Apparatus for additive fabrication of a three-dimensional (3D) object

Abstract

The invention relates to an apparatus for additive fabrication of a three-dimensional (3D) object, comprising a work table adapted for supporting at least a portion of the 3D object, wherein the work table has a work table surface and the apparatus comprises at least one print head. The invention also relates to a method for additive fabrication of a three-dimensional (3D) object.

Description

[0001] Title: Apparatus for additive fabrication of a three-dimensional (3D) object

[0002] Description:

[0003] The invention relates to an apparatus for additive fabrication of a three- dimensional (3D) object, comprising a work table adapted for supporting at least a portion of the 3D object, wherein the work table has a work table surface and the apparatus comprises at least one print head.

[0004] The invention also relates to a method for additive fabrication of a three- dimensional (3D) object.

[0005] US 2023 / 0129285 A1 discloses an apparatus comprising a gantry arrangement with a print head and a work table which is moveably supported in the apparatus such that the work table can be moved after printing material with the print head. The known apparatus further comprises a support member or rail for slidingly supporting a bottom surface of a growing printed part. A drawback of the known apparatus is that a sliding object support has a risk of damaging the printed part. In addition, a vertical distance between the work table and the rail cannot be changed in the known apparatus, such that the growing printed object requires a predefined bottom surface to be sufficiently supported which imposes restrictions on the shape of the printed object.

[0006] It is an object of the present invention to provide an apparatus for additive fabrication of a three-dimensional (3D) object which provides improved support and / or provides more flexibility regarding the shape of the printed object.

[0007] This object is achieved with an apparatus as claimed in claim 1.

[0008] The apparatus for additive fabrication of a three-dimensional (3D) object, comprises: a work table adapted for supporting at least a portion of the 3D object, wherein the work table has a work table surface; at least one print head, wherein the print head is configured for depositing at least a first material layer of the object on a print surface which is inclined, in particular extends substantially transversely, to the work table surface which faces the at least one print head.

[0009] The work table comprises multiple supporting members, each supporting member comprises a driving mechanism and an object supporting member end adapted to be moved by means of the driving mechanism from a first position to a second object supporting position and vice versa, wherein in the second object supporting position the distance between the object supporting member end and the work table surface is larger than in the first position.

[0010] The apparatus of this disclosure does not require a moveable work table with relatively complex movement control, for example during printing. Such a less complex work table of the apparatus of this disclosure brings substantial benefits, such as simplicity, cost-effectiveness and reliability. The multiple support members of the apparatus provide a highly flexible 3D printing apparatus designed for maximal shaping versatility. In addition, the multiple support members reduce significantly the deformation or sagging (gravity) of layers, particularly in overhanging sections of the printed object. The multiple support members also provide minimal or even no restrictions on the shape of the object to be printed and (to be) supported, such that the apparatus of this disclosure provides relatively much flexibility and freedom regarding the design of the object to be printed. The multiple supporting members may be arranged in a grid-arrangement, i.e. in multiple series of rows and columns. The grid-arrangement may have a length longer than a width of the grid. By means of the grid-arrangement, it is possible by means of the multiple supporting members to provide maximum design freedom regarding printing and optimal support for the object being printed. The driving mechanism is adapted to stationary maintain the object supporting member end in the second object supporting position at least during the printing process, such that the non-moving (non-sliding) object supporting member end in the second object supporting position with respect to the object being printed has no, or at least minimal, impact on the print quality of the object.

