JP2000247657A - Glass shaping machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reproducibility of the temperature of a material to be molded and to shorten the time necessary for the temperature of the material to be formed to attain a target temperature. SOLUTION: This glass form machine has a first core, a second core, a drum mold, a heating device which heats the first core and the second core, a pressurizing device which applies pressurizing force on the second core, a first temperature detector which detects the temperature of the drum mold, a second temperature detector detects the temperature of at least one of the first and second cores and a controller 70 which controls the temperature of the blow mold in a first stage and controls the temperature of the cores in a second stage. An electric power command value W3 diminishes with a start of the first stage and, therefore, the temperature of the blow mold may be prevented from rising extremely higher than the temperature of the cores at the point of the time the temperature of the cores attains the second target temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass forming machine.

[0002]

2. Description of the Related Art Conventionally, in a glass molding machine for molding a molded article made of glass, for example, a lens, a mold apparatus comprising an upper mold core, a lower mold core and a body mold is provided, and an upper mold core is formed. A preform as a molding object which is a prototype of a lens is set between the lower mold core and the preform,
Heat is applied through the mold apparatus, and is deformed by pressing by a pressing mechanism.

In this case, the mold apparatus is heated, and the preform is heated via the mold apparatus.
As a method for heating the mold apparatus, a hot plate heating method (see JP-A-4-164826) and a high-frequency induction heating method (see JP-A-63-170228) are provided. In the hot plate heating method, a hot plate in which a plurality of heaters are embedded approaches or comes into contact with a mold device. When the hot plate is brought close to the mold device, the mold device is heated by convection and radiation, and when the hot plate is brought into contact with the mold device, the mold device is heated by convection, radiation and contact heat transfer. Heated by

In the high frequency induction heating method, a high frequency is generated by a heating device, and the mold device is heated by the induction heating.

[0005]

However, in the above-mentioned conventional glass forming machine, the temperature of the barrel (hereinafter referred to as "barrel temperature") is detected by a temperature detector, and based on the detected barrel temperature. However, it is difficult to make the temperature of the preform the optimum target temperature for molding, and the reproducibility of the temperature of the preform is low. Further, since the overshoot is prevented from occurring in the preform temperature, the time required for the preform temperature to reach the target temperature becomes longer.

[0006] That is, what is actually the object of molding is the preform. When the preform is heated via a mold device, the heat is first transmitted to the body mold, and then the upper mold core and the lower mold are heated. Since the body temperature is transmitted to the mold core, the body mold temperature is always higher than the temperature of the upper mold core and the lower mold core (hereinafter referred to as “core temperature”), and the body temperature rises faster than the core temperature rise.

Therefore, when the body temperature is detected by the temperature detector and feedback control is performed based on the detected body temperature, the difference between the body temperature and the temperature of the preform is large. It is difficult to make the temperature the optimum temperature for molding, and the reproducibility of the temperature of the preform is low. Therefore, it is conceivable to detect a core temperature having a small difference from the temperature of the preform and to perform feedback control based on the detected core temperature. However,
When the feedback control is performed based on the core temperature, when the core temperature reaches the target temperature, the body temperature becomes significantly higher than the core temperature, and the body is excessively thermally expanded,
Due to thermal deformation, the durability of the mold device is reduced.

The present invention solves the above-mentioned problems of the conventional glass forming machine, can improve the reproducibility of the temperature of the molding object, and is necessary for the temperature of the preform to reach the target temperature. It is an object of the present invention to provide a glass forming machine capable of shortening the time and improving the durability of a mold device.

[0009]

For this purpose, in a glass forming machine according to the present invention, a first core and a second core movably disposed opposite to the first core are provided; A body for guiding the second core, a heating device for heating the first and second cores, a pressurizing device for applying pressure to the second core, and detecting a temperature of the body. A first temperature detector, a second temperature detector for detecting the temperature of at least one of the first and second cores, and controlling the temperature of the body in the first step; And a controller for controlling the temperature of the core in the step.

