Porous hollow chamber structure

Abstract

A porous hollow chamber structure produced by an additive manufacturing process, characterized in that it consists of a three-dimensional lattice of different rows of composite modules, wherein each module consists of two polyhedra and each polyhedron represents fourteen-sided truncated hexagonal trapezohedra consisting of two hexagonal faces (1) and twelve pentagonal faces (10), and the row of modules running from the bottom to the top has continuous hexagonal openings (22), as well as the row of modules running from the left side to the right side having hexagonal openings (3, 30) perpendicular to the direction of travel of the row, and the row of modules running from the front to the back has hexagonal openings (3, 30) perpendicular to the direction of travel of the row.30) and each module has at least one hexagonal wall (21) perpendicular to the direction of travel of the series, and each module has two pentagonal openings (11, 12) of the largest pentagonal faces per polyhedron, wherein the pentagonal openings (11, 12) of a module are arranged at right angles to each other along the axis of the direction of travel of the series, and that a series consists of one module and at least one polyhedron in solid material.

Description

[0001] The invention relates to a porous hollow chamber structure produced by an additive manufacturing process.

[0002] Technical foams made from sintered materials are used in industry. They are used in many technical fields where they are superior to solid materials. Their production is complex and therefore expensive. New additive manufacturing processes, such as the three-dimensional printing of foam-like structures, appear promising.

[0003] Sintered closed-cell and open-cell porous foams exhibit irregularities in their wall thickness and structure, making their properties under force increasingly unpredictable. Particularly when exposed to heat, such as in porous burners, which are open-cell porous ceramic foams, this leads to rapid burner wear. Commonly sintered open-cell foams have additional weaknesses in that they consist primarily of struts of uneven thickness.

[0004] In three-dimensional printing, structures called infill are used to fill an object to be manufactured. This is intended to save material and enable higher quality and resilience. However, these structures generally have the following disadvantages: Two-dimensional structures that are used have their highest stability only along the Z-axis of production. The X and Y axes have the lowest stability. Material-saving, three-dimensional infill structures, which theoretically represent synthetic technical foams, often have flat horizontal surfaces or struts that do not rest on a substrate and are therefore difficult to produce using common processes such as three-dimensional printing. This is because extrusion always requires a substrate, be it the print bed or already extruded material.If the horizontal surfaces are omitted, sufficient stability can no longer be guaranteed due to the structure's too simple geometry.

[0005] DE102015202277A discloses a process for producing ceramic foams in which a slurry consisting of a special mixture is mechanically processed. The resulting liquid foam is then dried in a mold under the exclusion of air and then sintered in an open furnace atmosphere at 1400 to 2000 degrees Celsius. A disadvantage of this method is that a uniform foam structure cannot be achieved.

[0006] US20160346999A1 discloses a method for three-dimensionally printing a two-dimensional infill structure at high speed. The disadvantage of this method is that it is two-dimensional and therefore stable only along the Z-axis.

[0007] US20190240734A1 discloses a geometric structure as infill within the shell of a three-dimensionally printed object. The infill structure is specifically designed to allow the leaching of a binding agent through porosity. A disadvantage of this structure is that, due to its elasticity, it is unsuitable as a supporting infill within a rigid object shell if the object shell is to remain intact under the action of force. Another disadvantage is that, due to the tapered angles of the chambers, there is very little or no substrate for extrusion at the highest point of each chamber.

[0008] In July 2019, a master's thesis by Catarina Maria Moreira da Silva of the Universidade do Porto, entitled "3D printing of gyroid structures for superior structural behavior," was published. It shows that the three-dimensional gyroid infill structure tested there unfortunately has the property of collapsing within it when excessive force is applied, causing permanent deformation. It also points out the difficulty of printing the structure in three dimensions at all.

[0009] WO2014 / 150503 A1 describes a computer-generated geometric structure that can be manufactured as a ceramic filter using additive manufacturing processes. A disadvantage of this structure, however, is that it is not optimally designed for common additive manufacturing processes. The potential advantages of digitally modeled cell homogeneity and 3D printing are discussed, but the feasibility of the structure in common 3D printing processes, which often have specific requirements for the geometry of an object, is not specifically addressed. Furthermore, depending on the axis of alignment, the circular openings are unsuitable for common 3D printing processes such as fused deposition modeling, unless there is sufficient substrate for the material layers. Another disadvantage is that Fig. 1-4 show a two-dimensional arrangement of the individual polyhedra. However, no three-dimensional structure suitable as an infill structure. Fig. Although Figure 9 shows a three-dimensional embodiment, no clear assignment of the surfaces to a repeatable three-dimensional structure is discernible. Furthermore, not only walls but also struts within the structure are described, which results in the structure forming a one-dimensional foam structure and thus potentially less mechanically resilient.

[0010] The invention defined in claim 1 is therefore based on the object of providing an alternative to the technical foams previously produced in industry using established additive manufacturing processes, while avoiding the disadvantages outlined above.

[0011] This problem is solved by the features listed in patent claim 1.

[0012] The advantages achieved by the invention lie in the fact that, instead of the previous cost-intensive and complex production of technical foams, conventional, established manufacturing processes can be used. In contrast to conventional infill structures, this one exhibits more uniform stability along its three axes. In contrast to three-dimensional infill structures with consistent, regular cell rows, greater stability is achieved here, even with open cells, through the different arrangement of the cells within the overarching regular lattice. Instead of high elasticity, high rigidity is achieved, which leads to material savings and lower weight. The more uniform force and heat distribution through walls prevents hairline cracks and signs of wear, as well as material fatigue, better than is the case with struts.Three-dimensional printing of the invention according to claim 1 enables more uniform production compared to the processes previously used in industry for producing technical foams, thus providing better control over the object properties. Orthogonal differences in wall thickness and density of the invention according to claim 1 can thus be specifically introduced, for example, to reinforce areas subject to particularly high mechanical stress. In contrast to previous technical foams and three-dimensional infill structures, the invention is intended to simultaneously enable better cleaning or rinsing due to its large openings, as well as a high structural density and thus a particularly large surface area, which further expands its areas of application.