[0011] The at least one print head of the apparatus is further configured for printing on an inclined surface with respect to the work table surface. The work table surface may be for example a substantially horizontal extending work table surface, wherein the inclined surface may be substantially transversely extending with respect to the horizontal work table surface. For example, an angle equal to or larger than 45 degrees and equal to or smaller than 135 degrees, preferably the angle is 65-115 degrees, more preferably 80-100 degrees between the inclined surface and the work table surface makes the apparatus of this disclosure adapted for so-called “vertical bed printing” of at least the first material layer of the object, i.e, the print head prints on a substantially vertically extending bed. The inclined surface may be formed by a support structure, for example a (removable) support structure positioned on the work table surface, and / or the support structure may be an at least partly printed support structure defining the inclined surface for printing the three-dimensional (3D) object. The support structure may be removed after printing. The at least partly printed support structure may be manufactured by the apparatus. An inclined surface provided by the (temporary) support structure makes “vertical bed printing” possible. In “vertical bed printing” the main printing direction of the print head is normally more in the horizontal direction (x-, or y-direction) than in the vertical or gravity direction (z-direction). With “vertical bed printing”, it is preferred to work above the work table surface to prevent the 3D printing head, such as for example its nozzle, from touching the work table surface. As a result, the printed object manufactured with “vertical bed printing” has substantially no contact with the work table surface and / or substantially suspends or floats above the work table surface which eventually may result in the problem of sagging / hanging. Hence, supporting members need to ensure stability of “vertical bed printing” without compromising the finish of the final printed object. The advantages of multiple support members of the apparatus are that the support members are adapted to be self-regulating by means of a control unit to be discussed below and are adapted to move with minimal force such that the supporting members have no or at least reduced impact on the finish of the final printed object. In addition, each support member is configured to lock (stationary maintain) upon touching the printed object for optimal support of a printed object. As indicated above, such an object printed with “vertical bed printing” may normally extend more in a horizontal direction with its (largest) horizontal dimension than its vertical dimension as the final object is (still) supported by the supporting members, but it is no requirement of “vertical bed printing” in that it is also possible by means of the apparatus of this disclosure to print an object having a larger vertical dimension than one of the two horizontal dimensions (length and width). In other words, the apparatus of this disclosure is configured for vertical bed printing.

[0012] The work table may comprise a first section defining the work table surface and a second section defining the print surface for receiving the at least one first material layer, wherein the print surface and the work table surface extend substantially transversely with respect to each other, such as including an angle between the print surface and the work table surface equal to or larger than 45 degrees and equal to or smaller than 135 degrees, preferably the angle is 65-115 degrees, more preferably 80- 100 degrees.

[0013] The apparatus may further comprises a control unit adapted to vary the distance between the object supporting member end and the work table surface in the second object supporting position depending on the design of a lower surface of the object being printed. The control unit is communicating with the driving mechanisms of the supporting members. The height or vertical distance between the work table surface and the object being printed may vary between the supporting members for providing optimal support, such that control unit controls the driving mechanism of each supporting element individually such that it is possible to obtain second object supporting positions with different heights with respect to the work table surface. The control unit may be configured to communicate with a sensor system to obtain the optimal height for each support element and / or may be configured to use data (for example from CAD data) to obtain the predetermined optimal height for each support element.

[0014] In one aspect, the apparatus comprises a control device configured for controlling the movement and the printing process of the at least one print head. The control device may comprises the control unit of this disclosure, but it is also possible that the control device and the control unit are spaced and are configured to communicate with each other for controlling the at least one print head and the driving mechanisms of the apparatus. The control device or the control unit communicating with the control device may be configured to activate the driving mechanism of each supporting member simultaneously or after at least one material layer to be supported by one of the supporting members is deposited above the at least one supporting member. In this manner the supporting members do not cause any hindrance for the printing process of the print head, in particular the “vertical bed printing” process. The driving mechanism may be activated simultaneously if the movement of the respective supporting member provides no hindrance for the print head or the print process to be performed by the print head.

[0015] The printing head may be arranged on a robot arm with robotic arm control. A robotic arm may be equipped with specialized end-effector (like an extruder). A robotic arm based apparatus enables printing of large structures (having at least one dimension of 1 meter). The robotic arm control allows movement in multiple axes, allowing for greater freedom in printing geometries, in particular relatively complex geometries as a result of the ability of robotic arms to move in complex paths allowing for the creation of intricate and organic shapes that might be challenging for other 3D printers, such as a gantry based 3D printing apparatus. Design integration of a robot based apparatus is seamless with computer-aided design (such as CAD) software, which generates the paths the robotic arm will follow. Further, simulation tools can predict print outcomes and optimize parameters before actual printing. A further robot based apparatus advantage with respect to a gantry based apparatus is that a robot arm has more degrees of freedom with respect to the height of the object being printed.

