WO2008053860A1

WO2008053860A1 - Mold press forming die and molded article manufacturing method

Info

Publication number: WO2008053860A1
Application number: PCT/JP2007/071068
Authority: WO
Inventors: Kouichi Satou; Xuel Zou
Original assignee: Hoya Corporation
Priority date: 2006-10-31
Filing date: 2007-10-30
Publication date: 2008-05-08
Also published as: JP5059019B2; JPWO2008053860A1; CN101528616A; CN101528616B; KR101314440B1; KR20090082375A

Abstract

A molded article is highly accurately press-formed by extremely facilitating horizontal shift of a forming die on a die holding member and highly accurately maintaining an upper die and a lower die coaxial. The mold press forming die is provided with a pair of upper and lower dies (10, 20) having forming surfaces (11, 21) in discretionary shapes; a body die (30) wherein the upper and lower dies (10, 20) are coaxially inserted with their forming surfaces (11, 21) facing each other; a lower die holding member (25) for holding the lower die (20) by permitting the lower die to move in the horizontal direction; and a plurality of rolling members (60) which are arranged between the lower die (20) and the lower die holding member (25) and roll with shift of the lower die (20) in the horizontal direction.

Description

Specification

Mold press mold and method for producing molded body

Technical field

[0001] The present invention includes a pair of molds having a molding surface of an arbitrary shape, and a barrel mold in which these molds are arranged so as to face each other so that the molding surfaces face each other and are inserted coaxially, etc. With regard to mold press molds for press molding of molding materials, especially in molds such as optical elements that prevent eccentricity (shift [shift] and tilt Ktilt) when the mold is closed! / The present invention relates to a mold press mold that can press-mold a molded body that requires shape accuracy, and a method for producing a molded body using such a mold press mold.

Background art

[0002] As a method of manufacturing an optical element such as an aspherical lens using a glass material, it is heated and softened by a pair of molds having molding surfaces facing each other corresponding to the shape of the molded product to be obtained. A mold press method is known in which a molding material is pressed and the molding surface of these molds is transferred.

In addition, the mold and the molding material were preheated separately and preheated separately to prevent high-temperature deterioration of the molding surface of the mold used to carry out the mold press method and to shorten the molding cycle time. A method is known in which a molding material is introduced into a mold and press molding is performed immediately.

[0003] These methods are disclosed in Patent Document 1, for example. In the method disclosed in Patent Document 1, the glass material and the mold are preheated, and after the glass material is supplied to the lower mold, the upper and lower molds are immediately closed to perform press molding. Then, the mold is cooled to below the glass transition point, the mold is opened, and the glass molded body is taken out. According to such a method, it is possible to form a glass molded body with excellent surface accuracy while shortening the cycle time and maintaining productivity.

[0004] Here, the clearance between the body mold and the sliding surfaces of the upper and lower molds guided thereby is set narrow so that the upper and lower molds are coaxial with high accuracy. For this reason, when the mold is closed during press molding, rubbing and galling occurs in the sliding part between the body mold and the upper and lower molds, and proper press operation is achieved. May be disturbed.

[0005] In Patent Document 2, in order to make one of a pair of molds slidable in a direction perpendicular to the mold closing and mold opening direction, and to reduce the sliding resistance, a lower mold and a lower mold support base are provided. There is disclosed a mold in which a sliding surface is lubricated. With this configuration, when the lower mold is inserted into the body mold when the mold is closed, the position is corrected so that the lower mold easily moves in the horizontal direction and is coaxial with the upper mold. For this reason, it is said that it is possible to prevent excessive force from acting on the upper and lower molds and the body mold, and to avoid rubbing and galling between them.

[0006] Patent Document 1: Japanese Patent Laid-Open No. 11 171564

Patent Document 2: JP 2006-83026 A

Disclosure of the invention

Problems to be solved by the invention

[0007] Currently, optical elements used for small imaging devices and optical pickups have very high optical performance requirements. In order to produce a molded product that meets these requirements by mold press, the eccentric accuracy of the upper and lower molds, that is, good coaxiality and low relative inclination, must be kept extremely high throughout the continuous pressing process. Is required. For example, the horizontal displacement (shift) between the upper mold and the lower mold is within 10 m, preferably within 5 111, and the tilt angle is within 5 minutes, preferably within 2 minutes. It is required to be. Therefore, the clearance allowed between the barrel mold and the upper and lower molds is at most lO ^ m, and in this situation, the upper and lower molds must be continuously approached reliably.

[0008] However, it is generally difficult to perform continuous press several hundreds to tens of thousands of times while maintaining such narrow sliding / clearance sliding. In particular, in the method disclosed in Patent Document 1, since the mold in the mold open state is preheated and the mold is closed in the preheated state, it is more difficult to maintain the coaxiality of the upper and lower molds. That is, the upper mold and the lower mold are each supported by a support member, and either one is fixed to the main shaft of the mold closing mechanism so as to be movable up and down. In this state, if the upper die and the lower die are preheated to a temperature suitable for press molding, the upper and lower die support members are thermally expanded and thermally deformed. For example, when the molding material is glass, it is preheated to a high temperature of 400 ° C to 900 ° C, so in this state, while maintaining high eccentric accuracy of the upper and lower molds, several hundred to several 10,000 continuous presses It is extremely difficult to do.

[0009] Further, in order to improve the production efficiency, as disclosed in Patent Document 1, it is desirable to support a plurality of upper molds and lower molds and simultaneously perform a plurality of press moldings.

However, when such an apparatus is used, the upper and lower molds are slightly displaced due to thermal deformation of the support member or the like. The amount of displacement varies depending on the distance of each mold from the press spindle, and also varies depending on the press temperature selected depending on the type of molding material. Furthermore, if a plurality of upper and lower molds are supported by a single upper mold support member and a lower mold support member, the upper and lower support members support a single mold! / Because the dimensions are larger than / !, thermal deformation is also large. For this reason, it is extremely difficult to maintain a state in which the upper and lower molds arranged there are close and in close contact with each other with their axes accurately aligned through a continuous pressing process.

[0010] In mold press molding, if the coaxiality of the mold is not accurately maintained, rubbing or galling occurs between the lower mold and the barrel mold. A large load is applied during pressing, so if scuffing occurs, force is applied to the molded body, the load to be applied is absorbed between the body mold and lower mold, and the press pressure acts unevenly on the molded body, causing eccentricity. Deterioration of accuracy, surface accuracy, wall thickness accuracy, and damage to the body and lower molds.

In addition, when the abrasion powder generated by rubbing or galling adheres to the molded body, the molded body has a poor appearance. Further, when such rubbing or galling occurs, the clearance between the body mold and the lower mold exceeds a predetermined range, and as a result, the position regulation of the lower mold by the body mold becomes loose. This means that the coaxiality of the upper mold and the lower mold is lost, and a horizontal shift (shift) between the upper mold and the lower mold and a relative inclination (falling) between the upper mold and the lower mold occur. . In particular, when the molded body is an optical element, serious performance deterioration occurs.

Here, in Patent Document 2, the sliding surface between the lower mold and the lower mold support member is lubricated to facilitate the horizontal movement of the lower mold and prevent rubbing and galling between the body mold and the lower mold. /!

However, sliding is repeated on the sliding surface between the lower mold and the lower mold support member every press molding, and as the number of press molding increases, the sliding surface deteriorates and wears, and is regularly lubricated. Processing must be done. In addition, when the lower die is inserted into the barrel die, the lower die and the lower die support member are surely easy to make the horizontal movement of the lower die easier due to the lubrication treatment on the sliding surface. Because of the surface contact, the initial moment required for horizontal movement becomes relatively large, and the horizontal movement of the lower mold may not always be performed smoothly.

[0012] The present invention has been made in view of the above circumstances, and in order to press-mold the molded body with high accuracy, the horizontal movement of the mold relative to the mold holding member is extremely facilitated, and thus The purpose of the present invention is to provide a mold press mold capable of stably producing a high-precision molded body, and a method for producing a molded body using such a mold. .

Means for solving the problem

[0013] The mold press mold of the present invention includes a first mold and a second mold having a molding surface of an arbitrary shape, and the first and second molds facing each other so that the molding surfaces face each other. A barrel mold that is inserted coaxially, a first mold holding member that holds the first mold movably in the horizontal direction, and a gap between the first mold and the first mold holding member. And a plurality of rolling members that roll with the movement of the first mold in the horizontal direction.

[0014] According to the mold press mold according to the present invention configured as described above, a plurality of rolling members are disposed between the first mold and the first mold holding member, so that the first The moving force in the horizontal direction can be made smooth even if a small initial moment occurs. For this reason, when the press molding operation is started and the first die is inserted into the barrel die, the axis of the first die does not coincide with the axis of the second die and the barrel die. However, the first mold moves smoothly in the horizontal direction while being inserted into the body mold, so that the first mold that does not exert excessive force on the first mold or the trunk mold is Guided to a position that is coaxial with the second and barrel molds. Therefore, even if the clearance between the first mold and the second mold and the trunk mold is set to about several microns, the first mold and / or the second mold can be surely and smoothly inserted into the trunk mold. The coaxiality of the first and second molds can be highly secured.

[0015] In the mold press mold according to the present invention, a guide portion having a tapered diameter is formed on the inner peripheral surface of the opening of the cylinder die on the side where the first die is inserted. The guide portion guides the first mold so that the first mold is coaxial with the second mold when the first mold is inserted into the body mold. It can be set as the structure to do. With such a configuration, the first mold is smoothly inserted into the trunk mold while being guided by the guide portion that does not prevent the insertion of the first mold into the trunk mold, and the first mold Force the horizontal movement of the mold with force S.

[0016] Further, in the mold press mold according to the present invention, the rolling member may be a spherical member having a uniform diameter.

With such a configuration, the spherical member having a uniform diameter disposed between the first mold and the first mold holding member is in a point contact with both, and the first mold is smoothly smoothed. Since the horizontal movement is promoted, the first mold can be smoothly inserted into the body mold.

[0017] Further, in the mold press mold according to the present invention, the rolling member may be made of a ceramic having a bending strength at a press molding temperature of 300 MPa or more. Therefore, when press-molding a molding material such as optical glass, the rolling member has strength that does not cause deformation or wear even when subjected to a press load at a high temperature. High mold press molding can be maintained.

[0018] Also, in the mold press mold according to the present invention, the rolling member is made of any force selected from silicon nitride, silicon carbide, zirconium carbide, and alumina.

With such a configuration, all the rolling members made of the above materials are excellent in strength (bending strength) and hardness (Vickers hardness) at high temperatures, so that high-precision mold press molding can be maintained over a long period of time. can do.

[0019] Further, the mold press mold according to the present invention includes the rolling member on at least one surface of the first mold and the first mold holding member facing each other through the rolling member. It can be set as the structure which formed the recessed part which accommodates this.

By adopting such a configuration, the rolling member can be prevented from falling off when assembling the mold by assembling the rolling member in the recessed portion.

[0020] Further, the mold press mold according to the present invention includes an elastic member that biases the body mold toward the first mold, and press-molds the molding material with the first and second molds. In this case, the opening end face of the body mold on the side where the first mold is inserted is configured to be pressed against a part of the first mold by the urging force of the elastic member. it can. With such a configuration, at the time of press molding, the end surface of the opening of the barrel mold is pressed against the first mold by the urging force of the elastic member, and the positional relationship between the first mold and the barrel mold, particularly the coaxiality Is correctly defined, and a molded article having excellent eccentricity accuracy can be obtained.

[0021] Further, in the mold press mold according to the present invention, the first mold has a convex surface on the molding surface, and is positioned around the molding surface of the first mold. A retraction mechanism that retreats the support member from the periphery of the molding surface of the lower mold in accordance with the proximity movement of the first and second molds, and a support member that supports the molding material supplied on the molding surface It can be set as the structure provided with these.

With such a configuration, even when a meniscus lens having a concave surface or a biconcave lens is to be molded, it is possible to perform press molding with high accuracy without causing an uneven thickness that causes the molding material to deviate significantly from the center. it can.

[0022] In the mold press mold according to the present invention, an interposed member having a curved surface that comes into contact with the first mold holding member is interposed between the first mold holding member and the rolling member. It can be set as the structure.

With such a configuration, it is assumed that the first mold is inclined with respect to the trunk mold, and the interposed member corrects the inclination of the first mold while swinging along the curved surface. Therefore, since the first mold is inserted into the barrel mold with a high degree of coaxiality by correcting the inclination by the interposition member and horizontally moving, the eccentricity (tilt and shift accuracy) is good. A compact can be formed.

[0023] Further, in the method for producing a molded body according to the present invention, the first and second molds having a molding surface having an arbitrary shape and the first and second molds are so that the molding surfaces face each other. A cylindrical mold with a guide portion formed on the inner peripheral surface of the opening on the side where the first mold is inserted, and the first mold can be moved in the horizontal direction. A mold press molding die comprising: a first die holding member held on the first die; and a plurality of rolling members disposed between the first die and the first die holding member; The mold press molding heated to a predetermined temperature by the heating means using a molding apparatus comprising: a driving means for moving up and down at least one of the second mold; and a heating means for heating the mold press mold. The molding material is press-molded with a mold, and the shape of the molding surface is KiNaru In manufacturing a molded body by transferring to a shape material, the first mold is inserted into the barrel mold by raising and lowering at least one of the first and second molds by the driving means, At this time, as the first die contacts the guide portion formed on the barrel die and moves in the horizontal direction, the rolling member rolls, and the first die is moved to the second die. This is a method of guiding so as to be coaxial with the mold.

By adopting such a method, smooth horizontal movement of the first mold is promoted by rolling the rolling member as the first mold moves in the horizontal direction by the guide part of the trunk mold. Is done. Accordingly, since the pair of first and second molds facing each other can be maintained in the coaxial state with high accuracy, the molded body can be manufactured with high accuracy.

[0024] Further, the method for producing a molded body according to the present invention more specifically preheats the molding material prior to press molding, preheats the mold press molding die, and uses the molding material. The force S is used as a method of performing press molding by supplying the preheated mold press mold.

By adopting such a method, it is possible to produce a high-precision molded body that shortens the cycle time and increases the production efficiency.

The invention's effect

[0025] As described above, according to the present invention, by disposing a plurality of rolling members between the first mold and the first mold holding member, the first mold in the horizontal direction is arranged. It is possible to make the movement smooth. For this reason, when the press molding operation is started and the first mold is inserted into the body mold, the axial force S of the first mold coincides with the axis of the second mold and the moon mold. Even if it is not, the first mold moves smoothly in the horizontal direction while being inserted into the trunk mold, so that the first mold does not exert excessive force on the first mold or the trunk mold. However, it is guided to a position that is coaxial with the second mold and the trunk mold, so that the coaxiality of the first and second molds can be highly secured.

In addition, since the rolling member rolls as the first die moves in the horizontal direction, the rolling member does not wear even if it is repeatedly press-molded. Continuous production is possible.

Brief Description of Drawings FIG. 1 is a cross-sectional view schematically showing a first embodiment of a mold press mold according to the present invention.

FIG. 2 is a cross-sectional view schematically showing a first embodiment of a mold press mold according to the present invention.

FIG. 3 is a cross-sectional view schematically showing a first embodiment of a mold press mold according to the present invention.

FIG. 4 is a cross-sectional view showing an outline of a second embodiment of a mold press mold according to the present invention.

FIG. 5 is a cross-sectional view schematically showing a third embodiment of a mold press mold according to the present invention.

FIG. 6 is a cross-sectional view schematically showing a fourth embodiment of a mold press mold according to the present invention.

FIG. 7 is a sectional view schematically showing a fifth embodiment of a mold press mold according to the present invention.

FIG. 8 is a schematic plan view showing an example of a press molding apparatus suitable for press molding with the mold press mold according to the present invention.

FIG. 9 is a cross-sectional view showing the outline of another embodiment of the mold press mold according to the present invention. FIG. 10 is a cross-sectional view showing the outline of still another embodiment of the mold press mold according to the present invention. is there.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Mold Press Mold / First Embodiment]

First, a first embodiment of a mold press mold (hereinafter referred to as “mold”) according to the present invention will be described.

1, 2 and 3 are cross-sectional views schematically showing the mold according to the present embodiment. In these drawings, FIG. 1 shows a state in which a molding material G made of optical glass or the like is supplied to a mold that has been opened. Fig. 2 shows the state during the press forming operation. Fig. 3 shows the closed state.

[0029] The mold according to the present embodiment is an upper mold (first mold) in which molding surfaces 11 and 21 having arbitrary shapes are formed based on the shape of an optical element (molded body) such as a glass lens to be molded. A second mold) 10 and a lower mold (first mold) 20. These molding surfaces 11 and 21 can be, for example, spherical surfaces or aspherical surfaces constituting the first and second surfaces of the glass lens. The upper mold 10 and the lower mold 20 are arranged so that the upper and lower molds 10 and 20 arranged so as to face each other with the molding surfaces 11 and 21 facing each other come close to each other while being inserted into the body mold 30. The molding material G supplied between the two is press-molded.

[0030] In the illustrated example, the upper mold 10 is held by the upper mold holding member (second mold holding member) 15 together with the trunk mold 30, and the lower mold 20 is formed by the lower mold holding member (first mold holding member). Die holding member) 25. These holding members 15 and 25 are all made of a magnetic material such as a tungsten alloy, and heating means such as a high-frequency induction heating coil (for example, a mold heating device 134 as shown in FIG. 8 described later) The heat is transmitted to the upper and lower molds 10, 20 and the trunk mold 30.

The heating means includes an upper mold heating means for heating the upper mold 10 and the upper mold holding member 15 and a lower mold heating means for heating the lower mold 20 and the lower mold holding member 25, and heating both. It is preferable that the temperature can be adjusted individually.

In addition, a fixed shaft 40 is attached to the upper mold holding member 15 on the upper surface side thereof. At the same time, on the lower surface side of the lower mold holding member 25, a drive shaft 50 connected to drive means having an elevating mechanism such as an air cylinder (not shown) is attached. As a result, the lower mold 20 moves up and down along the axial direction with respect to the upper mold 10 so that the upper and lower molds 10 and 20 are close to and away from each other. The drive shaft may be attached to the upper mold holding member 15 and the lower mold holding member 25 may be attached to the fixed shaft. A drive shaft may be separately attached to the upper mold holding member 15 and the lower mold holding member 25 so that both the upper and lower molds 10 and 20 move up and down along the axial direction.

The upper mold holding member 15 that holds the upper mold 10 together with the trunk mold 30 includes an upper mold support 16 and an upper mother mold 17. The upper mother die 17 is a cylindrical shape that concentrically surrounds the trunk die 30 and is fixed to the lower surface of the upper die support 16. On the upper side of the body mold 30 is formed a projecting portion 31 that projects in the radial direction as shown in the figure, and when the upper mother die 17 is fixed to the lower surface of the upper mold support base 16, this projecting portion 31 is It is sandwiched between a step surface 17 a formed on the inner periphery of the upper mold 17 and the lower surface of the upper mold support 16. The body mold 30 is held and fixed to the upper mold holding member 15 in a state where the projecting portion 31 is sandwiched, and movement in the horizontal direction and the axial direction is suppressed.

The upper mold 10 has a shape in which a small-diameter portion 12 on which a molding surface 11 is formed and a large-diameter portion 13 having a diameter larger than that of the molding surface 11 are arranged concentrically. The upper die holding member 15 is held in a state of being inserted in a shape. In the open state shown in FIG. 1, the lower surface of the large-diameter portion 13 of the upper mold 10 inserted into the body mold 30 is an annular step surface 30a formed on the upper inner peripheral side of the body mold 30. A gap S is formed between the upper surface of the upper mold 10 and the lower surface of the upper mold support 16.

Therefore, the upper mold 10 can be slid in the barrel mold 30 in the axial direction by the gap S, but the upper mold 10 is placed in the trunk mold 30 during the press molding operation. Since the inserted state is maintained, the horizontal clearance C2 at the sliding portion between the upper mold 10 and the trunk mold 30 is extremely small (for example, 5 am or less on one side, preferably 2 μm or less on one side). Can be kept.

When the lower mold 20 is raised and the mold is closed, the molding material G on the molding surface 21 of the lower mold 20 abuts on the molding surface 11 of the upper mold 10 and pushes up the upper mold 10. As a result, the upper mold 10 slides within the body mold 30 by the amount of the gap S and contacts the lower surface of the upper mold support 16, and as shown in FIG. A gap is formed between the step surface 30 a of the trunk mold 30. The thickness of the molded body is once defined here, but after this, when cooled, the upper mold 10 slightly lowers due to its own weight following the thermal contraction of the molded body, and the upper and lower molds 10, 20 and the molded body. Cooling can be performed while maintaining close contact with.

Similarly to the upper mold 10, the lower mold 20 has a shape in which a small diameter portion 22 formed with a molding surface 21 and a large diameter portion 23 larger in diameter than the molding surface 21 are arranged coaxially. It is held by a lower mold holding member (first mold holding member) 25 having a mold support base 26 and a lower base mold 27 fixed to the upper surface of the lower mold support base 26.

The lower mold 27 has a lower diameter inner peripheral surface 27a on the upper side of the inner peripheral surface, and the lower mold 20 is a lower mold holding member. When held at 25, an annular insertion groove 28 that opens upward is formed between the lower die 20 and the small diameter portion 22. When the press forming operation is performed, the lower side of the barrel die 30 is inserted into the insertion groove 28, and the small diameter portion 22 of the lower die 20 is also inserted into the barrel die 30 (see FIG. 3). ).

[0036] When the small-diameter portion 22 of the lower mold 20 is inserted into the barrel mold 30, the inner peripheral surface of the barrel mold 30 comes into contact with the upper and lower molds 10, 20, respectively. Therefore, it is possible to secure 20 coaxiality. At this time, if the clearance C3 between the outer peripheral surface of the small-diameter portion 22 of the lower mold 20 and the inner peripheral surface of the lower side of the body mold 30 is too large, the axis centers of the upper mold 10 and the lower mold 20 will shift and tilt tilt shift will occur. As a result, it becomes difficult to ensure the coaxiality of the upper and lower molds 10 and 20. For this reason, the clearance C3 between the outer peripheral surface of the small-diameter portion 22 of the lower mold 20 and the inner peripheral surface of the lower side of the body mold 30 is 0.5-10 111 in consideration of the required eccentric accuracy of the optical element. It is preferably 1 to 5 μm.

[0037] On the other hand, the lower side of the inner peripheral surface of the lower master die 27 is a large-diameter inner peripheral surface 27b, and an annular shape formed at a step portion between the large-diameter inner peripheral surface 27b and the small-diameter inner peripheral surface 27a. The large-diameter portion 23 of the lower mold 20 is held loosely between the lower mother mold 27 and the lower mold support base 26 so as to be sandwiched between the step surface 27c and the upper surface of the lower mold support base 26. It has become so. Thus, a predetermined clearance C1 is provided between the outer peripheral surface of the large-diameter portion 23 of the lower mold 20 and the large-diameter inner peripheral surface 27b of the lower master mold 27 while restricting the axial movement range of the lower mold 20. By ensuring this, the lower mold 20 can move in the horizontal direction (direction perpendicular to the axial direction) by the clearance C1.

[0038] In the example shown in the drawing, when the large-diameter portion 23 of the lower mold 20 is held loosely between the lower mother mold 27 and the lower mold support base 26, A plurality of rolling members 60 are spread between the die support base 26 (lower die holding member 25) so as to be able to roll as the lower die 20 moves horizontally. As a result, the lower mold 20 can move smoothly in the horizontal direction.

[0039] Here, the rolling member 60 is preferably a spherical member having a uniform diameter. As the rolling member 60, silicon nitride (Si N), silicon carbide (SiC), zircoure (ZrO), alumina (Al 2 O 3)

3 4 2 2 3

), Cermets containing tungsten carbide (WC), etc., and other metals with high hardness and high heat resistance. A shaped member can be used. The rolling member 60 made of these materials can be used alone or in combination.

The shape of the rolling member 60 may be a spherical shape, a cylindrical shape, a flat spherical shape, or the like. 1S Ease of processing of the rolling member 60, easy to obtain height (diameter) accuracy, easy to roll. From this point, a spherical shape is most preferable.

[0040] When the molding material G such as optical glass is press-molded using the molding die according to this embodiment, the molding material G corresponds to a temperature at which the viscosity becomes 10 ⁶ to 10 ¹² dPa's. Press molding is repeated periodically while being heated to a temperature (approximately 400 to 900 ° C), and a load of several kg / cm ² to several hundred kg / cm ² is applied to the mold and molding material G. .

At this time, the load is also applied to the plurality of rolling members 60 disposed between the lower die 20 and the lower die support base 26 (lower die holding member 25) at a high temperature. For this reason, the rolling member 60 is required to have a predetermined strength at the press molding temperature (about 400 to 900 ° C.). In general, compressive strength correlates with bending strength, so if the rolling member 60 is formed using ceramics with a bending strength of 300 MPa or more at the press molding temperature, it will deform even under a press load at high temperatures. There will be no wear or deterioration. Conversely, when ceramics or metals with a bending strength at the press molding temperature of less than 3 OOMPa are used as the rolling member 60, the rolling member 60 may be deformed and cannot be used for smooth rolling operation. .

Silicon nitride (Si N), silicon carbide (SiC), zircoure (ZrO), alumina (Al 2 O 3)

Ceramics such as 3 4 2 2 3 have a bending strength of 400 MPa or more at room temperature and are temperature dependent, but have a bending strength of 300 MPa at the press molding temperature. In addition, since the Vickers hardness is 1000 HV or more, deformation or wear does not deteriorate even when a load is applied when the molding material G such as optical glass is press-molded.

[0041] The number n of rolling members 60 spread between the lower die 20 and the lower die support 26 is determined by the area a of the cross section passing through the center of the rolling member 60 and the rolling members on the lower die support 26. Is determined according to the area (in the example shown, the area of the bottom surface of the recessed portion 26a, which will be described later) A, between which 0.3 ≤ a X n / A ≤ It is preferable that the relationship of 0.8, preferably 0.5≤a X n / A≤0.7 is satisfied.

[0042] The number n of rolling members 60 does not satisfy the above relationship! /, And the arrangement of the rolling members 60 is biased In some cases, the lower mold 20 cannot be held horizontally, and the heat transfer from the lower mold holding member 25 to the lower mold 20 becomes insufficient, and the lower mold 20 is efficiently heated. It tends to be impossible. On the other hand, if the number n of rolling members 60 exceeds the above relationship, each rolling member 60 will not be able to roll freely, and hinder smooth horizontal movement of the lower mold 20. There is.

[0043] Considering the assemblability of the mold, as shown in the figure, a recessed portion 26a is formed on the upper surface of the lower mold support 26, and the rolling member 60 is accommodated in the recessed portion 26a. Is preferable. By doing so, it is possible to prevent the rolling member 60 from falling off when assembling the mold.

In order to accommodate the rolling member 60 and prevent its falling off, the recessed portion 26a includes a lower mold 20 and a lower mold holding member 25 (the lower mold support base 26) facing each other via the rolling member 60. ) And at least one surface. Therefore, instead of forming the recess 26a on the upper surface of the lower mold support 26, a similar recess may be formed on the lower surface of the lower mold 20, and the rolling member may be accommodated in the recess.

As described above, in the present embodiment, the lower mold 20 is held by the lower mold holding member 25 so as to be movable in the horizontal direction, and the lower mold 20 and the lower mold holding member 25 are A plurality of rolling members 60 are laid in between so that the lower mold 20 can move smoothly in the horizontal direction so that the coaxiality of the upper and lower molds 10 and 20 is highly secured. Yes.

That is, the body mold 30 is held and fixed to the upper mold holding member 15 in a state in which the movement in the horizontal direction and the axial direction is suppressed, so that the press molding operation starts as shown in FIG. When the lower mold 20 is raised and inserted into the trunk mold 30 from the lower opening of the trunk mold 30, the axial center force of the lower mold 20 does not match the axial centers of the upper mold 10 and the trunk mold 30. However, the lower mold 20 moves smoothly in the horizontal direction indicated by the arrow in FIG. 2 while being inserted into the trunk mold 30, and this exerts an unreasonable force on the lower mold 20 and the trunk mold 30. The lower die 20 is guided to a position that is coaxial with the upper die 10 and the barrel die 30, and the upper and lower die 10, 20 can be highly secured.

[0046] In this way, when the coaxiality of the upper and lower molds 10 and 20 is secured to a high degree, the guide part 32 whose diameter is tapered downward is formed on the inner peripheral surface of the lower part of the trunk mold 30. Forming It is preferable to leave. When the press molding operation is performed, if the peripheral portion of the small-diameter portion 22 of the lower die 20 comes into contact with the guide portion 32, insertion of the lower die 20 into the body die 30 is prevented. The lower mold 20 is smoothly inserted into the body mold 30 while being guided by the guide portion 32, and the lower mold 20 is moved horizontally. The inclination angle Θ of the guide portion 32 with respect to the axial direction is preferably 45 ° or less, more preferably 30 ° or less, and even more preferably 10 ° or less.

[0047] Further, the lower mold 20 is movable in the horizontal direction within the range of the alignment C1 between the outer peripheral surface of the large-diameter portion 23 and the large-diameter inner peripheral surface 27b of the lower master mold 27. Maximum value of clearance C1 Force Upper limit of horizontal movement of lower mold 20 For this reason, it is preferable that the guide portion formed on the body portion 30 has a larger diameter W force than the clearance C1.

As a result, even when the horizontal axis of the lower mold 20 is maximized, the peripheral portion of the small-diameter portion 22 of the lower mold 20 can be brought into contact with the guide portion during the press molding operation. The force S prevents the insertion of the lower mold 20 into the body mold 30 and the horizontal movement of the lower mold 20.

Here, the horizontal movement amount of the lower mold 20 is the clearance between the outer peripheral surface of the large-diameter portion 23 of the lower mold 20 and the large-diameter inner peripheral surface 27b of the lower master mold 27 as described above. Force defined by C1 If this clearance C1 is too small, the clearance may be lost due to the difference in thermal expansion between the lower mold 20 and the lower mother mold 27, and the movement of the lower mold 20 may be hindered. In addition, when multiple press forming is performed, if the clearance C1 is too small, the allowable range of position accuracy of each die will be reduced, and there is a risk that force, curling, and inability to close the die will occur. .

On the other hand, if the clearance C1 is too large, the allowable movement range of the lower mold 20 becomes excessive, so that when the mold is closed, the body mold 30 comes into contact with the molding surface 21 of the lower mold 20 to form the molding surface 21. May be damaged or it may become impossible to close the mold.

Considering these facts, the clearance C1 is preferably 10 to 200 mm 111.

[0049] In the mold according to the present embodiment as described above, there are no restrictions on the materials used for the upper mold 10, the lower mold 20, the trunk mold 30, and the like. Cermets such as titanium oxide, aluminum oxide, zirconium oxide, titanium carbide, etc. A hard material whose surface is coated with diamond, refractory metal, noble metal alloy, carbide, nitride, boride, oxide or the like can be used. In addition, the parts that come into contact with the molding material G, such as the molding surfaces 11 and 21 of the upper and lower molds 10 and 20 and the inner peripheral surface of the barrel mold 30, may be coated to prevent fusion with the molding surface. it can. Such a coating can be a noble metal film, a carbon film, a hydrogenated carbon film, or the like, and can be a film similar to a known release film. For example, a film containing carbon or a hydrocarbon as a main component can be formed with a predetermined film thickness using a known means such as a vapor deposition method, a sputtering method, an ion plating method, or plasma CVD. .

[0050] [Mold press mold / second embodiment]

Next, a second embodiment of the mold according to the present invention will be described.

FIG. 4 is a cross-sectional view schematically showing the molding die according to the present embodiment, and FIG. 4 (a) shows a state where the molding material G is supplied to the molding die opened. Figure 4 (b) shows the closed state.

[0051] The present embodiment is different from the first embodiment described above in that an elastic member 35 that urges the body mold 30 toward the lower mold 20 is provided. As such an elastic member 35, a coil panel or the like can be used. For example, as shown in the figure, a step portion 36 as a receiving seat is formed on the inner peripheral surface of the trunk mold 30, and the step portion 36, By attaching an elastic member 35 between the cross-section 10a formed in the step portion between the small-diameter portion 12 and the large-diameter portion 13 of the upper die 10, the barrel die 30 force S is urged toward the lower die 20. It ’s a good idea to do it.

[0052] The press molding operation is started, and the lower mold 20 is lifted and inserted into the body mold 30 so that the molding material G is press-molded between the upper and lower molds 10 and 20. This press molding In the process, the opening end surface of the lower mold 20 on the lower mold 20 side comes into contact with the upper surface of the large diameter section 23 of the lower mold 20. At this time, the trunk mold 30 is urged toward the lower mold 20 by the elastic member 35 and is pressed against the lower mold 20 that is rising.

Therefore, the position of the lower mold 20 and the trunk mold 30 is set in a horizontal plane by placing the end face of the lower mold 20 on the lower mold 20 side and the upper surface of the large-diameter portion 23 of the lower mold 20 in a horizontal plane. Is correctly defined, and it is possible to obtain a molded body with better eccentric accuracy.

This embodiment differs from the first embodiment in the above points, but has the same configuration except for the above. Because of that! /, Therefore, detailed description of other configurations! / Is omitted.

[Mold Press Mold / Third Embodiment]

Next, a third embodiment of the mold according to the present invention will be described.

FIG. 5 is a cross-sectional view schematically showing the mold according to this embodiment, and FIG. 5 (a) shows a state where the molding material G is supplied to the mold that has been opened. Fig. 5 (b) shows a closed state.

In the present embodiment, in contrast to the second embodiment described above, an annular groove 16a capable of accommodating the upper side edge of the trunk mold 30 is formed on the lower surface of the upper mold support base 16, When the upper and lower molds 10 and 20 are in the closed state, the upper edge of the body mold 30 protrudes upward from the upper surface of the upper mold 10 and fits in the groove 16a formed on the lower surface of the upper mold support base 16. It is like that.

With this configuration, a long sliding distance between the upper mold 10 and the lower mold 20 and the trunk mold 30 can be secured, and the inclination of the upper mold 10 and the lower mold 20 with respect to the trunk mold 30 is minimized. Therefore, it is possible to press-mold an optical element with higher eccentricity accuracy.

[0056] The present embodiment is different from the second embodiment in the above points, but otherwise has the same configuration! /, So the detailed description of other configurations! / Is omitted. To do.

[0057] [Mold Press Mold / Fourth Embodiment]

Next, a fourth embodiment of the mold according to the present invention will be described.

FIG. 6 is a cross-sectional view schematically showing the molding die according to the present embodiment, and FIG. 6 (a) shows a state where the molding material G is supplied to the molding die opened. Fig. 6 (b) shows the closed state.

In the present embodiment, the lower mold 20 has a convex surface on the molding surface 21, and a support member 70 that supports the molding material G is disposed around the molding surface 21. The support member 70 supports the molding material G supplied onto the molding surface 21 with its upper end projecting upward from the molding surface 21 of the lower mold 20.

At this time, a step portion 21a is formed around the molding surface 21 of the lower mold 20, and an elastic member 70a is mounted between the step portion 21a and the support member 70, and the support member 70 is biased upward. It has become like this. In order to avoid the interference of the support member 40 during press molding, the support member 40 is pushed down by the retracting mechanism 71 according to the proximity movement of the upper and lower molds 10, 20. (See FIG. 6 (b)), it is configured to retract from the periphery of the molding surface 21 of the lower mold 20.

[0059] By doing so, even when a meniscus lens having a concave surface or a biconcave lens is molded, a molding material can be reliably and stably formed on the molding surface 21 of the lower mold 20 having a convex surface. G can be supplied. In addition, the support member 70 is retracted from the periphery of the molding surface 21 of the lower mold 20 as the upper and lower molds 10, 20 move close together, so that the support member 70 does not substantially interfere with the shape of the molded body. Therefore, it is possible to manufacture a high-precision optical element having a better eccentric accuracy.

[0060] Although the present embodiment is different from the other embodiments in the above points, the other configurations have the same configuration! /, So the detailed description of other configurations! / Is omitted. To do.

[0061] [Mold Press Mold / Fifth Embodiment]

Next, a fifth embodiment of the mold according to the present invention will be described.

FIG. 7 is a cross-sectional view schematically showing the mold according to the present embodiment, and FIG. 7 (a) shows a state where the molding material G is supplied to the mold that has been opened. Fig. 7 (b) shows the closed state.

[0062] In the present embodiment, an interposed member having a curved surface of contact with the lower mold holding member 25 between the lower mold holding member 25 (lower mold support base 26) and the rolling member 60. 80 is interposed. The interposition member 80 is made of the same material as the lower mold 20. In the illustrated example, a recess 80a is formed on the upper surface of the interposed member 80, and the rolling member 60 is accommodated in the recess 80a so that the mold can be assembled. The curved surface of the intervening member 80 is preferably a spherical surface. The force S is preferable, and the radius of curvature varies depending on the radius of the optical element to be molded.

[0063] By doing this, even if the lower mold 20 is inclined with respect to the trunk mold 30, the interposed member 80 corrects the inclination of the lower mold 20 while swinging along the curved surface. To do. Therefore, the lower mold 20 is inserted into the body mold 30 while maintaining a high degree of coaxiality by correcting the inclination by the interposition member 80 and horizontally moving, and is a molded body with good eccentricity (tilt and shift). Can be press-molded.

[0064] Although this embodiment is different from the other embodiments in the above points, the other configurations have the same configuration! /, So the detailed description of other configurations! / Is omitted. To do. [0065] [Press molding equipment]

Next, an example of a press molding apparatus suitable for press molding with the above mold will be described.

FIG. 8 is a schematic plan sectional view of the press molding apparatus. As shown in this figure, the press molding apparatus 100 includes a heating chamber 120 and a molding chamber 130, and a passage 140 communicating between them.

[0067] The internal space of the heating chamber 120, the forming chamber 130, and the passage 140 is a sealed space that is blocked from the outside. The outer wall of the sealed space is formed by stainless steel or other members, and the sealing material is used. Its airtightness is guaranteed. The internal spaces of the heating chamber 120, the molding chamber 130, and the passage 140 are in a non-oxidizing gas atmosphere such as nitrogen gas when optical glass is molded.

[0068] The heating chamber 120 is an area for preheating the supplied forming material G prior to pressing. The heating chamber 120 includes a glass heating device 122, a molding material supply handler (hereinafter referred to as a supply node and a drum 123), and a carry-in section 121 for supplying the molding material G into the heating chamber 120 from the outside. is set up. The carry-in unit 121 is provided with a carry-in chamber (not shown) in order to carry the molding material G while maintaining hermeticity. After filling with, open the door on the heating chamber 120 side and sequentially carry the molding material G into the interior.

[0069] The supply gate 123 is configured to convey the molding material G carried in from the carry-in section 121 to a heating region by the glass heating device 122 and convey the heated molding material G to the molding chamber 130. The supply node 123 has a levitating dish 125 at the tip of its arm 124, and holds the molding material G while floating by the gas. In this example, the arm 124 including the levitating dish 125 is horizontally supported by the drive unit 123a fixed in the heating chamber 120, and the arm 124 is rotated in the horizontal direction with a rotation angle of about 90 °. . Further, the arm 124 is configured to be capable of withdrawing and withdrawing in the radial direction with the drive unit 123a as the center, whereby the held molding material G can be conveyed to the molding chamber 130.

[0070] The glass heating device 122 is for heating the supplied molding material G to a temperature corresponding to a predetermined viscosity. To raise the temperature of molding material G to a certain level stably In addition, it is preferable to use a heating device using resistance heating or high-frequency heating. As shown in the figure, the glass heating device 122 is installed under the movement path of the molding material G held on the arm 124, and can heat the molding material G while the molding material G is being conveyed by the arm 124. . The arm 124 may be stopped on the glass heating device 122 for a predetermined time to heat the molding material G. These matters are determined according to the time required for heating the target molding material G.

[0071] On the other hand, the molding chamber 130 is an area for pressing the molding material G preheated in the heating chamber 120 to form a molded body G1 having a desired shape. In addition, a handler for carrying out the molded body G1 (hereinafter referred to as a carry-out handler 132) and a carry-out section 131 for carrying out the press-formed molded body G1 to the outside are installed. The carry-out unit 131 includes a carry-out chamber (not shown) filled with a non-oxidizing gas in order to carry the molded body G1 to the outside while maintaining the airtightness of the molding chamber 130. The compact G1 delivered from the carry-out handler 132 is once carried into the carry-out chamber and then carried out to the outside.

[0072] The pressing device 133 receives the molding material G conveyed from the heating chamber 120 by the supply nozzle 123, and presses the molding material G to form a molded body G1 having a desired shape. The press device 133 includes the forming die M as described above, and presses the forming material G supplied between the upper and lower dies 10 and 20 by the forming surfaces 11 and 21. A mold heating device 134 for heating the mold M is installed around the mold M. A preferred embodiment of the mold heating device 134 is a heating method using high frequency induction. Prior to pressing the forming material G, the forming die M is heated by the die heating device 134 and maintained at a predetermined temperature. The temperature of the mold M at the time of pressing may be substantially the same as or lower than the temperature of the preheated molding material G.

The carry-out handler 132 delivers the molded body G1 pressed by the press device 133 to the carry-out unit 131. The carry-out handler 132 includes a suction pad 132c at the tip of an arm 132b that is rotatably supported by the drive unit 132a. The suction pad 132c vacuum-sucks the optical glass on the lower mold of the mold M and enables the carry-out handler 132 to carry it. The compact G1 adsorbed by the rotation of the arm 132b is transported under the carry-out part 131 and placed on a lifting means (not shown) installed here. After retreating arm 132b, The lifting means is raised, and the molded body G1 is delivered to the carry-out unit 131.

The molding chamber 130 is provided with an opening / closing door 135 on the front side thereof, and the opening / closing door 135 is for an operator to access the inside of the molding chamber when the press molding apparatus 100 is maintained and inspected. A seal member 35a is provided around the open / close door 135, and airtightness in the molding chamber 130 is ensured with the open / close door 135 closed during pressing. The open / close door 135 includes a glass-made window 135b (for example, quartz glass), from which the press molding can be visually recognized from the outside.

[0075] The passage 140 that connects the heating chamber 120 and the molding chamber 130 enables the supply handler 123 to transfer the molding material G from the heating chamber 120 to the molding chamber 130, and allows gas between the two chambers to pass therethrough. Allows exchange. Thereby, at the time of press molding, the pressure, gas concentration, and temperature of the heating chamber 120 and the molding chamber 130 are made substantially constant. An airtight valve 141 is disposed in the passage 140. When the airtight valve 141 is closed, the heating chamber 120 and the molding chamber 130 are shut off in an airtight state. The airtight valve 141 is fully opened at the time of press molding. The airtight valve 141 is closed at the time of maintenance or inspection in the molding chamber 130 by an operator, and the airtight state on the heating chamber 120 side is maintained.

[0076] [Method for producing molded article]

Next, an embodiment to which the method for producing a molded body according to the present invention is applied will be described. The method for producing a molded body according to the present invention is to press-mold using the above-described molding die, and is preferably carried out by the press molding apparatus.

In the above press molding apparatus, the molding material G is sequentially supplied from the carry-in part 121 into the apparatus, and the molded body G1 is continuously press-molded. Here, focusing on the molding of one molding G1. The procedure will be described.

[0077] (a) Loading process

Prior to molding, the gas inside the heating chamber 120 and the molding chamber 130 is gas-exchanged to a non-oxidizing gas. For example, a non-oxidizing gas is always supplied indoors and kept at a positive pressure. In this non-oxidizing gas atmosphere, the glass heating device 122 and the mold heating device 134 are energized and maintained at a predetermined temperature. In this state, the airtight valve 141 of the passage 140 is opened. In the first step, the molding material G is supplied to the heating chamber 120. Specifically, the molding material G is first placed in the carry-in chamber of the carry-in section 121, and after this is exhausted and replaced with gas, it is supplied to the heating chamber 120. When the molding material G is supplied, the arm 124 of the supply nozzle 123 is positioned below the carry-in section 121, and the molding material G from the carry-in chamber is placed on the floating plate 125 of the supply nozzle 123.

[0078] (b) Molding material heating step

Upon receiving the molding material G, for example, a spherical glass preform, the supply nozzle 123 immediately rotates its arm and moves its flotation plate 125 onto the glass heating device 122. Here, the non-oxidizing gas is jetted from below into the floating dish 125, and thus the molding material G is heated and softened while floating on the floating dish 125. The molding material G is heated to a temperature corresponding to a viscosity of 1S 10 ⁶ to 10 ⁹ dPa's.

[0079] (c) Mold heating process

In addition, when the heated molding material G is supplied to the mold M, the mold M has a temperature corresponding to the viscosity of 10 ⁸ to 10 ¹² dPa's of the glass. The mold M is preheated by induction heating by the heating device 1 34.

Here, the temperature setting of the heated upper and lower molds 10 and 20 may be the same as that of the upper and lower molds 10 and 20 as described above, or a temperature difference may be provided. For example, the lower mold 20 can be made hotter than the upper mold 10 or the lower mold 20 can be made colder than the upper mold 10 depending on the shape of the molded body. When adding a temperature difference, the temperature difference between the upper and lower molds 10, 20 should be in the range of 2 to 15 ° C.

[0080] (d) Molding material supply process

After that, the supply nozzle 123 is driven to supply the molding material G to the molding surface 21 of the lower mold 20 of the press device 133 in the molding chamber 130. That is, the arm 124 is further rotated from the heating position, stopped when the floating plate 125 reaches a position facing the passage 140, and then the arm 124 is extended so that the floating plate 125 is in the mold open state in the press device 133. Extend to M and drop the molding material G on the float 125 onto the lower mold 20. Thereafter, the supply drum 123 is moved to the initial position, that is, below the carry-in portion 121 by retracting the arm, and waits to receive the next molding material G. When the softened molding material G is transported and supplied to the lower mold 20, if the molding material G comes into contact with the members of the transport mechanism, the surface is likely to be defective. Defects on the surface will adversely affect the surface shape of the molded product G1. Therefore, it is advantageous to prevent such an adverse effect by using the supply blade 123 of this example that conveys the softened molding material G in a state of being floated by gas and drops it to the lower mold.

[0081] (e) Pressing process

As soon as the molding material G is supplied to the lower mold 20 and the arm is retracted from the molding mold M, the mold closing (pressing operation) starts. As shown in FIGS. 2 and 3, the lower mold 20 is raised, and the molding material G is pressed between the upper mold 10 and a desired molded body G1. The stroke of the lower mold 20 for pressing is a preset value based on the thickness of the molded body G1 to be molded. In the cooling process of the next process, the molded body G1 after molding is heated. The force S can be set to a predetermined amount in anticipation of contraction. In general, the press molding speed is desirably 3 to 600 mm / min. When molding a glass lens with a diameter of 15 mm or more, it is desirable to set it at 3-80 mm / min. The pressing procedure can be arbitrarily set according to the shape and size of the optical glass to be molded. For example, a procedure for performing multiple pressurizations such as performing secondary pressurization after releasing the load after initial pressurization can be employed.

[0082] Here, in the mold M of this example, the lower mold 20 is held by the lower mold holding member 25 in a state of being movable in the horizontal direction, and the lower mold 20 and the lower mold holding member 25 are A plurality of rolling members 60 are laid in between. Therefore, when the mold is closed, even if there is a shaft misalignment between the upper mold 10 and the lower mold 20, the lower mold 20 moves smoothly in the horizontal direction when the lower mold 20 is inserted into the body mold 30. Then, the upper and lower molds 10 and 20 are aligned, and pressing is performed in this state.

In addition, since the lower mold 20 can be smoothly moved in the horizontal direction by the rolling of the rolling member 60, the guide portion 32 of the body mold 30 is in a single-contact state with the outer periphery of the lower mold 20 when the mold is closed. However, the lower mold 20 without excessive stress acting on the trunk mold 30 and the lower mold 20 moves in the horizontal direction, and is quickly inserted into the trunk mold 30, so that the upper and lower molds are in a coaxial state.

Therefore, position correction is performed so that the lower mold 20 without causing rubbing or galling in the body mold 30 and the lower mold 20 is coaxial with the upper mold 10, and press molding can be performed with high accuracy. [0083] (f) Cooling and mold release process

Simultaneously with the start of pressing on the molding material or after pressing starts, the mold heating device 134 is cut off, and further, a non-oxidizing gas flows into the molding die and is blown from the outside. As a result, the mold M is cooled. Then, when the temperature of the mold 150 becomes equal to or lower than the glass transition point, the lower mold 20 is lowered and released so that the molded body G1 can be carried out. In order to prevent cracking of the molded body and occurrence of radiation flaws, the cooling rate can be set to 50 to 200 ° C / min as an average value from the start of cooling to mold release. The cooling rate at the start of cooling is preferably smaller than the average cooling rate, and it is desirable to increase the cooling rate as the mold release temperature is approached from the viewpoint of preventing cracking. The mold release temperature should be less than or equal to the glass transition point Tg. Force that can be applied S Generally, it is desirable to set the value within the range from (Tg – 50 ° C) to Tg.

[0084] (g) Extraction process

Next, the compact G1 on the lower mold 20 is transported to the unloading part 131 by the unloading handler 132. That is, as shown by an imaginary line in FIG. 4, the carry-out handler 132 is driven, the arm 132b is rotated, and the suction pad 132c at the tip is moved onto the lower mold. The molded body G1 on the lower mold is sucked by the suction pad 132c, the arm 132b is rotated, and the arm 132b is conveyed to the lifting means below the unloading section 131. Pass the shape G1.

[0085] (h) Unloading process

Next, the elevating means is raised and the molded body G1 is carried out of the molding chamber 130 through the carry-out chamber of the carry-out section 131. The mold heating device 134 is energized as soon as the molded body G1 is unloaded from the lower mold, and heats the mold to a predetermined temperature in preparation for the next press molding.

By repeatedly performing the above steps (a) to (h), the compact G1 can be produced efficiently.

Note that the shape of the optical glass to be press-molded can be molded into a biconvex lens, a convex meniscus lens, a concave meniscus lens, a biconcave lens, and the like, which are not particularly limited. The size of the molded body is not particularly limited, but generally, a molded body having a diameter of about 2 mm to 35 mm can be molded. If it is 2mm or less, the glass material is easy to cool, so it breaks. This is because if it is 35 mm or more, molding takes time and it becomes extremely difficult to obtain a good surface. Furthermore, the shape of the optical glass can be spherical, aspherical, or a combination thereof.

Example

Next, the present invention will be described in more detail with reference to specific examples.

[0087] The mold press mold shown in Fig. 1 is mounted on the press molding apparatus shown in Fig. 8, and preformed with normoborosilicate glass (transition point 514 ° C, yield point 545 ° C) as molding material G Was used to mold a biconvex lens having an outer diameter of 15 mm.

[0088] First, a glass material hot-formed into a biconvex curved shape is preheated to 490 ° C, and is held on the molding surface of the lower die held by the lower base mold preheated to about 470 ° C in the molding chamber. The glass material was supplied. Immediately, the lower die and the lower die were raised by raising the drive shaft, and the lower die was assembled in the body die held by the upper mother die preheated to about 470 ° C.

At this time, the lower mold is guided by the trunk mold guide, and the shaft center of the lower mold is formed by a plurality of rolling members made of Si N disposed between the lower mold and the lower mold support. Upper shaft

3 4

The lower mold moved horizontally so as to coincide with the heart, and the lower mold was inserted into the trunk mold.

[0089] In this example, the clearance Cl between the outer peripheral surface of the lower mold large diameter portion and the inner peripheral surface of the lower mold holding member, that is, the horizontal movable distance of the lower mold is set to 0.1 mm at the maximum, The clearance between the upper end surface of the lower mold large diameter part and the lower mold holding member, that is, the vertical movable distance of the lower mold is 0.1 mm at the maximum, and the inner peripheral surface of the body mold and the outer peripheral surface of the lower mold small diameter part Clearance C2 to 5 in and B ^.

In addition, several carbon-containing films were formed on the surface of the glass material introduced, and hard carbon films were formed on the upper and lower mold surfaces by sputtering.

[0090] The upper and lower master dies were heated to 596 ° C corresponding to a glass viscosity of 10 ⁸ dPa's by high-frequency induction heating, maintained for a predetermined time and soaked, and then the lower master dies as shown in Fig. 3 Was raised and pressed at a pressure of 100 kg / cm ".

Next, the upper and lower molds and the molded lens were cooled at a cooling rate of 50 ° C./min until the glass transition point was reached. At this time, the upper mold followed the shrinkage of the glass, and it was cooled in a state where only the upper mold weight was applied. That is, the contact between the upper surface of the lens and the upper mold was maintained during cooling. See you!

[0091] When the mold temperature reached 490 ° C, the mold was rapidly cooled with a cooling gas, and after the mold temperature reached 370 ° C or lower, the lower mold was lowered and released. The lower mold was lowered to the bottom of the molding chamber, and the press-molded lens was taken out using the suction pad. The removed lens may be annealed or centered as necessary.

[0092] The above pressing process was repeated 2000 times, and the obtained lenses were inspected. As a result, each lens was highly accurate in terms of shift and tilt decentering accuracy and met the reference value, and the surface quality was also good. .

In addition, the sliding part between the body mold and the lower mold was observed, but no traces of rubbing or galling that caused problems were found.

[0093] While the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. Needless to say!

[0094] For example, in the above-described embodiment, a force showing an example of a mold having a pair of upper and lower molds 10, 20 may be provided with two pairs of upper and lower molds 10, 20, as shown in FIG. Further, although not particularly shown, three or more pairs of upper and lower molds 10 and 20 may be provided. In this way, a plurality of molded bodies can be simultaneously molded by a single press molding operation. The example shown in FIG. 9 corresponds to a configuration in which two molding dies similar to those in the first embodiment described above are arranged side by side and these are attached to a common fixed shaft 40 and drive shaft 50.

In the above-described embodiment, the lower mold 20 is the first mold, and the force showing an example in which the rolling member 60 is spread between the lower mold 20 and the lower mold holding member 25 is shown in FIG. As shown, the upper mold 10 is the first mold, and the rolling member 60 is spread between the upper mold 10 and the upper mold holding member 15.

Here, the example shown in FIG. 10 substantially corresponds to a case in which the top and bottom of the mold according to the first embodiment described above are reversed. More specifically, the overhanging portion 31 formed on the lower side of the body mold 30 is sandwiched between the cross section 30a formed on the inner periphery of the lower mother mold 27 and the lower mold support base 26, so that the body The mold 30 is held and fixed to the lower mold holding member 25 together with the lower mold 20. On the other hand, the upper mold 10 has a large-diameter portion 13 held loosely between the upper mold support 16 and the upper mother mold 17 as shown in the figure. ing. A concave portion 17a is formed on the step surface of the upper master die 17 facing the lower surface of the large-diameter portion 13 of the upper die 10, and the rolling members 60 are spread on the concave portion 17a.

Accordingly, the insertion groove 18 formed between the small-diameter portion 12 of the upper mold 10 and the upper mother mold 17 even if the axes of the upper and lower molds 10, 20 and the trunk mold 30 do not coincide with each other. In addition, when the upper side of the body mold 30 is inserted, the peripheral part of the small-diameter portion 12 of the upper mold 10 abuts on the guide part 32 formed on the inner periphery of the upper side of the body mold 30, so that the upper mold 10 However, it is guided to a position coaxial with the lower mold 20 and the trunk mold 30, so that the upper and lower molds 10, 20 can be secured.

Industrial applicability

The present invention is applied to a mold press mold for press molding a molding material such as a glass preform and a method for producing a molded body using such a mold press mold.

Claims

The scope of the claims

[1] first and second molds having an arbitrarily shaped molding surface;

The first and second mold forces, which are opposed to each other so that their molding surfaces face each other, and are coaxially inserted; and

A first mold holding member for holding the first mold so as to be movable in a horizontal direction; and a first mold holding member disposed between the first mold and the first mold holding member. A plurality of rolling members that roll with movement in the direction;

A mold press mold characterized by comprising:

[2] A guide portion having a tapered diameter is formed on the inner peripheral surface of the opening portion of the barrel mold on the side where the first mold is inserted, and the guide mold is configured such that the first mold is the barrel mold. 2. The mold according to claim 1, wherein when the first mold is inserted, the first mold is brought into contact with the first mold and guided so as to be coaxial with the second mold. Press mold.

[3] The mold press mold according to any one of claims 1 and 2, wherein the rolling member is a spherical member having a uniform diameter.

[4] The mold press mold according to any one of [1] to [3], wherein the rolling member comprises a ceramic force having a bending strength at a press molding temperature of 300 MPa or more.

[5] The force according to any one of claims 1 to 4, wherein the rolling member is made of one or more materials selected from silicon nitride, silicon carbide, zirconium oxide, and alumina. The mold press mold of description.

[6] A concave portion for accommodating the rolling member is formed on at least one surface of the first die and the first die holding member facing each other with the rolling member interposed therebetween. The mold press mold according to any one of claims 1 to 5, wherein:

[7] An elastic member that urges the body mold toward the first mold,

When press-molding a molding material with the first and second molds,

The opening end surface of the barrel mold on the side where the first mold is inserted is pressed against a part of the first mold by the urging force of the elastic member. The force of any one of 1 to 6, the mold press mold according to 1.

[8] The first mold has a convex surface on the molding surface;

A support member for supporting a molding material supplied on the molding surface of the first mold, located around the molding surface of the first mold;

A retracting mechanism for retracting the support member from the periphery of the molding surface of the lower mold according to the proximity movement of the first and second molds;

The mold press mold according to any one of claims 1 to 7, characterized by comprising:

[9] The present invention is characterized in that an interposed member having a curved surface that comes into contact with the first mold holding member is interposed between the first mold holding member and the rolling member. The mold press mold according to any one of the above.

[10] The first and second molds having a molding surface having an arbitrary shape and the first and second molds are arranged so as to face each other so that the molding surfaces face each other, and are inserted coaxially. A body mold in which a guide portion is formed on the inner peripheral surface of the opening on the side where the first mold is inserted; a first mold holding member that holds the first mold so as to be movable in the horizontal direction; A mold press mold comprising a plurality of rolling members disposed between one mold and the first mold holding member;

Drive means for raising and lowering at least one of the first and second molds;

Heating means for heating the mold press mold;

Using a molding apparatus equipped with

In manufacturing a molded body by pressing a molding material with the mold press mold heated to a predetermined temperature by the heating means, and transferring the shape of the molding surface to the molding material,

By moving up and down at least one of the first and second molds by the driving means, the first mold is inserted into the barrel mold, and at this time, the first mold is The rolling member rolls in contact with the guide portion formed on the mold and moves in the horizontal direction, and guides the first mold so as to be coaxial with the second mold. A method for producing a molded product characterized by the above.

[11] Prior to press molding, the molding material is preheated and the mold press forming is performed. 11. The method for producing a molded body according to claim 10, wherein the mold is preheated, and the preheated molding material is supplied to the preheated mold press mold to perform press molding.