KR101782344B1

KR101782344B1 - Molds for plastic injection molding

Info

Publication number: KR101782344B1
Application number: KR1020160020413A
Authority: KR
Inventors: 허정
Original assignee: (주)국민진공
Priority date: 2016-02-22
Filing date: 2016-02-22
Publication date: 2017-09-27
Also published as: KR20170098473A

Abstract

The present invention relates to a mold for injection molding of synthetic resin which is easy to mold a high strength engineering plastic.
The mold for synthetic resin injection molding according to the present invention is manufactured by coating a target material by vacuum evaporation on the surface of a mold for forming a mold for injection molding of a conventional synthetic resin injection molding under the conditions of a temperature of 200 ± 50 ° C. The vacuum deposition is performed by depositing the target material for 10 ± 5 minutes at a voltage of 400 ± 50 V and resting for 3 ± 2 minutes for a total of 30 ± 20 minutes to deposit the target material The target material was deposited for a total of 150 ± 50 minutes in such a manner that the target material was deposited for 10 ± 5 minutes at a voltage of 200 ± 50 V and then rested for 3 ± 2 minutes to form a second coating layer, And is completed.

Description

Technical Field [0001] The present invention relates to a mold for plastic injection molding,

The present invention relates to a mold for injection molding of synthetic resin which is easy to mold a high strength engineering plastic.

Injection molding of a synthetic resin is performed by filling a molten resin into a cavity of a mold having a desired shape of the product, and cooling the resultant to mold it in a form of hardening. The mold used here is easy to peel off the molded product from the cavity, The cavity surface roughness of the mold must be fairly precise to smooth the roughness.

In order to improve the above accuracy, it is the most common practice to precisely mold the cavity of the mold by a machine tool. Further, the surface of the mold is heat treated before or after the process, or the plating process is performed.

However, in recent years, due to the development of high-strength synthetic resins such as polyphenylene sulfide (PPS), which is one of the super engineering plastic types that can replace metals, the synthetic resin to be injection-molded gradually changes to stronger strength to be.

When the above-described high-strength synthetic resin is handled in a mold manufactured by a conventional method, the following problems are caused.

First, in the case of an injection mold finished by machining and heat treatment, since there is a limit in smoothly forming the surface roughness due to the characteristics of machining and heat treatment means, the surface roughness of the hardened finished product is considerably coarse, It is difficult to extract the finished product from the cavity by the friction which combines the strength of the synthetic resin and there is a problem that scratches are generated when extracting due to the low hardness of the surface.

In the case of an injection mold finished by plating on the surface of a mold after machining and heat treatment, the surface roughness of the finished product can be guaranteed to some extent. However, when the finished product is extracted from the cavity by the strength of the synthetic resin There is a problem that the plating is peeled off due to the frictional force generated.

Therefore, in the case of handling a high-strength synthetic resin, a mold manufactured by a conventional method has problems in ensuring surface roughness for a hardened product, assuring ease of extraction from the cavity, and maintaining the surface of the cavity constantly have.

Meanwhile, in order to solve the above-mentioned problem, recently, a method of vacuum depositing a target material on the surface of an injection mold by an arc ion plating technique has been tried in the same manner as applied to a press mold.

However, since the above-described vacuum deposition method must be performed at a high temperature of 500 degrees or more, thermal deformation of the mold is caused in the process, and accuracy of the injection molding is lowered.

delete

Published patent application No. 10-2012-0139458.

As described in the Background of the Invention, when manufacturing a mold for injection molding of a synthetic resin, it is possible to ensure smooth surface roughness of a finished product when handling a high-strength synthetic resin, to facilitate extraction from the cavity, The present invention aims to provide a mold for injection molding of synthetic resin which can be maintained continuously.

