JPH0224642B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an apparatus for producing ceramic intermediate products, which comprises two mold halves, which are connected to an adjusting device. , in particular adjustable between a relative open position and a relative closed position (see FIG. 1) by means of two movable parts forming the press, and of these two mold halves. In the closed position, a closed mold cavity is formed, which mold cavity has at least one feed opening for supplying powdered ceramic molding compound and at least one suction opening for creating a vacuum. and further cooperating with the sealing surface supports of said mold halves movable relative to each other so as to abut against each other during a closing movement of said adjusting device and, in contrast, to move away from each other during an opening movement of said adjusting device. and is provided with a sealing surface which seals the mold cavity in the relative closed position of the two mold halves.

PRIOR ART A device of this type is known, for example, from German Patent No. 31 01 236.
In this known device, a vacuum is supplied to the mold cavity when the powdered ceramic molding compound is introduced into the mold. Due to this vacuum, the powdered ceramic material is drawn into the mold cavity, and an air flow is supplied to the molding material at the point where it enters the mold cavity or at a point adjacent to this point. The molding material is distributed within the mold cavity with the aid of a molding material. Also, this Federal Republic of Germany patent no.
According to the method disclosed in No. 3101236, the speed at which the sucked-in molding material particles impinge on the suction opening is kept low at the start of the suction process as follows. This means that it allows the suction operation while avoiding the formation of blockages in the suction openings, which would impede the suction of air, due to molding material particles that are closely stacked and are possibly destroyed when they collide. At the beginning of the suction process, the speed with which the molding material particles impinge on the suction opening is kept low so that filter packets as part of the intermediate product are formed at the suction opening. According to this method, the material is sufficiently filled into the mold cavity by suction, and at this time, the molding material in the mold cavity is sufficient to allow the predetermined operation without damaging the intermediate product. Pre-compressed. In particular, it is essential that the shoot head, which first supplies the vacuum and then the molding material and possibly the air flow, is replaced by a press head without causing extensive destruction of the intermediate product. It has been proven that it is possible. In spite of this, when lifting the shoot head, although the cause is not clear, it is probable that many damages are still formed on the intermediate product.

OBJECT OF THE INVENTION It is therefore an object of the invention to significantly reduce, by relatively simple measures, the damage caused to the intermediate product when lifting the shoot head.

According to the invention, which solves the above problem, a spring device is provided between at least one part of the adjusting device and the sealing face support of the mold half belonging to this part. , the spring device is loaded during the closing movement of the adjusting device and unloaded during the opening movement of the adjusting device.

Effect According to an arrangement of the invention, the seal existing between the two mold halves is gradually exposed to pressure when the mold halves assume a relative closed position. Similarly, the sealing pressure is gradually released as the two mold halves are pulled apart from each other. As long as the spring device is fully compressed, the seal is under full seal pressure. As the parts of the adjusting device supporting the mold halves begin to move away from each other, the sealing pressure gradually falls from the value of full sealing pressure to a value of zero. This sealing pressure value of zero is obtained when the precompressed spring device is completely decompressed. In this way, when the sealing pressure is gradually released, gradual pressure compensation is possible between the atmosphere and the mold cavity. Due to this gradual pressure compensation, the damage or destruction caused to the intermediate product when the mold halves are separated from each other is significantly reduced compared to the prior art. The reason for this is not yet fully understood, and other reasons may exist, but instead, in a fully compressed state, the spring device is compressed until it "locks" or It has been shown that, since the stopper can bridge the spring arrangement, a sealing pressure greater than that created at maximum compression of the spring arrangement is transmitted. It has also been proven that even in the maximum unloaded state of the spring arrangement, there is still a certain preload in the spring arrangement.

Embodiments According to an embodiment of the invention, one of the two mold halves is preferably designed as a pressure-equal press mold half with a pressure-equal press diaphragm, the press diaphragm having a One side is in contact with a portion of the mold cavity and the other side is loaded with a pressure fluid, in particular a pressure liquid. The other mold half, on the other hand, is formed by a shoot head with a mold cavity and a limiting surface facing the press diaphragm, which has a feed opening, a suction opening and, if appropriate, an air supply opening. have. In such a construction, the sealing surface support is formed by the edge area of the pressure-equalizing pressed diaphragm and the diaphragm contact ring of the shunted head, which rests on this edge area.

The supply opening for the ceramic molding compound is mounted in the shoot head in such a way that it opens in the central region of the mold cavity, whereas the suction opening opens in the edge region of the approximately largest circumferential extension. It is attached to the shoot head so as to open into the hollow chamber. Experience has shown that with such an arrangement, a complete filling of the mold cavity over its entire volume range and an almost uniform sealing of the intermediate product is obtained.

