JPH0437620A - Casting device for glass ceramics and its casting method - Google Patents

Abstract

PURPOSE:To obtain a uniform crystal state of cast product, to prevent welding between the casting material and the casting mold, and to obtain high-quality cast products by completely melting the casting material such as glass ceramics at high temp., and then decreasing the temp. to the casting temp. CONSTITUTION:The casting material such as glass ceramics contained in a platinum crucible is heated to a temp. higher than the casting temp. and maintained at this temp. for a certain period. The casting material is completely molten so as to obtain a uniform crystal state of the cast product. Then the high temp. of the casting material is decreased to the casting temp., and the material is poured in a casting mold and cast by centrifugal rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a high-frequency centrifugal casting apparatus and a casting method thereof using glass ceramic or the like as a casting material.

(Prior art) In general, metal materials such as gold and platinum are stored in a crucible placed on the axis of a heating coil and melted using induced current, and the molten metal is then melted using centrifugal force. As a literature on high frequency centrifugal casting equipment that pours metal into a mold and casts,
For example, there is Japanese Utility Model Publication No. 56-26728.

The technique disclosed in this publication is a method of heating a casting material to a predetermined temperature, maintaining that temperature for a certain period of time, and then performing centrifugal casting.

The apparatus according to the above method includes a crucible and a mold material mounted on a support rod on which the apparatus is rotated so as to be balanced with a balance weight, a high-frequency heating circuit for melting the metal material in the crucible with a heating coil, and a high-frequency heating circuit for melting the metal material in the crucible using a heating coil. The temperature control section includes a detection means for detecting metal temperature, and a timer circuit for controlling the heating coil and the high-frequency heating circuit on and off for a certain period of time according to the detected value.

Therefore, with the above structure, the molten metal after melting is maintained at a predetermined temperature for a certain period of time, which prevents overheating of the molten metal and provides a sufficiently stirred, high-quality casting material.

[Problem to be solved by the invention]

In the technique disclosed in the above-mentioned publication, if the predetermined temperature is set low, the particles of the casting material may not be sufficiently melted, resulting in uneven crystallization of the resulting casting, or the crucible may become unstable during repeated castings. There was a problem in that the material stuck to the spout and the pouring material could not be poured smoothly, and if the predetermined temperature was set high, the casting material reacted with the mold material and fused.

The present invention was made in view of the above-mentioned problems.The casting material is completely melted, the crystalline state of the obtained casting is made uniform, and as the casting is repeated, the material is poured into the spout of the crucible. The crucible is heated to a temperature higher than the casting temperature at which the material will not stick and held for a certain period of time, and then lowered from the high temperature state to the specified casting temperature to prevent the casting material from reacting with the mold and fusing. Detects the output value of the thermocouple connected to the high frequency heating circuit for a certain period of time.
It is an object of the present invention to provide an apparatus for casting glass ceramics, etc., and a method for casting the same, using a temperature control section that performs DIII.

[Means to solve the problem]

The present invention provides a crucible unit equipped with a platinum-based crucible connected to a platinum-based thermocouple that houses and heats a casting material such as glass ceramic, and a high-frequency unit equipped with a heating coil that heats the casting material in the platinum-based crucible. a heating means, a driving means for transferring the melt to the heating coil provided in the crucible unit and pouring the heated and melted casting material into a mold, and casting the casting material poured into the mold by centrifugal rotation. This is a casting apparatus for glass ceramics, etc., which is equipped with a centrifugal drive means, and a temperature control unit that controls temperature detection, temperature adjustment, and setting temperature switching of the casting material in the platinum-based crucible.

[Function] The casting method (action) using the above-mentioned structure consists of a heating process in which the casting material in the platinum crucible is heated to a temperature higher than the predetermined casting temperature, and a high-temperature holding process in which this high temperature is maintained for a predetermined time. A glass-ceramic glass ceramic comprising: a lowering temperature step in which the temperature is lowered from this high temperature to a predetermined casting temperature; and a centrifugal step in which the casting material is poured into a mold at the above casting temperature and cast by centrifugal rotation.

This is a casting method such as casting.

(Example〕 The present invention will be explained based on examples.

In the drawings, common configurations and common mechanisms of each embodiment will be explained in the first embodiment and will be omitted in subsequent embodiments.

(First Embodiment) FIG. 1 is a schematic diagram showing an outline of a glass-ceramink casting apparatus according to the present invention.

FIG. 2 is a block diagram showing the configuration of the temperature control section shown in FIG. 1.

FIG. 3 is a graph diagram showing a temperature control profile in the first embodiment of the method for casting glass-ceramics, etc. according to the present invention.

Reference numeral 1 shown in FIG. 1 is a platinum-based crucible to which a platinum-based thermocouple 7 is connected for heating and melting a casting material such as glass ceramic. This platinum-based crucible 1 has a crucible unit 3 composed of a cover and a heat insulating member, and this crucible unit 3 is moved in and out of a heating coil 2 provided in a high frequency heating circuit 6 that heats and melts the casting material. and a crucible unit 7) drive unit 4 that performs an operation of pouring heated and melted casting material into the mold 11. A centrifugal drive unit 5 is provided which casts by centrifugal rotation a mold 11 storing the casting material heated by the heating coil 2 and a balancer 12 mounted in a scale shape to balance the mold 11.

In addition, the temperature of the casting material in the platinum crucible 1 is detected by the output of the platinum thermocouple 7, and the temperature is divided into two stages by PIDI.
! A temperature control unit 10 is configured, which includes a temperature regulator 8 that can control the temperature, and a switching circuit 9 that switches the set temperature.

The manufacturing process of this embodiment having the above configuration will be explained.

