Hollow sprue

Abstract

To provide a hollow sprue which can enhance the adhesion rigidity of a waxed technical material and the sprue during a process of manufacturing a metal technical material, and can suppress a use amount of a metal being a raw material of the metal technical material.SOLUTION: A use method of a hollow sprue includes a step for bonding an adhesion member which is fused to an end part E1 of the hollow sprue, and a step for making a tip part T formed at a cut face S of the end part E1 penetrate the waxed technical material. Preferably, the method further includes a step for implanting a plurality of the hollow sprues 1 into a board-shaped base B, and lengths of the hollow sprues 1 at this time become long as approximating to a center of the base B.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a hollow sprue used in the casting process of a fabricated metal product. [Background technology]

[0002] Conventionally, the manufacturing process of metal processed products (typically dental prostheses, jewelry, etc., hereinafter referred to as metal prostheses) produced by casting has typically been as follows.

[0003] (Step A1) A dental technician (typically a dental technician or jewelry manufacturing technician) forms a dental prosthesis (hereinafter referred to as a wax prosthesis) using wax as the material. In the case of a dental prosthesis, it is common to first make a mold of the patient's oral cavity to create a plaster model (called an intraoral model), and then form the wax prosthesis on the intraoral model.

[0004] (Step A2) The wax prosthesis is placed on the wax base via a sprue. A sprue is a solid rod-shaped jig made of plastic or other material that can be completely incinerated. As shown in Figure 1, the end face E of a conventional sprue is cut off so that the angle α relative to the center line X of the sprue is approximately 90°. The technician applies a small amount of melted wax (wax that acts as an adhesive) to one end face of the sprue to bond it to the prosthesis (so-called surface bonding), and then embeds the other end face of the sprue into the base. At this time, an appropriate amount of melted wax is piled up in a mound shape around the connection points between the sprue and the prosthesis, and around the connection points between the sprue and the base, to increase the adhesive strength (build-up).

[0005] (Step A3) The wax base, sprue, and wax dental prosthesis are embedded in plaster. After the plaster hardens, it is heated to dissolve or vaporize the wax base, sprue, and wax dental prosthesis inside the plaster. This creates a continuous cavity inside the plaster that is modeled after the shapes of the base, sprue, and wax dental prosthesis.

[0006] (Step A4) Molten metal is poured into the cavity formed in the plaster where the base was left. The cavity where the sprue was left becomes a flow channel, and the molten metal flows into the cavity where the wax prosthesis was left.

[0007] (Step A5) After the metal hardens, the plaster is peeled off to obtain a metal product in which the metal dental prosthesis, sprue, and base are integrated. The sprue is cut from the metal dental prosthesis, and finally the metal dental prosthesis is polished to complete the final product, the metal dental prosthesis. When separating the metal dental prosthesis and the sprue, the cutting is done so that some of the buildup and sprue end remain on the metal dental prosthesis side. Then, the buildup remaining on the surface of the metal dental prosthesis is removed by polishing. This prevents the metal dental prosthesis from being damaged during cutting. Summary of the Invention [Problem to be solved by the invention]

[0008] As explained in step A5, in the manufacturing process of metal dental prostheses, it is necessary to remove the buildup and sprue ends remaining on the metal dental prosthesis by grinding. However, the prices of precious metals used as raw materials for metal dental prostheses have risen in recent years, and the cost of raw materials lost in this grinding process has now become non-negligible.

[0009] The present invention has been made to solve these problems, and aims to provide a hollow sprue that increases the adhesive strength between a wax dental prosthesis and a sprue during the manufacturing process of the metal dental prosthesis, and that can reduce the amount of metal used as a raw material for the metal dental prosthesis. [Means for solving the problem]

