JP2017013091A - Wax mold and lost wax casting method - Google Patents

Abstract

Kind Code: A1 A wax molding die that can reduce the production time and production cost of a mold, is suitable for production of a small quantity and a variety of products, can easily respond to a design change, is lightweight, and can be easily moved and handled. A wax mold 100 includes a lower mold 11 and an upper mold 12 made of resin for defining a cavity 20, a gate pipe 30 penetrating through the resin upper mold 12 to the cavity 20, and a gate pipe 30. At a position where the shrinkage cavities are likely to occur at a position spaced apart from each other. And a deaeration tube 50 penetrating the upper mold. [Selection] Figure 2

Description

  The present invention relates to a resin wax mold and a lost wax casting method using the resin wax mold.

  The lost wax casting method is a casting method that utilizes the fact that wax (WAX) melts at a relatively low temperature. That is, in the lost wax casting method, molten wax is poured into a mold to create a wax model, the wax model is coated with a heat-resistant material, and then heated to dewax and melt into the mold cavity. This is a casting technique for casting a metal to produce a casting.

  In the conventional lost wax casting method, the wax model mold includes, for example, a thin wax core made of a flexible material and an insert member that fits into a concave portion inside the wax core, and an undercut portion is formed of the wax core. A mold suitable for forming a wax model is disclosed in which a wax core can be easily separated from a wax model by pulling out an insert member after the wax model is solidified (see, for example, Patent Document 1).

JP 2000-233259 A

  By the way, in the conventional lost wax casting method, a wax model is molded using a mold as a wax mold. Molds take about 30 to 45 days to produce molds, and the production cost exceeds about 1 million yen. Moreover, when the original mold is changed in design, it is necessary to remodel the wax mold. However, since the production time and production cost of the mold increase, it is difficult to quickly respond to the design change. Furthermore, since the mold is heavy, it is difficult to move and handle.

  Therefore, in view of the above circumstances, the object of the present invention is to reduce the production time and production cost of the mold, suitable for the production of a small variety of products, easy to respond quickly to design changes, lightweight and movable. An object of the present invention is to provide a wax mold that is easy to handle and a lost wax casting method using the wax mold.

  In order to achieve the above object, a wax mold according to the present invention includes a resin lower mold and an upper mold for defining a cavity, and a gate pipe that penetrates the resin upper mold to reach the cavity. Provided at a location where shrinkage cavities are likely to occur at a position separated from the gate pipe, and provided at a hot water pipe that penetrates the upper mold made of the resin and reaches the cavity, and a portion where the gas accumulation in the cavity is likely to occur. And a deaeration pipe penetrating through the upper mold made of the resin.

  In the configuration of the wax mold, it is preferable that the gate pipe, the feeder pipe, and the deaeration pipe are formed of a metal tube.

  Moreover, it is preferable that a resin placing piece mold for molding an undercut portion is disposed between the lower mold and the upper mold.

  Furthermore, it is preferable that a concavo-convex shape portion for positioning the mold is formed on the mold-matching surface where the molds contact each other.

  And it is preferable that the reinforcement material for preventing the bending of a resin material is arrange | positioned in parts other than the said cavity of the said lower mold | type and the said upper mold | type.

  The lost wax casting method according to the present invention includes a step of producing a prototype, a step of producing a wax mold according to the prototype, and a step of producing a wax model by injecting molten wax into the wax mold. A plurality of wax models attached to a sprue runner to produce a tree, a coating treatment process to produce a mold by immersing the wax tree in a binder and attaching refractory sand, and a wax tree in the mold A dewaxing treatment step that melts and removes, a step of firing the mold, a casting step of pouring molten metal into the cavity of the mold, a mold releasing step of breaking the mold and taking out the casting, and A finish processing step for adjusting individual products by machining a casting, and the wax molding die is the resin wax molding according to any one of the above Characterized in that it is formed by.

  According to the present invention, it is possible to reduce the production time and production cost of a mold, suitable for production of a small variety of products, easily responding to design changes, lightweight, easy to move and handle, and The excellent effect of realizing a lost wax casting method using the wax mold is exhibited.

