JPH082930A - Forming mold and heating of forming mold - Google Patents

Abstract

PURPOSE:To enable the control of temperature within + or - several deg.C by the heating for several tens seconds or shorter by heating a forming mold from inside in place of the conventional atmospheric heating using a heating furnace. CONSTITUTION:This forming mold 1 has a bottom-closed cylindrical form having a reflection member 2 having a roughness of <=0.5mum on the inner bottom surface and a roughened face 3 having a surface roughness of 0.7-2mum on the inner circumferential surface. Electromagnetic wave is radiated on the reflection member 2 and the reflected wave is absorbed in the roughened surface 3 to heat the forming mold 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for pressing a heat-softened glass material to mold a desired optical element, and more particularly to a mold suitable for producing glass cells and a method for heating the mold.

[0002]

2. Description of the Related Art In analyzing the components of various samples such as blood and reagents, a sample is put in a glass cell and light is applied to the sample for analysis and measurement. As a method of manufacturing such a cell, for example, a vacuum processing method as disclosed in JP-A-1-38055 is known.

In the publication, an inner mold is inserted into a glass bottomed tube, and a gap between the bottomed tube and the inner mold is sucked by a vacuum pump and slowly lowered into the electric furnace. The bottomed tube is gradually softened from the bottom toward the opening, and is molded into a shape along the inner mold by suction negative pressure.

[0004]

However, in the above-mentioned prior art, since the bottomed tube has to be moved slowly from the bottom to the opening in the heated portion, the cycle time is long and the manufacturing efficiency is low. There was a problem.

As another method for shortening the cycle time, the bottomed tube and the molding die are individually temperature-controlled, and pressure molding is performed using an outer die and an inner die having a lower temperature than the bottomed tube. However, if the temperature of the inner mold is raised above the temperature in the heating furnace, the temperature distribution in the furnace is disturbed and it becomes difficult to control the temperature. In this case, a difference of ± 3 ° C or more from the set temperature causes seizure, cracking, or sink mark. Further, in the heating of the outer circumference atmosphere using the heating furnace, there is also a problem that it generally takes a long time to stabilize the temperature of the atmosphere inside the furnace and the mold itself.

The present invention has been made in view of the above problems, and by heating the forming die from the inside instead of the conventional atmosphere heating using a heating furnace, the heating time is within several tens of seconds at several degrees Celsius. It is an object of the present invention to provide a mold capable of controlling the temperature within (preferably ± 3 ° C.) and a method for heating the mold.

[0007]

In order to achieve the above object, a molding die of the present invention according to claim 1 is a bottomed tube-shaped molding die, and the inner bottom surface of the molding die has surface roughness. A reflecting member having a thickness of 0.5 μm or less is provided, and the inner peripheral side surface of the mold has a rough surface portion having a surface roughness of 0.7 μm or more and 2 μm or less.

In this case, as described in claim 2, it is preferable that the reflecting member is coated with metal and the rough surface portion is coated with ceramic or cermet.

Further, as described in claim 3, the shape of the reflecting member may be any one of a quadrangular pyramid, a convex curved surface and a concave curved surface.

When heating such a mold, as described in claim 4, the reflecting member is irradiated with an electromagnetic wave having a wavelength of 0.75 μm or more and 25 μm or less, and the reflected wave is applied to the rough surface portion. To absorb.

In this case, as described in claim 5, the temperature of the molding die is measured by a temperature measuring means such as a thermocouple or a radiation thermometer, and when the measured temperature is lower than a set temperature, the irradiation output of the electromagnetic wave. When the measured temperature is higher than the set temperature, the temperature is adjusted by blowing a cooling gas to the mold to cool it.

[0012]

In the molding die and the method for heating the molding die of the present invention having the above-mentioned constitution, an electromagnetic wave of 0.75 to 25 μm, for example, a heat ray or a laser beam of a high pressure mercury lamp, a Nernst globe, a glober, a tungsten lamp or the like is injected into the molding die. The light is reflected by the reflection member on the bottom and absorbed by the rough surface portion on the inner peripheral side surface of the molding die to heat the molding die.

