JPH06304736A - Heat insulating die for die cast or squeeze cast - Google Patents

Abstract

PURPOSE:To provide a die where the temperature of the die before casting can be easily held in the target temperature range even when the die cast or squeeze cast of the semi-molten or partially solidified metal is repeatedly executed. CONSTITUTION:A heat insulating die consists of dies 1,3 having a product cavity 5, and holding dies 2,4 to fit and support by making use of the relationship between the contour and an insert, and the heat insulating material 7 corresponding to the contour of the dies is placed on the bottom of the insert hole 6. This constitution allows stable manufacturing of the product of excellent quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a heat insulating material suitable for die casting or squeeze casting of semi-molten or semi-solidified metal (hereinafter referred to as semi-molten metal) in a temperature range below the liquidus line and above the solidus line. This is a mold proposal.

[0002] Die casting or squeeze casting of semi-molten metal has an advantage over conventional die casting or squeeze casting of molten metal in that a product of better quality with less shrinkage holes and less internal defects can be obtained. Its development is in progress.

[0003]

2. Description of the Related Art In molding by a die casting method or a squeeze casting method, temperature control of a mold (product cavity surface temperature) is important for producing a high quality product. That is, if the mold temperature before molding is too low, the resulting product will have many void defects, and conversely, if the mold temperature is too high, the product will break when the product is taken out of the mold.

When a normal metal melt is used, for example, in the case of the die casting method, the melt is supplied into the sleeve and immediately pushed into the mold by a plunger for molding. At that time, since the surface temperature of the mold rises, it is possible to bring the mold temperature before the next molding to the target temperature range by cooling by spraying a mold release material containing a lot of water after taking out the product. A product of good quality can be obtained even if it is repeated.
Also, in the case of the squeeze casting method, cooling can be performed in the same manner to maintain the mold temperature before molding within the target temperature range.

In principle, these steps, ie, hot water supply into the sleeve → die casting → product removal → application of a mold release material to the mold ... Hot water supply into the sleeve are performed in the shortest possible time.

However, when a semi-molten metal is used, its temperature is lower than that of the molten metal. Therefore, even if the mold temperature is preheated to a target temperature in advance and the molding is started, the mold temperature does not rise so much. The temperature of the mold before the next molding is lowered by the cooling by spraying etc. and falls below the target temperature range, so that a product of good quality cannot be obtained. Therefore, in order to bring the mold temperature to the target temperature range, it is necessary to suspend the molding and preheat it, which lowers the productivity.

[0007]

DISCLOSURE OF THE INVENTION The present invention advantageously solves the above-mentioned problems, and can maintain the mold temperature before molding within the target temperature range even if repeated molding is performed by die casting or squeeze casting of semi-molten metal. The object of the present invention is to propose a heat retaining mold which is excellent in productivity and economic efficiency and which can stably obtain a product of good quality.

[0008]

The gist of the present invention consists of a die having a product cavity and a holding die that fits and supports the outer shape of the die in a nested relationship, and corresponds to the outer shape of the die at the bottom of the nesting hole. Heat-insulating die for die casting or squeeze casting with heat insulating material (first invention)
And

In the first invention, the heat insulating material is arranged such that it has a step corresponding to the thickness of the heat insulating material installed (second invention). In the first and second inventions, the heat insulating material is penetrated. And a spacer for controlling (3rd invention).

[0010]

The background of the present invention and its operation will be described below. As described above, in die-casting or squeeze casting of semi-molten metal, even if the mold is first preheated to the target temperature range, the mold temperature will decrease after repeated molding, and the mold temperature before molding (product cavity surface Temperature) cannot be maintained in the target temperature range, resulting in frequent occurrence of vacancy defects in the product, so experiments were conducted mainly with the aim of reducing the heat dissipation of the mold, and a heat insulating metal suitable for the above purpose was I found a new type.

That is, in order to prevent the temperature of the product cavity surface from lowering, the die is divided into a die having a product cavity and a holding die that fits and supports the outer shape of the die in a nesting relationship, and the die is placed at the bottom of the nesting hole. A heat retaining mold (first invention) in which a heat insulating material corresponding to the outer shape of the die is arranged. By using such a heat retaining mold, heat conduction from the die to the holding mold is reduced. As a result, the temperature drop of the die raised by heat conduction from the semi-molten metal during molding is reduced, and the die temperature (product cavity surface temperature) can be easily maintained in the target temperature range even if repeated molding is performed.

However, when molding is performed using the above heat retaining mold, burrs sometimes occur around the product. The burrs are generated by increasing the number of parts that were in the liquid phase when the burrs were in the semi-molten state, and vice versa. It is not preferable because it becomes a product having a composition (the composition of the alloy component is different between the liquid phase and the solid phase in the semi-molten state), the yield is lowered, and the man-hours are required to remove the burr.

