Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
  • B22D17/20—Accessories: Details
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
  • B22D17/20—Accessories: Details
  • B22D17/2015—Means for forcing the molten metal into the die
  • B22D17/2023—Nozzles or shot sleeves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
  • B22D17/20—Accessories: Details
  • B22D17/2015—Means for forcing the molten metal into the die
  • B22D17/2038—Heating, cooling or lubricating the injection unit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
  • B22D17/20—Accessories: Details
  • B22D17/22—Dies; Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies
  • B22D17/2272—Sprue channels
  • B22D17/2281—Sprue channels closure devices therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/50—Pouring-nozzles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/50—Pouring-nozzles
  • B22D41/60—Pouring-nozzles with heating or cooling means

Definitions

• the present invention relates to a die casting nozzle and a method of operating a die casting nozzle for use in a die-cast hot-chamber system
• Metal melts with at least one melt channel in one with a
• Melting distributor connectable channel carrier wherein the melt channel merges into a heating zone and subsequently a nozzle tip, which is followed by a runner.
• the die casting nozzle is for forming a melt flow interrupting, completely reflowable plug of solidified melt in the
• the sprue as a by-product of casting which solidifies in conventional die-casting in the channels between the die-casting nozzle and the mold and the castings after demolding in ultimately undesirable manner, brings with it additional material costs, which usually between 40 and 100 percent of Weight of the casting is. Even if the sprue for material recycling is remelted, this is associated with energy and quality losses due to the formation of slag and oxide fractions. Angeless die casting avoids these disadvantages.
• Sprue are heated so that the melt remains liquid and is at best prevented at the same time at the reflux to the crucible.
• the reflux into the crucible can be prevented by valves, but also in a particularly advantageous manner by a plug of solidified melt, the
• Gate opening in the die-casting nozzle closes.
• the sprue is heated from the outside.
• the plug dissolves when heated from the wall of the Angussmund Swisss and is by the einschmanende in the next casting melt from the
• Melt temperature may be to ensure. For use in metal die casting, however, such heating elements are seldom found even in the literature.
• the abovementioned document DE 33 35 280 A1 has set itself the task of using such a heating element in the metal die casting process.
• a heating element metal core is surrounded by an insulating layer, the heating element against the metallic Au . .
• the disadvantage here is that the heating rod due to the metal core, the insulation between the heater and outer sheath and the metallic Au . .mantel itself has a high thermal inertia. This is indeed a uniform keeping warm the Melting in the die-casting nozzle possible, but not a dynamic operation in time with the casting operations. In particular, it is not possible to use the sprue area
• the die casting nozzle with high durability should have a thermal dynamics that allows operation in time with the casting operations in such a way that after each casting process, the melt in at least a portion of the die-casting at least solidifies so far that a temporary closure the nozzle takes place and an outflow or backflow of melt is prevented.
• the object of the invention is achieved by a die-casting nozzle for use in a die-cast hot-chamber chamber for molten metals with at least one melt channel in a channel carrier connectable to a melt distributor, wherein the
• Melting channel merges into a heating zone and a nozzle tip, to which a
• a melt flow interrupting plug of solidified melt can be formed, and wherein the heating zone has a preferably centrally arranged heating cartridge and / or a heated nozzle shaft and / or the nozzle tip is designed as a heated nozzle tip and at least the
• Heating cartridge, the heated nozzle shaft or the heated nozzle tip as
• Heating element is executed.
• the heating element is preferably with electrical heating executed, has a high power density in at least a partial area and low thermal inertia and is further designed in such a way that
• Temperatur Sungsgradient of 20 to 250 Kelvin per second (K / s), preferably 150 K / s, is accessible on the surface of the heating element.
• the sprue area encompasses the entire area in which the plug forms according to the invention, that is to say preferably in the area of the recess of the nozzle tip, which is preferably shaped as a truncated cone or cylinder.
• the temperature of the melt in the heating zone can drop rapidly, but without causing the melt to solidify. At the same time the temperature of the
• the heatable area for example the heating cartridge, alternatively or additionally, the heated nozzle tip, just as quickly heated again, the plug in the
• Heat energy into the melt, especially in the gate area, is made possible by the direct thermal contact between the melt and a highly dynamic heat source.
• the heat source has materials with low inertia.
• the heat required for melting is targeted and energy-saving applied to a narrow range.
• the cooling takes place in a narrow range, so that the energy loss is low and the cooling rate is high.
• the nozzle tip can be used separately and / or is made of ceramic.
