Print head for a system for three-dimensional printing of material

Abstract

The present invention relates to a print head (10) for a system (1) for three-dimensional printing of material, said head comprising a main body (12) provided with an inlet opening (13) and with an outlet opening (14), through which openings the material to be printed passes, said head further comprising means (30) for closing the outlet opening, characterized in that the closing means comprise a rotor (32) associated with a motor element (38), a stator (34), and a tubular membrane (36) fixed by one end to the rotor and by the other end to the stator.

Description

PRINTHEAD FOR A THREE-DIMENSIONAL PRINTING SYSTEM

[0001] The present invention relates to the field of 3D printing and in particular the 3D printing of material for construction. Prior art

[0002] 3D printing of construction material such as concrete or mortar is known to design construction elements or even buildings. This 3D printing consists of having a vat of material. A pump is used to bring said material from the vat to a print head. This print head includes an opening-closing means used to allow or block printing. This opening-closing means is used when creating an object / building. Indeed, it is sometimes necessary to interrupt printing during construction in order to form openings or for the creation of complex parts with discontinuities.

[0003] The disadvantage of existing systems is that the process of stopping and restarting printing results in poor print quality. This poor quality is the result of the fact that, upon restart, the pressure in the printing system is not instantly restored to its operating value. As a result, the material stream deposited during this period is not of high quality, its dimensions do not conform to the desired dimensions, i.e. the material stream is thinner. This results in a construction that may have more fragile areas.

[0004] There is therefore a need to find a solution to this problem of the quality of material deposition.

[0005] The present invention seeks to solve the problems of the prior art by providing a printing system that allows a constant flow of output to be maintained when pausing said printing.

[0006] In this respect, the invention relates to a print head for a system for printing material in three dimensions, said head comprising a main body provided with an opening and an outlet through which the material to be printed passes, said head further comprising means for closing the outlet opening, characterized in that the closing means comprise a rotor associated with a motor element, a stator and a tubular membrane fixed by one end to the rotor and by the other end to the stator.

[0007] In one example, the rotor and stator are circular and concentric.

[0008] In one example, the main body is a conduit acting as a stator.

[0009] According to one example, the main body is a conduit, the rotor being arranged to surround said main body.

[0010] According to one example, the membrane has a cylindrical or conical shape or comprises two cylindrical portions of different diameters connected by a conical portion.

[0011] According to one example, the rotor or the stator are mounted to move in translation, the translational mobility being controlled by damping means.

[0012] According to one example, the damping means comprise at least one spring, preferably several springs, even more preferably, a series of regularly distributed springs.

[0013] In one example, the membrane is attached to the rotor and / or stator by a clamping ring.

[0014] In one example, the clamping ring has a rounded profile.

[0015] According to one example, the clamping ring comprises means for holding the ring comprising at least one hole and one stud arranged, respectively, on the clamping ring and on the inner conduit or vice versa.

[0016] The invention further relates to a three-dimensional printing device comprising a material reservoir connected to a print head via a pipe, said print head being carried by a structure allowing said print head to move along at least three axes: length, width and height, said printing device being controlled by a computing unit, characterized in that said print head is the print head according to the invention. Description of the drawings

[0017] Other features and advantages will become clear from the description given below, for information purposes only and in no way limiting, with reference to the attached drawings, in which:

[0018] - represents a view of a printing system according to the invention;

[0019] - represents a diagram of the printing system according to the invention;

[0020] - represents a print head of the printing system according to the invention;

[0021] - leset 5 represent means for closing the print head according to the invention;

[0022] - represents different versions of a membrane of a print head of the printing system according to the invention;

[0023] - 9 represent configurations of the printing system according to the invention;

[0024] - represents a variant of the print head with dampers according to the invention;

[0025] - figures 11 and 12 represent a variant of a clamping ring of a print head according to the invention. Detailed description

[0026] At, a system 1 for printing material in three dimensions is shown. The printing system 1 is used to produce a construction object such as a brick or a concrete block or to directly produce a building. The printing system comprises a print head 10 through which the material is deposited. The print head 10 is mounted on a structure 2 allowing said print head 10 to move along at least three axes: length, width and height to carry out said printing. This structure 2 may be in the form of an articulated arm or gantries. The print head 10 and the structure 2 are connected to a control unit.

