WO2017184002A1

WO2017184002A1 - A 3d printer working platform and a 3d printer containing such a work platform

Info

Publication number: WO2017184002A1
Application number: PCT/PL2017/050021
Authority: WO
Inventors: Piotr SYDOW; Tomasz MICHALSKI; Piotr MASLEJ; Piotr NAWROCKI; Kamil WOJTKO; Krzysztof KARDACH; Konrad SIERZPUTOWSKI
Original assignee: Omni3D Sp zoo
Current assignee: Omni3D Sp zoo
Priority date: 2016-04-18
Filing date: 2017-04-03
Publication date: 2017-10-26
Anticipated expiration: 2018-10-18
Also published as: PL416846A1; PL228959B1

Abstract

The object of the invention is a 3D printer print bed (10) having a support structure (5), comprising a support plate (5a), side walls (5b) and a support unit (5c), wherein at least three print bed (10) fittings (7) extend laterally from the support plate (5a), wherein at least one heating plate (2) is mounted in the support structure (5), with a heat transfer plate (3) mounted upon it, at least one print bed temperature sensor (21 ), and the build piate (1 ) of the print bed (10) is mounted on at least a part of the heating plate (2), wherein there is at least one fan (4) in the support unit (5c), and there is at least one through opening made. in the support plate (5a), corresponding to the position of the fan (4), whereas the side walls (5b) have a number of circulation openings (8). The object of the invention is also a 3D printer comprising such print bed (10).

Description

3D Printer Print Bed and 3D Printer Comprising the Same

The object of the invention is a 3D printer print bed and a 3D printer comprising the same, used for three-dimensional printing in the Fused Filament Fabrication technology, applied in Rapid Prototyping applications and custom production, finding application particularly in manufacturing industry, in medicine and prosthetics, education, garment design, in automotive industry, or in a broad range of consumer products and electronics.

3D printing is a process of fabrication of digitally designed three-dimensional objects. Printing in the Fused Filament Fabrication technology is effected by means of depositing consecutive layers into a predetermined shape. In general, the technology consists in delivering a synthetic thermoplastic materia! strand heated to a semi-liquid state to the print head for three-dimensional printing, moving spatially in three dimensions. The thermoplastic materials (half-products in 3D printing) used for printing in this technology, can be any kind of thermoplastic synthetic material in the form of a strand wound upon a spool, hereinafter referred to as the filament. Filament is applied either in layers or as points, and the deposition process is usually implemented in a chamber providing a temperature enabling thermal forming of the thermoplastic material. The local material temperature immediately upon leaving the nozzle is close to its melting temperature, or sometimes exceeds it. During 3D printing, a critical issue is to keep the appropriate conditions inside the build chamber, including the appropriate temperature in the build chamber and the temperature of the print bed. 3D printing can be used in various industries, e.g. architecture, fashion, medicine, electronics.

From US Patent No. US6722872 (B1 ) a three-dimensional modelling apparatus is known that enables fabrication of three-dimensional objects in a heated build chamber by dispensing modelling material from the dispensing head onto the base, in a pattern determined by control signals from a controller. The motion control components of the apparatus head are external to and thermally isolated from the build chamber by means of deform.abie thermal insulators forming the build chamber. Motion controls provide the movement of the head in the x-y plane. The application of deformable thermal insulators allowed the build chamber to be maintained at a relatively high temperature. In the solution referred to, the build chamber is surrounded by a heating duct that is formed of sheet metal and opens to the build chamber. Inside the heating duct, on one side of the chamber, there is a number of fin-strip heaters that provide heating the air in the heating duct, and the blower situated below provides the transport of the heated air into the build chamber. Such solution ensures maintaining the preset temperature inside the working chamber, but due to the application of hot air inlets into the build chamber, it does not ensure uniform distribution of temperature inside the chamber, and the air transported in the heating duct can cool down, whereby keeping the preset parameters becomes difficult. Furthermore, the presented apparatus for three-dimensional modelling does not provide heated print bed, which significantly affects the deterioration in the quality of the fabricated 3D objects.

