LAYER-BY-LAYER PRODUCTION OF MOLDED ARTICLES

Abstract

The invention relates to a method for manufacturing molded articles consisting of at least one molded article layer, said method comprising the steps of a) putting a layer support in place for accommodating at least one molded article layer; b) applying a molded article layer to a printing plate using a shaping tool; c) positioning the printing plate and the layer support or a previously produced molded article layer relative to one another; d) curing the molded article layer such that said layer becomes a previously molded article layer, and transferring the molded article layer; e) if necessary, putting the printing plate in place for accommodating additional molded article layers and repeating steps b) to d). The invention further relates to an apparatus for carrying out the disclosed method as well as to the use of molded articles obtained thereby.

Claims

1-22. (canceled)

23. A method for manufacturing molded articles consisting of at least one molded article layer, comprising the steps a) A layer carrier is made available for accommodating at least one molded article layer; b) A molded article layer is applied onto a printing plate, wherein the molded article layer is applied by a shaping tool onto the printing plate; c) Positioning of printing plate and/or layer carrier with respect to an older molded article layer and relative to one another, in particular contacting the molded article layer to the layer carrier or to an older molded article layer; d) Curing of the molded article layer so that it becomes an older molded article layer itself or forms a composite with such a one and transfer of the molded article layer(s) from the printing plate onto the layer carrier; e) Possible making the printing plate available for accommodating other molded article layers and repetition of the steps b) to d).

24. The method according to claim 23, wherein the shaping tool is a template and in particular the molded article layer is defined by recesses of the shaping tool.

25. The method according to claim 23, wherein the printing plate is designed in such a manner that the molded article layer poorly adheres to it and has a surface energy less than 40 mN/m.

26. The method according to claim 23, wherein the older molded article layer on the layer carrier or the layer carrier itself is provided with an adhesion promotor before a next molded article layer is applied on it.

27. The method according to claim 24, wherein a plastically deformable mass is applied through the recesses of the shaping tool onto the pressure plate in order to form the molded article layer.

28. The method according to claim 23, wherein the method according to step d) also comprises the following step: f) separation of the printing plate from the cured molded article layer.

29. The method according to claim 28, wherein at least one of the plurality of plastically deformable masses serves as support mass of the molded article and can be removed again from the molded article by mechanical, chemical or thermal methods.

30. The method according to claim 23, wherein the molded article is sintered, in particular is sintered after the conclusion of the building up of the molded article.

31. The method according to claim 23, wherein the curing comprises a polymerization step, in particular a polymerization step selected from the group consisting of photo-induced, thermally induced or chemically induced polymerization.

32. The method according to claim 31, wherein a photo-induced polymerization by loading the molded article layer with light takes place through the printing plate.

33. The method according to claim 23, wherein the curing of the molded article layer takes place by a physical process such as, for example, by drying and/or cooling off.

34. The method according to claim 23, wherein the printing plate is designed as a sheet and the transfer of the molded article layer(s) from the printing plate onto the layer carrier comprises drawing off the sheet.

35. An apparatus for producing a molded article from at least one molded article layer, in particular an apparatus for carrying out a method according to claim 23 comprising: a) A layer carrier for accommodating at least one molded article layer; b) A printing plate, and c) A shaping tool by which a molded article layer with a defined shape can be applied onto the printing plate, and wherein the printing plate and/or the layer carrier are designed in such a manner that a molded article layer applied on the printing plate can be positioned relative to the layer carrier and can be transferred onto the layer carrier or onto an older molded article layer already present on the layer carrier, and in particular the printing plate and/or the layer carrier are designed in such a manner that the molded article layer can be cured in contact with the layer carrier with an older molded article layer and can be transferred by separating the printing plate onto the layer body.

36. The apparatus according to claim 35, wherein the printing plate is designed to be permeable for light waves.

37. The apparatus according to claim 35, wherein the printing plate is provided with at least one adhesion-reducing surface or consists substantially of an adhesive-reducing material.

38. The apparatus according to claim 35, wherein the layer carrier is designed in such a manner that it has a high rigidity even under thermal stress at temperatures above 500° C.

39. The apparatus according to claim 35, comprising a plurality of shaping tools, wherein each individual shaping tool is designed in such a manner that it defines a different shape.

40. The apparatus according to claim 35, wherein the shaping tool is designed in such a manner that it defines a plurality of shapes.

