DE102008044871B4 - Vacuum casting plant, mixing head for a vacuum casting plant and method for this - Google Patents

Abstract

A method of repeatedly providing a multi-component material for use in a cycle of a vacuum casting process, comprising the step of mixing at least two components in a mixing chamber (16), wherein the mixing chamber (16) is supplied with the components in a vacuum environment, characterized in that further comprising the steps of: feeding degassed components into the mixing chamber (16) from reservoirs (13) from outside the vacuum chamber (2) in which the components are degassed for a plurality of cycles; feeding dye into the mixing chamber (16) from at least a dye reservoir (34) within the vacuum chamber (2) and mixing with the components in the mixing chamber (16) optionally and pouring the multi-component material into a mold in the vacuum environment, wherein a material flow of the components and the at least one dye to the mixing chamber via Adjustment means (24) optionally blocked or released w ird, and wherein the adjusting means (24) for the components comprise at least one rotary valve (25) with at least one passage (28) and the adjusting means (24) for the at least one dye have a needle-valve-nozzle unit, so that a fast and precise dosing of the respective material flow is possible.

Description

The invention relates to a method for providing a multi-component material for use in a vacuum casting method according to the preamble of claim 1.

Furthermore, the invention relates to a vacuum casting method with a multi-component material, in particular for a rapid prototyping method, according to the preamble of claim 3.

In addition, the invention relates to a series Vakuumgießverfahren according to the preamble of claim 5.

The invention also relates to a mixing head for mixing a plurality of (individual) components into a multi-component material, in particular for a vacuum casting installation, according to the preamble of claim 6.

Moreover, the invention relates to a vacuum casting plant, in particular a vacuum low-pressure casting plant, for producing a plastic product, in particular for rapid production of a prototype, according to the preamble of claim 19.

Vacuum casting and vacuum casting equipment are well known in the art. From the DE 28 47 504 A1 For example, a mixing head for mixing at least two flowable material components, in particular for the production of polyurethane moldings, with a mixing chamber into which at least two inlet openings (nozzles) for the material components open and in which a cleaning plunger is axially displaceable, and with a in the mixing chamber an orifice arranged throttle damper known, wherein the throttle slide is designed as a rotary valve with a passage whose free cross section increases in the direction of the outlet opening of the mixing chamber and whose cross section corresponds approximately to the cross section of the cleaning plunger in the region of the cleaning plunger facing opening of the passage.

Next is from the DE 203 13 302 U1 a mixing head for the application of multi-component reaction plastics is known, wherein the mixing head is connected to supply hoses for the pressurized components and compressed air and a handle with an operating knob or switch for compressed air valves that regulate the component flow, and further in an area in front of a Outlet nozzle a mixing chamber with a mixing coil, spiral or the like is arranged, which automatically or driven the components mixed, wherein the components are guided in separate channels or bores through a connected to the feed hoses mixing head housing, wherein the mixing head housing a valve sealing plate with holes for connects the passage of the components, wherein the valve sealing plate is followed by an outlet block with holes or channels for the components, wherein the outlet block has outlets to the mixing chamber and wherein valve tappets are present sin d, which release or close the holes of the valve sealing plate, wherein the release operation by a forward movement of the valve stem and the closing operation carried out by a backward movement of the valve lifter.

The mixing heads of the prior art are suitable for processes that are relatively tedious and expensive. Such a prior art method involves a variety of steps and requires more than about 20 minutes of time per cycle. The steps of such a process are:
Weighing two components manually, for example with several measuring cups, inserting the measuring cups with the components into a vacuum casting machine, operating a mixing stirrer to mix the components, preparing a hose system to realize a corresponding supply by means of lines, arranging the hose system with a corresponding one Funnel in a vacuum chamber of the vacuum casting machine, closing the vacuum chamber and creating a vacuum by means of vacuum pumps, maintaining the vacuum in the vacuum chamber for at least 10-15 minutes to degas the components, usually liquid resins, mixing the Components, in particular the resin components, pouring of the mixed components via the hose system and the funnel into a corresponding shape, flooding the vacuum chamber with ambient air, removing the filled mold for curing outside the vacuum chamber, cleaning the stirrer, the Schlau Chsystems and replacement of disposable tools, such as the mixing tube.

The prior art will continue to the documents DE 101 58 027 A1 . EP 0 409 656 A2 . US 2,847,196 A . US 5 529 212 A and DE 44 45 946 A1 directed.

The DE 101 58 027 A1 discloses a Vakuumgießvorrichtung for the production of castings made of plastic. The vacuum casting apparatus has a first vacuum chamber for separately venting at least two material components, a second vacuum chamber, coupled to the first vacuum chamber by means of a material passage, for receiving one or more casting molds, and a conveying device for conveying the pre-vented material components from the first vacuum chamber into the second vacuum chamber.

