JPH01162558A - Manufacture of die material casting in hollow member - Google Patents

Abstract

PURPOSE:To reduce the working man/hour of the hole for an ejecter pin by holding a closing member and core print excess long part inside a cavity by providing them at the opening end part of a hollow member and after th cost-in forming a through hole on the hollow member by machining. CONSTITUTION:Plural pipes 3 are arranged on the wall of a die cavity 2 by providing the excess long part 6 for core print at the end part of an opposed side by welding and joining the closing member 5 of the same material as that of a die material to the opening end part of one part of the pipe 3. A molten metal is then poured via a runner into the cavity 2 to form the hollow part for an ejecter pin. After casting the excess long part 6 of the closing member 5 is cut off and after working a die face F the hole for the pin is opened by machining. The working man/hour of the hole for ejecter pin is reduced because the need for the machining of the hole making of the hollow part inside needing no high accuracy is eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a mold material in which a hollow member is cast, and in particular, a mold for molding a plastic product, etc., in which a large number of through holes for eject turbines are provided. The present invention relates to a manufacturing method that is suitable for application to a mold material that requires a plurality of through holes that require high opening accuracy to be provided on the mold surface side.

[Conventional technology]

The mold surface of molds for molding plastic products has many through holes through which ejector turbines are passed through to extrude the molded product. Conventionally, these molds for molding plastic products do not allow the mold material to be forged or cast. Manufacturing was completed by finishing the mold surface of the mold material to a shape and precision compatible with plastic products, and forming a through hole for the eject turbine by machining.

On the other hand, the through holes for the ejector turbine of these molds are designed to prevent the plastic flowing on the mold surface of the mold from leaking between the mold surface and the ejector turbine during plastic molding and adversely affecting product quality. Since there is a particularly strict requirement to ensure the accuracy of the opening position and dimensions, the processing requires careful consideration and requires a lot of man-hours.

Therefore, the inventor of the present invention has conducted intensive studies to make the through holes for the ejector pins of these molds easy to process while maintaining the required accuracy. Although precision is strictly required for the mold surface, accuracy is not required for parts other than the mold surface as long as they do not come into contact with the ejector turbine.
While casting the mold material, a hollow member is cast to form a part of the through hole during casting, that is, a part of the through hole other than the vicinity of the mold surface where relatively high accuracy is not required, and a part of the machine The aim is to eliminate the need for machining.

By the way, there is a known manufacturing method in which a hollow member of a predetermined shape is placed in the hollow part of a casting body and the hollow part is formed by casting the hollow part. As a method, for example, as shown in FIG. 5, extra lengths (52) are provided at both ends of the hollow member (51) to serve as baseboards, and the hollow member (51) is inserted through these extra lengths (52). 51) is held on the inner wall of the cavity (55) of the mold (53), and a casting part (54) is provided near the root of the extra length part (52), and these extra length parts (52) are held after casting.
2) and a method of forming a through hole in a cast product by cutting out the waste portion (54) (Japanese Unexamined Patent Publication No. 62-21454), as shown in FIG. 61
) A holding member (62) is provided with a fitting part (68) to be fitted into the inner diameter, and a baseboard part (69) is attached to one end of the holding member (62). 63
) is held on the inner wall of the cavity (64) of the mold (63), and then poured into the cavity (64) to form the hollow member (61).
) to form a through hole in a cast product (Japanese Patent Laid-Open Nos. 60-24258 and 62)
-21453) etc.

[Problem that the invention seeks to solve]

In recent years, as the scope of application of plastic products has expanded, competition with products from other fields has become more intense, and demands for improving dimensional accuracy and reducing costs have become more severe. There are also strict requirements for ensuring dimensional accuracy and cost reduction for the molds used.

As mentioned above, the mold surface of these molds for molding plastic products is provided with a large number of through holes through which the ejector turbine for extruding the molded product passes, and the openings of these through holes on the mold surface. Positional and dimensional accuracy is particularly required as it affects product quality.

However, in order to form these multiple through-holes during casting, eliminating the need for drilling holes by machining and reducing processing costs, the above-mentioned conventional technology is utilized to cast multiple hollow members into the mold material. When multiple through holes are formed all around, it becomes difficult to position all the openings of the mold surface formed by the ends of these hollow members or the holding members fitted into the ends within a predetermined accuracy. In other words, the casting body undergoes solidification shrinkage during solidification after casting, but this solidification shrinkage changes depending on the shape of each part of the casting, and the shrinkage is difficult to be uniform in each part, and furthermore, the hollow member itself that is cast Since the metal is easily deformed by the heat of the molten metal during casting, it is extremely difficult to position all of the plurality of openings formed on the surface within a predetermined precision.

