Printing device for additive manufacturing process having material supply screw device

Abstract

The invention relates to a print head for an additive manufacturing process, the print head comprising a material supply device with a material transport screw, the material supply device being designed or rather constructed so that the screw and its drive can be inserted and replaced flexibly and cost-effectively. The invention also relates to a printing apparatus for an additive manufacturing process, comprising at least one print head according to the invention.

Description

[Technical Field]

[0001] The invention relates to a print head for an additive manufacturing process, the print head comprising a material supply device with a material transport screw, the material supply device being designed or rather constructed so that the screw and its drive can be inserted and replaced flexibly and cost-effectively. The invention also relates to a printing apparatus for an additive manufacturing process, comprising at least one print head according to the invention. [Background technology]

[0002] Printheads and corresponding printing devices for additive manufacturing processes in which particulate starting materials are used are known in the prior art. Summary of the Invention [Problem to be solved by the invention]

[0003] Such printheads generally consist of a print nozzle and an apparatus for supplying material to the print nozzle, typically an extrusion screw (also referred to herein as a "material delivery screw"). Exemplary disclosures include US2017 / 0008230A1 and a review article on pellet extruders by Shaik et al. (2021) in Open Access Library Journal 8:e7698.

[0004] In additive manufacturing processes such as 2D printing and 3D printing, which generally involve computer-controlled positioning of printing material on the print table of a printing device, a challenge exists, particularly in the field of printing objects containing active ingredients in the pharmaceutical and / or food supplement sector, in that printing devices intended to achieve individual delivery of active ingredients must be as easy to set up and cost-effective to operate as possible. [Means for solving the problem]

[0005] The technical problem of the present invention is to provide a print head and a printing device for additive manufacturing processes that can be produced cost-effectively in terms of material supply and that ensures a simple and versatile supply of replacement parts.

[0006] The above technical problem is solved by the protective claims and the embodiments of the present invention disclosed in the present description and the accompanying drawings.

[0007] Specifically, the present invention provides a print head for an additive manufacturing process, the print head comprising: - a print nozzle; a material supplying device, the material supplying device having (i) at least one material conveying screw configured to supply particulate printing material into the printing nozzle by rotational movement about a longitudinal axis, and (ii) at least one drive device for at least one of the material conveying screws, a proximal end of at least one of the material conveying screws is driven by the driving tool, and a distal end of the material conveying screw conveys the printing material into the printing nozzle; The at least one material conveying screw (5) has a standard or self-tapping thread at least in a portion including the distal end of the at least one material conveying screw.

[0008] The printhead according to the present invention may comprise two or more print nozzles and two or more material supply devices, each having one of the material transport screws defined according to the present invention and its drive device.

[0009] The print head and additional products of the invention are preferably designed for additive manufacturing by hot melt extrusion (HMT), more preferably by FDM (filament deposition modeling). It is particularly preferred that the print head and additional products of the invention are designed for additive manufacturing, preferably by FDM, of pharmaceutical, nutraceutical and / or food supplement products, in particular dosage forms, more preferably oral dosage forms.

[0010] The material conveying screw preferably has a thread with a core diameter of 2.0 to 30 mm, i.e., a standard thread or a self-tapping thread.

[0011] In a preferred embodiment, the proximal end of the material conveying screw has a shape and / or at least one recess designed for driving the material conveying screw with the drive tool.

[0012] The proximal end of the material conveying screw preferably comprises a screw head having an average diameter preferably larger than the outer diameter of the remainder of the material conveying screw, and more preferably the screw head has a shape and / or at least one recess designed for driving the material conveying screw with the driving tool.

[0013] Preferably, the length or total length of the threads of the material conveying screw, or the length of the material conveying screw excluding the screw head if present, is about 30 mm to about 100 mm, more preferably about 40 mm to about 90 mm.

[0014] In a particular embodiment of the invention, the end, or rather the end region, of the material conveying screw opposite the screw head can be tapered conically or in another shape, which is particularly preferred for self-tapping threads of the material conveying screw.

