JPH0376643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for press molding plastic materials such as ceramics.

BACKGROUND ART Conventionally, pressure molding methods, injection molding methods, and the like are known for molding plastic materials. All of these methods are shaped by utilizing the plasticity of a powder layer or fluid system, and shape-retained by utilizing the yield value. However, in the case of automatic dry press molding, there are problems such as insufficient density or dimensions of the molded product,
Problems such as mold wear, occurrence of cracks, and uneven density were likely to occur. In addition, in injection molding, molten plastic material is press-fitted into a closed mold cavity, so the orientation due to the flow of the plastic material is noticeable, causing residual strain in the injection molded product. In molding, it is not possible to press with uniform pressure within the mold, so the molded product has different shrinkage rates in different parts and is easily deformed. On the other hand, in press molding, the plastic material can flow uniformly into the mold cavity by clamping the mold, so there is almost no residual strain and no deformation occurs in the molded product.

Problems to be Solved by the Invention However, in press molding, it is difficult to supply plastic materials, and high-temperature melting materials such as ceramics need to be supplied to the mold in a short time. Ta.

It is also known that molding is performed using an outer mold and an inner mold such as a piston/cylinder, as shown in Japanese Patent Publication No. 16-759, but it is not attached to the bed or slide of a press molding machine, and even if Even if it is mounted on a bed or slide, it is not easy to replace the mold and it is difficult to transport the molded product.

Means for Solving the Problems The present invention has been made in view of the above-mentioned points.A lower mold is attached to the bed side, an upper mold is attached to a slide facing this bed, and the slide is connected to a pressure cylinder. In a press molding device that can press freely up and down, a material supply nozzle is disposed in the upper mold or the lower mold, and an injection plunger of a predetermined capacity is connected to this material supply nozzle,
The pressurized cylinder is operated to bring the upper and lower molds close to closing, and a predetermined amount of molten material is injected from the injection plunger through the material supply nozzle in the upper or lower mold. A plastic material such as ceramics is supplied into a mold formed by the upper mold and a lower mold, and the plastic material such as ceramics is flow-filled into a predetermined cavity of the mold and press-molded. An object of the present invention is to provide a method for press molding plastic materials such as ceramics.

Example Hereinafter, the present invention will be explained based on examples.

FIG. 1 and the following are one embodiment of the present invention. The press molding device 1 is composed of a hydraulic press with a predetermined output and stroke, and the required pressure cylinders 3 are arranged on the upper frame 2 at the upper part, and the slide 4 can be moved up and down to the bed 5 side at the lower part. . As shown in Fig. 1, the upper mold 7 of the mold 6 is attached to the lower surface of the slide 4, and the lower mold 9 of the mold 6 is attached to the bed 5 via the bolster 8. There is. In the upper mold 7,
A material supply nozzle 11 is provided inside so that a plastic material 10 of ceramics or new ceramics can be supplied onto the lower mold 9, and a material supply passage 13 is communicated with this nozzle 11 via a heat insulating material 12. As shown in Figure 2, an injection plunger 1 that also serves as a metering device is connected to a flexible connecting pipe 14 that is appropriately kept warm by a heater or the like (not shown), and a shut-off valve 15.
6, and the plastic material 10 is melted to a predetermined temperature using a heating melting device (not shown) as in injection molding.
can be freely extruded and fed into the mold 6. In addition, 4 in the longitudinal direction of the bed 5 of the press molding device 1
At the corner, as shown in FIG. 1, a balance support device 17 such as a hydraulic servo cylinder is disposed to balance and support the descended slide 4 so that press forming can be performed. As shown in the figure, the balance support device 17 has a short stroke within the range required for pressure molding the plastic material 10, and its supporting force is approximately 1/2 to 5 times that of the pressure cylinder 3. 1
It is considered to be of a certain extent. On the side thereof, a position detector 18 such as a linear scale is installed, and a hydraulic servo valve 19 is installed.
The detection amount detected by the position detector 18 is fed back to perform synchronized control of the support position and descending speed of the support rod 20, and the descending slide 4 is adjusted to 5/100.
It is supported with a balance accuracy of within mm.
The plastic material 10 is pressed uniformly so that it can be uniformly fluidized and filled into a predetermined cavity 21 of the mold 6. In addition, as shown in FIG. 3, each equilibrium support device 17 is provided with a fluid/pressure conversion pressure detector 22 (which can be a load cell if necessary) for detecting the supporting force. The pressure is converted into a digital quantity by an A-D converter 23, summed by a calculator 24, and compared with a reference setting force of a reference support force setting device 25 by a comparison calculator 26. If the supporting force becomes larger than the reference setting force, the discharge flow rate of the servo pump 28 of the hydraulic device 27 is controlled to be reduced so as to slow down the descending speed of the slide 4, so that the supporting force becomes smaller than the reference setting force. For example, conversely, the flow rate of the servo pump 28 is increased so as to increase the descending speed of the slide 4, and the balance support device 17 is pressed with excessive pressure against the deformation resistance of the plastic material 10. The pressure is applied appropriately without moving away from the slide 4, so that it follows the slide 4 without leaving it. 29
is a heat insulating cover for protecting the balance support device 17 from the high temperature of the mold section, and can also be cooled by flowing air through an air hose (not shown) if necessary. 30 is a relief valve for avoiding excessive pressure. In addition,
Although not shown, the mold 6 has a known structure necessary for press molding of plastic materials, such as a heater installed to adjust the temperature.