The EP 0 409 656 A2 discloses a device for producing castings from polymeric materials, with storage containers for the material components, measuring means for dosing the materials removed from the storage containers, mixing means for mixing the removed material components and a supply line leading to a gas-tight sealable pressure vessel in the vacuum environment filling mold is arranged.

The US 2,847,196 A discloses an apparatus for mixing and dispensing thermosetting material comprising a plastic portion and an accelerator portion, each having a reservoir for the two portions of material, metering pumps for supplying the proportions of material to a cylindrical mixing container containing a mixing feed screw for mixing the two portions of material and with a heating chamber arranged after the mixing container for curing the thermosetting material to which the mixed material components are fed by means of the mixing conveyor screw via a nozzle.

The US 5 529 212 A discloses an apparatus and method for transporting and conditioning cast resin and charging a casting plant with casting resin consisting of several components, such as resin and hardener with sedimenting fillers, the casting plant comprising a plurality of evacuatable reservoirs provided with a closable supply port, the casting resin components and the reservoirs associated metering pumps whose metering piston form a valve comprises. At a first station, the reservoir having an agitator is filled with the casting resin components, the casting resin components are mixed by means of the agitator, and then the casting resin is degassed by application of negative pressure, wherein the processing of the casting resin at a second station of the device, if necessary after a transport or storage of the reservoir takes place.

The DE 44 45 946 A1 discloses a device for metering liquid multicomponent plastics to a spout nozzle with component containers and connecting lines to a mixing head with controllable valve isolators for the individual components, in which the component containers are constructed as upright impression cylinders with a removable end cover, in each of which, via a controlled Drive is arranged movable displacer, wherein the displacer each for adjusting both the amount, as well as the percentage of components are controllable. The mixing head has a motor drive for the mixing tools and at least two valve shut-off, wherein the valve tappets are combined as valve groups and the valve shutters are small cross-section, preferably designed as a needle valve.

The present invention has for its object to provide devices and methods which in particular require less effort and allow faster casting. In particular, it is an object of the present invention to provide apparatus and methods with which series casting is possible.

These and other objects are achieved by a method of repeatedly providing a multi-component material for use in a cycle of a vacuum casting process, comprising the step of mixing at least two components in a mixing chamber, further comprising the step of: feeding degassed components into the mixing chamber from reservoirs from outside the vacuum chamber to a vacuum environment in which the components are degassed for several cycles. The reservoirs are degassed, that is acted upon by a vacuum, so that gases can escape from the components located in the reservoirs. A dosage of the components does not take place here. The dosage takes place later, for example in a mixing head. The degassing takes place in, for example, a series production once in setting up the process for a job with several prototypes to be produced.

It is provided that the components are supplied to the mixing chamber in a vacuum environment. This ensures a high quality of the components used. The mixing chamber is located, for example, in a mixing head which is in a vacuum environment, for example in a vacuum chamber. As a result, the components are not contaminated on the way from the reservoir to the mold for the prototype. In the method according to the invention is also provided that at least one dye of the mixing chamber is supplied from at least one dye container within the vacuum chamber. This is optionally mixed with the components in the vacuum chamber. In this way, different areas of a prototype to be produced can be made different in color with the components used. The feeding of the dyes is preferably carried out in the vacuum environment, for example in the mixing head. It is also provided that a material flow of the components and the at least one dye to the mixing chamber via Adjusting means is optionally blocked or released, wherein the adjusting means for the components comprise at least one rotary valve with at least one passage and the adjusting means for the at least one dye have a needle-valve-nozzle unit, so that a quick and accurate dosing of the respective material flow is possible , The multi-component material is poured into a mold placed in the vacuum environment.

In a preferred embodiment of the present invention, after each cycle, residual material of the multicomponent material is blown out by means of compressed air, wherein a blow-off medium flow via blow-off means comprising at least one rotary valve is selectively blocked or released.

The object is further achieved by a vacuum casting method with a multicomponent material, in particular for a rapid prototyping method, comprising the steps of providing the multicomponent material and pouring the multicomponent material into a mold in a vacuum environment, wherein the providing after the above method of providing according to the invention is carried out. For the production of a prototype according to a vacuum casting process, it is necessary that the components or the component mixture are degassed, for example by applying a vacuum. Pouring is also done in a vacuum environment, ensuring high quality manufacturing.

In a preferred embodiment of the present invention, it is provided that the feeding comprises the step of supplying lines of the mixing head for blowing out residual material. The blowing out can be carried out continuously or discontinuously, for example jerkily with corresponding pulse waves. For subsequent production of further prototypes, purging is required to prevent contamination. The purging may be carried out by means of a suitable purging medium, for example with air or another gas.

