JPH04210848A - Method and apparatus for forming coating film of refractory in lost wax method - Google Patents

Abstract

PURPOSE:To surely prevent the development of defective pattern with respect to dipping work of a wax pattern by making the prescribed stream stirring slurry, and removing mixed foreign matter using net-like catching means. CONSTITUTION:A net-basket 15 suspended in the slurry is arranged near a rotary shaft 13 in a screw 9 for stirring. By rotating a motor 11, the screw 9 for stirring forms the stream SL flowing up from bottom part of a tank 5 to the surface layer part. The net basket 15 is suspended so as to flexibly shift according to this stream SL and naturally keep the state with the opening part 17 opened toward upstream side of the stream. By this method, the foreign matter, whose mixture in the slurry is unforeseen, can be automatically caught and removed in parallel with dipping work of the wax pattern 3 and the development of defective pattern in a mold can be surely prevented.

Description

[Detailed description of the invention]

[00011

[Field of Industrial Application] The present invention relates to a method and apparatus for forming a refractory film in the lost wax method, in which a wax model is immersed in a tank containing a slurry of refractory material to form a refractory film on the surface. In particular, the present invention relates to a method and apparatus for removing foreign matter mixed into slurry. [0002] Conventionally, in the manufacture of various precision parts, molds for precision casting have been frequently manufactured by the lost wax method. This lost wax method includes a step of immersing a wax model in a slurry tank to form a refractory coating on its surface. The slurry contained in the slurry tank consists of a refractory (Zr flour, molten Si, etc.), a binder (colloidal silica, etc.), and water. Further, a liquid draining plate or the like is disposed around the periphery of the slurry tank to receive the slurry liquid dripping from the wax model pulled up after immersion and return it into the tank. [0003]

[Problem to be solved by the invention] However, the slurry in the tank may originally contain large chunks of refractory material, or pieces of wax models may become mixed in during dipping or draining. there were. Furthermore, when this dipping operation is performed multiple times, fragments of the refractory material that was previously attached to the surface of the wax model as a coating and dried and solidified may sometimes become mixed into the slurry liquid. [0004] For this reason, these solidified fragments, large chunks of refractory material, or wax fragments adhere to the surface of the wax model, resulting in so-called inserts and so-called sand traps in which extra spaces are formed in the finished mold. causing the phenomenon of
There was a problem that a mold having the correct shape could not be formed. [0005] Therefore, in the past, foreign matter mixed in the slurry tank was handled manually by occasionally scooping it out with a wire mesh, etc., but in order to perform this work, the continuous dipping work was temporarily interrupted. There was a problem in that work efficiency was poor because it was necessary and required a great deal of labor. [0006] In addition, since the timing and causes of contamination of these foreign substances are not accurately understood, these occasional manual measures cannot reliably remove foreign substances, resulting in defective products. The outbreak had not been properly suppressed. [0007] The present invention was completed with the aim of solving such problems and accurately preventing the occurrence of defective products by efficiently and reliably removing foreign substances. [0008]

[Means and Effects for Solving the Problems] The present invention, which has been made to achieve the above object, provides a wax model that is immersed in a tank containing a slurry of a refractory material to form a refractory coating on the surface. In a method for forming a refractory film using the wax method, a slurry of refractory material contained in a tank is stirred to form a predetermined flow, and the refractory material is mixed into the slurry by a net-like trapping means that opens toward the upstream side of the flow. A configuration is adopted in which the immersion is performed while capturing solids having a predetermined size or more. [0009] According to this method, solids of a predetermined size or more mixed into the slurry flow in the tank according to a predetermined flow, and are captured by the net-like capture means during this flow. In the method of the present invention, the wax model is immersed while capturing these foreign substances, so the work efficiency is not impaired, and it is difficult to know when and how foreign substances are introduced. can be accurately removed from the slurry, and can be reliably prevented from adhering to the surface of the wax model. [001,0] Here, if the predetermined flow formed by stirring is a flow that brings up the surface layer slurry from the bottom of the tank, and the net-like capture means captures the solids that descend near the surface layer of the slurry, the weight It is possible to accurately capture large foreign objects, and it is also possible to prevent heavy foreign objects that have settled in the slurry from somehow rising to the surface and attaching to the wax model. [0011] The present invention has also been completed as an apparatus, which includes a tank containing a slurry of a refractory material to be adhered to the surface of a wax model, and a dipping means for immersing the wax model in the tank. A refractory film forming apparatus using a wax method includes: a stirring means disposed in the tank for stirring the refractory material slurry to form a predetermined flow; The present invention has adopted a configuration characterized in that it is provided with a net-like trapping means disposed in the tank to trap solid matter larger than a predetermined size mixed into the slurry. [0012] The operation is similar to that in the method described above. Then, the stirring means is a screw or the like that forms a flow that brings up the surface layer slurry from the bottom of the tank, and the net-like capturing means is configured to capture the solids that descend near the surface layer of the slurry, so that the surface layer slurry comes up from the bottom of the tank. Both heavy and light foreign objects can be accurately captured. [0013] Furthermore, the net-like trapping means is a box-shaped thing having an upper opening suspended near the inner circumferential surface of the tank,
By immersing the opening edge on the upstream side of the flow deeper into the slurry than the opening edge on the downstream side, this net-like trapping means can flexibly move according to the flow formed by the stirring means, thereby increasing efficiency. It also has an excellent effect of being able to capture foreign matter well and reliably. [0014]

