JP2007217230A - Inorganic and organic bonding powder for sintering and molding, and pump part and pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic and organic bonding powder for sintering and molding which enhances bonding strength among aggregate with a small amount of an organic material, gives sufficient strength and stiffness and hardly generates growth defects; and also to provide a pump part and a pump device. <P>SOLUTION: The inorganic and organic bonding powder for sintering and molding is constituted by coating aggregate 1, comprising spherical or bulk powder of an inorganic compound, with a solvent-soluble thermoplastic organic material 3. The inorganic compound is constituted of an oxide, a carbide or a nitride and has a particle diameter of 10-150 μm, and the particle coated with the thermoplastic organic material has a particle diameter of 20-200 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inorganic / organic binder powder suitable for use in sintering and molding, and a pump component and a pump device molded using the powder.

  Conventionally, a molded product is fired and molded by a selective laser sintering apparatus (SLS). That is, for example, as shown in FIG. 3, in a chamber 132 of a selective laser sintering apparatus 130, a thermoplastic organic material powder produced by a mechanical pulverization method is used for an aggregate made of a spherical or lump powder made of an inorganic compound. A powdery material obtained by mixing is supplied to form a particle layer 134 having a thickness h of, for example, 0.1 mm. Then, the particle layer 134 is irradiated with laser light from a laser light source 136 such as a carbon dioxide laser generator through a mirror 138, and the organic material located in the portion irradiated with the laser light is selectively melt-cured (sintered). And the flakes 140 are formed. Thereafter, this process is repeated, and the thin pieces 140 are sequentially laminated to form a predetermined shape. In other words, a three-dimensional molded product was manufactured by a lamination method using an organic material as an aggregate binder.

  The molded product molded as described above is a porous body and may be used as a structure as it is, or when the molded product made of this porous body is impregnated with urethane resin or epoxy resin and used. There are also cases where the porous material is impregnated with ethyl silicate and subjected to a firing secondary treatment to convert the organic material and ethyl silicate into an inorganic material for use as a structure or a mold material for precision casting. In either case, physical properties corresponding to the application are required.

For example, in the case of structures such as pump impellers and casings, strength, rigidity, or toughness is required, and usually an organic material such as polyamide is combined with an aggregate such as SiO ₂ or Al ₂ O _3. To use. In the case of the mold material, the content of the organic material used as the caking material must be reduced as much as possible in order not to lower the fire resistance of the heat-resistant material.

However, the conventional example has the following problems.
(1) When there were few organic materials compared with aggregate, sufficient mixing was difficult and sufficient intensity was not obtained.

(2) It did not function as a binding material unless the proportion of the organic material was increased compared to the aggregate.

(3) When there are more organic materials than aggregates, the mixed powdered aggregate and the powdered organic material will have a portion with a lot of organic material and a portion with a small amount of organic material. Later, sufficient rigidity was not obtained.

(4) In order to prevent the sintered portion (slice 140) from being deformed by pressing a portion where only the sintered portion to which the laser is applied is thermally expanded and is not thermally expanded in the modeling process by the laser, the entire particle layer 134 Is preheated (a little lower than the sintering temperature, for example, about 170 ° C. when the laser sintering temperature is 187 ° C.), but the organic material pulverized powder and aggregate prepared by the mechanical pulverization method As described above, there are a large part and a small part of the organic material in the mixture, so that the adjacent organic materials in the part with a large amount of organic material are easily stuck to each other by the heating. When the size of the material increases, the part of the organic material that is not irradiated with the laser near the laser irradiation range aggregates and adheres to the part to be sintered by the laser. So-called gross defects become fat structure than the sintering shape (shape of the portion irradiated with laser) is may occur.

(5) In the laser molding process, the part not irradiated with the laser (non-sintered part) remains in powder form and is reused for forming the particle layer. However, as described above, since the entire particle layer 134 is heated to a temperature close to the sintering temperature in advance, adjacent organic materials grow in a portion where a large amount of organic material is present, and the surface of the grown organic material surface is grown. The contact area is smaller than the contact area of a plurality of organic materials before sticking, and therefore, the temperature required for firing at the time of reuse increases, and the laser power has to be increased.

