Method for operating a print head of a 3D printer and print head of a 3D printer for performing the method

Abstract

A method (200) for operating a print head (100) of a 3D printer. The method comprises the following steps: - filling (210) a cavity (40) with a printable material (10) by a supply device (2), - closing (220) an open cross section (21) of a piston sleeve (4) by a feed of a piston (3) from a starting position (3a) in the direction of a nozzle (8) of the print head (100), - converting (230) the material from a solid phase (10) via a plastic phase (11) into a liquid phase (12), - compressing (240) the material, - determining (250) a spring constant of the liquid phase, - preparing (260) the liquid phase for printing, - outputting (270) the liquid phase of the material from the nozzle for printing a three-dimensional component (9), - moving the piston (3) back (280) into the starting position (3a), and - repeating (290) the steps (210) to (280) until the method ends. A print head (100) for a 3D printer for carrying out the method according to the invention.

Description

Technical Field

[0001] The present invention relates to a method for operating a printhead of a 3D printer and a printhead of a 3D printer for performing the method. Background Technology

[0002] A 3D printer for materials with variable viscosity obtains the solid phase of the material as the initial material, thereby generating a liquid phase, and selectively applies this liquid phase to portions belonging to the object to be produced. Such a 3D printer includes a print head in which the initial material is pre-treated in a print-ready manner. Furthermore, it is equipped with devices for generating relative movement between the print head and a working surface on which the object should be produced. Here, it is possible to move either only the print head, only the working surface, or both the print head and the working surface.

[0003] The printhead has a first operating state and a second operating state. In the first operating state, liquid material exits the printhead, and in the second operating state, no liquid material exits the printhead. For example, the second operating state is occupied when the printhead should move to another location on the work surface and no material should be output on the path to that location. The printhead can be switched between the two operating states, for example, by turning the propulsion of the initial solid material on or off.

[0004] The most widely used method is fused deposition modeling (FDM), in which filaments of initial material are melted in an electrically heated extruder nozzle and applied layer by layer to a platform. Initial materials in this filament form are very expensive.

[0005] US2016 / 082 627A1 proposes that the initial material is supplied in granular form and conveyed to the heated zone by means of a screw conveyor, and the initial material exits the heated zone in a plasticized form. On the one hand, granular materials are significantly cheaper, and on the other hand, mixtures composed of different thermoplastic materials can be easily manufactured in this way.

[0006] Furthermore, a printhead is known from DE 102016222306 A1, in which particulate material is plasticized by a piston and a heated section. If the piston is pressed against the particulate material, the particulate material is compressed and conveyed to a plasticizing zone in the lower region of the printhead. Here, a force arises that exerts a strong load on the piston and the cylindrical wall of the printhead and leads to increased wear on the cylindrical wall of the printhead housing. Additionally, a complex melting geometry with a heat-conducting structure is disclosed, wherein the heating power of a heating element is introduced into the plasticized material to bring it into the liquid phase of the material. Summary of the Invention

[0007] Based on the following objective, this invention provides a method for operating a printhead of a 3D printer and a printhead for a 3D printer, wherein the method and the printhead enable a highly dynamic and stable printing process.

[0008] Within the scope of this invention, a method for operating a printhead of a 3D printer has been developed. Furthermore, a printhead for a 3D printer has been developed for performing the aforementioned method.

[0009] According to the present invention, the method includes the following steps:

[0010] - The cavity is filled with printable material via a supply device.

[0011] -The opening cross-section of the piston sleeve is closed by the piston being fed from its initial position toward the nozzle of the print head.

[0012] - Transforming materials from a solid phase to a liquid phase via a plastic phase.

[0013] -Compressed material,

[0014] - Determine the spring constant for the liquid phase.

[0015] -Prepare for liquid phase printing.

[0016] - The liquid phase of material is output from the nozzle for printing three-dimensional components.

[0017] - Move the piston back to its starting position, and

[0018] - Repeat the steps described above until the method is completed.

[0019] In an extended embodiment of the invention, at least the closure, transformation, compression, determination of the spring constant, printing preparation, and output are performed by active adjustment of the actuator device by a control and regulation unit, wherein the results obtained by the evaluation unit from the sensor measurements are transmitted to the control and regulation unit.

[0020] The present invention also relates to a printhead for a 3D printer, the printhead being used to perform the method according to the invention. The printhead includes an actuator device disposed in a housing of the printhead, a material supply device for printable material, a flange having a cooling device, a nozzle head having a heating element, and a nozzle. The actuator device is used to control a piston. The flange is disposed on the housing and the supply device. The heating element is used to convert material from a solid phase via a plastic phase to a liquid phase. The nozzle is used to output the liquid phase of material from the nozzle head. According to the invention, a control and adjustment unit is provided for actively adjusting the actuator device to move the piston for filling and printing according to the operating strategy to be implemented and for actively adjusting the heating element.

[0021] In one extended version of the printhead, the evaluation unit is configured to evaluate the sensor measurements and transmit the results to the control and regulation unit to actively adjust the actuator device and the heating element.

[0022] The evaluation unit can be implemented separately from the control and regulation unit, or it can be integrated into the control and regulation unit.

[0023] By detecting and evaluating sensor values ​​according to various operating states, the functionality of the printhead can be verified, thereby advantageously enabling early detection of errors or deviations in the process. Furthermore, defined target values ​​can be manipulated by detecting sensor values. Alternatively, correction coefficients can be calculated and transmitted to the control and regulation unit. These correction coefficients can, for example, be added to a rated value to advantageously achieve the desired and constant output of melt from the nozzle. Active regulation of the heating element enables dynamic temperature control, which advantageously affects not only heating but also cooling. For example, if the heating energy of the first heating element is reduced by the control and regulation unit, the cooling device in the flange continues to operate, and this cooling device absorbs energy from the plastic phase of the material, thereby causing the plastic phase to cool abruptly. Furthermore, active regulation of the actuator device and heating element enables the material to be discharged from the nozzle as needed, wherein the actively regulated volume of discharged material can compensate for different trajectory speeds of the printhead. Therefore, active regulation offers advantages over common NC systems, which consistently discharge the same volume or control the amount to be discharged at a constant feed rate regardless of their trajectory speed, without actively regulating the process.

[0024] The actuator used to control the piston can be, for example, an electric motor with a mechanical transmission ratio or a hydraulic actuator with a hydraulic pressure source.

[0025] Compared to hydraulic drives, electric motors, as actuators, have a smaller weight and thus advantageously generate high dynamism throughout the printer and printing process because the mass to be accelerated is very small.

[0026] Hydraulic actuators deliver large forces in a favorable manner when manipulating the piston.

[0027] The supply device for printable materials can be configured to supply materials that exist as particulate materials or initial materials. The initial material can be, in particular, a thermoplastic material.

[0028] It has been recognized that using particulate materials as the initial material offers particular advantages, especially in terms of cost of initial materials for printers, compared to printheads using filaments made of thermoplastic materials.

[0029] Compared to printheads that transport granular material using a screw conveyor, the printhead according to the invention can be constructed more compactly. This, in turn, results in a lighter and simpler printhead movement. This is particularly advantageous when the printhead needs to move very quickly, especially at speeds of 100 mm / s or higher.

[0030] The flange includes a cooling device, thereby achieving optimized thermal management in the area of ​​the supply device and advantageously preventing material, or particulate material, from adhering to the piston. Furthermore, the nozzle head has a heating element for converting the material from a solid phase, especially particulate material, into a liquid phase. The heating element in the nozzle head advantageously directs heating power to the material to be melted. Subsequently, the liquid phase, or melt, can be output through the nozzle of the nozzle head due to piston movement.

[0031] The piston sleeve is implemented as a separate piston sleeve for guiding the piston, and it is possible to guide the piston directly within the piston sleeve and no longer within the housing or the cylinder of the printhead. This advantageously prevents wear from occurring directly on the inner wall of the housing or cylinder, but rather within the piston sleeve. The piston sleeve as a separate component offers the advantage that it can be replaced when needed. Furthermore, it allows for the use of pistons and piston sleeves of different diameters without additional structural changes, such as modifications to the flange and nozzle head.

[0032] In an extended embodiment of this method, the cavity, particularly a heatable cavity, is filled with a printable material via a supply device, the filling comprising at least the following steps:

[0033] - The material or granular material block is fed into the print head through the opening of the supply device.

[0034] - Generates air pulses to separate the granular material blocks from each other.

[0035] In one extended scheme, the filling of granular material blocks is performed manually or automatically, wherein the granular material blocks slide into the lower region of the supply device due to gravity.

[0036] In a preferred extension of the filling process, air pulses are generated intermittently, and the particulate material blocks are thrown up in the area of ​​the air pulses, such that when the particulate material blocks fall back down, pulses are applied to the particulate material blocks below and these particulate material blocks are induced to continue sliding into the heated cavity of the printhead.

[0037] An effective refill process requires blowing particulate material from the rear, which lifts the material and allows it to slide into the printhead. Throwing or swirling the material is essential for automation, and the resulting gravitational impulse or impact propels the material to continue sliding advantageously. When necessary, air pulses can also dislodge stuck material, thus minimizing printhead downtime.

[0038] In an extended embodiment of the method, the opening cross-section of the piston sleeve is closed by a piston, the closing comprising the following steps:

[0039] - Feed the piston, starting from the bottom of the piston and moving towards the nozzle until it reaches a position below the cut in the piston sleeve, where,

[0040] - Particulate material is sheared by allowing the bottom of the piston to slide past the cut.

