METHOD AND DEVICE FOR MANUFACTURING A WORKPIECE

Description

[0001] The invention relates to a manufacturing method in which a workpiece is gradually built up layer by layer. To build up the workpiece, a preformed layer, which is formed on a layer carrier by means of an electrophotographic printing process, is transferred from the layer carrier to the workpiece. After printing by means of the electrophotographic printing process, the layer carrier is completely rolled onto a roll. The invention further relates to a device for the successive layer-by-layer construction of a workpiece and to a layer carrier with a roll.

[0002] US 2014 / 0182775 A1 describes a method for producing a workpiece from multiple layers. In this method, a carrier material is coated with layers made of polyester resin using a screen printing process, and the polyester resin is dried. The carrier material, wound onto a roll, is placed in a device, unwound from the roll, and the workpiece is constructed by transferring the layers from the carrier material to the workpiece.

[0003] Another manufacturing method is disclosed in US 2015 / 0024168 A1, which describes a method for printing a three-dimensional part and a support structure using an electrophotography-based additive manufacturing system. In the method, a support layer of the support structure is formed from a soluble support material using a first electrophotography device, and the support layer is transferred to a transfer medium. Furthermore, a layer of the three-dimensional part is formed from an ABS material using a second electrophotography device and is also transferred to the transfer medium. The support layer and the layer are then gradually bonded together layer by layer to form the workpiece.

[0004] Another method for producing a workpiece from several layers is known from US 2013 / 186558 A1.

[0005] Various manufacturing processes for the layer-by-layer construction of a workpiece are known and used for rapid prototyping. One of these processes is MultiJet Modeling, in which workpieces are built layer by layer using a print head with multiple nozzles. In Laminated Object Manufacturing, layers of ceramic, plastic, or metal foils, or paper, are laminated together to build workpieces. In Stereolithography, workpieces are built up gradually by curing a liquid photopolymer layer by layer using a laser.

[0006] The known processes have the disadvantage that they are time-consuming and therefore not suitable for the production of larger quantities.

[0007] The invention is based on the object of creating a method of the type mentioned at the outset with which the manufacturing process can be handled more flexibly and carried out more quickly.

[0008] According to the invention, this object is achieved in that the layer is formed from different materials and at least one of the layers is formed from several sub-layers arranged one above the other.

[0009] To form the workpiece, several layers are successively bonded together, and the layer carrier is detached from the respective layer bonded to the workpiece. Since the layers can be transferred at high frequencies and not only a single workpiece can be produced, but also a large number of workpieces can be built simultaneously, the inventive method is suitable for mass production.

[0010] The layer carrier is rolled onto the roll for easy storage and / or transport. To transfer the layers to the workpiece, the layer carrier is unrolled along with the layers and moved to the transfer device.

[0011] The printing step of the substrate, which is significantly faster than transferring the layer from the substrate to form the workpiece, and the layer transfer step can be separated. This allows for better management of the production of the layers and the workpiece.

[0012] Furthermore, it opens up the possibility of locating the electrophotographic printing device at a different location than the transfer device. If necessary, several transfer devices, possibly located at different locations, can be supplied with the layer carriers containing the layers from a single printing device.

[0013] When the layer carrier is completely rolled up onto the roll and the roll is set up for use in a device for transferring the layer from the layer carrier to the workpiece, the layer carrier and the layers arranged thereon form an intermediate product in the process according to the invention.

[0014] In one embodiment of the invention, the layer is transferred to the workpiece in a printing process using a transfer device of the device mentioned above. The layer is expediently applied to the workpiece, which is mounted on a preferably movable workpiece carrier, wherein the layer carrier is preferably moved toward the workpiece and / or the workpiece is moved toward the layer carrier. The layer can be bonded to the workpiece under slight pressure, which is preferably exerted on the layer by means of a stamp.

[0015] Alternatively or additionally, the layer and the workpiece can be electrically charged and / or magnetized such that the layer is moved toward the workpiece by an electrical or magnetic force of attraction or repulsion. While it would be conceivable to arrange the layer on an intermediate carrier before transferring it to the workpiece, for example, on a cylinder as in offset printing, and only then transfer it directly to the workpiece, in a preferred embodiment of the invention, the transfer device comprises a stamp that is designed to rest on the layer carrier and serves as a counterholder for the layer during transfer.