• the nozzle tip is particularly heavily loaded, since there the highest
• the nozzle tip is replaceable in order to replace it as a wearing part and to ensure proper continued operation of the nozzle as a whole. Furthermore, it is advantageous, the nozzle tip of a particularly hard, wear-resistant, chemically substantially inert material such To make ceramic (even if it is not interchangeable) to ensure a long service life of the nozzle tip and thus the die-casting nozzle as a whole or the
• the die-casting nozzle has a nozzle body which encloses the channel carrier.
• the channel carrier possibly also the
• nozzle body or a channel support which consists of titanium and / or an insulator and / or at least one support ring and / or at least one
• Titanium has a low thermal conductivity and is therefore particularly suitable for the coating of diecasting nozzle.
• the insulating effect of a sheath of the channel carrier is further improved if an additional insulator is introduced between the latter and the nozzle body, which further reduces the undesirable heat dissipation.
• the die casting nozzle rests against the melt distributor only with the support rings of the nozzle body, alternatively or additionally by at least one insulating pressure piece.
• a highly limited heat transfer can only be made via the relatively small contact surfaces between the hot die-casting nozzle and the cool casting mold or the melt distributor. It has also proved to be advantageous if the melt channel a
• Channel coating has.
• Such a coating which is particularly preferably made of enamel, prevents the corrosion of the channels through the melt flowing through them.
• Other coatings are contemplated, for example based on ceramic or sputtered.
• At least one thermal sensor is provided for determining the melt temperature in the heating zone and / or the sprue zone. This is characterized in the preferred embodiment by a low inertia in the detection of the temperature measured value and can be brought into direct contact with the melt.
• the detected temperature is connected to a
• Control device alternatively, a control device supplied.
• the control device By means of the control device, at least one of the heating elements is controlled so that the Heating power is sufficient to achieve the desired melt temperature in the intended period of time.
• a thick film heater in which a metallic conductor is embedded in the ceramic or coated with glass serves as a thermal sensor.
• a thermal sensor e.g., HTCC or LTCC
• the PTC effect where the resistivity of the conductor changes with temperature.
• a particularly advantageous linear characteristic is achievable.
• An integrated into the heating, the PTC effect using thermal sensor without on the heating element with then double functionality as heating and sensor beyond additional components is therefore explicitly included.
• a thermistor the higher the temperature, the higher the temperature of the metal with the atoms vibrating strongly in the lattice.
• this effect occurs on the NTC, but there is an additional effect that counteracts this. It is a semiconductor. If all the atoms are firmly in the grid, a semiconductor is a perfect insulator. However, when heated, the compounds in the crystal break and electrons are released, causing a current flow. The faster the atoms move in the semiconductor crystal, the more often an electron becomes free.
• thermosensor In addition to a metallic conductor, a thermal sensor according to the aforementioned
• Embodiment also have a ceramic conductor and, in particular
• melt temperature which is 20 K above the
• Diecast nozzle is feasible with minimal energy use. Furthermore, the thermal load on the components of the die casting nozzle is reduced, so that wear or chemical changes can be reduced or eliminated. This prolongs the service life of the diecast nozzle, it can be dispensed with coatings of the melt-carrying areas and the die-cast nozzle is overall cheaper. Particular advantages has a die-casting, in which at least one
• Cross-section change is provided, which limits the heat flow to the sprue area. Such a cross-sectional change can in the heating zone
• melt channel can be achieved at the gate point by a spoiler lip or on the heating element.
• a cross-sectional change is preferably arranged between the heating area and the tip area, which limits the heat flow to the sprue area.
• the amount of heat that can flow over from the heating area to the peak area can be set. This makes it possible to influence at which temperature in the heating zone of the melt channel, taking into account the cooling time in the area of the nozzle tip, the melt present there solidifies. Furthermore, if the temperature in the heating zone is influenced, the temperature in the sprue area, in the tip area or in the nozzle tip can also indirectly be influenced in order to be able to control the closure of the sprue by a solidified melt plug.
• the object of the invention is further achieved by a heating element with electrical heating and with a high power density (high-performance heating element) in at least a partial region and low thermal inertia, carried out in such a way that a temperature change gradient of 20 to 250 K / s, preferably 150 K / s, is accessible on the surface of the heating element.
• the heating element is to achieve the low thermal inertia of materials with low density and high thermal conductivity, thus low heat capacity. Since the materials themselves do not store a large amount of heat, they are quickly heatable and can cool down just as quickly.
• the heating element consists in particular of the surfaces of electrically well insulating materials, so that higher voltages can be used to operate the electric heater in order to limit the current intensity and thus the cross section of the leads and the line losses.
• a heating region, a tip region, a nozzle shaft and / or a nozzle tip which are embodied at least partially as a high-performance heating element, preferably have a layer structure comprising an insulator ceramic and a heating conductor and can be contacted electrically via contacts.
