KR100583786B1 - Powders for selective laser sintering manufacturing method thereof and selective laser sintering method using the same - Google Patents

Abstract

The present invention relates to a polymer powder for selective laser sintering, a method of manufacturing the same, and a selective laser sintering using the rapid molding machine directly from a three-dimensional CAD data. In the molding method, the polymer powder for selective laser sintering molding according to the present invention is mixed with one or more fine particles selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles in spherical polymer beads having a particle diameter of 1 to 100 μm. have. Since the polymer powders used in the selective laser sintering molding method of the present invention are spherical beads having a fine size, the surface smoothness of the laser sintered prototype is good using the same, so that the fine particles are incorporated into the polymer powder. Since it is uniformly dispersed in the prototype to reinforce the strength of the prototype, it can be usefully used as a prototype of a mass production product that requires strength.

Description

Polymer powder for selective laser sintering molding, manufacturing method thereof and selective laser sintering, manufacturing method etc. and selective laser sintering method using the same}

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a schematic cross-sectional view of a polymer powder for selective laser sintering molding in which fine particles are mixed in spherical polymer beads according to the present invention,

2 is a schematic cross-sectional view of a polymer powder for selective laser sintering molding in which a metal coating layer is formed on a spherical polymer bead surface according to the present invention;

3 is an optical micrograph of a polymer powder for selective laser sintering molding prepared according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1 .... polymer beads 2 .... particulates

3 .... metal coating layer 10 ... polymer powder

The present invention relates to a polymer powder for selective laser sintering, a method of manufacturing the same, and a selective laser sintering using the rapid molding machine directly from a three-dimensional CAD data. It is about molding method.

When manufacturing injection molds used in various fields such as automotive, electronics, aviation, etc., prototypes are generally manufactured for design errors and design verification in the early stages of product development. Prototypes are mainly manufactured using materials that are easy to process, such as wood and plastic, which takes a lot of time and money, and has the disadvantage of not being able to accurately process freeform surfaces.

To overcome this limitation, Rapid Prototyping (RP) is used at the design stage. Rapid Prototyping (RP) is a method that can be used directly from 3D CAD data using various non-metallic and metal materials such as paper, wax, and polymers. It refers to a method of rapidly forming a dimensional prototype or mold immediately.

The rapid molding method is largely used to produce a three-dimensional shape by irradiating and curing a liquid material with a laser beam, and a method of joining granular or layered solid materials into a desired shape. It can be divided into two.

First, one of the above-mentioned curing methods (stereolithography, SLA; 3D Systems Co., Ltd.) continuously stacks one by one by selectively irradiating and solidifying a laser beam onto a liquid photopolymer. That's the way. Such optical molding method is a method of irradiating a laser beam locally (3D Systems-SLA, Quadrax, Sony, Dupont, etc.) and a method of irradiating one layer at a time by using an ultraviolet lamp (Cubital-SGC, There are two ways: Light Sculpting. However, this photoforming method has a disadvantage in that the cured photocurable resin shrinks during curing and a warping phenomenon occurs. In addition, when manufacturing a product having a protrusion, there is a disadvantage that a support for supporting the photocurable resin used to form such a protrusion does not fall down is required. In addition, since only the resin is used as a constituent material, there is a disadvantage that it is difficult to use as a functional material due to its low strength.

In addition, laminated object manufacturing (LOM; Helisys) manufactures a product by repeating a process of bonding a thin sheet of paper using a heated roller and cutting it with a laser. However, such a laminate material lamination method has the advantage that the operating cost is low because paper is used as a material, but has a disadvantage that it takes a lot of time to remove the product after manufacturing the product.

On the other hand, methods for producing shapes using powder materials include three-dimensional printing (three-dimensional printing; Solingen, Z Corp., etc.-MIT development) and selective laser sintering (SLS; DTM) Etc.

