JP2009242139A - Forming method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To take out a formed article in a hot environment while preventing die oxidation. <P>SOLUTION: A heating unit 13 is disposed so as to freely move between a heating position for heating around a pair of dies 11, 12 and a non-heating position left upward. The heating unit 13 shields the pair of dies 11, 12 and a space around these when it is in the heating position. A partition member 14 is attached to the lower side of the heating unit 13. The partition member 14 shields the pair of dies 11, 12 and a space around these when the heating unit 13 is in the non-heating position. When a formed article is taken out, piping for exhaust is switched over and an inert gas is fed into the space shielded by the partition member 14, and while keeping the space under high pressure, the formed article is taken out from a mouth 14a disposed in the partition member 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a molding method in which a molding material is disposed between a pair of molds, the pair of molds and the molding material are heated to press the molding material, and then the pair of molds and the molded product are gradually cooled to take out the molded product. And the apparatus.

  In recent years, optical lenses made of glass or the like have been molded by a press molding method due to higher precision of molding technology. In this case, a gob or lens preform (hereinafter referred to as “molding material”) is placed between a pair of molds having a high-precision molding surface, and heating means such as high-frequency induction heating or heating using an infrared lamp. Thus, the mold and the molding material are heated to a temperature in the vicinity of the glass transition point, and thereafter, one mold is pressed toward the other mold to mold the molding material.

  When heating the mold and the molding material, it is necessary to prevent oxidation of the metal part of the mold and a member adjacent to the mold. Therefore, the mold and the vicinity of the top end of the vertical axis that supports the mold are accommodated in a molding chamber in which the atmosphere can be adjusted, and an inert gas is allowed to flow into the molding chamber, thereby allowing the mold and the surrounding metal to flow. The space including the member is maintained in an inert gas atmosphere or a vacuum atmosphere (Patent Document 1).

  In general, as shown in FIG. 10, an operation for manufacturing a glass optical element using press molding includes a process of supplying a molding material, heating, pressing, slow cooling, rapid cooling, and taking out a molded product. It is divided into. At the time of press molding, the mold is heated to a temperature equal to or higher than the glass transition point (press temperature of general glass: about 500 to 600 ° C.). Thereafter, the molded product is taken out after being cooled to a temperature below the glass transition point (500 to 300 ° C.) by a slow cooling step and then cooled to room temperature (0 to 70 ° C.) by a rapid cooling step.

By the way, the slow cooling and rapid cooling steps take time to cool to room temperature. In addition, since it is necessary to heat the mold and the molding material to a temperature higher than the glass transition point at the next molding, the heating process also takes time. Therefore, it is desired that the rapid cooling is omitted and only the slow cooling is performed, and then the molded product is taken out to shorten the cycle time related to the molding.
JP 2001-253722 A

  However, the mold temperature after the slow cooling process is still higher than the glass transition point. When the molded product is taken out in such a high temperature environment, the molding chamber is opened, and external air enters and oxygen in the air reacts with the high temperature metal. There is a fault that it oxidizes. Further, if an inert gas is supplied into the space through the inside of the pair of molds, the pair of molds may be excessively cooled.

  The present invention has been made in view of the above points, and provides a molding method and apparatus capable of taking out a molded product in a high-temperature environment while preventing oxidation of the mold and reducing the cycle time. The purpose is to do.

  In the present invention, a pair of molds, a heating unit that heats the molding material placed between the pair of molds, pressurizing means that presses the heated molding material and molds a molded product, and the pair of molds A partition member for partitioning the mold and the surrounding space; a gas supply means for supplying an inert gas into the space through the pair of molds; an inert gas having an opening exposed in the space and passing through the opening And a supply / exhaust switching mechanism for switching between the supply of gas and the exhaust in the space.

  At the time of slow cooling, the gas supply means supplies the inert gas into the space through the inside of the pair of molds, and the supply / exhaust switching mechanism is exposed to a portion other than the pair of molds, that is, the space. The space is exhausted through the opening. At least when the molded product is taken out, the supply / exhaust switching mechanism supplies the inert gas into the space partitioned by the partition member through the opening.