American patent application US20 4048980 (A1 ) discloses an additive manufacturing system used for 3D printing. The system referred to comprises a chamber having chamber walls, wherein at least one of the chamber wails has a port extending therethrough and a heating mechanism configured to heat the chamber to one or more temperatures. The system also includes a print foundation and a print head for 3D printing on the print foundation in a layer-by-layer manner along a printing axis. The system also comprises a drive mechanism configured to index the print foundation along the printing axis such that while the print head prints the 3D object, the print foundation and at least a portion of the 3D object pass through the port and out of the heated chamber. The heating mechanism comprises heaters and air circulators to blow the heated air throughout the chamber in order to maintain the chamber, and in particular the area in the vicinity of the print head at appropriate printing conditions, i.e. increased ambient temperature, which is aimed at the reduction of distortions and curling of the printed material. In the solution referred to above, only the interior of the chamber has adjustable temperature that is additionally provided by the heater and the blower disposed either in the chamber wall, or in its upper internal surface, which does not ensure maintaining a uniform temperature throughout the volume of the chamber. Furthermore, heating of the print foundation itself is not provided for.

There is a 3D model HT500 by Kuhling&Kuhling available commercially. The 3D printer referred to above consists of a heated build chamber having a print bed inside, upon which consecutive layers of filament are deposited, being extruded from the print head. Vertical movement is provided through a movable print bed mounted on a spindle drive. Horizontal movement is provided by a gantry with belt drives upon which the print head is suspended. Heating of the build chamber is provided by the application of integrated resistance heating elements with fans providing air circulation inside the chamber. The print bed also has heating elements in the form of wired silicon heating pad. Two fans providing air circulation are disposed on a single plane at one of the chamber walls which does not provide appropriate circulation and uniform temperature distribution throughout the volume of the chamber. Furthermore, using separate heating elements for the print bed and the build chamber results in their multiplication which complicates the design of a 3D printer and increases its cost.

The technical problem faced by this invention is to propose such a 3D printer print bed that will provide heating the 3D printer print bed upper surface to the preset temperature, increasing the adhesion of the deposited layers to the surface of the print bed, will enable accelerated cooling of the print bed on demand, and will provided additional heating throughout the 3D printer build chamber, while keeping uniform temperature distribution throughout the volume of the build chamber, being at the same time a simple and single-module structure and shall allow to reduce the thickness of the whole print bed. Furthermore, it is desired to provide a 3D printer comprising such print bed, which will allow fabrication of three-dimensional objects, increasing their accuracy and quality, eliminating, at the same time, the internal stress in the printed object, the solution being simpler in design, limiting the number of components used, and being more reliable. Unexpectedly, the above technical problem has been solved by the present invention. The first object of the invention is a 3D printer print bed having a support structure, comprising a support plate, side walls and a support unit, with at least three print bed fittings extending laterally from the support plate, at least one heating plate being mounted in the support structure, having a heat transfer piate, at least one print bed temperature sensor, with the build plate of the print bed being mounted on at least a part of the heating plate, characterized in that there is at least one fan in the support unit, and there is at least one through port in the support plate, corresponding to the position of the fan, and the lateral waifs have a number of circulation holes. Preferably, there is a deflection plate fixed to the support unit, having at least one through port, corresponding to the position of the fan. Equally preferably, there is at least one heater under the support structure of the print bed, in the air duct connecting the space above the print bed and space beneath the print bed. In a preferred embodiment of the invention, the print bed is made of glass, stone or ceramics. In another preferred embodiment of the invention, the support unit has a substantially triangular shape in a parallel plane view, in another preferred embodiment of the invention, the circulation ports are dislocated in two opposite lateral walls. Preferably, the heating plate is powered with directional current voltage of about 380 V or alternating current voltage of about 230V.

The second object of the invention is a 3D printer for three-dimensional printing in fused filament fabrication technology, comprising a heated build chamber wherein a vertically movable print bed is situated on at least one linear drive, and a horizontally movable print head mounted on at least one linear drive (13), (14) in each of the two horizontal directions, characterized in that the print bed constitutes a print bed as defined in the first object of the invention. Preferably, the print bed is seated on three linear drives in the form of spindle drives. In a preferred embodiment of the invention, the print head is mounted on two linear drives in the form of spindle drives providing movement in one of the horizontal plane directions, an on one linear drive in the form of a spindle drive providing movement in the second of the horizontal plane directions. In another preferred embodiment of the invention, there is a temperature sensor installed inside the build chamber, !n another preferred embodiment of the invention, there is a mixing fan installed inside the build chamber.