First, a casting material such as glass ceramic is placed in a platinum-based crucible 1. Subsequently, the platinum-based crucible 1 containing the casting material is inserted into the heating coil 2 provided in the high-frequency heating circuit 6 by the drive of the crucible unit drive section 4, and is heated to a predetermined high temperature. The high temperature in this case is, for example, 1450'C (A), which is higher than the casting temperature, as shown in FIG. This high temperature is maintained for a predetermined time (for example, 1 minute) to completely melt the casting material. The cast material in the platinum-based crucible 1 that has been kept at the high temperature for the above-mentioned time is
The temperature is lowered to the casting temperature to prevent the casting material and the platinum-based crucible 1 from fusing. The casting temperature in this case is the third
For example, as shown in the figure, it is lowered to 1250'C (B). The casting material in the platinum-based crucible 1, which has been lowered to a predetermined casting temperature, is poured into the mold 11 by driving the crucible unit driving section 4.

The mold 11 into which the casting material has been poured is mounted on the centrifugal drive unit 5 so as to be balanced with the balancer 12, and cast by centrifugal rotation.

In the above, the high temperature heating, casting temperature, and high temperature holding time are controlled by the temperature control section 10.

Further, the temperature setting and holding time setting described above are switched or changed to a desired temperature and time depending on the material to be cast.

According to this embodiment using the apparatus and manufacturing method having the above configuration, the casting material can be completely heated and melted, and the casting material and the platinum crucible 1 do not fuse, so high-frequency centrifugal casting with high quality can be performed. .

(Second Embodiment) The configuration of the casting apparatus of this embodiment is the same as that of the first embodiment, so a description thereof will be omitted. Therefore, only the casting method will be described.

FIG. 4 is a graph diagram showing a temperature control profile in a second embodiment of the method for casting glass-ceramics, etc. according to the present invention.

First, a casting material such as glass ceramic is placed in a platinum-based crucible l. Next, platinum crucible 1 containing casting materials
The high frequency heating circuit 6 is driven by the crucible unit drive unit 4.
The device is inserted into a heating coil 2 installed in a heating coil 2 and heated to a predetermined high temperature. The high temperature in this case means heating to a temperature higher than the preset casting temperature, for example, 1450° C. (A), as shown in the fourth section. The cast member heated to this high temperature is held for 1 minute to completely melt it.

After the high-temperature holding time, the casting material in the platinum-based crucible 1 is lowered to the casting temperature as shown in FIG. 4 in order to prevent the casting material and the platinum-based crucible 1 from fusing. The casting temperature in this case is lowered to, for example, 1250°C (B). Furthermore, the casting material in the platinum crucible 1 that has been lowered to this casting temperature is held at the same temperature for a preset one minute.

The casting material in the platinum-based crucible 1 after the above-mentioned temperature period is poured into the mold 11 by driving the crucible unit driving section 4 .

The mold 11 into which the casting material has been poured is mounted on the centrifugal drive unit 5 so as to be balanced with the balancer 12, and centrifugally rotated for casting.

In the above case as well, the high temperature heating, the casting temperature, the high temperature holding time, and the casting temperature holding time are controlled by the temperature control section 10, as in the first embodiment. Furthermore, the temperature settings and temperature holding time settings can be varied to desired temperatures and times depending on the casting material to be cast.

According to this embodiment using the apparatus and manufacturing method having the above configuration,
High-frequency centrifugal casting is possible under good casting conditions and stable against source fluctuations and disturbances.

〔Effect of the invention〕

According to the present invention, with the above structure and method, the casting material is sufficiently melted at high temperature, so that the crystal state becomes uniform, and furthermore, when pouring from the crucible into the mold, the material does not solidify at the pouring spout. In addition, by providing a step of heating to a high temperature and holding it for a certain period of time, the casting material is completely melted, resulting in high-quality casting. Further, by lowering the temperature from the high temperature state to the casting temperature, it is possible to prevent the casting material and the crucible from fusing.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an overview of a casting apparatus for glass ceramics, etc., according to the present invention. FIG. 2 is a block diagram showing the configuration of the temperature control section shown in FIG. 1. FIG. 3 is a graph diagram showing a temperature control profile in the first embodiment of the method for casting glass-ceramics, etc. according to the present invention. FIG. 4 is a graph diagram showing a temperature control profile in a second embodiment of the method for casting glass-ceramics, etc. according to the present invention. FIG. 5 is a graph diagram showing a temperature control profile in a conventional high-frequency centrifugal device. 2... Heating coil 3... Crucible unit 4... Crucible unit drive section 5... Centrifugal drive section 6... High frequency heating circuit 7... Platinum thermocouple 8... Temperature controller 9 ... Set temperature switching circuit 10 ... Temperature control section 11 ... Mold 12 ... Balancer

Claims (2)

[Claims] (1) A crucible unit equipped with a platinum-based crucible connected to a platinum-based thermocouple that houses and heats a casting material such as glass ceramic, and a high-frequency heating system equipped with a heating coil that heats the casting material inside the platinum-based crucible. means, a driving means provided in the crucible unit for transferring the heated and melted casting material to the heating coil and pouring the heated and melted casting material into the mold, and casting the casting material poured into the mold by centrifugal rotation. 1. A casting apparatus for glass-ceramics, etc., comprising a centrifugal drive means, a temperature control unit that detects the temperature of the casting material in the platinum-based crucible, and controls temperature adjustment, setting temperature switching, etc. (2) A heating process in which the casting material in the platinum-based crucible is heated to a temperature higher than the predetermined casting temperature, a high-temperature holding process in which this high temperature is maintained for a predetermined time, and a descending process in which the high temperature is lowered to the predetermined casting temperature. A method for casting glass ceramics, etc., comprising a temperature step and a centrifugal casting step in which a casting material is poured into a mold at the above-mentioned casting temperature and cast by centrifugal rotation.