Printing device for additive manufacturing processes with screw device for material feed

Abstract

The present invention relates to a print head for additive manufacturing processes, the print head comprising a material feeding device having a material transport screw which is designed or configured, respectively, in such a way that the screw and its drive can be inserted and changed flexibly and cost-effectively. The invention also relates to a printing device for additive manufacturing processes, which comprises at least one print head according to the invention.

Description

[0001] Printing device for additive manufacturing processes with screw device for material feeding

[0002] The present invention relates to a print head for additive manufacturing processes, which comprises a material feed device with a material transport screw, which is designed or configured such that the screw and its drive can be used and replaced flexibly and cost-effectively. The invention also relates to a printing device for additive manufacturing processes, which comprises at least one print head according to the invention.

[0003] Print heads and corresponding printing devices for additive manufacturing processes using particulate starting materials are known in the art.

[0004] Such printheads typically comprise a print nozzle and a device for feeding material into the print nozzle, typically with an extruder screw (also referred to herein as a "material transport screw"). Examples of disclosures include US 2017 / 0008230 A1 and the review article on pellet extruders by Shaik et al. (2021) in Open Access Library Journal 8: e7698.

[0005] In additive manufacturing processes such as 2D and 3D printing, which generally involve computer-controlled positioning of the printing material on a printing table of the printing device, one challenge, particularly in the area of ​​printing objects containing active ingredients in the pharmaceutical and / or dietary supplement sectors, is that printing devices intended for the realization of an individualized active ingredient supply should be as simple to construct and cost-effective to operate as possible.

[0006] The object of the invention is to provide a print head and a printing device for additive manufacturing processes that can be manufactured cost-effectively with regard to material supply and ensures a simple and variable supply of spare parts. The above object is achieved by the subject matter of the present invention disclosed in the claims, as well as in the present description and the accompanying drawings.

[0007] In particular, according to the invention, a print head for additive manufacturing processes is provided, which has a print nozzle and a material feed device with (i) at least one material transport screw, which is designed to move particulate printing material into the print nozzle by rotation about its longitudinal axis, and (ii) at least one drive device for the at least one material transport screw, wherein the at least one material transport screw has a proximal end, which is driven by the drive device, and a distal end, from which the printing material is transported into the print nozzle, and wherein the at least one material transport screw (5) has a standard thread or a self-tapping thread at least on a section which includes the distal end of the at least one material screw.

[0008] The print head according to the invention can comprise more than one print nozzle and more than one material feed device, each with one of the material transport screws defined according to the invention and the drive device for the latter.

[0009] The print head and the other objects of the invention are preferably designed for additive manufacturing by hot melt extrusion (HMT), more preferably by FDM (Filament Deposition Modeling). Particularly preferably, the print head according to the invention and the other objects of the invention are designed for additive manufacturing, preferably by FDM, of pharmaceutical, nutraceutical, and / or dietary supplement products, in particular dosage forms, more preferably oral dosage forms.

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

[0011] In preferred embodiments, the proximal end of the material transport screw has a shape and / or at least one recess designed to drive the material transport screw by the drive device. The proximal end of the material transport screw preferably has a screw head, the average diameter of which is preferably larger than the outer diameter of the other parts of the material transport screw. More preferably, the screw head has a shape and / or at least one recess designed to drive the material transport screw by the drive device.

[0012] Preferably, the length of the thread or the total length of the material transport screw or the length of the material transport screw without the screw head, if present, is about 30 mm to about 100 mm, more preferably about 40 mm to about 90 mm.

[0013] In certain embodiments of the invention, the end or end region of the material transport screw opposite the screw head can be conical or otherwise tapered. This is particularly preferred for self-tapping material transport screw threads.

[0014] In further preferred embodiments, the outer diameter of the screw thread (excluding any conical or otherwise tapered end region that may be present) is about 4.0 to about 5.0 mm. In certain embodiments, the core diameter of the screw thread can be about 2.0 to about 4.0 mm. In further preferred embodiments, the flank angle of the threaded screw can be about 30° to about 80°, preferably about 55° to about 65°, most preferably about 60°. In further embodiments, the pitch angle is about 2 to about 50°, in other embodiments about 5° to about 50°, most preferably about 3°. In further specific embodiments of the invention, the pitch of the screw thread can be about 0.4 mm to about 4.0 mm. In certain embodiments of the invention, the screw thread can have a thread depth of about 0.25 mm to about 3.0 mm.In further embodiments, the helical pitch of the screw thread may be about 0.1 mm to about 2.0 mm.