[0016] For transfer, the stamp is expediently moved toward the workpiece and / or the workpiece is moved toward the stamp, preferably by moving the workpiece carrier, and the stamp and workpiece are moved away from each other again after the layer has been applied, whereby the layer detaches from the carrier element. In order for the aforementioned electrical and / or magnetic attraction or repulsion force to develop, the device could be provided with a device for applying an electric field to the layer and / or the stamp on the one hand and the workpiece on the other hand, in order to support the transfer by means of electrostatic attraction or repulsion forces. The stamp could be provided so that it is electrically chargeable and / or magnetized or magnetizable.Furthermore, it would be conceivable to design the stamp itself as an electromagnet or to arrange an electromagnet on the stamp or in the vicinity of the stamp, by means of which a magnetic field is formed for transferring the layer at the times at which the layer is to be transferred to the workpiece.

[0017] The said transfer device is expediently provided for arranging the layer carrier in a transfer position in which the respective layer can be transferred to a location provided on the workpiece.

[0018] In one embodiment of the invention, the transfer device comprises a positioning unit which has a sensor by means of which the position of the layer carrier and / or the layer to be transferred can be determined, and which is designed to arrange the layer carrier or the layer in the respective transfer position based on information received from the sensor. While it would be conceivable to provide the sensor in such a way that it interacts with electrically conductive or magnetic materials applied to the layer carrier, in the preferred embodiment of the invention it is formed by a camera which records at least one area in which the layers are transferred to the workpiece. The respective position of the layer orThe position of the layer carrier is conveniently compared by means of a computer with the position on the workpiece where the layer is to be applied and the layer carrier is moved into the transfer position if necessary.

[0019] Alternatively or additionally, the layer carrier can be provided with at least one marking that can be detected by the sensor and by means of which it can be arranged in the respective transfer position.

[0020] In one embodiment of the invention, several of the layers intended for superimposition during the construction of the workpiece are arranged one after the other on the layer carrier in the direction of movement of the layer carrier relative to the workpiece. To transfer the respective layer, the layer carrier is gradually moved into the transfer position for the layer.

[0021] In a particularly preferred embodiment of the invention, several of the workpieces are constructed simultaneously, with several of the preformed layers being transferred to different workpieces at the same time. Advantageously, a plurality of workpieces can be constructed in a single operation. The workpieces to be formed can be of the same type or different. They preferably have the same shape, structure, color, and material(s), or different shapes, structures, colors, and / or materials.

[0022] Conveniently, layers intended for placement in the same position in the respective workpieces are transferred simultaneously. It is understood that the various workpieces can be arranged simultaneously on a single carrier body and / or joined together using a single stamp.

[0023] In a further embodiment of the invention, the layer is formed on the substrate prior to its transfer using a printing process. Xerographic printing processes are particularly suitable for this purpose. Each of the layers, or, if several layers are to be applied one behind the other and / or next to the other on the substrate, the plurality of layers, is / are preferably created using a digitized print image that specifies the structure of the respective layer(s) to be created.

[0024] Since the layers can also be formed at high frequencies on the layer carrier by means of the printing process and a layer formation device provided for this purpose, in particular a printing device, preferably an electrophotographic printing device, the time for the entire production of the workpiece can be significantly reduced compared to the above-mentioned processes.

[0025] The printing process advantageously comprises the steps of generating an electrical latent image or charge image on a light-sensitive recording material, which generally contains a photoconductive material; subsequently developing the latent image or charge image with a layer-forming material; transferring the resulting image to the support; and fixing the layer-forming material, e.g., using heat, pressure, or solvent vapor to form the layer. Various development processes are known for visualizing electrical latent images or charge images, for example, the magnetic brush process, the cascade development process, the fur brush process, the powder cloud process, the contact development process, the skip development process, and the magnetic dry process.

[0026] A laser printer proves to be very advantageous for the electrophotographic printing process. The layer can be printed at a resolution of up to 5000 dpi. It has proven advantageous to set the laser power, discharge corona, contrast potential, and layer-forming agent application as high as possible. The optimal process conditions can be optimized through simple experiments, depending on the specific printing equipment used.

[0027] However, it would also be conceivable to apply the layer using an inkjet printer.

[0028] The layer is expediently formed with a thickness of ≥ 0.001 mm, preferably ≥ 0.01 mm, and transferred to the workpiece. This advantageously also allows a relatively high resolution to be achieved in the direction in which the workpiece is built up. However, the layer is particularly preferably printed with a thickness between 0.01 and 0.1 mm. To build the workpiece as quickly as possible, the layer could also be applied to the layer carrier with a relatively large thickness, e.g., with a maximum thickness of 0.1 mm - 3 mm, preferably a maximum of 1 mm - 2 mm.

