Multi-material device for additive synthesis by multi-photon polymerization

Abstract

Title: Multi-material device for additive synthesis by multi-photon polymerization The invention relates to a device (2) for additive synthesis by multi-photon polymerization at the level of a printing volume hereinafter called voxel (30), comprising a printing head (21) comprising a body (211) in which a plurality of channels (2111, 2112, 2113, 2114) are formed, each of the channels being configured to allow the flow of a polymerizable liquid (40), from an inlet to an outlet, characterized in that each of the channels of the plurality of channels comprises an inlet (2111a, 2112a, 2113a, 2114a) and an outlet (2111b, 2112b, 2113b, 2114b) distinct from those of the other channels and in that the device comprises an alignment module (22) configured to move the head printing so as to position the output of one channel of the plurality of channels opposite the voxel. Figure for abstract: Fig.4

Description

Title of the invention: Multi-material device for additive synthesis by multi-photonic polymerization Technical field

[0001] The present innovation relates to the field of three-dimensional (3D) printing and more particularly printing by additive manufacturing by multi-photonic polymerization. The present invention relates in particular to a multi-material printing device by multi-photonic polymerization. STATE OF THE ART

[0002] Additive manufacturing is widely applied to the construction of polymer, metal, and glass objects. The market for 3D printers using polymer additive manufacturing as a printing method is thus growing. Many methods are used and new materials are being developed to meet the constraints associated with different printing methods.

[0003] In this technological context, the so-called two-photon polymerization (2PP) process opens the way to new developments and applications. This process makes it possible to manufacture three-dimensional (3D) micro or nanostructures by laser writing. The two-photon process makes it possible to have a resolution of the order of a nanometer (nm). A resolution of this order is not, for example, accessible by a one-photon technology (illustrated in [Fig.lA]).

[0004] Multi-photon polymerization is based on the use of so-called femtosecond or picosecond lasers providing laser pulses of the order of a few femtoseconds to several picoseconds, in particular several hundred picoseconds. A microscope objective or more generally an optical system then makes it possible to generate a focal point which, when using a Gaussian beam, takes the form of a small focal volume, generally of the order of a micron but having a Gaussian-shaped power distribution.

[0005] It is in this small volume, called a voxel (illustrated in [Fig.lB]), created at the central part of the Gaussian distribution, that the two-photon polymerization occurs when a photosensitive resin is introduced there. Scanning this focal zone within the volume of the material allows the creation of a three-dimensional polymer structure with each laser pulse. In a later step of the process, the unpolymerized material can be removed by washing in a suitable solvent. Currently, two-photon printers operate in monomaterial and do not allow the resin supply to be quickly changed at this place. However, using several materials could open the way to multiple applications.

[0006] Although no commercially available two-photon machine currently allows multi-material printing, research teams have recently published on two-photon multi-material printing.

[0007] Among these presentations, there is a multi-material two-photon printing method consisting of a sequential manual process for building structures in which a first structure made of a first material is inscribed, followed by washing before introducing the second material for the subsequent step of the multi-material part. This method thus makes it possible to produce multi-materials, however it is very consuming in terms of printing time and raw material. In addition, realignment problems when changing the resin can be observed.

[0008] Another method, called the pallet process, involves using a movable linear stage in which several droplets of different resins are placed. This method has the advantage of reducing printing time and the amount of material used. However, the reaction time of the micro-stage and therefore the speed of material change is limited due to the inertia of the micro-stage. In addition, this method involves cleaning the uncured resins by blowing. This process of removing the uncured resin may not be sufficiently efficient depending on the shape and complexity of the 3D model.

[0009] Finally, there is another method consisting of using a microfluidic system. This multi-material system is based on a microfluidic chamber integrated into a laser lithography device. This system is scalable in terms of the number of materials and eliminates the need for numerous trips between the lithography instrument and the chemistry room, with tedious realignment steps between the two. However, the proposed system has several disadvantages. Indeed, a minimal time is required to clean the channels after the use of a first resin and the introduction of another resin into the system. In addition, the consumption of photosensitive resin is significantly increased. Finally, this system is large and therefore complicates its introduction into a 3D printing system.

[0010] An object of the present invention is therefore to propose a solution in order to improve 3D printing by multi-photonic polymerization, preferably multi-material, making it possible in particular to meet the requirements of an industrial process on at least one of the following aspects: definition, precision, complex designs, compactness, time saving, limitation of the consumption of raw materials and waste.

[0011] Other objects, features and advantages of the present invention will become apparent from the following description and accompanying drawings. It is understood that other advantages may be incorporated. SUMMARY

[0012] To achieve this objective, according to one embodiment, a device is provided for additive synthesis by multi-photon polymerization at the level of a printing volume hereinafter called voxel, comprising a printing head comprising a body in which a plurality of channels is formed and / or assembled, each of the channels being configured to allow the flow of a polymerizable liquid, from an inlet to an outlet, characterized in that each of the channels of the plurality of channels comprises an inlet and an outlet distinct from those of the other channels and in that the device comprises an alignment module configured to move the printing head so as to position the outlet of a channel of the plurality of channels opposite the voxel.