[0041] The piston sleeve has an upper region extending into the flange and a lower region extending into the nozzle head. Thus, the upper region is positioned within the cooling zone of the flange's cooling device, while the lower region is positioned within the heating zone of the nozzle head, thereby advantageously enabling efficient energy extraction from the material in the cooling zone or efficient energy supply to the material in the heating zone. An opening, or opening cross-section, is provided in the upper region of the piston sleeve, allowing material to be supplied from the supply device into the piston sleeve. A cut is provided in the lower region of the opening, constructed at an obtuse angle to the inner surface of the piston sleeve. The area of ​​the cut is hardened or alternatively implemented as a separate hardened insert. When the piston closes the opening, the material, or particulate material, is sheared by the piston at the cut, thereby applying a strong mechanical load to this portion of the piston sleeve. The separate piston sleeve and the hardened area of ​​the cut advantageously enable a longer service life and faster replacement of faulty components.

[0042] In an extended embodiment of the method, the material is transformed from a solid phase to a liquid phase via a plastic phase, the transformation comprising the following steps:

[0043] - The material is heated in the state zone of the printhead by a heating element in the nozzle head, wherein the state zone represents the material and its temperature T. S The relevant aggregation state, and by introducing heating energy from the heating element, the aggregation state of the material is realized from the solid phase through the plastic phase to the liquid phase in the state region.

[0044] - The materials are mixed during the compression.

[0045] The printhead, starting from the upper part of the piston sleeve, passes through the kidney-shaped element to the nozzle, and has different state zones, where these state zones exhibit the material's properties related to its temperature T. S The associated aggregated state. Here, the aggregated state of the material can change from a solid phase to a liquid phase in the state region via a plastic phase.

[0046] Advantageously, the state zone of the printhead includes a cold zone with material in the solid phase, a plasticizing zone with material in the plastic phase, a melting zone and a process zone with material in the liquid phase, and a mixing zone with material in the plastic and liquid phases.

[0047] Furthermore, the cooling devices in the flange and the piston cooling device integrated in the piston are configured to cool the plastic phase of the material in the plasticizing zone to a temperature T. S Then it is also kept below the glass transition temperature T. g From this glass transition temperature, the material will plasticize and transform into a liquid phase.

[0048] This is advantageously equivalent to the piston bottom contacting only the solid phase of the material, and not the fully plasticized phase. The fully plasticized phase has a tough, viscous consistency and a high tendency to adhere to surfaces. If the piston were to contact this phase, it would stick to it, thereby, for example, hindering the reflow of fresh particulate material when the piston is pulled back. This effect is advantageously avoided.

[0049] To perform the method, the nozzle head includes two heating zones.

[0050] The first heating zone includes a portion of a plasticizing zone, a mixing zone, and a melting zone. The first heating element is arranged in the upper nozzle head such that heating energy can be introduced into the material from the first heating element through the lower portion of the piston sleeve, the kidney-shaped part, and a portion of the upper nozzle head.

[0051] The second heating zone includes a portion of the melting zone and a process zone. The second heating element is arranged in the lower nozzle head such that heating energy can be introduced from the second heating element into the liquid phase of the material through the lower nozzle head.

[0052] The arrangement of two heating zones in the nozzle head results in more efficient thermal management of the printhead because heating in the first heating zone induces beneficial pre-plasticization of the material without it transforming into a liquid phase. This advantageously prevents the piston from sticking during compression and ensures trouble-free operation of the printhead. This effect is further optimized in conjunction with a cooling device in the flange. Furthermore, the pre-plasticization of the material in the plastic phase reduces the force required by the actuator device during piston feed, thereby enabling the use of a smaller actuator for piston feed. This reduces equipment costs and leads to improved printhead dynamics due to the reduced printhead weight. Consequently, the printhead can be better accelerated and braked during so-called trajectory control for producing components.

[0053] A melt is generated in the second heating zone, and the input heating causes a relatively constant melting temperature throughout the melting chamber. The melting temperature can be adjusted within the second heating zone so that the material is not overheated. This advantageously avoids the generation of fission products, primarily gases, through excessive heat load, which accelerates further decomposition of the material by the dominant pressure in the system and also directly and negatively affects the quality of the material.

[0054] The compression and conversion processes largely occur simultaneously because heating energy is introduced into the printhead via two heating zones during the two processes.

[0055] In a preferred extension of the invention, the compression of the material during the compression process includes the following steps:

[0056] -Pre-compressed material is fed through the piston.

[0057] -Close the nozzle,

[0058] -The material is compressed by the piston feed.

[0059] - Keep the piston in the holding position.

[0060] In an extended scheme of the compression process, pre-compression of the material is performed in a controlled manner by the feed pressure and / or force of the piston, wherein the pre-compression is reached when the material-related slope and / or inclination angle of the force curve and / or pressure curve is reached and / or exceeded.

[0061] In the next step of the process, the material is compressed in a controlled manner by the feed pressure of the piston while the nozzle is closed, and then moved to the holding position until the peak pressure is reached.

[0062] In one extended embodiment, during compression, the nozzle is closed and the piston needle is submerged into the melting chamber of the nozzle head, thereby squeezing a portion of the liquid phase from the upper region of the melting chamber back into the mixing zone through the opening of the kidney-shaped member, whereby this portion of the liquid phase mixes with the plastic phase from the plasticizing zone in the mixing zone.

[0063] In one extended scheme, the piston is held in a holding position, during which the pressure and temperature of the liquid phase are measured, and the measurements are verified by an evaluation unit to perform a functional check on the compression process.

[0064] Furthermore, in an extended embodiment, while the piston is held in the holding position, the nozzle is closed and the piston needle is submerged into the melting chamber, thereby squeezing a portion of the liquid phase from the upper region of the melting chamber back into the mixing zone through the opening of the kidney-shaped member, whereby this portion of the liquid phase is mixed with the plastic phase from the plasticizing zone in the mixing zone.

[0065] Pre-compression is achieved by force- or pressure-controlled piston manipulation via an actuator, wherein the target position of the piston bottom, starting from the cold zone, is in the first third of the plasticizing zone. The granular material is compressed by the piston feed in the plasticizing zone, while simultaneously, melt exists between the cavity and the nozzle in the melting zone. The plasticized granular material is then forced into the melt in the mixing zone.

[0066] By lowering the piston and similarly the piston needle toward the nozzle, the melt has exited the nozzle, thereby advantageously expelling any remaining air or air inclusions from the nozzle head. Thus, the nozzle becomes empty.

[0067] After reaching the target position for pre-compression, the nozzles of the printhead are closed.

[0068] To compress the material, the piston is pressure-controlled and fed via an actuator until a defined peak pressure is reached and the peak pressure position is achieved. In an extended embodiment of the method for operating the printhead, during compression, the nozzle is closed and the piston needle is submerged in the melting chamber, causing a portion of the liquid phase to be expelled from the upper region of the melting chamber through the opening of the kidney-shaped element back into the mixing zone. This portion of the liquid phase then mixes with the plastic phase from the plasticizing zone in the mixing zone.

[0069] Subsequently, a so-called peak pressure position is maintained for a predetermined period of time related to the material; therefore, this peak pressure position is also the holding position of the printhead.

[0070] In an extended embodiment of the method, while the piston is held in the holding position, the nozzle is closed and the piston needle is submerged into the melting chamber, thereby squeezing a portion of the liquid phase from the upper region of the melting chamber back into the mixing zone through the opening of the kidney-shaped member, whereby this portion of the liquid phase is mixed with the plastic phase from the plasticizing zone in the mixing zone.

[0071] By maintaining the flow, residual air is expelled, and the melt is homogenized in mixing zone C. This results in a better energy flow and a more homogeneous material. The returning melt becomes plastic, and the granular material portion pushed into the kidney-shaped part becomes molten. This forms a material mixture.

[0072] Furthermore, the holding process described herein is advantageous for analysis and system inspection of the printhead because the following effects are achieved during pressure measurement: An increase in pressure within the melt will mean that the melt releases gas, for example, due to excessively high melt temperature. Excessively high melting temperatures are undesirable because they create air plasma, which leads to chemical decomposition.

[0073] A significant pressure drop in melt pressure can indicate, for example, that the printhead system is not sealed or that there is too much air in the system. This effect occurs when, for example, there is too much cold material in the cavity due to unoptimized printhead temperature management.

[0074] In one extended scheme, the determination of the spring constant of the liquid phase includes the following steps:

[0075] - After the holding position ends, the melt is pressure-controlled to move back to a target position, reaching the target position when the melt pressure reaches the target pressure.

[0076] - Calculate the pressure difference between the peak pressure and the target pressure.

[0077] - Calculate the distance between the maintained position and the target position.

[0078] - Calculate the spring constant of the liquid phase.

[0079] The spring constant is derived from the compressibility of the melt and results in a correction factor, or shape factor, which is required to precisely control the piston via the actuator mechanism.

[0080] Due to the compressibility of the melt, geometrically, 1.2 volume units of the piston stroke corresponds, for example, to 1.0 volume unit of the volume of melt discharged. In the case of incompressibility, this ratio is 1:1.

[0081] This is achieved advantageously by determining the spring constant of the melt: the actuator device can be adjusted to control the piston, wherein the spring constant, in particular, enables the actual discharge of the melt to achieve the correct, calculated volumetric flow of the melt according to the trajectory velocity of the print head moving during printing. That is, at each printing position, at each trajectory velocity of the print head, the respective required amount of melt is applied to the component.

[0082] In one extended approach, liquid phase printing preparation includes the following steps:

[0083] - By pulling the piston back according to the spring constant, the liquid phase is actively decompressed.

