JP3599059B2 - Method and apparatus for manufacturing three-dimensional shaped object - Google Patents

Description

  The present invention relates to a method and an apparatus for manufacturing a three-dimensionally shaped object by irradiating a light beam to a powder layer to form a sintered layer and stacking the sintered layers to manufacture a desired three-dimensionally shaped object. Things.

  The powder layer formed on the stage is irradiated with a light beam (directional energy beam, for example, a laser) to form a sintered layer, and a new powder layer is formed on the sintered layer and irradiated with a light beam. It is known in Japanese Patent Application Laid-Open No. 1-502890 (Patent Document 1) and the like that manufacturing a three-dimensional shaped object by repeatedly stacking sintered layers by forming a sintered layer by repeating the above. I have.

  Japanese Patent Application Laid-Open No. 2002-115004 (Patent Literature 2) discloses that, while a three-dimensional shaped object is manufactured by stacking sintered layers, the surface of the shaped object as a stacked layer of the sintered layers is gradually finished. Is shown in

  When a desired portion of the powder layer 10 is irradiated with a light beam for selective sintering, sparks scatter as shown in FIG. 18 and powder melting residues contained in the spark adhere to the surface of the sintered layer 11. However, a protruding abnormal sintered portion 19 may be formed.

  In the case where the finishing process is performed gradually in the process of laminating the sintered layers 11, processing chips (cutting chips) are scattered, and the processing chips cause projections on the surface of the next powder layer 10. Then, at the time of the next sintering, a protruding abnormal sintered portion 19 may be generated.

When the thickness of each powder layer 10 is set to 50 μm in order to obtain a three-dimensional shaped object having high density and high shape accuracy, since the particle diameter of the powder particles is about 10 to 50 μm, as described above, When the abnormal sintering portion 19 occurs, the abnormal sintering portion 19 often jumps out of the next powder layer 10. In this case, a blade for leveling the surface of the powder layer 10 is used. Will be caught on the abnormally sintered portion 19 and the molding process will be stopped.
Japanese Patent Publication No. 1-502890 JP 2002-115004 A

    The present invention has been made in view of the above-described conventional problems, and provides a method and apparatus for manufacturing a three-dimensionally shaped object that does not cause the stop of modeling due to the occurrence of an abnormally sintered portion. It is an issue.

Thus, the method for manufacturing a three-dimensionally shaped object according to the present invention, a new powder layer is laminated on the surface of a sintered layer formed by irradiating a predetermined portion of the powder layer with a light beam and sintering. In producing a three-dimensionally shaped object by repeatedly forming a new sintered layer integrated with the lower sintered layer by irradiating a predetermined location of the new powder layer with a light beam and sintering it It is characterized in that the presence or absence of a protruding abnormal sintered portion generated on the surface of the sintered layer is detected each time each sintered layer is formed, and the abnormal sintered portion is removed when the abnormal sintered portion is detected. are doing. The abnormally sintered part is removed, so that the molding does not stop due to the occurrence of the abnormally sintered part.

Moreover, to detect the presence or absence of abnormal sintering of the sintered layer surface per formation of the sintered layer, since the removal of the abnormal sintering section upon detection of the abnormal sintering portion, removal of the abnormal sintering unit The process can be minimized.

  In addition, when the presence or absence of an abnormally sintered part is detected by the driving load applied to the blade for leveling the surface of the powder layer, there is no need to prepare a separate device for detecting the abnormally sintered part. Detection can be performed at low cost, and the abnormality detection unit can be reliably detected.

  The presence or absence of the abnormally sintered portion may be optically detected. In this case, the position where the abnormally sintered part is generated can be grasped two-dimensionally to easily reduce the processing range for removing the abnormally sintered part.

  Further, if the processing for removing the abnormally sintered portion is performed only on the position near the detected abnormally sintered portion, the time required for the removing process can be reduced.

  In addition, when the removal process is performed on the entire surface of the sintered layer or the entire surface including the powder layer, even if there is an abnormal sintered portion that was missed at the time of detection, it can be surely removed.