[0013] Thus, the invention proposes a solution for producing complex multi-material parts composed of two or more materials, by a compact, precise and modular process impossible to obtain with current machines using multi-photon polymerization printing. In addition, the handling time is reduced while greatly limiting the loss of raw materials during cleaning of the resins which can be expensive chemical products.

[0014] Another aspect relates to a system for additive synthesis by multi-photonic polymerization comprising the device, an optical system configured to generate the localized printing volume or voxel and which extends along an axis called the optical axis, the alignment module comprising an attachment system configured to cooperate with the optical system.

[0015] Thus, the invention proposes a solution to avoid handling and re-gluing errors when changing resin. Indeed, when changing resin on current machines, handling can lead to poor realignment which can lead to a loss of replacement of the position of the part for inscription with a new material.

[0016] Another aspect also relates to a method of printing by additive synthesis by multi-photonic polymerization implementing the system comprising: • a supply of the channels of a plurality of channels with different polymerizable liquids, • positioning a print head such that an output of a channel of the plurality of channels faces a voxel; • registration of a part of an object in the printing volume or voxel from a polymerizable liquid delivered by said channel; • moving an alignment module so as to position the output of another channel opposite the voxel; • registration of another part of an object in the printing volume or voxel from another polymerizable liquid delivered by the other channel. BRIEF DESCRIPTION OF THE FIGURES

[0017] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0018] [Fig.lA] [Fig.lA] schematically represents the one-photon polymerization printing focal volume.

[0019] [Fig.lB] [Fig.lB] schematically represents the two-photon polymerization printing focal volume.

[0020] [Fig.2A] [Fig.2B] Figures 2A and 2B represent views, respectively in 3D and in profile, of the print head according to an embodiment of the invention.

[0021] [Fig.3] [Fig.3] represents a view of the outlets of the channels of the print head according to an embodiment of the invention.

[0022] [Fig.4] [Fig.4] represents a view of the device positioned on an optical system such as for example a microscope objective according to one embodiment of the invention.

[0023] [Fig.5] [Fig.5] schematically represents the external elements connected to the device according to an example of the invention.

[0024] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications. DETAILED DESCRIPTION

[0025] Before beginning a detailed review of embodiments of the invention, optional features which may possibly be used in combination or alternatively are set out below:

[0026] According to one example, the print head is mounted to move in translation on the alignment module at least along one axis, called the translation axis. This thus makes it possible to align the desired output of the print head with the voxel.

[0027] According to one example, the outlets of the plurality of channels are positioned in an aligned manner along the translation axis. This makes it possible to have several outlets and therefore several materials at the outlet on a single degree of freedom. The translation thus makes it possible to align the outlet bringing the desired material and to easily change materials along a single axis.

[0028] According to one example, the alignment module comprises a control unit configured to adjust the print head between a plurality of positions, each of which is such that the output of a different channel is positioned opposite the voxel. This allows the output to be adjusted according to the desired material. Each position allows for a different material output, allowing for multi-material two-photon polymerization printing.

[0029] According to one example, each of the plurality of channels has an inlet cross-section at its inlet that is larger than an outlet cross-section at its outlet. Reducing the size of the channels allows for improved flow of fluids such as resins having high viscosity.

[0030] According to one example, the outlet section of each of the channels of the plurality of channels at each outlet is substantially circular and has a diameter less than or equal to 20 μm, preferably less than or equal to 1 μm, or even less than or equal to 2 μm. The diameter of the outlets of the channels may have a dimension close to a micrometer or substantially equal to 1 μm. This thus makes it possible, during the flow of a polymerizable liquid, to obtain at the outlet a drop making it possible to limit the loss of material.

[0031] According to one example, the body comprises a first portion and a second portion, each of the plurality of channels extending into the first portion and the second portion, the first portion and the second portion being connected at a junction, and wherein the alignment module is mounted on the first portion of the body of the print head. The configuration of the print head allows the polymerizable liquid to be simply brought to the voxel, taking into account the need to create a flow.

[0032] According to one example, the second portion extends from the junction to the outlets of the plurality of channels and in which the second portion has a cross-section at the junction, greater than or equal to, preferably strictly greater than, a cross-section at the outlets. The second portion makes it possible, thanks to its funnel-like shape, to converge the outlets towards a limited surface, thus limiting the movement necessary between each outlet along the transverse axis to change material. If the distance between each channel is limited, the printing time is also limited. In addition, the size of the print head is also limited.

[0033] According to one example, the attachment system comprises a through opening configured to at least partially insert the optical system. This makes it possible to attach the printing device to the voxel generation system, thereby limiting problems such as reattachment problems.

[0034] According to one example, the attachment system is an annular ring.