[0084] - Open the nozzle, and

[0085] - Compress the liquid phase at the start of printing.

[0086] In the case of active decompression, the piston is pulled back by about 1 to 2 millimeters according to the determined spring constant, thereby advantageously achieving that if the nozzle or nozzle opening is opened at this point, no melt exits from the nozzle or nozzle opening. This will be the case when the position is maintained due to the influence of gravity on the existing open system. Meanwhile, the melt is unloaded similarly to a spring.

[0087] Subsequently, further printing preparation begins through compression. The entire printhead system is a compressible system because the melt can, for example, be compressed to about 20%. Therefore, the volume expelled by the piston feed does not correspond to the volume of material discharged, resulting in inaccurate and uneven discharge. However, this is advantageously avoided by performing the method according to the invention.

[0088] In one extended scheme, pressure is regulated to perform the output of the liquid phase, i.e., printing, wherein:

[0089] -Continuously measure the pressure in the melting chamber,

[0090] - The piston is actively manipulated by a control and adjustment unit, wherein the piston feed is adapted to pressure with a correction factor, wherein the correction factor is derived from the spring constant of the liquid phase of the material.

[0091] The measured pressure corresponds to the pressure generated by discharging the liquid phase onto the component, and a correction factor is advantageous to compensate for the compressibility of the liquid phase.

[0092] At the start of printing, the compression of the melt in the melting chamber is partly generated by friction at the nozzle opening of the nozzle as the melt is “extruded”, and partly by resistance as it is printed onto the component or substrate carrier on which the component is constructed.

[0093] Uniform discharge of the melt is achieved through intelligent adjustment of the printhead, wherein the asynchronous movement of the piston, adapted with a correction coefficient, is realized by using an electronic drive on the actuator device. In particular, the correction coefficient, derived from the spring constant of the melt, is essentially incorporated into the system. Therefore, the method according to the invention advantageously avoids the limitations on synchronous movement common in conventional NC systems.

[0094] Electrically driven actuators have proven to be dynamic and highly effective for this situation.

[0095] Furthermore, the method is able to achieve a constant, unchanging trajectory thickness from the very first drop in an advantageous manner.

[0096] Furthermore, the printhead construction offers advantages, wherein the piston sleeve can have a stop between its upper and lower regions, by which the flange and nozzle head are separated from each other. Thus, the piston sleeve and, in particular, the stop, advantageously separate the cooled flange from the heated nozzle head, thereby preventing the flange and nozzle head from contacting each other. Additionally, a kidney-shaped element with a centrally extending hole can be arranged on the lower region of the piston sleeve to receive the piston pin.

[0097] The piston of the printhead includes a first piston member for attachment to the actuator assembly and a piston head for attachment to the first piston member and for receiving the piston needle. Preferably, the first piston member is constructed as a hollow aluminum piston, thereby allowing coolant to be guided through the first piston member and thus advantageously cooling the piston. The piston head has a lower side on the nozzle-facing side, from which the piston needle extends from the middle. The lower side of the piston head minus the virtual surface of the piston needle forms a piston surface for generating pressure acting on the material. The lower side of the piston head is cooled together by a piston cooling device, thereby locally reducing the viscosity of the melt, or plastic material, at the bottom of the piston. This prevents the liquid melt from flowing towards the drive unit, thereby advantageously preventing the piston from jamming in the piston sleeve and preventing the melt from entering the drive unit. Furthermore, during the pull-back, the material is more easily detached from the bottom of the piston or the underside of the piston head, allowing the material or particulate material in the solid phase to be easily refilled when the piston reaches its starting point, while the remaining material does not adhere to the bottom of the piston.

[0098] Preferably, a temperature sensor is mounted on the underside of the piston head, or on the bottom of the piston. This arrangement of the temperature sensor enables thermal management of the printhead in relation to the piston position, thereby achieving faster heating of the material without the melt contacting the underside of the piston head. This advantageously accelerates the filling process of the printhead. The piston head is implemented as a cylindrical member and is preferably made of a heat-resistant material. An embodiment where the first piston member is made of aluminum and the piston head, for example, is made of steel has proven advantageous because the piston thus has an elastic upper region for receiving mechanical stress and a heat-resistant lower region in the area of ​​the heated material.

[0099] Depending on the piston position, the piston needle may be inserted only partially into or completely through the hole in the kidney-shaped part, thereby being advantageously guided in the central hole of the kidney-shaped part.

[0100] The kidney-shaped component has concentrically arranged openings, wherein the openings form a fluid connection between a cavity arranged in the piston sleeve and a melting chamber arranged in the lower part of the nozzle head.

[0101] A cavity is arranged within the piston sleeve and formed by a volume whose outer surface is formed by the inner side of the piston sleeve, the outer side of the piston needle, the upper side of the kidney-shaped element, and the lower side of the piston. Within the cavity, the material, or particulate material, is compressed by the movement of the piston through the lower side of the piston head, or piston face. During material compression, the thermal management of the printhead is adjusted so that a liquid phase or melt of the material does not form within the cavity, but rather the material is structured as a plastic phase. This advantageously prevents the plasticized material from adhering to the lower side of the piston. However, during compression, a portion of the liquid phase or melt in the melting chamber is forced from the melting chamber through the concentrically arranged openings of the kidney-shaped element into the cavity of the piston sleeve via the piston needle that penetrates the melting chamber. Here, this portion of the melt mixes with a portion of the plastic phase. Here, the melt releases energy into the plastic phase, thereby advantageously producing a more homogeneous material. Therefore, the kidney-shaped component constitutes a mixer, or a static mixer, because advantageously, no other moving parts are needed for mixing the plastic phase and the liquid phase, except for the piston movement. Thus, the kidney-shaped configuration advantageously induces a perforation effect, which leads to better and more complete mixing of the material, or melt, with the plasticized material.

[0102] The kidney-shaped element transfers the heating energy from the nozzle head not only to the melt but also to the piston needle, which advantageously results in improved energy management when heating the melt.

[0103] Furthermore, the kidney-shaped component can be implemented as a separate component or constructed integrally with the piston sleeve.

[0104] In addition, a pressure p for the liquid phase is arranged in the melting chamber. L Pressure sensors and / or temperature sensors for the liquid phase T L Temperature sensor.

[0105] For pressure p L The measurement of temperature T is a key parameter that determines the mass flow of the melt output, or rather, discharged or exiting the effluent opening. L Additional measurements are possible, taking into account the temperature dependence of material viscosity when determining the mass flow Q. The amount to be dispensed can be precisely adjusted via piston feeding. For the mass of the manufactured component or object, the temperature T... L Control, especially control in the form of constant and precise regulation, is even more important to avoid thermal degradation of the material. Furthermore, the actuator assembly and / or the piston are equipped with a displacement measuring system for the piston's position s and / or a system for measuring the force F applied by the piston to the material or the hydraulic pressure p applied to the piston. H The sensor.

[0106] The piston feed is a measure of the amount of material to be discharged. This amount can be controlled, in particular, by a displacement measurement system. Furthermore, the force F is directly related to the pressure within the material.

[0107] Furthermore, a temperature T for the plastic phase of the material is arranged on the piston, especially on the lower side of the piston head. K The temperature sensor, due to its arrangement, enables printhead thermal management related to the piston position, thereby achieving faster material heating without the melt contacting the underside of the piston head. This advantageously accelerates the printhead filling process or reduces the filling time required. Attached Figure Description

[0108] Other measures to improve the invention are shown in more detail below, together with the description of preferred embodiments of the invention with reference to the accompanying drawings.

[0109] It shows:

[0110] Figure 1 The printhead according to the present invention;

[0111] Figure 2 Another illustration of the printhead according to the invention;

[0112] Figure 3 A portion of the printhead according to the present invention;

[0113] Figure 4 A schematic illustration of a printhead according to the present invention;

[0114] Figure 5 A flowchart of a method for operating a printhead according to the present invention;

[0115] Figure 6 The local area of ​​the printhead according to the present invention, including the pressure direction;

[0116] Figure 7 Different positions of the piston in the printhead according to the present invention;

[0117] Figure 8 A graph showing the piston stroke, printhead trajectory speed, and pressure direction;

[0118] Figure 9 A flowchart of a method for filling the cavity in a printhead;

[0119] Figure 10 Flowchart of a method for closing the open cross-section of a piston sleeve for a printhead;

[0120] Figure 11 Flowchart of a method for transforming a material from a solid phase to a liquid phase via a plastic phase;

[0121] Figure 12 Flowchart of a method for compressing materials;

[0122] Figure 13 A flowchart of a method for determining the spring constant of the liquid phase of a material;

[0123] Figure 14 A flowchart of a method for preparing materials for liquid phase printing; and

[0124] Figure 15 Flowchart of a method for outputting liquid phase. Detailed Implementation

[0125] Figure 1 A printhead 100 for a 3D printer is shown. The printhead includes an actuator device 110 disposed within a housing 1 of the printhead 100, a supply device 2 for printable material 10, a flange 5 having a cooling device 50, a nozzle head 6 having heating elements 61 and 63, and a nozzle 8. The actuator device is used to operate a piston 3. The flange is disposed on the housing 1 and the supply device 2. The heating elements are used to convert the material 10 from a solid phase 10 via a plastic phase 11 into a liquid phase 12. The nozzle is used to output the liquid phase 12 of the material 10 from the nozzle head 6. The printhead 100 includes a separate piston sleeve 4 for guiding the piston 3.

[0126] The flange 5, which is internally cooled by the cooling device 50, causes thermal isolation between the heated lower region of the printhead 100 and the actuator device 110, or the driver of the piston 3.

