Multi-material liquid based 3D printing for full shoe manufacturing

Abstract

To provide an improved 3D printing method.SOLUTION: A method of printing a three-dimensional object comprises at least: a step of preparing at least first and second printing materials separated in at least a first material tank and a second material tank; a step of preparing a build platform; a first printing step of printing the object at least partially onto the build platform using the first printing material; a cleaning step of cleaning the object from the first and / or second printing material; and a second printing step of printing the object at least partially onto the build platform using the second printing material.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a method for printing a three-dimensional object by providing at least first and second printing materials separated into at least a first material reservoir and a second material reservoir. [Background technology]

[0002] In the 3D printing industry, printing methods using digital light processing (DLP) and photopolymerization are often limited to the use of only one material per printing job, thereby limiting the overall material usage in traditional 3D printing. Parts printed from only one material often lack the functional and / or aesthetic requirements needed for more complex applications. Printing methods that use multiple materials per printing job are often cumbersome and costly due to the meticulous handling and assembly required. Additionally, typical 3D printing methods often result in wasted excess material, which is not only costly but also reduces the sustainability of manufacturing. Another drawback of traditional printing methods is the management of material residues that remain on the product and degrade the quality of the final product.

[0003] Generally, conventional methods either limit material use or the printing process is unnecessarily cumbersome and meticulous, which is inconvenient. These methods also result in wasted excess material and leave material residue on the product. Thus, there is a need for improved 3D printing methods.

[0004] In view of the foregoing, there is a need for improved 3D printing methods. It is therefore an object of the present invention to overcome some or all of the deficiencies of the prior art. Summary of the Invention

[0005] The above object is achieved at least in part by the subject matter of independent claim 1. Preferred embodiments are the subject matter of the dependent claims, and those skilled in the art will find hints to other preferred aspects of the invention from the entire disclosure of this application.

[0006] One aspect of the present invention relates to a method for printing a three-dimensional object, the method including at least the steps of preparing at least first and second printing materials separated into at least a first material tank and a second material tank; preparing a build platform; a first printing step of printing an object at least partially on the build platform using the first printing material; a cleaning step of cleaning the object from the first and / or second printing material; and a second printing step of printing an object at least partially on the build platform using the second printing material.

[0007] This method can be particularly useful in applications where different portions of a finished object require different properties, such as color, strength, or heat resistance. For example, a manufacturer may use a flexible material for the core of a part and a more sturdy, colorful material for the outer layers to enhance aesthetics and functionality. This method enables high precision in multi-material 3D printing, reduces material waste, and improves the efficiency of the printing process by cleaning the object between steps, which helps maintain the quality and integrity of the finished product. Printing the object at least partially on the build platform can also include printing on a partially printed object attached to the build platform.

[0008] Another aspect of the present invention is realized when the cleaning step includes at least the steps of providing one or more cleaning tanks containing cleaning liquid, providing one or more air knives, providing one or more standing waves of the cleaning liquid, cleaning the object by exposing the object to the one or more standing waves of the cleaning liquid, and drying the cleaned object by exposing the cleaned object to one or more air knives.

[0009] Such cleaning steps provide a highly efficient means of ensuring that each layer of a printed object is free of contamination before the next material is applied, which is important for maintaining the structural integrity and aesthetic quality of the final product. For example, such thorough cleaning can prevent materials from intermixing, which could otherwise impair functionality and / or aesthetics. The combination of standing waves and air knives provides thorough yet gentle cleaning, making it suitable for complex shapes and delicate details.

[0010] Another aspect of the present invention is achieved when the cleaning step instead includes at least the steps of: preparing one or more cleaning tanks containing a cleaning liquid, at least one of the cleaning tanks being an ultrasonic cleaning tank configured for ultrasonic cleaning and dedicated to ultrasonic cleaning; preparing one or more air knives; cleaning the object by immersing the object in the ultrasonic cleaning tank; and drying the cleaned object by exposing the cleaned object to one or more air knives.

[0011] Such cleaning steps can be highly beneficial in applications requiring high levels of purity and precision. Ultrasonic cleaning ensures thorough removal of residues and contaminants. This method not only improves the structural and surface integrity of the printed object, but also improves the bonding and layering of different materials in subsequent printing steps due to less contaminated material within the layers, thereby leading to a higher quality and more reliable final product.

[0012] The method for printing a three-dimensional object may be further improved if at least one of the material tanks and / or at least one of the washing tanks is horizontally movable.

[0013] This feature particularly improves the efficiency and flexibility of the printing process. For example, in large-scale manufacturing environments where multiple objects or object parts need to be printed simultaneously or sequentially, the ability to move the tank horizontally can reduce the time it takes to change materials or initiate a cleaning cycle. This adaptability is particularly advantageous in production lines that require quick changeover between different types of materials or frequent cleaning of objects. Tank mobility also leads to improved space management within the printing facility, optimizing the overall workflow and reducing operational downtime.

[0014] A further improvement of the method is achieved if the tank is placed on a rotatable disk.