As a means for achieving the above object, the present invention provides a mold for injection molding of a synthetic resin, wherein the surface of the mold is coated with a target material by vacuum evaporation, and the vacuum evaporation is performed at a temperature of 200 ± 50 ° C The vacuum deposition is performed by depositing the target material for 10 ± 5 minutes at a voltage of 400 ± 50 V and resting for 3 ± 2 minutes for a total of 30 ± 20 minutes to deposit the target material The target material was deposited for a total of 150 ± 50 minutes in such a manner that the target material was deposited for 10 ± 5 minutes at a voltage of 200 ± 50 V and then rested for 3 ± 2 minutes to form a second coating layer, To complete the process.

According to the above-described means, the target material is uniformly deposited in the roughness of the surface layer by the increase of the ion energy due to the high voltage, the activation of the discharge by the high voltage, and the relaxation thereof so that the adhesion between the target material and the surface layer is ensured, The bonding force between the deposition materials is enhanced to enhance the surface hardness, and the surface roughness can be made highly smooth. This makes it possible to ensure a smooth surface roughness of the finished product by the surface roughness when handling the high strength synthetic resin mentioned in the solution, and to easily extract the finished product from the cavity by low friction, and the surface of the cavity is continuously So that it can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.
Fig. 2 is an exemplary view of a vacuum deposition apparatus applied to Fig. 1
Fig. 3 is an exemplary view of an injection mold completed by Fig. 1

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the appended drawings may be exaggerated, omitted, or outlined for convenience of description, and the terms and names used in the description are intended to be implicitly construed according to the shape, And the description of the position will be described with reference to the drawings unless otherwise specified. And specific descriptions of well-known and commonly-used techniques may be omitted to avoid obscuring the subject matter, or to be omitted or replaced with a simple code or name.

Hereinafter, the configuration of the present invention will be described.

As described in the solution, the present invention relates to a method of manufacturing a mold for injection molding of a synthetic resin by coating the surface of the mold with a target material by vacuum evaporation so that the temperature of the vacuum deposition is maintained at 200 ± 50 ° C The vacuum deposition is performed by depositing the target material for a total of 30 ± 20 minutes in a manner of resting for 3 ± 2 minutes after depositing the target material for 10 ± 5 minutes at a voltage of 400 ± 50 V, The target material is deposited for a total of 150 ± 50 minutes in such a manner that the target material is deposited for 10 ± 5 minutes at a voltage of 200 ± 50 V second and then rested for 3 ± 2 minutes to form a second coating layer And finished.

Hereinafter, a configuration that can be added, deleted, or limited in the present invention will be described.

The above-described mold for injection molding of a synthetic resin can be performed by eliminating the first coating layer forming step which is performed first, and instead, by increasing the total time taken for forming the second coating layer, which is performed secondarily, for a total of 200 minutes.

Before the deposition of the target material, the metal mold for injection molding of synthetic resin is cleaned with argon (Ar) on the surface of the mold for 20 minutes at a voltage of 700 V, metal cleaning for 20 minutes at a voltage of 600 V, (Ar) cleaning, and a second metal (Metal) cleaning.

The vacuum deposition method may be performed by any one of Arc Ion Plating (AIP), Unbalanced Magnetron Sputtering (UBMS), and Plasma Enhanced Chemical Vapor Deposition (PECVD) .

In addition, the above-mentioned target material may include one or a combination of two or more of a nitride and a carbide which can be deposited.

The above-mentioned nitride is performed by any one or a combination of two or more of Cr, Al, and Ti, and the carbide may be at least one selected from the group consisting of B ₆ C, SiC, TiC, ZrC, ThC ₂ , V ₅ C, V ₄ C ₃ , NbC, TaC, or a combination of two or more.