[0127] Piston 3 includes a first piston member 31 and a piston head 34. The first piston member is used to attach piston 3 to actuator device 110. The piston head is fastened to the first piston member 31 and receives piston needle 32 in the direction of nozzle 8. A temperature sensor 36 is arranged on piston 3 or on the lower side 35 of piston head 34 for measuring the temperature T of plastic phase 11 of material. K The lower side 35 of the piston head 34 forms the piston bottom 35. Preferably, the first piston member 31 is constructed as a hollow aluminum piston, wherein the hollow aluminum piston has an internal cavity configured as a cooling channel. A piston cooling device 33 is arranged at the lower end of the first piston member 31, which is cooled by a coolant system. The piston cooling device 33 causes the materials 11, 12 to solidify on the piston bottom 35 and thereby seals the piston 3 toward the actuator device 110, or in other words, prevents the liquid melt 12 from flowing toward the actuator device 110. Preferably, a cooling liquid is used as the coolant, wherein the cooling liquid is delivered through the housing 1 to the cooling joint 37 of the first piston member 31 via a joint and flexible pipeline.

[0128] Coolant is supplied to the cooling device 50 in flange 5 through the same coolant system.

[0129] By cooling the materials 11 and 12 on the bottom 35 of the piston, the viscosity of the materials 11 and 12 is locally reduced, thereby causing the materials to detach from the piston when the piston 3 is pulled back without forming threads. Here, a space for new material 10 is created.

[0130] Figure 1 The piston 3 is shown in its initial position for filling the print head 100 with printable material 10, which is supplied to the print head 100 via the supply device 2.

[0131] The supply device 2 is funnel-shaped, in which material 10, preferably particulate material, is filled from above into the opening of the supply device 2. Material 10 reaches the opening 21, or the opening cross-section (to the piston sleeve 4), due to gravity. An air passage 20 is arranged above the opening 21 in the lower region of the supply device 2. This air passage is pulsed with air by a pneumatic valve 22. The pneumatic valve 22 and the air passage 20 constitute a blowing device that intermittently loads the particulate material 10 with air impact, causing the particulate material to be thrown upwards towards the upper region of the supply device 2, thereby separating the individual pieces of particulate material 10 from each other. When the airflow is cut off, the particulate material 10 in the lower region of the supply device 2 falls into the piston sleeve 4 as the opening cross-section 21 opens.

[0132] The blowing device of the supply unit 2 prevents the granular material block 10 from getting stuck, thereby preventing blockage of the supply unit 2, and the blowing device causes the piston sleeve 4 to be reliably filled with granular material 10. Furthermore, a smaller diameter can be used at the inlet of the supply unit 2. The refilling process requires blowing the granular material 10 from the rear, thereby creating an effect of lifting the granular material, which then slides into the print head 100. A spiraling lift is necessary for automated use, and the resulting gravitational impulse, or impact, causes the granular material 10 to continue sliding.

[0133] The piston sleeve 4 has an upper portion 41 extending into the flange 5 and a lower portion 42 extending into the upper portion 60 of the nozzle head 6. A stop 43 is arranged between the upper portion 41 and the lower portion 42 of the piston sleeve 4, by which the flange 5 and the nozzle head 6 are separated from each other. An opening 21, or opening cross-section, is arranged in the upper portion 41 of the piston sleeve 4 and has a cut 44 on the inner surface of the piston sleeve 4. The cut 44 causes the particulate material 10 to be sheared between the cut 44 and the piston bottom 35 when the piston 3 closes the opening cross-section 21, until the piston bottom 35 reaches a position below the cut 44.

[0134] The piston sleeve 4 has an obtuse angle at the cut 44, wherein the cut is sharp and hardened. Local hardening is advantageous here. In an alternative embodiment, the cut 44 can also be formed by a separate insert, similar to a rotary disc.

[0135] The structural shape of the notch 44 advantageously reduces the force required to shear the particulate material 10, thereby saving energy and making the materials of the piston sleeve 4 and piston 3 less prone to wear. However, the edges of the notch 44 are extremely susceptible to wear.

[0136] A kidney-shaped member 7 is arranged in the lower part region 42 of the piston sleeve 4, wherein the kidney-shaped member 7 has a centrally extending hole 70 for receiving the piston needle 32 of the piston 3.

[0137] Furthermore, the kidney-shaped member 7 has concentrically arranged openings 71 that form a fluid connection between a cavity 40 disposed in the piston sleeve 4 and a melting chamber 81 disposed in the lower portion 62 of the nozzle head 6. The cavity 40 is disposed within the piston sleeve 4 and is formed by the inner side of the piston sleeve 4, the outer side of the piston needle 32, the upper side of the kidney-shaped member 7, and the lower side 35 of the piston 3.

[0138] A preferred function of the kidney-shaped component 7 is to conduct heat or energy from the heating elements 61, 63 of the nozzle head 6 to the liquid phase 12 or melt 12 of the material. This is achieved, in particular, by increasing the contact surface with the cavity 40 and therefore with the plastic phase 11 of the material.

[0139] Another task is to guide the piston needle 32, wherein the contact of the piston needle 32 within the orifice 70 additionally causes the piston needle 32 to be heated to the desired process temperature. The final process temperature is only reached in the nozzle head 6 facing the nozzle 8.

[0140] During the filling process of the printhead 100, the nozzle 8 is closed when needed, and the materials 10, 11, 12 arranged in the cavity 40 and the melting chamber 81 are compressed by the piston feed when the piston 3 is operated by the actuator device 110.

[0141] The nozzle head 6 includes heating elements 61 and 63 of the print head 100, wherein the first heating element 61 is arranged in the upper nozzle head 60, and the second heating element 63 is arranged in the lower nozzle head 62. The upper nozzle head 60 has a partial section 64 arranged between the upper nozzle head 60 and the lower nozzle head 62, and the kidney-shaped member 7 is placed on this partial section. In the region of the nozzle 8, a cooling ring 84 is arranged on the nozzle head 6. This cooling ring cools the component to be printed and thermally shields the component from the print head 100.

[0142] Heating elements 61 and 63 in nozzle head 6 heat materials 10, 11, and 12 within cavity 40, kidney-shaped element 7, and melting chamber 82 until the liquid phase 12 of the material reaches its process temperature and can be discharged from nozzle 8. Melting chamber 82 is configured such that it tapers from a portion 64 of upper nozzle head 60 to nozzle 8. The conical convergence of melting chamber 81 increases volumetric flow and prevents material deposition on the inner wall of nozzle head 6. The mixing process is further optimized because the material 12 in the conically converged melting chamber 81, or rather, its smaller volume, compared to a cylindrical melting chamber 81. Thus, piston needle 32 only needs to displace a smaller volume to force a portion of the melt 12 back from melting chamber 81 into cavity 40 through opening 71 of kidney-shaped element 7 during compression.

[0143] In addition, the printhead 100 includes additional sensors, wherein pressure p is arranged in the melting chamber 81. L Pressure sensor 83 and temperature T of liquid phase 12 for material L Temperature sensor 82. Additional sensors are arranged on actuator device 110, including a displacement measurement system 111 for the position s of piston 3 and a force F applied by piston 3 to material 10 or a hydraulic pressure p applied to piston 3. H Sensor 112. In an alternative embodiment, sensors 111 and 112 can also be arranged on piston 3 of printhead 100.

[0144] Figure 2Another schematic diagram of a printhead 100 according to the invention is shown, wherein, according to the invention, the solid phase 10 of the material comprises particulate material blocks 10, and the supply device 2 has a blowing device 25 for separating the particulate material blocks 10 from each other.

[0145] The blowing device 25 includes a pneumatic valve 22 and an air passage 20, wherein the air passage 20 is arranged in the housing portion 27 of the supply device 2 and enters above the opening cross section 21 of the flange 5 in the lower region 24 of the supply device 2.

[0146] Air channel 20 can be loaded with air pulse 26 via pneumatic valve 22, wherein air pulse 26 acts on particulate material blocks 10 in lower region 24, causing these particulate material blocks to separate from each other.

[0147] The supply device 2 is funnel-shaped, in which granular material blocks 10 are filled from above into the opening 23 of the supply device 2. The material 10 reaches the cross-sectional opening 21 of the flange 5 leading to the piston sleeve 4, or the opening cross-section 21 of the piston sleeve 4, due to gravity. An air passage 20 of the blowing device 25 is arranged above the opening cross-section 21 of the flange 5 in the lower region 24 of the supply device 2. The air passage 20 is loaded with air pulses 26 via a pneumatic valve 22. The blowing device 25 includes the pneumatic valve 22 and the air passage 20, in which the granular material 10 is intermittently loaded with air impacts, causing the granular material to be thrown upwards towards the upper region of the supply device 2, thereby separating individual granular material blocks 10 from each other. When the blowing device 25 is closed, the granular material 10 in the lower region 24 of the supply device 2 falls into the cavity 40 of the piston sleeve 4 as the opening cross-section 21 opens.

[0148] The blowing device 25 of the supply device 2 prevents the granular material block 10 from getting stuck, thereby preventing blockage of the supply device 2, and the blowing device causes the piston sleeve 4 to be reliably filled with granular material 10. The refilling process requires blowing granular material 10 from the rear, thereby creating an effect of lifting the granular material, which then slides into the print head 100. The spiraling rise is necessary for automated use, and the resulting gravitational impulse or impact causes the granular material 10 to continue sliding.

