DE10233067A1 - Forming a crystallizable material in the liquid or pasty state - Google Patents

Abstract

The invention relates to a method and a device for the moulding of a crystallisable material, in particular a light metallic material or a polymer material, in the liquid or pasty state, which is left to solidify after the moulding and resultant shaping, whereby the material is made to vibrate, at least in partial regions thereof, before and/or during the moulding and/or the solidification. Where necessary the material is also inoculated with crystallisation seeds, at least in partial regions thereof, during the moulding and/or solidification. A device used for the above comprises a heating element (1, 2), for heating crystallisable material, a moulding unit (5, 6) which defines a moulding cavity (7), a charging unit (3, 4), by means of which the material is pressed into the moulding unit (5, 6) under pressure and a dosing unit (8, 9, 10, 19), for the dosed introduction of the material in the liquid or pasty state from the heater unit (1, 2) into a casting unit (3, 4), whereby the device is provided with at least one unit (S1 - S11) for the generation of mechanical vibrations, at least in partial regions thereof.

Description

The invention relates to a Process for forming a crystallizable material in liquid or pasty Condition and on a device for performing this method according to the preamble of claim 1 and claim 70, respectively.

Such methods and devices the usual have been referred to as casting processes or casting plants since known for a long time. Ultimately, it is always a question of doing this without first defined form / shape present liquid or pasty material to transfer into a mold, the Material is reshaped and during or solidified after solidification becomes. For the material cohesion of the casting it is important that this if possible is homogeneous. Therefore have to even the liquid one or pasty Mass before solidification and the solidification conditions or crystallization conditions preferably be homogeneous.

These are important casting processes Chill casting, especially low pressure chill casting, die casting, the Centrifugal casting and continuous casting.

One is usually used for permanent mold casting Resting permanent form consisting of steel or cast iron in general filled without pressure. The shape of the casting is determined by the mold. When casting full mold also usually also Mold cores made of steel or cast iron are used.

With low-pressure die casting the form is over a riser pipe from the bottom with little overpressure or electromagnetic filled. Freezes after the relatively slow "quiet" filling the casting under the overpressure.

When die casting, the melt or paste mechanically under high pressure and at high speed pressed into a precisely manufactured metal permanent mold. The pressure is maintained until the solidification ends. In contrast die casting is particularly suitable for relative casting thin Castings.

The melt is produced by centrifugal casting in a tubular or ring-shaped mold rotating around its axis guided, in which it solidifies under the influence of centrifugal force. Common castings are rings, tubes, bushes and cylinders, especially ribbed cylinders.

During continuous casting, parts are constant cross-sectional shape and any length, e.g. Solid or hollow profiles, manufactured. The melt is placed in a mold that is open on both sides cast. Cools in the mold the melt so far that there is a load-bearing outer shell on the casting forms. The partially solidified strand is continuously removed from the mold drawn.

Die casting is under the above-mentioned casting process in that in addition to the Pour more fluid Materials also particularly good for suitable for "casting" pasty materials, in which solid particles, especially in crystalline or semi-crystalline Condition. Die casting is particularly suitable for Manufacture of cast parts from aluminum or from aluminum / magnesium alloys.

Common Problems with the casting processes mentioned are segregation and sedimentation as well as the uneven Degassing the melt. this leads to to inhomogeneous cast parts or even to cast parts with uncontrolled Cavities.

Furthermore, the controllability the concentration, distribution and size of the solidification or crystallization nuclei usually poor, resulting in an uneven grain structure, i.e. leads to an inhomogeneous grain size of the casting.

Another problem is the wall friction of the liquid or pasty Material that leads to an uneven speed distribution when dosing the material into the mold and thus into one Verungleichmässigung the dwell time in the filling and dosage range, but also in the different areas of the mold within the casting system. Relative, especially in die casting thin-walled and partly filigree castings, the wall friction has a strong one Influence on the flow behavior of the melt or paste within the mold. To be a complete and quick filling Achieving the mold is therefore a relatively high filling pressure required.

The invention is based on the object Solve prior art problems or their negative effects at least to decrease.

This object is procedurally according to the invention solved, that the material before and / or while of forming and / or solidification at least in some areas Stimulates vibrations.

The vibration excitation can be or tempering area, in a degassing area or in a Filtration area take place.

The material can melt a metal, in particular one containing at least aluminum or magnesium Be melt made in a furnace area, or it can be a polymer melt, in particular a PET Be melt that has been melted in an extruder section. However, the shaping is preferably carried out in a casting mold. The liquid or pasty Material can be added Contain particles and / or bubbles.

In a particularly advantageous embodiment, the vibration is excited by at least one vibration source for mechanical Vibrations, the vibration excitation taking place over a large area via at least one large area element coupled to the vibration source. As a result, a relatively homogeneous vibration state can be achieved over the entire volume of the solidifying casting. This enables the entire volume of the solidifying melt or paste to be influenced in a targeted manner. The large-area element is expediently an inner surface (boundary surface) of a plant or machine part of the casting plant bordering on the material to be formed. By influencing the entire fluid volume, the material is compacted so that the dimensional stability is improved during cooling, ie there is less shrinkage of the material after solidification.