Here, if the wavelength of the electromagnetic wave is less than 0.75 μm, the inner surface of the molding die may be destroyed, and adverse effects may occur.
If it exceeds μm, the efficiency of heat absorption becomes low and the purpose of heating cannot be achieved.

[0014]

Embodiments of the mold and the method for heating the mold according to the present invention will be described below with reference to the accompanying drawings. In addition,
In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

(Embodiment 1) FIG. 1 is a perspective view showing a molding die of Embodiment 1. In the figure, the molding die 1 is a bottomed tube with a quadrangular prism shape and a hollow inside. The outer dimensions are 30 x 30 mm on the bottom, 40 mm in height, and the inner cavity is 15 x.
It has a depth of 15 mm and a depth of 35 mm. The molding die 1 is made of tungsten carbide, and the outer peripheral side surface and the outer bottom surface are mirror-finished to have a surface roughness Rmax of 0.5 μm or less, and then PV.
The nitride is coated by means such as D or CVD.

A reflecting member 2 is provided on the inner bottom surface of the molding die 1. This has a surface roughness of 0.5 μm on the inner bottom surface of the molding die 1.
After being mirror-finished below, it is mirror-finished by coating a metal such as gold, silver, platinum, or aluminum. And
The reflecting member 2 is formed into a convex quadrangular pyramid, and its angle is set so that the electromagnetic wave incident from the opening of the molding die 1 is reflected toward the inner peripheral side surface 3. The reflecting member 2 may be formed in a convex or concave hemispherical shape.

The inner peripheral side surface of the molding die 1 is a rough surface portion 3. Specifically, after grinding to a surface roughness Rmax of 1.0 μm or more, black silicon carbide is coated to increase the heat absorption rate. As a material other than silicon carbide, a carbide having excellent heat resistance such as titanium carbide or chromium carbide or chromium oxide, or a cermet such as sialon may be used.

A method of using the molding die thus constructed will be described with reference to FIG. In the figure, reference numeral 5 is a halogen lamp that emits infrared rays 6 which are electromagnetic waves, and is connected to a control device 8 via a connection cord 7 and controlled in a variable output manner. The thermocouple 9 is a temperature measuring means for detecting the temperature of the mold and is connected to the control device 8. Reference numeral 4 is a reflecting mirror that focuses the infrared rays 6 from the halogen lamp toward the reflecting member 2. The infrared rays 6 reach the rough surface portion 3 after being reflected by the reflecting member 2. Then, it is absorbed by the rough surface portion 3 which is black and has a rough surface, and the molding die 1 is heated by this energy. The cooling device 10 is a cooling device arranged so as to surround the outer peripheral side surface of the molding die 1, and ejects a non-oxidizing gas such as nitrogen, argon, or helium. The controller 8 detects the temperature of the mold 1 by the thermocouple 9, increases the irradiation output of the halogen lamp 5 when the measured temperature is lower than the set temperature, and increases the irradiation output of the halogen lamp 5 when the measured temperature is higher than the set temperature. A cooling gas is blown onto the to cool it.

Now, the operation of the control device 8 will be further described. The control device 8 performs optimum control by arithmetic processing so that the time required for heating to the set temperature is the shortest. Specifically, the output of the halogen lamp 5 is changed according to the size of the difference between the set temperature and the temperature detected by the thermocouple 9. Immediately after the start of heating with a large temperature difference, a large output is output immediately. On the other hand, while heating, when the temperature approaches the set temperature, the output is reduced to prevent a large overshoot. Furthermore, by spraying the cooling gas, the overshoot is positively suppressed and the time required to reach the set temperature is shortened.

In controlling the temperature of the molding die, generally, a temperature within the range of glass transition point minus 150 ° C. to transition point plus 20 ° C. is selected, which is considered not to cause glass seizure and cracking. For example, transition temperature 560 ℃
When the borosilicate glass of No. 3 was used, it was optimum to set the mold at 530 ° C. With the above configuration, it was possible to reduce the temperature error within ± 3 ° C with respect to the set temperature of 530 ° C. Moreover, the time required for this is only several tens of seconds, and it takes at least 1 minute to heat the outer peripheral atmosphere by the heating furnace, while the heating time can be greatly shortened.

