JP2003103343A - Emergency repair method for casting mold or core forming mold using inorganic material sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple emergency repair method for repairing a mold in a short time and easily without releasing the mold from a device when a casting mold or core forming mold composed of a pair of molds is used many times repeatedly, and a strain is generated on the clad face of a pair of the molds causing a clearance. SOLUTION: When the casting mold or core forming mold composed of the pair of molds is used many times repeatedly, and the strain is generated on the clad face of the pair of the molds causing the clearance, a heat resistant adhesive is interposed on the clad face of either one mold without releasing the mold from the device to stick a heat resistant nonorganic material, then the clad face is pressed by attaching the other mold to seal the clearance on the clad face with the heat resistant inorganic material. After holding the molds for a predetermined time, the forging operation or the core forming operation can be resumed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an emergency repairing method using an inorganic material sheet of a casting mold or a core molding mold.

[0002]

2. Description of the Related Art When a molten metal or the like is filled in a mold cavity by using a mold such as a mold casting method, a semi-melt molding method, a semi-solid molding method and a die casting method, or by using a mold. When molding the core, if the mold is repeatedly used many times, the mold will undergo a number of pressure cycles due to the mold clamping force and thermal cycles of temperature increase / decrease. The mold mating surface is distorted and a gap is created on the mating surface. In particular, in the case of a vertically long mold, when there is a large difference in shape and size between the upper mold and the lower mold, distortion is likely to occur due to the difference in expansion and contraction, and a gap is likely to occur on the mating surface of the mold.

If the gap between the mating surfaces of these molds becomes large, for example, in the case of die casting, the molten metal is press-fitted into the mold at high pressure during casting, which causes blowing from the gap and causes a work site. As dangerous. Further, the cast product also causes defective products or burr due to defective filling of the molten metal. Even in the GD casting, even if the problem of blowing is small, the problem of non-molding due to the occurrence of burrs and non-circulation of the molten metal occurs.

Further, when molding a core using a mold, sand and air blown into the cavity of the heated mold are ejected from the gaps between the molds, and the sand and air are blown to each location in the branched cavity. The sand is not uniformly distributed, and as a result, a shell in which the entire surface is uniformly and densely packed cannot be formed, which causes a problem that a defective core having a thin portion, a hollow portion or a portion having insufficient strength is formed.

Therefore, conventionally, when such a gap is formed in the mating portion between the molds, the mold is removed from the apparatus (casting machine or molding machine), and the gap is subjected to build-up welding or polishing. It was attached to the device after being repaired by machining. The mold is generally large in size, and it takes a considerable amount of labor and time to remove or mount it from the device, and usually requires a repair period of 2 days to 1 week. It becomes a serious problem when many repair days cannot be taken due to the delivery time.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to provide a casting mold or a core mold for forming a pair of molds. When the mold is repeatedly used many times and distortion occurs in the mating surfaces of the pair of molds and a gap is created, it is easy to repair the gap in a short time without removing the mold from the device. It is to provide an emergency repair method.

[0007]

According to the present invention, a casting mold or a core molding mold composed of a pair of molds is repeatedly used many times, and strain is applied to the mating surfaces of the pair of molds. When a gap is generated, without removing the mold from the device,
After sticking a heat-resistant inorganic material sheet with a heat-resistant adhesive interposed on the mating surface of one of the molds, the other mold is pressed together and the heat-resistant inorganic material sheet is used to press the mating surface. An emergency using an inorganic material sheet of a casting mold or a core molding mold, which is capable of resuming the casting work or the core molding work after sealing the gap and maintaining it for a predetermined time. Repair methods are provided.

In the present invention, the inorganic material sheet is preferably a graphite tape.

Further, in the present invention, it is preferable that the mold temperature when the inorganic material sheet is attached is 300 ° C. or lower.