The vibration excitation can in such a way that the vibration of the inner surface is at least one tangential to the interface Has component. The tangential component allows the influence of the wall, especially the wall adhesion or wall friction decrease, resulting in a higher Velocity of the melt or paste in the area of the wall leads, so that one approaches the ideal of pure plug flow. There these transverse waves (transverse waves) are practical in a fluid can't spread they are limited to the wall area.

If, on the other hand, the vibration excitation is such takes place that the vibration of the inner surface at least one normal to the interface Longitudinal waves propagate (Longitudinal waves) inside the melt or paste.

By being both tangential and normal stimulates the wall with specific vibration frequencies, you can target both the melt interface or paste to the inner mold surface as well as acting on the inside of the melt or paste.

The vibration is advantageously excited such that at the interface surface waves be formed. Similar how the transverse waves enables also this one on the interface limited local influence on the fluid (melt or paste), causing the Wall adhesion or wall friction of the fluid can also be reduced can.

The interface touching the material to be formed can the inner wall of a transport channel for the material.

The vibration excitation can also selectively over at least one coupled to the at least one vibration source selective element. Such a selective vibration excitation is e.g. in dead areas and other areas that are difficult to access for the fluid Areas such as sharp corners, edges or filigree ramifications the mold is helpful to keep the fluid flowing and thus a complete To fill to facilitate the mold.

With the vibration excitation can with predetermined frequencies or in predetermined frequency ranges be worked. Likewise, with predetermined amplitudes or be worked in predetermined amplitude ranges. In particular can the vibration excitation by at least one on the material impact pulse. This gives you a wide frequency spectrum. To be of sufficient intensity and exposure over a longer one Period to ensure can the vibration excitation by several successive impulses e.g. pulsating.

It is particularly advantageous if in the case of pulsating forming e.g. during die casting the pulsation of the vibration excitation to the pulsation of the forming has a predetermined relationship. Appropriately run here the pulsation of the forming and the pulsation of the vibration excitation in sync with each other. Due to the pressure surges and the simultaneous vibration shocks is the fluid during the Compression "shaken up". This allows a denser structure in the solidifying material and thus achieve a better quality of the casting. The pulsation can e.g. through pulsating frequency modulation the excitation frequency and / or a pulsating amplitude modulation the excitation amplitude. According to need or acceptable Effort is used to use continuous frequency and amplitude distributions or one or more discrete frequencies or amplitudes.

Preferably takes place in the casting process according to the invention a different vibration excitation depending on the process step or Contact section. For example, locally specifically the vibration influence of the interface of the Fluids dominate when dosing into the mold, while in relatively large Areas of the mold influence the vibration in the fluid volume dominated. In relatively confined areas Areas of the mold can then again dominate the influencing of the fluid interface. Similar can also specific in time, i.e. the solidification or crystallization process temporally "accompanying" the vibration excitation adapted to the respective phase of solidification or crystallization respectively.

A casting plant inner wall with a periodically structured, for example corrugated, corrugated or ribbed surface along which the fluid flows can also be used as the vibration source. This creates periodic pulsations due to "self-excitation", which spread throughout the fluid. Different inner wall areas can also be equipped with a different periodic structure (spatial frequency). This creates a superposition of pulsations of several frequencies in the fluid, which the respective correspond to spatial frequencies of the corresponding surface structure. The periodic structuring with different spatial frequencies can also be arranged superimposed in one and the same inner wall area. For example, a coarse periodic structure (fundamental spatial frequency) can be designed for relatively low-frequency pulsations for the travel of dendritic crystal structures from tempered inner wall areas, while a fine periodic structure superimposed on it can be designed in such a way that the relatively high-frequency pulsations caused by it can influence the rheological Properties of the fluid (wall friction, shear viscosity, etc.) come into question.

As another, also based on the principle the "self-excitation" source of vibration can also hydrodynamic instabilities, such as. cyclical stalls or cyclic vortex stalls of the fluid are used, whereby cyclical pulsations also occur. This can be done in the flowing fluid towering obstacles or graded, especially asymmetrical Narrows of a flow channel be provided in the casting plant.

Another advantageous Execution of the invention Process the material during of forming and / or solidification at least in some areas Seeds of crystallization vaccinated. This way specifically influence the crystallization of the melt.

The nuclei can crystallites of Have material to be formed. This makes one in some make prevents unwanted contamination of the casting. Alternatively, the nuclei but also particles from a material different from the material to be formed exhibit. In addition to influencing crystallization targeted contamination of the cast part can also be achieved.

It is particularly advantageous if The necessities Crystallization nuclei in the melt itself e.g. on a tempered Inner wall (temperature gradient) of the casting plant or in an area high shear (shear gradient) are generated in the melt. Conveniently, used for the generation of the crystallites is a combination of high temperature gradients and high shear gradient. This can e.g. achieve by one in the area of a heavily chilled Inner wall section of the casting plant, preferably upstream of the actual mold in the metering area, a strongly sheared melt flow generated. The shear effect makes spontaneous crystallization favored in the shear gradient, on the other hand, a tearing off and shredding of dendritic Favored crystal structures, those in the temperature gradient from the tempered wall into the melt to grow. The tearing of such dendrites from the wall can be done by additional Pulsation of the Schm60 06 609el flow can be favored.

