WO1991010545A1

WO1991010545A1 - Apparatus for molding under high pressure

Info

Publication number: WO1991010545A1
Application number: PCT/JP1991/000041
Authority: WO
Inventors: Keiichiro Isomura; Toshihiko Funahashi; Kazuki Ogasahara; Yasuhiro Habu; Susumu Shinohara; Masakuni Esaki; Hideo Yoshikawa
Original assignee: Kawasaki Steel Corporation; Shin-Ei Kiko Co., Ltd.
Priority date: 1990-01-18
Filing date: 1991-01-17
Publication date: 1991-07-25
Also published as: EP0463179A1; EP0463179A4; KR920700864A

Abstract

This invention provides an apparatus usable for molding under high pressure, in which, when slip casting is applied to super-fine powder for porcelains and fine ceramics, no clogging occurs and high efficiency as well as high accuracy is exhibited in molding. The apparatus is a high pressure casting molding apparatus for slip casting provided with an air-permeable mold composed of 10 to 50 % by weight of BN and ceramics, and with a pressure intensifier for pressurizing, press having mold release function, defoaming and stirring vacuum unit, pressure intensifier, ultrasonic cleaning unit, high pressure cleaning and drying unit, and microwave generator, whereby molding, release of mold, cleaning, and drying are performed in succession and excellent mass-production capability is exhibited.

Description

Documents High-pressure cycling molding device technology

The present invention relates to a high-pressure injection molding device. More specifically, a slip casting of high-quality molded products in a short time using a special mold for slip casting, which has particularly fine pores, long life, high strength, and good demoldability, is used. The present invention relates to a compression molding apparatus. Background technology

Slip casting is a type of powder molding technology, and is a technology that is particularly used in the manufacture of ceramics, tableware, insulators, and so on. In recent years, it has been applied to the production of fine ceramics such as alumina, silicon nitride, and zirconia, and is expected as a molding technology for industrial parts.

A conventional slip casting apparatus is shown in FIG. The prepared slip is put into a vacuum defoaming stirrer 2 and the slip is stirred and simultaneously defoamed with a vacuum pump 1. When the defoaming force is completed, the pressure in the stirrer 2 is set to normal pressure, and then the pressure is applied to the stirrer 2 to send the slip to the kinki table 3 by pressure. The mold 4 previously set on the insert table 3 is filled with slip and molding is performed. 5a to 5e are valves, 6 is a pressurized gas source, and 6a is a pressure reducing valve. Conventionally, a gypsum mold has been used as the mold 4. Gypsum molds have advantages such as excellent water absorption, demoldability, dimensional accuracy, and the ability to form inexpensive large complex shapes. On the other hand, gypsum molds have poor water resistance, compressive strength, and abrasion resistance, and also have drawbacks such as Ca ²⁺ ions in gypsum being eluted and mixed into the substrate. You. In addition, since the water in the slip is absorbed by the gypsum using the capillary phenomenon generated in the gypsum, and the inlay is formed by this, the formed body having a wall thickness of about 5 to 7 mm is 10 to 20. You need minutes of inking time. In addition, the second meating time is longer than the first meating time, and its ability decreases with the number of uses. To compensate for these drawbacks, multiple plaster molds must be used.

Against this background, various types of molds made of other materials have been developed in order to overcome the disadvantages of the plaster molds. Main materials are resin, resin-ceramics, metal-ceramics, and metals. However, these molds are limited to some ceramic molding applications because of the following disadvantages. For example, there is Japanese Patent Application Laid-Open No. 63-212105.

(1) The pore size is larger than 3, and the fine particles cause clogging of the mold, resulting in poor mold release.

(2) Since it contains iron, etc., it is mixed into the substrate.

(3) Since machining of the mold is not easy, it is necessary to perform processing after molding to increase surface accuracy and to finish complicated shapes with ultra-thin wall and ultra-fine details with high dimensional accuracy. . Disclosure of the invention

The present invention aims to solve the problems of conventional slip casting by providing an apparatus for performing high-quality molding in a short time by using a sleeve casting mold having the following characteristics.