• the insulator ceramic forms an electrically insulating cover at least on the outside and between heating conductors.
• Insulator ceramic are also in particular glass, enamel or frits (silicates) in question.
• the heating conductor can be electrically contacted via electrical connections (contacts).
• the heating conductor is formed in a preferred embodiment as a conductor ceramic.
• the ceramics are inexpensive, have a particularly low heat capacity and withstand the material stresses caused by temperature changes or conductor and insulator have a similar coefficient of expansion. This makes them ideal for rapid temperature changes.
• the insulator ceramic on the outer wall of the heating element is also resistant to the liquid melt and does not corrode under its influence.
• the conductor ceramic or in addition thereto, for example in a
• Insert heating conductor into the insulator ceramic For this purpose, the use of a preferably high-melting metal powder whose melting temperature is above the sintering temperature of the ceramic. Alternatively, however, it is also provided that the metal powder melts during sintering and flows in a defined manner in the insulator ceramic.
• Another alternative for the execution of the Heizeiters represents a metallic conductor, which is defined for example lithographically by means of a printing process and introduced, for example, in thick-film technology, HTCC or LTCC in the insulator ceramic.
• the definition of course and width of the metallic interconnects is preferably carried out by screen printing or by photochemical means.
• silver, a silver-palladium alloy, platinum, platinum alloys or gold pastes may be considered as metals for the printed conductors and for contacting.
• a particularly preferred embodiment has a nozzle shaft which is integrally connected to the nozzle tip.
• a particularly preferred embodiment of the one-piece nozzle shaft has separately controllable heaters at least in the region of the nozzle shaft and the nozzle tip. This allows the melt temperature in the different areas of the
• Die casting nozzle can be influenced so targeted that with minimal energy consumption optimal process dynamics can be achieved.
• the shaft can be kept at a uniform temperature just above the melting point, with one or more sensors particularly preferably the temperature monitor in this area and control the heating power accordingly.
• the heating element has an outer surface or surface coating.
• a coating allows the resistance to the attacking melt to be increased.
• Other materials for coating such as enamel or glass or frits, are provided.
• an inner insert is provided instead of the coating, in particular in the sprue area, which preferably lines the highly loaded sprue area and there reduces the effects of wear by the flowing melt with nevertheless good thermal conductivity in the interest of increased service life.
• Such an insert is preferably made of low thermal conductivity ceramic, titanium or other materials with low thermal conductivity, if it is one exclusively by a
• sprue area of the mold is characterized by only a small wall thickness. This area would be heavily burdened with a heat input through the nozzle and there would be a risk of
• thermosensor which is preferably arranged close to the sprue is used particularly advantageously, by means of which the temperature conditions in the region of the nozzle tip can be precisely detected and made the basis of a control.
• an accurate temperature control means that it is possible to dispense with coating of the areas of the diecasting die and that these can be made of steel simply and inexpensively.
• an excess temperature leading to wear and unwanted alloying between melt and nozzle material is avoided, without risking an undesirable increase in viscosity or freezing of the melt.
• the nozzle material hazardous temperatures> 450 ° C are avoided, since zinc melts even at a temperature of 390 ' ⁇ and for a quick and accurate control of this margin is already sufficient, as has been surprisingly found.
• the temperature is controlled so accurately that even at a temperature of less than 20 K above the melting temperature, a problem-free process control is possible.
• a particularly advantageous process management v.a. in the aforementioned sense, is possible with a heating cartridge, which is individually controllable in the heating area and the top area via separate electrical connections or contacts, therefore, has separately controllable heaters. This makes it possible, both in the heating zone, as well as in the tip area each have an optimal and independent
• the heating in the heating zone can be carried out continuously or at the beginning of each casting process with a lesser intensity, since the closing of the sprue area
• Schmelzzepfropfen can be melted by a targeted heating alone of the tip region and the small amount of melt present there.
• Thermosensors has proved advantageous. A particularly good fine control is possible with heaters, which were manufactured on the basis of the Dick Anlagentechnologie. Especially for a mature series product with high reproduction accuracy, the use of a single heating system is a good option.
• a heating cartridge which has an elongated shaft or a shaft extended to a head, which is guided through the melt distributor, so that the contacts are easily accessible outside of the melt distribution.
• This makes it easier to produce and check the electrical connections of the heating cartridge.
• lower requirements are placed on the heat resistance of the insulation of the supply lines, since they do not have to be led through the melt distributor, which has a high temperature which damages the insulation material. This overall improves the functional and operational safety of the diecasting nozzle.
• heating cartridge is arranged centrally or concentrically in the heating zone, so that preferably heating zone and heating cartridge have the same central axis.
