阅读说明：本技术 利用力反馈以打印非均匀丝的fdm打印机和方法 (FDM printer and method for printing non-uniform filaments using force feedback ) 是由 R·A·M·希克梅特 J·P·J·范奥斯 于 2018-05-18 设计创作，主要内容包括：本发明提供了一种用于3D打印3D物品(1)的方法,该方法包括：使用用于通过打印机喷嘴(502)排出3D可打印材料的力,将3D可打印材料(201)提供至打印机喷嘴(502),以及在打印阶段期间经由打印机喷嘴(502)使包括3D可打印材料(201)的丝(320)沉积,以提供包括3D打印的材料(202)的3D物品(1),其中该方法还包括：感测力相关参数,力相关参数用于控制3D可打印材料(201)的挤出速率。(The invention provides a method for 3D printing of a 3D article (1), the method comprising: providing 3D printable material (201) to a printer nozzle (502) using a force for discharging the 3D printable material through the printer nozzle (502), and depositing a filament (320) comprising the 3D printable material (201) via the printer nozzle (502) during a printing phase to provide a 3D item (1) comprising the 3D printed material (202), wherein the method further comprises: sensing a force-related parameter for controlling an extrusion rate of the 3D printable material (201).)

1. A method of 3D printing a 3D item (1) by fused deposition modeling using a fused deposition modeling 3D printer (500), the fused deposition modeling 3D printer (500) including a liquefier or heater (573), the liquefier or heater (573) configured to heat a 3D printable thermoplastic polymer material (201) upstream of a printer nozzle (502), the method comprising: providing the 3D printable thermoplastic polymer material (201) to the printer nozzle (502), the 3D printable thermoplastic polymer material (201) having a glass transition temperature (Tg) and/or a melting point (Tm), heating the 3D printable thermoplastic polymer material (201) to a temperature of at least the glass transition temperature (Tg) or at least the melting point (Tm) of the 3D printable thermoplastic polymer material (201) using the liquefier or the heater (573), discharging the 3D printable thermoplastic polymer material (201) through the printer nozzle (502) using a force, and depositing a filament (320) comprising 3D printable thermoplastic polymer material (201) via the printer nozzle (502) during a printing phase to provide the 3D item (1) comprising 3D printed thermoplastic polymer material (202), wherein the method further comprises: sensing a force-related parameter for controlling an extrusion rate of the 3D printable thermoplastic polymer material (201) from the printer nozzle (502) by a sensor (720), wherein the sensor (720) is arranged to sense the force-related parameter at a position upstream of the liquefier or the heater (573).

2. The method of claim 1, using the fused deposition modeling 3D printer, the fused deposition modeling 3D printer comprising a 3D printing phase unit (530), the 3D printing phase unit (530) comprising a printer head (501) and the printer nozzle (502), wherein the method comprises: providing 3D printable thermoplastic polymer material (201) to the liquefier or the heater (573) and then to the printer nozzle (502) by an applicator (1575) via a transport channel or conduit (710), wherein the sensor (720) is applied at least one of the following locations:

(i) at the position of the spreader (1575),

(ii) at the transport channel or conduit (710),

(iii) -a flexible coupling element arranged between the printer nozzle (502) and the printer head (501), wherein the printer nozzle (502) is movably associated with the printer head (501),

(iv) at the exterior of the 3D printing phase unit (530).

3. The method according to claim 1 or 2, wherein the method comprises: sensing the force-related parameter for controlling the extrusion rate of the wire (320), and wherein the method comprises: sensing the force-related parameter for keeping the extrusion rate of the filament (320) constant during at least part of the printing phase.

4. The method according to any one of the preceding claims, wherein the method comprises: providing the filament (320) to the printer nozzle (502) with an applicator (1575), the applicator (1575) configured to provide the filament (320) to the printer nozzle (502), wherein the applicator comprises a rotating element (1576) for transporting the filament (320), and wherein the method comprises: controlling a torque applied to a rotating element (1576) to control the extrusion rate of the 3D printable material (201).

5. The method according to any one of the preceding claims, wherein the method comprises: transporting the filament (320) through a transport channel (710), wherein the transport channel (710) comprises an upstream portion (711) and a downstream portion (712), the upstream portion (711) and the downstream portion (712) being interrelated via a pressure sensor (720), the pressure sensor (720) being configured to sense the force-related parameter, the force-related parameter being configured to control an extrusion rate of the 3D printable material (201).

6. The method of claim 5, wherein the downstream portion (712) comprises the printer nozzle (502).

7. The method according to any of the preceding claims, wherein the printer nozzle (502) comprises a printer nozzle wall (503), the 3D printable material (201) being guided along the printer nozzle wall (503), and wherein the printer nozzle wall (503) comprises a pressure sensor (720), the pressure sensor (720) being for sensing the force-related parameter, the force-related parameter being for controlling an extrusion rate of the 3D printable material (201).

8. The method according to any of the preceding claims 6 to 7, wherein the method further comprises: processing particulate 3D printable material (301) into the filament (320) for introduction into the printer head (501).

9. A fused deposition modeling 3D printer (500), the fused deposition modeling 3D printer (500) using the method of any of claims 1 to 8, wherein the fused deposition modeling 3D printer (500) comprises: (a) a printer head (501), the printer head (501) comprising a printer nozzle (502); and (b) a 3D printable material providing device (570), the 3D printable material providing device (570) being configured to provide 3D printable material (201) to the printer head (501), wherein the fused deposition modeling 3D printer (500) is configured to deposit a filament (320) comprising 3D printable material (201) via the printer nozzle (502) using a force for discharging the 3D printable material by the printer nozzle (502) during a printing phase, and wherein the fused deposition modeling 3D printer (500) further comprises: (c) a pressure sensor (720), the pressure sensor (720) configured for sensing a force-related parameter for controlling an extrusion rate of the 3D printable material (201) from the printer nozzle (502).

