JPH03243786A - Production of metallic mold - Google Patents

Abstract

PURPOSE:To uniformly form a ceramic film on the deep groove, etc., of a metallic mold at the time of forming the ceramic film on the recessed forming surface of the mold by forming the ceramic film on the projecting surface of a master pattern, forming a backup shell thereon and then removing the pattern by dissolution so as to incorporate into the concave part of the mold. CONSTITUTION:A high-hardness and smooth ceramic film of TiC, TiN, etc., low in frictional force is formed on the forming surface of a metallic mold having a deep groove and a hole. In this case, a master pattern 1 having the protrusions 11 and 12 corresponding to the recessed part of the metallic mold 4 consisting of a hole 51 and a groove 52 is formed with Al. A hard ceramic film 2 of TiN, TiC, etc., is vapor-deposited on the surface by ion plating, etc., Ti and Ni are further deposited thereon, a backup shell 3 of Ni is electrocast, the Al pattern 1 is dissolved in aq. sodium hydroxide and removed, and the shell 3 is cut to a specified size and incorporated into the metallic mold main body 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for using a mold having a concave molding surface.

[Prior art and its problems]

For example, Ti is applied to the molding surface of a synthetic resin injection mold.
When ceramic coatings such as C or TiN are deposited using PVD (physical vapor deposition) treatment such as ion plating, these ceramic coatings have extremely high hardness and smooth surfaces, so frictional force and mold release force are small. This reduces the damage rate of molded products during mold release and shortens cycle time. In addition, the occurrence of deposits released from the melt in the mold is reduced, and there is no need to remove deposits, reducing downtime. Furthermore, since the melt flow within the mold becomes longer, pressure loss, uneven temperature distribution, uneven wall thickness, etc. are alleviated, reducing molding defects, and corrosion resistance against hot gas is also greatly improved. .

When a ceramic film is deposited on a press mold, cold welding and adhesive wear are also reduced, which slows down the surface shedding after microcracks occur, making it possible to process the product for the first time by depositing a ceramic film. There are many cases where this has happened.

By the way, in PvD processing such as the ion plating method, a sufficient magnetic field is not formed in the deep grooves of the processed product, the inner surfaces of the holes, or the bottom surfaces of the holes, so it is difficult for ions to reach these parts, making it difficult to secure the required film thickness. There are problems in that it is difficult to adhere and the adhesion is not sufficient. Therefore, when a ceramic film is deposited on the molding surface of a mold (matrix) with a concave molding surface, it is difficult to coat the deep grooves and inner surfaces of holes, and the above advantages cannot be fully obtained. For.

The mold is made into a split mold to eliminate deep grooves and holes before vapor deposition, or CVD (chemical vapor deposition) is used to deposit the mold, but split molds increase the cost of the mold, and CVD processing also reduces the cost of the treated product. It requires heating to high temperatures and is only used in special cases.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a mold in which the deep grooves and inner surfaces of holes of a mold having a concave molding surface are sufficiently coated with a ceramic film.

[Structure of the invention and its effects]

The mold manufacturing method of the present invention includes a step of depositing a ceramic film on the surface of a convex master pattern using a PVD process such as ion plating, and forming a backup shell on the ceramic film using an electroforming method or the like. The method is characterized by comprising a step of removing the master pattern from the ceramic film to which the backup shell is adhered, and a step of incorporating the backup shell into the recess of the mold body.

That is, a master pattern for a mold with a concave molding surface is convex, and the portions corresponding to the deep grooves and holes of the mold become ridges and protrusions. Therefore, the entire surface of the master pattern can be uniformly coated with a ceramic film by PVD treatment such as ion plating. Then, after the backup shell is brought into close contact with this ceramic film and the master pattern is removed, the backup shell is incorporated into the recessed part of the mold body, so the ceramic film is evenly coated on the deep grooves and inner surfaces of the holes in the completed mold. has been done.

〔Example〕

The present invention will be specifically described below based on embodiments shown in the drawings.

(1) Master pattern As shown in FIG. 1(A), the master pattern 1 made of aluminum has a protrusion 11 corresponding to the deep hole of the mold with a concave molding surface and an annular protrusion corresponding to the groove of the mold. 12 is formed and has a convex shape as a whole.