[0015] In a further preferred embodiment, the outer diameter of the thread (excluding any conically tapered or otherwise tapered ends) is about 4.0 to about 5.0 mm. In certain embodiments, the core diameter of the thread may be about 2.0 to about 4.0 mm. In a further preferred embodiment, the flank angle of the threaded screw may be about 30° to about 80°, preferably about 55° to about 65°, and most preferably about 60°. In another embodiment, the lead angle is about 2° to about 50°, and in other embodiments, about 5° to about 50°, and most preferably about 3°. In additional specific embodiments of the present invention, the pitch of the thread is about 0.4 mm to about 4.0 mm. In certain embodiments of the present invention, the thread may have a thread depth of about 0.25 mm to about 3.0 mm. In additional embodiments, the thread width of the thread may be about 0.1 mm to about 2.0 mm.

[0016] According to the present invention, the term "standard thread" means a substantially standardized thread, the parameters of which comply with national or international standards. Preferably, said standard thread is selected from metric or inch standard threads. Preferred standard threads correspond to metric ISO standard threads according to the valid, i.e. current, version of DIN 13-1, preferably DIN 13-1 (1999-11). More preferably, said threads are selected from sizes M2 to M20, in particular M2, M2.5, M3, M3.5, M4, M4.5, M5, M5.5, M6, M7, M8, M9, M10, M11, M12, M13, M14, M15, M16, M17, M18, M19, M20, according to the valid, i.e. current, version of DIN 13-1, preferably DIN 13-1 (1999-11). In another embodiment of the invention, said standard threads are inch-designated standard threads according to the respective valid, i.e. current version of ASME / ANSI B1.1, preferably ASME / ANSI-B1.1 1989 (R2003). More preferably, the threads are selected from the following sizes: #3-64 UNC, #4-40 UNC, #5-40 UNC, #6-32 UNC, #8-32 UNC, #10-24 UNC, #12-24 UNC, 1 / 4"-20 UNC, 5 / 16"-18 UNC, 3 / 8"-16 UNC, 7 / 16"-14 UNC, 1 / 2"-13 UNC, 9 / 16"-12 UNC, 5 / 8"-11 UNC, 3 / 4"-10 UNC, 7 / 8"-9 UNC, 1"-8 UNC, each in accordance with valid, i.e., current, version of ASME / ANSI B1.1, preferably ASME / ANSI-B1.1 1989 (R2003). In another embodiment of the invention, the threads can be Whitworth threads, with 1 / 4" to 3 / 4" Whitworth threads being preferred.

[0017] In the case of material-conveying screws with self-tapping threads (also called self-cutting threads), wood threads are preferably used. Wood threads suitable for use in the present invention are also standardized wood threads, more preferably metric wood threads. Metric wood threads according to the currently valid, i.e., latest edition, DIN 7988 are more preferred. Wood threads according to DIN 7988 (1975-2) are particularly preferred. In a particularly preferred embodiment, the wood threads are selected from H3 to H20, including H3, H3.5, H4, H4.5, H5, H5.5, H6, H7, H8, H10, H12, H16, and H20, according to the respective currently valid, i.e., latest edition, DIN 7988 (1975-2), most preferably DIN 7988 (1975-2).

[0018] In a preferred embodiment of the invention, the flanks of the threads of the material-conveying screw, preferably standard or self-tapping threads, are designed such that at least at or near their meeting point (i.e. at or near the meeting point of the legs of the thread flanks), and therefore at least on the outside of the thread, the flanks do not form acute angles with one another, so that at their ends, i.e. at the parts where the legs of the flanks meet or rather converge (at least in the region of the flank ends), the flanks are preferably flattened or rounded compared to an otherwise essentially identical material-conveying screw. Such an embodiment has the particular advantage that material wear and / or material loss is at least reduced and preferably essentially prevented wherever the flank ends, or rather flank ends (in particular at or near the meeting point of the legs of the flanks), are in constant contact with the feed housing typically present, or rather with the feed channel therein, which typically accommodates the material-conveying screw. This reduction, or rather prevention, of material wear preferably relates to the flank ends and / or the feed housing, or rather the feed channel housing the material-conveying screw, and more preferably to both. Reduction of material wear, or rather material loss, in this context means that material wear, or rather material loss, is reduced by preferably at least about 30%, more preferably at least about 40%, even more preferably at least about 50%, even more preferably at least about 60%, even more preferably at least about 70%, even more preferably at least about 80%, even more preferably at least about 90%, and most preferably at least about 95%, compared to a material-conveying screw that does not have flat or rounded flank ends as described above, preferably an otherwise essentially identical material-conveying screw. It will be clear to those skilled in the art that the percentage reduction in material wear and / or material loss is set in relation to a predetermined period of operation, or rather a period of use, of the respective parts subject to material wear, or rather material loss (the material-conveying screw and / or the feed housing, or rather the feed channel housing therein housing the material-conveying screw).The corresponding time may be, for example, about 10 hours, about 50 hours, about 100 hours, about 200 hours, or about 500 hours or more, and may be selected from a predetermined operating time, or rather a time of use, such as, for example, about 1000 hours. In another embodiment, the reduction in material wear and / or material loss may also be determined for objects printed with the aid of the print head, or rather the printing device, of the present invention, by analyzing the printed objects with respect to material originating from the transport screw and / or the supply housing, or rather the supply channel, with the corresponding amount of worn, or rather lost, material typically expressed in mass units such as ng, μg, mg, or grams per printed object or per multiple of printed objects, such as about 100, about 200, or about 500 or more objects, for example, about 1000 or about 2000 or more.

