3D printing apparatus, 3D printing method and 3D tubular object obtained by said method

Abstract

3D printing equipment and 3D printing method. The equipment (1) includes: - a build platform having an outer surface; - means for providing a polymerizable fluid resin (4) on the surface; - a radiation source (5) for emitting a radiation beam (7) toward the surface; - a beam positioning device (8) for variably positioning the impact point of the beam (7); and - means for controlling the source (5) and the positioning device (8) to manufacture a 3D tubular object (100) according to a model; wherein the build platform includes a rod (3) forming a tubular surface (2) about a longitudinal axis (9) such that the outer surface of the build platform is contained in the tubular surface (2); and the positioning device (8) is configured to variably position the impact point of the beam (7) at different points of the fluid resin (4) provided on the tubular surface (2).

Description

Technical Field

[0001] This invention relates to the field of manufacturing objects using additive manufacturing processes commonly known as 3D printing.

[0002] More specifically, the present invention relates to a 3D printing apparatus for manufacturing at least one tubular 3D object based on a printed model. The 3D printing apparatus includes:

[0003] - A construction platform with an outer surface;

[0004] - An apparatus for providing resin, configured to provide a fluid resin that can be polymerized by electromagnetic radiation on the outer surface of the construction platform;

[0005] - An electromagnetic radiation source configured to emit an electromagnetic radiation beam suitable for polymerizing the fluid resin from a source output toward the outer surface of the construction platform;

[0006] - A beam positioning device configured to variably position the impact point of the beam on the fluid resin provided on the outer surface; and

[0007] - A control device configured to control the beam positioning device and the electromagnetic radiation source according to the printed model to manufacture the 3D tubular object.

[0008] The present invention also relates to a corresponding 3D printing method, and a tubular 3D object obtained by said method. Background Technology

[0009] In the field of 3D printing, solutions that allow the fabrication of objects with high resolution are known. In particular, stereolithography (SL) is known to allow the printing of 3D objects at high resolution because such techniques are based on the continuous creation of micrometer layers of resin (typically 10 micrometers or more thick) polymerized by incident electromagnetic radiation beams, usually ultraviolet light. The incident light typically comes from a laser or a uniform light source masked according to the points to be polymerized in each layer of resin. In both cases, high precision can be achieved at the points to be polymerized, thus enabling the technology to print 3D objects with high resolution. Stereolithography requires the use of a tray filled with resin to be polymerized, where successive horizontal layers of material are created from a flat substrate used as a build platform. During the creation of each layer, the equipment remains stationary, and the build platform does not move. Typically, after each layer is created, the 3D object in the construction must be moved and / or new resin must be added to create the next layer. This layer-by-layer manufacturing makes the printing method slow. Generally, the time required to create a 3D object increases with resolution; that is, the smaller the detail to be created, the finer the successive layers must be, and therefore the more layers are needed. Furthermore, stereolithography involves high resin expenditure because, on the one hand, the object to be printed is immersed in the printing tray and needs to be covered with sufficient resin; on the other hand, it is necessary to create support structures for the cantilevered parts of the object, which must then be removed to achieve the complete object.

[0010] Other types of techniques offer higher manufacturing speeds and material economy, although they do not achieve the same precision as stereolithography. This is the case for FDM (Fused Deposition Modeling), a technique based on point-to-point deposition of molten thermoplastic material. In known FDM techniques, it is impossible to obtain high-resolution details below 200 micrometers. The main reason is that the nozzle delivering the molten material cannot be too small, as the material will not flow through it. Another drawback of FDM is the roughness of the manufactured objects due to point-to-point deposition. Furthermore, the rate at which the molten material flows out of the nozzle is often difficult to control with high precision. Therefore, FDM technology is not suitable for producing high-resolution objects with very small dimensional details.

[0011] A specific application of 3D printing is the creation of tubular objects. In this document, the term "tubular object" generally refers to any object having an empty interior region defined by a tubular surface and a polymeric material extending over all or part of said tubular surface. Unless otherwise stated, the term "tubular surface" generally refers to a surface extending about a longitudinal axis and is not necessarily limited to a regular shape, such as a cylinder.

[0012] FDM technology can be used for 3D printing tubular objects. However, a drawback of these technologies is that the tubular surface of the empty areas of the printed tubular objects often exhibits significant irregularities between the points where molten material is deposited by the nozzle. To address this issue, a specific FDM 3D printing method has been proposed (GUERRA SÁNCHEZ, Antonio. Contribution to bioabsorbable stent manufacture with additive manufacturing technologies (Doctoral dissertation at Universitat de Girona, 2019; available at: http: / / hdl.handle.net / 10803 / 667867)). In this specific method, material is deposited through a nozzle onto the surface of a cylindrical core. Because the molten material is deposited through the nozzle onto the smooth cylindrical surface of the core, a more regular tubular surface can be obtained for the empty areas of the printed tubular object. However, in addition to the inherent drawbacks of FDM technology discussed above, a problem with this particular method is that the combination of point-to-point deposition and the relative rotation between the nozzle and the cylindrical core limits the printing speed.

[0013] JP2000043150A discloses a 3D printer designed to manufacture composite products comprising a metal shaft and gears. Only the gears are made from polymeric resin via 3D printing. The shaft is rotatably mounted within a liquid resin tank, and a radiant beam causes the resin on the shaft to polymerize to form the gear. The final product is a composite where the gear, formed by 3D printing, is integral with the metal shaft.

[0014] US2019311822A1 discloses a similar method in which the composite product is an electrically conductive rod with a concentrator. The rod is partially immersed in a liquid resin tank and rotated at a controlled speed to adjust the thickness of the resin layer formed on the rod. A radiant beam polymerizes the resin layer on the rod to form the concentrator. The final product is a composite where the concentrator, formed by 3D printing, is integral with the rod.

