JP4888220B2 - Manufacturing method of three-dimensional shaped object - Google Patents

Description

  The present invention relates to a method for manufacturing a three-dimensional shaped object that irradiates a metal powder with a light beam.

  Conventionally, a light beam is irradiated onto a powder layer formed of metal powder, the powder layer is melted to form a sintered hardened layer, a new powder layer is formed on the sintered hardened layer, and the light beam is irradiated. A method of manufacturing a three-dimensional shaped object by repeating irradiation and forming a sintered hardened layer is known (for example, see Patent Document 1).

  Thus, the manufacturing method for obtaining a three-dimensional shaped object from metal powder by irradiation with a light beam and its lamination can quickly obtain a complicated three-dimensional shaped object.

However, when the three-dimensional modeled object obtained by this manufacturing method is used as, for example, a plastic mold, various machining processes such as processing a through hole for an ejector pin are added after the modeling is completed. In this manufacturing method, a powder layer made of a metal powder is laid on a modeling plate as a base, a sintered hardened layer is formed by irradiating the powder layer with a light beam, and the sintered hardened layer is laminated. In order to improve the adhesion between the modeling plate and the three-dimensional modeled object, the first layer is modeled under a high-energy light beam condition. When receiving a high energy light beam, the surface of the modeling plate made of a steel material is hardened as a structure quenched by rapid heating and quenching in the vicinity of the portion irradiated with the light beam, resulting in a hardness difference in the modeling plate. Therefore, if drilling or turning with a lathe is performed on a hardened part after modeling is complete, drill tip breakage, drill shank breakage, bite tip breakage, etc. are likely to occur. Have difficulty.
JP-T-1-502890

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a method for manufacturing a three-dimensional shaped object that can be easily machined after the three-dimensional shaped object is formed. And

In order to achieve the above object, the invention of claim 1 includes a powder layer forming step of forming a powder layer by supplying metal powder to a modeling plate on which a three-dimensional shaped object is modeled, and a light beam on the powder layer. Irradiation step of melting the powder layer to form a sintered hardened layer, and repeating the powder layer forming step and the irradiation step to laminate the sintered hardened layer to form a three-dimensional shaped object. In the manufacturing method of a three-dimensional shaped object for modeling a predetermined machine after three-dimensional shape modeling in a first region corresponding to a cured layer of the modeling plate that will be cured by performing the irradiation step A removal process step in which a second region corresponding to a region scheduled for processing is removed in advance before the three-dimensional shape modeling, and after the three-dimensional shape modeling, the second region in the modeling plate Front from the other side Until a removal by removing processing step regions, it is intended to include, and machining steps of performing a predetermined machining.

  According to a second aspect of the present invention, in the method for manufacturing a three-dimensional shaped article according to the first aspect, after the removal processing step removes the second region, the edge portion of the first region is further removed. And chamfering.

  According to the first aspect of the present invention, the second region that is machined after the three-dimensional shape modeling is removed in advance before modeling out of the first region that is cured in the modeling plate. There is no cured portion in the area where machining is performed, and therefore machining after shaping can be performed easily.

  According to the invention of claim 2, since the edge portion of the first region is removed, the heat at the time of irradiation with the light beam easily escapes, and the modeling plate is not abnormally heated, and the modeling plate is not cracked.

(First embodiment)
A method for manufacturing a three-dimensional shaped object according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a metal stereolithography machine used in the manufacturing method. The metal stereolithography machine 1 includes a modeling plate 3 on which a powder layer 21 of a metal powder 2 is laid, a modeling table 31 that holds the modeling plate 3 and moves up and down, and a reference for the thickness of the powder layer 21. The reference table 32, the supply tank 4 for supplying the metal powder 2, the material table 41 for raising the metal powder 2 in the supply tank 4, the squeegee 5 for forming the powder layer 21, and the beam for emitting the light beam L A transmitter 6, a condensing lens 61 that condenses the light beam L, and a galvanometer mirror 62 that scans the light beam L onto the powder layer 21 are provided.

  The composition of the metal powder 2 is, for example, chromium molybdenum steel (JIS-SCM440) powder, nickel (Ni) powder, copper manganese alloy (CuMn) powder, and graphite (C) powder, and the blending ratio is, for example, 70 wt. 0.3% by weight of graphite (C) powder is added to the powder of% SCM440, 20% by weight Ni, and 10% by weight CuMn. The material of the modeling plate 3 is, for example, S50C steel, and the hardness is HRC20. The squeegee 5 moves in the direction A and supplies the metal powder 2 on the material table 41 onto the modeling plate 3. The beam transmitter 6 is, for example, a carbon dioxide laser or fiber laser transmitter.

