JP4483791B2 - Method for producing green ring molded body - Google Patents

Description

  The present invention relates to a method for producing a green ring molded body.

  For example, a sintered ring made of a noble metal such as silver is formed by forming a green ring molded body in which a noble metal clay is molded and a noble metal powder is hardened with a binder, and is then fired to fit on a finger. It is widely used as a decorative item.

As an apparatus and method for forming such an unfired ring molded body, for example, as shown in Patent Documents 1 to 3 below, a noble metal clay formed into a strip shape is wound around a core material or the like, A method of joining end portions (hereinafter referred to as “first conventional example”), a method of punching and forming a noble metal clay formed into a strip shape (hereinafter referred to as “second conventional example”), or a cylinder There is known a method (hereinafter referred to as “third conventional example”) in which a precious metal clay formed into a shape is cut by a predetermined length.
JP 2002-177025 A Japanese Patent Laid-Open No. 11-78396 Japanese Patent No. 3067402

  However, in the first conventional example, among the conventional methods for producing an unfired ring molded body, the ends of the band-shaped molded body are joined to each other. In the sintered ring, there is a possibility that cracks are likely to occur in the joint, and in the second conventional example, since the strip-shaped formed body is punched, the yield is deteriorated, and further, the third conventional example is used. In the example, since the cylindrical shaped body is cut at a predetermined length, there is a problem that distortion occurs at the time of cutting, and it is difficult to form a green ring shaped body with a stable shape. there were.

  The present invention has been made in consideration of such circumstances, and manufacture of a green ring molded body that can form a green ring molded body with high accuracy without deteriorating the yield or reducing the strength. It aims to provide a method.

  In order to solve the above problems and achieve such an object, the method for producing an unfired ring molded body of the present invention forms a ring molded body in which noble metal clay is molded and noble metal powder is hardened with a binder. A method for manufacturing an unfired ring molded body, in which a first plate-like body and a second plate-like body are connected to respective one end portions via a connecting portion, and each overlapping surface of these plate-like bodies is A storage space is formed between the two overlapping surfaces in a closed state in which these overlapping surfaces are overlapped, and at least the first plate-like body opens to the storage space, and the storage space A package in which a through hole having a smaller diameter than the inner diameter is formed, and a package in which a housing recess is formed on the overlapping surface of the second plate-like body, and the closed state is used. From the through hole to the storage space. After placing the genus clay, the both sides of one end in the longitudinal direction of the plate-like pressing body having a rectangular shape in plan view are inserted into the storage space while being in sliding contact with the inner peripheral surface of the through hole. The one end portion of the noble metal clay is rotated by the rotation of the plate-like pressing body by rotating a body around a rotation axis extending in parallel with the longitudinal direction and passing through the center portion in the width direction of the plate-like pressing body. After pressing the portion facing the circular locus surface formed by the end surface on the side with one end portion of the plate-like pressing body, pushing away toward the inner peripheral surface side of the storage space to form an unfired ring molded body, One end of a plate-like pressing body is extracted from the storage space and the through hole, and then a lid is attached to the package to close the through hole, thereby forming the green ring molded body enclosed in the package. And

In this invention, after placing noble metal clay in the storage space, one end of the plate-shaped pressing body is inserted into the storage space, and the plate-shaped pressing body is rotated around the rotation axis while moving forward toward the inside of the storage space. By doing so, the portion of the noble metal clay facing the circular locus surface formed by the end surface on the one end side by the rotation of the plate-like pressing body is pressed by one end portion of the plate-like pressing body, while the inner circumference of the storage space is It becomes possible to push away toward the surface side. Therefore, the portion of the noble metal clay arranged in the storage space is the inner diameter portion through which the portion facing the circular trajectory surface penetrates, while the portion pushed away toward the inner peripheral surface side of the storage space is on the inner peripheral surface side. By pressing the outer diameter portion, an unfired ring molded body that has been molded is formed.
As a result, an integral green ring molded body having no joints is obtained, and a high-precision green ring molded body having high density and no surface defects is formed with uniform strength throughout the entire area. can do. Further, since the green ring molded body is formed by molding without cutting or cutting, such a green ring molded body can be formed with improved yield and production efficiency.
Further, the molding as described above is performed in the storage space of the package, and after molding, the plate-like pressing body is extracted from the storage space and the through hole, and then the lid is attached to the package to close the through hole. Since an encapsulated green ring molded body is obtained, there is no need to separately provide a series of steps such as taking out the green ring molded body from a mold or the like after molding and enclosing the molded body in a package. Therefore, production efficiency can be further improved.
Furthermore, since there is no need to provide a separate process for encapsulating in the package, it is possible to prevent variations in the components and physical properties between the formation of the green ring molded body and the encapsulation in the package. Thus, a high-quality green ring molded body can be formed.

  Here, the plate-like pressing body is provided so as to be able to rotate counterclockwise or clockwise around the rotation axis, and the rotation center axis of the one end portion is a reference in a plan view of the surface of the plate-like pressing body. In the left part or the right part, an inclined dent that gradually decreases in depth from the side surface of the plate-like pressing body connected to this part toward the rotation axis may be formed.