[0035] According to one example, comprising a plurality of tanks, each tank of the plurality containing a different polymerizable liquid and wherein the inlet of each of the channels is connected to a different tank. This therefore allows the device to perform multi-material printing.

[0036] According to one example, the first portion of the body of the print head is positioned relative to a plane parallel to the plane comprising the optical axis with an angle of between 20° and 80°, preferably between 30° and 70°. This makes it possible to have a sufficient angle allowing the flow of the polymerizable liquid while bringing the outlets of the channels as close as possible to the voxel.

[0037] According to one example, the second portion is positioned so as to have an angle with the first portion of between 100° and 160°, preferably between 110° and 150°.

[0038] According to one example, before feeding the channels, a step of inserting a luminescent component into at least one of the polymerizable liquids is carried out. This makes it possible to insert a small quantity of dye into the polymer of each channel in order to recognize the type of channel. In addition, this makes it possible to optimize the positioning of the print head so as to correctly align, automatically using an additional camera, the outputs facing the voxel.

[0039] In the remainder of the description, the term “on” does not necessarily mean “directly on”. Thus, when it is indicated that a part or member A is supported “on” a part or member B, this does not mean that the parts or members A and B are necessarily in direct contact with each other. These parts or members A and B may be either in direct contact or be supported on each other by means of one or more other parts. The same applies to other expressions such as, for example, the expression “A acts on B”, which may mean “A acts directly on B” or “A acts on B by means of one or more other parts”.

[0040] In the following detailed description, use may be made of terms such as "horizontal", "vertical", "longitudinal", "transverse", "upper", "lower", "top", "bottom", "front", "rear", "inner", "outer". These terms must be interpreted relatively in relation to the normal position of the device. For example, the transverse concept of the device is understood as being the alignment dimension of the plurality of channels.

[0041] In this patent application, when it is indicated that two parts are distinct, this means that these parts are separate. They are: - positioned at a distance from each other, and / or - mobile relative to each other and / or - integral with each other by being fixed by added elements, this fixing being removable or not.

[0042] A single-piece unit cannot therefore be made up of two separate parts.

[0043] In the present patent application, the term "integral" used to qualify the connection between two parts means that the two parts are linked / fixed relative to each other, according to all degrees of freedom, unless explicitly specified differently. For example, if it is indicated that two parts are integral in translation in a direction X, this means that the parts can be movable relative to each other except in the direction X. In other words, if one part is moved in the direction X, the other part performs the same movement.

[0044] The terms “substantially”, “approximately”, “of the order of” mean “to within 20%, preferably to within 10%” or, when it is an angular orientation, “to within 10°”. Thus, a direction substantially normal to a plane means a direction having an angle of 90+10° relative to the plane.

[0045] The term "primary extension dimension" is understood as the largest dimension of the object.

[0046] A reference will also be used whose transverse or front / back direction corresponds to the x axis, the longitudinal or right / left direction corresponds to the y axis and the vertical or up / down direction corresponds to the z axis.

[0047] In the present description, the term mobile corresponds to a rotational movement or a translational movement or even to a combination of movements, for example the combination of a rotation and a translation.

[0048] In the present description, the term polymerizable liquid or photopolymerizable liquid corresponds to a liquid which, upon contact with a light source, is capable of transforming into a polymer. A polymerizable liquid may, in a non-limiting manner, be an organic or organic-inorganic hybrid resin, comprising at least one photoinitiator and one or more monomers such as: pentaerythritol triacrylate, pentaerythritol tetraacrylate, 2-hydroxyethyl methacrylate, trimethylolpropane triacrylate, tripropylene glycol diacrylate, or a combination thereof.

[0049] In the present description, the term flow is understood as a movement of a liquid in a flow direction either by gravity or by mechanical or physical action such as the action of a pump.

[0050] The present invention relates to a device 2 used for printing by additive synthesis by multi-photon polymerization. More specifically, the present invention relates to a device 2 configured to deposit photosensitive resin also called polymerizable liquid 40 at the level of a printing volume called hereinafter voxel 30. The device 2 will now be described with reference to FIGS. 2A to [Fig.4].

[0051] The device 2 comprises a print head 21. The print head 21 is configured so as to bring at least one polymerizable liquid 40 to the voxel 30. The print head 21 comprises a body 211 in which a plurality of channels 2111, 2112, 2113, 2114 are formed. Each of the channels 2111, 2112, 2113, 2114 is configured to allow the flow E of a polymerizable liquid from an inlet to an outlet. A plurality of channels is understood to mean having at least two channels, in a non-limiting manner, FIGS. 2A to 4 represent a print head 21 having four channels 2111, 2112, 2113, 2114.

