Plastic and nonmetallic article shaping or treating: processes – Stereolithographic shaping from liquid precursor
Reexamination Certificate
1999-02-08
2001-06-05
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Stereolithographic shaping from liquid precursor
C425S135000, C425S174400, C425S375000, C700S120000
Reexamination Certificate
active
06241934
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the formation of three-dimensional objects using a Rapid Prototyping and Manufacturing (RP&M) technique (e.g. stereolithography). The invention more particularly relates to the formation of three-dimensional objects using enhanced production control of prescribed stimulation and its application to a building material.
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 create 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 (3 DP). 3 DP is based on the selective solidification of layers of a powdered material which are solidified by the selective deposition of a binder thereon. 3 DP 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.
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. The material being dispensed may be solidified upon cooling, by heating, exposing to radiation, or upon application of a second physical material. A single material may be dispensed or multiple materials dispensed with each having different properties. 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 Menhenneft; 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, filed Sep. 27, 1996, and issued Aug. 24, 1999 by Earl et al. and U.S. application Ser. No. 08/722,335, filed Sep. 27, 1996, by Leyden et al., now abandoned (both assigned to 3D Systems, Inc. as is the instant application).
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.
Though, as noted above, the techniques of the instant invention are directed primarily to liquid-based stereolithography object formation, it is believed that some of the techniques may have application in the LOM and/or SDM technologies where application of a beam or other laminae forming element must be precisely controlled.
Needs exist in the stereolithographic arts for improved beam generation techniques and positioning techniques. A first need exists for enhanced effective life of solid state ultraviolet producing lasers in a stereolithographic system. A second need exists for maintaining substantially uniform exposure over the length of each vector while simultaneously scanning as fast as possible, maintaining adequate positional control and minimizing the overall exposure time. A third need exists for improved control of the laser power that is produced and applied to the building material in a stereolithographic system. A fourth need exists for improved efficiency in exposing the building material in a stereolithographic system when exposure is controlled by a plurality of different vector types. A fifth need exists for simplified techniques for determining the maximum useful laser power for exposing a given set of vectors.
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 stereolithography.
Mar 11, 1986
06/638,905
Aug 8, 1984
4,999,143
Hull, et al.
Discloses various removable support structures applicable to
Mar 12, 1991
stereolithography.
07/182,801
Apr 18, 1988
5,058,988
Spence
Discloses the application of beam profiling techniques useful
Oct 22, 1991
in stereolithography for determining cure depth and scanning
07/268,816
velocity, etc.
Nov 8, 1988
5,059,021
Spence, et al.
Di
Beers Ross D.
Everett Michael A.
3-D Systems, Inc.
D'Alessandro Ralph
Smalley Dennis R.
Tentoni Leo B.
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