[0015] Such an arrangement proves particularly beneficial in environments where rapid production and high throughput are important. For example, in industrial applications where multiple colors or material properties are required within a short production timeline, the rotatable disk allows for fast changeover between tanks, thereby reducing downtime. Additionally, this method improves the accuracy of material processing steps, ensuring the correct material or cleaning solution is immediately available at the exact time it is needed.

[0016] Such a method can be further improved if at least one washing tank is disposed between the printing material tanks.

[0017] Such a configuration is advantageous in situations where multiple material properties are critical to product functionality. For example, centrally locating the wash tank helps maintain high-quality prints by ensuring each material adheres properly without contamination from previous materials. Additionally, this configuration optimizes workflow by minimizing the transfers required between different stages of the printing process, leading to faster production and reduced operating costs.

[0018] The method can be further improved if the build platform is vertically and horizontally movable.

[0019] Such vertically and horizontally movable build platforms can be beneficial in the production of complex, multi-layer objects where precise layer alignment is required for structural integrity and functional performance. This adaptability not only improves the quality of the final product, but also enables the production of more complex shapes that may not be feasible with fixed platforms, thereby expanding the capabilities of 3D printing methods.

[0020] This method is further improved if the build platform consists of a Stewart platform.

[0021] The incorporation of the Stewart platform is ideal for manufacturing contexts requiring high precision. The ability to fine-tune the platform's orientation and position ensures that each layer of a 3D printed object is deposited precisely and in proper registration with respect to the other layers, thereby improving the structural integrity and functional accuracy of the final product. Additionally, such a configuration can accommodate the complex printing trajectories and material deposition patterns necessary to create advanced shapes and structures with high performance and reliability.

[0022] Further improvement is achieved when at least one of the print materials is a liquid photopolymer resin.

[0023] The use of liquid photopolymer resins is advantageous for applications requiring extremely fine and smooth surface finishes. The precision achievable with photopolymer resins exceeds that of many other 3D printing materials, enabling the creation of parts with complex geometries and fine features that are difficult to achieve with traditional materials. Furthermore, photopolymer resins can be formulated with a variety of properties, including different colors, transparencies, and mechanical properties, enhancing the versatility and applicability of 3D printing methods across various industries.

[0024] Further improvements are realized when printing utilizes Digital Light Processing (DLP).

[0025] Using DLP in the 3D printing process is particularly beneficial for creating parts that require high-speed production without sacrificing detail and accuracy. DLP's ability to simultaneously cure entire layers allows for the creation of complex, high-resolution structures more quickly than other printing methods that require more time. In addition, DLP technology can be optimized for use with a wide range of photopolymer resins, allowing for variations in material properties such as flexibility, strength, and opacity, thereby expanding the range and versatility of 3D printing applications.

[0026] Further improvements are achieved when printing is performed by photopolymerization.

[0027] The use of photopolymerization in the 3D printing process offers unique advantages for producing highly detailed, high-precision parts. The ability to precisely control light exposure enables complex designs with smooth surfaces and exquisite detail that may not be achievable with traditional manufacturing methods. In addition, photopolymerization can be used with a wide range of different resins, each offering different mechanical and thermal properties, enabling the production of customized articles tailored to specific functional requirements and environmental conditions.

[0028] Further improvements are obtained when the photopolymerization is achieved by UV light.

[0029] The use of UV light for photopolymerization in 3D printing systems, such as those using DLP, offers several advantages. First, UV light can cure certain resins very rapidly, improving the speed of the printing process, which is important for high-throughput production. Furthermore, the use of UV light allows for very fine control over the curing process, enabling the production of parts with extremely fine detail and high dimensional accuracy. This method also supports the use of a wide range of UV-curable resins, allowing for the customization of material properties to suit specific applications.

[0030] Further improvements are achieved when the first and second print materials have different mechanical properties.

[0031] Such an approach can be particularly advantageous when components often require regions of different stiffness and flexibility within a single part to achieve optimal performance and safety. The ability to print with materials with diverse mechanical properties in a single print session also improves product design and innovation, enabling the production of parts that are both lightweight and durable, or stiff in some areas and flexible in others. This not only simplifies the manufacturing process by reducing the need to assemble multiple parts, but also opens new possibilities for designing more complex, functionally integrated products.

[0032] The method is further improved when the first material has a Shore A hardness in the range of 70-80.

[0033] Materials with a Shore A hardness of 70-80 are considered suitable for applications requiring a balance between flexibility and structural strength. This level of hardness is suitable for parts that must withstand physical stress and deformation without fracture. Using such materials in 3D printing makes it possible to create parts that can withstand bending and flexing while still maintaining their shape and integrity. This property is particularly beneficial when components must frequently endure dynamic stresses and still provide reliable performance.

[0034] Further improvement is obtained when the first material has an elongation at break in the range of 240% to 360%.

[0035] Such elongation capability makes the first material particularly suitable for producing parts that must withstand extensive deformation under load without tearing or that undergo frequent stretching. The combination of a Shore A hardness of 70-80 and a high elongation at break provides a material that is not only tough and tear-resistant, but also highly adaptable to dynamic mechanical conditions.

[0036] This can be further improved if the first material has a tear strength in the range of 20-30 kN / m.

