JP2001335340A - Mold to form glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the high temperature durability of a mold for forming glass and mold-releasing performance of glass easily and at low cost. SOLUTION: A single layer film composed of TiAlN is formed on the surface of a mold for forming glass by vacuum depositing, sputtering, or ion plating Ti, Al and N at the same time. Since the single layer film composed of TiAlN has excellent high temperature durability and mold-releasing performance, the mold for forming glass is improved in these characteristics. Further, since the single layer film is formed by only one physical vacuum deposition process and does not need any treatment such as grinding after deposition, film formation can be performed inexpensively and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a glass forming mold for forming glass bottles, glass tableware, glass disks for magnetic storage media, glass covers for meters, glass products for home appliances, and the like.

[0002]

2. Description of the Related Art Conventionally, a base material of a glass forming mold is generally cast iron, low-carbon steel, stainless steel, or the like, and a surface thereof is coated with a release material. It has also been proposed to form a protective film such as titanium nitride (TiN) on the surface of a base material. A method of laminating a plurality of protective films has also been proposed.

[0003]

A mold base material such as cast iron, low carbon steel, and stainless steel is characterized in that it easily adheres to glass at high temperatures. Therefore, the conventional mold having no protective film on the surface has the following problems.
Since the mold temperature cannot be raised too high, the moldability is poor, and there is a high possibility that defective moldings will occur. Since the releasability of the glass is poor, a machine trouble at the time of the release and a bad skin of the glass product easily occur. The use of a release agent improves release properties,
New skin problems due to the release agent are likely to occur. further,
Due to the low heat resistance (high-temperature hardness) of these base materials, the surface of the mold surface (the part of the mold that is formed in direct contact with the glass) is likely to be roughened, and the mold is frequently replaced due to poor durability. There is a problem that must be done. Base materials such as silicon carbide, cemented carbide, and silicon nitride have higher high-temperature hardness than the above-mentioned general base materials, but are extremely expensive and are used only in special cases.

It has been proposed to form a protective film such as titanium nitride (TiN) on the surface of the base material in order to improve the releasability and heat resistance of the base material, but the effect is insufficient. It is something. Although a method of laminating a plurality of protective films has been proposed, it is not practical because the manufacturing process is complicated and the cost is high.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the high-temperature durability of a glass molding die and the releasability of glass easily and inexpensively.

[0006]

SUMMARY OF THE INVENTION The present invention provides Ti, Al,
A glass forming mold characterized by having a single layer film of TiAlN formed on the surface by simultaneously performing vacuum deposition, sputtering or ion plating of N on the surface.

[0007] The single layer film of TiAlN is very excellent in heat resistance and releasability. For this reason, inexpensive cast iron, low carbon steel, stainless steel, and the like are sufficient for the base material of the mold, and a glass product with a beautiful surface finish can be formed stably. In addition, since the durability at a high temperature is good, the mold exchange time can be extended three times or more as compared with a conventional product (one without a protective film), and there is no machine trouble at the time of glass release.

Further, since the present invention forms a single-layer film on the surface of the mold, only one physical vapor deposition step is required, and no treatment such as polishing after vapor deposition is required. The film can be formed easily and inexpensively. The thickness is preferably about 3 to 5 μm.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 4 are explanatory views of general press molding (block mold press). This mold has a body mold 1, a ring mold 2, and a plunger 3. FIG. 1 shows a state in which the gob 4 is supplied into the body mold 1, FIG.
3 shows a state in which the ring mold 2 is lowered and fitted on the body mold 1, FIG. 3 shows a state in which the plunger 3 is lowered and press-formed, and FIG. 4 shows a state in which the ring mold 2 and the plunger 3 are raised. This shows a state in which press molding of the glass product 5 has been completed.

In the case of the molds shown in FIGS. 1 to 4, vacuum deposition is performed on the appearance surface (inner surface) 1a of the body mold 1 and the tip 3a of the plunger 3.
Ti by sputtering or ion plating
A single layer film of AlN is formed. Vacuum deposition, sputtering, and ion plating are well-known physical film forming methods. Here, the film formation by an arc plasma ion plating method will be described. An evaporation source (target) of the Ti-Al alloy is applied negatively to cause arc discharge on the surface. This arc discharge melts Ti and Al from an arc spot on the target surface, and evaporates at a Ti / Al ratio corresponding to a predetermined vapor pressure. These evaporated metals are ionized in the plasma region created by the arc discharge. At the same time, nitrogen gas introduced into the apparatus is similarly ionized and becomes nitrogen ions. On the other hand, a negative voltage is applied to the mold (work) to be coated. As a result, a large potential gradient is generated between the ions and the mold, and high-energy titanium ions, aluminum ions, and nitrogen ions collide with the mold surface, forming a diffusion layer partially inside, and forming a diffusion layer on the surface. TiA with good adhesion
An 1N single layer film is formed.

