A semi‐analytic approach for direct slicing of free form surfaces for layered manufacturing

Abstract

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -This paper aims to develop an efficient surface-plane intersection (SPI) algorithm for direct slicing of free-form surfaces to be produced by layered manufacturing. Design/methodology/approach -A semi-analytical method for direct slicing has been formulated and tested on Bezier and B-spline surfaces commonly used in CAD modeling. This method solves for the intersection points by a "root" finding procedure and establishes their connectivity, unlike the conventional "marching" procedures. Findings -The proposed algorithm solves intersection contours between free form surfaces and planes. The solution procedure is efficient with respect to computational time and accuracy (feature detection) over some of the conventional SPI strategies. The method involves a global solution procedure in contention with the traditional methodologies which are generally spatially distinctive in approach.Research limitations/implications -Use of higher order terms in the representation of parametric surfaces makes the algorithm computationally intensive and time-expensive. Practical implications -This algorithm would be of practical use in the direct slicing of free form surfaces used in CAD modeling. Direct slicing methods solve for the actual intersection of surface and plane without resorting to "tessellation." Reducing the computation time and detection of features within a given resolution is of primary importance for developing commercial rapid prototyping software, which is achieved in the present paper. Originality/value -A novel method has been developed for SPI for use in direct slicing of CAD models. While a major proportion of the direct slicing strategies employ the "marching" procedure involving determination of "critical points," the proposed method utilizes the evaluation of "roots" of a surface in a global manner to determine the intersection points with proper connectivity. Hence, it is effective in reducing the computation time and is simple but generic in approach. Although Bezier and B-spline surfaces are used as the representative cases, the algorithm can be extended for any parametric surface for direct slicing.

Comparing Slicing Technologies for Digital Light Processing Printing

“…They have different time complexity depending on the mesh size and the number of layers. To speed up the slicing process, the mesh faces can be sorted to reduce the number of faces need to be intersected [7], and others developed information reuse in the context of customization [8] or applied adaptive slicing to reduce the number of layers [9]. After the contours are generated, the infill pattern can be generated within them [10,11].…”

Efficient slicing procedure based on adaptive layer depth normal image

“…For NURBS models, Rajagopalan et al [11] proposed a direct slicing method using the complete geometric representation. For freeform surfaces, Chakraborty et al [12] output a layered file directly based on a surface-plane intersection algorithm. For point cloud models, Liu et al [13] proposed an error-based segmentation method for direct RP.…”

Visual Perception and Overlay Welding Motion Planning for the Cross-section of Bulkhead in Steam Turbine

“…[22] developed a layering system that takes STEP format as input, uses OpenGL to display the solid model, and specifies the layer thickness for direct layering of CAD models. Chakraborty D. [23] proposed a semianalytical method for direct layering specifically targeting commonly used B-spline and Bezier surfaces in CAD modeling. However, most of the aforementioned methods rely on high-precision models or high-precision sensors, and consider the situation where the model is lacking to a lesser extent.…”