JP2006169009A - Molding method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a high-grade product with which the temperature difference between upper and lower dies can be controlled during a pressing process in press molding, and to realize a cost reduction of the apparatus. <P>SOLUTION: In the molding apparatus of performing press molding by arranging a preform material 4 into dies consisting of a barrel die 1, and upper and lower dies 2a, 2b arranged therein, heating the barrel die 1, the upper and lower dies 2a, 2b and the preform material 4 by an induction heating coil 3 disposed around the same, and moving at least either of the upper and lower dies by a press shaft 5; an interlocking mechanism, such as a height adjusting mechanism 11, is connected to the press shaft 5 to move at least either of the upper and lower dies to apply a load thereto and the induction heating coil 3 is attached to the interlocking mechanism and the induction heating coil 3 is moved mechanically cooperatively with the movement of the press shaft 5 during press molding so that the temperature difference between the upper and lower dies 2a, 2b can be controlled at the time of the press molding by the simple mechanism. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molding method and apparatus for obtaining a product such as an optical element by press molding a material.

  Conventionally, optical lenses such as cameras have been manufactured by a process such as polishing, but in recent products using optical elements such as DSCs, video cameras, and laser printers, higher functionality, smaller size, and lighter weight. In order to reduce the cost, aspherical lenses are often used. Furthermore, a glass press molding method is employed for manufacturing a high-performance glass aspheric lens that cannot be handled by a resin aspheric lens by injection molding. The manufacturing method itself of the optical lens by such glass press molding is known conventionally (for example, refer patent document 1 and patent document 2).

  A general apparatus configuration and manufacturing process for conventional lens molding will be described with reference to FIGS. In FIG. 3, the lens molding apparatus includes a cylindrical body mold 21, an upper mold 22 a fixed in the body mold 21, and a lower mold disposed so as to be movable in the body mold 21 with respect to the upper mold 22 a. 22b, and a lens preform material 24 is supplied between the upper mold 22a and the lower mold 22b.

  An induction heating coil 23 for inductively heating the trunk mold 21, the upper mold 22a, and the lower mold 22b is disposed outside the trunk mold 21. The upper die 22a is fixed to a fixed upper press shaft 25, and the lower die 22b is pressurized by a movable lower press shaft 26. A frame 27 on which the induction heating coil 23 is mounted is supported by a slide plate 28. The slide plate 28 is supported by a slide guide 29 so as to be movable in parallel with the axial direction of the lower press shaft 26. The slide guide 29 reciprocates by rotating the screw shaft 31 forward and backward by a drive mechanism such as a motor 30. Moved. As shown in FIG. 4, the upper and lower stoppers 33 a and 33 b and the air cylinder device 34 may be used without using the motor 30. However, since it can be driven only in one direction, it is difficult to synchronize with the press operation.

  Temperature sensors 32a and 32b are attached to the upper mold 22a and the lower mold 22b, respectively. As shown in FIG. 5, the temperature sensors 32 a and 32 b are connected to the corresponding temperature / voltage conversion circuits 35 a and 35 b, and the outputs of these two circuits are input to the temperature difference calculation circuit 36. The temperature difference signal output from the temperature difference calculation circuit 36 is input to the up / down operation circuit 37, and the up / down operation circuit 37 outputs a difference signal between a command temperature difference given as a set value and the temperature difference signal. The difference signal is input to the positioning circuit 39 via the PID controller 38 and the motor 30 is driven and controlled via the motor driver 40 to move the induction heating coil 23 up and down. The detected values of the temperature sensors 32a and 32b are input to the induction heating output control circuit 41 via the PID controller 38, and the induction heating coil 23 is controlled so that the mold temperatures of the upper and lower molds 22a and 22b are set to desired values. Is configured to do.

  Next, the molding process will be described. The upper die 22a is fixed, the lower press shaft 26 is lowered, and the preform material 24 is placed on the lower die 22b. As shown in FIG. 3, the lower press shaft 26 is raised to the preheating position, and heating by the induction heating coil 23 is started. The output of the coil is controlled so that the detection value of the temperature sensor 32b of the lower mold 22b becomes a desired value, and the upper and lower molds 22a and 22b and the preform material 24 are heated.