The TiAlN single layer film has extremely high heat resistance, and as a guideline, the thermal oxidation was measured as the temperature increased. As a result, when the temperature of titanium nitride (TiN) exceeded 450 ° C., the thermal oxidation rapidly progressed. , TiAlN single layer film is 75
Almost no thermal oxidation progresses up to 0 ° C. Accordingly, the mold can be used at a high temperature, the glass can be molded in a state of glass having excellent fluidity, a glass product having good dimensional accuracy and a beautiful surface finish can be molded, and the mold replacement time is prolonged.

Further, the TiAlN single layer film is excellent in the releasability of glass. Comparing the glass adhesion temperature (the temperature at which the mold adheres when the temperature of the mold is raised) to the base metal, the TiAlN single layer film is 750 ° C, the FCD (ductile cast iron) is 670 ° C, and the SUS material (Stainless steel) is 620 ° C
It is. Therefore, the mold of the invention has good glass releasability even when used at a high temperature, and has disadvantages (cracks, etc.) upon release.
Can be prevented. Since the amount of the release agent used can be reduced, the occurrence of bad skin of the glass product is also reduced.

An inner surface 1a of a cast iron body mold 1 shown in FIGS.
The tip 3a of the plunger 3 was mirror-polished by buffing the surface, and a single-layer film of TiAlN was formed thereon by ion plating. The surface roughness of the film is 8
The mirror surface was less than 00 °. When a glass product was press-molded using this mold, a glass product having a similar mirror-like surface could be obtained. When this mold was used continuously, the mold replacement time due to the occurrence of bad skin on the surface of the glass product could be extended three times or more. In addition, the process was stable because of good releasability.

Although the embodiment has described the press molding,
The present invention can be similarly applied to blow molding dies such as glass bottles.

[0015]

According to the present invention, a press-molding mold for molding glass tableware and the like uses a mirror-finished mold as much as possible to improve the skin of the product (to prevent wrinkles and streaks caused by gobroding). It is common practice to work at elevated temperatures, but this will tend to cause the adhesion of the glass to the mold, making the process unstable. By using the mold of the present invention, the temperature of the mold can be raised to form a glass product, and a glass product with good skin can be stably produced. Furthermore, when the mold temperature is increased, the mold surface deteriorates faster and the mold life is shortened.However, by using the mold of the present invention, the mold replacement frequency is reduced, and the productivity is also reduced. Can be improved.

In the press forming of a glass disk for a magnetic storage medium, it is preferable that the thickness of the blank material be as small as possible in order to reduce the polishing allowance due to lapping or the like. Therefore, the temperature of the mold should be as high as possible, but then the release of the glass will be poor (because the adhesiveness of the glass will increase),
The process becomes unstable. In order to prevent this, the surface of the mold is generally roughened by a honing treatment or the like in advance (to improve the release), but the glass surface also becomes ground glass. Although it is difficult to find glass defects such as bubbles and foreign matter in the blank in that state, if the glass surface is in a mirror surface state, it becomes possible, and the yield after polishing can be increased. By using the mold of the present invention, it is possible to mold a mirror-finished blank at the same mold temperature as that of the conventional mold subjected to the honing treatment.

In molding glass products, if the releasability is poor,
When the glass product is taken out of the mold (when the mold is opened in the split mold), the glass surface is pulled and defects such as cracks occur. Since the mold of the present invention has good mold release properties at high temperatures, the occurrence of these defects can be prevented. Since the amount of the release agent used can be reduced, the occurrence of bad skin of the glass product is also reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of forming a glass product by a block mold press.

FIG. 2 is an explanatory diagram of molding of a glass product by a block mold press.

FIG. 3 is an explanatory view of forming a glass product by a block mold press.

FIG. 4 is an explanatory diagram of molding of a glass product by a block mold press.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body type 2 Ring mold 3 Plunger 4 Gob 5 Glassware

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 14/34 C23C 14/34 CF Term (Reference) 4G015 HA01 4K029 AA02 BA58 BC00 BD00 CA04 DB04 DD06

Claims (1)

[Claims] 1. A glass-forming mold having a single-layer film of TiAlN formed on the surface by simultaneous vacuum evaporation, sputtering or ion plating of Ti, Al, and N.