JP4655063B2 - Manufacturing method of three-dimensional shaped object - Google Patents

Description

  The present invention relates to a method of manufacturing a three-dimensional shaped object in which a plurality of sintered layers are laminated and integrated by repeating a step of forming a sintered layer by irradiating a layer of powder material with a light beam.

  There is a method for manufacturing a three-dimensional shaped object known as an optical modeling method. For example, the manufacturing method disclosed in Patent Document 1 forms a sintered layer by irradiating a predetermined portion of a powder material layer with a light beam to sinter the powder at the corresponding portion, and A new sintered layer that is integrated with a lower sintered layer by coating a new layer of powder material on the top and irradiating a predetermined portion of the powder layer with a light beam to sinter the powder at that location. By repeating the process of forming a powder sintered part (three-dimensional shaped article) in which a plurality of sintered layers are laminated and integrated, design data (CAD data) of the three-dimensional shaped article ) Is slicing the model to the desired layer thickness, and the light beam is irradiated based on the cross-sectional shape data of each layer. Compared with the manufacturing method by the Rukoto can.

By the way, unnecessary powder adheres to the periphery of the portion that is irradiated with the light beam and sintered and hardened, and the surface layer having a low density is formed on the molded article due to the transferred heat. . In order to remove the low-density surface layer and obtain a three-dimensional shaped article having a smooth surface, for example, Patent Document 2 discloses a surface portion or a part of a shaped article produced so far after formation of a sintered layer. A method is described in which a step of removing at least one of unnecessary portions is inserted into a plurality of times of manufacturing a sintered layer. By adopting this method, it is possible to repeat the production of the sintered layer and the removal of at least one of the surface part or the unnecessary part in the molded article produced so far, so that the surface can be obtained without any restrictions such as the drill length. Can be finished.
Japanese Patent No. 2620353 Japanese Patent No. 3446733

  When the method described in Patent Document 2 is adopted, each sintered layer has a size (horizontal cross-sectional area) larger than the original value, and the surface portion or unnecessary portion of the molded article manufactured so far. By making at least one of the original dimensions when removing at least one of them, a smooth and highly hard surface can be obtained with certainty, but the following new problems arise.

  In other words, if the amount of unnecessary powder adhering to the surface of the modeled object that has been manufactured so far is large or the size of the unnecessary powder is large, cutting and removing with a thin cutting tool will only remove little by little. It is very inefficient because it cannot be done. However, depending on the shape of the three-dimensional shaped object, there are thin groove shapes and complex shapes that can only be processed with a thin cutting tool.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a three-dimensional shaped object that can perform efficient cutting even if a thin cutting tool is used in the removal step. And

In order to solve the above-mentioned problem, the manufacturing method of the three-dimensional shaped object according to claim 1 sinters by irradiating a predetermined part of the layer of the powder material with a light beam and sintering the powder at the corresponding part. A layer is formed, and a new layer of powder material is coated on the sintered layer, and a predetermined portion is irradiated with a light beam to sinter the powder at the corresponding location, thereby integrating with the lower sintered layer. When forming a three-dimensional shaped object in which a plurality of sintered layers are laminated and integrated by repeating the formation of a new sintered layer, the surface of the shaped object manufactured so far after the formation of the sintered layer In the method for manufacturing a three-dimensional shaped article, in which the removal process is a cutting process, the smaller the tool diameter of the cutting tool used in the removal process, Coating thickness of powder material supplied to form a bond And wherein the setting a small amount of energy of the light beam to be irradiated.

According to a second aspect of the present invention, in the method for manufacturing a three-dimensionally shaped object according to the first aspect, in the removing step, the smaller the tool diameter of the cutting tool used, the smaller the condensing diameter of the light beam. It is characterized by setting.

The invention according to claim 3 is the method for producing a three-dimensional shaped article according to claim 1 or 2, wherein the particle diameter of the powder to be further coated is smaller as the tool diameter of the cutting tool used is smaller in the removing step. Is also set to be small .

Invention of Claim 4 is a manufacturing method of the three-dimensional shape molded article of any one of Claims 1-3 , The powder material contains metal powder, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, even if it uses a thin cutting tool, the manufacturing method of the three-dimensional shaped molded object which can perform efficient cutting can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the present invention may be described with specific examples, but the present invention is not limited to the following specific examples.

  FIG. 1 shows a three-dimensional shaped article manufacturing apparatus (hereinafter simply referred to as “manufacturing apparatus”) according to an embodiment.