10. The fused deposition modeling 3D printer (500) of claim 9, further comprising an applicator (1575), the applicator (1575) configured to provide the filament (320) to the printer nozzle (502), wherein the applicator (1575) comprises a rotating element (1576) for transporting the filament (320), and wherein the method comprises: controlling torque on the rotating element (1576).

11. The fused deposition modeling 3D printer (500) of any of the preceding claims 9 to 10, further comprising a transport channel (710), wherein the fused deposition modeling 3D printer (500) is configured to transport the filament (320) through the transport channel (710), wherein the transport channel (710) comprises an upstream portion (711) and a downstream portion (712), the upstream portion (711) and the downstream portion (712) being interrelated via a pressure sensor (720), the pressure sensor (720) being configured to sense the force related parameter, the force related parameter being configured to control an extrusion rate of the 3D printable material (201).

12. The fused deposition modeling 3D printer (500) of claim 11, wherein the downstream portion (712) includes the printer nozzle (502).

13. The fused deposition modeling 3D printer (500) according to any of the preceding claims 9 to 12, wherein the printer nozzle (502) comprises a printer nozzle wall (503), the filament (320) being guided along the printer nozzle wall (503), and wherein the printer nozzle wall (503) comprises a pressure sensor (720), the pressure sensor (720) being for sensing the force related parameter, the force related parameter being for controlling the extrusion rate of the 3D printable material (201).

14. The fused deposition modeling 3D printer (500) of any of the previous claims 9 to 13, further comprising an extruder for transforming granular 3D printable material (301) into filaments (320) for introduction into the printer head (501).

15. The fused deposition modeling 3D printer (500) of any of the preceding claims 9 to 14, wherein the fused deposition modeling 3D printer (500) is configured to maintain the extrusion rate of the filament (320) constant during at least part of the printing phase by maintaining the force constant.

Technical Field

The present invention relates to a method of manufacturing a 3D (printed) article by fused deposition modeling. The invention also relates to a 3D (printed) article, such as obtainable with such a method. In addition, the invention relates to a 3D printer that can be used for such a method.

Background

Additive manufacturing (such as fused deposition modeling printing) is known in the art. For example, US2015266235 describes a system comprising: a first system configured and arranged to combine at least two different input materials; a controller coupled with the first system and configured to independently control a feed rate of each of the different input materials to the first system to generate a treated material having a composition that varies along its length; and a second system configured and arranged to add a synchronization feature to the processed material. The synchronization feature may be used by the material deposition system to synchronize changes in composition of the processed material during additive manufacturing of the article using the processed material. The controller may be configured to create data that may be used by the material deposition system to synchronize the processed material with the position of the article during additive manufacturing. Further, the second system may include a material forming system, and the synchronization feature may include a shape added to the processed material. Further, it is also described that the deposition rate (volume of material deposited within each linear distance moved by the material deposition apparatus) varies along the filament length as it is created in order to achieve different filament thicknesses needed to match layers of different thicknesses while keeping the width constant. Alternatively, the width of the filament may be varied in order to achieve the desired layer thickness, keeping the material deposition rate constant. In some cases, the width and material deposition rate can vary along the length of the filament.

Disclosure of Invention

Digital manufacturing will gradually change the nature of global manufacturing over the next 10 to 20 years. One aspect of digital manufacturing is 3D printing. Currently, many different technologies have been developed to produce various 3D printed articles using various materials (such as ceramics, metals, and polymers). 3D printing can also be used to produce molds, which can then be used to replicate the article.

To make the mold, it has been proposed to use polymer injection techniques. This technique utilises layer-by-layer deposition of a photo-polymerisable material which is cured after each deposition to form a solid structure. While this technique produces smooth flat surfaces, photocurable materials are not very stable and they also have relatively low thermal conductivity that is useful for injection molding applications.

The most widely used additive manufacturing technique is a process known as Fused Deposition Modeling (FDM). Fused Deposition Modeling (FDM) is an additive manufacturing technique that is commonly used for modeling, prototyping, and production applications. FDM works by following the "additive" principle by laying materials in layers; the plastic wire or wire is unwound from the coil and material is supplied to produce the part. It may be the case that (for example for thermoplastics) the filaments are melted and extruded before being laid. FDM is a rapid prototyping technique. Other terms for FDM are "fused filament fabrication" (FFF) or "filament 3D printing" (FDP), which are considered equivalent to FDM. Typically, FDM printers use thermoplastic filaments that are heated to their melting point and then extruded layer by layer (or indeed filament by filament) to create a three-dimensional article. FDM printers are relatively fast and can be used to print complex items. Such printers are used to print various shapes using various polymers. Techniques to produce LED light fixtures and lighting solutions have also been further developed.

In these FDM printers, the filament is fed to the nozzle at a constant speed. Therefore, in order to obtain a constant rate of material flow from the nozzle, a wire having a constant diameter must be used. Producing a filament with a substantially constant diameter is relatively complex and results in a high value of the filament. Furthermore, even if its performance is optimized, currently available wire diameters appear to have a tolerance of about 1.3%. This also often leads to undesirable visual defects in the printed article. Thus, the ribbed structure is provided with ribs that are not uniform in height or width, which may be undesirable for a variety of reasons.