  At this time, the upper and lower molds 22 a and 22 b usually generate a temperature difference due to the difference in the relative axial position with respect to the induction heating coil 23. The temperature difference between the upper and lower molds 22a and 22b is calculated by the temperature sensors 32a and 32b, the temperature / voltage conversion circuits 35a and 35b, and the temperature difference calculation circuit 36, and the temperature difference is fed back to the upper and lower operation circuit 37. If there is a difference from the initial set temperature difference, the motor 30 is driven by the PID controller 38, the positioning circuit 39, and the motor driver 40 to move the induction heating coil 23 up and down, and the temperature difference between the upper and lower molds 22a and 22b becomes the set value. Stabilize where it becomes the same. Thus, the upper and lower molds 22 a and 22 b are controlled to a desired temperature by the vertical movement of the induction heating coil 23.

Thereafter, when the pressable temperature is reached, the lower press shaft 26 is raised and the preform material 24 is pressed. At this time, the lower die 22b is strongly heated because the positional relationship with the induction heating coil 23 changes to the center of the coil by the pressing operation. And the temperature difference balance of the upper and lower molds 22a and 22b is broken. This change is detected by the temperature sensors 32 a and 32 b, calculated by the temperature / voltage conversion circuits 35 a and 35 b and the temperature difference calculation circuit 36, and the temperature difference is fed back to the vertical operation circuit 37. Then, the motor 30 is driven and the induction heating coil 23 is moved to stabilize the temperature difference between the upper and lower molds 22a and 22b equal to the set value. By the operation as described above, the upper and lower dies 22a and 22b are press-molded while being maintained at a desired temperature difference by a press device using the induction heating coil 23 as a heat source.
JP-A-5-310434 Japanese Patent Laid-Open No. 5-270847

  By the way, the press molding apparatus that uses the induction heating coil 23 as described above and feedback-controls the temperature difference between the upper and lower dies 22a and 22b by a mechanism that moves the induction heating coil 23 up and down is a temperature difference between the upper and lower dies 22a and 22b. It is effective to realize a desired molding process. However, since the cost of the drive mechanism of the upper and lower molds 22a and 22b and the temperature feedback system increases the price of the molding apparatus, various countermeasures in terms of cost such as multi-cavity and tact reduction are being taken. Nevertheless, there is a problem that the manufacturing cost of a molded article of an optical element such as a lens increases.

  In view of the above-mentioned conventional problems, the present invention can realize a high-quality product by controlling the temperature difference between the upper and lower molds during the pressing process in the manufacture of products such as optical elements by press molding, and has a simple mechanism. An object of the present invention is to provide a molding method and apparatus capable of realizing a low cost.

  The molding method of the present invention includes any of a step of placing a material in a mold comprising a cylindrical body mold and an upper and lower mold disposed therein, a step of heating the material with an induction heating coil, and the upper and lower molds. In this molding method, the material is press-molded by moving either of them, and the induction heating coil is moved in conjunction with the movement of one of the upper and lower molds.

  According to this configuration, the temperature difference between the upper and lower molds can be controlled by moving the induction heating coil in conjunction with the movement of one of the upper and lower molds, and high-quality molding can be performed for products of any shape and material. Can be realized.

  In addition, when the induction heating coil is moved by a movement amount different from the movement amount of one of the upper and lower molds, and the temperature of the upper and lower molds is arbitrarily controlled, the temperature of the upper and lower molds corresponds to the characteristics of the product and the material The difference can be controlled appropriately, and high-quality molding can be realized for products of any shape and material.

  The molding apparatus of the present invention is a molding apparatus comprising a cylindrical body mold, an upper and lower mold disposed therein, and an induction heating coil disposed around the body mold, the upper and lower molds The interlock mechanism is connected to a pressing mechanism that applies a load to the mold, and the induction heating coil is attached to the interlock mechanism.

  According to this configuration, it is possible to control the temperature difference between the upper and lower molds without providing a special induction heating coil moving mechanism by moving the induction heating coil in conjunction with the upper and lower pressing mechanism by the interlocking mechanism. Thus, high-quality molding can be realized for products of any shape and material, and the cost of the apparatus can be reduced by a simple mechanism.