[0015] According to the invention, the term “standard thread” means a substantially standardized thread whose parameters are subject to a national or international standard. The standard thread is preferably selected from metric or inch standard threads. Preferred standard threads correspond to the metric ISO standard thread according to the valid, i.e. current, version of DIN 13-1, preferably DIN 13-1 (1999-11). More preferably, the thread is selected from sizes M2 to M20, in particular from 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 DIN 13-1 in the valid, i.e. current version, preferably DIN 13-1 (1999-11). In other embodiments of the invention, the standard thread is an inch standard thread according to ASME / ANSI B1.1 in the currently valid version, preferably according to ASME / ANSI-B1.1 1989 (R2003).More preferably, the thread is selected from the 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 according to ASME / ANSI B1.1 in the currently valid version, preferably according to ASME / ANSI-B1.1 1989 (R2003). In other embodiments of the invention, the thread may also be a Whitworth thread, with 1 / 4" to 3 / 4" Whitworth threads being preferred.

[0016] In the case of a material transport screw with a self-forming thread (also referred to as a self-tapping thread), wood screw threads are preferably used. Preferred wood screw threads for use in the present invention are also standardized wood screw threads, particularly preferably metric wood screw threads. More preferred are metric wood screw threads according to DIN 7988 in the currently valid, i.e. most recent, version. Very particular preference is given to wood screw threads according to DIN 7988 (1975-2). In particularly preferred embodiments, the wood screw thread is selected from H3 to H20, including H3, H3.5, H4, H4.5, H5, H5.5, H6, H7, H8, H10, H12, H16, H20, according to DIN 7988 in the currently valid, i.e. most recent, version, very particularly preferably DIN 7988 (1975-2).

[0017] In preferred embodiments of the invention, the flanks of the thread, preferably of the standard thread or the self-tapping thread of the material transport screw, are designed in such a way that the flanks do not have an acute angle to one another, at least at or in the vicinity of their meeting point (i.e. the meeting point of the legs of the thread flanks or in the vicinity thereof), i.e. at least on the outer side of the thread, and thus the flanks are preferably flattened and / or rounded at their ends, i.e. where the legs of the flank meet or converge, at least in the region of the flank ends, compared to an otherwise essentially identical material transport screw. Such embodiments have the particular advantage that material abrasion and / or loss at the ends of the flanks orwhere there is a certain contact of the flank ends (in particular at or near the meeting point of the leg flanks) with the usually present feed housing or in the feed channel that usually accommodates the material transport screw therein, this contact is at least reduced, preferably substantially avoided. The reduction or avoidance of material abrasion preferably relates to the flank ends and / or the feed housing or the feed channel that accommodates the material transport screw, more preferably both. A reduction in material abrasion or loss in this context means that the material abrasion orMaterial loss is preferably reduced by at least about 30%, more preferably by at least about 40%, further preferably by at least about 50%, even more preferably by at least about 60%, furthermore preferably by at least about 70%, still more preferably by at least about 80%, furthermore even more preferably by at least about 90%, most preferably by at least about 95% in comparison to a material transport screw, preferably an otherwise essentially identical material transport screw which does not have flattened and / or rounded flank ends as described above. It is apparent to a person skilled in the art that the percentage reduction in material abrasion and / or loss is set in relation to a specified operating or usage period of the respective unit (material transport screw and / or feed housing or feed channel located therein which accommodates the material transport screw), which corresponds to the material abrasion oris subject to material loss. Corresponding time periods can, for example, be selected from a fixed number of operating hours or hours of use, such as approximately 10 hours, approximately 50 hours, approximately 100 hours, approximately 200 hours, or approximately 500 hours or more, such as approximately 1000 hours. In another embodiment, the reduction in material abrasion and / or material loss can also be determined in relation to any object present in an object produced using the print head or printing device according to the invention, by analyzing printed objects for material present from the transport screw and / or the feed housing or the feed channel, wherein corresponding amounts of the abrasion or loss material are usually measured in mass units such as ng, pg, mg, or grams per printed object or a multiplicity of printed objects, such as approximately 100, approximately 200, approximately 500 or more objects, such as, for example,about 1000 or about 2000 objects or more.

