JP2006256917A - Glass forming device and glass forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass forming device capable of easily and surely peeling a glass lens adhered to a forming die. <P>SOLUTION: In the glass forming device, the glass forming device for forming a glass lens 3A from a glass raw material by the relative movement of an upper die 1 and a lower die 2 being a pair of dies has a mold-release ring 4 fitting and sticking to the upper die 1, and the mold-release ring 4 has a tapered surface 4a forming a peripheral part 3a of the glass raw material, and when the glass raw material reaches a moldable temperature, the ring relatively moves to the moving direction to the lower die 2 together with the upper die 1 and the glass lens 3A is press-molded from the glass raw material, thereafter, the molded glass lens 3A becomes below a transition temperature at a cooling process and the mold-release ring 4 is heat shrunk and since the tapered surface 4a finely moves to relatively inner diameter side to the upper die 1, the peripheral part 3a of the glass lens 3A is pressurized by the movement and the glass lens 3A adhered to the upper die 1 is peeled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a glass forming apparatus and a glass forming method for forming a glass material by relative movement of a pair of molds.

  2. Description of the Related Art Conventionally, there is a glass molding apparatus that manufactures an optical element (glass molded body) such as a glass lens by press molding in a state where an optical material, which is a glass material, is heated and softened by a molding die having a mirror-finished molding surface. In the glass molding apparatus, it is important that the molded optical element cooled to a predetermined temperature is stably and reliably released from the mold, and the released optical element can be carried out by an autoloader.

The molding apparatus for press molding (glass molding apparatus) disclosed in Patent Document 1 can mold an optical element with high molding accuracy, and can mold the optical element in a stable state after molding. It is. In this molding apparatus, forcible mold release means is provided for pressing and releasing the peripheral edge portion of the optical element that is in close contact with the upper mold side after molding. The forced release means is attached to the upper mold in a state of being biased via a spring member as an elastic member, and presses the optical element by the biasing force of the spring member when the mold is opened. , To release. The spring member can be of various spring shapes, but it is necessary to use a heat-resistant material that can withstand the temperature at which glass can be formed, for example, ceramics such as zirconia.
Patent document 1 is Unexamined-Japanese-Patent No. 2004-196636.

  However, the spring member incorporated in the forced release means of the above-described press molding molding apparatus of Patent Document 1 is an expensive spring member having high heat resistance, and the optical element is used as a required biasing force. It is required to have a strong biasing force enough to pull it away from. For example, when the outer diameter of the optical element is about 10 mm, a static pressure of about 8 N acts on the optical element, and in order to release the optical element reliably, the optical element is contracted. It is necessary to press the optical element with a very large release force obtained by adding the adsorption force. Accordingly, the outer diameter of the spring member is increased, and the molding apparatus is increased in size. At the same time, expensive members are used.

  The present invention has been made to solve the above-described problems, and a glass molding apparatus or a glass molding method capable of easily and reliably peeling a glass molded body attached to a mold. The purpose is to provide.

  The glass forming apparatus according to claim 1 of the present invention is a glass forming apparatus for forming a glass material by relative movement of a pair of molds, and has a release member, and the release member is the pair of molds. When the temperature reaches a temperature at which the glass material can be molded, the glass molded body formed from the glass material can be moved at a transition point. When it becomes below, the said glass molded object is pressed by heat shrink, and the said glass molded object adhering to said one type | mold is peeled.

  A glass forming apparatus according to a second aspect of the present invention is the glass forming apparatus according to the first aspect, wherein the release member has a tapered portion, and the pair of molds are formed with each other for glass molding. In the close mold closed state, the taper portion of the release member and the glass molded body are in contact with each other, and when the glass molded body is below the transition point, the taper portion of the mold release member becomes the glass molded body. It will be in the state which presses.