Three-dimensional printing produces a product by selectively spraying a liquid binder onto the applied powder. In other words, by using such a three-dimensional printing method, a ceramic shell for investment casting is directly made from ceramic powder, or a powder material based on starch component is used. You can also make. However, this three-dimensional printing method has a disadvantage in that shrinkage occurs due to thermal deformation because post-treatment is essential for increasing the density and strength of the product.

The selective laser sintering molding method applies a powder material made of a polymer, and manufactures a product by combining the powder by irradiating a laser beam. Since the polymer powders used in the selective laser sintering molding method are usually manufactured by a mechanical grinding method, there is a problem in that the precision is lowered such that the particle size is usually larger than 100 μm and the particle shape is irregular and the surface smoothness of the prototype is reduced. Therefore, it is difficult to apply when mass-produced products require complicated geometric shapes and strict precision. In addition, since the prototype is manufactured using only plastic powder, there is a problem that it is not suitable for manufacturing a prototype of a mass production product which requires strength.

The technical problem to be achieved by the present invention is to solve the above problems, the surface smoothness of the laser sintered prototype is good, not only suitable for precise prototype manufacturing, but also useful as a prototype of a mass production product requiring strength It is to provide a polymer powder for selective laser sintering molding that can be.

Another technical problem to be achieved by the present invention is to provide a manufacturing method capable of efficiently manufacturing the above-described polymer powder for selective laser sintering molding.

Another technical problem to be achieved by the present invention is to provide a selective laser sintering molding method for producing a precise and good prototype using the above-described selective laser sintering molding polymer powder.

In order to achieve the above technical problem, the polymer powder for selective laser sintering of the present invention used to rapidly form a prototype or mold of a three-dimensional shape directly from a three-dimensional CAD data using a rapid molding machine has a particle size. At least 1 type of microparticles | fine-particles selected from the group which consists of metal microparticles | fine-particles, ceramic microparticles | fine-particles, and glass fiber microparticles | fine-particles are mixed in this spherical polymer bead of 1-100 micrometers.

In addition, as another aspect of the present invention for achieving the above technical problem, the selective laser sintering molding of the present invention used to rapidly prototype a three-dimensional prototype or mold directly from a three-dimensional CAD data using a rapid molding machine In the polymer powder for laser sintering, a metal coating layer is formed on the surface of a spherical polymer bead having a particle diameter of 1 to 100 µm.

Since the above-described selective laser sintering polymer powders of the present invention are spherical beads of fine size, the surface smoothness of the laser sintering prototype is good using the same, so that the fine powder is not only suitable for precise production of prototypes, but also fine particles incorporated into the polymer powders are used in the prototypes. It can be usefully used as a prototype of mass-produced products that require strength by being uniformly dispersed to reinforce the strength of the prototype.

In order to achieve the above another technical problem, the polymer powder for selective laser sintering according to the present invention used to rapidly form a prototype or mold of a three-dimensional shape directly from a three-dimensional CAD data using a rapid molding machine. Method for the preparation of (S1) in a homogeneous solution of water and a dispersant, adding and stirring a mixture of one or more fine particles, monomers and initiators selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles; (S2) The mixture of (S1) is heated and suspension polymerization is carried out so that one or more fine particles selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles are mixed in spherical polymer beads having a particle diameter of 1 to 100 μm. Forming a polymer powder; And (S3) washing and drying the polymer powder.

In addition, as another aspect of the present invention for achieving the above technical problem, selective laser sintering molding according to the present invention used to rapidly mold a prototype or mold of a three-dimensional shape directly from the three-dimensional CAD data using a rapid molding machine Method for producing a polymer powder for (selective laser sintering) (S1) adding a mixture of monomer and initiator to a homogeneous solution of water and dispersant and stirring; (S2) heating the mixed solution of (S1) and performing suspension polymerization to form spherical polymer beads having a particle diameter of 1 to 100 µm; (S3) washing and drying the polymer beads; And (S4) performing electroless plating on the surface of the polymer beads to obtain a polymer powder having a metal coating layer formed thereon.

Hereinafter, the polymer powder for selective laser sintering according to the present invention, a manufacturing method thereof, and a selective laser sintering molding method using the same will be described in detail.