[0149] Figure 3 A partial view of the printhead 100 according to the invention is shown in a 90° rotated view, wherein state zones A, B, C, D, and E of the printhead 10 filled with materials 10, 11, and 12 during operation are shown, extending from the upper portion 41 of the piston sleeve 4 through the kidney-shaped member 7 to the nozzle 8. State zones A, B, C, D, and E represent the material 10 and its temperature T. SThe relevant aggregated states, wherein the aggregated states of material 10 can change from solid phase 10 to liquid phase 12 via plastic phase 11 in state regions A, B, C, D, and E.

[0150] The temperature T of materials 10, 11, and 12 within printhead 100 S Alternatively, the temperature trend is shown in a graph above the printhead 100, where the graph shows the length of the travel s, or the working area 120 of the printhead 100.

[0151] The state zones A, B, C, D, and E of the printhead 100 include a cold zone A containing material in the solid phase 10, a plasticizing zone B containing material in the plastic phase 11, a melting zone D containing material in the liquid phase 12, and a process zone E. Furthermore, the state zone includes a mixing zone C containing material in the plastic phase 11 and the liquid phase 12.

[0152] A cooling device 50 is provided in the flange 5 and a piston cooling device 33 is integrated in the piston 3, so as to reduce the temperature T of the plastic phase 11 of the material in the plasticizing zone B. S Then it is also kept at the glass transition temperature T. g From this glass transition temperature, material 11 plasticizes and transforms into liquid phase 12. In the embodiment shown here, the plasticized region B of the material in plastic phase 11 illustrates the following state of the material, or particulate material: in this state, the viscosity of the particulate material has changed, thereby optimizing the compression and mixing process, but the plastic phase 11 of the particulate material has not yet transformed into liquid phase 12.

[0153] In addition, the nozzle head 6 includes two heating zones 65 and 66.

[0154] A portion of the plasticizing zone B, a mixing zone C, and a portion of the melting zone D are arranged in the first heating zone 65. The first heating element 61 is arranged in the upper nozzle head 60 such that heating energy can be introduced from the first heating element 61 into the materials 10, 11, and 12 through the lower portion 42 of the piston sleeve, the kidney-shaped member 7, and a portion 64 of the upper nozzle head.

[0155] A portion of the melting zone D and a process zone E are arranged in the second heating zone 66, wherein the second heating element 63 is arranged in the lower nozzle head 62 such that heating energy can be introduced from the second heating element 63 into the liquid phase 12 of the material via the lower nozzle head 62.

[0156] As can be seen from the graph, the temperature Ts of materials 10, 11, and 12 consistently rises during the stroke s of the working area 120 of the printhead 100. In the cold zone A, the cooling device 50 of the flange 5 plays a dominant role, thus the particulate material 10 is only slowly heated during the stroke s. From the plasticizing zone B onwards, the influence of the first heating zone 65 with the first heating element 61 begins to increase, in which the temperature curve rises sharply until it reaches the glass transition temperature T. g And the mixing zone C begins from there. Temperature T g The temperature continues to rise at a small slope in mixing zone C until it reaches melting zone D. There, the influence zone of the second heating zone 66, equipped with the second heating element 63, begins, wherein the second heating element maintains the temperature T of the melt 12. S The temperature rises sharply until the process temperature of melt 12 is reached in process zone E and a printable melt 12 is formed.

[0157] Temperature T S It must be configured so that the particulate material 10 can flow into the cavity 40 during filling without sticking, but is also preheated so that the material 10, 11 can be sheared at the cut 44 with the least possible force. Here, the temperature management of the printhead 100 is configured so that the cooling device 50 in the flange 5 introduces a cooling temperature of about 40°C into the piston sleeve 4 and thereby into the material 10, 11, and the first heating element 61 of the first heating zone 65 is below the glass transition temperature T. g Alternatively, the melting temperature of materials 10, 11, and 12 is adjusted by heating to approximately 30°C. This effect is supported by the piston cooling device 33. By cooling materials 11 and 12 on the piston bottom 35, the viscosity of materials 11 and 12 is locally reduced, thereby preventing the materials from detaching from the piston when the piston 3 is pulled back without forming fibers. Here, when the piston 3 releases the opening cross-section 21 leading to the supply device 2, space is created for new material 10.

[0158] Temperature sensor 36 on piston bottom 35 measures temperature T at the contact point between piston 3 and materials 10, 11. K This allows for the calculation of the cooling and heating power of the printhead 100, ensuring that it does not exceed the glass transition temperature T of the material 10. g Since the temperature sensor 36, or temperature contact, is located on the bottom 35 of the piston, it is possible to adjust the heating elements 61 and 63 in relation to the piston position, thereby setting the temperature T. S This allows for faster heating of materials 11 and 12. Therefore, the thermal management of the printhead 100 also enables the processing of plastics with low melting temperatures of less than 60°C to 80°C.

[0159] During the compression process used to establish the liquid phase 12 of material in process zone E, nozzle 8 is closed. Nozzle 8 can be closed, for example, by a shut-off valve (not shown) or by positioning the printhead 100 onto a plate in the structural space of the printer. Alternatively, it can be moved to the already printed area of ​​component 9 and thereby close nozzle 8. During the compression process, nozzle needle 32 sinks into and moves further into the melting chamber 81, thereby squeezing a portion of the liquid phase 12 from melting zone D back into mixing zone C, whereby the liquid phase 12 mixes with the plastic phase 11 from plasticizing zone B. Here, the liquid phase 12 from melting zone D is squeezed from the upper region of melting chamber 81 through the opening 71 of kidney-shaped member 7 back into the cavity 40 of piston sleeve 4 and enters mixing zone C.

[0160] Figure 4 A schematic illustration of a printhead 100 according to the invention is shown, the printhead having a control and adjustment unit 113 and an evaluation unit 114, the control and adjustment unit being used to actively adjust the actuator device 110 to move the piston 3, and the evaluation unit being configured to evaluate the measurements of sensors 36, 82, 83, 111, 112 and transmit the results to the control and adjustment unit 113 for actively adjusting the actuator device 110 and for actively adjusting the heating elements 61, 63.

[0161] The control and adjustment unit 113 is configured to actively adjust the actuator device 110 to move the piston 3 for filling and printing according to the operating strategy to be implemented, and is configured to actively adjust the temperature of the first heating element 61 and the second heating element 63.

[0162] For the active adjustment actuator device 110, the decisive factors are the sensor signals received by the evaluation unit 114 and the results calculated from the corresponding values.

[0163] Used for pressure p L Pressure sensor 83 and temperature T for liquid phase 12 L Temperature sensor 82 is arranged in melting chamber 81. A displacement measuring system 111 for the position s of piston 3 and a hydraulic pressure p for the force F applied by piston 3 to materials 10, 11 or applied to piston 3 are arranged on actuator device 110 or on piston 3. H Sensor 112. Furthermore, a temperature T for the plastic phase 11 of the material is arranged on the piston 3. K Temperature sensor 36.

[0164] The signals s, F, and p of sensors 111, 112, 36, 82, and 83, as indicated by the dashed arrows, represent these signals. H T K T L pL The result is passed to the evaluation unit 114, where it is evaluated or in the cloud, and the result is passed to the control and regulation unit 113 as a control parameter i according to the operation strategy, and the actuator device 110 and the heating elements 61, 63 are manipulated accordingly.

[0165] Figure 5 A flowchart illustrating a method 200 for operating a printhead 100 according to the present invention is shown, wherein method 200 includes the following steps:

[0166] -The cavity 40 of 210 is filled with printable material 10 by the supply device 2.

[0167] -The opening cross section 21 of the piston sleeve 4 is closed by the piston 3 being fed from the starting position 3a toward the nozzle 8 of the print head 100.

[0168] - The material is transformed from solid phase 10 to liquid phase 12 via plastic phase 11.

[0169] -Compress 240 material 10, 11, 12,

[0170] - Determine the spring constant for liquid phase 12 at 250°C.

[0171] -Prepare for printing of liquid phase 12 260.

[0172] - A liquid phase of 270g of material is output from nozzle 8 for printing three-dimensional components 9.

[0173] - Move piston 3 back to the starting position 3a at 280 degrees, and

[0174] - Repeat steps 210 through 280 in step 290 until step 200 ends.

[0175] At least the closure 220, conversion 230, compression 240, spring constant determination 250, printing preparation 260, and output 270 of method 200 are performed by active adjustment of actuator device 110 by control and adjustment unit 113, wherein the results obtained by evaluation unit 114 from the measurement values ​​of sensors 36, 82, 83, 111, 112 are transmitted to control and adjustment unit 113.

[0176] The method steps will be described in more detail below.

[0177] Figure 6 A partial view and two curves of the printhead 100 according to the present invention are shown. Figure 6 a, 6b, the graphs show the pressure or force direction during operation, or during different method steps of the method 200 for operating the printhead 100. Figure 7 Piston 3 is shown in Figure 6 The different positions of the different method steps or states, starting from the initial position 3a and ending at the final position 3z of the piston bottom 35. During the implementation of the method steps, the cooling devices 50, 33 and the heating elements 61, 63 in the flange 5 and piston 3 are active, and the melting chamber 81 and the kidney-shaped part 7 are filled with melt 12, and there is also particulate material in the plastic phase 11 in the lower part of the cavity 40.

[0178] The portion of the printhead 100 shown corresponds to the area in Figure 1 , 3 The printhead 100 according to the invention shown in Figure 4 is such that the reference numerals in the previous figures are taken as illustrative purposes. Figure 6 and 7 , among which, Figure 6 and 7 New features and references are marked, such as the corresponding position of piston 3 relative to piston bottom 35.