  In addition, the interlock mechanism is equipped with a height adjusting mechanism that is mounted on the pressing mechanism and moves a movable member that is slidable along the pressing mechanism by a cam that operates in conjunction with the movement of the pressing mechanism. When the induction heating coil is connected to the moving member, the induction heating coil is moved by an arbitrary movement amount different from the movement amount of the upper and lower mold pressing mechanisms by adjusting the shape and position of the cam, and the temperature difference between the upper and lower molds is increased. It can be controlled, high-quality molding can be realized for products of any shape and material, and cost reduction of the apparatus can be realized by a simple mechanism.

  According to the molding method of the present invention, the temperature difference between the upper and lower molds can be controlled by moving the induction heating coil in conjunction with one of the upper and lower molds. Can be realized.

  Further, according to the molding apparatus of the present invention, the interlocking mechanism is connected to the pressing mechanism that applies a load to the upper and lower molds, and the induction heating coil is attached to the interlocking mechanism, so that there is no need to provide a special mechanism for moving the induction heating coil. The temperature difference between the upper and lower molds can be controlled, high-quality molding can be realized for products of any shape and material, and the cost of the apparatus can be reduced by a simple mechanism.

  Hereinafter, an optical element molding apparatus according to an embodiment of the molding method and apparatus of the present invention will be described with reference to FIGS.

  In FIG. 1, an optical element molding apparatus includes a cylindrical body mold 1, an upper mold 2a fixed in the body mold 1, and a lower mold body 1 disposed so as to be movable in the body mold 1 with respect to the upper mold 2a. A mold 2b is provided, and a preform material 4 of an optical element is supplied between the upper mold 2a and the lower mold 2b. An induction heating coil 3 for inductively heating the trunk mold 1, the upper mold 2a, and the lower mold 2b is disposed outside the trunk mold 1 so as to surround the trunk mold 1.

  The body mold 1 and the upper mold 2a are attached to a lower end portion of a press shaft 5 that moves up and down by a cylinder device 6 via a heat insulating material 7a. The lower mold 2b is installed and fixed on the molding stage 8 via a heat insulating material 7b. A frame 9 connected to the induction heating coil 3 is supported by a slide bush 10 slidably fitted to the press shaft 5, and the induction heating coil 3 is pressed via the frame 9 and the slide bush 10. It is mounted so that it can move up and down. A height adjusting mechanism 11 for adjusting the height position of the slide bush 10 is fixed to the press shaft 5 and is arranged in cooperation with the fixed side.

  The height adjusting mechanism 11 has a rotatable rotating cam 12. A slide bush 10 is engaged on the rotating cam 12 and is positioned relative to the press shaft 5. The position is adjusted by rotation. An action piece 13 extends from one side of the rotary cam 12. The lower surface of the distal end of the action piece 13 is engaged with an engagement portion 15a at the lower end of the engagement rod 15 suspended from the upper frame 14 on which the cylinder device 6 is installed. A height adjusting screw 16 that engages with the upper surface of the upper frame 14 is screwed together so that the height position of the engaging rod 15 can be adjusted. Thereby, the initial position of the induction heating coil 3 can be adjusted. Further, a tension spring 17 that biases the action piece 13 downward to engage with the engaging portion 15a is interposed between the action piece 13 and the heat insulating material 7a. Thereby, the induction heating coil 3 can be returned to the original position for each press.

  Temperature sensors 18a and 18b are attached to the upper mold 2a and the lower mold 2b, respectively, so that the upper mold 2a and the lower mold 2b can be controlled in temperature and monitored. As shown in FIG. 2, one of the temperature sensors 18a and 18b is input to the induction heating output control circuit 20 via the PID controller 19, and the mold temperature of one of the upper and lower molds 2a and 2b is desired. The induction heating coil 3 is controlled to have a value of.

  Next, the case of controlling the temperature of the lower mold 2b and controlling the mold temperature difference to be equal during the molding process will be described with respect to the molding process and operation of the optical element.

  First, the press shaft 5 is raised and the body die 1 and the upper die 2a are raised together with the induction heating coil 3, and then the preform material 4 is set on the lower die 2b, and the press shaft 5 is again moved to a predetermined preheating position. The mold and the preform material 4 are heated by the induction heating coil. In the temperature control of heating, the temperature detected by the temperature sensor 18b of the lower mold 2b is input to the PID controller 19, and the output of the induction heating output control circuit 20 is controlled by the PID controller 19 to perform feedback control.

