Ceramic printing process for the production of urns from ceramic materials using 3D printing

Abstract

The present invention relates to a ceramic printing method for producing urns from ceramic materials using 3D printing, in which a CAD model of the urn to be produced is created and, based on the CAD model, a control file, in particular a G-code file, for a 3D printer is produced, which controls the travel paths of a print head of the 3D printer, the speed of the print head and the material feed via an extruder of the 3D printer, by segmenting the produced CAD model into sections, representing the sections as points and assigning data relating to the travel paths of the print head during printing to the individual points, wherein the control file is created in such a way that at least the outermost shell layer of the urn to be produced is printed in vase mode, in which the print head of a 3D printer is moved incrementally in the Z-axis direction.

Description

[0001] The present invention relates to a ceramic printing method for producing urns from ceramic materials using 3D printing, in which a CAD model of the urn to be produced is created and, based on the CAD model, a control file, in particular a G-code file, is produced for a 3D printer, which controls the travel paths of a print head of the 3D printer, the speed of the print head and the material feed via an extruder of the 3D printer, by segmenting the produced CAD model into sections, representing the sections as points and assigning data relating to the travel paths of the print head during printing to the individual points.

[0002] In the funeral industry, pet and human urns, which can be made of ceramic materials such as porcelain, stoneware, or earthenware, are increasingly being produced using 3D ceramic printing. In this process, the ceramic material is brought to a liquid, malleable consistency that can be extruded through a nozzle in the printer's print head. The material is fed into the printer and heated by an extruder, usually a screw extruder, and conveyed to the print head. The print head moves in layers, printing the ceramic material layer by layer. The nozzle of the print head precisely defines the shape, which was predetermined beforehand. Once the printing process is complete, the finished object is dried. It is then fired in a kiln at high temperatures. This step makes the material durable. After the first firing, the ceramic object can be glazed to give it a glossy or colored surface.It is then fired again to fix the glaze. This creates a unique ceramic piece / urn that precisely matches the specifications of a computer model.

[0003] The program for a 3D ceramic printer, also called "slicing software," is created in several steps to convert a digital model into a format that the 3D printer can understand. First, a 3D model of the urn to be produced is created. This can be done with specialized 3D modeling programs such as Tinka Cut, Blender, or Fusion 360. Alternatively, ready-made models can be downloaded from the internet.

[0004] The created 3D model is then loaded into special software called a "slicer" (e.g., Cura or Trusa Slicer). This software converts the model into a format that the 3D printer understands—usually a G-code file. G-code is a series of commands that tell the 3D printer how and at what speed the print head should move and how much material should be fed to the print head via the extruder and extruded through its nozzle.

[0005] Various parameters can be adjusted in the slicing software. In particular, the layer thickness, printing speed, nozzle and print bed temperature, etc., can be varied.

[0006] Specifically, the slicing software slices the 3D model into many thin layers. These layers are then converted into G-code. Once the model is sliced, the G-code file is transferred to the printer.

[0007] The printer reads the code and begins printing the object layer by layer.

[0008] In summary, a 3D model of an urn is created, converted into printing instructions in the slicing software, and these printing instructions are executed by the 3D printer.

[0009] Conventional 3D printing methods for producing urns from ceramic materials, as previously described, have the disadvantage of creating a visible seam on the outer wall of the printed object. This is due to the fact that, after applying a ceramic layer, the print head abruptly changes its position along the Z-axis in the Cartesian coordinate system to continue printing on the next layer. This seam is visually distracting and detracts from the uniform appearance of a 3D-printed pet or human urn made from ceramic materials.

[0010] The object of the present invention is to provide a method for manufacturing urns from ceramic materials using 3D printing, in which the formation of a seam on the outside of the urn is avoided.

[0011] This task is solved in a ceramic printing process of the type mentioned above by creating the control file in such a way that at least the outermost shell layer of the urn to be produced is printed in vase mode, in which the print head of a 3D printer is moved incrementally in the Z-axis direction.

[0012] The invention is based on the idea of ​​guiding the print head of the 3D printer in such a way that it moves incrementally along the Z-axis. This allows the print head to move steadily, but almost imperceptibly, to the starting point of the next higher layer, where it can seamlessly begin and continue printing. The result is a ceramic body produced in a continuous strand, appearing perfectly uniform to the observer.

[0013] According to one embodiment of the invention, the CAD model is decomposed into individual horizontal layers, and the layers are divided into discrete sections and represented as points. Advantageously, a direction vector is determined for each point and assigned to it, which defines the movements of the print head in the horizontal XY plane and in the vertical Z direction.

