JP2005319699A - Mold for producing wax model - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle which does not produce solidified wax in the vicinity of an injection opening. <P>SOLUTION: In a mold for producing a wax model which molds the wax model by injecting molten wax from the nozzle 4 into the molding cavity of the mold, a narrow part 43 is formed in a wax injection path 42 in the nozzle 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mold for manufacturing a wax model, and more particularly to a structure improvement of a nozzle portion for injecting molten wax into a mold.

FIG. 7 shows a schematic side view of a conventional wax model manufacturing mold. The mold includes an upper mold 5 fixed to a lift slider (not shown) via a frame 51 and a lower mold 6 fixed to the surface plate 3 via a frame 61. The lower mold 6 includes a columnar main body 62 and a truncated cone-shaped molding portion 63 projecting from the inner peripheral portion of the upper surface of the main body 62. As shown in the figure, the molding portion 63 is in a closed truncated conical shape, and a molding cavity 64 having a predetermined shape for molding a wax model (product) is formed therein. The upper die 5 has a cylindrical shape with the same diameter as the lower die 6, and a concave surface 52 that receives the molding portion 63 and adheres closely to the outer surface thereof is formed on the inner peripheral portion of the lower surface. A runner 53 is formed between the upper mold 5 and the lower mold 6 which are brought into close contact with each other, and one end thereof communicates with the molding cavity 64, and the other end of the runner 53 opens to the side. Here, the tip of the nozzle 7 is brought into pressure contact. The molten wax injected from the tip injection port of the nozzle 7 is supplied into the molding cavity 64 through the runner 53. After the molding is completed, when the upper mold 5 is raised and the slide lever 65 protruding from the outer peripheral surface of the main body 62 is operated in the circumferential direction, the mold wall of the molding part 63 is radially separated and opened by a known structure, and the product is released. It can be taken out. Note that Patent Document 1 discloses a mold including the above-described molding portion (core portion).
JP-A-8-112644

  However, in the conventional mold for manufacturing a wax model, since the runner 53 is relatively long, when the injection speed and the injection pressure are increased to prevent the molten wax from solidifying, the molding cavity 64 located below the runner 53 is provided. When molten wax flows down, air is entrapped and defects such as defective foam are likely to appear in the product. On the other hand, when the injection speed and the injection pressure are lowered, there is a problem that defects such as wrinkles, sink marks, or poor hot water are likely to appear on the product, and adjustment of the injection speed and the like is difficult. Therefore, it is conceivable to dispose the nozzle below the lower mold, provide a molding cavity on the lower mold side, supply molten wax from below, and also minimize the runner. Since it is hidden behind the lower mold and cannot be seen by the operator, the following problems occur. That is, in the conventional nozzle 7, as shown in FIG. 8, the solidified wax Wd may remain in the vicinity of the injection port 71 of the nozzle 7 receding from the runner opening, but the nozzle 7 is provided below the lower mold 6. The operator cannot confirm and remove the residual solidified wax Wd. For this reason, the solidified wax Wd is supplied into the molding cavity 64 at the time of the next injection, which causes surface wrinkles of the product. In addition, since the nozzle located below the lower mold cannot be visually recognized, there is a risk that it may be difficult to align the nozzle and the runner opening.

  Therefore, the present invention solves such problems, and a first object thereof is to provide a mold for manufacturing a wax model including a nozzle that does not generate a solidified wax in the vicinity of an injection port. A second object of the present invention is to provide a mold for manufacturing a wax model that can easily align a nozzle located below a lower mold and a runner opening.

  In order to achieve the above object, according to the first aspect of the present invention, molten wax is injected from a nozzle (4) into a molding cavity (14) of a mold having an upper mold (1) and a lower mold (2), and a wax model. In the mold for manufacturing a wax model, a narrow part (43) is formed in the middle of the wax injection path (42) in the nozzle (4).

  In the first aspect of the invention, since the narrow portion is formed in the middle of the wax injection path of the nozzle, when the injection is finished, the molten wax remains in the narrow portion in the middle of the wax injection path. Therefore, no solidified wax is generated near the injection port, and even when the operator cannot remove the solidified wax because the nozzle is located below the lower mold, the solidified wax is supplied into the molding cavity at the next injection. In other words, the generation of surface wrinkles on the product is prevented.

