Device and method for 3D printing with microwave thermal post-processing

Abstract

The invention concerns a method for printing three-dimensional products, for example food, pharmaceutical or cosmetic products. The method comprises a first step of depositing an amount of material on a base (1), in one or more stacked layers, according to a predetermined path; a second step of applying an established amount of near-field microwave radiation to a part or parts of the layer or layers without affecting the rest of the amount of deposited material. The method can be carried out in a 3D printing device. The device comprises a near-field microwave irradiation module (4) comprising a probe configured to apply near-field microwaves to predetermined parts of the 3D product that is to be manufactured. The irradiation module can be moved by a movement mechanism.

Description

[0001] DESCRIPTION

[0002] 3D printing device and method with microwave thermal post-processing.

[0003] OBJECT OF THE INVENTION

[0004] The invention belongs to the field of 3D printing, and relates to a method of 3D printing products such as food, pharmaceutical and cosmetic compositions with microwave thermal post-processing and to a device that uses said method.

[0005] BACKGROUND OF THE INVENTION

[0006] Three-dimensional (3D) printing technology, created in the 1980s, was developed to print materials such as plastic, metal, and cement. Among these technologies is additive manufacturing (extrusion), in which the material, after passing through an extruder head, is deposited layer by layer to form a three-dimensional object.

[0007] The application of 3D printing to food is a recent, experimental but promising field that allows for the manufacture of products that reduce or eliminate food handling, with special and customized compositions and shapes, increasing appeal, making them easier for people with digestive problems to eat, and contributing to the treatment of diseases, among other benefits.

[0008] While great precision has been achieved in food deposition, one of the main challenges in 3D food printing relates to stabilizing the food mixture once it's deposited outside the extruder head. This problem hampers the ability to guarantee a faithful and stable printed shape, as there's a permanent risk of collapse. By selectively applying energy to certain parts of the food, the structure can be stabilized, cooking it, and inducing chemical reactions that improve, for example, its flavor.

[0009] An existing solution involves applying a laser beam to the food. The laser light selectively heats a portion of the food, achieving the aforementioned objectives. However, the laser primarily heats the surface of the food, which can lead to overcooking or even burning in that area, while the interior of the food may remain raw. Furthermore, the thermal conductivity of the food can influence the rate at which it transmits heat to the interior. Another existing solution uses microwave radiation. The food is printed inside a shielding chamber that confines the microwave radiation within the chamber. Microwave radiation is applied either after extruding the food to the entire food or product or to a relatively large portion of it, or at the time of extrusion.These methods do not allow for the application of microwave energy in a differential and localized manner, adjusting the irradiated portion and the energy deposited based on the needs of structural stabilization and nutritional characteristics.

[0010] The above drawbacks can also arise when applying 3D printing to pharmaceutical and cosmetic compositions, and in general to any product that requires structural stabilization or heat treatment through the application of thermal energy in a localized and regulated manner.

[0011] DESCRIPTION OF THE INVENTION

[0012] The invention described herein seeks to address at least some of the above problems by providing a 3D printing method and device that employ the application of near-field microwave radiation by evanescent waves (shortened herein to “near-field microwave radiation”). This radiation fades over small distances, allowing the application of energy in precise, small, and local locations without affecting the rest of the printed product. Advantageously, thanks to the relatively small range of near-field microwave radiation, the food does not need to be in a shielding chamber, which makes the device lighter and allows for more flexible observation of the food while it is being printed and processed.

[0013] The 3D printing device with microwave thermal post-processing object of the invention is described below.

[0014] The device, which creates and processes a 3D food product using near-field microwave radiation, comprises:

[0015] - a base that supports the 3D product being created,

[0016] - an extruder module,

[0017] - a near-field microwave irradiation module,

[0018] - a displacement mechanism, and

[0019] - a controller. The base is preferably positioned horizontally and defines a reference plane. Two directions, X and Y, are defined, perpendicular to each other and contained within the reference plane. A Z axis is also defined, which is perpendicular to the reference plane. In one embodiment, the base is provided with a heater that heats it to a predetermined temperature to improve printing of the product, for example, by increasing adhesion to the base and facilitating detachment of the finished product.