[0018] In preferred embodiments of this type, the flanks or flank ends of the standard thread or the self-tapping thread are at least approximately trapezoidal, conical, or spherical, or are configured in such a manner. With regard to trapezoidal thread flanks, it is further preferred that the corners of the trapezoidal flank (on the outside) are rounded. In further preferred embodiments of the invention of the aforementioned type, the standard thread of the material transport screw (5) is selected from M5 to M20 according to DIN 158-1 (1997-06).

[0019] In connection with the above-described design of the material transport screw thread to reduce or prevent material abrasion and / or loss, in particular on the flanks of the thread and / or at the contact points with the feed housing or its channel for receiving the material transport screw, the person skilled in the art understands, or in this sense the term standard thread or self-forming thread is understood, that such threads are also standard or self-forming threads, at least insofar as these threads, with the exception of the rounded or flattened ends of the thread flanks, otherwise correspond to a conventional standard thread or self-forming thread, in particular with regard to the parameters according to a national or international standard.

[0020] The reduction or even substantial prevention of material abrasion or loss described above is particularly important with regard to the use of print heads and / or printing devices and / or kits according to the invention for the additive manufacturing of pharmaceutical, nutraceutical and / or dietary supplement products, in particular dosage forms, more preferably oral dosage forms, preferably by means of an additive printing process according to the invention, since such objects are supplied to users and contamination in such objects due to such material abrasion and / or loss is to be at least reduced or avoided as far as possible according to the invention.

[0021] According to the invention, it is preferred to use standard screws as material transport screws, preferably with a thread as described in the previous paragraph, which combines particularly high availability with a cost-effective price for the manufacture of a print head equipped in this way, as well as for its maintenance. Such screws are therefore available in large numbers and across a wide range, even in hardware stores.In the field of additive manufacturing of pharmaceutical, nutraceutical, and / or dietary supplement products, especially dosage forms, more preferably oral dosage forms, the screw should be made entirely of or comprise a high-quality steel, at least the part of the screw that comes into contact with the printing materials, i.e., typically the threaded part of the material transport screw. This steel may be required for approval for the production of pharmaceutical, nutraceutical, and / or dietary supplement products. Examples of materials suitable for these applications include high-quality steels such as V2A and V4A, particularly preferably steels of steel group numbers 1.43, 1.44, and 1.45 according to DIN EN 10027-1 / -2 in the currently valid version.

[0022] If the proximal end of the material screw has a screw head, the shape of the head of the material transport screw is preferably selected from lens head, flat head, countersunk head (including lens countersunk head, countersunk milling head and trumpet head), hexagon, round head (sometimes also referred to as half-round head), pan head and cylinder head.

[0023] The choice of material transport screw, especially in terms of shape and thread, will depend on the type and size of the printing material to be used, such as pellets, granules or powder.

[0024] The drive type, i.e. the way in which the proximal end of the material screw, preferably the screw head, is shaped so that the drive element of the drive device can engage or act in a form-fitting or driving manner in the screw head (in particular by means of suitable recesses in the screw head) or on the screw head (in particular by means of the external shape of the screw head), is selected in preferred embodiments from external hexagon, internal hexagon, slotted, Phillips, Pozidriv, internal hexalobular (also called Torx), external hexalobular, Mortorq, Torx Plus, LocTec and Secloc drives. Very particularly preferred drives are internal hexalobular or Torx or Torx Plus drives. In other embodiments of material transport screws which can be used according to the invention and which do not have a screw head, the proximal end of the screw has a drive which is likewise designed such that the drive device can engage or act in a form-fitting or driving manner.engage in a drive-locking manner in one or more recesses on or in the proximal end of the material transport screw, or the shape of the proximal end (or a correspondingly designed proximal end region of the material transport screw) is configured such that the drive device can engage the proximal end or the proximal end region of the material transport region in a form-locking or drive-locking manner. In preferred embodiments, the drive is selected from external hexagon, internal hexagon, slotted, Phillips, Pozidriv, internal hexalobular (also called Torx), external hexalobular, Mortorq, Torx-Plus, LocTec, and Secloc drives. Particularly preferred drives are internal hexalobular, Torx, or Torx-Plus drives.

