Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-03-12
2003-09-30
Lorengo, Jerry A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S256000, C156S264000, C156S267000, C156S272200, C156S275700, C156S379800, C264S405000, C425S110000
Reexamination Certificate
active
06627030
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a variable lamination manufacturing (VLM) process and apparatus, and more particularly to a variable lamination manufacturing (VLM) process and apparatus, which is capable of fabricating a three-dimensional product by cutting strip-shaped material, such as foamed resin, thermoplastic resin, thermosetting resin, etc., into the unit shape part of variable width, inclinations and length using a four-degree-of-freedom linear heat cutting device, and stacking and bonding together the cut unit shape parts while the material is supplied in variable widths and thicknesses.
In addition, the present invention relates to a rapid prototyping method that is capable of obviating the need for post-processing and considerably reducing build time by improving the dimensional accuracy of the product in comparison with conventional rapid prototyping methods for fabricating trial products and molds.
2. Description of the Prior Art
A rapid prototyping method in accordance with the present invention can be utilized in various industrial uses, such as the fabrication of architectural models, trial products (of the turbine blades of aircrafts, of the impeller of centrifugal compressors, of cellular phones, or of the like), character products (such as Pikachu dolls, Dooly dolls, or the like), cores for lost foam casting, or the like. In particular, the rapid prototyping method can be utilized in the rapid production of parts each having three-dimensional shape that cannot be fabricated by a three or five-axial cutting process.
The conventional rapid prototyping methods may be classified into a method of hardening liquid material into a three-dimensional shape by the irradiation of laser beams and a method of bonding solid material in the form of particles or laminates into a product of a desired shape.
In the above description, the rapid prototyping method denotes a fabricating method of fabricating nonmetallic or metallic material, such as paper, wax, ABS or plastic, directly into a trial product or mold of a three-dimensional shape using three-dimensional computer aided design data. Recently, various materials such as metallic powder and metallic wire have been developed to be utilized as material for rapid prototyping methods.
In the meantime, stereolithography, one of the hardening methods, developed by 3D System Company is a method wherein a liquid photopolymer is selectively irradiated by laser beams to be solidified and one polymer layer is stacked on top of another.
As the stereolithography, there are known a method of partially irradiating laser beams commercialized by 3D System Co., Quadrax Co., Sony Co. and Dupont Co. and a method of irradiating a layer at a time using an ultraviolet lamp commercialized by Cubital Co. and Sculpting Co.
However, the stereolithography has a shortcoming in that solidified photopolymer contracts during hardening, thus being deformed. In addition, when a product having a protrusion is fabricated, there occurs a shortcoming that a support is needed to support photopolymer used to form the protrusion and prevents it from falling down. Furthermore, resin should be employed for the stereolithography, so that the strength of a product is reduced, thereby preventing the product from being functionally utilized.
As the method using powdered material, there are known selective laser sintering commercialized by DTM Co. and three dimension printing commercialized by Solingen Co., Z Corp., etc. and developed by MIT.
In the selective laser sintering, a product is fabricated in such a way that powdered plastic material is spread and the powder material is boned together by the irradiation of laser beams. The selective laser sintering is used to fabricate a metallic product and a mold using iron powder coated with plastic.
When a metallic product or mold is fabricated using iron powder coated with plastic, the plastic should be removed and the iron powder should be sintered to be combined together. In addition, there is required post-processing, such as copper infiltration, to fill in gaps between among iron powder. However, the selective laser sintering has a shortcoming in that dimensional accuracy cannot be achieved because the material is contracted during the post-processing.
In the three-dimensional printing, a liquid bonding agent is selectively added to spread powder to form a product. Using such three-dimensional printing, a ceramic shell for investment casting can be made of ceramic powder, or a product can be made of powder including starch as a chief ingredient. However, the three-dimensional printing has a shortcoming in that contraction occurs due to thermal deformation because post-processing is required to increase the density and strength of a product.
In the laminated object manufacturing commercialized by Helisys Co., a product is fabricated by repeating a process of bonding together multiple pieces of paper in the form of thin films and cutting bonded papers using a laser beams. However, though the laminated object manufacturing has an advantage in that the manufacturing cost of a product is low because paper is used as raw material, it has a defect in that labor is required to remove a finished product from surrounding excess material after the fabrication of the product.
For example, in a case where a spherical product is fabricated, when the spherical product is fabricated by stacking and cutting multiple pieces of paper, labor is required to remove the finished spherical product from the remaining paper portion because the spherical product is surrounded by the remaining paper portion. Though plastic thin plate has been developed and can be utilized in fabricating a plastic product, there occurs also the same shortcoming as that with paper.
In accordance with fused deposition modeling commercialized by Stratasys Co., a product is fabricated in such a way that plastic material in the form of filaments is passed between heated nozzles each having a shape similar to an extrusion die and is bonded together while being melted. However, such fused deposition modeling has a shortcoming in that the surface of the product is rough because material in the form of filaments is employed.
Hereinafter, a rapid prototyping method for a product of functional material such as metal or a mold is described.
In laser engineered net shaping developed by Santia National Lab and recently commercialized by Optomec Co., a product is fabricated in such a way that metallic substrate is partially heated to form a melted pool and metallic powder is dropped into the melted pool using gas.
However, the laser engineered net shaping has a shortcoming in that dimensional accuracy of a product is deteriorated due to deformation during solidification because a product is fabricated of melted metal. Additionally, the laser engineering net shaping has a shortcoming in that a product having a protrusion or cantilever cannot be fabricated because a product is fabricated of melted material.
Shape deposition manufacturing developed by Stanford Univ. and Carnegie Mellon Univ. is a technique in which a metallic deposition is combined with CNC machining. In the shape deposition manufacturing, metal is deposited and machined to have a desired thickness and a boundary shape using a CNC milling, the remaining portion in the same plane is filled with another metal, and the material is CNC-machined to form a layer. After the layer is completed, shot peening is performed to eliminate residual stress. A desired product is completed through the above-described series of processes.
However, the shape deposition manufacturing has a shortcoming in that a long time is required to fabricate a product because a plurality of processes are performed to complete a product.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a rapid prototyping method and apparatus in which material
Ahn Dong-Gyu
Lee Sang-Ho
Shin Bo-Sung
Yang Dong-Yol
Korea Advanced Institute of Science and Technology
Lorengo Jerry A.
Vidas, Arrett&Steinkraus PA
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