[0027] The print head 10, visible in the, is connected to a reservoir 20 via a conduit called the main conduit 40. The reservoir 20 is a tank in which the mixture used for printing is stored. The reservoir 20 is also called a mixer when it is equipped with means for mixing the mixture such as an endless screw or rotating blades.

[0028] The printing system 1 further comprises a pump 50 for bringing the mixture from the reservoir to the print head. The whole is controlled by a control unit 60.

[0029] The print head 10, visible in the, comprises a main body 12 provided with an inlet 13 through which the main conduit is connected and an outlet 14 through which the material is ejected to be printed. The print head further comprises sealing means 30 arranged at the outlet allowing the material to be printed or not.

[0030] According to the invention, the closure means 30 comprise a rotor 32 and a stator 34 as seen in the figure. The closure means 30 further comprise a membrane 36. This membrane 36 is fixed both to the stator 34 and to the rotor 32. The rotor 32 and the stator are arranged to be one inside the other, that is to say concentric, and thus form an inner element and an outer element. Preferably, the rotor and the stator are circular in shape. It is possible for the rotor 32 and / or the stator 34 to be at least hexagonal in shape, for example octagonal or dodecagonal.

[0031] Rotating the rotor relative to the stator allows the membrane 36 to be moved and rotated. This rotation of the membrane 36 causes it to overlap on itself, resulting in the appearance of folds 360 allowing the membrane to simulate an iris as seen in the.

[0032] The membrane 36 used is a tubular type membrane. This membrane 36 has a cylindrical or conical or other shape such as for example a shape comprising two portions of different diameters connected together by a conical portion as visible in the.

[0033] This membrane 36 is fixed to the rotor and the stator in a clever manner. For this purpose, it is considered that the membrane 36 comprises an outer face and an inner face. The tubular stator 34 and rotor 32 also comprise an inner face and an outer face. The membrane 36 is then fixed to the rotor 32 and the stator 34 so that the outer face of the membrane 36 is in contact with the inner face of the rotor / stator element arranged as the inner element. The membrane 36 is then fixed to the rotor 32 and the stator 34 so that the outer face of the membrane 36 is in contact with the outer face of the rotor / stator element arranged as the outer element. For this purpose, the membrane 36 is turned over. For this purpose, the membrane 36 is first fixed to the inner element acting as the rotor 32 or the stator 34 and then is turned over, folded back on itself for its fixing to the outer element.The membrane 36 is fixed by various fixing means as shown in the figure.

[0034] An example of a fastening means is a clamping ring. This clamping ring can be screwed directly to the rotor or stator or comprise two portions that screw together. Another example is to screw the membrane to the rotor and the stator.

[0035] The membrane 36 is fixed so that it is taut once in place.

[0036] In a first embodiment visible in the, the main body 12 is in the form of a conduit, that is to say a tubular part. This main body 12 is the stator 34. The print head then comprises a rotor 32. This rotor 32 is in the form of a tubular part which surrounds the stator 34. The rotor 32 is mounted in rotation by means of a motor. This motor 38 is controlled by the control unit. In this first embodiment, the material is thus expelled by said stator 34.

[0037] In a second embodiment visible in the, the main body 12 is in the form of a conduit, that is to say a tubular part. The rotor 32 is a conduit which surrounds the main body, the two conduits being circular allowing the rotor to be rotated. The stator 34 is a fixed conduit, fixed to the main body 12 for example. In this second embodiment, the material is thus expelled through the main conduit 12.

[0038] Of course, the main body 12 is not necessarily in the form of a conduit. This conduit shape may be limited to the part at which the outlet opening is made. The main body 12 may thus be in the form of a square or rectangle or triangle from which a circular conduit forming the outlet extends.

[0039] The motor 38 used for rotating the rotor 32 is preferably a stepper motor. Such a motor allows fine, step-by-step rotation, thus opening or closing the membrane precisely.

[0040] The advantage of the system according to the invention is that it allows a start-stop phase without loss of pressure.