  The positional relationship between the upper and lower molds 2a, 2b and the induction heating coil 3 is adjusted by the height adjusting screw 16 while watching the temperature monitor so as to be equal in temperature in advance. Further, the shape of the rotary cam 12 is also calculated in advance from the amount by which the preform material 4 is pushed, and is formed in such a shape that the relative positional relationship between the induction heating coil 3 and the upper and lower molds 2a and 2b does not change. Further, when it is desired to provide a temperature difference, the preheating position is adjusted by the height adjusting screw 16, and the temperature control at the time of pressing is handled by adjusting the shape of the rotating cam 12.

  Thus, at the preheating position shown in FIG. 1, when the body mold 1, the upper and lower molds 2a, 2b, and the preform material 4 are heated to the set temperature, the press shaft 5 is lowered and press-molded. At this time, in the apparatus in which the normal induction heating coil 3 is fixed, the upper mold 2a approaches the lower mold 2b, and the positional relationship between the upper and lower molds 2a and 2b is broken, and the temperature balance is broken. The rotary cam 12 rotates as the shaft 5 descends, and the induction heating coil 3 moves to an appropriate position via the slide bush 10 and the frame 9, so that the relative positions of the upper and lower molds 2 a and 2 b and the induction heating coil 3. The relationship is appropriately adjusted, and the same temperature difference (including the case where the temperature difference is 0) as in preheating can be maintained.

  In the description of the above embodiment, an example in which the rotary cam 12 is provided as the height adjusting mechanism 11 and the rotary cam 12 is rotated in conjunction with the movement of the press shaft 5 by the engagement with the engagement rod 15. Although shown, the interlocking mechanism of the present invention is not limited to such a height adjusting mechanism. For example, a plate cam is provided on the fixed side, and a cam lever provided on the press shaft 5 side is interlocked with the movement of the press shaft 5. Then, the induction heating coil 3 may be moved by swinging.

  Moreover, although the example which uses the induction heating coil 3 as a heating means was shown in the said embodiment, this invention has the same effect, when using other heat sources, such as halogen lamps and resistance heaters other than induction heating. Can do.

  In the molding method and apparatus of the present invention, the temperature difference between the upper and lower molds can be controlled during the pressing process by moving the induction heating coil mechanically interlocked with the movement of the mold during press molding. Moreover, the cost of the apparatus can be reduced by a simple mechanism, which is useful for molding high-performance glass aspherical lenses, other optical elements, or various optical elements made of resin.

It is a schematic block diagram of the lens shaping | molding apparatus in one Embodiment of this invention. It is a control block diagram of the lens shaping apparatus of the embodiment. It is a schematic block diagram of the lens shaping apparatus of a prior art example. It is a schematic block diagram of the principal part of the lens shaping | molding apparatus of another prior art example. It is a control block diagram of the lens shaping apparatus of a prior art example.

Explanation of symbols

1 Body type 2a Upper type 2b Lower type 3 Induction heating coil 4 Preform material 5 Press shaft 9 Frame 10 Slide bush 11 Height adjustment mechanism (interlocking mechanism)
12 Rotating cam 15 Engaging rod

Claims (4)

  Arrangement of a material in a mold comprising a cylindrical body mold and upper and lower molds disposed therein, a process of heating the material with an induction heating coil, and moving the upper and lower molds to move the material A molding method comprising a step of press-molding the induction heating coil, wherein the induction heating coil is moved in conjunction with the movement of one of the upper and lower molds.   The molding method according to claim 1, wherein the induction heating coil is moved by a movement amount different from the movement amount of any one of the upper and lower molds, and the temperature of the upper and lower molds is arbitrarily controlled.   A molding apparatus including a cylindrical body mold, an upper and lower mold disposed therein, and an induction heating coil disposed around the body mold, and a pressing mechanism for applying a load to the upper and lower molds A forming apparatus, wherein an interlocking mechanism is connected, and the induction heating coil is attached to the interlocking mechanism. The interlocking mechanism includes a height adjusting mechanism that is mounted on the pressing mechanism and moves a movable member that is slidable along the pressing mechanism by a cam that operates in conjunction with the movement of the pressing mechanism. The molding apparatus according to claim 3, wherein the induction heating coil is connected to a member.

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