A method for providing a printable molten material to operate a 3D printer print head, and a 3D printer print head for carrying out this method.

Abstract

A method (200) for providing a printable melt (12) for operating a print head (100) for a 3D printer. According to the invention, the method (200) comprises the steps of filling (210) a hollow space (40) with printable material (10) by means of a feed mechanism (2), closing (220) an open cross-sectional area (21) of a piston bushing (4) by moving a piston (3) from a start position (3a) towards a nozzle (8) of the print head (100), transitioning (230) the material from a solid phase (10) through a plastic phase (11) to a liquid phase (12), compressing (240) the material (10, 11, 12), detecting (250) an elastic constant of the liquid phase (12) and preparing (260) the liquid phase (12) for printing. A print head (100) for a 3D printer for carrying out the method (200) according to the invention.

Description

Technical Field

[0001] The present invention relates to a method for providing a printable melt for operating a print head for a 3D printer and a print head for a 3D printer for implementing this method.

Background Art

[0002] A 3D printer for a material that can vary in terms of viscosity includes the solid phase of this material as a starting material, then generates a liquid phase, and selectively applies this liquid phase to locations belonging to the object to be produced. Such a 3D printer includes a print head that preprocesses the starting material to prepare it for printing. Further, means are provided for generating a relative movement between the print head and the working surface on which the object is produced. At this time, only the print head can be moved, only the working surface can be moved, or both the print head and the working surface can be moved.

[0003] The print head has a first operating state in which the liquid material flows out therefrom and a second operating state in which the liquid material does not flow out therefrom. The second operating state is, for example, the state occupied when approaching another position on the working surface and not depositing material there during the process. Between the two operating states of the print head, for example, it can be switched by turning on and off the thrust of the solid starting material.

[0004] The most widespread is "fused deposition modeling" (FDM; fused deposition modeling). In this method, a filament made of a starting material is melted in an electrically heated extrusion nozzle and applied layer by layer on a platform. In the form of this type of filament, the starting material is very expensive.

[0005] Patent Document 1 proposes supplying the starting material in granular form, transporting it to a heated zone via a conveyor screw, and then discharging it in a plastic form. On the one hand, it is clear that granular form is preferable, and on the other hand, a mixture consisting of various thermoplastic materials can be easily produced in this manner.

[0006] Furthermore, a print head is known from Patent Document 2, in which granules are plastically deformed within the print head via a piston and a heated section. When the piston presses against the granules, the granules are compressed and transported to the plasticization zone in the lower region of the print head. A force is generated at this time, and this force places a strong load on the piston and the cylinder wall of the print head, which can accelerate wear of the cylinder wall of the print head housing. In addition, a complex dissolution geometry with a heat conduction structure is disclosed, in which the heat conduction structure brings the heating force of the heating element into the plasticized material, thereby bringing it into the liquid phase of the material. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2016 / 082627A1 [Patent Document 2] German Patent Application Publication No. 102016222306A1 Specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a method for providing a printable molten material for operating a print head for a 3D printer, and a print head for a 3D printer, wherein the method and print head provide a high-value molten material with reproducible quality. [Means for solving the problem]

[0009] Within the scope of the present invention, a method has been developed for providing a printable molten material to operate a print head for a 3D printer. Furthermore, a print head for a 3D printer for carrying out this method has been developed.

[0010] According to the present invention, the above method includes the following steps. - A step of filling a hollow space, particularly a heatable hollow space, with a printable material using a supply mechanism. - A step of closing the opening cross section of the piston bush by moving the piston from the starting position toward the nozzle of the print head, - A step of transitioning the material from a solid phase to a liquid phase via a plastic phase, - A step of compressing the material, - A step of detecting the elastic constant of the liquid phase, - A step of preparing the liquid phase for printing.

[0011] In a further configuration of the present invention, at least the steps of closing, transferring, compressing, detecting the elastic constant, and preparing for printing are performed by active control of the actuator device by a control and adjustment unit, in which case the results of the evaluation unit based on the sensor measurements are transmitted to the control and adjustment unit.

[0012] The entire process from filling the print head nozzles during print preparation is also called the refilling process, because this entire process is an iterative process that can be arbitrarily repeated while printing a part. The refilling process is a method of providing printable molten material to operate the print head of a 3D printer.

[0013] Furthermore, the present invention relates to a print head for a 3D printer for carrying out the method according to the present invention. The print head includes an actuator device for controlling a piston, located within a housing of the print head; a supply mechanism for printable material; a flange located in the housing and the supply mechanism and equipped with a cooling device; a nozzle head equipped with a heating element for transferring the material from a solid phase through a plastic phase to a liquid phase; and a nozzle for discharging the liquid phase of the material from the nozzle head, in which case, according to the present invention, a control and adjustment unit is provided for active control of the actuator device for driving the piston in accordance with the operating strategy to be carried out for filling and printing, and for active control of the heating element.

[0014] In a further configuration of the printhead, an evaluation unit is provided to evaluate the printhead sensor measurements and transfer the results to a control and adjustment unit for active control of the actuator device and for active control of the heating element. The evaluation unit may be implemented separately from the control and adjustment unit, or it may be integrated into it.

[0015] By detecting and evaluating sensor values ​​based on the operating state at each stage, the functionality of the print head can be checked, which is advantageous as it allows for the early identification of errors or deviations in the process. Furthermore, by detecting sensor values, a defined target value can be controlled. It is also possible to calculate a correction coefficient and send it to the control and adjustment unit. For example, by adding the correction coefficient to the target value, it is advantageous to achieve the release of a desired fixed amount of molten material from the nozzle. Active control of the heating element enables dynamic temperature control, which in turn favorably influences both heating and cooling. For example, if the heating energy of the first heating element is reduced by the control and adjustment unit, cooling within the flange continues, and this cooling extracts energy from the plastic phase of the material, causing it to cool rapidly. Furthermore, active control of the actuator device and heating element allows material to be ejected from the nozzle as needed, in which case different orbital velocities of the print head can be compensated for by the actively controlled material volume.

[0016] Therefore, active control offers advantages over conventional NC systems, namely, it always releases the same volume regardless of its orbital velocity, or it offers advantages over conventional NC systems that control the release amount at a constant feed rate without actively controlling this process.

[0017] The actuator device for controlling the piston may be, for example, an electric motor with a mechanical transmission, or a hydraulic drive device with a hydraulic source. Electric motors, as actuator devices, are lighter than hydraulic drive systems, which is advantageous because they only need to accelerate a small mass, thus enabling high dynamics in the entire printer and the printing process. Hydraulic drive systems are advantageous because they can achieve a large force when controlling a piston.

[0018] The supply mechanism for printable materials may be provided in particular as a supply unit for materials or starting materials that exist in granular form. The starting materials may be thermoplastic materials in particular. It was found that using granules as a starting material offers unique advantages compared to printheads that use filaments made of thermoplastic materials, particularly in terms of the cost of the printer's starting materials.

[0019] Compared to printheads that use a conveyor screw to transport granules, the printhead according to the present invention can be configured more compactly. This also results in the printhead being easier and simpler to move. This is particularly advantageous when the printhead needs to be moved at very high speeds, especially at speeds of 100 mm / s or more.

[0020] The flange includes a cooling device, which is advantageous because it provides optimized thermal management in the area of ​​the feeder, thereby avoiding material or granule adhesion at the piston. Furthermore, the nozzle head has a heating element for transferring solid-phase material, particularly granules, to the liquid phase. The heating element within the nozzle head is advantageous because it serves to effectively transfer heating force to the material to be melted. Subsequently, the liquid phase or molten material can be discharged through the nozzle of the nozzle head by piston motion.

[0021] The piston bushing is implemented as a separate component for guiding the piston, allowing the piston to be guided directly within the piston bushing and not within the printhead housing or cylinder. This is advantageous because wear does not occur directly on the inner walls of the housing or cylinder, but rather within the piston bushing. The piston bushing as a separate component offers the advantage of being replaceable when necessary. In addition, it provides the possibility of using pistons and piston bushings that are compatible with each other, even if they have different diameters, without further structural modifications, for example, in the flange and nozzle head.

[0022] In a further configuration of this method, the step of filling a hollow space, particularly a heatable hollow space, with a printable material using a supply mechanism includes at least the following steps: - A step of filling the print head with material or granular mass through the opening of the supply mechanism, - A step of generating an air impulse to separate multiple granular clumps from each other, It includes.

[0023] In a further configuration, the step of filling the granular mass is performed manually or automatically, in which case the granular mass is slid into the lower region of the supply mechanism by the effect of gravity.

[0024] In a more advantageous configuration of the filling step, the step of generating air impulses is performed intermittently, and the granular clumps are tossed up in the region of the air impulses, that is, as the granular clumps fall again, impulses are applied to the granular clumps below them, causing them to slide sequentially into the heated hollow space of the print head.

[0025] An effective refilling process requires a back-blow of the granules, which creates a lifting effect, causing the granules to then slide into the print head. Throwing or winding is necessary for automatic charging, as the resulting gravity impulse or impact is advantageous as it causes the granules to slide in sequentially. If necessary, an air impulse can be used to dislodge any stuck granules, which is advantageous as it avoids print head downtime.

[0026] In a further configuration of this method, the step of closing the open cross-section of the piston bush with the piston includes the following steps: - The step of advancing the piston from the starting position of the piston bottom toward the nozzle until it reaches a position below the notch of the piston bush, and in this case, - The step of shearing the granules by sliding the bottom of the piston near the notch, It includes.