[0015] Therefore, a 3D printing solution is needed to print high-resolution tubular objects and address the aforementioned issues of slowness, cost, and additional steps. Summary of the Invention

[0016] The purpose of this invention is to provide a 3D printing device of the type described at the beginning of this document, which can avoid the problems already identified above.

[0017] This objective is achieved by a 3D printing device of the type described at the beginning of this document, characterized in that the build platform includes a rod having a longitudinal axis, the rod forming a tubular surface around the longitudinal axis such that the outer surface of the build platform is included in the tubular surface, and wherein the beam positioning device is configured to variably position the impact point of the beam at different points on at least a portion of the fluid resin provided on the tubular surface.

[0018] The tubular surface is formed in at least a portion of the rod, but not necessarily along the entire rod. The rod itself is not necessarily formed as a single piece.

[0019] In this way, instead of using a planar support structure as in traditional stereolithography, a rod with a tubular surface is used as a building platform: resin is provided to cover the tubular surface of the rod and polymerized directly thereon. The thickness of the fluid resin on the support corresponds to the thickness of the polymerized resin layer, eliminating possible shrinkage or expansion effects during polymerization. Therefore, continuous layers are created concentrically around the rod. In this manner, the number of layers is significantly reduced compared to the fabrication of horizontal layers arranged on top of each other. In some cases, a single layer may be sufficient to create a 3D tubular object.

[0020] This reduction in the number of layers and their arrangement offers several advantages. First, manufacturing time is significantly reduced. Furthermore, the resulting object exhibits increased strength due to fewer layer connections and the concentric arrangement of their layers. On the other hand, it is easier to fabricate objects with cantilevered portions compared to stereolithography methods known in the art, as the aforementioned support structures, which must subsequently be removed, are unnecessary. Additionally, therapeutic agents can be encapsulated between the layers due to their concentric arrangement. Finally, 3D tubular objects with concentric layers made of different resins can be fabricated, which is particularly advantageous when creating tubular objects, for example, where different mechanical properties are required between the inner and outer layers. All of these contribute to the fact that the solution proposed herein is particularly advantageous for fabricating 3D tubular objects requiring tubular empty regions.

[0021] Preferably, the beam positioning device is configured to variably position the impact point of the beam on the fluid resin by at least the following means:

[0022] - Circumferential positioning around the longitudinal axis in the circumferential direction; and

[0023] - Longitudinal positioning along the longitudinal direction defined by the longitudinal axis.

[0024] Therefore, a 3D printing model can be used where each layer's points are defined using only two coordinates: one corresponding to the relative circumferential position between the beam and the rod, and the other corresponding to the relative longitudinal position. This type of coordinate differs from the Cartesian coordinates used in conventional stereolithography. In the case of this invention, it is not necessary to create layers in the XY plane and deposit each layer along the Z-axis. Instead, in this invention, each layer already produces a three-dimensional volume, formed according to a tubular geometry, although defined by only two coordinates. This type of positioning simplifies 3D modeling and reduces the computational cost required for printing equipment because it eliminates the need to decompose Cartesian coordinates into relative positions between the support and the equivalent beam. In particular, the described type of positioning involves cylindrical coordinates and is especially advantageous when the support to be printed is tubular, and particularly advantageous if it is cylindrical.

[0025] Preferably, the beam positioning device is further configured to variably position the impact point of the beam on the fluid resin by means of the distance positioning between the source output and the tubular surface of the rod, thereby defining the beam length. This distance positioning has two main advantages: first, it can determine a suitable beam length so that the focal point coincides with the incident point on the resin. Second, it allows the beam length to adapt to the geometry of the rod, so the rod does not have to be cylindrical, and therefore other less regular shapes can be envisioned.

[0026] Preferably, the electromagnetic radiation includes at least one from the list of: infrared radiation, visible light, and ultraviolet radiation. Ultraviolet radiation, UV, is widely used in stereolithography; however, the apparatus of the present invention is not limited to specific UV-polymerizable resins. Different fluid resins can also be envisioned for specific applications, for example, biocompatible resins having photoinitiators sensitive to visible or infrared wavelengths (IR).

[0027] Preferably, the tubular surface of the rod has rotational symmetry about the longitudinal axis. When the rod is a body of revolution, the distance from the longitudinal axis to the tubular surface of the rod is the same for every longitudinal point at any angle. This facilitates beam positioning and reduces the computational cost required to determine this positioning based on the printed model.

[0028] The tubular surface of the rod is preferably conical, truncated conical, or cylindrical, thereby enhancing the aforementioned advantages, particularly in the case of a cylindrical shape. In fact, in the case of a cylindrical shape, the distance between the longitudinal axis and the tubular surface of the rod is the same for any angle and along the entire length of the tubular surface of the rod.

[0029] In this art, the term diffuse surface refers to a surface in which incident electromagnetic radiation is reflected at multiple angles rather than a single reflection angle. This phenomenon typically occurs due to irregularities on the surface, the magnitude of which is comparable to the wavelength of the incident electromagnetic radiation. Conversely, specular surfaces are those where specular reflection is more pronounced, occurring when the reflectivity is close to zero at all but one angle. These are typically smooth, polished materials. Therefore, diffuse surfaces essentially have no specular reflection.

[0030] Preferably, the tubular surface of the rod is a diffuse surface for the wavelength of the electromagnetic radiation. Therefore, the reflected electromagnetic radiation energy is distributed at different angles, rather than being concentrated in one direction as in specular reflection, which could otherwise lead to polymerization of the fluid resin in the path of specular reflection. Consequently, the precision of the manufactured object is increased because less parasitic polymerization occurs at adjacent points affected by the reflected beam.

[0031] Preferably, the tubular surface of the rod does not reflect the electromagnetic radiation, i.e., the incident beam is substantially not reflected by the tubular surface, and energy is absorbed there, at least for the wavelength corresponding to the electromagnetic radiation, thereby minimizing the effects of the parasitic polymerization described above.