[0010] According to one embodiment, the hollow sprue is a sprue used in casting metal prostheses, and is characterized in that it has a tubular body, and at least one end E1 of the body has a cutting surface S formed thereon that is inclined with respect to the axis X of the tube. According to one embodiment, the hollow sprue is characterized in that a molten adhesive material is applied to a tip T formed on the cut surface S of one end E1 of the body, and the tip T is penetrated into the wax dental prosthesis, causing the molten adhesive material to flow into the internal cavity of the body. According to one embodiment, a method for using a hollow sprue is characterized by having a tubular body, at least one end E1 of the body having a cut surface S inclined with respect to the axis X of the tube, and includes the steps of applying a molten adhesive material to the end E1 of the hollow sprue and penetrating a tip T formed on the cut surface S of the end E1 into a wax dental prosthesis. According to one embodiment, the method of using the hollow sprue further includes a step of planting multiple hollow sprues in a plate-shaped base, and in the planting step, the length of the hollow sprue is longer the closer it is to the center of the base. According to one embodiment, the base is a plate-shaped base on which a plurality of hollow sprues are planted, and the longer the hollow sprues are planted, the closer they are to the center of the base. According to one embodiment, the base has a multi-layer structure including a first layer and a second layer made of wax that is softer than the first layer. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a hollow sprue that can increase the adhesive strength between a wax dental prosthesis and a sprue during the manufacturing process of a metal dental prosthesis, and can reduce the amount of metal used as a raw material for the metal dental prosthesis. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the structure of a conventional sprue. [Figure 2] FIG. 2 is a perspective view of a hollow sprue 1. [Figure 3] FIG. 2 is a front view of the hollow sprue 1. [Figure 4] FIG. 2 is a rear view of the hollow sprue 1. [Figure 5] FIG. 2 is a plan view of the hollow sprue 1. [Figure 6] FIG. 2 is a bottom view of the hollow sprue 1. [Figure 7] FIG. 2 is a left side view of the hollow sprue 1. [Figure 8] FIG. 2 is a right side view of the hollow sprue 1. [Figure 9] FIG. 2 is a cross-sectional view of a hollow sprue 1. [Figure 10] FIG. 2 is a diagram showing how a dental prosthesis is connected to a hollow sprue 1. [Figure 11] FIG. 2 is a cross-sectional view showing how a dental prosthesis and a hollow sprue 1 are connected. [Figure 12] 1 is a diagram showing an example of a wax dental prosthesis W into which a hollow sprue 1 has penetrated. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. 10 is a diagram showing the embedding process. [Figure 16] FIG. 2 is a diagram showing an example of a casting CA produced in a casting process. [Figure 17] FIG. [Figure 18] FIG. 10 is a diagram showing an example of a metal technical work D produced in a cutting step. [Figure 19] 10 is a flowchart showing an example of a method for using the hollow sprue 1. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. <Structure> The structure of the hollow sprue 1 according to the embodiment of the present invention will be described with reference to FIGS.

[0014] FIG. 2 is a perspective view of the hollow sprue 1, FIG. 3 is a front view of the hollow sprue 1, FIG. 4 is a rear view of the hollow sprue 1, FIG. 5 is a plan view of the hollow sprue 1, FIG. 6 is a bottom view of the hollow sprue 1, FIG. 7 is a left side view of the hollow sprue 1, FIG. 8 is a right side view of the hollow sprue 1, and FIG. 9 is a cross-sectional view of the hollow sprue 1.

[0015] The hollow sprue 1 is a tubular structure. That is, it is a columnar object formed by extruding a donut-shaped cross-section C along an orthogonal axis X. The values of the length L, outer diameter R1, and inner diameter R2 (<R1) of the hollow sprue 1 are not limited, but for example, in the production of dental prosthetics, it is convenient to use when 7 mm < L < 30 mm, 1 mm < R1 < 3 mm, and 0.1 mm < wall thickness (= R1 - R2) < 0.3 mm.

[0016] The material of the hollow sprue 1 is typically a plastic that can be completely burned, that is, a plastic that completely melts or vaporizes in the heating process. Note that it is not limited to such plastics, and any other material that is solid at room temperature, easy to process, and has the property of melting or vaporizing when heated can also be used. However, the melting point of the material needs to be lower than the melting point of the mold material such as gypsum described later and higher than the melting wax used as an adhesive for the wax prosthesis.

[0017] Both ends E1, E2 of the hollow sprue 1 are cut off so that at least one of them forms a cut surface S inclined with respect to the axis X. For example, in the example of FIG. 9, the end E1 is cut obliquely to form a cut surface S having a sharp tip T.