[0016] The robot arm may be part of an arrangement comprising a track along the work table surface, wherein the robot arm is movably arranged on the track.

[0017] This disclosure also relates to a method for additive fabrication of a three- dimensional (3D) object by means of an apparatus as disclosed herein. For brevity and to avoid unnecessary repetition, reference is made to the advantages as explained with respect to the apparatus as described in this disclosure. In addition, the at least one print head may be depositing at least the first printing material layer having a width, length and a thickness, on the printing surface, wherein the length of the first printing material layer is defined by means of a printing direction of the at least one print head, wherein a direction defined by the layer thickness extends substantially parallel to the horizontal, wherein substantially parallel includes an angle of 45-135 degrees with the horizontal, preferably between 65 - 115 degrees with the horizontal, more preferably between 80-100 degrees with the horizontal.

[0018] In the method, the object may be printed by means of “vertical bed printing”. In “vertical bed printing” the object is mainly being printed above and at a distance of the work table surface. Hence, it is possible to print an object in the method of this disclosure without contact between the work table surface and the object. Hence, the apparatus of this disclosure is adapted to print an object in the method of this disclosure without contact between the work table surface and the object.

[0019] Vertical bed printing is a technique where the print bed, or the platform on which the printed object is built, is oriented more vertically rather than the traditional horizontal orientation. In the vertical bed setup of the apparatus, the way gravity interacts with the printing process is changed, as layers are built up in a vertical plane rather than stacking horizontally, wherein gravity acts differently on the extruded material and may cause (eventually) the extruded filament to sag or deform. It is for example possible to use cooling systems to ensure that the material solidifies correctly as it is extruded in a vertical orientation. Vertical bed printing is space efficient, because vertical beds can save space in manufacturing environments where floor space is limited and multiple apparatuses can be stacked or arranged more compactly and / or relatively large objects (minimum dimensions at least 1 meter) can be printed in a constrained floor space. Further, vertical bed printing may improve inter-layer adhesion due to the altered influence of gravity, which may result in stronger parts, and / or reduction of warping as the thermal gradients may be different compared to horizontal bed printing.

[0020] It is to be understood that both the foregoing general description and the following detailed description present various embodiments of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed.

[0021] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.

[0022] The apparatus and method will now be explained in more detail with reference to the appended drawings, in which:

[0023] Figures 1a, b show a schematic view of a first embodiment of an apparatus for additive fabrication of a three-dimensional (3D) object;

[0024] Figures 2a, b show diagrammatically parts of a second embodiment of an apparatus for additive fabrication of a three-dimensional (3D) object;

[0025] Figures 3a-c show diagrammatically parts of the first embodiment in a side view and variations of a control scheme for a driving mechanism of the apparatus;

[0026] Figure 4a, b show diagrammatically variants of a fluid actuator of a driving mechanism of the apparatus;

[0027] Figures 5a-c show diagrammatically other variants of an actuator of a driving mechanism of the apparatus. The apparatus 10 for additive fabrication of a three-dimensional (3D) object will now be described more fully hereinafter with reference to the accompanying drawings in which exemplary embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the representative embodiments set forth herein. The exemplary embodiments are provided so that this disclosure will be both thorough and complete, and will fully convey the scope of the invention and enable one of ordinary skill in the art to make, use and practice the invention. For example, the figures 1a,b are primarily used to illustrate an example of a printing apparatus 10. However, the invention regarding the support concept and inclined printing as defined in this disclosure is also applicable to other types of 3D printers, such as gantry, cartesian, delta 3D printers, etcetera. The track 11 as shown in figure 1a is adapted for moving the robot arrangement 70 in the length direction indicated with L in figure 1a. However, it is also possible to use a robotic based apparatus 10 without a track 11 or with a different moving mechanism moving the robot arrangement 70 in the length direction indicated with L in figure 1a.

[0028] In the embodiment as shown the robot arrangement 70 and / or the track 11 comprise a drive unit to move the robot arrangement 70 in the length direction L along the track 11 and work table 20 to be discussed below.