The object is also achieved by a series vacuum casting method, comprising a cycle comprising the steps of: storing at least two components, degassing the stored components, feeding the components into a mixing chamber, mixing the components in the mixing chamber into a multi-component vacuum-castable material and pouring the multi-component material into a mold, wherein the cycle is repeated, d. H. is performed with a first and at least one further cycle, wherein at least for a further cycle following the first cycle, the degassing step is omitted. Thereby, the degassed components are fed into the mixing chamber from reservoirs located outside the vacuum chamber and the multi-component material is poured into a mold arranged in the vacuum environment together with the mixing head. The fact that the step degassing can be omitted before supplying the components after the first cycle, at least for a part of the further cycles, can reduce the expense for the series casting process. The process is carried out in particular in a fine vacuum, that is to say at minimum suppression pressures of up to about 0.5 mbar.

The object is further achieved by a mixing head for mixing a plurality of (individual) components to a multi-component material, in particular for a vacuum casting, comprising: at least one mixing chamber for mixing the components, wherein the mixing chamber via a supply device with at least two storage containers for separate Stock of the components is connectable and the feeder are at least partially designed for operation in a vacuum environment. The mixing head can be permanently arranged and operated in a vacuum chamber. By supplying the components to the mixing chamber by means of a closed system, it is possible to degas the components once in the reservoirs and to supply the degassed components to the mixing chamber. A further step for degassing the components, for example of metered components, can thus be dispensed with. The feeder can be partially disposed outside a vacuum chamber, so that the components arranged outside the vacuum chamber can be designed differently than in the usually confined vacuum chamber arranged parts. The reservoirs are correspondingly subjected to vacuum, that is, their interior is part of the vacuum environment, which is also present in the vacuum chamber.

In one embodiment of the mixing head it is provided that the supply device comprises adjusting means for regulating and / or controlling a material flow of the components to be supplied. The adjusting means are at least partially provided on the mixing head and can be arranged with this in the vacuum chamber. The actuating means are designed for this purpose for operation in a vacuum environment. This means, for example, that the adjusting agents reliably seal off even under vacuum so that no material comes out of the mixing head undesirably.

In a further development of the mixing head is provided that the adjusting means comprise at least one rotary valve with at least one passage to the material flow to selectively lock or release. As a rotary valve is referred to in the context of the invention, a shaft through which a flow opening is opened or blocked, wherein an opening or closing takes place by a rotation of the shaft. According to the invention, the rotary valve has at least one through-opening, wherein, depending on the rotational position of the shaft, the through-channel is aligned with a flow-through opening, or the flow-through opening is blocked by the wall of the shaft. Such a rotary valve allows a fast opening and closing of passage openings for the components. Such rotary valves are permanently wear-resistant used in a vacuum environment and therefore particularly suitable.

In a further embodiment of the mixing head is provided that the actuating means further comprise a pneumatic drive for pneumatically driving the rotary valve. The pneumatic actuator preferably includes actuators, such as a lever, for actuating the shaft. By a pneumatic drive a quick and safe adjustment is possible. In addition, the fact is used that usually in a Vakuumgießanlage compressed air is present.

In yet another embodiment of the mixing head it is provided that further blow-off means are provided for removing residual material with a blow-off medium. After each cycle, residual material from conduits, channels and the like must be removed to prevent clogging by undesired hardening of the material in these elements. By blowing a fast and safe cleaning of the elements is possible.

In a development of the mixing head, it is provided that the blow-off means comprise at least one rotary valve with at least one through-channel in order to selectively block or release a blow-off medium flow. It is possible to pressurize the rotary valve in a closed state with a blow-off, in particular with compressed air, and to open the rotary valve after reaching a desired pressure for a short time, so as to realize a jerky blowout.

In a further embodiment of the mixing head is provided that further comprises a dye supply device is provided to supply a dye, in particular in a vacuum environment. Depending on the design is a dye or more dyes are fed. The dyes are preferably mixed directly in the mixing chamber with the components, so that a uniform mixing is realized.

In a further development, it is provided that the dye supply device comprises at least one vacuum-suitable dye reservoir. The dye reservoirs are arranged with the mixing head in the vacuum chamber and the dye is sealed from the environment. Even after a dye supply therefore no degassing is necessary.

In an advantageous embodiment of the invention, it is provided that the dye supply device comprises adjusting means for regulating and / or controlling a dye flow, in particular pneumatically actuable actuating means. By means of the setting means a quick and accurate dosing of dye is possible, so that dye can be selectively added to the multicomponent material in the smallest amounts.

In a further embodiment of the invention, it is provided that the adjusting means comprise at least one needle-valve-nozzle unit. By means of a needle-valve-nozzle unit designed as a needle valve system, a secure closing and dosing is possible, so that very small amounts of ink can be added.

In another embodiment of the invention, it is provided that a mixing plant with at least one mixing shaft operated via at least one mixing motor is provided for mixing the components and / or the dyes. The mixer is integrated in the mixing head or can be coupled with it, so that a compact design is possible. Preferably, the mixer is at least partially formed in a mixing tube. In particular, a spiral-shaped mixing shaft, a so-called mixing spindle, is arranged in an attachable mixing tube.