[0019] In preferred embodiments of this type, the flanks, or rather the flank ends, of said standard or self-tapping threads are at least approximately trapezoidal, conical or spherical, or are shaped in this way. With regard to the flanks of trapezoidal threads, it is also preferred that the (outside) corners of the trapezoidal flanks are rounded.

[0020] In a further preferred embodiment of the invention of the aforementioned kind, the standard thread of said material conveying screw (5) is selected from M5 to M20 according to DIN 158-1 (1997-06).

[0021] In relation to the above-mentioned design of the threads of the material conveying screw, in particular for reducing or preventing material wear and / or material loss at the contact points with the flanks of said threads and / or with the feed housing, or rather the channel thereof, for receiving said material conveying screw, those skilled in the art will understand that such threads are also standard, or rather self-tapping, threads, insofar as, apart from at least the rounded, or rather flattened, ends of the flanks of said threads, they otherwise correspond to conventional standard, or rather self-tapping, threads, in particular in terms of parameters according to national or international standards, and this is understood in the sense of the term "standard, or rather "self-tapping, thread".

[0022] The above-mentioned reduction or indeed substantial prevention of material wear, or rather material loss, is particularly important in relation to the use of the print head and / or printing apparatus and / or kit according to the invention for the additive manufacturing of pharmaceutical, nutraceutical and / or food supplement products, in particular dosage forms, more preferably oral dosage forms, preferably by the additive manufacturing method according to the invention, since such objects are administered to a user, contamination by such material wear and / or material loss should by the invention at least be reduced or prevented as far as possible in such objects.

[0023] According to the present invention, it is preferable to use a standard screw as the material transport screw, preferably having a thread as described in the previous paragraph, as this screw combines particularly high availability with cost-effectiveness in the manufacture and maintenance of such a printhead. Such screws are widely available in large quantities, even at DIY stores. In the field of additive manufacturing of pharmaceutical, nutraceutical, and / or food supplement products, particularly dosage forms, more preferably oral dosage forms, the entire screw in question, at least the part that comes into contact with the printing material, i.e., typically the threaded part of the material transport screw, should be made entirely of high-quality steel that may be required for the manufacturing approval of pharmaceutical, nutraceutical, and / or food supplement products. Examples of materials that can be used for the above-mentioned applications are high-quality steels such as V2A and V4A, particularly preferably steels of steel group numbers 1.43, 1.44, and 1.45 according to the respective valid, i.e., current, versions of DIN EN 10027-1 / 10027-2.

[0024] When the proximal end of the material conveying screw has a screw head, the shape of the head of the material conveying screw is preferably selected from a lens head, a plate head, a countersunk head (including a lens countersunk head, a milled countersunk head, and a trumpet head), a hexagonal head, a round head (sometimes called a semi-round head), a pan head, and a cylindrical head.

[0025] The choice of material transport screw, particularly the shape and thread selection, is determined by the type and size of the printing material being used, such as pellets, granules, or powder.