[0025] The drive device of the print head according to the invention preferably has a drive element that engages or engages in a form-fitting or driving manner with the proximal end of the material transport screw, preferably with the screw head. Particularly preferably, the drive element is detachably connected to the drive device; more preferably, the drive element is detachably connected to the drive device by a change mechanism. Such embodiments can be realized, for example, by so-called bits that are detachably fastened in a corresponding receptacle of the drive device. Such bits are usually held in the receptacle by a spring element. In other embodiments, the change mechanism can also be provided by a clamping device such as a drill chuck or the like.

[0026] The print head according to the invention preferably comprises a device for receiving the particulate printing material, preferably pellets, granules, or powder, before it is fed to the material feed device, as well as preferably also a configuration or mechanism for feeding or introducing the printing material into the material feed device. Funnel-like configurations, which are usually provided with a suitable closing and opening mechanism, can be used in certain embodiments. In other embodiments, a transport screw or auger can also be used in the case of the material container to feed the printing material to the material feed device.

[0027] The print head according to the invention, in this case an extrusion print head, comprises further components generally used for additive manufacturing processes, which in the context of the invention are preferably characterized as an FDM (Filament Deposition Modeling) process, such as a print nozzle (also referred to as an extrusion nozzle). Another common component is a heating device, preferably located upstream of the print nozzle, for heating the typically solid or semi-solid printing material into an extrudable form. In a preferred embodiment, the print head can also have cooling mechanisms, such as cooling fins, to dissipate or regulate the generated heat. Coolants can also circulate in cooling devices usable according to the invention.

[0028] The drive device typically comprises a motor, which in certain embodiments can be configured as a stepper motor. In other embodiments, the motor can also generate a continuous movement. In any case, the drive device provides a rotary movement, which is transmitted to the material transport screw via a drive element. The drive unit is preferably configured to drive the material transport screw at approximately 2 to approximately 20, more preferably approximately 2 to approximately 12, revolutions per minute (rpm) around its longitudinal axis.

[0029] From a further aspect, the invention provides a kit or article comprising at least one print head (1) for additive manufacturing processes, a print nozzle (2) and a material feed device designed to receive at least one material transport screw (5), and comprising a drive device (9) for the at least one material transport screw (5), and at least one material transport screw (5) designed to move particulate printing material into the print nozzle (2) by rotation about its longitudinal axis when the material transport screw is arranged in the material feed device, wherein the at least one material transport screw has a proximal end driven by the drive device and a distal end from which the printing material is transported into the print nozzle (2) when the at least one material transport screw is arranged in the material feed device,wherein the at least one material transport screw (5) has a standard thread or a self-tapping thread at least on a section including the distal end of the material screw.

[0030] Another kit of the invention contains the print head as defined with the material transport screw arranged therein, and at least one further material transport screw as defined according to the invention, wherein the further material transport screw(s) may be the same or different, which applies to each other as well as to the material transport screw which is already arranged in the print head according to the invention.

[0031] The print head according to the invention can thus also be provided as a kit (also referred to as an “article”) together with one or more material transport screws and / or together with one or more drive elements, preferably adapted to the drive of the material transport screw(s), which can be detachably connected to the drive device, preferably by means of a change mechanism, preferably in the form of bits.

[0032] The kit may include screws with identical or different threads, and / or lengths, and / or screw heads, and / or drives. If necessary, the kit may include identical or different drive elements adapted to the drive(s) of the material transport screw(s).

[0033] As already explained above, kits according to the invention can be designed such that the at least one print head is already provided with a material screw arranged therein. In another embodiment, as defined in more detail above, the kit contains at least one print head as described here without a material transport screw arranged therein and at least one material transport screw as described above. This form of the kit also comprises one or more drive elements adapted to drive the material transport screw(s), which can be detachably connected to the drive device, preferably by means of a change mechanism, preferably in bit form.

[0034] Preferred embodiments of the material transport screw(s) of the kits according to the invention are as set out above.