It is particularly advantageous if the melt foreign particles, especially fibers such as carbon fibers, if necessary with a modified surface, or Nanoparticles can be added. This suspension can have a volume fraction of foreign particles in the range from about 0.01% to about 80%. The theoretical upper limit of the volume fraction of the foreign particles is due to the densest packing e.g. spherical particles formed, in this borderline case a partially thin layer of the melt material just the continuous phase between the foreign particles forms. Depending on the nature of the solid particles, they can even be gel-like or colloidal fluid states getting produced. Instead of solid foreign particles, you can also liquid Foreign particles, i.e. Droplet, be present in the melt (emulsion), e.g. with immiscible Alloys is the case. By adding surface-active specific substances, which is at the interface between the droplets (discontinuous phase) and the melt (continuous phase) accumulate, the emulsified state can be stabilized and one Segregation, i.e. Phase separation, can be prevented.

The nuclei can be encapsulated crystallites or contain crystallite agglomerates, the encapsulation preferably consists of a substance that is in the crystallizable liquid or pasty Material during of reshaping and / or solidification, so that the crystallites or the crystallite agglomerates are exposed in the material to be formed and to crystallize the material when it solidifies contribute.

In a further advantageous embodiment, the material is at least temporarily impressed with an expansion flow with a reduction in the fluid pressure in the expansion area before and / or during its shaping, preferably by passing the material through at least one channel-like area with at least one before and / or during its shaping Cross-sectional narrowing transported. Alternatively or additionally, a shear flow can also be impressed on the material at least temporarily before and / or during its shaping, preferably by transporting the material through at least one channel-like region (e.g. slot or nozzle) with high shear rate before and / or during its shaping , As a further alternative or in addition, a pressure flow with an increase in the fluid pressure in the pressure region can also be at least temporarily impressed on the material before and / or during its shaping, preferably by passing the material through at least one channel-like region before and / or during its shaping transported at least one cross-sectional expansion. Due to the expansion flow, shear flow or pressure flow, agglomerates such as agglomerated foreign bodies or agglomerated crystals are deagglomerated or dendritic crystal structures are detached from a wall. As a result, the particle sizes of the foreign bodies or the crystals are made more uniform and, at the same time, the total number of such particles in the fluid is increased.

Preferably the material before and / or during its transformation, alternating stretching flows, Shear currents or Compression currents, in particular by at least one cross-sectional constriction, by at least one area with a high shear gradient (gap) or through at least an area with cross-sectional expansion. By this different "stressing" of the fluid can also various types of agglomerates largely deagglomerated in the fluid become.

If the material is a multi-phase It is fluid with at least one compressible component a compression flow or an expansion flow imprinted be a compression or expansion of the compressible component he follows.

Another advantageous Execution takes place the vibration excitation such that at least in the area of the mold before and during the Solidifies an interference pattern with anti-vibration areas and vibration node areas arises, the interference pattern preferably about the entire volume of the mold is three-dimensional. In this way, targeted enrichment or depletion certain particles occur in the areas of the antinodes, as long as the fluid has not solidified. For example, Crystallites of the fluid material or foreign particles in a metal or plastic melt or redistributed different metal atoms in an alloy and especially in certain areas are enriched or depleted. The casting can therefore similar to specific properties are imprinted on composite materials ( "Quasi-composite material").

Preferably the interference pattern is pre solidification of the fluid, e.g. by changing the relative phases multiple sources of vibration, local shifted and / or distorted. This creates a blending effect. At least segregation is largely prevented. Conveniently, care is taken that the interference pattern at least at the beginning and during the Solidify locally unchanged remains. This at least prevents the structure of the solidifying Fluids weakened in an uncontrolled manner becomes. A targeted weakening of the structure in certain areas of the cast part, however, can be desired be and is made possible by this measure. Alternatively or in addition can also the amplitude of the excitation vibrations of the multiple vibration sources while of reshaping and / or solidification are changed.

Another advantageous Execution of the invention Procedures are downstream of the excitation sub-areas in which the material is vibrated on at least one Detection range of rheological properties (flow and material properties) of the material recorded. Preferably takes place in a first detection area a first rheological detection upstream of the excitation sections Properties of the material and in a second detection area a second rheological recording downstream of the excitation sections Properties of the material. This allows an assessment of the results and thus the effectiveness of the vibration excitation by comparison the rheological properties before and after the vibration excitation in the sub-areas.

The rheological properties are recorded preferably non-intrusive, e.g. by first looking at the fluid velocity profiles using the ultrasonic Doppler method determined and in addition the pressure difference in the area of the recorded speed profile along the flow direction measures or the fluid wall shear stress with a suitable sensor. From this, important ones can then be found rheological parameters such as the flow index in the power law model of the fluid or determine the flow limit of the fluid. Conveniently, will do all of these steps during the forming and / or solidification of the material.

