Accurate Tool Path Generation Method for Large-Scale Discrete Shapes

2019 ◽  
Vol 13 (2) ◽  
pp. 279-288 ◽  
Author(s):  
Hiromu Kitahara ◽  
Jun’ichi Kaneko ◽  
Masahiro Ajisaka ◽  
Takeyuki Abe ◽  
Kenichiro Horio ◽  
...  

Three-axis ball end mills are used for the finishing of metal molds of complicated curved surfaces. Typically, a tool path of this shape machining is derived from the geometric calculations of a tool used, and a product model that is a computer aided design (CAD)-based polyhedron approximating the shape. The polyhedron is more complicated to approximate a shape with more curved surfaces, as it is highly time consuming. To solve this problem, methods to accelerate geometric calculations using a computer graphics drawing processing mechanism were proposed. However, these methods cannot guard against errors arising from the approximation of an inverse offset shape using a set of polygons. In the present study, we propose a method to generate tool paths accurately based on calculating the crossing points of the tool axis and defining the offset surface as a set of polygons, cylindrical surfaces, and spherical surfaces. With this method, it is expected that the height of an area, which was divided by fine polygons in previous methods, can be derived accurately, and a tool path can be generated with high precision.

2013 ◽  
Vol 282 ◽  
pp. 235-241 ◽  
Author(s):  
Ján Semjon ◽  
Peter Demeč ◽  
Jozef Svetlík

This article focuses on issue of proposal ideal tool paths for machine tools. Model of machine consists from 6 basic knots where milling machine disposes spindle placed in the horizontal direction are. Based on mathematical analysis we can detect the movement of machine axes for uncertainty investigated. The calculated values can be compared with machine model developed in Computer - Aided Design. Defining the shape of workpiece as well as assigning an appropriate instrument can be determined by true value of precision workpiece. After substituting the values of specific dimensions we get the final position of vectors point for contact in tool coordinate systems at individual model solids.


2015 ◽  
Vol 76 (6) ◽  
Author(s):  
Dzullijah Ibrahim ◽  
Zahurin Samad ◽  
Yusli Yaakob ◽  
Norasikin Hussin ◽  
Siti Mardini Binti Hashim

Standard for Exchange of Product Model Data (STEP) is a Standard associated with representation of product data model to enable data communication between different Computer-aided Design (CAD), Computer-aided Manufacturing (CAM) and other engineering systems without any ambiguities and any possible data losses. The development of Open Architecture (PC-based) Numerical Control (OAPC-NC) Interpolator has enhanced the possibilities of data communication between the systems. A tool path data interface to OAPC-NC interpolator is proposed and developed; and a hierarchical-based algorithm is used to extract the tool path data from STEP-NC tool path file of a product model. The generated output of the interpolated data is computer simulated for 3D straight-line path to verify the validity of the interpolator input generated by the proposed interface.


2012 ◽  
Vol 523-524 ◽  
pp. 380-385
Author(s):  
Tatsuya Hokkyo ◽  
Hideki Aoyama ◽  
Noriaki Sano

Generally, ball end mills are used for free-form surface machining. When machining curved surfaces with large curvature change using ball end mills, it is necessary to use tools with larger curvature of the cutting edges than the maximum curvature of the surface and minute pick feeds or to change tools for fitting the curvature of one part of the surface. However this causes poor machining efficiency. The curvature of the cutting edge of a flat end mill can be fitted to the curvature of a point on machined surfaces by adjusting the tool posture. Therefore, flat end mills can efficiently cut almost all curvature curved surfaces without tool change. This paper proposes two methods for deciding tool posture and tool path for 5-axis control machining based on minimum cusp height. To decide the tool path, one method defines tool paths along isoparametric curved lines, while the other defines tool paths along curved lines along the minimum curvature direction. The basic system was constructed based on the proposed method, and the effectiveness of the proposed method was verified.


Author(s):  
Chao-Yaug Liao ◽  
Jean-Claude Léon ◽  
Cédric Masclet ◽  
Michel Bouriau ◽  
Patrice L. Baldeck ◽  
...  

Based on the two-photon polymerization technique, an analysis of product shapes is performed so that their digital manufacturing models can be efficiently processed for micromanufacture. To describe microstructures, this analysis shows that nonmanifold models are of interest. These models can be intuitively understood as combinations of wires, surfaces, and volumes. Minimum acceptable wall thickness, wire dimension, and laser density of energy are among the elements justifying this category of models. Taking into account this requirement, a model preparation and processing scheme is proposed that widens the laser beam trajectories with a concept of extended layer manufacturing technique. A tessellation process suited for non-manifold models has been developed for computer-aided design models imported from standard for the exchange of product files. After tessellation, several polyhedral subdomains form a nonmanifold polyhedron. To plan the trajectories of the laser beam, adaptive slicing and global 3D hatching processes as well as a “welding” process (for joining subdomains of different dimensionality) have been combined. Finally, two nonmanifold microstructures are fabricated according to the proposed model preparation and processing scheme.