  Further, if the removal processing is performed only on the portion located in the passage area of the blade for leveling the surface of the powder layer, the time required for the removal processing can be reduced.

  Further, the apparatus for manufacturing a three-dimensionally shaped object according to the present invention is a light beam irradiation means for irradiating a predetermined position of the powder layer formed on the stage with a light beam and sintering the powder at the irradiation position, and on the stage and Powder layer forming means for supplying a powder layer on a sintered layer already sintered, and processing means for finishing the surface of a modeled object as a laminate of sintered layers during repeated formation of the sintered layer And detecting means for detecting whether an abnormally sintered part is present on the surface of the formed sintered layer, and removing means for removing the abnormally sintered part by detecting the abnormally sintered part by the detecting means. It has special features.

  By using the processing means driven along the removal path calculated according to the position of the abnormally sintered part detected by the detecting means as the removing means, prevention of molding stop due to the abnormally sintered part is achieved at low cost. can do.

In the method of manufacturing a three-dimensionally shaped object according to the present invention, the abnormally sintered part is removed, and the molding is stopped due to the occurrence of the abnormally sintered part. Since the abnormally sintered portion is removed when the abnormally sintered portion is detected, the process of removing the abnormally sintered portion can be minimized.

  Further, the apparatus for manufacturing a three-dimensionally shaped object according to the present invention is capable of detecting and removing an abnormally sintered portion even if an abnormally sintered portion is generated. Can be prevented from falling into a state of modeling stop due to the above.

  Hereinafter, the present invention will be described in detail based on an example of an embodiment. The apparatus for manufacturing a three-dimensionally shaped object shown in FIGS. 2 and 3 includes a powder layer forming unit 2, a light beam irradiation unit 3, a processing unit 4, Detecting means for detecting whether or not the abnormally sintered portion 19 is present on the surface of the sintered layer, removing means for removing the abnormally sintered portion 19 by detecting the abnormally sintered portion 19, and a powder layer. The powder layer forming means 2 is composed of a chamber 20 in which a forming means 2 and a processing means 4 are housed. The powder layer 10 having a predetermined thickness Δt1 is formed on the stage 20 by supplying the metal powder in the powder tank 23 with the squeezing blade 21 and leveling it.

  The light beam irradiating means 3 irradiates the laser beam output from the laser oscillator 30 to the powder layer 10 via the beam shape correcting means 35 and the scanning optical system such as the galvanomirror 31 and is disposed outside the chamber 5. The light beam emitted from the light beam irradiation means 3 is applied to the powder layer 10 through a light transmitting window 50 provided in the chamber 5. The window 50 is made of a material that allows laser light to pass therethrough. When the laser oscillator 30 is a carbon dioxide laser, a ZnSe flat plate or the like can be used.

  The processing means 4 is configured such that a milling head 41 is provided on the base of the powder layer forming means 2 via an XY drive mechanism 40.

  Here, as the detection means, a means for detecting the motor torque for driving the blade 21 is used, and the removal means also serves as the processing means 4.

  As shown in FIG. 3, the three-dimensionally shaped object is supplied with the metal powder overflowing from the powder tank 23 onto the surface of the molding base 22 on the upper surface of the stage 20 by the blade 21 and is leveled by the blade 21 at the same time. As a result, the first powder layer 10 is formed, and a portion of the powder layer 10 to be cured is irradiated with a light beam (laser) L to sinter the metal powder and to form a sintered layer integrated with the base 22. 11 is formed.

  Thereafter, the stage 20 is slightly lowered, metal powder is supplied again, and the powder is leveled by the blade 21 so that the second powder layer 10 is placed on the first powder layer 10 (and the sintered layer 11). A light beam (laser) L is applied to a portion of the second powder layer 10 to be hardened to sinter the powder to form a sintered layer 11 integrated with the lower sintered layer 11. I do.