The polymer powder 10 for selective laser sintering of the present invention, which is used to rapidly form a three-dimensional prototype or mold directly from a three-dimensional CAD data using a rapid molding machine, has a particle diameter of 1 to 100 µm. The one or more kinds of fine particles 2 selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles are mixed in the spherical polymer beads 1 (see FIG. 1).

As mentioned in the prior art, the selective laser sintering molding method applies a powder material made of a polymer, and manufactures a product by combining the powder by irradiating a laser beam. However, conventional polymer powders used in the selective laser sintering molding method have a particle size of usually 100 μm or more, irregular particle shapes, and use only polymer-only powders, and thus require mass production of complex geometric shapes, strict precision and strength. Not suitable for manufacturing prototypes.

The present inventors solved this problem by producing a polymer powder for selective laser sintering molding in which at least one particle selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles is mixed in spherical polymer beads having a particle diameter of 1 to 100 μm. . That is, since the polymer powder for selective laser sintering molding according to the present invention is a spherical powder having a fine size, the laser sintering prototype using the same has good surface smoothness and is suitable for producing a precise prototype. In addition, since the fine particles mixed in the polymer powder is uniformly dispersed in the prototype to reinforce the strength of the prototype, it can be usefully used as a prototype of a mass production product that requires strength. In the case of laser sintering by simply mixing a polymer-only powder and metal particles that can reinforce the strength of the prototype, it is difficult to produce a prototype in which the particles are uniformly dispersed due to the difference in specific gravity of the polymer powder and the particulate. In the case of using the polymer powder in which the fine particles are mixed in the polymer beads as in the present invention, the fine particles are uniformly dispersed in the prototype, thereby achieving the purpose of strength reinforcement smoothly.

The particle size of the fine particles incorporated in the polymer beads is preferably 1 to 20 μm, and the content of the fine particles is 10 based on the total weight of the polymer beads in consideration of the effect of binding and strength reinforcement between the polymer powders during selective laser sintering. It is preferable that it is to 60 weight%. In particular, when the mass production product requires a predetermined electrical or thermal conductivity, it is preferable that metal fine particles are incorporated. The polymer beads may be exemplified by PVC, PS, PMMA, etc. as a polymer in which monomers are polymerized by suspension polymerization to form polymer beads.

The above-described selective polymer powder for laser sintering molding can be prepared by the following method.

First, a mixture of one or more fine particles, monomers and initiators selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles is added to a homogeneous solution of water and a dispersant and stirred (S1).

The dispersant may be polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, gelatin, tricalcium phosphate, polyacrylamide, polyethylene oxide, and the like, but is not limited thereto. Do not. The amount of the dispersant may be added, for example, 0.2 to 10 parts by weight based on 100 parts by weight of the monomer. As the monomer, polymer beads can be formed by suspension polymerization, for example, an aromatic vinyl monomer, acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms, and the like can be used. As an initiator, benzoyl peroxide, azobisisobutyronitrile, azobismethylbutyronitrile, azobiscyclohexacarbonitrile, and the like can be used, and the dosage is, for example, 0.01 to 5.0 parts by weight based on 100 parts by weight of the monomer. It can be put in. It is preferable that the particle diameter of the microparticles | fine-particles injected is 1-20 micrometers.

In step (S1), the monomer is incompatible with water, thus forming monomer droplets together with the fine particles in the water phase. However, while the fine particles are partially separated from the monomer droplets during stirring, the mixing rate of the fine particles may be lowered. If the fine particles are surface-treated with an emulsifying agent, for example, sodium dodecyl sulfate having an alkyl group having 10 or more carbon atoms, the surface is treated. The emulsifier improves the affinity of the microparticles for the monomers, thereby improving the mixing rate of the microparticles.