In another glass forming machine according to the present invention, the temperature of the barrel is controlled so that the temperature of the barrel becomes a first target value, and the temperature of the core is controlled by: The operation is performed so that the core temperature becomes the second target value. Then, the first target value is set higher than the second target value. In still another glass forming machine of the present invention, the second step is started when a switching condition set in accordance with the temperature of the core is satisfied.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a conceptual diagram of a glass forming machine according to the embodiment of the present invention, and FIG. 3 is a conceptual diagram of a mold apparatus according to the embodiment of the present invention. In the figure, reference numeral 10 denotes a mold apparatus, which is placed on a mold base 31 serving as an apparatus main body of a glass forming machine, and has a lower mold core 11 as a first core, and a lower mold core. The upper core 12 surrounds the lower core 11 and the upper core 12 as a second core which is disposed to be opposed to the upper core 11 and movably in the vertical direction. A sleeve-shaped body 13 that guides 12 is provided.

The lower mold core 11 includes a large-diameter head portion 11a disposed in contact with the mold base 31, and the head portion 1a.
It comprises a small diameter shaft portion 11b integrally formed with the shaft portion 1a, and a molding surface S1 is formed on the upper end of the shaft portion 11b. The upper die core 12 includes a large-diameter head portion 12a and a small-diameter shaft portion 12b formed integrally with the head portion 12a, and a molding surface S2 is formed at a lower end of the shaft portion 12b. The molding surfaces S1 and S2 are formed in correspondence with the shape of a glass molded product (not shown), for example, a lens.
Therefore, the preform 15 as a molded object is set on the lower mold core 11, and in the heating step, the preform 15 is heated via the mold device 10, and the temperature of the preform 15 is set to a predetermined target temperature. When a pressing force is applied to the mold apparatus 10 in the direction of arrow A shown in FIG. 3 in the pressing step, the preform 15 is sandwiched between the lower mold core 11 and the upper mold core 12, and the molding surfaces S1, S2 The lens is shaped according to the shape of the lens.

When the lower die core 11 and the upper die core 12 are inserted facing each other, the inner peripheral surface of the body die 13 is
The shaft portions 11b and 12b are processed so that alignment can be performed with predetermined accuracy by fitting (fitting). The glass forming machine applies a pressing force to the mold clamping device 50 and the mold device 10 that press the body mold 13 against the mold platform 31 to improve the contact state between the mold device 10 and the mold platform 31. A pressing device 60 that presses the upper mold core 12 downward to deform the preform 15 and the lower mold core 1
1, a heating device 40 for heating the preform 15 by heating the upper mold core 12 and the body mold 13.

The heating device 40 comprises an annular upper plate 35, a cylindrical side plate 36, a disk-shaped lower plate 37, and an annular casing 39 comprising a cylindrical transparent quartz tube 32. The heating element chamber 4 is provided in the casing 39.
3 is formed. Further, a halogen lamp 41 as a ring-shaped heat source is provided in the heating element chamber 43, and an optical reflection mirror 42 is provided around the halogen lamp 41. The mold apparatus 10 is provided in the transparent quartz tube 32.

Therefore, when the halogen lamp 41 is turned on, the light of the halogen lamp 41, that is, infrared rays, is irradiated on the mold apparatus 10 through the transparent quartz tube 32 and is reflected by the optical reflection mirror 42. After the light is collected and condensed, the mold device 10 is irradiated through the transparent quartz tube 32. The optical reflection mirror 4
Reference numeral 2 has a shape that reflects the infrared rays of the halogen lamp 41 and mainly irradiates the central portion of the mold device 10 in the axial direction. As a result, the central portion in the axial direction of the mold apparatus 10 is heated intensively, and the preform 1 is heated.
5 is efficiently heated.