  In this case, when the plate-like pressing body is rotated around the rotation axis while pressing the noble metal clay arranged in the storage space with one end of the plate-like pressing body, The opposing portion can be guided toward the inner peripheral surface side of the storage space by the inclined recess formed at one end of the plate-like pressing body. Therefore, it becomes possible to form a mold without causing a gap between the clay and the inner peripheral surface of the storage space by bringing the precious metal clay into close contact over the entire inner peripheral surface of the storage space during molding. It is possible to reliably form an unfired ring molded body having high accuracy and high density and having no surface defects. Further, when the green ring molded body is molded, the inclined concave portion allows a portion of the noble metal clay facing the circular locus surface to be accommodated in the storage space without applying a large rotational driving force to the plate-like pressing body. It becomes possible to favorably push away toward the inner peripheral surface, and an obstruction factor for automating this molding can be reduced.

  Further, the package in the closed state is sandwiched by a pair of mold surfaces provided so as to be able to approach and separate from each other from the back side opposite to the overlapping surface in the first and second plate-like bodies, and the mold In the state where the through hole and the outside are communicated with each other through the introduction hole formed at a position facing the opening of the through hole in the surface, the storage space is provided with the introduction hole and the through hole. Precious metal clay was placed, and then one end of the plate-like pressing body was inserted into the storage space while sliding both sides of the inner peripheral surface of the introduction hole and the through hole, and sealed in a package. The green ring molded body may be formed.

  In this case, since the green ring molded body is formed in a state where the package is sandwiched between a pair of molds, it is possible to stabilize the arrangement position of the package with respect to the plate-shaped pressing body at the time of molding, and the above effects Will surely be effective.

Further, the storage recess is formed to bulge to the back side opposite to the overlapping surface in the second plate-like body, and the pair of mold surfaces make the package into the first and second plate-like shapes. When sandwiched from the back surface side opposite to the body overlapping surface, the bulged portion of the back surface of the second plate-shaped body may be housed in a recess formed in the mold surface.
In this case, at the time of molding, the contact area between the mold surface and the back surface of the second plate-like body can be increased, and the arrangement position of the package can be further stabilized with respect to the plate-like pressing body.

  Furthermore, the storage recess is formed on each overlapping surface of the first and second plate-like bodies, and the storage space is formed by the storage recesses facing each other in the closed state. May be.

  In this case, when the package is opened and the storage space is halved, an unfired ring molded body is disposed in one of the storage recesses of the first and second plate-shaped bodies, and the storage recess At least a part of the green ring molded body protrudes from the formed overlapping surface. Therefore, it becomes possible to easily take out the non-fired ring molded body from the storage recess by pulling the protruding portion. In particular, for example, the inner peripheral surface of the storage space has a concave curved surface shape that is concave outward in the radial direction, and the green ring molded body has a curved surface shape whose outer peripheral surface is convex outward in the radial direction. Even an unfired ring molded body for a so-called Koumaru ring can be easily removed from the package.

  According to the method for manufacturing a green ring molded body according to the present invention, the green ring molded body can be formed with high accuracy without deteriorating the yield or decreasing the strength.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1 to FIG. 5, the unfired ring molded body manufacturing apparatus 10 of the present embodiment is provided so as to be able to approach and separate from each other, and sandwiches a package P, which will be described later, with mold surfaces 11 a and 14 a facing each other. A pair of molds 11 and 14 and a plate-like pressing body having a rectangular shape in plan view and having one end portion in the longitudinal direction (hereinafter referred to as “tip portion”) 13a inserted into the storage space 12 of the package P 13, the green ring molded body W3 is molded in the storage space 12 of the package P in which the precious metal clay W is disposed, with the package P sandwiched between the mold surfaces 11a and 14a. .

The pair of molds 11 and 14 includes a fixed mold 11 and a movable mold 14, and the mold surfaces 11 a and 14 a of these molds 11 and 14 are respectively provided in the central portions in the direction along the surfaces 11 a and 14 a. Recesses 11b and 14b are formed. In addition, a plurality of positioning pins 11 c that are convex toward the movable mold 14 are provided upright on the outer peripheral edge in the direction along the surface 11 a on the mold surface 11 a of the fixed mold 11. On the other hand, the mold surface 14a of the movable mold 14 has holes 14c larger in diameter than the pins 11c at positions facing the positioning pins 11c, and the positioning pins 11c are inserted into the holes 14c when the mold is clamped. It has come to be. Furthermore, the movable mold 14 is provided with an introduction hole 14d that opens from the back surface opposite to the mold surface 14a to the recess 14b.
The concave portions 11b and 14b and the introduction hole 14d formed in the fixed die 11 and the movable die 14 are all circular in a plan view, and each circular central axis is a rotation center axis of a plate-like pressing body 13 described later. It almost coincides with O.