[0029] While it would be conceivable to spatially and temporally separate the formation of the layers on the layer carrier and the construction of the workpiece from the layers, for example, to enable transport or temporary storage of the layer carrier provided with the layers, the production of the layers and their transfer to the workpiece are carried out in a single operation in the preferred embodiment of the invention. For this purpose, the device is expediently configured to move the layer carrier to the transfer device immediately after it has been provided with the layer.

[0030] The layer carrier is preferably designed in such a way that the layers adhere to it, especially when the layer carrier is moved, but can be completely detached from it during construction of the workpiece. Using a flexible layer carrier has proven particularly advantageous for handling.

[0031] The layer carrier is preferably web-shaped and, if necessary, intended for arrangement on a roll. If several layers are arranged on the layer carrier, one embodiment of the invention provides for the layer carrier to be rolled up together with the layers arranged thereon so that it can be easily stored and / or transported.

[0032] Furthermore, the layer carrier could be provided as a plurality of individual sheets, which can preferably be stacked in the printed state. For transferring the respective layer or layers to the workpiece, the individual sheets could be transported from a stack of individual sheets to the transfer device, preferably by means of a device for dispensing individual individual sheets.

[0033] In a further embodiment of the invention, the layer carrier is designed as an endless belt, i.e., a closed ring, and the layer is gradually applied to and removed from it during the transfer process. It is understood that the endless belt is moved circumferentially past the layer-forming device so that it can be coated with the layer, and is moved behind it past the workpiece in the direction of movement of the endless belt so that the layer can be transferred to the workpiece.

[0034] The substrate is preferably a film or paper, especially silicone paper, wax paper, or paper coated with polytetrafluoroethylene (Teflon-coated). Since film and paper are flexible and, if formed in webs, can be rolled up, they are particularly well suited for the process.

[0035] In one embodiment of the invention, the layer is formed from plastic, ceramic, glass, metal oxide and / or metal and optionally a carrier material therefor and / or, optionally as a support material, wax, wherein it may comprise different materials or combinations of materials.

[0036] As already mentioned, the layer could be electrically chargeable and / or magnetized or magnetizable.

[0037] The plastic, the ceramic, the glass, the metal oxide, and / or the metal are advantageously present as particles. In one embodiment of the invention, the particles are processed into a layer-forming agent comprising the particles and the carrier material, preferably a binder resin. The layer-forming agent advantageously comprises fine particles, each comprising the carrier material and the particles dispersed in the carrier. The particles preferably have a diameter of 1 to 100 µm, with an average particle size of 5 to 30 µm being particularly preferred. The proportion of particles in the layer-forming agent is advantageously 10 to 70 wt.%.

[0038] The layer-forming agent is preferably prepared by intimately mixing the particles and the carrier material, kneading the resulting mixture in the melt, cooling it, grinding it, preferably pulverizing it, and classifying it to the desired particle size.

[0039] The carrier means is preferably designed in such a way that it burns without residue during a subsequent heat treatment, and its elasticity is adjusted so that it can absorb the desired amount of particles and preferably does not break when the mixture is ground (pulverized).

[0040] The binder resin is preferably composed of vinyl monomers. Specific examples of vinyl monomers include: styrene and its derivatives, such as styrene, ortho-methylstyrene, methylstyrene, para-methylstyrene, para-methoxystyrene, and para-ethylstyrene; methacrylic acid esters, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; Acrylic acid esters, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; derivatives of acrylic acid and methacrylic acid, such as acrylonitrile, methacrylonitrile and acrylamide. Further examples are dicarboxylic acids with a double bond and their derivatives, such asMaleic acid, monobutyl maleate, dibutyl maleate, monomethyl maleate, and dimethyl maleate; vinyl esters such as vinyl chloride, vinyl acetate, and vinyl benzoate; vinyl ketones such as vinyl methyl ketone or vinyl ethyl ketone; and vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether. These monomers can be (co)polymerized either individually or in a mixture of two or more. It is particularly preferred to use styrene or its derivatives alone or in combination with other of the above monomers or ester derivatives. Polyurethanes, polyamides, epoxy resins, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, and paraffin waxes may also be suitable. Several of the above binder resins may also be used in combination.