The transparent quartz tube 32 is
0 while maintaining the airtightness of the halogen lamp 41
In this case, the mold apparatus 10 is effectively heated by almost transmitting infrared rays in the above wavelength range. In addition, a first thermocouple th1 as a first temperature detector is disposed at a predetermined position of the mold device 10, for example, a central portion in the axial direction of the body mold 13, and the lower core 11 Is provided with a second thermocouple th2 as a second temperature detector, and a control device (not shown) controls the body temperature detected by the first thermocouple th1 and a lower temperature by the second thermocouple th2. The temperature of the mold apparatus 10 is controlled based on the core temperature detected for the mold core 11. In addition, a third thermocouple (not shown) can be provided on the upper core 12 as needed. In this case, for example, an average value of the temperature of the lower die core 11 and the temperature of the upper die core 12 detected by the third thermocouple is calculated, and the mold apparatus is calculated based on the average value and the body temperature. 1
0 temperature can be controlled.

The mold clamping device 50 has a lower end opposed to the body mold 13, and has a mold clamping rod 51 movably arranged in a vertical direction, and is attached to an upper end of the mold clamping rod 51. An annular mold clamping plate 52 is provided, and a plurality of pneumatic mold clamping cylinders 53 disposed between the upper plate 35 and the mold clamping plate 52. The mold clamping cylinder 53 includes a cylinder portion 53a fixed to the upper plate 35 and a rod portion 53b fixed to the mold clamping plate 52, and is driven by compressed air. Therefore, in each of the cylinder portions 53a, the compressed air source SU1 is connected to the head side air chamber 53c via the air flow path L1.
However, a servo valve 64 is connected to the rod-side air chamber 53d via the air flow path L2. And the servo valve 6
4 is connected to the compressed air source SU2 via the air flow path L3, and is connected to the atmosphere via the air flow path L4. The air flow path L2 is provided with a pressure detector Pr1 for detecting the pressure of the compressed air.

The pressurizing device 60 has a lower end opposed to the upper mold core 12 and is disposed in the mold clamping rod 51, and a pressurizing rod 61 movably arranged in a vertical direction.
A pressure plate 62 attached to the upper end of the pressure rod 61 and a plurality of pneumatic pressure cylinders 63 disposed between the mold clamping plate 52 and the pressure plate 62 are provided. The pressurizing cylinder 63 is provided with the mold clamping plate 5.
2 and a rod 63b fixed to the pressure plate 62, and are driven by compressed air. Therefore, each of the cylinder portions 6
In 3a, the compressed air source SU3 is connected to the head side air chamber 63c via the air flow path L5, and the servo valve 65 is connected to the rod side air chamber 63d via the air flow path L6. The servo valve 65 is connected to the compressed air source SU4 via the air flow path L7 and communicates with the atmosphere via the air flow path L8. The air flow path L6 is provided with a pressure detector Pr2 for detecting the pressure of the compressed air.

A first bellows 33 is disposed between the upper plate 35 and the mold clamping plate 52 so as to surround the mold clamping rod 51, and a first bellows 33 is provided between the mold clamping plate 52 and the pressure plate 62. Then, surrounding the pressure rod 61, the second
A bellows 34 is provided. Therefore, the molding chamber 20 can be sealed by the first bellows 33, the second bellows 34, and the pressure plate 62. In order to shut off the inside and outside of the molding chamber 20, a sealing device (not shown) is provided, and the inside of the molding chamber 20 is evacuated or an inert gas atmosphere is formed in the molding chamber 20. In addition, an atmosphere forming device (not shown) is provided.

By driving the mold clamping cylinder 53, the mold clamping plate 52 can be moved up and down while the inside and outside of the molding chamber 20 are shut off. Also,
By driving the pressurizing cylinder 63, the molding chamber 2
The pressure plate 62 can be moved up and down in a state where the inside and outside are shut off. Since the pressure rod 61 is fixed to the pressure plate 62, the pressure cylinder 6
3 is moved up and down together with the pressurizing plate 62 in accordance with the driving of 3.