(1) It must have a fine pore size that does not cause clogging even when using ultrafine powder for fine ceramics as well as powder for ceramics.

(2) A long-life type with excellent water resistance and pressure resistance that does not alter or wear the mold surface even after many uses. ③ not normal pressure type only, by pressing up 1 0 0 0 kg Bruno cm ^{2, and} can be molded in a short time.

ること Good removability.

良い Good molding accuracy.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a gas-permeable type III made of 10 to 50% by weight of boron nitride and at least one other ceramic or sox component; A filling table having a mold device, a vacuum defoaming stirrer for stirring and defoaming the filling slip, and a filling slip provided between the filling table and the vacuum defoaming stirrer. A high-pressure injection molding apparatus comprising: a pressurizing intensifier for pressurizing; and a pressurizing / depressurizing line connecting the pressurizing table, the vacuum defoaming stirrer, and the pressurizing pressurizing machine. . If this device is further equipped with an ultrasonic cleaning device and a Z or drying device, it is possible to form a slip having very fine particles efficiently without clogging, and it is preferable.

In addition, the apparatus of the present invention includes a type cleaning apparatus, a cycling type drying apparatus, a high-pressure * injection molding apparatus, and a demolding apparatus, which are successively moved to the positions of these apparatuses. This is a high-pressure injection molding machine capable of high-efficiency production by repeated and continuous molding. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is a block diagram showing the overall configuration of the apparatus of the present invention, Fig. 2 is a detailed view of the vacuum defoaming stirrer in Fig. 1, Fig. 3 is a detailed view of a slip intensifier, Fig. 4 FIG. 5 is a partial detailed view of the slip-in table, FIG. 5 is an explanatory view of the operation of the slip intensifier, FIG. 6 is a side view of another embodiment of the present invention at the end of molding, and FIG. 8 is a plan view of another embodiment of the present invention, FIG. 9 is a side view of FIG. 8, FIG. 10 is a front view of FIG. 8, FIG. Figure 1 shows the conventional device FIG. 3 is an explanatory diagram showing a configuration and an operation of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

The present inventors have compared and studied various materials as a mold for slip casting. As a result, they have found that, when a composite sintered body composed of boron nitride and other ceramic components is used, a mold for slip casting, which has very excellent characteristics as compared with the conventional one, can be obtained. Based on this knowledge, we have completed a mirror-injection molding device that utilizes the advantages of type III.

First, the cinnamon type will be described in detail. We considered BN as a base, because it is difficult to get wet with the substrate and easy workability. However, BN is difficult to sinter, and usually has a problem that it must be sintered by a high-pressure breath method. Another problem is that the wear resistance S is low. Therefore, the present inventors have considered combining BN with another ceramic component which is densely sintered by normal pressure or atmospheric pressure sintering, and is excellent in wear resistance and pressure resistance. The intention is that

(1) BN hinders sintering of other ceramics, causing pores to form. (2) Supplement wear resistance while taking advantage of the advantages of BN.

This is a combined effect.

In addition, in order to ensure sufficient water absorption of the cylindrical shape, the pores must be continuous pores connecting the inner and outer surfaces of the cylindrical shape. Type 铸 needs to have air permeability. In鐯型used in the present invention, other ceramic components to be combined with the BN, and _{_{S i 3 N 4, S i}} C, SI ALON, Zr0 2, ΑΆ 2 0 3, ΑΆ N, resistance such as mullite Materials with excellent wear characteristics can be used. Also, it may be used wood charge a composite of two or more depending on the purpose, such as A ₂ Os one Zr0 _2.

BN content The more BN, the better the mold release and workability, but the pressure resistance Degree and hardness decrease. Therefore, the BN content may be adjusted in consideration of these factors depending on the material to be molded. Further, the pore diameter and the porosity can be arbitrarily adjusted depending on the particles and the content of the starting material, so that the particle size and the content of the material to be molded may be adjusted. Preferably, the weight ratio of BN to the total weight of BN and other ceramic components is 10 to 50%, the average pore diameter is 0.;! To 2 m, and the porosity is 10 to 40%. Is desirable.

