Abstract:
A mold set according to embodiment comprising: a die including a plurality of parts and holding a molded material; and a back plate laid below the die.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2013-108158, filed May 22, 2013, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a mold set and, for example, relates to a mold set configured to move between a plurality of handling units. 
     2. Description of the Related Art 
     Among molding apparatuses for pressure-molding a molded material by heat softening, an apparatus of the moving mold type in which the molding cycle is shortened by moving a mold set holding the molded material between a plurality of units, each of which performing heating treatment, a press molding process, or a cooling process, to advance each process of heating, molding, and cooling on a plurality of molded materials in parallel is known (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2007-131489). 
     The mold set generally includes an upper die and a lower die holding a molded material and a sleeve covering an outer circumferential portion of the upper die and the lower die. If movement, heat treatment, or a press process is performed on such a mold set, the mold set is likely to be damaged by a mechanical or thermal impact. 
     BRIEF SUMMARY OF THE INVENTION 
     A mold set according to an embodiment includes a die to hold a molded material by including a plurality of parts and a back plate laid below the die. 
     According to the present invention, a high-level of transportability can be ensured by preventing damage by a mechanical or thermal impact. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is an explanatory view schematically showing the configuration of a molding apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a side view schematically showing the configuration of the molding apparatus. 
         FIG. 3  is a plan view schematically showing the configuration of the molding apparatus. 
         FIG. 4  is a plan view showing a mold set according to the embodiment. 
         FIG. 5  is a V-V sectional view of  FIG. 4 . 
         FIG. 6  is a VI-VI sectional view of  FIG. 4 . 
         FIG. 7  is a bottom view of a back plate of the mold set according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     [First Embodiment] 
     A mold set according to the first embodiment of the present invention will be described below with reference to  FIGS. 1 to 7 . In each figure, the configuration is schematically shown by scale-up, scale-down, or omission when appropriate. 
     A molding apparatus  10  shown in  FIGS. 1 to 3  is the molding apparatus  10  that molds a molded material  1  such as a glass by a press process after the molded material being softened by heating treatment and manufactures a molded product  2  including cover glass for, for example, smartphones or tablet terminals. 
     The molding apparatus  10  includes a press unit  40  that performs a press molding process on the molded material  1  by applying pressure to the molded material  1  or a mold set  20  holding the molded product  2  as a molded product, a heating unit  30  that applies heat to the molded material  1  by heating the mold set  20  before the press molding process, a slow cooling unit  50  (cooling unit) that performs a slow cooling process while holding pressure of the molded product  2  after the molding process being performed thereon by the press unit  40 , a rapid cooling unit  60  (cooling unit) that performs a rapid cooling process on the molded product  2  on which the slow cooling process has been performed, a transport unit  70  that transports the mold set  20 , a carrying-in unit  80  and a carrying-out unit  90  provided on both ends of a transportation route along an arrow in the figure respectively, an isolation chamber  11  that accommodates these units  30 ,  40 ,  50 ,  60 ,  70 ,  80 ,  90  and also isolates these units from the outside atmosphere, and a control unit  12  that controls the operation of each of these units  30 ,  40 ,  50 ,  60 ,  70 ,  80 ,  90  and the isolation chamber  11 . 
     In this configuration (embodiment), a heating station in which a plurality of the heating units  30  is contiguously arranged in parallel, a press station in which a plurality of the press units  40  is contiguously arranged in parallel, a slow cooling station in which the slow cooling unit  50  is arranged, and a rapid cooling station in which the rapid cooling unit  60  is arranged are arranged along the transportation route. 
     The lower plate of each unit in each station is contiguously arranged in parallel along the transportation route. A path through which the mold set  20  passes is formed on a sequence of plates. A plurality of the mold sets  20  is moved by the transport unit  70  successively from the upstream side to the downstream side along the path on the sequence of plates. 
     Regarding a plurality of the units  30 ,  40 ,  50 ,  60 , the carrying-in unit  80 , the four heating units  30 , the three press units  40 , the one slow cooling unit  50 , the two rapid cooling units  60 , and the carrying-out unit  90  are arranged in parallel at equal intervals (unit pitch) P 1  in this order from one end (right side in  FIG. 1 ) in a transportation direction along the X axis. Each of these units  30 ,  40 ,  50 ,  60  is configured to be able to be rearranged and increased/decreased. 