Accordingly, an aspect of the present invention provides an alternative 3D printing method and/or 3D (printed) article, which preferably further at least partly obviates one or more of the above-mentioned drawbacks. An aspect of the present invention further provides an alternative 3D printer, which preferably further at least partly obviates one or more of the above-mentioned drawbacks. It may be an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art and/or to provide a useful alternative.

In this context, in order to be able to use a wire without a constant cross-sectional area, in other solutions we propose to use a feeder system with a capillary and a force measuring unit, wherein, in an embodiment, the force for feeding the wire is kept constant while the wire is fed into the nozzle. In this way, the flow into the nozzle of the FDM printer can be kept constant when using filaments with non-uniform cross-sections. Hence, in addition to this, in this context we also suggest a method wherein we measure the force applied to the wire and keep it constant during the printing process, rather than during feeding the wire at a constant speed.

The volumetric flow Q of a polymer having a viscosity of η is derived from the following equation that a capillary tube having a radius r and a length L is related to the pressure drop, which in turn is related to the force F:

to this end, in an embodiment, the wire may be fed through a capillary. For example, 110cm³/h(3.05 10^-8m³/s), using a capillary with a diameter of 3.85mm and a length of 5mm and a polymer with a viscosity of 5K Pa · s, a force of 3 newtons needs to be used. If the diameter tolerance is 0.05mm, this means at a constant feeder speedThe flow rate is 3.15-10^-8m³And 2,94, 10^-8m³Because the fluctuations in filament diameter can lead to non-uniform printing. Without force feedback to keep the force constant, the force varied between 2.895Nt (when the diameter was 3.9mm thick) and 3.1 newtons (when the diameter was 3.8 mm).

Accordingly, in a first aspect, the present invention provides a method of 3D printing a 3D article (also indicated herein as "article" or "3D printed article") by fused deposition modeling using a fused deposition modeling 3D printer, the fused deposition modeling 3D printer comprising a liquefier or heater configured to heat a 3D printable thermoplastic polymer material upstream of a printer nozzle, the method comprising: providing a 3D printable thermoplastic polymer material to a printer nozzle ("nozzle"), the 3D printable thermoplastic polymer material having a glass transition temperature (Tg) and/or a melting point (Tm), heating the 3D printable thermoplastic polymer material to a temperature of at least the glass transition temperature (Tg) or at least the melting point (Tm) of the 3D printable thermoplastic polymer material using a liquefier or heater, using a force for expelling the 3D printable thermoplastic polymer material through the printer nozzle, and depositing a filament comprising the 3D printable thermoplastic polymer material via the printer nozzle during a printing phase to provide a 3D item comprising the 3D printed thermoplastic polymer material, wherein the method further comprises: sensing a force-related parameter by a sensor for controlling the extrusion rate of the 3D printable thermoplastic polymer material (from the printer nozzle), wherein the sensor is arranged to sense the force-related parameter at a position upstream of the liquefier or heater.

In addition to the term "extrusion rate", the term "flow rate" may also be used. It particularly refers to the rate at which the filament escapes from the printer nozzle. The term "extrusion rate" especially refers to the mass per unit time, especially herein the rate of the 3D printable material at which the 3D printable material is discharged from the printer nozzle. Such a method and such a 3D printer (see also further below) may be such that filaments from polymer manufacturers can be used without micronization. It also enables the FDM printer to produce articles with a reduced number of defects. Further, this approach (and 3D printers) can allow highly controlled thickness or diameter filaments to escape the printer nozzle. This can be used to generate layers with relatively the same dimensions, but it can also be used to control the dimensions with higher accuracy. Sensing may be accomplished with a sensor. The sensor may be functionally coupled to the control system. The control system may control a force for discharging the 3D printable material through the printer nozzle. In this way, a feedback loop may be provided that may be used to control the filament diameter of the filaments discharged from the nozzle, such as to keep the extrusion rate constant. Accordingly, the present invention provides an FDM printer and method for controlled printing based on non-uniform filaments as input material using force feedback. In particular, the method is a single wire method, i.e. a single wire is guided to the printer head, rather than two or more wires.

As indicated above, the present invention provides a method of 3D printing a 3D article by fused deposition modeling using a fused deposition modeling 3D printer, the fused deposition modeling 3D printer comprising a liquefier or heater configured to heat a 3D printable thermoplastic polymer material upstream of a printer nozzle, the method comprising: the 3D printable thermoplastic polymer material is provided to a printer nozzle. The 3D printing stage unit comprises a printer head and a printer nozzle. The 3D printable thermoplastic polymer material has a glass transition temperature (Tg) and/or a melting point (Tm). The 3D printable thermoplastic polymer material is heated to a temperature of at least a glass transition temperature (Tg) or at least a melting point (Tm) of the 3D printable thermoplastic polymer material by using a liquefier or heater. The 3D printable material exits the nozzle as a filament and is deposited on the stent (or on a previous 3D printed material on the stent). Thus, when the 3D printable material has been deposited on the 3D printed material on the support, the 3D printable material may be deposited directly on the support, or may be deposited indirectly on the support. The 3D printable material deposited on the support is indicated as 3D printed material, or as an item (including 3D printed material); see also below. During the printing phase of the method, a filament comprising 3D printable material is deposited via a printer nozzle. In this way, a 3D article comprising 3D printed material is provided.