Subsequently, the mixture of (S1) is heated to, for example, 60 to 90 ° C. and subjected to suspension polymerization, so that the particle diameter of the polymer powder obtained is adjusted to 1 to 100 μm. The polymer powder obtained by suspension polymerization is spherical polymer beads, and fine particles introduced into the polymer beads are mixed. Methods for obtaining spherical polymer beads using suspension polymerization are well known, and for example, those disclosed in US Pat. Nos. 4,017,670, 4,085,165, 4,129,705 and the like can be referred to.

Then, washing and drying the polymer powder obtained by suspension polymerization to obtain the desired polymer powder for the selective laser sintering (S3).

On the other hand, the above-described effects of the polymer powder according to the present invention can be similarly achieved with the polymer powder 10 in which the metal coating layer 3 is formed on the spherical polymer bead surface 1 having a particle diameter of 1 to 100 μm (Fig. 2). That is, in the case of selective laser sintering using spherical polymer powder having a metal coating layer formed on the surface of the polymer bead, the metal coating layer formed on the surface of the polymer bead is destroyed by the laser, and the polymer powders bind to each other. It will be uniformly distributed. It is preferable that the thickness of the metal coating layer formed on the surface of the polymer bead is 1 to 50 µm, and the spherical polymer bead further comprises one or more fine particles selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles by the above-described method. Can be incorporated.

Such metal-coated polymer beads can be prepared by the following method.

First, a mixture of monomers and an initiator is added to a homogeneous solution of water and a dispersant and stirred (S1). Subsequently, the mixed liquid of (S1) is heated up and subjected to suspension polymerization to form spherical polymer beads having a particle diameter of 1 to 100 µm (S2). Then, (S3) the polymer beads are washed and dried. The above steps are applied in the same manner as the method for preparing the polymer powder, except that the fine particles are added.

Subsequently, electroless plating is performed on the obtained polymer bead surface to obtain a polymer powder having a metal coating layer (S4). Since the electroless plating method is well known to those skilled in the art, it is not described in detail herein. Of course, the polymer beads may be treated with a sensitizer solution or an activation solution before the electroless plating.

The polymer powder for selective laser sintering molding according to the present invention prepared as described above is a prototype or mold of a 3D shape by directly converting the polymer powder for selective laser sintering using a rapid molding machine from a known method, that is, 3D CAD data. It can be molded by.

Hereinafter, examples will be described in detail to help understand the present invention. However, embodiments according to the present invention can be modified in many different forms, the scope of the invention should not be construed as limited to the following examples. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

Example 1

3000 g of distilled water and 4.5 g of polyvinyl alcohol (n = 500) were put into a 5 L reactor and stirred. To the mixture was added 600 g of styrene monomer, 4 g of benzoyl peroxide and 120 g of acicular fine iron (Fe) fine particles having an average particle diameter of 10 µm. After the contents were sufficiently stirred, the temperature was raised to 80 ° C. and reacted for 7 hours while stirring at 300 rpm. Subsequently, the resultant was washed and dehydrated in a dehydrator and then dried at 80 ° C. for 24 hours to obtain a polymer powder for selective laser sintering molding having an average particle diameter of 63 μm.

Example 2

Electroless plating was performed using the polymer powder obtained in Example 1. In the pretreatment process, SnCl ₂ was used as a sensitive solution, and PdCl ₂ was used as an activation solution. The pretreated polymer beads were electroless plated using a copper sulfate solution, and the copper plated beads were washed and dried at 50 ° C. for 24 hours in a dryer to obtain a polymer powder for selective laser sintering molding having a thickness of 20 μm.

Example 3

The same procedure as in Example 2 was conducted except that no pure iron fine particles were added.

Example 4

A nickel powder solution was used instead of the copper sulfate solution in the same manner as in Example 2 to obtain a polymer powder for selective laser sintering molding having a nickel coating layer having a thickness of 20 μm.

Example 5

The same procedure as in Example 1 was carried out except that 300 g of methyl methacrylate was used instead of the styrene monomer. The average particle diameter of the obtained polymer powder was 54 µm. Next, a copper coating layer was formed in the same manner as in Example 2.

Example 6

The same procedure as in Example 2 was carried out except that the pure iron fine particles were previously treated with a sodium dodecylbenzene sulfate emulsifier.