     As shown in  FIGS. 4 to 6 , each of the mold sets  20  includes an upper mold  21  (upper die) formed in accordance with an upper shape of the molded product  2 , a lower mold  22  (lower die) arranged opposite to the upper mold  21  and formed in accordance with a lower shape of the molded product  2 , a sleeve  23  that surrounds and supports the outer side of the upper mold  21  and the lower mold  22 , and a back plate  24  laid below the lower mold  22 . 
     The upper mold  21  and the lower mold  22  form a rectangular shape of a predetermined size having a cavity corresponding to the shape of the molded product  2  in a closed state. The molded material  1  in, for example, a plate shape is arranged between the upper mold  21  and the lower mold  22 . A material having excellent heat resistance and material strength of high temperature is used as the material of the upper mold  21  and the lower mold  22 . For example, glassy carbon, graphite, C/C composite or the like is used. 
     The upper mold  21  has, as shown in, for example,  FIG. 5 , a step shape in which an upper portion protrudes to the outer side more than a lower portion. 
     The lower mold  22  includes a protruding portion  22   a  in a collar shape protruding to the outer side on an outer circumference thereof. As shown in, for example,  FIG. 5 , the lower mold  22  has a step shape in which the lower portion protrudes to the outer side more than the upper portion and the lower portion constitutes the protruding portion  22   a.    
     The upper mold  21  and the lower mold  22  are inserted into an installation portion  23   a  of the sleeve  23  in a rectangular shape and supported. 
     The sleeve  23  is made of a heat-resistant material such as graphite, C/C composite, carbide, tungsten alloys or the like and configured in a rectangular frame shape. The installation portion  23   a  into which the upper mold  21  and the lower mold  22  are inserted and held is formed in the center portion of the sleeve  23 . The sleeve  23  forms a step shape opposed along the outer surface of the upper mold  21  and the lower mold  22  and the upper mold  21  and the lower mold  22  are positioned in predetermined positions by the step. 
     A pair of connecting pins  25  (connecting portions) protruding in the transportation direction is formed on end faces on both sides in the transportation route direction of the sleeve  23 . The connecting pin  25  is an axis body configured by a material, for example, silicon nitride (Si 3 N 4 ), stainless steel or the like whose thermal conductivity is small and the connecting pins  25  arranged in neighboring units come into contact contiguously in the transportation direction to convey an extruding force by the transport unit  70  described later. For example, a total of the four connecting pins  25 , two pins on both sides in the width direction of the transportation route on each of both sides in the transportation direction, are provided. 
     The length of the sleeve  23  in the transportation direction including the connecting pin  25  on both sides is set to the same length as the unit pitch P 1 , which is the inter-unit interval of the carrying-in unit  80 , the heating unit  30 , the press unit  40 , the slow cooling unit  50 , the rapid cooling unit  60  and the carrying-out unit  90 . That is, the connecting pin  25  is configured such that the connecting pins  25  of the mold sets  20  placed in neighboring units come into contact with each other and are contiguous. 
     The back plate  24  is configured in a rectangular plate shape having a fixed thickness and is arranged below the lower mold  22 . The back plate  24  is made of a material, for example, molybdenum, tungsten allows, C/C composites or the like. 
     As shown in  FIGS. 4 and 6 , the back plate  24  is fastened to the sleeve  23  by a fixture such as a bolt B on both sides in the width direction perpendicular to the transportation direction of the mold set  20 . With this fixing of the back plate  24  and the sleeve  23 , the protruding portion  22   a  is sandwiched between the step of the sleeve  23  and the back plate  24  in a space formed therebetween and the lower mold  22  is positioned and fixed. 
     A guide portion  24   a  having an inclined plane inclined with respect to the up and down direction and the transportation direction is provided on both ends in the transportation direction on the undersurface of the back plate  24 . The guide portion  24   a  is set to an inclination of, for example, 10° to 20. Thanks to the guide portion  24   a , extruded transportation of the mold set  20  is made smooth between top surfaces of plates of neighboring units. 
     As shown in  FIG. 7 , a plurality (here, five) of grooves  24   b  for air vent is formed on the undersurface of the back plate  24 . Each of these grooves  24   b  extends in parallel along the transportation direction. The groove  24   b  reduces sliding friction to enable a smooth transportation process that slides the back plate  24  along the transportation direction. 
     Each of the plurality of heating units  30  arranged in parallel in the transportation direction includes an upper heater unit  31  and a lower heater unit  32  arranged vertically like sandwiching the mold set  20  therebetween. Each of the upper heater unit  31  and the lower heater unit  32  has a plurality of rows of infrared lamps  34  arranged as a heater mechanism. 
