JPH10314889A - Metallic mold having ventilation hole and manufacture therreof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a formed product having good surface characteristic without executing casting flash removing treatment, etc., after forming by executing smoothening treatment to a cavity surface having a vent where a valve and vent pins are inserted and containing the vent pin part coated with metallic thermal- spraying, integrally with the vent pins. SOLUTION: Firstly, a vent 14 is provided for a prescribed metallic mold 10. Successively, the vent pins 16 are inserted into the vent 14. Further, the metallic thermal- spraying is applied on the whole cavity surface containing the end parts of the vent pins 16 at the cavity side, is applied with a robot and the inner wall is coated with the thermal-spraying film 20. Partially, as a finish process for smoothening the cavity surface and removing the casting flash, an electric discharge machining is used. In such a case, a metallic mold 10 is dipped into solution for machining and the electric discharge machining is executed to the whole cavity surface of the metallic mold 10 with an electrode to make the finish surface. Therefore, since the thermal-spraying film 20 and the surface of the vent pins 16 are ground under melting state and formed to good condition, it is unnecessary to execute the finish grinding treatment as the afterprocess.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold and a method of manufacturing the same, and more particularly, to a mold in which a vent pin is inserted to form a ventilation hole and a method of manufacturing the same.

[0002]

2. Description of the Related Art When a molded article is manufactured from a resin or other material, a compression molding method, an injection molding method, and other various molding methods are selected according to the molding material to be used and the quality of the molded article. . Especially when manufacturing resin molded products,
Injection molding is widely used.

When molding using these molding methods, it is necessary to degas air remaining in the cavity defined in the mold and gas generated during molding. As a means for this, a method of providing a ventilation hole in a molding die is often adopted.

However, according to this solution, if a mold provided with a vent hole for deaeration is used as it is, the burr is formed on the surface of the molded article due to the presence of the vent hole. A processing step such as removal of the burrs is required.

As one means for overcoming this kind of inconvenience, a mold has been proposed in which an exhaust chip having a fine through hole is loaded into the vent hole (JP-A-55-6553).
No. 5). However, according to this method, a gap is formed between the exhaust tip and the hole for inserting the exhaust tip, and as a result, burrs are generated in a part of the molded product around the gap. The presence of the burrs causes transfer to a molded product when molding using the mold. Therefore, when it is required that almost no burrs or the like are generated, this method cannot be said to be sufficient, and it is necessary to perform a deburring treatment depending on human hands after molding as in the past.

Further, in the above method, it is conceivable to fill a gap between the exhaust tip and a hole for inserting the exhaust tip by a brazing method. However, in this case, the heat at the time of brazing changes the hardness of the mold near the gap, which adversely affects the durability of the mold and the quality of the molded product. Further, when a drawn shape is formed on the surface of the cavity by performing a process using an etching method as a finishing process, the amount of etching varies due to the presence of the brazed portion, and a uniform drawn pattern cannot be obtained. For example, a difference occurs in the aperture shape and the aperture depth.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is intended to produce a molded article having good surface properties without performing deburring after molding. It is an object of the present invention to provide a mold having a vent hole capable of forming a mold and a method for producing the mold.

[0008]

According to the mold having the vent according to the present invention, the cavity surface having the vent into which the vent pin is inserted and including the vent pin portion coated with metal spray, It is characterized by being smoothed integrally with the vent pin.

By molding using this mold,
A molded product having good surface properties can be manufactured without performing deburring treatment or the like derived from the molded product.

In this case, it is more desirable that the bent pin and the sprayed metal are made of the same material. This is because the operation for exposing the ventilation holes becomes uniform, and the resulting molded product is also homogenized.

Further, according to the method of manufacturing a mold having a vent according to the present invention, a vent pin is inserted into a hole defined in the mold in advance, and the surface of the cavity including the vent pin portion is subjected to metal spraying. After coating, the surface of the cavity is smoothed integrally with the vent pin.

In this method of manufacturing a mold, a method may be used in which the surface of a cavity is coated with metal spraying, and then electric discharge machining is performed to expose the ventilation holes.
According to this method, precise processing is performed, and burrs do not occur.