When a constant pressure P _SU1 is generated by the compressed air source SU1, the pressure in the head side air chamber 53c is maintained at the pressure P _SU1 , and a constant pressure P _SU3 is generated by the compressed air source SU3. Then, the pressure in the head-side air chamber 63c is maintained at the pressure P _SU3 . On the contrary,
The cylinder pressure in the rod side air chamber 53d is controlled by the servo valve 64.
Is controlled is the P _M by the rod-side air chamber 63d
Cylinder pressure is controlled by a servo valve 65 and P
_{It is made P.}

Next, the heating device 40 will be described. FIG. 4 is a sectional view of a main part of the heating device according to the embodiment of the present invention, FIG. 5 is a plan view of the halogen lamp according to the embodiment of the present invention, and FIG. 6 shows an irradiation pattern of the halogen lamp according to the embodiment of the present invention. FIG. As shown in the figure, the heating device 40 includes a halogen lamp 41 disposed around the mold device 10 and the halogen lamp 4.
An annular optical reflecting mirror 42 is provided along 1 and surrounding the halogen lamp 41. Both ends of each halogen lamp 41 are connected to a power source (not shown) via a terminal 41a. The halogen lamp 41 is
The semicircular portions 81 and 82 are formed into a ring shape by joining them.

Then, as described above, the optical reflection mirror 42 reflects the infrared light of the halogen lamp 41 and irradiates the mold apparatus 10 with a predetermined irradiation pattern as shown in FIG. For this purpose, a reflection surface 42a is formed on the optical reflection mirror 42, and the reflection surface 42a is processed into a mirror surface and is plated with gold having a high reflectance. The irradiation pattern is set, for example, so as to approximate a distribution pattern of a normal probability distribution. The light intensity in the central portion is high, and the light intensity decreases as the distance from the central portion increases.

In this case, the heating efficiency of the preform 15 (FIG. 3) can be increased.
Can be increased, and the molding cycle can be shortened. Further, since a ceramic material can be used as a material of the mold apparatus 10, the mold apparatus 1
0 cost can be reduced. In addition, since the mold device 10 is mainly heated in the central portion in the axial direction, the temperature of the central portion in the axial direction of the mold device 10 can be sufficiently increased. Further, since it is possible to prevent the temperature of a portion other than the central portion in the axial direction of the mold device 10 from becoming excessively high, the accuracy of centering the lower mold core 11, the upper mold core 12, and the body mold 13 can be improved. Can be maintained.

Since the amount of heat input to the mold apparatus 10 can be set to a set value, the heating speed of the preform 15 can be increased. In the present embodiment, the halogen lamp 41 is formed in a ring shape by joining the semicircular portions 81 and 82, but a ring-shaped halogen lamp integrally formed may be used. it can. In addition, 3 halogen lamps 41
A ring can be formed by combining at least two arc-shaped portions.

Next, a control circuit of the glass forming machine having the above configuration will be described. FIG. 1 is a control circuit diagram of the glass forming machine according to the embodiment of the present invention, and FIG. 7 is a time chart showing the operation of the glass forming machine according to the embodiment of the present invention. In the figure, reference numeral 70 denotes a control device.
Reference numeral 0 denotes a body control unit 71 that controls the body temperature θ1 to calculate a power command value as a control output, and a core control unit 7 that controls the core temperature θ2 to calculate a power command value as a control output.
2. a signal switch 73 for switching between control of the trunk temperature θ1 and control of the core temperature θ2 by switching between a control output signal of the trunk control unit 71 and a control output signal of the core control unit 72; A subtractor 74 for subtracting the trunk temperature θ _S1 detected by the first thermocouple th1 from the target temperature θ _REF1 of the trunk temperature θ1 as a target value of 1 to calculate a deviation Δθ1, and a second target value Subtracter 7 for subtracting the core temperature θ _S2 detected by the second thermocouple th2 from the target temperature θ _REF2 of the core temperature θ2 as a function to calculate a deviation Δθ2.
5 is provided.