[0041] In one embodiment of the invention, the layer-forming agent comprises a charge control agent, preferably electrostatically charged or chargeable, in order to provide the layer with an electrostatic charge for the electrophotographic printing process, and / or an agent for improving flowability. The charge control agents can be formed by carbon black, iron black, graphite, nicrosin, metal complexes of monoazo dyes, Hansa Yellow, Benzidine Yellow, zinc atoms and / or various lake pigments. The flowability can be improved, for example, by hydrophobic, colloidal silicon dioxide. The latter agents are preferably contained in the layer-forming agent in an amount of 0.05 to 5 wt.%, and particularly preferably 0.1 to 2 wt.%. Furthermore, the layer-forming agent could contain magnetic particles, such asIron, manganese, nickel, cobalt, chromium, magnetite, hematite, various ferrites, manganese alloys, and other ferromagnetic alloys. It is also conceivable for the coating agent to contain additional carrier particles, such as iron powder or glass beads.

[0042] In one embodiment of the invention, at least one of the layers is formed from several sublayers, preferably made of different materials, which are arranged successively on the carrier element to form the layer. The sublayers are expediently formed one above the other and / or next to the other, so that two- or three-dimensional structures can also be constructed within the layer to be arranged on the carrier element.

[0043] For this purpose, the printing device mentioned expediently has at least two printing drums, by means of which one of the materials can be arranged on the layer carrier or, when building up the layer, on one of the already applied partial layers.

[0044] In one embodiment of the invention, at least one of the partial layers or one of the layers is formed by a support material intended to be completely separated, preferably melted, from the workpiece. The support material, which is preferably formed from wax, in particular natural or synthetic wax, may be necessary for forming certain workpiece geometries, for example, cavities, curvatures, or undercuts, to ensure that the workpiece is sufficiently stable, and is removed from the workpiece after construction.

[0045] In a further embodiment of the invention, the device comprises a device for generating ultrasound and / or a heating device, which preferably comprises a laser and / or an infrared lamp. The heating device can be used to assist the detachment of the layer from the substrate, and can also heat the layer and / or the workpiece to bond them together.

[0046] In one embodiment of the invention, an agent for dissolving the carrier material is applied, preferably by spraying, to the layer after it has been transferred to the workpiece. The solvent is expediently applied in such a way that it partially dissolves the carrier material of the layer and, in the area of ​​the workpiece to which the layer has been applied, the carrier material of the workpiece, so that the layers bond together, crosslinking the carrier materials of the layer and the workpiece. Advantageously, when applying the solvent, it is not necessary to heat the layer or / and apply pressure to bond it to the workpiece. Suitable solvents include, for example, water or toluene.

[0047] The layers are expediently provided with an adhesive layer by means of which they can be connected to one another, wherein the adhesive layer can be formed by the last partial layer to be applied to the layer.

[0048] In one embodiment of the invention, at least one of the partial layers or one of the layers is formed by a support material intended to be completely separated, preferably melted, from the workpiece. The support material, which is preferably formed from wax, preferably natural or synthetic wax, may be necessary for forming certain workpiece geometries, for example, cavities, curvatures, or undercuts, to ensure that the workpiece is sufficiently stable, and is removed from the workpiece after construction.

[0049] In a further embodiment of the invention, each of the layers is heated individually or several of the layers together after it has been applied to the workpiece in order to bond them to the workpiece and, if necessary, to one another. Advantageously, the layer or layers can then be cured or sintered directly layer by layer and, if necessary, the support material can be separated from the workpiece. A heating device provided for this purpose expediently comprises a laser, preferably a laser diode, and is designed to heat the respective layer or layers evenly or, if necessary, specifically to different temperatures. During heating, the carrier material and / or the support material can be removed. The heating is carried out depending on the respective material in the layer or layers.the layers, for ceramic, glass, metal oxide and / or metal, a temperature in the range of 600 to 1500 °C, for plastic in the range of 150 to 600 °C.

[0050] Depending on the material or materials from which the workpiece is constructed, it may be expedient, particularly if the layers have not previously been heated to bond them, to heat-treat, in particular to sinter, the workpiece after all the layers have been arranged in order to bond the layers to one another and in particular to bond the individual particles into a one-piece body forming the workpiece.