  The plate-like pressing body 13 is a plate-like body having a rectangular shape in plan view, extends in parallel with the longitudinal direction of the plate-like pressing body 13, and can rotate around the rotation axis O passing through the center in the width direction of the plate-like pressing body 13. It is supported by. The plate-like pressing body 13 has a front end surface 13f facing the introduction hole 14d and the other end connected to a driving unit (not shown), and can be rotated around the rotation axis O by the driving unit. The mold surfaces 11a and 14a at the time of mold clamping can be advanced and retracted. Further, the size, that is, the width in the direction perpendicular to the longitudinal direction in the direction along the front surface 13b and the back surface 13c of the plate-like pressing body 13 of the distal end portion 13a is made equal to the inner diameter of the introduction hole 14d.

  Here, in the present embodiment, the plate-like pressing body 13 is provided so as to be capable of rotating counterclockwise or clockwise around the rotation axis O, and in plan view of the front and back surfaces 13b and 13c of the plate-like pressing body 13, respectively. An inclination in which the depth gradually decreases toward the rotation axis O from the side surface 13e of the plate-like pressing body 13 continuous to the left portion or the right portion of the tip portion 13a with respect to the rotation center axis O. A recess 15 is formed.

  In the present embodiment, the plate-like pressing body 13 can be rotated clockwise around the rotation axis O, and the front-and-back surfaces 13b and 13c of the plate-like pressing body 13 in the plan view of the front end portion 13a. An inclined recess 15 is formed in the right portion 13d with the rotation center axis O as a reference. Further, the inclined recess 15 is open to both the front end surface 13f of the plate-like pressing body 13 and the side surface 13e. Further, the depth of the inclined recess 15 is equal throughout the longitudinal direction.

  The size of the inclined recess 15 in the direction in which the rotation axis O extends is greater than or equal to the height of the storage space 12 of the package P described later, that is, greater than or equal to the size of the green ring molded body W3 to be molded. ing. In addition, the inclined recess 15 has the rotation axis O located from the end on the side surface 13e side of the plate-like pressing body 13 in the width direction of the plate-like pressing body 13 in the right portion 13d of the front surface 13b and the back surface 13c. It is formed to reach the part. Further, the depth at the end on the side surface 13e side as the deepest portion of the inclined recess 15 is the distance between the front surface 13b and the rear surface 13c of the plate-like pressing body 13, that is, about half the thickness of the plate-like pressing body 13. It is said that the size. Furthermore, the rear end portion 15a in the longitudinal direction of the inclined recess portion 15 is an inclined surface whose depth gradually increases toward the front end side.

  Here, in the package P, the first plate-like body 21 and the second plate-like body 22 are connected to their respective one ends via hinges (connection portions) 23, and these first and second plate-like bodies are provided. The overlapping surfaces 21b, 22b of the 21, 22 can be opened and closed, and the storage space 12 is formed between the overlapping surfaces 21b, 22b in a closed state where these overlapping surfaces 21b, 22b are overlapped, and at least the first The plate-like body 21 is formed with a through hole 21c that opens into the storage space 12 and has a smaller diameter than the inner diameter of the storage space 12, while the overlapping surface 22b of the second plate-like body 22 has A storage recess 22c that forms the storage space 12 is formed. The package P is integrally formed of a resin material such as polyethylene terephthalate (PET).

  In the present embodiment, the first and second plate-like bodies 21 and 22 are rotatable about the hinge 23 so that the overlapping surfaces 21b and 22b approach and separate from each other in the thickness direction. Further, the through-hole 21c is formed not only in the first plate-like body 21 but also in the second plate-like body 22, and further, the storage recess 22c is formed not only in the second plate-like body 22 but also in the first plate-like body. The storage space 12 is formed by the storage recesses 22c and 22c facing each other in the closed state.

  Here, in this embodiment, the inner peripheral surfaces of the storage recesses 22c and 22c are the overlapping surfaces from the back surfaces 21d and 22d side opposite to the overlapping surfaces 21b and 22b in the first and second plate-like bodies 21 and 22, respectively. The diameter gradually increases in the shape of a concave curved surface toward 21b and 22b. That is, the inner peripheral surfaces of the storage recesses 22c and 22c are concave curved surfaces having the largest inner diameters at the portions located on the overlapping surfaces 21b and 22b. Thereby, the inner peripheral surface of the storage space 12 formed with the storage recesses 22c and 22c facing each other in the closed state is formed into a concave curved surface having a maximum inner diameter in the portion located on the overlapping surfaces 21b and 22b. Yes.

  The storage space 12 and the through holes 21c and 21c are circular in plan view, and in the closed state, the respective central axes of the circular shapes are coaxially positioned. Thereby, the storage space 12 is communicated with the outside through the through holes 21c and 21c. The inner diameters of the through holes 21c and 21c are equal to the inner diameter of the introduction hole 14d of the movable mold 14. Furthermore, the storage recesses 22c and 22c bulge toward the back surfaces 21d and 22d of the first and second plate-like bodies 21 and 22, and the thicknesses of the first and second plate-like bodies 21 and 22 are as follows. It is substantially equivalent throughout the entire back surface.

