subsequently, an additive manufacturing apparatus according to a second embodiment will be described. In 2nd Embodiment, it has the some light detection part 41 which is the same number as the some target irradiation position at the time of correction | amendment. As shown in FIG. 12, here, two light detection units 41 (a first light detection unit 41 a and a second light detection unit 41 b) are provided in the cutting device 50. Here, since the spindle head 60, the first light detection unit 41a, and the second light detection unit 41b are all provided in the same drive system (here, the machining head 57), the spindle coordinate system (x shown in FIG. 12). -Y coordinate), the coordinates of the first light detection unit 41a and the second light detection unit 41b are known. Here, it is preferable that they are arranged equidistant from one axis (here, x-axis) in the plane coordinate system related to the position control of the cutting tool. In FIG. 12, the first light detector 41a is disposed at (a, b) and the second light detector 41b is disposed at (a, -b) with the cutting tool (main axis) as the origin. According to such a configuration, it is possible to associate the laser beam coordinate system and the principal axis coordinate system with higher accuracy.

(Correction method according to the second embodiment)
The layered manufacturing method and the correction method according to the second embodiment will be described with reference to FIGS. 6 to 9 and FIGS. 11 to 13. As will be described later, like the correction method according to the first embodiment, the correction method according to the second embodiment is also preferably performed during additive manufacturing.

  First, the height of the modeling table 5 is adjusted to an appropriate position while the modeling plate 7 is placed on the modeling table 5 (FIG. 6). In this state, the recoater head 11 in which the material powder is filled in the material container 11a is moved from the left side to the right side of the modeling region R in the direction of arrow B in FIG. The material powder layer 8 is formed. During the movement of the recoater head 11, the cutting device 50 is retracted to the right side (retracted position) in FIG. 6 in order to prevent physical interference between the recoater head 11 and the cutting device 50. Further, since the cutting device 50 is configured to be movable in the vertical and horizontal directions, the cutting device 50 is not limited to being retracted to the right side in the figure, and may be further retracted in the vertically upward direction or in the depth direction of the paper surface.

  Next, the recoater head 11 is retracted out of the modeling region R, and the laser light irradiation portion of the material powder layer 8 is sintered by irradiating a predetermined portion in the material powder layer 8 with the laser light L. Thus, as shown in FIG. 7, a first sintered layer 81f which is a divided layer having a predetermined thickness with respect to the entire layered object is obtained.

  Next, the height of the modeling 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 modeling region R, whereby 2 on the sintered layer 81 f. The material powder layer 8 of the first layer is formed.

  Here, the “correction method” described in detail below is executed. As in the first embodiment, in the present embodiment, laser light used for forming a sintered layer is used as correction light for irradiating the target irradiation position of the light detection unit 41 and specifying an error from the actual irradiation position. L is used. In order to prevent the light detection unit 41 from being damaged by the laser light L, the output of the laser light L at the time of correction may be weakened within a range that can be detected by the light detection unit 41, or a translucent plate may be used. It may be configured to be incident on the light detection unit 41 after being attenuated through.

  As shown in FIG. 8, the cutting device 50 is moved to a predetermined measurement position so that the center of the detectable region in the first light detection unit 41a is located at the first target irradiation position. At this time, as shown in FIG. 12, the center of the detectable region in the second light detection unit 41b is located at the second target irradiation position. As in the first embodiment, the first and second are positioned equidistant from the origin of the laser beam coordinate system (the XY coordinates shown in FIG. 13 and the coordinates are indicated as [X, Y]). It is preferable to determine the target irradiation position. As a result, the measurement errors at the two points are substantially the same, and more accurate correction can be realized as a whole. In FIG. 13, the first target irradiation position is located at [0, B], and the second target irradiation position is located at [0, -B].

  A rotation control signal corresponding to the first target irradiation position is input to the galvanometer mirrors 43a and 43b, respectively. The galvanometer mirrors 43a and 43b are each directed at a predetermined angle. Laser light L is output from the laser light source 42 and irradiated to a predetermined position (first actual irradiation position) corresponding to the first target irradiation position via the galvanometer mirrors 43a and 43b. Here, the first actual irradiation position may be slightly deviated from the first target irradiation position due to the influence of thermal displacement. However, the amount of displacement is relatively small with respect to the detectable region in the first light detection unit 41a, and the first actual irradiation position is also included in the detectable region. That is, the first actual irradiation position is detected by the first light detection unit 41a.