• Heating area has a centering guide.
• the heating cartridge receives a particularly secure fit in the channel carrier and the central arrangement in the melt channel, in particular in the region of the heating zone is secured even under mechanical load by the einschmanende melt.
• the quality of the die-cast component is increased since the melt reaches the gate area and the casting mold with a circumferentially uniform volume flow and without temperature differences between the partial streams within the melt channels or the melt channel.
• Channel carrier fitted heating cartridge wherein the channel carrier has a seat for the heating element. against this, the heating cartridge is pressed, with a
• Expansion bolt comprising a standing with the channel carrier in a force application zone pressure screw is provided.
• the expansion bolt is in a contact zone with the heating cartridge in conjunction, so that when heating channel carrier, heating cartridge and expansion bolts, the heating cartridge is pressed by the expansion bolt against the seat.
• the force introduction zone is in the preferred
• Embodiment defined by the end of a thread in a sliding block, in which engages a pressure screw which is connected to the expansion bolt.
• the object of the invention is achieved by a method for operating a die casting nozzle with the steps operation of one or more of the heatable elements, in particular the heating cartridge, the heated nozzle shaft or the heated nozzle tip, with increased power, wherein at least in a partial area
• the melt is injected into the mold. This is followed by a reduction of the power or a shutdown of the heatable elements and a stopping of the melt stream. Finally, the heatable elements are operated with such a power, with the
• the mold is closed following the removal of the previously manufactured casting made in the previous cycle.
• the mold is closed so tightly that it withstands the high pressure of the melt.
• Gating area of the die casting nozzle by increasing the power of the heated elements.
• the increase of the power takes place from a quiescent current or, in the sense of a
• the complete switch off or the significant reduction of the heat output is particularly important if it is a method with lifting the nozzle from the mold. However, a further heating is in any case, even without a lifting of the nozzle, no longer necessary because the amount of heat contained in the melt stream ensures the maintenance of the melting temperature by the high temperature nachströmende melt.
• the melt flows through the nozzle, enters the mold until it is completely filled with melt and the melt stream comes to a standstill.
• the pressure, with which the melt was also applied when it flows into the casting mold is maintained until the melt solidifies in the casting mold. This ensures a secure filling of all cavities in the mold and avoids air pockets and other casting defects.
• the melt solidifies to the casting.
• the solidification can be accelerated in the mold by cooling channels through which a coolant flows.
• the coolant dissipates the heat of the casting.
• Solidification of the melt in the sprue area of the die casting nozzle With the solidification of the melt in the casting, which is still in direct contact with the die-casting nozzle, the heat of the melt in the sprue area of the die-cast nozzle is also dissipated into the cool casting (especially by cooling the casting mold). This leads to the solidification of the melt in this area, which also leads to the sealing of this area.
• the sprue area of the die casting nozzle is thus closed by a plug, which due to the low thermal inertia of the components Nozzle forms very quickly, so that short cycle times can be realized.
• the melt located behind the plug in the die-casting nozzle can neither flow out of it nor draw air into the die-casting nozzle and flow back into the crucible through the channels.
• the die-cast nozzle and the channels remain filled with liquid melt.
• a special case of the method according to the invention a heat flow from the nozzle tip is desired in the mold to assist their cooling with the goal of freezing the melt.
• Check valve in at least one of the melt distribution and also prevents the melt at reflux.
• melt plug melt does not escape when the mold is opened, even after the gate has been torn off the article.
• the casting can be removed from the mold, ie removed from the casting mold. This results in the easier demolition of the article in the sprue by a tear-off edge, which represents a taper and breaking point directly at the sprue.
• valve or other movable element is required to close the gate area. This would namely be exposed by the melt to high wear, because the corrosive effect of inevitably penetrating between the moving parts melt would lead to premature failure of the valve or other moving elements.
• Gating area between nozzle tip and tip area heat dissipated by the cross-sectional change in cooperation with the amount of melt located in this area and the heat flow through the gate area in the mold and the nozzle tip is determined from the outside.
• the object of the invention can be achieved in a very simple and elegant way.
• melt channel itself has a cross-sectional change.
• a further change in cross section is additionally or alternatively provided in the sprue area in the form of a spoiler edge.
• This tear-off edge also represents a thermal barrier, an area with increased thermal resistance between the die-casting nozzle and the melt, and further enables separation of the solidified melt in the die-cast nozzle from the article even before demoulding, as the melt contracts on cooling.
• the melt in the gate region between nozzle tip and tip region over the separately heated tip region tempered.
