JPH0794065B2 - Unframed method of organic self-hardening mold - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open frame of an organic self-hardening mold formed by mixing an organic self-hardening resin, a curing agent and the like.

[0002]

2. Description of the Related Art A molten metal is cast into a mold made of casting sand in which an organic self-hardening resin and a curing agent are mixed with silica sand, and is left standing for cooling for a required time. Then, a vibrating device is used for separating the casting and the casting sand from the open frame. A vibrating frame unraveling machine was attached. Therefore, when the mold was unframed, a lot of noise and vibration and a lot of dust were generated, which significantly deteriorated the working environment.

FIG. 4 shows a conventional method for breaking the frame of an organic self-hardening mold. In the conventional unraveling method shown in FIG. 4, the molten metal is cast, and the mold 11 which has been left standing and cooled for a required time is lifted by a ceiling crane or hoist 13 and then surrounded by a dust collecting hood 14 directly connected to a dust collector. While vibrating lightly on the table of the vibration-type unraveling device 15 to which the device is attached, the vibration-type unraveling device 15 is operated to separate the casting frame from the molding sand and the casting.

[0004]

In the above-mentioned conventional method, the table of the vibration type unraveling device and the flask are brought into contact with each other during the unraveling, so that there is a problem that noise of 90 to 130 phons is generated. In addition, since a large amount of dust is generated when noise is generated, recently, the number of factories that install dust-collecting hoods and dust collectors that also function as soundproofing and dust-collecting is increasing. It is one of the biggest causes of environmental degradation. On the other hand, vibrations caused by the vibrating unwinding device are also exerting various adverse effects on the processing accuracy of the surrounding machine factories and the living environment in the residential area.

The present invention has the conventional problems such as deterioration of the environment due to dust and deterioration of the environment due to noise when unraveling the organic self-hardening mold, further improvement of the safety of the unraveling work, and realization of mechanization of the unraveling work. It is intended to provide an open-frame method for an organic self-hardening template that can significantly solve the problems.

[0006]

Means for Solving the Problems The method for unraveling an organic self-hardening mold according to the present invention comprises the following means. (1) In an organic self-hardening mold made of molding sand made by kneading an organic self-hardening resin and a curing agent, etc. into silica sand, mold the molten metal, leave it for a required time and cool it, and then cast it from the casting frame and molding sand. In separating the mixture, an aqueous alcohol solution or an aqueous solution containing a surfactant is permeated into the template, and after permeating the template, the template is heated. (2) In the method of (1), furan resin, phenol resin, etc. are used as the organic self-hardening resin added to silica sand or the like. (3) In the means of (1) above, organic sulfonic acid or the like is used as a curing agent (catalyst). (4) In the means of (1) above, an alcohol aqueous solution having a concentration of 5 to 50%, such as methanol, ethanol, isopropyl alcohol, etc., is used to permeate the template. (5) In the method of (1) above, an aqueous solution containing a surfactant is used in which the amount of the surfactant mixed is 0.01 to 0.1% with respect to water. (6) Heating the mold impregnated with the alcohol aqueous solution or the surfactant-containing aqueous solution at 100 to 300 ° C. (7) After permeating an aqueous alcohol solution or an aqueous solution containing a surfactant, or after heating the permeated mold, a pressure-type unraveling device is used as an auxiliary means for unraveling.

[0007]

In the present invention, the molten metal is cast into a mold formed by using a molding sand to which an organic self-hardening type resin and an organic sulfonic acid type curing agent are added, and after standing for a required time and cooling, all or part of the mold is cast. , An aqueous alcohol solution or an aqueous solution containing a surfactant is permeated to weaken the caking force of the template. Then, after this mold is rapidly heated in a short time to evaporate the alcohol aqueous solution or the surfactant-containing aqueous solution and to fill the space between the mold sand grains, the mold strength is 1/5 of that immediately after cooling the mold. It can be reduced to 1/10. When a separating device such as a pressurizing device, which is an auxiliary means for unraveling the frame, is used in a state where the mold strength is remarkably reduced, noise vibration and dust generation are almost eliminated, and the deterioration of the working environment is greatly improved.

[0008]

EXAMPLES Examples of the present invention

FIG. 1 will be described. (A) shows a state in which the core 5 is set in the lower mold 1b shaped by casting the furan molding sand 2 in the molding frame 1, the upper mold 1a is covered, and the molten metal m is poured and cast. . After leaving for a required time until the molten metal solidifies, the upper mold 1a is removed (see FIG. C). (D) shows a state in which an ethanol 20% aqueous solution is sprayed onto the removed upper mold 1a through the spraying device 7 in the vicinity of the permeation promoting holes 3 on the upper surface of the mold (also from the lower surface in some cases).