[0026] In a preferred embodiment, the drive geometry, i.e., the way in which the proximal end of the material-conveying screw, preferably the screw head, is shaped so that the drive element of the drive tool can engage by a form fit within the screw head (specifically, by means of a suitable recess in the screw head) rather than on the screw head (specifically, by means of the external shape of the screw head), rather than by a drive type fit, is selected from external hexagonal drive, internal hexagonal drive, slot drive, cross slot drive, Pozidriv drive, internal hexalobular (also known as Torx) drive, external hexalobular drive, MORTORQ® drive, TORX PLUS® drive, LocTec® drive, and Seclock drive. Particularly preferred drives are Torx drives or Torx Plus drives, rather than internal hexalobular drives. In another embodiment of a material conveying screw that can be used in accordance with the present invention but does not have a screw head, the proximal end of the screw also has a drive section designed to engage the drive tool with one or more recesses in or at the proximal end of the material conveying screw by a form fit, rather than a drive-type fit, or the shape of the proximal end (or rather the correspondingly designed proximal end region of the material conveying screw) is configured to engage the drive tool with the proximal end, or rather the proximal end region of the material conveying screw by a form fit, rather than a drive-type fit, and the drive type is preferably selected from external hexagonal drive, internal hexagonal drive, slot drive, cross slot drive, Pozidriv drive, internal hexalobular (also called Torx) drive, external hexalobular drive, Motorq drive, Torx Plus drive, Locktec drive, and Sec-Lock drive. Particularly preferred drives are Torx drives or Torx Plus drives, rather than internal hexalobular drives.

[0027] The drive device of the print head according to the present invention preferably has a drive element that engages at or rather in the proximal end of the material transport screw by a form-fit or rather by a drive system fit, preferably at or rather in the screw head. The drive element is detachably connected to the drive device, more preferably via an exchange mechanism. Such an embodiment can be realized, for example, by so-called bits that are detachably fixed in corresponding receptacles of the drive device. Typically, such bits are held in the receptacles by spring elements. In another embodiment, the exchange mechanism can also be provided by a clamping device such as a drill chuck.

[0028] The print head according to the present invention preferably also comprises means for receiving the particulate printing material, preferably pellets, granules or powder, before feeding it to the material supply device, preferably an arrangement or mechanism for taking in, rather than feeding, the printing material to the material supply device. Typically, a funnel-shaped embodiment with an appropriate opening and closing mechanism can be used in certain embodiments. In other embodiments, even in the case of a material container, a conveying screw or a conveying auger can be used to feed the printing material to the material supply device.

[0029] The print head according to the present invention, in this example an extrusion print head, comprises additional components, such as a print nozzle (also called an extrusion nozzle), commonly used in additive manufacturing processes, which in the context of the present invention are preferably characterized as FDM (filament deposition modeling) processes. Another common component is a heating fixture, preferably located upstream of the print nozzle, for heating the typically solid or semi-solid printing material into an extrudable form. In preferred embodiments, the print head may also have a cooling mechanism, such as cooling fins, to dissipate, or rather, regulate, the generated heat. A coolant may also circulate within the cooling fixture that may be used in accordance with the present invention.

[0030] The drive tool typically comprises a motor, which in certain embodiments can be designed as a stepper motor. In other embodiments, the motor can generate continuous motion. In either case, the drive tool ensures rotational motion, which is transmitted to the material feed screw via a drive element. The drive tool is preferably designed to drive the material feed screw about its longitudinal axis at about 2 to about 20 revolutions per minute (rpm), more preferably about 2 to about 12 revolutions per minute.

[0031] In an additional aspect, the present invention provides a method for producing a pharmaceutical composition comprising: - at least one print head (1) for an additive manufacturing process, comprising a print nozzle (2), a material supply device configured to receive at least one material transport screw (5), and a drive device (9) for said at least one material transport screw (5), - at least one material conveying screw (5) configured to move particulate printing material into the print nozzle (2) by rotational movement about its longitudinal axis when the material conveying screw is disposed in the material supply device, wherein when the at least one material conveying screw is disposed in the material supply device, a proximal end of the at least one material conveying screw is driven by the drive device and a distal end of the at least one material conveying screw conveys the printing material into the print nozzle (2); At least one of the material conveying screws (5) has a standard or self-tapping thread at least in the portion including the distal end of the material conveying screw.

[0032] The additional kit of the present invention comprises the specified print head having a material transport screw arranged therein and at least one additional material transport screw as specified in the present invention, wherein the one or more additional material transport screws may be the same or different, and this applies to each other as well as to the material transport screws already arranged in the print head of the present invention.

[0033] Therefore, the print head according to the present invention can also be provided as a kit (also called a "goods") together with one or more material transport screws and / or together with one or more drive elements, preferably in the form of bits adapted to the drive method of the one or more material transport screws and which can be removably connected to the drive device, preferably via an exchange mechanism.

