JPH01157760A - Method for cooling and heating die - Google Patents

Abstract

PURPOSE:To extend service life without generating local thermal stress inside a die by filling a thermal transfer medium via a cover member to the outside peripheral face of a cavity, burying a piping into this thermal medium and circulating a cooling or heating fluid in this piping. CONSTITUTION:At the injection time of a molten metal into a cavity 16 a high temp. heating fluid is circulated inside circulation piping passages 24, 32 and the temp. of dies 12, 14, especially the temp. of the inner peripheral faces 16a, 16b of the cavity 16 is raised to the specified temp. The heat of the heating fluid is transferred to heat transfer mediums 22, 30 and this heat is transmitted to the cavity inner peripheral face 16 from a die outside peripheral face 18 or to the cavity inner peripheral face 16b from a die outer peripheral face 26. The molten metal casting can be filled leniently by low pressure and simultaneously with the filling completion a cooling stage comes in. In cooling the whole area is uniformly cooled through a cooling medium to the piping passages 24, 32. Due to uniform cooling or heating being able to be executed from the whole area of the cavity inner and outer peripheral faces no local thermal stress is generated on the die and the leakage accident of cooling water can be eliminated as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cooling and heating a mold used in die casting and the like.

[Conventional technology]

Generally, in die casting, etc., in order to efficiently produce healthy products, the mold is heated to a predetermined temperature when molten metal is poured, and then cooled after casting to solidify the molten metal in a short time. be done.

Conventionally, cooling or heating of such molds has been carried out by circulating cooling water through cooling water passages machined inside the mold, while cooling has been carried out by circulating cooling water through cooling water passages machined inside the mold. This was done by energizing an electric heater buried inside the mold.

[Problem that the invention seeks to solve]

However, in the conventional cooling and heating methods as described above, since the cooling water passage and the electric heater are drilled or buried inside the mold, they basically have the following drawbacks.

First of all, since the heater or cooling water passage is installed partially inside the mold and with the gold in direct contact with the base metal, the gold is heated locally and irregularly within the base metal. The life of the mold is shortened due to the stress generated. Second, cracks are likely to occur in the cooling water passages due to thermal stress, especially due to high temperature heaters, which induces leakage of cooling water. In this case, it is also possible to configure heating by circulating hot water in the cooling water passage without using a heater, but if configured in this way, the above-mentioned cracks and the circulating water Although the occurrence of leakage can be suppressed, on the other hand, the temperature of the mold during heating is only raised to the level of residual heat, which lengthens the casting cycle and makes it impossible to obtain a sound cast product. Thirdly, as mentioned above, since the cooling water passage and the electric heater are provided inside the mold, the entire mold becomes large and heavy, which increases the heat capacity a and increases the amount of heat and time required for cooling and heating. is increased.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a metal mold that can quickly and evenly raise and lower the temperature of a mold to a required cooling temperature and heating temperature, and that can be configured to be relatively small, lightweight, and highly durable. The purpose of the present invention is to provide a method for cooling and heating a mold.

[Means for solving problems]

In order to achieve the above object, cooling of the mold according to the present invention,
The heating method involves filling the outer peripheral surface of a cavity in a mold with a heat transfer medium through a cover member, embedding a circulation piping path in the heat transfer medium, and inserting a cooling and/or heating fluid into the circulation piping path. It is characterized by circulating.

In this case, it is preferable to use a high boiling point fluid as the cooling and/or heating fluid.

[Effect]

The mold is uniformly cooled or heated from the entire inner peripheral surface of the cavity in the mold through a heat transfer medium that is cooled or heated to a uniform temperature by the fluid that is circulated in the circulation piping. . Therefore, local thermal stress is not generated within the mold, and the mold base material is prevented from cracking due to thermal fatigue. Furthermore, as mentioned above, local stress is not generated inside the mold, and the cooling or heating means is provided outside the mold, so the mold can be configured to be small and lightweight. be able to. At the same time, a high boiling point fluid is used as the cooling or heating fluid, and its temperature can be set to the required low or high temperature, so the mold can be quickly cooled or heated to the required temperature. Can be done.

〔Example〕

Next, a method for cooling and heating a mold according to the present invention will be described in detail below with reference to the accompanying drawings showing an embodiment of a mold configured to carry out the method.

In the figure, a mold 1 for carrying out the cooling and heating method of the present invention.
0 consists of a movable mold 12 and a fixed mold 14, with a cavity 16 formed between them. The outer circumferential surface 18 of the cavity 16 that forms the inner surface of the movable mold 12 is filled with a heat transfer medium 22 via a cover member 20 so as to cover the entire outer circumferential surface 18. A circulation piping path 24 for cooling and heating fluids made of high boiling point fluid is buried inside. On the other hand, the outer circumferential surface 26 of the cavity 16 that forms the outer surface of the fixed mold 14 is filled with a heat transfer medium 30 via a cover member 28 so as to cover the entire outer circumferential surface 26. Embedded in the medium 30 is a cooling and heating fluid circulation piping 32 also made of a high boiling point fluid. The molds 12 and 14 of the present invention configured in this manner have a simple structure, as is clear from the drawings, because no fluid circulation path or heating means are drilled or buried inside the molds 12 and 14. , the size is smaller and the weight is also reduced. Note that as the high boiling point solution, for example, polywater or the like can be used. Also,
The attachment of the cover member 20.28 to the outer circumferential surface 18.26 of the respective mold 12.14 can be achieved, for example, by
It can be attached as appropriate via a 7-run 9 section (not shown) provided on the periphery of the 0.28 mm.

