JPH01203234A - Device for forming optical element - Google Patents

Abstract

PURPOSE:To prevent the galling and biting of a cut member and to obtain an optical element with precision in dimensions and weight by cutting off the surplus part of a molten glass material with a forming device of specified structure. CONSTITUTION:A cutting member 7 movable along the periphery of a forming die member 6 and used for cutting off the surplus part of a molten glass material is provided on the periphery of the member 6 for press-forming the material, a minute gap of 20-50mu is held between the inner periphery of the blade head of the cutting member 7 and the periphery of the member 6, and a temp. control means for holding the gap at a specified value is provided in the cutting member 7. In such a forming device, molten glass 2 is discharged from a nozzle 1, the opposed die member 5 and 6 held at a specified temp. are driven to press the part of the molten glass 2 except the tip with forming faces 5a and 6b to a specified thickness, the cutting member 7 is slid back and forth along the periphery of the die member 6 in the direction of the die member 5 to cut off the surplus glass material 22, and the formed part 21 is cooled from the periphery and taken out.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an apparatus for molding optical elements by press molding, and more specifically, the present invention relates to an apparatus for molding optical elements by press molding, and more specifically, the present invention relates to a molding device for optical elements by press molding, and more specifically, it is possible to improve surface accuracy without going through processes such as grinding and polishing after press molding. The present invention also relates to an optical element with good weight accuracy or a preform molding apparatus suitable for reheat pressing thereof.

(Prior Art) A glass material is housed in a mold and press-molded to achieve a predetermined surface accuracy.

High-precision light that eliminates the need for post-processing such as grinding and ω1 polishing'?
A method for molding raw material has been developed.

This press molding method generally includes a reheat press method and a direct press method.

In the reheat press method, the necessary 1 d of glass material that has been melted and solidified in advance is cut, the weight is adjusted by a method such as sanding, and the resulting glass pellets are placed in a mold for molding. After heating the molds simultaneously or separately to the pressing temperature, press molding is performed and the optical character functional surface formed on the molding mold is suppressed and transferred to form the optical character. This is a method of molding elements.

- On the other hand, in the direct press method, the necessary amount of the molten glass flowing out or extruded from the molten glass outlet is cut by a cutting blade, and the cut is directly dropped into a molding container or thrown into a chute. After that, press the mold and light it. This is a method for molding elements.

In addition, in the above-mentioned reheat press method, molten glass can be used for molding as in the above-mentioned direct press method, without going through the process of cutting and sanding, which has low productivity! 1 and press-form the preform into a shape similar to that of the final product. Highly accurate light′? For molding with 41 machine functions! There is a method of press-forming by placing it in a container.

(Problems to be Solved by the Invention) Optical elements obtained by these molding methods are required to have a certain surface accuracy and r-method accuracy in order to obtain good image forming quality, and for this reason, the In either method, the glass material fed to the press molding to obtain the final product must be partially weighted.

However, in the above-mentioned method of press-molding using small glass lumps, since the heavy electrical adjustment of the glass small lumps is performed by cutting and sanding, grains may remain on the surface of the molded product.
When heating small glass lumps before press forming, the adhesive applied to prevent the glass and heating tray from fusing together bites into the surface of the molded product during pressing, significantly deteriorating the surface accuracy of the molded product. There is a problem with doing so.

In addition, in the method of press forming directly using molten glass,
When cutting with a cutting blade, cutting marks called shear marks are generated on the molded product, which causes a problem in that the surface precision of the molded product deteriorates. In addition, in this press molding method, the center of the molded product is adjusted by cutting the molten glass flow, so the molded product may be subject to weight rl fluctuations due to temperature changes in the molten glass flow, cutting timing, or pulsation of the glass flow. There is also the problem that predetermined dimensional accuracy cannot be obtained.

In addition, it especially prevents the occurrence of shear marks! Examples of the press molding method include those described in Japanese Patent Publication No. 41-9190 and Japanese Patent Application Laid-Open No. 61-13252:3.

In the molding method described in Japanese Patent Publication No. 41-9190, press molding is performed by pressing a mold in a direction perpendicular to the direction of flow of molten glass to fill the mold cavity with molten glass. Pressing the mold for molding 1. At the time of F, a phenomenon occurs in which excess glass in the mold cavity flows out from between the mold and the anvil facing the mold. As the pushing motion of the mold progresses, this excess glass increases its outflow resistance and is cooled by the mold, increasing its viscosity, and this increases the viscosity between the mold and the opposing anvil. It is cooled without being completely cut out, and a protruding portion is formed on the outer periphery of the molded product. For this reason, after press molding, it is necessary to break the IllL portion and to clean up the broken surface. Furthermore, due to variations in the size of the molten glass flow, the glass thickness between the above-mentioned molded product and the protruding portion changes, causing variations in the thickness of the molded product, making it difficult to adjust the weight with high precision. There is also the problem of not having one.