[0032] Preferably, the tubular surface of the rod is opaque to the electromagnetic radiation, such that the incident beam does not penetrate through the rod and / or is unaffected by other internal reflections, which could lead to undesirable polymerization if there is fluid resin at the exit point.

[0033] Preferably, the rod comprises a hard core encased in an outer layer made of an elastomeric material, the outer layer forming the tubular surface of the rod. The hard core provides high mechanical resistance to the rod and makes it difficult to twist. Furthermore, the elastomeric layer facilitates removal of the object after printing due to its elasticity. Additionally, the elastomeric layer has a diffuse surface for electromagnetic radiation from the beam. The hard core is preferably made of metal, particularly steel, to maximize the above effects while maintaining a reasonable manufacturing cost for the device. The elastomeric material is preferably latex or nylon, whose physicochemical properties are particularly favorable for achieving the aforementioned release and diffuse reflection effects.

[0034] Preferably, the resin supply device includes a resin tank arranged such that a rod passes through the resin tank, allowing fluid resin to be supplied directly from the resin tank to the tubular surface of the rod. This arrangement simplifies the equipment because it avoids the need for more complex devices to supply resin to the tubular surface of the rod, such as by pouring, brushing, or using transfer rollers. This minimizes the cost of manufacturing the equipment and simplifies the control methods necessary to manage the fluid resin supply. If necessary, the resin tank can be filled with more liquid resin as it polymerizes.

[0035] In a preferred embodiment, the rod is arranged horizontally such that all tubular surfaces are below the resin loading height in the resin tank. Therefore, the longitudinal axis is horizontal, and thus it is longitudinal. Preferably, the device includes means for rotating the rod about its longitudinal axis, such that, in order to print a dot at a given longitudinal position, the beam strikes the highest point in the tubular surface of the rod for that given longitudinal position. Therefore, the thickness of the resin to be polymerized for that point corresponds to the distance between the height of the dot and the resin loading height. Thus, taking into account the shape of the rod and the possible shrinkage or expansion of the fluid resin during polymerization, the thickness of each layer can be controlled by the resin loading height. Preferably, when the fluid resin is used up during printing, the tank is refilled with additional fluid resin. Those skilled in the art will understand that the loading height can be varied; for example, it may be necessary to increase the level between consecutive printed layers, or alternatively, it may be necessary to lower the rod. This embodiment is particularly advantageous if the rod is cylindrical, because the distance between the loading height and the highest point of the rod is the same along the entire length of the rod, making it easier to control the thickness of the resin layers.

[0036] In an alternative embodiment, the rod is arranged horizontally such that a portion of its tubular surface lies above the resin loading height in the resin tank, while another portion lies below it. Therefore, as the rod rotates about its longitudinal axis, the fluid resin is dragged by the tubular surface of the rod from the bottom of the tank to the top of the loading height, where it can be irradiated and polymerized. This allows for the production of a thin layer that can be precisely polymerized. Experts will understand that the layer thickness will depend on the properties of the fluid resin, particularly its viscosity, and the tubular surface of the rod, particularly its porosity or protrusions. Therefore, the desired layer thickness can be obtained by controlling these properties.

[0037] In another preferred embodiment, the resin tank comprises a container arranged around the rod, such that a resin chamber is defined between the container and the tubular surface of the rod, the container being made of a material transparent to electromagnetic radiation. In this way, fluid resin can be irradiated from the outside of the container through the transparent wall toward the resin chamber. This has several advantages. First, the thickness of the resin layer is determined very precisely by the thickness of the resin chamber. Furthermore, since the rod is enclosed by the container, it can be arranged at the most convenient angle, even vertically. Another advantage is minimized resin waste, as only a precise amount of fluid resin needs to be supplied to the resin chamber.

[0038] Preferably, the 3D printing equipment further includes a temperature control device configured to control the temperature of the fluid resin supplied by the resin supply device onto the tubular surface of the rod, thereby allowing control of the viscosity of the fluid resin. Preferably, the temperature control device includes a thermoelectric cell, also known as a Peltier cell, and is therefore capable of heating and cooling the temperature of the fluid resin.

[0039] In a preferred embodiment, the electromagnetic radiation source includes an electromagnetic radiation generator and an optical fiber guiding module for guiding the electromagnetic radiation to an optical fiber output, such that the source output is the optical fiber output. Preferably, the optical fiber output includes one or more lenses to concentrate the output radiation into a narrow beam.

[0040] In an alternative embodiment, the electromagnetic radiation source includes a laser with a laser output, such that the source output is the laser output, thereby utilizing the narrow and focused characteristics of the laser beam to influence the desired point with high precision. Those skilled in the art will understand that the guidance of the laser beam can include known elements, as well as other non-limiting examples, mirrors, prisms, lenses, or combinations thereof. In the context of this invention, the laser output refers to the point where the beam leaves the guiding system (if present) and is guided to the point of impact on the tubular surface of the rod.

[0041] Preferably, the rod is rotatably mounted about a longitudinal axis, and wherein the beam positioning device comprises:

[0042] A rotation control element is used to control the circumferential positioning of the impact point of the beam in a circumferential direction around the longitudinal axis by controlling the rotation of the beam around the longitudinal axis.

[0043] A longitudinal position control element for controlling the longitudinal position of the impact point of the beam along the longitudinal direction defined by the longitudinal axis; and

[0044] A distance control element is used to control the distance between the source output and the tubular surface of the rod, thereby defining the beam length.

[0045] Therefore, the beam can be positioned by controlling the relative position of the control lever and the beam. Specifically, the lever rotates about its longitudinal axis, while the beam is positioned longitudinally and at a distance. Alternatively, an embodiment can be configured where the beam is positioned to rotate around the lever while the lever remains stationary. However, rotation of the lever is the preferred option because it simplifies the design of the device and reduces energy consumption during operation. Distance control allows for adaptation to the shape of the lever and positioning the beam's impact point according to its focal point.