  Subsequently, a rotation control signal corresponding to the second target irradiation position is input to the galvanometer mirrors 43a and 43b, respectively. The galvanometer mirrors 43a and 43b are each directed at a predetermined angle. Laser light L is output from the laser light source 42 and irradiated to a predetermined position (second actual irradiation position) corresponding to the second target irradiation position via the galvanometer mirrors 43a and 43b. Here, the second actual irradiation position may be slightly deviated from the second target irradiation position due to the influence of thermal displacement. However, the displacement amount is relatively small with respect to the detectable region in the second light detection unit 41b, and the second actual irradiation position is included in the detectable region. That is, the second actual irradiation position is detected by the second light detection unit 41b.

  Next, a correction unit (not shown) (for example, a control device (not shown) that controls the galvano mirrors 43a and 43b, a control circuit, or the like) causes an error Δ1 between the first target irradiation position and the first actual irradiation position and the second target. An error Δ2 between the irradiation position and the second actual irradiation position is calculated. The correcting unit corrects the irradiation position of the laser beam L so that each target irradiation position and the actual irradiation position substantially coincide with each other. In other words, the correction unit corrects the irradiation position of the laser light L so that the errors Δ1 and Δ2 are substantially zero. Specifically, as in the first embodiment, both translational deviation and rotational deviation components as shown in FIG. 11 can be corrected. That is, the actual irradiation position and the target irradiation position can be made substantially coincident (the “correction method” is up to here).

  Next, as shown in FIG. 9, the second layer of the material powder layer 8 is sintered by irradiating the laser beam L to a predetermined site in the material powder layer 8 to sinter the laser beam L irradiated site. A sintered layer 82f is obtained.

  By repeating the above steps, the third and subsequent sintered layers are formed. Adjacent sintered layers are firmly fixed to each other. After forming the required number of sintered layers, the shaped sintered body can be obtained by removing the unsintered material powder. This sintered body can be used, for example, as a mold for resin molding.

As in the first embodiment, a threshold for error may be provided in the correction method. For example, the absolute value | Δ1 | of the error is compared with the threshold T1, the absolute value | Δ2 | of the error is compared with the threshold T2, and
| Δ1 |> T1 and | Δ2 |> T2
When satisfying at least one of
| Δ1 | ≧ T1 and | Δ2 | ≧ T2
When at least one of them is satisfied, the correcting means corrects the irradiation position of the laser light L.

  Preferably, in order to avoid physical interference between the recoat operation by the recoater head 11 and the movement of the cutting device 50, the recoater head 11 is moved after the recoat operation (movement in a predetermined direction) is completed. When the movement is performed, the layered modeling can be performed in a shorter time as compared with the conventional technique. More preferably, by performing these substantially simultaneously while avoiding physical interference between the recoating operation by the recoater head 11 and the movement of the cutting device 50, the additive manufacturing can be performed in a shorter time. In particular, the correction method according to the second embodiment can irradiate the laser beam L toward the first target irradiation position and the second target irradiation position without the movement of the cutting device 50. Correction of the irradiation position of the light L can be realized.

  The correction according to the first embodiment and the second embodiment may be performed at an arbitrary timing, but it is desirable that the frequency of correction is high in order to realize modeling with higher accuracy. Further, such correction is preferably performed during recoating from the viewpoint of shortening the modeling time, particularly when the frequency is high. On the other hand, since it is desirable to reduce the size of the chamber 1 in order to increase the supply efficiency of inert gas and the removal of fumes, when correction is performed during recoating, the cutting device 50 or the cutting tool and the recoater head 11 are corrected. May physically interfere with each other.

  Therefore, when the recoater head 11 is provided with the blades 11fb and 11rb on both side surfaces as in this embodiment and the moving direction of the recoater head 11 is switched every time recoating, the moving direction of the recoater head 11 and the correction are corrected. It is desirable that the correction is executed when the moving direction of the cutting device 50 at the start (that is, the direction when moving from the retracted position to the measuring position) matches. Further, a blade may be provided only on one side of the recoater head 11 so that the moving direction of the recoater head 11 during recoating is always constant. In this case, the moving direction of the recoater head 11 may be configured so that the moving direction of the cutting device 50 at the start of correction coincides. According to the above configuration, the above-described physical interference can be prevented even when correction is performed during recoating.