[0051] During such a heat treatment, the carrier material and / or support material can also be removed. Depending on the material used, the heat treatment is carried out at a temperature in the range of 600 to 1500 °C for ceramic, glass, metal oxide, and / or metal, and in the range of 150 to 600 °C for plastic.

[0052] It is understood that the formation of the layer on the substrate and the transfer of the layer to the workpiece are computer-controlled, preferably using a data set containing the shapes and dimensions of the workpiece to be built. Such a data set is typically a CAD file or similar.

[0053] In one embodiment of the invention, the device comprises, for its control and / or regulation, a control and / or regulation device by means of which the formation of the layer on the layer carrier, in particular the formation of the partial layers and the corresponding material selection, and / or the transfer of the layer to the workpiece, in particular the transfer device including the movement of the layer carrier, the stamp and / or the workpiece carrier, the heating device and / or the device for generating ultrasound, can be controlled and / or regulated.

[0054] In one embodiment of the invention, the control and / or regulating device is provided to determine from the said data set the shape of the layer or partial layers to be produced and / or to determine the material to be used, to set up the device accordingly to carry out the method and, if necessary, to carry out the method.

[0055] The invention will be explained in more detail below with reference to exemplary embodiments and the accompanying drawings, which refer to the exemplary embodiments. They show schematically Fig. 1a device according to the invention, Fig. 2in side view details of by means of the device according Fig. 1 layers that can be produced, Fig. 3 in plan view details of by means of the device according Fig. 1 producible layers, Fig. 4 shows a further device according to the invention, Fig. 5 shows a plan view of a printed layer carrier, and Fig. 6 shows a further device according to the invention.

[0056] One in Fig. 1 The device according to the invention shown comprises a xerographic printing device 12 configured to print layers 2, 3, 4 onto a layer carrier 5 formed by a paper web. It further comprises a transfer device 19, by means of which the layers 2, 3, 4 can be transferred from the layer carrier 5 to a workpiece 1, and a control and / or regulating device 24 for controlling and / or regulating the printing device 12 and the transfer device 19.

[0057] The printing device 12 comprises a holder for a roll 13 on which the layer carrier 5 is rolled up, as well as five printing drums 14, 15, 16, 17, 18 provided with a light-sensitive coating, which are designed for printing different materials.

[0058] The transfer device 19 comprises a carrier body 20, on which the workpiece 1 is arranged and built up, and a stamp 6, by means of which a first layer of the workpiece 1 is first arranged on the carrier body 20 and then further layers 2, 3, 4 are applied to the workpiece 1 that is being built up. The stamp 6 is movable in the direction of the double arrow S in order to apply the layers 2, 3, 4 to the carrier body 20 or the workpiece 1 for transfer and then to release them again, detaching the layer carrier 5 from the layers 2, 3, 4 of the workpiece 1.

[0059] The transfer device 19 further comprises a device (not shown here) for generating ultrasound, by means of which ultrasound can be directed onto the stamp in order to assist the detachment of the layer 2, 3, 4 from the layer carrier 5 during the transfer of the respective layer 2, 3, 4.

[0060] In addition, the transfer device 19 is provided with a laser (not shown here), by means of which the layer 2, 3, 4 and / or the workpiece 1 can be heated shortly before the transfer in an area to which the layer 2, 3, 4 is to be applied in order to bond the layer 2, 3, 4 to the workpiece 1.

[0061] In order to be able to arrange the layer carrier 5 with sufficient accuracy relative to the workpiece 1 in respective transfer positions in which the layers 2, 3, 4 can be transferred onto the workpiece, the transfer device 19 further comprises a camera (not shown here) which captures the area in which the workpiece 1 is covered with the layers 2, 3, 4 and which is connected to the control and / or regulating device 24 for data transmission.

[0062] Viewed in the feed direction T of the layer carrier 5, behind the transfer device 19, a further holder for a roller 21 is provided, onto which the layer carrier 5 can be rolled after the layers 2, 3, 4 have been transferred to the workpiece 1.

[0063] The mounts for the rollers 13 and 21 are each provided with a motor for moving the layer carrier 5. The motors can be controlled and / or regulated by the control and / or regulating device 24 to adjust the position of the layer carrier 5 relative to the workpiece 1 or the carrier body 20. For this purpose, the layer carrier 5 can be moved in the feed direction T and, if necessary, perpendicular thereto.