[0034] The kit may include screws having the same or different threads and / or lengths and / or screw heads and / or drive schemes. Optionally, the kit may include the same or different drive elements adapted to one or more of the drive schemes of one or more of the material conveying screws.

[0035] As already explained above, the kit according to the invention can be designed so that at least one print head already comprises a material conveying screw arranged therein. Alternatively, as defined in more detail above, said kit comprises at least one print head as described above without a material conveying screw arranged therein and at least one material conveying screw as described above, said kit of this kind also comprising one or more drive elements adapted to the drive manner of said one or more material conveying screws, said drive element(s), preferably in the form of bits, being detachably connectable to said drive tool, preferably by means of an exchange mechanism.

[0036] Preferred embodiments of the one or more material conveying screws of the kit according to the invention are as described above.

[0037] The present invention also relates to a printing apparatus for additive manufacturing processes comprising one or more printheads of the present invention and a print bed comprising a print table having a printing surface.

[0038] Preferably, the printing apparatus further comprises conventional elements and implements typical and / or useful for 2D and / or 3D printing apparatus, in particular at least one of the print heads and / or the print table is typically movable by suitable, typically electric, servo motors, so that the position of one or more of the print heads, or rather at least one of the print nozzles, can be changed relative to the printing surface in the spatial axes x, y and z.

[0039] In a preferred embodiment of the invention, the printing device comprises a unit for calibrating, preferably automatically, the position of one or more of the print nozzles, in particular an optical device for taking an image of one or more of the print nozzles of the printing device. In this respect, reference is made to the disclosure of German Utility Model Publication No. 20 2021 003 596 U1.

[0040] The printing device preferably comprises a computer-aided control unit designed to move and detect the position of the printing table and / or at least the print nozzles of the print head, or rather each print nozzle of a plurality of said print heads.

[0041] Additionally, the printing device preferably includes a computer-aided image processing unit designed to display and process image data of one or more of the print nozzles generated by the optical instrument.

[0042] It is also preferred that the printing device comprises a calculator configured to correlate image data from the computer-aided image processing unit with position data from the computer-aided control unit, specifically, the calculator configured to measure and store differences in at least x and y position data (i.e., horizontal position data), and preferably also z position data (i.e., vertical position data).

[0043] In a preferred embodiment of the invention, the printing device comprises at least one tool for analyzing the additive manufacturing processes performed therewith, in particular 2D printing and / or 3D printing, and / or the objects produced with the printing device.

[0044] The printing device preferably comprises at least one instrument for spectroscopic measurement of the material applied to the printing surface. In a particularly preferred embodiment, this instrument is an instrument for infrared spectroscopy, more preferably a NIR (near infrared) instrument. In another embodiment, a Raman spectrometer is used, and Raman spectroscopy and infrared spectroscopy (more preferably NIR spectroscopy) can be used simultaneously or sequentially, in which case the instrument according to the invention comprises both an instrument for Raman spectroscopy and an instrument for infrared spectroscopy, more preferably NIR spectroscopy.

[0045] In a further embodiment of the invention, one or more of the print heads each comprise an instrument for measuring the flow rate of material entering the print head and / or passing through the print head, or rather through the print nozzles. In a preferred embodiment, the flow rate is measured using a magnetic inductive flow meter. In accordance with the invention, the instrument for measuring flow rate is preferably used in a printing apparatus of the invention, which is specifically designed for 2D printing or at least for 2D printing.

[0046] In an additional embodiment, the printing device includes a device, preferably an infrared camera, for recording thermal images of material emerging from one or more of the print nozzles and / or material applied to the print surface.

[0047] Additionally, one or more of the printheads may be equipped with instrumentation for inductive flow measurement.

[0048] In an additional preferred embodiment, the print table includes a metering device.

[0049] The printing apparatus according to the present invention preferably comprises a preferably computer-aided device for recording, handling and monitoring the process data collected with the aid of the above-mentioned process analysis instrument, which device is also referred to as process monitoring device hereinafter, and which is further preferably connected to the above-mentioned computer-aided control unit, computer-aided image processing unit and computing unit, preferably via a data exchange device and / or a data transfer device and / or a data receiving device, so as to be able to integrate the process parameters obtained via one or more of the above-mentioned process monitoring devices.

[0050] According to the invention, the method according to the invention is typically implemented in a computerized or rather computer-aided form, particularly preferably using a computer-aided control unit and / or a computer-aided image processing unit and / or a computing unit as already described above.