  FIG. 2 shows a flow of the manufacturing method, and FIG. 3 shows an operation of the manufacturing method. First, a part of the portion irradiated with the light beam in the modeling plate 3 is removed (step S1). The part to be removed is scheduled to be subjected to predetermined machining after three-dimensional shape modeling within the region of the cured layer of the modeling plate 3 that will be cured by irradiation with a light beam in a later irradiation step. This is an area corresponding to the area. This step S1 constitutes a removal process. Details of this removal step will be described later. Following the removing step, the modeling plate 3 is placed on the modeling table 31 (step S2). Next, the modeling table 31 is lowered so that the level difference between the upper surface of the modeling plate 3 and the upper surface of the reference table 32 becomes the length Δt (step S3). Next, the metal powder 2 on the material table 41 is supplied onto the modeling plate 3 by the squeegee 5. The squeegee 5 moves in the horizontal direction at the same height as the upper surface of the reference table 32, and forms a powder layer 21 having a thickness Δt on the modeling plate 3 (step S4) (see FIG. 3A). Steps S3 and S4 constitute a powder layer forming process.

  Next, the light beam L condensed by the condenser lens 61 is scanned to an arbitrary position by the galvanometer mirror 62 (step S5), and the powder layer 21 is melted and integrated with the modeling plate 3 to be sintered and cured with a thickness Δt. The layer 8a is formed (step S6) (see FIG. 3B). Steps S5 and S6 constitute an irradiation process.

  Next, it is determined whether or not the shaping has been completed (step S7). If it has not been completed, the process returns to step S3, and steps S4, S5, and S6 are repeatedly executed to sinter harden on the sintered hardened layer 8a. The layer 8b is stacked (see FIGS. 3C and 3D).

  Steps S3 to S7 are repeated until the modeling is completed in this manner, thereby stacking the sintered hardened layers 8a to 8f (see FIG. 3E). FIG. 4 shows an example of the three-dimensional shaped object 8 that is formed on the modeling plate 3 in this way.

  Next, path data for scanning the light beam L will be described. FIG. 5A shows the appearance of the product model to be manufactured by three-dimensional shape modeling, and FIG. 5B shows the shape of the slice plane in the horizontal direction of the product model. In manufacturing a three-dimensional shaped object, based on the three-dimensional CAD data when the product model 81 is designed, the slice surface of each layer 81a to 81f when the product model 81 is horizontally sliced at a predetermined interval Δt. Cross-sectional data is created, and the scanning path of the light beam L that irradiates the powder layer 21 is determined based on the cross-sectional data. By scanning the powder layer 21 with the light beam L according to the determined scanning path, the three-dimensional shaped object 8 can be formed.

  Next, before explaining the removal process in the present embodiment, an example of an operation for performing machining on a three-dimensionally shaped object formed by a conventional manufacturing method that does not have a removal process will be described. FIG. 6A shows a cross section of a three-dimensional shaped object that is formed on the modeling plate 3. In this example, the three-dimensional shaped article 8 has an ejector pin hole 82 formed in the center, and a hole connected to the hole 82 is formed in the modeling plate 3. The region where the modeling plate 3 is joined to the three-dimensional modeled object 8 is irradiated with a high-energy light beam L in order to improve the adhesion to the three-dimensional modeled object 8 in the irradiation process, and is rapidly quenched. It becomes a hardened structure and is a hardened region. This area is referred to as a first area E1. Within this first region E1, a region corresponding to a region where drilling is scheduled after the three-dimensional shape formation is defined as a second region E2.

  FIG. 6B shows a cross section of the three-dimensional modeled article 8 when the modeling plate 3 is drilled. When the drill F is used to drill a hole in the modeling plate 3 that is connected to the hole 82 of the three-dimensional modeled article 8, the second area is reached when the tip of the drill F reaches the second area E <b> 2 of the modeling plate 3. Since there is a difference in hardness between E2 and other regions, the cutting edge of the drill F may be lost or the drill shank may be broken.