[0010]

Embodiments of the present invention will be described below, but it goes without saying that the present invention is not limited to the following embodiments. When a casting mold or a core molding mold composed of a pair of molds is repeatedly used a number of times, distortion occurs in the mating surfaces of the pair of molds, and when a gap is created, an emergency repair of the present invention is performed. The method is to stick a heat-resistant inorganic material sheet to the mating surface of one of the molds with a heat-resistant adhesive interposed, and then press the other mold together without removing the mold from the device. However, the gap between the mating surfaces is sealed with a heat-resistant inorganic material sheet, and then held for a predetermined period of time so that the casting operation or the core molding operation can be restarted.

For example, in the case of die casting of an aluminum alloy, by repeatedly casting a large number of times, a gap is likely to be formed around the gas vent valve provided on the upper mating surfaces of the pair of dies that open and close to the left and right. When the size of the gap is such that blowing occurs, casting is stopped and the width of about 10 mm cut according to the mold surface of the part where one mold opened to the left and right blows Apply a heat-resistant adhesive to the graphite tape and attach it to the die surface. It is desirable that the thickness of the tape be appropriately selected according to the degree of the gap. Usually, a graphite tape having a thickness of about 0.5 mm is often used. Depending on the extent of the gap, a thicker graphite tape is used. Alternatively, a plurality of graphite tapes may be stacked and used.

Apply a heat-resistant adhesive to the graphite tape,
The temperature of the mold when it is attached to the mold surface is in the high temperature state around 200 ° C. Of course, if there is enough time to repair, cool the die surface, apply a heat-resistant adhesive to the graphite tape at a lower temperature, and paste it on the die to restart casting later. It is desirable because the number of shots increases. The graphite tape is coated with an adhesive and attached to one mold, and then the other mold is aligned and pressed. The attached graphite tape is crushed, spread, fills the gap between the molds, and seals.
Hold in this state for 15 minutes.

After 15 minutes, even if the other mold is opened, the graphite tape sealing surface does not adhere to the other mold surface. It is firmly bonded to one mold via an adhesive. Casting was resumed using the thus repaired mold, and a durability of 80 shots was obtained.

Inorganic material sheets other than graphite tape are also possible. Various selections can be made depending on the conditions such as casting material and casting temperature. As the inorganic material sheet, an inorganic material sheet can be produced by a paper-skipping method from a mixed liquid obtained by adding a binder and organic fibers or / and inorganic fibers to an inorganic material powder such as graphite or alumina. 50 for shell core molding
The mold temperature is heated to around 0 ° C, but if the mold temperature during repair is higher than 300 ° C, the effect of the adhesive decreases, so
It is preferable to repair the mold surface at 300 ° C. or lower.

[0015]

As described above, according to the emergency repair method using the inorganic material sheet of the casting mold or the core molding mold of the present invention, a pair of molds are repeatedly used. When a distortion is generated on the mating surface of and the gap is generated, the gap can be easily repaired in a short time without removing the mold from the apparatus. Moreover, the repaired mold has sufficient durability.

Claims (3)

[Claims] 1. When a casting mold or a core molding mold comprising a pair of molds is repeatedly used many times, and when a pair of molds are distorted to form a gap on the mating surfaces, Without separating the mold from the apparatus, a heat-resistant inorganic material sheet is attached to the mating surface of one of the molds with a heat-resistant adhesive interposed, and then the other mold is pressed together. A mold for casting or a core molding, characterized in that the space between the mating surfaces is sealed with a heat-resistant inorganic material sheet, and after holding for a predetermined time, the casting work or the core molding work can be restarted. Emergency repair method using the inorganic material sheet of the mold. 2. The emergency repair method using the inorganic material sheet of the casting mold or the core molding mold according to claim 1, wherein the inorganic material sheet is a graphite tape. 3. The inorganic material sheet for a casting mold or core molding mold according to claim 1, wherein the mold temperature when the inorganic material sheet is attached is 300 ° C. or lower. Emergency repair method using.