[0029] Like reference numbers refer to like elements throughout the various drawings.

[0030] Figure 1 a shows a perspective view of the robotic arm based printing apparatus 10 with the track 11 and the work table 20. Figure 1 b shows an enlarged view of figure 1a (see dotted circle indicated with A in figure 1a) showing a print head 30 of the apparatus 10. The print head 30 is an extrusion based print head 30.

[0031] The apparatus 10 for additive fabrication of a three-dimensional (3D) object 15, comprises a work table 20; 20’ adapted for supporting at least a portion of the 3D object 15, wherein the work table 20; 20’ has a work table surface 22; 22’. The apparatus 10 further comprises at least one print head 30. The print head 30 is configured for depositing at least a first material layer of the object on a print surface 24; 24’ which is inclined, in particular extends substantially transversely, to the work table surface 22; 22’ facing the at least one print head 30.

[0032] The work table 20; 20’ comprises multiple supporting members 26; 26’, each supporting member 26; 26’ comprises a driving mechanism 28; 28’ (figs. 3b, c) and an object supporting member end 27; 27’ adapted to be moved by means of the driving mechanism 28; 28’ from a first position (identified with I in fig. 2b or 3a) to a second object supporting position (identified with II in 2b or fig. 3a) and vice versa, wherein in the second object supporting position II the distance d (fig. 3a) between the object supporting member end 27; 27’ and the work table surface 22; 22’ is larger than in the first position I.

[0033] The work table 20; 20’ as shown in the figures comprises a first section or a first work table 20a; 20a’ defining the work table surface 22; 22’ and a second section or a second work table 20b; 20b’ defining the print surface 24; 24’ for receiving the at least one first material layer, wherein the print surface and the work table surface extend substantially transversely with respect to each other, as shown in the figures, i.e. the angle a between the print surface 24; 24’ and the work table surface 22; 22’ is approximately 90 degrees. As explained in this disclosure the angle a may vary between 45-135 degrees.

[0034] As shown in the figures, the first work table 20a; 20a’ and the second work table 20b; 20b’ are stationary arranged in the apparatus 10, more particular the stationary first work table 20a; 20a’ and the stationary second work table 20b; 20b’ are fixed to each other or are formed as a one-piece component (not shown) without any joints, seams, or separate parts joined together, preferably made from a single piece of material.

[0035] The work table surface 22; 22’has a width w (fig. 1b) and length dimension L (fig. 1a), wherein the length dimension L is greater than the width dimension w, for example at least two times greater or at least three times greater. As indicated by double arrow z in fig. 3a, the second work table 20b; 20b’ has a vertical orientation, wherein the height (z-direction) of the worktable 20; 20’ is substantially defined by the second work table 20b; 20b’ and the length L and width w of the worktable 20; 20’ is substantially defined by the first work table 20a; 20a’.

[0036] The multiple supporting members 26; 26’ of the work table 20; 20’ are arranged in a grid-arrangement, wherein the grid-arrangement as shown has a length L longer than a width w of the grid. The multiple supporting members 26; 26’ are provided at least partially in the first work table 20a; 20a’, i.e. the work table surface 22 is provided with holes through which the supporting member can be moved in a linear manner as will be explained below. Each supporting member 26, 26’ and associated driving mechanism have to be adapted to lock in place, i.e. at the optimal support height (z-direction), with respect to the work table surface 22; 22’ and to stationary support the weight of the printed object 15. Movement in the locked position due to the weight of the object 15 is undesired. In the embodiment shown in figure 2a the driving mechanism of the supporting member 26’ comprises at least one pivotable lever mechanism 128 for moving or rotating the object supporting member end 27’ at least between the first and second object supporting positions. The lever mechanism 128 is adapted to stationary maintain the end 27’ in the second object supporting position for optimal support of the object 15 with no or minimal impact on the object 15. The pivotable lever mechanisms 128 are substantially provided on the work table surface 22’, i.e. in the first object supporting position the end 27 lies on the work table surface 22’.