  Therefore, in the present embodiment, the second region E2 is removed in advance before modeling in order to facilitate the drilling process after the three-dimensional shape modeling. FIG. 6C shows a cross section of the modeling plate 3 from which the second region E2 has been removed by the removing step in the present embodiment. The removal is performed by cutting, for example. FIG. 6D shows a cross section of the three-dimensional shaped article 8 using the modeling plate 3 from which the second region E2 has been removed when the modeling plate 3 is punched after modeling. In this figure, the region where the drilling process is performed is indicated by a one-dot chain line G. In the modeling plate 3, the second region E2 is removed, and there is no hardened portion in the region where the drilling process is performed after the modeling. Accordingly, even if the hole forming process is performed on the modeling plate 3, the cutting edge of the drill F does not hit the hardened portion, and the cutting edge is less likely to break or the drill shank is broken. be able to. The second region E2 removed in this way is not limited to a region where drilling is performed after the three-dimensional shape modeling, but may be a region where machining such as turning or cutting is performed.

(Second Embodiment)
A method for manufacturing a three-dimensional shaped object according to the second embodiment of the present invention will be described. In the manufacturing method according to the present embodiment, after removing the second region E2 in the manufacturing method of the first embodiment, chamfering around the removed region is performed (see FIG. 6C). FIG. 7 (a)
The cross section of the three-dimensional shape molded article manufactured by the manufacturing method of 1st Embodiment is shown. The edge portion E3 of the surrounding modeling plate 3 from which the second region E2 has been removed has a tip that protrudes in a right-angled shape. Due to the change in toughness, the toughness is lowered and cracks are likely to occur. Therefore, in the present embodiment, as shown in FIG. 7B, after the second region E2 is removed, the peripheral edge portion E3 is chamfered. The edge portion E3 is chamfered, and there is no portion that is abnormally heated when the light beam is irradiated. The periphery where the second region E2 is removed does not have a protruding region, and heat at the time of irradiation with the light beam easily escapes and does not abnormally heat. Therefore, the toughness is not lowered due to the change of the metal structure, and cracks are hardly generated. Become.

  In addition, this invention is not restricted to the structure of the said various embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, the removal of the second region E2 may be performed by etching. Further, the composition of the metal powder and the material of the modeling plate are not limited to the configurations of the various embodiments.

The perspective view of the metal stereolithography processing machine used for the manufacturing method which concerns on the 1st Embodiment of this invention. The flowchart of the manufacturing method. (A) thru | or (e) is a figure explaining the manufacturing method in time series. The perspective view of the three-dimensional shape modeling thing modeled by the manufacturing method. (A) is a perspective view of a product model to be manufactured by the manufacturing method, (b) is a diagram showing a horizontal slice surface of the product model. (A) is a cross-sectional view of a three-dimensional shaped object by a conventional manufacturing method, (b) is a cross-sectional view when drilling a three-dimensional shaped object by the same manufacturing method, and (c) is a first embodiment. Sectional drawing of the plate for modeling in the manufacturing method which concerns on a form, (d) is sectional drawing of the three-dimensional shaped molded object by the manufacturing method. (A) is sectional drawing of the three-dimensional molded object by the manufacturing method which concerns on 1st Embodiment, (b) is sectional drawing of the plate for modeling in the manufacturing method which concerns on 2nd Embodiment.

Explanation of symbols

2 Metal powder 21 Powder layer 3 Modeling plate 8 Three-dimensional modeled object 8a to 8f Sintered hardened layer E1 1st area | region E2 2nd area | region E3 Edge part L Light beam

Claims (2)

A powder layer forming step of forming a powder layer by supplying metal powder to a modeling plate on which a three-dimensional shaped object is formed, and a sintered hardened layer by irradiating the powder layer with a light beam to melt the powder layer In the manufacturing method of a three-dimensional shaped article, the three-dimensional shaped article is formed by laminating the sintered hardened layer by repeating the powder layer forming step and the irradiation step.
Of the first region corresponding to the cured layer of the modeling plate that will be cured by performing the irradiation step, the second region corresponding to the region where predetermined machining is scheduled after the three-dimensional shape modeling The removal processing step of removing the region in advance before the three-dimensional shape modeling ,
And a machining step for performing predetermined machining until reaching the area removed in the removing process step from the opposite side of the second area in the modeling plate after the three-dimensional shape modeling. A manufacturing method of a three-dimensional shaped object.   The three-dimensional shaped object according to claim 1, wherein the removing step includes a step of chamfering the edge portion of the first region after removing the second region. Manufacturing method.

Images