On the other hand, in the molding method described in JP-A No. 61-13251, the precision of the molded product depends on the size of the flowing glass body before punching it. A rod or glass sheet with dimensions and shape is required.

In order to solve the problems mentioned above, the present inventors arranged a pair of molds facing each other so as to sandwich the glass fluid therebetween, and set the cavities of the molds to +i? After pressing the glass fluid J to the mold to form a molded part, + cutting and separating the molded part mI from other parts using a cutting member provided on the outer periphery of the mold. A method for manufacturing an optical element r characterized by the following has already been proposed.

According to this method, the functional surface of the molded product can be formed while avoiding cutting traces of the glass fluid, and the outer peripheral side of the molded product can be formed with high precision using the cutting member provided on the outer periphery of the mold. An optical element with excellent dimensional accuracy and 1iit accuracy without surface defects such as marks can be obtained.

The present invention relates to an apparatus suitable for this type of manufacturing method, and is configured to prevent galling caused by thermal expansion of the mold when the cutting member slides on the mold. The purpose is to provide a molded product (a).

If this kind of galling occurs, the cutting member will not adhere to the molding glue 1.
Not only is it impossible to move smoothly around the outer periphery of the cutting member, but even worse, the cutting member gets stuck in the mold and cannot be moved at all, which can lead to a situation. Moreover, if the cutting member is worn out by the mold and the cutting edge of the cutting member gets stuck, the outer periphery of the cut molded product will be roughened and chips will adhere, which is undesirable.

(Means for Solving the Problems) In order to solve the problems of the related art, the optical element molding apparatus of the present invention has a method of forming a predetermined interval on the outer periphery of a mold for press-molding a molten glass material. A cutting member is provided to cut the surplus portion of the glass material while maintaining the cutting member, and a predetermined gap is formed between the mold and the cutting member on the inner periphery of the blade head of the cutting member, and an O; 1. A heating means capable of temperature control is provided so as to maintain the gap at a predetermined value of 1 t.

(Function) In the optical element molding apparatus configured as described above, the outer periphery of the mold is kept at a predetermined distance from the mold. An IJ cutting member is provided. The cutting member moves along the outer periphery of the mold and cuts the excess portion of the molded product formed by the mold to form the outer peripheral shape of the molded product.

Furthermore, a slight gap is provided between the inner periphery of the J head, which constitutes the vicinity of the tip of such a lino cutting member, and the mold. Here, l', ;L! The knife head does not constitute only the tip of the cutting member (MeJ tip), but has a certain width from the 1.3 tip. It is important that the blade head be constructed to such an extent that it will not come off from the mold during the cutting movement. With this configuration, when molding the glass material, the glass material does not enter the gap between the mold and the cutting member, and when the cutting member moves around the outer periphery of the mold, the cutting member There is no possibility of galling or sticking to the mold.

Further, in the present invention, a temperature-controllable heating means is provided within the cutting member so as to maintain the slight gap between the blade head and the mold at the initial distance. - The small voids mentioned above easily fluctuate due to thermal expansion of the mold when the mold is heated, and when the cutting member moves around the outer periphery of the mold, the cutting member Although there is a possibility that galling or sticking may occur with respect to the cutting die, such galling or sticking can be prevented by heating the cutting member and thermally expanding it using the heating means described in 1-1. This is oral ability. Further, the thermal expansion of the cutting member can be adjusted by a one-time control provided on the heating means. A thermocouple for temperature detection can be applied as a means for configuring the temperature control, but such a temperature detection means is particularly necessary to control the temperature of the blade head, so it is necessary to provide it near the tip of the cutting member. This is desirable.

With the above configuration, it is possible to maintain a small gap between the mold and the blade head of the cutting member at the initial distance without being affected by the thermal expansion of the mold, thereby preventing galling or gouging of the cutting member. It is possible to prevent sticking.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of an apparatus according to an embodiment of the present invention. Second
7 are diagrams showing an example of application of the apparatus shown in FIG. 1, and show operating conditions in the order of steps 21-7.

First, as shown in FIG. 1, the main parts of the apparatus of this embodiment include a mold member 6, a cutting member 7, a cutting ring 7 as a heating member, a heater 25 as a heating means, and a thermocouple 2 as a temperature detecting means.
It consists of 6.