It is an external view of the wax mold according to the present embodiment. It is sectional drawing of the wax shaping | molding die concerning this Embodiment. It is sectional drawing with which it uses for description of the placing piece type of the wax shaping | molding die which concerns on this Embodiment. It is process drawing of the lost wax casting method which concerns on this Embodiment. It is a schematic diagram with which it uses for description of the manufacturing method of the lower mold | type of the wax mold which concerns on this Embodiment. It is a schematic diagram with which it uses for description of the manufacturing method of the upper mold | type of the wax shaping | molding die concerning this Embodiment.

  Hereinafter, a wax mold and a lost wax casting method according to an embodiment of the present invention will be described with reference to the drawings. However, in the drawings, the same or similar reference numerals are given to the same or similar members and parts. Further, the drawings are schematically shown and do not necessarily match actual dimensions and ratios. Furthermore, the drawings may include portions having different dimensional relationships and ratios.

  First, the configuration of the wax mold according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an external view of a wax mold according to the present embodiment. FIG. 2 is a cross-sectional view of the wax mold according to the present embodiment. FIG. 3 is a cross-sectional view for explaining the placing piece type of the wax forming die according to the present embodiment.

  As shown in FIGS. 1 and 2, the wax mold 100 according to this embodiment mainly includes a lower mold 11, an upper mold 12, a gate pipe 30, a feeder pipe 40, and a deaeration pipe 50.

  The lower mold 11 and the upper mold 12 define a cavity 20 as a molten wax injection space. The cavity 20 is formed in an inner shape corresponding to the outer shape of a prototype (not shown). The lower mold 11 and the upper mold 12 of the present embodiment are preferably manufactured using a resin material such as a silicon resin or an epoxy resin, but are not limited to the illustrated resin material. The resin material is cured by allowing it to stand for about 8 to 12 hours by mixing a curing agent. As the resin material, for example, a material that can observe the behavior of the molten wax in the cavity 20 from the appearance in a state where the resin material is cured, such as milky white silicone resin, is preferably selected. In order to improve the releasability of the wax (WAX) solidified in the cavity 20, it is preferable to employ an oil breath type resin material having good lubricity.

  It is preferable to dispose a reinforcing material 60 for preventing the bending of the resin material at portions other than the cavity 20 of the lower mold 11 and the upper mold 12. Examples of the reinforcing member 60 include a reinforcing bar and a metal pipe.

  In addition, as shown in FIG. 3, when the wax model molded by the wax molding die 100 according to the present embodiment has the undercut portion 21, between the resin lower mold 11 and the upper mold 12, A placing piece mold 13 for forming the undercut portion 21 may be provided. Here, the “undercut portion” refers to a portion that has a product shape that cannot be released by the opening / closing direction of the wax mold 100 or by extruding, and that is the cause.

  The mold matching surfaces where the lower mold 11 and the upper mold 12, the lower mold 11 and the placing piece mold 13, the placing piece mold 13 and the upper mold 12, and the placing piece molds 13 are in contact with each other are for positioning purposes. It is preferable to form the uneven portion 14. The concavo-convex shape portion 14 of the present embodiment is formed by, for example, a corrugated concavo-convex portion in which gradual concavo-convex portions are connected, and if positioning can be performed while positioning can be prevented, It is not limited to the illustrated corrugated uneven portion.

  The gate pipe 30 is an inlet for pouring molten wax into the cavity 20, and penetrates the resin upper mold 12 to reach the cavity 20. The upper end portion of the gate pipe 30 is, for example, a concave-shaped nozzle receiving portion whose diameter is increased so that an injection nozzle (not shown) can be easily inserted. The gate pipe 30 of the present embodiment is preferably formed of a metal pipe (pipe) such as a stainless steel pipe, a copper pipe, a brass pipe, or an aluminum pipe. By adopting a metal pipe as the gate pipe 30, it is possible to withstand repeated pouring, and the resin material constituting the upper mold 12 can be reinforced.