Further, after the cavity surface is coated by metal spraying, at least the vent pin portion may be machined and then subjected to finish polishing in order to expose the air holes. Occurrence is as low as possible.

Further, the cavity surface may be coated by metal spraying, machined, and then the ventilation holes may be exposed by etching. According to this method, the finish polishing step after the mechanical processing is not required, and the surface of the cavity can be smoothed more than when the finish polishing method is used.

According to the method of the present invention, the ventilation holes can be exposed without generating or leaving burrs by smoothing at least the vent pin portion.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a mold having a vent according to the present invention and a method for manufacturing the same will be described.
This will be described in detail below with reference to the attached FIGS.

First, the schematic steps of the method for manufacturing a mold according to the present embodiment will be described step by step with reference to FIG.

As shown in FIG. 1A, a predetermined mold 10
A vent hole 14 is defined. In this case, when the mold 10 itself is a molded product, the ventilation holes 14 may be simultaneously defined at the time of casting. On the other hand, after the molding of the mold 10, the ventilation holes 14 are mechanically formed by using the drill 12. May be defined.

Next, as shown in FIG. 1B, a vent pin 16 is inserted into the vent hole 14. In this case, the vent pin 16 itself can be a sintered body formed by sintering metal fine particles.

Next, as shown in FIG. 1C, the entire surface of the cavity including the cavity side end of the vent pin 16 is subjected to metal spraying by the robot 18 so that the sprayed metal film 20 is formed.
Cover the inner wall of the cavity with.

In particular, the following three methods can be appropriately selected and used as a finishing step for smoothing the cavity surface and removing burrs.

FIG. 1D shows a case where the electric discharge machining method is used, in which the mold 10 is immersed in a machining solution 24 to form the mold 1.
The entire surface of the 0-cavity surface is subjected to electric discharge machining by the electrode 22 to obtain a finished surface.

On the other hand, FIG. 1E shows a case where a machining method is used. The entire surface of the cavity including the end of the vent pin 16 is cut by NC data or copying by a cutting device 26. Thereafter, finish polishing (not shown) is performed. In this case, after performing pre-processing such as masking and surface treatment (not shown) instead of the finish polishing, deburring is performed by etching processing in which the mold 10 is immersed in an etching solution 28 as shown in FIG. May be performed. As an etching method, a spray method shown in FIG. 2 may be used instead of the immersion method. In order to carry out the spraying method, a spray solution 32 is stored inside the housing 30. The solution 32 is fed to the top of the housing 30 by a pump 36 sent through a conduit 34 communicating with the bottom of the housing 30. A plurality of nozzles 38a to 38d are provided in the upper part of the interior of the housing 30, and the solution 32 sent through the pump 36 is sprayed onto the mold 10 placed on the support 40 to perform desired etching. Is applied to the mold 10. The solution 32 passes through the support 40 and reaches the bottom of the housing 30, and is recycled.

At this time, the vent pin 16 and the sprayed metal film 2
If 0 is made of the same material, the mold 10 can be used for electric discharge machining, finishing polishing after machining, or etching after machining.
The inner surface can be uniformly processed, and the cut surface is also uniform, which is preferable.

Next, FIG. 3 is an enlarged view of a vent hole portion in each operation step of FIG.

FIG. 3A shows a state in which the ventilation holes 14 are formed. Here, the diameter of the ventilation hole 14 can be appropriately selected according to the type of molding material and molding conditions. Through experiments, the gap between the fine particles of the bent pin formed by sintering the fine metal particles was selected to be 100 to 300 μm. As shown in the figure, the end of the vent hole 14 may be formed in a two-stage cylindrical shape in accordance with the diameter of the vent pin 16 to be inserted.

FIG. 3B shows that the vent pin 1 is
6 shows a state where 6 is inserted. The diameter of the vent pin 16 needs to match the diameter of the end of the vent hole 14, but the length in the axial direction can be appropriately selected. The material of the vent pin 16 is not particularly limited, but a material obtained by appropriately selecting and sintering cast iron, carbon steel, aluminum bronze, or bronze according to the purpose can be used. In this case, as described above, it is preferable to use the same material as the sprayed metal, because it is possible to avoid a difference in the surface properties of both materials during grinding. Further, the gap between the sintered fine particles of the vent pin 16 can be freely selected as needed.