[0051] Also disclosed is an additive manufacturing method, preferably for 2D printing and / or 3D printing, for producing an object, preferably an active ingredient-containing object, preferably a pharmaceutical and / or nutraceutical and / or food supplement dosage form, preferably a dosage form for oral administration, comprising the step of printing a particulate printing material such as pellets, granules and / or powder using the printing apparatus according to the present invention.

[0052] Furthermore, the printing method is preferably performed using one or more of the aforementioned instruments for analyzing the build process.

[0053] Also disclosed is a method for producing a particulate printing material, preferably pelleted, granular or powdered printing material, which in a preferred embodiment can be carried out prior to said additive manufacturing method, said printing material preferably comprising at least one pharmaceutical active ingredient and / or at least one nutraceutical active ingredient and / or at least one food supplement active ingredient, typically in at least one pharmaceutically acceptable carrier and / or nutraceutically acceptable carrier and / or food supplement compatible carrier.

[0054] The method for producing particulate print material comprises: (a) generating a filamentary printed blank; (b) shredding the print blank.

[0055] In a preferred embodiment, the filament-like printing blank, also referred to herein as a printing material filament, is suitably produced from a starting material, or rather a starting material, by extrusion, preferably hot melt extrusion (HME). The particle size of the resulting printing material can be determined at least in two dimensions by selecting the diameter of the filament. The chopping can be performed, for example, by cutting the blank. Of course, any mechanical or other comminution process can be selected and combined with each other. This process can also include a size selection step, or rather a sorting step. For example, the material obtained after chopping can be sorted according to the corresponding particle size. In a preferred embodiment, chopping and sorting can be performed simultaneously, for example, through a rasp screen process using commonly available commercially available equipment. [Brief explanation of the drawings]

[0056] The invention will be explained in more detail below in exemplary, non-limiting embodiments with reference to the accompanying drawings, in which: [Figure 1]1 is a schematic diagram of a front view of a print head according to the present invention. The relevant components of the print head (1) are described below with reference to FIG. 1 from the bottom (also referred to in this disclosure as "distal," in relation to the end of the material-conveying screw connected to the drive tool) to the top (also referred to in this disclosure as "proximal," in relation to the end of the material-conveying screw connected to the drive tool). The print head 1 of this embodiment has a print nozzle 2. Particulate printing material, preferably pellets, granules, or powder, is heated by a heating device 3 to convert the printing material into a flowable state. To prevent overheating of the system, the print head 1 includes a cooling device 4, preferably including cooling fins through which a coolant flows, as described in this embodiment with reference to FIG. 1. A supply chamber 10, which partially conceals the screw 5 in this view, is provided above the cooling device 4, where the printing material is supplied to the screw chamber (also referred to as the transport chamber or extrusion chamber). This supply can be achieved, for example, via a funnel-like configuration, typically equipped with an opening and closing mechanism. The material conveying screw 5 extends above the feed chamber 10, which may also serve as a guide element for the screw 5, and is supported directly below the screw head in a screw holder 6, in which the screw 5 is centrally located directly below the screw head 5a, which in this case is a countersunk head, and is mounted rotatably about its longitudinal axis. [Figure 2]The essential elements of the print head 1 according to the present invention are shown in a schematic cross-sectional side view, without the usual housing, for clarity. From bottom (distal) to top (proximal), the cross-sectional view shows the heating device 3 adjacent to the print nozzle. The distal end, or rather the distal end region, of the material transport screw 5 tapers conically and terminates in the heating device 3. The material transport screw 5 extends within a transport chamber (also called an extrusion chamber), which begins directly above the heating device and extends to its tip (here, to its apex) into the supply chamber 10. Above (proximally), the supply chamber 10 continues, into which the printing material, preferably pellets, granules, and / or powder, is supplied via a dispensing device 7a. The screw 5 extends further upward (proximally) through the supply chamber 10 and is mounted in the upper (proximal) region of the holder 6, rotatably about its longitudinal axis and centrally located. In this embodiment, the retaining portion 6 surrounds part of the thread and part of the (countersunk) screw head 5a. In the illustrated embodiment, the dispensing fixture 7a, the supply chamber 10, the screw retaining portion 6 and substantially the upper (proximal) part of the transport chamber (i.e., behind the cooling fixture in the proximal direction) are arranged within the supply housing 7. The material transport screw 5 is provided with a self-tapping thread, except for the screw head 5a. [Figure 3] 2 is a schematic view of the individual components of a print head according to the present invention, in which the material transport screw 5 with the countersunk Torx head 5a and the drive element with the Torx screw drive 8a have not yet been inserted into the supply housing 7, in which the dispensing fixture 7a, the supply chamber 10, the screw holder 6 and the approximate upper (proximal) part of the transport chamber (i.e., behind the cooling fixture in the proximal direction) are arranged as described above with reference to FIG. 2. The drive element 8 with the screw drive 8a is designed as a bit that allows for a quick exchange of drive systems and screw types. [Figure 4] 4 is a further schematic view of the elements of FIG. 3, in which a drive element 8 with a Torx drive 8a is inserted into a drive tool 9. FIG. [Figure 5]1 is a schematic view of a material conveying screw 5 inserted into a conveying chamber in a supply housing 7. FIG. [Figure 6] 1 shows an additional schematic view of the elements of the print head in the assembled state, in particular how the Torx drive part 8a of the drive element 8 engages with a corresponding Torx recess in the countersunk head 5a of the material transport screw 5 by form-fitting. [Figure 7A] 7A and 7B show a metoprolol succinate oral dosage form printed using an embodiment of the present invention, in this case a biplanar object in the form of a tablet. Figure 7A shows a top view of the printed tablet. [Figure 7B] 7A and 7B show a metoprolol succinate oral dosage form printed using an embodiment of the present invention, in this case a biplanar object in the form of a tablet. FIG. 7B is a side view of the printed tablet. DETAILED DESCRIPTION OF THE INVENTION