[0035] The invention also relates to a printing device for additive manufacturing processes, comprising one or more print heads of the invention and a print bed comprising a print table with a print surface.

[0036] The printing device preferably also comprises other conventional elements and devices that are typical and / or advantageous for 2D and / or 3D printing devices. In particular, the at least one print head and / or the print table are typically movable via suitable, usually electric, servomotors, so that the position of the print head (or print heads) or at least the print nozzle (or nozzles) relative to the printing surface can be changed along the spatial axes x, y, and z.

[0037] In a preferred embodiment of the invention, the printing device comprises a device for preferably automatic position calibration of the printing nozzle(s), which in particular comprises an optical device for accommodating the printing nozzle(s) of the printing device. In this regard, reference is made to the disclosure of document DE 20 2021 003 596 U1.

[0038] The printing device preferably comprises a computer-aided control device designed to move and detect the position of the printing table and / or at least the printing nozzle of the print head(s). Furthermore, the printing device preferably comprises a computer-aided image processing device designed to display and process the image data of the printing nozzle(s) generated by the optical device.

[0039] It is also preferred that the printing device comprises a computer unit designed to correlate the image data from the computer-assisted image processing device and the position data from the computer-assisted control device. In particular, the computer unit is designed to measure and store differences in position data at least in the xy direction (i.e., horizontal position data), and preferably also in the z direction (i.e., vertical position data).

[0040] In preferred embodiments of the invention, the printing device has at least one device for analyzing the additive manufacturing process carried out with the printing device, in particular 2D and / or 3D printing, and / or the object manufactured with the aid of the device.

[0041] The printing device preferably has at least one device for spectroscopically measuring material applied to the printing surface. In particularly preferred embodiments, this device is a device for infrared spectroscopic measurement, more preferably an NIR (near-infrared) device. In other embodiments, a Raman spectroscopic device is used, whereby Raman spectroscopy and infrared spectroscopy (more preferably NIR spectroscopy) can be used simultaneously or sequentially; thus, the device according to the invention comprises both a device for Raman spectroscopy and a device for infrared spectroscopy, more preferably for NIR spectroscopy.

[0042] In a further embodiment of the invention, the print head(s) each comprise(s) a device for measuring the flow of material flowing into and / or through the print head or through the print nozzle. In preferred embodiments, the flow is measured using a magnetic-inductive flow measuring device. According to the invention, a flow measuring device is preferably used in printing devices of the invention that are designed in particular or at least also for 2D printing.

[0043] In a further embodiment, the printing device comprises a device, preferably an infrared camera, for recording a thermal image of material emerging from the printing nozzle(s) and / or of material applied to the printing surface.

[0044] Furthermore, the print head(s) may comprise a device for inductive mass pickup.

[0045] In a further preferred embodiment, the printing table comprises a weighing device.

[0046] The printing device according to the invention preferably comprises a preferably computer-assisted device for recording, handling, and monitoring the process data acquired with the aid of the aforementioned process analysis devices. This device is also referred to below as a process monitoring device. Furthermore, this preferably computer-assisted process monitoring device is preferably connected to the aforementioned computer-assisted control, image processing, and computing units via data exchange and / or data forwarding and / or data reception devices, so that the process parameters obtained via the process monitoring device(s) can be integrated.

[0047] Typically and preferably according to the invention, the method according to the invention is carried out in a computer-assisted manner, particularly preferably using the computer-assisted control and / or image processing and / or computer unit already explained above.

[0048] Also disclosed is an additive manufacturing method, preferably for 2D and / or 3D printing, for producing an object, preferably an active ingredient-containing object, preferably pharmaceutical and / or nutraceutical and / or dietary supplement dosage forms, preferably for oral administration, which comprises the step of printing a particulate printing material, such as pellets, granules and / or powder, using the printing device according to the invention.

[0049] Furthermore, the printing process is preferably carried out using one or more of the above-mentioned devices for analyzing the manufacturing process.

[0050] A method for producing a particulate printing material, preferably pellet-, granular-, or powder-form printing materials, is also disclosed, which in preferred embodiments can be applied upstream of the additive manufacturing process. The printing material preferably comprises at least one pharmaceutical and / or at least one nutraceutical and / or at least one dietary supplement active ingredient, usually in at least one pharmaceutically acceptable and / or nutraceutically acceptable and / or dietary supplement-compatible carrier.