Alternatively or in addition can the recording of rheological properties of the material by means of a capillary rheometer and / or by means of a rotary rheometer done off-line. This represents a control for the non-intrusive performed in-line How the previous paragraph works.

Recording the rheological properties of the material can also be determined by measuring the properties of the dispersion (Speed of sound, sound absorption) of mechanical waves (detection waves) done in the material. In this way e.g. the crystallite concentration are recorded in the melt.

Conveniently used for the mechanical Another wave to record the rheological properties Frequency or other frequencies than for the mechanical waves Vibration excitation in the excitation sections. Let it through avoid confusion on the sensor (ultrasound receiver).

In exceptional cases, however, the mechanical waves (ultrasonic waves) for recording the rheological properties can have the same frequency or the same frequencies as the mechanical waves for vibration excitation in the excitation sub-areas. This allows the apparatus Effort (number of ultrasound transmitters) can be kept low.

For the determination of rheological properties of the material can affect the speed of propagation of the detection waves certain frequency can be measured. Inhomogeneities or property gradients can in the material by detecting the reflection behavior and / or diffraction behavior of the detection waves can be determined. Inhomogeneities or Property gradients in the material can also be determined by detecting the damping behavior of the detection waves can be determined. For measuring the concentration of crystallites and or crystallization nuclei in the material one leads a measurement of the ultrasound speed in the material and uses the connection with the ultrasound speed.

This is particularly advantageous Localization of crystallization fronts in the solidifying material by detecting the reflection behavior and / or diffraction behavior the ultrasonic waves in the material.

To determine the viscosity function (shear viscosity) of the material becomes a determination of the speed field transverse to the direction of transport in a range of material and a determination of the pressure differential along the direction of transport of the material in the area and / or on Edge of the area of the material performed (combination of ultrasound Doppler method and pressure difference measurement).

Alternatively, the determination of the viscosity function (Shear viscosity) of the material by determining the speed field across Direction of transport in an area of the material and a determination the shear stress along the direction of transport of the material in the area and / or at the edge of the area of the material.

• 1) Schwingungsanregung;
• 2) Impfkristallisation;
• 3) Förder-Druckdifferenz;
• 4) absoluter Druck;
• 5) Temperatur.

In a further advantageous embodiment of the method according to the invention, at least one of the following measures or physical variables is triggered, depending on the rheological properties of the fluid, at least in the excitation subregions:

• 1) vibration excitation;
• 2) seed crystallization;
• 3) delivery pressure difference;
• 4) absolute pressure;
• 5) temperature.

In a particularly preferred embodiment those in the first detection area upstream of the excitation sub-areas recorded rheological properties of the material and those in the second detection area downstream of the excitation sub-areas recorded rheological properties of the material with each other and / or compared with respective rheological reference properties, being dependent a feedback within the result of the comparison or the comparisons of a control circuit for controlling the vibration excitation in the Suggestions are made.

The object of the invention is according to the invention device moderately solved by that the one heating unit, one molding unit, one casting unit and a device having a dosing unit at least in partial areas at least one unit for generating mechanical vibrations assigned.

The unit preferably has Generation of mechanical vibrations a vibratable area on that with the crystallizable liquid or pasty material is in operative connection, in particular those in vibrations movable surface the vibration generation unit directly or indirectly to the crystallizable liquid or pasty Adjacent material. The immediate border of the vibratable area to the material the introduction of vibrations into the material in a locally defined and limited area of material, while the indirect arrangement Parts of the device vibrated (structure-borne noise), so that in the Usually a less defined and less localized introduction mechanical vibrations occur in the material.

It is expedient in the device according to the invention at least the heating unit or the casting unit or the molding unit or the dosing unit a unit for generating mechanical vibrations assigned.

The device according to the invention can at least in some areas also a unit for the introduction of crystallization nuclei be assigned to the material. This is particularly advantageous in the heating area and in the metering area of the device before the material enters the casting area and the molding area of the device, in which high pressures occur.

Furthermore, the device according to the invention at least one cross-sectional constriction in their channel-like areas or a cross-sectional expansion along the flow direction of the material and / or have a slot or a nozzle. this makes possible the generation of the expansion currents mentioned above, pressure flows or shear currents in the material.

In another version, at least a partial area of the device, but in particular of the molding unit, several spaced apart units for generating mechanical Vibrations can be assigned. This allows e.g. the further mentioned above Interference pattern or three-dimensional standing waves in the filled with material Create the mold cavity before the material solidifies.

The device according to the invention preferably has in at least one of its partial areas also has a unit for recording rheological properties of the material in it. This enables monitoring and, if necessary, control and / or regulation of the rheological properties of the material during its processing in the device according to the invention.

It is particularly advantageous if at least one of the mold halves Has ejection pins, at least one of which by a vibration generating unit can be set in mechanical vibrations. Because the ejector pins in contact with the melt anyway stand and in some cases even protrude into the melt and thus into the later solidified casting, can have a particularly good distribution of mechanical vibrational energy can be achieved in the melt.