When machining the openings on the mold surface side of a mold material in which a plurality of through holes are formed, if the positions and mutual distances of the openings of these through holes deviate, the openings or the through holes As a result, eccentric machining is required for the entire length, making it difficult to perform machining and ensure accuracy.

[Means for solving problems]

The present invention was made for the purpose of providing a method for manufacturing a mold material in which a hollow member is cast, which can solve the above-mentioned problems.
The gist is to close one open end surface of a hollow member by joining a closing member made of the same or equivalent material as the mold material, and to form a baseboard between the end of the closing member and the other open end surface of the hollow member. After attaching the extra lengths and holding the hollow member to the inner wall of the Ski mold cavity via these extra lengths, the metal is poured into the mold cavity and cast, and then from the closing member side surface of the mold material A through hole is formed by machining to open the space leading to the inner diameter of the hollow member.

[Effect]

In the present invention, since the hollow member is poured and cast in the cavity of the mold together with the closing member that closes one end face of the hollow member, the mold material after casting is formed between one end face of the hollow member and It has a hollow portion therein which is closed with a closing member and opened on the other end surface side.

Further, the hollow member to be cast is held at both ends by the inner wall of the mold cavity through the extra length formed by the end of the closing member connected to one open end face and the baseboard attached to the other open end face. Therefore, the hollow member can be reliably held at a predetermined position within the mold cavity, and the gas inside the hollow member, which expands due to heat during pouring, can be discharged through the open end that is not blocked. This allows the hollow member to be prevented from expanding or deforming or being damaged by the internal gas pressure during pouring.

In the present invention, after casting, a through hole is formed by machining to open the space from the surface of the mold material through the closing member part of the casting ring and from the surface of the mold material on the closing member side to the inner diameter of the hollow member. In this case, one surface of the mold material has high positional and dimensional accuracy (and it is possible to form a through hole that reaches the other surface), and the closing member is made of the same or equivalent material as the mold material. Therefore, even if it remains on the surface of the mold material, it will not impair the surface characteristics of the mold material.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Man 1! FIG. 1 is a cross-sectional view illustrating the concept of a mold according to a first embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view taken along the line A-A of the mold shown in FIG.

In FIG. 1 and FIG. 2, (1) is a mold,
The mold <1) has a mold cavity (2) corresponding to the product shape.
) is formed inside it.

(3) is a pipe, and the pipe (3) has a closing member (5) made of the same material as the mold material at one open end.
The extra length for the baseboard (6) provided at the end of the skin joint of the closure member (5) and the anti-occlusion member (
5) is fixed to the wall of the mold cavity (2) via the baseboard extra length (4) provided at the open end of the side, and is attached to the part forming the hollow part in the mold cavity (2). They are arranged respectively.

In this example, a mold material for plastic molding was cast with the above configuration, but as shown in FIGS. 1 and 2, the mold surface (the surface indicated by F in the figures) A large number of pipes (3) to which the above-mentioned closing member (5) is joined are arranged in the mold cavity (
2) Molten metal was poured into the inside to form a number of hollow parts for eject turbines. Then, for the mold material after casting, the extra length part (4) for baseboard of the closing member (5) protruding toward the mold surface F side is removed, and after processing the mold surface F, the mold surface F side is By making the opening more lathe, the hole for the eject turbine can be easily formed with a clearance accuracy that prevents the plastic flowing on the mold surface F during molding from leaking between the hole and the Nijief coupin, and each position is also within a predetermined accuracy. Holes other than the side of the mold surface F, where accuracy is not strictly required as long as they do not come into contact with Nijiev Coupin, are cast pipes (
By forming the through hole in 3) on the inner diameter surface, machining of this portion could be made unnecessary.

In addition, in this example, the diameter of the bottle hole on the mold surface F is 10 mm, and the inner diameter of the pipe (3) is
(Pin hole diameter D = 1hm) + (Tolerance for deviation in distance between center axes of pin hole diameter = 0.5 mm) + (Tolerance for deviation in distance between center axes of pipes to be cast; i.e. Experienced value of deviation that occurs in normal casting = 211II11
)", and by setting the outer diameter of the closing member (5) to be the same or larger than the inner diameter of the pipe (3), the bottle hole on the mold surface F side is The bottle hole machined in the closing member (5) exposed at the site and opened on the cough-shaped surface F side is ensured to communicate with the inner diameter of the pipe.

