Piecewise Arc Length Parameterized Nurbs Tool Paths Generation For 3 Axis Cnc Machining Of Accurate Smooth Sculptured Surfaces
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Piecewise Arc Length Parameterized Nurbs Tool Paths Generation For 3 Axis Cnc Machining Of Accurate Smooth Sculptured Surfaces
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Author : Maqsood Ahmed Khan
language : en
Publisher:
Release Date : 2010
Piecewise Arc Length Parameterized Nurbs Tool Paths Generation For 3 Axis Cnc Machining Of Accurate Smooth Sculptured Surfaces written by Maqsood Ahmed Khan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
In current industrial applications many engineering parts having complex shapes are designed using sculptured surfaces in CAD system. Due to the lack of smooth motions and accurate machining of these surfaces using standard linear and circular motions in conventional CNC machines, new commercial CNC systems are equipped with parametric curve interpolation function. However, in some applications these surfaces can be very complex that are susceptible to gouging and due to the approximation of; CL-path in CAM system and path parameter in real-time, high machining accuracy, smooth kinematic and feed-rate profiles, are difficult to achieve. This dissertation focuses on developing algorithms that generate tool paths in NURBS form for smooth, high speed and accurate sculptured surface machining. The first part of the research identifies and eliminates gouge cutter location (CL) point from the tool path. The proposed algorithm uses global optimization technique (Particle Swarm Optimization) to check all the CC-points along a tool-path with high accuracy, and only gouging free CC-points are used to generate the set of valid CL-points. Mathematical models have been developed and implemented to cover most of the cutter shapes, used in the industry. In the second phase of the research, all valid CL-points along the tool-path are used to generate CL-path in B-spline form. The main contribution of this part is to formulate an error function of the offset approximation and to represent it in NURBS form to globally bound the approximation errors. Based on this error function, an algorithm is proposed to generate tool-paths in B-spline from with; globally controlled accuracy, fewer control points and low function degree, compared to its contemporaries. The proposed approach thus presents an error-bounded method for B-spline curve approximation to the ideal CL-path within the accuracy. This part of research has two components, one is for 2 1/2- axis (pocket) and the other one is for 3-axis (surface) CNC machining. The third part deals with the problem of CL-path parameter estimation during machining in real time. Once the gouging free CL-path in NURBS form with globally controlled accuracy is produced, it is re-parameterized with approximate arc-length in the off-line stage. The main features of this work are; (1) sampling points and calculating their approximate arc-lengths within error bound by decomposing the input path into Bezier curve segments, (2) fitting the NURBS curve with approximate arc-length parameter to the sample points until the path and parameterization errors are within the tolerance, and (3) segment the curve into pieces with different feed rates if during machining the cutter trajectory errors are beyond the tolerance at highly curved regions in the NURBS tool path.
Arc Length Parameterized Nurbs Tool Path Generation And Velocity Profile Planning For Accurate 3 Axis Curve Milling
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Author : Yangtao Li
language : en
Publisher:
Release Date : 2012
Arc Length Parameterized Nurbs Tool Path Generation And Velocity Profile Planning For Accurate 3 Axis Curve Milling written by Yangtao Li and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Specification And Implementation Of Time Optimal Feedrates For Curved Tool Paths In 3 Axis Machining
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Author : Sebastian D. Timar
language : en
Publisher:
Release Date : 2001
Specification And Implementation Of Time Optimal Feedrates For Curved Tool Paths In 3 Axis Machining written by Sebastian D. Timar and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
Non Constant Parameter Tool Path Generation For 5 Axis Milling Of Sculptured Surfaces Using A Toroidal End Mill
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Author : Amitabh Anant Khare
language : en
Publisher:
Release Date : 1997
Non Constant Parameter Tool Path Generation For 5 Axis Milling Of Sculptured Surfaces Using A Toroidal End Mill written by Amitabh Anant Khare and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with categories.
The use of complex or sculptured surfaces to define object boundaries is universally acclaimed in today's industry. Specific applications, design requirements, industrial arts and aesthetics are some of industry's requirements that necessitate the use of sculptured surfaces in the representation of a product. Till recently industry relied mostly on 3-axis milling machines using a variety of milling cutters to machine sculptured surfaces. The need for reducing machining time, production cost and improving machining quality led to the development of 5-axis milling machines. This research proposes the use of toroidal or filleted end mills to overcome the problem of limited range of curvatures available on a tool, while making use of surface characteristics to achieve optimum cutter contact. The tool path generation technique followed in this research is a non-constant parameter offset tool path as opposed to constant parameter offset tool path. This ensures that the surface is not over machined thereby reducing machining time.
Minimum Error Tool Path Generation Method And An Interpolator Design Technique For Ultra Precision Multiaxis Cnc Machining
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Author :
language : en
Publisher:
Release Date : 1999
Minimum Error Tool Path Generation Method And An Interpolator Design Technique For Ultra Precision Multiaxis Cnc Machining written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with categories.
Smooth And Time Optimal Trajectory Generation For High Speed Machine Tools
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Author : Michele Mei-Ting Heng
language : en
Publisher:
Release Date : 2008
Smooth And Time Optimal Trajectory Generation For High Speed Machine Tools written by Michele Mei-Ting Heng and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with categories.