  The process of lowering the stage 20 to form a new powder layer 10 and irradiating a light beam to make the required portion a sintered layer 11 is repeated, thereby forming a desired three-dimensional shape as a laminate of sintered layers. A carbon dioxide laser can be suitably used as the light beam, and the thickness Δt1 of the powder layer 10 is determined when the obtained three-dimensionally shaped object is used for a molding die or the like. , And about 0.05 mm.

  The irradiation path (hatching path) of the light beam is created in advance from the three-dimensional CAD data as shown in FIG. That is, the contour shape data of each section obtained by slicing the STL data generated from the three-dimensional CAD model at a constant pitch (0.05 mm pitch when Δt1 is 0.05 mm) is used. At this time, a light beam is irradiated so that at least the outermost surface of the three-dimensionally shaped object can be sintered so as to have a high density (porosity of 5% or less), and the inside is sintered so as to have a low density. In other words, the shape model data is divided into the surface layer and the interior in advance, and the sintering conditions are such that the inside is porous, and the surface layer is the condition where the powder is almost melted and the density is high. By irradiating with a light beam, a model having a dense surface can be obtained at high speed.

  After the powder layer 10 is formed, the process of irradiating a light beam to form the sintered layer 11 is repeated, and the total thickness of the sintered layer 11 is, for example, the thickness of the milling head 41 in the processing means 4. When the required value obtained from the tool length or the like is reached, the processing means 4 is once operated to cut the surface (mainly the upper side surface) of the modeled object. For example, if the tool (ball end mill) of the milling head 41 can perform cutting with a diameter of 1 mm, an effective blade length of 3 mm, and a depth of 3 mm, and the thickness Δt1 of the powder layer 10 is 0.05 mm, the baking of 60 layers is performed. When the tie layer 11 is formed, the processing means 4 is operated.

  The cutting and finishing processing by the processing means 4 removes the low-density surface layer due to the powder adhering to the surface of the modeled object and, at the same time, sharpens the high-density portion to completely expose the high-density portion on the surface of the modeled object. Can be.

  The cutting path by the processing means 4 is created in advance from the three-dimensional CAD data, similarly to the irradiation path of the light beam. At this time, the processing path is determined by applying the contour processing, but the Z-direction pitch does not need to stick to the lamination pitch at the time of sintering, and in the case of a gentle inclination, the Z-direction pitch is made finer and interpolated. Be prepared to obtain a smooth surface.

  Here, the above-described detection means and removal means are provided in order to eliminate a situation in which molding is stopped due to the occurrence of the abnormal sintering portion 19 in the form of a protrusion on the upper surface of the uppermost sintered layer 11. However, as described above, the detecting means is constituted by detecting the driving motor torque of the blade 21, and the processing means 4 also serves as the removing means.

  For this reason, when the powder is supplied to the upper surface by moving the blade 21 by driving the motor after the formation of the sintered layer 11, as shown in FIG. 1, the powder is formed on the surface of the uppermost sintered layer 11. When the height of the protruding abnormal sintered portion 19 is higher than the thickness of the powder layer 10 to be formed next, the motor torque for driving the blade 21 increases because the blade 21 hits the tip of the abnormal sintered portion 19. If this torque value exceeds a predetermined threshold value as shown in FIG. 6, the control circuit controlling the manufacturing apparatus stops the driving of the blade 21 and temporarily retreats, and the abnormal sintering by the processing means 4 is performed. The portion of the portion 19 located in the region where the blade 21 passes is cut and removed, and thereafter, the powder layer 10 is formed by the blade 21 again. FIG. 5 is a flowchart of the operation in this case, that is, the case where the abnormal sintering portion 19 is removed by configuring the detecting means by detecting the motor torque for driving the blade 21.

  As shown in FIG. 7, the tip of the protruding abnormal sintered portion 19 is removed by making the lower end of the cutting tool in the processing means 4 coincide with the movement locus Mv of the lower end of the blade 21. It is possible to reliably prevent the blade 21 from hitting the abnormally sintered portion 19 when the powder layer 10 is formed by using the powder layer 21 and to minimize the amount of cutting.