By using such a mold, even when a fine particle raw material is handled, there is no clogging force, the demolding property is good, considerable high-pressure molding is possible, and mass productivity can be improved. Also, because of its excellent wear resistance, the surface accuracy of the molded product can be kept constant. This makes it possible to handle products with strict quality requirements, such as automotive parts. Furthermore, since this mold can be processed with high precision using a processing machine after firing, as in the case of the breath type and the injection type, the precision of the molded product is also very good.

Next, a description will be given of a slip casting apparatus using the above-mentioned type. The conventional rust type has a problem that the pressure resistance performance is small, and even if the pressure resistance performance is high, the demolding property is poor and clogging occurs. The type III of the present invention has the advantages of high pressure resistance and releasability when performing slip casting, and also has the advantage of not clogging even with ultra-high pressure slip casting.

When pressure is applied to the slip with the device shown in Fig. 11, the conventional device, which pressurizes through a compressed gas, increases the complexity of the device and increases the equipment cost S. In addition, if the device ruptures, it will be extremely difficult. There are problems such as danger. For this reason, in order to make use of the characteristics of the above-mentioned cylindrical shape and to perform high-pressure cycling molding, it is necessary to use a slip casting device with high safety and high productivity. The present invention has solved this problem, and the apparatus of the present invention can pressurize and press the slip with a commonly used compressed gas of less than 1 O kgZcm ² . An embodiment of the apparatus of the present invention will be described in detail with reference to FIGS. FIG. 1 is a block diagram showing the whole of one embodiment of the device of the present invention. The vacuum defoaming agitator 2 is connected to a mold 4 in a filling table 3 by a pipe 12, and a slip intensifier 11 is connected between them. The vacuum pump 1 and the pressurized gas source 6 are connected to a vacuum defoaming stirrer 2 and a mirror type table 3 and a quin type 4. The cypress 4 has a clamp cylinder 8 s' mounted and a hydraulic unit 9 attached.

Fig. 2 is a detailed view of the vacuum defoaming stirrer 2 in Fig. 1; Fig. 3 is a detailed view of the slip press 11 in Fig. 1; FIG. 5 is a detailed view of a portion of the table 3, and FIG. The operation of this embodiment will be described below with reference to FIGS. The prepared slip is poured into a vacuum defoaming stirrer 2, covered, and stirred with a vacuum pump 1 in a vacuum state of 700 mmHg or more. When the stirring and defoaming power is completed, the valve 5c is closed and the valve 5b is opened to make the inside of the vacuum defoaming agitator normal pressure. Set the cypress type 4 in the cypress table 3. Next, the pressure to the slip is adjusted to 0.1 to 2 kg Z cm ² by the pressure reducing valve 6a, the valves 5a, 5e, 5mm are opened, the valve 5b is closed, and the compressed air from the pressurized gas source 6 is closed. The slip is pumped by air, and the lower chamber 11c (Fig. 5) and the mold 4 of the compressor 11 are filled with the slip. In this case, the lower piston 11a of the intensifier is pressurized and lowered by the pressure reducing valve 6b and the valve 5g in advance. This is to prevent air bubbles from entering the pickpocket and the soap. When filling the chamber 11c with slip, the piston area ratio between the lower piston 11a and the upper piston 11b is greatly increased (for example, 1: 125), so that the piston of the upper piston is not sealed. Large resistance. In this case, setting the pressure reducing valve 6 d to a pressure of 4~8 k gZ c rn ^2, a slip down the chamber 1 1 c easily by adding a supplemental pressure to the slip pressure by opening the valve 5 h It becomes possible to fill. I mean It uses auxiliary pressure to eliminate the large sealing resistance on the large piston side of the booster.