41. The apparatus according to claim 35, comprising a means for applying an adhesion promotor onto a molded article layer on the layer carrier.

42. The apparatus according to claim 35, wherein the printing plate is designed as a sheet so that it can bend at least in a drawing-off direction.

43. A method, comprising: using of a molded article obtainable from the method according to claim 23 as a static mixer.

44. A method, comprising: using of a molded article obtainable from the method according to claim 23 for producing a light construction structure.

45. The method according to claim 27, wherein a paste with thixotropic properties is used as deformable mass.

46. The apparatus according to claim 37, wherein the pressure plate is provided with an adhesive-reducing surface selected from the group consisting of: stoving siliconized surface, polysilane coating, fluoropolymer coating, grease-containing coating, wax-containing coating or a coating consisting of a layer of silicate.

47. The apparatus according to claim 41, which comprises a spray apparatus for applying an adhesion promotor onto a molded article layer on the layer carrier or comprising a roller/or a stamp pad for applying an adhesion promotor onto a molded article layer on the layer carrier.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0073] The drawings used to explain the exemplary embodiments schematically show:

[0074] FIG. 1 shows a schematically simplified flow chart of a method according to the invention;

[0075] FIG. 2 shows an empty printing plate;

[0076] FIG. 3 shows the generation of molded article layers by a shaping tool;

[0077] FIG. 4 shows the generated molded article layers on the printing plate;

[0078] FIG. 5 shows the positioning of the printing plate over the layer carrier;

[0079] FIG. 6 shows the layer carrier with the molded article layers;

[0080] FIG. 7 shows a following printing;

[0081] FIG. 8 shows the transfer of the following molded article layers onto the older molded article layers;

[0082] FIG. 9 shows the layer carrier with two planes on molded article layers;

[0083] FIG. 10 shows an example with differently formed molded article layers;

[0084] FIG. 11 shows an example of a complexly built-up molded article consisting of several planes and molded article layers;

[0085] FIG. 12 schematically shows an apparatus for carrying out the method of the invention.

[0086] The same parts are basically provided with the same reference numerals in the figures.

WAYS OF CARRYING OUT THE INVENTION

Example 1

[0087] An example of a moldable mass in which photopolymers are used as binders is described here. The mass is intended for the production of ceramic structures based on aluminum oxide. The mass consists of approximately 80% aluminum oxide powder, with a quality for high-grade technical ceramic material and with an average grain size of a few micrometers. Hexane-1.6 diol diacrylate is used as binder. In order to control the rheological properties, small amounts of suitable auxiliary dispersion means are added. 0.5% 2, 2-dimethoxy-2-phenylacetophenone is added as photoinitiator.

[0088] FIG. 1 shows an exemplary flowchart for carrying out the method according to the invention. At first, a layer carrier is made available A for accommodating the molded article layer and the resulting molded article.

[0089] The layer carrier can be constructed in the present example from a level sapphire glass plate with a layer thickness of 2 mm. In a first step a thin film of an adhesive promoter can be applied on to the surface of the layer carrier so that subsequently the moistening becomes better and as a result also the connection between the layer carrier and the new form layer. To this end a stamp pad, a roller or a spray nozzle can be used C. However, this step is not obligatory and can be omitted in a few instances B.

[0090] Furthermore, a printing plate is made available. In order that step 1 can be better carried out subsequently, the surface of the printing plate is modified in such a manner that the adhesion of the cured molded article layer to it is only very slight. To this end, various techniques can be used. Suitable measures for reducing the adhesion of the molded article layer are, for example, a stoving siliconization, a thin coating with synthetic waxes, a coating with polydimethylsiloxane or with other polysilanes, a thin, grease-containing layer or a thin silicate layer. A few of the described methods for the reduction of the adhesion of the molded article layer on the printing plate require a regular repetition of the treatment of the printing plate prior to individual passages or prior to every passage. If this is the case, the printing plate is suitably prepared for the printing D, E.

[0091] Now, the plastically deformable mass is applied onto this printing plate by a template comprising recesses in the form of the molded article layer resulting in this printing procedure. To this end the template is substantially filled with the plastically deformable mass and applied on with a doctor blade in such a manner that a penetrating pressure takes place through the template onto the printing plate. Then, the template is removed.