[0014] In one embodiment of the invention, the direction vector for each point in the horizontal XY plane is determined by the position of the current point (A) on the respective layer (n) and a point (B) directly above it on the layer above (n+1). In the vertical Z-axis direction, the direction vector is determined taking into account the layer height and the number of points per layer. The direction vectors in the vertical Z-axis direction can be determined as follows: Ai(z)Bi(z)→=(00SchickheightResolution*i) where the resolution is the number of points per layer, i is the point iterator on the respective layer, A is the point on layer (n), B is the point on layer (n+1), and z is the Z-position.

[0015] The direction vectors in the horizontal XY plane can be determined by subtracting the XY coordinates of a point A on a layer (n) from the XY coordinates of the corresponding point B from the layer (n+1), where i is the point iterator on the respective layer.

[0016] In this way, the print head of the 3D printer can be steered so that it is moved incrementally upwards in the Z-axis direction, but at the same time, direction vectors are used to predict how the layer above of the body to be produced is oriented in order to align the current layer in the XY direction accordingly.

[0017] To further improve the print quality in the print body with regularly repeating curvatures (but without patterning) and to ensure the most accurate possible reproduction of the desired design, a further embodiment of the invention is characterized in that the superimposed points of all layers are vertically connected by polylines, wherein the number of polylines corresponds to the resolution and thus the number of points per layer, and that the polylines are divided into sections in the Z-direction and the sections are represented as points to which data relating to the travel paths of the print head for printing are assigned.Preferably, the number of sections per layer corresponds to the resolution and the data relating to the travel path are determined in such a way that the polylines are traversed one after the other, with the print head always approaching the next highest point on the following polyline in the Z-axis direction, starting from a point of a polyline with the lowest Z-height.

[0018] In this embodiment, the CAD model is decomposed into individual horizontal layers as described, and the layers are segmented into discrete sections, which are represented as points. The points of all layers are then connected vertically by polylines, the number of resulting vertical polylines corresponding to the resolution, or the number of points per layer of the model. The polylines are then divided into sections along the Z-axis, which are represented as points to which data relating to the printhead's movements during printing are assigned. Preferably, the polylines are segmented along the Z-axis such that the number of points for each layer corresponds to the resolution.Assuming there are 100 vertical polylines, the polylines are segmented so that 100 points are created per layer. The printer's path is then determined by selecting the first, lowest point of the first polyline, then the second point of the second polyline (which is slightly higher along the Z-axis), then the third point of the third polyline, and so on. This determines the printer's path along the vertical polylines. Only one point in the model is used at each Z-height; the rest are ignored.

[0019] According to a further embodiment of the ceramic printing process according to the invention, to produce smoothed and / or recessed areas, the desired area is projected onto the 3D model of the urn to be produced, and all points arising during the segmentation of the 3D model and located in the area of ​​the area are offset in the direction of the interior of the urn before the direction vectors are assigned to the points. If the area of ​​the area is to project outwards, the points located in the area of ​​the area of ​​the area are offset outwards. In this process, the shell layer can first be thickened in the area of ​​the desired area, whereby all points of the shell layer that pass through the thickened volume are then offset in the direction of the interior of the urn or outwards.The points of the mantle layer are then assigned travel paths of the printhead during the printhead process by determining a direction vector for each point and assigning it to the point that specifies the travel path of the printhead for that point in the horizontal XY plane and the vertical Z direction.

[0020] This embodiment is used to produce smoothed and / or recessed free surfaces. First, the CAD model is decomposed into individual horizontal layers as previously described. These layers are then divided into discrete sections and represented as points. The desired free surface is then projected onto the base body. All existing patterns are removed and replaced by the selected free surface on the base body. To achieve this, the desired free surface can first be extruded or thickened. Then, all points of the urn body that pass through this extruded or thickened volume are moved in the direction of the desired free surface.

[0021] In addition to data relating to the printhead's travel paths, data concerning material feed via the printhead can also be assigned to the points. Furthermore, additional data, such as printhead speed, extruder temperature, etc., can be assigned to the points.

[0022] According to a further embodiment of the invention, to produce the upper rim of the urn, data relating to the material feed are assigned to the points in at least the uppermost layer of the urn's surface such that the material feed is incrementally reduced to zero during the production of the upper rim. In particular, the data relating to the printhead's travel paths are selected such that the printhead no longer moves in the Z-axis direction. During the production of the upper rim, a change thus occurs from vase-shaped or spiral printing to a horizontal line, with the extrusion of the ceramic material or the material feed being gradually reduced to zero. This results in a visually horizontal upper edge without any visible break-off edge in the last layer.

