Device and arrangement for treating 3D-printed workpieces

Abstract

Device for treating 3D-printed workpieces (1) with a heated liquid (2), comprising: - a container (3) with a container base (4) and a container shell (5), which together define an interior space (6) for receiving the liquid (2) and the workpiece (1) to be treated, - a heating arrangement (7) for heating the liquid (2) arranged in the interior (1), - a stirring arrangement (21) for generating a movement of the liquid (2) arranged in the interior (6), characterized in that the container (3), its container base (4) and its container jacket (5) are made of plastic.

Description

The invention relates to a device and an arrangement according to the features of the independent claims.Devices for treating workpieces, in particular 3D-printed workpieces, are known and published in various designs.For example, washing stations are known which can wash off excess resin from 3D printed workpieces. The workpieces are positioned in a container in which a washing liquid is provided. In order to improve the washing function, a stirrer may be provided which moves the liquid provided in the container to thereby rinse the 3D printed workpiece with the liquid.Devices are also known which are filled with a release liquid for releasing workpieces or parts of workpieces. Thus, releasable auxiliary materials for 3D printed workpieces are known, for example auxiliary materials which serve as support material in the case of FFF printing. This support material can then be dissolved by the release liquid, so that only the actual workpiece remains.Furthermore, apparatuses for treating workpieces are known in which, for example, the surface of workpieces is changed or which are configured to color a workpiece. Such devices usually use liquids which are heated and, in addition, are often strongly acidic, i.e. have a low pH.The heating of the liquid in such devices usually takes place via a heating plate, an external heat exchanger with a circuit fed via a pump or an immersed heating coil, on which a metallic container is placed, which is then heated by the heating plate or the heating coil, so that the liquid provided in the container is also heated. Metallic containers are often susceptible to corrosion, in particular at higher temperatures and in acidic liquids, particularly if they consist of insufficiently resistant metal alloys and / or if they are not remachined by measures such as electro-polishing, coating such as enamelling or ceramic coating. Corrosion-resistant metallic containers are expensive due to the high metal quality, post-processing and / or coating. Although nonmetallic materials are known which have a very high resistance to acidic liquids, they are often not efficiently heatable. For example, a container made of polyethylene or polypropylene is acid-resistant-but the low melting point of these materials prevents the plastic container from being easily positioned on a heated heating surface. Containers made of glass or ceramic are fragile and the passage of a shaft of a stirrer and the sealing in this region is associated with very great technical complexity.Another problem with hot acidic liquids is the creation of a liquid flow within the container. For stirrers which project through the vessel shell with a driven shaft, sealed leadthroughs must be provided. However, the seals of the feedthroughs are very susceptible to acidic liquids and especially when heated. Moreover, shaft feedthroughs require regular maintenance in order to ensure tightness.Thus, in devices of the above-mentioned type, there is a conflict of goals between resistance to liquids having different pH values, heat resistance and simplicity of construction.The object of the invention is now to solve this conflict of goals.Disclosed is an apparatus for treating 3D printed workpieces with a heated liquid, comprising:a container having a container bottom and a container jacket which together define an interior space for receiving the liquid and the workpiece to be treated,preferably a heating arrangement for heating the liquid arranged in the interior space,preferably a stirring arrangement for generating a movement of the liquid arranged in the interior space.It is preferably provided that the container, in particular its container bottom and its container jacket, is / are formed from plastic.It is preferably provided that the plastic is a polymer material, in particular a thermoplastic, preferably polypropylene or polyethylene.The plastic is optionally a polypropylene with an impact-resistant finish, for example a polypropylene copolymer.The plastic is preferably solid and dimensionally stable up to at least 100° C.In addition, the plastic is preferably sufficiently acid- and / or alkali-resistant to enable workpieces to be treated with customary solvents for soluble auxiliary materials, colorants and / or detergents.It is preferably provided that the container bottom and the container jacket are formed integrally from the plastic material.It is preferably provided that the heating arrangement comprises an inductor and a susceptor, which is heated or can be heated by the induction field of the inductor, for heating the liquid arranged in the interior space.It is preferably provided that the inductor is arranged outside the container.It is preferably provided that the susceptor is arranged within the container.It is preferably provided that the induction