Abstract
A method for generating 3D objects includes providing a web of material, printing an image by inkjet printing in which the image corresponds to a section in a plane of the 3D object to be generated, applying a powder to the portion of the web of material that is provided with the image, cross-cutting the printed web of material into sheets, stacking the sheets on a stack of sheets, repeating the printing, powder application, cross-cutting and stacking steps, pressing the stack of sheets and exposing the object. 3D objects can be manufactured quickly, inexpensively and precisely with the method.
Claims
1. A method for generating 3D objects, the method comprising the following steps: a) providing a web of material; b) printing an image by inkjet printing, the image corresponding to a section in a plane of the 3D object to be generated; c) applying a powder to a portion of the web of material provided with the image; d) cross-cutting the printed web of material into sheets; e) stacking the sheets in precise register on a stack of sheets; f) repeating steps b) to e); g) pressing the stack of sheets; and h) exposing the object.
2. The method for generating 3D objects according to claim 1, which further comprises strengthening the web of material in a region of side edges of the web of material, before step b).
3. The method for generating 3D objects according to claim 1, which further comprises printing sections of a number of objects in nested positioning in step b).
4. The method for generating 3D objects according to claim 1, which further comprises using an inkjet printing unit with at least one inkjet printhead in step b).
5. The method for generating 3D objects according to claim 1, which further comprises using a powder unit in step c).
6. The method for generating 3D objects according to claim 5, which further comprises providing the powder unit with an electrostatic powder roller.
7. The method for generating 3D objects according to claim 4, which further comprises: placing the inkjet printing unit and the powder unit on the same side of the web of material; and guiding the web of material horizontally in a vicinity of the inkjet printing unit and the powder unit.
8. The method for generating 3D objects according to claim 5, which further comprises: placing the inkjet printing unit and the powder unit on the same side of the web of material; and guiding the web of material horizontally in a vicinity of the inkjet printing unit and the powder unit.
9. The method for generating 3D objects according to claim 1, which further comprises printing an image by inkjet printing from both sides of the web of material and simultaneously guiding the web of material vertically, in step b).
10. The method for generating 3D objects according to claim 1, which further comprises at least one of: c2) removing excess powder, or c3) prefixing the powder.
11. The method for generating 3D objects according to claim 1, which further comprises feeding-in sheets with various functionality in step e).
12. A method for generating 3D objects, the method comprising the following steps: a) providing a web of material; b) printing an image on one or both sides of the web of material by electrophotographic printing, the image corresponds to a section in a plane of the 3D object to be generated, and using two-component materials for the printing when printing on both sides; c) cross-cutting the printed web of material into sheets; d) stacking the sheets in precise register on a stack of sheets; e) repeating steps b) to d); f) pressing the stack of sheets; and g) exposing the object.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0027] FIG. 1 is a diagrammatic, side-elevational view of a system for creating 3D objects;
[0028] FIG. 2 is a side-elevational view of an alternative variant of an embodiment of a system for creating 3D objects;
[0029] FIG. 3 is a side-elevational view of the system of FIG. 1 with an additional functionality for feeding in sheets; and
[0030] FIG. 4 is a fragmentary, cross-sectional view of a printed and powdered image of various 3D objects nested in one another.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Referring now in detail to the figures of the drawings, which are not true-to-scale and in which corresponding elements and components are provided with the same reference numerals, and first, particularly, to FIG. 1 thereof, there is seen a system for creating 3D objects 1006. A web of material 1000 is provided by an unwinder 1 and is transported in a transporting direction T by web transporting elements 2, to be specific deflecting, guiding and driving transporting rollers and compensating rollers 4. The web of material 1000 is guided along under an inkjet imaging system 10. The inkjet imaging system 10 includes an inkjet printing unit 11, a powder unit 12, a suction/blowing device 13 and a device 14 for thermal prefixing. The web of material 1000 is transported through under the inkjet printing unit 11 and the powder unit 12, with inkjet fluid 1001 being printed onto the web of material 1000 by the inkjet printing unit 11 having a printhead 11.1. In the following powder unit 12, powder material 1002 is applied to the web of material 1000, with the powder material 1002 adhering to the web of material 1000 in the region of the inkjet fluid 1001. In order to avoid the powder producing dust when it is transferred onto the web of material 1000, the powder unit may be equipped with electrostatic assistance, for