[0046] Preferably, the rotation control element includes a servo motor operably connected to the rod to cause the rod to rotate about a longitudinal axis, such that the support can be rotated by a technical component that can be easily integrated into the printing device.

[0047] Preferably, the longitudinal position control element includes at least one straight longitudinal guide configured to longitudinally position the source output in a direction parallel to the longitudinal axis. As a non-limiting example, the position control element includes a straight longitudinal guide such that the laser can be moved along the straight longitudinal guide.

[0048] Preferably, the distance control element includes at least one straight lateral guide configured to laterally position the source output in a direction orthogonal to the longitudinal axis. As a non-limiting embodiment, the distance control element includes two parallel guides along which the aforementioned longitudinal guide is movable, and wherein each end of the longitudinal guide is attached to one of the parallel guides.

[0049] Preferably, the rod is arranged horizontally, the source output is arranged to emit the beam in a vertically downward direction, and the distance control element is configured to vertically position the source output. This arrangement is particularly advantageous when the rod is arranged to pass through a resin container with an opening at the top, allowing the beam to impact the tubular surface of the rod through the opening. Furthermore, this configuration allows for partial reuse of the Cartesian 3D printing equipment, where the electromagnetic radiation source (e.g., a laser) can be moved both vertically and horizontally. The above further facilitates the design of the 3D printing equipment of the present invention based on existing expertise in stereolithography equipment.

[0050] In an alternative embodiment, the rod is arranged vertically, the source output is arranged to emit the beam in a horizontal direction, and the distance control element is configured to horizontally position the source output. As an alternative to the previous embodiment, it also allows the reuse of known equipment to move the electromagnetic radiation source. Regarding these two exemplary embodiments, the choice of one or the other alternative embodiment will depend on characteristics, particularly the size of the rod, the object to be printed, and the space required to accommodate the printing equipment.

[0051] Preferably, the 3D printing apparatus further includes a layer measuring device configured to determine a thickness measurement of the layer of fluid resin provided on the tubular surface. The thickness of the polymerized resin layer corresponds to the fluid resin layer to be polymerized, excluding eventual shrinkage or expansion during the polymerization process. Therefore, measuring the thickness of the fluid resin layer on the tubular surface allows for the determination of the thickness of the polymerized resin layer.

[0052] Preferably, the layer measuring device includes a laser profiler, such that the thickness measurement is determined by the difference between the laser profiler's measurement when no fluid resin is applied to the tubular surface and the measurement when the fluid resin is applied to the tubular surface. Laser profilers are known in the art and offer good accuracy. In this case, measuring the thickness of the fluid resin layer involves two steps: first, the laser profiler is pointed at the tubular surface on which no fluid resin is applied, so the distance measured is from the profiler to the surface. Second, liquid resin is provided, and the laser profiler takes another measurement; in this case, the distance measured is from the profiler to the fluid resin. Therefore, the thickness of the resin layer can be determined using the difference between the two measurements. Those skilled in the art will understand that the specific calculation will depend on the positioning of the laser profiler and the rod. When the 3D tubular object to be created comprises more than one layer, equivalent thickness measurements of the second and subsequent layers can be obtained by comparison, not with the tubular surface itself, but with the already polymerized layers.

[0053] Preferably, the 3D printing equipment further includes a layer thickness control device configured to receive thickness measurements and, if necessary, change the thickness of the resin layer provided on the tubular surface. Therefore, not only can the thickness of the resin layer be known, but it can also be changed according to the requirements of the 3D tubular object to be printed from the model, particularly if the measured thickness differs from the thickness defined in the model, the layer thickness control device increases or decreases the thickness accordingly. The method of changing the thickness depends on the type of 3D printing equipment, the fluid resin used, how the resin is applied to the tubular surface, etc. Different options are conceivable, but preferably, the thickness is changed by at least one of the following:

[0054] Change the amount of resin supplied by the resin-supplying device;

[0055] Changing the temperature of the fluid resin; and

[0056] Change the rotational speed of the rod.

[0057] As a non-limiting embodiment, when the rod is horizontally arranged inside the tank, changing the amount of resin supplied in the tank affects the level of the fluid resin within the tank; therefore, if the tubular surface is below the level of the liquid resin, the thickness of the resin layer is affected. In other cases where the tubular surface is only partially immersed in the horizontal liquid resin, the fluidity of the resin can be altered by changing the temperature of the liquid resin, and thus the thickness of the layer when it is dragged to the polymerization point as the rod rotates can also be changed. Similarly, changing the rotational speed also affects the manner in which the fluid resin is dragged.

[0058] The present invention also relates to a 3D printing method for manufacturing a 3D tubular object from a build platform having an outer surface based on a printing model; the method includes creating one or more consecutive polymeric resin layers, wherein each polymeric resin layer is created by the following steps:

[0059] A fluid resin polymerized by electromagnetic radiation is provided on the outer surface of the construction platform;

[0060] According to the printing model, an electromagnetic radiation beam suitable for polymerizing the fluid resin is positioned toward the outer surface of the building platform to create the polymerized resin layer;

[0061] The build platform includes a rod having a longitudinal axis, the rod forming a tubular surface around the longitudinal axis such that the outer surface of the build platform is included in the tubular surface, and wherein the beam is variably positioned according to the printed model such that it strikes different points of the fluid resin located on at least a portion of the tubular surface of the rod.

[0062] The technical components and effects are the same as those of the equipment mentioned above, and will not be repeated below for the sake of simplicity.

[0063] Preferably, the step of positioning the beam toward the tubular surface of the rod according to the printed model includes positioning the beam by at least the following:

[0064] - Circumferential positioning around the longitudinal axis in the circumferential direction;

[0065] -Longitudinal positioning along the longitudinal direction defined by the longitudinal axis; and

[0066] - Preferably, the distance between the source output and the tubular surface of the rod is positioned to define the beam length.

