JPH08332560A - Product ejecting pin for die casting machine - Google Patents

Abstract

PURPOSE: To reduce worn quantity of an ejector port in a die and to eliminate a standing flash at a cast product side by softening the material at the tip part of an ejector pin in the die of a die casting machine more than the die material. CONSTITUTION: The ejector pin 1 in the die of the die casting machine is made of a copper and beryllium alloy having softer hardness then the one of the die or fitted to cover the copper and beryllium alloy-made cap 2 having the same outer diameter as the one of the ejector pin and almost the same length as the one of the tip part projected/retreated into a cavity in the die, with screw-in type into the ejector pin so as to be freely attachable/detachable. As a result, the worn quantity of the inner peripheral surface of the ejector port in the die is reduced and the worn quantity of the outer peripheral surface at the ejector pin side is increased, but in this case, the ejector pin can be returned back to almost the condition at the initial stage only by changing the ejector pin side and the standing flash developed at the cast product side can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a product extruding pin for extruding a product cast by a die casting machine from a cavity of a mold and releasing the product.

[0002]

[Technical Background] This type of extrusion pin is subject to a load of approximately 100 Kgf to 150 Kgf in the axial direction during the extrusion operation, although it depends on the shape of the cast product, the casting conditions, etc. Strength (rigidity) and wear resistance because it rubs against the inner peripheral surface of the extrusion hole (a hole formed to penetrate the extrusion pin from the back side of the mold toward the cavity so that it can be extruded) It is necessary to form it with an excellent material.

[0003]

2. Description of the Related Art Conventionally, the extrusion pin has been formed by using a hard SKD61 or the like, which is the same material as the material of the mold. As a result, not only the outer peripheral surface of the extrusion pin but also the inner peripheral surface of the extrusion hole of the die wears as a result of the pushing and sliding operation by the extrusion pin, and as a result, the outer peripheral surface of the extrusion pin and the inner periphery of the extrusion hole are There is a problem that the clearance between the two is widened, and casting burrs called vertical burrs are easily generated on the cast product side of the portion corresponding to the extrusion hole of the die. In that case,
A worn extrusion pin can be replaced with relative ease, but it is not easy to renew the die even if the extrusion hole of the die is worn, and even if only the extrusion pin is replaced Unless the mold is replaced, vertical burrs will continue to be generated on the cast product side.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and can prevent the expansion of wear of the extrusion hole of the mold, and as a result, only by exchanging the extrusion pin. It is intended to provide a product extruding pin for a die casting machine capable of suppressing the occurrence of vertical burrs generated on the casting product side of the portion corresponding to the extrusion hole of the die.

[0005]

To achieve the above object, the product extrusion pin for a die casting machine of the present invention has at least a tip portion projecting into and out of the cavity of a mold, which is softer than the material hardness of the mold, for example, copper- It is characterized by being formed of a beryllium alloy. Further, a cap formed of a material softer than the material hardness of the die is integrally or detachably covered and attached to the tip portion protruding and retracting in the cavity of the die.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The extrusion pin 1 according to the present invention is characterized by being formed of a material softer than the material hardness of the mold. By the way, in most cases, SKD61 is used as the material of the mold, and its hardness is Rockwell C hardness (HR
C) 43 to 46, and in a nitriding portion, it is often used with a Vickers hardness (HV) of 800 or more.

Although various materials are considered to be softer than the material hardness of the mold, they are selected in consideration of strength (rigidity), wear resistance, cost, etc. Among them, the copper-beryllium alloy is the material hardness of the mold. In the present invention, a copper-beryllium alloy is selected because it is softer, has higher strength, and is superior in wear resistance. By the way, the Vickers hardness (HV) of copper-beryllium alloy is about 237-251, and S
That of KD61 is about 937 to 985.

When the extruding pin 1 is made of a material softer than the material hardness of the mold, if the extruding pin is made of a soft material as a whole, the rigidity of the extruding pin becomes low. Is a tip part (usually about 3
Only about 0 mm) is preferably made of a material softer than the material hardness of the mold, for example, a copper-beryllium alloy.

When the tip portion of the extruding pin 1 is made of a material softer than the material hardness of the die, it may be joined to a portion other than the tip portion by some means. The cap 2 formed of a material that is softer than the material hardness of 1 is integrally or detachably attached to the cover.

That is, the cap 2 is formed of a material softer than the material hardness of the mold, for example, a copper-beryllium alloy, into a substantially cylindrical hat shape having the same outer diameter as the other portion of the extrusion pin 1, and the metal is A length that is approximately equivalent to the length of the tip that appears in and out of the mold cavity (for example, about 30 mm)
The cap 2 is integrally and detachably attached to the small-diameter tip portion 1a of the push-out pin 1.

