JPS62259661A - Core breaking method in die casting - Google Patents

Abstract

PURPOSE:To eliminate the need for a heating stage for a casting after die parting and to permit the easy discharge of sand by supplying air to a core in dies to break the core in the dies prior to die parting at the point of the time when the solidification of the casting by a molten metal is nearly completed. CONSTITUTION:An air feeder 3 having a solenoid valve 8 is provided to the die 1 and the valve 8 is opened and closed via a temp. controller 6 and a timer 7 by the output of a thermocouple 5. The molten metal is poured into the die 1 in which the core 2 is set. The timer 7 operates to open the solenoid valve 8 when the solidification of the casting is nearly completed and the output of the thermocouple 5 coincides with the set temp. of the controller 6. The core 2 collapses in the die 1 when air is introduced into an air passage 2a of the core 2 from an air source 9. The need for the heating stage of the casting after die parting is thereby eliminated and the easy discharge of the sand is permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for collapsing a core in mold #3 construction using a core.

[Conventional technology]

Conventionally, in 2-hour mold making, the core was usually disintegrated after the cast product was released from the mold.

That is, as shown in the outline of the process in Fig. 3, the fired core is set in a mold in the molding process, the mold is closed,
There is a method in which the core is disintegrated by pouring the metal into the mold, releasing the cast product from the mold after it has solidified, and placing it in a heating furnace and heating it, as shown in Figure 4. There is a method in which the cast product is released from the mold in the same manner as in the case of FIG. 3 up to the molding process, and then the core is disintegrated by placing it in an oxygen furnace and heating it.

[Problem that the invention seeks to solve]

However, in conventional mold casting and core collapse methods, after the cast product is released from the mold, the core is heated and collapsed in a heating furnace or an oxygen furnace. Therefore, installing a heating furnace requires a large amount of equipment cost and installation space, and the maintenance and operating costs of these step teeth also increase, leading to a problem in that the production cost at the time of casting rises. Ta.

An object of the present invention is to provide a method for core collapse in full-mold casting that can solve these conventional problems.

[Means for solving problems]

Therefore, the core collapse method in full mold casting 41 according to the present invention supplies air to the core in the mold when the solidification of the cast product by molten metal is almost completed, and the core collapses in the mold before being released. Collapse the core.

[For production]

According to the above method, the hot core in the mold is easily disintegrated due to the carbonization promoted by the supply of air.

〔Example〕

Hereinafter, the present invention will be described based on specific embodiments with reference to FIGS. 1 and 2 of the accompanying drawings.

1 shows a molding bag used for mold casting according to the present invention, in which a core 2 is inserted into a predetermined position within a mold 1. This mold 1 is provided with an intake port 1a and an exhaust port 1h, which are communicated with an air passage 2a provided in the core 2 via an air supply device 3 and an exhaust device 4, respectively.

A thermocouple 5 is attached to the mold 1 so that the temperature of the molten metal can be detected by setting the temperature of the mold near the cast product in dI, and the output of this thermocouple 5 is input to a temperature controller 6. The set temperature is set to a predetermined value at which the solidification of the cast product by the molten metal is almost completed, and at this predetermined temperature, the timer 7 operates to turn on the solenoid valve 8 for a predetermined period of time, and air from the air source 9 is passed through the communication port 1a. The air can be supplied to the air passage 2a of the core 2 via the air supply device 3.

The core 2 is composed of divided cores 2b and 12c that can be divided into upper and lower parts as shown in FIG.
b, :2c are provided with long grooves 2a++2az that face each other and form air passages 2a when assembled.

Here, after the core 2 is completely placed in the mold 1 into the cellar 1, molten metal is injected into the mold 1 from a sprue (not shown).

When the solidification of the cast product by the molten metal is almost completed, the output of the thermocouple 5 matches the set temperature of the temperature controller, the timer is activated, the solenoid valve 8 is opened, and the air source 9 is supplied for a predetermined period of time. of air is supplied into the air passage 2a of the core 2.

This accelerates the carbonization of the core 2, which is still kept at a high temperature, and finally leads to its collapse.

The solidified casting is then released from the mold, but since the core has already collapsed by the time it is released, the conventional heating process using a heating furnace or oxygen furnace is no longer necessary.

A cast product is completed simply by ejecting the sand through vibration.

In the above embodiment, the mold 1 was provided with a dedicated air supply port 1a and an exhaust port 1b that communicated the air passage 2a of the core 2 with the outside, but the air supply port 1a and the exhaust port 1b were provided in the mold 1 to connect the air passage 2a of the core 2 to the outside. It is also possible to use the secondary gas vent hole for these purposes.

〔Effect of the invention〕

As described above, the core collapse method in mold casting according to the present invention supplies air to the core in the mold when the solidification of the cast product is almost completed, and Since the core collapses, there is no need to heat the cast product after release from the mold, and special equipment such as a heating furnace is not required for heating.
The equipment costs, maintenance costs, operating quality, etc. are reduced, and the time required for casting is shortened, which is extremely effective in reducing production costs.

Furthermore, by supplying air into the core, gas generated from the core is promoted to be discharged to the outside.

It also reduces casting defects due to gas generation.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a molding apparatus for full-shape casting used in the present invention. Figures 2 (a) and (b) are perspective views showing the shape of the core when separated and assembled, respectively; Figures 3 and 4 illustrate different core collapse processes in conventional mold casting. It is a process diagram. 1... Mold 2... Core 2a... Air passage 5... Thermocouple 6... Temperature controller 7...
・Timer 8...Solenoid valve S...Air source 1vA Fig. 3 Fig. 4

Claims (1)

[Claims] 1. In mold casting using a core, supplying air to the core in the mold when the solidification of the cast product by molten metal is almost completed to cause the core to collapse in the mold before being released from the mold. A core collapse method in mold casting characterized by: