Abstract: A method of manufacturing a light-emitting device including a light-emitting element mounted on a substrate and sealed with a glass. The method includes heating the glass by a first mold that is heated to a temperature higher than a yield point of the glass, the glass contacting the first mold, and pressing the glass against the light-emitting element mounted on the substrate supported by a second mold to seal the light-emitting element with the glass.

Abstract: Disclosed is a mold used as a bottom mold for manufacturing glass molded bodies by accepting molten glass droplets that are dripped in and by compression molding of the molten glass droplets in conjunction with a top mold. The mold is provided with a base material that has a mold surface for compression molding of molten glass drops, and a coating layer formed on the mold surface. The surface of the coating layer formed on the mold surface has a rough surface region that comprises the center of the mold surface, and a mirror finished region that surrounds the outside of the rough surface region and has a lower arithmetic mean roughness Ra than the rough surface region.

Abstract: In order to produce a fluorophosphate glass including P5+ at a small content on the composition thereof, the composition is adjusted so as to provide well-balanced chemical durability and thermal stability. In the production of a fluorophosphate glass in which O2?/P5+>3.7, Al3+ content is in a predetermined amount or more and p5+ content is in a predetermined amount or less, a glass raw material is prepared by using an AlF3 in which the content of Al2O3 is limited to the range from 1 to 5% by mass, and the raw material is melted to produce the fluorophosphate glass.

Abstract: A parison mold assembly for a press-and-blow glassware forming machine includes a neck ring for molding a finish portion of a parison, a parison mold for molding a body portion of the parison, and a plunger for insertion through the neck ring into the parison mold for pressing a hot glass gob against inner surfaces of the neck ring and the parison mold. The plunger has an outer surface of revolution around a central axis, including a first portion disposed within the neck ring when the plunger is fully inserted through the neck ring into the parison mold, a second portion spaced from the first portion, and a transition third portion extending between the first and second portions.

Abstract: Mold for manufacturing glass containers such as salad has at least one through hole through their walls with three distinct parts; a die defining the outer shape of the container adapted to receive a gob of glass in a plastic state; a plunger, the inner shape of the container to be molded; and a closing ring. The three parts are pressed onto one another to cause pressing and expansion of the glass gob in the cavity of the mold. The die has a monolithic construction of one piece, and the closing ring and the one-piece die have at least one protruding portion defining the shape of the through hole to be molded and formed in the container.

Abstract: A mold set includes: a first mold and a second mold placed so that they sandwich an optical material and face each other; and a first spacer and a second spacer provided between the first and second molds, wherein: the first spacer secures an interval between the first and second molds at a first temperature achieved in a process of pressurizing the optical material; the first spacer shrinks in a mold opening-closing direction more greatly than the second spacer while the first temperature is changing to a second temperature achieved in a process of cooling the optical material; and the second spacer secures the interval between the first and second molds at the second temperature.

Abstract: A manufacturing apparatus of the present invention has a pair of dies that form each cylindrical surface, and a plane member that forms side surfaces of an element. The upper die and the lower die has a cylindrical surface which is worked so as to have generatrix which connects intersection points between a non-arc axis and a cylindrical section and between an arc center axis and the cylindrical section. The plane member is pressed against reference surfaces of the upper die and the lower die. In this state, a glass material is put between the upper die and the lower die, and a distance between the upper die and the lower die is decreased. As a result, the cylindrical surfaces of the upper die and the lower die and the plane of the plane member are transferred onto the glass material.

Abstract: A neck ring for molding a glass container neck finish that includes at least one closure attachment feature. The neck ring includes two semi-annular bi-metal neck ring halves, each consisting essentially of a neck ring insert of wear-resistant metal construction, and a neck ring body of heat-conductive metal construction different from said wear-resistant metal construction and formed around said neck ring insert so as to embed it in said neck ring body. Each of said neck ring halves has a glass-contacting cavity face that includes a first surface portion formed by said inserts for molding the at least one closure attachment feature on the neck finish, and a second surface portion formed by said bodies for molding portions of the neck finish excluding the at least one closure attachment feature.

Abstract: Provided is an optical element manufacturing method by which optical elements, such as a beam shaping element having a molded side surface, are highly efficiently and accurately manufactured by pressure-molding a molten glass drop. After supplying a lower molding die with the molten glass drop of a prescribed volume at a temperature higher than that of the molding die, the molten glass drop is pressure-molded by the molding die, and a free surface solidified without being in contact with the molding die is formed between a molded upper surface and the molded side surface. The volume of the molten glass drop to be supplied is 0.8 times or more but not more than 0.97 times the volume of a space configured by an extended molded upper surface, an extended molded side surface and the molded lower surface when the molded upper surface and the molded side surface are extended.

Abstract: In one aspect, there is provided a process for manufacturing a lower mold for receiving a falling molten glass droplet, in which without narrowing the option for material for a lower mold, any occurrence of air retention can be favorably prevented and a lower mold excelling in durability can be obtained. The process comprises the film forming step of forming a coating layer on a base material and the surface roughening step of roughening the surface of the coating layer. Preferably, the coating layer contains at least one element selected from among chromium, aluminum and titanium.

Abstract: A device for manufacturing a hollow glass item is provided. The device includes a mold having a cavity with a shape substantially corresponding to the outer shape of the glass item and a punch movable between a passive position outside the cavity and an active position inside the cavity, the punch including a hollow body having at least one raised or hollow pattern on at least one outer surface. A method and a punch are also provided.

Abstract: There is provided a device for manufacturing a molded glass body, including a fall-prevention means for preventing the glass molded body which has stuck on the upper mold from falling down on the lower mold. Thus, the molded glass body does not damage the lower mold, even if the molded glass body which has stuck on the upper mold falls down from the upper mold, during a period from an end of the pressure molding to releasing and withdrawing the molded glass body obtained by the pressure molding from the any one of the upper mold and the lower mold.

Abstract: This invention provides a molding die in which increase of the surface roughness due to crystal growth of chromium oxide is restrained, and thereby allowing long term use without deteriorating surface roughness of a glass gob or a molded glass article. The invention also provides a method for manufacturing the molding die, a glass gob, and a molded glass article. A molding die is provided with a substrate having a molding surface and protective film containing chromium formed thereon, and the protective film has the X-ray diffraction peak intensity of (110) plane of chromium higher than the X-ray diffraction peak intensity of (200) plane.

Abstract: In a molding apparatus in which upper and lower dies are held in a bearing, there are provided pipes for introducing N2 gas used for controlling temperatures of balls of the bearing, whereby difference in temperature between the guide member and the upper and lower dies is controlled. With this structure, it is possible to prevent generation of an excessive compressive force between the upper die and the lower die and the bearing, to thereby prevent breakage of the dies. Further, it is also possible to prevent formation of gaps between the upper die and the lower die and the bearing, to thereby mold an optical element excellent in accuracy of an optical axis.

Abstract: A mold for use in production of a glass optical element includes an upper mold and a lower mold on which a molten glass is dropped, the lower mold being provided with a molding surface for press molding the molten glass with the upper mold. A recess for forming a positioning protrusion on the glass optical element is provided at an outer side of the molding surface. An inclined section is provided at an inner circumferential surface of the recess closer to the molding surface. The inclined section is inclined such that, when the molten glass dropped on the molding surface spreads toward the outer side, the molten glass enters the recess while maintaining contact with the inclined section.

Abstract: In a process for a thin-plate form glass molded body, an upper mold part having a pressing surface is used together with a lower mold part having a setting surface arranged to be opposed to the pressing surface. A melted glass lump is pressed between the pressing surface and setting surface. The pressing is performed to set the temperature (° C.) of the thin-plate form glass molded body to a temperature of Tg?20 or higher, and lower than Tg, wherein Tg represents the glass transition point (° C.) of the glass, in a period of 0.8 second or less after the end of the pressing.

Abstract: A glass forming apparatus and a glass forming method of high economical merit and high production efficiency are provided. More specifically, the glass forming apparatus has dies, in which at least one die is divided into a heat exchange unit and a press unit, and in the glass forming apparatus and glass forming method, the plane precision is improved in the contact dividing surfaces of the heat exchange unit and the press unit. A glass forming apparatus includes a die having a press surface for pressing a glass material, in which the die has a plurality of dies, and at least one die is divided into a heat exchange unit and a press unit. Preferably, the surface precision of at least one part of each dividing surface in contact with the heat exchange unit and the press unit has a flatness (PV) of 500 ?m or less, and the plane precision of at least one part of the dividing surface has a surface roughness (Ra) of 100 ?m or less.

Abstract: A molding apparatus of a glass material according to the present invention is characterized by containing means for holding a glass material and a molding die in contact with each other, means for heating the glass material and the molding die, and means for applying a voltage across the glass material and the molding die, in which press-molding is performed by electrostatic attraction acting between a surface of the glass material and a surface of the molding die. Further, a molded product of a glass material according to the present invention is characterized by including an alkali metal as a component, in which a concentration of the alkali metal is lowered in vicinity of a surface to be molded as compared with that of a glass base material.

Abstract: Provided is an apparatus for manufacturing a glass molding which can manufacture a glass molding having a high precision optical surface. An apparatus for manufacturing a glass molding has a lower die which receives molten glass, and an upper die which conducts pressure molding of the molten glass supplied to the lower die in conjunction therewith, wherein the upper die has a first molding surface which transfers the optical surface, a second flat molding surface provided around the periphery of the first molding surface, and a third molding surface provided around the periphery of the second molding surface and tilting relative to the central axis of the upper die passing through the center of the first molding surface to spread in the direction of the lower die.

Abstract: The invention relates to an installation and a method for producing glass stoppers which are provided with a head portion and are used for sealing wine bottles and sparkling wine bottles. The installation comprises a mold for producing glass stoppers, a feeder system for supplying the mold with molten glass, a multistation press, and a removing and handling system for the finished glass stoppers.

Abstract: There is provided a device for manufacturing a molded glass body, including a fall-prevention means for preventing the glass molded body which has stuck on the upper mold from falling down on the lower mold. Thus, the molded glass body does not damage the lower mold, even if the molded glass body which has stuck on the upper mold falls down from the upper mold, during a period from an end of the pressure molding to releasing and withdrawing the molded glass body obtained by the pressure molding from the any one of the upper mold and the lower mold.

Abstract: In the initial stage of die-opening operation when an upper core 3 moves upward together with an upper die plate 1, an upper cavity die 2 is biased downwardly by an elastic member 10 so as to press the lower surface of the upper cavity die 2 against the upper surface of a lower cavity die 6 and keep their contact, thereby forcing a molded glass element 4 to remain on a lower core 5 by utilizing the difference in outside diameter between the lower core 5 and the upper core 3. This makes it possible to securely release the molded glass element 4 from the upper core 3 and leave the molded product on the lower core 5 upon die opening, enabling smooth removal and automated transportation of the molded product.

Abstract: A mold for molding a lens includes a first mold part and a second mold part. The first mold part includes a substantially frustoconical guiding chamber defined therein, and a first molding surface in the substantially frustoconical guiding chamber. The second mold part includes a main body having a substantially frustoconical protrusion with a substantially cylindrical recess defined therein. The substantially frustoconical protrusion has a second molding surface in the substantially cylindrical recess. The substantially frustoconical protrusion is configured for inserting into and matingly engaged in the substantially frustoconical guiding chamber of the first mold part, thus aligning the first molding surface with the second molding surface.

Abstract: A first sleeve 30 regulates the horizontal relative position between an upper mold 10 and a lower mold 20 that are insertable into the first sleeve 30 from its both end sides. A second sleeve 40 provided inside the first sleeve 30 and surrounding the outer periphery of a molding surface 21 of the lower mold 20 supports at least part of an outer peripheral portion of a molding material 50 placed on the molding surface 21 of the lower mold 20, thereby preventing position offset and slip-off of the molding material 50. In this state, the molding material 50 is press-molded between the upper mold 10 and the lower mold 20.

Abstract: A molding device includes an upper mold 10 (first mold), a lower mold 20 (second mold) and a body mold 30 that aligns axes of the upper and lower molds 10, 20 with each other by being fitted to an exterior of the upper mold 10 and an exterior of the lower mold 20 with the body mold 30 straddling the upper and lower molds 10, 20. The lower mold 20 is supported by a support member 50. The support member 50 can support the lower mold 20 with the lower member 20 being in a floating state.

Abstract: A mold apparatus includes a first mold die, a second mold die and an interjacent mold die. The first mold die has a first molding surface. The second mold die has a second molding surface. The interjacent mold die is arranged between the first and second mold dies, and has a third molding surface and an opposite fourth molding surface. The third molding surface and the first molding surface cooperatively form a first molding chamber. The fourth molding surface and the second molding surface cooperatively forms a second molding chamber.

Abstract: A mold for molding a product in a cavity formed by closing the mold is provided. The mold includes a first half; a second half; and a plurality of aligning members which contact respective outer circumferential surfaces of a first die of the first half and a second die of the second half, at least in three directions, when the mold is closed. At least one of the aligning members is moved toward the outer circumferential surfaces of the first die and the second die, and then each of the aligning members sandwiches the first die and the second die, which enables a center axis alignment between the first die and the second die.

Abstract: There are provided a die for forming a glass substrate which does not generate cracks when the glass substrate is released from the die, in a method of manufacturing a glass substrate by forming molten glass with a pressing operation, a method of manufacturing a glass substrate using the die, a method of manufacturing a glass substrate for an information recording medium using a glass substrate manufactured by the method, a method of manufacturing an information recording medium, a glass substrate for an information recording medium, and an information recording medium. In the die for forming a glass substrate used for pressing molten glass to manufacture a glass substrate for an information recording medium, a lower die includes a die surface on which a plurality of grooves or depressions are almost uniformly formed.

Abstract: A plastic molding die provided with a cavity where a plastic material is put in, wherein a part of an inner surface of the cavity is configured with an elastic body. A molding portion corresponding to a molding surface of a molded product is disposed on the inner surface of the cavity, and the elastic body is arranged on a portion other than the molding portion of the inner surface of the cavity. The plastic molding die may be a molding die for compression molding. The elastic body is made of rubber, and has an upper temperature limit higher than a glass-transition temperature of the plastic material. The degree of rubber hardness of the elastic body is from 50 to 100.

Abstract: A molding die with a simple structure, which produces an optical element of a low eccentricity degree, without narrowing the option for materials of the molding die and a method for producing an optical element by using the molding die are provided. The molding die includes a top die, bottom die, guiding member having a guiding surface kept in contact with the side faces of the top die and bottom die during the press molding of glass material, an expansion member for pressing the top die and bottom die against the guiding surface by thermal expansion by heating, and a supporting member for supporting the guiding member and expansion member. Among these members, the expansion member has the greatest thermal expansion coefficient. The press molding is applied to the glass material while the top die and bottom die are pressed against the guiding member by the thermal expansion of the expansion member.

Abstract: A method of molding an optical component which includes providing a first mold and a second mold which mold the optical component, a cylindrical body whose rotational symmetry axis is identical with a second symmetry axis about which a second mold is rotationally symmetric, a trunk mold whose rotational symmetry axis is identical with a first symmetry axis about which a first mold is rotationally symmetric, a supporting means which supports the first mold in such a way that the first mold moves relatively to the trunk mold in parallel with the first symmetry axis, and a second tapered surface and a first tapered surface which contacts the second tapered surface, which connect the cylindrical body with the trunk mold in such a way that the second symmetry axis is identical with the first symmetry axis.

Abstract: Disclosed is a mold for glass substrate molding, which enables to produce a glass substrate having high flatness by a method for producing a glass substrate through press molding of molten glass. Also disclosed is a method for producing a glass substrate by using such a mold. Specifically disclosed is a mold comprising a lower mold having a first molding surface for pressing a molten glass supplied thereto, and an upper mold having a second molding surface for pressing the molten glass against the first molding surface. In the first molding surface, the surface roughness Ra of the peripheral portion which is in contact with the molten glass after pressing is higher than the surface roughness Ra of the central portion which is in contact with the molten glass before pressing.

Abstract: A mold for molding a product in a cavity formed by closing the mold includes a first half; a second half; and a plurality of aligning members which come in contact with each side circumferential surface of the first half 100 and the second half at least in three directions, when the mold is closed. After the mold is closed, at least one of the aligning members is moved to contact the aligning member with the each side circumferential surface of the first half and the second half, which enables a center axis alignment between the first half and the second half.

Abstract: A mold apparatus includes a first mold die, a second mold die and an interjacent mold die. The first mold die has a first molding surface. The second mold die has a second molding surface. The interjacent mold die is arranged between the first and second mold dies, and has a third molding surface and an opposite fourth molding surface. The third molding surface and the first molding surface cooperatively form a first molding chamber. The fourth molding surface and the second molding surface cooperatively forms a second molding chamber.

Abstract: A preform production apparatus for precision press molding, which is downsized but can produce preforms at a lower cost, and a production method thereof using the apparatus are provided. The production method of a preform for precision press molding includes forming a molten glass body C by way of receiving and cutting molten glass A, being flowed continuously from a discharge nozzle 2, by a support member 1 or by way of allowing molten glass to fall in drops from a discharge nozzle 2 and receiving thereof by a support member 1, and transferring the molten glass body C from the support member 1 to a mold 5 by way of displacing the support member to near the mold 5, disposed not to be beneath the discharge nozzle 2, while increasing the viscosity of the molten glass body C on the support member 1.

Abstract: A process for glass molding includes the steps of: gradually increasing a working temperature to a formation temperature T1 while maintaining a normal pressure and an initial mold position; maintaining the formation temperature T1 for about 60 seconds, and during this period; increasing the normal pressure to a first pressure P3, the first pressure P3 being in the range of 200-400 newtons; increasing the first pressure P3 to a second pressure P2, the second pressure P2 being in the range of 500-700 newtons; increasing the second pressure P2 to a formation pressure P1, the formation pressure being in the range of 700-900 newtons; decreasing the formation pressure P1 to a cooling pressure P4; gradually decreasing the formation temperature T1 to a slow-cooling temperature T3 while maintaining the cooling pressure P4 and gradually de-compacting the mold position.

Abstract: A press die and a molding process can form a disk member having a shaft shaped portion at a center with satisfactory circularity and flatness in a disk portion, dimensional precision in the shaft shaped portion, and concentricity between the disk portion and the shaft shaped portion at the center. The press die is designed for press molding of a glass substrate of a disk member with a shaft shaped portion at a center thereof. The press die includes an upper die forming an upper surface of the disk member, an intermediate die having a shaft forming hole portion for forming a shaft shaped portion projecting from a disk portion of the disk member, a lower die for forming a lower surface of the shaft shaped portion and a guide member for guiding the upper die, the intermediate die and the lower die.

Abstract: The present invention relates to a manufacturing method for an optical glass element, in which molten glass 9 is pressed between a lower mold 1 and an upper mold 8, and the pressing process is carried out while maintaining a space 10 between a border area (5, 6) of a molding face 2 belonging to the lower mold 1 and a circumferential face 3 located on the periphery thereof and glass 9, and an optical glass element manufactured by such a method.

Abstract: The present invention provides a flat fluorescent lamp. The flat fluorescent lamp comprises a single plate. Consequently, the flat fluorescent lamp is structurally safe, brightness of the flat fluorescent lamp is high, and efficiency of the flat fluorescent lamp is also high without the provision of other additional optical components. The present invention also provides a method of manufacturing such a flat fluorescent lamp.

Abstract: A molding die for an optical element, comprises a die base body formed by shaping an amorphous alloy having a super-cooled liquid phase, and a die face formed by applying a die face forming process onto a part of the die base body and used to form an optical surface of the optical element or a dimensional reference surface.

Abstract: A preform manufacture apparatus is provided which can produce a preform at low cost. A preform manufacture apparatus 1 has a first mold 20 which receives molten glass, and a second mold 50 which receives a molten glass block moved from the first mold 20. The first mold 20 has a receiving surface 20A which receives molten glass, and is dividable into two or more of split dies 30 and 40 at the receiving surface 20A.

Abstract: A molding apparatus for molding a press-molded product by heating and softening a material and press-molding the material into a predetermined shape by the use of a mold, includes a pair of dies which form the mold, each of which comprises a molding surface facing with the other, and one of which is fixed to a structure member of the molding apparatus, driving means for moving the other die towards and away from the one die, heating means for heating the dies, detecting means for detecting the displacement of a part displaced by thermal deformation of the structure member, and a control section for calculating a correction value for a moving distance of the other die with reference to the result of detection by the detecting means and delivering an instruction to the driving means so as to move the other die in accordance with the moving distance corrected by the correction value.

Abstract: A mold is disclosed which has a vertical front face having a glass object surface defined therein and a stepped vertical rear surface. The upper portion of the rear surface projects outwardly from the lower portion of the rear surface. The lower rear surface includes the top surface of two vertically spaced pairs of “T”s.

