JPH081308A - Method for taking out casting - Google Patents

Abstract

PURPOSE:To make a pin seat on the surface of a casting unnecessary by pressing a core with an ejector pin to detach the casting from a mold. CONSTITUTION:In a taking-out method for taking out the casting from the mold by detaching the casting from the mold with the ejector pin at the time of opening dies after casting, a process for selecting a resin having such strength as not to deform by exceeding the permissible value at the time of pressing with the ejector pin 18 and low thermal conductivity, a process for manufacturing a core (n) with the resin selected in the above process and a process for pressing the position which does not cast in with the molten metal in a part of the core (n) with the ejector pin 18 are included.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of taking out a cast product, in which the cast product is ejected from a mold by an extrusion pin when the mold is opened after casting and the cast product is taken out of the mold.

[0002]

2. Description of the Related Art A technique for ejecting a product by pushing the product away from a mold with an extrusion pin when the mold is opened is a practical method.
No. 92062. This technology uses a double-structured extrusion pin consisting of an outer cylinder and a central shaft housed inside the outer cylinder to push the product away from the mold, and the tip of the extrusion pin is burred. Even if the product sticks to the product, the sticking out can be prevented by projecting the central axis.

[0003]

However, according to the above-mentioned conventional method, since the product is directly extruded by the extruding pin, it is necessary to provide the product with a pin seat for receiving the extruding pin. Therefore, it is necessary to perform work such as scraping off the pin seat in a later step, which causes a problem of increased cost and reduced work efficiency.
The technical problem of the present invention is to manufacture a core from a resin that does not collapse or deform due to the pushing force of the extrusion pin, and press the portion of the core that was not cast in the molten metal with the extrusion pin. This allows the cast product to be ejected from the mold without damaging it, and further, by allowing a part of the core and the extrusion pin to engage with each other, the core can be removed from the extrusion pin before casting. It enables the positioning by.

[0004]

[Means, actions, and effects for solving the problems]

[Means according to Claim 1 for Solving the Problem] The above-mentioned problem is solved by a method for taking out a cast product having the following features. That is, in the method for taking out a cast product according to claim 1, in the method for taking out a cast product in which the cast product is ejected from the mold by an extrusion pin when the mold is opened after casting, and the cast product is taken out from the mold, A step of selecting a resin having a low thermal conductivity and having a strength that does not deform beyond an allowable value even when subjected to pressure, a step of manufacturing a core by the resin selected in the step, and a mold opening, And a step of pressing a portion of the core that is not cast in the molten metal with the extrusion pin. [Operation of the invention described in claim 1] According to the present invention,
The resin, which is the material of the core, has such strength that it does not deform beyond the allowable value even if it is pressed by the extrusion pin.
Further, a part of the core that is not surrounded by the molten metal (hereinafter referred to as an extrusion pin receiving portion) is in contact with the mold and is cooled by the mold, so that the heat of the molten metal is directly received. There is no. Furthermore, since the resin has a low thermal conductivity, it is difficult for the heat of the molten metal to reach the extrusion pin receiving portion and its vicinity through the body of the core. Therefore, the temperature of the extrusion pin receiving portion of the core does not rise sharply even during casting, and the strength is substantially maintained before casting. Therefore, even when the pushing pin receiving portion receives the pushing force of the pushing pin when the mold is opened, the pushing pin receiving portion does not deform beyond the allowable value. Therefore, by pressing the push-pin receiving portion of the core with the push-pin, it becomes possible to reliably separate the cast product in which the core is cast from the mold. Since the core is made of resin, it can be easily extracted from the cast product by softening it with heat after removing the cast product from the mold. [Effect of the invention described in claim 1] According to the present invention,
By pressing the extrusion pin receiving portion of the core with the extrusion pin, the cast product can be reliably separated from the mold. For this reason, it is not necessary to provide a pin seat for receiving the extrusion pin on the surface of the cast product as in the conventional case, and work for scraping off the pin seat in a later step becomes unnecessary. As a result, the cost can be reduced and the work efficiency can be improved.