3 is an optical micrograph of a polymer powder for selective laser sintering molding prepared according to Example 1. FIG. It can be seen that the metal fine particles are mixed in the spherical polymer beads.

First, since the polymer powder for selective laser sintering molding according to the present invention is a spherical powder having a fine size, the laser sintering prototype using the same has good surface smoothness and is suitable for producing a precise prototype. In addition, when the selective laser sintering molding using the polymer powder according to the present invention, the fine particles mixed in the polymer beads or the metal layer coated on the surface of the polymer beads is uniformly dispersed in the prototype to reinforce the strength of the prototype, thereby producing a mass produced. It can be usefully used as a prototype of the product.

Second, according to the method for producing a polymer powder for selective laser sintering molding according to the present invention, it is possible to easily produce a polymer powder having a spherical fine particle diameter, the fine particles are mixed or the metal is coated on the surface. In particular, when the fine particles are treated in advance with the emulsifier, the efficiency of incorporating the fine particles into the polymer beads can be improved.

Claims (9)

Polymer powder for selective laser sintering, which is used to rapidly form a three-dimensional prototype or mold directly from a three-dimensional CAD data by using a rapid molding machine, wherein the polymer powder has a particle diameter of 1 to 100 μm. A polymer powder for selective laser sintering, wherein spherical polymer beads are mixed with one or more fine particles selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles. The polymer powder for selective laser sintering according to claim 1, wherein the fine particles have an average particle diameter of 1 to 20 µm. Claim 3 was abandoned when the setup registration fee was paid. Claim 3 was abandoned when the setup registration fee was paid. Polymer powder for selective laser sintering, which is used to rapidly form a three-dimensional prototype or mold directly from a three-dimensional CAD data by using a rapid molding machine, wherein the polymer powder has a particle diameter of 1 to 100 μm. Polymer powder for selective laser sintering, characterized in that the metal coating layer is formed on the surface of the spherical polymer beads. Claim 4 was abandoned when the registration fee was paid. Claim 4 was abandoned when the registration fee was paid. The polymer powder for selective laser sintering according to claim 3, wherein the metal coating layer has a thickness of 1 to 50 µm. Claim 5 was abandoned upon payment of a set-up fee. Claim 5 was abandoned upon payment of a set-up fee. 4. The polymer powder for selective laser sintering according to claim 3, wherein the spherical polymer beads further contain one or more fine particles selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles. . A method for producing a polymer powder for selective laser sintering, which is used to rapidly prototype a three-dimensional shape prototype or mold directly from a three-dimensional CAD data using a rapid molding machine, (S1) adding and stirring a mixture of one or more fine particles, monomers and initiators selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles to a homogeneous solution of water and a dispersant; (S2) The mixture of (S1) is heated and suspension polymerization is carried out so that one or more fine particles selected from the group consisting of metal fine particles, ceramic fine particles and glass fiber fine particles are mixed in spherical polymer beads having a particle diameter of 1 to 100 μm. Forming a polymer powder; And (S3) A method for producing a polymer powder for selective laser sintering, characterized in that it comprises the step of washing and drying the polymer powder. The method of claim 6, wherein the fine particles of step (S1) are surface-treated with a sodium dodecyl sulfate emulsifier having an alkyl group having 10 or more carbon atoms. Claim 8 was abandoned when the registration fee was paid. Claim 8 was abandoned when the registration fee was paid. A method for producing a polymer powder for selective laser sintering, which is used to rapidly prototype a three-dimensional shape prototype or mold directly from a three-dimensional CAD data using a rapid molding machine, (S4) A method for producing a polymer powder for selective laser sintering comprising the step of performing electroless plating on the surface of the polymer bead to obtain a polymer powder having a metal coating layer formed thereon. Selective laser sintering molding, characterized in that the polymer powder for selective laser sintering of claim 1 or 2 is directly formed into a prototype or mold having a three-dimensional shape by using a rapid molding machine from the three-dimensional CAD data ( selective laser sintering).

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