[0037] The apparatus 10 comprises a control unit 50 adapted to vary the distance between the object supporting member end 27 and the work table surface 22; 22’ in the second object supporting position depending on the design of a lower surface of the object being printed, see for example figures 2b and 3 for a varying distance (in the z-direction) between the lower surface of the object 15 and the work table surface 22; 22’. The apparatus 10 further comprises a control device 60 configured to activate the driving mechanism 28; 28’ of each supporting member 26 simultaneously or after at least one material layer to be supported by one of the supporting members is deposited by means of the print head 30 above the at least one supporting member. The control device 60 and the control unit 50 may also be incorporated in one physical device (not shown). The control device 60 associated to the robot arrangement 70 is further configured for controlling the movement and printing process of the at least one print head 30. In the first position, the object supporting member end 27 does not protrude with respect to the work table surface 22, such there can be no hindrance for the print head 30 during the printing process.

[0038] In the embodiment as shown in figures 1a, b and 3a-5c, the driving mechanism comprises at least one linear actuator adapted for linear movement of the object supporting member end 27 between the first and second object supporting position.

[0039] The supporting member 26 as shown in figure 5b comprises an electric driving mechanism 228, i.e. a mechanical actuator, in particular an electro-mechanical actuator. The supporting member 26 as shown in figure 5c comprises a driving mechanism 328 converting rotational motion into linear motion of the supporting member, wherein the driving mechanism 328 comprises a motor (not shown). The driving mechanism 328 is a mechanical actuator. Figure 5a uses a telescopic driving mechanism 428 for movement of the supporting member 26, wherein the telescopic driving mechanism 428 may comprises an electric motor or is driven by means of a hydraulic drive to be discussed below in more detail. Each driving mechanism 228; 328; 428 is adapted to stationary maintain or “lock” the end 27 in the second object supporting position for optimal support of the object 15 with no or minimal impact on the object 15. Although the figures are explained by means of a hydraulic actuator, it is also possible to use a fluid actuator such as a pneumatic actuator as a pneumatic drive. The hydraulic actuator 28; 28’ uses at least one liquid, which is an incompressible liquid (normally oil), to transmit power. Common hydraulic include liquids like oil, water, water solutions, and / or synthetic liquids. The incompressibility of liquids in the hydraulic actuator compared to the pneumatic actuator allows for precise control and high force transmission.

[0040] With reference to the supporting member 26 using a hydraulic actuator 28; 28’ upward movement of the supporting members is facilitated by a hydraulic liquid (hereafter oil) similar to a hydraulic cylinder 40.

[0041] The fluid actuator 28; 28’ comprises a fluid control mechanism to control movement of the object supporting end 27 of the supporting member 26. The fluid control mechanism comprises at least one way valve 42 and a pneumatic controller 41 which is configured to switch the at least one way valve 42 between a first state preventing fluid backflow from a driving chamber 43 of the supporting element 26 and a second state allowing backflow from the driving chamber 43 of the at least one fluid actuator. In the second state it is possible to reduce the distance between the object supporting member end 27 and the work table support surface 22. The fluid control mechanism has a fluid line 52, 52a between the at least one way valve 42 and the pneumatic controller 41 and fluid line 54 between the pneumatic controller 41 and reservoir 46 which is for example filled with oil 48. The fluid control mechanism further has a fluid line 52, 52b between the pneumatic controller 41 and a return chamber 44. The fluid actuator 28; 28’ further comprises a fluid line 56 between the reservoir 46 and the driving chamber 43. This fluid line 56 comprises the at least one way valve 42. By means of such a fluid control mechanism accurate fluid control is possible for precise movement of end 27 and to provide optimal support by means of the end 27 to the 3D object printed or being printed by means of the at least one print head 30 of the apparatus. The first state has a first sub state allowing filling of the chamber 43 of the at least one fluid actuator 28; 28’ to linearly move the object supporting member end 27 to an object supporting position and a second sub state for maintaining the object supporting member end 27 in an object support position. In the second sub state, the fluid control mechanism is adapted to provide no filling of the chamber 43 through fluid line 56 and to prevent backflow from the chamber 43 through fluid line 56 such that end 27 is maintained at the desired support position without movement as a result of the load of the object. The desired support position may be a predetermined support position. In the second state the pneumatic controller 41 is configured to supply a gas to the return chamber 44 to promote backflow from chamber 43 for reducing the distance between the object supporting member end 27 and the work table support surface 22. The pneumatic controller 41 may further be configured to control at least one fluid reservoir 46 of the at least one fluid actuator 28; 28’ such as to fill the chamber 43 and to move the end 27 upwards to its object supporting position and to maintain (“lock”) the end 27 there. An advantage of a pneumatic controller 41 compared to a hydraulic regulator 41 is that the fluid supply to chamber 43 and fluid discharge from chamber 43 can be controlled more accurately.