[0037] The combination of a moderate Shore A hardness (70-80), a high elongation at break (240%-360%), and a considerable tear strength (20-30 kN / m) makes the first material suitable for manufacturing components exposed to harsh conditions. The material's properties ensure that such components can function reliably without failure, thereby providing safety and a long service life.

[0038] The method can also be improved if the second material has a Shore D hardness in the range of 68-74.

[0039] A second material with such a level of hardness is suitable for applications requiring high structural integrity and resistance to mechanical stress and deformation. For example, the combination of the flexibility of the first material and the hardness of the second material allows for the production of a resilient yet durable composite object that optimizes performance across a variety of operational demands.

[0040] Further improvement is achieved when the second material has a tensile modulus in the range of 1000 MPa to 1200 MPa.

[0041] A tensile modulus in this range makes the second material suitable for structural applications where stiffness and the ability to support loads without excessive deformation are important. Such applications benefit from the material's high stiffness, ensuring that structural components maintain their shape and functionality under mechanical stress, contributing to the overall integrity and safety of the system. Such a material, with a Shore D hardness of 68-74 and a tensile modulus of 1000-1200 MPa, complements the more flexible first material, allowing for a balanced combination of properties in the final printed object.

[0042] Further improvement is obtained when the second material has an elongation at break greater than 50%.

[0043] Such properties may make the second material suitable for components that must withstand both static and dynamic stresses. The combination of a Shore D hardness of 68-74, a tensile modulus in the range of 1000-1200 MPa, and an elongation at break greater than 50% provides a robust material profile suitable for producing parts expected to perform reliably under varying operating conditions. This ensures that the part can support loads while accommodating movement and small deformations.

[0044] Examples of first and second materials may include commonly known printing materials such as EPU43, EPU44, EPU45, EPU46, LOCTITE® 3D IND405 Clear, RPU70, UMA90, and / or other suitable materials. The choice of material may also depend on the properties desired, for example, using polyamide (PA) to achieve toughness and / or rigidity, or thermoplastic polyurethane (TPU) to achieve varying hardness, resilience, and damping.

[0045] To further improve the method, the fill level of the printing material in the material tank is controlled by a control means to maintain a constant fill level.

[0046] The ability to maintain a constant fill level in a material tank is beneficial when printing large or complex structures. The control means may include a sensor that monitors the material level and adjusts it by adding material from reserve when the level drops or by stopping addition when an optimal level is reached. This automated adjustment helps achieve a high degree of precision in the final product, optimizes material usage, and reduces waste, thereby improving the overall efficiency and cost-effectiveness of the manufacturing process.

[0047] This can be further achieved if the method includes estimating tank refill amounts based on the volume of the printed layer.

[0048] Estimating tank refill amounts is advantageous for maintaining efficiency and material consistency in continuous or high-volume printing operations. Being able to accurately calculate and replenish the exact amount of material used per layer helps avoid both shortages, which can pause or stop the printing process, and overfilling, which can result in wasted or spilled material. This approach not only improves the accuracy of the printing process, but also optimizes material usage, reducing overall production costs and minimizing waste.

[0049] To further improve this method, the filling level of the printing material in the material tank is controlled by the control means to be in the range of 0.5 mm to 4 mm, preferably in the range of 1 mm to 2 mm.

[0050] Maintaining such a fill level range is especially important in applications requiring extremely high precision and uniformity of material deposition. The specified range ensures that the printing mechanism always has optimal access to the material. In addition, such precise control helps maintain a constant viscosity and temperature of the material. Through improved control mechanisms, such methods contribute to the reliability and efficiency of the printing process.

[0051] To further improve this method, the fill level of the printing material in the material tank is controlled by a control means to be the minimum amount required to print one layer.

[0052] Such methods are beneficial in high-precision manufacturing processes where material efficiency and layer quality are paramount. Maintaining the minimum required amount for each layer minimizes the risk of material degradation due to long-term exposure to environmental factors and reduces overall material costs by avoiding excessive use. This approach not only improves the sustainability of the printing process by conserving resources, but also ensures that each layer is consistently printed with fresh material, which can improve the structural integrity and resolution of the final product. This material management helps achieve the high standards required in advanced manufacturing applications.

[0053] A further improvement of the method is achieved if the control means comprises an overflow dam.

[0054] The inclusion of an overflow dam is advantageous in 3D printing mechanisms: by preventing overfilling, the overflow dam helps maintain a consistent flow of material to the printer head, which is necessary to achieve uniform layer deposition. Additionally, it helps reduce material waste by capturing excess that might otherwise spill or be wasted, thereby improving the efficiency and cost-effectiveness of the printing process. The overflow dam can also help maintain a clean and controlled printing environment by suppressing spills and splatter, thereby improving the operational reliability and ease of maintenance of the printing equipment.

[0055] The method may be further improved if the control means comprises a contactless fill level sensor, the sensor comprising an ultrasonic transducer and / or a laser.

[0056] The addition of such kind of sensor provides an improved printing mechanism since fill level monitoring can be seamlessly implemented within the printing mechanism by detecting the fill level with a non-contact sensor, thus enabling the control means to control the fill level of the material tank to maintain a constant level.

[0057] A further improvement of the method is achieved if the control means comprises a weight sensor.