[0064] The control and / or regulation device 24 comprises a computer configured to generate information from CAD files describing the shape of the workpiece 1 to be produced, which information can be used to determine the shapes of the layers 2, 3, 4 and the materials to be used to form them. From this information, the computer generates print images, which can be used to control the xerographic printing device 12, and determines transfer positions for the arrangement of the layers 2, 3, 4 during transfer to the workpiece 1.

[0065] To construct workpiece 1, proceed as follows.

[0066] First, a CAD file is loaded into the computer 1, which contains information about the shape of the workpiece 1 and from which the print images for the printing device 12 are generated.

[0067] Based on this information, the control and / or regulating device 24 sets up the printing device 12 and causes the layer carrier 5 to be set in motion by means of the stepper motors. The layer carrier 5 is then guided from the roll 13 through the printing device 12, and in the process, partial layers 7, 8, 9, 10, 11 are formed by the printing drums 14, 15, 16, 17, 18, from which the layers 2, 3, 4 are built up (see Fig. Fig. 2 und 3 ).

[0068] For example, the printing drum 14 can be provided for printing a partial layer 7 made of a thermoplastic, the printing drum 15 for printing a partial layer 8 made of metal, the printing drum 16 for printing a partial layer 9 made of ceramic, the printing drum 17 for printing a partial layer 10 made of a thermosetting plastic and the printing drum 18 for printing an adhesive layer 11, wherein it should be noted that the partial layers 7, 8, 9, 10, 11 can contain a carrier material in order to make the various, possibly powdery, materials flowable.

[0069] A correspondingly constructed layer is shown in Fig. 2a in a side view. As in Fig. 2b in a side view and in Fig. 3 shown in a plan view, sublayers 7', 8', 9', 10' could also be divided into one plane and have different materials in the plane. Fig. 3a, 3b und 3c It is intended to show, merely by way of example, using partial layers 7', 7", 7", that different patterns can be formed in the respective partial layer planes in order to create a three-dimensional structure in the workpiece 1. Individual partial layers could also be formed from a support material that merely serves to stabilize the workpiece 1 during its construction and is later removed.

[0070] After printing, layers 2, 3, and 4 are moved with the layer carrier 5 into the transfer device 19. As soon as one of the layers 2 is to be transferred to the workpiece 1, the camera detects the position of layer 2 and transmits it to the control and / or regulating device 24, which moves the layer carrier 5 into the respective designated transfer position using the motors. As soon as layer 2 is in the transfer position, the adhesive layer (partial layer 11) is heated by the laser, and the stamp 6 is moved toward the workpiece 1 to press layer 2 against the workpiece 1 and bond it to the workpiece 1.

[0071] After the workpiece 1 has been completely built up, it is removed from the transfer device 19 and sintered to complete a product, whereby the carrier material and the support materials are removed from the workpiece 1 and the various layers 2, 3, 4 and partial layers 7, 8, 9, 10 are further bonded together.

[0072] The following refers to the Fig. 4 bis 6 Reference is made in which the same or equivalent parts are given the same reference number as in Fig. 1 and 2 and each reference number is preceded by a letter.

[0073] Another, in Fig. 4 The device according to the invention shown differs from that according to Fig. 1 in that a printing device 12a and a transmission device 19a are arranged spatially separated from one another.

[0074] A layer carrier 5a is wound onto a roll 22 after being printed with layers 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c. The roll 22, now provided with the printed layer carrier 5a, can be temporarily stored and transported and, in order to build up a workpiece 1a, 1b, 1c, is placed on a holder of the transfer device 19a, from which the layer carrier 5a can be guided to the carrier body 20a and the stamp 6a for workpiece construction, as described above.

[0075] The Fig. 4 and 5 further illustrate how several workpieces 1a, 1b, 1c can be constructed simultaneously by means of the method according to the invention.

[0076] By means of printing drums 14a, 15a, 16a, 17a, 18a, several Fig. 5 Groups of layers 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c are formed, shown in plan view, which have the same shape and structure as groups. The layers 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c are then built up, as explained above, by means of a stamp 6a on a carrier body 20a simultaneously with the workpieces 1a, 1b, 1c, which have the same shape and structure.

[0077] It goes without saying that with appropriate control and / or regulation, workpieces that differ from one another in their shape and / or structure can also be built simultaneously.

[0078] Fig. 5 also shows markings 25 which are applied to the layer carrier 5 during printing and are detected by a camera not shown here in order to bring the layer carrier 5a into a transfer position by a corresponding movement controlled by a control and / or regulating device 24b.