At this time, the small diameter tip portion 1a of the extrusion pin 1 is
It is preferable to form the length such that the cap 2 exists as far as possible inside. Then, the cap 2 is reinforced by the small-diameter tip portion 1a of the extrusion pin 1
It is possible to increase the rigidity of the.

When the cap 2 is covered and mounted on the small-diameter tip end portion 1a of the extrusion pin 1, the cap 2 is integrally covered and mounted in a non-separable state by shrink fitting, adhesion or welding.
Alternatively, as in the illustrated embodiment, the small diameter tip portion 1a of the extrusion pin 1
A male screw 1a 'is formed on the outer peripheral surface, and the cap 2 is detachably screwed to be attached and covered.

Thus, the cap 2 made of a copper-beryllium alloy is screwed onto the small diameter tip portion 1a of the extruding pin 1 according to the present invention, and the conventional product made by using SKD61. Was set in the extrusion hole of the same mold, and the relationship between the pushing operation (number of times of sliding) and the wear amount was examined.

FIG. 2 shows the relationship between the wear amount of the outer peripheral surface of the extrusion pin and the sliding frequency, and FIG. 3 shows the relationship between the wear amount of the inner peripheral surface of the extrusion hole of the mold and the sliding frequency. is there. From the results shown in FIG. 2 and FIG. 3, the wear amount of the outer peripheral surface of the extrusion pin was larger in the product of the present invention than in the conventional product, and the wear amount of the inner peripheral surface of the extrusion hole of the mold was the product of the present invention. It is understood that the cases are less than the conventional products.

The "annealing" shown by the black squares in FIGS. 2 and 3 means that the conventional product formed of SKD61 is annealed. That is, when the extrusion pin 1 is made of a material softer than the material hardness of the mold, the SKD6
This is for reference, because it is considered to be advantageous in terms of cost if it can be used only by annealing the conventional product formed in 1. However, according to the results of the test, the annealed extruded pins (Vickers hardness (HV) is 222 to 223)
It was found that the amount of abrasion of the inner peripheral surface of the extrusion hole of the die was larger than that of the case of using the product of the present invention, which was unsuitable.

[0017]

Since the product extrusion pin for die casting machine of the present invention is constructed in this manner, the wear amount of the outer peripheral surface of the extrusion pin is SKD.
Although it is larger than the conventional product formed by No. 61, the wear amount of the inner peripheral surface of the extrusion hole of the mold can be made considerably smaller than that of the conventional product. Therefore, it is possible to prevent the expansion of wear of the extrusion hole of the die, and when the outer peripheral surface of the extrusion pin is worn and the clearance between the inner periphery of the extrusion hole of the die is expanded, replace the extrusion pin. It is possible to return to an almost initial state by simply performing the above operation, and as a result, it is possible to suppress the occurrence of vertical burrs that occur on the cast product side of the portion corresponding to the extrusion hole.

Further, according to the extrusion pin of the second aspect, since the tip portion (only) protruding and retracting in the cavity of the die is formed of a material softer than the material hardness of the die, it is used as an extrusion pin. There is no risk of damaging the strength (rigidity) of.

Further, according to the extrusion pin of the third aspect, since the cap formed of a material softer than the material hardness of the die is covered and attached to the tip portion protruding and retracting in the cavity of the die, the extrusion pin is formed. Not only does not impair the strength (rigidity), but also the strength (rigidity) of the cap protruding and retracted in the cavity of the mold can be made sufficient.

Further, according to the extruding pin of the fourth aspect, since the cap made of a material softer than the material hardness of the mold is detachably covered and attached, only the cap can be replaced easily. As a result, the replacement work becomes easier as compared with the case where the entire extrusion pin is replaced, and the material cost can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of implementing the present invention.

FIG. 2 is a graph showing the relationship between the wear amount of the outer peripheral surface of the extrusion pin and the number of times of sliding.

FIG. 3 is a graph showing the relationship between the wear amount of the inner peripheral surface of the extrusion hole of the die and the number of times of sliding.

[Explanation of symbols]

1 ... Extrusion pin 1a ... Small diameter tip 1a 1a '... Male screw 2 ... Cap

Claims (5)

[Claims] 1. A product extruding pin for a die casting machine, which is formed of a material softer than the material hardness of the die. 2. A product extruding pin for a die casting machine, characterized in that a tip portion protruding and retracting in the cavity of the die is formed of a material softer than the material hardness of the die. 3. A product extruding pin for a die casting machine, characterized in that a cap formed of a material softer than the material hardness of the mold is covered and attached to a tip portion protruding and retracting in the cavity of the mold. 4. The die casting machine according to claim 3, wherein a cap formed of a material softer than the material hardness of the mold is detachably covered and attached to a tip portion of the mold that appears in and out of the cavity. Product extrusion pin. 5. A material softer than the material hardness of the mold is
The product extruding pin for a die casting machine according to claim 1, 2 or 3 or 4, which is a copper-beryllium alloy.