  The heating unit is disposed at a heating position surrounding the pair of molds at least during heating and pressing (molding). When taking out the molded product, it is necessary to retract the disturbing heating unit to the non-heating position. If the heating unit is used to shield the pair of molds and the space around them when heating and pressing, air flows into the space when the heating unit is retracted. Therefore, a fixed shielding cylinder (partition member) may be provided on both shafts arranged on both sides of the pair of molds and supporting each mold, and a heating unit may be provided around the shielding cylinder. In this case, an entrance for taking out the molded product is provided in the shielding cylinder. When the heating unit moves to the heating position, the entrance / exit is shielded, and by retracting to the non-heating position, the entrance / exit is exposed, so that the molded product can be taken out with the atmosphere of the space maintained in an inert gas atmosphere.

  Further, as the partition member, the shielding cylinder may be moved in conjunction with the movement of the heating unit. In this case, the shielding unit is pulled out by moving the heating unit to the non-heating position to shield the space. Furthermore, the partition member may be a telescopic member such as a bellows or a bellows that is displaced between a shielded state that shields the space in conjunction with the movement of the heating unit and a retracted state that retracts from the space. When using an expansion / contraction member, one end is attached to the end of the heating unit opposite to the direction moving toward the non-heating position, and the heating unit is fixed in the direction moving toward the heating position. Attach the other end to the frame. As the entrance / exit, a rectangle or a circle having a size for allowing the robot arm and the transfer arm to enter and exit is suitable. This doorway is generated when the stretched state is reached.

  The heating unit includes a holding member that holds heating means for heating the pair of molds and the molding material. The holding member shields the space including the pair of molds and the periphery thereof when the heating unit moves to the heating position during heating and molding (pressing).

  As the heating means, a cylindrical heat ray permeable inner wall arranged on the inside so as to face a pair of molds, and a plurality of infrared rays arranged outside the heat ray permeable inner wall and arranged in the pressurizing direction And a lamp. An induction heating coil may be used instead of the infrared lamp. Also, the heat ray permeable inner wall needs to be formed of a material that absorbs less heat rays, such as a transparent quartz tube, so that the heat rays emitted from the infrared lamp can be efficiently irradiated onto the mold and the molding material. For this reason, it is preferable that a part of the holding member is constituted by a heat ray permeable inner wall.

  The gas supply means supplies an inert gas into the space through the inside of the pair of molds. The supply / exhaust switching mechanism supplies and exhausts the inert gas through a plurality of openings provided in the space and exposed to portions other than the pair of molds. It is preferable that any one of the plurality of openings is provided in the holding member of the heating unit so that the inert gas passes through the front surface of the transparent quartz tube, since the cooling action of the heating means can also be performed.

  According to the present invention, the partition member that partitions the pair of molds and the space around the pair, the gas supply means that supplies the inert gas into the space through the pair of molds, and the inert gas through the opening exposed in the space. Supply / exhaust switching mechanism that switches between supply of air and exhaust in the space, so that the supply / exhaust switching means supplies the inert gas through the opening to the space shielded by the partition member during the molded product removal process Therefore, since the pair of molds are not cooled excessively, the cycle time can be shortened. In addition, since the space can be made oxygen-free and the inside of the space can be at a higher pressure than the outside air, the outside air does not flow into the space even if the molded product is taken out through the inlet / outlet provided in the partition member. The molded product can be taken out while preventing oxidation underneath.

  Further, if gas is supplied into the space shielded by the partition member using the flow path of the gas supply means for supplying inert gas into the space through the inside of the pair of molds, the pair of molds may be excessively cooled. However, if an inert gas is supplied using a flow path exhausted from the opening exposed in the space, the pair of molds can be prevented from being excessively cooled, so that the heating process at the next molding is performed. The time concerning can be shortened.

  The lens molding apparatus 10 employing the present invention is roughly composed of an upper mold unit 11, a lower mold unit 12, a heating unit 13, a partition member 14 and the like as shown in FIGS. .

  The upper mold unit 11 is fixed to the fixed shaft 16 via a heat insulating member 15. The fixed shaft 16 is provided extending downward from an upper portion of a frame (not shown). The upper mold unit 11 includes a die plate 17, a fixed die 18, and an upper mold 19. The die plate 17 is made of ceramic or metal, the upper end is fixed to the heat insulating member 15, and the fixed die 18 is held at the lower end. The fixed die 18 is formed of ceramic or metal and constitutes a part of the die, and the upper die 19 is fixed to the die plate 17. The upper die 19 is made of ceramic or cemented carbide and has a molding surface on the lower surface.