The heated print bed of a 3D printer according to the present invention provides optimum adhesion of the printed object to the substrate due to heating the upper plate of the print bed. The heated buifd chamber with the printout cooling process control, on the other hand, minimizes and stabilizes the internal tension inside the printed object. The design of the print bed allows using the heat from the heating plate to raise and stabilize the temperature of the print bed and the build chamber of the 3D printer. The presented design ensures exact distribution of heat energy between the print bed and the build chamber. The application of temperature sensors integrated within the build chamber and in the print bed, and connected via the control system, allows for exact supervision and control both of the heating and the cooling process. The application of a mixing fan mounted in the build chamber additionally increases the uniformity of temperature distribution throughout the volume of the build chamber, which significantly affects the print quality. Utilization of the heating plate powered with high DC voltage in the print bed allowed to reduce the thickness of this element, thus the print bed itself, favorably influencing the compactness of the whole 3D printer. Whereas utilization of fans situated in the lower portion of the print bed provided dual use of the print bed itself, reducing the number of 3D printer components used, favorably influencing the cost effectiveness of the solution and its reliability. Exemplary embodiments of the invention have been presented in the drawings, wherein fig. 1 represents a 3D printer according to the first embodiment of the present invention in front view, fig. 2 represents the 3D printer of fig. 1 in axonometric projection, fig. 3 illustrates the print bed of the 3D printer according to the first embodiment of the present invention in axonometric projection, fig. 4 illustrates partial cross-section of the print bed of fig. 3, fig. 5 represents an axonometric projection of the first embodiment of the print bed mounted in the 3D printer chamber, fig. 6 represents a 3D printer according to the second embodiment of the present invention in front view, fig. 7 represents the 3D printer of fig. 6 in axonometric projection, fig. 8 illustrates the print bed of the 3D printer according to the second embodiment of the present invention in axonometric projection, fig. 9 illustrates partial cross-section of the print bed of fig. 8, fig. 10 represents an axonometric projection of the second embodiment of the print bed mounted in the 3D printer chamber.

Example 1 Figs. 1 and 2 illustrate an embodiment of a 3D printer for three-dimensional printing in the fused filament fabrication technology, according to the first embodiment of the present invention, in front and axonometric view, respectively. In general, the 3D printer has a heated build chamber 9 where the process of deposition of the fused thermoplastic material takes place. The build chamber 9 has side walls and an upper and a lower plates, all being made of a thermal insulation material which guarantees the thermal containment of the 3D printer build area and maintaining a stable printing environment with a preset temperature. The insulation consists of a thermal insulator about 10 mm thick attached to a sheet metal. There are three spindle drives 11 located in the build chamber 9, providing vertical movement of the print bed 10, upon the surface of which the three-dimensional print takes place. Utilization of spindle drives 11 for that purpose ensures the highest print accuracy since they are in principle resistant to high temperature effects, and in particular the temperature used in build chambers 9 (typically in the range of 70- 90°C). Furthermore, utilization of three independent spindle drives 11 enables very precise levelling of the print bed 10, which further improves the print accuracy. A 3D printer according to the present invention is a bridge structure, i.e. print head 12 is mounted on a frame structure providing movement of print head 12 in the horizontal plane of the 3D printer, whereas movement in the third direction, i.e. vertical, is implemented by vertically movable print bed 10. In this case, the printer head 12 is mounted on a linear spindle drive 14 ensuring the movement along one of the horizontal plane directions, and two linear spindle drives 13 providing movement in the second horizontal plane direction. Furthermore, the motors of linear spindle drives 13 are covered by the drive housing 17 in order to protect them against high temperatures. Motors 18 of these linear drives 13 are arranged outside the build chamber 9 in order to reduce the impact of high temperatures upon these components, thus increasing the reliability and durability of the entire system. Inside the build chamber 9 of the 3D printer, there is a print bed 10, the first embodiment of which has been illustrated in detail in fig. 3 and fig. 4.