The mold cavity is evacuated to a pressure of 0.7 bar to 0.1 bar. The impingement speed of the molding material particles that are drawn in and impinge on the suction opening is suppressed for the same purpose as disclosed in the above-mentioned German Patent No. 31 01 236. This means that air leakage is suppressed by supplying air leakage into the suction conduit connected to the suction opening and/or into the mold cavity.
The speed at which the drawn-in molding material particles impinge on the suction opening is also controlled by throttling the drawn-in air. In particular, the impact velocity of the molding material particles is controlled to such an extent that at least a portion of the molding material particles remain unbroken (i.e., especially for molding materials with different particle sizes, especially those where the size of each particle is relatively large). ).

In particular, ceramic materials which have been reduced in size by spray drying are used as molding materials (see German Patent No. 31 01 236).

The mold halves are vertically movable relative to each other. In this case, the lower mold half is formed by a pressure-equalizing mold half and the upper mold half is formed by a shoot head.

The sealing face support, supported by a spring device, is firmly attached to the associated mold half;
The part of the adjusting device on which the mold half supports the mold half is supported by a spring arrangement consisting of a number of pressure helical springs arranged separately around the outer periphery of the adjusting device.

The compression coil spring is replaced by a disc spring packet or the like.

The mold half, which is supported by a spring device, is guided by a number of guide pins in the part of the adjusting device that supports this mold half.

The shoot head according to DE 31 01 236 is generally intended for forming intermediate products and not for final pressing. The shoot head is therefore replaced by a press head after the mold cavity has been filled with material. In principle, however, it is also possible to carry out the pressing within the mold halves in which the intermediate product is formed.

Assembly of the device is made easier if the shoot head is supported by a spring device, with a part of the adjustment device supporting this spring device. This means that the pressure-equalizing press mold can be fixedly mounted, in particular on the press.

In order to carefully demold the intermediate product formed in the mold cavity, the adjusting device has a drive with a drive control, the drive control being configured to
During the opening movement of the adjusting device, the adjusting device is controlled at a first lower opening speed until the spring device is unloaded, and then at a second higher opening speed. Such high opening speeds are desired when operating takt times are high. On the other hand, the small opening movement for starting the opening movement causes the vacuum to slowly release in the mold cavity.

Embodiment Next, the structure of the present invention will be specifically described with respect to an embodiment shown in the drawings.

In FIG. 1, one of the lower mold halves is designated by the reference numeral 10, and the other upper mold half is configured as a shoothead 12 for supplying vacuum and molding material. The lower mold half 10 herein includes:
The adjusting device 15, 14 rests on one possible part 15, which is designed as the basic frame of a ceramic press, for example a hydraulic ceramic press. The shoot head 12 is
In the usual form a press or said adjusting device 15, 14
part 14 of the adjusting device configured as a yoke, guided by a guide frame (not shown) of
It is located in The drive for vertically displacing the two movable parts 15, 14 of the adjusting device with respect to each other is designed as a slide pin 30. A drive control unit 32 is assigned to this drive, which is operated, for example, hydraulically.

The lower mold half 10 surrounds a pressure equalizing press diaphragm 16 which is received in a pressure chamber 18 of the lower mold half 10. The pressure chamber 18 is connected via a distribution channel 20 to a hydraulic pressure fluid connection 22.
It is connected to the. The sealing edge 24 of the press diaphragm 16 is fixed to the mold half 10 by a fixing flange 26 . This sealing edge 24 is a sealing surface support portion having a sealing surface 24a.

Shout head 12 includes a body 12a, a central molded body 12b, and a diaphragm contact ring or sealing surface support 12c. Center molded body 1
2b and the sealing surface support portion 12c are firmly connected to the main body 12a. The diaphragm contact ring or seal surface support portion 12c is connected to the seal surface 12r (second
(see figure).

A supply chamber 12d for powdered ceramic material is formed in the main body 12a and the central molded body 12b, which is connected to a molding material storage chamber via a supply conduit 12e. A supply opening 12f is provided at the center of the central molded body 12b. This supply opening 12
f can be closed by a closure and flow conduit 12h. According to FIG. 2, the closure and flow conduits are in the closed position. This closure and flow conduit is height adjustable in the direction of the arrow by means of a hydraulic power device 12g. The closure and flow conduit 12h is hollow and
It has air flow holes 12i and 12k at the upper and lower parts, and through these air flow holes 12i and 12k, the air guided through the air connection part 12m is molded into powdered ceramic near the supply opening 12f. Materials are supplied.

An annular gap 12l is present between the central molded body 12b and the diaphragm contact ring or sealing surface support 12c;
l is connected to the annular chamber 12n. The annular gap 12l acts as a suction opening, the details of which will be described later. The annular chamber 12n is connected to the low pressure vessel via a vacuum conduit 12o.