[0051] The process for producing the particulate printing material comprises the steps

[0052] (a) producing a filament-shaped printing material blank; and

[0053] (b) Shredding the printing material blank.

[0054] In a preferred embodiment, the filament-shaped printing material blank, also referred to herein as printing material filament, is suitably produced from the starting substances or materials by extrusion, preferably hot melt extrusion (HME). The particle size of the printing material to be produced can be determined in at least two dimensions by selecting the diameter of the filament. The comminution can be carried out, for example, by cutting the blank. Of course, any mechanical or other comminution processes can be selected and combined with one another. The method can comprise a size selection or sorting step as a further step. For example, the material obtained after comminution can be sieved according to corresponding grain sizes. In preferred embodiments, the comminution and sorting can also be carried out, for example, byby rasp screening, usually using commercially available equipment.

[0055] The present invention is explained in more detail below with reference to the accompanying drawings in exemplary, non-limiting embodiments:

[0056] Fig. 1 shows a schematic representation of a front elevation of a print head according to the invention. The key components of the print head (1) are described below with reference to Figure 1 from bottom (referred to as “distal” in the present disclosure also in relation to the end of the material transport screw connected to the drive unit) to top (referred to as “proximal” in the present disclosure also in relation to the end of the material transport screw connected to the drive unit). The print head 1 of this embodiment has a print nozzle 2. The particulate printing material, preferably pellets, granules or powder, is heated by a heating device 3 in order to convert the printing material into a flowable state.To prevent the system from overheating, the print head 1 is equipped with a cooling device 4, which preferably includes cooling fins through which coolant flows, as illustrated in the present embodiment with reference to Fig. 1. Above the cooling device 4, a feed chamber 10 is provided, which in the present plan view conceals part of the screw 5, wherein in this area the printing material is fed into the screw chamber (also referred to as transport or extruder chamber), which can take place, for example, via a funnel-shaped arrangement, which is typically provided with an opener / closer mechanism.The material transport screw 5 extends above the feed chamber 10, which can also serve as a guide element for the screw 5, and is supported directly below the screw head by a screw holder 6, in which the screw 5 is centered directly below the screw head 5a, in this case a countersunk head, and is rotatably mounted about its longitudinal axis.

[0057] Fig. 2 shows a schematic representation of the essential elements of the print head 1 according to the invention in a lateral cross-sectional view, wherein a housing that is usually present is not shown for the sake of clarity. From bottom (distal) to top (proximal), the cross-sectional view shows a printing nozzle with the heating device 3 following (proximally). The distal end or the distal end region of the material transport screw 5 is conically tapered and ends in the transition to the heating device 3. The material transport screw 5 extends in a transport chamber (also called an extruder chamber), which begins just above the heating device and extends distally (here: above) to the feed chamber 10. Above this (proximal) follows the feed chamber 10, into which the printing material, preferably pellets, granules and / or powder, is fed into the feed chamber 10 via the hopper 7a.The screw 5 extends further upward (proximally) through the feed chamber 10 and is mounted in the region of its upper (proximal) end by the holder 6, rotatable and centered about its longitudinal direction. In the present embodiment, the holder 6 comprises part of the screw thread and part of the screw (countersunk) head 5a. In the embodiment shown, the hopper 7a, feed chamber 10, screw holder 6, and approximately the upper (proximal) part (i.e., behind the cooling device in the proximal direction) of the transport chamber are arranged in a feed housing 7. The material transport screw 5, with the exception of the screw head 5a, is provided with a self-tapping thread.

[0058] Fig. 3 shows a schematic representation of individual parts of the print head according to the invention, wherein the material transport screw 5, which comprises a Torx countersunk head 5a, and the drive element, which comprises a Torx screw drive 8a, have not yet been inserted into the feed housing 7, in which, as described above with reference to Fig. 2, the hopper 7a, feed chamber 10, screw holder 6, and approximately the upper (proximal) part (in the proximal direction, therefore behind the cooling device) of the transport chamber are arranged. The drive element 8 with screw drive 8a is designed as a bit, which enables quick changing of the drive and screw type.

