DD231197A3 - METHOD FOR CASTING CERAMIC FORM BODIES WITH THE IMPACT OF LOW FREQUENCED VIBRATIONS - Google Patents

Abstract

Method for casting ceramic moldings under the influence of mechanical vibrations in order to prevent the typical defects in the casting process, such as the formation of casting grooves, streaks, casting marks and cracks. According to the invention, mechanical vibrations are transmitted to the slurry during the casting process and subsequently thereafter via a device, in order thereby to prevent the solid particles from forming pronounced textures until the start of the cullet attachment. Essential to the invention is the fact that the slurry is "vibrated" from the inside out and the vote of the excitation frequency and the vibration amplitude on the constructive execution of the device, which dips into the slurry and low-frequency mechanical vibrations in the mold on the slip.

Description

VE Scientific-technical

Operation ceramics

8250 Meissen, Ossietzkystraße 37 a

Title of the invention

Process for casting ceramic moldings under the action of low-frequency vibrations

Field of application of the invention

The invention relates to a method for producing ceramic shaped bodies in the casting process under the action of low-frequency vibrations.

Characteristic of the known technical solutions

Due to the specific composition of ceramic masses, especially castables or slip, it comes during the Eingießvorganges and beyond within the cullet approach to the formation of textures. As is known, the causes for this are, in particular, the anisometry of the clay mineral particles, their swelling capacity and the added liquefaction agents. This leads to the errors occurring in the slip casting process, such as casting grooves, streaks, pouring marks and cracks. These phenomena are tried in practice by the various casting methods to meet. Such methods as fast, even pouring, rotating slurry jet, agitation of the slurry in the mold, are not safe procedures for eliminating the above phenomena / defects. Certainly these phenomena are eliminated by rotation of the mold.

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A disadvantage of the casting process with a rotating mold, the significantly higher investment costs with a higher space requirement and lower labor productivity compared to the so-called.

Another method of forming a uniform and quasi-solid cullet with a short time of drying and drying is the use of electrophoresis, especially for ceramic hollow vessels. From DE-OS 1951 391 a casting method using electrophoresis and mechanical circulation of the cast-in slip is known.

The mechanical circulation known from DE-OS 1951 391 has, according to the invention, the task of avoiding the uneven heating of the casting slip occurring during the application of electrophoresis and thereby the settling of slip lumps on the immersed electrode.

DE-OS-AS 2725 866 discloses a die-casting method for producing leather-hard shaped articles from free-flowing ceramic masses in which the pressure is superimposed under certain conditions on a pulsating pressure in the Hertz range. This superimposed pulsating pressure accelerates the drainage according to the invention, since it improves the compression over the entire molding cross-section. The formation of disturbing textures in ceramic articles can not be counteracted by compacting and thus aligning platelet-shaped mineral particles.

All known methods associated with vibration act on the ceramic slip from the outside. As a result, the formation of disturbing textures can not be effected by a disorientation of the platelet-shaped mineral particles until the end of the body formation.

Object of the invention

The aim of the invention is to find a method which makes it possible to effectively suppress this texture formation during casting without the actual casting process,

Disrupting potting and the subsequent solidification of the cullet and which excludes the disadvantages of the rotating mold casting method ·

Explanation of the essence of the invention

This object is achieved in that mechanical vibrations are transmitted to the slurry via a device and thus the solid particles are prevented until the beginning of the cullet by dehydration, the formation of pronounced textures. Characteristic of the project is that the casting slurry is "vibrated from the inside out" and the shape remains relative to the vibrations at rest. The vibrations may be parallel or perpendicular to the surface of the slip to be introduced. It is crucial that the excitation frequency and the oscillation amplitude are matched to the structural design of the vibration transformer in order to achieve sufficient excitation of the cast-in slip.

The solution according to the invention is demonstrated by the following examples and the figure.

example 1

A vibration transmitter 4 protrudes into the casting mold 2 without touching the bottom of the casting mold 2. This is. By a vibration generator 1 in low-frequency oscillations, z. B. 68 Hz, offset. Subsequently, the slurry 5 is introduced into the mold 2 by the usual method via the pouring opening. The vibrations act at least over the time of pouring, better still beyond, on the slurry 5 and thus prevent the formation of pronounced textures in the body of the molded body 3 ·

According to the invention, the slurry 5 is "absorbed from inside" by the immersed vibration transmitter

Oscillations · The mold 2 remains at rest with respect to these vibrations. It is crucial that an effective excitation of the cast-in slip 5 takes place. For this purpose, the exciter frequency and amplitude are to be adjusted accordingly to the structural design of the vibration transformer 4. A particularly effective excitation of the Schlikkers 5 is achieved by generating longitudinal vibrations in the slurry 5.

Example 2

An oscillating transformer 4 protrudes into the casting mold 2 without touching the bottom of the casting mold 2. The slip 5 is introduced into the casting mold 2 via the sprue opening according to the usual methods and then the vibratory vibrator 4 projecting into the casting mold 2 is driven by a vibration exciter 1 low-frequency vibrations, z. B. 35 Hz, offset. The vibrations act during the body formation on the slurry 5 and thus prevent the formation of pronounced textures in the body of the molded body. 3

Claims (1)

claim Method for casting ceramic shaped bodies under the action of low-frequency oscillations, characterized in that during the pouring of the slurry (5) into the casting mold (2) and / or the time in which the slurry (5) remains in the casting mold (2), mechanical Vibrations from the inside out by means of a in the slurry (5) immersed vibration exciter (4) are transmitted to the slurry (5). For this A Seih <J Documents considered: DE-OS 1951931 (80a, 54/01) DE-OS-AS 2725866 (B 28 B 1/26)