Embodiments Next, embodiments embodying the present invention will be described in detail with reference to the drawings. 1 to 3 show a first embodiment. [0015] The apparatus 1 for forming a refractory film in the lost wax method according to the first embodiment includes a tank 5 containing a slurry of a refractory material to be adhered to the surface of a wax model 3, and a large number of wax models 3 suspended therein. A conveying and dipping device 7 that holds and conveys these wax models 3 to a tank 5 and immerses them one after another, a stirring screw 9 inserted to the bottom of the tank 5, a motor 11 that rotates this stirring screw 9, and a stirring The net cage 15 is suspended in the slurry near the rotating shaft 13 of the screw 9. [0016] A liquid draining plate 5a is disposed at the opening edge of the tank 5, and is configured to drain the slurry liquid dripping from the wax model 3 that has been pulled up. Stirring screw 9
As shown in FIG. 1A, a flow SL is formed that causes slurry to rise from the bottom of the tank 5 to the surface layer. Note that this flow SL does not generate stirring heat,
In addition, the flow velocity and strength are such that no precipitation occurs in the slurry liquid. [0017] Furthermore, the mesh basket 15 has 8 meshes having meshes of 1 to 3 mm square, and has a rectangular parallelepiped shape with an opening 17 at the upper side. This mesh basket 15 has a flow SL of the opening 17, as shown in FIG.
The edge 17a near the upstream side is 20 to 30 mm above the slurry level.
mm in depth, and is suspended in a slightly inclined state so that the opposite edge 17b is at the slurry level. [0018] This refractory film forming apparatus 1 drives the conveying and dipping apparatus 7 while driving the motor 11 to rotate the stirring screw 9 and forming a flow SL rising from the bottom to the surface layer in the slurry. The process of sequentially conveying and immersing the wax model 3, pulling it up, and then drying and solidifying it was repeated 8 to 9 times to form a refractory coating on the surface of the wax model 3. During this time, the pieces of wax that were generated when the wax model 3 was damaged, the pieces of dried and solidified refractory material, and the large chunks of refractory that were originally in the slurry were all captured in the mesh basket 15 and removed from the slurry. Since they could be removed cleanly, these foreign substances did not adhere to the surface of the wax model 3 immersed in the slurry. [0019] As a result, the precision molds manufactured through subsequent processes such as melting and waxing had the correct shape, and no defective products were produced. Furthermore, according to the refractory film forming apparatus 1 of this embodiment, the work of removing foreign matter mixed into the slurry can be carried out automatically in parallel with the work of dipping the wax model 3. Therefore, it is possible to reliably remove these foreign substances, which do not know when they will be mixed in, without impairing work efficiency and without requiring labor. [0020] Furthermore, the mesh basket 15 is movably suspended in the tank 5, and the opening edge 17a on the upstream side of the flow SL formed by the stirring screw 9 is deeper in the slurry than the opening edge 17b on the downstream side. Since the mesh basket 15 is immersed in water, the mesh basket 15 moves flexibly according to the flow SL, and the opening 17 is naturally maintained in an open state toward the upstream side of the flow SL. Therefore, foreign matter is captured extremely smoothly. [00211 In addition, since the stirring screw 9 is deeply inserted into the bottom of the tank 5 to form a flow SL that pumps up the slurry to stir it, heavy foreign objects can also be lifted to the vicinity of the surface layer and captured reliably. It is also possible to prevent heavy foreign matter that had settled in the slurry from somehow coming to the surface and attaching to the wax model 3. [0022]Furthermore, since the opening edge 17b on the downstream side is raised to the slurry liquid level, light foreign objects floating on the liquid surface can be reliably captured. Next, the second embodiment is shown in FIG.
The explanation will be based on. [0023] The second embodiment has the same configuration as the first embodiment, but has a feature in the mesh basket. The mesh basket 21 of the second embodiment has a tapered basket bottom 23, which becomes deeper toward one side plate 25 in the longitudinal direction. This side plate 25 is attached to the car bottom 23 with a hinge so that it can be opened and closed. As a result, the trapped foreign matter can be easily removed by opening the side plate 25. [0024] Furthermore, FIG. 5 shows a third embodiment, in which a mesh basket 31 having a planar arc shape is adopted and arranged to surround the rotating shaft 13 of the stirring screw 9. As a result, the capture efficiency was improved. [0025] Furthermore, FIG. 6 shows a fourth embodiment,
A motor 41 is disposed at the bottom of the tank 5, and a stirring screw 43 disposed at the bottom of the tank 5 stirs the slurry to form a flow SL that rises along the peripheral wall of the tank 5 and descends from the center. A mesh basket 45, which itself is ring-shaped or is arranged in a plurality of ring-shaped cages, is disposed near the surface layer of the slurry along the inner circumferential surface of the tank 5. Similar to the first embodiment, the mesh basket 45 is connected to the opening edge 4 on the upstream side of the flow SL.
5a is placed in a deeply immersed state. According to this embodiment, the open space above the tank 5 can be used freely. In addition, the foreign matter trapping efficiency is high, especially in the tank 5.
This has a high effect of eliminating the presence of foreign matter in the center of the area. [00261 Although the present invention has been described in detail above, the present invention is not limited thereto in any way, and various embodiments can be adopted without departing from the gist thereof. For example, the stirring means may be provided on the side wall of the tank, or the mesh basket may be fixed rather than suspended. [0027] Furthermore, the flow formed by stirring may be formed as a flow that rotates along the inner circumference or as a flow that rises in a spiral shape, and moves along these flows. In order to easily capture the foreign matter, the net-like capture means may be arranged in accordance with these flows, and the flow is not limited to a flow that simply rises from the bottom to the top. [0028] Effects of the Invention 1 As explained above, according to the method for forming a refractory film in the lost wax method of the present invention, foreign matter that may be mixed in at any time can be efficiently and reliably removed, thereby preventing defective products from being molded. can be accurately prevented from occurring. [0029] Furthermore, according to the refractory film forming apparatus of the present invention, the method of the present invention can be concretely realized, and the refractory film forming operation can be performed while automatically removing foreign matter. , the labor and man-hours associated with foreign matter removal can be significantly reduced. [00301 Furthermore, stirring the slurry to remove foreign matter also has the effect of maintaining the slurry in a uniform state suitable for forming a refractory coating. In addition, in a configuration in which a flow is formed that ups the surface slurry from the bottom of the tank, and the solids falling near the surface of the slurry are captured using a net-like capture means, it is possible to accurately capture even heavy foreign particles, and prevent them from settling in the slurry. It is also possible to prevent heavy foreign objects from floating up and attaching to the wax model. Furthermore, light foreign objects floating near the surface layer can also be accurately captured. [00311] Furthermore, by configuring the net-like trapping means near the inner peripheral surface of the tank and having the opening edge on the upstream side of the flow deeper into the slurry than the opening edge on the downstream side, it is possible to This net-like trapping means can trap foreign objects while moving flexibly, and has an excellent effect of being highly efficient in trapping foreign objects.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram including an enlarged view of essential parts of a refractory film forming apparatus according to a first embodiment.