[0079] In a further embodiment, the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c are electrically charged when they are arranged on the layer carrier 5, 5a and the workpiece 1 or the workpieces 1a, 1b, 1c are provided with an opposite charge to the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c, so that the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c, when they are moved to the workpiece 1 or to the workpieces 1a, 1b, 1c, are attracted to the workpiece 1 or the workpieces 1a, 1b, 1c and are arranged on the workpiece 1 or the workpieces 1a, 1b, 1c due to the electrical attractive forces.

[0080] Alternatively or additionally, the stamp 6,6a could be charged in such a way that an arrangement of the layers 2,3,4 or 2a,2b,2c,3a,3b,3c,4a,4b,4c on the workpiece 1 or the workpieces 1a,1b,1c is supported by electrostatic repulsion.

[0081] Alternatively or additionally, the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c could be magnetized or magnetizable and the carrier body 20, 20a and / or the workpiece 1 or the workpieces 1a, 1b, 1c could be magnetized in such a way that it or they can magnetize the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c. Alternatively or additionally, the stamp 6 could be magnetized such that it repels the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c, or it could be provided with an electromagnet that creates a magnetic field by which the layers 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c are moved toward the carrier body 20, 20a or the workpiece 1 or the workpieces 1a, 1b, 1c. Advantageously, the electromagnet can generate the magnetic field selectively at the times at which the respective layer 2, 3, 4 or 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c is in the transfer position.

[0082] In Fig. 6 A further device according to the invention is shown, which differs from those according to the Fig. 1 and 4 differs in that a layer carrier 5d is formed by an endless belt that is moved via deflection rollers 25, 26, 27, 28 through a printing device 12d and a transfer device 19d. After transferring layers 2d, 2e, 2f to workpieces 1d, 1e, 1f, the respective location of the layer carrier 5d on which the respective layers 2d, 2e, 2f were arranged is guided back to the printing device 12d in the direction of the arrows. If necessary, the layer carrier 5d could be cleaned along the path between the transfer device 19d and the printing device 12d by means of a cleaning device (not shown here).

[0083] The device differs from the devices according to the Fig. 1 and 4Furthermore, in that the transfer device is provided with spraying devices 29, 30, by means of which the workpieces 1d, 1e, 1f are sprayed with solvent, for example water or toluene, for dissolving a carrier material, e.g., binder resin, of the layers 2d, 2e, 2f transferred onto the workpieces 1d, 1e, 1f. By spraying the workpieces 1d, 1e, 1f each covered with new layers 2d, 2e, 2f in the areas on which the new layers 2d, 2e, 2f are arranged, the carrier material of the layers 2d, 2e, 2f and the workpieces 1d, 1e, 1f is dissolved, so that they are each bonded to one another by cross-linking the respective carrier materials.

[0084] In addition, the transfer device 19d has laser diodes 32, 33, by means of which the new layers 2d, 2e, 2f deposited on the workpieces 1d, 1e, 1f can be heated in order to cure or sinter the layers 2d, 2e, 2f together with the workpieces 1d, 1e, 1f, thereby bonding them. To position the workpieces 1d, 1e, 1f in a suitable position for spraying with the solvent and heating by the laser diodes 32, 33, a carrier body 20a can be arranged on a height-adjustable base 34 for its height adjustment.

Claims

1. Production method in which a workpiece (1) is built up layer by layer in a gradual manner and, for build-up of the workpiece (1), a respective preformed layer (2, 3, 4), which is formed on a layer carrier (5) by means of an electrophotographic printing process, is transferred from the layer carrier (5) to the workpiece (1), wherein the layer carrier (5) is completely rolled onto a roller (22) after printing by means of the electrophotographic printing process, characterized in that the layer (2, 3, 4) is formed from different materials, and at least one of the layers (2, 3, 4) is formed from multiple sub-layers (7, 8, 9, 10, 11) which are arranged one above the other.

2. Method according to Claim 1, characterized in that the layer (2, 3, 4) is transferred to the workpiece (1) in a printing operation, wherein preferably the layer (2, 3, 4), preferably by means of a ram (6), is applied to the workpiece (1) or the workpiece (1) is applied to the layer (2, 3, 4).

3. Method according to Claim 1 or 2, characterized in that multiple ones of the workpieces (1a, 1b, 1c) are built up simultaneously, wherein multiple ones of the preformed layers (2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c) are transferred to various ones of the workpieces (1a, 1b, 1c) at the same time.