[0067] Preferably, the method includes the additional step of creating one or more consecutive additional layers of polymeric resin, wherein each additional layer is created by the following steps:

[0068] - An additional fluid resin is provided on the tubular surface of the rod, the additional fluid resin being polymerizable by electromagnetic radiation;

[0069] - According to the printing model, an electromagnetic radiation beam suitable for polymerizing the additional fluid resin is variably positioned toward the tubular surface of the rod, such that it strikes different points of the fluid resin located on at least a portion of the tubular surface of the rod having a tubular shape, thereby creating the polymerized resin layer.

[0070] Therefore, this method enables the creation of 3D tubular objects, where each concentric layer can be made of a different polymeric resin, unlike known methods that use only one resin and where each successive layer is arranged on a continuous plane, for example, perpendicular to the longitudinal axis. Preferably, the method involves repeating the preceding steps with a fluid resin, additional fluid resins, or even other fluid resins or multiple resins. The application of multiple resins arranged in essentially concentric layers also makes it possible to manufacture objects for applications currently impossible in the field of 3D printing. Therefore, it holds promise as a subject for future research and development.

[0071] Preferably, the fluid resin, or additional fluid resin where appropriate, is propiolactone, PCL, a derivative compound, particularly PCL-diacrylate, a material that can be polymerized by ultraviolet radiation, and whose viscosity can be controlled by controlling its temperature, which makes it particularly advantageous in the case of the present invention.

[0072] Preferably, the fluid resin, or additional fluid resin where appropriate, is biocompatible, which allows them to be used in medical applications, such as for the manufacture of stents. A therapeutic product may optionally be added to at least one such resin, so that the 3D tubular object itself can have a therapeutic effect.

[0073] The present invention also relates to 3D tubular objects manufactured by the above-described 3D printing method.

[0074] The present invention also relates to tubular objects manufactured by 3D printing having at least one resin layer polymerized by electromagnetic radiation, wherein each of these polymerized resin layers has a tubular shape about a longitudinal axis, unlike objects currently obtainable by stereolithography, with each successive layer arranged concentrically about the longitudinal axis, particularly for creating high-resolution details less than 200 micrometers. This type of object offers the additional advantage of increased structural strength compared to objects made from overlapping planar layers. This type of object is unknown in the art and can also be printed using one of the preferred forms of production described above.

[0075] Preferably, the polymeric resin layer is formed of one or more biocompatible resins, and more preferably at least one of these resins has a therapeutic effect, which has the above-mentioned technical effects.

[0076] The present invention also relates to a printing model that defines a 3D tubular object that can be printed according to any of the preferred embodiments described above, comprising at least a model of a layer to be printed, wherein each point of the layer to be printed includes at least coordinates relative to:

[0077] - The angle of rotation about the longitudinal axis of the rod;

[0078] - The longitudinal position along the said longitudinal axis; and

[0079] - Preferably, the radial distance from the longitudinal axis.

[0080] The present invention also relates to a method of use according to any of the above preferred embodiments for manufacturing a stent.

[0081] The present invention also encompasses other detailed features illustrated in the detailed description of embodiments of the invention and the accompanying drawings. Attached Figure Description

[0082] Further advantages and features of the invention will be apparent in the following description, wherein preferred embodiments of the invention are disclosed with reference to the accompanying drawings, but without any limiting features:

[0083] Figure 1 This is a perspective view of one embodiment of the 3D printing device of the present invention.

[0084] Figure 2 yes Figure 1 Front view of the same implementation of the 3D printing equipment shown.

[0085] Figure 3 This is a detailed front view of a 3D printing apparatus according to one embodiment of the present invention, showing the portions corresponding to the electromagnetic radiation source, the beam, the rod, and the resin tank. A cross-section of the resin tank is shown to indicate the rod. The cross-sections are marked with parallel diagonals in the figure.

[0086] Figure 4A This is a detailed perspective view of a rod of a 3D printing apparatus according to one embodiment of the present invention, which has been used to manufacture 3D tubular objects, particularly supports still attached to the rod.

[0087] Figure 4B yes Figure 4A The equivalent view, but in different implementations, the rod is made of a solid block instead of a core and an outer layer.

[0088] Figure 5 yes Figure 8 A perspective view of the support after it has been removed from the rod of the 3D printing equipment.

[0089] Figure 6 This is a detailed front view of a 3D printing apparatus according to another embodiment of the present invention.

[0090] Figure 7 This is a detailed front view of the can and rod of a 3D printing apparatus according to another embodiment of the present invention.

[0091] Figure 8This is a detailed front view of a 3D printing apparatus according to one embodiment of the present invention, the apparatus having a laser profiler for measuring the thickness of a fluid resin layer on the tubular surface of a rod.

[0092] Figure 9 This is a front view of a 3D printing device according to another embodiment of the present invention.

[0093] Figure 10 This is a front view of a 3D printing device according to another embodiment of the present invention. Detailed Implementation

[0094] Some of the embodiments shown in the figures were fabricated using well-known stereolithography 3D printers, particularly the PRUSA MK2S, and have shown very positive results in laboratory experimental papers. Those skilled in the art will clearly recognize the modifications required for this invention. Future market versions will use different structures, and those skilled in the art will have no problem designing using the teachings of this document.

[0095] Figure 1 , 2 Figures 3 and 4 illustrate a first exemplary embodiment of the 3D printing apparatus 1 of the present invention. The 3D printing apparatus 1 is intended to manufacture at least one 3D tubular object 100 based on a printing model, which has a build platform containing an outer surface. For this first embodiment, the build platform is a rod 3 having a longitudinal axis 9, such as... Figure 3 As shown, rod 3 forms a tubular surface 2 around the longitudinal axis 9. Therefore, the outer surface of the platform is the tubular surface 2 of rod 3 and has a tubular shape around the longitudinal axis 9. As shown, the tubular surface 2 of rod 3 is rotationally symmetric about the longitudinal axis 9. Specifically, rod 2 is a cylinder, and the tubular surface 2 has a cylindrical shape.