[0052] Each of the channels of the plurality of channels 2111, 2112, 2113, 2114 comprises an inlet 2111a, 2112a, 2113a, 2114a and an outlet 2111b, 2112b, 2113b, 2114b distinct from those of the other channels 2111, 2112, 2113, 2114. Thus, each of the channels 2111, 2112, 2113, 2114 can be independent. Similarly, each of the channels 2111, 2112, 2113, 2114 can allow the flow E of a different polymerizable liquid 40. Thus each of the channels 2111, 2112, 2113, 2114 can extend along a main extension dimension from its inlet 2111a, 2112a, 2113a, 2114a to its outlet 2111b, 2112b, 2113b, 2114b. Similarly, the flow E of the polymerizable liquid 40 extends from each of the inlets 2111a, 2112a, 2113a, 2114a, to each of the outlets 2111b, 2112b, 2113b, 2114b.

[0053] The device 2 also comprises an alignment module 22 configured to move the print head 21 so as to position the output 2111b, 2112b, 2113b, 2114b, of a channel 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 opposite the voxel 30.

[0054] According to one example, the print head 21 is mounted to move in translation on the alignment module 22 along an axis X, called the translation axis X. In addition, the outlets 2111b, 2112b, 2113b, 2114b of the plurality of channels 2111, 2112, 2113, 2114 are positioned in an aligned manner along the translation axis X. Thus, the outlets 2111b, 2112b, 2113b, 2114b are positioned side by side. The positioning along the translation axis X of the outputs 2111b, 2112b, 2113b, 2114b of the channels 2111, 2112, 2113, 2114 can make it possible to position one output among the outputs 2111b, 2112b, 2113b, 2114b of the plurality of channels 2111, 2112, 2113, 2114 opposite the voxel 30 and then to carry out a translation of the print head 21 to place another output among the outputs 2111b, 2112b, 2113b, 2114b opposite the voxel during printing. To do this, the alignment module 22 can comprise a control unit 221.

[0055] According to one example, the control unit 221 is configured so as to adjust the print head 21 between a plurality of positions. Each of the positions of the plurality of positions may be such that the outlet 2111b, 2112b, 2113b, 2114b of a different channel 2111, 2112, 2113, 2114 is positioned opposite the voxel 30. Thus, a single device 2 makes it possible to bring several polymerizable liquids to a voxel 30. 40 coming from the outputs 2111b, 2112b, 2113b, 2114b of the print head 21. The device 2 makes it possible to bring several polymerizable liquids 40, several different materials, up to a voxel 30, without change, without realignment or without cleaning between each polymerizable liquid 40. The production time of the printed object as well as the constraints of realignment thereof are then reduced compared to the devices presented in the prior art.

[0056] According to one example, the control unit 221 is a micro-positioning table by piezoelectric displacement. Thus, the control unit 221 allows nanometric adjustment at least along the translation axis X, of the outputs 2111b, 2112b, 2113b, 2114b of the channels 2111, 2112, 2113, 2114 opposite the voxel 30.

[0057] According to one example, the control unit 221 is a 3D micro-table for positioning by piezoelectric displacement. Thus, the control unit 221 allows nanometric adjustment along the translation axis X but also along the longitudinal and vertical axes. More precisely, the control unit 221 may comprise three piezoelectric shims making it possible to align the outputs 2111b, 2112b, 2113b, 2114b of the print head 21 along the transverse, longitudinal and vertical axes (x, y, z).

[0058] According to one example, each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 has an inlet section 2111a', 2112a', 2113a', 2114a' at its inlet 2111a, 2112a, 2113a, 2114a. Similarly, in one example, each of the plurality of channels 2111, 2112, 2113, 2114 has an outlet section 2111b', 2112b', 2113b', 2114b' at its outlet 2111b, 2112b, 2113b, 2114b. Each of the inlet sections 2111a', 2112a', 2113a', 2114a' may be substantially circular. Similarly, each of the outlet sections 2111b', 2112b', 2113b', 2114b' may be substantially circular. According to another aspect, each of the output sections 2111b', 2112b', 2113b', 2114b', may be substantially oval. The term oval is understood to mean a closed planar curve which has two perpendicular axes of symmetry.

[0059] According to one example, each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 has an inlet section 2111a', 2112a', 2113a', 2114a' at its inlet 2111a, 2112a, 2113a, 2114a, greater than an outlet section 2111b', 2112b', 2113b', 2114b' at its outlet 2111b, 2112b, 2113b, 2114b. Reducing the cross-section of each of the channels 2111, 2112, 2113, 2114 allows the polymerizable liquid 40 to flow into the plurality of channels 2111, 2112, 2113, 2114 while ensuring that the polymerizable liquid 40 size is of the order of the voxel size 30 at the outlets 2111b, 2112b, 2113b, 2114b. Thus, the quantity of polymerizable liquid 40 used is limited in order to avoid a significant loss of polymerizable material. The outlet cross-section 2111b', 2112b', 2113b', 2114b' of each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 at each outlet 2111b, 2112b, 2113b, 2114b may then have a diameter DI less than or equal to 20 pm (micrometer), preferably less than or equal to 100 pm. The size of a voxel 30 may have dimensions along the transverse (x) and longitudinal (y) axes of substantially 100 nm (nanometer) and of substantially 500 nm along the vertical axis (z), these dimensions may vary depending on the optical system used, the loss of polymerizable liquid 40 is then limited.