The 3D printable material may be provided to the printer head as a filament or may be provided as a granular material. In the latter embodiment, an additional extruder may convert the particulate material into filaments. Thus, the 3D printable material may be provided as a filament or as a granular material, but in both embodiments is printed ("extruded") as a filament.

Further, optionally, the 3D printable material is provided as a filament, but processed into a granular material, which processed material is again transformed by the additional extruder into a filament for the printer head. This may be particularly useful when very irregular diameter wires are used. The filaments thus obtained may have a better controlled diameter, even in these cases the diameter may vary beyond expectations.

Thus, the 3D printable material is provided to the printer head as a filament. With the present invention, the filament thickness or diameter can be better controlled in all of the options described above. This may allow the use of filaments, even with sub-optimal constant thickness as with 3D printers, the difference in diameter can be handled as defined herein. With the present invention, the extrusion rate or printing of the 3D printable material may be kept substantially constant, or better controlled, if desired. Accordingly, the present invention provides for controlling the extrusion rate of 3D printable material. In other words, the rate at which the filaments exit the printer nozzle is controlled by controlling the force used to eject the 3D printable thermoplastic polymer material from the nozzle.

In all of the above options, the force is used to expel the 3D printable thermoplastic polymer material through the printer nozzle. When using directly printed wire, the force is then used to transport the wire through the printer head, for example, with a motor. In other embodiments, a force may be used to press the granular 3D printable material through the printer nozzle to provide the filament. Pressure may be used to extrude the 3D printable material to provide the filament.

During feeding of the filament at a constant speed, the recorded force will show up as a thickness dependent on the input diameter of the filament as the filament melts and is extruded through the printer head. Further, the rate at which the polymer is extruded through the nozzle is also dependent on the force. Thus, the force applied may be a better parameter than, for example, the rate at which the polymer filaments are fed into the extruder to achieve a constant extrusion rate. Thus, the method further comprises: sensing, by a sensor, a force-related parameter for controlling extrusion of the 3D printable thermoplastic polymer material from the printer nozzle. The sensor is arranged to sense a force related parameter at a location upstream of the liquefier or heater.

Thus, in a particular embodiment, the method comprises: a force-related parameter for controlling the rate of extrusion of the filament is sensed. Here, the term "control" may particularly denote keeping the flow at a desired predetermined value (see also further below). The diameter may vary over time, associated with the design of the 3D article, for specific purposes. In particular embodiments, it may be desirable to have a 3D printed filament of constant thickness, for example, when printing a wall or the like. Thus, in a particular embodiment, the method may comprise: sensing a force-related parameter for keeping the flow of the filament constant during at least part of the printing phase. The force may be sensed in several ways and/or at several locations (stages) within the 3D printer (printing process), and one or more may be selected from several ways and/or at several locations (stages) within the 3D printer (printing process).

In an embodiment, a fused deposition modeling 3D printer may include a 3D printing phase unit including a printer head and a printer nozzle. The 3D printable thermoplastic polymer material is provided by the spreader to the liquefier or heater and then to the printer nozzle via a transport channel or conduit. The sensor may be applied at least one of the following locations: (i) at the applicator, (ii) at the transport channel or conduit, (iii) at a flexible coupling element arranged between the printer nozzle and the printer head, wherein the printer nozzle is movably associated with the printer head, (iv) at an exterior of the 3D printing stage unit. Outside the 3D printing phase unit means that the sensor takes measurements at the 3D printing phase unit, not in the molten state of the 3D printable thermoplastic polymer material. For example, the sensor may measure a force-related parameter on the exterior of the printer head. For example, the sensor may measure a force-related parameter on the exterior of the holding device that mechanically holds the printer head.

In embodiments, an applicator (such as a motor) may be applied to force the filaments through the 3D printer, such as through a capillary tube (see also below) or through a printer nozzle. The torque required to rotate the rotating element for transporting the wire can be sensed and controlled. In this way, the flow rate can be kept constant.

The term "control" and similar terms refer at least in particular to the determination of an action or the operation of a supervising element. Thus, "controlling" and similar terms herein may refer, for example, to performing an action on an element (either determining an action or supervising the operation of an element), or the like, such as, for example, measuring, displaying, activating, turning on, shifting, changing a temperature, or the like. In addition, the term "control" and similar terms may additionally include monitoring. Thus, the term "control" and similar terms may include performing an action on an element and also performing an action on an element and monitoring the element. Thus, in an embodiment, the method comprises: providing the filament to a printer nozzle with an applicator (configured to provide the filament to the printer nozzle), wherein the applicator comprises a rotating element for transporting the filament, and wherein the method comprises: controlling the torque on the rotating element. Thus, the method may comprise: controlling a torque applied to the rotating element to control an extrusion rate of the 3D printable material. By applying a torque, not only the flow can be controlled, but also a force related parameter can be (implicitly) sensed.

Alternatively or additionally, the method may comprise: transporting the filament through a transport channel, wherein the transport channel comprises an upstream portion and a downstream portion, the upstream portion and the downstream portion being interrelated via a pressure sensor for sensing a force-related parameter for controlling the extrusion of the 3D printable material. The greater the force, the greater the distance between the two parts may be. Thus, the distance between the two parts can be used as a force measurement. The distance between the two parts may be small and the difference in distance may also be small; for example, the default distance may be in the range of 0 μm to 2000 μm, the distance difference due to the difference in force may be, for example, (also) in the range of 0 μm to 2000 μm, where 0 μm indicates no force at all, and 2000 μm may be the maximum actual force. Thus, in these embodiments, the distance may be a force-related parameter.