(6) Since the organic material is pulverized by a mechanical pulverization method, the number of particles having a particle size other than the required range is increased, and this problem is particularly increased in the case of a soft material such as a thermoplastic material. The recovery rate as a powder for sintering and molding was poor.
Japanese Patent Laid-Open No. 2004-90046

  The present invention has been made in view of the above-mentioned points, and its purpose is to obtain a sufficient strength and rigidity by strengthening the bonding force between aggregates with a small amount of organic material, and to prevent the occurrence of gross defects. An object of the present invention is to provide an inorganic-organic bonding powder for molding, a pump component, and a pump device.

  The invention according to claim 1 of the present invention is an inorganic organic bonded powder for sintering and molding, characterized in that a solvent-soluble thermoplastic organic material is coated on an aggregate made of a spherical or block powder made of an inorganic compound. is there. As a result, the powders can be easily bonded to each other with a small amount of organic material.

  That is, if the thermoplastic organic material 3 is thinly coated on the surface of the aggregate 1 as shown in FIG. 1, the thermoplastic organic material 3 on the surface of the aggregate 1 is in direct contact with each other, so that the wettability between the powders is good and firing is performed. In this case, sufficient bond strength can be obtained with a small amount of organic material. In addition, only the powder of the organic material is not bonded to each other as in the above conventional example, and when the organic material is bonded, the aggregate is also bonded, so that the portion with a lot of the organic material and the portion with a small amount are made uniform, Sufficient rigidity is obtained. Similarly, there are no parts with a lot of organic material and parts with little organic material, so the parts around the part irradiated with the laser do not bond to the sintered part irradiated with the laser and become a fat structure, and gross defects occur. It becomes difficult. Similarly, there are no parts with a lot of organic material and parts with little organic material, so in the modeling process by laser, when the whole particle layer is heated, the powder of only the organic material adjacent to each other in the part with a lot of organic material grows. Therefore, it is not necessary to increase the laser power when the powder is reused.

  A liquid pulverization method is preferably used for coating the surface of the aggregate with the thermoplastic organic material. Here, the liquid pulverization method (chemical pulverization method) is a method in which the thermoplastic organic material is dissolved in a solvent, and then the aggregate is put in the solvent and stirred while being pressurized and heated to evaporate the solvent, thereby causing bone It is a manufacturing method for obtaining a powder in which a thermoplastic organic material is nucleated on the material surface. According to this method, even a soft thermoplastic organic material can be easily thinly coated on the aggregate surface.

  When the thermoplastic organic material is coated on the surface of the aggregate by the liquid pulverization method, as shown in FIG. 1, the surface of the aggregate 1 is not coated with the thermoplastic organic material 3 independently. Alternatively, as shown in FIG. 2, a plurality of aggregates 1 may be taken into one organic material block 3-1. Even if it does in this way, since the whole surface of the block 3-1 can be made of the same organic material, the wettability between the powders remains good and the bonding force does not decrease.

  The molded product formed by firing the inorganic organic binder powder for sintering / molding may be a product (structure) or a casting mold, and its application fields are diverse.

  The invention according to claim 2 of the present application is such that the inorganic compound is composed of an oxide, a carbide or a nitride, has a particle size of 10 to 150 μm, and is coated with a thermoplastic organic material. 2. The inorganic / organic binder powder for sintering and molding according to claim 1, wherein the particle size of the binder powder is 20 to 200 [mu] m. When the particle size of the inorganic / organic bonding powder for sintering / molding is set to 20 μm or more when the particle layer 134 is provided in the selective laser sintering apparatus 130 shown in FIG. 3, the selective laser sintering apparatus is used. This is because the inside of 130 is purged with nitrogen, so that the powder constituting the particle layer 134 is likely to rise by the flow of nitrogen gas and may clog the filter. Moreover, the reason why the particle size of the inorganic / organic bonding powder for sintering / molding is set to 200 μm or less is that the dimensional accuracy of the inorganic / organic bonding powder for sintering / molding is deteriorated when the particle diameter is increased.

The oxide is preferably SiO ₂ , Al ₂ O ₃ , Zr ₂ O ₃ or the like, the carbide is preferably SiC or TiC, and the nitride is preferably Si ₃ N ₄ or the like.