• thermosensor the temperature value of a thermosensor
• Meltetemperatur delivers to a temperature control device
• melt temperature in the heating zone and / or in the runner zone controls, so that the melt temperature is only so far above the melting temperature of the melt that a secure melt flow is guaranteed. This will be an inefficient
• the present solution in all variants provided has the advantage that no plug is formed, which can detach after melting and as such can get into the mold with the consequences mentioned. Instead, the melt can not flow back into the casting mold until it has completely melted in the area of the sprue.
• an application of the device according to the invention and of the method according to the invention is also applicable to other materials, e.g. Plastic melts with appropriate adjustment of the procedure (temperature control, temperature gradient) provided.
• Fig. 1 a a schematic sectional view of an embodiment of a
• FIG. 1 b shows a schematic sectional illustration of a further embodiment of a diecasting nozzle according to the invention with cartridge heating;
• FIG. 2 shows a schematic representation of an embodiment of a heating cartridge according to the invention in partial section;
• 3 is a schematic sectional view of an embodiment of a
• Fig. 4 is a schematic sectional view of an embodiment of a
• FIGS. 5a and 6 to 9 each show a schematic plan view of a sprue pattern of a die casting nozzle according to the invention.
• 5b shows a schematic sectional representation of a detail of an embodiment of a diecasting nozzle according to the invention for lateral gating
• FIG. 10 is a schematic sectional view of an embodiment of a
• Fig. 1 1 is a schematic sectional view of a detail of an embodiment of a diecasting nozzle according to the invention with top heating and indoor use.
• 1 a shows a schematic sectional view of an embodiment of a diecasting nozzle 1 according to the invention with a heating cartridge 2 which is contacted by electrical connections 11, a channel carrier 3 into which the melt channels 4 which are embodied in duplicate in the illustrated embodiment are introduced
• Nozzle body 5 which surrounds the channel carrier 3, and a nozzle tip 8 at the end of the die casting nozzle 1 facing towards the casting mold 22.
• the melt channels 4 extend from an eccentric inlet position of the melt from the melt distributor to a central bore in the nozzle shaft 33, the heating zone 6, and are protected in a preferred embodiment by a channel coating 20 from the adverse, especially corrosive effects of the melt.
• a steel channel carrier 3 can not alloy with the melt, nor be damaged in any other way by this.
• enamel is used in the particularly preferred embodiment.
• the melt channels 4 are formed in such a way that they can be connected to the melt distributor 21, which is only indicated in FIG. 1, and are supplied with this by the melt.
• the melt channels 4 open into the heating zone 6, which is also part of the melt channel 4 and into which the heating cartridge 2 protrudes with the heating area 17. As a result, the melt, when it is in the heating zone 6 in the nozzle shaft 33, can be heated.
• the heating cartridge 2 is also in an alternative embodiment with a
• Coating 13 provided, similar to the channel coating 20 the relevant Protects surfaces from corrosion, adhesion of melt or unwanted alloy with this. This is especially true when it is a heating cartridge 2, which is not made of ceramic.
• the die-casting nozzle 1 furthermore has a nozzle tip 8 adjoining the channel carrier 3 in the direction of the casting mold 22, which is only indicated in FIG.
• the nozzle tip 8 has in its center a to the gate point 23 towards tapering region in which the melt on the exit from the die-casting nozzle 1 on
• Gating area 10 is oriented towards.
• the nozzle tip 8 is in the preferred
• wear-resistant material such as a ceramic
• Nozzle tip 8 This ensures a particularly long service life despite the high load due to the melt emerging at high speed through the sprue area 10.
• the insulation is preferably carried out by the nozzle body 5, the heat transfer is reduced to the mold 22, since the nozzle tip 1 is supported only in the region of the support rings 7 on the mold 22.
• a further reduction of the heat transfer takes place through the use of an insulator 9 between channel carrier 3 and nozzle body 5. This can also serve air.
• the permanently secure and firm hold of the heating element 2 in the channel carrier 3 is replaced by a
• the end of the heating cartridge 2 facing towards the sprue point 23 is formed by the preferably conical tip region 18. This forms in cooperation with the inner recess of the nozzle tip 8 a hollow cone-shaped space, which is the
• Gating point 23 tapers and through which the melt must flow at high speed before it leaves the die-casting nozzle 1 through the gate 23. As soon as the melt cools in this space of the sprue area 10, it forms a tight plug, which prevents leakage or backflow of the melt and does not dissolve out of the sprue area 10 even if it starts at the beginning
• the very rapid solidification of the plug is promoted by the fact that the flowing through the narrow space in the runner 10 melt heats itself during the flow by friction itself and at an incipient cooling of the
• Tip area 18 remains flowing during the flow. On the other hand, if the melt flow stops, frictional heat no longer occurs and the melt solidifies immediately to the stopper closing the gate 10.