In the package P, a plurality of holes P1 penetrating in the thickness direction are formed in the outer position of the storage space 12 in the closed state.
Of the above constituent elements, at least the part in contact with the noble metal clay W, that is, the outer surface of the distal end portion 13a of the plate-like pressing body 13, the bottom surface of the concave portion 11b of the fixed mold 11 and the package P are released from each other with a small friction coefficient. It is coated or formed with a material with excellent properties. Examples of such a material include ultra-high molecular weight polyethylene having a friction coefficient of about 0.09 or silicon.

  That is, the fixed mold 11, the plate-like pressing body 13, and the package P may be integrally formed of a material having a small coefficient of friction and excellent releasability, such as ultra high molecular weight polyethylene. The pressing member 13 and the package P are integrally formed of another material, and at least the surface with which the noble metal clay W contacts is coated with a material having a small coefficient of friction and excellent releasability, such as silicon. Good.

Next, a method for forming an unfired ring molded body using the unfired ring molded body manufacturing apparatus 10 configured as described above will be described.
First, as shown in FIG. 1, the package P closed by overlapping the overlapping surfaces 21 b and 22 b of the first and second plate bodies 21 and 22 on the back surface 22 d of the second plate body 22 is stored. The bulging portion corresponding to 22c is disposed in the recess 11b of the fixed mold surface 11a, and is placed on the mold surface 11a with the positioning pin 11c inserted into the hole P1.

  Next, as shown in FIG. 2, the movable mold 14 is moved forward toward the fixed mold 11 and clamped, whereby the package P is attached to the back surfaces 21 d of the first and second plate-like bodies 21, 22. 22d side is sandwiched by the mold surfaces 11a and 14a, and the bulging portion corresponding to the storage recess 22c on the back surface 21d of the first plate-like body 21 is disposed in the recess 14b of the movable mold surface 14a, and the positioning pin 11c Is inserted into the hole 14c of the movable mold surface 14a.

  As described above, the introduction hole 14 d of the movable mold 14, the storage space 12 of the package P and the through holes 21 c and 21 c are coaxially arranged on the rotation axis O, and the introduction hole 14 d and the first plate-like body 21 are arranged. The storage space 12 communicates with the outside through the through hole 21c.

  And after arrange | positioning the noble metal clay W in the storage space 12 from the introduction hole 14d via the through-hole 21c of the 1st plate-shaped body 21, the plate-shaped press body 13 moves forward toward the storage space 12, and this board The distal end portion 13a of the shaped pressing body 13 is inserted into the storage space 12 with its both side surfaces 13e, 13e being in sliding contact with the respective inner peripheral surfaces of the introduction hole 14d and the through hole 21c of the first plate-like body 21. Thus, by rotating the plate-like pressing body 13 around the rotation axis O while inserting the tip end portion 13a of the plate-like pressing body 13 into the storage space 12, the plate-like pressing by the rotation of the noble metal clay W is performed. The portion facing the circular locus surface formed by the tip surface 13f of the body 13 is pushed away toward the inner peripheral surface of the storage space 12 while being pressed by the tip portion 13a (FIG. 3).

  At this time, the precious metal clay W scraped toward the other end side of the plate-like pressing body 13 by the front end surface 13 f of the plate-like pressing body 13 is inclined by the inclined recess 15 of the plate-like pressing body 13. It flows toward the side surface 13e connected to the recess 15, that is, toward the inner peripheral surface of the storage space 12. Therefore, in the process in which the plate-like pressing body 13 is moved forward, the portion of the noble metal clay W that faces the circular locus surface is displaced toward the inner peripheral surface side of the storage space 12 to be the inner diameter portion W1 that penetrates. On the other hand, the portion pushed away toward the storage space 12 is pressed against the inner peripheral surface side of the storage space 12 to form an outer diameter portion W2. As described above, the noble metal powder is hardened with a binder, the noble metal clay W is molded into a ring shape that is integrally continuous in the circumferential direction, and the outer peripheral surface is a curved shape that protrudes radially outward. A green ring molded body W3 for a so-called Koumaru ring is formed.

  In the process of forming the green ring molded body W3, both side surfaces 13e and 13e of the plate-like pressing body 13 are kept in sliding contact with the inner peripheral surfaces of the through hole 21c and the introduction hole 14d of the first plate-like body 21. . Further, when the front end surface 13f of the plate-like pressing body 13 passes through the through hole 21c of the second plate-like body 22 and comes into contact with the bottom surface of the concave portion 11b of the fixed mold 11, the noble metal clay W is almost eliminated on this bottom surface. The forward movement and rotation of the plate-like pressing body 13 are stopped.