[0096] The 3D printing equipment 1 also includes a resin supply device configured to provide a fluid resin 4, which can be polymerized by electromagnetic radiation, onto the tubular surface 2 of the rod 3. Specifically, the resin supply device includes a resin tank 12 arranged such that the rod 3 passes through the resin tank 12. Figure 3 As shown, the rod 3 is arranged horizontally such that all the tubular surfaces 2 are located below the resin loading height 13 in the resin tank 12.

[0097] The 3D printing equipment 1 is equipped with an electromagnetic radiation source 5, which is configured to emit an electromagnetic radiation beam 7 suitable for polymerizing the fluid resin 4 from a source output 6 onto the tubular surface 2 of the rod. In the first embodiment, the electromagnetic radiation source 5 is a laser 19 with a laser output, such that the source output 6 is the laser output. The laser beam 7 is indicated by a dashed line in the figure.

[0098] To position the beam 7, the 3D printing equipment also provides a beam positioning device 8, which is arranged to variably position the impact point of the beam 7 such that the light beam 7 impacts at different points on at least a portion of the fluid resin 4 provided on the tubular surface 2. Further, the 3D printing equipment 1 has a control device for controlling the beam positioning device 8 and the electromagnetic radiation source 5 according to the printed model to manufacture the 3D tubular object 100. For clarity, the control device is not shown in the figure. Figure 1 and Figure 2 The beam positioning device 8 is shown configured to variably position the impact point of the beam 7 on the fluid resin 4 using three positioning elements corresponding to three coordinates. First, circumferential positioning is performed in a circumferential direction around the longitudinal axis 9. This circumferential positioning is performed by a rotation control element 20, specifically a servo motor operably connected to a rod 3, which drives the rod 3 to rotate around the longitudinal axis 9. Second, longitudinal positioning is performed along a longitudinal direction defined by the longitudinal axis 9. This longitudinal positioning is performed by a longitudinal position control element 21, which has two parallel, straight longitudinal guides 211 configured to longitudinally position a laser 19 slidably mounted thereon, and correspondingly, position a source output 6. A longitudinal traction band 212 is used to slide the laser 19 longitudinally along the longitudinal guides 211. The longitudinal guides 211 are parallel to the rod 3 and the longitudinal axis 9, and the source output 6 is arranged to emit the beam 7 in a downward vertical direction perpendicular to the longitudinal axis 9. Third, the distance positioning between the source output 6 and the tubular surface 2 of the rod 3 is achieved by the distance control element 22, thereby determining the length of the beam 7. The distance control element 22 has four straight, transverse vertical guides 221 configured to laterally position the source output 6 in a direction perpendicular to the longitudinal axis 9. In the first embodiment, the vertical guides 221 are arranged vertically to vertically position the source output 6. Specifically, the vertical guides 221 are arranged two at a time at the two longitudinal ends of a longitudinal guide 211 to which it is slidably mounted. This allows the longitudinal guide 211 to slide up and down along the vertical guides 221, thus vertically positioning the source output 6.

[0099] The 3D printing equipment 1 of the first embodiment also provides a temperature control device. For clarity, the temperature control device is not shown in the figure, but rather a Peltier element is placed in the tank to control the temperature of the liquid resin 4.

[0100] In the first embodiment, laser 19 emits a beam 7 of ultraviolet (UV) radiation. Therefore, the 3D printing apparatus 1 can be used with a UV-polymerized resin. Specifically, a resin derived from polycaprolactone, such as PCL-diacrylate, can be used. However, within the scope of the invention, other types of electromagnetic radiation and fluid resins 4 are also conceivable, for example, in the case where laser 19 emits a beam 7 of infrared or visible light. Biocompatible resins 4, which may contain therapeutic additives, can also be used with the 3D printing apparatus of the present invention.

[0101] Using the 3D printing apparatus 1 of the embodiments described herein, a 3D printing method for printing 3D tubular objects may include several steps for creating continuous layers of polymeric resin. Each layer is created by providing a fluid resin 4, so it is conceivable to use different fluid resins 4 for different layers.

[0102] Figure 4A This is a detailed view of the rod 3 according to the first embodiment. In this case, the rod 3 has a steel core 10 encased in an outer layer 11 made of nylon forming the tubular surface 2 of the rod 3. Other metals, such as titanium, can be contemplated for the core 10. Furthermore, other elastomeric materials, such as latex, can also be contemplated for the outer layer 11. Figure 4A A 3D tubular object manufactured using 3D printing equipment 1 according to the 3D printing method of the present invention is shown, and it is still attached to the tubular surface 2. Figure 5 The same 3D tubular object is shown after it has been removed from rod 3. (See Figure 4 and...) Figure 5 In this case, the present invention has been used to manufacture 3D printed scaffolds. Figure 4B Different embodiments of the rod 3 are shown, which are made of a solid block rather than a core and an outer layer, and in which the tubular surface 2 is not made of a material different from the rest of the rod 3.

[0103] In the first embodiment, the tubular surface 2 of rod 3 is a diffuse surface that does not reflect the wavelength of the electromagnetic radiation. The tubular surface 2 of rod 3 is opaque to wavelength.

[0104] Other embodiments of the 3D printing apparatus according to the present invention are disclosed below. These embodiments share most of the features disclosed in the first embodiment described above. Therefore, only the distinguishing features will be described in detail. For the sake of brevity, common features shared with the first embodiment described above will not be described below.