[0020] In one embodiment, the extruder module includes a drive unit and a head located adjacent to each other and connected. In another embodiment, the extruder module includes only one head connected to a drive unit physically separated from the device by a tube.

[0021] The drive unit propels feed loaded into a reservoir in the feed unit toward the die, where a filament of feed is released, forming the 3D product. The drive unit propels the feed using any device familiar to the technical expert, such as a compressed air cylinder or an extruder screw.

[0022] In one embodiment, to achieve finer control of food extrusion and therefore printing, the head is provided inside with an extruder screw or a peristaltic pump that allows more precise regulation of the advance and retreat of the food during printing of the 3D product.

[0023] In one embodiment, the extruder module incorporates a cooling and heating device that cools and heats the food passing through it to form the 3D product at a predetermined temperature. Specifically, the cooling and heating device is capable of maintaining the food between 4°C and 70°C depending on the printing requirements. This improves the ease of printing and the quality of the 3D product because the extrusion temperature significantly affects the properties of the extruded food.

[0024] The extruder module and the base can be moved between them in a controlled manner to build the 3D product according to a sequence of method instructions.

[0025] The near-field microwave irradiation module comprises a near-field probe or antenna. The probe is connected to a microwave generator located outside the near-field microwave irradiation module via a cable. The probe applies localized near-field microwave radiation to a portion of the already printed 3D product according to a predetermined sequence of method instructions. In one embodiment, the probe is a coaxial applicator open at one end to the exterior through which the probe radiates the near-field microwaves.

[0026] In one embodiment, the coaxial applicator, comprising a center conductor, can extend or retract the center conductor, thereby modifying the resolution of the near-field microwave radiation. In another embodiment, the center conductor is fixed to the coaxial applicator.

[0027] In one embodiment, the device further comprises a common carriage on which the extruder module and the irradiation module are mounted, such that when the common carriage moves, the two modules move simultaneously. In another embodiment, the device comprises an extruder carriage on which the extruder module is mounted and an irradiator carriage on which the near-field microwave irradiation module is mounted, such that the movements of the modules are independent.

[0028] In one embodiment, the movement mechanism comprises rails that allow the movement of the carriage or carriages on the X and Y axes and the movement of the base on the Z axis. In another embodiment, the movement mechanism allows the movement of the carriage or carriages on the X and Z axes and the movement of the base on the Y axis. The modules can move along the same X-axis rail or each module can move along an individual X-axis rail.

[0029] Movement can be achieved by any method known in the field of 3D printing, such as belts pushing carriages or motorized carriages with smooth or toothed wheels.

[0030] The controller generates a sequence of commands for the modules, the base if heated, the extruder screw or the peristaltic pump of the head and the motorized movement mechanism so that the device builds the 3D product.

[0031] The 3D printing method with microwave thermal post-processing is described below, which comprises the following sequence of steps:

[0032] - a first step of depositing a quantity of food on the base, in one or several superimposed layers, according to a predetermined trajectory and, - then, taking into account the needs of structural stability, nutrition, hygiene, etc., a second step of applying a set quantity of microwave radiation in the near field to one or some parts of the layer(s) without affecting the rest of the deposited food.

[0033] The deposition of food (or material in general) and near-field microwave irradiation are determined by a sequence of instructions generated from a 3D model of the product to be manufactured. The instructions are loaded into the controller, which converts them into commands for module movement, base heating, and activation and deactivation of the near-field microwave irradiation module, in addition to any other controllable elements.

[0034] This allows for precise, adjustable, and rapid heat treatment, depositing energy not only on the surface but also inside the food. This allows for the construction of a desired shape with sufficient stability, adapting to different types of food, and simultaneously treating a large volume of food.

[0035] The product can be created in a single deposition or in superimposed layers that have been precalculated using methods known in the field of 3D printing.

[0036] For more complex or voluminous products, the first and second steps above are repeated successively in the same order to sequentially create a 3D product in layers. Thanks to the adjustable application of near-field microwave radiation to the necessary parts, rapid, precise, high-resolution, and gradual consolidation of the product is achieved as it is printed. The selective application of microwave radiation to different parts of each layer, depending on the composition of the food and the structural needs of the product, allows for the generation of products with highly complex geometry, materials, and structural, nutritional, and organoleptic properties.