  If an encoder is attached to the motor for driving the blade 21, the location of the abnormally sintered portion 19 in the driving direction of the blade 21 can be detected. As shown in FIG. 8, the range in which the processing means 4 is moved can be kept within the band-shaped range A1 including the abnormally sintered portion 19 and having a predetermined width in the operation direction of the blade 21. However, since there is a possibility that the protruding abnormal sintered portion 19 may exist outside the band-shaped range A1, the blade 21 moving area (from where the existence of the abnormal sintered portion 19 is confirmed) (A5 in FIG. 9A) may be used as a removal target region of the abnormally sintered portion 19. Also, by referring to the information of the sintered area, as shown in FIG. 9 (b) or 9 (c), it is possible to limit the removal processing target area within a range in which a required margin width ww is added. It may be.

  As the detection means, as shown in FIG. 10, a pair of a detection laser irradiation unit 80 and a light receiving unit 81 may be used. As shown in FIG. The sintering surface may be imaged by the imaging means 82 and the laser cutting method may be used to detect the presence or absence of the abnormal sintering portion 19 from the photographed image (see FIG. 11B).

  With the latter detection means, the position at which the abnormally sintered portion 19 has occurred can be specified in two axial directions. As shown in (5), it can be kept within a predetermined minute range A2 centering on the abnormally sintered portion 19. FIG. 13 is a flowchart in the case where the abnormal sintering portion 19 is removed based on such optical detection.

  When the presence of the abnormally sintered portion 19 is detected by using the blade 21, the above-described removal is performed with the sintered layer 11 formed and the stage 20 lowered by one step. In the case of detecting the presence of the joint 19, the removal processing may be performed after the formation of the sintered layer 11 and before lowering the stage 20 by one step. By shifting the lower end position upward, it corresponds to the passage area of the blade 21 at the time of the next powder supply.

  The detecting means may be capable of detecting only the presence or absence of the abnormally sintered portion 19 and not detecting the position. At this time, as shown in FIG. An area A5 set based on the maximum and minimum coordinate values of the area where the consolidation layer 11 is formed and the margin width ww, or an area A3 in which the area of the sintered layer 11 is expanded outward by a predetermined offset amount os is removed. Should be performed. Even when the entire surface A4 is used as the removal processing area, the portion outside the passage area of the blade 21 for leveling the surface of the powder layer 10 does not cause any trouble even if the abnormally sintered portion 19 exists. You may want to exclude it.

  The processing path for moving the processing means 4 is determined by calculation by the control circuit according to the removal processing ranges A1 to A5. If the removal processing range is A4, the removal processing path can be determined in advance.

  In each of the above examples, every time the sintered layer 11 is formed, the presence of the abnormal sintering portion 19 that is a problem is detected, and the removal processing is performed only when the abnormal sintering portion 19 exists, as shown in FIG. Regardless of whether or not the abnormally sintered portion 19 is present, removal processing for removing the abnormally sintered portion 19 may be performed each time the sintered layer 11 is formed. In this case as well, the processing means 4 can be used for the removal processing. However, the area to be removed is as wide as A4, A5, or A3. The abnormal sintering portion 19 may be removed by a removing means C used only for removing the portion 19, for example, a rotary cutter C as shown in FIG. Since the required width range can be cut at a time, the removal processing is performed every time the sintered layer 11 is formed. The time involved in the production of the product is almost unchanged.

  In addition, when the entire area where the sintered layer 11 exists is set as the removal target area as described above, the thickness of the powder layer 10 is made larger than the design value H (for example, 50 μm) of the thickness of the laminated sintered layer 11. At the same time, the thickness of the sintered layer 11 obtained by sintering is also set to a value larger than the design value H (for example, 80 μm), and the removal processing performed each time the sintered layer 11 is formed is shown in FIG. As described above, not only the abnormally sintered portion 19 but also the surface of the sintered layer 11 is ground by the difference between the above values (30 μm in the above example) so that the thickness of the sintered layer 11 matches the design value H. You may.