  The feeder tube 40 is a feeder part for allowing the molten wax to spread over a portion in the cavity 20 where shrinkage cavities are likely to occur. The shrinkage nest is generated when the molten wax becomes smaller than the volume of the cavity 20 due to solidification / shrinkage, and is easily generated particularly in a portion having a large thickness. Therefore, the feeder pipe 40 is provided at a position where shrinkage cavities are likely to occur at a position separated from the gate pipe 30, and penetrates the resin upper mold 12 to the cavity 20. As with the gate pipe 30, the feeder pipe 40 of the present embodiment is preferably formed of a metal pipe (pipe) such as a stainless steel pipe, a copper pipe, a brass pipe, or an aluminum pipe. By adopting a metal pipe as the feeder pipe 40, it is possible to withstand repeated pouring and to reinforce the resin material constituting the upper mold 12.

  The deaeration pipe 50 forms an air vent hole for venting air from the gas reservoir in the cavity 20. A plurality of deaeration pipes 50 are provided in the portion where the gas accumulation of the cavity 20 is likely to occur, and penetrates the upper mold 12 made of resin. The deaeration tube 50 of the present embodiment is preferably formed of a metal tube (tube) such as a stainless steel tube, a copper tube, a brass tube, or an aluminum tube. By adopting a metal tube as the deaeration pipe 50, a plurality of through holes reaching the cavity 20 are formed in the resin upper mold 12, and the metal tubes are inserted through the through holes, so that the air vent hole can be made very easily. Can be formed. Alternatively, if the tip of the degassing tube 50 made of metal tube is sharpened and press-fitted through the resin upper mold 12 from the pointed tip, and the compressed air is blown into the degassing tube 50, the degassing tube The resin material remaining in 50 can be blown away.

  In addition, it is preferable to employ | adopt colored wax, such as wax green and wax red, for example as the wax (WAX) inject | poured in the cavity 20 of the wax shaping | molding die 100 which concerns on this Embodiment. By employing the colored wax, for example, when the wax mold 100 is formed of milky white silicone resin, it is possible to observe the behavior of the molten wax in the cavity 20 from the appearance of the wax mold 100.

  Next, with reference to FIG. 1 to FIG. 6, the lost wax casting method according to the present embodiment will be described together with the operation of the wax mold 100 according to the present embodiment. FIG. 4 is a process diagram of the lost wax casting method according to the present embodiment. FIG. 5 is a schematic diagram for explaining a method for producing the lower mold of the wax mold according to the present embodiment. FIG. 6 is a schematic view for explaining a method for producing the upper mold of the wax mold according to the present embodiment.

  As shown in FIG. 4, the lost wax molding method according to the present embodiment includes a process for producing a prototype, a process for producing a wax mold corresponding to the prototype, a molten wax injected into the wax mold, and a wax. A process for making a model, a process for making a tree by attaching a plurality of wax models to a sprue runner, a coating process for making a mold by immersing the wax model in a binder and attaching refractory sand, and a process in the mold A dewaxing process that melts and removes the wax mold, a process of firing the mold, a casting process that pours molten metal into the cavity of the mold, a mold releasing process that breaks the mold and takes out the casting, and a casting At least a finishing process for machining and adjusting individual products. Specifically, each process is implemented as follows.

  First, as shown in FIG. 4, a step of producing a prototype is performed (S101). In the step of producing a prototype (S101), the prototype is produced using viscosity, gypsum, wax, wood, or the like. The produced prototype is divided into two prototype pieces 10A and 10B so as to correspond to the lower mold 11 and the upper mold 12 (see FIGS. 5 and 6).

  Next, a process of producing a wax mold 100 according to the prototype is performed (S102). In the step of producing the wax mold 100 (S102), the lower mold 11 and the upper mold 12 are produced based on the divided original pieces 10A and 10B.

  Specifically, as shown in FIG. 5 (a), the divided surface of the original piece 10A is placed face down on the bottom plate 81 of a formwork 80 such as wood or a metal plate. It is preferable to apply a release agent to the surface of the prototype piece 10A. Further, a reinforcing material 60 is disposed in the formwork 80. Next, as shown in FIG. 5B, for example, a curing agent is mixed in a resin material such as silicon resin, and the bubbles are sufficiently removed to fill the mold 80. At this time, if the corrugated uneven shape 14A is provided on the surface of the bottom plate 81, the corrugated uneven portion 14 for positioning can be produced on the mold matching surface. After leaving for about 8 to 12 hours, as shown in FIG. 5C, the mold 80 is released to remove the original piece 10A, whereby the lower mold 11 having the lower cavity 20 is completed.

