JP2007038513A - Heat-storing mold structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent, in a mold in which the core and the die base are joined and integrated, excessive heat dissipation to make the mold temperature around the molding cavity part uniform, and to prevent disadvantages such as molding defects from being produced. <P>SOLUTION: In the fixed mold 1 in which the core 3 for forming the molding cavity part 4 and the die base 2 are joined and integrated, of the joined surfaces of the core 3, on at least the surface of the opposite side to the cavity part 4 there are formed a plurality of heat insulating grooves 10, and, in the inside of the core 3 there are formed a plurality of saccate heat insulating holes 11 extending from the surface on which the heat insulating grooves 10 are formed to the cavity surface side, and their insides are made to be an air layer. These heat insulating grooves 10 and heat insulating holes 11 are arranged more densely in the core 3 in the opposite side of the runner 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for making the temperature around a cavity of a mold uniform when casting automobile parts or the like with molten aluminum, for example.

Conventionally, when molding a molded product such as an optical disk with a mold, a uniform transfer molded product can be molded at a low cost with a short molding cycle. Change the thermal conductivity so that the thermal conductivity of the wall of the temperature control channel corresponding to the part to be weakly cooled is lower than the thermal conductivity of the wall of the temperature control channel corresponding to the part to be strongly cooled. Such a technique (for example, refer to Patent Document 1) is known.
JP 2000-826

Also, as a mold for molding a molded product such as an optical disc, a mirror plate on which a cavity is formed for the purpose of improving transferability, enabling high cycle molding, and preventing the thermal influence of the protruding portion, Also known is a technique (see Patent Document 2) in which a mold plate provided with cooling means is coupled, a mounting plate is coupled to the back side of the mold plate, and a heat insulating groove is formed on the coupling surface of the mold plate and the mounting plate. It has been.
JP 2002-347093 A

By the way, when aluminum parts such as automobile parts are cast, aluminum molds on the runner side where molten aluminum is injected become hot and require a lot of cooling, but the mold parts far from the runners radiate heat. Even when a mold release agent is applied every cycle, for example, the mold release agent cannot be completely dried, and discoloration and hot water wrinkles are likely to occur due to residual in the cavity. There is a problem that the appearance quality is adversely affected, such as a shape defect is likely to occur in a portion where deficiency occurs.
In particular, many of the molded parts of covers, such as automotive parts, have a concave shape, and the concave shape of the mold tends to escape heat more radially than the convex shape, so the mold temperature must be maintained at an appropriate level during production. However, the above-described poor appearance quality has been a problem.

  Accordingly, the present invention provides a mold in which a core in which a molding cavity portion (concave portion) is formed and a die base are combined and integrated, thereby preventing excessive heat dissipation and uniformizing the mold temperature around the molding cavity portion. The object is to prevent defects such as molding defects by maintaining the temperature at an appropriate level.

  In order to achieve the above object, according to the present invention, in a mold in which a core in which a molding cavity portion is formed and a die base are coupled and integrated, at least a cavity surface of the coupling surface with the die base is defined with respect to the core. An arbitrary number of heat insulating grooves are formed on the opposite surface, and an arbitrary number extending in a direction substantially perpendicular to the heat insulating grooves from the surface on which the heat insulating grooves are formed toward the cavity surface side in the core. Insulation holes were formed.

In this way, if a heat insulating groove is provided on the joint surface between the core and the die base where the molding cavity is formed, the heat of the core can be prevented from being transferred to the die base and radiated, and the core If a heat insulating hole is provided to extend the heat insulating groove in a substantially right angle direction toward the cavity surface side, it is possible to prevent the heat of the cavity from diffusing to the surroundings. For this reason, by combining the heat insulating groove and the heat insulating hole, heat storage in the molding cavity and uniform heat around the cavity can be effectively achieved.
Here, of the connecting surface with the die base, the surface on the opposite side to the cavity surface is the part where the contact area with the die base is large, and if heat insulating grooves are provided in such places, many heat insulating grooves are formed. It is possible to enhance the step heat effect, but it is optional to be provided on the other side surface, upper surface, lower surface or the like.
In addition, as a heat insulation groove | channel or a heat insulation hole, it is sufficient to just make the inside hollow and to interpose air.

Further, in the present invention, the heat insulating grooves and the heat insulating holes are arranged with a higher density than the core on the runner side for injecting the molding material into the cavity to the core on the opposite side of the runner. I set it up.
In the mold on the opposite side to such a runner, particularly suitable mold temperature is difficult to maintain, and because it is a place where the temperature tends to be lower than the optimum temperature, if the heat insulation grooves and heat insulation holes are arranged with a high density, The heat radiation from the same part can be suppressed and the heat around the cavity part can be made more uniform.

  In a mold in which the core and the die base are combined and integrated, a heat insulating groove is formed on the connecting surface of the core with the die base, and a heat insulating hole is formed inside the core so that the periphery of the molding cavity portion is formed. The mold temperature can be made uniform, and problems such as molding defects can be prevented. At this time, it is more effective to increase the density in the core on the side opposite to the runner and provide the heat insulation grooves and heat insulation holes.

Embodiments of the present invention will be described with reference to the accompanying drawings.
Here, FIG. 1 is an explanatory view showing an example of a mold structure according to the present invention. Is an explanatory view showing the heat insulating effect of the heat insulating groove, and FIG. 3 is an explanatory view of a conventional mold structure.