field of the inductor heats the susceptor in a contactless manner through the container, i.e. through the container base and / or through the container jacket and optionally through the protective layer.If necessary, it is provided that the susceptor is arranged at a distance from the container base and the container shell, in particular in direct proximity to the container base, in order to avoid direct heating of the container material and thus to avoid possible damage to the container due to heat. If necessary, a heat-resistant and heat-insulating protective layer, such as a silicone mat, can be provided between the susceptor and the container.The protective layer is preferably a thin layer, for example with a thickness of 1 mm, 2 mm, 3 mm, 4 mm or 5 mm. It can be connected, for example, flat to the container and the susceptor.It is preferably provided that the susceptor is an inductively heatable metal plate mounted in or on the container base.If appropriate, it is provided that the susceptor occupies more than 10%, preferably more than 20%, of the area of the container base.If necessary, it is provided that the susceptor occupies more than 5% of the inner surface of the container, i.e. of the container base and of the container jacket.It is preferably provided that the container, in particular the container base, runs without interruption between the inductor and the susceptor.It is preferably provided that the stirring arrangement comprises at least one stirring drive and at least one stirrer driven by the stirring drive for moving the liquid arranged in the interior.It is preferably provided that the stirring drive is arranged outside the container.It is preferably provided that the stirrer is arranged in the interior, within the container.It is preferably provided that the stirrer drive is magnetically coupled to the stirrer via a magnetic coupling and drives the stirrer in a contactless manner through the container, i.e. through the container bottom and / or through the container jacket.It is preferably provided that the at least one stirrer is arranged in or on the container jacket.If appropriate, it is provided that two stirrers, or more, are provided, which are preferably provided in or on opposite regions of the container jacket and are driven by a stirring drive, in particular in each case a stirring drive.If appropriate, it is provided that two stirrers are provided, which are preferably arranged next to one another on the container jacket and are driven by a stirring drive.It is preferably provided that the container, in particular the container jacket, runs without interruption between the at least one stirrer and the at least one stirrer drive.It is preferably provided that a basket is provided for receiving the workpiece or a plurality of workpieces, and that the basket is movably mounted.It is preferably provided that the workpiece can be dipped into the liquid and raised out of the liquid by moving the basket.It is preferably provided that a heat insulation is provided, which thermally isolates or respectively insulates the container. This also serves, for example, as a touch protection for a user.It is preferably provided that the thermal insulation is an outer cladding made of a thermal insulating material, such as neoprene, chloroprene, SBR or EPDM rubber. Conventional foam materials may also be suitable.It is preferably provided that a control arrangement is provided.It is preferably provided that the control arrangement comprises an, in particular continuously variable, speed control for controlling the stirrer arrangement and in particular the rotational speed of the stirrer or the stirrer.It is preferably provided that the control arrangement comprises a temperature control for controlling the heating arrangement and in particular the temperature of the liquid arranged in the interior. The temperature control can be part of the heating arrangement.It is preferably provided that a control arrangement comprises a fill level detection for detecting the fill level of the liquid arranged in the interior of the container.It is preferably provided that the fill level detection has at least one antenna for receiving the electromagnetic radiation emanating from or excited by the susceptor.It is preferably provided that the antenna is arranged outside the container and is directed from the outside onto the susceptor.It is preferably provided that the susceptor protrudes beyond the inductor by a susceptor protrusion.It is preferably provided that the antenna is arranged next to the inductor and is directed at the susceptor protrusion.It is preferably provided that the inductor and the antenna are arranged on the container base.Preferably, it is provided that the fill level detection comprises an electrode which is grounded and which protrudes into the container at a certain level and which is configured to ground the liquid provided in the container when the fill level in the container is so high that the liquid is in contact with the electrode.It is preferably provided that the fill level detection comprises an evaluation device which analyzes the antenna signal and emits a fill level signal which provides information as to whether the liquid level of the liquid in the container is above or below the level of the electrode. The evaluation device and the antenna can be integrated in one unit.Preferably, it is provided that the evaluation device outputs the fill level