  The glass molding method according to claim 3 of the present invention is a glass molding method in which a glass material is molded by a pair of molds, and a release member fitted to one mold of the pair of molds is expanded by thermal expansion, The heated glass material is pressed with the pair of molds in a movable state with respect to the one mold to form a glass molded body. The release member presses the glass molded body and peels off the glass molded body attached to the one mold.

  The glass molding method according to claim 4 of the present invention is the glass molding method according to claim 3, wherein the pair of molds are in a mold-closed state in which the molds are close to each other for glass molding. The glass molded body is in contact with the glass molded body, and when the glass molded body is below the transition point, the release member presses the glass molded body.

  According to the present invention, it is possible to provide a glass molding apparatus or a glass molding method capable of easily and reliably peeling a glass molded body attached to a mold.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a main part of a glass forming apparatus according to an embodiment of the present invention. 2 and 3 are cross-sectional views of the main part around the mold showing the state before and after the forming operation in the glass forming apparatus, FIG. 2 shows the state before forming, and FIG. 3 shows the press forming state. 4 (A) to 4 (B) are cross-sectional views of the main part around the mold showing the molding and mold release operation states in the glass molding apparatus, and FIG. 4 (A) is immediately after the press molding in the mold closed state. 4B shows a state during the mold release operation in the mold open state, and FIG. 4C shows a state after the mold release.

  The glass forming apparatus 20 of the present embodiment heats and softens the glass material (optical material) 3, presses it with a pair of molds, opens the pair of molds after cooling, and has a desired surface shape. This is a molding apparatus to which a glass molding method for obtaining a body glass lens 3A can be applied. As shown in FIG. 1, the glass forming apparatus 20 includes an upper die 1 and a lower die 2 that are a pair of forming dies, and a release ring 4 that is a release member supported by the upper die 1. A sleeve 5 that covers the upper mold 1 and the lower mold 2, an upper shaft 6 that supports the upper mold 1, a lower shaft 7 that supports the lower mold 2, an upper mold 1, a lower mold 2, and a sleeve 5. A plurality of infrared lamp heaters 11, which are one of the heat sources for mold heating, a closed furnace 8, a base plate 9, a servo motor that is supported by a frame (not shown) and moves the upper shaft 6 in the vertical direction, or And a driving device 10 composed of an air cylinder.

  The fitting portion between the driving device 10 and the closed furnace 8 is fitted through an O-ring 16 for sealing, and the driving device 10 is movable in the vertical direction with respect to the closed furnace 8. .

The upper mold 1 and the lower mold 2 are materials having sufficient strength in a temperature range sufficient to form the glass lens 3A from the glass material 3, and are formed of cemented carbide or SIC, and the linear expansion coefficient thereof. Is approximately 4.8 × 10 ⁻⁶ / ° C. in the case of cemented carbide and 4.0 × 10 ⁻⁶ / ° C. in the case of SIC. The convex molding surface 1a of the upper mold 1 and the concave molding surface 2a of the lower mold 2 are mirror surfaces. Further, inside the upper mold 1 and the lower mold 2, cartridge heaters 12 and 13, which are heat sources for heating the mold, and thermocouples 14 and 15 for detecting the mold temperature are embedded.

The release ring 4 is a ring-shaped member and is made of a cemented carbide having a sufficient strength in a temperature range sufficient to form the glass material 3. The linear expansion coefficient is a value larger than that of the upper die 1 and is 5.4 to 6.8 × 10 ⁻⁶ / ° C. The release ring 4 has an upper end fitted into and fixed to the shaft portion of the upper mold 1, and a circular shape around the upper portion of the convex molding surface 1 a of the upper mold 1 at the lower portion of the release ring 4. An opening is arranged. When the upper die 1 and the release ring 4 are inflated and contracted, the inner diameter tip portion 4c of the opening portion is located with respect to the upper side of the convex molding surface 1a of the upper die 1 as shown in FIGS. It does not abut and is located close together.