  The manufacturing apparatus uses a squeezing blade 21 to smooth the powder material supplied onto a lifting table 20 that moves up and down in a space surrounded by a cylinder, so that the powder material layer has a predetermined thickness Δt1 (see FIG. 2). The powder layer forming means 2 for forming the (powder layer) 10 and the light beam (laser) L output from the laser oscillator 30 provided above the powder layer forming means 2 through a scanning optical system such as a galvanometer mirror 31 By irradiating a predetermined portion of the powder layer 10 to sinter the portion to form the sintered layer 11, a sintered layer forming means 3, and a ball end mill are provided to the base portion of the powder layer forming means 2 in an XY drive. A surface part or an unnecessary part of a shaped article manufactured so far by a cutting tool 41 provided through a mechanism (preferably one driven by a linear motion linear motor in terms of speeding up) And removal means 4 for removing one even without the the basic structure.

  As shown in FIG. 2, the manufacture of the three-dimensional shaped article in this product is for modeling the upper surface of the lifting table 20 which is an adjusting means for adjusting the relative distance between the sintered layer forming means 3 and the sintered layer 11. A powder material is supplied to the surface of the base 22 and is smoothed by the blade 21 to form the first powder layer 10, and a portion of the powder layer 10 to be cured is irradiated with the light beam L to sinter the powder. Thus, the sintered layer 11 integrated with the base 22 is formed.

  Thereafter, the lifting table 20 is slightly lowered, the powder material is supplied again, and the blade 21 is used to form the second powder layer 10, and the portion of the powder layer 10 to be cured is irradiated with the light beam L. Then, the powder is sintered to form the sintered layer 11 integrated with the lower sintered layer 11.

  By repeating the above steps, a target three-dimensional shaped object is manufactured.

  Here, the powder material includes a fine metal powder having a particle size of 1 to 100 μm. Specifically, the powder material is a mixed powder of chromium molybdenum steel (SCM440), nickel (Ni), copper manganese alloy (CuMnNi), and graphite (C), and the blending ratio is (70 wt% SCM440-20). Wt% Ni-9 wt% CuMnNi) +0.3 wt% C.

  As the light beam L, a carbon dioxide laser is used. The irradiation path of the light beam L is created in advance from three-dimensional CAD data. That is, contour shape data of each cross section obtained by slicing STL data generated from a three-dimensional CAD model at an equal pitch is used. At this time, it is preferable to irradiate the light beam L so that at least the outermost surface of the three-dimensional shaped object can be sintered so as to have a high density (porosity of 5% or less). This is because even if the surface removal described later is performed by the removing means 4, if the exposed portion is porous, the surface after the removal processing is also in a porous state. For this purpose, as shown in FIG. 3, the shape model data is divided in advance into a surface layer portion S and an inner portion N, and the inner N portion is sintered under a porous condition. Then, the light beam L is irradiated under the condition of high density. FIG. 4 shows the low-density surface layer 16 made of the high-density portion 12 and the above-mentioned adhered powder.

Here, the thickness of the powder layer 10 and the energy amount of the irradiated light beam L are set according to the tool diameter of the cutting tool 41. Specifically, when a cutting tool 41 having a tool diameter of 1.0 mm is used, it is preferable that the thickness Δt1 of the powder layer 10 is 0.05 mm and the energy amount of the light beam L is 10.0 J / mm ² . On the other hand, when the cutting tool 41 having a tool diameter of 0.5 mm is used, it is preferable that the thickness Δt1 of the powder layer 10 is 0.025 mm and the energy amount of the light beam L is 5.0 J / mm ² .

  Moreover, it is preferable to set also about the condensing diameter of the light beam L according to the tool diameter of the cutting tool 41. FIG. Specifically, when the cutting tool 41 having a tool diameter of 1.0 mm is used, the condensing diameter of the light beam L is preferably 0.6 mm. On the other hand, when the cutting tool 41 having a tool diameter of 0.5 mm is used, the condensing diameter of the light beam L is preferably 0.4 mm.

  Further, the particle size of the powder material is preferably set according to the tool diameter of the cutting tool 41. Specifically, when a cutting tool 41 having a tool diameter of 1.0 mm is used, the average particle diameter of the powder material is preferably 30 μm. On the other hand, when the cutting tool 41 having a tool diameter of 0.5 mm is used, 15 μm is preferable as the average particle diameter of the powder material.

  The thickness of the powder layer 10 and the amount of energy of the light beam L to be irradiated, the condensing diameter of the light beam L, and the particle size of the powder material are automatically controlled according to the tool diameter of the cutting tool 41. May be.

  Then, when the powder layer 10 is formed, the light beam L is irradiated and the sintered layer 11 is repeatedly formed. The total thickness of the sintered layer 11 is, for example, the tool length of the cutting tool 41. When the required value obtained from the above is reached, the removal means 4 is once activated to cut the surface of the modeled object that has been modeled so far. For example, when using a cutting tool 41 capable of cutting with a tool diameter of 1.0 mm, an effective blade length of 3.0 mm and a depth of 3.0 mm, the thickness Δt1 of the powder layer 10 is 0.05 mm. When the 60 sintered layers 11 are formed, the removing means 4 is operated.