signal,if the antenna signal has an amplitude in the frequency range of the inductor and thus also in the frequency range of the susceptor, which amplitude is reduced compared to the amplitude in the case of ungrounded liquid,or if the antenna signal has an amplitude in the frequency range of the inductor and thus also in the frequency range of the susceptor, which amplitude is increased compared to the amplitude when the liquid is grounded.An arrangement comprising the described device and a liquid provided in the container is disclosed.It is optionally provided that the liquid is a dissolving liquid which preferably has one or more of the following parameters or properties:pH 8 to 14, preferably 10 to 13,- alkaline,aqueous alkaline solution,alkali containing sodium carbonate, sodium hydroxide, aqueous solution of ammonia NH3 or sodium disilicate,suitable for dissolving soluble support materials of FFF-printed workpieces,Not suitable for dissolving conventional FFF model materials.It is optionally provided that the liquid is a coloring liquid which preferably has one or more of the following parameters or properties:suitable for coloring 3D-printed workpieces, in particular for coloring FFF-printed workpieces, or workpieces printed by other methods, e.g. powder printing methods, in particular multijet fusion (MJF) or selective laser sintering (SLS),pH 2 to 5, preferably 3 to 4,citric acid solutions.It is optionally provided that the liquid is a washing liquid which preferably has one or more of the following parameters or properties:suitable for cleaning workpieces,aqueous washing liquids,- Washing liquids containing detergents or soaps.The apparatus is preferably configured for the treatment of workpieces which have been produced or 3D-printed according to the FFF method.The device is preferably designed to automatically dissolve soluble support materials, to color plastic parts and to clean 3D-printed workpieces, in particular polymer parts or metal parts.The device is preferably configured to heat a liquid, in particular water, to up to 95° C.The liquid is preferably circulated by a magnetic stirring arrangement without mechanical seals or shaft sealing rings.Depending on the application, suitable cleaning or colouring additives can be used.The device preferably dissolves the auxiliary materials with the aid of heated and stirred water.In order to enable dissolution of VXL support materials, additives such as VXL EX and VXL SOLVE can be added to the water.Possible auxiliary or support materials can be, for example, polyacids, such as polymers based on acrylate polymer, co- and / or terpolymers. Suitable dissolving liquids for this purpose can be, for example, aqueous alkalis.The heating arrangement preferably uses an induction heating technology that enables a precise and energy-efficient temperature control. Compared to conventional heating systems, this solution is distinguished by faster heating times and a more uniform heat distribution.The container is preferably made of high-quality polypropylene, which ensures exceptional resistance to aggressive chemicals. This choice of material offers advantages in particular in the processing of strongly acidic dyeing solutions (pH 3 and lower), in which conventional stainless steels would corrode without corresponding post-treatment, such as V2A, for example.Despite the robust construction, the device is light in weight, which significantly facilitates shipping, installation and maintenance.A preferred feature is the two-sided stirring arrangement, which can also have a continuously variable speed control. This construction ensures optimum mixing of the liquid and promotes uniform dissolution and coloring results and a particularly efficient dissolution rate.An integrated control arrangement can have a monitoring system which automatically detects and reports potential faults in the agitator operation.The device preferably has a fill level detection, in particular a radio sensor for contactless fill level detection. This technology functions reliably even in suspensions and slurries and enables precise fill level monitoring without mechanical wear parts, without optical sensor technology, and without sensitive sensors being exposed in aggressive media. Furthermore, no radiating material is required for the measurement. In addition, no movable sensor components such as floats are required, which usually do not offer sufficient reliability, for example in sludge suspension. It is particularly insensitive to disturbances, since it does not comprise moving parts and is particularly robust with respect to the formation of deposits. Foaming material can also be detected if necessary.An integrated WLAN interface, which may be provided, enables convenient control via a dedicated app. Users can monitor and control all process parameters in real time, enabling flexible and efficient process control.The device preferably has a thermal insulation, in particular an insulation sheath made of neoprene, which can offer several advantages:flexible design for optimum matchingSimple cleaning by means of a washable materialExchangeability for long-term serviceabilityEffective protection of persons by thermal insulationoptimized energy efficiency due to excellent insulating propertieseasy assembly and disassembly, optionally without auxiliary means / tool- light weightThe possible areas of application of the device are:Support removalEfficient dissolution