JPH0388734A - Device for forming precision optical glass - Google Patents

Abstract

PURPOSE:To obtain the device capable of forming an optical glass product in which a bruise is not caused in forming by providing an upper die retaining means for energizing and retaining the surface of the upper die above the lower die so that the surface is separated from the surface of the optical glass to be formed before the press stage. CONSTITUTION:The upper die 5 is raised by a spring 6, the optical glass material 7 to be formed is placed on the upper surface 3a of the lower die 3, and the upper surface 7a of the material 7 is separated from the surface 5b of the upper die 5. The material 7 is then heated to a specified temp. and softened, the upper die 5 is pressed by an upper platen 1 and lowered against the spring 6, and the material 7 is press-formed. A bruise is not caused in press forming, since the surface 5a of the upper die 5 is separated from the upper surface 7a of the material 7 until the heated material 7 is pressed.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a precision optical gate molding apparatus for molding precision optical glass such as an optical glass lens. [Prior Art] In recent years, optical glass lenses have been manufactured using not only conventional processing methods such as grinding and polishing, but also methods in which molten optical glass is directly press-molded using a mold, and optical glass lenses in which the optical glass material is shaped in advance to approximate the final shape. A method of press-molding reformed optical glass materials using a mold has come into use. Among the above-mentioned methods, from the viewpoint of labor-saving production and automation, the method of manufacturing by press molding is considered to be a promising method for producing optical lenses in the future. In particular, the method of press-molding a preform optical glass material is the most promising since it is excellent in terms of temperature control, etc., and equipment for carrying out this method has been developed and put into practical use. As mentioned above, the apparatus for press-molding optical glass lenses using preformed optical glass materials includes upper and lower platens, and a lower mold and an upper mold interposed between these platens. The optical glass material to be molded is placed on the lower mold, the optical glass material is heated to a predetermined temperature, and pressure is applied by the upper mold to form the press bottom of the optical glass material. It is structured to perform a form. [Problem to be Solved by the Invention 1] By the way, in the press processing apparatus according to the prior art described above, when the optical glass material to be formed is placed on the lower mold, the upper mold surface is For example, if the mold surface of the upper mold is convex, the load of the upper mold may cause dents on the surface of the optical glass molded product, or the upper mold may be damaged after molding is completed. There are disadvantages in that the mold releasability is poor and the life of the mold is significantly shortened. The present invention has been made in view of the above-mentioned points, and its purpose is to provide precision optical glass molding that makes it possible to form optical glass molded products that do not cause dents or the like during molding. The goal is to provide equipment. [Means for Solving the Problems 1] In order to achieve the above-mentioned object, the present invention provides that the upper mold of the upper mold and the lower mold inserted between the E lower platen has a is characterized by the provision of upper mold holding means for biasing and holding the mold surface in a state separated from the surface of the optical glass material to be molded. [Function 1] By adopting such a configuration, when the optical glass material to be molded is placed on the lower mold, the upper mold is separated from the optical glass material to be molded by the upper mold holding means. After heating the optical glass material to a predetermined temperature in this state, the optical glass material is pressurized and molded using an upper mold, so that there are no dents or the like on the molded product. Press bottom shape can be done. In addition, after the molding is completed, the upper mold can be separated from the molded product by the upper mold holding means.
The mold releasability is also improved, and the life of the mold can be extended. E Example 1 Hereinafter, examples of the present invention will be described in detail based on the drawings. The drawing is a cross-sectional view of a main part of an embodiment of a precision optical glass forming apparatus. In the drawing, 1 indicates an upper platen, 2 indicates a lower platen, and on the lower platen 2 there is a lower mold 3 and a lower mold 3 below the lower platen. A cylindrical mold 4 is installed that surrounds the mold 3 and extends upward from the upper surface 3a of the lower mold 3, and an upper mold 5 is provided within the mold 4 so as to be movable up and down. The upper mold 5 is configured to be lowered by the pressing force of the upper platen 1, and such a configuration is well known in this type of molding apparatus. However, the feature of this embodiment is that a spring 6 as an upper mold holding means is elastically mounted between the upper surface 4a of the adjusting mold 4 and the flange portion 5a of the upper mold 5. The spring 6 is made of a material with good heat resistance such as ceramics, and when the preform optical glass material 7 is placed on the upper surface 3a of the lower mold 3, the spring 6 is made of a material with good heat resistance such as ceramics. The surface 5b is spaced apart from the upper surface 7a of the glass material 7 by a predetermined distance. In addition, here, the upper mold 5
Since the upper mold 5 moves up and down, it goes without saying that the spring B is formed so as not to become an obstacle when the upper mold 5 moves to the stroke end of the lowering operation. The present embodiment is constructed as described above, and the preform optical glass material 7 is moved to the lower mold 3 while the upper mold 5 is pushed upward by the action of the spring 6 as shown in the drawing. It is placed on the upper surface 3a of the. As a result, the upper surface 7a of this optical glass material 7 is separated from the mold surface 5b of the upper mold 5. Therefore, the optical glass material 7 is heated to a predetermined temperature to soften it, and in this state, a pressing force is applied to the upper mold 5 by the upper platen 1, and the upper mold 5 is lowered against the spring 8. , the optical glass material 7 is press-molded. In this way, until the optical glass material 7 is heated and pressing is actually started, the mold surface 5a of the upper mold 5 is kept in a non-contact state with the upper surface 7a of the optical glass material 7. By doing so, there is no risk of creating dents during press molding.Also, when heating the optical glass material 7, the spring 6 is also heated at the same time, but the spring 8 is made of a material with good heat resistance. Because it is,
There is no problem of deformation or deterioration of it. After the molding is completed as described above, the pressing force applied to the upper die 5 by the upper platen 1 is released. As a result, the mold surface 5b of the upper mold 5 is displaced in the direction away from the molded product due to the action of the spring θ.
The release of the upper mold 5 from the molded product is facilitated. In this way, when the upper mold 5 has good mold releasability, the upper mold 5 can be protected and its lifespan can be extended. Incidentally, in the above-mentioned embodiment, the lower mold 3 was formed separately from the adjusting mold 4, but the lower mold and the adjusting mold may be formed integrally. In addition, although a configuration is shown in which a spring is loaded between the upper mold 5 and the adjusting mold 4, this spring can be loaded between the upper mold and the lower platen 2, or between the lower mold and the adjusting mold. If the mold is integrally formed with the mold, the mold may be loaded between the mold and the lower mold.

【Effect of the invention】

As explained above, according to the present invention, the upper mold is held apart from the upper surface of the preform optical glass material at least at a stage before the start of the pressing process, so that the optical glass material can be used during press molding. There are various effects such as no dents being caused on the mold, good mold releasability after press molding is completed, and the life of the mold can be extended.

[Brief explanation of drawings]

The drawing is an explanatory diagram of the main part configuration showing one embodiment of the present invention. 1: Upper platen, 2: Lower platen, 3: Lower mold, 4: Adjusting mold, 5: Upper mold, 6: Spring, 7: Preform optical glass material.

Claims (1)

[Claims] In an apparatus for press-molding a to-be-molded optical glass material placed on the lower mold by inserting an upper mold and a lower mold between upper and lower platens, at least before the pressing process, the mold surface of the upper mold is A precision optical glass molding apparatus comprising an upper mold holding means for biasing and holding an optical glass material to be molded in a state separated from the surface thereof.