In (E), the upper mold 1a was inserted into the mold heating furnace 8 and rapidly heated at 170 ° C. for about 5 minutes at the time when the 20% aqueous solution of ethanolol penetrated into the sand grain gaps of the mold. At this time, the mold strength is reduced to about 1/10 of the room temperature coercive force before the treatment as shown in FIGS. Therefore,
After being taken out from the mold heating furnace 8 as shown in (F), the upper surface of the mold is pressed by the pressing device 9, so that the furan molding sand 2 can be separated from the mold frame very easily.

While the above description has explained the separation of the foundry sand 2 of the upper mold 1a, the lower mold 1b is taken out of the cast article 4 as shown in (B) and then inverted to the above (C) and (D). ，
This is carried out in the same manner as in (E) and (F).

FIG. 2 is a graph showing the relationship between the test conditions and the coercive pressure when the heating conditions during the furan sand test immersed in an aqueous alcohol solution with different alcohol concentrations were changed. There is a drop in pressure,
In an economical embodiment, it is preferably 20% within the range of 5 to 50%.
It can be seen that the percentage of% appears to be the most effective reduction compared to the others.

FIG. 3 is a graph showing the relationship between the test conditions (mainly the temperature) and the coercive pressure of a furan sand test piece immersed in a 20% alcohol aqueous solution.
It can be seen that although the coercive pressure decreases proportionally up to 0 ° C, the effective temperature at which it rapidly decreases is in the range of 170 ° C to 200 ° C.

[0013]

The present invention is carried out as described above, and has the following excellent operational effects. (1) In the unraveling work, there is almost no noise, dust, or vibration that significantly deteriorates the environment, and the working environment can be greatly improved. (2) It is possible to shorten the work time for the solution frame. (3) It is possible to automate the solution work and save labor. (4) The safety of unraveling work is improved. (5) Damage (bending, deformation, cracking) of the solution frame is drastically reduced, and casting precision can be improved.

[Brief description of drawings]

FIG. 1 is a process explanatory diagram of a method of the present invention.

FIG. 2 is a graph showing the relationship between the test conditions and the resistance force when the heating conditions of the furan sand test pieces immersed in the alcohol aqueous solution in which the alcohol concentration is changed are changed.

FIG. 3 is a graph showing the relationship between test conditions (mainly temperature) and coercive pressure of a furan sand test piece immersed in a 20% alcohol aqueous solution.

FIG. 4 is an explanatory diagram of a conventional method.

[Explanation of symbols]

1 Casting Frame 2 Casting Sand 4 Casting 7 Spraying Device 8 Mold Heating Furnace 9 Pressurizing Device

Claims (7)

[Claims] 1. A mold made by adding an organic self-hardening resin and a curing agent to silica sand, and kneading the mixture into a molding sand, and then casting the molten metal and leaving it to cool for a required time, and then removing the casting and the molding sand from the flask. A method for breaking the frame of an organic self-hardening mold, characterized in that an alcoholic aqueous solution or an aqueous solution containing a surfactant is permeated into the mold upon separation, and then the mold is overheated. 2. The method for unraveling an organic self-hardening mold according to claim 1, wherein the organic self-hardening resin is a furan resin or a phenol resin. 3. The method for unraveling an organic self-hardening mold according to claim 1, wherein the curing agent (catalyst) is organic sulfonic acid or the like. 4. The method for breaking the frame of an organic self-hardening mold according to claim 1, wherein the concentration of the aqueous alcohol solution such as methanol, ethanol, isopropyl alcohol, etc., which permeates the mold is 5 to 50%. 5. The mixing amount of the surfactant in the aqueous solution containing the surfactant to be permeated into the mold is 0.01 by weight with respect to water.
The method for unraveling the organic self-hardening mold according to claim 1, which is ˜0.1%. 6. The heating temperature of the mold impregnated with an aqueous alcohol solution or an aqueous solution containing a surfactant is 100 to 300 °.
The method for unraveling an organic self-hardening template according to claim 1, wherein the method is C. 7. A mold which has been impregnated with an aqueous alcohol solution or an aqueous solution containing a surfactant, or after the template is heated, a mechanical frame unraveling device such as shock wave, impact, vibration, pressurization or the like is used as an auxiliary means for the template. Item 3. A method for unraveling an organic self-hardening mold according to Item 1.