JPS6316853A - Sand removing method for core sand - Google Patents

Abstract

PURPOSE:To shorten the time for burning sand after removal of core by supplying air for burning a resin and grit for striking and breaking a core to the core sand from the apertures of a casting to remove the core sand near the apertures while the casting is at a high temp. right after casting. CONSTITUTION:The air 9 for burning the resin of the core sand 5 and the grit 10 to break the core sand 5 by applying impact thereto are supplied from the apertures 3, 4 by using blasting guns 7, 8 at the high temp. right after casting of a cylinder head. After the core sand 5 near the apertures 3, 4 is removed by such means, the sand burning of the cylinder head 1 is executed and the remaining core sand 5 is removed. The time required for the sand burning of the cylinder head casting is thereby shortened and the productivity of the casting is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for removing core sand after casting, for example, a cylinder head of a vehicle engine.

(Prior Art) A conventional method for removing core sand after casting rad into a cylinder of a vehicle engine will be described with reference to FIG.

A cylinder head 1 of a typical water-cooled engine is provided with a complex-shaped water passage 2 for circulating cooling water therein. This water channel 2 has two openings 3.4.

The cooling water flows into the opening 3 during engine operation,
The cylinder head 1 is cooled by passing through the inside of the cylinder head 1, and then flows out from the opening 4.

In the middle of the water channel 2, there are provided an outer wall of the intake/exhaust port, an outer wall of the insertion hole through which the intake/exhaust valve is inserted, and a branch cooling water channel for cooling details such as the vicinity of the combustion chamber.

When casting the cylinder head 1 that constitutes the waterway 2 having such a complicated structure, a core 6 made of core sand 5 containing resin has been conventionally used. The above resin is a thermosetting resin used as an adhesive for foundry sand.

Mainly phenolics are used.

The core 6 described above is generally formed by thermosetting core sand 5 into a predetermined shape using a heated mold.

When removing sand from the core sand 5 after casting, the cylinder head 1 after casting is sand-baked in the state shown in FIG. 2 using an annealing furnace (not shown). Then, after a certain period of time has elapsed until most of the resin contained in the core sand 5 has finished burning, the sand firing is finished.

This sand firing is also performed as annealing of the cylinder head 1, but the time required for annealing can be completed in a very short time compared to the time required for sand firing.

After the sand firing is completed, the cylinder head 1 is taken out of the annealing furnace and the core sand 5 decomposed by burning the resin is removed from the opening 3.4.

In the conventional method for removing sand from the core sand 5 described above, it takes a long time for the resin to burn when sand baking is performed in an annealing furnace. In other words, since the opening 3.4 is the only part of the cylinder head 1 where the core sand 5 comes into contact with the outside air, the opening 3.4 is the only part of the cylinder head 1 that is exposed to the outside air. The combustion had to be carried out sequentially from around parts 3 and 4, which took a long time.

(Problems to be Solved by the Invention) As explained above, the conventional method for removing sand from core sand does not allow enough oxygen to penetrate into the core to burn the resin when sand baking is performed in an annealing furnace. This method required a long time to burn, starting from the opening of the casting, and was not a highly productive method.

This invention was made in view of the above circumstances.

The purpose of this invention is to reduce the time required for subsequent sand baking and improve the productivity of the casting by removing sand from the core sand near the opening that opens to the outside of the casting immediately after casting.

[Structure of the invention]

(Means and effects for solving the problem) This invention has the following features:
At high temperature immediately after casting, the core sand near the opening is supplied with air that burns the resin into the core sand from the opening that opens to the outside of the casting, and a grid that impacts and crushes the core. The first means for removing sand reduces the time required for the second means of sand baking, which is carried out thereafter, and the method for removing sand from core sand can be completed in a shorter time than conventional methods.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. 1, but the materials and structure of the cylinder head 1 as a casting and the core sand 5 are those shown in FIG. 2 as a conventional example. Since it is the same as that shown in FIG.

Immediately after casting the above cylinder head 1, the temperature is high (approximately 450℃)
°C or higher), the openings 3 and 4 of this cylinder head 1
Air 9 for burning the resin and a grid 10 for applying an impact force to the core sand 5 to crush it are supplied. That is, immediately after the resin contained in the core sand 5 is cast, air 9 containing oxygen is supplied by the plast gun 7.8 at a high temperature, thereby burning the resin in the core sand 5 and forming it as an adhesive. The function can be removed and the core 6 can be disassembled. At this time, the plastic gun 7.8 is operated so as to gradually approach the cylinder head 1 to enhance the effect of decomposing the core sand 5.

Furthermore, the core 6 can be crushed by causing the grid 10 to collide with the core 6 using the blast force of the air 9 from the blast gun 7.8.

Here, since the grid 10 is a piece of steel grain with sharp edges, the core 6 formed by the bonding of the core sand 5 is sequentially crushed inward from the opening 3° 4 by the collision of the grid 10. Then, a cavity 11 is formed.

By the first means as described above, the core sand 5 near the openings 3 and 4 is removed as shown in FIG.

Then, by the second means, the cylinder head 1 in the state shown in FIG. Burn the core sand 5. At this time, in the core sand 5, the vicinity of the opening 3.4 has already been removed to form a cavity 11, so the existence of this cavity 11 facilitates the entry of oxygen into the interior of the resin. It can promote combustion.

By implementing the sand removal method for the core sand 5 described above, the sand removal work can be completed in an extremely short time compared to the conventional method, and the productivity of the cylinder head 1 as a casting can be significantly improved. .

It should be noted that this invention is not limited to the examples described above. For example, the casting to be carried out is not limited to a cylinder head, but may be any casting that uses a core containing resin. Further, the method of supplying the air and the grid is not limited to the above, but any method may be used as long as it can obtain the same effect as the above-mentioned embodiment at a high temperature immediately after casting when the resin can be combustible.

〔Effect of the invention〕

As described above, according to the first means of the present invention, the core sand in the vicinity of the opening is removed from the opening opening to the outside of the casting when the casting is at a high temperature immediately after casting, thereby preventing the subsequent sanding. The time required for sand baking in an annealing furnace, which is the second method, is significantly shortened, and sand removal from the core can be completed in a shorter time than in the past.

In addition, by shortening the time required for sand firing,
The productivity of the second casting can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of the first means of the present invention, and FIG. 2 is a side sectional view of a conventional casting immediately after casting. 1... Cylinder head (casting), 5... Core sand. 6...core, 9...air, 10...grid.

Claims (1)

[Claims] In a method of removing sand from the core sand after casting a casting having a core formed of core sand containing resin, an opening that opens to the outside of the casting at a high temperature immediately after casting. A first means for removing sand from the core sand near the opening by supplying air that burns resin to the core sand and a grid that crushes the core sand by impacting it; and a first means for removing sand from the core sand near the opening. A method for removing sand from core sand, comprising: a second means for removing sand from remaining core sand.