In such a configuration, when injecting molten metal into the cavity 16, a high-temperature heating fluid is circulated in the circulation piping 24.32 in advance to control the temperature of the molds 12, 14, especially the inner circumferential surface 16a of the cavity 16. , 1'6b to a predetermined temperature. During this mold heating, the heat from the circulating heating fluid is once transferred to the heat transfer medium 22, 30, respectively.
The heat of the heat transfer medium 22.degree. 30 is transferred from the mold outer circumferential surface 18 to the cavity inner circumferential surface 16a or from the mold outer circumferential surface 26 to the cavity inner circumferential surface 16b, respectively.

In this way, the molds 12 and 14 extend from the entire outer circumferential surface 18.26 of the cavity 16 to the inner circumferential surface 16a of the cavity 16.
, 16b, the temperature inside the mold is increased with a uniform temperature gradient. Therefore, no local thermal stress is generated inside the molds 12, 14. Moreover, since the heating fluid is set at a sufficiently high temperature and the molds 12.degree. 14 are relatively light, the temperature of the molds 12.degree. 14 is quickly raised. In this way, the temperature of the cavity inner circumferential surfaces 16a, 16b is uniformly and rapidly raised over the entire circumferential surface. Therefore, when pouring the molten metal in the next step, the molten metal can be filled gently at low pressure without involving gas, and at the same time as the filling is completed, the next cooling step can be started. Therefore, it is possible to produce a cast product that is sound and has high strength without causing cavities.

Next, in the cooling step, instead of the heating fluid, a low-temperature cooling fluid is circulated into the circulation piping 24.32 to cool the mold 12.14. During this mold cooling, the circulating cooling fluid once cools the respective heat transfer mediums 22 and 30. The heat of the molten metal within the cavity 16 is transferred to the inner peripheral surface 16a of the cavity 16.

16b through the molds 12.14, respectively. ．． Along with the heat inside the mold 14, the mold outer peripheral surface 18,
26. In this way, the molten metal and the molds 12 and 14 in the cavity 16 are
a.

16b to the outer peripheral surface 18.26 of the mold 12.14.
Since the entire area of the molten metal is cooled uniformly, the temperature inside the molten metal and the molds 12 and 14 is lowered with a uniform temperature gradient.

Moreover, since the cooling fluid is set at a predetermined low temperature and the mold 12.14 is relatively light, the molten metal is quickly cooled and solidified to form a high-strength cast product, and the mold 12. .14, no local thermal stress is generated inside it.

As explained above, according to the mold cooling and heating method of the present invention, the mold is heated from the entire inner and outer peripheral surfaces of the cavity in the mold through a heat transfer medium that is set at a uniform temperature. Uniformly cooled or heated. Therefore, local thermal stress is not generated within the mold, and the life of the mold is extended. In addition, since the mold does not require cooling or heating means inside its base material, the structure is simple, compact, and lightweight, and the temperature of the cooling or heating fluid can be freely set to the required low or high temperature. Therefore, heating of the mold or cooling of the mold and molten metal to be cast can be performed quickly.

Therefore, the casting cycle can be shortened, and at the same time, a cast product that is sound and has high strength can be manufactured.

The cooling and heating methods of the present invention have been described above with reference to preferred embodiments of molds for carrying out the methods, but it goes without saying that the present invention can be modified in many ways without departing from its spirit. .

〔Effect of the invention〕

As explained above, the method for cooling and heating a mold according to the present invention involves filling the outer peripheral surface of a cavity in the mold with a heat transfer medium via a cover member, and embedding a circulation piping path in the heat medium. However, since the cooling and heating fluid is circulated within the circulation piping, the mold can be uniformly cooled or heated from the entire inner and outer peripheral surfaces of the cavity. Therefore, local thermal stress is not generated within the mold, and the life of the mold can be extended. In particular, leakage accidents of cooling water, etc., which often occur in conventional molds, can be eliminated. Also,
Since the mold does not require any cooling or heating means inside its base material, the structure is simple, compact and lightweight, and the cooling or heating temperature can be freely set to the required temperature. It is possible to quickly heat the mold or cool the mold and molten metal. Therefore, the casting cycle can be shortened, and at the same time, a cast product that is sound and has high strength can be manufactured.

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of a mold for carrying out the mold cooling and heating method according to the present invention. 10... Mold 12... Movable mold 14.
...Fixed mold 16...Cavity 16a,
16b...Cavity inner circumferential surface 18, 26...Cavity outer circumferential surface 20, 28...Cover member in the mold 22.30...Heat transfer medium 24, 32...Circulation piping path

Claims (2)

[Claims] (1) Fill the outer peripheral surface of the cavity in the mold with a heat transfer medium via a cover member, embed a circulation piping path in the heat transfer medium, and supply cooling and/or heating fluid into the circulation piping path. A mold cooling and heating method characterized by circulation. (2) A method for cooling and heating a mold according to claim 1, wherein the cooling and/or heating fluid is a high boiling point fluid.