[0059] Fig. 4 shows in a further schematic representation the elements of Fig. 3, wherein the drive element 8 with the Torx drive 8a is inserted into the drive device 9.

[0060] Fig. 5 shows a schematic representation of a material transport screw 5 inserted into the transport chamber located in the feed housing 7.

[0061] Fig. 6 shows a further schematic representation of the elements of the print head, similar to Fig. 1, in the assembled state. In particular, it can be seen how the Torx drive 8a of the drive element 8 engages positively with the corresponding Torx recesses of the countersunk head 5a of the material transport screw 5.

[0062] Figure 7 shows an oral dosage form of metoprolol succinate printed using the articles of the invention, in this case a biplanar object in the form of a tablet. (A) Top view of the printed tablet. (B) Side view of the printed tablet.

[0063] The present invention is further illustrated by the following non-limiting example.

[0064] EXAMPLE

[0065] Using a printing device according to the invention, two different metoprolol succinate formulations (A and B) were printed in tablet form by FDM.

[0066] Both formulations were initially prepared from powdered raw materials by geometric three-stage tumble mixing. Hot-melt extrusion was performed using a laboratory extruder (ZE HM99, Three Tec GmbH, Sion, Switzerland) with a die diameter of 2 mm. The extrusion temperature was 100 °C for formulation A and 140 °C for formulation B. The extrudate strands were comminuted by rasp screening with a U5 Comil® device (Quadro Engineering Corp., Waterloo, CA) at 250 rpm, yielding granules with particles with a diameter of 1 to 2 mm.

[0067] The following Table 1 shows the components and their proportions (in wt.%, based on the total weight of the respective formulation) of formulations A and B.

[0068] Tab. 1 : Composition of formulations A and B

[0069] Formulation MSN KVA64 EPO PEG

[0070] [Wt.%] [Wt.%] [Wt.%] [Wt.%]

[0071] A 25 65 - 5

[0072] B 25 - 75 -

[0073] MSN: Metoprolol succinate (pharmaceutically active ingredient)

[0074] KVA64: Kollidon VA64 (vinylpyrrolidone-vinyl acetate copolymer;

[0075] carrier polymer)

[0076] EPO: Eudragit E PO (anionic copolymer of methacrylic acid and

[0077] Methyl methacrylate; carrier polymer)

[0078] PEG: Lixopol 6000 (polyethylene glycol; plasticizer)

[0079] The parameters of the extrusion screws (material transport screws) used were varied as shown in Table 2 below. The screws can process both granules and powders.

[0080] Tab. 2: Parameters (ranges) of the extrusion screws used.

[0081] Properties Parameter value (range)

[0082] Number of screws in extrusion channel 1

[0083] Screw length [mm] 40 - 90

[0084] Screw outer diameter [mm] 4.0 - 5.0

[0085] Screw outer core diameter [mm] 2.0 - 4.0

[0086] Screw pitch angle [°] 5 - 50

[0087] Screw pitch [mm] 1.0 - 4.0

[0088] Screw channel depth [mm] 0.5 - 3.0

[0089] Screw pitch [mm] 0.1 - 2.0

[0090] Tablets were printed from the resulting granules by FDM using a print head according to the invention as part of a printing device according to the invention. The print throughput at the print nozzle (print volume per unit time) was 1.131 mm 3 / s and the speed of the print nozzle movement was 25 mm / s. The printing temperatures were varied between 140°C and 160°C. The temperature of the printing surface of the printing table was 50°C. An exemplary dosage form obtained by the printing process is shown in Fig. 7A (top view) and 7B (side view). List of reference symbols:

