JP2005329439A - Molding method for mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problem that the filling of molding sand becomes defective state in the case of changing the height of a squeeze head for the purpose of preventing the projection or the recession of the upper surface of a mold from the upper surface of a molding flask with the difference in the squeeze length of molding sand based on the change of CB value, in the molding method squeezing the molding sand by shifting a squeeze means to a pattern plate side after blowing the molding sand with a sand-blowing device for spouting the molding sand by supplying compressed air onto the upper surface of the molding sand while floating the molding sand near a sand spouting hole by spouting the compressed air into a molding chamber demarcated with the pattern plate, the molding flask and the squeeze means. <P>SOLUTION: This molding method for mold is performed as follows, in which a shifting distance to the pattern plate side of the squeeze means at the completing time of squeezing the molding sand in the molding chamber is measured and the difference between this measured value and a target value is calculated and based on this calculated result, the spouting time of the compressed air near the molding sand spouting hole is shortened or lengthened to change the filling state of the molding sand into the molding chamber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a mold making method.

Conventionally, as one of the mold making methods, a molding chamber is formed by a casting frame placed on a model plate, a filling frame in contact with the casting frame, and a split squeeze head inserted into the filling frame from above. After the compressed air is blown to the foundry sand near the sand outlet of the sand blowing device to float the foundry sand, the compressed air is supplied to the upper surface of the foundry sand for a predetermined time from the sand blowing device. There is one in which casting sand is blown and filled into the molding chamber, and the squeeze head is lowered to squeeze the casting sand so that the upper surface of the mold is at the same level as that of the casting frame.

However, in the conventional mold making method configured as described above, the length of squeeze of the foundry sand differs depending on the change in the CB value (compactability), which is the property of the foundry sand. There was a problem of protruding from the upper surface of the frame or being lowered.
Therefore, in order to solve this problem, the height of the squeeze head is changed to change the volume of the molding chamber. If the changed volume is too large, supply of compressed air to the upper surface of the foundry sand is performed. Sand filling time is insufficient and sand filling becomes poor.
JP 2002-346697 A

The problem to be solved is that if the height of the squeeze head is changed in order to prevent the upper surface of the mold from protruding or lowering from the upper surface of the casting frame due to the difference in the squeeze length of the foundry sand based on the change in the CB value. This is the point that the sand filling becomes poor.

In order to solve the above-mentioned problems, the mold making method of the present invention is a method in which a molding air defined by a model plate, a casting frame, and squeeze means is blown while jetted air is blown to float casting sand near a sand outlet. In the mold making method of squeezing the foundry sand by blowing the foundry sand by a sand blowing device for ejecting the foundry sand by supplying compressed air to the upper surface of the sand, then moving the squeeze means to the model plate side, When the squeeze of the foundry sand in the molding chamber is completed, the distance traveled to the model plate side of the squeeze means is calculated and the difference from the target value is calculated. The filling time of the molding sand into the molding chamber is changed by shortening or lengthening the jetting time of the compressed air.

As is apparent from the above description, the mold molding method of the present invention is a method in which the molding air defined by the model plate, the casting frame and the squeeze means is blown while the molding sand near the sand outlet is floated by jetting compressed air. In the mold making method of squeezing the foundry sand by blowing the foundry sand by a sand blowing device for ejecting the foundry sand by supplying compressed air to the upper surface of the sand, then moving the squeeze means to the model plate side, When the squeeze of the foundry sand in the molding chamber is completed, the distance traveled to the model plate side of the squeeze means is calculated and the difference from the target value is calculated. Since the injection time of the compressed air is shortened or lengthened to change the filling state of the foundry sand into the molding chamber, the squeeze length of the foundry sand corresponds to the change in the CB value (compactability). The molding chamber is filled with foundry sand to prevent the upper surface of the molded mold from protruding or lowering from the upper surface of the casting frame even if the CB value (compactability) changes. Excellent practical effects such as being able to

The best mode of a mold making apparatus to which the present invention is applied will be described in detail with reference to FIG. As shown in the drawing, the mold making machine can move up and down above the model plate 2 mounted on the platen-shaped conveying member 1, the cast frame 3 placed on the model plate 2, and the cast frame 3. A sand frame 5 disposed on the upper side of the casting frame 3, and a sand blowing device 5 having a lower portion slidably fitted to the bank 4, and the sand blowing device. 5 and a plurality of squeeze feet 7 and 7 mounted to be movable up and down by an air cylinder 6.

Two conveying members 1 are provided so that they can enter and exit directly below the filling frame 4 via horizontal rotating arms 8 and 8, and an extension operation of a positioning cylinder 9 mounted on a machine base 14 to be described later. As a result, the piston rod of the positioning cylinder 9 enters the recess of the conveying member 1 and is positioned. Further, a frame-like die-cut frame 10 that is mounted on the model plate 2 so as to be slidable in the up-and-down direction is mounted on each of the conveying members 1 and 1 so as to be lifted. These are raised by the extension operation of the upward cylinders 11 and 11 mounted on the machine base 14 described later.

Further, the casting frame 3 is configured to enter and exit directly above the model plate 2 through a roller conveyor 12 with a collar, and to move up and down through the roller conveyor 12 with a collar. The conveyor 12 is suspended from the lower surface of the lifting frame 13. The elevating frame 13 is constructed between the upper ends of the piston rods of two upward cylinders 15, 15 erected on the left and right of the machine base 14, and is moved up and down by the expansion and contraction operation of the cylinders 15, 15. Yes. The hydraulic circuit 19 of the cylinders 15 and 15 is equipped with a pressure sensor 20 as a detecting means for detecting a reaction force to the squeeze foot 7, and the force applied to the squeeze foot 7 is larger than a set value. Accordingly, the air cylinders 6 and 6 that are operating to expand are contracted by a signal from the pressure sensor 20.