In the device according to the invention, in particular in a die casting system, there is a sprue system between the shot unit and the mold cavity, wherein the sprue system at least a vibration generation unit is assigned with which a conditioning the melt is possible shortly before entering the mold cavity.

Further advantages, features and possible applications the invention will become apparent from the following description of a not restrictive embodiment of the invention to be understood based on a single figure.

In the figure is a cold chamber die casting machine as an illustrative example of a device according to the invention shown schematically.

In a melting pot 1 there is a crystallizable molten material, such as a light metal alloy, in particular an Al-Mg alloy. Using electrical heating elements 2 surrounding the crucible has been brought into the liquid state and is kept in this state (tempered). The melting pot 1 and the electric heating elements 2 together form the heating unit of the device according to the invention.

A cylindrical casting piston 3 is in a cylindrical casting chamber 4 slidably mounted. Together 3 . 4 they form the firing unit of the device according to the invention.

A first half of the mold 5 and a second mold half attached to it 6 together define a mold cavity 7 , The two mold halves 5 . 6 together form the molding unit of the device according to the invention.

A pneumatic pressure line 8th enables the supply of compressed air from a pneumatic pressure source 19 into the crucible chamber 10 , A riser 9 for the molten material connects the contents of the crucible to the casting chamber 4 , Depending on the size of the pneumatic pressure line 8th applied pressure is more or less much molten material in the casting chamber 4 promoted. The pneumatic pressure line 8th , the pneumatic pressure source 19 , the riser 9 and the crucible chamber 10 together form the dosing unit of the device according to the invention.

The first half of the mold 5 is with a movable platen 13 connected while the second mold half 6 with a fixed platen 14 connected is. Above that through the two mold halves 5 . 6 formed molding unit is a release agent spray element 12 ,

The pouring piston 3 the shooting unit is over a rod 18 with a hydraulic piston 15 connected in a hydraulic cylinder 16 is slidably mounted. A hydraulic pressure line 17 connects the hydraulic cylinder 16 with a hydraulic pressure source 11 ,

The cold chamber die casting machine has a plurality of vibration generating units S1-S11, as follows are briefly referred to as "unit". Such a unit can e.g. a piezoelectric element for generation mechanical vibrations in the ultrasonic range. As required can large-scale or punctual units can be used.

The units S1 and S2 are with the top and bottom of the movable first mold half 5 connected. The units S3 and S4 are similar with the top and bottom of the fixed second mold half 6 connected. The unit S5 is the casting chamber 4 assigned while the unit S6 of the riser 9 assigned. The unit S7 is with the crucible chamber 10 connected, and the unit S8 is connected to the hydraulic pressure line 17 connected. In contrast to the units S1 – S8, the temperature and pressure resistant units S9 and S10 are directly in the mold cavity with the molten material 7 in touch. Alternatively, the units S5, S6 and S7 can also be designed so that they are in direct contact with the melt.

Similar to the unit S10, the unit S9 can also be arranged directly adjacent to the melt. The ejection pins (not shown) on the movable mold half are preferably used for this 5 , In addition, you can also use the fixed mold half 6 Vibration generating units (not shown), for example also in connection with ejection pins (not shown), can be attached.

The casting chamber too 4 with the mold cavity 7 connecting gating system 20 at least one unit S11 is assigned. So the melt can shortly before it enters the mold cavity 7 be conditioned. In the case of a multichannel sprue system consisting of several parallel channels, a total of several separate units can be arranged between the individual channels. In particular, such a unit can be assigned to each channel, for example.

Operation of the cold chamber die casting machine shown takes place cyclically.

First there are the two mold halves 5 . 6 in a spaced apart position (not shown) so that the mold cavity 7 is open to the outside and a previously cast object after its solidification from the molding unit 5 . 6 could be removed. The pouring piston 3 and the hydraulic piston 15 are in their rightmost position (not shown). In this open position (not shown) the inner surfaces of the mold cavity 7 through the release agent spray element 12 sprayed with release agent.

In order to cast another object, the moving platen is moved by a movement 13 the two mold halves to the right 5 . 6 brought together so that the mold cavity 7 (except for a degassing opening, not shown) is closed. A dosed amount of the molten material is then removed from the crucible 1 via the riser 9 to the casting chamber 4 conveyed by going through the pneumatic pressure line 8th the gas pressure above the liquid surface in the crucible for a certain period of time 1 elevated.

As soon as the casting chamber 4 has reached a certain degree of filling, the hydraulic pressure source 11 activated a hydraulic pressure on the hydraulic piston 15 exercise, which then moves from right to left. About the linkage 18 and the plunger 3 is thus the one previously in the casting chamber 4 dosed melt from the casting chamber 4 in the mold cavity 7 "shot" in which it is held for a period of time until it solidifies before the molding unit 5 . 6 opened again and the cast finished object is removed.

The casting cycle is now repeated for casting another item.