[0023] Similarly, to produce a first layer on the bottom of an urn, data regarding material feed can be assigned to the points in the first, lowest layer, such that the material feed is incrementally increased from zero to a desired layer thickness during the production of the lowest layer. In particular, the data relating to the printhead travel paths are chosen so that the printhead does not move in the Z-axis direction. In this way, a first layer is produced whose upper surface continuously rises to the layer height, allowing for a perfect transition to the next higher layer.

[0024] Finally, to carry out the printing, the control file can be sent to a 3D printer with a print head and an extruder, whereby the 3D printer prints an urn from a ceramic material based on the control file.

[0025] For further advantageous embodiments and details, reference is made to the following description of exemplary embodiments with reference to the drawings. The drawing shows: Fig. 1. A schematic view of an urn to be manufactured, made of a ceramic material, in front view. Fig. 2 the urn out Fig. 1 after dividing into layers, that is, after slicing, Fig. 3 a representation of the urn made of Fig. 2. Viewed from above after segmentation of the layers, Fig. 4. A perspective view showing the points created during segmentation with their associated vectors. Fig. 5 a perspective representation of the urn as a polyline, Fig. 6. A perspective view of the urn to be produced after segmentation with vertical polylines. Fig. 7 Another perspective view of the urn to be produced after segmentation with polylines, Fig. 8 a representation of a heart-shaped open space, Fig. 9 a target object for the open space to be projected according to Fig. , Fig. 10 the target object with a thickened free area, Fig. 11 the target object with inwardly recessed open space, Fig. 12. The finished urn is shown in section as a continuous polyline. Fig. 13 an urn produced in vase mode according to the invention without the last, uppermost layer as a front view, Fig. 14 the representation from Fig. 13 additionally the last, top layer, and Fig. 15 the urn out Fig. 14 shown as a polyline in perspective view.

[0026] In the Fig. Figure 1 shows a front view of an urn that is to be manufactured from a ceramic material using a ceramic printing process according to the invention. The urn is not rotationally symmetrical, but has a shape that deviates from this, as shown, among other things, in the following. Fig. 5 and Fig. 6 is recognizable.

[0027] To carry out the process, a digital CAD model of the urn to be produced is first created. This can be done with special 3D modeling programs, or alternatively, ready-made models can be downloaded from the internet.

[0028] The finished CAD model is then loaded into special software called "slicing software." In the slicing software, a control file, specifically a G-code file, is generated for a 3D printer based on the CAD model. This file controls the movements of the 3D printer's print head, its speed, and the material feed via the extruder. To do this, the CAD model is first sliced ​​into many thin horizontal layers, as shown in... Fig. Figure 2 indicates that the urn is divided into five layers, S1 to S5. The height of the layers can be specified in the slicing software.

[0029] In a second step, the slicing software divides / segments the individual layers S1 to S5 into discrete sections and displays them as points. The resolution, or the number of points per layer, can also be specified by the user of the slicing software. In this case, the resolution, i.e., the number of points per layer, is 100. Fig. Figure 3 shows such a segmented model of the urn.

[0030] In a third step, the slicing software determines a direction vector for each point, which specifies the travel path of the print head in a horizontal XY plane and in the vertical Z direction of rotation for that point. According to the invention, the control file is created in such a way that at least the outermost layer of the urn to be produced is printed using so-called vase printing, in which the print head of a 3D printer is moved incrementally in the Z-axis direction.

[0031] In the Z-axis direction, this is done taking into account the layer height and the number of points per layer. In the XY plane, the direction vector is determined by the position of the current point A on the respective layer n and the point B directly above it in the subsequent layer n+1.

[0032] In the present example, the direction vectors are as follows, assuming a resolution of 100 and a layer height of 2 mm, according to the following parameters: ▪ Layer height: 2 ▪ Resolution or number of points per layer: 100 ▪ i... Point iterator on each layer (1 to 100) ▪ A... Point on layer (n) ▪ B... Point on layer (n + 1) ▪ z: Z-position Ai(z)Bi(z)→=(00SchickheightResolution*i)

[0033] For the 27th point of the lowest, i.e., first layer, the coordinates of the direction vector in the Z-axis direction are thus: A27(z)B27(z)→=(002100*27)=(000.54)

[0034] The coordinates of the XY plane are given by the following equation: Ai(XY)Bi(XY)→=(Bi(x)Bi(y)0)−(Ai(x)Ai(y)0)

[0035] In other words, the coordinates of point A in the bottom layer are subtracted from the coordinates of the points 3 above it in the layer above.