[0057] The present invention will now be further described with reference to the following non-limiting examples.

[0058] (Example) Using a printing device according to the present invention, two different metoprolol succinate formulations (A and B) were printed by FDM in tablet form.

[0059] Both formulations were first prepared from powdered raw materials by geometric three-stage tumble mixing. Hot-melt extrusion was then performed using a laboratory extruder (ZE HM99, Three Tec GmbH, Sion, Switzerland) with a 2 mm die diameter. The extrusion temperature was 100°C for Formulation A and 140°C for Formulation B. The extruded strands were chopped by rasp sieving using a U5 Comil® tool (Quadro Engineering Corp., Waterloo, Canada) at 250 rpm to obtain granules with a particle size of 1-2 mm.

[0060] Table 1 below shows the ingredients of Formulations A and B and their proportions (in weight percent based on the total weight of each formulation). [Table 1] MSN: Metoprolol succinate (active pharmaceutical ingredient) KVA64: Kollidon VA64 (vinylpyrrolidone-vinyl acetate copolymer; carrier polymer) EPO: Eudragit EPO (anionic copolymer of methacrylic acid and methyl methacrylate; carrier polymer) PEG: Lyxopol 6000 (polyethylene glycol; plasticizer).

[0061] The parameters of the extrusion screw (material conveying screw) used were varied as shown in Table 2 below. This screw is capable of processing both granules and powders. [Table 2]

[0062] From the resulting granules, tablets were printed by FDM using the print head of the present invention as a component of the printing device of the present invention. The print throughput (print volume per unit time) at the print nozzle was 1.131 mm 3 The printing temperature was varied between 140°C and 160°C, and the printing surface temperature of the printing table was 50°C. Typical dosage forms obtained by the printing process are shown in Figure 7A (top view) and Figure 7B (side view). [Explanation of symbols]

[0063] 1 print head 2 print nozzles 3 Heating equipment 4 Cooling equipment 5 Material conveying screw 5a Head 6 Screw holding part 7 Supply housing 7a Dispensing equipment 8 Driving Elements 8a Screw drive unit 9 Driving equipment 10 Supply room

Claims

1. 1. A print head for an additive manufacturing process, the print head comprising: - a print nozzle (2), a material supplying device; The material supply device comprises: (i) at least one material conveying screw (5) configured to supply particulate printing material into the printing nozzle (2) by a rotational movement about a longitudinal axis; and (ii) at least one drive device (9) for the at least one material conveying screw (5), a proximal end of at least one of the material conveying screws is driven by the driving device, and a distal end of the material conveying screw conveys the printing material into the printing nozzle; At least one of the material conveying screws (5) has a standard or self-tapping thread at least in a portion including a distal end of the at least one material conveying screw. A print head characterized by:

2. The thread of the material conveying screw (5) has a core diameter of 2.0 to 30 mm.

2. The printhead of claim 1.

3. The proximal end of the material conveying screw (5) has a shape and / or at least one recess designed for driving the material conveying screw (5) with the driving tool (9).