It should be noted that the body temperature θ1 and the core temperature θ2 are controlled.
Control is feedback control, and
The section 71 is based on the deviation Δθ1,_S1Is the target temperature
Degree θ _REF1Output the power command value so that
72 is the core temperature θ based on the deviation Δθ2._S2Is the target temperature
θ_REF2The power command value is output so that The body type system
Control unit 71, core control unit 72, and subtractors 74 and 75.
Therefore, it is possible to use a commercially available PID temperature controller.
it can.

The signal switch 73 is connected to a terminal 73.
a and 73c, and selectively connects between the terminals 73b and 73c, and comprises a switch SW for switching between a power command value output from the trunk type control unit 71 and a power command value output from the core control unit 72, The switch SW is connected to the control device 70
Is operated by control switching means (not shown).
Note that an electronic switch is used as the switch SW.

Then, the power command value W _S output from the control device 70 is sent to a power regulator 76, which converts the power command value W _S into a current i. Is sent to the halogen lamp 41. By the way, if only the body temperature θ _S1 is detected and only the body temperature θ1 is controlled based on the body temperature θ _S1 , the temperature of the preform 15 (FIG. 2) is set to the optimum target temperature for molding. And the reproducibility of the temperature of the preform 15 is low. Also,
Since it functions so as to prevent the occurrence of overshoot in the temperature of the preform 15, the time required for the temperature of the preform 15 to reach the target temperature becomes longer.

On the other hand, if only the core temperature θ _S2 is detected and only the core temperature θ ₂ is controlled based on the core temperature θ _S2 , when the core temperature θ _S2 reaches the target temperature θ _REF2 , In addition, the body temperature θ1 becomes significantly higher than the core temperature θ2, and the body 13 is excessively thermally expanded or thermally deformed, so that the durability of the mold apparatus 10 is reduced. Therefore,
The control switching means operates the signal switch 73 to switch the first
The control of the drum temperature θ1 is performed by placing the control point on the drum 13 in the process of step 2, and the second step is performed at a predetermined timing t1 when the switching condition set corresponding to the core temperature θ2 is satisfied. Starting, the control of the core temperature θ2 is performed by placing a control point on the lower mold core 11 in the second step. In this case, the timing t
As 1, the point at which the core temperature θ _S2 reaches the target temperature θ _REF3 as the third target value is selected. Note that the target temperature θ _REF3 is set lower than the target temperature θ _REF2 . Also,
If necessary, the control point in the second step is
Can also be placed.

And, depending on the material of the body mold 13, the body mold 13
Heat resistance, coefficient of thermal expansion, etc.
θ_REF1Is set in consideration of the material of the body mold 13. In addition,
Target temperature θ_REF2Is the molding temperature of the glass used as the material for the molded product
It is set in consideration of. In addition, the press
When heating the reform 15, heat is first applied to the barrel mold 13
To the upper core 12 and the lower core 11
Is transmitted, the body temperature θ1 is always higher than the core temperature θ2.
High, and the rise of the shell mold temperature θ1 is higher than the core temperature θ2.
Faster than rising. Therefore, the target temperature θ_REF1Eyes
Target temperature θ _REF2Set higher.

The larger the temperature difference between the shell 13 and the lower core 11 and the upper core 12, the greater the amount of heat transferred from the shell 13 to the lower core 11 and the upper core 12. While the body temperature θ1 is being controlled, the core temperature θ2 rises faster as the body temperature θ1 increases. Further, since the target temperature θ _REF1 is set in consideration of the material of the shell 13, the target temperature θ _REF1 is set to the highest value allowed for the material of the shell 13, and thus the core temperature θ 2
Can be started at the highest heating rate.