[0027] The piston bush has an upper portion that protrudes into the flange and a lower portion that protrudes into the nozzle head. This is advantageous because the upper portion is positioned within the operating range of the cooling zone of the flange cooling device, and the lower portion is positioned within the operating range of the heating zone of the nozzle head, thereby achieving effective energy dissipation from the material within the cooling zone or effective energy supply to the material within the heating zone. The upper portion of the piston bush has an opening or opening cross section that allows material to be supplied into the piston bush from the supply device. The lower portion of the opening has a notch formed at an obtuse angle to the inner surface of the piston bush. The notch area is hardened, or alternatively, implemented as a separate hardened insert. When the opening is closed by the piston, the material or granules are sheared by the piston in the notch, thereby acting a strong mechanical load on this portion of the piston bush. The separate piston bush and the hardened notch area are advantageous because they achieve a longer lifespan and faster replacement of defective parts.

[0028] In a further configuration of this method, the step of transitioning the material from a solid phase to a liquid phase via a plastic phase includes the following steps: - A step of heating the material by the heating element of the nozzle head across the state zone of the print head, in which case the state zone is the temperature T of the material. S The cohesive state of the material depends on the following: The heating step involves changing the cohesive state of the material from a solid phase through a plastic phase to a liquid phase across state zones by applying heating energy from a heating element. -A step of mixing the materials during the compression step, It includes.

[0029] The print head has different state zones starting from the upper part of the piston bushing, passing through the kidney-shaped member, and extending to the nozzle. In this case, the state zones are determined by the material temperature T SThis represents the aggregation state of the material, which depends on [something]. In this case, the aggregation state of the material can change from a solid phase to a plastic phase and then to a liquid phase across state zones. It is advantageous for the printhead state zone to include a low-temperature zone containing solid-phase material, a plasticization zone containing plastic-phase material, a melting zone and a process zone containing liquid-phase material, respectively, and a mixed zone containing material in both plastic and liquid phases. Furthermore, even in this case, the cooling device within the flange and the piston cooling unit integrated within the piston are related to the temperature T of the plastic phase of the material in the plastic deformation zone. S Glass transition temperature T g It is provided to maintain the temperature below (the temperature at which the material undergoes plastic deformation and transitions to the liquid phase).

[0030] This is advantageous because it means that the piston bottom is in contact exclusively with the solid phase of the material and not with the fully plasticized phase. The fully plasticized phase has a highly viscous, sticky consistency with a strong tendency towards surface adhesion. Therefore, if the piston comes into contact with this phase, it may adhere to it, which makes it difficult for fresh granules to flow sequentially, for example, when the piston is pulled back. This effect is avoided, which is advantageous.

[0031] To implement this method, the nozzle head includes two heating zones. Within the first heating zone, there are a partial region of the plasticization zone, a mixing zone, and a partial region of the melting zone. In this case, the first heating element is positioned within the upper nozzle head as follows: that is, heating energy is introduced from the first heating element into the material through the lower partial region of the piston bush, the kidney-shaped member, and the section of the upper nozzle head. Within the second heating zone, a portion of the melting zone and a process zone are arranged, in which case the second heating element is positioned within the lower nozzle head as follows, namely, so that heating energy can be introduced from the second heating element into the liquid phase of the material via the lower nozzle head.

[0032] Placing both heating zones within the nozzle head contributes to more effective printhead thermal management. This is because the first heating zone serves to favorably pre-plasticize the material without causing it to transition to the liquid phase. This is advantageous because it prevents the piston from seizing during compression, ensuring the printhead functions flawlessly. This effect is optimized in cooperation with the cooling system within the flange. Furthermore, the material in the plastic phase is pre-plasticized so that the actuator requires less force consumption during piston movement, which is advantageous because it allows the use of a smaller actuator for piston movement. This reduces equipment costs and printhead weight, thus improving printhead dynamics. This allows the printhead to accelerate and decelerate more effectively to generate parts during so-called trajectory control. In the second heating zone, a molten material is generated, and the heating energy supplied is designed to maintain a relatively constant molten material temperature throughout the molten material space. The molten material temperature can be controlled within the second heating zone to prevent the material from being overheated. This is advantageous because it avoids the generation of decomposition products due to excessive heat load, and, firstly, it avoids the generation of gases that would promote further decomposition of the material due to the dominant pressure in the system, directly negatively impacting its quality.

[0033] The compression and transfer processes are performed largely simultaneously, as heating energy is introduced into the print head through both heating zones between the two processes.

[0034] In an advantageous further configuration of the present invention, the step of compressing the material during the compression process includes the following steps: - A step of pre-compressing the material by advancing a piston, - The step of closing the nozzle, - The step of compressing the material by advancing a piston, - The step of holding the piston in the retaining position, It includes.

[0035] In a further configuration of the compression process, the step of pre-compressing the material is carried out while controlling the pressure and / or force by the feed of a piston, in which case pre-compression is performed to the position reached when the material-dependent gradient and / or gradient angle of the force curve and / or pressure curve is reached, and / or exceeds.

[0036] In the next method step, the material is compressed while controlling the pressure by advancing a piston with the nozzle closed, aiming to reach a holding position until the peak pressure is reached.

[0037] In a further configuration, the nozzle is closed during the compression step, and the piston needle is submerged in the molten space of the nozzle head, so that a portion of the liquid phase is removed from the upper region of the molten space through the opening of the kidney-shaped member and returned from the molten zone to the mixing zone, thereby mixing the portion of the liquid phase with the plastic phase coming from the plasticization zone in the mixing zone.

[0038] In a further configuration, the piston is held in a holding position, and during this holding process, the pressure and temperature of the liquid phase are measured. These measurements are then checked by an evaluation unit to manage the function of the compression process.

[0039] Furthermore, in a further configuration, the nozzle is closed during the step of holding the piston in the holding position, and the piston needle is submerged in the molten space as follows: that is, submerged in the molten space so that a portion of the liquid phase is returned and removed from the upper region of the molten space through the opening of the kidney-shaped member from the molten zone to the mixing zone, thereby mixing the portion of the liquid phase with the plastic phase coming from the plasticization zone in the mixing zone.

[0040] The pre-compression step is carried out by controlling the piston with an actuator device while controlling the force or pressure, in which case the target position of the piston bottom is at the first third of the plasticization zone, starting from the low-temperature zone. The granules are compressed by the piston feed in the plasticization zone, and at the same time, there is molten material between the hollow space and the nozzle in the molten zone. As a result, the plasticized granules are pressurized into the molten material in the mixing zone. Lowering the piston and correspondingly lowering the piston needle toward the nozzle is advantageous because it allows the molten material to exit the nozzle, thereby expelling any air or trapped air from the nozzle head. This frees up the nozzle.

[0041] After the pre-compression step reaches the target position, the print head nozzles are closed.

[0042] To compress the material, the piston is advanced by an actuator device while the pressure is controlled until a predetermined peak pressure is reached, and thus until the peak pressure position is reached. In a further configuration of this method, the nozzle is closed in order to operate the print head during the compression step, and the piston needle is submerged in the molten space as follows: that is, it is submerged in the molten space so that a portion of the liquid phase is returned and removed from the upper region of the molten space through the opening of the kidney-shaped member from the molten zone to the mixing zone, thereby mixing the portion of the liquid phase with the plastic phase coming from the plasticization zone in the mixing zone.

[0043] Subsequently, the so-called peak pressure position is maintained for a predetermined time, which depends on the material, and therefore the peak pressure position is also the position where the print head is held. In a further configuration of this method, the nozzle is closed while the piston is held in the holding position, and the piston needle is submerged in the molten space as follows: that is, submerged in the molten space so that a portion of the liquid phase is returned and removed from the upper region of the molten space through the opening of the kidney-shaped member from the molten zone to the mixing zone, thereby mixing the portion of the liquid phase with the plastic phase coming from the plasticization zone in the mixing zone.

[0044] The holding process removes residual air and homogenizes the molten material in mixing zone C. This is advantageous because it achieves a more favorable energy flow and produces a homogeneous material. The returning molten material becomes plastic, and the granular components pushed into the kidney-shaped member become molten. This results in material mixing. In addition, the holding process described here is advantageous because it can be used for printhead analysis and system checks, because the following effects can occur during pressure measurement: A pressure increase within the molten material suggests, for example, that the molten material is releasing gas due to its excessively high temperature. Excessively high molten material temperatures are undesirable because they can lead to the formation of air plasma, which is thought to cause chemical decomposition. A strong pressure drop in the molten material pressure suggests, for example, that the printhead system was not sealed or that there was still an excess of air in the system. This effect is thought to occur when, for example, an excess of cold material was present in the hollow space due to insufficient temperature control of the printhead.

[0045] In a further configuration, the step of detecting the elastic constant of the liquid phase includes the following steps: - After the holding step is completed, the vehicle is moved back from the holding position to a target position achieved when the molten material pressure reaches the target pressure, while controlling the pressure. - A step of detecting the pressure difference between the peak pressure and the target pressure, - A step of detecting the distance between the holding position and the target position, - A step to calculate the elastic constant of the liquid phase, It includes.

[0046] The elastic constant is derived from the compressibility of the molten material and is used to derive correction factors or shape factors necessary for precise control of the piston by the actuator device. Based on the compressibility of the molten material, for example, 1.2 volume units of the geometric piston distance advanced by the piston corresponds to 1.0 volume unit of the molten material discharged. Without compressibility, a ratio of 1:1 can be considered.

[0047] Detecting the elastic constant of the molten material is advantageous because it allows the actuator device to be controlled while adjusting the piston, in which case the elastic constant enables the achievement of an accurate calculated volume flow of molten material, where the actual amount of molten material released depends on the orbital velocity of the print head moving during printing. That is, regardless of the orbital velocity of the print head, the required amount of molten material is released onto the part at each printing position.

[0048] In a further configuration, the step of preparing the liquid phase for printing includes the following steps: - A step of actively reducing the pressure of the liquid phase by pulling back the piston depending on the elastic constant, - The step of opening the nozzle, It includes.