(Embodiment 2) Next, another example of the present invention will be described with reference to FIG.
It differs from the above embodiment in that the inner bottom surface of itself is not mirror-finished, but a separate reflecting member is attached.

The outer shape of the molding die 1 is 5 × 5 mm on the outside,
The height is 40 mm, the inner cavity is 2 × 2 mm, and the depth is 35 mm. As described above, since the inner side is small and it is difficult to process the inner bottom surface, a separate reflecting member 11 is attached. The reflecting member 11 is made of tungsten carbide, and the upper surface of the convex curved surface is mirror-finished to have a surface roughness Rmax of 0.5 μm or less and then coated with platinum.

In this embodiment, instead of the halogen lamp,
Laser light such as carbon dioxide laser or YAG laser 12
Was used. The laser light is emitted from the opening of the molding die 1 toward the inner bottom surface, is reflected by the reflecting member 11, and is absorbed by the rough surface portion 3 on the inner peripheral side surface. The output of the laser oscillator is controlled by the controller as in the first embodiment.

By thus forming the reflecting member separately, it can be applied to a molding die having a small inner diameter.

The present invention is not limited to the above embodiment, and various modifications can be made especially to the shape of the reflecting member.

(1) In FIG. 4 (a), the reflecting member 11 is made of a quartz plate, and the minute quadrangular pyramids are arranged vertically and horizontally. As a result, the incident electromagnetic wave is diffusely reflected, so that the entire inner peripheral side surface is uniformly heated. Further, the same effect can be obtained in an example in which minute convex curved surfaces as shown in FIG. 9B and minute concave curved surfaces as shown in FIG.

(2) The reflecting member 11 may be flat. However, in this case, it is necessary to provide a light source at a position eccentric from the center axis of the molding die so that the reflected electromagnetic waves reach each surface of the inner peripheral side surface and allow the electromagnetic waves to enter obliquely. In this case, four light sources are provided, or the light sources are arranged on the central axis of the molding die and reflecting mirrors are provided at four places around the molding die, but the configuration is slightly complicated. It can be made uniform.

[0028]

As described above, according to the molding die and the method for heating the molding die of the present invention, the molding die is heated from the inside unlike the conventional atmosphere heating using the heating furnace. , To a temperature within ± a few degrees of the set temperature,
It can be heated in a heating time of only several tens of seconds.

[Brief description of drawings]

FIG. 1 is a perspective view showing a molding die according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a method for heating a molding die according to Example 1 of the present invention.

FIG. 3 is a sectional view showing a method for heating a molding die according to Example 2 of the present invention.

FIG. 4 is a perspective view showing a modified example of the reflection member of the present invention.

[Explanation of Codes] 1 Mold 2 Reflective member 3 Rough surface part 4 Reflector 5 Halogen lamp 6 Infrared (electromagnetic wave) 7 Connection code 8 Control device 9 Thermocouple 10 Cooling device 11 Reflecting member 12 Laser light

Claims (5)

[Claims] 1. A bottomed tube-shaped molding die, wherein a reflection member having a surface roughness of 0.5 μm or less is provided on an inner bottom surface of the molding die, and an inner peripheral side surface of the molding die has a surface roughness. 0.7 μm
A molding die having a rough surface portion of 2 μm or less. 2. The mold according to claim 1, wherein the reflecting member is coated with a metal, and the rough surface portion is coated with a ceramic or a cermet. 3. The mold according to claim 1, wherein the shape of the reflecting member is any one of a quadrangular pyramid, a convex curved surface, and a concave curved surface. 4. The method for heating a molding die according to claim 1, wherein the reflecting member is irradiated with an electromagnetic wave having a wavelength of 0.75 μm or more and 25 μm or less, and the reflected wave is absorbed by the rough surface portion. A method for heating a molding die characterized. 5. The temperature of the mold is measured by a temperature measuring means such as a thermocouple, and when the measured temperature is lower than the set temperature, the irradiation output of the electromagnetic wave is increased, and when the measured temperature is higher than the set temperature, the molding is performed. The method for heating a molding die according to claim 4, wherein the mold is cooled by spraying a cooling gas.