In this embodiment, the switching condition is that the core temperature θ _S2 has reached the target temperature θ _REF3 . However, the core temperature θ _S2 is differentiated by a differentiating means (not shown) in the body type control unit 71. The switching condition can be that the differential value has become lower than the threshold value. The switching condition may be that a set time has elapsed since the heating of the mold apparatus 10 was started.

As described above, the body temperature θ1 is controlled in the first step, and the core temperature θ2 is controlled in the second step.
Since the control of the is to be carried out, the power command value W _S along with the second step is started is small.
Therefore, when the core temperature θ _S2 reaches the target temperature θ _REF3 , it is possible to prevent the trunk mold temperature θ1 from becoming significantly higher than the core temperature θ2, so that the trunk mold 13 may be excessively thermally expanded. In addition, heat deformation does not occur, and the durability of the mold apparatus 10 can be improved.

Further, with the start of the second step, the core temperature θ2 of the lower mold core 11 that is in contact with the preform 15 to be actually molded is controlled.
It becomes easy to set the temperature of the preform 15 to the optimal target temperature for molding, and the reproducibility of the temperature of the preform 15 can be improved. Then, the overshoot does not occur in the temperature of the preform 15, and the time required for the temperature of the preform 15 to reach the target temperature can be shortened.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0037]

As described above in detail, according to the present invention, in the glass forming machine, the first core and the first core are provided.
A second core movably disposed in opposition to the first core, a barrel die for guiding the second core, a heating device for heating the first and second cores, A pressure device for applying pressure to the core, a first temperature detector for detecting the temperature of the body mold, and a second temperature for detecting the temperature of at least one of the first and second cores It has a detector and a control device that controls the temperature of the die in the first step and controls the temperature of the core in the second step.

In this case, the temperature of the body mold is controlled in the first step and the temperature of the core is controlled in the second step, so that the second step is started. Accordingly, the power command value is reduced. Therefore, when the temperature of the core reaches the second target temperature, it is possible to prevent the temperature of the body mold from becoming significantly higher than the temperature of the core, so that the body mold is excessively thermally expanded, Thermal deformation does not occur, and the durability of the mold device can be improved.

Further, as the second step is started, the first and second parts which come into contact with the object to be actually molded are formed.
Since the control of the temperature of the second core is performed, it is easy to set the temperature of the molded object to the target temperature optimum for molding, and the reproducibility of the temperature of the molded object can be improved. Since the overshoot does not occur in the temperature of the molded object, the time required for the temperature of the molded object to reach the target temperature can be shortened.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a glass forming machine according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a glass forming machine according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram of a mold device according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part of the heating device according to the embodiment of the present invention.

FIG. 5 is a plan view of the halogen lamp according to the embodiment of the present invention.

FIG. 6 is a diagram showing an irradiation pattern of a halogen lamp according to the embodiment of the present invention.

FIG. 7 is a time chart showing an operation of the glass forming machine in the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 11 lower die core 12 upper die core 13 trunk die 40 heating device 50 die clamping device 60 pressing device 70 control device th1, th2 first and second thermocouples θ1 trunk temperature θ2 core temperature θ _REF1 , θ _REF2 target temperature

Claims (3)

[Claims] (A) a first core; and (b) a second core movably disposed to face the first core.
(C) a barrel die for guiding the second core, (d) a heating device for heating the first and second cores, and (e) a second heating device for heating the first and second cores.
(F) a first temperature detector for detecting the temperature of the body mold; and (g) a first temperature detector for detecting a temperature of the body mold.
A second temperature detector for detecting at least one temperature of the second core; and (h) controlling the temperature of the shell mold in the first step, and controlling the temperature of the core in the second step. A glass forming machine comprising: (A) controlling the temperature of the body die so that the temperature of the body die becomes a first target value; and (b) controlling the temperature of the core, wherein the temperature of the core is controlled to the first target value. 2. The glass forming machine according to claim 1, wherein the first target value is set to be higher than a second target value. 3. The glass forming machine according to claim 1, wherein the second step is started when a switching condition set according to the temperature of the core is satisfied.