[0037] The above description sets forth the method and device for application in 3D food printing. In this case, the following effects can be achieved: pasteurization, drying, cooking, fat melting, hot gelation, protein denaturation, phase transitions, improved nutrient bioaccessibility, and chemical reactions such as the Maillard reaction. However, the scope of the invention is not limited to foods and can also be applied to substances that require heat treatment with the aforementioned requirements after their deposition, such as pharmaceutical and cosmetic compositions and industrial applications that will be clearly determined by those skilled in the art. DESCRIPTION OF THE DRAWINGS

[0038] To complement the description being made and in order to help better understand the characteristics of the invention, in accordance with a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description, in which the following has been represented for illustrative and non-limiting purposes:

[0039] Figure 1.- Shows a front view of a preferred embodiment of the device of the invention.

[0040] Figure 2.- Shows a front view of the extruder module of the preferred embodiment of the device while printing a 3D product.

[0041] Figure 3.- Shows a perspective view of the near-field microwave irradiation module of the preferred embodiment of the device.

[0042] Figure 4.- Shows a cross-section of the near-field microwave irradiation module of the preferred embodiment of the device.

[0043] PREFERRED EMBODIMENT OF THE INVENTION

[0044] A preferred embodiment of the 3D printing method with microwave thermal post-processing and a device capable of implementing the method are described below.

[0045] Referring to Figures 1 to 4, the 3D printing device with microwave thermal post-processing comprises:

[0046] - a base (1) that supports a 3D product (100) being manufactured,

[0047] - a base car,

[0048] - an extruder module (2),

[0049] - an extruder carriage (3),

[0050] - a near-field microwave irradiation module (4),

[0051] - an irradiator cart (5),

[0052] - a displacement mechanism, and

[0053] - a controller. The base (1) is located horizontally and defines a reference plane. Two directions X and Y are defined, perpendicular to each other and contained in the reference plane. A Z axis is also defined, which is perpendicular to the reference plane.

[0054] The extruder module (2) comprises a head. In addition, a drive unit (30) is provided located outside the extruder module (2). The head comprises a nozzle (20) arranged at an outlet end. The extruder module (2) also incorporates a cooling and heating device that cools and heats the food that passes through it to form the 3D product (100) at a predetermined temperature. Specifically, the cooling and heating device is a Peltier cell capable of maintaining the food between 4 ° C and 70 ° C according to the printing requirements. In this way, the ease of printing of the 3D product (100) is improved.

[0055] The drive unit (30) comprises a motorized piston and a cylinder connected to the extruder module (2) by a flexible tube. The movement of the motorized piston is carried out by means of compressed air. The motorized piston propels a feed previously loaded in the cylinder towards the head, through whose nozzle (20) a filament of feed exits which forms the 3D product (100). The extruder module (2) and the base (1) are movable relative to each other in a controlled manner to build the 3D product (100) according to a sequence of instructions of the method.

[0056] The near-field microwave irradiation module (4) comprises a probe or antenna with a connector coupled to the probe. The probe is connected to a microwave generator located outside the near-field microwave irradiation module (4) by a cable coupled to the connector. The probe applies localized near-field microwave radiation to a portion of the 3D product (100) according to a predetermined sequence of method instructions.

[0057] As can be seen in Figure 4, the probe is a coaxial applicator that is open to the outside at one end (6) through which the probe radiates the microwaves in the near field. The coaxial applicator comprises a central conductor (10) whose position is fixed in the module.

[0058] The extruder module (2) is mounted on the extruder carriage (3) and the near-field microwave irradiation module (4) is mounted on the irradiator carriage (5), so that the movements of the modules (2, 4) are independent. The base (1) is mounted on the base carriage. The carriages are motorized by means of stepper motors.

[0059] The movement mechanism comprises rails to which the extruder carriages (3) and irradiator (5) and the base carriage are coupled. Specifically, the extruder carriages (3) and irradiator (5) move along rails arranged along the X and Z axes, referenced by the numbers 8 and 9 respectively. The base carriage moves along rails arranged on the Y axis. The extruder carriage (3) and the irradiator carriage (5) move along the same X-axis rail (8). In turn, the X-axis rail (8) is mounted on two parallel Z-axis rails (9) located on both sides of the base (1) and along which the X-axis rail (8) moves.