  The present invention can also be implemented in the following modes.

  First, in the above embodiment, the pair of galvanometer mirrors 43a and 43b is used as the scanning means for the laser light L, but the laser light L may be scanned by another means.

  Secondly, coaxial light having a different optical axis from the laser light L used for sintering the material powder and having the same optical axis as the laser light L may be used as the correction light. The correction light is, for example, guide light for displaying the irradiation position of the invisible laser light L. The above correction can be performed based on the irradiation position of the coaxial light.

  Third, the target irradiation position may be one or three or more. In the case of one, correction with higher accuracy can be realized by setting the target irradiation position as the origin of the laser beam coordinate system. However, it should be noted that when there is one, the shift of the rotational component cannot be corrected.

1: chamber, 1a: window, 1b: chamber supply port, 1c: chamber discharge port, 1d: modeling space, 1e: sub-supply port, 1f: sub-discharge port, 3: powder layer forming device, 4: base stand, 5: modeling table, 7: modeling plate, 8: material powder layer, 11: recoater head, 11a: material storage unit, 11b: material supply unit, 11c: material discharge unit, 11fb, 11rb: blade, 11fs: Ricoh 11 head: discharge port, 11 rs: recoater head discharge port, 13: laser beam irradiation unit, 15: inert gas supply device, 17: fume diffusion device, 17a: housing, 17b: opening, 17c: diffusion member, 17d : Inert gas supply space, 17e: pores, 17f: clean room, 17g: fume diffusion device supply port, 19: fume collector, 21, 23: duct box, 26: powder holding wall, 1: modeling table drive mechanism, 41: light detection unit, 41a: first light detection unit, 41b: second light detection unit, 42: laser light source, 43a, 43b: galvanometer mirror, 44: focus control unit, 50: cutting Apparatus, 57: Processing head, 60: Spindle head, 81f, 82f: Sintered layer, L: Laser light, R: Modeling area.

Claims (6)

A chamber covering the modeling area and filled with an inert gas;
A laser beam irradiation unit for irradiating a laser beam for sintering the material powder in the irradiation region on the material powder layer formed on the modeling region;
A cutting device for moving a cutting tool for cutting a sintered layer obtained by sintering the material powder in a vertical and horizontal direction in the chamber;
A light detection unit that detects an irradiation position of correction light composed of coaxial light having the same optical axis as the laser light or the laser light;
Correction means for correcting the irradiation position of the laser beam based on the irradiation position of the correction light detected by the light detection unit;
With
The light detection unit is provided in the cutting device ,
The laser light irradiation unit irradiates the correction light on a predetermined position corresponding to a target irradiation position on the detectable region in the light detection unit,
The correction unit calculates an error between the target irradiation position and the correction light irradiation position, and corrects the laser light irradiation position so that the target irradiation position and the correction light irradiation position coincide with each other. you said,
Additive manufacturing equipment. A recoater head that forms the material powder layer by spreading the material powder on the modeling region while moving in the chamber;
The cutting device moves the photodetecting unit from the retracted position to the measuring position with or after the movement of the recoater head in a predetermined direction,
The correction unit is configured to correct the irradiation position of the laser beam based on the irradiation position of the correction light detected by the light detection unit in a state where the light detection unit is at the measurement position.
The additive manufacturing apparatus according to claim 1. The light detection unit is disposed on any one coordinate axis of a planar coordinate system related to position control of the cutting tool.
The additive manufacturing apparatus according to claim 1 or 2. The cutting apparatus moves the light detection unit so as to detect laser light irradiated to two points that are equidistant from the origin of a planar coordinate system related to position control of the laser light.
The additive manufacturing apparatus according to claim 3. The light detection unit includes a plurality of light detection units including first and second light detection units,
The correction means is configured to correct the irradiation position of the laser beam based on the irradiation position of the correction light detected by the first and second light detection units,
The first and second light detection units are arranged equidistant from any one coordinate axis of the planar coordinate system related to the position control of the cutting tool.
The additive manufacturing apparatus according to claim 1 or 2. In the cutting apparatus, the first and second light detection units respectively detect the laser light irradiated to two points that are equidistant from the origin of the planar coordinate system related to the position control of the laser light. Move the
The additive manufacturing apparatus according to claim 5.