[0060] According to one example, the body 211 of the print head 21 comprises a first portion 21a and a second portion 211b. The channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 may extend into the first portion 21a and the second portion 211b.Similarly, according to one example, at least a portion, or a section of each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 extends in the first portion 211a. Similarly, according to one example, at least a portion, or a section of each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 extends in the second portion 211b. Each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 may be positioned parallel to each other in the first portion 211a. More specifically, a section of each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 may be positioned parallel to each other in the first portion 211a.

[0061] According to one example, the channels 2111, 2112, 2113, 2114 may extend partly outside the first portion 211a. More precisely, the inlets 211a, 2112a, 2113a, 2114a of the plurality of channels 2111, 2112, 2113, 2114 may be positioned outside the first portion 211a. Thus, the body 211 can form a housing for connecting the plurality of channels 2111, 2112, 2113, 2114. The body 211 can be composed of several elements and thus make it possible to assemble the plurality of channels 2111, 2112, 2113, 2114. The body 211 can thus have a first face 21 Id. The body 211 can have a second face 21 le opposite the first face. The body 211 can also have lateral faces 21 If connecting the first face 21 Id to the second face 21 le. The first portion 21 la of the body 211 could then have holes 211a' making it possible to assemble the body 211 in order to securely connect the plurality of independent channels 2111, 2112, 2113, 2114.Similarly, the holes 211a' make it possible to connect the first face 211d of the body 211 to the second face 211c of the body 211.

[0062] According to one example, the first portion 211a has a constant cross-section 211a. The first portion 211a may have a parallelepiped shape with a main extension dimension parallel to the main extension dimension channels 2111, 2112, 2113, 2114. Similarly, each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 has a cross-section in the first portion 211a substantially equal to the inlet section 2111a', 2112a', 2113a', 2114a' at their inlet 2111a, 2112a, 2113a, 2114a.

[0063] According to one example, the first portion 211a is fixed to the alignment module 22. Similarly, the alignment module 22 may be mounted at least in part on the first portion 211a of the body 211 of the print head 21. Similarly, at least a part of the alignment module 22 may be fixed to the first face 211d of the print head 21. In order to allow a flow E by gravity with sufficient pressure of the polymerizable liquid 40, the first portion 211a is fixed so as to have an inclination relative to a plane parallel to the ground. The first portion 211a may thus have an angle of inclination I relative to a plane parallel to the ground. The angle of inclination I may be between 0° and 90°. The angle of inclination I may be between 20° and 80°, preferably between 30° and 70°. It is understood that other angle ranges may be achievable.Similarly, the first portion 211a can thus have an angle of inclination I relative to a perpendicular plane comprising the translation axis X of between 0° and 90°, between 20° and 80°, preferably between 30° and 70°. It is understood that other angle ranges can be achieved.

[0064] Similarly, according to one example, the section of each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114, extending in the first portion 211a has an angle of inclination I relative to a plane parallel to the ground. The angle of inclination I may be between 20° and 80°, preferably between 30° and 70°.

[0065] According to one example, the first 211a and the second 211b portion are connected at a junction 211c. Thus, the first portion 211a may extend from the inputs 2111a, 2112a, 2113a, 2114a of the plurality of channels 2111, 2112, 2113, 2114 to the junction 211c. Similarly, the second portion 211b may extend from the junction 211c to the outputs 2111b, 2112b, 2113b, 2114b of the plurality of channels 2111, 2112, 2113, 2114.

[0066] According to one example, the second portion 211b has, along the translation axis X, a cross-section 211bl at the junction 211c, greater than or equal to a cross-section 21 lb2 at the plurality of outlets 2111b, 2112b, 2113b, 2114b. Preferably, the second portion 211b has, along the translation axis X, a cross-section 211bl at the junction 211c, strictly greater than a cross-section 21 lb2 at the plurality of outlets 2111b, 2112b, 2113b, 2114b. Similarly, the second portion 211b may thus have a substantially funnel shape. This reduction in transverse dimension of the second portion 211b allows the body 211 to have an outlet face 211g comprising the outlets 2111b, 2112b, 2113b, 2114b of the plurality of channels 2111, 2112, 2113, 2114 and having a dimension along the transverse axis X limited to the dimension of the outlets 2111b, 2112b, 2113b, 2114b. The print head 21 can then be compact.

[0067] According to one example, each of the channels 2111, 2112, 2113, 2114 in the second portion 211b extends from the junction 211c to the outlet face 211g. Each of the channels 2111, 2112, 2113, 2114 can thus be positioned so as to converge until they present their outlets 2111b, 2112b, 2113b, 2114b at the outlet face 211g.