[0058] Such a weight sensor allows the additional possibility of measuring the fill level of a material tank by knowing the total weight of the material inside the tank, which opens up the opportunity to control the fill level even more precisely.

[0059] Another part of the present invention is sporting goods made according to the above method.

[0060] This method of the present invention is well suited to the manufacture of sporting goods, as sporting goods often require materials and manufacturing methods that utilize the parameters described above.

[0061] The present invention includes the following embodiments. [1]. A method of printing a three-dimensional object, comprising: providing at least first and second printing materials separated into at least a first material tank and a second material tank; providing a build platform; a first printing step of printing an object at least partially on a build platform using a first printing material; a cleaning step of cleaning the object from the first and / or second printing materials; a second printing step of printing an object at least partially on the build platform using a second printing material; The method includes at least [2].The cleaning step is providing one or more cleaning tanks containing a cleaning solution; providing one or more air knives; providing one or more standing waves of a cleaning liquid; cleaning the object by exposing the object to one or more standing waves of a cleaning liquid; drying the cleaned object by exposing the cleaned object to one or more air knives; The method according to [1], comprising at least the steps of: [3].The cleaning step is providing one or more cleaning tanks containing a cleaning solution, wherein at least one of the cleaning tanks is a dedicated ultrasonic cleaning tank configured for ultrasonic cleaning; providing one or more air knives; cleaning the object by immersing the object in an ultrasonic cleaning tank; drying the cleaned object by exposing the object to one or more air knives; The method according to [1], comprising at least the steps of: [4]. The method according to one of [1] to [3], wherein at least one of the material tanks and / or at least one of the cleaning tanks is horizontally movable. [5].The method according to one of [1] to [4], wherein the tank is placed on a rotatable disk. [6]. The method according to one of [2] to [5], wherein at least one cleaning tank is disposed between the printing material tanks. [7]. The method according to one of [1] to [6], wherein the build platform is movable vertically and horizontally. [8]. The method according to [7], wherein the build platform comprises a Stewart platform. [9]. The method according to one of [1] to [8], wherein at least one of the printing materials is a liquid photopolymer resin.

[10] . The method according to one of [1] to [9], wherein the printing utilizes digital light processing (DLP).

[11] . The method according to one of [1] to

[10] , wherein the printing is carried out by photopolymerization.

[12] . The method according to

[11] , wherein photopolymerization is achieved by UV light.

[13] . The method according to one of [1] to

[12] , wherein the first printing material and the second printing material have different mechanical properties.

[14] . The method according to

[13] , wherein the first material has a Shore A hardness in the range of 70 to 80.

[15] . The method according to

[13] or

[14] , wherein the first material has a breaking elongation in the range of 240% to 360%.

[16] . The method according to any one of

[13] to

[15] , wherein the first material has a tear strength in the range of 20 to 30 kN / m.

[17] . The method of any one of

[13] or

[14] , wherein the second material has a Shore D hardness in the range of 68 to 74.

[18] . The method according to any one of

[13] to

[17] , wherein the second material has a tensile modulus in the range of 1000 MPa to 1200 MPa.

[19] . The method according to any one of

[13] to

[18] , wherein the second material has a breaking elongation of greater than 50%.

[20] . The method according to one of [1] to

[19] , wherein the fill level of the printing material in the material tank is controlled by a control means so as to maintain a constant fill level.

[21] . The method of

[20] , wherein the method includes estimating tank refill amounts based on the volume of the printed layer.

[22] . The method according to

[20] or

[21] , wherein the filling level of the printing material in the material tank is controlled by the control means so as to be within a range of 0.5 mm to 4 mm, preferably 1 mm to 2 mm.

[23] . The method according to one of

[20] to

[22] , wherein the filling level of the printing material in the material tank is controlled by a control means to be the minimum amount required to print one layer.

[24] . The method according to one of

[20] to

[23] , wherein the control means comprises an overflow dam.

[25] . The method according to one of

[20] to

[24] , wherein the control means comprises a non-contact fill level sensor, the sensor comprising an ultrasonic transducer and / or a laser.

[26] . The method according to one of

[20] to

[25] , wherein the control means comprises a weight sensor.

[27] . Sports equipment manufactured according to the method described in any one of [1] to

[26] .

[0062] Preferred embodiments of the present disclosure will now be disclosed with reference to the accompanying drawings. [Brief explanation of the drawings]

[0063] [Figure 1] 1 is a schematic diagram illustrating a method according to the present invention using a horizontally movable build platform. [Figure 2] 1 is a schematic diagram illustrating a method according to the present invention using a printing reservoir; [Figure 3] FIG. 1 is a schematic diagram illustrating a method according to the present invention using a rotatable disk. [Figure 4]FIG. 1 illustrates a general method for printing three-dimensional objects with high fill levels. [Figure 5] FIG. 1 illustrates a method according to the invention using a lower filling level. [Figure 6] FIG. 1 shows a method according to the invention using an overflow dam. [Figure 7] FIG. 1 shows a shoe with cleats printed by the method according to the present invention. [Figure 8] FIG. 1 shows a shin guard printed by the method of the present invention. [Figure 9] FIG. 1 shows a shoe printed by the method according to the invention. [Figure 10] FIG. 1 shows a shoe sole printed by the method according to the present invention. [Figure 11] FIG. 1 shows a vertically integrated shoe sole printed by the method of the present invention. [Figure 12] FIG. 10 is a schematic diagram of a method according to the present invention, showing a build platform passing through a wash tank after a first printing step. [Figure 13] FIG. 13 is a schematic diagram illustrating the method of FIG. 12, in which the build platform passes through a wash tank after the second printing step. [Figure 14] 1A-1C are schematic diagrams illustrating a method of the present invention, in which a build platform passes through an ultrasonic cleaning tank. DETAILED DESCRIPTION OF THE INVENTION