• the heating area 17 of the heating cartridge 2 is heated, so that the temperature of the melt in the heating zone 6 likewise increases.
• the heat is conducted on the one hand via the melt for grafting and on the other hand through the zone of the cross-sectional change 14 to the tip region 18.
• About the formation of the cross-sectional change 14 can be influenced to what extent the heat flows over to the tip region 18.
• the time of melting depending on the temperature, which reaches the heating area 17, influenced.
• 1 b shows a schematic sectional view of a further embodiment of a diecasting nozzle V according to the invention with cartridge heating by means of heating cartridge 2 '.
• the heating cartridge 2 'in this case has a head 44 which is formed cylindrically and is pressed by a expansion bolt 39 in conjunction with a pressure screw 40 against a seat 12' in a bore of the channel carrier 3.
• the pressure screw 40 generates a bias of the Dehnbolzens 39, combined with a force on the head
• cooperating elements here channel carrier 3 and expansion pin 39, also a gain of the voltage can be generated when heated. This would allow a better fit to be achieved during operation, without the fastened element, here the head 44 of the heating element 2, to flow through excessive pressure load, if the related material should tend to such an effect.
• a support ring 7 and thrust pieces 38 are provided. With these elements, the die-casting nozzle V is supported on the casting mold 22 during the casting operations, when they are during the casting
• an insulator 9 preferably an air space, is furthermore provided for this purpose.
• an insulating element for example a disk, consisting of titanium, for arrangement in the region of the end face 43 of the nozzle tip 8 is provided in order to avoid the outflow of heat directly into the gate region of the casting mold.
• a cross-sectional change 14, here in cross-section of the melt channel 4, ensures defined heat transfer via the melt into the sprue area 10 of the nozzle tip 8.
• a cross-sectional change of the heating cartridge 2, corresponding to FIG. 1a is provided.
• a further cross-sectional change in the form of the tear-off edge 42 is provided. This not only reduces the heat flow into the casting mold via the melt, but also provides a predetermined breaking point for the cooled melt at which the shrinking in the cooling, solidified melt from the article before the
• Embodiment of titanium is an inner insert, preferably made of a durable ceramic or tungsten, in the sprue 10 of advantage, since the flowing there at high speed melt would otherwise cause strong wear ß.
• the use of a thermal sensor 41 has proved to be particularly advantageous. In the preferred embodiment, this is arranged near the sprue area 10 in the nozzle tip 8, which is preferably made of insulating titanium.
• the temperature measurement that the thermosensor 41 supplies is preferably processed in a control device. This then provides a time-dependent exact temperature control in each section of the die casting process with the result of an effective use of energy and a minimum thermal load of the melt-carrying elements.
• the melt channel 4 runs from the connection area with the melt distributor deviating from the vertical through the channel carrier 3 until it hits the heating zone 6, which receives the heating cartridge 2, and continues in the heating zone 6 to the nozzle tip 8.
• the heating region 17 and the tip region 18 merge into one another without changing the cross section of the immersion heater 2.
• the inner insert 31 reduces the temperature
• Fig. 2 shows a schematic representation of an embodiment of a
• Heating element 2 in partial section, showing the heating area 17.
• a multi-layer structure of the heater can be seen, which in the particularly preferred embodiment has centrally as a core and at the periphery and for the isolation of the conductive regions from each other an insulator ceramic 15.
• the conductor ceramic 16 Embedded between these concentric layers in the embodiment shown is the conductor ceramic 16, which serves as a heater by means of its electrically conductive properties.
• the individual conductor loops are electrically insulated against each other by isolator ceramic 15.
• Cartridge 2 made of high-performance ceramics are particularly suitable for die-cast nozzles with short cycle times, which must be heated with rapidly changing heat demand.
• the ceramic heating element according to the invention in a completely different manner than in the prior art, namely in a die-cast nozzle used as a heater, where it is also driven highly dynamic using its thermal properties.
• the materials used in the preferred embodiment of the heating cartridge 2 known in the prior art ceramics are used, which are characterized by many advantages compared to metallic heating elements.
• the high surface power of up to 150 W / cm 2 and the radiation emission of e> 0.9 prove to be particularly favorable, whereby temperatures of up to 1000 ' ⁇ can be achieved, which is particularly suitable for high-melting non-ferrous metals such as aluminum, which are processed by die-casting that is of interest.
• the all-ceramic heating elements are resistant to oxidation and acids. They have a low wettability with liquid metals, high mechanical strength, good thermal conductivity and at the same time a high electrical
• Insulation resistance and high dielectric strength are characterized by high hardness and wear resistance. Due to the good and safe electrical insulation to the outside Shen the heating element 2 with higher voltages, preferably 230 V, operable. This has the advantage that a small amount of current must be conducted to the heater and the cross sections of the
• the electrically conductive ceramic and the sheath of insulating ceramic are sintered into a homogeneous body and therefore enables very high power densities with high mechanical stability.