  Then, as shown in FIG. 4, the plate-like pressing body 13 is moved backward with respect to the storage space 12, and the movable mold 14 is moved backward with respect to the fixed mold 11 to open the mold. The package P in which the green ring molded body W3 is arranged is moved to the movable mold 14 side, removed from the positioning pin 11c, and the green ring molded body W3 is removed from the molds 11 and 14 together with the package P.

  Thereafter, a lid (not shown) is attached to the package P, the through holes 21c and 21c are closed, and an unfired ring molded body W3 enclosed in the package P is formed. Here, as the lid, for example, a pin having a flange formed on one end thereof is adopted, and this is continuously fitted into the through holes 21c, 21c and the inner diameter portion W1 of the green ring molded body W3. Alternatively, a simple pin may be fitted in this way. Further, an adhesive tape may be detachably attached to the openings of the through holes 21c and 21c in the back surfaces 21d and 22d of the first and second plate-like bodies 21 and 22.

  In order to open the package P, the lid is removed from the package P, and then the first and second plate-like bodies 21 and 22 are separated from each other in the thickness direction of the overlapping surfaces 21b and 22b. As shown in FIG. 6, the storage space 12 is halved in the height direction by rotating the hinge 23 as the center. Of the storage recesses 22c of the first and second plate-like bodies 21 and 22, from the storage recess 22c where the unfired ring molded body W3 is arranged, the storage recesses of the unfired ring molded body W3. A portion protruding with respect to the overlapping surfaces 21b and 22b on which 22c is formed is pulled, and the green ring molded body W3 is taken out.

  The green ring molded body W3 taken out from the package P in this way is, for example, manually drawn on the outer peripheral surface thereof and then shaved with a knife, a drill, a router, or the like along the design picture. A carving is placed and then fired. And a sintered ring is formed by performing grinding | polishing etc. on the outer surface of this ring molded object W3 after baking.

Here, as the noble metal clay W, for example, silver clay containing silver powder, an organic binder, and fats and oils can be employed.
As the silver powder, for example, an Ag fine powder having an average particle diameter of 2 μm or less: 15 to 50% by mass, and the balance is composed of a mixed powder composed of Ag powder having an average particle diameter of more than 2 μm and 100 μm or less. Silver powder or an Ag fine powder having an average particle diameter of 0.5 to 1.5 μm: 15 to 50% by mass, and the balance is composed of a mixed powder made of Ag powder having an average particle diameter of 3 to 20 μm. A second silver powder can be employed. And as silver clay, 1st silver powder or 2nd silver powder: 95-99 mass%, organic type binder: 0.8-4.8 mass%, fats and oils: 0.1-0.5 mass % May be employed.

  Here, the Ag fine powder having an average particle diameter of 2 μm or less is more preferably a spherical Ag fine powder produced by a chemical reduction method or the like. The reason why the content of the Ag fine powder is limited to 15 to 50% by mass is that the average particle size: the mechanical strength of the sintered ring obtained when the content of the Ag fine powder of 2 μm or less is less than 15% by mass. On the other hand, if the content of the fine Ag powder having an average particle size of 2 μm or less exceeds 50% by mass, the amount of the organic binder for making the clay is increased, and the shrinkage ratio during firing is increased. This is because it is not preferable because of the increase. A more preferable range of the content of the Ag fine powder having an average particle diameter of 2 μm or less is 20 to 45% by mass. Furthermore, the remaining Ag powder contained in the first and second silver powders was made into an Ag powder having an average particle size of more than 2 μm and not more than 100 μm. The mechanical strength of the resulting sintered ring is weakened at 2 μm or less. If the diameter exceeds 100 μm, for example, when engraving or the like is performed on the outer peripheral surface of the green ring molded body W3, not only this processed part but also a wide part including the peripheral part may be scraped off. This is due to the reason that the formability as clay becomes worse, such as it becomes difficult to engrave and the like.

  The amount of the first and second silver powders contained in the silver clay is limited to 95 to 99% by mass. If the amount is less than 95% by mass, the shrinkage rate during firing is increased, which is not preferable. If the content exceeds 50%, the shape retaining property of the unsintered ring molded body W3 is deteriorated, and it is likely to be deformed when the unsintered ring molded body W3 is placed in the distribution process, or the handleability thereof is deteriorated. Because there is no.

  The organic binder contained in the silver clay may be any binder such as cellulose binder, polyvinyl binder, acrylic binder, wax binder, resin binder, starch, gelatin, flour, etc. In particular, water-soluble cellulose is most preferable. These binders are added in order to quickly gel when heated to facilitate the shape retention of the unfired ring molded body W3. However, the amount added is less than 0.8% by mass, while it is not effective. When the content exceeds 5% by mass, fine cracks are generated in the green ring molded body W3, and the gloss of the sintered ring is also decreased, which is not preferable. Therefore, the binder contained in the silver clay is set to 0.8 to 4.8% by mass.

