JPS63299842A - Method for stabilizing surface of green sand - Google Patents

Abstract

PURPOSE:To harden and stabilize surface of green sand for a short time by beforehand sticking ultraviolet ray hardenable resin on the surface of the green sand by atomization, etc., and after that, irradiating the ultraviolet ray. CONSTITUTION:In the figure, a mold 1 is a molded green sand (molding sand 3) in an upper flask 5 as a cope and a mold 2 is a molded green sand (molding sand 4) in an lower flask 6 as a drag. On the surface of this green sand, the ultraviolet ray hardenable resin adding reactive dilute agent, photo-polymerized starting agent and the other additive compensating for weakness of sand grain binding to epoxy resin or polyester resin or urethane resin, etc., having acrylate radical (acrylic acid salt), which is polymerized hardened with the ultraviolet ray, is atomized by a nozzle 9. After that, by irradiating the ultraviolet ray with an ultraviolet ray lamp, the surfaces of the green sands 3, 4 are hardened and stabilized for a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for stabilizing the surface of shaped earth and sand by hardening and stabilizing the surface of the earth and sand.

(Conventional technology) Foundry sand containing a caking agent for making molds is
en 5and). Conventionally, methods for hardening and stabilizing the surface of the earth and sand 21 in casting as shown in FIG. A method of spraying a phenolic resin or a method of drying the surface of the earth and sand 210 is used.

Note that there are no documents specifically related to this technology.

(Problems to be Solved by the Invention) However, in the above conventional method, it takes a long time for K to harden the surface, and if the time is long, the surface of the mold not only dries but also hardens. During this period, there were problems such as dirt adhering to the surface. Further, even when cured, the degree of curing was insufficient, the stability of the surface was poor, and the stabilization of curing was not sufficient. For example, when marking is done with a laser on the surface of insufficiently hardened earth and sand, there are problems in that the contours of the characters become unclear and the bottoms of the characters become uneven, making them difficult to read, as shown in Figure 7 (5).

The present invention is intended to solve this problem, and it is an object of the present invention to provide a method for stabilizing the surface of earth and sand that can quickly and stably harden the surface of earth and sand during a casting process.

(Means for Solving the Problems) The present invention, as a means for solving the above-mentioned problems, applies or sprays an ultraviolet curable resin to the surface of the shaped earth and sand, and then irradiates the earth and sand with ultraviolet rays.・Harden the surface of
It is characterized by stabilization.

As the ultraviolet curable resin, it is desirable to use synthetic resins such as epoxy, polyester, and urethane as the main material, which have a group having an ethylenic double bond at the end of the molecule that polymerizes and cures with ultraviolet light having a wavelength of 300 to 400 nm. .

(Function) In the casting process, if a mold for casting is formed with earth and sand, an ultraviolet curable resin is applied or sprayed to desired areas or the entire surface of the mold, and then irradiated with ultraviolet rays, the resin will be cured and stabilized in a short time. Therefore, the hardened and stable surface is engraved with a laser or the like, and then cast using a conventional method.

(Example) Next, one embodiment of the present invention will be described based on FIG.

In FIGS. 1(a) and 1(b), 1 and 2 are molds for producing castings, and 5.4 is foundry sand used to make the molds 1.2. This foundry sand 3.4 is made by adding a caking agent to foundry sand and giving it a caking force by mixing K, and is called earth and sand. Mold 1 in Figure 1 (a) is earth and sand (molding sand 3) molded as an upper mold in the upper frame 5, and mold u2 in Figure 1 (b) is earth and sand (molding sand 4) molded as a lower mold in the lower frame 6. ). In the figure, 7 is a sprue, 8 is a mold space, and 9 is a nozzle provided at an arbitrary position to spray a resin that polymerizes and hardens from ultraviolet MK on the surface K of earth and sand. 10 is an ultraviolet lamp that irradiates the earth and sand to harden the surface of the earth and sand.

On the surface of such earth and sand, reactive diluents, photopolymerization initiators, and others such as sand grains are added to epoxy resins, polyester resins, or urethane resins having acrylate groups that are polymerized and cured by ultraviolet rays with a wavelength of VC 300 nm to 400 nm. Additives that compensate for bonding defects,
is applied or sprayed by nozzle 9 and then UV lamp 10 (ultraviolet lamp)
When UV rays are irradiated from K, the surface of the earth and sand 3.4 hardens and stabilizes within a few seconds.

In the experiment of this example, photocurable resin TB3051 manufactured by Three Bond Co., Ltd. was used, and when it was irradiated with an sKW UV lamp from a distance of 10 degrees, it completely solidified within 5 seconds.

In addition, in order to check the hardening state, K, the number of digits required for the surface of this hardened earth and sand, as shown in Figures 2 and 3, are shown in 5.
The characters are combined and engraved with a laser (indicated path), the upper frame 5 and the lower frame 6 are combined to form one set of molds as shown in Fig. 4, and the mold is poured into the mold space 8. As shown in the figure, it was possible to emboss small characters, for example, about 385 m 1 m in size, on the product 11 with bright 8AK.

The data for laser engraving is as follows.

(Effects of the Invention) As explained above, according to the method for stabilizing the surface of earth and sand according to the present invention, ultraviolet curable resin is attached to the surface of earth and sand by spraying or the like, and then ultraviolet rays are irradiated to stabilize the earth and sand. The surface hardens and stabilizes in a matter of seconds.

This allows clear markings to be made and quick casting work.

Furthermore, the curing time is shortened, which eliminates the adhesion of dirt, and this hardened and stabilized sand can be used for cores, which are often made of shell sand, expanding the range of uses for earth and sand as sand cores. It has a good effect.

[Brief explanation of the drawing]

Figure 1 (a) is a perspective view showing the upper mold of a mold sprayed with resin being irradiated with ultraviolet rays in one embodiment of the present invention, and Figure 1 (b) is a perspective view of the mold sprayed with resin. A perspective view showing the lower mold being irradiated with ultraviolet rays, Figure 2 is a perspective view showing the laser engraving on the dirt of the lower mold, and Figure 5 is the second
Figure 4 is an enlarged view of the laser engraving, and Figure 4 is a sectional view showing how the upper frame and lower frame are combined to form one set of molds.
Fig. 5 is a perspective view showing the engraved product, Fig. 6 is a perspective view showing laser engraving on the earth and sand of the conventional lower die, and Fig. 7 is an enlarged view showing the conventional laser engraving of earth and sand. . 3 , 4 =・-・−Green sand Figure 1 (A) (B) Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 @ Figure 7

Claims (1)

[Claims] A method for stabilizing the surface of earth and sand, which comprises applying or spraying an ultraviolet curable resin onto the surface of shaped earth and sand, and then irradiating the resin with ultraviolet rays to harden and stabilize the surface of the earth and sand.