[0042] As an example: By means of the pneumatic controller 41 of the apparatus 10 oil 48 from a reservoir 46 is fed to the chamber 43 of the cylinder 40. A one way check valve 42 which is positioned in the oil feed line 56 to the cylinder 40, ensures that oil can enter the drive chamber 43 of the cylinder 40 but cannot exit this drive chamber 43, i.e. , the one way check valve 42 in the first state prevents backflow, such that the object supporting member end 27 can be moved upwards to the second object supporting position and locked (stationary maintained) in this second position supporting the object during printing by stopping feeding oil 48 to the drive chamber and maintaining the one way check valve 42 in the first state preventing backflow. The one way check valve 42 is controlled by the pneumatic controller 41. The oil feed to chamber 43 is controlled by the pneumatic controller 41 by means of controlling gas through line 54 connected to the oil reservoir 46. In the second sub state of the one way valve it is impossible for the supporting element 26 with piston to be pressed down in the second object supporting position, as the oil 48 inside chamber 43 is incompressible and backflow from chamber 43 is excluded by means of the one way valve 42. To lower the supporting element 26 with piston from the second object supporting position to or towards the first position, the one-way valve 42 is deactivated by means of the pneumatic controller 41 through gas through line 52, 52a, allowing the oil to flow back from chamber 43 to reservoir 46. Compressed air may be provided by the pneumatic controller 41 and be introduced in the chamber 44 of the cylinder 40. The air pressure in the top chamber 44 can be used to force out the oil of the chamber 43, causing the cylinder to lower its position towards the first position in a reliable and relatively fast manner. In addition, or alternatively to compressed air, a spring 80 (fig. 4b) arranged in the chamber 44 can be used to force oil out of the chamber 43. The pneumatic controller 41 is in communication with a control unit 50 of the apparatus. The control unit 50 is adapted to control the pneumatic controller 41 to vary the distance between the object supporting member end and the work table surface in the second object supporting position for example depending on the design of a lower surface of the object being printed, the pneumatic controller 41 may further be in communication with the control device 60 of the apparatus 10.

[0043] In figure 3c a variation is shown in which one pneumatic controller 41’ is controlling the movement of multiple hydraulic actuators 28’, i.e. three hydraulic actuator 28’ as shown.

[0044] Pressure regulators may be added and / or sensors may be added in the hydraulic actuators 28; 28’ to gain extra information about the status of hydraulic actuator positions, valve positions, line pressure / flow and / or reservoir level.

Claims

CLAIMS1. An apparatus for additive fabrication of a three-dimensional (3D) object, comprising: a work table adapted for supporting at least a portion of the 3D object, wherein the work table has a work table surface; at least one print head; wherein the print head is configured for depositing at least a first material layer of the object on a print surface which is inclined, in particular extends substantially transversely, to the work table surface which faces the at least one print head, wherein the work table comprises multiple supporting members, each supporting member comprises a driving mechanism and an object supporting member end adapted to be moved by means of the driving mechanism from a first position to a second object supporting position and vice versa, wherein in the second object supporting position the distance between the object supporting member end and the work table surface is larger than in the first position.

2. The apparatus according to claim 1 , wherein the work table comprises a first section defining the work table surface and a second section defining the print surface for receiving the at least one first material layer, wherein the print surface and the work table surface extend substantially transversely with respect to each other, such as including an angle between the print surface and the work table surface equal to or larger than 45 degrees and equal to or smaller than 135 degrees, preferably the angle is 65-115 degrees, more preferably 80-100 degrees.

