Powder deposition head for 3D printing

Abstract

A powder deposition head for three-dimensional printing, comprising a powder reservoir (1) in a platform (2), an ultrasonic transducer (3) connected to the platform (2), for producing high-frequency vibrations, a nozzle (4) connected to the powder reservoir (1), the nozzle (4) comprising two plates (5) forming a funnel, said funnel ending with a slit (6) having an adjustable width, wherein the powder deposition head further comprises limiting means (7) configured to adjust length of the slit (6).

Description

[0001] Powder deposition head for 3D printing

[0002] Background

[0003] The invention relates to three-dimensional (3D) printing, also known as additive manufacturing, and especially to a powder deposition head of 3D printing.

[0004] Powder based additive manufacturing processes use various methods of powder deposition, some of which include hoppers with ultrasonic transducers. Ultrasonic transducers generate high-frequency vibrations that are applied to powders. The ultrasonic energy helps to fluidize the powder so a desired quantity to achieve a layer of a certain height can be applied on a printing plate, which can be used to create three dimensional structures. The ultrasonic wave can be of different kinds such as square wave, triangle wave, and sin wave.

[0005] There are several conventional solutions, such as in powder bed fusion and binder jetting processes, which are slow with low resolution, so the finished quality is lacking. Some solutions are fast and expensive but has a pixelated deposition which adds to roughness. This is especially undesirable for cooling and fluid flow related applications. Some solutions support only few materials in a single print.

[0006] Brief disclosure

[0007] An object of the invention is thus to provide an arrangement that solves or at least alleviates the aforementioned challenges. The invention is based on providing a powder deposition head with limiting means configured to adjust length of a slit of the nozzle.

[0008] Brief description of the drawings

[0009] The invention will now be described in more detail in connection with preferred embodiments and with reference to the accompanying drawings, in which:

[0010] Figure 1 illustrates a diagonal top view of a powder deposition head according to an embodiment;

[0011] Figure 2 illustrates a longitudinal side view of the embodiment of Figure 1;

[0012] Figure 3 illustrates a transversal side view of the embodiment of Figure 1;

[0013] Figure 4 illustrates a bottom view of the embodiment of Figure 1 when the limiting means are in one position; Figure 5 illustrates a bottom view of the embodiment of Figure 1 when the limiting means are in another position;

[0014] Figure 6 illustrates a transversal cross-sectional view of the embodiment of Figure 1;

[0015] Figure 7 illustrates a closer cross-sectional view of a ridge;

[0016] Figure 8 illustrates a longitudinal cross-sectional view of the embodiment of Figure 1;

[0017] Figure 9 illustrates a diagonal top view of a partial powder deposition head according to another embodiment;

[0018] Figure 10 illustrates a transversal cross-sectional view of the embodiment of Figure 9;

[0019] Figure 11 illustrates a closer view of the cross-section of Figure 10. Detailed description of embodiments

[0020] Figure 1 illustrates a diagonal top view of a powder deposition head according to an embodiment. Figure 2 illustrates a longitudinal side view and Figure 3 illustrates a transversal side view of the embodiment of Figure 1. Figure 4 illustrates a bottom view when limiting means 7 are in one position. Figure 5 illustrates a bottom view of the embodiment when the limiting means 7 are in another position. Figure 6 illustrates a transversal cross-sectional view of the embodiment of Figure 1. Figure 7 illustrates a closer cross-sectional view of a ridge. Figure 8 illustrates a longitudinal cross-sectional view of the embodiment of Figure 1.

[0021] The present invention pertains to a powder deposition head for three-dimensional printing, wherein the powder deposition head comprises a powder reservoir 1 in a platform 2, which is connected to the platform 2, and an ultrasonic transducer 3 for producing high-frequency vibrations. A nozzle 4 is connected to the powder reservoir 1.

