WO2016172784A1

WO2016172784A1 - Improved stereolithography system

Info

Publication number: WO2016172784A1
Application number: PCT/CA2015/050860
Authority: WO
Inventors: Diego CASTANON
Original assignee: Fortier, Raymond
Priority date: 2015-04-30
Filing date: 2015-09-04
Publication date: 2016-11-03

Abstract

A stereolithography system comprises an emitting device and a tank disposed above the emitting device. The tank has an optically transparent bottom wall. There is a linear stage that extends away from the tank and a carrier platform is moveable along the linear stage away from the tank. There is also a wettable material at a bottom wall of the tank within the tank. The wettable material may be coated on the optically transparent bottom wall of the tank or the wettable material may overlay the optically transparent bottom wall of the tank.

Description

IMPROVED STEREOLITHOGRAPHY SYSTEM

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The present invention relates to a stereolithography system and, in particular, to a stereolithography system including a tank coated with a wettable material. Description of the Related Art

[0002] PCT Application Publication Number WO 2014/126837 to DiSimone et al, the full disclosure of which is incorporated herein by reference, discloses a method of forming a three-dimensional object. The method comprises providing a carrier and an optically transparent member having a build surface. The carrier and the build surface define a build region therebetween. The build region is filled with a polymerizable liquid and the build region is irradiated through the optically transparent member to form a solid polymer from the polymerizable liquid while concurrently advancing the carrier away from the build surface to form the three-dimensional object from the solid polymer, while also concurrently: (i) continuously maintaining a dead zone of polymerizable liquid in contact with the build surface, and (ii) continuously maintaining a gradient of polymerization zone between the dead zone and the solid polymer and in contact with each thereof, the gradient of polymerization zone comprising the polymerizable liquid in partially cured form. An apparatus for carrying out the method is also disclosed.

SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide an improved stereolithography system. [0004] There is accordingly provided a stereolithography system comprising an emitting device and a tank disposed above the emitting device. The tank has an optically transparent bottom wall. There is a linear stage that extends away from the tank and a carrier platform is moveable along the linear stage away from the tank. There is also a wettable material at the optically transparent bottom wall of the tank within the tank. The wettable material may be coated on the optically transparent bottom wall of the tank or the wettable material may overlay the optically transparent bottom wall of the tank. The tank may further include a reservoir in fluid communication with the wettable material. In other examples, the optically transparent bottom wall of the tank and the emitting device may be integral.

[0005] There is also provided a stereolithography system comprising a tank having an optically transparent bottom wall and emitting devices disposed along a peripheral edge of the optically transparent bottom wall of the tank. There is a linear stage that extends away from the tank and a carrier platform is moveable along the linear stage away from the tank. There is also a wettable material at the optically transparent bottom wall of the tank within the tank. The wettable material may be coated on the optically transparent bottom wall of the tank or the wettable material may overlay the optically transparent bottom wall of the tank. The tank may further include a reservoir in fluid communication with the wettable material. The optically transparent bottom wall of the tank may include a modified LCD monitor in which white back lights of the LCD monitor are replaced with UV LED lights which function as emitting devices.

BRIEF DESCRIPTIONS OF DRAWINGS

[0006] The invention will be more readily understood from the following description of the embodiments thereof given, by way of example only, with reference to the accompanying drawings, in which:

[0007] Figure 1 is a perspective view of an improved stereolithography system; [0008] Figure 2A is a perspective, sectional view of a resin tray of the stereolithography system of Figure 1 ;

[0009] Figure 2B is a perspective, sectional view of another resin tray of the stereolithography system of Figure 1 ; [0010] Figure 3 is a simplified schematic showing a gap between a wettable material on a bottom wall of the resin tray and a three-dimensional object being formed by the stereolithography system of Figure 1 ;

[0011] Figure 4 is an elevation view of the improved stereolithography system showing an object starting to be formed by the stereolithography system of Figure 1 ; [0012] Figure 5 is an elevation view of the improved stereolithography system showing an object being formed by the stereolithography system of Figure 1 ;

[0013] Figure 6 is an elevation view of the improved stereolithography system showing an object formed by the stereolithography system of Figure 1 ;

[0014] Figure 7 is a perspective view of another improved stereolithography system; and

[0015] Figure 8 is a perspective, sectional view of a resin tray of the stereolithography system of Figure 7.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

[0016] Referring to the drawings and first to Figure 1 , an improved stereolithography system 10 is shown. The stereolithography system 10 comprises a base 12 and a wall 14 that extends vertically from the base 12. There is a tank 16 mounted on the wall 14 and an emitting device 18 is mounted on the base 12. The tank 16 is mounted on the wall 14 above the emitting device 18. The emitting device may be any suitable light-emitting device which may be used to cure a polymerizable resin. There is a linear stage 20 that extends vertically away from the tank 16 and a carrier platform 22 is moveable along the linear stage 20. The stereolithography system 10, as thus far described, is a generally conventional stereolithography system used in a "top down" three-dimensional printing technique in which new cross-sections of an object being formed are formed at a bottom of the object being formed.