According to FIG. 1, the shoot head 12 is in a closed position relative to the mold half 10 with the sealing surfaces 24a and 12r abutting each other (at this time, the sealing edge 24 and the diaphragm contact ring or seal The seal between the surface support 12c is fully functional). A mold cavity 28 is formed between the press diaphragm 16 and the central molded body 12b.

A slide guide formed by a number of slide pins 30 arranged in the component 14a of the section 14 is arranged between the section 14 and the main body 12a of the shoot head 12. This slide guide 30 engages with a slide bush (drive control device 32) of the main body 12a (see FIG. 1).

As shown in FIG. 2, a spring arrangement formed by a number of biasing coil springs 34 is arranged between the component 14a of the section 14 and the body 12a of the shoot head 12. The pressing coil spring 34 is guided by a guide pin 34a. This guide pin 34a is screwed into the main body 12, and its pin head 34b is inserted into the hole 14 of the portion 14a.
invade inside b. The pressing coil spring 34 is connected to the yoke 1
4 and the sealing surface 12c.

According to FIG. 2, the shoot head 12 is lifted out of the component 14a of the section 14 under the spring action of the helical pressure spring 34. According to Figure 1,
Since the yoke 14 is lowered until the pressing coil spring 34 is completely compressed, the diaphragm contact ring or sealing surface support portion 12c is subjected to the spring action of the compressed pressing coil spring 34, and the sealing edge or sealing surface is moved downward. It is pressed against the support part 24. In this state shown in FIG. 1, the mold cavity 28 is filled. For this purpose, the closure and flow conduit 12h is brought into the position shown in FIG. 1, in which the feed opening 12f is open. Since vacuum is supplied to the annular chamber 12n by the vacuum conduit 12o, the annular gap 12l (suction opening)
A vacuum is created in the mold cavity 28 via. Under the action of this vacuum, ceramic powder molding material is sucked into the mold cavity 28 from the supply chamber 12d through the supply opening 12f, but at this time, the molding material flows inside the mold cavity 28. Evenly distributed by air. As soon as the mold cavity 28 has been filled, the part 14 is lifted up, the shoot head 12 and the sealing face support 12c being initially held in the position shown in FIG. 1, and the pressure helical spring 34 being slowly released. Therefore, the sealing pressure between the sealing surfaces 24a and 12r is slowly released. When this sealing pressure is released and the sealing pressure becomes zero, atmospheric pressure enters the mold cavity 28 through the sealing points 24a and 12r, so that the mold cavity 28 is gradually evacuated. Due to this gradual evacuation, when the shoot head 12 is lifted out of the lower mold half 10, that is to say when the central molded body 12b is lifted out of the intermediate product formed in the mold cavity 28, Destruction or damage to the pre-compacted intermediate product is avoided. Vacuum conduit 1 to the atmosphere
Since it is impossible to completely evacuate the intermediate product by simply connecting 2o, the pre-pressed intermediate product is The product will be handled with care. In addition, in order to carefully handle the pre-pressed intermediate product, it is necessary to
It is also necessary to slowly release the pressure applied by the

By releasing the pressure coil spring 34, the shoot head 12 is completely raised and a press head is inserted in its place. The central compact of this press head corresponds approximately to the central compact 12b.
After inserting the press head, an equal pressure press is carried out. That is, the liquid under high pressure is supplied through the pressure liquid connection 22 via the distribution channel 20 to the back side of the press diaphragm 16 in the pressure chamber 18, so that the pre-pressed intermediate product is finally Pressed.

According to FIG. 1, in the press diaphragm 16,
A number of cutouts filled with pressurized liquid are provided. These notches have the purpose of relieving the internal stresses exerted on the thick press diaphragm 16 and providing it with structural stability that facilitates the acquisition of the desired external contour shape of the mold halves. ing.

Furthermore, according to FIG. 1, the drive control device 32 causes a slow relative movement of the two parts 15, 14 at the beginning of unloading the pressure coil spring 34, so that the vacuum in the mold cavity 28 is gradually reduced. The intermediate product formed and released is very carefully evacuated. Starting or shortly after the compression coil spring 34 is fully extended, the drive control 32 quickly raises the portion 14. In this way, an optimal combination of careful handling due to slow evacuation of the mold cavity 28 and high working speed of the entire device is obtained.

In addition, in order to maintain the press diaphragm 16 in contact with the lower half of the mold even if a vacuum is formed in the mold cavity 28, and to prevent the mold cavity from deforming due to the formation of a vacuum in the mold cavity, At the same time that a vacuum is applied to the mold cavity 28 for the purpose of inserting the molding material, a vacuum is also applied to the underside of the press diaphragm 16 .

Effects As described above, according to the apparatus of the present invention, it is possible to significantly reduce damage to intermediate products when lifting a shoot head by relatively simple means.