Upon investigating the cause of the burr, when the heat insulating material disposed at the bottom of the nest hole has a large pressure generated in the cavity due to, for example, the injection pressure at the time of die casting or the injection speed, the pressure causes the die. Is pressed and the die is pressed, the heat insulating material is also pressed and the mounting thickness is reduced, and it is clear that there is a gap between the fixed die and the moving die. did.

Therefore, as a means for surely preventing the occurrence of the above-mentioned burr, the arrangement of the heat insulating material should have a step corresponding to the thickness of the heat insulating material device (second invention). This is to provide a spacer that penetrates the heat material (third invention), and by doing so, no gap is created between the dies that cause burrs.

Therefore, according to the above means, even if the pressure in the cavity generated at the time of molding is large, the burr around the product can be surely prevented, and the nest temperature can be easily maintained in the target temperature range even if the molding is repeated. As a result, good quality products can be obtained without lowering productivity and yield. Further, according to the above means, there is an effect that the life of the heat insulating material is extended and the replacement frequency thereof is reduced.

In the case of providing a spacer penetrating the heat insulating material, it is preferable to disperse a plurality of spacers evenly in the heat insulating material, and by doing so, heat conduction from the die to the holding die is performed through the spacer. The reaction force that opposes the pressing is dispersed, and the temperature distribution of the die and the amount of distortion of the die caused by pressing are made uniform. Also, for the spacer,
A metal of the same quality as that of the die or the holding type is preferably used, and a ceramic-based porous heat insulating material or the like is suitable as the heat insulating material.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a heat retaining mold of the present invention will be described with reference to the drawings. In Fig. 1, (a) is an explanatory view of the cross section of a heat insulating mold in which a heat insulating material corresponding to the outer shape of the die is arranged at the bottom of the nesting hole conforming to the present invention, and (b) is a front view of the heat insulating material of (a). 2A and 2B are an explanatory view of a cross section of a heat insulating mold conforming to the present invention, in which the arrangement of the heat insulating material has a step corresponding to the thickness of the heat insulating material mounted, and FIG. FIG. 4 is an explanatory view of the front surface of the heat insulating material of (a), and in FIG. 3, (a) is an explanatory view of a cross section of a heat insulating mold conforming to the present invention in which a spacer penetrating the heat insulating material is provided;
FIG. 3A is an explanatory diagram of the front of the heat insulating material of (a) and the spacers dispersedly arranged on the heat insulating material.

In these drawings, 1 is a fixed side die, 2 is a fixed side holding die thereof, 3 is a movable side die, 4 is a movable side holding die thereof, and the die 1 and 3 form a product cavity 5. Is forming. The fixed side holding die 2 and the movable side holding die 4 are provided with nesting holes 6 for fitting and supporting the outer shapes of the dies 1 and 3, respectively.

In FIG. 1 (a), the heat insulating material 7 corresponding to the outer shape of the dies 1 and 3 is provided at the bottom of each nesting hole 6, and in FIG. 2 (a), the thickness of the heat insulating material 7 is set. The heat insulating material 7 is provided at the bottom of each nesting hole 6 having the step seat 8 corresponding to the heat insulating material 7, and in FIG.
(6) and are arranged.

Further, FIG. 1 (b), FIG. 2 (b) and FIG. 3 (b)
As shown in Fig. 3, each corner of the heat insulating material 7 is cut in order to pass the set bolt. In FIG. 3 (b), the heat insulating material 7 has six through holes, and the spacers 9 are provided in these holes. The fitting is arranged.

Next, the heat retaining dies conforming to the present invention shown in FIGS. 1, 2, and 3 (hereinafter, heat retaining dies A and B, respectively).
And C) will be used to describe the result of die casting of a semi-molten Al alloy.

The dimensions of the heat insulating material 7 of the three types of heat retaining molds A, B and C are shown below. In addition, the thickness of the heat insulating material 7 was all adapted to the mounting thickness: 10 mm, and the material thereof was a ceramic type porous heat insulating material. Thermal insulation mold A ---- Vertical: 270 mm, Horizontal: 200 mm Thermal insulation mold B ---- Vertical: 240 mm, Horizontal: 200 mm Thermal insulation mold C ---- Vertical: 270 mm, Horizontal: 200 mm However, Fig. 3
As shown in (b), the spacer 9 is provided, and six through holes having a diameter of 30 mm are evenly distributed and opened in the heat insulating material 7, and the spacer 9 is fitted to these.

The die-cast material is lumped Al-Si: 4.0 ma.
The ss% alloy is heated to a semi-molten state at a temperature of 622 ° C and a solid phase ratio of 0.4, and is injected into a plate shape with a heat retaining mold A at an injection pressure of 120 MPa and an injection speed of 2.0 m / s (plunger speed). Product (length:
150 mm, width: 100 mm, thickness: 3.0 mm) were repeatedly molded. As a result, the pre-molding temperature of the dies 1 and 3 could be maintained in the target temperature range, and burrs were not generated at all, and a product of good quality could be stably obtained.

