Patent Application
20160046071
The technical field generally relates to an apparatus for peeling in the production of three-dimensional, and particularly to an apparatus for assisting the peeling step in three-dimensional printing through stereolithography.
Three-dimensional printing (3D printing) uses an additive process to lay down successive layers of material under computer control to create an object of almost any shape or geometry. in recent years, the rapid development and maturity of 3D printing has attracted various applications, ranging from manufacturing to medical fields.
Various additive processes have been developed over the past decades. The main differences between processes are in the way layers are deposited to create parts and in the materials that are used For example, with laminated object manufacturing (LOM), thin layers of material, such as paper, polymer, metal, and so on, are cut to shape and joined together. Other methods melt or soften material to produce the layers, such as selective laser melting (SLM) or direct metal laser melting (MILS), selective metal sintering (SLS), fused deposition modeling (FDM), or fused filament fabrication (FFF). A different approach is to cure liquid materials using different sophisticated technologies, such as stereolithography (STA).
Stereolithography was patented by Hull in 1986 as a method and apparatus for making solid objects by successively “printing” thin layers of an ultraviolet curable material, one on top of the other. The patent described a concentrated beam of ultraviolet light focused onto the surface of a tank filled with liquid photopolymer. The light beam draws the object onto the surface of the liquid layer by layer, using polymerization or cross-linking to create a solid, a complex process which requires automation. Based on the incoming direction of the light, the stereolithography can be categorized as a top-down type or bottom-up type. Bottom-up stereolithography usually includes a series of exposure steps and separation phases, wherein the exposure step is to solidify the photopolymer and the separation step is to raise the solidified photopolymer layer to separate it from the tank bottom. The separation step is also referred to as peeling by the industry.
However, a major issue often encountered in the actual application of stereolithography is the peeling/separation process, wherein a newly solidified layer of the polymer attached to the previously solidified layers is separated from the tank bottom to create a smooth layer surface without breaking the newly solidified layer from the previous layers. Different solutions are proposed to address the adherence of the newly solidified layer to the tank bottom during the separation step of the current stereolithography process. For instance, a flexible, elastic separating layer made of non-stick material is used at the bottom of a tank containing the liquid polymer to ease the peeling of the newly solidified layer from the liquid polymer in the tank. Another proposed technique is, after a polymer layer has solidified and adhered to the bottom of the tank, the bottom of the tank is peeled from the polymer layer adjacent to an anchored portion of the tank and partially moves upwards to create an ease of separation.
As the separation of the newly solidified layer from the tank bottom remains a critical factor in the performance of stereolithography, it is desirable to devise an effective solution to ensure the smooth execution of the peeling step.
An exemplary embodiment describes an apparatus for peeling in the production of three-dimensional (3D) objects with a long-lasting layer separation material. The apparatus for peeling in the production of three-dimensional objects is applicable to a 3D printer having a build platform assembly, further including a build platform to attach to a three-dimensional object to be produced, a build arm to hold the build platform, one or more support guides to support the build arm and an actuator to move the build arm holding the build platform along the z-axis linearly; a tank to hold a liquid photopolymer, the tank having a transparent or translucent bottom separation layer to allow light from a light source to pass through the transparent bottom separation layer of the tank to solidify the liquid photopolymer; and a main support frame to attached to the tank to support the tank. The apparatus for peeling in the production of three-dimensional objects is disposed underneath the transparent bottom separation layer of the tank, including a transparent top plate to support the transparent bottom separation layer of the tank when in an ‘up’ position; a lower support frame, disposed underneath the transparent top plate to support the transparent top plate; a tilt plate, connected by a pivot connector to the main support frame of the 3D printer; and a tilt actuator, disposed opposite to the pivot connector underneath the tilt plate to move the tilt plate along with the transparent top plate and the lower support frame downwards to a ‘down’ position to separate the transparent top plate from the transparent bottom separation layer of the tank.
The foregoing will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings.
The embodiments can be understood in more detail by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawings, wherein:
In the following detailed description, for the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
Refer to Both
As aforementioned, one end of the tilt plate 24 is connected by a pivot connector 27 to the main frame 25 of the 3D printer. The pivot connector 27 may be realized with a hinge, as shown in
The tilt actuator 31 provides the force to move the tilt plate 24 upwards or downwards. It should be noted that the tilt actuator 31 may apply the force directly to the tilt plate 24 or through the use of a spring or other similar elements to exert the force to move the tilt plate 24.
It is also worth noting that the actuator 10 to move the build arm 12 along the z-axis linearly can be realized by, but not restricted to, a motor. Similarly, the tilt actuator 31 to tilt the tilt plate 24 downwards can also be realized by, but not restricted to, a motor. The tank 16 may be fixed to the main support frame 25 for further stability. In addition, the transparent bottom separation layer is made of a low surface energy material. Low surface energy materials are desired due to their non-stick properties. Examples of transparent or translucent low surface energy materials include, but are not limited to the fluoropolymers FEP, PTFE, PFA, MFA, and so on.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
The present application is based on, and claims priority from, U.S. Provisional Application No. 62/038,371, filed Aug. 18, 2014, the disclosure of which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62038371 | Aug 2014 | US |