In machining complex dies, molds, aerospace and automotive parts, or biomedical components, it is crucial to minimize the cycle time, which reduces costs, while preserving the quality and tolerance integrity of the part being produced. To meet the demands for high quality finishes and low production costs in machining parts with complex geometry, computer numerical control (CNC) machine tools must be equipped with spline interpolation, feedrate modulation, and feedrate optimization capabilities. This thesis presents the development of novel trajectory generation algorithms for Non Uniform Rational B-Spline (NURBS) toolpaths that can be implemented on new low-cost CNC's, as well as, in conjunction with existing CNC's. In order to minimize feedrate fluctuations during the interpolation of NURBS toolpaths, the concept of the feed correction polynomial is applied. Feedrate fluctuations are reduced from around 40 % for natural interpolation to 0.1 % for interpolation with feed correction. Excessive acceleration and jerk in the axes are also avoided. To generate jerk-limited feed motion profiles for long segmented toolpaths, a generalized framework for feedrate modulation, based on the S-curve function, is presented. Kinematic compatibility conditions are derived to ensure that the position, velocity, and acceleration profiles are continuous and that the jerk is limited in all axes. This framework serves as the foundation for the proposed heuristic feedrate optimization strategy in this thesis. Using analytically derived kinematic compatibility equations and an efficient bisection search algorithm, the command feedrate for each segment is maximized. Feasible solutions must satisfy the optimization constraints on the velocity, control signal (i.e. actuation torque), and jerk in each axis throughout the trajectory. The maximized feedrates are used to generate near-optimal feed profiles that have shorter cycle times, approximately 13-26% faster than the feed profiles obtained using the worst-case curvature approach, which is widely used in industrial CNC interpolators. The effectiveness of the NURBS interpolation, feedrate modulation and feedrate optimization techniques has been verified in 3-axis machining experiments of a biomedical implant.
Shape Interrogation For Computer Aided Design And Manufacturing
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Author : Nicholas M. Patrikalakis
language : en
Publisher: Springer Science & Business Media
Release Date : 2002-02-14
Shape Interrogation For Computer Aided Design And Manufacturing written by Nicholas M. Patrikalakis and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002-02-14 with Computers categories.
Shape interrogation is the process of extraction of information from a geometric model. It is a fundamental component of Computer Aided Design and Manufacturing (CAD/CAM) systems. The authors focus on shape interrogation of geometric models bounded by free-form surfaces. Free-form surfaces, also called sculptured surfaces, are widely used in the bodies of ships, automobiles and aircraft, which have both functionality and attractive shape requirements. Many electronic devices as well as consumer products are designed with aesthetic shapes, which involve free-form surfaces. This book provides the mathematical fundamentals as well as algorithms for various shape interrogation methods including nonlinear polynomial solvers, intersection problems, differential geometry of intersection curves, distance functions, curve and surface interrogation, umbilics and lines of curvature, geodesics, and offset curves and surfaces. This book will be of interest both to graduate students and professionals.
Theory And Design Of Cnc Systems
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Author : Suk-Hwan Suh
language : en
Publisher: Springer Science & Business Media
Release Date : 2008-08-22
Theory And Design Of Cnc Systems written by Suk-Hwan Suh and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-08-22 with Technology & Engineering categories.
Computer Numerical Control (CNC) controllers are high value-added products counting for over 30% of the price of machine tools. The development of CNC technology depends on the integration of technologies from many different industries, and requires strategic long-term support. “Theory and Design of CNC Systems” covers the elements of control, the design of control systems, and modern open-architecture control systems. Topics covered include Numerical Control Kernel (NCK) design of CNC, Programmable Logic Control (PLC), and the Man-Machine Interface (MMI), as well as the major modules for the development of conversational programming methods. The concepts and primary elements of STEP-NC are also introduced. A collaboration of several authors with considerable experience in CNC development, education, and research, this highly focused textbook on the principles and development technologies of CNC controllers can also be used as a guide for those working on CNC development in industry.
Parallel Kinematics
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Author : Xin-Jun Liu
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-08-15
Parallel Kinematics written by Xin-Jun Liu and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-08-15 with Technology & Engineering categories.
Parallel Kinematics- Type, Kinematics, and Optimal Design presents the results of 15 year's research on parallel mechanisms and parallel kinematics machines. This book covers the systematic classification of parallel mechanisms (PMs) as well as providing a large number of mechanical architectures of PMs available for use in practical applications. It focuses on the kinematic design of parallel robots. One successful application of parallel mechanisms in the field of machine tools, which is also called parallel kinematics machines, has been the emerging trend in advanced machine tools. The book describes not only the main aspects and important topics in parallel kinematics, but also references novel concepts and approaches, i.e. type synthesis based on evolution, performance evaluation and optimization based on screw theory, singularity model taking into account motion and force transmissibility, and others. This book is intended for researchers, scientists, engineers and postgraduates or above with interests in robotics and advanced machine tools technology such as parallel kinematics machines (PKMs). Xinjun Liu and Jinsong Wang, professors, work at The Institute of Manufacturing Engineering, Department of Precision Instruments and Mechanology, Tsinghua University.
Pythagorean Hodograph Curves Algebra And Geometry Inseparable
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Author : Rida T Farouki
language : en
Publisher: Springer Science & Business Media
Release Date : 2008-02-01
Pythagorean Hodograph Curves Algebra And Geometry Inseparable written by Rida T Farouki and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-02-01 with Mathematics categories.
By virtue of their special algebraic structures, Pythagorean-hodograph (PH) curves offer unique advantages for computer-aided design and manufacturing, robotics, motion control, path planning, computer graphics, animation, and related fields. This book offers a comprehensive and self-contained treatment of the mathematical theory of PH curves, including algorithms for their construction and examples of their practical applications. It emphasizes the interplay of ideas from algebra and geometry and their historical origins and includes many figures, worked examples, and detailed algorithm descriptions.