of soluble, in particular water-soluble, support materialsoptimized process control by precise temperature controlOptionally uniform material dissolution by the dual stirrer systemPreferably, stirrer is sufficient in the case of smaller containers (<50 litres), and a plurality of stirrers may be advantageous in the case of large containers (>100 litres)Professional dyeing processesSafe processing of strongly acidic dye solutionsuniform dyeing results by optimized mixingPrecise process control for reproducible resultsExemplary Technical Specifications of a Possible Embodiment:- External dimensions: 750 x 460 x 600 mm- Working space volume: 74 litersMaximum component size: 430 x 325 x 315 mmDead weight: 24.8 kg- Heating power: 3,500 W- Stirrer power: 90 W- Operating temperature: 40-95°CPower supply: AC 230V / 50HzMaximum volume 50 dB- Stirring speed 0 - 240 U / minA robust construction of the container made of chemical-resistant polypropylene with a simultaneously low weight enables post-processing and / or coloring of 3D-printed workpieces. The particular material resistance to aggressive media, in particular in the strongly acidic range, enables stringent requirements for process safety and longevity.Exemplary Materials of a Possible Embodiment:- Lid: polypropylene- Container: polypropyleneInner parts, such as e.g. basket, stirrer, plate of the stirring arrangement: plastic or high-quality stainless steel, e.g. V4A or duplex steel, electropolished, mordanted, passivated.Heating plate: ferromagnetic steel which is protected from corrosion, for example by painting, sandwich construction with stainless steels, enamelling, particularly high-quality duplex steels.Exemplary Auxiliary Materials, in particular FFF Support Materials:- Xioneer VXL 70- Xioneer VXL 90- Xioneer VXL 111- Xioneer VXL 130- Xioneer VXL 150- PVA / PVOH / BVOHAuxiliary materials for polyjet (R) technology such as, for example, SUP705, SUP705B, SUP711- Stratasys SR10, SR20, SR30, SR35, SR110, SR120,and similar materials.Exemplary Solvent Additives:- Xioneer VXL EX- Xioneer VXL SOLVEsodium hydroxide solutionExemplary Dye Solution:Nakama Products Rit ProLine- CN GTCand othersExemplary pH range of the liquid:dyeing: 3-7- Dissolution: 7-13Possible embodiment of the device:The device is preferably used for the automatic removal of soluble, 3D-printed support material and for dyeing plastic parts. For this purpose, water is introduced into the machine. This is heated to up to 95° C. and moved through the stirring arrangement. The supporting structure of an inserted workpiece is dissolved by the movement of the heated liquid and the plastic parts are colored. Depending on the backing material or color selection, a cleaning additive or colorant may be added. After dissolution, dyeing and / or washing, the workpiece can be removed from the container and cleaned under running water. If different liquids are used for dyeing and dissolving, these processes cannot, of course, be carried out simultaneously.The device can optionally be monitored via an app and the function of the stirrer can be controlled. In the app, for example, the speed of the stirrer can be adjusted and the current status of the heating arrangement can be viewed. The main function of the app is to provide important feedback to the user. For example, warnings are displayed when the agitator is blocked or no water is in the apparatus. In addition, the user can regulate the speed of rotation of the stirrer via the app.The control arrangement preferably monitors the heating process and uses sensors for monitoring the liquid fill level and the motor current of the stirring drive. The inductor is preferably connected to the control arrangement and can be switched off via relays if anomalies are detected.If necessary, at least one of the two, preferably both, safety functions ensures reliable operation of the device:Fill level detection: A sensor ensures that a sufficient quantity of liquid is present in the tank before the start of heating.motor current monitoring: The control arrangement continuously monitors the motor current of the stirring drive. An unusually low flow may indicate lack of liquid, while an unusually high flow indicates that the agitator assembly is blocked. In both cases, the control unit optionally switches off the induction furnace in order to prevent damage.To protect against heat damage, in all embodiments a heat-resistant and heat-insulating protective layer such as a silicone mat can be provided between the susceptor and the container.For mixing the liquid, the device preferably uses a stirring arrangement with a magnetic coupling. This design eliminates the need for openings in the container and provides a hermetically sealed environment.If appropriate, a stepping motor unit is provided for the stirring drive. On the outside of the device there is preferably a drive housing with a stepping motor. In the drive housing, for example, a plate with magnets is driven by the stepping motor. The poles of the magnets are arranged, for example, alternately.Internal propeller unit for the stirrer: Inside the container, a propeller with a corresponding magnetic arrangement is preferably aligned with the plate of the stepper motor. This magnetic coupling transfers the rotational force from the stepper motor to the propeller, so that the liquid is mixed without compromising container integrity.Disclosed is a measuring arrangement and a measuring method, in