Below, 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In an embodiment,

A sample chamber A2 (chamber A2) in a chamber A1 of a vacuum evaporation apparatus provided with a sample stage A2, a vacuum outlet A3, a heater A4, a gas inlet A5 and a plurality of targets A6 is provided in the chamber A1. ), The injection mold (a) corresponding to the object to be deposited is placed on the upper surface,

The inside of the chamber A1 is evacuated by the vacuum exhaust port A3 and the inside temperature of the chamber A1 is maintained at a maximum of 200 ° C by using the heater A4,

A positive voltage is applied to the chamber A1 and a positive voltage is applied to the chamber A1 at 700 V while argon (Ar) gas is injected into the chamber A1 by using the gas injection port A5 in the first stage, The surface was subjected to an argon rinse for 20 minutes,

A negative voltage is applied to the chamber A1 and a positive voltage is applied to the chamber A1 at a voltage of 600 V to discharge the argon (Ar) gas in the chamber A1 by using the second vacuum exhaust port A3, The surface was metal cleaned for 20 minutes,

A negative voltage was applied to the specimen stage (A2) at the third time, a positive voltage was applied to the target (A6) at 400 V, the target material was deposited for 10 minutes, and then the target material was deposited for about 30 minutes by resting for 3 minutes, After the coating layer (b1) is formed,

The target material was deposited for about 150 minutes by applying a negative voltage to the sample stage (A2) and a positive voltage to the target sample (A6) at 200V for 10 minutes and then resting for 3 minutes to deposit the target material The coating layer b2 was formed to complete the final injection mold.

Hereinafter, the operation and effect of each step will be described as follows.

The argon cleaning, which is carried out primarily in the above, is carried out in order to equalize the irregular surface roughness by scraping the surface of the injection mold by electrical discharge by plasma. The above-described argon cleaning can shorten the time of the metal cleaning performed secondarily, advantageously makes it possible to deposit the target material to be performed in the third and fourth order, and improve the surface texture of the final coating layer to a high level It can be done evenly. Although the above-described argon cleaning may not be carried out if necessary, it is necessary to increase the time for the metal cleaning to be performed secondarily, and the deposition of the target material to be performed in the third and fourth order is disadvantageous, It is possible to cause a problem that the texture of the surface to the surface can not be made highly uniform.

The metal cleaning, which is performed in the second step above, is carried out in order to more precisely shave the surface of the injection mold by electric discharge by voltage, thereby making irregular surface roughness more uniform. When the metal cleaning is performed as described above, deposition of the target material to be performed in the third and fourth order is further advantageous, and the surface texture of the final coating layer can be made extremely high. The above-described metal cleaning may not be carried out if necessary. However, the deposition of the target material to be performed in the third and fourth order is disadvantageous, and the texture of the surface of the final coating layer can not be made highly uniform .

On the other hand, although the argon cleaning and the metal cleaning described above may not be carried out if necessary, the deposition of the target material to be performed in the third and fourth order is considerably disadvantageous and the surface texture of the final coating layer It can cause problems that can not be made even. Therefore, it is most preferable to perform the primary argon cleaning and the secondary metal cleaning, and if not, it is preferable to perform only the secondary metal cleaning.

The deposition of the target material, which is performed in the third step above, is performed by applying a high voltage of 400V compared with a conventional method of applying the arc ion plating technique at a voltage of 80V for 180 minutes.

When the deposition is performed in such a state that the high voltage is applied, an increase of the ion energy due to the high voltage and activation of the discharge by the high voltage causes the target material to be uniformly deposited in the roughness of the surface layer and the adhesion between the target material and the surface layer And the bonding force between the deposition materials can be enhanced to enhance the surface hardness, and the surface roughness can be made highly smooth.

This is due to the deposition of the target material at 500 &

It is possible to solve the problem that can not be applied to a precision mold because the thermal deformation of the mold is caused and the degree of the injection molding is lowered and the target material is deposited on the surface layer by a method of depositing the target material at a low voltage, It can not be densely deposited on the roughness gap, so that the adhesiveness is lowered and the bonding between the deposition materials is weak, so that the problem of the hardness and surface roughness being lowered can be overcome.

On the other hand, the reason for going through a rest for 3 minutes is that if the deposition process is performed for a long time under a high voltage, the target material deposited in the roughness of the surface layer by deposition of the internal stress can be separated from the roughness of the surface layer . This results in a problem that the final coating layer is not bonded integrally with the surface layer and is liable to separate and peel off. In order to overcome this, a rest is placed in the middle, and when the material is rested, the target material which is deposited in the roughness of the surface layer and deposited is integrated with the roughness of the surface layer. Thereafter, when the discharge is started again, the target material is gathered again into the roughness of the surface layer where the target material is integrated, and a new surface layer is formed.

