当前申请(专利权)人：
DE ANGELIS, ALFREDO
原始申请(专利权)人：
DE ANGELIS, ALFREDE
当前申请(专利权)人地址：
65 India Row, Apartment 39E, Boston, MA, US
代理机构：
ALLSOP, JOHN ROWLAND
摘要：
A method of automated layer-wise fabrication of a three-dimensional part from a computer model through controlled deposition and extraction of materials. The method integrates the precision control of established subtractive processes with additive processes optimised to produce desired material properties in order to produce a superior rapid prototyping system that does not suffer from the short-comings of prior art systems.
技术问题语段：
Conventional part production methods are neither time nor cost effective when only a small number of units are needed because they require expensive part-specific tooling, setting up machining protocols, and generating and programming three-dimensional (3-D) tool paths which require much time and professional expertise.|The cost and time to set up and run machine-specific tooling, along with the initial capital costs for tooling, make conventional prototyping/small production run processes both time and cost intensive.|Furthermore, conventional prototyping methods are limited in practice to simple part geometries.|Complex parts involving inner features and cores/cavities are difficult to produce using conventional techniques and often require precision casting methods which are highly expensive, time consuming, and require a broad range of expertise.|Automated prototyping machines, furthermore, require a minimum of human expertise for successful operation and a relatively negligible amount of set up time for a particular part.|The precision is only limited by the boundary of photopolymerization initially, but as the parts continue curing in the post build stage, warpage becomes a limiting factor.|The material properties of the parts are also limited by the material properties of photopolymers.|While this process creates complicated geometries, the sintered material densities are low.|Consequently, the mechanical properties of SLS parts are relatively unsuitable for functional prototypes.|Increasing the density of SLS parts would require a higher degree of sintering/melting of the part powder, thereby compromising the geometric control provided by SLS.|Obtaining stress-free layers with desitable material properties involves significant tradeoffs with geometric control of the part.|The building of prototypes from welded or adhered precut laminations as in the Laminations Method, moreover, suffers from a tradeoff between inter-lamination bonding and geometric control, as well as from several precision handling problems associated with complicated part cross sections.|These systems, however, have the disadvantage of porosity (low density) and poor bonding in green parts (prior to oven baking) due to the fluid mechanics and physics of the printing and binding processes.|Once the parts are oven heated to bake out the binder material, warpage and distortion related to shrinkage limit the attainable precision of the final parts.|All of the present rapid prototyping methods, therefore, unfortunately are subject to contain inherent difficulties and limitations in aspects of their prototype creation.|In summary, the key disadvantages associated with one or more of the current systems are: (1) poor material properties and/or distribution of material properties; (2) poor geometric control and/or difficulty with complex geometry; and (3) trade off between geometric part control and interlayer bond strength and/or part properties, such as density or microstructure.|Furthermore, the additive technologies which distinguish these processes all involve a tradeoff between maintaining a high degree of geometric precision and attaining suitable material properties in the final part.
技术功效语段：
[0017]An object of the present invention, therefore, is to provide an improved method of automated manufacturing of prototypes and/or small quantities of items that, unlike prior art techniques based upon incrementally adding material to build up the item, with attendant requirements of a high degree of precision, uses the established and precise methods of subtractive processes in conjunction with additive processes optimized to attain specified material properties, to provide improved rapid prototyping that obviates shortcomings of such prior art techniques.SUMMARY OF INVENTION
权利要求：
1. A method of automated layerwise fabrication of a three-dimensional part through controlled deposition and extraction of materials, that comprises, of generating sequences of part and complementary support material(s) contours corresponding to each layer (L), depositing material(s) for one or more of said contours onto a work surface within a processing enclosure (14), material(s) processing (5, 6) said deposited contour(s) in order to achieve prespecified material properties for part and complementary contours characterised in that the layers (L) are sliced, as by software from a 3-D computer model representation of the part into a plurality of successive layers (L) corresponding to layers of predetermined thickness of the part to effect the generation of said sequences of part and complementary support material contours corresponding to each of said layers, removing portions of said material(s) from said contour(s) under the control of the computer model contour(s) corresponding thereto; repeating the depositing, processing, and removing as necessary under the control of the computer model corresponding to the layer (L) to complete an aggregate layer comprising part material contours within prespecified geometric and material property tolerances and complementary material(s) elsewhere on the aggregate layer; completing the computer model layer by further processing said aggregate layer to ensure thickness tolerances and selective binding to the next aggregate layer; repeating said controlled layer creation steps to build the entire part surrounded by the complementary material/s; and removing said complementary material/s to obtain the fabricated part.
2. The method of claim 1 wherein the processing of said three-dimensional computer model into contours is done in a batch mode to obtain a full set of contours.
3. The method of claim 1 wherein the processing of said three-dimensional computer model for a given contour is performed as said given contour is needed by the process, with the slicing of the model occurring simultaneously with the part building.
4. A method as claimed in claim 1 and in which the materials deposition is effected upon a pre-cut mask of complementary material, the cut of which corresponds to a corresponding software-slice contour, such that the mask is left in place as complementary support material toward the formation of the aggregate layer.
5. A method of claim 1 and in which the materials deposition is effected upon a pre-cut mask of material other than complementary material, and is removed prior to the formation of the aggregate layer.
6. The method of claim 1 in which the precut masks are machined frames on a continuous film that advances over the work surface, or machined individual sheets that are sequentially positioned over the work surface.
7. The method of claim 1 in which the mask forming system consists of a conventional machining or a laser/energy beam machining system.
8. The method of claim 1 wherein the part and/or complementary sections which form the aggregate layer may consist of multiple materials.