[0018] <Manufacturing Method> A typical manufacturing method of the hollow sprue 1 will be described. (Manufacturing Method 1) A hollow plastic rod having a length LL (>L) is cut every length L. The cut surface is not made orthogonal to the axis X of the hollow plastic rod, but an inclination angle is provided. Thereby, the hollow sprue 1 having cut surfaces S formed at both ends E1, E2 can be manufactured.

[0019] (Manufacturing Method 2) A hollow plastic rod of length LL (>L) is cut into lengths of 2L. The cut surfaces may be perpendicular to the axis X of the hollow plastic rod. Next, the hollow plastic rod cut into lengths of 2L is cut at the position of length L. The cut surfaces are not perpendicular to the axis X of the hollow plastic rod, but are inclined. This allows the manufacture of a hollow sprue 1 in which a cut surface S is formed at one end E1 and a conventional perpendicular cut surface is formed at the other end E2.

[0020] <How to use> A typical method of using the hollow sprue 1 will be described with reference to the flowchart of FIG.

[0021] (Step B1) A dental technician (typically a dental technician or jewelry manufacturing technician) molds a wax dental prosthesis using wax. In the case of dental prostheses, it is common to first make a mold of the patient's oral cavity to create a plaster model (called an intraoral model), and then mold the wax dental prosthesis onto the intraoral model.

[0022] (Step B2) A wax dental prosthesis is placed on a wax base via a hollow sprue 1. First, the wax dental prosthesis and the hollow sprue 1 are bonded together, and then the hollow sprue 1 is implanted into the wax base (implantation process).

[0023] 10 and 11 are diagrams showing how to connect a wax dental prosthesis and the hollow sprue 1. The technician inserts the tip T of the cut surface S formed at the end E1 of the hollow sprue 1 into the wax dental prosthesis W. At this time, as shown in FIG. 11, it is preferable to insert the cut surface S so that only a part of it, not the entire cut surface S, is embedded in the wax dental prosthesis W. This makes the area of ​​the surface where the wax dental prosthesis W and the hollow sprue 1 intersect smaller than the area of ​​the cross section C.

[0024] When the hollow sprue 1 is inserted into the wax dental prosthesis W, a small amount of preheated molten wax M is applied to the tip T of the hollow sprue 1 before the insertion. At this time, as shown in FIG. 11, the molten wax M flows into the cavity inside the hollow sprue 1. At the same time, a small amount also adheres to the outer periphery of the hollow sprue 1, forming a buildup. The molten wax M gradually cools and hardens, bonding the wax dental prosthesis W and the hollow sprue 1 together.

[0025] In conventional sprues, the sprue is supported primarily by a buildup of molten wax M adhering to the outer periphery of the sprue. In contrast, in the hollow sprue 1, the molten wax M also supports the hollow sprue 1 in the inner cavity, allowing for a stronger bond between the hollow sprue 1 and the wax prosthesis W. Furthermore, in the hollow sprue 1, the contact area between the molten wax M and the hollow sprue 1 is greater than in conventional sprues, resulting in a stronger adhesive force. In particular, in this embodiment, the cut surface S is inclined with respect to the direction of travel of the hollow sprue 1 (the direction of the axis X), allowing more molten wax M to flow into the interior than when the cut surface S is perpendicular to the axis X. This makes it easy to obtain a strong adhesive force.

[0026] As described above, in this embodiment, the area of ​​the surface where the wax prosthesis W and the hollow sprue 1 intersect is smaller than that of a conventional sprue (the area of ​​cross section C). Therefore, the size of the buildup formed around it can also be smaller than in the past. Furthermore, because the molten wax M penetrates into the hollow sprue 1 and exerts adhesive force, the size of the buildup can be further reduced.

[0027] FIG. 12 shows an example of a wax dental prosthesis W into which a hollow sprue 1 has been inserted. In this example, several types of hollow sprues 1 with different lengths L are used. Preferably, the color of the hollow sprues 1 may be changed depending on the length L. For example, if there are three types of hollow sprues 1 with lengths L1, L2, and L3, the hollow sprue 1 with length L1 is colored red, the hollow sprue 1 with length L2 is colored yellow, and the hollow sprue 1 with length L3 is colored green. This makes it easy to distinguish between hollow sprues with different lengths L.