[0179] Figure 6 First curve Figure 6 Figure a shows two curves plotted along the stroke s traversed by piston 3. Stroke s is measured by a displacement measuring system 111, or displacement sensor 111, on actuator device 110 or on piston 3. The upper curve shows the force F applied by piston 3 to materials 10, 11, or the hydraulic pressure p applied to piston 3 during feeding via actuator device 110 during closing 220 and compression 240. H The force direction and pressure direction are determined by the force or pressure sensor 112, which is arranged on the actuator device 110 or on the piston 3.

[0180] curve Figure 6 The lower curve in a shows the melt pressure p in the melting chamber 81 during the stroke s of piston 3 during compression 240. L The pressure direction. The pressure p used for liquid phase 12, or melt 12. L The pressure sensor 83 is arranged in the melting chamber 81.

[0181] Second curve Figure 6 The first curve is shown in b. Figure 6 The lower part of the curve of a shows the melt pressure p in the melting chamber 81 during the stroke s of piston 3 during compression 240. L The direction of pressure (from p) c to p d (The curve's direction).

[0182] Figure 7Figure 3a shows the initial position 3a of piston 3 during the filling process 210 of printhead 100, wherein the piston bottom 35 is positioned on the upper side of the opening 21 of piston sleeve 4. The entire process from filling 210 to nozzle opening 820 during print preparation 260 is also called the refill process because it involves a recurring process that is arbitrarily repeated during the printing of component 9. The piston 3's position... Figure 7 The location shown in a is similar to Figure 1 The position of piston 3. The opening 21, or the opening cross-section 21, of piston sleeve 4 is open, and particulate material 10 can be introduced into the cavity 40 of piston sleeve 4 via supply device 2. Subsequently, piston 3 is controlled to the position by actuator device 110. Figure 7 In position 3b shown in Figure b, the piston bottom 35 slides past the cut 44 of the piston sleeve 4, and the particulate material 10 protruding from the opening 21 into the cavity 40 is sheared between the piston bottom 35 and the cut 44. Therefore, this position is called shear position 3b. After shearing 420, the opening cross section 21 is closed 220.

[0183] Force and pressure tend to move towards F and p H Ascending from the initial position 3a to the shearing position 3b, the force consumption of the actuator device 110 is highest at the cut 44, or at the shearing position 3b, because the actuator device 110 must apply a force to shear the particulate material 10. This force consumption can be reduced through appropriate measures, such as optimizing the cut geometry in conjunction with the characteristics of the piston bottom 35 and the preheating of the particulate material 10. Conversely, the pressure of the melt 12 flows towards p. L The change is only slight, or almost negligible, because nozzle 8 remains open and no pressure is built up in melting chamber 81.

[0184] The compression process 240 then begins, and piston 3 moves to position 3c under force or pressure control via actuator device 110. During piston 3 displacement, the force F applied to the material, or particulate material 10, 11, or the hydraulic pressure p applied to piston 3 is measured. H And measuring the pressure p in melt 12 L Materials 10, 11, and 12 are pre-compressed by shifting piston 3.

[0185] Position 3c is defined by increasing force or pressure; that is, position 3c is manipulated, but not directly manipulated on the curve. Figure 6 The curve shown in a is not a point, but a side (Flanke). The side is the point p where the curve rises from a straight line with a low, or rather, small slope (the region from position 3a to position 3c) to a point p where the curve rises (at position 3c). Lc F c pHc A predetermined slope or angle of inclination is formed at this location. Position 3c is located in the first third of the plasticizing zone B. In the plasticizing zone B, the particulate materials 10 and 11 are compressed by the feed of the piston 3, while simultaneously in the melting zone D, there is a melt 12 between the cavity 40 and the nozzle 8. The plasticized particulate material 11 is thus extruded into the melt 12 in the mixing zone C.

[0186] By lowering piston 3 and similarly piston needle 32 toward nozzle 8, melt 12 has exited nozzle 8, thereby expelling any remaining air or air inclusions from nozzle head 6. This empties nozzle 8.

[0187] Position 3c is subject to tolerances depending on the method and materials, and thus, the position 3c of piston 3 can be slightly different in different, successive refilling processes of printhead 100. Therefore, position 3c is not a fixed point. If position 3c is within a pre-defined tolerance, the filling process 210 is guaranteed to be successful, i.e., sufficient particulate material 10 has been filled into cavity 40 and melting chamber 81 has been filled with melt 12. If the side begins, for example, too far before position 3c, there may be too much highly viscous or hard material 10, 11 in the region from piston bottom 35 to nozzle 8, and the mixing process in mixing zone C may be unsuccessful. If the side begins, for example, far after position 3c, too little material 10 may be refilled.

[0188] After reaching position 3c, the pre-compression ends 610, and the nozzle 8 of the printhead 100 is closed 620.

[0189] To compress 630, piston 3 is pressure-controlled fed from position 3c until a predefined peak pressure p is reached. d And the piston bottom 35 has moved to... Figure 7 Position 3d as shown in c. Peak pressure p depends on material 10 and requirements. d It can be located between approximately 100 and 300 bar.

[0190] Subsequently, the so-called peak pressure position 3d is maintained for a predefined time period related to the material. Here, the piston bottom 35 extends into the first heating zone 65, and the piston needle 32 extends into the melting chamber 81. During this holding period, a portion of the melt 12 flows from the melting chamber 81 of the nozzle head 6 back into the mixing zone C through the opening 71 of the kidney-shaped member 7, entering the plastic granular material 10 located there. This displaces residual air, and the melt 12 is homogenized in the mixing zone C. This results in better energy flow and the production of more uniform materials 11 and 12. The returning melt 12 becomes plastic, and the portion of granular material 11 pushed into the kidney-shaped member 7 becomes molten. This results in the mixing of materials 11 and 12.

[0191] Furthermore, the holding process 640 described herein is used for analysis and system checks of the printhead 100, because at pressure p L The pressure measurement produces the following effect: the pressure p in melt 12 L The increase in pressure means that melt 12 releases gas, because, for example, the temperature T L Too high. The melting temperature T is too high. L It is undesirable because it would generate air plasma, which would lead to chemical decomposition.

[0192] Melt pressure p L A strong pressure drop could mean, for example, that the system of printhead 100 is not sealed or that there is too much air in the system. This effect can occur, for example, when there is too much cold material 10, 11 in the cavity 40 because the temperature management of printhead 100 is not optimally set.

[0193] After the predefined time period ends, piston 3 is moved back to 710 by actuator device 110 from peak pressure position 3d under pressure control until the target pressure p is reached at approximately 0 bar. e The system is unloaded. This results in melt 12 being pressure-unloaded and vented, thereby producing pure melt 12, particularly in process zone E, which is now of high quality and printable. Upon reaching the target pressure p... e At that time, to reach Figure 7 The target pressure position 3e shown in d is such that the piston bottom 35 is located outside the first heating zone 65 in the area of ​​the stop 43 of the piston sleeve 4.

[0194] The pressure p at the peak pressure location 3d is currently being measured. d Pressure p at target pressure position 3e e The pressure difference between the two points and the travel distance s between the two points 3d and 3e yields the spring constant 740 of the liquid phase 12 or melt 12 of the material.

[0195] The spring constant is generated by the compressibility of the melt 12 and results in a correction factor or shape factor, which is required to precisely control the piston 3 via the actuator device 110.

[0196] Due to the compressibility of melt 12, geometrically, 1.2 volume units of the piston stroke s through piston 3 correspond, for example, to 1.0 volume unit of the volume of melt 12 discharged. In the absence of compressibility, this ratio is 1:1.

[0197] This enables the actuator device 110 to adjustably control the piston 3, wherein the spring constant is particularly effective in ensuring that the actual discharge of the melt 12 is based on the trajectory velocity v of the print head 100 moving during printing. B To achieve the correct, calculated volumetric flow of melt 12. That is, at each printing position, at each trajectory velocity v of the print head 100. B In this case, the required amount of melt 12 will be output to component 9.

[0198] Subsequently, the process of preparing 260 to output 270 of melt 12, or printing process 270, is carried out by actively decompressing 810 by pulling back piston 3.

[0199] Here, piston 3 is pulled back by about 1 to 2 millimeters according to the determined spring constant, thereby ensuring that if the nozzle 820, or nozzle opening, is subsequently opened, no melt 12 exits from nozzle 8 or nozzle opening. This will be the case when the position 3e is maintained, due to the influence of gravity on the existing open system. Meanwhile, melt 12 is unloaded similarly to a spring.

[0200] Subsequently, further printing preparation begins via compression 830. As already described, the entire system of printhead 100 is a compressible system because the melt 12 is capable of compression, for example, approximately 20%. Therefore, the volume expelled by the feed of piston 3 does not correspond to the volume of material 12 discharged, resulting in inaccurate and uneven discharge. The possible volume of melt 12 (its feed for printing process 270) is determined by the target position 3e and... Figure 7 The journey is limited to the final position 3z shown in e.

[0201] Due to the effects described above, the melt 12 is compressed during the start of printing. The compression of the melt 12 in the melting chamber 81 at the start of printing is partly caused by friction at the nozzle opening of the nozzle 8 when the melt 12 is "extruded", and partly caused by resistance when printing onto the component 9 or substrate carrier, on which the component 9 is constructed.

[0202] Uniform discharge of the melt 12 is achieved through intelligent adjustment of the printhead 100, wherein the asynchronous movement of the piston 3 is adapted with a correction coefficient by using an electronic drive on the actuator device 110. Specifically, the correction coefficient, derived from the spring constant 740 of the melt 12, is incorporated into the system. Therefore, the printhead 100 according to the invention does not have the limitation on synchronous movement as common NC systems.