Thus, a rest period can result in an increase in the bonding force between the target material and the surface layer, an increase in the bonding force between the target materials, and an increase in the thickness of the coating layer in a repetitive manner.

The deposition of the target material, which is performed in the fourth step above, is performed in order to make a more precisely deposited coating layer on the surface of the thirdarily deposited coating layer, such as the metal cleaning performed secondarily. For this purpose, the voltage is lowered from 400V to 200V, and the deposition time is prolonged.

The above deposition method was performed by an arc ion plating method, and a target material was made of Cr to form a coating layer of a chromium nitride layer (CrN). At this time, the coating layer of the final injection mold was measured to have a hardness of Hv 2200 or more and an adhesion of 33 N or more. These values correspond to values that can not be achieved with conventional deposition methods below 500 ° C. Using this completed injection mold, polyphenylene sulfide (PPS), one of the super engineering plastic types, is applied As a result, it was confirmed that smooth surface texture was ensured, extraction from the cavity was easy by low friction, and the surface of the coated cavity was not peeled off or torn even if it was used for a long time.

In the above embodiment, as described in the configuration of the present invention, the set temperature, the applied voltage, the deposition time of the target material, the total deposition time, and the like can be changed flexibly according to the properties of the molding to be molded.

Hereinafter, an application of the embodiment will be described.

As an application of the embodiment, in the above-described embodiments, as described in the constitution of the present invention, the primary argon cleaning and the secondary metal cleaning can be selectively applied, and the step of forming the first coating layer can be selectively applied , The vacuum deposition method may be carried out by changing or mixing with the unbalance magnetron sputtering or the plasma chemical vapor deposition in the arc ion plating, and the target material may also be changed or mixed with the above target.

Hereinafter, the application of the above-described configuration will be described.

It is most preferable that the present invention includes all of the above-described configurations, but it is possible to select only some of the configurations described above according to cost reduction, manufacturing convenience, or need. In addition, each of the above-described configurations may be independently applied to a technical field other than the technical field in consideration of the purpose, function, role, action, and the like. Based on this, the present invention can be variously specified as follows.

It will thus be appreciated by those skilled in the art that the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment of the invention, Will be possible.

A1: chamber A2: sample stand
A3: Vacuum exhaust A4: Heater
A5: Gas inlet A6: Target
a: injection mold b1: first coating layer
b2: Second coating layer

Claims

The target material is coated with Cr, Al, Ti, B ₆ C, SiC, TiC, ZrC, or the like by vacuum deposition using a arc ion plating technique in the production of a mold for injection molding of a synthetic resin injection molding. , ThC2, V ₅ C, V ₄ C _3, NbC, TaC of any, and one or performing a vacuum deposition in combination of two or more, the conditions of the vacuum vapor deposition of the target material is in a state to maintain the temperature of 200 ± 50 ℃ The vacuum deposition was performed by depositing the target material for a total of 30 ± 20 minutes by depositing the target material for 10 ± 5 minutes at a voltage of 400 ± 50 V and resting for 3 ± 2 minutes, After forming the coating layer, the target material is deposited for a period of 10 ± 5 minutes at a voltage of 200 ± 50 V second, followed by resting for 3 ± 2 minutes, so that the target material is deposited for a total of 150 ± 50 minutes to form a second coating layer Lt; / RTI &
Optionally, removing the forming step of the first coating layer to be carried out primarily and increasing the time taken for the forming of the second coating layer to be carried out secondarily in total instead of 200 minutes,
Before the deposition of the target material, the surface of the metal mold was cleaned with argon (Ar) at a voltage of 700 V for 20 minutes, metal was cleaned at a voltage of 600 V for 20 minutes, or primary argon (Ar) And a second metal cleaning step of cleaning the metal mold.

delete