[0068] According to one example, the outlets 2111b, 2112b, 2113b, 2114b are positioned on the outlet face 211g, preferably substantially at the level of the lower edge 211g of the outlet face 211g. The outlets 2111b, 2112b, 2113b, 2114b can thus be as close as possible to the voxel 30. The device 2 thus makes it possible to carry out multi-material printing.

[0069] According to one example, the second portion 211b is positioned so as to have an angle θ2 with the first portion 211a. The angle θ2 may be between 90° and 180°. The angle θ2 may be between 100° and 160°, preferably between 110° and 150°. It is understood that other ranges of angles may be achievable. The angle 02 allows the print head 21 to bring the polymerizable liquid 40 to the voxel 30. Similarly, according to one example, the section of each of the channels 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114, extending in the second portion 211b has an angle 02 with the section of each of the channels extending in the first portion 211b.

[0070] According to one example, the print head 21 may be printed by photopolymerization. In a non-limiting manner, the print head 21 may be printed in organic polymer resin such as acrylate, in organic-inorganic hybrid resin, the inorganic part of which comprises at least one inorganic compound such as a silica or alumina precursor. The print head 21 may also be made of metal, for example stainless steel or copper. The print head 21 may thus be produced by machining.

[0071] According to one example, the device 2 is configured so as to cooperate with an optical system 3. The optical system 3 may, according to one example, be a microscope objective. Thus, one can consider a system 1, illustrated in [Fig.4], and comprising the device 2 as well as an optical system 3. The optical system 3 is configured to generate the voxel 30 using a light source. The optical system 3 extends along an axis, called the optical axis Z. The optical axis Z may be vertical.

[0072] According to one example, the cooperation between the device 2 and the optical system 3 is achieved by the alignment module 22. Indeed, the alignment module 22 may comprise an attachment system 222. The attachment system 222 may then be configured to cooperate with the optical system 3. The cooperation of the device 2 with the optical system 3 allowing the generation of the voxel 30 makes it possible to keep the device 2 in a fixed vertical position relative to the optical system 3. There is therefore no movement of the device 2 which could cause a repositioning problem during printing, thus ensuring increased print quality compared to the prior art.

[0073] According to one example, the attachment system 222 comprises a through opening 2221 configured so as to insert the optical system 3. Similarly, the attachment system 222 can surround the optical system 3. Thus, the attachment system 222 can be configured so as to grip the optical system 3 in order to fix the device 2 to prevent movements along the optical axis Z. The attachment system 222 can be an annular ring.

[0074] According to one example, the attachment system 222 is fixed to the control unit 221. The attachment system 222 can thus fix in position, on the optical system 3, the print head 21 of the device 2. The print head 21 can thus have the outputs 2111b, 2112b, 2113b, 2114b of the plurality of channels 2111, 2112, 2113, 2114 opposite the voxel 30. Similarly, the print head 21 is positioned relative to a plane parallel to the plane comprising the optical axis Z with an angle θ1 of between 20° and 80°, preferably between 30° and 70°. It is understood that other angle ranges are achievable. In fact, this angle range considers that the printing produced by the print head 21 is carried out on the upper face of a substrate.

[0075] The printing can, according to one embodiment, be carried out on a part suspended above said substrate. Thus, the print head 21 is positioned relative to a plane parallel to the plane comprising the optical axis Z with an angle 01 greater than or equal to 70°, preferably greater than or equal to 90°, preferably greater than or equal to 110°. According to this embodiment, the print head 21 of the device 2 is fixed on an ancillary support not shown. The ancillary support can be positioned parallel to the plane comprising the optical axis Z. The print head 21 can then be fixed to the ancillary support via the alignment module 22. Indeed, the alignment module 22 can comprise an attachment system 222. The attachment system 222 can be secured to the control unit 221. The attachment system 222 can thus fix the print head 21 of the device 2 in position on the ancillary support.

[0076] According to one example, the system 1 comprises a plurality of tanks 4, illustrated in [Fig. 5]. Each tank 4 of the plurality of tanks 4 may contain a liquid polymerizable 40 different. A tank 4 among the plurality of tanks 4 may contain a solvent allowing the cleaning of the object printed by the print head 21.

[0077] According to one example, at least one and preferably each of the liquids polymerizable liquids 40 contained in the plurality of tanks 4 may have a photoluminescent molecule. This photoluminescent molecule may allow the polymerizable liquid 40 to be optimally positioned in the voxel 30. More precisely, the photoluminescent polymerizable liquid 40 may be detected by a camera present in the optical system 3. The synergy of the camera and the photoluminescence may then allow the automatic adjustment of the channel in front of the voxel 30 by maximizing the intensity of the photoluminescence. Preferably, the photoluminescent molecules of the liquids of at least two channels are different so as to produce illuminations that can be differentiated by the camera.