2018 ◽  
Vol Vol.18 (No.1) ◽  
pp. 96-107 ◽  
Author(s):  
Lam NGUYEN ◽  
Johannes BUHL ◽  
Markus BAMBACH

Three-axis machines are limited in the production of geometrical features in powder-bed additive manufacturing processes. In case of overhangs, support material has to be added due to the nature of the process, which causes some disadvantages. Robot-based wire-arc additive manufacturing (WAAM) is able to fabricate overhangs without adding support material. Hence, build time, waste of material, and post-processing might be reduced considerably. In order to make full use of multi-axis advantages, slicing strategies are needed. To this end, the CAD (computer-aided design) model of the part to be built is first partitioned into sub-parts, and for each sub-part, an individual build direction is identified. Path planning for these sub-parts by slicing then enables to produce the parts. This study presents a heuristic method to deal with the decomposition of CAD models and build direction identification for sub-entities. The geometric data of two adjacent slices are analyzed to construct centroidal axes. These centroidal axes are used to navigate the slicing and building processes. A case study and experiments are presented to exemplify the algorithm.


2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun

Abstract The improvement of ultra-precision machining technology has significantly boosted the demand for the surface quality and surface accuracy of the workpieces to be machined. However, the geometric shapes of workpiece surfaces cannot be adequately manufactured with simple plane, cylindrical, or spherical surfaces because of their different applications in various fields. In this research, a method was proposed to generate tool paths for the machining of complex spherical surfaces based on an ultra-precise five-axis turning and milling machine with a C-Y-Z-X-B structure. Through the proposed tool path generation method, ultra-precise complex spherical surface machining was achieved. First, the complex spherical surface model was modeled and calculated, and then it was combined with the designed model to generate the tool path. Then the tool paths were generated with a numerically controlled (NC) program. Based on an ultra-precision three-coordinate measuring instrument and a white light interferometer, the machining accuracy of a workpiece surface was characterized, and t[1]he effectiveness of the provided tool path generation method was verified. The surface roughness of the machined workpiece was less than 90 nm. Furthermore, the surface roughness within the spherical region appeared to be less than 30 nm. The presented tool path generation method in this research produced ultra-precision spherical complex surfaces. The method could be applied to complex spherical surfaces with other characteristics.


Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1181 ◽  
Author(s):  
José Ignacio Rojas-Sola ◽  
David Hernández-Díaz ◽  
Ricardo Villar-Ribera ◽  
Vicente Hernández-Abad ◽  
Francisco Hernández-Abad

This article presents evidence of the convenience of implementing the geometric places of the plane into commercial computer-aided design (CAD) software as auxiliary tools in the computer-aided sketching process. Additionally, the research considers the possibility of adding several intuitive spatial geometric places to improve the efficiency of the three-dimensional geometric design. For demonstrative purposes, four examples are presented. A two-dimensional figure positioned on the flat face of an object shows the significant improvement over tools currently available in commercial CAD software, both vector and parametric: it is more intuitive and does not require the designer to execute as many operations. Two more complex three-dimensional examples are presented to show how the use of spatial geometric places, implemented as CAD software functions, would be an effective and highly intuitive tool. Using these functions produces auxiliary curved surfaces with points whose notable features are a significant innovation. A final example provided solves a geometric place problem using own software designed for this purpose. The proposal to incorporate geometric places into CAD software would lead to a significant improvement in the field of computational geometry. Consequently, the incorporation of geometric places into CAD software could increase technical-design productivity by eliminating some intermediate operations, such as symmetry, among others, and improving the geometry training of less skilled users.


2020 ◽  
Vol 7 (5) ◽  
pp. 603-614 ◽  
Author(s):  
Mutahar Safdar ◽  
Tahir Abbas Jauhar ◽  
Youngki Kim ◽  
Hanra Lee ◽  
Chiho Noh ◽  
...  

Abstract Feature-based translation of computer-aided design (CAD) models allows designers to preserve the modeling history as a series of modeling operations. Modeling operations or features contain information that is required to modify CAD models to create different variants. Conventional formats, including the standard for the exchange of product model data or the initial graphics exchange specification, cannot preserve design intent and only geometric models can be exchanged. As a result, it is not possible to modify these models after their exchange. Macro-parametric approach (MPA) is a method for exchanging feature-based CAD models among heterogeneous CAD systems. TransCAD, a CAD system for inter-CAD translation, is based on this approach. Translators based on MPA were implemented and tested for exchange between two commercial CAD systems. The issues found during the test rallies are reported and analyzed in this work. MPA can be further extended to remaining features and constraints for exchange between commercial CAD systems.


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