[0203] The printing process 270 is performed under pressure regulation, wherein the pressure p of the melt 12 is continuously measured by the pressure sensor 83 in the nozzle head 6. L The measured pressure p L The pressure is generated by discharging the melt 12 onto the component 9 or the substrate carrier (if no component exists). Without this effect of printing onto an object, there is no corresponding pressure on the nozzle 8 except for frictional pressure, thus excessive material / melt 12 is discharged from the nozzle 8.

[0204] The printing process 270 begins by actively mixing in the melt 12 through intelligent adjustment and control of the piston 3. Here, a "more" stroke is performed to compensate for the compressibility of the melt 12. In principle, excessive melt 12 is expelled from the nozzle 8; however, pressure is read in parallel with the mixing of the melt 12 by the pressure sensor 83, allowing for corresponding adjustments based on the pressure.

[0205] The electrically driven actuator device 110 has proven to be dynamic and highly effective for this situation.

[0206] The melting temperature T was continuously measured during the printing process 270. S Furthermore, in heating zone 2, melt 12 is regulated to the required rated value of process temperature in the region of process zone E via heating element 63 in nozzle head 6.

[0207] At the start of printing, piston 3 moves at a speed v according to the trajectory of printhead 100. B The molten metal 12 is discharged from the nozzle 8 by the actuator device 110.

[0208] During the printing process 270, the control and adjustment unit 113 of the printhead 100 is activated and actively intervenes in the operation of the actuator device 110 to, for example, mix the added rated values ​​s when needed. aK Or, in other words, the amount of material 12 added. If, for example, it is mixed with the added nominal value s... aK And thus, more material 12 is discharged or extruded from nozzle 8 compared to continuous operation, resulting in a higher pressure p on nozzle head 6. L Also increased. The added rating saK This is the value that is mixed in, or rather, the additional piston stroke that must be traversed, so that the desired volume of melt 12 is discharged according to the correction value obtained from the spring constant. This achieves a steady-state vibration state, whereby the amount of melt 12 discharged onto member 9 remains constant.

[0209] This process is in Figure 8 The curve is shown as an example in the graph. Figure 8 a shows the stroke-time curve, which has the rated stroke s of piston 3. KS The curve and the added ratings below it. aK The added rating is added or mixed into the rated stroke s due to the active adjustment of piston 3. KS middle.

[0210] Figure 8 b shows the following graph, which depicts the trajectory speed v of the print head 100 during printing. B and the melt pressure p at time t during the pressure process L .

[0211] The trajectory speed v of printhead 100 B The velocity along the trajectory is almost constant up to point v1, and decreases from point v1 to point v2. For example, this is because printhead 100 moves along the curve. From point v2, printhead 100 accelerates again until point v3 and then maintains an almost constant velocity v. B Continue moving. In parallel with this, at... Figure 8 Figure a shows the rated stroke s of piston 3. KS The curve shown here has a constant slope. This curve represents the piston stroke of an unadjusted printhead, where the piston is fed at a constant rate. However, through persistent pressure and temperature measurements, it was determined that the pressure p... L Or, in other words, the melt pressure p L The pressure direction is along the trajectory speed v of the printhead 100. B Changes occur during braking and acceleration (see...) Figure 8 b). From this change, determine the added nominal value S. aK And accordingly, piston 3 is manipulated, wherein the added rated value S aK Added to the rated stroke of piston 3 KS It can be subtracted from or from the middle.

[0212] When the printhead 100 brakes, piston 3 becomes slower (see...). Figure 8 The negative slope s1 in a), or in other words, the piston can even come to a standstill or change its direction of motion. This happens because of the trajectory velocity v. BThe sharp drop reduced the pressure p. L By manipulating or pre-controlling the piston 3, excessive material 12 is prevented from being discharged from the nozzle 8 onto the component 9.

[0213] At trajectory velocity v B At point v2, acceleration begins, initiating the aforementioned compression of melt 12, which necessitates a longer stroke from piston 3 compared to the case of an incompressible medium. Here, control and regulation unit 113 actively intervenes in the system and takes over control. It causes an increase in the rated value s. aK The increase in pressure 12 results in the extrusion of more material 12 and, as a result, the pressure p at nozzle 8. L Increase.

[0214] By feeding the piston 3 and the resulting increase in pressure within the melt 12 (at point p2), the virtual "spring" of the melt 12 becomes smaller or stiffer. This technical effect is compensated and adjusted by the control and adjustment unit 113, thereby ensuring that the precise amount of melt 12 continues to be discharged from the nozzle 8 during the printing process 270, so as to apply, for example, a layer of the same thickness to the component 9.

[0215] When the trajectory velocity v B When constant, a steady-state vibration is achieved, wherein the amount of melt 12 extruded remains constant and the trajectory velocity v of the print head 100 remains constant. B Keep it the same.

[0216] Here, the use of piston pin 32 results in the following advantageous effects: direct volume displacement of the melt 12 within the melting chamber 81 can be achieved through this piston pin, thereby achieving a smaller spring constant. A smaller spring constant, in turn, enables high dynamics of the printhead 100. This effect is achieved by enabling more direct pressure transmission to the melt 12 through piston pin 32. Therefore, during piston 3 feed, not only the piston bottom 35, but also the piston pin 32 positioned closer to the nozzle 8, transmits pressure pulses for discharging the melt 12 from the nozzle 8.

[0217] The printing process 270 can continue until the piston bottom 35 reaches position 3z, where position 3z is determined such that the piston bottom 35 just does not reach the mechanical stop, but rather... Figure 7 As shown in e, it stops shortly before reaching the kidney-shaped part 7. Then, it is no longer possible to discharge material 12, and the refilling process described above restarts.

[0218] exist Figures 9 to 15 In the accompanying drawings, a single flowchart of the method steps of the method 200 according to the invention is shown in addition to the embodiments described in the previous drawings.

[0219] Figure 9 A flowchart is shown for a method of filling cavity 40 210 with printable material 10 via supply device 2, wherein filling 210 includes at least the following steps:

[0220] - The material 10 is fed into the print head 100 through the opening 23 of the supply device 2.

[0221] - Generates 320 air pulses 26 to separate the material 10, especially the granular material blocks 10, from each other.

[0222] The filling 310 of the granular material block 10 is performed manually or automatically, wherein the granular material block 10 slides into the lower region 24 of the supply device 2 due to gravity.

[0223] The generation of air pulses 26 is performed intermittently 320, and the particulate material blocks 10 are thrown up in the area of ​​the air pulses 26, so that when these particulate material blocks fall down, pulses are applied to the particulate material blocks 10 located below them and energize these particulate material blocks to continue sliding into the heated cavity 40 of the printhead 100.

[0224] Figure 10 A flowchart is shown for a method of closing the opening cross-section 21 of the piston sleeve 4 220 via the piston 3, wherein closing 220 includes the following steps:

[0225] - The piston 3 is fed 410, starting from the initial position 3a of the piston bottom 35 towards the nozzle 8 until it reaches the position 3b below the cut 44 of the piston sleeve 4, wherein,

[0226] - By allowing the piston bottom 35 to slide past the cut 44, 420 granular materials 10 are sheared.

[0227] Figure 11 A flowchart is shown for a method of converting material from a solid phase 10 to a liquid phase 12 via a plastic phase 11, wherein the conversion 230 includes the following steps:

[0228] - The heating elements 61 and 63 of the nozzle head 6 heat the materials 10, 11, and 12 in state zones A, B, C, D, and E of the print head 100, wherein state zones A, B, C, D, and E represent the material 10 and its temperature T. S The relevant aggregated states, and by introducing the heating energy of heating elements 61 and 63, the aggregated states of materials 10, 11, and 12 are changed from solid phase 10 to liquid phase 12 via plastic phase 11 in state regions A, B, C, D, and E, and

[0229] - The materials 11 and 12 are mixed during compression 240.

[0230] Figure 12 A flowchart illustrating a method for compressing materials 10, 11, and 12 of material 240 is shown. This compression process 240 includes the following steps:

[0231] -Pre-compress material 10, 11, and 12 of 610 by feeding piston 3.

[0232] -Close 620 nozzle 8,

[0233] - The 630 material 10, 11, 12 are compressed by the feed of piston 3, and

[0234] - Hold piston 3 at 640 in holding position 3d.

[0235] Pre-compression 610 of materials 10, 11, 12 is performed under pressure and / or force control via the feed of piston 3, wherein the pre-compression is performed to position 3c, and the position is reached when the material-related slope and / or the material-related tilt angle of the force curve and / or pressure curve is reached and / or exceeded.

[0236] When nozzle 8 is closed, the compression 630 of materials 10, 11, and 12 is performed in a controlled manner by the feed pressure of piston 3, and then moves to the holding position 3d until the peak pressure p is reached. d Or rather, it should maintain its position through peak pressure p d limited.

[0237] During compression 630, the nozzle 8 is closed, and the piston needle 32 is submerged into the melting chamber 81 of the nozzle head 6, thereby squeezing a portion of the liquid phase 12 from the upper region of the melting chamber 81 through the opening 71 of the kidney-shaped member 7 from the melting zone D back into the mixing zone C, whereby this portion of the liquid phase 12 is mixed with the plastic phase 11 from the plasticizing zone B in the mixing zone C.

[0238] Piston 3 is held in holding position 3d, wherein the pressure p of liquid phase 12 is measured during holding process 640. L and temperature T L The measured values ​​are verified by the evaluation unit 114 to perform a functional check on the compression process 240.