  As shown in FIG. 4, the removal means 4 performs the cutting process to remove the low density surface layer 16 from the powder adhering to the surface of the modeled object, and at the same time, the high density part 12 is scraped to obtain a high density on the modeled object surface. The part 12 is exposed entirely. Thereby, the surface roughness of the modeled object surface can be increased. Therefore, the sintered layer 11 is made slightly larger than the desired shape M.

  The cutting path by the removing means 4 is created in advance from three-dimensional CAD data in the same manner as the irradiation path of the light beam L. At this time, the machining path is determined by applying 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, by interpolating with a finer Z-direction pitch, Keep a smooth surface. When cutting is performed with the cutting tool 41 having a tool diameter of 1 mm, the cutting depth is 0.1 to 0.5 mm, the feed rate is 5 m / min to 50 m / min, and the tool rotation speed is 20,000 rpm to 100,000 rpm. Is preferred.

  When removing by cutting, as shown in FIG. 5, the portion immediately before the cutting is softened by irradiating and heating the light beam L having a reduced energy density, and the softened portion is removed. When the cutting tool 41 performs cutting, the cutting resistance is reduced, so that the cutting time can be shortened and the life of the cutting tool 41 can be extended.

  In addition, as shown in FIG. 6, it is also preferable to increase the surface density by irradiating the light beam L again to the portion immediately after cutting and removing it by heat-curing or heat treatment.

  By the way, when removing the shaped article surface and unnecessary parts by the removing means 4, the unsintered powder and the cutting waste by the removing means 4 interfere with the removal work, and when the next powder layer 10 is formed, the blade 21 is cut. The flat powder layer 10 may not be formed due to scraps, or the blade 21 may stop due to the cutting scraps sandwiched between the blade 21 and the modeled object. For this purpose, as shown in FIG. 7 and FIG. 8 (a) or FIG. 8 (b), it is preferable to provide, for example, an exclusion means 5 comprising an air pump 50 and a suction nozzle 51. Here, the suction nozzle 51 connected to the air pump 50 may be disposed adjacent to the cutting tool 41 to suck the unsintered powder and the cutting waste simultaneously with the cutting. In the case shown in FIG. 8B in which the cutting tool 41 is surrounded by the suction nozzle 51, a spindle head can be preferably used for the cutting tool 41.

  As shown in FIG. 9, before cutting, only the unsintered powder may be sucked and collected, and the cutting waste may be sucked and removed simultaneously with the cutting process. This makes it easy to reuse the unsintered powder.

  By the way, when the unsintered powder has been collected by suction, a large amount of powder is required when the powder layer 10 is further laminated after the removal step. The lost space must be filled with powder, which increases time loss. For this reason, as shown in FIG. 10, a solidified portion 18 is formed by pouring a resin or brazing material into the space where the unsintered powder is eliminated, and solidifying the next powder layer 10. It may be formed on the upper surface of the binder layer 11 and the solidified portion 18. The amount of powder used can be reduced.

  As shown in FIG. 11, the suction nozzle 51 in the exclusion means 5 is attached to the drive portion of the blade 21 in the powder layer forming means 2 for sucking and collecting the unsintered powder prior to the removing step. In addition, it is possible to suck and collect the unsintered powder in the entire area and to eliminate the need for a dedicated drive mechanism for the suction nozzle 51, so that the apparatus configuration can be simplified.

  In addition, as shown in FIG. 12, when the suction nozzle 51 is attached to the dedicated XY drive mechanism 55 or the XY drive mechanism 40 in the removing means 4, the suction nozzle 51 is moved along the cross-sectional contour shape of the modeled object. Can be moved.

  For the unsintered powder, it is not sucked and collected before the removal process, but the unsintered powder is frozen by, for example, spraying liquid nitrogen or the like (if necessary, simultaneously containing gas containing moisture). The removing means 4 may be operated in this state by solidifying or pouring a resin or brazing material. Since the cutting waste does not enter the unsintered powder, only the cutting waste can be easily sucked out without requiring refilling of the powder.

  What is shown in FIG. 13 is provided with measuring means 6 for measuring the shape and position of a shaped article immediately after sintering or immediately after removal processing. Light beam irradiation accuracy and removal processing accuracy can be measured on-machine. The measurement result (positional coordinate data) and CAD data are compared by feeding back the measurement results. In addition to being able to calculate, the next light beam irradiation path data is corrected or the next removal processing path data is corrected based on the comparison result, thereby enabling more accurate modeling.