Further, the two parts may be coupled to each other via flexible coupling elements, allowing some translation along the transport axis of one part relative to the other part. In a particular embodiment, the downstream portion includes a printer nozzle. Thus, the printer nozzle may be configured to be substantially independent of the printer head and movably associated with the printer head. The sensor may comprise a flexible coupling element.

In further specific embodiments, a transport channel may be employed, wherein portions of the channel comprise relatively flexible portions. During operation, the transport channel maintains its diameter at the process pressure parameter. However, depending on the pressure, the flexible portion may bulge more or less. This can be measured with a pressure sensor, by means of which the force can be measured. Also in this way, a force related parameter can be sensed.

Alternatively or additionally, the printer nozzle comprises a printer nozzle wall along which the 3D printable material is guided, and wherein the printer nozzle wall may comprise a pressure sensor for sensing a force related parameter for controlling the extrusion of the 3D printable material. When the 3D printable material is pressed through the nozzle, the pressure sensor will feel a force. Also in this way, a force related parameter can be sensed.

In further embodiments, sensors configured to measure strain in the transport channel may be used. When the transport channel is made of an elastic material, a force will be exerted on the transport channel during transport of the wire. The force will result in a small deformation (strain) that can be measured. When the strain is sensed and held constant, the force will also be held constant.

Thus, as indicated above, the method may comprise: providing the granulated 3D printable material and processing the granulated 3D printable material into a filament for further processing in the printer head.

In any case, the filament may be formed to its final thickness or diameter, ejected from the nozzle and deposited by pressing the 3D printable material through the nozzle and heating the 3D printable material in the nozzle. The temperature in the nozzle may be higher than the glass transition temperature and/or the melting temperature (see also below).

Any sensed force or other parameter related thereto, such as torque or energy consumption of the spreader, may reflect the force with which the 3D printable material is ejected from the nozzle. Therefore, the term "force-related parameter" is applied herein. A pressure sensor may be used to measure the force-related parameter. Thus, the term "force sensor" or "pressure sensor" is used herein. Thus, the sensor for sensing the force related parameter may be a force sensor or a pressure sensor. Alternatively or additionally, a sensor selected from the group consisting of: calibrated force sensors, torque sensors, piezoelectric sensors, capacitive sensors, resistive sensors, and the like.

As indicated above, the method comprises: depositing the 3D printable material during the printing phase. Herein, the term "3D printable material" refers to a material to be deposited or printed, and the term "3D printed material" refers to a material obtained after deposition. These materials may all be substantially identical, as the 3D printable material may particularly refer to the material in the printer head or extruder at high temperature while the 3D printed material refers to the same material, but at a later stage of being deposited. The 3D printable material is printed as a filament and also deposited. The 3D printable material may be provided as a filament or may be formed as a filament. Thus, whatever starting material is applied, the filament comprising the 3D printable material is provided by the printer head and is 3D printed.

Herein, the term "3D printable material" may also be indicated as "printable material". The term "polymeric material" may in embodiments refer to a mixture of different polymers, but may in embodiments also essentially refer to a single polymer type having different polymer chain lengths. Thus, the term "polymeric material" or "polymer" may refer to a single type of polymer, but may also refer to a plurality of different polymers. The term "printable material" may refer to a single type of printable material, but may also refer to a plurality of different printable materials. The term "printed material" may refer to a single type of printed material, but may also refer to a plurality of different printed materials.

Thus, the term "3D printable material" may also refer to a combination of two or more materials. Typically, these (polymeric) materials have a glass transition temperature T_gAnd/or melting temperature T_m. The 3D printable material will be heated by the 3D printer to a temperature of at least the glass transition temperature (typically at least the melting temperature) before exiting the nozzle. Thus, in a specific embodiment, the 3D printable material comprises a thermoplastic polymer having a glass transition temperature (T |)_g) And/or melting point (T)_m) And the printer head actions include: the 3D printable material is heated above the glass transition and, if it is a semi-crystalline polymer, above the melting temperature. In yet another embodiment, the 3D printable material includes a material having a melting point (T)_m) (thermoplastic) polymer, and the printer head action comprises: heating the 3D printable material to be deposited on the receiver item to a temperature of at least the melting point. The glass transition temperature is generally different from the melting temperature. Melting is a transition that occurs in crystalline polymers. Melting occurs when the polymer chains fall out of their crystalline structure and become a disordered liquid. A glass transition is a transition that occurs on an amorphous polymer (i.e., the chains of the polymer are not arranged in ordered crystals, but are merely interspersed in any way, even if they are solid). The polymer may be amorphousEssentially having a glass transition temperature without a melting temperature, or may be (semi-) crystalline, typically having both a glass transition temperature and a melting temperature, wherein the latter is typically larger than the former.

As indicated above, the present invention therefore provides a method comprising: providing a filament of 3D printable material and printing said 3D printable material on a substrate during a printing phase to provide said 3D item. Materials that may be particularly suitable as 3D printable material may be selected from the group consisting of: metals, glass, thermoplastic polymers, silicon, and the like. In particular, the 3D printable material comprises a (thermoplastic) polymer selected from the group consisting of: ABS (acrylonitrile butadiene styrene), nylon (or polyamide), acetate (or cellulose), PLA (polylactic acid), terephthalate (such as PET polyethylene terephthalate), acrylic (polymethyl acrylate, plexiglass, polymethylmethacrylate PMMA), polypropylene (or polypropylene), Polystyrene (PS), PE (such as expanded-high impact-polyethylene (or polyethylene)), Low Density (LDPE) High Density (HDPE)), PVC (polyvinyl chloride)) polyvinyl chloride (polychlorethane), and the like. Optionally, the 3D printable material comprises 3D printable material selected from the group consisting of: urea formaldehyde, polyester resins, epoxy resins, melamine formaldehyde, Polycarbonate (PC), thermoplastic elastomers, and the like. Optionally, the 3D printable material comprises a 3D printable material selected from the group consisting of polysulfone.

