JPH02211932A - Molding method for green sand mold - Google Patents

Abstract

PURPOSE:To improve strength at edge part by blowing green sand into a cavity demarcated with a recessed part in a lower mold pattern and a preliminary upper mold pattern having at least width size smaller than the normal width size, separating the upper mold pattern and compressing a preliminary forming body downward with the upper pattern having the normal size. CONSTITUTION:By descending the preliminary upper mold pattern 5, the cavity is demarcated with the recessed part 2 in the lower mold pattern 1, and the green sand is blown into the cavity from a blowing hole 6, and after completing the blowing, the preliminary upper mold pattern 5 is separated from the lower mold pattern 1 and a scended to form the preliminary forming body. Successively, by inserting the upper mold pattern 9 into the recessed part 2 in the lower mold pattern 1, the preliminary forming body is compressed to the vertical direction and at the same time, this is also compressed to the horizontal direction with size difference of the horizontal direction of a pattern part 8 and a pattern part 11 to make the edge part strong. After completing the compression, a releasing pin 3 is ascended through pushing out plate 4 and the green sand is separated and ascended from the recessed part 2 to obtain the green sand mold. By this method, density of the edge part becomes high, and the strength is improved and collapse of the edge part is prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an improvement in a green sand mold manufacturing method.

(Prior art and issues) Conventionally, in the mold making method in which green sand filled in a casting flask on a surface plate was compressed in an upper mold to form a green mold, the flat surface of the parting surface of the green sand mold There was a problem in that the boundaries between the depressions, that is, the edges, were prone to collapse.

The present invention has been made to solve the above problems.

(Means for Solving the Problems) In order to achieve the above object, the green sand molding method of the present invention uses a preliminary upper model having a model portion whose lateral dimension is shorter than the regular dimension. After green sand is blown into the molded cavity and the preliminary upper model is separated to form a preform, the preform is compressed downward by an upper model having a model part of regular dimensions. It is.

(Example) An example will be described with reference to the drawings. In FIG. Release bottle (3) (:
() is suspended so as to be able to rise, and the lower end of the release bin (3) is fixed onto an extrusion plate (4) that is suspended so as to be able to rise on the lower mold (1) via a suspension rod (not shown). has been done. Also,
In Fig. 2, (5) is a preliminary upper model, which is a flanged model mounting plate (7) equipped with an inlet (6) penetrating vertically.
), and a model part (8) fixed to the lower surface of the model part mounting plate (7). The model portion (8) has a horizontal dimension (A') and a vertical dimension slightly smaller than the horizontal dimension (4) and vertical dimension of a regular upper model (9), which will be described later. In Fig. 3, (9) is a regular upper model, which is composed of a flange-attached model part plate (l) and a model part (11) fixed to the lower surface of the model part plate (lO). ing.

In addition, (12) is a guide bin, (13) is a guide bin hole, and (14) is a bushing.

Next, to explain the procedure for molding a frameless green sand mold using the device configured as described above, the preliminary upper mold model (5
) is lowered to define the cavity with the preliminary upper model (5) and the four parts (2) of the lower model (1), and then the air inlet (
Green sand is blown into the cavity from 6), and after the green sand blowing is completed, the preliminary upper model (5) is separated from the lower model (1) and raised to perform preforming as shown by the two-dot chain line in Figure 1. Shape your body. Next, the upper model (9) is replaced with the lower model (1).
At the same time, the preform is compressed in the lateral direction due to the 1υ lateral dimension difference between the model part (8) and the model part (1υ). By compressing the preform in the lateral direction in this way, the so-called edge portions can be strengthened. After the compression of the preform is completed, the mold release bin (3) is passed through the extrusion plate (4).
(3) is raised and compressed and solidified green sand is added to four parts (2).
The desired green sand mold can be obtained by separating and raising the mold.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the edge portions of the so-called green sand mold are actively compressed in the lateral direction as well, which makes it more compact compared to the conventional green sand mold making method. As a result, the density of the edge portion is greatly increased, the strength is improved, and collapse of the edge portion does not occur.

[Brief explanation of the drawing]

The drawings include a lower model used in the present invention and an upper model.

Claims (1)

[Claims] Green sand is blown into a cavity defined by the concave part of the lower model and a preliminary upper model having a model part whose lateral dimension (A') is smaller than the regular lateral dimension (A), and the preliminary upper model is A green sand mold making method, which comprises separating and molding a preform, and then compressing the preform downward with an upper model having a model portion of regular dimensions.