Next, close the valve 5 f, set the pressure of the pressure reducing valve 6 b to 5 to 9.9 kg / cm ² , and open the valve 5 g. The pressure acts on the piston 11b, and the slip pressure filled in the lower chamber 11c acts in the mold 4 to accelerate the molding speed. When molding is completed, open valve 5 g and open valves 5 f and 5 b. Next, the valve 5i and the pressure reducing valve 6c are opened, and the molded body is adsorbed on the upper mold and raised. Next, close the valve 5i, prepare the pallet under the molded product, and open the valve 5k. The valve 5d is a valve 8 for residual slip discharge, and the valves 9 are a clamp cylinder and a hydraulic unit, respectively. It is possible to design a mass production system by adding a molded product demolding device, electric circuit, solenoid valve, sensor, etc. to this device to automate it.

Next, FIGS. 6 and 7 show an apparatus according to an embodiment of the present invention for continuously performing molding. The system shown in FIG. 6 shows a loading table 3 having only one set of mold 4 and performing from molding to washing and drying. FIG. 6 shows a single type 4 equipped with a normal-temperature pumping device 21, a high-temperature pumping device 22, a washing water device 23, an ultrasonic cleaning device 24, and an operation unit 26 thereof. Fig. 6 shows that after molding the molded body 15 with the mold 4, air blow is applied to the lower mold 4a, vacuum is applied to the upper mold 4b, and the molded body 15 is brought into close contact with the upper mold 4b. This shows a state in which it is pulled up. Next, an air blow is applied to the upper mold 4 b to take out the molded body 15.

FIG. 7 shows a cleaning step following the state of FIG. In FIG. 6, the washing water tank 24 waiting on the side of the cymbal 4 is guided by the horizontal guide 25 and the vertical guide 27, and as shown in FIG. Move to a position surrounding the lower mold 4a, and lower the upper mold 4b into it. Next, the cleaning liquid is introduced from the cleaning water device 23, and the ultrasonic wave and the air from the back of the mold are removed. Clean the mold 4 using high-pressure, high-pressure air such as air blow (air pressure 1 to 5 kgf / cm ² ) or steam. After washing, the washing solution is removed by a washing water device, and the type 4 is dried. In this case, it is possible to remove water in a short time by drying the mold 4 using a microwave generator. Fine ceramic particles have very fine particles, so they adhere to the surface of the porous mold and reduce the molding speed of the molding equipment. Ultrasonic cleaning is performed to prevent this and shorten the cleaning time by air blow. This is not possible with conventional gypsum molds or the like, but ultrasonic cleaning is not possible, but there is no problem with the BN-based cypress molds.

Next, another embodiment of the continuous molding apparatus will be described with reference to FIGS. 8, 9 and 10. FIG. This embodiment is an example of a system provided with a turntable type 铸 -shaped moving device. Around the turntable 70, a type I cleaning device 30, a type I drying device 40, a high-pressure / injection molding device 50, and a demolding device 60 are provided. To rotate around these devices.

The cycling-type cleaning device 30 includes an arm 32 for chucking and raising and lowering the upper die of the 鐯 type, and a cylinder 31 for raising and lowering a washing water tank 33. The water tank 33 can be provided with an ultrasonic cleaning device. The cleaning liquid supply / drainage device 34 supplies the cleaning liquid to the water tank 33 via the hose 35.

Next, in the drying device 40, a pipe for blowing a high-temperature drying gas in a cross shape is provided. This piping is also provided from a device in the base 90 through the rotation shaft of the turntable 70, and is supplied with a drying gas. '' The high-pressure / cooking device is equipped with a pressing cylinder 51 on the frame 51, sandwiches a square between the upper and lower die sets 53, 53, and presses in the slurry from the slurry piping by the same device as in Fig. 1. Perform slip casting. Slurry piping is also provided inside the rotary shaft of the evening table 70. When the molding is completed, the demolding device operates in the same manner as the device in FIG. The demolding device 60 includes a cylinder 61 for operating an arm 62 for lifting the upper die of the 铸 type, and a rotating arm 63 for taking out a molded product and placing it on a conveyor 64. The operation of the rotating arm 63 is operated by a simple robot 64.

