JPS5831292B2 - Thermosetting resin mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold for molding a thermosetting resin, and particularly to a mold that takes into consideration the removal of resin burrs that occur when molding a resin.

Conventional thermosetting resin molds have been coated with hard chrome plating to improve non-adhesion with the resin, corrosion resistance, and abrasion resistance of the mold.

However, hard chrome plating does not have sufficient non-adhesive properties with resin, and it is difficult to remove resin burrs that occur along the parting surface and air vents of the mold, so an external mold release agent must be applied to the mold surface. Therefore, it was necessary to ensure non-stick properties.

Currently, there are various types of external mold release agents, but
None of them can withstand continuous shots, and it is necessary to apply uneven coating during molding work, and it is difficult to apply uniformly. Moreover, once resin burrs are stuck to the mold due to insufficient application, it is difficult to remove the resin burrs. It had various drawbacks.

Furthermore, it is difficult to obtain a uniform coating especially with mold release agents external to the mold, which is said to withstand continuous shots to some extent.
When applied to the cavity, it has the disadvantage of affecting the appearance and dimensions of the molded product, and it is technically impossible to partially treat specific areas such as the parting surface or air vent area.

In addition, thermal deterioration cannot be avoided with any external mold release agent.
As the mold releasability from the resin deteriorates due to thermal deterioration, there is a drawback that the surface of the mold gradually becomes dirty with repeated application.

In order to eliminate the drawbacks of these external mold release agents, it has been considered to apply a film of tetrafluoroethylene resin to the mold surface, and it has been applied to kitchen utensils such as hot plates, but due to the lack of hardness of the film and Due to the lack of adhesion between the film and the substrate, it cannot be applied to transfer molds or injection molds that require dimensional accuracy.

Because of these drawbacks, molders of thermosetting resins have traditionally been forced to remove resin particles with metal brushes, as air blowing with an air gun alone is insufficient when resin particles adhere to the mold. It takes up a large part of my working time.

In particular, if the debris in the air vent area is not removed, it will prevent the molten resin from flowing in during the next molding process, resulting in a molded product with poor appearance.

To explain this situation with reference to FIGS. 1 to 3, in a normal state (FIG. 1), the molten resin 5 passes through the runner 3 → gate 4 and enters the cavity formed by the upper mold 1 and the lower mold 2. 6
The air flows in and escapes from the air vent 7 provided on the parting surface 8, yielding a molded product 10 (inside the cavity on the left side of FIG. 2).

However, resin burr 9 from the previous shot was air vent 7.
If the resin 5 remains in the cavity, the flow of the resin 5 into the cavity 6 connected thereto is obstructed, resulting in a molded defective product 10' (inside the cavity on the right side of FIG. 2).

Therefore, it is necessary to ensure that the resin burrs on the air vent portion 7 are completely removed.

However, in cases such as semiconductor component molding, where the number of molded products is large and the molds are multi-cavity, it is difficult to ensure complete removal of debris from each air vent, and these operations are complicated. There was a problem in that the yield rate of molded products was affected.

Furthermore, these techniques, which rely on the molding operator's work such as application of an external mold release agent and deburring work, have a major drawback in that the molding itself cannot be automated.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to facilitate the peeling of resin burrs from the mold surface without using an external mold release agent, and to provide thermosetting resin without deteriorating the dimensional accuracy of the mold. To provide a mold that eliminates work time for mold cleaning in molding and enables automation thereof.

The features of this invention include, for example, the Teflock processing developed by Forestec Plating and Manufacturing Co., Ltd. of the United States, or the Teflon particle-dispersed Kanigen plating developed by Garry R. Perkins Court All Products Co., Ltd. of the United States. Alternatively, a process that disperses and composites a fluorine-containing polymer such as tetrafluoroethylene resin in a metal matrix, such as the Nidax process developed by Magnaplate of the United States, can be used to create a mold without deteriorating the dimensional accuracy of the mold. The purpose is to completely remove resin burrs and automate molding by applying it to the entire surface, parting surface, or only the air vent area, and using only an air knife and a mold auto-cleaning mechanism that uses vacuum operation.

Hereinafter, the present invention will be explained by examples.

Example 1 Only the air vent portion of the mold was treated with Teflock manufactured by Forestik Prey Rag & Manufacturing Co., Ltd. of the United States.

This Teflon processing is approximately 50 μm as shown in Figure 5a.
It consists of a step of physically and chemically creating fine cracks and pitting corrosion in the hard chrome plating layer 11, and then pressing and inserting the tetrafluoroethylene resin 12 into the cracks and holes to integrate the composite.

This process creates a surface that combines the non-stick properties of tetrafluoroethylene with the hardness of hard chrome plating.

However, since hard chrome plating is electrolytic plating,
If the film was processed with a film thickness of 50 μm, the film would become thicker at the edge portions where the electric field strength is stronger and the dimensional accuracy would deteriorate, so the mold processing method shown in FIG. 4 was adopted.