  When the measuring means 6 is, for example, a piezoelectric contact sensor, if the measuring means 6 is provided in the XY drive mechanism 40 in the removing means 4, the measurement can be performed without requiring a dedicated drive mechanism for the measuring means 6. It can be carried out.

  Further, as the measuring means 6, an imaging means such as a CCD camera may be used. The imaging means is moved so that the point to be measured is the center of the image, and the amount of deviation is measured from the number of pixels that are shifted between the center of the image and the point to be measured in the modeled object.

  Note that the removed portion is not limited to the surface portion of the modeled object. For the sake of modeling, if an unnecessary part must be modeled, the unnecessary part can be removed.

  Therefore, by setting the coating thickness of the powder material and the energy amount of the light beam L to be irradiated according to the tool diameter of the cutting tool 41 used in the removing process, the amount of unnecessary powder that adheres to the surface of the modeled object Can be set to an amount corresponding to the tool diameter of the cutting tool 41, so that it is possible to efficiently perform the cutting and removing process, and as a result, a three-dimensional shaped article having a good surface appearance is produced in a short time. be able to.

  Further, by setting the condensing diameter of the light beam L according to the tool diameter of the cutting tool 41 used in the removal process, the amount of unnecessary powder adhering to the surface of the modeled object is set to the tool diameter of the cutting tool 41. Since it can set to the quantity according to, a three-dimensional shape molded article can be manufactured still more efficiently.

  And according to the tool diameter of the cutting tool 41 used at a removal process, the particle size of the powder to coat | cover is set to the tool diameter of the cutting tool 41 by setting the particle diameter of the powder to coat | cover. Since it can set to the particle size according to, a three-dimensional shaped molded article can be manufactured more efficiently.

  In particular, when the cutting tool 41 having a small tool diameter is used, the particle size of the powder material to be coated is made fine, the powder thickness to be coated is made thin, and the irradiation energy amount of the light beam when forming the sintered layer By reducing the diameter and reducing the light condensing diameter, it is possible to efficiently produce a three-dimensional shaped object and to reduce the breakage of the cutting tool 41.

  In addition, since the powder material contains metal powder with a small particle size, the surface area of the powder material is increased and the absorption rate of the light beam L is increased, so that the powder material is easily sintered even under irradiation conditions with low energy density. Increases speed. Further, in order to obtain a certain degree of modeling strength, it is necessary to increase the adhesion strength between the adjacent sintered layers 11. The binder layer 11 is also irradiated, and the lower sintered layer 11 is heated to improve the adhesion strength.

It is a schematic perspective view which concerns on an example of embodiment of this invention. It is operation | movement explanatory drawing same as the above. It is explanatory drawing regarding the surface high-density part same as the above. It is sectional drawing which shows the removal process same as the above. It is a perspective view which shows operation | movement of the other example same as the above. It is a perspective view which shows operation | movement of the further another example same as the above. It is a schematic perspective view of the other example same as the above. It is a schematic sectional drawing which shows an example of an exclusion means. It is a schematic sectional drawing which shows operation | movement of the other example of an exclusion means. It is a schematic sectional drawing which shows the process after exclusion. It is a schematic sectional drawing which shows the other example of an exclusion means. It is a schematic perspective view which shows the further another example of an exclusion means. It is a schematic perspective view of the example provided with the measurement means.

Explanation of symbols

4 Removal means 10 Powder layer 11 Sintered layer 41 Cutting tool L Light beam

Claims (4)

A predetermined layer of the powder material layer is irradiated with a light beam to sinter the powder at the corresponding portion to form a sintered layer, and a new layer of the powder material is coated on the sintered layer to cover the predetermined portion. A plurality of sintered layers are laminated and integrated by repeating the formation of a new sintered layer that is integrated with the lower sintered layer by irradiating the light beam to the powder and sintering the powder at the corresponding location. In manufacturing a three-dimensional shaped object
In the method for producing a three-dimensional shape shaped article, including a removal step of removing at least one of the surface portion or unnecessary portion in the shaped article produced so far after the formation of the sintered layer, the removing step is a cutting process.
In the removal process, the smaller the tool diameter of the cutting tool to be used, the smaller the coating thickness of the powder material supplied to form the sintered layer and the smaller the amount of energy of the irradiated light beam, the three-dimensional A method of manufacturing a shaped object. In removal step, as the tool diameter of the cutting tool to be used is small, method of manufacturing a three-dimensionally shaped object according to claim 1, characterized in that also set smaller condensing diameter of the light beam. In removal step, as the tool diameter of the cutting tool to be used is small, the manufacturing method of three-dimensionally shaped object according to claim 1 or 2, characterized in that to set the particle size of the powder to further coating is small. The method for producing a three-dimensional shaped article according to any one of claims 1 to 3 , wherein the powder material contains a metal powder.

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