Then, the massive Al—Si: 4.0 mass% alloy is heated to a semi-molten state at a temperature of 622 ° C. and a solid fraction of 0.4,
Injection pressure: 12 using 3 types of heat insulation molds A, B and C
Plate-shaped product with 0 MPa and injection speed: 2.0 m / s (length: 150
mm, width: 100 mm, thickness: 3.0 mm) were repeatedly molded. As a result, in all cases using the heat retaining molds A, B and C, the pre-molding temperatures of the dies 1 and 3 could be maintained in the target temperature range.

However, in the case of using the heat retaining mold A, burrs were observed around the product as shown in FIG. 4, whereas in the case of using the heat retaining molds B and C, both of them were as shown in FIG. No burr was found at all as shown in FIG. Therefore, depending on the molding conditions and the like, it can be seen that the provision of the step washer or the spacer is extremely effective for preventing the occurrence of burrs.

FIG. 4 is an explanatory view showing a molded product taken out from the mold when the heat retaining mold A is used, and FIG. 5 is a molding taken out from the mold when the heat retaining mold C is used. It is explanatory drawing which shows a goods. In these figures, 10 is a product part, 11 is a burr part, 12 is a biscuit part, 13 is a gate part, and 14 is an overflow part. When the heat insulating mold A of FIG. Bali 11 has occurred.

Further, the results of examining the cross-sectional metallographic structure of the burr portion 11 are shown in FIGS. 6 (a) and 6 (b). Figure 6 (a) shows the burr
FIG. 6 (b) is an explanatory view of the cross-section metallographic structure photograph of FIG. In Fig. 6 (b), (a) is the overhanging tip part of the burr, where only the liquid phase of the semi-molten metal before solidification is solidified, (b)
Indicates a solidified portion with a larger liquid phase than the pre-molding semi-molten metal, that is, a solidified portion with a small solid fraction, and (c) a solidified portion with a solid phase proportion almost equal to that of the semi-molten metal before forming. ,
(D) is the product part. As is clear from these figures, the burr portion 11 has many portions that were in the liquid phase in the pre-molding semi-molten metal.

[0028]

Industrial Applicability The present invention relates to a heat retaining mold in which a heat insulating material is arranged between a die having a product cavity and a holding mold for the die. If the heat retaining mold of the present invention is used, die casting of semi-molten metal or The die temperature before molding (product cavity surface temperature) can be maintained in the target temperature range even if repeated molding is performed by squeeze casting, and burr can be prevented, resulting in excellent productivity and economic efficiency. It is possible to stably mold products of various qualities.

[Brief description of drawings]

FIG. 1 (a) is an explanatory view of a cross section of a heat retaining mold in which a heat insulating material corresponding to the outer shape of a die is arranged at the bottom of a nesting hole conforming to the present invention. (b) is an explanatory view of the front surface of the heat insulating material of (a).

FIG. 2 (a) is an explanatory view of a heat insulating type in which the arrangement of the heat insulating material has a step corresponding to the thickness of the heat insulating material mounted and which conforms to the present invention. (b) is an explanatory view of the front surface of the heat insulating material of (a).

FIG. 3 (a) is an explanatory view of a heat retaining mold which is provided with a spacer penetrating a heat insulating material and which conforms to the present invention. (b) is an explanatory view of the front surface of the heat insulating material and the spacers dispersedly arranged on the heat insulating material.

FIG. 4 is an explanatory view showing a molded product taken out from the mold when the heat retaining mold A is used.

FIG. 5 is an explanatory view showing a molded product taken out from the mold when the heat retaining mold C is used.

FIG. 6 (a) is a cross-sectional metallographic photograph of a burr portion.
(b) is an explanatory view of (a).

[Explanation of symbols]

 1 Die (fixed side) 2 Fixed side holding type 3 Dice (movable side) 4 Movable side holding type 5 Product cavity 6 Nesting hole 7 Heat insulating material 8 Stepped seat 9 Spacer 10 Product part 11 Biscuit part 13 Biscuit part 13 Gate part 14 Overflow Department

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chisato Yoshida 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture

Claims (3)

[Claims] 1. A die cast or squeeze comprising a die having a product cavity and a holding die that fits and supports the outer shape of the die in a nesting relationship, and a heat insulating material corresponding to the outer shape of the die is arranged at the bottom of the nest hole. Thermal insulation mold for casting. 2. The heat retaining mold for die casting or squeeze casting according to claim 1, wherein the heat insulating material is arranged with a step corresponding to the thickness of the heat insulating material. 3. The heat retaining mold for die casting or squeeze casting according to claim 1, further comprising a spacer penetrating the heat insulating material.