[0049] When actively reducing pressure, the piston is pulled back by approximately 1 to 2 millimeters, depending on the detected elastic constant. This is advantageous because it prevents molten material from flowing out of the nozzle or nozzle opening even if it opens. This is likely due to the influence of gravity, as the existing system is an open system, and its position remains constant. Simultaneously, the molten material is unloaded like a spring.

[0050] Next, by continuing the print preparation, the printing process begins through compression. The entire printhead system is a compressible system, as the molten material can have, for example, approximately 20% compression. Therefore, the volume removed by the piston feed does not correspond to the volume of material being released, which can result in inaccurate and irregular release.

[0051] The release of the liquid phase, i.e., printing, is carried out while controlling the pressure, in this case, - Continuously measure the pressure within the molten material space. - The piston is actively controlled via a control and adjustment unit, in which case the piston feed is adjusted according to a pressure-dependent correction coefficient, the correction coefficient being obtained from the calculated elastic constant of the liquid phase of the material.

[0052] The measured pressure corresponds to the pressure caused by the release of the liquid phase into the component, and the correction factor is advantageous for compensating for the compressibility of the liquid phase.

[0053] The compression of the molten material within the molten material space at the start of printing is generated partly through friction at the nozzle opening of the nozzle when "extruding" the molten material, and partly through resistance when printing on the component or substrate support (on which the component is assembled). Uniform discharge of the molten material is achieved by intelligent control of the print head, and in this case, the asynchronous motion of the piston, which is adapted by a correction factor, is performed by using an electronic transmission device in the actuator. In particular, the correction factor obtained from the elastic constant of the detected molten material is merged into the system, so to speak. Therefore, the method according to the present invention is advantageous because it is not limited to synchronous motion like in a normal NC system.

[0054] Electrically driven actuator devices have proven to be dynamic and highly effective in this case.

[0055] Furthermore, several advantages can be obtained from the printhead configuration, in which case the piston bush may have a stopper between the upper and lower portions, and the stopper separates the flange and the nozzle head from each other. Thus, the piston bush and especially the stopper are advantageous because they separate the cooled flange from the heated nozzle head, thereby preventing them from coming into contact with each other. Furthermore, a kidney-shaped member may be positioned in the lower region of the piston bush, in which case the kidney-shaped member has a concentrically extending perforation for receiving the piston needle of the piston.

[0056] The printhead piston includes a first piston portion for coupling with an actuator device and a piston head coupled to the first piston portion and for receiving a piston needle. The first piston portion is advantageously formed as a hollow aluminum piston, which allows the first piston portion to guide a coolant, thereby achieving piston cooling. The piston head has a lower surface on the nozzle side, in which case the piston needle protrudes from the center of this lower surface. The surface of the lower surface of the piston head, excluding the imaginary surface of the piston needle, forms a piston surface for generating pressure on the material. The lower surface of the piston head is cooled together with the piston cooling, which locally reduces the viscosity of the molten or plastic material at the bottom of the piston. This is advantageous because it prevents liquid molten material from flowing towards the drive device, thereby preventing the piston from sticking in the piston bush and preventing molten material from entering the drive device. In addition, the material detaches more easily from the bottom of the piston or the underside of the piston head during the retraction phase, and as a result, when the piston reaches its starting point or outward position, the remaining material does not adhere to the bottom of the piston, making it possible to easily refill with solid-phase material or granules. Advantageously, a temperature sensor is mounted on the underside or bottom of the piston head. This placement allows for temperature control of the print head depending on the piston position, thereby achieving faster heating of the material without the molten material coming into contact with the underside of the piston head. This is advantageous because it allows for an acceleration of the print head filling process. The piston head is implemented as a cylindrical component and is advantageously manufactured from a heat-resistant material. A combination in which the first piston portion is implemented from aluminum and the piston head is implemented from, for example, steel has been proven advantageous. This is because, in this configuration, the piston has an elastic upper region for absorbing mechanical stress and a heat-resistant region provided in the region of the material being heated. Depending on the piston's position, the piston needle may either partially protrude into the perforation of the kidney-shaped member or penetrate entirely through it, which is advantageous because it guides the piston needle within the central perforation of the kidney-shaped member.

[0057] The kidney-shaped member has multiple concentrically arranged openings, in which case these openings form a fluid coupling between the hollow space located within the piston bush and the molten material space located within the lower portion of the nozzle head.

[0058] The hollow space is located inside the piston bushing and is formed by a volume portion whose outer surface is formed by the inner surface of the piston bushing, the outer surface of the piston needle, the upper surface of the kidney-shaped member, and the lower surface of the piston. Within the hollow space, the material or granules are compressed by the movement of the piston through the underside of the piston head or the piston surface. During the compression of the material, the temperature control of the print head is set so that no liquid phase or molten material is formed within the hollow space, and the material is formed as a plastic phase. This is advantageous because it prevents the plasticized material from adhering to the underside of the piston. However, during compression, a portion of the liquid phase or molten material in the molten space is pushed from the molten space into the hollow space of the piston bushing through multiple concentrically arranged openings in the kidney-shaped member by a piston needle that enters the molten space. At this time, a portion of the molten material mixes with a portion of the plastic phase. This is advantageous because the molten material releases energy into the plastic phase, thereby generating a homogeneous material. Therefore, the kidney-shaped member forms a mixer or static mixer, which is advantageous because, other than the piston movement, no other moving parts are needed to mix the plastic phase with the liquid phase. Therefore, the kidney-shaped member configuration is advantageous because it serves a blending action that more favorably mixes the material or molten material with the plasticizing material. The kidney-shaped member is advantageous because it guides the heating energy from the heating element in the nozzle head to both the molten material and the piston needle, thereby improving energy management when heating the molten material.

[0059] The kidney-shaped member may be formed as a separate component, or it may be formed integrally with the piston bush.

[0060] Furthermore, within the molten space, the pressure p of the liquid phase L Pressure sensor and / or temperature sensor for T L A temperature sensor is positioned for this purpose. Pressure p L The measurement of temperature T is a first-order parameter that also determines the discharge, release, or mass flow of molten material from the outlet. LAuxiliary measurements make it possible to take into account the temperature dependence of the viscosity of the material when determining the mass flow Q. By means of piston feed, the amount to be dispensed can be accurately adjusted. Moreover, for the quality of the parts or objects to be manufactured, temperature T in a particular form of precise control is more important in order to avoid thermal degradation of the material. L Control of is more important. In addition, the actuator device and / or the piston are provided with a distance measurement system for the position s of the piston, and / or a sensor for the force F acting from the piston on the material or the hydraulic pressure p acting on the piston. H A sensor for is provided. The feed of the piston is a reference for the amount of material to be discharged. This amount can be controlled, inter alia, via the distance measurement system. Furthermore, the force F is directly correlated with the pressure in the material. Furthermore, the piston, particularly on the lower surface of the piston head of the piston, has a temperature sensor for the temperature T of the plastic phase of the material. K A temperature sensor for is arranged. This arrangement of the temperature sensor enables heat management depending on the piston position of the print head, whereby more rapid heating of the material is achieved without the melt coming into contact with the lower surface of the piston head. This is advantageous as it enables acceleration of the filling process of the print head or reduction of the required time for the filling process.

[0061] Next, further measures for improving the present invention will be presented in more detail together with an explanation of advantageous embodiments of the present invention based on the figures.

Brief Description of the Drawings

[0062] [Figure 1] It is a view of a print head according to the present invention. [Figure 2] It is another view of a print head according to the present invention. [Figure 3] It is a view of one section of a print head according to the present invention. [Figure 4] It is a schematic view of a print head according to the present invention. [Figure 5] This is a flowchart of the method according to the present invention for providing a printable molten material. [Figure 6] This diagram shows one section of the print head according to the present invention as the pressure changes over time. [Figure 7] This figure shows different positions of the piston in the print head according to the present invention. [Figure 8] This is a flowchart of a method for filling the hollow space in the print head. [Figure 9] This is a flowchart of a method for closing the opening cross-section of the print head piston bushing. [Figure 10] This is a flowchart illustrating a method for transitioning a material from a solid phase to a liquid phase via a plastic phase. [Figure 11] This is a flowchart of a method for compressing a material. [Figure 12] This is a flowchart of a method for detecting the elastic constant of the liquid phase of a material. [Figure 13] This is a flowchart showing the method for preparing the liquid phase of the material for printing. [Modes for carrying out the invention]

[0063] Figure 1 shows a print head 100 for a 3D printer, which includes an actuator device 110 for controlling a piston 3, located within a housing 1 of the print head 100; a supply mechanism 2 for printable material 10; a flange 5 located in the housing 1 and the supply mechanism 2, equipped with a cooling device 50; a nozzle head 6 equipped with heating elements 61, 63 for transferring the material 10 from a solid phase 10 through a plastic phase 11 to a liquid phase 12; and a nozzle 8 for discharging the liquid phase 12 of the material 10 from the nozzle head 6. The print head 100 includes a separate piston bush 4 to guide the piston 3.

[0064] The flange 5, which is internally cooled by the cooling device 50, serves to thermally isolate the lower heating region of the print head 100 from the actuator device 110 or from the drive unit of the piston 3.

[0065] The piston 3 includes a first piston portion 31 for mounting the piston 3 to the actuator device 110, and a piston head 34 fixed to the first piston portion 31 and receiving a piston needle 32 in the direction of the nozzle 8. The piston 3, or the lower surface 35 of the piston head 34, has a temperature T of the plastic phase 11 of the material. K A temperature sensor 36 is positioned to measure the temperature. The lower surface 35 of the piston head 34 forms the piston bottom 35. The first piston portion 31 is preferably formed as an aluminum hollow piston, in which case the aluminum hollow piston has a hollow space which is formed inside as a cooling passage. At the lower end of the first piston portion 31 is a piston cooling section 33 which is cooled via a refrigerant system. The piston cooling section 33 serves to harden the materials 11,12 at the piston bottom 35, thereby sealing the piston 3 in the direction of the actuator device 110, or thereby preventing the flow of fluid molten material 12 in the direction of the actuator device 110. A coolant is preferably used as the refrigerant, in which case the coolant is transported through the housing 1 via a plurality of connections and a flexible tube into the cooling connection section 37 of the first piston portion 31. The cooling device 50 inside the flange 5 is supplied with refrigerant by the same refrigerant system.