FIG. 3C shows a state in which the surface of the cavity is metal-coated by thermal spraying. Here, the material of the metal for thermal spraying used is not limited, but preferably, aluminum bronze or bronze can be used. In this case, the thickness of the metal film 20 is preferably 1.
It is desirably about 0 to 3.0 mm.

FIG. 3D shows a state in which the surface of the cavity has been smoothed. When the smoothing process is performed by the electric discharge machining shown in FIG. 1D, the surfaces of the sprayed metal film 20 and the vent pins 16 are ground in a molten state, so that the finished state is good, and a finish polishing process is performed as a post-process. No need. Also, in the case where the machining is performed by the machining shown in FIG. 1E, after the cutting is performed by the cutting device 26, the finish polishing is performed.
Alternatively, by performing the etching process shown in FIG. 2 and performing the precision finishing, the deburring or the smoothing of the sprayed metal film 20 and the vent pin 16 can be performed, and the same effect as in the case of the electric discharge machining can be obtained.

The mold 10 and the method of manufacturing the same according to the present embodiment are basically as described above.
It is possible to provide a mold 10 for producing a molded product having good surface properties without performing deburring or the like of the mold having the vent hole 14 into which the vent pin 16 is inserted, and a method for producing the same.

[0031]

As described above, according to the mold having the vent according to the present invention and the method of manufacturing the same, the vent pin portion inserted into the vent and the surface of the cavity in the vicinity thereof are smoothed. Therefore, a molded article having good surface properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a manufacturing process of a mold according to the present embodiment. FIG. 1 (a) shows a step of defining a vent in the mold, and FIG. , A step of inserting a vent pin into a vent hole, FIG. 1 (c) shows a step of applying metal spraying to the surface of the cavity, FIG. 1 (d) shows an electric discharge machining step, and FIG. FIG. 1F shows a step of performing machining by performing immersion after the machining, instead of the electric discharge machining.

FIG. 2 is a schematic explanatory view showing a step of performing an etching process by using a spray method instead of the etching process by an immersion method of FIG. 1 (f).

FIGS. 3A and 3B are enlarged views of a vent portion in each step of FIG. 1. FIG. 3A shows a state in which a vent hole is formed, and FIG. 3B shows a vent pin inserted into the vent hole. FIG. 3C shows a state in which the surface of the cavity is coated with metal by thermal spraying, and FIG. 3D shows a state in which the surface of the cavity is smoothed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Die 12 ... Drill 14 ... Vent hole 16 ... Vent pin 18 ... Robot 20 ... Sprayed metal film 22 ... Electrode 24 ... Processing solution 26 ... Cutting device 28 ... Etching liquid 30 ... Housing 32 ... Spraying solution 34 ... Conduit Body 36 ... Pump 38a-38d ... Nozzle 40 ... Support

Claims (6)

[Claims] The present invention is characterized in that a cavity surface having a vent hole into which a vent pin is inserted and including the vent pin portion coated with a metal spray is smoothed integrally with the vent pin. A mold having pores. 2. The mold according to claim 1, wherein the vent pin and the sprayed metal are made of the same material. 3. A vent pin is inserted into a hole defined in a mold in advance, and the surface of the cavity including the portion of the vent pin is coated by metal spraying. Thereafter, the surface of the cavity is smoothed integrally with the vent pin. A method for producing a mold having an air hole, characterized by performing a treatment. 4. The method for manufacturing a mold according to claim 3, wherein
A method for manufacturing a mold having vents, wherein a cavity surface is coated with metal spraying together with a vent pin, and then at least the vent pin portion is subjected to electrical discharge machining and smoothing. 5. The method for manufacturing a mold according to claim 3, wherein
A method for manufacturing a mold having vent holes, comprising: coating a surface of a cavity together with a vent pin by metal spraying; thereafter, machining at least the vent pin portion, and further performing a finish polishing process to smooth the mold. 6. The method for manufacturing a mold according to claim 3, wherein
A method for manufacturing a mold having a vent, comprising: coating a surface of a cavity together with a vent pin by metal spraying; thereafter, machining at least the vent pin portion, and further performing an etching process to perform a smoothing process.