particular a fill level detection, for detecting the fill level of a liquid which is inductively heated or can be heated in the interior of a container via an inductor and a susceptor.In the disclosed apparatus, the liquid in the container is inductively heated. An electromagnetic field is thereby generated by the inductor. The electromagnetic field is preferably an alternating field with a specific alternating frequency. The AC frequency can be, for example, in the range from 10 kHz to 100 kHz, preferably of approximately 20 kHz. This field penetrates the container and heats the susceptor inside the container due to the induced eddy currents and hysteresis losses in the ferromagnetic and conductive material of the susceptor.This susceptor releases the generated heat to the liquid provided in the interior of the container.In this case, it may be important to measure the fill level.The measuring arrangement now comprises an antenna and an electrode. The electrode is preferably grounded. The electrode protrudes into the container at a certain level. This causes the liquid to be grounded as soon as it rises above this level in the container. Finally, at this level, the electrode dips into the liquid and grounds it. For this purpose, the liquid should have a certain electrical conductivity.The antenna is now configured to receive the electromagnetic radiation emanating or excited from the susceptor. For this purpose, the antenna is preferably arranged outside the container and directed from the outside onto the susceptor.According to a preferred embodiment, the susceptor projects beyond the inductor by a certain susceptor projection. The antenna is now preferably arranged next to the inductor and directed at this susceptor protrusion.The liquid is preferably disposed in the container without being grounded, i.e. electrically insulated, as long as it does not contact the electrode. If the fill level of the liquid is thus below the level of the electrode and if the susceptor is excited by the inductor with the electromagnetic field, the electromagnetic radiation is picked up by the antenna. In particular, the amplitude or the presence of a signal at the induction frequency can be detected from the antenna signal. Further components in the tank should be insulated from the ground / earth for this purpose in order to avoid unintentional earthing of the liquid.If, however, the liquid is now brought into contact with the electrode, this being effected in particular by exceeding a certain fill level of the liquid in the container, the liquid is grounded and the signal is attenuated or disappears.This change in the amplitude of the signal, in particular in the region of the induction frequency, can now be analyzed by an evaluation device. The evaluation device can subsequently output a fill level signal which provides information as to whether the fill level of the liquid in the container is above or below the level of the electrode.By means of this simple method, the fill level can be detected, particularly in the case of inductively heated liquids, solely by the provision of an antenna, an electrode and a suitable evaluation device. This concept can also be extended in principle to non-inductively heated containers. In this case, an electromagnetic transmitter and an electromagnetic receiver provided in the liquid would have to be additionally provided, wherein the transmitter replaces the inductor and the receiver replaces the susceptor.Disclosed are a method and a measuring arrangement for determining the fill level with simultaneous heating of an electrically conductive liquid in an electrically insulating container.A method and a measuring arrangement for determining the fill level in a container are proposed, which combine the functions heating and fill level detection.According to one possible embodiment, an electromagnetic field having a frequency of, for example, 20 kHz is generated by an inductor arranged under the container. This field penetrates the container bottom and heats the susceptor, in particular a metal disk in the interior of the container, which in turn gives off the heat to the liquid.At least one antenna, preferably two receiving antennas, which are mounted on the container bottom under the metal disk, and an electrode positioned at a specific level serve for fill level detection.If the liquid level is below the electrode, the liquid that is not grounded remains coupled and generates a distinct signal at both antennas. When the liquid reaches the electrode, it is grounded and the signal is extinguished or attenuated.The synergy of the induced field, two detection mechanisms and the presence or absence of the received signal allows a fill level resolution of up to 1 mm. This is influenced, for example, by the viscosity of the liquid. The lower the viscosity, the higher the accuracy may be if desired.The method and the measuring arrangement are insensitive to impurities, foam or temperature fluctuations, require minimal maintenance effort and can easily be integrated into heating and fill level control systems.The method and the measuring arrangement make it possible to combine inductive heating with a high-precision, cost-effective and simply constructed fill level measurement of a liquid in a container-and that without penetration of the container wall.The method and the measuring arrangement preferably comprise one or two parallel evaluation devices, for example a