  In the second aspect of the invention, the nozzle (4) is positioned below the lower mold (2, 21), and a runner formed in the lower mold (2, 21) to supply molten wax into the mold ( 23, 24) is opened on the lower surface of the lower mold (2, 21), and the lower mold (2, 21) so that the opening (241) of the runner (23, 24) is located immediately above the nozzle (4). Guide means (25, 46) are provided for guiding and positioning. The guide means is formed on the guide wall (46) provided around the nozzle (4) and the lower surface of the frame (21) on which the lower mold (2) is mounted, and the guide wall (46) slides relative to each other. It can be constituted by a guide recess (25) which can be fitted.

  In the second aspect of the invention, the lower mold is guided and positioned by the guiding means so that the opening of the runner is directly above the nozzle even when the operator cannot visually recognize the molten wax. Injection supply is made surely.

  In addition, the code | symbol in the said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

  As described above, in the present invention, a nozzle that does not generate coagulated wax is provided in the vicinity of the injection port. Therefore, the nozzle is disposed below the lower mold, and molten wax is supplied to the molding cavity from below. In addition, it is possible to easily obtain a defect-free wax model by making the runner the shortest and without difficulty in adjusting the injection speed and the like. Further, it is possible to easily and reliably align the nozzle located below the lower mold and the runner opening.

  FIG. 1 shows a schematic side view of a mold for producing a wax model of the present invention. The mold includes an upper mold 1 fixed to a lift slider (not shown) via a frame body 11 and a lower mold 2 fixed to a surface plate 3 via a frame body 21. The upper mold 1 includes a columnar main body 12 and a truncated cone-shaped molding portion 13 that protrudes from the inner periphery of the lower surface of the main body 12. The molding part 13 has a truncated cone shape, and a molding cavity 14 having a predetermined shape for molding a wax model (product) is formed therein. The lower die 2 has a cylindrical shape with the same diameter as the upper die 1, and a concave surface 22 is formed on the inner periphery of the upper die so as to receive the molding portion 13 and adhere to the outer surface thereof. A runner 23 is formed in the center of the lower die 2 in the vertical direction, and the upper end of the runner 23 communicates with the molding cavity 14, and the lower end of the runner 23 is a frame 21 on which the lower die 2 is mounted. It communicates with a runner 24 penetratingly formed in the center in the vertical direction.

  An injection head 41 provided with a nozzle 4 is embedded in the surface plate 3 below the frame body 21, and the nozzle 4 is located immediately below the opening 241 of the runner 24, as shown in FIG. The nozzle tip is in pressure contact with the runner opening 241. A cross section of the nozzle 4 is shown in FIG. The nozzle 4 is a cylindrical body having a flange portion 44 at the base end, and the tip (upper end) surface thereof is a bulging arc surface. At the center of the nozzle 4, a wax injection path 42 is formed so as to penetrate the nozzle 4 in the vertical direction. The inner diameter of the wax injection path 42 gradually decreases from the vertical direction toward the intermediate position, and a narrowed portion 43 having the smallest inner diameter is formed in the middle of the injection path 42.

  A ring-shaped heater 45 (FIGS. 3 and 4) is embedded around the nozzle 4 of the ejection head 41 (FIG. 1), and a ring-shaped guide wall 46 is formed at a constant height on the outer periphery thereof. On the other hand, a guide recess 25 is formed in the lower surface of the runner 24 around the opening 241 of the runner 24. As shown in FIG. 5, the guide recess 25 has a semicircular stopper portion 251 having the same diameter as the outer diameter of the guide wall 46 with the runner opening 241 as the center, and extends laterally from the outer periphery of the stopper portion 251 with the same width. And a guide portion 252 that opens to the outer edge of the frame body 21.