[0013] The invention will be explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a fourteen-sided truncated hexagonal trapezohedron consisting of two hexagonal faces and twelve pentagonal faces. Fig. 2 the polyhedron Fig. 1 in side view. Fig. 3 the polyhedron Fig. 1 in top view. Fig. 4 the polyhedron Fig. 1 in cavalier projection. Fig. 5 Module one doubled and joined together to form a row in front view with pentagonal openings arranged at right angles. Fig. 6 the module two double and joined to form a row in front view with pentagonal openings arranged at right angles. Fig. 7 Module one doubled and joined together to form a row in cavalier perspective with pentagonal openings arranged at right angles. Fig. 8 the module two double and joined together to form a row in cavalier perspective with pentagonal openings arranged at right angles. Fig. 9 the porous hollow chamber structure in its basic form in front view with opposite orientations of the module rows. Fig. 10 the porous hollow chamber structure in its basic form in side view with opposite orientations of the module rows. Fig. 11 the porous hollow chamber structure in its basic form in plan view with opposite orientations of the module rows. Fig. 12 the porous hollow chamber structure in its basic form in cavalier projection with opposite orientations of the module rows. Fig. 13 the cross-section through the porous hollow chamber structure in its basic form in front view with opposite orientations of the module rows. Fig. 14 Example of the porous hollow chamber structure as a freestanding object.

[0014] Fig. 1 shows a polyhedron, a so-called fourteen-sided truncated hexagonal trapezoid consisting of two hexagonal faces 1 and twelve pentagonal faces 10.

[0015] Fig. 2 shows the polyhedron from Fig. 1 in side view with the hexagonal surfaces 1 and the pentagonal surfaces 10.

[0016] Fig. 3 shows the polyhedron from Fig. 1 in plan view with the hexagonal surfaces 1 and the pentagonal surfaces 10.

[0017] Fig. 4 shows the polyhedron from Fig. 1 in cavalier projection with the hexagonal surfaces 1 and the pentagonal surfaces 10.

[0018] Fig. 5 shows the polyhedron from Fig. 1 doubled to form a single module, and this doubled as a combined row in front view with pentagonal openings 11, 12, 13, 14 arranged at right angles along the central axis of the row. This is the module that runs as a row from the bottom to the top.

[0019] Fig. 6 shows the polyhedron from Fig. 1 doubled to form a single module, and this doubled as a combined row in front view with pentagonal openings 11, 12, 13, 14 arranged at right angles along the central axis of the row. This is the module that runs as a row from left to right.

[0020] Fig. 7 shows the polyhedron from Fig. 1 doubled together to form a module and this doubled as a combined row in cavalier perspective with pentagonal openings 11,12,13,14 arranged at right angles along the central axis of the row, as well as the hexagonal openings 3.30.

[0021] Fig. 8 shows the polyhedron from Fig. 1 twice assembled to form a module and this twice as a combined row in cavalier perspective with pentagonal openings 11,12,13,14 arranged at right angles along the central axis of the row. The hexagonal walls 20,21 required for production, horizontal to the running direction, and the hexagonal openings 3.30, perpendicular to the running direction, can be seen.

[0022] Fig. 9 shows the porous hollow chamber structure in front view with opposite running directions of the rows running from front to back and the rows running from left to right,

[0023] Fig. Figure 10 shows the porous hollow chamber structure in side view with opposite directions of the rows running from front to back and the rows running from left to right.

[0024] Fig. 11 shows the porous hollow chamber structure in its basic form in top view.

[0025] Fig. Figure 12 shows the porous hollow chamber structure in cavalier projection with opposite directions of the rows running from front to back and the rows running from left to right.

[0026] Fig. 13 shows the cross-section through the porous hollow chamber structure in front view with opposite running directions of the rows running from front to back and the rows running from left to right.

[0027] Fig. 14 shows an example of the porous hollow chamber structure as a freestanding object in cylindrical shape. List of reference symbols 1 hexagonal surfaces 3 hexagonal opening 4 pentagonal opening 10 Pentagonal area 11 Pentagonal opening 12 Pentagonal opening 13 Pentagonal opening 14 Pentagonal opening 20 hexagonal wall 21 hexagonal wall 22 Hexagonal opening 30 hexagonal opening

Claims

[1] A porous hollow chamber structure produced by an additive manufacturing process, characterized bythat it consists of a three-dimensional grid of different rows of assembled modules, wherein each module consists of two polyhedra and each polyhedron represents fourteen-sided truncated hexagonal trapezoidal surfaces consisting of two hexagonal faces (1) and twelve pentagonal faces (10), and the row of modules running from the bottom to the top have continuous hexagonal openings (22), and the row of modules running from the left side to the right side have hexagonal openings (3, 30) perpendicular to the direction of travel of the row, and the row of modules running from the front to the back have hexagonal openings (3, 30) perpendicular to the direction of travel of the row and each have at least one hexagonal wall (21) per module horizontal to the direction of travel of the row, and each module has two pentagonal openings (11, 12) of the largest pentagonal faces per polyhedron, wherein the pentagonal openings (11,12) of a module are arranged at right angles to each other along the axis of the running direction of the row and that a row consists of a module and at least one polyhedron in solid material.

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