JPH09278457A - Forming method of glass by using die not coated with oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent defects in a product which are caused in the initial period after dies are changed and to improve the production yield in the forming process of glass by using a die not coated with oil (oil-free die) consisting of a specified alloy having an alumina coating film on the surface, by using a die having such a structure that a solid lubricant layer is deposited on a specified part. SOLUTION: When a glass is formed by using an oil-free die made of a Fe-Cu-Al alloy having an alumina coating film on the surface, the die used has such a structure that a solid lubricant material (e.g. boron nitride) layer is deposited on the surface 2 of a part where a molten glass 1 to be inserted in the die deforms most prior to changing dies. Namely, defects produced just after the operation is started after dies are changed are produced in the part where the molten glass inserted in the die deforms most. This is because the frictional coefft. between the alumina film and the glass is large to give bad lubrication. This phenomenon disappears by increasing the temp. of the die. Therefore, by increasing the initial lubricating property in this part, the problem can be solved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to Fe--Cu--Al.
The present invention relates to a manufacturing method for eliminating defects and improving yield when molding glass using an oil-free mold made of a base alloy.

[0002]

2. Description of the Related Art Glass molding is performed by cutting off molten glass of 1000 ° C. or higher, introducing it into a tub and inserting it into a mold at a high speed, and then removing the heat by bringing the molten glass into close contact with the mold surface in a blowing or pressing process. Molding is completed. Glass molding dies are generally made of cast iron, heat resistant steel, etc., but glass molding dies made of these materials are
When molten glass at a high temperature is inserted and comes into contact with the surface of the mold, the reaction between the glass and the surface of the mold causes poor mold release of the product and also deteriorates the surface properties of the glass.

For this reason, it is customary to operate the mold for glass molding while applying an oil-based mold release material mainly containing graphite at intervals of 15 to 30 minutes. However, this mold release material is burned after oiling to deteriorate the working environment, graphite is burned on the mold to roughen the surface of the product, and graphite is attached to the glass surface to cause deterioration in quality. . For this reason, there has been a strong demand for a so-called uncoated oil operation in which a mold release material is not used in the glass forming process.

Therefore, the inventors of the present invention have disclosed in Japanese Patent Laid-Open No. 6-1007.
No. 9, JP-A-6-279944 or Japanese Patent Application No. 7-030768, a glass-molding mold of Fe—Cu—Al alloy having a self-forming coating of alumina on its surface was proposed. This mold is heat treated in an oxidizing atmosphere,
Al contained in the alloy diffuses on the surface to form a dense alumina film, and this film prevents seizure between the molten glass and the mold and exhibits good mold release properties. Further, this mold has high strength at high temperature and excellent corrosion resistance, and the thermal conductivity can be varied by adjusting the alloy composition. When actually making glass bottles using these molds,
Even if the release agent was not applied with oil, the glass could be easily released from the mold, and it was possible to operate without oil for a long time.

However, in the glass forming operation using these oilless molds, defects may occur in the product immediately after the mold is changed depending on the size and shape of the product, and the yield may be reduced. Sometimes.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to improve the product yield by eliminating the product defects that occur at the initial stage of mold replacement when glass molding is performed using an oilless mold. Is to provide a method.

[0007]

Means for Solving the Problems The present invention is as follows. Fe-Cu- with an alumina coating on the surface
When performing glass forming using an oil-free mold made of Al alloy, a solid lubricating substance layer is attached to the surface of the place where the molten glass inserted into the mold is most deformed before changing the mold. A method for molding glass using the mold thus obtained.

Hereinafter, the present invention will be described in detail. Current,
Mass production of bottles is done in an automatic bottle machine line,
When a defect such as a defect occurs in the product due to the mold, the mold is replaced, that is, the mold is changed. The preliminary mold for changing molds is 200 to 250 ° C in an electric furnace in advance.
After the mold has been preheated to some extent and the mold has been changed, when the molten glass starts to be inserted, the mold temperature rises, and when the temperature reaches 350 ° C. or higher, the product can be manufactured. In glass molding using a mold having an alumina coating proposed by the present inventors,
We investigated in detail the defects that occurred at the beginning of the operation immediately after the mold change, and found that when the molten glass was inserted into the mold by its own weight drop following the trough, for example, in the case of a bottle molding mold, the mouth mold at the bottom of the barrel mold was used. It was found that a defect occurs at the part that is most deformed when narrowed down.

This is because the friction coefficient between the alumina coating and the glass is large, so that it is difficult to slip, and further, when the mold temperature is low because the molten glass comes into direct contact with the mold, the molten glass has a viscous surface. Since a high shell is formed and it becomes difficult to deform, the molten glass is hard to enter the mold, which causes defects such as wrinkles. When the insertion of the molten glass is further continued, the mold temperature rises, the highly viscous shell formed on the surface of the molten glass becomes thin, and the defects disappear. Therefore, as a measure until the mold temperature rises to the proper temperature range,
It was found that the lubricity of the portion of the molten glass that is first deformed in the mold should be increased.