(2) Vapor deposition of ceramic film As shown in FIG. 1(B), ceramic film 2 was vapor-deposited on the surface of this master pattern using an arc discharge type ion plating apparatus under the following conditions.

Substrate voltage: 50V Ionization voltage: 45V Ionization current: 70A Substrate temperature: 200°C Vacuum degree: 5 x 10-'Torr Nitrogen gas was introduced under the following conditions to 135 m1n.

During the treatment, a TiN film having a thickness of about 3 μm is uniformly deposited on the entire surface of the master pattern 1. The ceramic film 2 is not limited to TiN, and in addition to TiC and T1CN, Z
Nitride, carbide, oxide, etc. of metals such as r, Hf, Nb, W, Ta, and V, and their alloys can be used.

In this embodiment, the backup shell 3 to be explained next is N
Since it is formed by the electroforming method of i, TiN is used to improve the adhesion between the ceramic film 2 and the backup shell 3.
Ti is vapor-deposited on top of it, and Ni is further vapor-deposited on top of it.

In other words, by gradually reducing the amount of nitrogen gas introduced,
When n is set to zero, TiN decreases and Ti gradually increases, and in the next 10+ inches, a film consisting only of Ti is formed. Then, in the next Login, Ti and Ni,
Deposited so that Ti decreases and Ni gradually increases,
Only Ni is evaporated in the last 10+ inches, and the outermost layer is covered with Ni.
Make it into a film.

Note that the method for depositing the ceramic film 2 is not limited to the ion plating method, and may be performed by a PvD process such as a vacuum deposition method, a sputtering method, or a laser physical vapor deposition method.

(3) Formation of backup shell After electroforming for 240 hours under the following conditions, a backup shell 3 made of Ni with a thickness of about 12 mm is formed and adheres closely to the ceramic coating 2, as shown in Figure 1 (C). .

Nickel sulfamate 300 g / Q Nickel hydrochloride 30 g / Q Boric acid 40 g / Q pH 4,0 Bath temperature 50°C Current density 8 A/d The method for forming the back-up shell 3 is not limited to electroforming, but also thermal spraying. , a pressing method such as HIP or SIP, or a hard resin.

(4) When immersing the master pattern in sodium hydroxide (30g/R) in the removal and assembly machine,
The master pattern 1 made of aluminum is melted and removed, leaving the backup shell 3 to which the ceramic skin 11512 is adhered. Then, the outer periphery is removed to a predetermined size to create the state shown in FIG. 1(D).

When this is assembled into the recess of the mold body 4 as shown in FIG. 1(E), the mold is completed. Note that the outer periphery of the backup shell 3 may be removed to a predetermined size, the master pattern 1 may be removed, and then the back-up shell 3 may be incorporated into the recessed portion of the mold body 4.

In this way, since the ceramic film 2 is uniformly formed on the master pattern 1, a uniform ceramic film 2 is also formed on the surfaces of the deep holes 51 and grooves 52 of the completed mold.
It is possible to create a mold with an extremely hard molding surface.

〔Effect of the invention〕

As explained above, the mold manufacturing method of the present invention involves depositing a ceramic film on the surface of a convex master pattern using a PVD process such as ion plating, bringing a backup shell into close contact with this ceramic film, and After removing the pattern, the backup shell is incorporated into the concave part of the mold body, so it is possible to uniformly form a ceramic coating even on the deep grooves and inner surfaces of holes in the mold, which has a concave molding surface.

[Brief explanation of drawings]

FIGS. 1(A) to 1(E) are process explanatory diagrams of an embodiment of the present invention. 1... Master pattern 2... Ceramic film 3... Backup shell 4... Mold body Figure i (C)

Claims (1)

[Claims] A step of depositing a ceramic film on the surface of a convex master pattern by a PVD process such as an ion plating method, and a step of forming a backup shell on the ceramic film by an electroforming method or the like. A method for manufacturing a mold, comprising the steps of: removing a master pattern from a ceramic film to which a backup shell is adhered; and incorporating the backup shell into a recess of a mold body.