The print bed 10 is mounted inside the printer build chamber 9 in such a way as to enable its precise movement up and down. The print bed 10 or the 3D printer has a support structure 5 comprising a support plate 5a, side walls 5b and the support unit 5c. There are three fixtures 7 extending from the support structure in lateral directions, which connect with the linear spindle drives 11 in the build chamber 9. Therefore, the support unit 5c in the parallel plane projection assumes a substantially triangular shape, wherein the apexes of the shape constitute fixtures 7 of the print bed 10. The support structure 5 contains the heating plate 2 with a heat transfer plate 3 mounted upon it, and a print bed temperature sensor 21. The print plate 1 of the print bed 10, upon which the material from the print head 12 is deposited, is mounted on the print plate temperature sensor 21 and on the heat transfer plate 3. The print plate 1 is most preferably made of glass and forms the basis for creation of three-dimensional models. Alternatively, the print piate 1 can be made of other materials suitable for that purpose, like stone or ceramics. The lowest layer of the printed model must be glued to the print plate 1. The application of increased temperature for the print bed 10, actually for the print plate 1 , favors increased adhesion phenomena between glass and the deposited material. In order to provide the minimum height of the print bed 10, a heating plate 2 was implemented, powered with DC voltage of about 380 V or AC voltage of about 230V. This optimizes the height of the print bed while maintaining relatively high power (about 1800 W) output. There are two fans 4 in the support unit 5c, situated on the underside of the print bed 10, whereas in the support piate 5a, there are two through openings corresponding to the position of the fans 4 (substantially coaxial), which provides the air flow from the build chamber 9 under the print bed 10 to the build chamber 9 over the print bed 10. There are circulation openings 8 in the side walls 5b on two opposite sides, which the air heated in the heating piate 2 and drawn by the fans 4 is forced through. For the functional purposes, there is a control port 19 for fans 4 and the temperature sensor readout 21 , and the power supply port 20 of the heating plate 2 on the side wall of the support unit 5c. As illustrated in fig. 5, in the build chamber 9 of the 3D printer, there is a chamber temperature sensor 15 mounted on one of the walls, whose function is to read the temperature inside the build chamber 9, in particular over the surface of the print bed 10. Inside the build chamber 9, there is also a mixing fan 16 that provides uniform distribution of the heated air throughout the building space, that is throughout the whole volume of the build chamber 9.

It has to be noted that with the application of subsequent layers of material, its contraction occurs (in case of lack of the build chamber 9 and the print bed 10 temperature adjustment and stabilization), which is manifested by model cracking, its deformation and loss of adhesion to the print bed 10. In order to prevent that, the temperature in the build chamber 9 has to be increased to the one appropriate for the specific material (filament). This was achieved by heat recovery from the lower surface of the heating plate 2. The air is pumped to the heating plate 2 that after heating is transferred to the build chamber 9 in order to heat the latter. The adjustment function is performed by two fans 4. When they are stopped, the print bed 10 is heated, and when they operate, they pump hot air into the build chamber 9. Whereas during the operation of fans 4 and the heating plate 2 being switched off, accelerated cooling of the print bed 10 and the build chamber 9 takes place. Both the temperature of the print bed 10, and the temperature of the build chamber 9 are adjusted and stabilized by means of an electronic control system {not illustrated), based on the data from the print bed sensor 21 and the chamber sensor 15. The temperature values can be freely changed by the user and programmed into the printing process. However, the print bed 0 temperature value acts as a priority. The preset value of the build chamber 9 will be always lower than the temperature of the print bed 10, which ensures optimum conditions for printing models. The control system also provides control of the fan 16 mixing the air inside the build chamber 9 and the production of voltage to power the heating plate 2.

Example 2

Figs. 6 and 7 present the second embodiment of a 3D printer for three- dimensional printing in the fused filament fabrication technology seen, respectively, from the front and in the axonometric projection. In general, the 3D printer according to the second embodiment is structurally similar to the 3D printer according to the first embodiment, and therefore the same numerical symbols are used to reference to the same or similar components of the 3D printer. One of the more significant differences between the presented embodiments of 3D printers is the design of the print bed 10 implemented inside, as illustrated in figs. 8-10.