[0066] Cooling of materials 11 and 12 at the piston bottom 35 locally reduces the viscosity of materials 11 and 12, causing the material to separate from the piston without forming a string when the piston 3 is pulled back. At this time, a space is formed for new material 10.

[0067] Figure 1 shows the piston 3 in the starting position for filling the print head 100 with printable material 10 supplied into the print head 100 via the supply mechanism 2.

[0068] The supply mechanism 2 is formed in a hopper shape, in which case the material 10, which is advantageously granular, is filled into the opening of the supply mechanism 2 from above. The material 10 reaches the opening 21 or the cross section of the opening to the piston bush 4 by gravity. An air passage 20 is located in the lower region of the supply mechanism 2 above the opening 21. The air passage is subjected to air impulses by a pneumatic valve 22. The pneumatic valve 22 and the air passage 20 form a blowing device, that is, the blowing device intermittently applies an air blast to the granules so that the granules 10 are thrown towards a region further up in the supply mechanism 2, thereby causing the individual granule clumps 10 to dissociate from one another. When the airflow is cut off, the granules 10 in the lower region of the supply mechanism 2 fall into the piston bush 4 as the cross section 21 opens. This prevents the granule mass 10 from sticking to the injection device of the supply mechanism 2, thereby preventing clogging of the supply device 2, and ensuring that the injection device reliably fills the piston bush 4 with the granules 10. Furthermore, a small diameter section may be used at the inlet of the supply mechanism 2. The refilling process requires back-blowing of the granules 10, which creates a lifting effect on the granules, causing them to slide into the print head 100. Winding is necessary for automatic charging, and the resulting gravitational impulses or impacts cause the granules 10 to slide in sequentially.

[0069] The piston bush 4 has an upper portion 41 that protrudes into the flange 5 and a lower portion 42 that protrudes into the upper portion 60 of the nozzle head 6. A stopper 43 is positioned between the upper portion 41 and the lower portion 42 of the piston bush 4, separating the flange 5 and the nozzle head 6 from each other. The opening 21 or opening cross section is located within the upper portion 41 of the piston bush 4 and has a notch 44 on its inner surface. The notch 44 causes the granules 10 to be sheared between the notch 44 and the piston bottom 35 until the piston bottom 35 reaches a position below the notch 44 when the opening cross section 21 is closed by the piston 3.

[0070] The piston bush 4 has an obtuse angle in the notch 44, in which case the obtuse angle has a sharp edge and is hardened. Local hardening is advantageous in this case. In an alternative embodiment, the notch 44 may be formed by a separate insert member such as a throwaway tip. The structure of the notch 44 is advantageous because it reduces the force required to shear the granules 10, thereby saving energy and reducing the likelihood of wear on the piston bush 4 and piston 3. However, the edges of the notch 44 are extremely prone to wear.

[0071] The lower portion region 42 of the piston bush 4 contains a kidney-shaped member. (Intermediate member) A 7 is positioned, in which case the kidney-shaped member 7 has a perforation 70 extending to the center to receive the piston needle 32 of the piston 3. The kidney-shaped member 7 further has a plurality of concentrically arranged openings 71, which form a fluid coupling between a hollow space 40 located within the piston bush 4 and a molten material space 81 located within the lower portion 62 of the nozzle head 6. The hollow space 40 is located inside the piston bush 4 and is formed by the inner surface of the piston bush 4, the outer surface of the piston needle 32, the upper surface of the kidney-shaped member 7, and the lower surface 35 of the piston 3.

[0072] The main challenge of the kidney-shaped member 7 is heat conduction or energy transfer from the heating elements 61, 63 of the nozzle head 6 to the liquid phase 12 of the material or molten material 12. This is achieved, in particular, by increasing the contact area with respect to the hollow space 40 and therefore with respect to the plastic phase 11 of the material. A further challenge is guiding the piston needle 32, in which case contact of the piston needle 32 inside the borehole 70 serves to assist in heating the piston needle 32 to the required process temperature. The final process temperature is first achieved within the nozzle head 6 as it moves toward the nozzle 8.

[0073] During the filling process of the print head 100, the nozzle 8 is closed when necessary, and when the piston 3 is controlled by the actuator device 110, the materials 10, 11, and 12 located in the hollow space 40 and the molten space 81 are compressed by the piston feed.

[0074] The nozzle head 6 includes heating elements 61 and 63 of the print head 100, in which case the first heating element 61 is located in the upper nozzle head 60 and the second heating element 63 is located in the lower nozzle head 62. The upper nozzle head 60 has a section 64, which is located between the upper nozzle head 60 and the lower nozzle head 62, and a kidney-shaped member 7 is placed on this section. In the nozzle 8 area, a cooling ring 84 is located on the nozzle head 6. The cooling ring cools the part to be printed and thermally shields this part from the print head 100.

[0075] The heating elements 61 and 63 within the nozzle head 6 heat the inside of the hollow space 40, the inside of the kidney-shaped member 7, and the molten space until the liquid phase 12 of the material reaches its process temperature and can be released from the nozzle 8. 81 Heat the materials 10, 11, and 12 inside the molten space. 81 The upper nozzle head 60 is formed to taper from section 64 to the nozzle 8. The conical supply section of the molten material space 81 allows for the rise of the volumetric flow and prevents material from settling on the inner wall of the nozzle head 6. The mixing process is further optimized because the conical shape of the molten material space 81 has less material 12 or volume compared to when the molten material space 81 is cylindrical. This reduces the volume that the piston needle 32 has to remove to return some of the molten material 12 from the molten material space 81 to the hollow space 40 through the opening 71 of the kidney-shaped member 7 during sealing.

[0076] Furthermore, the print head 100 includes other sensors, in which case the pressure p of the liquid phase 12 of the material is detected within the molten space 81. L Pressure sensor 83 for use, and temperature T LA temperature sensor 82 is positioned for this purpose. Other sensors are located in the actuator device 110, in this case a distance measuring system 111 for the position s of the piston 3 and a distance measuring system 111 for the force F acting from the piston 3 to the materials 10,11 or the hydraulic pressure P acting on the piston 3. H A sensor 112 for use is provided. In an alternative embodiment, sensors 111 and 112 may also be located on the piston 3 of the print head 100.

[0077] Figure 2 is another diagram of the print head 100 according to the present invention, in which case, according to the present invention, the solid phase 10 of the material contains granular aggregates 10, and the supply mechanism 2 has a blowing device 25 for separating a plurality of granular aggregates 10 from each other. The blowing device 25 includes a pneumatic valve 22 and an air passage 20, in which case the air passage 20 is located within the housing portion 27 of the supply mechanism 2 and opens above the opening cross-sectional portion 21 of the flange 5 in the lower region 24 of the supply mechanism 2. The air passage 20 can be subjected to the action of an air impulse 26 by the pneumatic valve 22, in which case the air impulse 26 acts on the granular masses in the lower region 24 so that the multiple granular masses 10 dissociate from one another. The supply mechanism 2 is formed in a hopper shape, in which case the granular mass 10 is filled into the opening 23 of the supply mechanism 2 from above. The material 10 reaches the opening cross section 21 of the flange 5, or the piston bush 4, or the opening cross section 21 of the piston bush 4 by gravity. An air passage 20 of the blowing device 25 is located in the lower region 24 of the supply mechanism 2 above the opening cross section 21 of the flange 5. The air passage 20 is subjected to an air impulse 26 by a pneumatic valve 22. The blowing device 25 includes the pneumatic valve 22 and the air passage 20, in which case the granules 10 are thrown in the direction of the area of ​​the supply mechanism 2 further above, and are intermittently subjected to an air blast so that the individual granular masses 10 dissociate from each other. When the blowing device 25 is turned off, the granules 10 in the lower region 24 of the supply mechanism 2 fall into the hollow space 40 of the piston bush 4 when the opening cross section 21 opens. As a result, the blowing device 25 of the supply mechanism 2 prevents the granule clumps 10 from sticking, thereby preventing clogging of the supply device 2, and ensuring that the blowing device reliably fills the piston bush 4 with granules 10. The refilling process requires back-blowing of the granules 10, which creates a lifting effect on the granules, causing them to slide into the print head 100. Winding is necessary for automatic charging, and the resulting gravity impulse or impact causes the granules 10 to slide in sequentially.

[0078] Figure 3 shows one section of the print head 100 according to the present invention rotated 90°, illustrating the state zones A, B, C, D, and E of the print head 100, which are filled with materials 10, 11, and 12 during operation, starting from the upper portion region 41 of the piston bush 4, passing through the kidney-shaped member 7, and extending to the nozzle 8. State zones A, B, C, D, and E correspond to the temperature T of the material 10. S This represents the aggregation state which depends on the state, and in this case, the aggregation state of material 10 throughout state zones A, B, C, D, and E is changeable from solid phase 10 to liquid phase 12 via plastic phase 11.

[0079] Temperature T of materials 10, 11, and 12 inside print head 100 SAlternatively, the temperature progression is shown in the graph above the print head 100, in which case the temperature T S The diagram is illustrated with respect to distance s or the length of the working range 120 of the print head 100.

[0080] The state zones A, B, C, D, and E of the printhead 100 include a low-temperature zone A where the material is in solid phase 10, a plasticization zone B where the material is in plastic phase 11, and a molten zone D and a process zone E where the material is in liquid phase 12, respectively. Furthermore, the state zones include a mixed zone C where the material is in plastic phase 11 and liquid phase 12.