[Means according to Claim 2 for Solving the Problems] The above-mentioned problems can be solved by a method for taking out a cast product having the following features. That is, the method for taking out a cast product according to claim 2 is the method for taking out a cast product according to claim 1, wherein in the step of manufacturing the core, a part of the core that is not surrounded by the molten metal is used. An engaging portion that engages with the push pin is formed. [Operation of the invention described in claim 2] According to the present invention,
An engaging portion that engages with the extrusion pin is formed in a part of the core that is not cast in the molten metal, that is, in the extrusion pin receiving portion. Therefore, when the core is set in the cavity of the mold, the core can be positioned at the prescribed position by engaging the engaging portion of the core with the push pin. Therefore, it is possible to omit the skirting part for positioning the core with respect to the mold. [Effect of the invention described in claim 2] According to the present invention,
Since the core print part of the core can be omitted, the manufacturing cost of the core can be reduced.

[0006]

【Example】

[First Embodiment] A method for taking out a cast product according to a first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Here, FIG. 1 is a longitudinal sectional view of a main part of the casting apparatus 10 according to the present embodiment, and FIG. 2 is a detailed view of a II part of FIG.
The casting apparatus 10 includes a fixed die 12 and a movable die 14, and a cavity 16 for forming a casting product in the die in a clamped state as shown in FIG.
Is formed. Further, inside the cavity 16, a core n for forming a cavity inside the casting is positioned at a predetermined position. The fixed mold 12 is attached to the core n.
A skirting board portion nh for positioning the core n is formed in a portion sandwiched by the movable mold 14 and the molding surface 12f of the fixed mold 12 on the back surface side of the core n.
A small-diameter convex portion nk that comes into contact with is formed. Further, a large-diameter convex portion np that is in contact with the molding surface 14f of the movable mold 14 is formed on the surface side of the core n. Here, as the material of the core n, a synthetic resin such as polycarbonate having a high glass transition point and high impact strength and ductility is preferably used.

As shown in FIG. 2, on the molding surface 12f of the fixed mold 12, a concave portion 12 that engages with a tip of the small-diameter convex portion nk at a portion where the small-diameter convex portion nk of the core n contacts.
d is formed. Further, a through hole 12h is formed in the center of the recess 12d in the mold clamping direction (vertical direction in the drawing), and the push pin 18 is slidably inserted into the through hole 12h. Then, the extrusion pin 18 is moved by the extrusion device (not shown) to the molding surface 1 of the fixed mold 12.
By being operated so as to project from 2f, the core n
The tip of the small-diameter convex portion nk (hereinafter, referred to as an extrusion pin receiving portion nf) is pressed by the extrusion pin 18 in a direction away from the fixed mold 12. Here, in the through hole 12h, the molding surface 12f side functions as a positioning guide portion for the extrusion pin 18, and in this portion, the fixed mold 12 and the extrusion pin 18 are provided.
The clearance between and is set small. Also,
On the lower side of the positioning guide portion, a relatively large clearance is set between the fixed die 12 and the extrusion pin 18 to prevent the extrusion pin 18 from being galled.

Further, a cooling water passage 12w is provided around the through hole 12h so that the tip end of the extrusion pin 18, the recess 12d of the molding surface 12f and the periphery thereof are cooled. Thereby, the molding surface 12f
Push pin receiving part n of the core n engaged with the recess 12d of
f is efficiently cooled. Further, since the polycarbonate, which is the material of the core n, has a low thermal conductivity, it is difficult for the heat of the molten metal to reach the extrusion pin receiving portion nf through the main body of the core n. Therefore, the extrusion pin receiving portion n
The temperature of f does not rise sharply even during casting, and even when casting is completed and mold opening is performed, its strength is maintained in substantially the same state as before casting and does not soften. further,
Small-diameter convex portion nk of the core n and concave portion 1 of the molding surface 12f
The clearance between the two nks and 12d in the engaged state with 2d is set to be small, and as described above, the recess 12d of the molding surface 12f and its periphery are cooled to accelerate the solidification of the molten metal. Therefore, it becomes difficult for the molten metal to enter between the extrusion pin receiving portion nf of the core n and the recess 12d of the molding surface 12f, and the occurrence of burrs or the like is suppressed.

