Comparison of discretization algorithms for nurbs surfaces with application to numerically controlled machining

Austin, Shawn P.; Jerard, Robert B.; Drysdale, Robert L. Scot

doi:10.1016/s0010-4485(96)00051-6

Cited by 37 publications

(21 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As such, there is a robust body of work relating to populating lattice occupancy grids from continuous surfaces (one overview is [2]). If the lattice voxels are smaller than the machine's discrete steps, then the output will be optimally smooth.…”

Section: Asdfs Versus Bitmapsmentioning

confidence: 99%

Hierarchical volumetric object representations for digital fabrication workflows

Keeter

2013

ACM SIGGRAPH 2013 Posters

View full text Add to dashboard Cite

Modern systems for computer-aided design and manufacturing (CAD/CAM) have a history dating back to drafting boards, early computers, and machine shops with specialized technicians for each stage in a manufacturing workflow. In recent years, personal-scale digital fabrication has challenged many of these workflows' build-in assumptions. A single individual may control the entire workflow, from design to manufacture; they will be using computers that are exponentially more powerful than those in the 1970s; and they may be using a wide variety of tools, machines, and processes.The variety of tools and machines leads to a combinatorial explosion of possible workflows. In addition, tools are based on boundary representations, which are fragile and can easily describe nonsensical objects. This thesis addresses these issues with a set of tools for end-to-end digital fabrication based on volumetric solid models. Workflows are modular, making it easy to add new machines, and a shared core of path-planning operations reduces system complexity. Replacing boundary representations with volumetric representations guarantees that models represent reasonable real-world solids.Adaptively sampled distance fields are used as a generic interchange format. Functional representations are used as a design representation, and we examine scaling behavior and efficient rendering. We present interactive design tools that use these representations as their geometry engine. Data from CT scans is also used to populate these distance fields, showing significant benefits in file size and resolution compared to meshes. Finally, these representations are used as inputs to a modular multimachine CAM workflow. Toolpath generation is implemented, characterized, and tested on a complex solid model. We conclude with a summary of results and recommendations for future research directions.

show abstract

Section: Asdfs Versus Bitmapsmentioning

confidence: 99%

Hierarchical volumetric object representations for digital fabrication workflows

Keeter

2013

ACM SIGGRAPH 2013 Posters

View full text Add to dashboard Cite

show abstract

“…The surfaces were described as bicubic patches and the step size between toolpaths was calculated as a function of local patch properties to ensure an acceptable surface finish. Austin et al [21] compared several discretization strategies employed in the NC machining of NURBS surfaces and concluded that an algorithm based on parametric rectangular subdivision performed best. Sun et al [22] presented work focused specifically on machining free-form surfaces and computing optimal decompositions of the tasks involved to minimize machining time within surface finish and tolerance constraints.…”

Section: Endmilling Toolpath Planningmentioning

confidence: 99%

Improving endmilling surface finish by workpiece rotation and adaptive toolpath spacing

Vijayaraghavan

Hoover

Hartnett

et al. 2009

International Journal of Machine Tools and Manufacture

View full text Add to dashboard Cite

a b s t r a c tFree-form surfaces are being used in a growing number of engineering applications, especially in injection molding of consumer products. Decreasing the manufacturing cost and time of these molds will improve the efficiency of manufacturing injection molded consumer products. This paper is motivated by the need for simple strategies to improve the quality of and decrease the time required to machine free-form surfaces. We present two methods to improve the surface finish of parts finished with ball-nose endmilling. In the first method the surface finish is improved by finding an optimal orientation angle for the workpiece relative to the machining axis. In the second method finish is improved by adaptively varying the step-size when using raster toolpaths. The adaptive variation is controlled by a user-defined finish improvement factor, where the spacing density is increased only if the improvement in surface finish is greater than the finish improvement factor. These methods are implemented using an analytical model of the workpiece surface finish based on the mean scallop height of the machined surface. Results from the analytical model are verified with machining experiments, and we show that the adaptive spacing strategy can improve the surface quality by more than 50% with a small increase in the toolpath length. To achieve a similar improvement in surface quality by uniformly decreasing the path spacing results in a much larger increase in the toolpath length. The strategies discussed in this paper allow process planners intuitive control over the toolpath layout and spacing and improve the efficiency of machining high quality parts.

show abstract

“…There are also some other tool path generation methods such as j^ece curve mcfAwf (Austin et al, 1997;Shah et al, 1991), Ao-cwrvafwre (Jensen and Anderson, 1992), etc.. Extensive reviews on tool path planning maybe found in Marshall and Griffiths (1994), Dragomatz and Mann (1997), Jenson and Anderson (1996), S arma (2000).…”

Section: Prq/ecfkm Cwrvementioning

confidence: 99%

Multiresolution analysis as an approach for tool path planning in NC machining

Narayanaswami

Pang

2003

Computer-Aided Design

View full text Add to dashboard Cite

Comparison of discretization algorithms for nurbs surfaces with application to numerically controlled machining

Cited by 37 publications

References 12 publications

Hierarchical volumetric object representations for digital fabrication workflows

Hierarchical volumetric object representations for digital fabrication workflows

Improving endmilling surface finish by workpiece rotation and adaptive toolpath spacing

Multiresolution analysis as an approach for tool path planning in NC machining

Contact Info

Product

Resources

About