  A drive mechanism 20 such as a screw jack is provided at the lower part of the frame (not shown). The drive mechanism 20 converts the rotation obtained from a drive source such as a servo motor into a linear motion and moves the drive shaft 21 up and down. A moving shaft 23 is attached to the tip of the drive shaft 21 via a load detector 22, and the lower mold unit 12 is provided to the tip of the moving shaft 23 via a heat insulating member 24. The output signal of the load detector 22 is taken into the control unit 25. The control unit 25 controls the drive mechanism 20 based on the output signal to control the speed, position, shaft load, and the like of the drive shaft 21.

  The lower mold unit 12 includes a die plate 27, a moving die 28, and a lower mold 29. The die plate 27 is formed of ceramic or metal, the lower end is fixed to the heat insulating member 24, and the moving die 28 is held at the upper end. The moving die 28 is made of ceramic or metal and constitutes a part of the die, and the lower die 29 is fixed to the die plate 27. The lower die 29 is made of ceramic or cemented carbide and has a molding surface on the upper surface.

  The heating unit 13 has a configuration in which the heating means is held by a holding member, and the heating position (see FIG. 2) in which the heating means surrounds the upper and lower mold units 11 and 12 and retreats in parallel with the press direction from now on. It is supported by a supporting means so as to be movable between the non-heating position (see FIG. 1). The support means is a guide rail 30 arranged parallel to the pressing direction. The heating unit 13 is moved to one of the two positions by driving obtained from the driving unit 31. The driving of the driving unit 31 is controlled by the control unit 25.

  The holding member is composed of upper and lower plates 33 and 34 and an outer cylinder 35 in a cylindrical shape. The heating means includes a plurality of infrared lamps 36 built inside the outer cylinder 35, and a transparent quartz tube (heat ray permeable inner wall) 37 constituting the inner cylinder. The transparent quartz tube 37 is a cylindrical quartz glass and constitutes a part of the holding member. The infrared lamps 36 are provided in a plurality of stages vertically on the outer periphery of the transparent quartz tube 37, and heat the pair of molds and the molding material through the transparent quartz tube 37 by radiant heat. The holding member shields the upper and lower mold units 11 and 12 and the space around them when in the heating position.

  Although not shown in the figure, the tip of a thermocouple for temperature measurement is attached inside the upper and lower mold units 11 and 12. The rear end of the thermocouple is connected to the control unit 25. The infrared lamp 36 is controlled to be turned on and off by the controller 25, and the output of the infrared lamp 36 is adjusted based on a detection signal obtained from the thermocouple. The infrared lamps 36 in each stage constitute a circular infrared lamp using a pair of semicircular (ohmic) infrared lamps. Although not shown, a reflection mirror is provided on the opposite side of the transparent quartz tube 37 with respect to the infrared lamp 36.

  The upper plate 33 of the heating unit 13 is provided with a plurality of gas supply / exhaust ports 40 which will be described in detail later. These gas supply / exhaust ports 40 are provided so that an inert gas is supplied into the space through the front surface of the transparent quartz tube 37. Thereby, since the cooling operation of the heating means can be performed, it is possible to prevent the fixed shaft 16 from being brought into contact with or close to the heat source and reaching a high temperature. A seal 48 is attached to the inner periphery of the upper plate 33. The seal 48 maintains an airtight state with the fixed shaft 16 while allowing the heating unit 13 to move. On the other hand, a lower support plate 41 constituting a part of the frame is provided on the outer periphery of the moving shaft 23. The lower support plate 41 is provided with a plurality of airtight holes 32 that allow movement of the moving shaft 23 while maintaining an airtight state, and a plurality of gas supply / exhaust ports 42 to be described in detail later.

  One end of a cylindrical partition member 14 is fixed to an end (lower end) opposite to the direction in which the heating unit 13 moves toward the non-heating position. The partition member 14 is a bellows that can be expanded and contracted with a heat-resistant material, and a lower end thereof is fixed to the lower support plate 41. This partition member 14 is displaced in an extended state in conjunction with the movement of the heating unit 13 to the non-heating position to shield the upper and lower mold units 11 and 12 and the space around them (see FIG. 1). In association with the movement of the heating unit 13 to the heating position, the heating unit 13 is displaced into a contracted state and retracts from the space (see FIG. 2).