In a further embodiment of the invention it is therefore provided that the mixing chamber comprises an exchangeable mixing tube. The mixing tube can be replaced after each cycle. The mixing tube is made of plastic, for example. The replaceable mixing tube makes it possible to continue using other components. The mixing tube is placed in one embodiment on a complementary nozzle. About a corresponding attachment the mixing tube with the mixing head can be coupled.

In a further development of the invention, a clamping device for exchangeable fastening of the mixing tube to the mixing head is provided. By the clamping device a quick and easy replacement is possible, wherein the clamping device is less susceptible to contamination compared to a screw.

In a further embodiment of the invention it is provided that the clamping device comprises a gripping device, in particular a pneumatically actuated gripping device. By such a gripping device, a fast and secure fastening is possible, after a cycle, the mixing tube is released in a simple manner again.

In another embodiment of the invention it is provided that the clamping device is formed at least partially pivotable from a functional position. By pivoting or folding down the clamping device, a simple and convenient cleaning of the mixing head in a connection region, for example on an underside of the mixing head, is possible.

The object is further achieved by a Vakuumgießanlage, in particular a vacuum low-pressure casting plant, for producing a plastic product, in particular for rapid production of a prototype ("rapid prototyping"), comprising: a vacuum chamber for realizing a vacuum environment, wherein in the vacuum chamber an inventive Mixing head is arranged. In this way, a series production of prototypes within a short time by means of a system is possible.

In an advantageous embodiment of the invention, the vacuum casting further comprises reservoir for storing components, dyes and / or blow-off media. The reservoir can be arranged both outside and inside the vacuum chamber.

Preferably, the reservoirs for the components are located outside of the vacuum chamber due to their size, the reservoirs being connected to the mixing chamber via feeders to provide a closed system which is particularly vacuum-pressureable and thus creates a vacuum environment.

In an advantageous embodiment of the invention, it is provided that the storage container is coupled with conveying means for conveying the components, dyes and / or blow-off media. The conveying means preferably have metering devices for the metered delivery of components, dyes and / or blow-off media. The conveying means are, for example, pumps, in particular gear pumps or the like. By throttle bodies, valves and the like, a flow rate is adjustable.

In a further embodiment of the invention it is provided that the Vakuumgießanlage further comprises at least one control device. The control device can be designed electrically, pneumatically and / or hydraulically. By the control device, the individual components of the casting plant and / or the mixing head are controllable, for example, to achieve a certain dosage of the components and / or a dye. Further, by the control device, for example, the exhaust means and / or the clamping device can be controlled.

Further, measures improving the invention are specified in the subclaims or will become apparent from the following description of at least one embodiment of the invention, which is shown schematically in the figures. All resulting from the claims, the description or the drawing features and / or advantages, including design details, spatial arrangement and method steps may be essential to the invention both in itself and in a variety of combinations.

The figures show the following:

1 shows a perspective view of a vacuum casting machine according to the invention,

2 shows in a perspective view of a mixing head of the vacuum casting according to the invention 1 .

3 shows the mixing head in another perspective view 2 and

4 shows in perspective a clamping device of the mixing head according to the invention 2 , in two different positions.

1 shows in a perspective view of a vacuum casting according to the invention 1 , The vacuum casting machine 1 is designed as a vacuum low-pressure casting machine for producing a plastic product. This includes the vacuum casting plant 1 a vacuum chamber 2 to realize a vacuum environment. The vacuum chamber 2 is from a corresponding housing 3 surrounded by a door 4 having access to the vacuum chamber 2 can realize and with which the vacuum chamber 2 is closable to produce the vacuum environment. To get an insight into the vacuum chamber 2 with closed door 4 realize the door shown 4 a viewing window 5 on. casing 3 and door 4 with viewing window 5 are designed correspondingly stable for generating the vacuum environment. To create the vacuum environment, includes the vacuum casting machine 1 a vacuum pump 6 with which the vacuum environment can be generated. For this purpose, the vacuum pump 6 with the vacuum chamber 2 coupled to closed case 3 Air from the vacuum chamber 2 pump out. The vacuum pump 6 is in a second chamber 7 of the housing 3 arranged. The second chamber 7 is also over a door 8th closable. For moving the housing 3 this has wheels in the illustrated embodiment 9 which can be locked by means of parking brakes, so that the housing 3 Protected against a process can be switched off. On the case 3 is another case 10 arranged, which is connected to the first housing 3 can be coupled. The second housing 10 also has wheels 9 on, with which the housing 10 to proceed. On the case 10 can be further components of the vacuum casting 1 arrange for which no vacuum environment is required. As in 1 is shown on the second housing 10 a control device 11 arranged, which in this case in a control box 12 is housed. Next are on the case 10 reservoir 13 arranged for storage of components, dyes and / or blow-off media. In the illustrated embodiment, the reservoir serve 13 the stocking of components. To those in the storage containers 13 stored components, dyes, and / or blow-off the vacuum chamber 2 to feed, are the reservoir 13 with trained as metering pumps 14 coupled to convey the components, dyes and / or blow-off media. The funding 14 are again via lines (not shown here) with a mixing head 15 coupled in the vacuum chamber 2 is arranged. The mixing head 15 , which is at the heart of the vacuum casting plant 1 forms is in 2 and 3 described in more detail.