     A mounting plate  35  on which the mold set  20  is placed is fixed on the rows of the lower infrared lamps  34 . The mounting plate  35  is made of a material, for example, SiC or the like having high thermal conductivity and is configured in a rectangular plate shape. The heating unit  30  configured as described above applies heat while the mold set  20  successively transported by the transport unit  70  is placed on the lower mounting plate  35 . 
     Each of the plurality of press units  40  arranged in parallel in the transportation direction includes a pair of upper and lower press plates  46  arranged like sandwiching the mold set  20  therebetween. Each of the press plates  46  is configured in a rectangular plate shape and is formed of a material such as carbide or SiC having high thermal conductivity and acting as a rigid material. An infrared lamp  45  is provided in the press plate  46  as a heater mechanism. A press axis  42  is connected to the upper press plate  46 . The press axis  42  is connected to an ascent/descent mechanism unit  43  such as a servo motor, an air cylinder or the like and is configured to move vertically in accordance with the control of the control unit. 
     The press unit  40  configured as described above applies heat to the mold set  20  set up between the pair of plates  46  by the infrared lamp  45  and also a press process to apply pressure to the mold set  20  between the pair of plates  46  is performed by lowering the upper press plate  46  by ascent/descent movement of the upper press plate  46 . 
     The slow cooling unit  50  arranged in parallel in the transportation direction as a first cooling unit includes upper and lower slow cooling plates  51  (cooling units) arranged vertically like sandwiching the mold set  20  therebetween. 
     The upper and lower slow cooling plates  51  are configured in a rectangular plate shape and is formed of a material such as carbide or SIC having high thermal conductivity and acting as a rigid material. The upper and lower slow cooling plates  51  have an infrared lamp  56  incorporated as a heater mechanism for slow cooling. A path for the mold set  20  to pass is formed between the upper and lower slow cooling plates  51 . 
     The lower slow cooling plate  51  is configured just like the lower press plate  46 . The upper slow cooling plate  51  has, like the upper press plate  46 , a press axis connected thereto and is configured to be able to ascend and descend by an ascent/descent mechanism unit  63 . 
     A slow cooling process is performed while holding pressure that maintains a fixed pressing force by lowering the upper slow cooling plate  51  by the ascent/descent mechanism unit  63  and applying pressure to the mold set  20  put on the lower slow cooling plate  51 . 
     The rapid cooling unit  60  as a second cooling unit includes upper and lower cooling plates  61  (cooling units) arranged vertically like sandwiching the mold set  20  therebetween, a support axis  62  extending in the up and down direction by being linked to the upper cooling plate  61 , and the ascent/descent mechanism unit  63  such as a servo motor, an air cylinder or the like connected to the upper cooling plate  61 . 
     The upper and lower cooling plates  61  are configured in a rectangular plate shape and is formed of a material such as carbide, SiC, hardened stainless or the like having high thermal conductivity and acting as a rigid material. The cooling plates  61  have a refrigerant pipe constituting a channel allowing a coolant to flow incorporated thereinto. In addition, each of the upper and lower cooling plates  61  is provided with a plurality of thermocouples. Further, the upper cooling plate  61  is configured to be able to ascend and descend vertically by the ascent/descent mechanism unit  63 . 
     A rapid cooling process is performed by lowering the upper cooling plate  61  by driving the ascent/descent mechanism unit  63  and applying pressure to the mold set  20  put on the lower cooling plate  61  after coming into contact therewith. 
     Incidentally, a thermocouple is provided in each of the units  30 ,  40 ,  50 ,  60  and the temperature in the course of process is detected and used for feedback control by the control unit  12 . 
     As shown in  FIGS. 1 to 3 , the carrying-in unit  80  is provided on one end side in the transportation direction, that is, next to the heating unit  30  (right side in the figures). The carrying-out unit  90  is provided on the other end side in the transportation direction, that is, downstream side of the rapid cooling unit  60 . 
     The transport unit  70  includes a cylinder shaft  71  that reciprocates along the transportation direction, an air cylinder  72  for transportation as an extruding mechanism that moves the cylinder shaft  71  in the transportation direction by being connected to the control unit, and a stopper portion  73  that regulates the position of the mold set  20  on the downstream side in the transportation direction. 