4. Method according to one of Claims 1 to 3, characterized in that the layer (2, 3, 4) is formed on the layer carrier (5) by xerography, preferably by means of a laser printer.

5. Method according to one of Claims 1 to 4, characterized in that multiple ones of the layers (2, 3, 4) are arranged one next to the other and / or one behind the other on the layer carrier (5), and, for transfer of the respective layer (2, 3, 4), the layer carrier (5) is, in a gradual manner, arranged in a transfer position in which the respective layer (2, 3, 4) can be transferred to the workpiece (1).

6. Method according to one of Claims 1 to 5, characterized in that the layer carrier (5) is formed by a film or a paper, in particular silicone paper, wax paper or polytetrafluoroethylene-coated paper.

7. Method according to one of Claims 1 to 6, characterized in that, for arrangement of the layer carrier (5) in the respective transfer position, a position of the layer carrier (5) and / or of the layer (2, 3, 4) is ascertained by means of a sensor, preferably a camera, and the layer carrier (5) is preferably provided with at least one marking, on the basis of which the position thereof can be determined.

8. Method according to one of Claims 1 to 7, characterized in that the layer (2, 3, 4) is released from the carrier element (5) while being heated, preferably by means of infrared radiation or by means of a laser, and / or under the action of an electrical and / or magnetic force of attraction or force of repulsion and / or of ultrasound.

9. Method according to one of Claims 1 to 8, characterized in that the layer (2, 3, 4) is formed from ceramic, glass, plastic, wax, metal oxide and / or metal and possibly a carrier material therefor.

10. Method according to one of Claims 1 to 9, characterized in that the sub-layers (7, 8, 9, 10, 11) are arranged one after the other on the carrier element (5).

11. Method according to one of Claims 1 to 10, characterized in that a means for dissolving a carrier material of the layer (2, 3, 4) is applied to, preferably sprayed onto, the layer (2, 3, 4) after the latter has been transferred to the workpiece (1), wherein the solvent is preferably applied in such a way that it dissolves the carrier material of the layer (2, 3, 4), and, in a region of the workpiece (1) on which the layer (2, 3, 4) bears, the carrier material of the workpiece (1), so that the layer (2, 3, 4) is bonded by cross-linking of the carrier materials of the layer (2, 3, 4) and the workpiece (1) with one another.

12. Method according to one of Claims 1 to 11, characterized in that the workpiece (1) is heat-treated, preferably sintered, wherein preferably the workpiece (1), in its entirety, or each individual one of the layers (2, 3, 4), or multiple ones of the layers (2, 3, 4), together, after the arrangement thereof on the workpiece (1), is / are heated, preferably by means of a laser beam.

13. Apparatus for building up a workpiece (1) layer by layer in a successive manner, having an electrophotographic printing device (12) for forming (12) a layer (2, 3, 4) on a layer carrier (5), and having a device (19) for transferring the layer (2, 3, 4) from the layer carrier (5) to the workpiece (1), wherein the electrophotographic printing device (12) is intended for completely rolling the layer carrier (5) printed with the layer (2, 3, 4) onto a roller (22), which is configured for use in the transfer device (19), characterized in that the printing device (12) is intended for forming the layer (2, 3, 4) from different materials and for forming at least one of the layers (2, 3, 4) from multiple sub-layers (7, 8, 9, 10, 11) which are arranged one above the other.

14. Apparatus according to Claim 13, characterized in that the transfer device (19) is configured to bond the layer (2, 3, 4) to the workpiece (1) and to release said layer from the layer carrier (5), wherein preferably the layer carrier (5) is movable towards the workpiece (1) and / or the workpiece (1) is movable towards the layer carrier (5).

15. Layer carrier (5) with roller (22), wherein layers (2, 3, 4) are arranged on the layer carrier (5), which is completely rolled onto the roller (22), and are intended for build-up of a workpiece (1) layer by layer, and the roller (22) is configured for use in a device (19) for transferring the layers (2, 3, 4) from the layer carrier (5) to a workpiece (1), wherein the layers (2, 3, 4) are applied to the layer carrier (5) by means of an electrophotographic printing process, characterized in that at least one of the layers (2, 3, 4) is formed from different materials, and at least one of the layers (2, 3, 4) is formed from multiple sub-layers (7, 8, 9, 10, 11) which are arranged one above the other.