The drive unit 80 of the turntable 70 is used for cleaning the mold in the mold washing apparatus 30, the mold drying apparatus 40, the high pressure, the molding apparatus 50, and the demolding apparatus 60. The turntable 70 is operated intermittently in the direction of the arrow 71.

With this equipment, molding, demolding, washing, and drying can be performed by separate equipment, shortening the process of one cycle and enabling mass production. There is no limitation on the number of 鐯 types arranged on the turntable 70.数 The number of molds can be determined most efficiently by considering the molding time and the processing time from demolding to drying.

Table 1 shows the time up to demolding when molding was carried out using the present invention's apparatus shown in Fig. 1 using a ceramic slip. Table 1 shows that molding is quick, but it takes time to wash and dry. If the washing and drying steps are carried out quickly, productivity will improve. This is made possible by the spalling characteristics and heat resistance of the BN- 铸 type. Clogging that occurs when a slip having fine particles is formed can be eliminated by shortening washing and drying, and the apparatus of the present invention improves productivity.

As is clear from these results, according to the present apparatus, the applied pressure can be sufficiently increased, and as a result, high-speed molding can be performed.

The molding time with the conventional gypsum mold is 2 kg / cm ² at a pressure, and it takes about 10 to 20 minutes for the thickness of the molded body to be about the same. And force> and, Suritsu Bed casting apparatus intensifier at pressure 2 0 0 kg / cm ² by up using the present invention, 1 0-2 0 seconds if the molded body thickness is 5 mm about things in ceramics Suribbu, A £ ₂ 0 ₃ slip 5-1 0 seconds, 5-8 seconds S i ₃ N ₄ slips. This molding time will be shorter if the pressure of the compressor is increased. If the slip is pressurized to a pressure of 1 O Ok gZcm ² or more by a pressure intensifier, bubbles mixed into the surface of the compact during slip pressure feeding are discharged during dehydration due to high pressure and do not remain in the compact. This leads to a reduction in the product defect rate.

Table 1 Molded product dimensions 50 mm diameter, 5 mm thickness

Slip Type Stoneware Slip

Viscosity 50000 C Q S

24% moisture in the slip

Moisture completion moisture (removable moisture) 16.5-17.5%

Pressing time (sec)

Pressing force

(kg / cnf) 1 0 1 5 20 25 30 35 40 45 50 55 60

50 19.8 19.0 18.4 17.7 17.4 16.9 16.6 16.4 16.2 16.1 16.0

1 00 19.0 18.3 17.5 16.9 16.3 16.0 15.7 15.3 15.2 15.1 15.0

1 50 18.0 17.2 16.4 15.7 15.3 15.0 14.9 14.9 14.9 14.9 14.9

200 17.5 16.6 15.7 14.8 14.3 14.2 14.2 14.2 14.2 14.2 14.2

Claims

The scope of the claims

A mold having 10 to 50% by weight of boron nitride and at least one other ceramic component and having air permeability; a mold table for gripping the mold and having a demolding device; Vacuum defoaming stirrer for agitating and defoaming, a pressurizing intensifier for pressurizing the squeezing sleeve, a pressurizing and depressurizing line connecting the filling table, the vacuum defoaming agitator and the pressurizing intensifier A high-pressure injection molding apparatus characterized by comprising:

The high-pressure cryogenic molding apparatus according to claim 1, further comprising an ultrasonic cleaning device and / or a drying device.

Ceramic component _{S is N 4> S i C} , SIALON, Z r 0 2>& 2 0 3, AN and the high-pressure鐯込molding apparatus請Motomeko 1, wherein at least one or more selected from mullite.

High pressure characterized by having a mold washing device, a mold drying device, a high-pressure molding device and a demolding device connected in series, and a mold moving device for sequentially moving the mold to the position of these devices. Injection molding equipment.