2 shows in a perspective view of the mixing head according to the invention 15 for mixing several in the storage containers 13 stockpiled individual components to a multi-component material. The mixing head 15 includes at least one mixing chamber 16 for mixing the components and optionally of additives such as dyes and the like. The mixing chamber 16 is present in a replaceable mixing tube 17 trained, with the mixing head 15 via a clamping device 18 that in the 4a and 4b is shown in more detail, connectable. The mixing chamber 16 has a mixer 19 for mixing into the mixing chamber 16 supplied components. The mixer 19 includes at least one via at least one mixing motor 20 operated mixing spindle 21 for mixing the components and / or the dyes.

To the components, dyes and / or blow-out media of the mixing chamber 16 supply, has the mixing head 16 at least one feeder 22 on. The feeder 22 includes the in 1 illustrated reservoir 13 and funding 14 and corresponding lines 23 and adjusting agents 24 for coupling the reservoir 13 with the funding 14 and the mixing chamber 16 , The lines and actuating means are partially outside the vacuum chamber 2 provided and partly in the vacuum chamber 2 , especially at the mixing head 15 , The at the mixing head 15 trained lines 23 and / or at the mixing head 15 trained adjusting means 24 for controlling and / or controlling a material flow of the components to be supplied are designed for operation in the vacuum environment. That is, the flow of material can also be controlled in the vacuum environment, without, for example, due to the vacuum material from the lines 23 or over the adjusting means 24 exit. The adjusting means 24 are at least partially as a rotary valve 25 educated. The rotary valve 25 includes one in a rotary valve housing 26 rotatable mounted rotary shaft 27 , The rotary valve housing 26 has through channels to pass through these components. The rotation shaft 27 also has passageways 28 depending on the rotational position of the rotary shaft 27 together with the passageways of the rotary valve housing 26 form a continuity line for the components or break a via line. Around the rotation shaft 27 Accordingly, to rotate and bring them in a blocking or conductive position, include the actuating means 24 a corresponding drive. The drive is also designed for a vacuum operation and preferably as a pneumatic drive 29 for pneumatically driving the rotary valve 25 educated. The pneumatic drive 29 includes for this purpose a pneumatic cylinder 30 , Preferably a double-acting pneumatic cylinder, depending on the pressurization of a piston 31 which has an appropriate mechanism 32 a rotation of the rotary shaft 27 causes. The pressurization is controlled by corresponding lines 23 ,

Over the lines 23 and adjusting agents 24 become the components of the mixing chamber 16 fed. From there, the components are mixed in a mold in the vacuum environment where they give rise to cure and finished prototypes. In order to produce another prototype after creation, the corresponding lines must 23 and adjusting agents 24 be cleaned of any residues of residual material. This includes the mixing head 15 Blow-out means, with which residual material with a blow-out, through the lines 23 and adjusting agents 24 is passed under pressure, is removed. The blow-off means can also be designed for operation under the vacuum environment. For this purpose, lines and adjusting means, which are covered by the blow-off, train accordingly. For example, the actuating means of the exhaust means are rotary valves with a correspondingly via a rotary shaft lockable passageway formed to selectively block or release a Ausblasmediumfluss.

In order to realize colored areas on the prototype, the mixing head has 15 further a Farbstoffzuführeinrichtung 33 in order to supply one or more dyes, in the present case two different dyes can be supplied. In the illustrated embodiment, the dye supply device 33 arranged in the vacuum environment. The Farbstoffzuführeinrichtung 33 comprises at least one vacuum-suitable dye reservoir 34 , in particular a dye reservoir 34 per dye. The dye can be via lines 23 and adjusting agents 24 feed the material components, for example in the mixing chamber 16 or in front of the mixing chamber 16 , The adjusting means 24 include appropriate valves for operation in the vacuum environment 35 , which in the embodiment according to 2 are designed as needle valves. The needle valves are according to 2 designed as pneumatically actuated needle valves. About the controller 11 the dosage of the dye can be controlled.

3 shows in another perspective view of the mixing head 15 to 2 , In 3 can the ink feed over the two dye reservoir 34 and the wires 23 and adjusting agents 24 to recognize the material supply. Next is in 3 the mixer 19 clearly. The mixing motor 20 is connected via a shaft with a corresponding hooking device. At this hooking the mixing spindle 21 in the mixing tube 17 hooked so that the mixing spindle 21 in the mixing tube 17 is drivable. The mixing tube 17 is stationary with the mixing head 15 connectable. To the mixing tube 17 stationary with the mixing head 15 to connect is the clamp 18 provided, which in the 4a and 4b is described in more detail.

