JPH01278936A - Method for setting lost foam pattern into molding sand - Google Patents

Abstract

PURPOSE:To prevent the development of deformation at the time of packing molding sand without making larger than the necessary diameter and strength of a sprue, etc., for a lost foam pattern by expanding an air expanding body with the air supplied into the inner part thereof to support the lost foam pattern. CONSTITUTION:A cloth material 9 is set at lower side of a setting device 2 and fixed to a frame 3 and the lost foam pattern 1 is laid on the cloth material 9. Successively, an air supply pump is worked and the lost foam pattern 1 is supported to the frame 3 from both sides with expansion of the air expanding body 4 through an air supply passage 6. After that, the molding sand 8 is charged into a flask 13 under condition of charging a little quantity of the molding sand at the lower side thereof and the cloth material 9 at the lower side of the frame 3 is pulled out. After that, the molding sand 8 is packed up into the flask 13 from upper part while applying vibration to the flask 13 with a vibrating device 14. The lost foam pattern 1 is fixed with the molding sand 8 itself and then, the air expanding body 4 is shrunk with dead weight of the molding sand 8 to stop the supporting with the expanding body 4, and the frame 3 is shifted upward. At the time of completing the packing of the molding sand 8, the lost foam pattern 1 is surely fixed with the molding sand 8 and the deformation is not developed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention involves embedding a disappearing model made of polystyrene foam or the like into a desired casting shape in molding sand in a casting flask, and then pouring molten metal into it. The present invention relates to a vanishing model casting method for obtaining a casting while vanishing the vanishing model.

(Prior art) Conventionally, when obtaining irregularly shaped pipes, etc. by casting, a cylindrical disappearing model used therein is backed up with foundry sand, and molten metal is directly injected into the disappearing model to replace it to obtain a casting (for example, in JP-A-59 (Refer to Publication No.-191543). When filling with molding sand, if the vanishing model is insufficiently fixed, the vanishing model may be deformed by the load on the vanishing model caused by the movement of the molding sand, and the desired casting may not be obtained. In order to prevent this deformation, sprues, runners, weirs, etc. are made thicker and stronger, but this method has a poor casting yield and requires a lot of time for post-processes such as weir cutting. Ta.

(Objective of the Invention) The present invention has been made in view of the above-mentioned problems, and its purpose is to provide sprues, runners, weirs, etc. of vanishing models that are easily deformed when filled with molding sand, such as irregularly shaped pipes, as described above. The aim is to prevent deformation of the disappearing model when filling with foundry sand without making it thicker and stronger than necessary.

(Structure of the Invention) The structural features of the present invention for achieving the above-mentioned object 1 are as follows:
A method of charging a vanishing model into a sand mold in a vanishing model casting method in which a vanishing model is buried in molding sand in a casting flask, and then a casting is obtained while disappearing with molten metal, and the vanishing model is placed in a sand mold by air supplied inside. A process of inflating the air expansion body to support the vanishing model, a process of filling molding sand around the vanishing model supported by the air expansion body and holding the vanishing model with the molding sand, and a process of expanding the air inside the air expansion body. and a step of discharging and taking out the air expanded body from within the molding sand.

(Effects of the Invention) According to the method of putting a disappearing model into a sand mold of the present invention, the sprue, runner,
To obtain a highly accurate casting without making a weir or the like unnecessarily thick and strong, by reliably fixing a vanishing model when filling with molding sand, and preventing deformation of the vanishing model.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The vanishing model 1 is formed of a product part 1a having a desired shape, a weir 1b, a runner 1c, and a yoke 1d.
The size and shape of the spout 1d of the b N yjJ road 1c1 are determined by considering the circumference of the hot water.

In the case of this embodiment, since the disappearing model l has a curved shape, it is likely to be deformed during filling with molding sand 8.

The insertion device 2 for the vanishing model 1, which is used to fill sand around the vanishing model 1, will be explained with reference to FIGS. 1 and 2.