The printable material is printed on the receiver item. In particular, the receiver article may be or may consist of a build platform. The receiver article may also be heated during 3D printing. However, the receiver article may also be cooled during 3D printing.

In addition, the phrase "printed on a receiver article" and similar phrases include printing directly on a receiver article, or printing on a coating on a receiver article, or printing on 3D printed material previously printed on a receiver article. The term "receiver article" may refer to a printing platform, printing bed, base plate, support, build plate, or build platform, etc. In addition to the term "receiver article", the term "substrate" may also be used. In addition, the phrase "printed on the receiver article" and similar phrases include also printed on a separate substrate on or consisting of a printing platform, printing bed, support, build plate or build platform, etc. Thus, in addition to this, the phrase "printed on a substrate" and similar phrases include printing directly on a substrate, or on a coating printed on a substrate, or on a 3D printed material printed on a previous substrate. In the following, the term "substrate" is further used, which may refer to a printing platform, a printing bed, a substrate, a support, a build plate or a build platform, etc., or a separate substrate thereon or consisting of them.

Further, the invention relates to a software product that can be used to perform the method described herein.

The methods described herein provide 3D printed articles. Thus, the invention also provides in a further aspect a 3D printed article obtainable with the method described herein. In particular, the invention provides a 3D printed article comprising a 3D printed material, the 3D printed article comprising a ribbed structure comprising ridges and valleys defining height differences (Δ h) between adjacent ridges and valleys, wherein the height differences Δ h from the average are derived from the average height differences Δ h_avgIs equal to or less than 2%, such as equal to or less than 1%. The ribbed structure is inherent to FDM printing in nature. However, due to irregularities in the filaments, direct use of the filaments may result in additional features, such as height differences between ribs. With the present invention, this difference may be minimized.

The 3D printed article obtained (using the methods described herein) may itself be functional. For example, the 3D printed article may be a lens, a collimator, a reflector, or the like. Thereby, the obtained 3D object may (alternatively) be used for decorative or artistic purposes. The 3D printed article may comprise or be provided with functional components. The functional component may in particular be selected from the group consisting of: optical components, electrical components, and magnetic components. The term "optical component" especially refers to components having an optical function, such as lenses, mirrors, light sources (e.g. LEDs), etc. The term "electrical component" may for example refer to an integrated circuit, a PCB, a battery, a driver, but also to a light source (as a light source may be considered as an optical component and an electrical component), etc. The term "magnetic component" may for example refer to a magnetic connector, a coil, etc. Alternatively or additionally, the functional components may include thermal components (e.g., configured to cool or heat electrical components). Thus, the functional component may be configured to generate heat or remove heat, or the like.

Returning to the 3D printing process, a particular 3D printer may be used to provide the 3D printed article described herein. Accordingly, in yet another aspect, the present invention also provides a fused deposition modeling 3D printer ("printer" or "3D printer") comprising: (a) a printer head including a printer nozzle; and (b) a 3D printable material providing device configured to provide the 3D printable material to the printer head, wherein the fused deposition modeling 3D printer is configured to deposit a filament comprising the 3D printable material via the printer nozzle during the printing phase using a force for ejecting the 3D printable material (to the substrate) by the printer nozzle, and wherein the fused deposition modeling 3D printer further comprises (c) a pressure sensor configured for sensing a force related parameter for controlling the extrusion (in particular the extrusion rate) of the 3D printable material. The 3D printable material providing device may provide the filament including the 3D printable material to a printer head or may likewise provide the 3D printable material, wherein the printer head generates the filament including the 3D printable material. Accordingly, in an embodiment, the present invention provides a fused deposition modeling 3D printer, the fused deposition modeling 3D printer comprising: (a) a printer head including a printer nozzle; and (b) a filament providing device configured to provide a filament comprising 3D printable material to a printer head, wherein the fused deposition modeling 3D printer is configured to deposit the filament comprising 3D printable material via a printer nozzle during a printing phase using a force for ejecting the 3D printable material (to a substrate) through the printer nozzle, and in particular, the fused deposition modeling 3D printer further comprises: (c) a pressure sensor configured for sensing a force-related parameter for controlling the extrusion of the 3D printable material.

The pressure or force sensor may be any sensor for measuring the pressure in the channel, the pressure between two channel parts, the pressure on the flexible part, etc. In particular, the sensor is configured to sense a force in a range of 0.1N to 20N (such as 0.1 newton to 10 newtons).

In fact, some embodiments of the printer have been described above with respect to this method. For completeness, some of the embodiments described above are also reiterated below.

In a specific embodiment, the fused deposition modeling 3D printer further comprises an applicator, in particular configured to provide the filament to a printer nozzle, wherein the applicator may in particular comprise a rotating element for transporting the filament, and wherein the method comprises: controlling the torque on the rotating element.

