JPS61159244A - Core molding method - Google Patents

Abstract

PURPOSE:To reduce cleaning time and to improve the efficiency of cleaning in discharging of the core sand in a mold by air blowing after blowing a gaseous amine to cure the core sand by using the inside of ejector pins as discharge paths and feeding backward the compressed air through the pins in the stage of parting the mold thereby speeding up the discharge operation and removing the material sticking to the pins. CONSTITUTION:The gaseous amine 3 is blown into a core mold 1 to cure the core sand W packed into the mold. The air is blown into the mold through below holes 3 to discharge the sand. The hollow inside of the ejector pins 15 for parting are also used as the discharge paths in addition to an air vent 6 to suck the sand, by which the discharge time is reduced. The compressed air is fed backward into the mold through the inside of the pins 15 in the stage of parting the mold, by which the molding sand and resin sticking to th pins 15 and conduit G are removed. The time for the cleaning operation is thus reduced and the working efficiency of the core device is improved.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for molding a core using a core mold.

BACKGROUND ART An example of a method for molding a core using a cold box type core molding machine is shown in FIG. 3 (At, (13)) and FIG. 4.

As shown in the figure, wet core sand, which is a mixture of foundry sand and a liquid resin binder, is blown into the product space of a core mold 1 consisting of an upper mold 1a and a lower mold 1b. Amine gas is blown as a catalyst for accelerating curing from the blow nozzle 3 of the sing head 2, thereby instantly curing the filled core sand and molding the core W.

In this case, if the injection of amine gas is cut off at the same time as the molding is completed, amine gas will remain in the core W. Therefore, after blowing the amine gas for a predetermined period of time, compressed air is blown from the gashing head 2 instead of the amine gas (this operation is called air purge) to expel the amine gas remaining in the core W. The amine gas cooled and discharged from the core W is discharged from the air vents 6 provided at multiple locations on the core mold, in addition to the gap G between the bottle hole 4 of the lower mold 1b and the extrusion pin 5, and is then disposed of. It is collected from pipe 8.

Note that 7 is an extrusion plate to which an extrusion pin 5 is attached.

When the molding is completed, the mold is opened as shown in FIG. 3 (Bl), and the extruder 15 is moved upward by the action of the cylinder 9, so that the core W is released from the lower mold 1b.

Problems to be Solved by the Invention According to the method for discharging amine gas as described above, the opening area of the discharge passage is small and the flow resistance is large. Curing is delayed and porcelain defects such as staining are likely to occur.

Furthermore, since the opening area of the discharge passage is small, sand and resin particles tend to adhere to it and cause clogging, and the mold must be cleaned frequently.

The present invention is a core manufacturing method that solves the above-mentioned problems. This is what we are trying to provide.

Means for Solving Problem R The present invention is a method of molding a core by hardening the core sand by blowing amine gas as a hardening agent into the core sand filled in a core mold. After blowing in amine gas, compressed air is blown in instead of the amine gas to exhaust the amine gas remaining inside the core, and a hollow extrusion pin for core release is used as a discharge passage inside the core. Drain remaining amine gas.

In addition, when the core is released from the mold by the ejector pin, the ejector pin that was previously used as the discharge passage is used as an air passage.
Conversely, a method is used in which compressed air is blown out from an extrusion pin.

Function As mentioned above, since the ejector pin itself is used as a passage, not only is the circulation improved when the amine gas is discharged, but also air is blown out from the ejector pin when the ejector pin is operated, and the air pressure prevents the amine gas from adhering to the bottle. Any sand or resin particles that are present are removed.

Embodiment FIG. 1 (5) Once is a diagram showing an example of a core mold used in the method of the present invention, and the same parts as in FIG. 4 are given the same symbols.

As shown in FIG. 1 (5) and proviso, the extrusion pin 15 is formed into a hollow shape, and this hollow extrusion pin 15
A large number of slits 10, 10... are formed on the peripheral wall of the push-out pin 1 (Fig. 2), and the gap G is communicated with the inside of the push-out pin 15 through these slits 10, 10...
The inside of 5 is used as a part of a discharge passage for discharging amine gas, which will be described later.

On the other hand, an extrusion plate 17 to which an extrusion pin 15 is attached
A chamber portion 11 communicating with the extrusion pin 15 is formed in the
These chamber parts 11 are connected to the pressure source 1 via a solenoid valve 12.
Connected to 3. A plug 14, which is a stopper, is detachably attached to the bottom of the chamber portion 11.

Here, one embodiment of the method of the present invention using the above-mentioned core mold will be described.

As shown in FIG. 1 (5), after core sand is blown into the core mold 1 and filled, amine gas is blown from the blow nozzle 3 to harden and mold the core W. At this time, since the bow P of the electromagnetic valve 12 is open, the amine gas passes through the gap G between the bottle hole 4 and the push-out pin 15 and the air pent 6, and is discharged from a processing pipe (not shown). Also, push out pin 1 from gap G.
The amine gas passing through the solenoid valve 12 is discharged from a pipe (not shown) connected to the processing nozzle via the boat P of the solenoid valve 12.

Then, after blowing in the amine gas, the amine gas in the core W is discharged to the outside by blowing compressed air from the probe nozzle/l/3 in place of the amine gas.

In addition, when the amine gas passes through the inner m of the extrusion pin 15 from the gap G, the opening area is large (because of this, the flow velocity becomes small, and the sand and resin particles carried along with the amine gas are collected in the chamber W511).

These collected sand JP resin maki are regularly plugged 14
It can be removed by raising .

After the blowing of compressed air from the blow nozzle 3 is completed, the first
As shown in Figure (B), the mold is opened and the extrusion pin 15 is raised together with the extrusion plate 17, and at the same time the solenoid valve 12 is switched. As a result, the core W is separated from the lower g1b,
At the same time, compressed air is blown out from the slit 10 of the extrusion pin 15 to blow off and remove sand and resin particles adhering to the periphery of the extrusion pin 15.

Effects of the Invention As described above, according to the present invention, by utilizing the inside of the extrusion pin as a part of the discharge passage, passage of amine gas becomes easier and the curing reaction rate of the core increases. Therefore, the amount of amine gas used can be reduced, and molding defects such as staining are also reduced.

In addition, by having a self-cleaning function by blowing air from the extrusion pin, it is possible to prevent clogging, and it is also possible to improve the equipment operating rate by shortening the cleaning time due to adhesion of sand, etc.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are process explanatory diagrams showing one embodiment of the method of the present invention, Figure 2 is a perspective view of the ejector pin in Figure 1 (A), and Figure 3 (A+ and (I3)). 4 is a process explanatory diagram showing an example of a conventional core molding method, and FIG. 4 is an enlarged view of the main part of FIG.・Lower mold, 1
0... Slit, 12... Solenoid valve, 13... Pressure source, 15... Extrusion pin, 17... Extrusion plate, G
... Gap, W... Core. Ku Ward Ward C'3 ■w&
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Claims (1)

[Claims] (1) A method of molding a core by hardening the core sand by blowing amine gas into the core sand filled in the core mold, and after blowing the amine gas, the amine gas is replaced with the amine gas. When the amine gas remaining in the core is discharged outside the mold by blowing compressed air into the core, the inside of the extrusion pin for core release is used as a discharge passage to exhaust the remaining amine gas, while the inside of the extrusion pin is used as a discharge passage. A core molding method characterized by blowing out compressed air from the extrusion pin during a mold release operation.