     The cylinder shaft  71  extends coaxially with the connecting pin  25 . The air cylinder  72  for transportation is installed on an end of the carrying-in side of the isolation chamber  11  and has a function of extruding the connecting pin  25  in a fixed stroke along the transportation direction. With each of the mold sets  20  being extruded in the transportation direction by accompanying movement of the extruded connecting pin  25 , the plurality of mold sets  20  is successively transported together from the one end side to the other end side in a fixed stroke. 
     The carrying-in unit  80  includes a carrying-in plate  81  on which the mold set  20  is placed to move by ascending or descending, a load lock chamber  82  provided in the upper portion of the carrying-in station, an ascent/descent mechanism unit  83  that moves the carrying-in plate  81 , and a movement mechanism unit  84  provided in the lower portion of the load lock chamber  82 . 
     The carrying-out unit  90  is arranged on the other end side in the transportation direction, that is, downstream side of the rapid cooling unit  60 . The carrying-out unit  90  includes a carrying-out plate  91  on which the mold set  20  is placed to move by ascending or descending, a load lock chamber  92  provided in the upper portion of the carrying-out station, an ascent/descent mechanism unit  93  that moves the carrying-out plate  91 , and a movement mechanism unit  94  provided in the lower portion of the load lock chamber  92 . 
     Further, outside the isolation chamber  11  of the molding apparatus  10 , a molded product stocker  13  that holds a plurality of the molded products  2 , a mold stocker  14  that holds a plurality of the mold sets  20  or dummy mold sets  20 A, and a material stocker  15  that stores the molded material  1  are provided. 
     A procedure for manufacturing the molded product  2  from the molded material  1  by using the molding apparatus  10  according to the present embodiment will be described below. As an example of the molded product  2 , for example, cover glass for a smartphone of 4 to 12 inches in size and the thickness of about 0.3 to 1.5 mm can be cited, but the molded product is not limited to such an example and can be applied to various shapes and uses. For example, the molded product  2  in a shape in which both end portions are curved or in a shape in which the thickness of ends changes can also be formed from the molded material  1  in, for example, a plate shape. 
     In the molding apparatus  10 , a plurality of processes is performed by a plurality of units in parallel by arranging the one mold set  20  in each unit, but for the description below, the procedure focuses on the one mold set  20 . 
     That is, a process on the one mold set  20  is performed by one unit and a process on the other mold set  20  is performed by another handling unit. In  FIGS. 1 to 3 , a case in which the one mold set  20  is arranged in each unit is shown. 
     First, the molded material  1  of the material stocker  15  is set to the mold set  20  of the mold stocker  14 . 
     As the carrying-in process, the mold set  20  is set into the load lock chamber  82  and the load lock chamber  82  is closed. Next, the mold set  20  is lowered by the ascent/descent mechanism unit  83 . After being lowered, the mold set  20  is horizontally moved by the movement mechanism unit  84  up to the position where the mold set is extruded by the transport unit  70 . 
     When the mold set  20  is moved from the stocker  14  to the load lock chamber  82 , for example, the mold set  20  is gripped by a robot arm for transportation and moved. In this case, the mold set  20  can be moved without the upper mold  21  and the lower mold  22  being damaged by the sleeve  23  and the back plate  24  being gripped. 
     The control unit  12  drives the cylinder shaft  71  in predetermined timing when processes of other units such as the heating unit  30  are completed to move the mold set  20  to the downstream side by a pitch P 2  obtained by adding a fixed distance to the unit pitch P 1  by pressing against the connecting pin  25  of the mold set  20  to move the mold set  20  onto the first mounting plate  35  of the heating unit  30  (transportation process). At the same time, a plurality of the mold sets  20  arranged on the downstream side is also extruded by the connecting pin  25  to move to the downstream side by the unit pitch P 1 . That is, the connecting pins  25  of the plurality of mold sets press against the mold sets  20  on the downstream side and so the cylinder shaft  71  moves the mold sets  20  simultaneously. 
     In the first heating unit  30 , the mold set  20  is heated by the upper and lower infrared lamps  34  to soften the molded material  1  at a predetermined temperature (heating treatment). The mold sets  20  are successively sent to the downstream side by the same transportation process as described above in the timing when a plurality of parallel processes is completed to repeat the heating treatment in the same manner. 
     Next, the plurality of mold sets  20  is moved to the downstream side together by the same transportation process to transport the mold set  20  to the first press unit  40  from the heating unit  30  on the downstream side. 