[0092] The printing plate and the layer carrier are subsequently exactly positioned relative to one another so that their interval corresponds to the desired layer thickness and that the molded article layer is aligned exactly as desired on the layer carrier G. This takes place in such a manner that that the molded article layer physically contacts the layer carrier. A possibility for carrying this out is to rotate the printing plate substantially through 180° and to align it over the firmly mounted layer carrier. Another possibility is to work with a firmly mounted printing plate and to position the layer carrier over it.

[0093] The mass forming the molded article layer is now cured H. In the case of masses based on photopolymers, this takes place, for example, by the rays of a lamp whose light contains the wavelengths which excite the photoinitiator through the transparent printing plate. The wavelength range relevant for this expectation is frequently in the ultraviolet range of the light spectrum in the case of very shortwave frequencies. In the case of the photoinitiator of the above-cited example, 2, 2-dimethoxy-2-phenylacetophenone the relevant wavelength is, for example, 280 nm. In this case a quartz glass plate or a sapphire plate can be considered as a transparent printing plate which comprises the necessary stability and robustness as well as a sufficient transparency to light in the ultraviolet wavelength range. In the case of other deformable masses the curing step can take place by thermally induced polymerization or by thermally accelerated physical drying of the mass.

[0094] After the curing the molded article layer adheres molded article layer to the layer carrier. Thereafter, the cured layer is separated from the printing plate and as a result the is transferred from the printing plate onto the layer carrier I.

[0095] In order to facilitate the separation of the molded article layer from the printing plate the surface of the printing plate was modified in such a manner that the molded article layer it hears only slightly to it (see step C). Therefore, the adhesion of the molded article layer to the layer carrier is distinctly stronger than to the printing plate and upon the separation the molded article layer remains on the layer carrier, respectively on the older molded article layers.

[0096] If the printing is continues, that is, if other molded article layers are provided J, then the process begins again at step B. If this is the second or a later printing, the printing plate and the layer carrier are positioned relative to one another in such a manner that the current molded article layer contacts the older molded article layer. Of course, it is also possible to transfer molded article layers adjacently, that is, so that the current molded article layer also contacts the layer carrier. This is especially appropriate if molded article layers consisting of different materials but with different templates are to be printed.

[0097] Now, a thin layer of adhesion promotor is selectively applied also with the second or following molded article layer onto the older molded article layer so that a more complete moistening of the older molded article layer results by the new one C.

[0098] Now, the printing plate is selectively pretreated even with the second or following molded article layer in such a manner that the molded article layer can be subsequently readily separated from it E.

[0099] Once all desired molded article layers have been produced, cured and transferred onto the molded article carrier, the process is ended K. Depending on the deformable mass used and on the material from which the finished part is to consist, the molded article produced in this manner on the layer carrier and consisting of at least one molded article layer must finally still be supplied to a thermal treatment, for example, to a sintering or a pyrolysis.

[0100] The number of passages H is determined by the desired number of molded article layers. The entire process can take place in a computer-controlled manner. That is, an apparatus can be provided with a rack with a certain defined number of templates in order to carry out a defined sequence of printing procedures. This apparatus can be designed to be modular, as a result of which the appropriate tools can be flexibly replaced.

[0101] The execution of the method is illustrated again in an exemplary manner in the FIGS. 2 to 11 using the individual method steps.

[0102] FIG. 2 shows a printing plate 1 suitable for being used in the method of the invention. The printing plate 1 consists of a quartz glass and comprises a frame 2.

[0103] A plastically deformable mass (not shown) is supplied by a template 3 through the recesses 5 with the aid of a doctor blade 4 onto the printing plate 1 shown in FIG. 2. A printing image is produced which forms a molded article layer of the molded article to be produced. FIG. 4 shows the correspondingly printed printing plate 1. Four identical molded article layers 6 are shown on it whose shape was defined by the recesses 5 of the template 3. FIG. 5 shows how the printing plate 1 is now positioned with the molded article layers 6 over the layer carrier 7 in such a manner that the molded article layers 6 make contact with the layer carrier 7. In this position the molded article layers are cured between the printing plate and the layer carrier.

[0104] FIG. 6 shows the corresponding layer carrier 7 with the molded article layers 6 now located on it after the printing plate was separated from the cured molded article. In the meantime the printing plate 1 was made available again.