[0064] In the following sections, a detailed description of the present invention is provided with reference to the accompanying drawings for clarity. The description is for illustrative purposes only and is not intended to limit the scope of the present invention. The same reference symbols throughout the drawings and text represent the same components. The illustrations may not reflect actual size or scale, and the dimensions, proportions, and depictions of elements may be exaggerated for better understanding and visual convenience.

[0065] FIG. 1 shows a printing mechanism according to the present invention for printing a three-dimensional object 1. A build platform 100 is movable horizontally and vertically. The three-dimensional object 1 to be printed is printed on the bottom side of the build platform 100. A first material tank 10 and a second material tank 20 are provided, where the first material tank 10 contains a first printing material (not shown) and the second material tank 20 contains a second printing material (not shown). The build platform 100 can easily switch between the first material tank 10 and the second material tank 20 to print three-dimensional objects from different materials.

[0066] The build platform 100 can seamlessly alternate between the two tanks 10 and 20, enabling the integration of different materials into the three-dimensional object 1. This capability is particularly useful for creating complex objects that require diverse material properties (e.g., hardness, flexibility, color, etc.) in different areas of the final product. Such a mechanism enables improved product functionality and aesthetic quality by incorporating multiple materials into a single object without the need for manual intervention or post-print assembly. This can greatly streamline the manufacturing process for multi-material articles, and material properties can be optimized for specific functional zones within the object. In this embodiment, the printing material can be a liquid photopolymer resin. Printing can utilize digital light processing (DLP). Printing can also be performed by photopolymerization, which can be achieved with UV light.

[0067] 2 shows another printing mechanism according to the present invention for printing a three-dimensional object 1. A build platform 200 is vertically movable. A printing container 30 is positioned below the build platform 200. A first printing material 11 and a second printing material 21 can be introduced into the printing container 30 depending on which printing material is to be used to print a layer of the three-dimensional printed object.

[0068] The printing reservoir 30 is designed to be capable of holding both the first printing material 11 and the second printing material 21. These materials can be introduced into the reservoir alternately based on the specific requirements of each layer of the three-dimensional object 2 to be printed. This method allows for efficient switching between materials during the printing process, facilitating the creation of complex multi-material objects without the need to pause to manually change or mix materials. Such a setup can be particularly advantageous for producing layers with varying material properties in successive printing processes.

[0069] 3, a build platform 300 is vertically movable and positioned above a rotatable disk 302. The disk 302 can rotate in a clockwise direction and contains a first material 310, a second material tank 320, a third material tank 330, and a wash tank 340. Depending on the rotational position of the disk 300, different tanks can be utilized for printing.

[0070] The rotatable disk 302 supports the operational flexibility of the mechanism, allowing the build platform 300 to access different materials or perform cleaning operations simply by rotating the disk to the desired position. This means that during the printing process, the build platform can align with either the material tanks to deposit different materials as required by the design of the three-dimensional object being printed, or with the cleaning tanks to ensure that the printed object or the platform itself is free of residue before new material is applied. Such a configuration is suitable for manufacturing processes where products require the integration of multiple materials of different properties. Incorporating an additional cleaning tank within the same mechanism prevents cross-contamination between different material layers. In this embodiment, the tanks are located on the rotatable disk.

[0071] 4 illustrates a general method for printing a three-dimensional object 4. A build platform 400 contains the three-dimensional object 4, which is almost completely immersed in a printing material 401 inside a printing material tank 410. A printing layer is printed onto the object 4 near the bottom 412 of the printing material tank 410, where more than half of the object is covered with the printing material.

[0072] Object 4 is built upside down, with each new layer cured by a light source (not shown) at the bottom of the tank as build platform 400 gradually raises object 4 upward, exposing the newly solidified layer and submerging the next layer in material 401, e.g., liquid printing resin. Immersion in printing material makes it difficult to clean the object in a second printing step with a different material, as all material must be cleaned from the object to avoid cross-contamination.

[0073] FIG. 5 illustrates a printing method according to the present invention. A build platform 500 accommodates a three-dimensional object 5, which is slightly immersed in a printing material 501 inside a printing material tank 510. A printing layer is printed on the object 5 near the bottom 512 of the printing material tank 510. Here, only a small portion of the object is covered with the printing material, and there is enough printing material to print one layer. This reduces cleaning efforts because only the material necessary to print one layer comes into contact with the object. The filling level of the printing material in the material tank can be controlled by a control means to maintain a constant filling level. This can be achieved by estimating the tank refill amount based on the volume of the printing layer. The filling level of the printing material in the material tank can be controlled by a control means to be in the range of 0.5 mm to 4 mm, preferably in the range of 1 mm to 2 mm. The filling level of the printing material in the material tank can also be controlled by a control means to be the minimum amount necessary to print one layer. The control means may also comprise a non-contact fill level sensor, which may comprise an ultrasonic transducer and / or a laser. The control means may also comprise a weight sensor, for example utilising the mass of the material being printed.