[0017] However, as best shown in Figure 2A, the tank 16 of the stereolithography system 10 has a novel structure. The tank 16 has a bottom wall 24 which is optically transparent and there is a plurality of side walls, for example, side walls 26, 28 and 30 which extend from the bottom wall 24 of the tank 16. There is a wettable material 32 at the bottom wall 24 of the tank 16 within the tank 16. The wettable material 32 may be coated on the bottom wall 24 of the tank 16 or the wettable material 32 may overlay the bottom wall 24 of the tank 16. The wettable material 32 may have a thickness of between 1 millimeter and 4 millimeters. In this example, the tank 16 also includes a reservoir 34 in fluid communication with the wettable material 32. There may be water in the reservoir 34 which may be applied to the wettable material 32 to keep the wettable material wet.

[0018] Figure 2B shows another tank 36 that may be used with the stereolithography system 10. The tank 36 has a bottom wall 38 which is formed from an optically transparent, wettable material, i.e. the bottom wall 38 of the tank is wettable. The tank also has a plurality of side walls, for example, side walls 40, 42, and 44 which extend from the bottom wall 38 of the tank 36. The tank 36 also includes a reservoir 46 in fluid communication with the bottom wall 38 of the tank 36. There may be water in the reservoir 46 which may be applied to the bottom wall 38 of the tank 36 to keep the bottom wall 38 of the tank 36 wet.

[0019] Referring now to Figure 3, and with reference back to Figure 2A, the wettable material 32 may be a hydrogel, e.g. silicone hydrogel, or any other suitable wettable material which results in a dead zone or a gap 48 at the interface between the wettable material 32 and resin in the tank 16. The gap 48 may be a result of intermolecular forces of repulsion between the wettable material 32 and the resin in the tank 16 and/ or the gap 48 may be the result of a layer of water which separates the wettable material 32 and the resin because the resin and water are immiscible. Figure 3 best shows a gap 48 between the wettable material 32 at the bottom wall 24 of the tank 16 (not shown in Figure 3) and an object 50 being formed from the resin in the tank. The gap 48 allows the object 50 to be formed continuously because the object 50 is not formed directly on the bottom wall 24 of the tank 16 thereby doing away with the need for the object 50 to be peeled or pulled away from the bottom wall 24 of the tank 16. It will be understood by a person skilled in the art that the resin is cured or polymerized by irradiation to form the object 50.

[0020] The wettable material 32 may be affixed to the bottom wall 24 of the tank 16 by using a mould to cast the wettable material 32 in liquid form over the bottom wall 24 of the tank 16 then curing the wettable material 32 to affix the wettable material 32 to the bottom wall 24 of the tank 16. Alternatively, an adhesive may be used to affix the wettable material 32 to the bottom wall 24 of the tank 16. Still alternatively, in other examples, the wettable material 32 may be affixed to the bottom wall 24 of the tank 16 by applying a vacuum to a hollow interior of the bottom wall 24 of the tank 16 through a conduit.

[0021] Figure 4 shows the object 50 starting to be formed using the stereolithography system 10. The carrier platform 22 is disposed within the tank 16 as the emitting device 18 emits a continuous blast of light 52 as the object 50 starts to be formed on the carrier platform 22. The carrier platform 22 then moves continuously and upwardly away from the tank 16 as the emitting device 18 emits the continuous blast of light 52 and the object 50 is formed continuously as shown in Figure 5. This process continues until the object 50 is fully formed as shown in Figure 6. The gap 48, shown in Figure 3, between the bottom wall 24 of the tank 16 and resin in the tank 16 allows the object 50 to be formed continuously because the object 50 is not formed directly on the bottom wall 24 of the tank 16, thereby doing away with the need for the object 50 to be peeled or pulled away from the bottom wall 24 of the tank 16.