example an electrostatic powder roller 12.1. Optionally, the suction/blowing device 13 and/or the device 14 for the thermal prefixing of the powder material 1002 may be disposed downstream of the powder unit 12. The suction/blowing device 13 allows excess powder material 1002 to be removed. The thermal prefixing achieves the effect that the powder material 1002 adheres better to the web of material 1000 and the web of material 1000 becomes flexurally more rigid. This produces improved transporting properties of the web of material 1000. The web of material 1000, which is thus provided with powder images 100 (see FIG. 4) is subsequently divided into individual sheets 1004 by using a cross-cutter 6. The cross-cutter 6 may be constructed, for example, as a rotary cutting system with cutter rollers. In order to ensure that the cross-cut is introduced into the web of material 1000 at the correct position, a register detection system 5, which has a camera, is provided. The individual sheets 1004 are transported further by a sheet transporting device 3, for example constructed as a transporting belt, to a stacking system 7 and are stacked there on a stack of sheets 1005. The stacking system 7 has non-illustrated stops, which make it possible for the sheets 1004 to be stacked in precise register. A temperature-assisted pressing device 8, which serves for the pressing and baking of the stack of sheets 1005, may be integrated in the stacking system 7. Alternatively, the stack of sheets 1005 may be transported further to such a pressing device 8 applying a pressing force F. In the method step of pressing and baking, the powder material is cured and the 3D object 1006 to be generated is produced. In order to expose the 3D object 1006 and free it of the sheet material lying around it and surrounding the object, the pressed and baked stack of sheets 1005 is passed on to a sandblasting device 9. Alternatively, a chemical washing-out or other selective material-removing treatment method may also be used.
[0032] An alternative variant of an embodiment of a system for creating 3D objects 1006 is represented in FIG. 2. Instead of the inkjet imaging system 10 according to FIG. 1, in this case a toner imaging system 20 is used. The toner imaging system 20 has at least one toner printing unit, which is disposed on one side of the web of printing material 1000. Alternatively, however, two printing units may also be provided, with a toner printing unit being disposed on each of the two sides of the web of material 1000. A respective toner printing unit includes a photoconductor drum 21, which is assigned a digital imaging unit 22. Partially powdered toner 1003, for example resin powder, is transferred onto the photoconductor drum 21 by a developer station 23. Due to the use of the digital imaging unit 22 and an electrical application or charging unit 25, the transfer takes place in this case in a manner analogous to the transfer of toner in the case of dry toner printing. Excess powder is removed by a cleaning system 26, with the powder itself being transferred onto the web of material 1000 by an intermediate carrier 24 with a printing blanket. A thermal prefixing of the powder material on the web of material 1000 is performed by using a downstream pair of fusing rollers 27.
[0033] In the variant embodiment represented in FIG. 2, having two printing units that may also be referred to as a simultaneous printing unit, the web of material 1000 is printed on both sides. It appears to be particularly advantageous if a two-component material 1003 including components 1003A and 1003B, for example a two-component resin, is used for the printing by the printing units.
[0034] A variant of the system of FIG. 1 is represented in FIG. 3. A further inkjet print head 15 for printing colored or functional structures may be provided upstream of the stacking system 7 and sheets 1007 with additional functionality may be fed into the material stream of the sheets 1004 by a feeding-in operation e that is not represented any more specifically. It is thereby possible to produce a stack of sheets 1005, which includes both powdered and prefixed sheets 1004 and sheets 1007 with additional functionality. The sheets 1007 with additional functionality may be sheets that have a mechanical, electrical, thermal, magnetic or graphic function. In this case, a number of feeding-in devices may be provided, so that sheets 1007 with various functionality from various stacks of sheets can be pushed between the powdered sheets 1004 in each case by the feeding-in operation e.
[0035] FIG. 4 shows how an image 100 has been printed onto the web of material 1000 and powdered. A respective printed image 100 in this case represents a cross section in a specific sectional plane through the 3D object 1006 to be generated. It is particularly advantageous if, as represented in FIG. 4, a number of objects 1006 are generated simultaneously, in order to better utilize the surface area of the web of material 1000. In the example represented in FIG. 4, six objects are generated simultaneously. The rectangular cross section 101 of a first object, four circular cross sections 102 of a second object as well as an oval cross section 103 of a third object can be seen, with this third object having a further round body inside it. If only one object is to be generated, the cross section 103 may be supplemented by further cross sections 101, 102 of supporting objects, which form supporting structures.
