JPH0581537B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a glass molding plunger used in a glass molding machine. (Prior art) The plunger for glass molding as above is 1000
Since the parison is formed by melting molten glass at a high temperature of .degree. C. or higher, the surface tends to become rough due to wear during use, and dimensional accuracy tends to decrease. For this purpose, as shown in FIG. 3, it has been practiced for a long time to spray a self-fluxing alloy 2, such as chromium-nickel-boron, on the entire surface of the plunger body 1 to prevent wear. However, recent research has gradually revealed the reason why the practical strength of glass bottles is extremely low compared to the theoretical strength. It has become clear that this is an essential element for increasing impact strength), and it has also become known that one of the causes of such minute cracks is the surface condition of the plunger. When a plunger coated with self-fusing alloy 2 is used as described above, the metal oxide produced when the surface of the plunger melts with high-temperature glass peels off during molding and adheres to the parison, causing the parison to blow. The metal oxide remains attached to the inner surface of the glass bottle, and when it is cooled after molding, the tensile force that acts on the glass to which the metal oxide is attached due to the difference in expansion coefficient between the glass and the metal oxide causes the metal oxide to be removed. It has become clear that cracks will grow from this point. Recently, attempts have been made to coat the entire surface of the plunger body 1 with a ceramic material 3 such as TiN, as shown in FIG. Such a ceramic coating has excellent heat resistance, so it does not cause peeling as described above, and has a high hardness of H _V 1000 or more, so it has the advantage of excellent wear resistance. However, according to research conducted by the present inventor, it has been found that glass bottles formed by such ceramic-coated plungers are susceptible to vertical scratches of several hundred microns in length on the inner surface of the mouth. Ta. As a result of analyzing this scratch, it was found that the scratch was a trace where the glass on the inner surface of the mouth was scraped off by the ceramic material 3 on the plunger surface. These scratches occur on the inner surface of the thick mouth part, so they do not directly lead to a decrease in the strength of the glass bottle, but if these scratches are large, the mouth part becomes cracked, causing damage. The reflection reduces the product value and becomes an obstacle to detecting other mouth defects. (Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and improves the strength of glass bottles, especially impact strength, without causing scratches on the inner surface of the mouth part or reducing strength due to peeled objects. It was completed to provide a glass forming plunger suitable for manufacturing high-quality glass bottles. (Means for solving the problem) The above problem was solved by coating the mouth molding part of the plunger body that molds the parison with a self-fusing alloy of H _V 800 or less, and coating the tip part with ceramic material. This problem can be solved by a plasticizer for glass forming characterized by the following. (Example) The present invention will be described in more detail below with reference to the embodiments shown in FIGS. 1 and 4. In FIG. 1, reference numeral 1 denotes a plunger body for forming a parison by being attached to a press-blow type glass forming machine, and the plunger itself is made of alloy tool steel like the conventional plunger body. In the present invention as well, the outer surface of the plunger body 1 is coated with a ceramic material 3, but the mouth molded portion is coated with a self-fusing alloy 2 having a H _{V of} 800 or less at room temperature. Here, the mouth molded part means a part slightly above the boundary line 4 between the straight part and the tapered part of the plunger body 1, but in the embodiment, it is 10 degrees above the boundary line 4.
This is the part up to about 20mm upwards. However, as is well known to those skilled in the art, the shape of the plunger varies widely depending on the shape of the parison used for molding, so it goes without saying that the range of the mouth molding section will also change accordingly. It is. In the present invention, the ceramic material 3 coating the tip of the plunger body 1 can be selected from materials with excellent heat resistance and oxidation resistance, such as TiC, TiN, TiCN, SiC, and Al ₂ O ₃ . ,
These ceramic materials 3 may be coated by a CVD method, a PVD method, or the like. These ceramic coatings generally have a hardness of H _V 1000 or more at room temperature, and can be coated with multiple layers of the above materials. Also, the plunger body 1
The self-fusing alloy 2 coated near the molded mouth part of the
A nickel-based material or a cobalt-based material with a hardness of H _V 800 or less can be used. Here, the hardness of self-fusing alloy 2 was limited to H _V 800 or less because
This is because if a coating harder than this is applied, there is a risk of scraping the inner surface of the mouth of the parison when the plunger descends after forming the parison. (Function) The plunger for glass molding of the present invention configured as described above has a mouth mold 1 as shown in FIG.
0, guide ring 11, rough mold 12, buttful 13
It is similar to the conventional plunger of this type that a parison is formed by pressing molten glass inside the cavity formed by the above method. However, in the present invention, the plunger body 1
Since the tip of the plunger is coated with Ceramic Material 3, which has excellent wear resistance, there is no possibility of peeling off due to oxidation of the surface of the plunger, and it is possible to prevent cracks caused by peeling off. It has a high hardness of H _V 1000 or more, so it has the advantage of excellent wear resistance. Moreover, in the present invention, since the mouth molded part of the plunger body 1 is coated with a self-fusing alloy 2 having H _V 800 or less at room temperature, the entire surface of the plunger body 1 is coated with a hard ceramic material 3 as in the conventional case. Unlike this, the plunger does not scrape the inner surface of the parison's mouth when descending. Therefore, the inner surface of the opening of the glass bottle obtained by blow molding this parison will not be damaged. Although the plunger of the present invention does not have a ceramic coating applied to the molded part of the mouth, the temperature of the plunger near the mouth is relatively low at 500°C or less, so metal oxides are less likely to peel off. Since the glass and wall thickness are large, there is no risk of a decrease in strength. In order to confirm the effects of the present invention explained above,
The following tests were conducted. First, the plunger of the embodiment is coated with a chromium-nickel-boron-based self-fusing alloy on the mouth-forming part, and then with TiN on the tip, and the mouth-forming part is coated with the above-mentioned self-fusing alloy. An example plunger whose tip portion was coated with Al ₂ O ₃ and a comparative example plunger whose entire tip was coated with a self-fusing alloy were created, and each plunger was attached to a different section of the IS machine to form a juice bottle with a capacity of 300 ml. Press blow molding was performed continuously. As a result,
The strength of the molded glass bottle was as shown in the table below.

[Table] In addition, a plunger as a comparative example was made and the entire body was coated with TiN, and it was installed in a different section of the IS machine together with the plunger of the above-mentioned example. The bottle was press-blow molded. When we investigated the incidence of broken mouth defects caused by internal injuries in molded glass bottles, we found that
The result is as shown in the table below.

[Table] (Effects of the Invention) As explained above, in the plunger for glass forming of the present invention, the mouth forming part is coated with a self-fusing alloy of H _V 800 or less, and the tip part is coated with ceramic. By doing so, it is possible to manufacture a glass bottle with high impact strength by preventing a decrease in strength due to peeling objects, and it has also succeeded in preventing scratches on the inner surface of the mouth of the glass bottle. As a plunger for glass molding that solves the problems of conventional products,
The contribution to the industry is extremely large.

[Brief explanation of drawings]

FIG. 1 is a front view illustrating the plunger for glass molding of the present invention, FIGS. 2 and 3 are front views illustrating a conventional plunger for glass molding, and FIG. 4 is a front view illustrating the plunger for glass molding of the present invention. It is a sectional view explaining a state. 1: plunger body, 2: self-fusing alloy, 3:
Ceramic material.

Claims (1)

[Claims] 1. A plunger for glass forming, characterized in that the mouth forming part of the plunger body 1 for forming a parison is coated with a self-fusing alloy 2 having an H _V 800 or less, and the tip thereof is coated with a ceramic material 3.