Although the plastic molding die according to this embodiment described above has a large number of holes for eject turbines, the accuracy of the holes on the mold surface side is ensured, and the number of man-hours required for machining these holes for eject turbines is large. An effect of reducing 4gB was obtained.

In addition, in this example, welding was used to join the closing member and the pipe, but this ensures that the joint between the two is maintained reliably during casting, and that molten metal does not penetrate into the inner diameter side from the joint. However, other joining methods may also be applied, such as screw joining.

In addition, in this example, the closing member was made of the same material as the mold material, but when using a material with good workability, it is possible to use a hard material for the pin while making the mold material It is also possible to achieve an effect that cannot be achieved by any method other than the method of the present invention, which is to facilitate the machining of holes and reduce the machining cost.

First lining Figure 3 is a longitudinal sectional view illustrating the concept of a mold according to a second embodiment of the present invention.

This embodiment is the same as the above-mentioned first embodiment, except that the structure of the open end of the pipe to be cast is different from the closed end, and redundant explanations will be omitted here. It shall be.

In Fig. 3, (11) is the mold, (12) is the mold cavity, θ9 is the pipe, 09 is the closing member, and 0ω is the extra length for the skirting board attached to the closing member 0ω, and these are the extra lengths for the baseboard attached to the closing member 0ω. This is similar to the first embodiment. 08) is an open end member, the open end member 08) is made of a material having the same or equivalent processing characteristics as the mold material, and is joined to the open end surface on the anti-obstruction member side on the vibe side, Its outer diameter is approximately equal to that of the pipe 03), its inner diameter is a small-diameter hole through which gas can flow, and an extra length for baseboard 0 is attached to the opposite end of the joint.

In this embodiment with the above configuration, both end surfaces of the pipe 0 to be cast after casting are not exposed to the surface of the mold material, and these portions are comprised of two closing members θ and an open end member 08 with a small diameter hole.
), and by opening these parts by turning after casting, it is possible to obtain a mold in which through holes with high positional and dimensional accuracy are formed at both ends of the opening.

The fourth example is a joint sectional view explaining the concept of a mold according to a third embodiment of the present invention.

This embodiment is similar to the first embodiment described above, except that the shape of the closing member that closes one open end surface of the pipe to be cast is different. It shall be omitted.

In Figure 4, Qυ is the mold, C! 1 is the mold cavity, Q31 is the pipe, and 1231 is the extra length for the skirting board of the pipe 1231, which is the same as in the first embodiment described above.QS1 is the closing member. The closing member (251) is made of a material that has the same or equivalent processing characteristics as the mold material, and the joint part with the pipe e■ has a diameter larger than the inner diameter of the pipe 031, and from this part the mold cavity Q The diameter of the extra length for baseboard (261) is made smaller than the diameter of the hole to be opened by turning after casting.

In this embodiment with the above configuration, the closing member (251) exposed on the surface of the mold material after casting is cut and removed when the part is lathed and opened, and the mold material is relatively thin, This is effective when applied to cases where it is difficult to ensure close contact between the mold material main body and the closing member QSl due to the material requiring a relatively low casting temperature.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view explaining the concept of the mold of the first embodiment of the present invention, Figure 2 is a longitudinal cross-sectional view of the A-A section of the mold shown in Figure 1, and Figure 3 is a cross-sectional view of the mold of the present invention. FIG. 4 is a vertical sectional view explaining the concept of the mold of the second embodiment of the present invention. FIG. 5 and FIG. 6 are the molds of the prior art. FIG. (1)-mold, (2)-mold cavity, (3)-
Pipe, (4) - Extra length for baseboard of pipe, (5) - Closure member, (6) - Extra length for baseboard of closure member. Patent applicant: Kobe Steel, Ltd. Representative Patent attorney: Akira Kanemaru - Figure 1 Figure 3

Claims (1)

[Claims] One open end surface of the hollow member is closed by joining a closing member made of the same or equivalent material as the mold material, and an extra length to be used as a baseboard is provided between the end of the closing member and the other open end surface of the hollow member. After attaching the hollow member to the inner wall of the mold cavity through these extra lengths, pour the metal into the mold cavity and cast. A method for manufacturing a mold material in which a hollow member is cast, characterized by forming a through hole by opening the space through machining.