4a and 4b show in perspective a clamping device according to the invention 18 of the mixing head 15 to 2 , in two different positions. 4a shows the clamping device 18 in a first position, in which a mixing tube 17 at the mixing head 15 attachable, wherein the mixing head 15 Here, for the sake of clarity, only the mixing head 15 largely comprehensive coverage is shown. In 4b is the clamping device 18 shown in a second position, in which a cleaning of the mixing head 15 is possible. The clamping device 18 includes a gripping device 36 that have a joint 37 at the mixing head 15 is hinged. The gripping device 36 includes two gripping arms 38 which are arranged together movable and apart from each other, so that this controls the mixing tube 17 grab and let go again. The gripping arms are preferred 38 pneumatically controlled. Through the joint 37 can the gripping arms 38 from the mixing head 15 be moved away, for example by pivoting, as in the 4b shown. In the pivoted position after 4b is the hooking device 39 of the mixer 19 visible to which the replaceable mixing spindle 21 can couple, so that the mixing spindle 21 in the mixing tube 17 over the mixing motor 20 is drivable.

• 1. Die Vakuumkammer 2 mit Vakuumpumpe 6 und einer Aufnahme für den Mischkopf 15 in der Vakuumkammer 2.
• 2. Den Mischkopf 15, der erstmals in einer Vakuumumgebung arbeitet und alle prozessrelevanten Funktionen automatisiert und optimal in sich vereinigt.
• 3. Die Zuführeinrichtung 22 zur Materialbereitstellung und Dosierung mittels der Vorratsbehälter mit einem Rührwerk und vorzugsweise elektronisch gesteuerten Zahnradpumpen für sehr variable Mischungsverhältnisse.
• 4. Die pneumatische, elektrische und/oder elektronische Steuerungseinrichtung 11, mit der alle Prozessschritte optimal gesteuert werden können.

In summary, the following can be stated:

The present invention provides an integrated overall system for producing prototypes, which contains all the required system components and optimally tunes them to the goal of process-reliable production, in particular for (small) series production. The overall system of the vacuum casting machine 1 contains the following main components:

• 1. The vacuum chamber 2 with vacuum pump 6 and a recording for the mixing head 15 in the vacuum chamber 2 ,
• 2. The mixing head 15 , who works in a vacuum environment for the first time, automating and optimally integrating all process-relevant functions.
• 3. The feeder 22 for material supply and metering by means of the reservoir with an agitator and preferably electronically controlled gear pumps for very variable mixing ratios.
• 4. The pneumatic, electrical and / or electronic control device 11 with which all process steps can be optimally controlled.

• 1. Der Mischkopf 15 arbeitet in der Vakuumumgebung, das heißt, der Mischkopf 15 arbeitet direkt im Fein-Vakuum in der geschlossenen Vakuumkammer 2. Dies wird dadurch möglich, dass die Konstruktion der Vakuumgießanlage 1, insbesondere der Ventile für Material und Blasluft, so ausgelegt ist, dass sie einem dauerhaft anstehenden Vakuum standhalten, und diese so sicher verhindern, dass Material, Farb- oder Luftspuren unkontrolliert austreten.
• 2. Automatische Materialzuführung: Der Materialfluss der bevorzugt zwei Komponenten, der von den Zahnradpumpen als Niederdruck ansteht, wird vorzugsweise mittels einer drehbaren Ventilwelle blockiert und sehr schnell über einen Hebel freigegeben, der von einem Pneumatikzylinder betätigt wird. Dies verhindert sicher das Verkleben der Ventilteile die Komponenten oder dessen unkontrolliertes Austreten.
• 3. Automatische Ausblasvorrichtung: Alle harzführenden Kanäle und Leitungen müssen nach jedem Zyklus von den in den Leitungen verbleibenden restlichen Harzmengen befreit werden. Ansonsten würden Restharzmengen beim nächsten Produkt Fehler verursachen und die Komponenten führenden Kanäle durch Aushärten verstopfen. Durch Beaufschlagen einer zweiten Ventilwelle mit Druckluft und schnellem Öffnen des Ventils wird in einem vorteilhaften Ausführungsbeispiel alles Restharz ruckartig aus dem System entfernt.
• 4. Automatische Farbzuführung: Der dargestellte Mischkopf 15 enthält eine integrierte und automatische Farbzuführung. Zwei (oder mehr) verschiedene Farben werden in kleinen Behältern 34 am Mischkopf 15 bereitgestellt, die durch Druckluft beaufschlagt sind. Durch Nadelverschlussdüsen wird verhindert, dass Rest-Farbmengen ungewollt in das Gießharz gelangen können. Durch pneumatisches Öffnen der Nadelverschlussdüsen können gezielt kleinste Farbmengen dem Materialfluss zudosiert werden; entweder aus nur einem Farbbehälter oder sogar aus beiden gleichzeitig.
• 5. Automatisches Mischwerk: Ebenfalls im dargestellten Mischkopf 15 integriert ist ein Mischwerk 19 mit Mischmotor 20 und Mischspindel 21, das die Vermischung der beiden Harz-Komponenten zusammen mit den zudosierten Farben optimal ermöglicht.
• 6. Automatische Mischrohrklemmung: Das auswechselbare Kunststoff-Mischrohr muss nach jedem Zyklus gewechselt werden. Dabei kann eine Überwurfmutter verwendet werden, welche jedoch zu Verklebung und Verschmutzung neigt.