Function When press-molding the ceramic plastic material 10, the speed, position, and pressure settings of the pressure cylinder 3 and the balance support device 17, as well as the mold 6
Necessary items such as temperature setting values are preset in a program, and a reference setting force for supporting force is set in the reference supporting force setting device 25. Then, the device is operated to lower the slide 4 as shown in FIG. It descends to a near state. And shut off valve 15
The mold is opened and the injection plunger 16 is operated to extrude and supply the plastic material 10 melted at a predetermined temperature from the material supply nozzle 11 of the upper mold 7 onto the lower mold 9 as shown in Fig. 2. It is. Lower mold 9
The plastic material 1 is placed in the upper mold 7 before the mold is closed.
0 is finished, and the upper mold 7 is moved through the slide 4.
is pressed against the lower mold 9 to flow-fill the plastic material 10 into a predetermined cavity 21 of the mold 6 and press-form it. In this way, the plastic material in a high temperature state can be supplied from inside the mold to the mold in a state close to the mold closing time, so the mold closing time can be shortened and the temperature drop of the plastic material can be prevented as much as possible. This reduces the deformation resistance of the plastic material and allows for smooth fluid filling into molds. Especially in the case of ceramics,
Because the melting temperature is high, over 1000°C, the temperature drops rapidly in a short period of time, and the effect of shortening the mold closing time is significant. The plastic material 10 is supplied by supplying the upper mold 7 to the lower mold 9 in number.
This may be done by temporarily stopping the upper mold 7 at a distance of about 10-odd centimeters, or may be carried out by continuously lowering the upper mold 7 without stopping.

Then, due to the deformation resistance of the plastic material 10, the pressing force of the balance support device 17 of the slide 4 is reduced,
The supporting force of the balance support device 17 is determined by the reference supporting force setting device 2.
When the force becomes smaller than the reference setting force set in step 5, the discharge flow rate of the servo pump 28 is increased to increase the descending speed of the slide 4 according to the control block diagram in FIG. 3, and vice versa. Slide 4
The descending speed of the slide 4 is slowed down, and the slide 4 is always pressed against and follows the support rod 20 of the balance support device 17. Therefore, it is possible to prevent an excessive load from being applied to the balance support device, and the slide can be lowered in a precisely balanced state, resulting in a product with uniform wall thickness and no uneven thickness. In addition, even if the plastic material is supplied while the mold is closed and the plastic material contacts the upper mold asymmetrically,
This prevents the upper mold from tilting and accurately maintains the balanced state of the slide. Furthermore, even if the plastic material has high deformation resistance, the supporting force is detected as described above and the pressing force of the pressurizing cylinder is adjusted so that the slide does not move away from the balance support device and follows it. Therefore, the plastic material can be fluidly filled into the cavity uniformly.

In this way, the plastic material 10 is hardened under pressure within the mold 6, the mold 6 is opened, and the molded material is carried out.
Press molding is repeated.

In the above embodiments, ceramics have been described as the plastic material, but the invention can also be applied to other similar plastic fluid materials such as amorphous.

In addition, in the above embodiment, the plastic material is supplied from the upper mold, but it can also be supplied from the lower mold, and instead of controlling the speed of the slide against the deformation resistance of the material, balance support is used. It is also possible to adjust the pressing force by controlling the speed of the device.

Effects of the Invention As described above, according to the present invention, the lower mold and the upper mold can be relatively easily installed and removed from the press molding apparatus, and the molds can be replaced. For example, press-molded products can be easily transported. By operating the injection plunger, the plastic material can be supplied into the mold through a material supply nozzle installed inside the mold. Therefore, it is possible to press-form by supplying plastic materials such as ceramics to the mold of the press-forming equipment in a state close to closing the mold, which shortens the closing time of the mold and also allows the plasticity of ceramics etc. molten at high temperatures to be reduced. The temperature of the material can be suppressed as much as possible, and the plastic material can be fluidly filled into the mold cavity and press-molded.

[Brief explanation of drawings]

Fig. 1 is a partially omitted front sectional view of an embodiment of the present invention, Fig. 2 is a partially omitted side sectional view of the mold part of the same, and Fig. 3 is a slide of the same as the above following the balance support device. FIG. 3 is a control block diagram for press forming. 1...Press molding device, 4...Slide, 5...
... bed, 6 ... mold, 7 ... upper mold, 9 ... lower mold, 10 ... plastic material, 17 ... equilibrium support device, 21 ... cavity.

Claims (1)

[Scope of Claims] 1. A press molding device in which a lower mold is attached to the bed side, an upper mold is attached to a slide facing the bed, and the slide is moved up and down with a pressure cylinder for pressing. A material supply nozzle is provided in the mold or the lower mold, an injection plunger with a predetermined capacity is connected to the material supply nozzle, and the pressure cylinder is operated to separate the upper mold and the lower mold. When the mold approaches a state close to closing, a predetermined amount of plastic material such as ceramics in a molten state is formed in the upper mold and the lower mold from the injection plunger through the material supply nozzle in the upper mold or the lower mold. 1. A method for press-molding a plastic material such as ceramics, the method comprising: supplying the plastic material such as ceramics into a mold to flow-fill the material into a predetermined cavity of the mold and press-molding the material. 2. The slide, which has been lowered with the upper mold attached, is balanced and supported by a balance support device installed in the bed of the press molding device, and while the slide is balanced and supported by the balance support device, a plastic material such as ceramics is placed in the mold. A method for press-molding a plastic material such as ceramics according to claim 1, which comprises fluidly filling a predetermined cavity and press-molding the material.