[0022] The powder reservoir 1 can be a closed-top or an open-top stationary powder reservoir 1. In some 3D printers, each powder layer is formed by transferring a predetermined quantity of build powder from the powder reservoir 1 and then pushing that quantity of powder via the nozzle 4 on top of a powder bed (not shown) to form a powder layer. The powder reservoir 1 may have an oval shaped opening on top with a similar oval shaped interior, however, the opening can have other shapes. In the accompanying Figures, the powder reservoir 1 comprises two longitudinal walls 24 and two transverse walls 25. The longitudinal walls 24 can be made of straight sections, and the transverse walls 25 made of at least partially curved sections, forming the oval shaped interior. However, in some embodiments, the longitudinal walls 24 and the transverse walls 25 may have different sections from the Figures.

[0023] The platform 2 in this context can refer to a horizontal base which supports the powder reservoir 1 to stay upright and unmoving. The longitudinal wall 24 and / or the transverse wall 25 of the powder reservoir 1 and the platform 2 may form an L-shaped structure and they may be integrated as one solid part.

[0024] Ultrasonic transducer 3 is for generating ultrasound. It can use piezoelectric transducer or capacitive transducer. In the accompanying Figures, two ultrasonic transducers 3 are shown, one on opposite side of the powder reservoir 1, and above it without contacting the powder reservoir 1. However, the number and the location of the ultrasonic transducers 3 may vary depending on the size and design of the powder deposition head. They may be alternatively located on lateral sides of the powder reservoir 1, for example directly contacting the longitudinal wall 24 of the powder reservoir 1.

[0025] The powder deposition head may further comprise a vertical guide (not shown) configured to keep the powder deposition head vertically linear during the ultrasonic vibration. The vertical guide may comprise a linear bearing flange.

[0026] The powder deposition head may further comprise a saddle clip 19 for anchoring the ultrasonic transducer 3 to any component moving the powder deposition head. This can rotate or translate the powder deposition head. Inside the powder reservoir 1 may locate one or more vibration motors 20 for vibrating the powder for a better powder separation. Each ultrasonic transducer 3 may be connected to a transducer connection bracket 21 which can be a C-bracket which may partially enclose an actuator 13.

[0027] The nozzle 4 comprises two longitudinal plates 5 forming a funnel and ending with a slit 6 having an adjustable width. The nozzle 4 and the powder reservoir 1 are connected in such a way that the build powder can be moved, either assisted or due to gravity, from the powder reservoir 1 to the nozzle 4 without obstruction. The longitudinal plates 5 and the longitudinal walls 24 may be directly joined. The nozzle 4 may also share the same platform 2 with the powder reservoir 1. The platform 2 can be made of more than one horizontal base, which are rigidly joined together. As shown in Figure 8, the nozzle 4 may have end walls 26 perpendicular to the longitudinal plates 5, which are also forming a funnel. The end walls 26 and the transverse walls 25 may be directly joined. The end walls 26 may be curved so that there are no sharp edges on inner surfaces. The powder deposition head further comprises limiting means 7 configured to adjust the length of the slit 6. The width of the slit 6 is typically adjusted manually depending on the powder composition. Some powder has larger average grain size which require wider slit 6, while some powder has smaller average grain size which require narrower slit 6. For example, the width of the slit 6 may be adjustable with shims 15 or a manual slide, which may be located at the longitudinal ends of the nozzle 4. However, in traditional powder deposition heads, the length of the slit 6 is not adjustable.

[0028] The limiting means 7 may comprise a slider 8 movable back-and-forth and configured to cover or restrict an end of the slit 6. The movement can be longitudinal movement parallel to a longitudinal axis of the powder deposition head. By covering or restricting the end of the slit 6, the initial length of the slit 6 is shortened to a preferred range which is adjusted depending on the 3D design. The slider 8 may directly touch the plates 5 so that there is no gap between the slider 8 and the nozzle 4. Alternatively, the gap may be so small that no powder particles can pass through it.

[0029] The limiting means 7 may further comprise a slider holder 9 for holding a longitudinal edge of the slider 8. The slider holder 9 and the slider 8 may be attached to each other by welding or manufactured from one piece by casting, for example. The slider 8 may be a lightweight and thin sheet, made of metal for example, which is easily movable via an actuator 13. The slider 8 may comprise a horizontal section 8a, for example in the form of a planar sheet. In this context, the term “horizontal” may refer to a substantially horizontal line, or where the horizontal section can be at 80-100 degrees in relation to the line of gravity. The horizontal section 8a may have a uniform width and a constant height. However, in some embodiments the horizontal section 8a may have variable width and / or height.