  Furthermore, the addition amount of fats and oils contained in silver clay is preferably 0.1 to 0.5% by mass. Fats and oils to be added are organic acids (oleic acid, stearic acid, phthalic acid, palmitic acid, sepacic acid, acetylcitric acid, hydroxybenzoic acid, lauric acid, myristic acid, caproic acid, enanthic acid, butyric acid, capric acid), organic acid Esters (organic acid esters having methyl, ethyl, propyl, butyl, octyl, hexyl, dimethyl, diethyl, isopropyl, and isobutyl groups), higher alcohols (octanol, nonanol, decanol), polyvalent Examples include alcohol (glycerin, arabit, sorbitan), ether (dioctyl ether, didecyl ether) and the like.

  In addition, when the silver clay mentioned above is employ | adopted as the noble metal clay W, the unbaking ring molded object W3 is heated at about 600 to 900 degreeC for 5 to 30 minutes, for example with an electric kettle, a burner, a microwave oven, a gas stove, etc. Can be fired. In addition, if the unsintered ring molded body W3 is not fired, even if it fails when engraved on its outer peripheral surface, the precious metal clay W is embedded in the part or wetted with water so that it becomes familiar. After repairing the site to a smooth surface, it can be carved again.

  As described above, according to the method for manufacturing an unfired ring molded body according to the present embodiment, after the noble metal clay W is arranged in the storage space 12, the tip portion 13a of the plate-like pressing body 13 is inserted into the storage space 12, By rotating the plate-like pressing body 13 around the rotation axis O while moving the plate-like pressing body 13 toward the inside of the storage space 12, a circular shape formed by the tip surface 13f by the rotation of the plate-like pressing body 13 in the noble metal clay W is formed. The portion facing the locus surface can be pushed away toward the inner peripheral surface side of the storage space 12 while being pressed by the tip portion 13 a of the plate-like pressing body 13. Accordingly, the portion of the noble metal clay W arranged in the storage space 12 is the inner diameter portion W1 through which the portion facing the circular locus surface passes, while the portion pushed away toward the inner peripheral surface side of the storage space 12 An unfired ring molded body W3 molded by being pressed to the outer peripheral surface side to be the outer diameter portion W2 is formed.

  From the above, an integral green ring molded body W3 having no joint portion is obtained, and has a uniform strength over the entire region, and has a high density and a high precision green ring molded body W3 free from surface defects. Can be formed. Further, since the green ring molded body W3 is formed by die molding without cutting or cutting, such a green ring molded body W3 can be formed with improved yield and production efficiency.

  Further, the molding as described above is performed in the storage space 12 of the package P. After the molding, the plate-like pressing body 13 is extracted from the storage space 12 and the through hole 21c, and then the lid is attached to the package P and the through hole 21c. Since the green ring molded body W3 encapsulated in the package P is obtained by closing the ring, for example, the green ring molded body is taken out from the mold after molding and the molded body is sealed in the package. Since it is not necessary to provide a series of steps separately, production efficiency can be further improved.

  Furthermore, since there is no need to separately provide a process for encapsulating in the package P as described above, it is possible to prevent the components and physical properties from being dispersed after the green ring molded body W3 is formed and encapsulated in the package P. Therefore, a high-quality green ring molded body W3 can be formed.

  Further, in the present embodiment, since the inclined depression 15 is formed in the plate-like pressing body 13, while pressing the noble metal clay W arranged in the storage space 12 with the tip portion 13a of the plate-like pressing body 13, When the plate-like pressing body 13 is rotated about the rotation axis O, a portion of the noble metal clay W that faces the circular locus surface is guided toward the inner peripheral surface of the storage space 12 by the inclined recess 15. It becomes possible. Accordingly, the precious metal clay W is brought into close contact over the entire inner peripheral surface of the storage space 12 at the time of molding, and is molded without causing a gap between the clay W and the inner peripheral surface of the storage space 12. Therefore, it is possible to reliably form an unfired ring molded body W3 having high accuracy and high density and having no surface defects.

  Further, when the green ring molded body W3 is molded, even if a large rotational driving force is not applied to the plate-like pressing body 13, a portion of the noble metal clay W facing the circular locus surface is inclined by the inclined recess 15. It becomes possible to favorably push away toward the inner peripheral surface of the storage space 12, and the obstruction factor for automating this molding can be reduced.

  Furthermore, in the present embodiment, since the rear end portion 15a of the inclined recess 15 is the inclined surface, when the noble metal clay W is pressed by the plate-like pressing body 13, the rear of the inclined recess 15 is obtained. As the noble metal clay W bites into the end portion 15a, it is possible to avoid the necessity of applying a large rotational driving force to the plate-like pressing body 13, and the noble metal clay W adheres to the rear end portion 15a. Can be prevented from becoming difficult. Therefore, the obstruction factor which automates the above shaping | molding can further be reduced.

  Furthermore, in the present embodiment, since the green ring molded body W3 is molded with the package P sandwiched between the fixed mold 11 and the movable mold 14, the arrangement position of the package P with respect to the plate-shaped pressing body 13 is molded. It becomes possible to stabilize, and the above-mentioned effect is surely achieved.