The equipment according to the invention of the cold chamber die casting machine with the vibration generating units S1-S11 enables the crystallizable molten material to be influenced in various areas of the die casting machine:
With units S1, S2, S3, S4 and especially with unit S9 and possibly also with unit S10, for example, the crystallization behavior of the melt in the mold cavity can 7 are influenced by suitable vibration frequencies during their cooling. In this way, the microscopic structure and thus the material properties of the casting can be influenced.
The units S5, S6 and S10, for example, allow the flow properties of the melt in the casting chamber 4 or in the riser 9 Targeted influence by influencing the rheological properties of the melt flowing past the vibrating units S5 and S6 on the one hand and reducing the wall friction between the flowing melt and the vibrating inner wall on the other hand.

The originating from the S7 unit and via the crucible chamber 10 and the crucible 1 Vibrations transmitted to the melt are suitable, for example, for influencing the crystallization in the melt. In particular in connection with the addition of seed crystals in the melt, a targeted influencing of the melt can be achieved which is coordinated with the action generated by the units S1-S5.

The unit S8 enables, for example, the superimposition of a high-frequency ultrasonic vibration and its correspondingly high-frequency pressure fluctuations on the one hand with that from the hydraulic pressure source 11 built up pressure increase for the "shot" of the melt from the casting chamber 4 in the mold cavity 7 , This, in particular in coordination with the degassing (not shown) of the mold cavity filling with melt 7 and supported by the action of units S1, S2, S3, S4 and S9, improves the penetration of the melt even into filigree areas of the mold cavity 7 , which improves the die casting result achieved or the same result with less pressure expenditure by the hydraulic pressure source 11 can be achieved.

The unit S10 is on the molten material in the casting chamber 4 facing surface of the casting piston 3 arranged and enables conditioning of the melt in interaction with the unit S5.

The unit S11 is in the area of the sprue system 20 arranged and also enables conditioning of the melt shortly before it enters the mold cavity 7 ,

Due to the multitude of different Areas of the invention Device used vibration generating units S1-S11 can the material to be processed depending on the area in which it is located currently located, with different frequencies and / or amplitudes and each with different spatial Distribution of the vibration excitation (selective, large area) conditioned become.

1

melting pot

2

electrical heating elements

3

casting piston

4

casting chamber

5

first mold (movable)

6

second mold (firmly)

7

mold cavity

8th

pneumatic pressure line

9

riser

10

Crucible chamber

11

hydraulic pressure source

12

Release agent-spraying

13

portable platen

14

fixed platen

15

Hydraulic pistons

16

Hydraulic Cylinder

17

hydraulic pressure line

18

linkage

19

pneumatic pressure source

20

Angus system

S1-S11

Vibration generating unit

Claims (80)