In particular, the mixing head 15 includes a wealth of features. The integrated mixhead functions are listed below:

• 1. The mixing head 15 works in the vacuum environment, that is, the mixing head 15 works directly in the fine vacuum in the closed vacuum chamber 2 , This is made possible by the construction of the vacuum casting machine 1 , in particular the valves for material and blown air, is designed so that they withstand a permanently existing vacuum, and thus reliably prevent material, color or air traces from escaping uncontrollably.
• 2. Automatic material supply: The material flow of the preferred two components, which is pending by the gear pumps as low pressure, is preferably blocked by a rotatable valve shaft and released very quickly via a lever which is actuated by a pneumatic cylinder. This safely prevents the sticking of the valve parts to the components or its uncontrolled leakage.
• 3. Automatic blow-off device: All resin-carrying channels and lines must be freed of the remaining quantities of resin left in the lines after each cycle. Otherwise residual resin levels would cause errors in the next product and clog the component-carrying channels by curing. By applying a second valve shaft with compressed air and rapid opening of the valve, in an advantageous embodiment, all the residual resin is removed from the system in a jerky manner.
• 4. Automatic ink feed: The mixing head shown 15 contains an integrated and automatic ink feeder. Two (or more) different colors are in small containers 34 at the mixing head 15 provided, which are acted upon by compressed air. The use of needle valve nozzles prevents unwanted residues from entering the casting resin. By pneumatically opening the needle valve nozzles, the smallest amounts of ink can be added to the material flow; either from just one paint container or even from both at the same time.
• 5. Automatic mixing unit: Also in the illustrated mixing head 15 integrated is a mixer 19 with mixed motor 20 and mixing spindle 21 , which optimally enables the mixing of the two resin components together with the dosed colors.
• 6. Automatic mixing tube clamping: The exchangeable plastic mixing tube must be changed after each cycle. In this case, a union nut can be used, which, however, tends to sticking and dirt.

Preferably, a pneumatic clamping device 18 used the mixing tube absolutely close to a mixing tube nozzle of the mixing head 15 stops and releases after the end of the cycle. The entire clamping device 18 is hinged in the illustrated embodiment for better cleaning a mixing head bottom.

Due to this highly integrated design of the mixing head 15 The entire casting process can be completely safely managed by the pneumatic, electrical and / or electronic control. Manual intervention during the vacuum phase is no longer required. The number of operations per cycle is thereby reduced to only six steps and the cycle time is in the range of a few minutes, in particular in the range of less than 10 minutes, preferably less than about 9 minutes, more preferably less than 8 minutes and most preferably in the range of about 6 min.

Claims (22)