  Further, at the time of molding, the bulging portion corresponding to the storage recess 22 c on the back surface 22 d of the second plate 22 is disposed in the recess 11 b of the fixed mold surface 11 a and stored on the back surface 21 d of the first plate 21. Since the bulging portion corresponding to the recess 22c is disposed in the recess 14b of the movable mold surface 14a, the mold surfaces 11a and 14a and the back surfaces 21d and 22d of the first and second plate-like bodies 21 and 22 are formed at the time of molding. It is possible to increase the contact area with the plate-shaped pressing body 13 and to further stabilize the arrangement position of the package P.

  Further, the package P has the storage recess 22c formed on the overlapping surfaces 21b and 22b of the first and second plate-like bodies 21 and 22, respectively, and when these overlapping surfaces 21b and 22b are overlapped, Since the storage recesses 22c face each other, the storage space 12 is formed. Therefore, when the package P is opened and the storage space 12 is halved, the first and second plate-like bodies 21, Among the 22 storage recesses 22c, 22c, an unfired ring molded body W3 is disposed in one of the storage recesses 22c, and the unfired ring molded body W3 is formed from the overlapping surfaces 21b, 22b where the storage recesses 22c are formed. Some will protrude. Therefore, it becomes possible to easily take out the green ring molded body W3 from the storage recess 22c by pulling the protruding portion. Thereby, even if the unsintered ring molded body W3 is for the above-described rounded ring ring shown in the present embodiment, the ring molded body W3 can be easily taken out from the storage recess 22c.

  Furthermore, in the present embodiment, through holes 21c and 21c that are coaxially positioned in the closed state are formed in both of the storage recesses 22c and 22c of the first and second plate-like bodies 21 and 22, Since the front end surface 13f of the plate-like pressing body 13 is in contact with the bottom surface of the recess 11b formed in the fixed mold 11 at the final stage of molding, in order to prevent the package P from being damaged, It becomes possible to prevent the molding conditions such as the material of the package P and the plate-like pressing body 13 and the forward driving force and the rotational driving force of the plate-like pressing body 13 from being restricted, and an obstructive factor for automating the above molding. Can be further reduced.

  And the unsintered ring molded body W3 formed as described above has a uniform strength over the entire area, is highly accurate, and further, when formed with the above-mentioned silver clay, Without causing fine cracks in the fired ring molded body W3, it is possible to provide good shape retention and formability and to reduce the shrinkage rate during firing. Furthermore, a sintered ring obtained by firing such an unfired ring molded body W3 can have good mechanical strength and gloss.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the said embodiment, although the inclination recessed part 15 was formed in the plate-shaped press body 13, this inclination recessed part 15 does not necessarily need to form. That is, you may employ | adopt the plate-shaped press body 13 by which the front-end | tip parts 13a of the front and back surfaces 13b and 13c were made into the flat surface.
Furthermore, in the said embodiment, although the apparatus 10 and method which form the non-fired ring molded object W3 for what is called a round ring were demonstrated, the outer peripheral surface shape of this molded object is not specifically limited, For example, an outer peripheral surface May be formed as a green ring molded body for a so-called flat ring that extends in parallel with the rotation axis O.

  Moreover, in the said embodiment, the said bulging part in the back surfaces 21d and 22d of the 1st, 2nd plate-shaped bodies 21 and 22 is arrange | positioned in the recessed parts 11b and 14b, and the package P is spread over the whole back surfaces 21d and 22d. The green ring molded body W3 is formed in a state of being sandwiched between the fixed mold surface 11a and the movable mold surface 14a. For example, the outer peripheral edges of the back surfaces 21d and 22d of the first and second plate-like bodies 21 and 22 are formed. The green ring molded body W3 may be formed in a state where only the portion is sandwiched or the side surface of the package P is supported.

Furthermore, in the embodiment, the storage recess 22 c is formed not only on the second plate 22 but also on the first plate 21, but may be formed only on the second plate 22. In this case, the first and second plate-like bodies 21 and 22 have connecting portions that are slidable in a direction along the surfaces 21b and 22b around an axis perpendicular to the overlapping surfaces 21b and 22b. It may be connected via.
In addition, the storage recess 22c is bulged toward the back surfaces 21d and 22d of the first and second plate-like bodies 21 and 22, but instead of being recessed with respect to the overlapping surfaces 21b and 22b, the back surface 21d. , 22d may adopt a package P having a flat surface.

Furthermore, the fixed mold 11 and the movable mold 14 are not limited to a metal mold, and may be a plastic mold formed of a resin material, for example.
Furthermore, in the embodiment, the through hole 21c is formed not only in the first plate body 21 but also in the second plate body 22, but in the package P, it faces the tip surface 13a of the plate-like pressing body 13. You may make it form only in the 1st plate-shaped body 21. FIG.