[0022] A controller 54 may be used to control the duration and the intensity of the blast of light depending on the object being formed or part of the object being formed. The object 50 being formed in Figures 4 to 6 has solid parts, for example solid part 56, and hollow parts, for example hollow part 58. The controller 54 will increase the duration of the blast of light 52 and lower the intensity of the blast of light 52 during the formation of the solid part 56. Conversely, the controller 54 will decrease the duration of the blast of light 52 and increase the intensity of the blast of light 52 during the formation of the solid part 56. The duration of the blast of light 52 is increased during the formation of the solid part 56 because additional time is required for the resin to cure or polymerize due to the larger surface area being cured. The intensity of the blast of light 52 is lowered during the formation of the solid part 56 to minimize excess heat which may dry the wettable material 32. The duration of the blast of light 52 is decreased during the formation of the hollow part 58 because less time is required for the resin to cure or polymerize due to the smaller surface area being cured. However, the intensity of the blast of light 52 is increased during the formation of the hollow part 58 to accelerate the dimensional printing process.

[0023] Figure 7 shows another embodiment of an improved stereolithography system 60. The stereolithography system 60 comprises a base 62 and a wall 64 that extends vertically from the base 62. There is a tank 66 mounted on the wall 64. There is also a linear stage 68 that extends vertically away from the tank 66 and a carrier platform 70 is moveable along the linear stage 68. The stereolithography system 60 however does not have a light-emitting device mounted on the base 62 because the light-emitting device is integral with the tank 66.

[0024] The tank 66 is best shown in Figure 8 and has a bottom wall 72 which is optically transparent. There is a plurality of side walls, for example, side walls 74, 76 and 78 which extend from the bottom wall 72 of the tank 66. There is a wettable material 80 at the bottom wall 72 of the tank 66 within the tank 66. The wettable material 80 may be coated on the bottom wall 72 of the tank 66 or the wettable material 80 may overlay the bottom wall 72 of the tank 66. In this example, the tank 66 also includes a reservoir 82 in fluid communication with the wettable material 80. There may be water in the reservoir 82 which may be applied to the wettable material 80 to keep the wettable material wet.

[0025] The bottom wall 72 of the tank 66 further includes a plurality of light-emitting devices, for example, light-emitting devices 84 and 86, disposed along a peripheral edge thereof. The light-emitting devices provide a continuous blast to form an object. The bottom wall of the tank may be a modified LCD monitor in which white back lights of the LCD monitor are replaced with UV LED lights which function as light-emitting devices. This allows an image that would have previously been projected on the LCD monitor in white light to be continuous projected in a blast of UV light to form an object in the shape of the image. A controller 88, which is shown in Figure 7, controls the timing and intensity of the white light depending on the object being printed. [0026] It will be understood by a person skilled in the art that although the stereolithography systems as disclosed herein are used to continuously form an article that the stereolithography systems as disclosed herein may be used to form an article stepwise.

[0027] It will also be understood by a person skilled in the art that many of the details provided above are by way of example only, and are not intended to limit the scope of the invention which is to be determined with reference to the following claims.

Claims

What is claimed is:

1. A stereolithography system comprising: an emitting device; a tank disposed above the emitting device, the tank having an optically transparent bottom wall; a linear stage extending away from the tank and a carrier platform moveable along the linear stage away from the tank; and a wettable material at the optically transparent bottom wall of the tank within the tank.

2. The stereolithography system as claimed in claim 1 wherein the wettable material is coated on the optically transparent bottom wall of the tank.

3. The stereolithography system as claimed in claim 1 wherein the wettable material overlays the optically transparent bottom wall of the tank.

4. The stereolithography system as claimed in claim 1 wherein the tank further includes a reservoir in fluid communication with the wettable material.

5. A stereolithography system comprising: a tank having an optically transparent bottom wall; emitting devices disposed along a peripheral edge of the optically transparent bottom wall of the tank; a linear stage extending away from the tank and a carrier platform moveable along the linear stage away from the tank; and a wettable material at the optically transparent bottom wall of the tank within the tank.

6. The stereolithography system as claimed in claim 5 wherein the wettable material is coated on the optically transparent bottom wall of the tank.

7. The stereolithography system as claimed in claim 5 wherein the wettable material overlays the optically transparent bottom wall of the tank.

8. The stereolithography system as claimed in claim 5 wherein the tank further includes a reservoir in fluid communication with the wettable material.

9. The stereolithography system as claimed in claim 5 wherein the optically transparent bottom wall of the tank includes a modified LCD monitor in which white back lights of the LCD monitor are replaced with UV LED lights which function as emitting devices.

10. A stereolithography system comprising: an emitting device; a tank disposed above the emitting device, the tank having an optically transparent bottom wall formed from a wettable material; a linear stage extending away from the tank and a carrier platform moveable along the linear stage away from the tank.

11. The stereolithography system as claimed in claim 10 wherein the tank further includes a reservoir in fluid communication with the optically transparent bottom wall formed from a wettable material.