[0028] FIG. 13 shows a process for implanting multiple hollow sprues 1 into a wax base B. The wax base B has a plate-like shape, and in this example, it is disk-shaped. Preferably, the disk-shaped base B has a multi-layer structure including a first layer made of a relatively hard wax and a second layer made of a softer wax than the first layer. The hollow sprues 1 are implanted into the surface of the second layer. This allows the first layer to ensure the rigidity of the base B, while the flexibility of the second layer makes it easy to implant the hollow sprues 1, thereby efficiently progressing the implantation process. Note that preheating the second layer before starting the process softens the surface of the second layer, further improving workability.

[0029] In the implantation process, the longest hollow sprue 1 is first implanted near the center of the disk. Subsequently, other hollow sprues 1 are implanted. At this time, as shown in the cross-sectional view of FIG. 14, it is preferable to implant hollow sprues 1 with longer lengths L closer to the center of the disk and hollow sprues 1 with shorter lengths L further away from the center. For example, consider a case where the hollow sprues 1 are colored differently depending on their length L, with the hollow sprue 1 with length L1 being red, the hollow sprue 1 with length L2 being yellow, and the hollow sprue 1 with length L3 being green (L1 > L2 > L3). In this case, the red hollow sprue 1 is first implanted in the center of the base B, then the yellow hollow sprues 1 are implanted around the red hollow sprue 1, and finally the green hollow sprues 1 are implanted around the yellow hollow sprue 1. This facilitates the subsequent cutting process (the process of separating the metal prosthesis from the sprue).

[0030] (Step B3) The wax base, hollow sprue 1, and wax dental prosthesis are embedded in plaster (embedding process). Figure 15 shows the embedding process. First, the wax base with the hollow sprue 1 embedded therein is placed in a stainless steel casting ring CR. Next, liquid plaster is poured into the casting ring to embed it. After the plaster hardens, it is heated to dissolve or vaporize the wax and plastic inside, thereby forming a series of cavities inside the plaster that are molded to the shape of the base, hollow sprue 1, and wax dental prosthesis.

[0031] (Step B4) Molten metal is poured into the cavity formed in the plaster that corresponds to the site of the base (casting process). The cavity that corresponds to the site of the hollow sprue 1 becomes a flow path, and the molten metal flows into the cavity that corresponds to the site of the wax prosthesis.

[0032] (Step B5) After the metal has hardened, the plaster is peeled off to obtain a metal product (casting CA) that combines the metal prosthesis, sprue, and base (Figure 16). The technician uses a circular saw SW or similar tool to separate the metal prosthesis D from the casting CA (cutting process), and finally polishes the metal prosthesis (polishing process), completing the final metal prosthesis.

[0033] As shown in FIG. 17 , the work should begin with the metal prosthesis D implanted on the outer periphery of the base, and proceed to the metal prosthesis D implanted closer to the center of the base. In the implantation process of this embodiment, a hollow sprue 1 is used that is shorter toward the outer periphery of the base and longer toward the center. Therefore, even if the sprue (more precisely, the portion of the casting CA corresponding to the hollow sprue 1 trace) is left on the base after the metal prosthesis D implanted on the outer periphery is cut off, this does not interfere with the cutting of the metal prosthesis D implanted closer to the center with the circular saw SW. If all the hollow sprues 1 were the same length, the sprues on the outer periphery would get in the way when cutting the metal prosthesis D on the inner periphery with the circular saw SW. Therefore, the sprues on the outer periphery from which the metal prosthesis D was cut are first removed from the base, and then the cutting process for the metal prosthesis D on the inner periphery is performed. Alternatively, the cutting process of the central metal dental prosthesis D must be performed while tilting the circular saw SW so as to avoid the sprue on the outer periphery from which the metal dental prosthesis D has been cut. In the former case, the number of steps increases, resulting in a decrease in work efficiency. In the latter case, the cutting process of the central metal dental prosthesis D is limited in terms of work accuracy, which makes it easy for excess metal to remain on the metal dental prosthesis D. This excess metal is lost in the polishing process, resulting in a waste of expensive metal material. However, according to this embodiment, as shown in FIG. 18 , the metal dental prosthesis D can be cut out while leaving the sprue on the base. In other words, since there is no need to remove the sprue from the base, work efficiency is significantly improved. Furthermore, the circular saw SW can easily access the metal dental prosthesis D embedded in the center of the base and cut it with high precision, thereby reducing waste of metal material.