digital evaluation device based on FFT and / or an analog evaluation device based on frequency detection, in particular by means of integrated analog circuits.The at least one antenna, which is directed at the susceptor protrusion, detects the field radiated by the liquid and the susceptor. This arrangement ensures reliable detection of the presence and absence of liquid:When the container is empty, the antenna receives the signal directly from the susceptor, suggesting a lack of water.Two antennas are preferably used to increase reliability:a digital antenna having an analog-to-digital converter, digital filters (high-pass filter and low-pass filter) and an FFT analysis.an analog antenna with a completely analog signal path and a tuning filter or bandpass filter for the alternating frequency of the induction field, for example 20 kHz.In the interior of the container, an electrode is preferably installed at the monitored level, which is connected to the grounding system and grounds the liquid upon contact.The evaluation device, equipped, for example, with amplifier filters and comparators, analyzes the signals of both antennas:Liquid below the electrode: the liquid is not grounded, both antennas register a high signal level.Water touches the electrode: the liquid is grounded, both signals are suppressed.A converter processes the signals of the digital and analog antennas, if necessary:The digital signal is sent to a microcontroller via I 2 S (Inter-IC Sound).The analog signal controls, after an operational amplifier and comparator, in particular directly a relay, without the involvement of the microcontroller.The microcontroller reads out the digital signal, combines and filters the data and transmits the results to the control system and to the relay.The invention is described further below with reference to an exemplary embodiment.FIG. 1 shows a schematic sectional illustration of a possible embodiment of a device for treating 3D-printed workpieces.Unless otherwise indicated, the reference symbols correspond to the following components: workpiece 1, liquid 2, container 3, container base 4, container shell 5, interior 6, heating arrangement 7, inductor 8, susceptor 9, stirring drive 10, stirrer 11, basket 12, heat insulation 13, control arrangement 14, speed control 15, temperature control 16, antenna 17, susceptor protrusion 18, electrode 19, evaluation device 20, stirring arrangement 21, magnetic coupling 22, support material 23, cover 24, liquid level 25, protective layer 26.The device comprises a container 3. a liquid 2 is provided in the container 3, wherein the liquid forms an arrangement together with the device. An interior space 6 is provided within the container 3. The interior space 6 serves to receive the liquid 2, but also a workpiece 1.The device preferably comprises a basket 12. As a result, the workpiece 1 can be immersed in the liquid 2 and pulled out again.The container 3 preferably comprises a container base 4 and a container jacket 5. In order to close the container 3, a cover 24 is preferably provided.The container is preferably formed from a plastic, wherein the plastic is preferably a polymer material, in particular a thermoplastic, preferably polypropylene or polyethylene.The container jacket 5 can be designed in any desired manner and, for example, can extend the shape of the container bottom 4 upwards in the form of a hollow prism. In the case of a rectangular container base 4, the container jacket 5 is composed, for example, of four side walls. In the case of a round container bottom 4, a cylindrical container jacket 5 would be advantageous. If appropriate, the container shell 5 has flattened portions for various attachments such as, for example, a stirring arrangement 21.A heating arrangement 7 is provided for heating the liquid 2. The heating arrangement 7 is designed as an induction heater in the present embodiment. It comprises an inductor 8 and a susceptor 9. The inductor 8 is arranged outside the container 3 and in particular below the container base 4. The susceptor 9 is arranged inside the container 3, in particular in or on the container base 4. The inductor 8 and the susceptor 9 are preferably planar. The inductor 8 and the susceptor 9 preferably follow the course of the container 3 and in particular the course of the container base 4.In order to avoid an excessively strong, uncontrolled heating of the susceptor, liquid 2 should preferably always be located in the interior 6 of the container 3 during heating operation. This cools the heated susceptor 9 to a dimension such that no damage occurs to the container 3 or the susceptor 9. In addition, an additional protective layer 26 can prevent or reduce the direct heat transfer from the susceptor 9 to the container base 4. For safety, a fill level detection can be provided.According to the present embodiment, a stirring arrangement 21 is provided. The stirring arrangement 21 is configured to set the liquid 2 inside the container 3 in motion, in order to flush the workpiece 1 with the liquid 2.The stirring arrangement 21 comprises a stirring drive 10 for moving or rotating a stirrer 11, the stirring drive 10 preferably being arranged outside the container 3 and the stirrer 11 preferably being arranged inside the container 3. In order to avoid a drive shaft for the stirrer 11 passing through the container 3, a magnetic coupling 22 is preferably provided. This magnetic coupling 22 couples the stirrer