  The partition member 14 is formed with an entrance / exit 14a that is generated in a rectangular shape when in the extended state. The entrance / exit 14a is an opening having a size that allows the robot arm 70 to enter and exit. The partition member 14 has a cylindrical shape when in the extended state. It may be a cylinder having a rectangular cross section or a polygon. In addition, it is preferable to make the partition member 14 transparent because the inside can be visually recognized. Furthermore, the entrance / exit 14a is not limited to a rectangle but may be a circle.

  As shown in FIG. 5, lens molding is roughly divided into five steps: supply of a molding material, heating (including waiting time), pressing, slow cooling, and removal of a molded product. Between the heating process, the pressing process, and the slow cooling process, the heating unit 13 is moved to the heating position, and is a space partitioned inside the heating unit 13 (the space including the upper and lower mold units 11 and 12 and the surrounding area). ). The heating unit 13 is moved to the non-heated position between the process of taking out the molded product and the process of supplying a new molding material. In association with this movement, the partition member 14 is displaced to the shielding state, The space is shielded by the member 14.

  At the start of slow cooling (time d1 shown in the figure), the upper and lower mold units 11, 12 and the molded product are gradually cooled. As shown in FIG. 4, this cooling is performed by the inert gas from the fixed shaft 16, the heat insulating member 15, and the plurality of openings 50 provided in the upper die unit 11 through the gas supply passage 49 provided in the upper die unit 11. While supplying (for example, nitrogen gas) to the space partitioned inside the heating unit 13, the lower mold unit 12 passes through the moving shaft 23, the heat insulating member 24, and the gas supply path 51 provided in the lower mold unit 12. An inert gas is supplied to the space from a plurality of openings 53 provided in the upper and lower mold units 11, 12 and the molded product. At this time, exhaust gas is exhausted through the gas supply / exhaust ports 40 and 42 to eliminate the retention of the inert gas and the increase in pressure in the space, thereby facilitating the control of the slow cooling. These gas supply / exhaust ports 40 and 42 constitute the opening of the present invention. The gas supply passages 49 and 51 are connected with a flow rate control meter (not shown). The control part 25 adjusts the supply amount of the gas supply apparatus connected to each gas supply path 49,51 based on the flow value obtained from a flow control meter. These gas supply devices, gas supply paths 49 and 51, and a plurality of openings 50 and 53 provided in the pair of molds constitute the gas supply means of the present invention.

  Supply / exhaust switching mechanisms 60 are connected to the pipes connected to the gas supply / exhaust ports 40 and 42, respectively. The supply / exhaust switching mechanism 60 includes a switching device 61, an exhaust valve 62, an exhaust device 63, and a gas supply device 64. The switch 61 is connected to a gas supply pipe to which a gas supply device 64 is connected and a discharge pipe to which an exhaust device 63 is connected via an exhaust valve 62. When the switch 61 is switched to the supply position, the gas supply pipe is connected to the gas supply / exhaust ports 40, 42, and the inert gas is supplied from the gas supply / exhaust ports 40, 42. Further, when switching to the exhaust position, the exhaust pipe is connected to the gas supply / exhaust ports 40, 42, and the gas supply / exhaust ports 40, 42 become the exhaust ports. The switching of each switching device 61 is individually controlled by the control unit 25. Although not shown, the gas supply pipe is connected to a flow rate control meter, and the control unit 25 individually adjusts the supply amount of the gas supply device 64 based on the flow rate value obtained from the flow rate control meter. To do.

  At the beginning of the molded product removal step (time e1 shown in FIG. 3), as shown in FIG. 5, the heating unit 13 is moved to the non-heating position. At this time, the inert gas is supplied from the gas supply / exhaust ports 40 and 42 to the space shielded by the partition member 14 by the switching of the switching devices 61. Thus, the atmosphere in the space is kept in an inert gas atmosphere from this point to the removal of the molded product and the supply of a new molding material to prevent mold oxidation. Further, the inside of the space is set to a pressure higher than that of the outside air by supplying an inert gas. For this reason, outside air does not flow into the space from the outside through the doorway 14a. In addition, you may make it perform the movement to the non-heating position of the heating unit 13 at the end of a slow cooling process.

  Although not shown, a temperature sensor and a pressure sensor for detecting temperature and pressure in the space are attached in the space. These detection signals are taken into the control unit 25. Based on the flow rate of each flow path, the temperature and pressure in the space, and the mold temperature, the control unit 25 includes at least a gas supply unit and a supply so that the flow rate, pressure, and temperature are preset for each process. -The exhaust gas switching mechanism 60 is individually controlled.