[0081] The cooling device 50 inside the flange 5 and the piston cooling unit 33 integrated inside the piston 3 are at the temperature T of the plastic phase 11 of the material in the plasticization zone B. S The glass transition temperature T is the starting point at which material 11 undergoes plastic deformation and transitions to the liquid phase 12. g The following is provided for retention. The plasticization zone B, in which the material is in the plastic phase 11, describes a state of material or granules in which the viscosity of the granules has already changed, thereby optimizing the compression and mixing process, however the plastic phase 11 of the granules has not yet transitioned to the liquid phase 12.

[0082] Furthermore, the nozzle head 6 includes two heating zones 65 and 66. Within the first heating zone 65, there is a partial region of the plasticization zone B, a mixing zone C, and a partial region of the melting zone D. In this case, the first heating element 61 is positioned within the upper nozzle head 60 as follows: that is, heating energy is introduced from the first heating element 61 into the materials 10, 11, and 12 via the lower partial region of the piston bush 42, the kidney-shaped member 7, and the section 64 of the upper nozzle head. Within the second heating zone 66, a portion of the melting zone D and a process zone E are arranged, in which case the second heating element 63 is positioned within the lower nozzle head 62 as follows, that is, so 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.

[0083] As can be seen from the graph, the temperature T of materials 10, 11, and 12 S The temperature rises continuously with respect to the distance s of the working range 120 of the print head 100. In the low-temperature zone A, the action of the cooling device 50 of the flange 5 is dominant, so that the granules 10 are heated only slowly over distance s. From the plasticization zone B onward, the influence of the first heating element 61 in the first heating zone 65 becomes larger, and in this case the temperature curve rises to the glass transition temperature T g The temperature rises sharply until it reaches [temperature T], and from there the mixed zone C begins. S In the mixing zone C, the temperature rises further with a smaller gradient until it reaches the melting zone D. Then, the influence zone as the second heating zone 66 by the second heating element 63 begins, in which case the second heating element raises the temperature of the melt 12 until the process temperature of the melt 12 is achieved in the process zone E, producing a printable melt 12. S It can significantly increase the value.

[0084] temperature T S The following adjustments must be made: that the granules 10 flow into the hollow space 40 without adhering during filling, but that the shearing of the materials 10 and 11 in section 44 is possible with the least possible force consumption. In this case, the temperature control of the print head 100 is adjusted as follows: that the cooling device 50 in the flange 5 brings the piston bush 4 into which the materials 10 and 11 are cooled to approximately 40°C, and the first heating element 61 of the first heating zone 65 brings the glass transition temperature T of the materials 10, 11, and 12 to which the glass transition temperature T g Alternatively, it is adjusted to produce a heating temperature of approximately 30°C, below the molten material temperature. This effect is supported by the piston cooling section 33. Cooling of the materials 11 and 12 at the piston bottom 35 locally reduces the viscosity of the materials 11 and 12, thereby allowing the material to separate from the piston without stringing when the piston 3 is pulled back. At that time, when the piston 3 opens its open cross section 21 to the supply mechanism 2, space is provided for new material 10.

[0085] A temperature sensor 36 located at the bottom 35 of the piston detects the temperature T at the point where the piston 3 contacts the materials 10 and 11. K By measuring this, the cooling and heating capacity of the print head 100 can be calculated, and as a result, the glass transition temperature T of material 10 can be determined. g It does not exceed. Since a temperature sensor 36 or temperature detector is located at the bottom 35 of the piston, it is possible to control the heating elements 61 and 63 depending on the piston position, thereby raising the temperature T S The temperature can be adjusted. This allows for faster heating of materials 11 and 12. Therefore, temperature control of the print head 100 also enables processing of plastics at low melting temperatures of 60°C or 80°C or below.

[0086] While the compression process is underway in process zone E to form the liquid phase 12 of the material, the nozzle 8 is closed. The nozzle 8 can be closed, for example, by a shut-off valve (not shown), or by positioning the print head 100 relative to the plate in the build chamber of the printer. Alternatively, the nozzle 8 can be closed by bringing an already printed area of ​​part 9 closer. During the compression process, the piston needle 32 is submerged in the molten space 81 and further enters it, thereby removing multiple portions of the liquid phase 12 from the molten zone D into the mixing zone C, where the liquid phase 12 is mixed with the plastic phase 11 coming from the plasticization zone B.

[0087] At that time, the liquid phase 12 coming from the molten zone D is returned to the mixing zone C and removed from the upper region of the molten space 81 through the opening 71 of the kidney-shaped member 7 into the hollow space 40 of the piston bush 4.

[0088] Figure 4 is a schematic diagram of a print head 100 according to the present invention, which includes a control and adjustment unit 113 for actively controlling the actuator device 110 to move the piston 3, and an evaluation unit 114 formed to evaluate the measured values ​​of sensors 36, 82, 83, 111, and 112, and transfer the results to the control and adjustment unit 113 to actively control the actuator device 110 and the heating elements 61 and 63. The control and adjustment unit 113 is provided to actively control the actuator device 110 for moving the piston 3 in accordance with the operating strategy to be implemented for filling and printing, and is also provided to actively control the temperatures of the first heating element 61 and the second heating element 63. The key to actively controlling the actuator device 110 lies in the sensor signals received by the evaluation unit 114, and the results calculated from their respective values. Pressure p of liquid phase 12 L Pressure sensor 83 for and temperature T L A temperature sensor 82 is located within the molten material space 81. A distance measuring system 111 measures the position s of the piston 3 and the force F acting from the piston 3 to the materials 10,11 or the hydraulic pressure p acting on the piston 3. H The sensor 112 for this purpose is located on the actuator device 110 or the piston 3. Furthermore, the piston 3 has a temperature T of the plastic phase 11 of the material. K A temperature sensor 36 is positioned for this purpose.

[0089] The dashed arrows illustrate the signals s, F, and p from sensors 111, 112, 36, 82, and 83. H ,T K ,T L ,p LThe data is sent to the evaluation unit 114, where it is evaluated either within the unit or in the cloud. The results are then sent to the control / adjustment unit 113 as a control variable i corresponding to the operating strategy, and the actuator device 110 and heating elements 61 and 63 are controlled accordingly.

[0090] Figure 5 is a flowchart of a method 200 according to the present invention for providing a printable molten material 12 for operating a print head 100 according to the present invention, in which case method 200 includes the following steps. - Step 210: Fill the hollow space 40 with printable material 10 by the supply mechanism 2. - Step 220 closes the opening cross section 21 of the piston bush 4 by moving the piston 3 from the starting position 3a towards the nozzle 8 of the print head 100. - Step 230, which involves transitioning the material from the solid phase 10 to the liquid phase 12 via the plastic phase 11. - Step 240: Compress materials 10, 11, and 12. - Step 250 to detect the elastic constant of the liquid phase 12, - Step 260: Prepare liquid phase 12 for printing.

[0091] At least the closing step 220, the transfer step 230, the compression step 240, the elastic constant detection step 250, and the print preparation step 260 of method 200 are carried out by active control of the actuator device 110 by the control and adjustment unit 113, in which case the results of the evaluation unit 114 based on the measurements of sensors 36, 82, 83, 111, 112 are transmitted to the control and adjustment unit 113. Next, we will explain these method steps in more detail.

[0092] Figure 6 shows one section of the print head 100 according to the present invention and two graphs 6a, 6b, the two graphs representing the pressure course or pressure, force course while providing the printable molten material 12 or while performing various method steps of the method 200 for providing the printable molten material. Figure 7 shows the different positions of the piston 3 in the various method steps or states shown in Figure 6, starting from the starting position 3a of the piston bottom 35 and ending at the final position 3z. While performing the method steps, the cooling devices 50, 33 in the flange 5 and the piston 3 and heating elements 61, 63 are operating, the molten material space 81 and the kidney-shaped member 7 are filled with molten material 12, and granules still exist in the plastic phase 11 in the lower portion region of the hollow space 40.

[0093] The illustrated sections of the printhead 100 correspond to those of the printhead 100 according to the present invention illustrated in Figures 1, 3, and 4, and consequently the reference numerals of the previous figures are used to illustrate Figures 6 and 7, in which case new constituent elements and related matters, such as the position of the piston 3 at any given time, are characterized in relation to the piston bottom 35 in Figures 6 and 7.

[0094] Figure 6 shows two curve shapes in the first graph 6a, and these curve shapes are plotted with respect to the distance s advanced by the piston 3. The distance s is measured by a distance measuring system 111 or distance sensor 111 provided on the actuator device 110 or piston 3. The curve above represents the force F acting from the piston 3 to the materials 10,11 during the feeding of the piston 3 by the actuator device 110 during the closing step 220 or the compressing step 240, or the hydraulic pressure p acting on the piston 3. H This indicates the progression of force or pressure, in which case the force sensor or pressure sensor 112 is located on the actuator device 110 or piston 3. The lower curve in Graph 6a represents the molten pressure p in the molten space 81 during the compression step 240. LThis shows the relationship between the pressure progression and the distance s of the piston 3. The pressure p of the liquid phase 12 or molten material 12. L The pressure sensor 83 for this purpose is located within the molten material space 81.

[0095] The second graph 6b illustrates a portion of the curve shown below the first graph 6a, where the molten pressure p in the molten space 81 during the compression step 240 is shown. L The relationship between the pressure progression and the distance s of piston 3 is shown in the diagram (p c from p d (Curved shape).