  An unfired ring molded body can be formed with high accuracy without deteriorating the yield or reducing the strength.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram when the apparatus which implements the manufacturing method of the non-baking ring molded object shown as one Embodiment which concerns on this invention in the longitudinal cross-sectional view, Comprising: The 1st process drawing of this manufacturing method is shown. The 2nd process drawing of the manufacturing method using the manufacturing apparatus of the unbaking ring fabrication object shown in Drawing 1 is shown. The 3rd process drawing of the manufacturing method using the manufacturing apparatus of the unbaking ring fabrication object shown in Drawing 1 is shown. The 4th process drawing of the manufacturing method using the manufacturing apparatus of the non-baking ring molded object shown in FIG. 1 is shown. It is a top view of the front end surface of the plate-shaped press body of the manufacturing apparatus of the unbaking ring molded object shown in FIGS. 5A is a plan view and FIG. 5B is a cross-sectional side view showing a state in which a package installed in the unfired ring molded body manufacturing apparatus shown in FIGS. 1 to 4 is opened.

Explanation of symbols

11 Fixed type (a pair of types)
11a Fixed mold surface (mold surface)
12 storage space 13 plate-like pressing body 13a tip portion (one end portion) of plate-like pressing body
13b Surface of the plate-shaped pressing body 13c Back surface of the plate-shaped pressing body 13e Side surface of the plate-shaped pressing body 13f Front end surface (one end surface) of the plate-shaped pressing body
14 Movable type (a pair of molds)
14a Movable mold surface (mold surface)
14d Introduction hole 15 Inclined recess 21 First plate-like body 21b, 22b Overlapping surface 21c Through hole 21d Back surface of first plate-like body 22 Second plate-like body 22c Storage recess 22d Back surface of second plate-like body 23 Hinge ( Connecting part)
O Rotation axis P Package W Precious metal clay W3 Unfired ring molded body

Claims (5)

A method for producing an unfired ring molded body in which a noble metal clay is molded to form a ring molded body in which a noble metal powder is hardened with a binder,
The first plate-like body and the second plate-like body are connected to the respective one end portions via a connecting portion so that the respective overlapping surfaces of these plate-like bodies can be opened and closed, and these overlapping surfaces are overlapped. A storage space is formed between the two overlapping surfaces in the combined closed state, and at least the first plate-like body is formed with a through hole that opens to the storage space and has a diameter smaller than the inner diameter of the storage space. On the other hand, on the overlapping surface of the second plate-like body, a package in which a storage recess that forms the storage space is formed,
After placing noble metal clay in the storage space from the through hole of the package in the closed state,
While inserting both side surfaces of one end portion in the longitudinal direction of the plate-shaped pressing body having a rectangular shape in plan view into the storage space while being in sliding contact with the inner peripheral surface of the through-hole, the plate-shaped pressing body is connected to the longitudinal direction. A circular trajectory formed by the end surface on the one end side by the rotation of the plate-like pressing body of the noble metal clay by rotating around the rotation axis passing through the center in the width direction of the plate-like pressing body. After pressing the part facing the surface with one end of the plate-like pressing body, pushing away toward the inner peripheral surface side of the storage space to form an unfired ring molded body,
One end of the plate-like pressing body is extracted from the storage space and the through hole, and then a lid is attached to the package to close the through hole, thereby forming the green ring molded body enclosed in the package. A method for producing an unfired ring molded product. In the manufacturing method of the unbaking ring molded object of Claim 1,
The plate-like pressing body is provided so as to be able to rotate counterclockwise or clockwise around the rotation axis, and the left side of the one end portion with respect to the rotation center axis in the plan view of the surface of the plate-like pressing body. An unsintered ring molded body characterized in that an inclined dent that gradually decreases in depth from the side surface of the plate-like pressing body connected to this portion to the rotation axis is formed in the portion or the right portion. Production method. In the manufacturing method of the unbaking ring molded object according to claim 1 or 2,
The package in the closed state is sandwiched by a pair of mold surfaces provided so as to be able to approach and separate from each other from the back side opposite to the overlapping surface of the first and second plate-like bodies, and A noble metal clay in the storage space through the introduction hole and the through hole in a state where the through hole and the outside communicate with each other through the introduction hole formed at a position facing the opening of the through hole. After that, one end portion of the plate-like pressing body is inserted into the storage space while sliding both side surfaces of the inner circumferential surface of the introduction hole and the through hole, and the unsealed package sealed A method for producing an unfired ring molded body, comprising forming a fired ring molded body. In the manufacturing method of the unbaking ring molded object according to claim 3,
The storage recess is formed to bulge to the back surface side opposite to the overlapping surface in the second plate-like body, and the package of the first and second plate-like bodies is formed by the pair of mold surfaces. An unsintered ring molding characterized in that, when sandwiched from the back surface side opposite to the overlapping surface, the bulged portion of the back surface of the second plate-like body is housed in a recess formed in the mold surface. Body manufacturing method. In the manufacturing method of the non-baking ring molded object in any one of Claim 1 to 4,
The storage recess is formed on each overlapping surface of the first and second plate-like bodies, and a package is used in which the storage space is formed by the storage recesses facing each other in the closed state. The manufacturing method of the unbaking ring molded object made into.

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