JPS58185438A - Preparation of plate molded article - Google Patents

Abstract

PURPOSE:To prepare a plate molded article at a low cost in high yield, without using a grinding step, by cooling a melt in a crucible having a polygonal orifice provided at the bottom to such a temperature as to give a suitable viscosity coefficient, and drawing down the melt through the orifice. CONSTITUTION:A crucible 4 having a tetragonal orifice 3 at the bottom thereof is placed in an electric furnace 1 having a heating element 2, and quartz glass as a melt is contained in the crucible 4. The melt is then heated to a temperature higher than the operating temperature to refine the melt. When bubbles, cords, etc. disappear in the glass, the melt emerging from the orifice 3 is cooled to 10<4>-10<7> poises viscosity coefficient within the operating temperature range. The melt emerging from the orifice 3 is then drawn down to prepare a plate molded article 5, which is then annealed and cut to prepare a plate.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a flat plate molded body for producing a flat plate molded body at low cost and with high yield without going through a polishing process from a high-temperature melt such as glass or devidroceramics. Regarding the manufacturing method of molded bodies @ [Technical background of the invention and its problems] Conventionally, in order to make laths, etc. of flat plates for optical glass and electronic devices, a gob is removed from the molten body melted in a crucible. Flat glass is manufactured through a polishing process after press forming. However, this method has had the problem of high material costs due to polishing. For example, in order to make flat glass by polishing, it is first roughly polished to the desired thickness and then processed into a transparent or mirror-like flat plate using a fine abrasive such as cerium oxide or alumina. Ta. In this method, the polishing cost is extremely high and exceeds the glass patch cost. Therefore, it has been desired to realize a method for efficiently manufacturing flat glass without going through a polishing process. In addition, the glass material was rapidly consumed during polishing, the polishing process was complicated and took a long time, and the cost of the polished product was several times higher than that of the pressed product. Although the process for press products is simple, they have drawbacks such as difficulty in achieving flatness.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a flat plate molded body, which can produce flat plate molded bodies with good yield without using koji during the polishing process, and which can reduce manufacturing costs. [Summary of the Invention] When producing a flat plate molded body, the present invention accommodates a melt in a crucible with a polygonal orifice at the bottom, refines the melt at a temperature higher than the working temperature, and then melts the melt. The viscosity coefficient of the body is 10' to 10' (pols@)
In this method, the melt is cooled to a temperature such that In addition,
Its viscosity coefficient is 10' as a pre-processing force to pull down the melt.
The reason why the melt was cooled to 10" [pole.] is that when the viscosity coefficient exceeds to' (p.1.), the glass becomes too hard and the melt does not come out from the orifice. If the temperature is below [p@%l・], the molten material comes out too quickly and cannot be formed into an appropriate thickness.Then, the molten material that comes out of the orifice is slowly cooled to eliminate cracks and to reduce distortion. A flat plate molded body is obtained by removing and cutting with a cutter.

〔Effect of the invention〕

According to the present invention, by carrying out the above-mentioned fining process, a glass without defects or non-uniform parts due to non-uniformity such as bubbles, striae, and stripes in the glass can be obtained, and the working temperature 1 (to The molten material, which has a diameter of 10' palm. Furthermore, by combining the fining process, the drawing process 11, and the process of specifying the viscosity coefficient, the yield is 90 (5
It is possible to obtain a yield of 1 or more at a cost which is a fraction of the cost of a flat plate molded body obtained by a normal grinding machine. Moreover, the flatness of the obtained glass is 4×4
With an area of 9, 1O (7zm 1st) is obtained.

[Embodiments of the invention]

The first WA is a model showing the schematic configuration of a flat plate molded body manufacturing apparatus used in an embodiment method of the present invention. In the figure, 1 is an electric furnace having a heating element 2 (molybdenum silinide or silicon carbonate), and a platinum or sillimanite crucible 4 having a rectangular orifice 1 at the bottom is disposed inside this electric furnace 1. has been done. A molten material is housed within this crucible 4.

Quartz glass was housed as a molten body in the crucible 4 using such Ij & Haji, the molten body was heated to a temperature higher than the working temperature, and the molten body was clarified and processed. Then, when there are no bubbles or striae in the glass, the viscosity maintenance line t O' = 10' in the working temperature range exits from the orifice 3.
The melt was cooled to 81 m·). Thereafter, the melt was pulled down from the orifice 1 to produce a flat plate molded body 5. This flat plate molded body 5 was slowly cooled and then cut. The flatness of the thus obtained workpiece was 10 (μm). Furthermore, since there were no cracks on the glass end face, the yield was 95% even considering the consumption of the material.

The second @ is a configuration diagram showing a schematic configuration of a flat plate molded body manufacturing apparatus used in another example method. Similar to the apparatus shown in FIG. 1, a crucible 4 is disposed within an electric furnace 1, and a recess 6 is provided at the bottom of the crucible 4. The method of this example is suitable for porcelain products due to its viscosity. First, alkali and 20% gold-containing borosilicate glass are used, and the melt is placed in a 111 g recess of crucible 4, and nitric acid is used as a fining agent. Add 0.5 arsenous acid or antimony oxide to soda
[%] is added to the batch, and when the melt is sufficiently homogeneous and the bubbles are well removed, insert the platinum rod 1 to the bottom of the recess C to push out the melt, and place it in the crucible 4.
Take out the molten material from the orifice 3 at the bottom of the lid body 5.
Take out. After slow cooling, it was cut to obtain a flat plate.

The flatness of the plate thus obtained is j(-], and the yield is 9.
It was 0 [%].

As mentioned above, this method can omit the polishing process, and does not include polishing machines, polishing materials, cleaning of polishing, etc., so the flat plate molding can be produced at a fraction of the conventional cost, and the yield is high, making it suitable for industrial use. It can be said that this is an excellent flat plate layering method.

It should be noted that the present invention is not limited to the embodiments described above, but can be implemented with various modifications without departing from the gist thereof. For example, the orifice may have a shape other than a quadrangle, a triangle, a pentagon, or a larger polygon. In addition to glass, molten materials include ceramics, crystals,
Other molten salts may also be used. In addition to glass for the electronic industry, it can of course be applied to the production of a wide range of flat plate laminated bodies, such as optical glass, colored filter glass, ultraviolet and infrared filter cover glass, and photomask glass.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the general configuration of a flat plate molded body manufacturing device used in one embodiment of the method of the present invention, and FIG. 2 is a schematic diagram showing the schematic configuration of a flat plate laminate manufacturing device used in another embodiment. It is a diagram. l... electric furnace, 2... heating element, 1... crucible, 4
... Orifice, 5... Molded body, 6... Recessed part, r... Platinum rod.

Claims (1)

[Claims] A process of placing the melt in a crucible with a polygonal orifice at the bottom, heating the melt for 4f at a temperature higher than the working temperature, and then heating the melt to a point where the viscosity coefficient of the linear melt is 1.
A flat plate characterized by comprising a step of cooling to a temperature of 0' to 1 G' (polse), and then a step of pulling the melt down from the orifice of the crucible and slowly cooling the pulled down melt. Method for manufacturing a molded body.