  Providing the removing means C separately from the processing means 4 is of course effective also in the case where the detecting means is provided to remove the abnormally sintered part 19 only when the presence of the abnormally sintered part 19 is detected. In addition, although the example in which the processing means 4 is provided to perform the finishing processing of the surface of the modeled product as the laminate of the sintered layer 11 during the repetition of the formation of the sintered layer 11, the processing means 4 is provided. The present invention can be applied to the case where no means is provided by providing a removing means or a removing means and a detecting means.

It is operation | movement explanatory drawing of an example of Embodiment of this invention. (a) is a cutaway perspective view of the same, and (b) is a partial perspective view of the same. It is operation | movement explanatory drawing regarding shaping same as the above. FIG. 3 is a data flow diagram relating to modeling. It is a flowchart regarding detection and removal of an abnormal sintered part same as the above. It is explanatory drawing about the abnormality detection part detection operation same as the above. It is explanatory drawing which shows the detail about removal processing same as the above. It is a top view which shows an example of the removal processing range same as the above. (a), (b), (c) is a plan view showing another example of the removal processing range of the above. It is explanatory drawing of another example of a detection means same as the above. (a) and (b) are explanatory diagrams of another example of the detection means of the above. It is a top view which shows the other example of the removal processing range same as the above. It is a flowchart regarding detection and removal of an abnormal sintered part same as the above. (a) (b) (c) is a top view which shows another example of the removal processing range same as the above. 13 is a flowchart of another example. (a) and (b) are a sectional view and a perspective view of an example provided with a removing means. It is an explanatory view showing details about other examples of removal processing. (a) (b) is an explanatory view showing a conventional problem.

Explanation of reference numerals

2 Powder layer forming means 3 Light beam irradiation means 4 Processing means 10 Powder layer 11 Sintered layer 19 Abnormal sintering part L Light beam

Claims (8)

A new powder layer is laminated on the surface of the sintered layer formed by irradiating a predetermined portion of the powder layer with a light beam and sintering, and sintering by irradiating a predetermined portion of the new powder layer with a light beam. By repeating the process of forming a new sintered layer integrated with the lower sintered layer to produce a three-dimensional shaped object, the surface of the sintered layer was generated each time each sintered layer was formed A method for manufacturing a three-dimensionally shaped object, comprising: detecting presence or absence of a protruding abnormal sintered part; and removing the abnormal sintered part when the abnormal sintered part is detected . The method for producing a three-dimensionally shaped object according to claim 1, wherein the presence or absence of the abnormally sintered portion is detected by a driving load applied to a blade for leveling the surface of the powder layer . The method for manufacturing a three-dimensionally shaped object according to claim 1, wherein the presence or absence of the abnormally sintered portion is optically detected . The method for producing a three-dimensionally shaped object according to claim 2, wherein the processing for removing the abnormally sintered portion is performed only on a position near the detected abnormally sintered portion . 5. The method for manufacturing a three-dimensionally shaped object according to any one of claims 1 to 3, wherein the removing process is performed on the entire surface of the sintered layer or the entire surface including the powder layer . The method for producing a three-dimensionally shaped object according to any one of claims 1 to 3, wherein the removal processing is performed only on a portion located in a passage area of a blade for leveling the surface of the powder layer. . Light beam irradiating means for irradiating a predetermined position of the powder layer formed on the stage with a light beam to sinter the powder at the irradiation position, and supplying the powder layer on the stage and on the sintered layer already sintered Powder layer forming means, processing means for finishing the surface of the modeled object as a laminate of the sintered layer during repetition of forming the sintered layer, and abnormal sintering on the surface of the formed sintered layer. An apparatus for producing a three-dimensionally shaped object, comprising: a detecting unit for detecting whether or not there is a defect, and a removing unit for removing the abnormally sintered portion by detecting the abnormally sintered portion by the detecting unit. 8. The three-dimensionally shaped object according to claim 7, wherein the removing means is the processing means driven along a removing path calculated in accordance with a position of the abnormally sintered portion detected by the detecting means. manufacturing device.

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