[0034] When separating the metal dental prosthesis from the sprue, the cutting is performed so that some of the buildup and the end of the sprue remain on the metal dental prosthesis. The buildup remaining on the surface of the metal dental prosthesis is then removed by polishing. This prevents the metal dental prosthesis from being damaged during cutting.

[0035] In this embodiment, a cut surface S inclined with respect to the axis X of the hollow sprue 1 is formed on at least one end E1 of the hollow sprue 1 body. This allows the area of ​​the surface where the wax dental prosthesis and the hollow sprue 1 intersect and the amount of build-up to be reduced compared to conventional methods. This results in less build-up and debris from the hollow sprue 1 remaining on the surface of the metal dental prosthesis than conventional methods. Therefore, the amount of metal lost in the polishing process is reduced compared to conventional methods, making it possible to reduce the manufacturing costs of metal dental prostheses.

[0036] In this embodiment, when multiple hollow sprues 1 are planted in a disk-shaped wax base, the closer to the center of the base, the longer the hollow sprues 1. This eliminates the need to remove the sprues from the base in the cutting process, thereby improving work efficiency.

[0037] Note that if a dome-shaped base is used instead of a disk-shaped base, the same effect can be achieved even when multiple hollow sprues 1 of the same length are installed. However, the work of installing the hollow sprues 1 vertically is much easier with a disk-shaped base. Furthermore, if all the hollow sprues 1 are installed approximately vertically, the metal prosthesis can be cut one after another while maintaining a substantially constant circular saw angle during the cutting process, which improves workability. On the other hand, when installing the hollow sprues 1 on a dome-shaped base, the hollow sprues 1 are likely to tilt. If the installation angles of the hollow sprues 1 are inconsistent, the circular saw must be applied at different angles to each sprue during the cutting process, which can reduce workability and result in waste of metal material. [Explanation of symbols]

[0038] 1 hollow sprue E,E1,E2 End X-axis L: Distance between cutting surfaces of sprue R1 Sprue outer diameter R2 Sprue inner diameter S Cut surface of sprue end α is the angle between the cutting plane S and the axis X T Tip of cut surface S W wax dentures M Melted Wax B. Base

Claims

1. A sprue used in casting metal crafts, It has a tubular body, At least one end E1 of the body has a cut surface S inclined in one direction with respect to the axis X of the tubular body, An opening is formed on the cut surface S that is inclined with respect to the axis X. Hollow sprue.

2. A method for using a hollow sprue having a tubular body, wherein at least one end E1 of the body has a cut surface S inclined in one direction with respect to an axis X of the tubular body, and an opening is formed on the cut surface S inclined with respect to the axis X, applying a molten adhesive material to the end E1 of the hollow sprue; and a step of penetrating a tip portion T formed on the cutting surface S of the end portion E1 into a wax dental prosthesis. How to use hollow sprue.

3. The step of penetrating causes the molten adhesive material to flow into an internal cavity of the body. A method for using the hollow sprue according to claim 2.

4. In the step of penetrating, only a part of the cut surface S is embedded in the wax prosthesis. A method for using the hollow sprue according to claim 2.

5. The method further includes a step of planting a plurality of the hollow sprues on a plate-shaped base, In the step of planting, the length of the hollow sprue is longer as it approaches the center of the base. A method for using the hollow sprue according to claim 2.

6. A plate-shaped base on which a plurality of hollow sprues according to claim 1 are planted, The hollow sprue is planted so that it is longer as it approaches the center of the base. Foundation.

7. The base has a multi-layer structure including a first layer made of wax and a second layer made of wax that is softer than the first layer. The base of claim 6.

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