  The release ring 4 is formed with a tapered surface 4a which is a conical inner surface tapered portion inclined downward from the opening inner diameter front end portion 4c toward the lower surface side outward. That is, the taper surface 4a forms a taper surface that is opposite to the convex molding surface 1a along the periphery of the convex molding surface 1a of the upper mold 1. When the glass material 3 is press-molded with the upper mold 1, the peripheral upper surface of the glass material 3 is pressed by the tapered surface 4a, and the peripheral portion 3a of the glass material 3 (glass lens 3A) is formed in a shape along the tapered surface 4a. The It is necessary to set the pressing amount of the glass material 3 by the tapered surface 4a so that the inner diameter side of the formed peripheral edge portion 3a does not bulge upward above the inner diameter tip portion 4c of the release ring 4. This is because the taper surface 4a does not interfere with the glass lens 3A and the tapered surface 4a does not interfere with the glass lens 3A when the mold release ring 4 tries to contract toward the inner diameter side during the mold release operation described later. This is to enable relative movement to the inner diameter side.

  Further, a cylindrical portion is formed between the upper die fixing portion on the upper end side of the release ring 4 and the opening portion, and the inner peripheral surface 4b interferes with the shaft portion of the upper die 1 when contracted. It is inserted into the shaft portion of the upper mold 1 with a gap that does not allow. Therefore, when the upper mold 1 and the release ring 4 are cooled after being molded, the portions other than the fixed portion between the upper mold 1 and the upper mold 1 can be contracted and deformed without interfering with the upper mold 1.

  The upper shaft 6 is driven by the driving device 10 to move the upper mold 1 in the downward direction D1 or the upward direction D2. The upper end of the upper shaft 6 has a larger diameter than the fitting portion of the closed furnace 8, and when the drive device 10 is raised, it is caught by the fitting portion of the closed furnace 8, the closed furnace 8 is raised, and the drive device 10 is lowered. Then, after the closed furnace 8 is placed on the base plate 9, it is not affected by the lowering operation of the driving device 10.

  The lower shaft 7 is fixedly supported on the upper part of the base plate 9 of the main forming apparatus 20. Each of the upper shaft and the lower shafts 6 and 7 is provided with a cooling path (not shown) through which pure water that is a coolant for mold cooling can flow.

  The sleeve 5 is formed of a cylindrical ceramic material, the upper part is fixed to the upper mold 1, and the sleeve 5 is precisely fitted (with a very small gap of 5 μm or less) and is slidable with respect to the lower mold 2. Precise fitting (very small state with a gap of about 5 μm). Accordingly, the irradiation heat from the infrared lamp heater 11 is efficiently transmitted to the upper mold 1 and the lower mold 2 through the sleeve 5.

  The cartridge heaters 12 and 13 heat the upper mold 1 and the lower mold 2 by heat conduction. And the glass raw material 3 is heated through the said type | mold.

  The infrared lamp heater 11 is fixedly supported on the inner wall of the closed furnace 8 and is located along the outer periphery of the sleeve 5.

  The cartridge heaters 12 and 13 and the infrared lamp heater 11 and the refrigerant are controlled by a control unit (not shown) of the molding apparatus 20 based on the mold temperature detected by the thermocouples 14 and 15, and the glass material 3 at each step. And the temperature control of the upper and lower molds 1 and 2 is performed.

  The closed furnace 8 is a furnace capable of sealing or opening the surrounding space of the upper mold 1, the lower mold 2 and the sleeve 5 so as to be filled in a vacuum or a non-oxidizing atmosphere when being sealed during molding. Each contact portion is sealed. In addition, a gas exhaust port and an introduction port are provided. During molding, the inside of the furnace can be evacuated and non-oxidizing gas can be introduced through the exhaust port and the introduction port.

  The glass lens 3A is, for example, a glass molded body formed of a glass material 3 such as lanthanum glass, and is a meniscus lens having an aspheric concave shape on the upper surface side and an aspheric convex shape on the lower surface side. . The glass material 3 is processed in advance into an approximate shape of the glass lens 3A by grinding and polishing.