     The control unit  12  drives the ascent/descent mechanism unit  43  of the press unit  40  to lower the upper press plate  46  and performs press molding by sandwiching the mold set  20  between the upper and lower press plates  46  while heating the molded material  1  (press process). The mold sets  20  are successively sent to the downstream side by the same transportation process as described above in the timing when a plurality of parallel processes is completed to repeat the press process in the same manner by the press unit  40  on the downstream side. 
     Subsequently, the mold set  20  is transported to the first slow cooling unit  50  from the press unit  40  on the downstream side by the same transportation process. In the slow cooling unit  50 , the mold set  20  is treated to have a predetermined temperature by, for example, adjusting the temperature using heaters while the pressure is held by a pair of the slow cooling plates  51  (slow cooling process). 
     Next, the mold set  20  is transported from the slow cooling unit  50  to the rapid cooling unit  60  by the same transportation process as described above. The control unit  12  drives the ascent/descent mechanism unit  63  of the rapid cooling unit  60  to lower the upper cooling plate  61  and cools the mold set  20  to a temperature range in which oxidation is prevented even in the atmosphere by sandwiching the mold set  20  between the upper and lower cooling plates  61  (rapid cooling process). 
     Subsequently, the transportation process is performed. As the transportation process, the mold set  20  is first moved to the downstream side by a pitch P 3  obtained by adding a fixed distance to the unit pitch P 1  by a movement mechanism unit  76  provided by the transportation path and then horizontally moved to a position just below the load lock chamber  92  by the movement mechanism unit  94 . Thereafter, the mold set  20  is moved upward by the ascent/descent mechanism unit  93 . When the mold set  20  is moved to the load lock chamber  92 , the load lock chamber  92  is opened and the mold set  20  is fetched. 
     The carried-out mold set  20  is disassembled outside the isolation chamber  11  and the fetched molded product  2  is set to the molded product stocker  13 . The new molded material  1  is set to the used mold set  20  to repeat the above molding process. 
     When the mold set  20  is moved from the carrying-out position to the stocker  14 , for example, the mold set  20  is gripped by a robot arm for transportation to be moved. In this case, the mold set  20  can be moved without the upper mold  21  and the lower mold  22  being damaged by the sleeve  23  and the back plate  24  being gripped. 
     According to the present embodiment, with the back plate  24  provided below the lower mold  22 , transportability can be improved by securing the height of the mold set  20  while the thickness of the upper mold  21  and the lower mold  22  being reduced. Generally, if the material structure of glassy carbon is not uniform, the stress inside the structure is biased after an impact being received and thus, when glassy carbon is used as the material of the mold, a difference of internal structure is more likely to arise with an increasing thickness and also a damage phenomenon such as breakage and chipping is more likely to occur. Therefore, the thickness of the mold is limited to prevent breakage depending on the material and it is more difficult to transport the mold with a less total height of the mold, but according to the present embodiment, by providing the back plate  24  on the back surface of the lower mold  22 , transportability can be improved by securing the height of the mold set  20  while damage being avoided regardless of the material of the lower mold  22 . 
     In the present embodiment, damage of the lower mold  22  can be prevented by sliding movement of the back plate  24  on plates arranged in parallel. Also by contiguously providing the connecting pins  25  protruding in the transportation direction in the mold set  20 , process efficiency can be increased by transporting a plurality of the mold sets  20  together. 
     Also according to the present embodiment, by adopting a configuration in which the sleeve  23  and the back plate  24  are fixed by the bolt  5  across a protruding portion of the lower mold  22 , the sleeve and the back plate can be fixed without a fixing structure such as a screw hole or the like being formed in the lower mold  22 . 
     Further, in the above embodiment, by providing the guide portion  24   a  on the undersurface of the back plate  24 , smooth sliding movement in the traveling direction is enabled without being prevented by a step between plates arranged in parallel. Also, by providing the grooves  24   b  for air vent on the undersurface of the back plate  24 , smooth sliding movement in the traveling direction is enabled without the back plate  24  being adsorbed by the heating treatment or pressurization process so that transportability can be improved. 
     In the present embodiment, the mold body of the mold set  20  has a two-piece configuration of the upper mold  21  and the lower mold  22 , but a three-piece configuration of an upper mold, a middle mold, and a lower mold may also be adopted. 
     The present invention is not limited to each of the above embodiments and can be carried out by making appropriate alterations. Also, the present invention can be carried out by combining features of a plurality of embodiments. In addition, various modifications can naturally be made within the scope of the present invention.