This will be explained below based on FIG.

The steel material of the cavity part of the mold is ground to a predetermined size only for the air vent part 7 (FIG. 4a).

Thereafter, leaving only the air vent portion 7 and masking the rest, hard chrome plating of approximately 50 μm is applied (Fig. 4b), and Teflock processing is performed (Fig. 4C).

By this processing, the film thickness of 50μ obtained by chromium plating is reduced by about 5μ.

Flatness has been lost due to the swell of plating on the edges.

After that, the cavity part 6 is formed by electrical discharge machining.
d), the plane part is ground to a predetermined depth of air vent to form an air vent with a depth h, and the gate part 4 is processed (FIG. 4 e).

Then, the air vent part 7 is masked, and the cavity part 6 and the flat part are plated with a thin hard chrome of about 5 μm.
A completed cavity block is obtained (Figure 4f).

The cavity block obtained in this way was attached to a molding machine and tested by molding it with epoxy resin with strong adhesive strength without using an external mold release agent. As a result, most of the resin debris generated in the air vent area was attached to the molded product. It was confirmed that the resin burrs were removed from the mold surface at the same time as the molded product was released from the mold, and that resin burrs that had broken off and remained on the mold surface could be easily and completely removed using an automatic cleaning mechanism using only an air knife and vacuum operation.

In particular, in this example, since it is a hard chrome plating layer, oxidation is prevented even when used for a long time, and resin bag removal does not change over time, which is excellent in terms of reliability.

Example 2 A Teflon particle-dispersed Kanigen plating developed by Garry R. Perkins Court All Products Co., Ltd. of the United States was applied to the entire surface of the flat surface, cavity, and air vent of a mold cavity block.

That is, as shown in FIG. 5, a Kanigen plating layer B in which Teflon particles 14 were dispersed was formed, and these were integrated into a composite.

This surface treatment method is a treatment method in which Teflon (tetrafluoroethylene resin, trade name of DuPont, USA) particles are dispersed in a nickel-phosphorous alloy electroless plating solution, and metal mah IJ lux is eutectoid.

Although the Teflon part deteriorates slightly due to heat treatment, the surface hardness increases, resulting in a surface that combines the non-adhesiveness of Teflon and the high hardness of metal Maru-'J Lux.

The cavity block thus obtained was attached to a malting machine, and a molding experiment was conducted using epoxy resin without using an external mold release agent. As a result, similar to Example 1, good results were obtained.

Example 3 Nidax treatment developed by Magna Plate, Inc. of the United States was applied to the entire surface of the flat surface, cavity and air vent of the cavity block of the mold.

This treatment method consists of forming a porous nickel alloy plating layer 11', and then impregnating the fine pores with fluororesin 12' to integrate the composite, creating a surface that has both non-adhesiveness and high hardness. becomes.

The cavity block thus obtained was attached to a molding machine, and a molding experiment was conducted using epoxy resin without using an external mold release agent. As a result, similar to Example 1, good results were obtained.

As described in detail above, according to the present invention, resin burrs can be easily removed without applying an external mold release agent, which was conventionally used to facilitate the removal of resin burrs from the air vent part. The mold auto-cleaning mechanism, which uses only an air knife and a vacuum mechanism, allows continuous molding with high yields.

In addition, even when the automatic mold cleaning device is not used, it eliminates the time required by molding workers to apply external mold release agents, check for residual deformation, and manually remove deformation, which take up a large portion of molding work. be able to.

Furthermore, defects in the appearance of molded products due to oversight of remaining paris can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of the mold, and FIGS. 2 and 3 are diagrams illustrating the situation in which defective molded products are produced when resin burrs are formed. −■ Cross-sectional view,
FIG. 3 is a plan view showing the lower die. Fig. 4 is a process diagram showing the process of partially applying Teflock to only the air vent portion 7, and Fig. 5 is a process diagram showing the process of embedding or impregnating a fluororesin into a metal base made of hard chrome plating or nickel alloy plating. FIG. 2 is a cross-sectional view showing a state in which the particles are dispersed, eutectoided, and integrated into a composite structure. 1...Top mold, 2...Bottom mold, 7...
...Air vent, 9...Resin burr on the air vent part.

Claims (1)

[Scope of Claims] 1. In a thermosetting resin molding die, a fluororesin is applied to a metal matrix such as hard chrome plating or nickel alloy plating on the parting surfaces of the upper mold and the lower mold, and is connected to the cavity. A mold for molding thermosetting resin characterized by an air vent with a surface treatment. 2. In a thermosetting resin mold, fluororesin is pressed and bonded into the fine cracks and holes formed in the hard chrome plating layer, connected to the cavity and on the parting surfaces of the upper and lower molds. A thermosetting resin molding die characterized by having an air vent inserted and integrated into a composite body and subjected to surface treatment.