JP2762563B2 - Mold and its manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a die used in a die casting method or a resin molding method and a method of manufacturing the same, and more particularly, to a die having a cooling hole for cooling a die. The present invention relates to a structure of a mold and a manufacturing method thereof.

2. Description of the Related Art For example, in a low-pressure casting method, which is one of die casting methods, a mold is cooled to promote solidification of a molten metal filled in the mold and shorten cycle time. .

For example, as shown in FIG. 4, straight cooling holes 33 and 34 are formed through the lower die 31 and the upper die 32, and the cooling holes 3 and 34 are formed.
By passing a cooling medium such as compressed air through
Then, the upper mold 32 is cooled. 35 is cooling hole 3
Nipple connected to both ends of 3, 34, hose 36, W is a product.

Problems to be Solved by the Invention In such a mold structure, after sufficiently considering casting conditions and the like, a position where the entire product W is cooled as uniformly as possible is machined into the cooling holes 33 and 34. However, since the solidification rate itself is slightly different depending on the position, wall thickness, etc. of each part of the product, it is extremely difficult to cool each part of the product W under appropriate cooling conditions. There is a limit.

In addition, even if each part of the product W can be cooled under appropriate conditions at the beginning, the cooling conditions must be reviewed at the stage where the casting is performed several times and the finished state of the product is actually checked. There is. In example FIG. 4, also the cooling effect in the upper surface P ₁ of the product W is sufficient enough, that the lower surface of the product W P ₂ become supercooling that would impair the product quality can occur Often.

Then, when it becomes necessary to review the cooling conditions as described above, if the change in other cooling conditions such as the supply amount of the cooling medium cannot be dealt with, the positions of the cooling holes 33 and 34 must be changed, As a result, the mold itself needs to be remade, which is disadvantageous in terms of cost and time.

The present invention has been made in view of the above-described problems, and has as its object to cool each part of a product under appropriate cooling conditions, and furthermore, to cool the cooling hole side. An object of the present invention is to provide a mold and a method of manufacturing the mold that can flexibly cope with a change in conditions.

Means for Solving the Problems A first invention includes a cooling hole through which a cooling medium flows,
In a mold that fills a molten material into a mold and cools and solidifies to form a predetermined product, the pipe insertion hole formed through the mold is made of a metal material with good thermal conductivity and cooled. It is characterized in that a pipe having a hole is detachably inserted, and a cutout is locally formed on the outer peripheral surface of the pipe at a position corresponding to a specific portion of the product.

Further, a second invention provides a mold manufacturing method for forming a predetermined product by providing a cooling hole through which a cooling medium flows, filling a mold with a molten material and cooling and solidifying the material. A step of removably inserting a pipe made of a metal material having good thermal conductivity and having a cooling hole into the pipe insertion hole formed therethrough, and performing molding while allowing a cooling medium to flow through the cooling hole; Forming a notch locally at a position corresponding to a specific portion of the product on the outer peripheral surface of the pipe according to the finished state of the product.

According to the above-described mold structure, a difference in cooling effect can be provided between a portion where a notch is formed in a pipe and a portion where the notch is not formed, so that cooling is performed under appropriate cooling conditions according to each part of a product. become able to.

Further, according to the above-described mold manufacturing method, the molding is performed while flowing the cooling medium through the cooling hole of the pipe. As a result, for example, the upper and lower surfaces P ₁ and P _{2 of} the product W shown in FIG. In this case, the pipes 5 and 6 are once removed, and the portions corresponding to the upper and lower surfaces P ₁ and P ₂ are locally cut away to reduce the thickness, so that the space between the mold and the pipes 5 and 6 is reduced. Form R. As a result, since the space R functions as a heat insulating layer, the cooling effect on the upper and lower surfaces P ₁ and P ₂ of the product W becomes slow, and the super cooling on the upper and lower surfaces P ₁ and P ₂ can be prevented. Each part can be cooled under appropriate cooling conditions.

Embodiment FIG. 1 is a view showing one embodiment of the present invention, and shows an example of a mold for low pressure casting as in FIG.

In FIG. 1, reference numeral 1 denotes a lower die, and 2 denotes an upper die, and a product part space (cavity) is formed by the molding surfaces 1a and 2a by matching the two.