Next, a method for taking out a cast product according to this embodiment will be described. First, with the mold opened, the small-diameter protrusion nk of the core n is inserted into the recess 12d of the fixed mold 12.
The core n is set in the stationary mold 12 so that Next, in this state, the movable mold 14 is moved to perform the mold clamping, and as shown in FIG. 1, in the state where the mold clamping is completed, the molten metal flows from the plunger sleeve (not shown) into the cavity 16 Is pressed into. Then, when the molten metal that has been press-fitted is solidified after a lapse of a predetermined time, the mold is opened, and the push pin receiving portion nf of the core n is pushed by the push pin 1.
Pressed by 8. Here, as described above, the extrusion pin receiving portion nf of the core n is maintained in a state where both the impact strength and the ductility are high even when the die is opened after the casting is completed. Therefore, even if the pushing force of the push pin is received, the push pin receiving portion nf does not deform beyond the allowable value, and the cast product can be reliably separated from the fixed mold 12. Since the core n is made of resin, it can be easily extracted from the cast product by taking out the cast product from the mold and then softening it by heat. As described above, according to the present embodiment, it is not necessary to provide a pin seat for receiving the extrusion pin 18 on the surface of the cast product as in the conventional case, and work for scraping off the pin seat in a subsequent step is not necessary. As a result, the cost can be reduced and the work efficiency can be improved.

[Second Embodiment] A method for taking out a cast product according to a second embodiment of the present invention will be described below with reference to FIGS. 3 and 4. Here, FIG. 3 is a cross-sectional view of a main part of the casting apparatus according to the present embodiment, and FIG. 4 is a vertical cross-sectional view illustrating an application example of the method for taking out a cast product according to the present embodiment. The core n used in this embodiment is the core n used in the first embodiment in which a small-diameter convex portion nk is formed with a recess nx that engages with the pushing pin 28. Accordingly, when the core n is set in the cavity 26 of the mold, the core n can be positioned at a prescribed position by engaging the recess nx of the core n and the push-out pin 28. become able to. That is, the concave portion nx corresponds to the engaging portion of the present invention.

Next, a method for taking out a cast product according to this embodiment will be described. First, the mold is opened, and the extrusion pins 28 are protruded from the molding surface 22f of the fixed mold 22 by a predetermined dimension.
The core n is set in the fixed mold 22 so that x is engaged. Next, in this state, the movable mold (not shown) is moved to perform mold clamping. Then, with the mold clamping completed, the molten metal is pressed into the cavity 26 from the plunger sleeve (not shown). In this way, when the molten metal that has been press-fitted solidifies after a predetermined time has elapsed, the mold is opened and the core n is pressed by the extrusion pin 28. As a result, a cast product in which the core n is cast is ejected from the fixed mold 22 and the cast product is taken out. As described above, in this embodiment, since the core n is positioned at the specified position of the cavity 26 by engaging the core n and the push-out pin 28, the core n is used as a mold. The skirting board nt or the like for positioning with respect to it is not necessary, and the manufacturing cost of the core n can be reduced. Further, as shown in FIG. 4, even in the structure in which the core n is supported and positioned from the surroundings, it is not necessary to form the peripheral surface nt of the core n with high precision as in the conventional case, and the manufacturing cost is reduced. Will be able to

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a casting apparatus according to a first embodiment of the present invention.

FIG. 2 is a detailed view of section II in FIG.

FIG. 3 is a longitudinal sectional view of a main part of a casting apparatus according to a second embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing a method for taking out a cast product according to a second embodiment of the present invention.

[Explanation of symbols]

n Core nh Baseboard part nk Small diameter convex part nf Pressing pin receiving part (a part of the core that was not cast in the molten metal) nx Recessed part 12 Fixed mold 14 Movable mold 18 Extrusion pin

Front Page Continuation (72) Inventor Shuichi Tomitaka 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (2)

[Claims] 1. A method for removing a cast product, wherein a cast product is pushed away from a mold by an extrusion pin when the mold is opened after casting, and the cast product is taken out of the mold. Of a resin that has a strength that does not cause deformation and has a low thermal conductivity, a step of manufacturing a core from the resin selected in the above step, and a step of forming a part of the core when the mold is opened. And a step of pressing a portion not cast in the molten metal with the extrusion pin. 2. The method for removing a cast product according to claim 1, wherein in the step of manufacturing the core, an engaging portion that engages with the extrusion pin is provided in a part of the core that is not cast in the molten metal. A method for taking out a cast product, which comprises molding.