[0096] Figure 7a shows the starting position 3a of the piston 3 during the filling process 210 of the print head 100, in which case the piston bottom 35 is positioned on the upper surface of the opening 21 of the piston bush 4. The entire process from the filling step 210 to the nozzle opening step 820 during the print preparation step 260 is also called the refilling process, because this process is an iterative process that can be arbitrarily repeated while printing the part 9. The refilling process is a method for providing printable molten material 12 to operate the print head 100 for the 3D printer. The position of the piston 3 shown in Figure 7a corresponds to the position of the piston 3 in Figure 1. The opening 21 or opening cross section 21 of the piston bush 4 is open, and granules 10 can be brought into the hollow space 40 of the piston bush 4 via the supply mechanism 2. Next, the piston 3 is controlled by the actuator device 110 to the position 3b shown in Figure 7b. At this time, the piston base 35 slides near the notch 44 of the piston bush 4, and the granules 10 protruding from the opening 21 into the hollow space 40 are sheared between the piston base 35 and the notch 44. Therefore, this position is called the shear position 3b. After the shearing step 420, the opening cross section 21 is closed 220. Course of force, course of pressure F,p HThe granules rise from the starting position 3a to the shearing position 3b, and in this case the actuator device 110 must provide the force to shear the granules 10, so the force consumption of the actuator device 110 is maximum at the notch 44 or the shearing position 3b. The force consumption can be reduced by appropriate measures such as optimizing the geometric shape of the notch in relation to the characteristics of the piston bottom 35 and the preheating of the granules 10. In contrast, the elapsed pressure of the molten material 12 p L The change is slight, or hardly increases at all. This is because the nozzle 8 is still open, and no pressure increase occurs within the molten space 81.

[0097] Next, the compression process 240 begins, and the piston 3 travels to position 3c, controlled by force or pressure from the actuator device 110. As the piston 3 is displaced, a force F acts on the material or granules 10,11 or a hydraulic pressure p acts on the piston 3. H and pressure p within the molten material 12 L The following is measured. As piston 3 is displaced, materials 10, 11, and 12 are pre-compressed.

[0098] Position 3c is defined by an increase in force or pressure, i.e., position 3c is controlled, in this case not by a direct point, but by the slope of the curve illustrated in graph 6a. The slope is defined by the alternating point p from each straight line (ranging from position 3a to position 3c) with a small gradient or no gradient to the rise of the curve (at position 3c) where it reaches and / or exceeds a predetermined gradient or predetermined gradient angle. Lc ,F c ,p Hc This occurs at position 3c, which is located in the first third of the plasticization zone B. The granules 10 and 11 are compressed by the feed of the piston 3 in the plasticization zone B, and at the same time, in the melting zone D, there is molten material 12 between the hollow space 40 and the nozzle 8. As a result, the plasticized granules 11 are pressurized into the molten material 12 in the mixing zone C. By lowering the piston 3 and correspondingly lowering the piston needle 32 toward the nozzle 8, the molten material 12 is released from the nozzle 8, which in turn allows any air or trapped air to be expelled from the nozzle head 6. This frees up the nozzle 8.

[0099] Position 3c is given tolerances due to the method and material, so that when various refilling processes of the print head 100 are performed sequentially, the position 3c of the piston 3 may differ slightly. Therefore, position 3c is not a fixed point. If position 3c is within a predetermined tolerance range, it is guaranteed that the filling step 210 has been successful, that is, that the granules 10 have sufficiently filled the hollow space 40 and the molten space 81 has already been filled with molten material 12. If the slope starts, for example, far ahead of position 3c, there will be an excess of highly viscous or hard material 10,11 in the area from the piston bottom 35 to the nozzle 8, and in some cases the mixing process in the mixing zone C will not have been successful. If the slope starts, for example, far behind position 3c, in some cases too little material 10 may have been refilled.

[0100] After reaching position 3c, the pre-compression step 610 is completed, and the nozzle 8 of the print head 100 is closed 620.

[0101] To perform step 630 of compression, a predefined peak pressure p d The piston 3 is displaced from position 3c by pressure control until it reaches the peak pressure p and the piston bottom 35 moves to position 3d shown in Figure 7c. d Depending on the material 10 and as needed, it may be between approximately 100 bar and 300 bar.

[0102] Next, the so-called peak pressure position 3d is held for a predetermined time, depending on the material. During this time, the piston bottom 35 protrudes into the first heating zone 65, and the piston needle 32 protrudes into the molten space 81. While held, a portion of the molten material 12 flows back from the molten space 81 of the nozzle head 6 through the opening 71 of the kidney-shaped member 7 into the mixing zone C, and thus into the plastic granules 10 present there. This eliminates residual air, and the molten material 12 is homogenized within the mixing zone C. This results in a better energy flow and the creation of more homogeneous materials 11 and 12. The flowing molten material 12 becomes plastic, and the granular components 11 pushed into the kidney-shaped member 7 become molten. This results in the mixing of materials 11 and 12. The holding process 640 described here is also used for the analysis and system check of the print head 100. This is because the pressure p L This is because the following effects can occur when measuring the pressure: pressure p in the molten material 12 L The pressure increase is, for example, due to temperature T L This likely means that the molten material 12 is emitting gas because the temperature of the molten material T is too high. L The temperature being too high is undesirable because it can generate air plasma, which is thought to cause chemical decomposition. Molten material pressure p L The strong pressure drop suggests, for example, that the printhead 100 system was not sealed or that there was still an excess of air in the system. Such an effect is thought to occur, for example, when the temperature control of the printhead 100 was not optimally adjusted, resulting in an excess of cold material 10,11 being present in the hollow space 40.

[0103] After the aforementioned predetermined time has elapsed, the target pressure p is approximately 0 bar. eUntil the target pressure p is achieved, the piston 3 is returned from the peak pressure position 3d by the actuator device 110 while controlling the pressure 710. The system enters a release state. This achieves the decompression and degassing of the molten material 12, which in turn generates pure molten material 12, particularly in process zone E, and which is of high quality and printable at this point. e When this is reached, the target pressure position 3e shown in Figure 7d is achieved, in which case the piston bottom 35 is positioned outside the first heating zone 65 and within the area of ​​the piston bush 4 stopper 43. At this point, the pressure p at peak pressure position 3d is measured. d and pressure p at target pressure position 3e e The pressure difference and the distance s traveled between points 3d and 3e reveal the elastic constant 740 of the liquid phase 12 or molten material 12.

[0104] The elastic constant is obtained from the compressibility of the molten material 12 and derives a correction coefficient or shape coefficient necessary for the precise control of the piston 3 by the actuator device 110. Based on the compressibility of the molten material 12, for example, 1.2 volume units of the geometric piston distance s advanced by the piston 3 corresponds to 1.0 volume unit of the discharged volume of the molten material 12. Without a compressibility factor, a ratio of 1:1 can be considered.

[0105] This enables the actuator device 110 to be controlled while adjusting the piston 3, in which case the elastic constant is, in particular, the actual amount of molten material 12 released, and the orbital velocity v of the print head 100 that moves during printing. B This enables the accurate calculation of the volume flow of the molten material 12, which depends on the orbital velocity v of the print head 100. B Regardless of the value, the required amount of molten material 12 is released onto the part 9 at each printing position.

[0106] Next, step 810 prepares for a process 270 or printing process 270 to release the molten material 12 via an active depressurization step 810 by pulling back the piston 3. At that time, the piston 3 is pulled back by approximately 1 to 2 millimeters, depending on the detected elastic constant, thereby ensuring that the molten material 12 does not flow out of the nozzle 8 or nozzle opening 820 when it is opened. This is considered to be an example of the effect of gravity, as the existing system is an open system, if position 3e is maintained. Simultaneously, the molten material 12 is unloaded like a spring.

[0107] Next, the further preparation for printing through compression begins. The entire system of the print head 100 is a compressible system, as already mentioned, since the molten material 12 can have, for example, approximately 20% compression. Therefore, the volume removed by the feed of the piston 3 does not correspond to the volume of material 12 released, which can result in inaccurate and irregular release. The possible volume of molten material 12 for the feed of the printing process is defined by the distance from the target position 3e to the final position 3z shown in Figure 7e. Based on the above-described action, the molten material 12 is compressed during the start of printing. The compression of the molten material 12 within the molten material space 81 at the start of printing is partially generated through friction at the nozzle opening of the nozzle 8 when "extruding" the molten material 12, and partially generated through resistance when printing on the component 9 or the substrate support (on which the component 9 is assembled). The uniform discharge of the molten material 12 is achieved by the intelligent control of the print head 100, in which case the asynchronous motion of the piston 3, which is fitted only by a correction factor, is performed by using an electronic transmission device in the actuator device 110. In particular, the correction factor obtained from the elastic constant 740 of the detected molten material 12 is merged into the system, so to speak. Therefore, the print head 100 according to the present invention is not subject to the limitations on synchronous motion that exist in conventional NC systems.

[0108] In this process, the printing process is carried out under controlled pressure, in which case the pressure p of the molten material 12 is L The measured pressure p is continuously measured via a pressure sensor 83 in the nozzle head 6. LThis is the pressure generated by releasing the molten material 12 onto the component 9 or the substrate support (if there is no component yet). Without this action of printing on the object, the nozzle 8 would have no pressure resistance other than frictional pressure, which would cause an excess of material / molten material 12 to be released from the nozzle 8. To start the printing process, the molten material 12 is actively mixed in by the intelligent control and regulation of the piston 3. At this time, "more" strokes are performed to compensate for the compression ratio of the molten material 12. In principle, this would result in an excess amount of molten material 12 being pushed out from the nozzle 8, however, the pressure sensor 83 is read in parallel with the mixing of the molten material 12, allowing for corresponding pressure-dependent control. If the actuator device 110 is electrically driven, it has been demonstrated to be dynamic and highly effective in this case.

[0109] During the printing process 270, the molten material temperature T S The temperature is continuously measured, and in heating zone 2, the molten material 12 is adjusted to the target processing temperature required in the process zone E region via the heating element 63 in the nozzle head 6.