Abstract: A pressing plunger mechanism for a glassware forming machine has at least one pressing plunger which in normal operation can be moved axially in a reciprocating manner together with a pressing plunger receiver between an inoperative position and a pressing position. A piston rod of a piston is fastened to each pressing plunger receiver, which piston can be displaced in a cylinder of a pressing plunger holder. The pressing plunger holder can be moved axially in a reciprocating manner by a first drive and is connected in a non-rotatable manner to a threaded spindle. A nut which can be rotationally driven by the first drive is engaged with the threaded spindle and is coupled to a driven shaft of an angular gear. An input shaft of the angular gear can be rotationally driven by an electric servo motor of the first drive.

Abstract: A press-molding mold includes a first mold (10), a second mold (20), a complementary element (30) arranged between the first mold (10) and the second mold (20), a washer (40) arranged between the second mold (10) and the complementary element (30), and a bushing (50) for receiving the first mold (10), the second mold (20), the complementary element (30) and the washer (40) therein. The first mold (10) includes a first molding surface (132) and a second molding surface (134) surrounding the first molding surface (132). The second mold (20) includes a third molding surface (232) spatially corresponding to the first molding surface (132). The complementary element (30) includes a fourth molding surface (321) spatially corresponding to the second molding surface (134). The washer (40) has a thickness custom-tailored for maintaining a desired distance between the fourth molding surface and the second molding surface.

Abstract: A press-molding mold includes a first mold part (10), a second mold part (20), a bushing (40), a first latching pin (50) and a second latching pin (70). The second mold part (20) defines a longitudinal central axis (21) and includes a first positioning portion (211) having an annular groove (212) defined in an outer surface thereof and a plurality of first longitudinal holes (213) defined therein. The bushing (40) includes a second positioning portion (430) defining a second longitudinal through hole (432) configured for alignment with one of the first longitudinal holes (213) and a transverse through hole (434) spatially corresponding to the annular groove (212). The first latching pin (50) latchingly extends through the transverse through hole (434) and insertion into the annular groove (212). The second latching pin (70) latchingly extends through the second longitudinal hole (432) and insertion in one of the first longitudinal hole (213).

Abstract: An optical lens molding apparatus includes a cylindrical mold, a first mold core, a second mold core and a correctional ring. The first and the second mold core have a columnar shape and are disposed inside the cylindrical mold to form a cavity. Furthermore, the first and the second mold core have a planar portion at the end surface facing the cavity. The correctional ring is disposed on the planar portion of the second mold core. The correction ring corrects any face tilting of the molded optical lens due to the tilting of the first mold core. The present invention also provides a precision molding apparatus for forming precision parts.

Abstract: A molding die for an optical element with a lens-barrel in which the lens-barrel is set in the molding die includes a tubular guide die, a upper die and a lower die sliding in the guide die Also an optical raw material is placed in the lens-barrel and the optical element is sandwiched, heated and pressurized between the upper die having a transfer surface and the lower die having a transfer surface, thereby integrally forming the optical element in the lens-barrel. Outside diameter portions designed to be equal to the inner diameter of the guide die are provided for the upper die and lower die, wherein the outside diameter portion is fitted in the guide die so as to be able to slide only in the axial direction.

Abstract: A press die and a molding process can form a disk member having a shaft shaped portion at a center with satisfactory circularity and flatness in a disk portion, dimensional precision in the shaft shaped portion, and concentricity between the disk portion and the shaft shaped portion at the center. The press die is designed for press molding of a glass substrate of a disk member with a shaft shaped portion at a center thereof. The press die includes an upper die forming an upper surface of the disk member, an intermediate die having a shaft forming hole portion for forming a shaft shaped portion projecting from a disk portion of the disk member, a lower die for forming a lower surface of the shaft shaped portion and a guide member for guiding the upper die, the intermediate die and the lower die.

Abstract: A press molding apparatus includes upper and lower mother molds 102 and 104. Each of the mother molds 102 and 104 has four molding surfaces arranged in a single line and satisfies the relationship given by L×?×?T/t<0.0008, where L represents the length, t, the thickness, ?, the thermal expansion coefficient, and ?T, the temperature difference between both ends in the thickness direction during induction heating. The press molding apparatus may include a pressing mold set including upper mother molds 102a and 102b attached to a common fixed shaft 118 through upper supporting shafts 110a and 110b and lower mother molds 104a and 104b driven by a common drive shaft 120 through lower supporting shafts 112a and 112b. The upper mother molds 102a and 102b and the lower mother molds 104a and 104b are collectively heated by induction heating coils 122 and 124, respectively.