  The operation of the above configuration will be briefly described. As shown in FIG. 1, in the step of supplying the molding material, the heating unit 13 is moved to the non-heating position, and instead the partition member 14 is displaced to the extended state, so that the pair of molds and the surrounding space are separated from each other. 14 is shielding. At this time, each switching device 61 is switched to a supply position, and an inert gas is supplied to the space from each gas supply / exhaust port 40, 42. In such a state, the robot arm 70 enters and exits through the doorway 14a, and the molding material 71 is transferred to the lower mold unit 12.

  After the molding material 71 is supplied, as shown in FIG. 2, the heating unit 13 is moved to the heating position, and the partition member 14 is contracted in conjunction with this movement. At this time, the space is shielded by the heating unit 13 and the partition member 14 in the contracted state. After the heating unit 13 has moved to the heating position, the infrared lamp 36 is turned on to start heating. In the heating step, a small amount of inert gas is supplied to the space from the openings 50 and 53 through the gas supply passages 49 and 51 in order to prevent mold oxidation. At the start of heating, the control unit 25 switches each switch 61 to the exhaust position and exhausts the inert gas in the space from the upper and lower gas supply / exhaust ports 40, 42 in a short time (FIG. 3). reference).

  When the temperature of the molding material and the heating units 11 and 12 reaches a predetermined molding temperature equal to or higher than the glass transition point, the process waits until the molding material and the upper and lower mold units 11 and 12 become thermally uniform (waiting process). As shown in FIG. 6, the driving mechanism 20 is driven to move the lower die unit 12 toward the upper die unit 11 and pressurize the moving die 28 to the fixed die 18 as shown in FIG. The material 71 is pressed and this state is continued for a certain time (waiting process). During this time, the on / off of the infrared lamp 36 is controlled so that the mold temperature becomes constant. During this time, the gas supply means continues to supply a small amount of inert gas through the openings 50 and 53. The control unit 25 adjusts the supply amount of the gas supply means within a very small range based on the mold temperature between the heating process and the pressing process. Further, the control unit 25 switches each switch 61 to the exhaust position so that the pressure in the space does not increase between the heating process and the pressing (molding) process, so that the upper and lower gas supply / exhaust ports 40 and 42 are switched. Exhaust slightly (see FIG. 3).

  After a certain period of time, the infrared lamp 36 is turned off to perform slow cooling. In this slow cooling, as shown in FIG. 4, the gas supply means supplies an inert gas to the gas supply passages 49 and 51 to cool the upper and lower mold units 11 and 12 and the molded product, and each switch 61 Is switched to the exhaust position and exhaust is performed from the upper and lower gas supply / exhaust ports 40 and 42. At this time, since the heating unit 13 is maintained at the heating position, the atmosphere of the space including the upper and lower mold units 11 and 12 and the periphery thereof is maintained in an inert gas atmosphere. In addition to the supply of the inert gas from the gas supply paths 49 and 51, the weak lighting of the infrared lamp 36 may be controlled so as to create a predetermined temperature gradient during the slow cooling.

  When the molded product and the upper and lower mold units 11 and 12 are cooled to a temperature below the glass transition point, the drive mechanism 20 is driven to retract the lower mold unit 12 from the upper mold unit 11 as shown in FIG. Open the mold. Thereafter, as shown in FIG. 5, the heating unit 13 is moved to the non-heating position. In conjunction with this movement, the partition member 14 is displaced to the extended state, and the partition member 14 shields the space. At the same time or after a lapse of a certain time, the gas supply means stops supplying the inert gas to the gas supply paths 49 and 51, and each supply / exhaust switching mechanism 60 switches the switch 61 to the supply position, The inert gas is supplied to the space from the gas supply / exhaust ports 40 and 42. The supply amount at this time is larger than the supply of the inert gas supplied from the gas supply means to the gas supply paths 49 and 51 during the slow cooling (see FIG. 3).

  Since the inert gas supplied from the upper and lower gas supply / exhaust ports 40 and 42 merges around the upper and lower mold units 11 and 12 in an open state, the upper and lower mold units 11 and 2 and The surrounding atmosphere can be maintained in a high concentration inert gas atmosphere. Moreover, since the space shielded by the partition member 14 has a higher pressure than the outside air, the outside air does not enter from the entrance / exit 14a.