Process for forming a crystallizable material in the liquid or pasty state, which is allowed to solidify after the shaping and shaping, characterized in that the material is excited to vibrate at least in some areas before and / or during the shaping and / or solidification. A method according to claim 1, characterized in that the Vibration excitation takes place in a heating or tempering area. A method according to claim 1 or 2, characterized in that the vibration excitation takes place in a degassing area. Method according to one of claims 1 to 3, characterized in that that the vibration excitation takes place in a filtration area. Method according to one of claims 1 to 4, characterized in that that the material is a molten metal, in particular at least one Melt containing aluminum or magnesium is in one Melting furnace area was produced. Method according to one of claims 1 to 4, characterized in that that the material is a polymer melt, in particular a melt comprising PET which has been melted in an extruder section. Method according to one of claims 1 to 6, characterized in that that the shaping takes place in a casting mold. Method according to one of claims 1 to 7, characterized in that that the liquid or pasty Additional material Contains particles and / or bubbles. Method according to one of claims 1 to 8, characterized in that that the vibration excitation by at least one vibration source for mechanical Vibrations occur. Method according to one of claims 1 to 9, characterized in that that the vibration excitation is extensive over at least one with the vibration source coupled large area Element is done. A method according to claim 10, characterized in that the Vibration source is a casting plant inner wall with periodically structured, e.g. is corrugated, corrugated or ribbed surface from which there are pulsations spread into the fluid as the fluid flows along it. A method according to claim 10 or 11, characterized in that the vibration source is a foundry interior wall with formations where hydrodynamic instabilities, e.g. cyclical stalls or cyclic vortex stalls of the fluid, of which cyclical pulsations spread into the fluid. A method according to claim 12, characterized in that the large-scale Element an inner surface (interface) bordering on the material to be formed Plant or machine part is. A method according to claim 13, characterized in that the Vibration excitation takes place in such a way that the vibration of the inner surface is at least one to the interface has tangential component. A method according to claim 13 or 14, characterized in that the vibration excitation takes place in such a way that the vibration the inner surface at least one to the interface has normal component. Method according to one of claims 13 to 15, characterized in that that the vibration excitation takes place in such a way that surface waves at the interface be formed. Method according to one of claims 13 to 16, characterized in that that the interface touching the material to be formed is the Inner wall of a transport channel for the material is. Method according to one of claims 1 to 9, characterized in that that the vibration excitation selectively over at least one with the at least one vibration source coupled point element he follows. Method according to one of claims 1 to 18, characterized in that that the vibration excitation with predetermined frequencies or in predetermined frequency ranges. Method according to one of claims 1 to 19, characterized in that that the vibration excitation with predetermined amplitudes or in predetermined amplitude ranges. Method according to one of claims 1 to 20, characterized in that that the vibration excitation by at least one acting on the material Shock pulse occurs. A method according to claim 21, characterized in that the Vibration excitation through several successive impulses he follows. Method according to one of claims 1 to 22, characterized in that that the vibration excitation is pulsating. A method according to claim 23, characterized in that the Forming takes place pulsating, the pulsation of the vibration excitation to the pulsation of the transformation in a predetermined relationship stands. A method according to claim 24, characterized in that the Pulsation of the transformation and the pulsation of the vibration excitation run synchronously. Method according to one of claims 23 to 25, characterized in that that the pulsation is a pulsating frequency modulation of the excitation frequency is. Method according to one of claims 23 to 26, characterized in that that the pulsation is a pulsating amplitude modulation of the excitation amplitude is. Method according to one of claims 1 to 27, characterized in that that the vibration excitation depending on the process step or system section is different. Method according to one of the preceding claims, characterized characterized in that the material during the forming and / or Solidified, at least in parts, inoculated with crystallization nuclei becomes. A method according to claim 29, characterized in that the Nuclei have crystallites of the material to be formed. A method according to claim 29, characterized in that the Nuclei particles from one of the material to be formed have different material. Method according to one of the preceding claims, characterized characterized that one for the Generation of the crystallites a combination of high temperature gradients and high shear gradient used in the material. Method according to one of the preceding claims, characterized characterized in that the melt foreign particles, especially fibers such as. Carbon fibers, possibly with a modified surface, or Nanoparticles can be added. Method according to one of claims 27 to 31, characterized in that that the nuclei encapsulated crystallites or crystallite agglomerates contain. A method according to claim 34, characterized in that the Encapsulation consists of a substance that can be crystallized in the liquid or pasty Material during of reshaping and / or solidification, so that the crystallites or the crystallite agglomerates are exposed in the material to be formed and to crystallize the material when it solidifies contribute. Method according to one of claims 33 to 35, characterized in that that the volume fraction of foreign particles in the range of about 0.01 % to about 80%. Method according to one of the preceding claims, characterized characterized in that the material before and / or during its forming at least at times an expansion flow is imprinted. A method according to claim 37, characterized in that the impress the stretching current is done by going through the material before and / or during its forming at least one channel-like area with at least one cross-sectional constriction transported. Method according to one of the preceding claims, characterized characterized in that the material before and / or during its forming at least at times a shear flow is imprinted. A method according to claim 39, characterized ge indicates that the shear flow is applied by transporting the material before and / or during its forming through at least one channel-like area (eg slot or nozzle) with a high shear gradient. Method according to one of the preceding claims, characterized characterized in that the material before and / or during its forming at least at times a pressure flow is imprinted. A method according to claim 41, characterized in that; that this impress the pressure flow is done by going through the material before and / or during its forming at least one channel-like area with at least one cross-sectional expansion transported. Method according to one of the preceding claims, characterized characterized in that the material before and / or during its forming one after the other alternating flow currents, shear flows or pressure flows, in particular by at least one cross-sectional constriction, by at least one area with a high shear gradient (gap) or through at least an area with cross-sectional expansion. Method according to one of claims 7 to 43, characterized in that that the vibration excitation takes place in such a way that at least in the range of Mold before and during of the solidification, an interference pattern with areas of the antinode and areas of the nodes of vibration arises. A method according to claim 44, characterized in that the Interference pattern over the entire volume of the mold is three-dimensional. Method according to claim 44 or 45, characterized