JPS6336949A - Production of mold - Google Patents

Abstract

PURPOSE:To easily obtain a hollow casting mold having an intricate shape by rolling over a sand magazine upward so that the silica sand coated with a thermosetting resin in the magazine falls by gravity into the cavity of a metallic mold thereby packing the sand into the cavity. CONSTITUTION:The shell coated sand 7 in the sand magazine 6 is packed by gravity into the cavity 2 when the metallic mold 1 and the sand magazine 6 are held connected and are rolled over 180 deg. in this state. The curing of the shell coated sand 7 packed in the cavity 2 is progressed by heat from the surface in contact with the metallic mold 1 and the sand sticks to the inside surface of the cavity 2 when the shell coated sand is held in this state for the specified time by energizing a heater to generate heat. A cured casting mold layer 10 is formed on the inside surface of the cavity 2 and the unreacted sand 7 which does not cure is returned by gravity into the sand magazine 6 when the metallic mold 1 and the magazine 6 are integrally rolled over 180 deg.. The hollow casting mold 11 having a prescribed thickness is thereby produced in the cavity 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing hollow molds using silica sand coated with a thermosetting resin.

Conventional technology A hollow mold using silica sand coated with thermosetting resin
: As a method of forming, a method using a mandrel, a method in which sand is removed by inverting the mold, etc. are known.

Disadvantages that the invention seeks to solve In the former method using a mandrel, the structure of the mold becomes complicated due to the use of the mandrel, and a mechanism for attaching and detaching the mandrel to the molding machine is required. The entire implementation apparatus is complex and expensive.

In the latter method, which involves inverting the mold and discharging the sand, the thickness of the silica sand coated with thermosetting resin that adheres to the mold becomes uneven, resulting in uneven mold wall thickness. ,
It is difficult and expensive to recover the waste sand discharged by inverting the mold.

In both methods, if the mold has a complicated shape, the mandrel or the mold will have an extremely complicated shape.Since the silica sand coated with thermosetting resin will not adhere uniformly to the mold, it will not be possible to make it hollow.
It is not possible to manufacture hollow molds with complex shapes.

A larger means for solving the problem and a working cavity 2'f: A mold 1 having a mold 1 and a sand magazine 6 filled with silica sand coated with a thermosetting resin are connected to the inside of the sand magazine 6. In this state, the mold 1 and the sand magazine 6 are connected so as to be connected, and in this state, the mold 1 and the sand magazine 6 are rotated and heated for a certain period of time with the mold 1 facing downward, and then the mold 1 is turned upward. By rotating the mold, silica sand is reliably filled into a cavity 2 having a complicated shape, thereby making it possible to easily manufacture a hollow mold having a complicated shape.

Example mold 1ri is made up of a pair of split molds 1α, 1α, and has a cavity 21FI having the same shape as the mold, and this cavity 2 has two openings 3.3 open on one side. and a heater 4 near the cavity 2.
The mold 1 is connected to a rotating shaft 5.

The sand magazine 6 is filled with coated silica sand (hereinafter referred to as shell coated sand) 7 with a thermosetting resin, and has two entrances and exits 6 facing the two openings 3.3. , this sand magazine 6 is the entrance 6
．． 8 and the opening 3.3 communicate with each other and are crimped and connected via the heat-resistant seal 9, so that the mold 1 and the sand magazine 6 rotate and oscillate as a unit. be.

This state is shown in FIG. 1, with the mold 1 in the upper position.

As shown in FIG. 2, the mold 1 and the sand magazine 6 are turned over 180 degrees while being connected.

As a result, the shell coated sand 7 in the sand magazine 6 is filled into the cavity 2 by its own weight.

In this state, if the heater 4 is made to generate heat and held for a certain period of time, the shell coated sand 7 filled in the cavity 2 will be hardened by the heat from the surface in contact with the mold 1, and
adheres to the inner surface of the

After the above-mentioned certain period of time has elapsed, as shown in FIG. The unreacted shell coated sand 7id returns to the sand magazine 6 under its own weight.

As a result, a hollow mold 11 having a predetermined thickness is manufactured in the cavity 2 as shown in FIG. 11 is obtained.

The thickness of the mold can be adjusted by controlling the holding time in the state shown in Figure 2 above, or by continuously repeating the series of steps shown in Figures 1 to 3 above multiple times. The single-type layer 6 may be formed into a plurality of layers. For example, if the series of steps is repeated twice in succession, the mold no lead 10 becomes 2 NO as shown in FIG.

Further, filling can be performed more efficiently by oscillating the shell coated sand 7 into the cavity 2 at a constant angle of 4σl.

Effects of the invention Since no mandrel is used, the mold structure and molding machine are simplified.

Since the silica sand coated with a thermosetting resin inside the sand magazine 6 is placed above and falls into the cavity 2 of the mold 1 under its own weight and is filled, the sand magazine 6 is placed in the upper direction and is filled into the cavity 2 of the mold 1. can be reliably filled, and hollow molds with complex shapes can be manufactured easily.

Excess silica sand in the silica sand filled in the cavity 2 falls under its own weight into the sand 1 gazine 6 when the mold 1 is placed upward, so there is no need to collect the sand and it can be used repeatedly, which is advantageous in terms of cost. It is.

By repeating a series of operations multiple times in succession, the thickness of the mold can be easily controlled.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1, FIG. 2, and FIG. 3 are process explanatory diagrams, FIG. 4 is a sectional view taken along the line ■-IV of FIG. 1, and FIG. 3 is a sectional view taken along the line ■-v in FIG. 3. FIG. 1 is the mold, 2 is the cavity, 6 is the sand magazine, and 7 is the shell coated sand. Jaw Man Komatsu Rakusakusho Co., Ltd.

Claims (1)

[Claims] A mold 1 having a cavity 2 and a sand magazine 6 filled with silica sand coated with a thermosetting resin are connected so that the cavity 2 and the inside of the sand magazine 6 communicate with each other, and in this state, the mold 1 and A mold manufacturing method characterized in that the mold 1 is rotated integrally with a sand magazine 6 and held for a certain period of time while being heated, and then rotated so that the mold 1 is facing upward. .