3. A printhead according to claim 1 or 2, characterized in that:

4. The length of the thread of the material conveying screw (5) is 30 mm to 100 mm.

4. A printhead according to claim 1, wherein the printhead comprises:

5. The standard thread of the material conveying screw (5) is selected from M2 to M20 according to DIN 13-1 (1999-11).

5. A printhead according to claim 1, wherein the printhead comprises:

6. The self-tapping thread is a wood thread 5. A printhead according to claim 1, wherein the printhead comprises:

7. The wood thread of the material conveying screw is selected from H3 to H20 according to DIN 7988 (1975-2).

7. The printhead of claim 6.

8. The flanks of the standard or self-tapping threads of the material-conveying screw (5) are at least approximately trapezoidal, conical or spherical.

8. A printhead according to claim 1, wherein the printhead comprises:

9. The standard thread of the material conveying screw (5) is selected from M5 to M20 according to DIN 158-1 (1997-06).

5. A printhead according to claim 1, wherein the printhead comprises:

10. The proximal end of the material conveying screw (5) comprises a screw head (5a) having a shape and / or at least one recess adapted to drive the material conveying screw (5) with the driving tool.

10. A printhead according to any one of claims 1 to 9.

11. The shape of the screw head (5a) is selected from a lens head, a plate head, a countersunk head, a square head, a hexagonal head, a round head, a pan head, and a cylindrical head.

11. The printhead of claim 10.

12. The proximal end of the material conveying screw (5), preferably the screw head (5a), has a drive system selected from external square drive, internal square drive, external hexagon drive, internal hexagon drive, slot drive, cross slot drive, Pozidriv drive, internal hexalobular drive, external hexalobular drive, MORTORQ® drive, TORX PLUS® drive, LocTec® drive, and Seclock drive.

12. A printhead according to any one of claims 1 to 11, characterized in that

13. The driving tool (9) comprises a driving element (8) which engages with the proximal end of the material conveying screw (5) by form-fitting, and preferably with the screw head (5a).

13. A printhead according to any one of claims 1 to 12.

14. The driving element (8) is detachably connected to the driving tool (9).

14. The printhead of claim 13.

15. The drive element (8) is detachably connected to the drive tool (9) via an exchange mechanism.

15. The printhead of claim 14.

16. The driving element (8) is designed as a bit, and the driving tool has a recess that receives the bit by form-fitting.

16. The printhead of claim 15.

17. 1. A printing apparatus for an additive manufacturing process, comprising: one or more printheads (1) according to any one of claims 1 to 16, a print bed comprising a print table having a print surface; 1. A printing apparatus for additive manufacturing processes, comprising:

18. at least one print head (1) for an additive manufacturing process, comprising a print nozzle (2), a material supply device configured to receive at least one material conveying screw (5), and a drive device (9) for said material conveying screw (5); at least one material conveying screw (5) configured to move particulate printing material into said printing nozzle (2) by a rotational movement about its longitudinal axis when said material conveying screw (5) is arranged in said material supplying device, When the material conveying screw is disposed in the material supplying device, the proximal end of the material conveying screw (5) is driven by the driving device, and the printing material is conveyed from the distal end into the printing nozzle (2); The material conveying screw (5) has at least a standard or self-tapping thread at the distal end. A kit characterized by:

19. at least one printhead (1) according to any one of claims 1 to 16, at least one additional material conveying screw (5) configured to move particulate printing material into said printing nozzle (2) by a rotational movement about its longitudinal axis when it is arranged in said material supply device, When the material conveying screw is disposed in the material supplying device (9), the proximal end of the material conveying screw (5) is driven by the driving device, and the printing material is conveyed from the distal end into the printing nozzle (2); The additional material conveying screw (5) has at least a standard or self-tapping thread at the distal end. A kit characterized by:

20. One or more of the material conveying screws is a material conveying screw according to any one of claims 2 to 12.

20. The kit according to claim 18 or 19, characterized in that

21. 1. An additive manufacturing method for producing an object, preferably for 2D printing and / or 3D printing, said method comprising:

18. Using the printing device of claim 17 to print particulate printing material, preferably pellets, granules and / or powder. An additive manufacturing method characterized by:

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