[0078] According to one example, the inlets 2111a, 2112a, 2113a, 2114a of each of the channels 2111, 2112, 2113, 2114 are connected to a tank 4 different from the plurality of tanks 4. Thus, according to one example, the inlet 2111a of a first channel 2111 is connected to a tank 4 containing a polymerizable liquid, the inlet 2112a of a second channel 2112 is connected to a tank 4 containing a second polymerizable liquid 40, the inlet 2113a of a third channel 2113 is connected to a tank 4 containing a third polymerizable liquid 40, the inlet 2114a of a fourth channel 2114 is connected to a tank 4 containing a fourth polymerizable liquid 40.

[0079] According to one example, the polymerizable liquid 40 present in the plurality of tanks 40 is pressurized by a flow supply and control circuit 5 so as to flow to the inlets 2111a, 2112a, 2113a, 2114a of the plurality of channels 2111, 2112, 2113, 2114 and then to the outlets 2111b, 2112b, 2113b, 2114b of the plurality of channels 2111, 2112, 2113, 2114. The circuit 5 can activate the pressure for a single tank 40 so as to have the flow E of only one polymerizable liquid 40 at a time. The system 1 can thus perform multi-material printing.

[0080] According to one example, the method of printing by additive synthesis by multi-photonic polymerization implementing the system 1 comprises: • a supply of the channels 2111, 2112, 2113, 2114 of a plurality of channels 2111, 2112, 2113, 2114 with different polymerizable liquids 40, • positioning a print head 21 so that an output 2111b, 2112b, 2113b, 2114b of a channel 2111, 2112, 2113, 2114 of the plurality of channels 2111, 2112, 2113, 2114 faces a voxel 30; • registration of a part of an object in the printing volume or voxel 30 from a polymerizable liquid 40 delivered by said channel 2111, 2112, 2113, 2114; • moving an alignment module 22 so as to position the output 2111b, 2112b, 2113b, 2114b of another channel 2111, 2112, 2113, 2114 opposite the voxel; • registration of another part of an object in the printing volume or voxel 30 from another polymerizable liquid 40 delivered by the other channel 2111,2112,2113,2114.

[0081] According to one example, before feeding the channels 2111, 2112, 2113, 2114, a step of inserting a luminescent component into at least one of the polymerizable liquids 40 is carried out. This makes it possible to insert a small quantity of dye into the polymerizable liquid 40 of at least one channel and preferably of each channel 2111, 2112, 2113, 2114, in order to recognize the type of channel. In addition, this makes it possible to optimize the positioning of the print head 21 so as to correctly align, and this automatically thanks to an additional camera, the outputs 2111b, 2112b, 2113b, 2114b facing the voxel 30.

[0082] According to one example, the inscription of a part of an object involves the polymerization by light coming from the optical system 3 of a polymerizable liquid 40.

[0083] DIGITAL REFERENCES 1: System 2: Device 21: Print head 211: body 2111: channels / first channel 211 la: first channel input 2111a': input section 2111b: first channel output 2111b': output section 2112: channels / second channel 2112a: second channel input 2112a': entrance section 2112b: second channel output 2112b': output section 2113: channels / third channel 2113a: third channel input 2113a': input section 2113b: third channel output 2113b': output section 2114: channels / fourth channel 2114a: fourth channel input 2114a': entrance section 2114b: fourth channel output 2112b': output section 21 la: first portion 211al: cross section first portion 211a': hole 211b: second portion 211bl: cross section of second portion at the junction 211b2: cross section of second portion at the exits 211c: junction 21 Id: first side 211th: second side 21 If: side faces 211g: output face 22: Alignment module 221: Control unit 222: Attachment system 2221: through opening 3: optical system 30: Voxel 4: tanks 40: polymerizable liquid 5: Power supply and flow control circuit X: translation axis Z: optical axis I: angle of inclination of the first portion 01: angle between a plane parallel to the optical axis and the first portion 02: angle between the first portion and the second portion E: flow

Claims

Claims

1. Device (2), for additive synthesis by multi-photon polymerization at the level of a printing volume hereinafter called voxel (30), comprising a printing head (21) comprising a body (211) in which a plurality of channels (2111, 2112, 2113, 2114) is formed, each of the channels (2111, 2112, 2113, 2114) being configured to allow the flow (E) of a polymerizable liquid (40), from an inlet to an outlet, characterized in that each of the channels (2111, 2112, 2113, 2114) of the plurality of channels (2111, 2112, 2113, 2114) comprises an inlet (2111a, 2112a, 2113a, 2114a) and an outlet (2111b, 2112b, 2113b, 2114b) distinct from those of the other channels (2111, 2112, 2113, 2114) and in that the device (2) comprises an alignment module (22) configured to move the print head (21) so as to position the outlet (2111b, 2112b, 2113b, 2114b) of a channel (2111, 2112, 2113, 2114) of the plurality of channels (2111, 2112, 2113,2114) next to voxel (30).