  Further, as shown in FIG. 6A, the divided surface of the original piece 10 </ b> B is arranged face down on the bottom plate 81 of the mold 80. It is preferable to apply a release agent to the surface of the prototype piece 10B. Further, the gate pipe 30, the feeder pipe 40, and the reinforcing material 60 are disposed in the mold 80. Next, as shown in FIG. 6B, for example, a curing agent is mixed in a resin material such as silicon resin to sufficiently remove bubbles and fill the mold 80. At this time, if the corrugated uneven shape 14A is provided on the surface of the bottom plate 81, the corrugated uneven portion 14 for positioning can be produced on the mold matching surface. After leaving for about 8 hours to 12 hours, as shown in FIG. 6C, the mold 80 is released to remove the original piece 10B, whereby the upper mold 12 having the upper cavity 20 is completed. The deaeration pipe 50 is formed by forming a plurality of through holes reaching the cavity 20 in the upper mold 12 made of resin, and inserting a metal tube into each of the through holes. Alternatively, the tip of the degassing tube 50 made of metal tube is sharpened and press-fitted so as to penetrate the upper mold 12 made of resin from the pointed tip side, and compressed air is blown into the degassing tube 50 so that the degassing tube 50 It can be formed by blowing away the resin material remaining inside.

  Next, a process of injecting molten wax into the wax mold 100 manufactured by the procedure of FIGS. 5 and 6 to manufacture a wax model is performed (S103). As shown in FIGS. 1 and 2, the lower mold 11 and the upper mold 12 are aligned by aligning the edges of the lower mold 11 and the upper mold 12 and positioning the corrugated concave / convex shape portion 14 as a reliance. To do. When the placement piece mold 13 exists, after placing the placement piece mold 13 on the lower mold 11, the upper mold 12 is placed (see FIG. 3). Molten wax is injected from the gate pipe 30 and the hot water is injected up to the hot water pipe 40 in order to prevent shrinkage due to solidification shrinkage. When the wax solidifies, the lower mold 11 and the upper mold 12 are released, and the wax model is taken out.

  Further, a step of producing a wax tree by producing a plurality of wax models and attaching the plurality of wax models to the gate runner with an adhesive or the like (S104). By producing a wax tree, a plurality of castings can be cast simultaneously. Then, the wax tree is immersed in a binder (slurry), and refractory sand (stucco) is attached to the surface of the wax tree to perform a coating process step for producing a tree mold (S105). The coating treatment step (S105) is repeated, and refractory sand is adhered to a desired thickness.

  Next, a dewaxing process is performed to melt and remove the wax tree mold in the mold (S106). In the dewaxing treatment step (S106), for example, the mold is heated with high-temperature and high-pressure steam to melt the wax tree mold in the mold. A cavity formed in the mold by the dewaxing process becomes a cavity into which molten metal is cast.

  Further, a step of firing the tree-shaped mold is performed (S107). In the firing step (S107), for example, firing is performed at a temperature of about 1000 ° C. in a heating furnace. Since the adhesive is solidified by firing the mold, the strength of the mold increases and impurities are removed.

  Next, a casting process of pouring molten metal into the mold cavity is performed (S108). In the casting step (S108), the spout of the fired tree-shaped mold is supported with sand or the like filled in the frame, and molten metal is poured into the mold cavity. After the molten metal is solidified, a mold breaking process is performed to break the mold and take out the casting (S109). When the mold releasing step (S109) is performed, a plurality of castings with a tree-like gate system are taken out.

  Then, a finishing process is performed in which the casting is machined to adjust individual products (S110). That is, in the finishing process (S110), unnecessary parts such as a sprue system and burrs are cut and cut, drilled, and the like to finish a desired product shape. If necessary, for example, surface treatment such as aluminized treatment may be performed.