3. The apparatus according to claim 1 or 2, wherein the apparatus further comprises a control unit adapted to vary the distance between the object supporting member end and the work table surface in the second object supporting position depending on the design of a lower surface of the object being printed.

4. The apparatus according to any of the preceding claims, wherein the driving mechanism comprises at least one pivotable lever mechanism for moving the object supporting member end between the first and second object supporting position.

5. The apparatus according to any of the preceding claims 1-3, wherein the driving mechanism comprises at least one linear actuator adapted for linear movement of the object supporting member end between the first and second object supporting position.

6. The apparatus according to claim 5, wherein the least one linear actuator is a mechanical actuator including an electro-mechanical actuator.

7. The apparatus according to claim 5, wherein the least one linear actuator is a fluid actuator including a hydraulic actuator and / or a pneumatic actuator.

8. The apparatus according to claim 7, wherein the fluid actuator comprises a fluid control mechanism to control movement of the object supporting member end.

9. The apparatus according to claim 8, wherein the fluid control mechanism comprises at least one one-way valve and a pneumatic controller which is configured to switch the at least one way valve between a first state preventing fluid backflow from a drive chamber of the fluid actuator and a second state allowing backflow from the drive chamber.

10. The apparatus according to claim 9, wherein the first state has a first sub state allowing filling of the drive chamber to linearly move the object supporting member end to an object supporting position and a second sub state maintaining the object supporting member end in the second object supporting position.

11. The apparatus according to claim 9 or 10, wherein in the second state the pneumatic controller is configured to supply a gas to a return chamber to promote backflow from the drive chamber.

12. The apparatus according to claim 9, 10 or 11 , wherein the pneumatic controller is configured to control at least one fluid reservoir of the fluid actuator, wherein in a fluid line between the at least one fluid reservoir and the drive chamber the one way valve is provided.

13. The apparatus according to any of the claims 8-12, wherein the fluid actuator is a hydraulic actuator.

14. The apparatus according to any of the preceding claims, wherein the apparatus comprises a control device configured for controlling the movement and printing process of the at least one print head.

15. The apparatus according to claim 14, wherein the control device is further configured to activate the driving mechanism of each supporting member simultaneously or after at least one material layer to be supported by one of the supporting members is deposited above the at least one supporting member.

16. The apparatus according to claim 3 and 14, or 3 and 15, wherein the control device comprises the control unit or is adapted to communicate with the control unit.

17. The apparatus according to any of the preceding claims, wherein the work table comprises a first work table comprising the work table surface and a second work table comprising the print surface, wherein the first work table and / or the second work table is / are stationary and / or the first work table and the second work table are fixed to each other.

18. The apparatus according to any of the preceding claims, wherein the work table surface has a width and length dimension, wherein the length dimension is greater than the width dimension, preferably at least two times greater, more preferably at least three times greater.

19. The apparatus according to any of the preceding claims, wherein the multiple supporting members are arranged in a grid-arrangement, preferably the gridarrangement has a length longer than a width of the grid.

20. The apparatus according to any of the preceding claims, wherein the printing head is arranged on a robot arm with robotic arm control.

21. The apparatus according to claim 20, wherein the robot arm is part of an arrangement comprising a track along the work table surface, wherein the robot arm is movably arranged on the track.

22. A method for additive fabrication of a three-dimensional (3D) object by means of an apparatus as claimed in any of the preceding claims.

23. The method according to claim 22, wherein the object is printed with vertical bed printing.

24. The method according to claim 22 or 23, wherein the at least one print head is depositing at least the first printing material layer having a width, length and a thickness, wherein the length of the first printing material layer is defined by means of a printing direction of the at least one print head, wherein a direction defined by the layer thickness extends substantially parallel to the horizontal, wherein substantially parallel includes an angle of 45-135 degrees with the horizontal, preferably between 65 - 115 degrees with the horizontal, more preferably between 80-100 degrees with the horizontal.

25. The method according to claim 22, 23 or 24, wherein the object is being printed mainly in a direction away from the inclined print surface.

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