[0036] For point A27, the direction vector of the XY plane is given as an example: A27(XY)B27(XY)→=(1.2430.9440)

[0037] The total direction vector for point A27 to point B27 is obtained by addition as follows: A27B27→=(1.2430.9440)+(000.54)=(1.2430.9440.54)

[0038] This direction vector is now added to the position data of point A27 and used as an instruction for the 3D printer regarding the print head's movement path at point A27. This is done for the points of all layers. A section of the vector image for the points is shown in the... Fig. 4 shown.

[0039] The Fig. Figure 5 shows a corresponding perspective view of the urn to be manufactured as a polyline. It can be seen that the polylines are laid on top of each other in a spiral pattern, and thus the layers are laid on top of each other in a spiral pattern, so that no visible seam is formed.

[0040] To further improve the quality of the ceramic print of an urn with regularly repeating curves, a slightly modified mode can be used, the so-called modified vase mode.

[0041] Steps 1 and 2 are performed identically to the vase mode.

[0042] The superimposed points of all layers are then connected vertically by polylines P. The number of resulting vertical polylines P corresponds to the resolution or the number of points per layer of the 3D printer (see Fig. 6).

[0043] The polylines P are now divided into segments in the Z-axis direction, and these segments are represented as points to which data relating to the printhead's travel paths are assigned. This is done in such a way that the number of points in the Z-axis direction per layer to be produced is exactly the same as the resolution, that is, the number of points per layer in the circumferential direction of the layer to be produced. If the resolution is 100, then polylines are segmented into 100 stacked points per layer.

[0044] The total number of individual steps in the Z-axis direction is calculated as follows: Height steps Z-axis direction = Object height / [(Number of layers - 1) * Resolution]

[0045] Assuming the following parameters: • Height of the object: 8 mm • Layer height: 2 mm • Number of layers: 5 (4 plus bottom layer) • Resolution: 100 points. The height of the steps in the Z-axis direction and the total number of steps in the Z-axis direction are calculated as follows: • Step height in Z-direction = 8 / [(5 - 1) * 100] = 0.02 mm • Total number of steps in the Z direction = 8 / 0.02 = 400

[0046] Now, the points along the polylines are determined in ascending Z-height. This means that the first, lowest point of the first polyline is selected, then the second point of the second polyline, which is one step higher in the Z-axis direction (here 0.02 mm), is selected, then the third point of the third polyline, which is again one step higher (0.02 mm) than the second point, is selected, and so on. Thus, only one point is used in the model at each Z-height; the rest are ignored. This results in a spiral arrangement of points that runs from the bottom to the top of the object / urn, as shown in the... Fig. 7 is shown.

[0047] An urn, especially one intended to be produced using the vase mode described above, can also be provided with smoothed and / or recessed areas. To do this, a simple vase mode is first applied, as previously described, to create a control file for the urn without any recessed areas. Then, in the slicing software, the desired recessed area, in this case a heart shape, is defined, as shown in the... Fig. As shown in section 7, the pattern is projected onto the urn body. All existing patterns are removed and replaced by the selected free space on the target object, i.e., the urn, as shown in [reference]. Fig. 9 is shown, replaced.

[0048] For this purpose, the desired free area is first extruded or thickened, as is done in the Fig. 10 is shown, and all points of the urn body that pass through this volume 3 are again shifted in the direction of the desired free space towards the interior of the target object, that is, the urn, as shown in Fig. Figure 11 shows the resulting body. Fig. 12 is represented as a continuous polyline.

[0049] The first and last layers of the outer surface play a special role in printing.

[0050] In all cases described above, the last layer corresponds to the topmost or last layer to be produced in the 3D model and should be completely horizontally aligned in the XY plane.

[0051] The Fig. Figure 13 shows the urn body in a front view when produced solely in vase mode. The top layer shown here is not horizontally oriented. To create the upper edge of the urn, data regarding material feed is assigned to the points of at least the upper mantle layer such that the material feed is incrementally reduced to zero during the production of the upper edge. The data is chosen with respect to the printhead travel paths so that the printhead does not move in the Z-axis direction. In other words, the printhead moves only horizontally during the production of the last layer, but the material feed is reduced to zero during this process. As a result, the upper edge is horizontal, as shown in the Fig. 14 and Fig. 15 is shown.