• the good aging and wear resistance of ceramics guarantees a long service life even at high temperatures.
• alternative embodiments envisage using other materials for the heating cartridge 2, such as steel.
• a coating 13, preferably enamel, is required to produce corresponding, primarily occluding properties of the surface.
• the aim is to prevent oxidation under the influence of the aggressive melt and a low tendency of metals to adhere to the surface.
• the heating cartridge is alternatively made of a ceramic with at least one in this
• the metallic conductor is prepared as a metal powder, preferably high-melting, as a solid conductor or in a lithographic process and introduced as a film.
• the metallic conductor is prepared as a metal powder, preferably high-melting, as a solid conductor or in a lithographic process and introduced as a film.
• preferred methods are
• Thick-film technology Thick-film technology, HTCC or LTCC provided.
• a particularly preferred embodiment of the heating element 2 provides a separate heating in the heating area 17 and in the tip area 18, which can also be controlled separately via the electrical connections 1 1, 1 1 '. This can be done in particular
• the heating area 17 are continuously supplied with so much energy that the melt remains liquid.
• the tip region 18 can be heated and cooled in a targeted manner in a timed manner so that the solidification and remelting of the small amount of melt located in the vicinity of the tip region 18 is made possible.
• the cross-sectional change 14 is the
• the shaft 19, which is shown interrupted, preferably has such a great length that it protrudes upward from the melt distributor, the contacts 11, 11 'are easily accessible and cable routing through the melt distributor is avoided.
• Fig. 3 shows a schematic sectional view of an embodiment of a
• a nozzle shaft 33 is used, which is directly heated and
• a structure of insulating ceramic 15 and conductor ceramic 16 has, similar to the previously described heating element 2.
• both the nozzle shaft 33 'together with the nozzle tip 8' is made in one piece and can be heated.
• the largest part of the heating power in the area of the nozzle tip 8 ', particularly preferably in the first 1 to 15 millimeters from the starting point 23, is produced. In this case, so much heating power is entered that the heat loss in
• Front area of the nozzle is compensated. This depends on external factors like
• thermal insulation and heat-dissipating contact surfaces For example, thermal insulation and heat-dissipating contact surfaces. As a result, uniform heating of the melt takes place both via the heating cartridge 2 and via the nozzle shaft 33 '.
• the electrical connection 1 1, 1 1 ' takes place from the outside, for example via the top plate 35, where the die-casting nozzle 1 with the
• melt distributor is in contact.
• melt temperature in the range of
• Angular point 23 retains and there increases the ring diameter of the sprue 25 of FIG. 6 in such a way that the production of several parts by lateral
• an enlargement of the diameter of the heating cartridge 2 in the tip region 18 is provided.
• a solution is given the particular advantage in which the entire die casting nozzle 1 in the outer region of a nozzle body 5 has a jacket made of titanium or at least with an air layer insulating the nozzle shaft 33 'out.
• Fig. 4 shows a schematic sectional view of an embodiment of a die-casting nozzle 1 according to the invention with cartridge and tip heater.
• a nozzle shaft 33 is used, which is not heated.
• a separate nozzle tip 8 ' is provided, which by a ceramic structure
• Nozzle body 5 passed directly to the outside.
• a cheaper construction is achieved, since only in the region of the nozzle tip 8 ', where particularly high temperatures and, above all, a high dynamic between melting and solidification temperature are required, a heating ceramic is needed.
• the tip region 18 is designed to be heatable.
• Fig. 5a shows a schematic plan view of a sprue scheme of a
• Fig. 5b shows with the nozzle tip 8 "is a schematic sectional view of a detail of an embodiment of a die-casting nozzle according to the invention with lateral
• Gating 34 wherein the gate point is closed by a nozzle closure 37.
• a nozzle tip, a nozzle ring or a nozzle strip is provided depending on the specific shape of the structure of the nozzle tip 8 ", both heated and unheated variant the wall of the nozzle tip 8 "are provided as a side gate 36 for the exit of the melt in the laterally arranged sprue area of the mold, not shown.
• Fig. 6 shows a schematic plan view of a sprue scheme of a
• Such a mold is formed when, as shown for example in Fig. 1, the tip portion 18 to the gate point 23rd zoom ranges. If a larger ring diameter is required, this can be achieved by a larger diameter of the tip region 18 at the starting point 23.