[0110] At the start of printing, the piston 3 is controlled by the actuator device 110 in accordance with the orbital speed of the print head 100, thereby causing the molten material 12 to be discharged from the nozzle 8. During the printing process, the control and adjustment unit 113 of the print head 100 is activated to actively intervene in the control of the actuator device 110, for example, by adding an additional target value or amount of material 12 as needed. For example, by adding an additional target value, thereby releasing or extruding more material 12 from the nozzle 8 than would be possible with continuous control, the pressure p at the nozzle head 6 is increased. LThe pressure also increases. At this time, the additional target value is the mixing value, or the additional piston distance that must be covered to release a desired volume of molten material 12, corresponding to the correction value obtained from the elastic constant 740. This achieves a steady state, thereby maintaining a constant amount of molten material 12 released onto the part 9.

[0111] In this process, the use of the piston needle 32 has the advantageous effect of enabling direct volume displacement within the molten material 12 in the molten material space 81, thereby achieving a smaller elastic constant. A smaller elastic constant also enables high dynamics of the print head 100. This effect is obtained as a result of the more direct pressure transmission to the molten material 12 by the piston needle 32. Therefore, when the piston 3 is advanced, not only the piston bottom 35 but also the piston needle 32, which is positioned closer to the nozzle 8, transmits pressure impulses to discharge the molten material 12 from the nozzle 8.

[0112] The printing process can be carried out until the piston bottom 35 reaches position 3z, in which case position 3z is set so that the piston bottom 35 stops just before reaching the kidney-shaped member 7, as shown in Figure 7e, rather than reaching the mechanical stopper. Thereafter, the material 12 is no longer released, and the refilling process according to the present invention described above is restarted.

[0113] Figures 8 to 13 illustrate individual flowcharts of the method steps of Method 200 according to the present invention, complementing the embodiments of the present invention described in the above figures.

[0114] Figure 8 is a flowchart of method 210 for filling the hollow space 40 with printable material 10 by the supply mechanism 2, in which case method 210 includes at least the following steps. - Step 310: Fill the print head 100 with material 10 through the opening 23 of the supply mechanism 2. - Step 320 involves generating an air impulse 26 to separate the material 10, particularly the granular clumps 10 from each other.

[0115] Step 310, which involves filling with granules 10, is performed manually or automatically, in which case the granules 10 slide into the lower region 24 of the supply mechanism 2 due to the influence of gravity.

[0116] Step 320, which generates the air impulse 26, is performed intermittently, and the granular clumps 10 are thrown up in the region of the air impulse 26 as follows: that is, as the granular clumps fall, an impulse acts on the granular clumps 10 below them, causing them to slide sequentially into the heated hollow space 40 of the print head 100.

[0117] Figure 9 is a flowchart of method 220 for closing the opening cross section 21 of the piston bush 4 with the piston 3, in which case method 220 includes the following steps. -Step 410 involves moving the piston 3 from the starting position 3a of the piston bottom 35 toward the nozzle 8 until it reaches the position 3b below the notch 44 of the piston bush 4, during which time, - Step 420, the granules 10 are sheared by sliding the piston bottom 35 next to the notch 44.

[0118] Figure 10 is a flowchart of method 230 for transitioning a material from a solid phase 10 to a liquid phase 12 via a plastic phase 11, in which case method 230 includes the following steps. - Step 510 involves heating materials 10, 11, and 12 by heating elements 61 and 63 of the nozzle head 6 across state zones A, B, C, D, and E of the print head 100, wherein state zones A, B, C, D, and E are at the temperature T of material 10. S The heating step 510 represents the aggregation state of the material which depends on the heating elements 61 and 63, thereby changing the aggregation state of the materials 10, 11, and 12 from the solid phase 10 through the plastic phase 11 to the liquid phase 12 across state zones A, B, C, D, and E. - Step 520 involves mixing materials 11 and 12 during step 240 of compression.

[0119] Figure 11 is a flowchart of method 240 for compressing materials 10, 11, and 12. The compression process 240 includes the following steps: - Step 610 involves pre-compressing materials 10, 11, and 12 by feeding piston 3. - Step 620 to close nozzle 8, - Step 630 compresses materials 10, 11, and 12 by feeding piston 3. - Step 640: Hold piston 3 in holding position 3d.

[0120] Step 610, which pre-compresses materials 10, 11, and 12, is carried out while controlling the pressure and / or force by the feed of piston 3, in which case pre-compression is performed up to position 3c, and position 3c is reached when the material-dependent gradient and / or gradient angle of the force curve and / or pressure curve is reached and / or exceeds thereafter.

[0121] Step 630, in which materials 10, 11, and 12 are compressed, is carried out while controlling the pressure by moving the piston 3 with the nozzle 8 closed, at which point the peak pressure p d Aim for the holding position 3d until the peak pressure p is reached, or the holding position is set to the peak pressure p d Defined by:

[0122] During the compression step 630, the nozzle 8 is closed and the piston needle 32 is submerged in the molten space 81 of the nozzle head 6, so that a portion of the liquid phase 12 is removed from the upper region of the molten space 81 and returned to the mixing zone C from the molten zone D through the opening 71 of the kidney-shaped member 7, so that the portion of the liquid phase 12 is mixed in the mixing zone C with the plastic phase 11 coming from the plasticization zone B.

[0123] The piston 3 is held in the holding position 3d, and in this case, during the holding process 640, the pressure p of the liquid phase 12 L and temperature TL The system measures the values ​​and checks the measured values ​​using the evaluation unit 114 to manage the functionality of the compression process 240.

[0124] During step 640, which holds the piston 3 in the holding position 3d, the nozzle 8 is closed and the piston needle 32 is submerged in the molten space 81 as follows: that is, a portion of the liquid phase 12 is removed from the upper region of the molten space 81 through the opening 71 of the kidney-shaped member 7 and returned from the molten zone D to the mixing zone C, thereby allowing the portion of the liquid phase 12 to mix with the plastic phase 11 coming from the plasticization zone B in the mixing zone C.

[0125] Figure 12 is a flowchart of method 250 for detecting the elastic constant of the liquid phase 12, in which case method 250 includes the following steps. - After the completion of the holding step 640, from the holding position 3d, the molten material pressure p L The target pressure p e Step 710 involves driving the vehicle back to the target position 3e, which is achieved when the pressure reaches that point, while maintaining pressure control. - Peak pressure p d and target pressure p e Step 720 detects the pressure difference between, - Step 730 detects the distance between the holding position 3d and the target position 3e. - Step 740: Calculate the elastic constant of the liquid phase 12.

[0126] Figure 13 is a flowchart of method 260 for preparing liquid phase 12 for printing, in which case method 260 includes the following steps. - Step 810 actively reduces the pressure of the liquid phase 12 by pulling back the piston 3 depending on the elastic constant. - Step 820: Open nozzle 8. [Explanation of Symbols]

[0127] 1. Printhead housing 2 Supply mechanism 3 pistons 3a Piston starting position 3b Lower position of the piston bushing notch, shear position 3c Piston position 3D piston holding position 3e Piston target position 4 Piston bushings 6 Nozzle heads 7 Kidney-shaped member 8 nozzles 10 Materials (granules, granule mass, solid phase) 11 Material (plastic phase) 12. Molten material (liquid phase) 21 Open cross-section of the piston bush 23 Opening of the supply mechanism 24 Lower region of the supply mechanism 26 Air Impulse 32 Piston Needle 35 Piston bottom 36 Temperature Sensor 82 Temperature Sensor 83 Pressure Sensor 40 Hollow space 44 Notches 50 Cooling device 61,63 heating element 71 Opening of kidney-shaped member 81 Molten Space 100 printheads 110 Actuator device 111 Distance Sensor 112 Pressure Sensor 113 Control and Adjustment Unit 114 evaluation units 200 Methods for providing printable molten material 210 Step of filling the hollow space 220 Step of closing the open cross section of the piston bush 230 Steps to transfer materials 240 Steps to compress the material 250 Steps to detect the elastic constant of the liquid phase 260 Steps to prepare the liquid phase for printing. 310 Step of filling the print head with material. 320 Steps to generate air impulses 410 Steps to advance the piston 420 Step of shearing the granules 510 Step of heating the ingredients 520 Step of mixing the materials 610 Step of pre-compressing the material 620 Step to close the nozzle 630 Step to compress the material 640 Step of holding the piston in the retaining position 710 Step to return the piston and start driving. 720 Step to detect the pressure difference between the peak pressure and the target pressure. 730 Step to detect the distance between the holding position and the target position. 740 Steps to calculate the elastic constant of the liquid phase 810 Depressurization step 820 Steps to open the nozzle A Low Temperature Zone B Plasticization Zone C Mixing zone D Melting Zone p L Pressure of the molten material (liquid phase) p d Peak pressure p e Target pressure T L liquid phase temperature

Claims

1. A method (200) for providing a printable molten material (12) to operate a print head (100) for a 3D printer, The above method (200) includes the following steps, namely - A step (210) of filling the hollow space (40) with printable material (10) using a supply mechanism (2), - Step (220) of closing the opening cross section (21) of the piston bush (4) by moving the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100), - A step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11), - A step (240) of compressing the materials (10, 11, 12), - A step (250) to detect the elastic constant of the liquid phase (12), - Step (260) of preparing the liquid phase (12) for printing, It includes, The filling step (210) of filling the hollow space (40) with printable material (10) using the supply mechanism (2) includes at least the following steps: - A step (310) of filling the print head (100) with the material (10) through the opening (23) of the supply mechanism (2), - A step (320) in which an air impulse (26) is generated to separate the material (10), which is a plurality of granular clumps (10), from each other, and the air impulse (26) acts on the granular clumps (10) in the lower region (24) of the supply mechanism (2), It includes, The filling step (310) of filling the granular mass (10) is performed manually or automatically, in which case the granular mass (10) is slid into the lower region (24) of the supply mechanism (2) by the influence of gravity. The method (200) is characterized by intermittently performing the step (320) of generating the air impulse (26), throwing the granular mass (10) up in the region of the air impulse (26) as follows, that is, applying an impulse to the granular mass (10) below it as it falls, and sequentially sliding it into the heated hollow space (40) of the print head (100).