2. Device (2), according to the preceding claim, in which the print head (21) is mounted movable in translation on the alignment module (22) at least along one axis, called the translation axis (X).

3. Device (2) according to the preceding claim, in which the outlets (2111b, 2112b, 2113b, 2114b) of the plurality of channels (2111, 2112, 2113, 2114) are positioned in an aligned manner along the translation axis (X).

4. A device (2) according to any preceding claim, wherein the alignment module (22) comprises a control unit (221) configured to adjust the print head (21) between a plurality of positions which are each such that the outlet (2111b, 2112b, 2113b, 2114b) of a different channel (2111, 2112, 2113, 2114) is positioned opposite the voxel (30).

5. Device (2) according to any one of the preceding claims, wherein each of the channels (2111, 2112, 2113, 2114) of the plurality of channels (2111, 2112, 2113, 2114) has an inlet section (2111a', 2112a', 2113a', 2114a') at its inlet (2111a, 2112a, 2113a, 2114a), greater than an outlet section (2111b', 2112b', 2113b', 2114b') at its outlet (2111b, 2112b, 2113b, 2114b).

6. Device (2) according to the preceding claim wherein the outlet section (2111b', 2112b', 2113b', 2114b') of each of the channels (2111, 2112, 2113, 2114) of the plurality of channels (2111, 2112, 2113, 2114) at each outlet (2111b, 2112b, 2113b, 2114b) is substantially circular and has a diameter (Dl) less than or equal to 20 μm, preferably less than or equal to 10 μm.

7. A device (2) according to any preceding claim, wherein the body (211) comprises a first portion (211a) and a second portion (211b), each of the channels (2111, 2112, 2113, 2114) of the plurality of channels (2111, 2112, 2113, 2114) extending through the first portion (211a) and the second portion (211b), the first portion (211a) and the second portion (211b) being connected at a junction (211c), and wherein the alignment module (22) is mounted on the first portion (211a) of the body (211) of the print head (21).

8. Device (2) according to the preceding claim, wherein the second portion (211b) extends from the junction (211c) to the outlets (2111b, 2112b, 2113b, 2114b) of the plurality of channels (2111, 2112, 2113, 2114) and wherein the second portion (211b) has a cross-section (211b) at the junction (211c), strictly greater than a cross-section (211b2) at the outlets (2111b, 2112b, 2113b, 2114b).

9. System (1) for additive synthesis by multi-photon polymerization comprising the device (2) according to any one of the preceding claims, an optical system (3) configured to generate the localized printing volume or voxel (30) and which extends along an axis, called the optical axis (Z), the alignment module (22) comprising an attachment system (222) configured to cooperate with the optical system (3).

10. System (1) according to the preceding claim, in which the attachment system (222) comprises a through opening (2221) configured so as to at least partially insert the optical system (3).

11. System (1) according to any one of the two preceding claims in which the attachment system (222) is an annular ring.

12. A system (1) according to any one of claims 9 to 11 comprising a plurality of tanks (4), each tank (4) of the plurality containing a different polymerizable liquid (40) and in which the inlet (2111a, 2112a, 2113a, 2114a) of each of the channels (2111, 2112, 2113, 2114) is connected to a different tank (4).

13. System (1) according to any one of claims 9 to 12, comprising a device according to claim 7 or claim 8, wherein the first portion (211a) of the body (211) of the print head (21) is positioned relative to a plane (x, z) parallel to the plane comprising the optical axis (Z) with an angle (01) between 20° and 80°, preferably between 30° and 70°.

14. System (1) according to any one of claims 9 to 13, comprising a device according to claim 7 or claim 8, in which the second portion (211b) is positioned so as to have an angle (02) with the first portion of between 100° and 160°, preferably between 110° and 150°.

15. A method of printing by additive synthesis by multi-photonic polymerization implementing the system (1) according to any one of claims 9 to 14 comprising: • a supply of the channels (2111, 2112, 2113, 2114) of a plurality of channels (2111, 2112, 2113, 2114) with different polymerizable liquids (40), • a positioning of a print head (21) so that an outlet (2111b, 2112b, 2113b, 2114b) of a channel (2111, 2112, 2113, 2114) of the plurality of channels (2111, 2112, 2113, 2114) is opposite a voxel (30); • registration of a part of an object in the printing volume or voxel (30) from a polymerizable liquid (40) delivered by said channel (2111, 2112, 2113, 2114); • displacement of an alignment module (22) so as to position the output (2111b, 2112b, 2113b, 2114b) of another channel (2111, 2112, 2113, 2114) opposite the voxel (30);• registration of another part of an object in the printing volume or voxel (30) from another polymerizable liquid (40) delivered by the other channel (2111,2112, 2113,2114).; 20

16. Method of printing by additive synthesis by multi-photonic polymerization according to the preceding claim, in which, before feeding the channels (2111, 2112, 2113, 2114), a step of inserting into at least one of the polymerizable liquids (40) a luminescent component is carried out.

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