[0030] In the accompanying Figures 1-8, the limiting means 7 is located beneath the two plates 1 and beneath the platform 2. The slider 8 is illustrated as a bent sheet having a horizontal section 8a in the middle and two inclined side sections 8b, forming a plate-like cross-section. The slider holder 9 is arranged to hold at least partially the inclined side section 8b. There may be one slider holder 9 holding each inclined side section 8b. The slider holder 9 can be any shape of component suitable for holding and rigidly supporting the slider 8. In the accompanying Figures 1-8, the slider holder 9 is a profile having a L-shape cross-section. However, other shape of profiles may be implemented. Figure 7 illustrates a closer cross-sectional view of a ridge 18 which may be implemented in some embodiments. The slider 8 may further comprise the ridge 18 protruding from an upper surface of the horizontal section 8a, wherein the ridge 18 is at least partially arranged within the slit 6. The ridge 18 may have a uniform width and a constant height. However, in some embodiments the ridge 18 may have a variable width and / or height. The ridge 18 can have a same length as the slider 8 which may facilitate its manufacturing. However, the ridge 18 may have a shorter length so that it does not completely reach one end of the slider 8. The ridge 18 is arranged to fit within the slit 6 and between the plates 2 so that it at least partially interlocks with the plates 2. The width of the ridge 18 may be slightly smaller than the width of the slit 6 so that the ridge 18 can move within the slit 6 without additional friction when the limiting means 7 is moved. The space between the plate 2 and the ridge 18 may be so small that the powder particles cannot pass through. The ridge 18 may not reach inside the nozzle 4 so the height of the ridge may not exceed the thickness of the plates 5.

[0031] The limiting means 7 may be movable via at least one guide rail 10 arranged horizontally below the platform 2. The guide rail 10 may be fixed to the underside of the platform 2. The slider holder 9 may be connected to the guide rail 10 via a linear bearing 11, for example within a carriage. The linear bearing 11 and the slider holder 9 may be rigidly attached to each other, for example using fasteners or welding or adhesive. The linear bearing 11 may be arranged between the guide rail 10 and the slider holder 9 so that the slider holder 9 moves together with the linear bearing 11 in relation to the guide rail 10.

[0032] The guide rail 10 can be a standard linear motion rail, for example, having wider top and bottom ends, wherein the top end is contacting the underside of the platform 2 and to bottom end is contacting the linear bearing 11. The limiting means 7 may be movable via two guide rails 10 arranged horizontally on both sides of the slit 6. Both guide rails 10 may be arranged at an equal distance away from the slit 6.

[0033] The limiting means 7 may comprise two sliders 8, arranged on both ends of the slit 6 so that one slider 8 covers or restricts one end of the slit 6 and another slider 8 covers or restricts the opposite end of the slit 6. Both sliders 8 may be moveable together in relation to each other. The sliders 8 may be configured to move equally but in opposite or in same direction, or they can be separately configured to move unequally in the opposite or in the same direction. Moving equally in the opposite directions may be most effective way to implement the invention. As illustrated in Figure 4, the sliders 8 may be moved to completely cover the slit 6.

[0034] The limiting means 7 may comprise two sliders 8 which are movable via the same at least one guide rail 10. In the embodiment illustrated in Figures 1-8, the two sliders 8 are movable via the same two guide rails 10. One guide rail 10 may reach from one end of the powder deposition head to the opposite end. Alternatively, there may be two shorter guide rails 10 instead of one long guide rail 10.

[0035] The limiting means 7 may comprise an actuator 13, which can be a piezoelectric motor, a linear stepper motor, or a linear servo motor configured to actuate the limiting means 7 by moving the slider 8. For example, the linear stepper motor may use a ball screw 14, a ball screw support 16 and a ball nut 17 to cause the slider 8 to move. The actuator 13 may be attached to the platform 2 using an actuator mount 22 which supports the actuator 13 and keeps it fixed to the platform 2. The limiting means 7 may comprise two linear stepper motors.