As indicated above, in a further embodiment, the fused deposition modeling 3D printer may further comprise a transport channel, wherein the fused deposition modeling 3D printer is configured to transport the filament through the transport channel, wherein the transport channel comprises an upstream portion and a downstream portion, the upstream portion and the downstream portion being interrelated to each other via a pressure sensor for sensing a force related parameter for controlling the extrusion of the 3D printable material. For example, in an embodiment, the downstream portion includes a printer nozzle.

As indicated above, in a specific embodiment of the fused deposition modeling 3D printer, the printer nozzle may comprise a printer nozzle wall along which the filament is guided, and wherein the printer nozzle wall comprises a pressure sensor for sensing a force-related parameter for controlling the extrusion of the 3D printable material.

As indicated above, the 3D printable material providing device may provide the filament to the printer head either based on granular material processed into the filament or also based on the filament. Hence, in an embodiment of the fused deposition modeling 3D printer, the 3D printable material providing device is configured to provide the granular 3D printable material to the 3D printer, wherein the 3D printer further comprises an (additional) extruder for processing the 3D printable material into a filament (to be introduced into the printer head).

In particular embodiments, the fused deposition modeling 3D printer may be configured to maintain a constant rate of material extrusion (material weight/time) through the nozzle by maintaining the force constant during at least part of the printing phase.

Thus, in an embodiment, a fused deposition modeling 3D printer may include a control system functionally coupled to one or more force-related parameter sensors.

In addition to the term Fused Deposition Modeling (FDM)3D printer, the terms 3D printer, FDM printer, or printer may also be used briefly. The printer nozzle may also be indicated as a "nozzle" or sometimes as an "extruder nozzle".

Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

1 a-1 b schematically depict some common aspects of a 3D printer; and

fig. 2 a-2 e schematically depict some aspects of the methods and/or apparatus defined herein.

The schematic drawings are not necessarily drawn to scale.

Detailed Description

Fig. 1a schematically depicts some aspects of a 3D printer. Reference numeral 500 denotes a 3D printer. Reference numeral 530 denotes a functional unit configured to perform 3D printing (in particular, FDM 3D printing); the reference numeral may also indicate a 3D printing stage unit. The 3D printing stage unit (530) includes a printer head (501) and a printer nozzle (502). Here, a printer head (such as an FDM 3D printer head) for providing 3D printed material is depicted only schematically. Reference numeral 501 denotes a printer head. The 3D printer of the present invention may specifically comprise a plurality of printer heads, although other embodiments are also possible. Reference numeral 502 denotes a printer nozzle. The 3D printer of the present invention may specifically comprise a plurality of printer nozzles, although other embodiments are also possible. Reference numeral 320 indicates a filament of printable 3D printable material (as indicated above). For clarity, not all features of the 3D printer have been depicted, only those features that are particularly relevant to the present invention are depicted (see also further below).

The 3D printer 500 is configured to generate the 3D item 10 by depositing a plurality of filaments 320 on a receiver item 550, which receiver item 550 may be at least temporarily cooled in embodiments, wherein each filament 20 comprises a 3D printable material, such as having a melting point T_m. The 3D printer 500 is configured to heat the filament material upstream of the printer nozzle 502. This may be done, for example, using equipment that includes one or more extrusion and/or heating functions. Such equipment is indicated by reference numeral 573 and is disposed upstream of the printer nozzle 502 (i.e., at a time before the filament material exits the printer nozzle 502). The printer head 501 (thus) includes a liquefier or heater. Reference numeral 201 denotes a printable material. When deposited, the material is indicated as a (3D) printed material, which is indicated with reference numeral 202.

Reference numeral 572 designates a spool or drum of material, in particular in the form of a wire. The 3D printer 500 converts it into a filament or fiber 320 on a receiver article or already on the deposited printed material. Typically, the diameter of the filament downstream of the nozzle is reduced relative to the diameter of the filament upstream of the printer head. Thus, printer nozzles are sometimes (also) referred to as extruder nozzles. The 3D article 10 may be formed by arranging the filaments on each other and on each other. Reference numeral 575 denotes a wire supplying apparatus which, in addition to that, includes a reel or drum and a drive wheel, which are designated by reference numeral 576.

Reference character a indicates a longitudinal or silk axis.

Reference numeral C schematically depicts a control system, such as, in particular, a temperature control system, configured to control the temperature of receiver article 550. Control system C may include a heater capable of heating receiver article 550 to a temperature of at least 50℃, but particularly up to a range of about 350℃, such as at least 200℃.

Fig. 1a schematically depicts an applicator 1575 configured to provide the filament 320 to the printer nozzle 502, wherein the applicator includes a rotating element 1576 for transporting the filament 320. Here, a rotating wheel may be used to transport the wire 320.

Fig. 1b schematically depicts in more detail in 3D the printing of the 3D article 10 under construction. Here, in this schematic view, the ends of the wire 320 in a single plane are not interconnected, although in fact this may be the case in embodiments.

Fig. 1b also schematically depicts the diameter (indicated with reference D) of the filament 320 that is extruded only from the printer nozzle 502.

Accordingly, fig. 1 a-1 b schematically depict some aspects of a fused deposition modeling 3D printer 500, the fused deposition modeling 3D printer 500 including: (a) a first printer head 501, the first printer head 501 including printer nozzles 502; (b) a filament providing device 575 configured to provide a filament 320 comprising a 3D printable material 201 to a first printer head 501; and optionally (c) a receiver item 550. In fig. 1a to 1b, the first or second printable material or the first or second printed material is indicated with a generally indicating printable material 201 and a printed material 202.