A method of repeatedly providing a multi-component material for use in a cycle of a vacuum casting process, comprising the step of: mixing at least two components in a mixing chamber ( 16 ), wherein the mixing chamber ( 16 ) the components are supplied in a vacuum environment, characterized in that they further comprise the steps of: feeding degassed components into the mixing chamber ( 16 ) from storage containers ( 13 ) from outside the vacuum chamber ( 2 ) in which the components are stored degassed for several cycles, supplying dye into the mixing chamber ( 16 ) from at least one dye reservoir ( 34 ) within the vacuum chamber ( 2 ) and mixing with the components in the mixing chamber ( 16 ) optionally and pouring the multi-component material into a mold in the vacuum environment, wherein a flow of material of the components and the at least one dye to the mixing chamber via adjusting means ( 24 ) is selectively locked or released, and wherein the actuating means ( 24 ) for the components at least one rotary valve ( 25 ) with at least one through-channel ( 28 ) and the adjusting means ( 24 ) have for the at least one dye a needle-valve-nozzle unit, so that a quick and accurate dosing of the respective material flow is possible. A method according to claim 1, characterized in that after each cycle residual material of the multi-component material is blown out by means of compressed air, wherein a Ausblasmediumfluss about blow-off the at least one rotary valve ( 25 ), optionally locked or released. A vacuum casting method comprising a multi-component material, in particular for a rapid prototyping method, comprising the steps of: providing the multi-component material and pouring the multi-component material into a mold in a vacuum environment, characterized in that providing according to a method according to any one of previous claims 1 or 2 is performed. A vacuum casting method according to claim 3, characterized in that the feeding comprises the step of: applying lines ( 23 ) of a mixing head ( 15 ) for blowing out residual material. A series vacuum casting process, comprising a cycle comprising the steps of storing at least two components, Degassing the stored components, feeding the components into a mixing chamber ( 16 ), wherein the mixing chamber ( 16 ) the components are supplied in a vacuum environment, and mixing the components in the mixing chamber ( 16 ) to a vacuum-castable multicomponent material, characterized in that the cycle is performed a plurality of times, with a first and at least one further cycle according to a method according to one of the preceding claims 1 or 2, wherein the degassing step is omitted for at least one of the further cycles in which the feeding of degassed components into the mixing chamber ( 16 ) from storage containers ( 13 ) from outside the vacuum chamber ( 2 ), and the step of pouring the multi-component material into a mold in the vacuum environment is included. Mixing head ( 15 ) for mixing a plurality of (individual) components into a multi-component material, in particular for a vacuum casting machine ( 1 ), in particular according to a method according to one of the preceding claims 1 or 2 and / or according to a vacuum casting method according to one of the preceding claims 3 or 4 and / or according to a serial vacuum casting method according to claim 5, comprising: at least one mixing chamber ( 16 ) for mixing the components, wherein the components are supplied to the mixing chamber in a vacuum environment, at least one feed device ( 22 ) for feeding the components to the mixing chamber ( 16 ), characterized in that the mixing head ( 15 ) Cables ( 23 ) and / or adjusting means ( 24 ) for controlling and / or controlling a material flow of the components to be supplied, which are at least partially designed for operation in a vacuum environment, the components being made of storage containers ( 13 ) from outside a vacuum chamber ( 2 ) and further blow-off means are provided for removing residual material with a blow-off medium. Mixing head ( 15 ) according to claim 6, characterized in that the adjusting means ( 24 ) at least one rotary valve ( 25 ) with at least one through-channel ( 28 ) to selectively lock or release the flow of material. Mixing head ( 15 ) according to claim 6 or 7, characterized in that the adjusting means ( 24 ) continue a pneumatic drive ( 29 ) for pneumatically driving the rotary valve ( 25 ). Mixing head ( 15 ) according to one of claims 6 to 8, characterized in that the exhaust means at least one rotary valve ( 25 ) with at least one through-channel ( 28 ) to selectively block or release a purging medium flow. Mixing head ( 15 ) according to any one of claims 6 to 9, characterized in that further comprises a Farbstoffzuführeinrichtung ( 33 ) is provided to supply a dye, especially in a vacuum environment. Mixing head ( 15 ) according to one of claims 5 to 10, characterized in that the dye supply device ( 33 ) at least one vacuum-suitable dye reservoir ( 34 ). Mixing head ( 15 ) according to one of claims 6 to 11, characterized in that the dye supply device ( 33 ) Adjusting means ( 24 ) for controlling and / or controlling a dye flow, in particular pneumatically actuable actuating means ( 24 ). Mixing head ( 15 ) according to claim 12, characterized in that the adjusting means ( 24 ) at least one needle-valve-nozzle unit ( 35 ). Mixing head ( 15 ) according to one of claims 6 to 13, characterized in that a mixing plant ( 19 ) with at least one via at least one mixing motor ( 20 ) operable mixing spindle ( 21 ) is provided for mixing the components and / or the dyes. Mixing head ( 15 ) according to one of claims 6 to 14, characterized in that the mixing chamber ( 16 ) an exchangeable mixing tube ( 17 ). Mixing head ( 15 ) according to one of claims 6 to 15, characterized in that a clamping device ( 18 ) for exchangeable fastening of the mixing tube ( 17 ) on the mixing head ( 15 ) is provided. Mixing head ( 15 ) according to one of claims 6 to 16, characterized in that the clamping device ( 18 ) a gripping device ( 36 ), in particular a pneumatically actuable gripping device ( 36 ). Mixing head ( 15 ) according to one of claims 6 to 17, characterized in that the clamping device ( 18 ) Is at least partially formed pivotable from a functional position. Vacuum casting plant ( 1 ), in particular a vacuum low-pressure casting plant, for producing a plastic product, in particular for rapidly producing a prototype, comprising a vacuum chamber ( 2 ) for realizing a vacuum environment, characterized in that in the vacuum chamber ( 2 ) a mixing head ( 15 ) is arranged according to one of claims 6 to 18. Vacuum casting plant ( 1 ) according to claim 19, characterized in that the vacuum casting plant ( 1 ) further reservoir ( 13 ) for storing components, dyes, and / or blow-off media. Vacuum casting plant ( 1 ) according to claim 19 or 20, characterized in that the storage containers ( 13 ) with funding ( 14 ) is coupled to convey the components, dyes and / or blow-off media. Vacuum casting plant ( 1 ) according to one of claims 19 to 21, characterized in that the vacuum casting plant ( 1 ) at least one control device ( 11 ).

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