  The heat storage mold structure according to the present invention prevents excessive heat dissipation and appropriately maintains the mold temperature around the mold cavity part in a mold in which the core in which the mold cavity part is formed and the die base are combined and integrated. In this embodiment, the case cover, which is an automobile part, is applied to a mold for casting aluminum, and the mold structure of the present invention will be described. Prior to this, a conventional structure of such a mold will be described with reference to FIG.

  In a mold for manufacturing a case cover, a fixed mold 1 shown in FIG. 3 has a die base 2 and a core 3 coupled and integrated. The core 3 is formed with a molding cavity portion 4, and this fixed mold 1 is also formed. A movable mold (not shown) is disposed on the cavity surface side of 1 so that the mold clamping mold can be opened in the horizontal direction. A runner 5 for pouring molten aluminum is provided on the ground side (lower side) of the fixed mold 1.

  In such a mold structure, when high temperature molten aluminum is injected from the runner 5 and the case cover is molded by the molding cavity portion 4, the ground side where the runner 5 is located becomes hot, while the top side (upper side) is There is little flow of the molten metal, and the shape of the molding cavity 4 is close to a simple concave shape, and heat is likely to escape in the radial direction compared to the convex shape of the movable core, so that it often does not reach an appropriate temperature. For example, as shown in (b), when the release agent is applied by the release agent applicator 6, the release agent remains in an undried state, and discoloration, patterns, hot water wrinkles, etc. occur in the cast product. This is as described above.

Therefore, the present invention has been made to prevent such conventional problems, and will be described below with reference to FIGS.
It should be noted that the same numbers are used for the same components as in the conventional case.

  The fixed die 1 is a mold structure in which a core 3 having a molding cavity portion 4 and a die base 2 are coupled via a coupling surface, and on the opposite side of the coupling surface of the core 3 from the molding cavity portion 4. A plurality of heat insulation grooves 10 are formed in the vertical direction on the surface, and a plurality of bag-like heat insulation holes 11 are formed in the core 3 from the heat insulation groove 10 formation surface side toward the cavity surface side. These heat insulating grooves 10 and heat insulating holes 11 are air cavity layers.

Here, when two objects having different temperatures are brought into contact with each other, heat transfer occurs. However, it is known that the thermal conductivity varies depending on the material, and that the larger the contact area, the faster the heat conduction. The thermal conductivity κ of the substance (the amount of heat flowing for 1 ^second through the plate 1 m ² when there is a temperature difference between both ends of the plate having a thickness of 1 mm) is 428 W / m / min at a temperature of 0 ° C. in the case of copper. In the case of K and iron, it is 83.5 W / m / K at a temperature of 0 ° C., but in the case of air, it is also known to be 0.0241 W / m / K at a temperature of 10 ° C.

For this reason, as shown in FIG. 2, if the air layer 13 is interposed between the bonding surfaces of the two substances, the movement of heat is blocked, and the heat insulating effect is exhibited, and the heat insulating groove 10 shown in FIG. It can be seen that the amount of heat radiated from the core 3 through the die base 2 to the outside can be limited.
At this time, since the surface opposite to the cavity surface side has the largest area, the heat insulating groove 10 is formed at least in this portion, but it is formed on the side surface, the upper surface or the lower surface of the coupling surface. Is optional.

  Also, by providing the heat insulating holes 11 in the same core 3, heat diffusion is prevented, and it is effective for enhancing the heat storage effect of the core 3 and making the temperature of the molding cavity portion 4 uniform. .

By the way, the heat insulating grooves 10 and the heat insulating holes 11 increase the density on the top side (upper side) away from the runner 5 by the air layer as described above, and conversely, cooling water on the ground side (lower side) close to the runner 5. There are many holes.
Thereby, the temperature of the molding cavity part 4 is made more uniform.

In addition, when the mold temperature of the core 3 of the present embodiment was measured, the temperature of the core 3 in FIG. 1 was 140 ° C., which was 100 ° C. in the conventional example of FIG. The mold temperature was increased.
In addition, defects such as discoloration and hot water wrinkles in the molded product due to poor drying of the release agent were also suppressed, and the appearance correction rate of the conventional molded product was 40%, but in the present invention, it was suppressed to 15%. This also proves the effectiveness of the present invention.

In addition, this invention is not limited to the above embodiments. What has substantially the same configuration as the matters described in the claims of the present invention and exhibits the same operational effects belongs to the technical scope of the present invention.
For example, the product shape and the like are examples.

  When casting automobile parts or the like with a mold, molding defects such as hot water wrinkles, discoloration, and shape defects caused by the mold temperature not reaching an appropriate temperature can be prevented with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows an example of the metal mold | die structure which concerns on this invention, (a) is a front view of the type | mold of one side, (b) is sectional drawing which shows the coupling | bond part of a core and die base Explanatory drawing which shows the heat insulation effect of a heat insulation groove Illustration of conventional mold structure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fixed mold, 2 ... Die base, 3 ... Core, 4 ... Molding cavity part, 5 ... Runner, 10 ... Heat insulation groove, 11 ... Heat insulation hole.

Claims (2)

A mold in which a core in which a molding cavity portion is formed and a die base are combined and integrated, and the core has an arbitrary number of surfaces on at least the surface opposite to the cavity surface among the coupling surfaces with the die base. A heat insulating groove is formed, and an arbitrary number of heat insulating holes extending in a direction substantially perpendicular to the heat insulating groove from the surface on which the heat insulating groove is formed to the cavity surface side are formed inside the core. Thermal storage mold structure characterized by The heat insulating groove and the heat insulating hole are disposed with a higher density in the core on the side opposite to the runner than the core on the runner side for injecting the molding material into the cavity. The heat storage mold structure according to claim 1, wherein