[Brief explanation of drawings]

FIG. 1 shows a third embodiment of an apparatus according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view along line FIG. 2, FIG. 3 is a cross-sectional view along line FIG. 10...Mold half, 12...Shoot head, 1
2a...Main body, 12b...Molded body, 12c...Seal surface support portion, 12d...Supply chamber, 12e...Supply conduit, 12f...Supply opening, 12g...Power device, 12h...Closing and flow-through Conduit, 12i, 1
2k...Air flow port, 12l...Annular gap,
12m...Air connection, 12n...Annular chamber, 12
o...Vacuum conduit, 12r...Sealing surface, 14,1
5... Adjustment device, 14a... Component, 14b...
Hole, 16...Press diaphragm, 18...Pressure chamber, 20...Distribution passage, 22...Pressure liquid connection, 24...Seal edge, 24a...Seal surface, 2
6...Fixed flange, 28...Mold hollow chamber, 30...
...Slide pin, 32...Drive control device, 34...
...Press coil spring, 34a...Guide pin, 34
b...Pin head.

Claims (1)

[Scope of Claims] 1. An apparatus for manufacturing a ceramic intermediate product, comprising two mold halves 10 and 12,
These two mold halves 10, 12 can be adjusted between a relative open position and a relative closed position (see FIG. 1) by two movable parts 15, 14 forming an adjustment device. Possibly, in the closed position of these two mold halves 10, 12 a closed mold cavity 28 is formed, which mold cavity 28 has at least one chamber for supplying powdered ceramic molding compound.
one supply opening 12f and at least one suction opening 12l for creating a vacuum;
Furthermore, the mold halves 10 are movable relative to each other,
12 sealing surface supports 24, 12c which collide with each other during the closing movement of the adjusting devices 15, 14, whereas they move away from each other during the opening movement of the adjusting devices 15, 14; In the version in which sealing surfaces 24a, 12r are provided which seal the said mold cavity 28 in the relative closed position of the parts 10, 12, at least one movable part 15 of the adjusting device and the associated mold half are provided. A spring device 34 is provided between the portion 12 and the sealing surface support portion 12c, and the spring device 34 is connected to the adjustment device 1.
Device for producing ceramic intermediate products, characterized in that it is loaded during the closing movement of the adjusting devices 15, 14 and unloaded during the opening movement of the adjusting devices 15, 14. 2. One of the two mold halves 10, 12 is constructed as a pressure equalizing press mold half 10 and has a pressure equalizing press diaphragm 16, one side of which is connected to the mold. Hollow chamber 28
The other side is loaded by a hydraulic pressure liquid, whereas the second side
The other half 12 of the two mold halves 10, 12 is configured as a shoot head with a mold cavity/limiting surface 12b located on the side opposite the press diaphragm 16, which shoot head is connected to the feed opening 12f. 2. The device according to claim 1, further comprising a suction opening 12l. 3. The sealing surface support 24, 12c abuts the edge area of the pressure-equal press diaphragm 16 and the edge area of the pressure-equal press diaphragm 16,
and a diaphragm contact ring provided on the shoot head.
Apparatus described in section. 4. A supply opening 12f provided in the shoot head for supplying the molding material opens into the central area of the mold cavity 28, and a suction opening 12f provided in the shoot head for creating a vacuum.
4. The device as claimed in claim 2, wherein the mold cavity 28 opens into the mold cavity 28 in the edge region of approximately the maximum circumferential extension of the mold cavity 28. 5. Device according to any one of claims 1 to 4, characterized in that the mold halves 10, 12 are vertically movable relative to each other. 6. The method according to claim 5, wherein the lower mold half 10 is formed by a pressure-equalizing press mold half and the upper mold half 12 is formed by a shoot head. Device. 7. The sealing face support 12c supported by a spring device 34 is fixed to the associated mold half 12, which mold half 12 supports this mold half 12;
The device according to claims 1 to 6 is supported in part 14 of the adjusting device by a spring device 34 consisting of a number of pressure helical springs arranged in sections around the outer periphery of the adjusting device. The device according to any one of the items. 8 Mold half 12 supported by spring device 34
8. Device according to claim 7, characterized in that the part 14 of the adjusting device supporting this mold half 12 is guided by a number of guide pins 30. 9. Device according to one of the claims 2 to 8, characterized in that after the mold cavity 28 has been filled with molding compound, the mold half 12, which is designed as a shoot head, is replaced by a press head. . 10 12 configured as a shot head is supported by a spring device 34 on the part 14 of the adjusting device, supporting this spring device 34. Apparatus described in section. 11 The adjusting device has a drive device 30 with a drive control device 32, which drives the adjusting device 15, 14 in the first position during the opening movement of the adjusting device until the spring device 34 is unloaded. 11. The device according to claim 1, wherein the device is controlled at a lower opening speed and then at a second higher opening speed.