[0105] FIG. 7 shows another template 3′ with a deviating recess pattern and recesses 5′ with which the plastically deformable mass (not shown) was pressed onto the printing plate 1 in an analogous manner by a doctor blade 4. This newly printed printing plate is now also positioned over the layer carrier 7, which is shown in FIG. 8. The molded article layer 6′ make contact here with the older molded article layer 6. The frequency lines 6′ are cured in this state. A polymerization step can be readily carried out in the process steps of the curing of the FIGS. 5 and 8 in that light with the appropriate, required UV wavelength is loaded through the transparent printing plate 1 onto the molded article layers 6, 6′ to be cured.

[0106] The molded article layers 6′ form connections with the older molded article layers 6 so that the resulting molded article is substantially in one piece. The connections can be of one material to the same material. Reticulations in the case of certain materials can also occur.

[0107] FIG. 9 shows the layer carrier 7 with four molded articles which comprises two planes and consist of two molded article layers 6, 6′ integrally connected to one another.

[0108] The previous steps can be repeated as often as desired. Also, it is not necessarily obligatory that the current molded article layers are positioned in such a manner that they build up on the older molded article layers.

[0109] The example of FIG. 10 shows four molded articles in which the molded articles consist of on the whole three molded article layers 6, 6′, 6″ each of which was produced in one printing procedure. However, on the whole the molded articles consist only of two layer planes. FIG. 11 shows by way of example a molded article with five layer planes and which consists of five molded article layers 6′″, 6″″, 6′″″, 6″″″, 6′″″″.

[0110] The simple geometric structures in the figures are basically selected only for purposes of viewing. Basically, the molded article layers and their designs are not subject to any limits.

[0111] The method according to the invention is also suited for producing three-dimensional molded articles such as are shown in WO 2014/043823 A1. These molded articles comprise several molded article layers supported over each other web-by-web.

[0112] The molded article layers of the present invention can have layer thicknesses of 10 μm to 50 mm. They have especially preferably layer thicknesses of between 50 and 3000 μm. On the whole, a molded article according to the invention can have outside dimensions of between 1 mm and 5,000 mm, in particular between 4 and 500 mm, especially between 10 and 300 mm, and in particular around 50 mm, depending on the use. These magnitudes are especially suitable for the production of micromixers and catalysts. For larger structural components in light construction the appropriate dimensions can be larger.

[0113] FIG. 12 schematically shows by way of example an apparatus 11 suitable for carrying out the method of the invention. The apparatus 11 substantially comprises a frame which comprises the appropriate guides for operating the movable parts of the apparatus. A rail system serves to position a layer carrier 16. This rail system comprises an X axis of the positioning system 12, a Y axis of the positioning system 14 and a Z axis of the positioning system 13. In addition, the layer carrier 16 is connected by a rotational connection 15 supported in an articulated manner to the Z axis of the positioning system 13. This makes it possible for the layer carrier to assume the necessary positioning in all axes in a movable manner in order to carry out the method of the invention. An appropriate shaping tool can be supported in a template magazine 21. As a result of this template magazine 21, it is possible to prepare a number of predefined shaping tools such as, for example, templates or sieves and to automate the printing in this manner. During operation a replacement apparatus assumes the moving outward of the templates 22 (by way of example) over the printing plate (not shown). A doctor blade 18 is positioned above the template 22 for spreading the corresponding mass which is applied from an automatic dispensing system (not shown).

[0114] At the same time the layer carrier 15 can be impregnated with an appropriate adhesion promoter by a stamp pad 17. The positioning system of the layer carrier 16 can be determined by a vision system consisting of camera, lens and analysis software. For the sake of simplicity, the system is not shown in the present representation. Once the printing procedure has been concluded, the template used is pushed back via the guides 19 of the automatic replacement system into the magazine 21. The layer carrier 16 can now be lowered onto the printing plate by the positioning system and exactly aligned. A UV radiator 20 can now initiate the polymerization and curing through the transparent printing plate. As soon as the curing has been concluded, the layer carrier 16 can be lifted off again. As a result of this movement, in the present example the molded article layer is separated from the printing plate and forms an older molded article layer on the layer carrier 16.

[0115] This apparatus shown here is shown solely by way of example and can be constructed with several printing plates with associated template replacement apparatuses for the simultaneous printing of several structural components.