  After the supply / exhaust switching mechanism 60 switches to gas supply, as shown in FIG. 8, the robot arm 70 enters and exits through the inlet / outlet port 14a and takes out the molded product 73 from the lower mold unit 12. At this time, the upper and lower mold units 11 and 12 are at a high temperature below the glass transition point. However, since the atmosphere of the space shielded by the partition member 14 is maintained in an inert gas atmosphere, oxidation of the mold and the surrounding metal members can be prevented. In this state, a new molding material 71 is supplied for the next molding as shown in FIG. In the heating process at the time of the next molding, since the upper and lower mold units 11 and 12 and their surroundings are kept at a high temperature, they can be rapidly heated to a temperature higher than the glass transition point.

An optical glass having a refractive index (nd) of 1.50 or more, an Abbe number (νd) in the range of 60 to 65, and a glass transition point (Tg) in the range of 500 to 580 ° C. For example, molding was performed using a polishing preform material of K-PBK40 (Sumita Optical Co., Ltd.) as the molding material 71. The viscosity of the glass, which does not cause a problem even if the molded product is taken out from the mold, may be at least 10 ^11.5 dPa · s or more. According to the experiment, as shown in FIG. 3, even if the molded product is taken out when the temperature of the upper and lower mold units 11 and 12 is in the range of 300 to 500 ° C. (temperature below the glass transition point), the mold is oxidized. I found that there was no. As a result, the rapid cooling step can be omitted and the heating time can be shortened. Therefore, the cycle time related to the molding could be shortened to about 2/3 as compared with the prior art described in FIG. 3 schematically shows the supply / stop timing of the gas supply means, the supply / exhaust switching timing of the supply / exhaust switching mechanism 60, and the respective gas supply amounts.

    In the above embodiment, the gas supply / exhaust port 40 is attached to the heating unit 13 and moved together with the heating unit 13. However, the present invention is not limited to this, and as shown in FIG. A fixed cylinder 45 that holds the shaft 16 may be provided, and a gas supply / exhaust port 40 may be fixedly provided below the fixed cylinder 45 so as to be supplied / exhausted from around the fixed shaft 16. Further, as the partition member, as shown in FIG. In this case, the lower end of the shielding cylinder 46 may be slidably supported by the lower support plate 41. Reference numeral 46 a is an entrance / exit provided in the shielding cylinder 46.

  In each of the above embodiments, the non-heating position of the heating unit 13 is set above the upper / lower mold units 11 and 12, but may be set below. In this case, the partition member 14 may be attached on the heating unit 13. Furthermore, the heating means is a radiant heat heating means using an infrared lamp, but instead of this, an induction heating means using an induction heating coil may be used.

  Moreover, in each said Example, although the heating unit 13 is moved, you may fix. In this case, a gap for taking out the molded product from the pair of molds is provided between the heating unit. Then, the molding chamber (the space of the present invention) may be created by covering the pair of molds and the heating unit with the outer frame.

  Further, in each of the above embodiments, the lower mold unit 12 is pressed against the upper mold unit 11, but a structure in which the upper mold unit 11 is moved to the lower mold unit and pressed may be used. Furthermore, although it is set as embodiment which obtains a glass molded article from a glass raw material, it is not restricted to this in this invention, For example, the shaping | molding apparatus and method which obtain a resin molded article using a resin material may be sufficient, and as a molded article, it is a lens. Other than that.

It is sectional drawing which shows the outline of the lens shaping | molding apparatus which employ | adopted this invention, and has shown the process of supplying a shaping | molding raw material. It is sectional drawing which shows the lens shaping | molding apparatus of the state which moved the heating unit to the heating position at the heating process. It is a graph which shows the type | mold temperature with respect to each process. It is sectional drawing which shows the outline of the lens shaping | molding apparatus at the time of the start of a slow cooling process. It is sectional drawing which shows the lens shaping | molding apparatus which shows the state which moved the heating unit to the non-heating position after the mold opening in the middle of a slow cooling process. It is sectional drawing which shows the lens shaping | molding apparatus in a press process. It is sectional drawing which shows the lens shaping | molding apparatus of the state which opened the type | mold in the middle of the slow cooling process. It is sectional drawing which shows the lens shaping | molding apparatus in a molded article extraction process. It is sectional drawing which shows the lens shaping | molding apparatus of the other example using the other example of the opening of a supply / exhaust gas switching mechanism, and the shielding cylinder which does not expand-contract. It is a graph which shows the mold temperature with respect to each process in the conventional lens shaping | molding apparatus demonstrated by the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens molding apparatus 11 Upper mold unit 12 Lower mold unit 13 Heating unit 14 Shrinking member 14a Entrance / exit 60 Supply / exhaust switching mechanism