In the charging device 2, an air expansion body 4 is fixed to a frame 3 made of a pipe via a support plate 5. An air supply passage 6 is connected to this air expansion body 4 in order to connect it to an air supply pump (path shown in the figure) that supplies air. A switching valve 7 is provided for release to the atmosphere. A cloth material 9 for setting the disappearing model 1 is provided on the lower side of the frame 3. The cloth material 9 is for supporting the lower side of the disappearing model 1, and the end portion 9a is attached to the frame 3.
The electromagnet 10 provided in the frame 3 is fixed by magnetic force between the frame 3 and the electromagnet 10 provided therein. Also, one end 9b
is connected to a wire 12 supported by a rotary roller 11 rotatably provided at a corner of the frame 3, and by releasing the fixation of the electromagnet io and pulling the wire 12, the cloth material 9 is moved to the lower side of the frame 3. It is now possible to extract it from the

The charging device 2 is loaded into the flask 13 shown in FIG. 3 while supporting the vanishing model 1, and is vibrated around the vanishing model 1 by a vibration device 14 provided at the bottom of the flask 13. is filled with casting sand 8.

Next, this embodiment will be explained in order of steps.

The cloth material 9 on the lower side of the feeding device 2 is fixed to the frame 3 at the end 9a with an electromagnet 10. Model 1 disappears in this state
is placed on the fabric material 9, the air supply pump (shown in the figure) is operated, and the air expansion body 4 is expanded through the air supply passage 6, thereby supporting the vanishing model 1 with respect to the frame 3 from both sides.

As shown in Fig. 3, the vanishing model 1 supported on the frame 3 is put into the casting flask 13 with a little bit of molding sand 8 added to the bottom, and the electromagnet 1° is released to remove the wire. 1
2 and pull out the cloth material 9 on the frame 3F side. Thereafter, molding sand 8 is filled into the flask 13 from one side while applying vibration to the flask 13 using the vibration device 14.

As shown in FIG. 4, the molding sand 8 is filled with molding sand 8.
When it reaches the height where the vanishing model 1 is fixed,
The switching valve 7 is switched to release the air in the air expansion body 4 to the atmosphere, the air expansion body 4 is contracted by the weight of the molding sand 8, the support of the vanishing model 1 by the air expansion body 4 is stopped, and the frame 3 is move it upwards.

Next, as shown in FIG. 5, the molding sand 8 is filled up to a predetermined height to complete the filling of the molding sand 8. At this time, disappearing model 1
Since the molding sand is firmly fixed by the molding sand filled in first, no deformation occurs.

As explained above, according to this embodiment, the weir tb of the disappearing model 1 is easily deformed when filling with the foundry sand 8.

Runway 1cs To securely hold the vanishing model 1 and prevent deformation of the vanishing model 1 when filling molding sand 8 without making the sprue 1d unnecessarily thick and strong, and to efficiently obtain a casting with good rn degree. I can do it.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a side showing a disappearing model insertion device], FIG. 2 is a perspective view showing a disappearing horizontal type immersion device, and FIG. 3 is a side showing a disappearing model insertion state. FIG. 4 is an explanatory diagram showing the state of filling of molding sand, and FIG. 5 is an explanatory diagram showing the completion of filling of molding sand. 1... Disappearance horizontal type, 2... Loading device, 4
... Air expansion body, 8 ... Foundry sand, 13
...Cast flask.

Claims (1)

[Claims] A method of charging a vanishing model into a sand mold in a vanishing model casting method in which a vanishing model is buried in molding sand in a casting flask, and then a casting is obtained while disappearing with molten metal, and the vanishing model is placed in a sand mold by air supplied inside. A process of inflating the air expansion body to support the vanishing model, a process of filling molding sand around the vanishing model supported by the air expansion body and holding the vanishing model with molding sand, and a process of expanding the air inside the air expansion body. A method for introducing a vanishing model into a sand mold, comprising the step of discharging and taking out the air expanding body from the molding sand.