The lower die 1 and the upper die 2 are respectively formed with straight pipe insertion holes 3 and 4 penetrating in the horizontal direction. Each of the pipe insertion holes 3 and 4 has, for example, a copper pipe 5 having excellent heat conductivity. , 6 are removably inserted. The pipes 5, 6 are provided with cooling holes 5a, 6a and connected to a hose 8 via nipples 7 connected to both ends of the pipe insertion holes 3, 4, whereby the cooling water whose temperature has been adjusted is cooled by the cooling holes 5a, 6a. Through. As shown in FIGS. 2 and 3, pipes 5 and 6 have portions corresponding to specific portions of the product W, for example, portions corresponding to upper and lower surfaces P ₁ and P ₂ of the product. A part of the wall surface is locally cut away to form a notch 9.

Here, the notch 9 is formed by the following procedure.

First, pipes 5 and 6 in which notch 9 is not formed are placed first.
As shown in the figure, insert into the pipe insertion holes 3 and 4 and allow the cooling water to flow through the cooling holes 5a and 6a of the pipes 5 and 6 once or twice by a usual method under predetermined casting conditions. Perform casting.

Then, the finished state of the cast product W checked visually, for example but sufficient cooling effect for the vertical wall portion P ₃ of the product W is observed, slightly subcooled Pounds for the upper and lower surfaces P _1, P ₂ If it is recognized that the pipe 5,
6 is temporarily removed from the pipe insertion holes 3 and 4, and the pipe wall corresponding to the upper and lower surfaces P ₁ and P ₂ of the product W is locally cut away to reduce the thickness as shown in FIG. The part 9 is formed.

Next, the pipes 5 and 6 in which the cutouts 9 are formed are inserted into the pipe insertion holes 3 and 4 again, and casting is performed again while flowing cooling water. As a result, since the space R of the notch 9 functions as a heat insulating layer, the cooling effect on the product W is slower in the portion where the notch 9 is formed than in the portion where the notch 9 is not formed. As a result, each part of the product W can be cooled under appropriate cooling conditions, and the above-mentioned overcooling can be prevented.

If the cooling condition is still not appropriate after forming the notch 9, the notch 10 is additionally processed at a position shifted in phase from the previous notch 9, as shown in FIG. Alternatively, the pipes 5 and 6 are replaced with pipes having different thicknesses.

Advantageous Effects of the Invention As described above, according to the mold structure of the present invention, it is possible to provide a difference in the cooling effect between the part where the notch is formed in the pipe and the part where the notch is not formed. Cooling can be performed under appropriate cooling conditions, which can contribute to improving the quality of products.

Furthermore, since the pipe is detachable, it is possible to flexibly cope with a change in the cooling condition by additional processing of the cutout or replacement of the pipe, and there is no need to re-create the mold by changing the cooling condition as in the conventional case.

In addition, since the cooling medium is shielded by the pipe and does not come into direct contact with the mold, for example, in a water-cooled casting mold in which the mold temperature is as high as several hundred degrees, even if the mold is cracked. Even if cracks occur, the cooling water does not leak, and the destruction of the mold due to the infiltration of the cooling water into the crack portion can be prevented beforehand.

Also, according to the mold manufacturing method of the present invention, since the notched portion is formed in the pipe after checking the finished state of the product, each part of the product can be cooled under appropriate cooling conditions at the same time. In addition, there is an advantage that the cooling condition can be finely adjusted by selecting the processing position and the processing depth of the notch.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, a sectional view of a mold opened, FIG. 2 is a perspective view of a main part of a pipe, FIG. 3 is a second vertical sectional view, and FIG. It is sectional drawing which shows an example of the metal mold | die structure of this. 1 ... lower mold, 2 ... upper mold, 3,4 ... pipe insertion hole, 5,6 ... pipe, 5a, 6a ... cooling hole, 9 ... notch, W ...
… Products.

Claims (2)

(57) [Claims] 1. A pipe formed with a cooling hole through which a cooling medium flows, and a mold formed by filling a molten material into a mold and cooling and solidifying it to form a predetermined product. A pipe made of a metal material with good thermal conductivity and having a cooling hole is detachably inserted into the insertion hole, and a notch is formed locally on the outer peripheral surface of the pipe at a position corresponding to a specific part of the product. A mold characterized by the following. 2. A method of manufacturing a mold, comprising a cooling hole through which a cooling medium flows, filling a mold with a molten material, and cooling and solidifying the mold to form a predetermined product. A step of detachably inserting a pipe made of a metal material having good thermal conductivity and having a cooling hole into the inserted pipe insertion hole and performing molding while allowing a cooling medium to flow through the cooling hole; and a molded product. Forming a notch locally at a position corresponding to a specific part of the product on the outer peripheral surface of the pipe in accordance with the finished state of the die.