  When a wax model is molded with a wax model manufacturing mold having such a structure, the opening of the guide portion 252 of the guide recess 25 of the frame 21 on which the lower mold 2 is mounted matches the guide wall 46. In this state, the frame body 21 is slid on the surface plate 3 until the guide wall 46 fitted in the guide recess 25 relatively reaches the stopper portion 251 along the guide portion 252. . Thereby, even when the operator cannot visually recognize the nozzle 4, the opening 241 of the runner 24 of the frame body 21 is accurately positioned directly above the nozzle 4. When the upper die 1 is lowered and brought into close contact with the lower die 2 and the nozzle 4 is raised in this state, the tip thereof comes into pressure contact with the opening 241 (state shown in FIG. 1). When molten wax is injected from the injection port 421 (FIG. 2) of the nozzle 4, the molten wax is supplied into the molding cavity 14 through the runners 24 and 23.

  In this embodiment, the length of the runners 24 and 23 from the nozzle 4 to the molding cavity 14 can be made shorter than before. Therefore, even if the injection speed and injection pressure of the molten wax are lowered, the molten wax is easily filled into the molding cavity 14 because the runners 24 and 23 are short, and the holding pressure can be maintained until the runners 24 and 23 are solidified. Therefore, the product does not have defects such as wrinkles, sink marks, and poor hot water. Moreover, since it is what is called push-up injection | pouring, it is also avoided that a bubble defect arises in a product.

  As described above, since the narrow portion 43 is formed in the wax injection path 42 of the nozzle 4 after the injection is finished, the molten wax is in the middle of the wax injection path 42 as shown in FIG. It stays in the narrow part 43. Thereby, coagulated wax does not occur near the upper injection port 421. And in the narrow part 43, it is heated with the heater 45 (FIG. 1) around the nozzle 4, and molten wax does not solidify. Therefore, even when the operator cannot remove the coagulated wax because the nozzle 4 is located below the lower mold 2, the coagulated wax is not supplied into the molding cavity 14 at the next injection. Wrinkle generation is prevented. Of course, the use position of the nozzle of this embodiment is not limited to the lower part of the lower mold. Further, the shape of the narrow portion is not limited to that of the present embodiment.

  When taking out the product, the upper die 1 is raised and separated from the lower die 2, and the bar-shaped gripping margin portion W1 (FIG. 6) protruding downward from the molding portion 13 of the upper die 1 is grasped by the take-out arm AM. . In this state, when the slide lever 15 (FIG. 1) protruding from the outer peripheral surface of the main body portion 12 is operated in the circumferential direction, the mold wall of the molding portion 13 is radially separated and opened by a known structure, and the product can be taken out. it can. At this time, since the molding part 13 opens downward, even if the wax piece is peeled off from the product, it is quickly dropped and discharged from the molding part 13 and does not remain in the molding part 13. Thereby, when the mold wall of the molding part 13 is closed, problems such as the wax piece being caught and the mold surface being damaged can be avoided.

It is a schematic side view of the metal mold | die for wax model manufacture which shows one Embodiment of this invention. It is sectional drawing of a nozzle. It is a top view of a nozzle installation part. It is a perspective view of a nozzle installation part. It is a principal part enlarged plan view of a frame. It is a side view of the shaping | molding part of an upper mold | type. It is a schematic side view of the conventional mold for wax model manufacture. It is sectional drawing of a nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Upper mold | type, 14 ... Molding cavity, 2 ... Lower mold | type, 21 ... Frame, 23, 24 ... Runway, 241 ... Opening, 25 ... Guide recess, 4 ... Nozzle, 42 ... Wax injection path, 43 ... Narrow 46, guide wall.

Claims (3)

A wax model manufacturing mold in which molten wax is injected from a nozzle into a molding cavity of a mold to mold a wax model, wherein a narrow part is formed in the middle of the wax injection path in the nozzle. Production mold. The mold includes an upper mold and a lower mold, the nozzle is positioned below the lower mold, and a runner formed in the lower mold to supply the molten wax into the mold is a lower mold. The mold for wax model manufacture according to claim 1, further comprising guide means for guiding and positioning the lower mold so that the lower mold is opened and the runner opening is located immediately above the nozzle. The guide means is constituted by a guide wall provided around the nozzle and a guide recess formed on the lower surface of the frame on which the lower mold is placed, and the guide wall is fitted so as to be relatively slidable. The mold for wax model manufacture according to claim 2.

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