  A process of molding and releasing the glass lens 3A by the glass molding apparatus 20 having the above-described configuration will be described with reference to FIGS. 2, 3, 4 (A) to 4 (C).

  First, the glass material 3 is conveyed by an autoloader (not shown) and placed on the lower mold 2. And the sealing furnace 8 is made into a sealing state.

  The upper mold 1 is lowered in the direction D1, and when the convex molding surface 1a of the upper mold 1 reaches the vicinity of the surface of the glass material 3, the upper mold 1 is temporarily stopped (FIG. 2). Therefore, the inside of the closed furnace 8 is evacuated and replaced with nitrogen gas which is a non-oxidizing gas. Then, the cartridge heaters 12 and 13 and the infrared lamp heater 11 are energized under the control of the control unit of the glass forming apparatus 20, and the upper mold 1, the release ring 4, the lower mold 2, the sleeve 5, and the glass material. Start heating 3. When the target temperature (temperature exceeding the glass material transition point, for example, 500 ° C to 600 ° C) is reached, the upper mold 1 is lowered again in the D1 direction to close the mold, and the convex molding surface 1a and concave molding are performed. The glass material 3 is pressed by the surface 2a. Then, after a predetermined amount of pressing, energization of the cartridge heaters 12 and 13 and the infrared lamp heater 11 is stopped. On the other hand, the cooling process is started by passing pure water as a refrigerant through the cooling path, and cooling of the mold is started. Due to the cooling, the heat of the upper and lower molds and the glass lens is released out of the system through the refrigerant. The glass material 3 is press-molded to have the shape of the glass lens 3A. Further, on the upper peripheral edge of the glass lens 3 </ b> A, the peripheral edge 3 a is formed by being pressed by the tapered surface 4 a of the release ring 4.

  3 and 4A show a state where the press forming of the glass material 3 is completed in the above-described mold closed state (heated state). In this state, the convex molding surface 1a of the upper mold 1 and the taper surface 4a of the release ring 4 are both expanded in the outer peripheral direction by the temperature rise, and the difference δ in the expansion amount is the above-described upper mold 1. This is an amount proportional to the difference in linear expansion coefficient between the mold and the release ring 4, and the release ring 4 expands to the outer diameter side.

  When the upper and lower mold temperatures are lowered to a predetermined temperature (below the transition point), the pressing is finished, and the upper mold 1 is raised by the driving device 10 to perform mold opening. The distance is less than the distance by which the mold 1 is lowered, and the closed furnace 8 is not lifted by the upper end portion of the upper shaft 6. In this state, as shown in FIG. 4B, the glass lens 3 </ b> A moves upward together with being temporarily attached to the upper mold 1. This phenomenon occurs because the convex molding surface 1a, which is the mirror surface of the upper mold 1, is more strongly adsorbed by the concave action of the glass lens 3A.

  After the press molding in FIG. 4A, the glass lens 3A, the convex molding surface 1a of the upper mold 1 and the tapered surface 4a of the release ring 4 contract during the cooling period in the mold open state in FIG. 4B. However, the amount of contraction is an amount corresponding to the amount expanded by the above-described press molding, and the taper surface 4a of the release ring 4 is the amount of expansion described above with respect to the convex molding surface 1a of the upper mold 1. A relatively small amount of relative movement is made in the inner diameter direction by a contraction amount difference corresponding to the difference δ. Thus, when the taper surface 4a moves relative to the convex molding surface 1a toward the inner diameter side, the glass lens 3A receives a downward pressing force in the mold release direction via the peripheral edge portion 3a. This pressing force is a strong force that deforms the release ring 4 by the difference in contraction amount, and is a force sufficient to release the glass lens 3 </ b> A from the upper mold 1.