FIG. 2 is a plan view of the refractory film forming apparatus of the first embodiment.

FIG. 3 is a perspective view of essential parts of the refractory film forming apparatus of the first embodiment.

FIG. 41 is a perspective view of the mesh basket employed in the second embodiment. FIG. 5 is an explanatory diagram showing a top view of a refractory film forming apparatus according to a third embodiment and the shape of a mesh basket used therein.

FIG. 6 is a configuration diagram of a refractory film forming apparatus according to a fourth embodiment.

[Explanation of symbols]

1... Refractory material film forming device, 3... Wax model, 5...
...tank, 7...transport dipping device, 9.43...stirring screw, 15,21,31.45...mesh basket,
17a, 45a...Upstream opening edge, 17b...Downstream opening edge.

Claims (5)

[Claims] Claim 1: A method for forming a refractory film in the lost wax method, in which a wax model is immersed in a tank containing a slurry of refractory material to form a refractory film on the surface, the refractory material contained in the tank. The slurry is stirred to form a predetermined flow, and the immersion is performed while capturing solids of a predetermined size or more mixed into the slurry by a net-like capture means that opens toward the upstream side of the flow. A method for forming a refractory film using the lost wax method. 2. The predetermined flow according to claim 1, wherein the predetermined flow is a flow that pushes up the slurry from the bottom of the tank to the surface layer, and the net-like trapping means traps solids that descend near the surface layer of the slurry. A method for forming a refractory film using the lost wax method. 3. An apparatus for forming a refractory material film in a lost wax method, comprising a tank containing a slurry of a refractory material to be adhered to the surface of a wax model, and dipping means for immersing the wax model in the tank, a stirring means disposed in the tank and configured to stir the slurry of the refractory material to form a predetermined flow; 1. An apparatus for forming a refractory film in a lost wax method, comprising a net-like trapping means for trapping solid matter of a predetermined size or more mixed therein. 4. The stirring means is a screw or the like that forms a flow that causes the slurry to rise from the bottom of the tank to the surface layer,
4. The apparatus for forming a refractory film in a lost wax method according to claim 3, wherein the net-like trapping means traps solid matter that descends near the surface layer of the slurry. 5. The net-like capturing means is a box-like member having an upward opening suspended near the inner circumferential surface of the tank,
5. The apparatus for forming a refractory film in the lost wax method according to claim 4, wherein the opening edge on the upstream side of the flow is immersed deeper into the slurry than the opening edge on the downstream side.