  Furthermore, it is preferable to perform a step of heat-treating the product (S111). By heat-treating, a tough product can be obtained by adjusting to a desired metal structure. In addition, it is preferable to perform a step of inspecting the product (S112). The reliability of product quality can be improved by performing visual inspection and dimensional inspection of the presence or absence of casting defects such as shrinkage.

  As described above, according to the present embodiment, since the wax mold 100 is molded from a resin material, the production time and production cost of the wax mold 100 can be reduced. Specifically, the production time of the conventional mold is about 30 to 45 days, but the resin wax mold 100 can be manufactured in about 15 days. In addition, when the production cost of the conventional mold exceeds about 1 million yen, it can be produced at about half a million yen.

  Thus, the resin-made wax mold 100 can reduce the production time and production cost, and is suitable for the production of a small variety of products. Even if the design changes in the original mold, the resin-made wax mold 100 has a short mold production time and low production costs, so it is easy to respond quickly to the design change. Furthermore, since the resin wax mold 100 is lightweight, it can be easily moved and handled.

Moreover, when a wax model is formed by using a gypsum material mainly composed of calcium sulfate (CaSO ₄ ) to produce a wax model, it is suitable mainly for lost wax casting of aluminum and aluminum alloys. On the other hand, when producing a wax model with the resin-made wax mold 100 according to the present embodiment, in addition to aluminum and aluminum alloy, lost wax casting of various metals and alloys such as cast iron, copper, bronze, brass, etc. Suitable for
[Other Embodiments]

  The preferred embodiments of the present invention have been described above, but these are examples for explaining the present invention, and the scope of the present invention is not intended to be limited to these embodiments. The present invention can be implemented in various modes different from the above-described embodiments without departing from the gist thereof.

  That is, in the above embodiment, for example, a reinforcing bar or a metal pipe is used as the reinforcing member 60. The reinforcing material 60 is not limited to these metal materials, and for example, a material obtained by attaching a heat resistant material around a hard resin material having high mechanical strength such as a polypropylene resin pipe or a urethane resin pipe may be adopted. .

  Further, as shown in FIG. 3, a metal mold frame member 90 may be disposed around the wax mold 100 in order to prevent the mold of the wax mold 100 from bulging or bending.

10A, 10B prototype,
11 Lower mold,
12 Upper mold,
13 Place piece type,
20 cavities,
21 Undercut part,
30
40 feeder pipe,
50 deaerator,
60 reinforcements,
100 Wax mold.

Claims (6)

A lower mold and an upper mold made of a resin for defining a cavity;
A gate pipe extending through the resin upper mold to reach the cavity;
A hot water pipe that is provided at a position where shrinkage nests are likely to occur at a position separated from the gate pipe, penetrates the resin upper mold and reaches the cavity,
A deaeration pipe provided in a portion where the gas accumulation of the cavity is likely to occur, and penetrating the resin upper mold;
A wax molding die comprising:   The wax mold according to claim 1, wherein the gate pipe, the feeder pipe, and the deaeration pipe are formed of a metal tube.   The wax molding according to claim 1 or 2, wherein a resin placing piece mold for molding an undercut portion is disposed between the lower mold and the upper mold. Type.   The wax forming die according to any one of claims 1 to 3, wherein an uneven shape portion for positioning the die is formed on a die matching surface where the die come into contact with each other.   The reinforcing material for preventing the bending of the resin material is disposed in a portion other than the cavity of the lower mold and the upper mold, according to any one of claims 1 to 4. Wax mold. Producing a prototype; and
Producing a wax mold according to the prototype;
Injecting molten wax into the wax mold to produce a wax model;
Attaching a plurality of wax models to a gate runner to produce a tree;
A coating treatment step of making a mold by immersing the wax tree in a binder and attaching refractory sand;
A dewaxing process for melting and removing the wax tree in the mold;
Firing the mold;
A casting step of pouring molten metal into the mold cavity;
A mold releasing step of breaking the mold and taking out the casting;
A finishing process for adjusting the individual products by machining the castings;
Having at least
The lost wax casting method, wherein the wax mold is formed by the resin wax mold according to any one of claims 1 to 5.