[0074] This approach offers several advantages, notably reducing the cleaning effort required after printing is complete between layers. By limiting the immersion depth, fewer portions of the object encounter potentially viscous printing material, reducing residue and potentially reducing instances of defects caused by excess material adhering to the object. Furthermore, this method can improve the efficiency of material usage, as only the amount required for each layer comes into contact with the object, minimizing waste. Such methods are advantageous for manufacturing processes where minimizing cleaning effort after or during processing is desired. Such a mechanism not only supports a cleaner and more efficient printing process, but also contributes to sustainability by reducing material waste.

[0075] 6 illustrates another printing method according to the present invention. A build platform 600 accommodates a three-dimensional object 6, which is slightly immersed in a printing material 601 inside a printing material tank 610. A printing layer is printed onto the object 6 near the bottom 612 of the printing material tank 610. The printing material 601 is stored in a printing material reservoir 622, from which it is transferred to the material reservoir 610 by a material transfer device 620. An overflow dam 630 maintains a constant fill level in the reservoir 610, as excess material overflows the reservoir 622.

[0076] Here, only a small portion of the object is covered with the printing material. This reduces cleaning efforts because only as much material as necessary to print one layer comes into contact with the object. This is particularly beneficial because it ensures a steady supply of fresh material without overfilling the tank, thereby maintaining the quality of each printed layer. Minimal immersion of the object in the printing material, combined with an overflow dam and material reuse, significantly reduces cleaning efforts and improves process efficiency. Such a mechanism is considered advantageous in scenarios where material consistency is important. The controlled environment also reduces the risk of contamination and ensures that only the necessary amount of material comes into contact with the object, thereby maintaining high cleanliness and precision. This method not only optimizes material usage, but also contributes to a more sustainable and cost-effective manufacturing process.

[0077] 7 shows a shoe with cleats 700 printed with the method according to the present invention. The shoe upper 701 and the cleated sole 702 are printed with different materials.

[0078] Specific designs and material properties can be tailored to different sports or user preferences and can provide improved performance characteristics such as improved shock absorption, improved traction, or increased comfort.

[0079] FIG. 8 shows a shin guard 800 printed with the method of the present invention.

[0080] The inner layer 801 is printed with a different material than the outer layer 802. The inner layer 801, which directly contacts the wearer's skin, can be printed using a softer, more flexible material to ensure comfort and impact cushioning. This material is ideally lightweight and can conform to the contours of the user's leg, providing a snug fit that maximizes protection while maintaining comfort. Conversely, the outer layer 802 is designed to absorb and distribute the forces of impact during sports or other activities. To this end, a tougher, more rigid material is used to resist punctures and scratches, ensuring the shin guard remains effective over time under rigorous use conditions. This two-material printing technique illustrates the method's ability to manufacture complex, multifunctional sports braces in a single, streamlined process. By integrating different material properties within the same article, the shin guard is optimized for both protection and comfort without the need for additional assembly steps.

[0081] A shoe 900 printed with the method of the present invention is shown in Figure 9. The shoe upper 901 and sole 902 are printed with different materials.

[0082] The shoe upper 901, which the foot rests on, can be printed from a material that provides flexibility, breathability, and comfort. This can be a flexible material that molds to the shape of the wearer's leg, providing a comfortable fit while allowing air circulation to keep the foot cool and dry. In contrast, the sole 902 is printed from a more durable and robust material that can withstand the wear and stresses of walking or running. This material must provide sufficient traction and support, potentially incorporating different densities and textures to optimize grip and cushioning, improving the shoe's performance and longevity. This method of using different materials in different parts of the shoe demonstrates the advanced capabilities of the 3D printing process, which allows for extensive product customization and optimization. By precisely controlling material properties, the shoe can be tailored to specific activities or user preferences, providing excellent fit, targeted support, and optimal comfort. One of the materials may have a Shore A hardness in the range of 70-80, a breaking elongation in the range of 240%-360%, and / or a tear strength in the range of 20-30 kN / m. The other material may have a Shore D hardness in the range of 68 to 74, a tensile modulus in the range of 1000 MPa to 1200 MPa, and / or an elongation at break greater than 50%.

[0083] 10 shows a sole 1000 printed with a method according to the present invention, which consists of different materials: a first sole material 1001, a second sole material 1002, and a third sole material 1003.

[0084] The first sole material 1001 may be designed to provide cushioning and shock absorption, ideal for areas of the sole that are subject to impact during activities such as walking and running. This material may be a flexible, resilient polymer that compresses under pressure but quickly returns to its original shape. The second sole material 1002 may be used for its durability and abrasion resistance, suitable for the outer periphery of the sole, which frequently comes into contact with the ground. It may be a tougher, more abrasion-resistant material that will withstand long-term use without degradation. The third sole material 1003 may be selected for its grip and traction, particularly for areas of the sole that require anti-skid properties to ensure safety and performance on a variety of surfaces. This use of different materials within a single sole exemplifies the versatility and precision of advanced 3D printing technology. It allows each section of the sole to be tailored according to its unique functional requirements, optimizing the overall performance of the footwear. By dividing the sole into multiple zones with tailored material properties, the product can provide improved comfort, longevity, and safety, all of which are important in high performance footwear.