[0036] One slider 8 may be actuated by one actuator 13 so the embodiment of Figure 1 comprises two actuators 13. However, in some embodiments, one actuator 13 may actuate both sliders 8. In the Figure 1, the actuators 13 are located on both sides of the powder reservoir 1 and mounted on the platform 2. However, they can be located at other places depending on the powder deposition head design, for example next to the platform 2 or at a distance away from the platform 2.

[0037] The limiting means 7 may further comprise a slider connector arm 12 arranged over the platform 2 for supporting the slider 8 or the slider holder 9. The slider connector arm 12 ensures that both sliders 8 can move together. The slider connector arm 12 can be in the shape of an arc so that one end of the arc is directly connected to one slider holder 9 piece and another end of the arc is directly connected to the second slider holder 9 piece. The arc may span over the platform 2 and the powder reservoir 1. The slider connector arm 12 may be connected to the actuator 13 via a ball screw, for example. There may be two or more slider connector arms 12 in the powder deposition head, for example each slider 8 is supported by its own slider connector arm 12. The slider connector arm 12 may be located between the ultrasonic transducers 3, but depending on the overall design of the powder deposition head, the location may vary.

[0038] Figure 9 illustrates a diagonal top view of a partial powder deposition head according to another embodiment. Figure 10 illustrates a transversal cross-sectional view of the embodiment of Figure 9. Figure 11 illustrates a closer view of circled area of the cross-section of Figure 10. The rest of the features illustrated in Figure 1 is very similar to the one explained in connection with Figures 1-8. Therefore, the embodiment of Figures 9-11 is in the following mainly explained by pointing out differences.

[0039] In this embodiment, the limiting means 7 is at least partially located between the two plates 5 inside the nozzle 4. The limiting means 7 may also be at least partially located inside the powder reservoir 1 so that the slider 8 may divide the nozzle 4 into two halves, particularly to two longitudinal halves.

[0040] The slider 8 may comprise a vertical section 8c, wherein a first longitudinal edge of the vertical section 8c is arranged to at least partially block the slit 6. In this context, the term “vertical” may refer to a substantially vertical line, or where the vertical line can be at a maximum angle of 10 degrees in relation to the line of gravity. The vertical section 8c may also be at least partially provided within the slit 6 by interlocking with the plates 5. The vertical section 8c may have a uniform width and a constant height. However, in some embodiments the vertical section 8c may have variable width and / or height. The width of the vertical section 8c may be slightly smaller than the width of the slit 6 so that the slider 8 can move within the slit 6 without additional friction when the limiting means 7 is moved. The space between the plate 2 and the vertical section 8c may be so small that the powder particles cannot pass through.

[0041] The slider holder 9 may be a horizontal rod arranged on a second longitudinal edge of the slider 8. The slider holder 9 may be located above the nozzle 4 or within the nozzle 4. The horizontal rod can be any type of straight bar having a constant cross-section, such as a circle, oval or polygonal. The slider holder 9 and the slider 8 may be attached to each other by welding or manufactured from one piece by casting, for example. However, in some embodiments the slider holder 9 can have same width as the slider 8 and the combination of the slider 8 and the slider holder 9 is arranged as one vertical section 8c.

[0042] The slider 8 and the slider holder 9 may be arranged to move together through an aperture 23 on the transverse wall 25 of the powder reservoir 1. Alternatively, the aperture 23 may also be arranged on the end walls 26 of the nozzle 4. The aperture 23 may have a same or slightly larger cross section as the slider holder 9 and the slider 8 so that the friction is decreased but the powder particles cannot pass through the aperture 23. The limiting means 7 may comprise two sliders 8 and slide holders 9 so the aperture 23 may merge with the slit 6 as one long opening extending from one transverse wall 25 to another. One end of the slider holder 9 may be connected to a similar aforementioned actuator 13, wherein said end is located outside the powder reservoir 1. The limiting means 7 may comprise two sliders 8 moveable together in relation to each other.