[0105] Figure 6 A second embodiment of the 3D printing apparatus 1 according to the present invention is shown, wherein the electromagnetic radiation source 5 has an electromagnetic radiation generator 16 and an optical fiber guiding module 17 that guides the electromagnetic radiation to an optical fiber output, such that the source output 6 is the optical fiber output.

[0106] Figure 7 A third embodiment of the 3D printing apparatus 1 is shown, wherein the rod 3 is arranged horizontally. In this third embodiment, a portion of the tubular surface 2 is located above the resin loading height 13 in the resin tank 12, while another portion of the tubular surface 2 is located below the resin loading height 13.

[0107] Figure 8 A fourth embodiment of the 3D printing apparatus 1 is shown, wherein the rod 3 is arranged horizontally, and the tubular surface 2 is located below the resin loading height 13 in the resin tank 12. In this embodiment, the 3D printing apparatus 1 further includes a layer measuring device 40 configured to determine a thickness measurement of the layer of fluid resin 4 provided on the tubular surface 2. The layer measuring device 40 includes a laser profiler to determine the thickness measurement based on the difference between the measurement of the laser profiler when no fluid resin 4 is provided on the tubular surface 2 and the measurement when the fluid resin 4 is provided on the tubular surface 2. Furthermore, the apparatus includes a layer thickness control device configured to receive the thickness measurement and, if necessary, change the thickness of the resin layer provided on the tubular surface 2, in this case by changing the amount of fluid resin 4 provided by the resin providing device, i.e., the amount of fluid resin 4 provided in the resin tank 12. Other embodiments are conceivable, for example, from Figure 7 The third embodiment begins, and the layer thickness control device is configured to change the thickness by changing the temperature of the fluid resin 4 and / or changing the rotation speed of the rod 3.

[0108] Figure 9 A fifth embodiment of the 3D printing apparatus 1 is shown, wherein the rod 3 is arranged vertically, the source output 6 is arranged to emit a beam 7 in a horizontal direction, and the distance control element 22 is configured to horizontally position the source output 6. In this fifth embodiment, the resin tank 12 has a container 14 arranged around the rod 3, such that a resin chamber 15 is defined between the container 14 and the tubular surface 2 of the rod 3. In this fifth embodiment, the container 14 is made of a material that is transparent to the electromagnetic radiation emitted by the laser 19.

[0109] Figure 10A sixth embodiment of the 3D printing apparatus 1 is shown, wherein the rod 3 is arranged vertically and the source output 6 is arranged to emit a beam 7 in a horizontal direction. In this sixth embodiment, the resin tank 12 has a container 14 arranged around the rod 3, such that a resin chamber 15 is defined between the container 14 and the tubular surface 2 of the rod 3. The container 14 is made of a material transparent to the electromagnetic radiation emitted by the laser 19. In contrast to the previous embodiments, this sixth embodiment does not include a distance control element 22. Furthermore, instead of a rotation control element 20 acting on the rod 3, a source rotation element 30 acts on the laser 19, causing the source output 6 to move around the rod 3, particularly around the longitudinal axis 9. Figure 9 As shown, the source rotation element 30 includes a rotational structure rotatably mounted around the rod 3, with the longitudinal axis 9 arranged vertically in this case. A longitudinal control element 21 is fixed to the rotational structure such that, as the rotational structure rotates, it positions the beam 7 in a circular direction.

[0110] In other possible embodiments not shown in the figure, the tubular surface 2 of the rod 3 has rotational symmetry about the longitudinal axis 9, such that the tubular surface 2 has a conical or truncated conical shape.

Claims

1. A 3D printing apparatus (1) for manufacturing at least one 3D tubular object (100) based on a printing model. The 3D printing equipment (1) includes: - A construction platform with an outer surface; - A device for providing resin, configured to provide a fluid resin that can be polymerized by electromagnetic radiation on the outer surface of the building platform (4). - An electromagnetic radiation source (5) is configured to emit a beam (7) of electromagnetic radiation suitable for polymerizing the fluid resin (4) from the source output (6) toward the outer surface of the construction platform. - A beam positioning device (8) is configured to variably position the impact point of the beam (7) on the fluid resin (4) provided on the outer surface by at least the following means: - Circumferential positioning around the longitudinal axis (9) in the circumferential direction; - Longitudinal positioning along the longitudinal direction defined by the longitudinal axis (9); and - The distance between the source output (6) and the tubular surface (2) of the rod (3) is positioned to define the beam length; and - A control device configured to control the beam positioning device (8) and the electromagnetic radiation source (5) according to the printed model to manufacture the 3D tubular object (100). The construction platform is characterized by comprising a rod (3) having a longitudinal axis (9), the rod (3) forming a tubular surface (2) around the longitudinal axis (9), such that the outer surface of the construction platform is included in the tubular surface (2), and wherein the beam positioning device (8) is configured to variably position the impact point of the beam (7) at different points on at least a portion of the fluid resin (4) provided on the tubular surface (2), wherein the tubular surface of the rod is a diffuse surface of the wavelength of the electromagnetic radiation.

2. The 3D printing equipment (1) according to claim 1, characterized in that, The rod (3) includes a hard core (10) enclosed in an outer layer (11) made of an elastomeric material, the outer layer (11) forming the tubular surface (2) of the rod (3).

3. The 3D printing equipment (1) according to claim 2, characterized in that, The hard core (10) is made of steel.

4. The 3D printing apparatus (1) according to any one of claims 2 or 3, characterized in that, The elastomer material is latex or nylon.

5. The 3D printing apparatus (1) according to any one of claims 1 to 3, characterized in that, The apparatus for providing resin includes a resin tank (12) arranged such that the rod (3) passes through the resin tank (12).

6. The 3D printing equipment (1) according to claim 5, characterized in that, The rod (3) is arranged horizontally such that all the tubular surfaces (2) are located below the resin loading height (13) in the resin tank (12).