  Examples of the thermoplastic organic material include ABS resin, polyamide resin, polystyrene resin, acrylic resin, phenol resin, silicone resin, low density polyethylene (LDPE), polyamide (PA), polyethylene terephthalate (PET), polyethersulfone (PES). ), Polypropylene (PP), polyimide (PI), polybutylene terephthalate (PBT), or polycarbonate (PC).

  In the invention according to claim 3, the mixing ratio of the aggregate and the thermoplastic organic material is expressed by weight% in accordance with the physical properties required for the use, and (aggregate) :( thermoplastic organic material) = 99. The inorganic / organic binder powder for sintering / molding according to claim 1, wherein the inorganic organic binder powder is 1 to 50:50. The thermoplastic organic material is used as a binder for the aggregate, but the reason why the thermoplastic organic material is set to 1 or more with respect to the aggregate 99 is the limit amount that can form this inorganic organic binder powder for sintering and molding. That's why (it can only be formed with aggregate and without binder). The reason why the thermoplastic organic material is 50 or less with respect to the aggregate 50 is that the thermoplastic organic material as a binder is buried between the aggregate and the aggregate, but the mixing ratio of this thermoplastic organic material is This is because the limit of the mixing ratio at which the aggregates contact each other is to maintain strength. If the aggregates do not touch each other, the strength of the binder is increased and the strength is reduced.

  Invention of Claim 4 of this application exists in the pump component characterized by shape | molding by baking the inorganic organic combined powder for sintering and shaping | molding of Claim 1 or 2 or 3.

  The invention according to claim 5 of the present application is a pump device comprising the pump component according to claim 4.

  According to the first aspect of the present invention, even a small amount of organic material can strengthen the bonding force between the aggregates to obtain sufficient strength and rigidity, and a molded article having stable physical properties can be formed. In addition, gross defects are less likely to occur during the laser modeling process. Further, it is not necessary to increase the laser power when reusing the powder of the non-sintered portion that was not irradiated with the laser in the modeling process using the laser. In addition, a powder having a required particle size can be easily obtained as the powder for the selective laser sintering apparatus, the recovery rate thereof is good, and the powder for the selective laser sintering apparatus can be obtained at a low cost.

  According to the second aspect of the present invention, modeling by a laser of the selective laser sintering apparatus can be easily and accurately performed.

  According to the invention described in claim 3 of the present application, the physical properties required depending on the use of the molded product obtained by firing and molding the inorganic organic binder powder for sintering and molding can be obtained.

  According to the invention described in claim 4 of the present application, various pump parts such as an impeller and a casing can be configured using the inorganic / organic bonding powder for sintering and molding according to the present invention.

  According to the invention described in claim 5 of the present application, the pump device can be configured using the component described in claim 4.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Embodiment 1] An example of making a powder for a structure using SiO ₂ as an aggregate and polyamide as a thermoplastic organic material (1) Raw material composition SiO ₂ powder: particle size range: 30 to 100 μm, shape : Spherical, mixing ratio: 50% by weight
Polyamide (nylon 22) ... Mixing ratio: 50% by weight
(2) Manufacturing method Polyamide is dissolved in an aromatic solvent, and SiO ₂ powder is added and stirred in an autoclave (heating / pressurizing kettle) while heating and pressing to evaporate the solvent to obtain a powder according to the first embodiment. It was.
(3) Powder particle size range: 50-150 μm
(4) Characteristics of Molded Product Using Powder According to Embodiment 1 A structure (vertical × horizontal × height = 55 mm × 10 mm × 5 mm rectangular parallelepiped used for JIS test) using a selective laser sintering apparatus using the powder Shape structure) was manufactured, and its tensile strength test and elongation (toughness) test were conducted. The results are shown below.
Tensile strength: 60 MPa
Elongation (toughness): 5%

Comparative Example 1 using SiO ₂ as an aggregate, example of creating a structure for powder using polyamide as the thermoplastic organic material (1) Raw material constituting SiO ₂ powder ... size range: 30 to 100 [mu] m, the shape : Spherical, mixing ratio: 50% by weight
Polyamide (nylon 22) ... Mixing ratio: 50% by weight
(2) to obtain a powder of Comparative Example 1 by mixing those ground to the SiO ₂ powder by mechanical pulverization method a manufacturing method polyamides.
(3) Characteristics of molded product using powder according to Comparative Example 1 Using the powder, a structure (a rectangular parallelepiped structure having the same dimensions as those used in the JIS test) was produced by a selective laser sintering apparatus. The tensile strength test and the elongation (toughness) test were conducted. The results are shown below.
Tensile strength: 50 MPa
Elongation (toughness): 2%