Cutting ring 7 is J□! They are provided at predetermined intervals on the outer periphery of the mold member 6, and are movable along the outer periphery of the mold member 6 by a driving means (not shown). The mold member 6 has a molding surface 6a.
is provided and faces the molding surface 5a of the opposing mold member 5, and during press molding, a glass material is supplied between these molding surfaces to suppress and transfer the molding surface of the person. [-
The distance between the cutting ring 7 and the die member 6 shown is relatively large (
It's fine.

Furthermore, the outer periphery of the mold member 6 and the cutting edge 0 part 7a of the cutting ring 7
The inner periphery is configured to have a small gap 24. The width of the blade head 7a is configured to such an extent that the blade head does not come off from the mold member 6 when the cutting ring 7 moves around the outer periphery of the mold member 6. The spacing between the voids 24 is preferably 20μ to 5()μ. If the gap 24 is configured to be smaller than 20 μm, it is difficult to control the temperature of the cutting ring 7 to adjust the thermal expansion as described below, and the mold member 6 is likely to be galled. If the gap 24 is configured to be larger than 50 μm, the glass material will easily enter the gap during press molding, and the movement of the cutting ring 7 will be hindered. Also, in this case, the molded product will have some stiffness, which is not desirable.

Suitable materials for the mold member 6 and cutting ring 7 include super alloys such as WC1, heat-resistant metals such as SUS, carbon steel tool steels such as SKD, and heat-resistant materials other than metals such as ceramics and cermets such as 5iC1A1□03. are selected depending on the usage atmosphere, required temperature, and glass material used. Note that it is desirable to select a material for the cutting ring that has better wear resistance than the mold member.

As an example of 14 bodies, 5F as a glass material in an atmospheric atmosphere.
8 (gob temperature = 800°C) was molded. SU as mold material
S. Use SK as the material for the cutting ring 7, fill the gap 24 between the mold and the cutting ring to about 25 to 30μ, and mold the mold member 6.
When press molding was carried out with the temperature set at 400°C and the cutting ring 7 at 300°C, good molding results were obtained with no galling between the cutting ring 7 and the mold member 6, and no flashing in the molded product. Ta.

A thermocouple 26 for temperature detection and a heater 25 for heating are provided inside the cutting ring 7. These thermocouples 26
The heater 25 is installed near the tip of the cutting ring 7 so as to detect and heat the temperature around the cutting edge 7a. A controller 28 is provided outside the molding apparatus, and the controller includes a power regulator 28a and a temperature regulator 28b. The heater 25 is connected to a power regulator 28a, the thermocouple 26 is connected to a temperature regulator 2528b, and the measured value detected by the thermocouple 26 is sent as an output control signal to the power regulator 28a, and the power regulator 28a controls the temperature. The cutting ring 7 is heated by the heater 25.

The cutting ring 7 is also heated and thermally expanded in accordance with the thermal expansion of the mold by the heater 25 equipped with temperature control means, and the initial spacing of the gaps 24 is maintained.

Reference numeral 31 denotes a heater that heats the mold member 6. This heater has a built-in thermocouple for detecting the mold temperature, and is connected to a controller such as the one provided in the cutting ring 7 described above, making it possible to control the temperature. .

The present embodiment device η described in the press molding device shown in FIG.
A mold member 6, a cutter 7, etc. are provided. Below,
This press molding device will be explained. However, in FIG. 2, the heater 25 and thermocouple 26 built into the cutting ring 7 are not shown.

1 is a nozzle through which molten glass flows out from a melting furnace (not shown), and a glass fluid 2 flows out from this nozzle. 4
is a cutting blade that is provided below the nozzle 1 and cuts the glass fluid 2 by opening and closing operations by a drive device (not shown).

The press molding apparatus n shown in this embodiment is constructed to be of a type in which the glass fluid 2 flows from a nozzle l, and has a first mold member 5 and a second mold member constituting l pair of molding molds. 7 so that the mold members 6 of 2 sandwich the glass fluid 2 from substantially perpendicular directions.
7. It is placed facing each other.

As described above, each mold member 5.6 has molded portions 5a, 6a whose opposing surfaces are mirror-finished. The first mold member 5 and the second mold member 6 are moved in directions substantially perpendicular to each other with respect to the outflow direction of the glass fluid 2 flowing from one side by a driving source such as a cylinder (not shown). A suppression action is performed. However, these first
The second mold member 5.6 can be opened and closed independently by a separately provided drive source, and the operating stroke of the mold member 5.6 can be adjusted to adjust the distance between the two mold members during pressure molding. By setting 5! The wall thickness of the molded product to be manufactured can be adjusted.

A guide block 14 is provided on the outer periphery of the mold member 6 and is fixed to the cutting ring 7 to surround the cutting ring 7, and this guide block 14 is fixed to the support member 10.