[0085] 11 shows a shoe 1100 printed with a method according to the present invention. The shoe upper 1101 and sole 1102 are printed with different materials. The shoe upper 1101 and sole 1103 are not only horizontally connected but also vertically engaged with each other.

[0086] This vertical engagement requires some form of interlocking design, in which the sole elements and upper interlock or fit together like puzzle pieces, enhancing the strength and durability of the connection. This can be achieved through complementary ridges and grooves, snaps, or other mechanical fasteners printed directly into the material. This type of connection ensures that the upper and sole are structurally integrated, not just glued together, which can greatly improve the overall stability and durability of the shoe. Such a design improves the integrity and performance of the shoe by ensuring that the two components can effectively distribute and withstand the stresses and strains experienced during wear. An integrated structure can better absorb impact, provide improved support, and reduce the likelihood of separation or wear at the joints, which are often weak points in traditionally manufactured footwear.

[0087] 12 illustrates a method for printing a three-dimensional object 12 by providing a first printing material 1211 and a second printing material 1221 separated into a first material tank 1210 and a second material tank 1220, providing a build platform 1200, and a first printing step in which the object 12 is printed at least partially on the build platform 1200 using the first printing material 1211. A cleaning step for cleaning the object 12 is shown in which, after partially printing the object 12 on the build platform 1200, the build platform 1200 moves with the object 12 to the right toward the second material tank 1220. Along the way, it passes a cleaning fluid tank 1240, which is equipped with a first standing cleaning wave 1244 of cleaning fluid and an air knife 1242. In this embodiment, at least one cleaning tank is disposed between the printing material tanks.

[0088] The standing cleaning wave 1244 serves to effectively remove any remaining first print material or debris from the object 12, ensuring a clean surface for the next layer of material application. An air knife 1242 is positioned to dry the object by blowing away any remaining cleaning fluid, preparing it for further processing. This method incorporates cleaning directly into the print line, improving the quality of printed objects by ensuring a clean layer of material free of contamination from previous steps. Such a mechanism can be extremely beneficial in high-precision manufacturing environments where material purity and layer adhesion are critical.

[0089] 13 illustrates subsequent steps in printing the three-dimensional object 12 of FIG. 12 , shown after a cleaning step in which the object 12 is cleaned, and after a second printing step in which the object 12 is printed at least partially on the build platform 1200 using a second printing material 1221 from a second material tank 1220, the build platform 1200 is moved to the left together with the object 12. The build platform 1200 together with the object 12 passes through a cleaning fluid tank 1240, which includes a second standing cleaning wave 1246 of cleaning fluid and an air knife 1242.

[0090] As the build platform 1200 moves, it again passes through the cleaning fluid tank 1240. This time, the object 12 is subjected to a second standing cleaning wave 1246 of cleaning fluid designed to remove excess or particles from the second print material, ensuring the object's surface remains clean and prepared for any further processing steps. The air knife 1242 is once again used to quickly dry the object and remove any residual cleaning fluid or particles, similar to the first cleaning step in FIG. 12. This sequential, systematic cleaning and drying process incorporated into the material printing workflow improves the consistency and reliability of the printing process.

[0091] 14 illustrates a method of printing a three-dimensional object 14 by providing a first printing material 1411 and a second printing material 1421 separated into a first material tank 1410 and a second material tank 1420, providing a build platform 1400, and a first printing step of printing the object 14 at least partially on the build platform 1400 using the first printing material 1411. A cleaning step for cleaning the object 14 is shown in which, after partially printing the object 14 on the build platform 1400, the build platform 1400 moves with the object 14 to the right toward the second material tank 1420. Along the way, it passes through an ultrasonic cleaning tank 1440, which is equipped with an air knife 1442. The platform 1400 is moved vertically into the ultrasonic cleaning tank 1440, thereby immersing the object 14 in a cleaning solution inside the ultrasonic cleaning tank. After the ultrasonic cleaning step, the platform 1400 is moved upward, causing the object 14 to exit the ultrasonic cleaning tank 1440. The platform 1400 is then moved to the right toward the second printing material tank 1420. On the way there, it passes through an air knife 1442.