[0052] Similarly, the first mantle layer, which is applied to the manufactured base of an urn, can be produced by moving the print head only in a horizontal direction, while incrementally increasing the material feed from zero to the desired layer height during the production of the bottom mantle layer of the urn.

Claims

[1] Ceramic printing process for the production of urns from ceramic materials using 3D printing, in which a CAD model of the urn to be produced is created and a control file, in particular a G-code file, is produced on the basis of the CAD model for a 3D printer, which controls the travel paths of a print head of the 3D printer, the speed of the print head and the material feed via an extruder of the 3D printer by segmenting the produced CAD model into sections, representing the sections as points and assigning data relating to the travel paths of the print head during printing to the individual points, characterized by , that the control file is created in such a way that at least the outermost layer of the urn to be produced is printed in vase mode, in which the print head of a 3D printer is moved incrementally in the Z-axis direction. [2] Ceramic printing process according to claim 1, characterized by, that the CAD model is broken down into individual horizontal layers and the layers are divided into discrete sections and represented as points. [3] Ceramic printing process according to claim 2, characterized by , that for each point a direction vector is determined and assigned to the point, which specifies the travel path of the print head in the horizontal XY plane and the vertical Z-axis direction for the point. [4] Ceramic printing method according to claim 3, characterized by , that for each point the direction vector in the horizontal XY plane is determined by the position of the current point (A) on the respective layer (n) and a point directly above it (B) on the layer above (n+1), and in the vertical Z-axis direction the direction vector is determined taking into account the layer height and the number of points per layer. [5] Ceramic printing process according to claim 4, characterized by, that the direction vectors in the vertical Z-axis direction are determined as follows: Ai(z)Bi(z)→=(00SchickheightResolution*i) where the resolution is the number of points per layer, i is the point iterator on the respective layer, A is the point on layer (n), B is the point on layer (n+1), and z is the Z-position. [6] Ceramic printing process according to claim 4 or 5, characterized by , that the direction vectors in the horizontal XY plane are determined by subtracting the XY coordinates of a point A on a layer (n) from the XY coordinates of the corresponding point B from the layer (n+1), where i is the point iterator on the respective layer. [7] Ceramic printing process according to any one of claims 2 to 6, characterized bythat the superimposed points of all layers are vertically connected by polylines, where the number of polylines corresponds to the resolution and thus the number of points per layer, and that the polylines are evenly divided into sections in the Z-axis direction and the sections are represented as points to which data relating to the travel paths of the print head for printing are assigned. [8] Ceramic printing process according to claim 7, characterized by , that the number of sections per layer corresponds to the resolution, and that the data relating to the travel path are determined in such a way that the polylines are traversed one after the other, whereby, starting from a point on a polyline with the lowest Z-height, the print head always moves to the next highest point on the following polyline in the Z-axis direction. [9] Ceramic printing process according to any one of claims 2 to 8, characterized by, that to produce smoothed and / or recessed free surfaces, the desired free surface is projected onto the 3D model of the urn to be produced, and that all points arising during the segmentation of the 3D model and lying in the area of ​​the free surface are offset in the direction of the interior of the urn before the direction vectors are assigned to the points. [10] Ceramic printing process according to claim 9, characterized by , that in the area of ​​the desired free space the mantle layer is first thickened and all points of the mantle layer that pass through the thickened volume are offset in the direction of the interior of the urn, and that the points of the mantle layer are assigned travel paths of the print head during printing. [11] Ceramic printing process according to any one of the preceding claims, characterized by, that in addition to the data relating to the printhead's travel paths, data relating to the material feed via the printhead are also assigned to the points. [12] Ceramic printing process according to claim 11, characterized by , that, for the production of the upper edge of the urn, data relating to the material supply are assigned to the points in at least the uppermost mantle layer such that the material supply is incrementally reduced to 0 during the production of the upper edge of the urn, wherein, in particular, the data relating to the travel paths of the printhead are chosen such that the printhead does not move in the Z-axis direction. [13] Ceramic printing process according to claim 11 or 12, characterized by, that to produce a first mantle layer on the bottom of an urn, data regarding the material supply are assigned to the points in the first lowest mantle layer such that the material supply is incrementally increased from 0 to a desired layer thickness during the production of the lowest mantle layer of the urn, wherein, in particular, the data regarding the travel paths of the printhead are chosen such that the printhead does not move in the Z-axis direction. [14] Ceramic printing process according to any one of the preceding claims, characterized by , that the control file is transmitted to a 3D printer with a print head and an extruder, and the 3D printer prints an urn based on the control file from a ceramic material.

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