[0239] While the piston 3 is held in the holding position 3d, the nozzle 8 is closed and the piston needle 32 is submerged into the melting chamber 81, thereby squeezing a portion of the liquid phase 12 from the upper region of the melting chamber 81 through the opening 71 of the kidney-shaped member 7 from the melting zone D back into the mixing zone C, whereby this portion of the liquid phase 12 is mixed with the plastic phase 11 from the plasticizing zone B in the mixing zone C.

[0240] Figure 13A flowchart is shown for a method to determine the spring constant of liquid phase 21 at 250°C, wherein determining 250°C includes the following steps:

[0241] - After holding at position 640, move back from holding position 3d to target position 3e under pressure control at position 710, when the melt pressure p L Achieving target pressure p e When the target location is reached,

[0242] - Calculate the peak pressure p d With target pressure p e The pressure difference between them is 720.

[0243] -Calculate the distance 730 between the maintained position 3d and the target position 3e.

[0244] - Calculate the spring constant 740 for liquid phase 12.

[0245] Figure 14 A flowchart is shown for a method of preparing liquid phase 12 for printing 260, wherein printing preparation 260 includes the following steps:

[0246] -Active decompression of liquid phase 12 is achieved by pulling piston 3 back according to the spring constant 810.

[0247] - Open nozzle 820, and

[0248] - Compress liquid phase 12 at the start of printing 830.

[0249] Figure 15 A flowchart is shown for a method for outputting liquid phase 12 270, wherein printing method 270 is performed under pressure regulation, wherein:

[0250] -Persistently measure the pressure p in the 910 melting chamber 81. L The measured pressure p L This is related to the pressure generated by discharging liquid phase 12 onto component 9.

[0251] - The piston 3 of the 920 is actively manipulated by the control and adjustment unit 113, wherein the feed of the piston 3 of the 930 is adapted to the pressure with a correction factor, wherein the correction factor is derived from the spring constant of the liquid phase 12 of the material.

Claims

1. A method (200) for operating a print head (100) of a 3D printer. Its features are, The method (200) includes the following steps: - The cavity (40) is filled (210) with printable material (10) by the supply device (2). - The opening cross section (21) of the piston sleeve (4) is closed (220) by the feed of the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100). - The material is transformed (230) from the solid phase (10) to the liquid phase (12) via the plastic phase (11). - Compress (240) the material (10, 11, 12). - Determine the spring constant of the liquid phase (12) described in (250). - Prepare the liquid phase (12) for printing (260). - The liquid phase (12) of the material is output (270) from the nozzle (8) for printing three-dimensional components (9). - Move the piston (3) back (280) to the starting position (3a), and - Repeat steps (290) from filling (210) to moving back (280) until the method (200) ends. The compression (240) of the materials (10, 11, 12) includes the following steps: - The material (10, 11, 12) is pre-compressed (610) by the feed of the piston (3). - Close (620) the nozzle (8). - The material (10, 11, 12) is compressed (630) by the feed of the piston (3). - Hold the piston (3) (640) in the holding position (3d).

2. The method (200) according to claim 1. Its features are, At least the closure (220), the conversion (230), the compression (240), the determination of the spring constant (250), the printing preparation (260), and the output (270) are performed by active adjustment of the actuator device (110) by the control and regulation unit (113), wherein the results obtained by the evaluation unit (114) from the measurements of the sensors (36, 82, 83, 111, 112) are transmitted to the control and regulation unit (113).

3. The method (200) according to claim 1 or 2. Its features are, The filling (210) of the cavity (40) with printable material (10) by the supply device (2) includes at least the following steps: - The material (10) is filled (310) into the print head (100) through the opening (23) of the supply device (2), and - Generate (320) air pulses (26) to separate the materials (10) from each other, the materials having granular material blocks.

4. The method (200) according to claim 3. Its features are, The filling (310) of the granular material block is performed manually or automatically, wherein the granular material block slides into the lower region (24) of the supply device (2) due to the influence of gravity.

5. The method (200) according to claim 4. Its features are, Intermittently generate air pulses (26) (320) and throw the particulate material block in the area of ​​the air pulses (26) such that when the particulate material block falls, a pulse is applied to the particulate material block below it and the particulate material block is induced to continue sliding into the heated cavity (40) of the print head (100).

6. The method (200) according to claim 1 or 2. Its features are, The closure (220) of the opening cross section (21) of the piston sleeve (4) by the piston (3) includes the following steps: - Feed (410) the piston (3) from the starting position (3a) of the piston bottom (35) of the piston (3) toward the nozzle (8) until reaching the position (3b) below the cut (44) of the piston sleeve (4), wherein, - Shearing of particulate material (420) is achieved by allowing the bottom of the piston (35) to slide past the cut (44).

7. The method (200) according to claim 1 or 2. Its features are, The transformation (230) of the material from the solid phase (10) to the liquid phase (12) via the plastic phase (11) includes the following steps: - The heating elements (61, 63) of the nozzle head (6) heat (510) the material (10, 11, 12) in the state zones (A, B, C, D, E) of the print head (100), wherein the state zones (A, B, C, D, E) represent the material (10, 11, 12) at a temperature T. S The associated aggregated state, and by introducing the heating energy of the heating elements (61, 63), the aggregated state of the materials (10, 11, 12) is changed from the solid phase (10) to the liquid phase (12) via the plastic phase (11) in the state regions (A, B, C, D, E), and - The materials (11, 12) are mixed (520) during the compression (240).

8. The method (200) according to claim 1 or 2. Its features are, The pre-compression (610) of the materials (10, 11, 12) is performed in a pressure and / or force-controlled manner by the feed of the piston (3), wherein the pre-compression is performed to a position (3c) when the material-related slope and / or the material-related tilt angle of the force and / or pressure curve is reached and / or exceeded.

9. The method (200) according to claim 1 or 2. Its features are, With the nozzle (8) closed, the compression (630) of the materials (10, 11, 12) is performed in a pressure-controlled manner by the feed of the piston (3), and then moves to the holding position (3d) until the peak pressure (p) is reached. d ).

10. The method (200) according to claim 1 or 2. Its features are, During the compression (630), the nozzle (8) is closed and the piston needle (32) is submerged into the melting chamber (81) of the nozzle head (6), thereby squeezing a portion of the liquid phase (12) from the upper region of the melting chamber (81) back into the mixing zone (C) through the opening (71) of the kidney-shaped member (7), whereby the portion of the liquid phase (12) is mixed with the plastic phase (11) from the plasticizing zone (B) in the mixing zone (C).

11. The method (200) according to claim 2. Its features are, The piston (3) is held in the holding position (3d), wherein the pressure (p) of the liquid phase (12) is measured during the holding process (640). L ) and temperature (T) L The measured values ​​are verified by the evaluation unit (114) to perform a functional check on the compression process (240).

12. The method (200) according to claim 10. Its features are, During the holding (640) of the piston (3) in the holding position (3d), the nozzle (8) is closed and the piston needle (32) is submerged in the melting chamber (81), thereby squeezing a portion of the liquid phase (12) from the upper region of the melting chamber (81) back into the mixing zone (C) through the opening (71) of the kidney-shaped member (7) from the melting zone (D), thereby mixing the portion of the liquid phase (12) with the plastic phase (11) from the plasticizing zone (B) in the mixing zone (C).

13. The method (200) according to claim 9. Its features are, The determination (250) of the spring constant of the liquid phase (12) includes the following steps: - After the holding (640) ends, the melt is pressure-controlledly moved back (710) from the holding position (3d) toward the target position (3e) when the melt pressure (p L ) to reach the target pressure (p e When the target location is reached, - Calculate the peak pressure (p) d ) and the target pressure (p) e The pressure difference between (720) and (720) is between them. - Calculate the distance (730) between the holding position (3d) and the target position (3e). - Calculate the spring constant (740) of the liquid phase (12).

14. The method (200) according to claim 1 or 2. Its features are, The printing preparation (260) of the liquid phase (12) includes the following steps: - Actively decompress the liquid phase (12) by pulling back the piston (3) according to the spring constant (810). - Open (820) the nozzle (8), and - The liquid phase (12) is compressed (830) at the start of printing.

15. The method (200) according to claim 10. Its features are, The output (270) of the liquid phase (12) is executed under pressure regulation, wherein: - Persistently measure (910) the pressure (p) in the melting chamber (81). L ), - Actively manipulate (920) the piston (3) via control and adjustment unit (113), wherein the feed of the piston (3) is adapted (930) with a correction coefficient in relation to pressure, wherein the correction coefficient is derived from the spring constant of the liquid phase (12) of the material.

16. A print head (100) for a 3D printer, for performing the method (200) according to any one of claims 1 to 15, said print head comprising: An actuator device (110) disposed in the housing (1) of the print head (100) is used to control the piston (3). Supply device (2), the supply device being used for printable material (10). A flange (5) is arranged on the housing (1) and the supply device (2), the flange having a cooling device (50). Nozzle head (6), the nozzle head having heating elements (61, 63) for converting the material (10) from a solid phase (10) via a plastic phase (11) into a liquid phase (12), and Nozzle (8), the nozzle being used to output the liquid phase (12) of the material (10) from the nozzle head (6), The feature is that it is provided with a control and adjustment unit (113), which is used to actively adjust the actuator device (110) to move the piston (3) according to the operating strategy to be implemented, for filling and printing and for actively adjusting the heating elements (61, 63).

17. The printhead (100) according to claim 16. Its features are, The evaluation unit (114) is configured to evaluate the measurements of the sensors (36, 82, 83, 111, 112) of the printhead (100) and transmit the results to the control and adjustment unit (113) to actively adjust the actuator device (110) and the heating elements (61, 63).

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