Further, a guide block 1:3 is provided on the outer periphery of the mold member 5 and surrounds the mold member 5, and this guide block +
3 is supported by a support member 11. Support member 10.1
1 are each connected to a driving source (not shown) such as a cylinder,
The support members 10 and 11 are actuated by the drive source, respectively, by a single movement of sVL/. By the operation of the support member 10, the cutting ring 7 fixed to the guide block 14 reciprocates while sliding on the outer periphery of the second mold member 6 in the direction of the first mold member 5. Also, by the operation of the support member 11, the first mold member 5
moves back and forth in the direction of the second mold member 6.

Further, a guide bin 15 is fixed to the guide block 13 so as to protrude toward the guide block 14 side.

The guide block 14 is provided with a guide hole 16 into which the guide bin 15 fits and slides.

When the guide plotters 13, 14 operate and approach the stagnation, the guide bin 15 slides within the guide hole 16 and guides the suppressing operation of the mold members 5, 6.

Inside the mold member 5.6 there is a heater: SOl; 31
is provided, and the mold member 5.6 is heated to a predetermined temperature by this heater.

Also, inside the 2 guide blocks 13 and 14 are people Hilter 32.
．． :S3 and thermocouples 34.35 are provided. A plurality of heaters 32, 33 are provided within the guide block 13, 14 at positions where the respective guide bins 15 and guides (Li2) can be heated evenly so that the mutual pitches thereof maintain a predetermined interval. .35 temperature test) 11
The temperature is controlled by an external controller.

Next, the operation of this apparatus will be explained using FIGS. 2 to 7 and FIG. 8.

2 to 7 are main part sectional views showing the operating state of this device in each process order, and FIG. , is a timing chart showing the actuation timing of the troughs of the cutting blade 4 and the cutting ring 7, where the horizontal axis represents time 1°.The actuation timing of these actuating parts is determined by a controller (not shown) connected to each actuating part. can be controlled.

FIG. 2 shows a state in which the press molding direction is O1j, and the glass fluid 2 is flowing from the nozzle 1. When the tip of the glass fluid 2, that is, the cut mark 3, flows downward from the opposing molding surfaces 5a, 6a, the first mold member 5 and the second mold member 6 start to be suppressed. In this suppressing operation, the guide bin 15 fits into the guide hole 16 and slides, and even if the mold members 5.6 are slightly misaligned, the mold members 5.6 are guided by the guide member and the shaft is moved. The deviation is corrected by IF.

In FIG. 8, T=0 indicates the timing at which both mold members 5.6 start operating. The operation start timings of these mold members 5 and 6 may be the same for both, but the timing of the suppression operation path r' of the mold members 5 and 6 against the glass fluid 2 is the same or at most ±0.05 s. It is preferable to keep the difference within the range. If this difference is large, only one end J of the 1141 member 5.6 collides with the glass fluid 2, causing the glass fluid 2 to shake horizontally. Thereafter, the mold member 5.6 presses the molded portion 21 of the glass fluid 2 at t-1, as shown in FIG.
- Maintain this state for a predetermined period of time, during which time the part to be formed 21
Pressing I by the respective molding surfaces 521.6a against both surfaces of
F transfer is performed.

The operation start time and cutting start time of the cutting blade 4 may be at the same time as the operation start time of the human-shaped member 5. 1
1 must be at the same time as, or at least after, the mold member 5.6 retains the glass fluid 2.

Thereafter, the cutting blade 4 is returned to its original state. 8th
In the figure, the return start time of the cutting blade 4 is indicated as 1.4, and the return end time is indicated as T. Preferably, the time required from the operation start time 1'=0 of the cutting blade 4 to the return start time '4 is 0.3 to 0.4 seconds.

As shown in FIG. 5, the operation start timing of the cutting ring 7 is at least when the cutting ring 7 finishes cutting the outer periphery of the part to be formed 21 (1' 3 )+ii+, and the cutting blade 4 finishes cutting the glass fluid 2. It is preferable to set the angle 7' (T). By doing this, the glass fluid 2 is already cut off by the cutting blade 4 when the cutting operation of the cutting ring 7 is finished, and the cut piece 22 cut by the cutting ring 7 is easily attached to the first mold member. 5 into the external or annular groove 40.

In this way, the cutting ring 7 cuts the outer periphery of the molded part 21 while sliding along the outer periphery of the second mold member 6, thereby forming the outer peripheral shape of the molded part 2I.