drive 10 to the stirrer 11 in contactless fashion through the container 3. In particular, the stirring arrangement 21 is attached or provided in the region of the container jacket 5.The magnetic coupling 22 preferably comprises a plurality of magnetic elements or magnetizable elements which attract one another. As a result, a magnetic coupling can be formed in a conventional manner. In the present embodiment, a plurality of permanent magnets such as neodymium magnets are attached to a magnet rotor of the stirring drive 10. A magnetic rotor is likewise provided on the stirrer 11, but is preferably formed from an iron material, so that said magnetic rotor can be magnetically coupled to the magnetic elements. In principle, this construction can also be reversed, wherein attention must be paid to the corrosion resistance of the magnetic elements provided in the container 3.In the present embodiment, a support of the stirrer 11 is provided on a plate which is inserted into the container 3 from above, for example. This plate has a bearing for the stirrer 11 and in particular also for its components of the magnetic coupling 22.In the present embodiment, the stirrer arrangement 21 comprises two stirrers 11 and two stirrer drives 10. This allows a particularly effective flushing of the workpiece 1 with the liquid 2.In the present figure, support material 23 is provided on the workpiece 1. This is used in order to be able to form complex workpieces 1 such as bridges, for example, during an FFF printing process. The support material 23 is preferably an auxiliary material which can be dissolved or washed off by the liquid 2 so that only the workpiece 1 remains after the treatment in the device.The container 3 can be provided on its outer side with a heat insulation 13. The thermal insulation 13 can be, for example, an outer layer made of a thermal insulating material, such as, for example, a porous material and / or foamed material. According to a preferred embodiment, the thermal insulation 13 is a jacket made of neoprene.The device comprises a control arrangement 14.The control arrangement preferably comprises a speed control 15 for controlling the speed of the stirrer 11 or the stirrer 11.The control arrangement 14 preferably comprises a temperature controller 16 for controlling the temperature of the liquid 2 provided in the interior space 6.

Claims

Device for treating 3D-printed workpieces (1) with a heated liquid (2), comprising: - a container (3) having a container base (4) and a container jacket (5) which together define an interior space (6) for receiving the liquid (2) and the workpiece (1) to be treated, - a heating arrangement (7) for heating the liquid (2) arranged in the interior space (1), - a stirring arrangement (21) for generating a movement of the liquid (2) arranged in the interior space (6), characterized in that the container (3), its container base (4) and its container jacket (5) are formed from plastic.Device according to claim 1, characterised in that the plastic is a polymer material, in particular a thermoplastic, preferably polypropylene or polyethylene.Device according to claim 1 or 2, characterised in that the container base (4) and the container casing (5) are formed integrally from the plastics material.Device according to one of Claims 1 to 3, characterized in that the heating arrangement (7) comprises: - an inductor (8) - and a susceptor (9), which is heated or can be heated by the induction field of the inductor (8), for heating the liquid (2) arranged in the interior space (6).Device according to claim 4, characterised in that - the inductor (8) is arranged outside the container (3), - the susceptor (9) is arranged inside the container (3), - and the induction field of the inductor (8) heats the susceptor (9) in a contactless manner through the container (3), that is to say in particular through the container base (4) and / or through the container casing (5).Device according to claim 4 or 5, characterised in that - the susceptor (9) is an inductively heatable metal plate attached in or on the container base (4), - wherein a heat-resistant and heat-insulating protective layer (26), such as a sufficiently heat-resistant silicone mat, is optionally provided between the susceptor (9) and the container (3).Device according to one of claims 4 to 6, characterised in that - the susceptor (9) occupies more than 20% of the area of the container base (4), - and / or that the susceptor (9) occupies more than 5% of the inner surface of the container (3), that is to say of the container base (4) and of the container casing (5).Device according to one of Claims 4 to 7, characterized in that the container (3), in particular the container base (4), runs without interruption between the inductor (8) and the susceptor (9).Device according to one of Claims 1 to 8, characterized in that the stirring arrangement (21) comprises at least one stirring drive (10) and at least one stirrer (11), driven by the stirring drive (10), for moving the liquid (2) arranged in the interior.Device according to claim 9, characterised in that - the stirrer drive (10) is arranged outside the container (3), - the stirrer (11) is arranged in the interior (6) inside the container (3), - and the stirrer drive (10) is magnetically coupled to the stirrer (11) via a magnetic coupling (22) and drives the stirrer (11) in contactless manner through the container (3), i.e. through the container base (4) and / or through the container jacket (5).Device according to claim 9 or 10, characterised in that - the at least one stirrer (11) is arranged in or on the container jacket (5), - wherein optionally two or more stirrers (11) are provided, which are preferably provided in or on opposite regions of the container jacket (5) and are driven by a stirring drive (10), in particular by a stirring drive (10) in each case.Device according to one of Claims 9 to 11, characterized in that the container (3), in particular the container jacket (5), runs without interruption between the at least one stirrer (11) and the at least one stirring drive (10).Device according to one of claims 1 to 12, characterised in that a basket (12) is provided for receiving the workpiece (1), and in that the basket (12) is mounted movably, such that the workpiece (1) can be dipped into the liquid (1) and raised out of the liquid (1) by movement of the basket (12).Device according to one of Claims 1 to 13, characterized in that a thermal insulation (13) is provided which thermally isolates or respectively insulates the container (3), wherein the thermal insulation (13) is preferably an outer casing made of a thermal insulating material, such as for example neoprene, chloroprene, SBR or EPDM rubber.Device according to one of Claims 1 to 14, characterized in that a control arrangement (14) is provided.Device according to claim 15, characterised in that the control arrangement (14) comprises a continuously variable speed control (15) for controlling the stirrer arrangement (21) and in particular the speed of the stirrer (11) or the stirrer (11).Device according to claim 15 or 16, characterised in that the control arrangement (14) comprises a temperature control (16) for controlling the heating arrangement (7) and in particular the temperature of the liquid (2) arranged in the interior space (6).Device according to one of Claims 15 to 17, characterized in that a control arrangement (14) comprises a fill level detection device for detecting the fill level of the liquid (2) arranged in the interior (5) of the container (3).Device according to claim 18, characterised in that the fill level detection has at least one antenna (17) for receiving the electromagnetic radiation emanating or excited from the susceptor (9).Device according to claim 19, characterised in that the antenna (17) is arranged outside the container (3) and is directed from the outside towards the susceptor (9).Device according to claim 19 or 20, characterised in that - the susceptor (9) projects beyond the inductor (8) with a susceptor protrusion (18), - and in that the antenna (17) is arranged next to the inductor (8) and is directed towards the susceptor protrusion (18).Device according to one of Claims 19 to 21, characterized in that the inductor (8) and the antenna (17) are arranged on the container base.Device according to one of Claims 18 to 22, characterized in that the fill level detection comprises an electrode (19) which is grounded and which projects into the container (3) at a specific level, and which is configured to ground the liquid (2) provided in the container (3) when the fill level in the container (3) is so high that the liquid (2) is in contact with the electrode (19).Device according to one of Claims 19 to 23, characterized in that the fill level detection comprises an evaluation device (20) which analyzes the antenna signal and outputs a fill level signal which provides information about whether the liquid level (25) of the liquid (2) in the container (3) is above or below the level of the electrode (19).Device according to claim 24, characterised in that the evaluation device (20) outputs the fill level signal - if the antenna signal has an amplitude in the frequency range of the inductor (8) and thus also in the frequency range of the susceptor (9), which amplitude is reduced compared to the amplitude in the case of ungrounded liquid (2), - or if the antenna signal has an amplitude in the frequency range of the inductor (8) and thus also in the frequency range of the susceptor (9), which amplitude is increased compared to the amplitude in the case of grounded liquid (2).An arrangement comprising a device according to any one of the preceding claims and a liquid (2) provided in the container (3).Arrangement according to claim 26, characterised in that the liquid (2) is a dissolving liquid which preferably has one or more of the following parameters or properties: - pH 8 to 14, preferably 10 to 13, - alkaline, - aqueous alkaline solution, - alkali containing sodium carbonate, sodium hydroxide, NH3 ammonia aq or sodium metasilicate, - suitable for dissolving soluble support materials of FFF-printed workpieces, - not suitable for dissolving conventional FFF model materials.Arrangement according to claim 26 or 27, characterised in that the liquid (2) is a colouring liquid which preferably has one or more of the following parameters or properties: - suitable for colouring 3D-printed workpieces, in particular for colouring FFF-printed workpieces, - pH 2 to 5, preferably 3 to 4, - citric acid solutions.Arrangement according to one of Claims 26 to 28, characterized in that the liquid (2) is a washing liquid which preferably has one or more of the following parameters or properties: - suitable for cleaning workpieces, - aqueous washing liquids, - washing liquids comprising detergents or soaps.

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