[0092] The build platform 1400, carrying the partially printed object 14, moves to the right toward the second material tank 1420 for further printing. During this transition, the platform passes through an ultrasonic cleaning tank 1440 equipped with an air knife 1442. The platform 1400 lowers the object 14 into the ultrasonic cleaning tank and immerses it in a cleaning solution. Ultrasonic cleaning uses high-frequency sound waves to violently vibrate the fluid, generating microcavitation bubbles. These bubbles effectively remove debris, residual print material, or contaminants from the object's surface, providing a thorough cleaning that is highly effective for delicate designs and complex shapes. After the ultrasonic cleaning process is complete, the build platform 1400 is lifted, lifting the object 14 out of the cleaning solution. As the platform continues its movement toward the second material tank, it passes beneath the air knife 1442. The air knife directs a high-velocity airflow at the object, effectively drying it by removing any remaining moisture or cleaning solution residue. This step is crucial because it prepares the object's surface for the application of the second printing material, ensuring that subsequent layers adhere properly. In this embodiment, the build platform is movable both vertically and horizontally. This vertically and horizontally movable platform feature can also be achieved with a Stewart platform. [Explanation of symbols]

[0093] 1, 2, 4, 5, 6, 12, 14 3D objects 100, 200, 300, 400, 500, 600, 1200, 1400 Build Platforms 10, 310, 1210, 1410 First material tank 11, 1211, 1411 First printing material 20, 320, 1220, 1420 Second material tank 21, 1221, 1421 Second Print Material 30 Printing container 302 Rotatable Disk 330 Third Material Tank 340, 1240 cleaning tank 401, 501, 601 Printing Materials 410, 510, 610 Print Material Tanks 412, 512, 612 bottom 620 Transfer device 622 Material tank 630 Overflow Dam 700 Non-slip shoes 701 Shoe Upper 702 Non-slip soles 800 shin guards 801 Inner layer 802 outer layer 900 shoes 901 Shoe Upper 902 Sole 1000 soles 1001 First shoe sole material 1002 Second shoe sole material 1003 Third shoe sole material 1100 shoes 1101 Shoe upper 1102 Shoe sole 1242, 1442 Air Knife 1244 First Cleansing Wave 1246 Second Cleansing Wave 1440 Ultrasonic Cleaning Tank

Claims

1. 1. A method of printing a three-dimensional object, comprising: providing at least first and second printing materials separated into at least a first material tank and a second material tank; providing a build platform; a first printing step of printing the object at least partially on the build platform using the first printing material; a cleaning step of cleaning the object from the first and / or second printing materials; a second printing step of printing the object at least partially on the build platform using the second printing material; The method includes at least

2. The washing step providing one or more cleaning tanks containing cleaning fluid; providing one or more air knives; providing one or more standing waves of cleaning liquid; cleaning the object by exposing the object to the one or more standing waves of a cleaning liquid; drying the cleaned object by exposing it to the one or more air knives; The method of claim 1 , comprising at least

3. The washing step providing one or more cleaning tanks containing a cleaning solution, at least one of the cleaning tanks being a dedicated ultrasonic cleaning tank configured for ultrasonic cleaning; providing one or more air knives; cleaning the object by immersing the object in the ultrasonic cleaning tank; drying the cleaned object by exposing it to the one or more air knives; The method of claim 1 , comprising at least

4. The method of claim 2 , wherein at least one of the material tanks and / or at least one of the cleaning tanks is horizontally movable.

5. The method of claim 1 , wherein the tank is disposed on a rotatable disk.

6. 6. The method according to claim 2, wherein at least one washing tank is arranged between the printing material tanks.

7. The method of claim 1 , wherein the build platform is vertically and horizontally movable.

8. The method of claim 7 , wherein the build platform comprises a Stewart platform.

9. The method of claim 1 , wherein at least one of the print materials is a liquid photopolymer resin.

10. The method of claim 1 , wherein the printing utilizes digital light processing (DLP).

11. The method of claim 1 , wherein the printing is performed by photopolymerization.

12. The method of claim 11 , wherein the photopolymerization is achieved by UV light.

13. The method of claim 1 , wherein the first and second print materials have different mechanical properties.

14. The method of claim 13, wherein the first material has a Shore A hardness in the range of 70-80.

15. The method of claim 13 or 14, wherein the first material has an elongation at break in the range of 240% to 360%.

16. The method of claim 13 or 14, wherein the first material has a tear strength in the range of 20 to 30 kN / m.

17. The method of claim 13 or 14, wherein the second material has a Shore D hardness in the range of 68 to 74.

18. The method of claim 13 or 14, wherein the second material has a tensile modulus in the range of 1000 MPa to 1200 MPa.

19. 15. The method of claim 13 or 14, wherein the second material has an elongation at break greater than 50%.

20. 10. The method of claim 1, wherein the fill level of the printing material in the material tank is controlled by a control means to maintain a constant fill level.

21. 21. The method of claim 20, wherein the method includes estimating tank refills based on a volume of a printing layer.

22. The method according to claim 20 or 21, wherein the filling level of the printing material in the material tank is controlled by a control means to be in the range of 0.5 mm to 4 mm, preferably in the range of 1 mm to 2 mm.

23. 22. The method of claim 20 or 21, wherein the fill level of the printing material in the material tank is controlled by a control means to be the minimum amount required to print one layer.

24. 22. The method of claim 20 or 21, wherein the control means comprises an overflow dam.

25. 22. A method according to claim 20 or 21, wherein the control means comprises a non-contact fill level sensor, the sensor comprising an ultrasonic transducer and / or a laser.

26. 22. The method of claim 20 or 21, wherein the control means comprises a weight sensor.

27. 22. Sports equipment manufactured according to the method of any one of claims 1 to 5, 7 to 14, and 20 to 21.

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