2. The method according to claim 1 (200), characterized in that at least the closing step (220), the transfer step (230), the compression step (240), the elastic constant detection step (250), and the printing preparation step (260) are performed by the control of an actuator device (110) for controlling the piston (3) by a control / adjustment unit (113), and in this case, the results of an evaluation unit (114) based on measured values ​​of sensors (36, 82, 83, 111, 112) are transferred to the control / adjustment unit (113).

3. A method (200) for providing a printable molten material (12) to operate a print head (100) for a 3D printer, The above method (200) includes the following steps, namely - A step (210) of filling the hollow space (40) with printable material (10) using a supply mechanism (2), - Step (220) of closing the opening cross section (21) of the piston bush (4) by moving the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100), - A step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11), - A step (240) of compressing the materials (10, 11, 12), - A step (250) to detect the elastic constant of the liquid phase (12), - Step (260) of preparing the liquid phase (12) for printing, It includes, The step (220) of closing the opening cross-sectional portion (21) of the piston bush (4) with the piston (3) includes the following steps: - Step (410) of advancing the piston (3) from the starting position (3a) of the piston bottom (35) of the piston (3) towards the nozzle (8) until it reaches the position (3b) below the notch (44) of the piston bush (4), and in this case, - The step (420) of shearing the granules (10) by sliding the piston bottom (35) near the notch (44), A method (200) characterized by including the following.

4. Step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11) includes the following steps, namely - A step (510) of heating the material (10, 11, 12) by heating elements (61, 63) of the nozzle head (6) across the state zones (A, B, C, D, E) of the print head (100), wherein the aggregated state of the material (10) in the state zones (A, B, C, D, E) is the temperature (T) of the material (10). Ｓ The heating step (510) depends on the following, and changes the aggregated state of the materials (10, 11, 12) across the state zones (A, B, C, D, E) from a solid phase (10) through a plastic phase (11) to a liquid phase (12) by applying heating energy from the heating elements (61, 63), - During the compression step (240), the step (520) of mixing the materials (11, 12) is performed. The method according to claim 1 or 2 (200), characterized in that it includes the following:

5. The step (240) of compressing the aforementioned materials (10, 11, 12) includes the following steps, namely - A step (610) of pre-compressing the material (10, 11, 12) by advancing the piston (3), - The step (620) of closing the nozzle (8), - Step (630) of compressing the material (10, 11, 12) by advancing the piston (3), - The step (640) of holding the piston (3) in the holding position (3d), The method according to claim 1, 2, or 4 (200), comprising:

6. The method according to claim 5 (200), characterized in that the step (610) of pre-compressing the material (10, 11, 12) is carried out while controlling the pressure and / or force by the feed of the piston (3), and in this case, pre-compression is performed up to the position (3c) reached when the material-dependent gradient and / or gradient angle of the force curve and / or pressure curve is reached and / or exceeds therein.

7. The method according to claim 5 (200), characterized in that the step (630) of compressing the materials (10, 11, 12) is carried out while controlling the pressure by advancing the piston (3) with the nozzle (8) closed, and at that time aiming for the holding position (3d) until the peak pressure (pd) is reached.

8. A method (200) for providing a printable molten material (12) to operate a print head (100) for a 3D printer, The above method (200) includes the following steps, namely - A step (210) of filling the hollow space (40) with printable material (10) using a supply mechanism (2), - Step (220) of closing the opening cross section (21) of the piston bush (4) by moving the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100), - A step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11), - A step (240) of compressing the materials (10, 11, 12), - A step (250) to detect the elastic constant of the liquid phase (12), - Step (260) of preparing the liquid phase (12) for printing, It includes, The step (240) of compressing the aforementioned materials (10, 11, 12) includes the following steps, namely - A step (610) of pre-compressing the material (10, 11, 12) by advancing the piston (3), - The step (620) of closing the nozzle (8), - Step (630) of compressing the material (10, 11, 12) by advancing the piston (3), - The step (640) of holding the piston (3) in the holding position (3d), It includes, During the compression step (630), the nozzle (8) is closed and the piston needle (32) is submerged in the molten space (81) of the nozzle head (6) as follows: that is, a portion of the liquid phase (12) in the upper region of the molten space (81) is submerged in the molten space (81) of the nozzle head (6) so that it is removed by passing through the opening (71) of the intermediate member (7) and returning from the molten zone (D) to the mixing zone (C), thereby mixing the portion of the liquid phase (12) with the plastic phase (11) coming from the plasticization zone (B) in the mixing zone (C). (200)

9. The method according to claim 5 or 7 (200), characterized in that the piston (3) is held in the holding position (3d), the pressure (pL) and temperature (TL) of the liquid phase (12) are measured during the step (640) of holding the piston (3) in the holding position (3d), the measured values ​​are checked by an evaluation unit (114), and the function of the step (240) of compressing the material (10, 11, 12) is controlled.

10. A method (200) for providing a printable molten material (12) to operate a print head (100) for a 3D printer, The above method (200) includes the following steps, namely - A step (210) of filling the hollow space (40) with printable material (10) using a supply mechanism (2), - Step (220) of closing the opening cross section (21) of the piston bush (4) by moving the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100), - A step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11), - A step (240) of compressing the materials (10, 11, 12), - A step (250) to detect the elastic constant of the liquid phase (12), - Step (260) of preparing the liquid phase (12) for printing, It includes, The step (240) of compressing the aforementioned materials (10, 11, 12) includes the following steps, namely - A step (610) of pre-compressing the material (10, 11, 12) by advancing the piston (3), - The step (620) of closing the nozzle (8), - Step (630) of compressing the material (10, 11, 12) by advancing the piston (3), - The step (640) of holding the piston (3) in the holding position (3d), It includes, During the step (640) of holding the piston (3) in the holding position (3d), the nozzle (8) is closed and the piston needle (32) is submerged in the molten space (81) as follows: that is, a portion of the liquid phase (12) in the upper region of the molten space (81) is returned to the mixing zone (C) from the molten zone (D) through the opening (71) of the intermediate member (7) and removed, thereby mixing the portion of the liquid phase (12) with the plastic phase (11) coming from the plasticization zone (B) in the mixing zone (C). This is a method (200) characterized by this configuration.

11. A method (200) for providing a printable molten material (12) to operate a print head (100) for a 3D printer, The above method (200) includes the following steps, namely - A step (210) of filling the hollow space (40) with printable material (10) using a supply mechanism (2), - Step (220) of closing the opening cross section (21) of the piston bush (4) by moving the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100), - A step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11), - A step (240) of compressing the materials (10, 11, 12), - A step (250) to detect the elastic constant of the liquid phase (12), - Step (260) of preparing the liquid phase (12) for printing, It includes, The step (250) of detecting the elastic constant of the liquid phase (12) includes the following steps: - After the step (640) of holding the piston (3) in the holding position (3d) is completed, the molten material pressure (p Ｌ ) is the target pressure (p ｅ Step (710) involves moving the piston (3) back to the target position (3e) achieved when it reaches the target position (3e) while controlling the pressure, - Peak pressure (p ｄ ) and the target pressure (p ｅ The step (720) of detecting the pressure difference between ) and - Step (730) of detecting the distance between the holding position (3d) and the target position (3e), - A step (740) to calculate the elastic constant of the liquid phase (12), A method (200) characterized by including the following.

12. A method (200) for providing a printable molten material (12) to operate a print head (100) for a 3D printer, The above method (200) includes the following steps, namely - A step (210) of filling the hollow space (40) with printable material (10) using a supply mechanism (2), - Step (220) of closing the opening cross section (21) of the piston bush (4) by moving the piston (3) from the starting position (3a) toward the nozzle (8) of the print head (100), - A step (230) of transitioning the material from a solid phase (10) to a liquid phase (12) via a plastic phase (11), - A step (240) of compressing the materials (10, 11, 12), - A step (250) to detect the elastic constant of the liquid phase (12), - Step (260) of preparing the liquid phase (12) for printing, It includes, The step (260) of preparing the liquid phase (12) for printing includes the following steps: - A step (810) of reducing the pressure of the liquid phase (12) by pulling back the piston (3) depending on the elastic constant, - The step (820) of opening the nozzle (8), A method (200) characterized by including the following.

13. A print head (100) for a 3D printer to carry out the method (200) according to any one of claims 1 to 12, The 3D printer print head (100) includes an actuator device (110) for controlling the piston (3) located within the housing (1) of the print head (100), a supply mechanism (2) for the printable material (10), a flange (5) located in the housing (1) and the supply mechanism (2) and equipped with a cooling device (50), a nozzle head (6) equipped with heating elements (61, 63) for transferring the material (10) from a solid phase (10) through a plastic phase (11) to a liquid phase (12), and a nozzle (8) for discharging the liquid phase (12) of the material (10) from the nozzle head (6), The print head (100) is characterized in that the control and adjustment unit (113) is provided for controlling the actuator device (110) for moving the piston (3) in accordance with the operating strategy to be implemented for filling and printing, and for controlling the heating elements (61, 63).

14. The print head (100) according to claim 13, characterized in that the evaluation unit (114) is provided to evaluate the measured values ​​of the sensors (36, 82, 83, 111, 112) of the print head (100) and to transfer the results to the control and adjustment unit (113) for the control of the actuator device (110) and for the control of the heating elements (61, 63).

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