[0041] In a variant, one of the conduits is mounted on a damper as seen in the figure. Indeed, during the deformation of the membrane 36, a traction is exerted on said external conduit. So that the traction is not localized only on the membrane, the rotor 32 or the stator 34 are mounted on a damper. Preferably, the conduit mounted on the damper is the external conduit. The assembly then consists of having an external conduit fixed to a fixed point by a series of damping elements such as springs. Thus, when the rotor 32 rotates, the membrane 36 closes and extends. This extension of the membrane 36 causes a tension. The presence of the springs makes it possible to compensate for this tension since instead of having the tension which is localized on the membrane 36, this tension is compensated by the springs which allow the conduit mounted on springs to move.The springs allow, when the rotor rotates in the opposite direction, the membrane to relax and therefore a return to the initial position of the spring-mounted conduit.

[0042] In a variant, the membrane 36 is fixed to the inner duct by a clamping ring 39. This clamping ring 39 has a rounded shape as shown in the figure. This rounded shape protects the membrane. In fact, when stretched, the membrane 36 presses against and rubs against the edge of the inner duct. With the rotation of the membrane 36, this pressure can damage said membrane. The rounded clamping ring limits friction on the membrane.

[0043] The clamping ring 39 is, optionally, associated with means for holding the ring. Indeed, when the membrane 36 of the closure means 30 is closed, a residual pressure in the print head 10 or in the main conduit 40 may be present. This residual pressure tends to exert a stress on the clamping ring 39 which can lead to an axial translation of said clamping ring 39. This then results in a decoupling of the clamping ring with the membrane 36. To avoid this, the means for holding the ring comprise are arranged to limit this axial translation. In a first example, the means for holding the ring comprise at least one hole 39b, through or not, and a stud 39a arranged on the clamping ring 39 and on the inner conduit (which may be the stator 34) as visible in the.The stud and the hole are arranged so that said stud fits into the hole, even with the membrane inserted between said stud and the hole. This stud-hole assembly makes it possible to create a stop which limits the translation of the clamping ring. It is understood that the stud is arranged on the clamping ring and the hole on the inner duct or vice versa. In a second example, the inner duct may comprise at least one bead which limits the translation of the clamping ring.

[0044] Of course, the present invention is not limited to the illustrated example but is susceptible to various variants and modifications which will appear to those skilled in the art.

Claims

Print head (10) for a three-dimensional printing system (1) of material, said head comprising a main body (12) provided with an inlet opening (13) and an outlet opening (14) through which the material to be printed passes, said head further comprising means (30) for closing the outlet opening, characterized in that the closing means comprise a rotor (32) associated with a motor element (38), a stator (34) and a tubular membrane (36) fixed by one end to the rotor and by the other end to the stator. Print head according to the preceding claim, in which the rotor (32) and the stator (34) are circular and concentric. A print head according to claim 1 or 2, wherein the main body is a conduit acting as a stator. A print head according to either of claims 1 or 2, wherein the main body is a conduit, the rotor being arranged to surround said main body. Print head according to one of the preceding claims, in which the membrane (36) has a cylindrical or conical shape or comprises two cylindrical portions of different diameter connected by a conical portion. Print head according to one of the preceding claims, in which the rotor or the stator are mounted to move in translation, the translational mobility being controlled by damping means. Print head according to the preceding claim, in which the damping means comprise at least one spring, preferably several springs, even more preferably, a series of regularly distributed springs. Print head according to one of the preceding claims, wherein the membrane is fixed to the rotor and / or the stator by a clamping ring (39). Print head according to the preceding claim, in which the clamping ring has a rounded profile. Print head according to the preceding claim, in which the clamping ring comprises means for holding the ring comprising at least one hole (39b) and one stud (39a) arranged, respectively, on the clamping ring (39) and on the inner conduit or vice versa. Three-dimensional printing device (1) comprising a material reservoir connected to a print head via a pipe, said print head being carried by a structure allowing said print head to move along at least three axes: length, width and height, said printing device being controlled by a computing unit, characterized in that said print head is the print head according to one of the preceding claims.

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