[0043] With the present invention, the length of the slit 6 of the powder deposition head is completely adjustable according to the desired pattern of the 3D design. The actuator 13 may be connected to a processing unit, for example a computer or other data processing device, which may be configured to process the information of the stored 3D file and produce outputs to move the powder deposition head and control the actuator 13 to move the slider 8 to produce the 3D geometry according to the file.

[0044] One 3D printer may comprise at least one powder deposition head as described above. However, several powder deposition heads side by side for different material may also be assembled in one 3D printer.

[0045] Reference numbers

[0046] 1 powder reservoir

[0047] 2 platform

[0048] 3 ultrasonic transducer

[0049] 4 nozzle

[0050] 5 plate

[0051] 6 slit

[0052] 7 limiting means

[0053] 8 slider

[0054] 8a horizontal section

[0055] 8b side section

[0056] 8c vertical section

[0057] 9 slider holder

[0058] 10 guide rail

[0059] 11 linear bearing

[0060] 12 slider connector arm

[0061] 13 actuator

[0062] 14 ball screw

[0063] 15 shims 16 ball screw support

[0064] 17 ball nut

[0065] 18 ridge

[0066] 19 saddle clip

[0067] 20 vibration motor

[0068] 21 transducer connection bracket 22 actuator mount

[0069] 23 aperture

[0070] 24 longitudinal wall

[0071] 25 transverse wall

[0072] 26 end wall

Claims

Claims1. A powder deposition head for three-dimensional printing, comprisinga powder reservoir in a platform,an ultrasonic transducer connected to the platform, for producing high-frequency vibrations,a nozzle connected to the powder reservoir, the nozzle comprising two plates forming a funnel, said funnel ending with a slit having an adjustable width, andlimiting means configured to adjust length of the slit.

2. The powder deposition head according to claim 1, wherein the limiting means comprises a slider movable back-and-forth and configured to cover or restrict an end of the slit.

3. The powder deposition head according to claim 2, wherein the limiting means further comprises a slider holder for holding a longitudinal edge of the slider.

4. The powder deposition head according to claim 2 or 3, wherein the limiting means comprises two sliders, arranged at both ends of the slit, which are moveable together in relation to each other.

5. The powder deposition head according to any one of claims 2-4, wherein the slider comprises a horizontal section.

6. The powder deposition head according to claim 5, wherein the slider comprises a ridge protruding from the horizontal section, wherein the ridge is at least partially arranged within the slit.

7. The powder deposition head according to any one of claims 2-6, wherein the slider is located beneath the two plates.

8. The powder deposition head according to claim 7, wherein the slider is movable via a at least one guide rail arranged horizontally below the platform.

9. The powder deposition head according to claim 8, wherein the slider is movable via two guide rails arranged horizontally on both sides of the slit.

10. The powder deposition head according to claim 8 or 9, wherein the limiting means comprises two sliders which are movable via the same at least one guide rail.

11. The powder deposition head according to any one of claims 8-10, wherein the limiting means comprises a linear bearing arranged between the guide rail and the slider holder.

12. The powder deposition head according to any one of claims 2-11, wherein the limiting means further comprises a slider connector arm over the platform for supporting the slider or the slider holder.

13. The powder deposition head according to any one of claims 2-4, wherein the slider is at least partially located between the two plates inside the nozzle.

14. The powder deposition head according to claim 2, wherein the slider comprises a vertical section, wherein a first longitudinal edge of the vertical section is arranged to at least partially block the slit.

15. The powder deposition head according to claim 3, wherein the slider holder is a horizontal rod arranged on a second longitudinal edge of the slider.

16. The powder deposition head according to claim 15, wherein the slider and the horizontal rod are arranged to move together through an aperture on a transverse wall of the powder reservoir.

17. The powder deposition head according to any one of claims 1-16, wherein the width of the slit is adjustable with shims or a manual slide.

18. The powder deposition head according to any one of claims 1-17, wherein the powder deposition head further comprises a vibration motor.

19. The powder deposition head according to any one of claims 1-18, wherein the limiting means comprises an actuator, which is a piezoelectric motor, a linear stepper motor, or a linear servo motor configured to actuate the limiting means by moving the slider.

20. A 3D printer, comprising the powder deposition head according to any one of claims 1-19.

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