A force feedback mechanism may be used to keep the material flow (weight material per unit time) constant by measuring the force applied by the feeder motor, e.g. by measuring the current (as an example of a force related parameter that can be sensed). It is also possible to cut the catheter and place a stress/strain gauge between the two parts to measure the force applied during extrusion as shown in fig. 2a, and an embodiment is shown in more detail in fig. 2 b. Thus, these figures further schematically illustrate the transport channel 710. A fused deposition modeling 3D printer (not shown in further detail, but see, e.g., fig. 1a) is configured to transport the filament 320 through a transport channel 710. The transport channel 710 comprises an upstream part 711 and a downstream part 712, the upstream part 711 and the downstream part 712 being interrelated via a pressure sensor 720, the pressure sensor 720 for sensing a force-related parameter for controlling the deposition of the 3D printable material 201. Based on the sensor signal, the control system C may control the force, for example, to keep the diameter of the filament 320 escaping from the printer nozzle 502 constant. For example, the distance between the upstream portion 711 and the downstream portion 712, indicated with reference d, may be used as the force-related parameter. Fig. 2a also schematically shows an applicator 1575, the applicator 1575 being configured to provide the filament 320 to the printer nozzle 502. When the force provided by the applicator is constant, the distance d will also be constant.

Fig. 2c schematically depicts several locations in the optional transport channel or conduit 710 where the pressure of the force sensor 720 may be applied, such as at the spreader 1575, but may also be at the nozzle 502. It should be noted that the configuration at the nozzle 502 is essentially different from the sensor 720 at the top of the figure. Thus, in an embodiment, the downstream portion 712 includes the printer nozzle 502. It should be noted that for purposes of illustrating the present invention, FIG. 2c depicts a number of possible locations for sensor 720. Further, fig. 2c also schematically depicts an (additional) extruder, indicated with reference numeral 600, for example. The granular 3D printable material 201 is fed into an extruder 600 and extruded into a filament 320 of 3D printable material 201. The wire may be fed to an applicator 1575 (not shown in full detail). Other locations where the force can be measured are within the nozzle as further illustrated in fig. 2 d. The volume in which the 3D printable thermoplastic polymer material is in the molten state (above Tg and Tm) is a very small volume, e.g. typically below 100mm³. Measuring pressure in such small volumes is rather difficult and/or inaccurate. Measuring the solid state (i.e. not)Molten state) of 3D printable thermoplastic polymer material (input filaments in the form of cables) is more straightforward and/or accurate. Fig. 2c schematically depicts an embodiment of an applicator 1575 configured to provide the filament 320 to the printer nozzle 502, wherein the applicator 1575 comprises a rotating element 1576 for transporting the filament 320. In such an embodiment, the method may include: controlling the torque on the rotary element 1576 (to control flow).

The sensor 720 may sense a force-related parameter at any location before the filament is heated to its glass transition temperature (Tg) and/or melting temperature (Tm) in the 3D printer 500.

The sensor 720 may sense a force-related parameter at a location outside of the 3D printing stage unit 530. The 3D printing stage unit 530 may be flexibly arranged as part of the 3D printer 500, such as, for example, a 3D printer chassis or housing.

Fig. 2D schematically depicts an embodiment, wherein the printer nozzle 502 comprises a printer nozzle wall 503, along which printer nozzle wall 503 the 3D printable material 201 is guided. The printer nozzle wall 503 comprises a pressure sensor 720, the pressure sensor 720 for sensing a force-related parameter, the force-related parameter for controlling the extrusion of the 3D printable material 201.

Fig. 2e schematically depicts an embodiment of a 3D printed article 1 comprising a 3D printed material 202. The 3D printed article 1 comprises a ribbed structure 2, the ribbed structure 2 comprising ridges 3 and valleys 4, the ridges 3 and the valleys 4 defining a height difference Δ h between adjacent ridges and valleys. Is indicated herein as Δ h₁、Δh₂、Δh₃、Δh₄The average of the different Δ h of the etc. may be Δ h_avg. From the mean height difference Δ h_avgIs equal to or less than 1%.

The term "plurality" means two or more.

The term "substantially" (such as "consisting essentially of … …") herein should be understood by those skilled in the art. The term "substantially" may also include embodiments having "completely," "entirely," and the like. Therefore, adjectives may also be substantially removed in embodiments. Where applicable, the term "substantially" may also relate to 90% or more (such as 95% or more), particularly 99% or more, even more particularly 99.5% or more, including 100%. The term "comprising" also includes embodiments in which the term "including" means "consisting of … …. The term "and/or" particularly refers to one or more of the items mentioned before and after "and/or". For example, the phrase "item 1 and/or item 2" and similar phrases may refer to one or more of item 1 and item 2. The term "comprising" may mean "consisting of … …" in one embodiment, but may also mean "comprising at least the defined species and optionally one or more other species" in another embodiment.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

In addition to this, the device herein is also described during operation. As will be apparent to those skilled in the art, the present invention is not limited to the methods of operation or the apparatus in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention also applies to a device comprising one or more of the characterising features described in the description and/or shown in the attached drawings. The invention also applies to methods or processes comprising one or more of the characterising features described in the description and/or shown in the attached drawings.

The different aspects discussed in this patent may be combined in order to provide additional advantages. Further, it will be understood by those skilled in the art that embodiments may be combined, and that more than two embodiments may also be combined. Furthermore, some features may form the basis of one or more divisional applications.

Of course, one or more of the first (printable or printed) material and the second (printable or printed) material may contain a filler, such as T for the material(s)_gOr T_mGlass and fibers without (with) influence.