7. The 3D printing equipment (1) according to claim 4, characterized in that, The rod (3) is arranged horizontally such that a portion of the tubular surface (2) is above the resin loading height (13) in the resin tank (12) and another portion of the tubular surface (2) is below the resin loading height (13).

8. The 3D printing equipment (1) according to claim 5, characterized in that, The resin tank (12) includes a container (14) arranged around the rod (3) such that a resin chamber (15) is defined between the container (14) and the tubular surface (2) of the rod (3), the container (14) being made of a material that is transparent to the electromagnetic radiation.

9. The 3D printing apparatus (1) according to any one of claims 1 to 3, characterized in that, The rod (3) is rotatably mounted about the longitudinal axis (9), and the beam positioning device (8) includes: - Rotation control element (20) for controlling the circumferential positioning of the impact point of the beam (7) in the circumferential direction around the longitudinal axis (9) by controlling the rotation of the rod (3) about the longitudinal axis (9); - A longitudinal position control element (21) for controlling the longitudinal position of the impact point of the beam (7) along the longitudinal direction defined by the longitudinal axis (9); and - Distance control element (22) for controlling the distance between the source output (6) and the tubular surface (2) of the rod (3), thereby defining the beam length.

10. The 3D printing equipment (1) according to claim 9, characterized in that, The rod (3) is arranged horizontally, the source output (6) is arranged to emit the beam (7) in a vertically downward direction, and the distance control element (22) is configured to vertically position the source output (6).

11. The 3D printing equipment (1) according to claim 9, characterized in that, The rod (3) is arranged vertically, the source output (6) is arranged to emit the beam (7) in the horizontal direction, and the distance control element (22) is configured to position the source output (6) horizontally.

12. The 3D printing equipment (1) according to claim 1, characterized in that, It also includes a layer measuring device (40) configured to determine a thickness measurement of the layer of the fluid resin (4) provided on the tubular surface (2); and a layer thickness control device configured to receive the thickness measurement.

13. The 3D printing equipment (1) according to claim 12, characterized in that, The layer thickness control device is configured to change the thickness of the fluid resin layer provided on the tubular surface (2).

14. The 3D printing apparatus (1) according to any one of claims 12 or 13, characterized in that, To vary the thickness of the fluid resin layer provided on the tubular surface (2), the device includes at least one of the following: Change the amount of resin supplied by the resin-supplying device; Change the temperature of the fluid resin (4); and Change the rotational speed of the rod (3).

15. The 3D printing apparatus (1) according to any one of claims 12 or 13, characterized in that, The layer measuring device (40) includes a laser profiler, such that the thickness measurement value is determined by the difference between the laser profiler measurement value when no fluid resin (4) is provided on the tubular surface (2) and the laser profiler measurement value when the fluid resin (4) is provided on the tubular surface (2).

16. A 3D printing method for manufacturing a 3D tubular object (100) from a build platform having an outer surface based on a printing model; the method includes creating one or more consecutive polymeric resin layers, wherein each polymeric resin layer is created by the following steps: - A fluid resin polymerized by electromagnetic radiation (4) is provided on the outer surface of the construction platform. - According to the printing model, an electromagnetic radiation beam (7) suitable for polymerizing the fluid resin (4) is positioned toward the outer surface (2) of the building platform to create the polymerized resin layer; Its features are, The construction platform includes a rod (3) having a longitudinal axis (9), the rod (3) forming a tubular surface (2) around the longitudinal axis (9), such that the outer surface of the construction platform is included in the tubular surface (2), and wherein the beam (7) is variably positioned according to the printing model such that it impacts different points of the fluid resin (4) located on at least a portion of the tubular surface (2), the step of positioning the beam (7) toward the tubular surface (2) of the rod (3) according to the printing model includes positioning the beam (7) by at least the following manner: - Circumferential positioning around the longitudinal axis (9) in the circumferential direction; - Longitudinal positioning along the longitudinal direction defined by the longitudinal axis (9); and - The distance between the source output (6) and the tubular surface (2) of the rod (3) is positioned to define the beam length; Furthermore, the 3D tubular object (100) is obtained by removing a 3D object formed from one or more continuous polymeric resin layers on the tubular surface (2) from the rod (3), wherein the tubular surface of the rod is a diffuse surface of the wavelength of the electromagnetic radiation.

17. The 3D printing method according to claim 16, characterized in that, The step of positioning the beam (7) toward the tubular surface (2) of the rod (3) according to the printed model includes positioning the beam (7) by positioning the distance between the source output (6) and the tubular surface (2) of the rod (3) to define the beam length.

18. The 3D printing method according to claim 16, characterized in that, It includes the additional step of creating one or more consecutive additional layers of polymeric resin, wherein each additional layer is created by the following steps: - Additional fluid resin is provided on the tubular surface (2) of the rod (3), the additional fluid resin being polymerizable by electromagnetic radiation; - According to the printed model, an electromagnetic radiation beam (7) suitable for polymerizing the additional fluid resin is variably positioned toward the tubular surface (2) of the rod (3) such that it strikes different points of the fluid resin (4) located on at least a portion of the tubular surface (2) of the rod (3) having a tubular shape, thereby creating the polymerized resin layer.

19. The 3D printing method according to any one of claims 16 to 18, characterized in that, The fluid resin (4) is biocompatible and the 3D tubular object manufactured by the method is a scaffold.

20. A 3D tubular object manufactured by the method of any one of claims 16 to 18, wherein the 3D tubular object is a 3D object having a hollow interior region defined by a tubular surface and a polymeric resin extending over or partially over the tubular surface.

21. The 3D tubular object according to claim 20, comprising a single layer of polymeric resin.

22. The 3D tubular object according to claim 20, comprising a continuous concentric layer of polymeric resin.

23. The 3D tubular object of claim 22, wherein the concentric layers are made of different resins.

24. The 3D tubular object of claim 20, wherein the polymeric resin is biocompatible and the 3D tubular object is a scaffold.

Images