[0060] The controller generates, from a 3D model of the 3D product (100) to be manufactured, a sequence of orders that it communicates to the modules (2, 4) (extrusion and irradiation), to the carriage motors (3, 5) (movements), to the cooling and heating device (temperature) and to the base (1) (heating and movement) so that the device builds the 3D product (100) faithful to the 3D model.

[0061] The 3D printing method with microwave thermal post-processing to build a 3D product (100) previously modeled by layers from the 3D model comprises the following sequence of steps:

[0062] 1.- Deposit a quantity of food in a layer according to a predetermined sequence of movements.

[0063] 2.- Apply a predetermined amount of near-field microwave radiation energy to predetermined parts of the layer.

[0064] 3.- Repeat the sequence of steps 1 and 2 until all layers of the 3D product (100) have been deposited and treated with microwaves.

[0065] The first layer is deposited on the base (1). The successive layers are deposited superimposed on top of the previous one.

[0066] The extruder module (2), coordinated with the drive unit (30), deposits the amount of feed from step 1. Once this step is completed, the extruder module (2) moves away from the deposited layer, and the near-field microwave irradiation module (4) is activated, irradiating predetermined parts (or the entire layer, as the case may be) of the layer by moving towards them, achieving great precision in the location and the deposited energy. To simplify the determination of the sequence of movements of the near-field microwave irradiation module (4), it repeats the same sequence as the extruder module (2). Once the irradiation is completed, the near-field microwave irradiation module (4) is removed and the extruder module (2) is activated, repeating the sequence of steps to print and process the next layer.

Claims

CLAIMS A 3D printing device with microwave thermal post-processing that is capable of manufacturing a 3D product (100), and comprises: - a base (1) configured to support the 3D product (100) intended to be manufactured, - an extruder module (2) configured to extrude a predetermined quantity of material intended to form the 3D product (100), - a movement mechanism configured to move the base (1) and the extruder module (2) according to a predetermined sequence of movements, - a controller configured to generate a predetermined sequence of commands for the modules (2, 4) and the movement mechanism from a 3D model of the 3D product (100), characterized in that the device further comprises a near-field microwave irradiation module (4) comprising a probe configured to apply near-field microwaves to predetermined parts of the 3D product (100) intended to be manufactured, and is movable by the movement mechanism. The 3D printing device of claim 1, wherein the probe is a coaxial applicator open to the outside at one end (6) thereof and through which the probe is configured to radiate near-field microwaves. The 3D printing device of claim 2, wherein the coaxial applicator comprises a central conductor (10) configured to extend and retract, modifying the resolution of the near-field microwave radiation.The 3D printing device of claim 1, wherein. - the movement mechanism comprises X-axis rails (8), Y-axis rails and Z-axis rails (9) each defining movement directions X, Y and Z, - the 3D printing device additionally comprises motorized carriages (3, 5) to which the modules (2, 4) are coupled and another motorized carriage to which the base (1) is coupled, and are mounted with the ability to move on the X-axis rails (8) and the Z-axis rails (9), on the one hand, and the Y-axis rails, on the other, respectively, according to the X, Y and Z directions. The 3D printing device of claim 1, wherein - the extruder module (2) comprises a head configured to output material that forms the 3D product (100) and, - the head comprises an extruder screw or a peristaltic pump intended to control the flow of material that forms the 3D product (100) according to the predetermined sequence of orders generated by the controller. The 3D printing device of claim 1, wherein the extruder module (2) comprises a cooling and heating device configured to cool and heat the material that passes through the extruder module (2) to form the 3D product (100) to a predetermined temperature controlled by the controller. A 3D printing method with microwave thermal post-processing implemented by a device of any one of claims 1-6, characterized in that it comprises the following sequence of steps: - a first step of depositing a quantity of material on the base (1), in one or several superimposed layers, according to a predetermined trajectory, - a second step of applying a set amount of near-field microwave radiation to one or more portions of the layer(s) without affecting the remainder of the deposited material. The 3D printing method of claim 7, wherein the sequence of the first and second steps are repeated to create a 3D product (100) by layers.

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