Plastic and nonmetallic article shaping or treating: processes – Stereolithographic shaping from liquid precursor
Reexamination Certificate
1999-02-08
2002-06-18
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Stereolithographic shaping from liquid precursor
C425S174400, C425S375000, C700S120000
Reexamination Certificate
active
06406658
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the formation of three-dimensional objects using a Rapid Prototyping and Manufacturing (RP&M) technique. The invention more particularly relates to the stereolithographic formation of three-dimensional objects using a plurality of different dimensioned beams of radiation.
BACKGROUND OF THE INVENTION
1. Related Art
Rapid Prototyping and Manufacturing (RP&M) is the name given to a field of technologies that can be used to form three-dimensional objects rapidly and automatically from three-dimensional computer data representing the objects. RP&M can be considered to include three classes of technologies: (1) Stereolithography, (2) Selective Deposition Modeling, and (3) Laminated Object Manufacturing.
The stereolithography class of technologies creates three-dimensional objects based on the successive formation of layers of a fluid-like material adjacent to previously formed layers of material and the selective solidification of those layers according to cross-sectional data representing successive slices of the three-dimensional object in order to form and adhere laminae (i.e. solidified layers). One specific stereolithography technology is known simply as stereolithography and uses a liquid material that is selectively solidified by exposing it to prescribed stimulation. The liquid material is typically a photopolymer and the prescribed stimulation is typically visible or ultraviolet electromagnetic radiation. The radiation is typically produced by a laser though other sources of radiation are possible such as arc lamps, resistive lamps, and the like. Exposure may occur by scanning a beam or by controlling a flood exposure by use of a light valve that selectively transmits or reflects the radiation. Liquid-based stereolithography is disclosed in various patents, applications, and publications of which a number are briefly described in the Related Applications section hereafter.
Another stereolithography technology is known as Selective Laser Sintering (SLS). SLS is based on the selective solidification of layers of a powdered material by exposing the layers to infrared electromagnetic radiation to sinter or fuse the powder particles. SLS is described in U.S. Pat. No. 4,863,538, issued Sep. 5, 1989, to Deckard. A third technology is known as Three Dimensional Printing (3DP). 3DP is based on the selective solidification of layers of a powdered material which are solidified by the selective deposition of a binder thereon. 3DP is described in U.S. Pat. No. 5,204,055, issued Apr. 20, 1993, to Sachs.
The present invention is primarily directed to stereolithography using liquid-based building materials (i.e. medium). It is believed, however, that the techniques of the present invention may have application in the other stereolithography technologies in order to achieve faster object formation times and/or higher object resolution.
Selective Deposition Modeling, SDM, involves the build-up of three-dimensional objects by selectively depositing solidifiable material on a lamina-by-lamina basis according to cross-sectional data representing slices of the three-dimensional object. One such technique is called Fused Deposition Modeling, FDM, and involves the extrusion of streams of heated, flowable material which solidify as they are dispensed onto the previously formed laminae of the object. FDM is described in U.S. Pat. No. 5,121,329, issued Jun. 9, 1992, to Crump. Another technique is called Ballistic Particle Manufacturing, BPM, which uses a 5-axis, ink-jet dispenser to direct particles of a material onto previously solidified layers of the object. BPM is described in PCT publication numbers WO 96-12607, published May 2, 1996, by Brown; WO 96-12608, published May 2, 1996, by Brown; WO 96-12609, published May 2, 1996, by Menhennett; and WO 96-12610, published May 2, 1996, by Menhennett. A third technique is called Multijet Modeling, MJM, and involves the selective deposition of droplets of material from multiple ink jet orifices to speed the building process. MJM is described in U.S. Pat. No. 5,943,235 issued Aug. 24, 1999 to Earl et al. and U.S. patent application Ser. No. 08/722,335, filed Sep. 27, 1996, by Leyden et al., now abandoned.
Though, as noted above, the techniques of the instant invention are directed primarily to liquid-based stereolithography object formation, it is believed that the techniques may have application in the SDM technologies to enhance object resolution and/or to decrease object formation times.
Laminated Object Manufacturing, LOM, techniques involve the formation of three-dimensional objects by the stacking, adhering, and selective cutting of sheets of material, in a selected order, according to the cross-sectional data representing the three-dimensional object to be formed. LOM is described in U.S. Pat. No. 4,752,352, issued Jun. 21, 1988, to Feygin, U.S. Pat. No. 5,015,312, issued May 14, 1991, to Kinzie, and U.S. Pat. No. 5,192,559, issued Mar. 9, 1993, to Hull et al.; and in PCT Publication No. WO 95-18009, published Jul. 6, 1995, by Morita.
It is believed that the techniques of the present invention may have application in the LOM technologies to enhance object resolution when using a laser beam or mechanical cutting tool to cutout cross-sections and dissecting or sublimating the non-cross-section regions.
Various techniques for enhancing object formation speed have been described previously. In particular various techniques have been described in U.S. Pat. No. 5,089,185, issued Feb. 18, 1992 to Hirano. This patent describes the use of a large diameter light flux for a section having a thickness larger than the diameter of the light flux and using a small diameter light flux for sections having a thickness smaller than the diameter of the light flux having the large diameter. This patent indicates, inter alia, that the light flux having the small diameter is connected to a low power laser source while the light flux having the large diameter is connected to a high power laser source.
Though this patent teaches the desire to use a large diameter light flux and a small diameter light flux, it fails to provide any teachings concerning how to manipulate object data to distinguish regions requiring the small diameter light flux and those capable of being formed using the large diameter light flux. This reference further fails to teach the desirability of distinguishing cross-sectional regions from one another when determining where to apply the large diameter and small diameter light fluxes.
A need remains in the art for techniques that allow automatic, effective, and reliable utilization of multiple beams having different diameters.
2. Other Related Patents and Applications
The patents, applications, and publications mentioned above and hereafter are all incorporated by reference herein as if set forth in full. Table 1 provides a listing of patents and applications co-owned by the assignee of the instant application. A brief description of subject matter found in each patent and application is included in the table to aid the reader in finding specific types of teachings. It is not intended that the incorporation of subject matter be limited to those topics specifically indicated, but instead the incorporation is to include all subject matter found in these applications and patents. The teachings in these incorporated references can be combined with the teachings of the instant application in many ways. For example, the references directed to various data manipulation techniques may be combined with the teachings herein to derive even more useful, modified object data that can be used to more accurately and/or efficiently form objects. As another example, the various apparatus configurations disclosed in these references may be used in conjunction with the novel features of the instant invention.
TABLE 1
Related Patents and Applications
Patent No.
Issue Date
Application
No.
Filing Date
Inventor
Subject
4,575,330
Hull
Discloses fundamental elements of
Mar 11, 1986
stereolithography.
06/638,905
Aug 8, 1984
4,99
Everett Michael A.
Guertin Michelle D.
Manners Chris R.
Nguyen Hop D.
Partanen Jouni P.
3-D Systems, Inc.
D'Alessandro Ralph
Tentoni Leo B.
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