First, the parts in the molding die for improving lubricity will be described. Since the glass molding die is designed so that the thickness is uniform depending on the shape of the product and the glass composition, the portion where the molten glass is first deformed in the die is different. 1 (a) and 2 (a) show a cross-sectional shape of the mold and a state when the molten glass is inserted and brought into contact with the mold, and FIGS. 1 (b) and 2 (b) show the molten glass. The state at the position stopped after insertion is shown. Both of them are located under the mold, but in the mold of FIG. 1, the range of the part that deforms the glass is determined by the diameter of the molten glass, and in the mold of FIG. 2, it is the part along the prepared hole of the mold. Therefore, the solid lubricating layer may be formed at the portion 2 shown in FIGS. 1 and 2.

Next, a method for improving lubricity will be described. A solid lubricant excellent in high-temperature stability was used under the condition that the mold temperature was up to 350 ° C. and the molten glass having a surface temperature of 700 to 800 ° C. was in contact. Moreover, a carbon-based or boron-nitride-based solid lubricant that is capable of forming an extremely thin layer so that the necessary amount is present only at the initial stage of mold changing is suitable. However, the boron-nitride type, which has less adhesion to glass than the carbon type, is preferable. When boron nitride was used as the solid lubricant, a boron nitride molded product having a particle size of 0.3 to 0.7 μm was easy to fit in the mold and a thin layer could be formed.

The point of the method of forming the solid lubricating layer is how to make it thin and convenient only in the required portion of the mold. The inventors need to lubricate the inner surface of the mold as shown in FIG. 3 for the mold having the shape shown in FIG. 1 and as shown in FIG. 4 for the mold having the shape shown in FIG. A boron nitride molded product was processed so as to match the shape of the part, and a solid lubricating layer forming jig with a supporting rod was manufactured. The jig has a structure in which the upper hole (molten glass insertion hole) guide 4 and the lower hole (joint hole with the die) guide 5 are positioned so that the shape of the jig follows the required portion of the die. By rotating the solid lubricant block 3, the solid lubricant can be attached to the mold.

Further, the spring 6 and the stopper 4 for adjusting the pushing distance are provided so that the solid lubricating layer is formed with an appropriate pressing pressure even when the inner surface shape and size of the mold are different. When a solid lubricating layer was formed on the mold before preheating using this jig, the thickness of the layer required for the rise time for mold replacement was sufficient if the support rod was rotated 2-3 times. Even if it was rotated further, the adhesion amount did not become large, and it did not become excessive. When the mold subjected to the above treatment was mounted on a bottle manufacturing line and the bottle was manufactured, the product yield in the initial stage of operation was improved.

The present invention will be described below with reference to examples. Example 1 In an automatic bottle line for producing a glass bottle having a weight of 150 g, an upper hole diameter of 3 having a shape as shown in FIG.
When forming a glass bottle with a diameter of molten glass of 30 mm using a mold of 5 mm, lower hole diameter 28 mm, and height 120 mm, press the mold with a solid lubricating layer forming jig using boron nitride. Two rotations were performed at a pressure of 2.8 kg, and a solid lubricating layer was formed 17 mm from the bottom along the circumference. After heating this mold in a preheating furnace set at 280 ° C. for 1 hour, the mold was changed and a bottle was manufactured. As a result, it was possible to manufacture a product having no defects from the initial stage of operation.

Example 2 In an automatic bottle line for producing a glass bottle having a weight of 80 g, an upper hole diameter of 29 mm having a shape as shown in FIG.
When using a die with a lower hole diameter of 22 mm and a height of 80 mm to form a glass bottle with a molten glass diameter of 29 mm, press the die with a solid lubricating layer forming jig using boron nitride 1 2 rotations at 2 kg, 3 mm around the bottom hole
A solid lubricating layer was formed on the part. After heating this mold in a preheating furnace set at 250 ° C. for 1 hour, the mold was changed and a bottle was manufactured. As a result, a product without defects could be manufactured from the initial stage of the operation.

[0016]

According to the present invention, it is possible to manufacture a glass product having no defects from the beginning of the operation immediately after the mold change, and the product yield is improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a cross-sectional shape of a glass molding die and a portion on which a solid lubricant layer is formed, (a) is a state in which molten glass is inserted and is in contact with the die, and (b) is a molten state. The glass is deformed by its own weight.

FIG. 2 is an explanatory view showing another cross-sectional shape of a glass molding die and a portion where a solid lubricant layer is formed,
(A) is a state in which molten glass is inserted and is in contact with the mold,
(B) The molten glass is deformed by its own weight.

FIG. 3 is a schematic view showing a jig for forming a solid lubricating layer of the present invention.

FIG. 4 is a schematic view showing another solid lubricating layer forming jig of the present invention.

[Explanation of symbols]

 1 Molten Glass 2 Part for Forming Solid Lubrication Layer 3 Solid Lubricant Block 4 Positioning Part and Stopper for Upper Hole 5 Positioning Part for Lower Hole 6 Spring 7 Handle

Claims (1)

[Claims] 1. Fe-Cu- having an alumina coating on its surface
When performing glass forming using an oil-free mold made of Al alloy, a solid lubricating substance layer is attached to the surface of the place where the molten glass inserted into the mold is most deformed before changing the mold. A glass molding method using an oil-free mold, which is characterized by using a mold made by the above.