in that that the interference pattern, e.g. by changing the relative phases multiple sources of vibration, local is shifted and / or distorted. Method according to one of claims 44 to 46, characterized in that that the interference pattern at least at the beginning and during the Solidify locally unchanged remains. Method according to one of claims 44 to 47, characterized in that that the amplitude of the excitation vibrations of the multiple vibration sources while of reshaping and / or solidification is changed. Method according to one of claims 1 to 48, characterized in that that downstream of the excitation sub-areas in which vibration excitation of the material is rheological in at least one area of coverage Properties (flow and material properties) of the material recorded become. A method according to claim 49, characterized in that in a first detection area upstream of the excitation partial areas first recording of rheological properties of the material and in a second detection area downstream of the excitation sub-areas a second record of rheological properties of the material he follows. Method according to one of claims 1 to 50, characterized in that that while of the forming and / or solidification of the material, a recording of it rheological properties. Method according to one of claims 49 to 51, characterized in that that the detection of rheological properties of the material by means of a capillary rheometer and / or by means of a rotary rheometer. Method according to one of claims 49 to 52, characterized in that that by recording rheological properties of the material Detection of the propagation properties of mechanical waves (detection waves) done in the material. A method according to claim 53, characterized in that the mechanical waves for recording the rheological properties have a different frequency or frequencies than the mechanical ones Waves for vibration excitation in the excitation sections. A method according to claim 53, characterized in that the mechanical waves for recording the rheological properties have the same frequency or frequencies as the mechanical ones Waves for vibration excitation in the excitation sections. Method according to one of claims 53 to 55, characterized in that that the mechanical detection waves are ultrasonic waves. Method according to one of claims 53 to 56, characterized in that that to determine the rheological properties of the material Speed of propagation of the detection waves of a certain frequency is measured. Method according to one of claims 53 to 57, characterized in that inhomogeneities or property gradients in the material Detecting the reflection behavior and / or diffraction behavior of the detection waves can be determined. Method according to one of claims 53 to 58, characterized in that that inhomogeneities or Property gradients in the material by detecting the damping behavior of the detection waves can be determined. Method according to one of claims 53 to 59, characterized in that that the concentration of crystallites and or nuclei in the material by measuring the ultrasonic speed in the material. Method according to one of claims 53 to 60, characterized in that that the localization of crystallization fronts in the material by detecting the reflection behavior and / or diffraction behavior the ultrasonic waves occur in the material. Method according to one of claims 49 to 61, characterized in that that to determine viscosity of the material a determination of the speed field across Direction of transport in an area of the material and a determination of the Pressure difference along the direction of transport of the material in the Area and / or performed at the edge of the area of the material Method according to one of claims 49 to 61, characterized in that that to determine viscosity of the material a determination of the speed field across Direction of transport in an area of the material and a determination of the Shear stress along the direction of transport of the material in the Area and / or performed at the edge of the area of the material. Method according to one of claims 49 to 63, characterized in that that depending on a control of the vibration excitation based on the recorded rheological properties at least in the excitation sub-areas. Method according to one of claims 49 to 64, characterized in that that depending on a control of the seed crystallization based on the recorded rheological properties at least in the excitation sub-areas. Method according to one of claims 49 to 65, characterized in that that depending on a control of the delivery pressure difference based on the recorded rheological properties at least in the excitation sub-areas. Method according to one of claims 49 to 66, characterized in that that depending on a control of the absolute rheological properties Pressure takes place at least in the excitation sub-areas. Method according to one of claims 49 to 67, characterized in that that depending on a control of the temperature based on the recorded rheological properties in the sub-areas of excitation. Method according to one of claims 64 to 68, characterized in that that in the first detection area upstream of the excitation sub-areas recorded rheological properties of the material and those in the second detection area downstream of the excitation sub-areas recorded rheological properties of the material with each other and / or compared with respective rheological reference properties be, depending feedback from the result of the comparison or the comparisons within a control loop to control the vibration excitation in the sub-areas he follows. Device for carrying out the method according to one of claims 1 to 69, which comprises: ➢ a heating unit ( 1 . 2 ) for heating crystallizable material in order to bring it into a liquid or pasty state; ➢ a molding unit ( 5 . 6 ) that have a mold cavity ( 7 ) certainly; ➢ one shot unit ( 3 . 4 ) with which the material is pressed into the molding unit ( 5 . 6 ) is pressed; ➢ a dosing unit ( 8th . 9 . 10 . 19 ) for the metered feeding of the material in the liquid or pasty state from the heating unit ( 1 . 2 ) in a casting unit ( 3 . 4 ), characterized in that at least in some areas the device is assigned at least one unit (S1-S11) for generating mechanical vibrations. Apparatus according to claim 70, characterized in that the at least one unit (S1 – S11) for generating mechanical vibrations a vibratable area has that with the crystallizable liquid or pasty material is in operative connection. Apparatus according to claim 71, characterized in that the vibratable surface the vibration generating unit (S5, S6, S7, S9, S10, S11) immediately to the crystallizable liquid or pasty Adjacent material. Apparatus according to claim 71, characterized in that the vibratable surface of the vibration generating unit (S1, S2, S3, S4, S8) indirectly bordering the crystallizable liquid or pasty material. Device according to one of claims 70 to 72, characterized in that at least the heating unit ( 1 . 2 ) or the shooting unit ( 3 . 4 ) or the molding unit ( 5 . 6 ) or the dosing unit ( 7 . 8th ) a unit (S1 - S11) for generating mechanical vibrations is assigned. Device according to one of claims 70 to 74, characterized in that that the device has a unit for at least partial areas Initiation of crystallization nuclei into the material is assigned. Device according to one of claims 70 to 75, characterized in that that they have at least one cross-sectional constriction in their channel-like areas or a cross-sectional expansion along the flow direction of the material or that it has a slot or nozzle. Device according to one of claims 70 to 76, characterized in that that the at least one partial area of the device is several from one another spaced units for generating mechanical vibrations assigned are. Device according to one of claims 70 to 77, characterized in that that they have a unit in at least one of their subareas Recording rheological properties of the material in it having. Device according to one of claims 70 to 78, characterized in that at least one of the mold halves ( 5 . 6 ) Has ejection pins, of which at least one can be set into mechanical vibrations by a vibration generation unit. Device according to one of Claims 70 to 79, in which a sprue system ( 20 ) between the firing unit ( 3 . 4 ) and the mold cavity ( 7 ) is arranged, characterized in that the sprue system ( 20 ) at least one vibration generation unit (S11) is assigned.