  At this time, the upper mold 1 and the release ring 4 contract in the axial direction, but since the cooling is performed from the upper and lower molds 1 and 2, the upper and lower molds 1 and 2 contract first. The contraction of the release ring 4 is delayed. Therefore, the pressing force in the mold release direction to the glass lens 3A by the tapered surface 4a further acts.

  The glass lens 3A is released from the upper mold 1 by the pressing force due to the contraction action described above as shown in FIG. 4C after being left for a predetermined time in the mold open state of FIG. Falls on the concave molding surface 2a. Thereafter, when the mold temperatures of the upper and lower molds 1 and 2 are lowered to a temperature at which the molds are not oxidized (200 ° C.), the upper shaft 6 is raised by the driving device 10 and the sealed furnace 8 is hooked at the upper end portion of the upper shaft 6. lift. The glass lens 3A is taken out by an autoloader (not shown).

  According to the glass molding apparatus 20 of the present embodiment described above, the mold can be easily and reliably released from the upper mold 1 without applying an impact or a pulling external force to the molded glass lens 3A. Product yield and productivity can be improved.

  In the glass forming apparatus 20 of the present embodiment, the upper mold 1 side is a movable mold, but not limited to this, the upper mold 1 side is a stationary mold, the lower mold 2 side is a movable mold, and the other configurations are the same. It is also possible to apply.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent elements are deleted from all the constituent elements shown in each embodiment, the problems described in the column of problems to be solved by the invention can be solved, and the effects described in the effects of the invention can be achieved. In the case of being obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

  The glass forming apparatus or the glass forming method according to the present invention can be applied as a glass forming apparatus or a glass forming method capable of easily and reliably peeling the glass formed body attached to the forming die.

It is sectional drawing which shows the principal part of the glass forming apparatus which is one Embodiment of this invention. It is principal part sectional drawing of the mold periphery in the state before shaping | molding in the glass shaping | molding apparatus of FIG. It is principal part sectional drawing of the mold periphery in the state after the press molding in the glass forming apparatus of FIG. FIG. 4 is a cross-sectional view of the main part around the mold showing the molding and mold release operation states in the glass molding apparatus of FIG. 1, and FIG. 4 (A) shows the mold closed state immediately after the press molding, (B) shows a state during the mold release operation in the mold open state, and FIG. 4 (C) shows a state after the mold release.

Explanation of symbols

1 ... Upper mold (a pair of molds, one mold)
2 ... Lower mold (a pair of molds)
3 ... Glass material 3A ... Glass lens (glass molding)
4 ... Release ring (release member)
4a: Tapered surface (tapered portion)

Agent Patent Attorney Susumu Ito

Claims (4)

In a glass forming apparatus that forms a glass material by relative movement of a pair of molds,
A glass molding that is fitted to one of the pair of molds and is movable relative to the one mold when the glass material reaches a moldable temperature, and is molded from the glass material. A glass forming apparatus comprising a release member that peels off the glass molded body attached to the one mold by pressing the glass molded body by thermal contraction when the body is below the transition point. The release member has a tapered portion, and the taper portion of the release member and the glass molded body are in contact with each other when the pair of dies close to each other for glass molding. The glass forming apparatus according to claim 1, wherein the taper portion of the release member presses the glass formed body when the glass formed body is below a transition point. In a glass forming method of forming a glass material with a pair of molds,
The mold release member fitted to one of the pair of molds expands due to thermal expansion, and the heated glass material is pressed by the pair of molds in a state where it can move relative to the one mold. When the glass molded body is below the transfer point, the release member presses the glass molded body by thermal shrinkage and peels the glass molded body attached to the one mold. A glass forming method characterized by the above. The mold release member and the glass molded body are in contact with each other in a mold closed state where the molds are close to each other due to glass molding, and the mold release member when the glass molded body is below the transition point. The glass forming method according to claim 3, wherein the glass forming body is pressed.

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