• Fig. 7 shows a schematic plan view of a sprue scheme of a
• a dot shape 26 is in
• FIG. 6 25 Difference to the ring shape shown in Fig. 6 25 achieved when no tip portion 18 as shown in FIG. 1 is present and instead, as shown for example in Figure 10, the blunt heating cartridge 2 'does not reach into the nozzle tip 8 into it.
• 8 and 9 show a schematic plan view of a sprue pattern of a diecast nozzle according to the invention in flat form 27 or in a cruciform form 28.
• the basic structure of the diecast nozzle corresponds to that explained with reference to FIG. 7, namely without tip region 18 reaching far into the nozzle tip 8 the sprue 23 as a flat shape 27 results from a corresponding shaping of the nozzle tip 8.
• Particularly advantageous is a flat shape 27 for articles with a large longitudinal extent. A more uniform material outflow of the melt in four directions, however, results when using the cross shape 28th
• Fig. 10 shows a schematic sectional view of an embodiment of a die-casting nozzle 1 according to the invention with helical tube 30.
• the entire nozzle body 5 can be heated in Au -cast
• the helical tube 30 is placed around the outer shell.
• the energy attributable to the latter elements can thus lead to greater dynamics in the interest of faster casting operations and shorter cycle times according to the description of plug formation in the sprue area given at the outset.
• the thermal load of sensitive melts, especially of plastics is lower.
• FIGS. 2, 3 and 4 show a schematic sectional view of a detail of an embodiment of a diecasting nozzle according to the invention with top heating and inner insert 31, embodied as Bankkeramikdüse 32.
• a nozzle tip 8 'attached to a nozzle shaft comes with a ceramic structure as described in FIGS. 2, 3 and 4.
• the construction of insulator ceramic 15 and conductor ceramic 16 results in a high conductor density in this area, by which a high heating power can be entered into this area.
• the power density is adjustable for each region by the cross-section of the conductive regions of the conductor ceramic 16, and by appropriate doping. For exact shaping, these parts are over-turned after firing, with a layer of insulator ceramic 15 always remaining outside.
• a coating but more preferably an inner insert 31 is used here.
• This consists in particular of tungsten, but also other materials with high resistance to wear, high melting point and good thermal conductivity, such as a thermally conductive ceramic, are used.
• a closure-reducing inner liner 31 is particularly important.
• a nozzle tip 8 'made of ceramic in turn very stable, wear-resistant and not to chemical bonds or alloys tending material to dispense with the inner liner 31.
• An outer insulation is provided in preferred embodiments of both variants in order to avoid the heat flow from the die-casting nozzle.
• the wear reduction takes place additionally or alternatively to the aforementioned
• Control device only gives off the power required to melt the
• Melt grafting in the sprue area is required. This further reduces the wear of the die-cast nozzle in the sprue area.
• the control of the heating power is carried out according to the material of the melt and other parameters of the die casting nozzle, such as the gate geometry. As an alternative to a control by fixed parameters, it is provided that a control processes measured values from sensors and thus determines the heating power accordingly.
• sensors temperature sensors in the area of the diecasting nozzle, but also other sensors, such as pressure sensors in the melt channel, are provided.
• temperature sensors in the region of the melt channel on the inside and / or on its outside wall and, alternatively or in addition, pressure sensors in the interior of the melt channel 4 or in the sprue area 10 are particularly preferably used, as shown for example in FIG.
• the sprue-less die-cast hot runner system which has the diecasting nozzle according to the invention, also allows well reproducible conditions, resulting in a high, consistent casting quality.
• the wall thicknesses of the casting can be minimized with appropriate material savings by this increased quality with appropriate weight and material savings.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Ink Jet (AREA)

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• 2012
  • 2012-03-26 DE DE102012102549A patent/DE102012102549A1/de not_active Withdrawn
  • 2012-11-15 DE DE112012004748.6T patent/DE112012004748A5/de not_active Withdrawn
  • 2012-11-15 PL PL12823137T patent/PL2782692T3/pl unknown
  • 2012-11-15 US US14/357,774 patent/US9561540B2/en active Active
  • 2012-11-15 CN CN201280056239.XA patent/CN104114302B/zh active Active
  • 2012-11-15 CA CA2855799A patent/CA2855799C/en active Active
  • 2012-11-15 EP EP12823137.0A patent/EP2782692B1/de active Active
  • 2012-11-15 KR KR1020147014963A patent/KR20140109872A/ko not_active Ceased
  • 2012-11-15 ES ES12823137.0T patent/ES2546318T3/es active Active
  • 2012-11-15 WO PCT/DE2012/100349 patent/WO2013071926A2/de not_active Ceased
  • 2012-11-15 IN IN4396CHN2014 patent/IN2014CN04396A/en unknown
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