[0091] 1 print head

[0092] 2 pressure nozzle

[0093] 3 Heating device

[0094] 4 Cooling device 5 Material transport screw

[0095] 5a Head

[0096] 6 screw holder

[0097] 7 Feed housing

[0098] 7a Pouring device 8 Drive element

[0099] 8a screw drive

[0100] 9 Drive device

[0101] 10 Feed chamber

Claims

Claims Print head for additive manufacturing processes, comprising - a pressure nozzle (2) and - a material feed device with (i) at least one material transport screw (5) designed to move particulate printing material into the print nozzle (2) by rotation about its longitudinal axis, and (ii) at least one drive device (9) for the at least one material transport screw (5), wherein the at least one material transport screw has a proximal end driven by the drive device and a distal end from which the printing material is transported into the print nozzle (2), characterized in that the at least one material transport screw (5) has a standard thread or a self-tapping thread at least on a section that includes the distal end of the material screw. Print head according to claim 1, wherein the thread of the material transport screw (5) has a core diameter of 2.0 to 30 mm.Print head according to claim 1 or 2, wherein the proximal end of the material transport screw (5) has a shape and / or at least one recess designed to drive the material transport screw (5) by the drive device (9). Print head according to one of the preceding claims, wherein the length of the thread of the material transport screw (5) is 30 mm to 100 mm. Print head according to one of the preceding claims, wherein the standard thread of the material transport screw (5) is selected from M2 to M20 according to DIN 13-1 (1999-11). Print head according to one of claims 1 to 4, wherein the self-tapping thread is a wood screw thread.

7. Print head according to claim 6, wherein the wood screw thread of the material transport screw is selected from H3 to H20 according to DIN 7988 (1975-02).

8. Print head according to one of the preceding claims, wherein the flanks of the standard thread or the self-forming thread of the material transport screw (5) are at least approximately trapezoidal, conical or spherical.

9. Print head according to one of claims 1 to 4, wherein the standard thread of the material transport screw (5) is selected from M5 to M20 according to DIN 158-1 (1997-06).

10. Print head according to one of the preceding claims, wherein the proximal end of the material transport screw (5) comprises a screw head (5a) having a shape and / or at least one recess designed to drive the material transport screw (5) by the drive device.

11. Print head according to claim 10, wherein the shape of the screw head (5a) is selected from lens head, plate head, countersunk head, square, hexagon, round head, pan head and cylinder head.

12. Print head according to one of the preceding claims, wherein the proximal end of the material transport screw (5), preferably the screw head (5a), has a drive shape selected from external square, internal square, external hexagon, internal hexagon, slotted, Phillips, Pozidriv, internal hexalobular, external hexalobular, Mortorq, Torx-Plus, LocTec and Secloc drives.

13. Print head according to one of the preceding claims, wherein the drive device (9) has a drive element (8) which engages or engages in a form-fitting manner on / in the proximal end of the material transport screw (5), preferably on / in the screw head (5a).

14. Print head according to claim 13, wherein the drive element (8) is detachably connected to the drive device (9).

15. Print head according to claim 14, wherein the drive element (8) is detachably connected to the drive device (9) via a change mechanism. A print head according to claim 15, wherein the drive element (8) is configured as a bit, and the drive device has a recess configured for the positive reception of the bit. A printing device for additive manufacturing processes, comprising one or more print heads (1) according to any one of the preceding claims and a print bed having a printing table with a printing surface. A kit containing at least one print head (1) for additive manufacturing processes, comprising a print nozzle (2) and a material feed device configured to receive at least one material transport screw (5), a drive device (9) for the material transport screw (5), and at least one material transport screw (5) configured to move particulate printing material into the print nozzle (2) by rotation about its longitudinal axis when the material transport screw (5) is arranged in the material feed device.wherein the material transport screw (5) has a proximal end driven by the drive device (9) and a distal end from which the printing material is transported into the printing nozzle (2) when the material transport screw is arranged in the material feed device, characterized in that the material transport screw (5) has a standard thread or a self-tapping thread at least on a section that includes the distal end of the material transport screw (5). A kit containing at least one print head according to one of claims 1 to 16 and at least one further material transport screw (5) designed to move particulate printing material into the printing nozzle (2) by rotation about its longitudinal axis when the further material transport screw is arranged in the material feed device, wherein the material transport screw (5) has a proximal end driven by the drive device (9).and has a distal end of, from which the printing material is transported into the printing nozzle (2) when the material transport screw (5) is arranged in the material feed device (9), characterized in that the further material transport screw (5) has a standard thread or a self-tapping thread at least on a section that includes the distal end of the material transport screw (5). Kit according to claim 18 or 19, wherein the material screw(s) is / are defined according to one of claims 2 to 12. Additive manufacturing method, preferably for 2D and / or 3D printing, for producing an object, wherein the method comprises the step of printing a particulate printing material, preferably pellets, granules and / or powder, using the printing device according to claim 17.