Like in the previous embodiment, the print bed 10 is mounted inside the printer build chamber 9 in such a way as to enable its precise movement up and down. The print bed 10 or the 3D printer has a support structure 5 comprising a support plate 5a, side walls 5b and the support unit 5c. There are three fixtures 7 extending from the support structure in lateral directions, which connect with the linear spindle drives 1 in the build chamber 9. The support structure 5 contains the heating plate 2 with a heat transfer plate 3 mounted upon it, and a platform temperature sensor 21. The print plate 1 of the print bed 10, upon which the material from the print head 12 is deposited, is mounted on the print plate temperature sensor 21 and on the heat transfer plate 3. The print plate 1 is most preferably made of glass and forms the basis for creation of three-dimensional models. Alternatively, the print plate 1 can be made of other materials suitable for that purpose, like stone or ceramics. The lowest layer of the printed model must be glued to the print plate 1. The application of increased temperature for the print bed 10, actually for the print plate 1 , favors increased adhesion phenomena between glass and the deposited material. In this embodiment, a heating plate 2 has been applied in the print bed, powered with AC voltage of about 230 V or DC voltage of about 380 V, thus reaching both relatively high power of about 1800 W, and reducing the height of the whole print bed 10 structure. Furthermore, in the presented embodiment, the support structure 5 has the support unit 5c attached, which in turn has a deflector plate 22 attached, whose function is to separate and guide the streams of air taken out from and returned back to the build chamber. The deflector plate 22 is attached to the support plate 5a by means of a support unit 5c. The support unit 5c has a series of circulation openings 8, while the deflector plate 22 houses a fan 4 corresponding to the location of heater 23 that carries out the heating of the air inside the chamber. This provides taking the air from above the print bed 10, heating the same and transferring it back to the build chamber 9. The openings in the support unit 5c are situated on each side of the print bed 10, so the air is passed, heated under the print bed 10, and then, by means of the fan 4, blown into the build chamber 9. In this embodiment the mixing fan 16 located inside of the build chamber 9 was removed, and the air circulation is provided by the fan 4 situated under the print bed 10, and whose construction elements are covered by the fan cover 25. There is an additional separation piate 24 between the fan cover 25 and the support structure 5 of the print bed 10. As illustrated in fig. 10, in the build chamber 9 of the 3D printer, there is a chamber temperature sensor 15 mounted on one of the walls, whose function is to read the temperature inside the build chamber 9, in particular over the surface of the print bed 10. The fan 4 situated under the print bed 10, besides providing heated air into the chamber 9, also provides a homogeneous distribution of air throughout the build chamber 9 volume. There is a separation plate 12 mounted from below to the print bed, whose dimensions limit the space of the build chamber in the horizontal plane, whereas the volume of the air in the chamber changes together with the movement of the bed 10. There is a fan engine cover 13 mounted onto the separation plate 12 from below.

Claims

1. The print bed (10) of the 3D printer comprising a support structure (5), comprising a support plate (5a), side wails (5b) and a support unit (5c), wherein at least three print bed (10) fittings (7) extend laterally from the support plate (5a), wherein at ieast one heating plate (2) is mounted in the support structure (5), with a heat transfer piate (3) mounted upon it, at Ieast one print bed temperature sensor (21 ), and the build plate (1 ) of the print bed (10) is mounted on at Ieast a part of the heating plate (2), characterized in that there is at Ieast one fan (4) in the support unit (5c), and there is at Ieast one through opening made in the support plate (5a), corresponding to the position of the fan (4), whereas the side walls (5b) have a number of circulation openings (8).

2. The print bed according to claim 1 , characterized in that there is a deflection p!ate (22) fixed to the support unit (5c), having at Ieast one through opening, corresponding to the position of the fan (4),

3. The print bed according to claim 1 or 2, characterized in that there is at Ieast one heater (23) situated within the space between the print bed (10) support structure (5) and the separation plate (12)

4. The print bed of any one of claims 1 to 3, characterized in that the build plate (1 ) is made of glass, stone or ceramics.

5. The print bed of any one of claims 1 to 4, characterized in that the support unit (5c) in the parallel plane projection assumes a substantially triangular shape,

6. The print bed of any one of claims 1 to 5, characterized in that the circulation openings (8) are located in two opposite side walls (5b).

7. The print bed of any one of claims 1 to 6, characterized in that the heating plate (2) is powered with DC voltage of about 380V or AC voltage of about 230V.

8. A 3D printer for three-dimensional printing in fused filament fabrication technology, comprising a heated build chamber (9) having a vertically movable print bed (10) mounted on at least one linear drive (11 ) and a horizontally movable print head (12) mounted on at least one linear drive (13), (14) in each of the two horizontal directions installed inside, characterized in that the print bed constitutes the print bed (10) as defined in any of claims from 1 through 7.

9. 3D printer according to claim 8, characterized in that the print bed

(10) is seated on three linear drives (11 ) in the form of spindle drives. 0. A 3D printer according to claim 8 or 9, characterized in that the print head (12) is mounted on two linear drives (13) in the form of spindle drives providing movement in one of the horizontal plane directions, and on one linear drive (14) in the form of a spindle drive providing movement in the second of the horizontal plane directions.

11. The 3D printer of any one of claims 8 to 10, characterized in that there is a chamber temperature sensor (15) inside the build chamber (9).

12. The 3D printer of any one of claims 8 to 11 , characterized in that there is a mixing fan (16) inside the build chamber (9).