Claims (10)

  A pair of molds, a heating unit for heating a molding material placed between the pair of molds, a pressing means for pressing the heated molding material to form a molded product, and the pair of molds and their surroundings A partition member for partitioning the space, a gas supply means for supplying an inert gas into the space through the inside of the pair of molds, an inert gas supply having an opening exposed in the space, and the opening A molding apparatus comprising: a supply / exhaust switching mechanism for switching between exhaust in the space. The gas supply means supplies an inert gas into the space when slowly cooling the pair of molds and the molded product,
The supply / exhaust switching mechanism exhausts the space through the opening during the slow cooling, and supplies an inert gas into the space through the opening when taking out a molded product from at least the pair of molds. The molding apparatus according to claim 1.   The molding apparatus according to claim 1, further comprising a control unit that individually controls an operation of the gas supply unit and an operation of the supply / exhaust switching mechanism.   4. The molding apparatus according to claim 1, wherein the openings are provided on both sides of the pair of molds.   The flow path of the inert gas connected to the opening allows the inert gas to flow in both directions, and allows a larger amount of inert gas to flow than at least the flow path of the inert gas connected to the gas supply means. The molding apparatus according to claim 1, wherein the molding apparatus is a road. A support means for supporting the heating unit movably between a heating position surrounding the pair of molds and a non-heating position that moves in parallel with the pressing direction of the pressing means and then retreats;
A holding member that holds heating means constituting a part of the heating unit and shields the space at the heating position;
A partition member that shields the space in association with the heating unit moving toward the non-heating position;
The molding apparatus according to any one of claims 1 to 5, further comprising:   The heating means includes a cylindrical heat ray-permeable inner wall arranged on the inside so as to face the pair of molds, and a plurality of arranged arranged side by side in the pressurizing direction outside the heat ray-permeable inner wall. The molding apparatus according to claim 6, further comprising: an infrared lamp, wherein the heat ray permeable inner wall constitutes a part of the holding member.   8. The holding member is provided with a part of the opening so that the inert gas supplied into the space passes through the front surface of the heat ray permeable inner wall. Molding equipment. A heating step of heating a molding material placed between a pair of molds with a heating unit, a pressing step of pressing the heated molding material with a pressing means to mold a molded product, and the pair of molds and molding In a molding method having a slow cooling step of gradually cooling a product, and a molded product taking out step of taking out a molded product from the pair of molds,
In the slow cooling step, the pair of molds and the space around them are partitioned by a partition member, while supplying an inert gas into the space partitioned by the partition member through the inside of the pair of molds, Exhausting the space through an opening exposed in the space by a supply / exhaust switching mechanism;
In the molded product removing step, the supply / exhaust switching mechanism includes a step of supplying an inert gas into the space through the opening. A step of placing a molding material between the pair of molds; a heating step of heating the pair of molds and the molding material by a heating unit disposed at a heating position that shields the pair of molds and the space around the mold; A pressing step of pressing the one mold toward the other mold by a pressing means to mold the molding material, a slow cooling step of slowly cooling the pair of molds and the molded product after molding, and the slow cooling after the cooling In a molding method for continuously molding a molded product by repeatedly performing a cycle consisting of a molded product take-out step of taking out the molded product from a pair of molds,
At the start of the slow cooling step, an inert gas is supplied to the space shielded by the heating unit through the inside of the pair of molds by a gas supply means, and is exposed to the space by a supply / exhaust switching mechanism. Evacuating the space through the opening;
In the molded product removal step, the heating unit is moved from the heating position to a non-heating position where the heating unit is retracted in parallel with the pressing direction of the pressing means, and the partition member is displaced to a shielding state in conjunction with the movement. The partition member shields the space, and the supply / exhaust switching mechanism switches the exhaust pipe connected to the opening to the supply pipe to supply the inert gas to the space. Taking out the molded product through an inlet / outlet provided in the partition member while maintaining an oxygen-free state,
A molding method comprising:

Images