Thereafter, the cutting ring 7 maintains the state at the end of cutting (T3), cools the molded part 21 from the outer periphery due to the temperature difference while holding the outer periphery of the molded part 2I, and cools the molded part 21 from the outer periphery near the outer periphery of the molded part 21. increases in viscosity and fixes its shape.

On the other hand, after being suppressed by the mold member 5.6, the molded part 21 is cooled from both surfaces due to the temperature difference between the mold member and the molded part 21, increasing its viscosity and stabilizing its surface shape.

Next, as shown in FIG. 6, the guide block 13 is operated to return the first mold member 5 to its original state. The operation start time is set to 6, the operation path r period is set to T7,
If the start time of operating the cutting ring 7 to its original state is at the same time as the return end time of the first mold member 5 or after its end, the part to be formed 21 is being held by the cutting ring 7;
It will not fall naturally.

The part to be formed, that is, the molded product 23, is taken out at the same time as the return of the cutting ring 7 is completed ('r'', l).This can be done using a well-known suction hand or the like. After that, the second mold member 6 is returned to its original state.In FIG. 8, the return start time of the second mold member 6 is T, and the return end time is Too.

As shown in No. 7M, when taking out the molded product 23, the molded product 23 is released from the holding state of the cutting ring 7 by not pushing out the mold member 6 in the direction of the molded member 5, and the molded product 23 is removed. It may also be designed to facilitate removal.

In the second operation, the press molding by the molding die 5.6 is performed on the tip of the glass fluid 2, that is, the portion excluding the cut marks 3, so the resulting molded product 23 may have shear marks, etc. No surface defects occur.

The volume of the cavity formed by the mold parts 5.6 can be set by the stroke of a cylinder, not shown, which exerts a restraining action on the respective mold part. That is, the set stroke of the cylinder determines the shortest approach width between the mold members 5.6 during compression, which regulates the distance between the molding surfaces of the mold members 5.6.

In addition, in this embodiment, the guide bin 15 and the guide hole 1
The mold member 5.6 is pushed by the guide member composed of 6.
Since the E motion is guided and the axis misalignment of these mold members 5 and 6 is corrected, the manufactured molded product 23 has a highly accurate optical axis. The device can be used together.

In addition, 1) The heating means of the heater 32.3:3, the thermocouple 34.35 for temperature control, and the controller (not shown) eliminate pitch fluctuations between the guide member sets IIg due to variations in thermal expansion. The fitting and sliding movements of these guide members are performed smoothly.

Furthermore, the surface shape and properties of the molded product 23 are determined by each mold member 5.
It is determined by the respective molding surfaces 5a and 6a of 6. Molded product 23
The outer circumferential shape of the molded product 21 is determined by the inner circumferential shape of the cutting ring 7, and the outer circumference of the molded product 21 is formed simultaneously with the cutting operation of the cutting ring 7.

The press molding apparatus described below uses a mold that performs pressing operations from left and right directions in response to a nozzle through which glass fluid, which is a molding material, flows downward. The present invention is not limited to a straight flow type and mold, but it is also possible to use a mold configured for glass fluid supplied laterally or obliquely, for example.

(Effects of the Invention) As explained in 1, according to the present invention, the initial distance between the mold and the blade head of the cutting member is reduced, without being affected by the thermal expansion of the mold. It is possible to prevent the cutting member from galling or biting against the mold, and to perform a circular molding operation.

Moreover, the outer periphery of the molded product obtained by such a molding apparatus is free from roughness and no occurrence of flakes or the like.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a press molding apparatus i'1 showing an embodiment of the present invention. FIGS. 2 to 7 are sectional views of essential parts of a molding apparatus showing an example of application of the apparatus shown in FIG. 1, and show the operating state of the apparatus in the order of steps. FIG. 8 is a diagram showing a timing chart of each operating section of the press molding apparatus shown in FIG. 1. l... Nozzle 2... Glass fluid 4... Cutting blade 5... First mold its material 6... Second mold member 7... Cutting ring 7a... Blade head 21 ... Molded part 22 ... Cut pieces 2 pieces 3 ... Molded product 24 ... Slight gap 25 ... Cutting ring heating heater 26 ... Cutting ring temperature measurement thermocouple 27 ... Distance between cutting ring and mold 32.33... Heater agent in guide block Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 and Figure 7

Claims (1)

[Claims] A cutting member for cutting the excess portion of the glass material at a predetermined interval is provided on the outer periphery of a mold for press-molding a molten glass material, and the cutting member is connected to the mold at the inner periphery of the blade head of the cutting member. 1. A molding apparatus for an optical element, characterized in that a predetermined distance between the cutting member and the member is a slight gap, and heating means capable of temperature control is disposed within the cutting member so as to maintain the gap at a predetermined amount.