  As can be seen from Embodiment 1 and Comparative Example 1 above, the structure manufactured using the powder according to Embodiment 1 is stronger and tougher than the structure manufactured using the powder according to Comparative Example 1. It was found that both were excellent. Therefore, it is suitable for various structures such as a pump impeller and casing.

[Embodiment 2] Example of making powder for mold material using Zr ₂ O ₃ as aggregate and silicone resin as thermoplastic organic material (1) Raw material composition Zr ₂ O ₃ powder ... Particle size range : 30 to 100 μm, shape: spherical, mixing ratio: 95% by weight
Silicone resin ... Mixing ratio: 5% by weight
(2) Production Method A silicone resin varnish was dissolved in MEK (methyl ethyl ketone), Zr ₂ O ₃ powder was added, and the mixture was stirred while heating and pressurizing in an autoclave, and the solvent was evaporated to obtain a powder according to Embodiment 2.
(3) Powder particle size range: 50-150 μm
(4) Characteristics of molded product using powder according to embodiment 2 Using the powder, a structure (a rectangular parallelepiped structure having the same dimensions as those used in the JIS test) is manufactured by a selective laser sintering apparatus. A compression strength test was conducted. The results are shown below.
Compressive strength: 60 kg / cm ²

[Comparative Example 2] Example of making powder for mold material using Zr ₂ O ₃ as aggregate and using silicone resin as thermoplastic organic material (1) Raw material composition Zr ₂ O ₃ powder ... Particle size range : 30 to 100 μm, shape: spherical, mixing ratio: 95% by weight
Silicone resin ... Mixing ratio: 5% by weight
(2) those that the manufacturing process silicone resin was ground by mechanical grinding method to obtain a powder according to Comparative Example 2 by mixing a powder of Zr ₂ O _3.
(3) Characteristics of molded product using powder according to Comparative Example 2 Using the powder, a structure (a rectangular parallelepiped structure having the same dimensions as those used in the JIS test) was produced by a selective laser sintering apparatus. A compression strength test was conducted. The results are shown below.
Compressive strength: 50 kg / cm ²

  As can be seen from Embodiment 2 and Comparative Example 2 above, it can be seen that the mold manufactured using the powder according to Embodiment 2 is superior in strength to the mold manufactured using the powder according to Comparative Example 2. It was.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible.

1 is an enlarged schematic view of an inorganic organic binder powder for sintering and molding in which a surface of an aggregate 1 is coated with a thermoplastic organic material 3. FIG. 1 is an enlarged schematic view of an inorganic organic binder powder for sintering / molding in which a surface of an aggregate 1 is coated with a thermoplastic organic material 3-1. It is the schematic which shows the selective laser sintering apparatus 130. FIG.

Explanation of symbols

1 Aggregate 3 Thermoplastic organic material 3-1 Thermoplastic organic material (block)
130 Selective Laser Sintering Device 132 Chamber 134 Particle Layer 136 Laser Light Source 138 Mirror 140 Flakes

Claims (5)

  An inorganic / organic bonding powder for sintering / molding, characterized in that a solvent-soluble thermoplastic organic material is coated on an aggregate made of a spherical or massive powder made of an inorganic compound.   The inorganic compound is composed of oxide, carbide, or nitride, and has a particle size of 10 to 150 μm. Further, the particle size of the inorganic organic bonding powder for sintering / molding coated with a thermoplastic organic material is 20 to 200 μm. The inorganic / organic binder powder for sintering and molding according to claim 1.   2. The inorganic / organic bonding powder for sintering and molding according to claim 1, wherein a mixing ratio of the aggregate and the thermoplastic organic material is 99: 1 to 50:50 in terms of% by weight.   A pump part formed by firing the inorganic / organic bonding powder for sintering / molding according to claim 1, 2 or 3. A pump device comprising the pump component according to claim 4.

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