Further, the filling frame 4 is disposed so as to be movable up and down via a plurality of cylinders 16 and 16 mounted on the left and right outer surfaces of the sand blowing device 5 and is not shown in the drawing frame 4. Vent holes 17 and 17 leading to the exhaust control chamber are formed. The sand blowing device 5 is attached to the elevating frame 13 so as to penetrate vertically, and the lower part is bifurcated, and two sand outlets 18 and 18 are provided on the left and right. .

In addition, as shown in FIG. 2, the sand blowing device 5 is provided with compressed air jetting means 21 for jetting compressed air and floating cast sand near the sand jetting port in the vicinity of the sand jetting port. .

Next, the operation of the above configuration will be described. The positioning cylinder 9 is extended to position the conveying member 1 on the machine base 14, the upward cylinders 11 and 11 are extended to raise the die frame 10, and the cylinders 15 and 15 are contracted to release the die frame. The cast frame 3 is placed on 10, the cylinders 15, 15 are extended to operate the abutment frame 4 on the cast frame 3, the central air cylinder 6 is extended to operate the squeeze foot 7, Thus, the model plate 2, the die frame 10, the casting frame 3, the filling frame 4, the sand blowing device 5, and the plurality of squeeze feet 7, 7 define a molding chamber, and the plurality of squeeze feet. 7 and 7 are arranged at a required distance from the model portion of the model plate 2. That is, when a plurality of intervals formed between the squeeze feet 7 and 7 before compression of the molding sand and the model part of the model plate 2 facing each other are A and B, and a and b after the compression are a and b, respectively. These ratios a / A and b / B are set so as to be approximately a / A = b / B.

Next, compressed air is blown from the air blowing means of the sand blowing device 5 to float the foundry sand in the vicinity of the sand ejection port, and compressed air is also supplied to the upper surface of the foundry sand to form from the sand blowing device 5. The foundry sand is blown and filled into the chamber, and then the cylinders 15 and 15 are contracted to lower the sand blowing device 5 and the squeeze feet 7 and 7 to pre-compress the foundry sand in the molding chamber. Next, the air cylinders 6 and 6 are contracted to raise the squeeze feet 7 and 7, and then the cylinders 15 and 15 are further contracted to lower the sand blowing device 5 and the squeeze feet 7 and 7 etc. Squeeze the compacted foundry sand.

Then, the descent distance of the squeeze feet 7 and 7 when the squeeze of the foundry sand in the molding chamber is completed is measured by an appropriate conventional means (not shown), and the difference from the target value is calculated. Based on the calculation result, the sand blowing device The injection time of the compressed air to the molding sand near the sand outlet in 5 is shortened or lengthened, and the filling state of the molding sand into the molding chamber is changed.
Thus, in the subsequent mold making, the foundry sand is filled into the molding chamber using the principle that the squeeze length of the foundry sand is different in accordance with the change in the CB value (compactability).

After that, the cylinders 15 and 15 are extended to release the casting frame 3 and the like, and the cylinders 16 and 16 are extended to return the filling frame 4 to the original position. The casting frame 3 with a built-in mold is carried out through 12 and an empty casting frame 3 is carried in to complete one cycle.

In the above-mentioned best mode, the molding chamber has the model plate 2, the casting frame 3 placed on the model plate 2, the filling frame 4 in contact with the casting frame 3, and the filling frame 4 from above. The squeeze means 7 and 7 are divided into the squeeze feet 7 and 7 as the inserted squeeze means. However, the present invention is not limited thereto. For example, a match plate and upper and lower casting frames sandwiching the match plate, The upper and lower squeeze plates may be defined by upper and lower squeeze plates as squeeze means inserted in the respective openings without the match plate in the upper and lower casting frames.

It is a partial cross section front view which shows the best form of the mold making apparatus to which this invention is applied. FIG. 2 is an enlarged detail view of a required part in FIG. 1.

Explanation of symbols

2 Model plate 3 Casting frame 4 Filling frame 7 Squeeze foot 21 Compressed air ejection means

Claims (3)

A sandblaster that blows out molding sand by supplying compressed air to the upper surface of the molding sand while jetting compressed air to float the molding sand in the vicinity of the sand ejection port into the molding chamber defined by the model plate, casting frame and squeeze means In the mold making method of squeezing the foundry sand by blowing the foundry sand with a squeezing device and then moving the squeeze means to the model plate side,
When the squeeze of the foundry sand in the molding chamber is completed, the movement distance of the squeeze means to the model plate side is measured and the difference from the target value is calculated. A mold molding method characterized by changing the filling state of the foundry sand into the molding chamber by shortening or lengthening the jetting time of the compressed air. In the mold making method according to claim 1,
The molding chamber includes a model plate, a cast frame placed on the model plate, a fill frame in contact with the cast frame, and a split squeeze head as the squeeze means inserted into the fill frame from above. A mold making method characterized by being defined by In the mold making method according to claim 1,
The molding chamber includes a match plate, upper and lower casting frames sandwiching the match plate, and upper openings as the squeeze means respectively inserted into openings of the upper and lower casting frames without the match plate. A mold making method characterized by being defined with a lower squeeze plate.