Computation of Optimal Workpiece Orientation for Multi-axis NC Machining of Sculptured Part Surfaces

2002 ◽  
Vol 124 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Stephen P. Radzevich ◽  
Erik D. Goodman
Keyword(s):  
Cutting Tool ◽  
Nc Machining ◽  
Numerical Control ◽  
Tool Geometry ◽  
Geometric Problem ◽  
Part Surface ◽  
Nc Machine ◽  
New Type ◽  
Five Axis ◽  
Workpiece Orientation

Optimal workpiece orientation for multi-axis sculptured part surface machining is generally defined as orientation of the workpiece so as to minimize the number of setups in 4-, 5- or more axis Numerical Control (NC) machining, or to allow the maximal number of surfaces to be machined in a single setup on a three-, four-, or five-axis NC machine. This paper presents a method for computing such an optimal workpiece orientation based on the geometry of the part surface to be machined, of the machining surface of the tool, and of the degrees of freedom available on the multi-axis NC machine. However, for cases in which some freedom of orientation remains after conditions for machining in a single setup are satisfied, a second sort of optimality can also be considered: finding an orientation such that the cutting condition (relative orientation of the tool axis and the normal to the desired part surface) remains as constant, at some optimal angle, as possible. This second form of optimality is obtained by choosing an orientation (within the bounds of those allowing a single setup) in which the angle between the neutral axis of the milling tool and the area-weighted mean normal to the part surface, at a “central” point with a normal in that mean direction, is zero, or as small as possible. To find this solution, Gaussian maps (GMap) of the part surfaces to be machined and the machining surface of the tool are applied. To our knowledge, we are the first [1] who have picked up this Gauss’ idea to sculptured part surface orientation problem and who have developed the general approach to solve this important engineering problem [2]. Later a similar approach was claimed by Gan [3]. By means of GMaps of these surfaces, the problem of optimal workpiece orientation can be formulated as a geometric problem on a sphere. The GMap on a unit sphere finds wide application for orientation of workpiece for NC machining, for probing on coordinate measuring machines, etc. GMaps are useful for selecting the type of cutting tool, its path, workpiece fixturing, and the type of NC machine (its kinematic capabilities). The primary process application addressed is 3- and 4-axis NC milling, although the techniques presented may be applied to machines with more general articulation. The influence of tool geometry is also discussed and incorporated within a constrained orientation algorithm. This paper covers the following topics: a) the derivation of the equations of the GMap of the part surface to be machined and the machining surface of the tool; b) calculation of the parameters of the weighted normal to the part surface; c) optimal part orientation on the table of a multi-axis NC machine; d) introduction of a new type of GMap for a sculptured part surface—its expandedGMapE; and e) introduction of a new type of indicatrix of a sculptured part surface and a particular cutting tool–the indicatrix of machinability.

Interference-Free Multi-Axis NC Machining of Cylindrical Cam Using Enveloping Element

2009 ◽  
Vol 419-420 ◽  
pp. 333-336
Author(s):  
Jeng Nan Lee ◽  
Chih Wen Luo ◽  
Hung Shyong Chen
Keyword(s):  
Cutting Tool ◽  
Nc Machining ◽  
Model Material ◽  
Solid Model ◽  
End Mill ◽  
Generating Method ◽  
Collision Problem ◽  
Five Axis ◽  
Cutting Path ◽  
Cutting Simulations

To obtain the flexibility of choice of cutting tool and to compensate the wear of the cutting tool, this paper presents an interference-free toolpath generating method for multi-axis machining of a cylindrical cam. The notion of the proposed method is that the cutting tool is confined within the meshing element and the motion of the cutting tool follows the meshing element so that collision problem can be avoided. Based on the envelope theory, homogeneous coordinate transformation and differential geometry, the cutter location for multi-axis NC machining using cylindrical-end mill is derived and the cutting path sequences with the minimum lead in and lead out are planned. The cutting simulations with solid model are performed to verify the proposed toolpath generation method. It is also verified through the trial cut with model material on a five-axis machine tool.

A Servo Control Scheme of the Integrated NC Machine of Pipe Fitting

2013 ◽  
Vol 475-476 ◽  
pp. 689-692
Author(s):  
Cong Wang ◽  
Jing Chen ◽  
You Xin Yuan ◽  
Yi Deng ◽  
Xiao Bin Long
Keyword(s):  
Nc Machining ◽  
Servo Control ◽  
Numerical Control ◽  
Pipe Fitting ◽  
Water Heater ◽  
Machining Processes ◽  
Forming Process ◽  
Automatic Integration ◽  
Control Scheme ◽  
Nc Machine

The current pipe fitting forming process is characterized by more than one equipment and gradually formation processes. Therefore, a servo control scheme of the integrated NC machine of pipe fitting is designed. The following works have been done: design the integrated NC machining processes and structure, and design a novel servo control scheme for the machining equipment. The automatic integration processing of pipe fittings is operated by the SCC control system. It could fulfill the integration NC machining and any combination of processing just by putting the pipe into the entrance of the machine artificially. The integrated equipment can realize the integrated numerical control, combine the whole processes willfully, and enhance the process quality. This scheme can be used for the pipe fitting forming in the air conditioning, the water heater, the refrigerator, or the automotive industry.

Five-Axis Swept Volumes for Graphic NC Simulation and Verification

1989 ◽  
Author(s):  
K. Sambandan ◽  
K. K. Wang
Keyword(s):  
Nc Machining ◽  
Image Space ◽  
Numerical Control ◽  
Mathematical Basis ◽  
Nc Simulation ◽  
Swept Volumes ◽  
Nc Milling ◽  
Depth Buffer ◽  
Swept Volume ◽  
Five Axis

Abstract This paper explains in detail a simulator that has been developed for graphic verification of five-axis Numerical Control (NC) machining. Exact parametric representations for the surfaces generated by common NC milling cutters during five-axis motions have been derived using the theory of envelopes as the mathematical basis. Parts of these surfaces form the boundary of the total swept volume generated. For each cutting motion, the swept volume of the cutter is determined and then subtracted from the stock. The Boolean subtraction is done in the image space at the pixel level, using a modified depth-buffer algorithm. A shaded image of the “as machined” part at the end of each cutting motion is then displayed for verification.

Tool Path Planning for Five-Axis NC Machining of Implant Shaping Mold for Cranioplasty

2011 ◽  
Vol 697-698 ◽  
pp. 292-296
Author(s):  
Liang Zhang ◽  
J. Li ◽  
B.C. Lou
Keyword(s):  
Path Planning ◽  
Tool Path ◽  
Nc Machining ◽  
Normal Curvature ◽  
Tool Path Planning ◽  
Lead Angle ◽  
Tool Axis ◽  
Nc Machine ◽  
Five Axis ◽  
Tool Axis Vector

The necessity for skull patch surface for cranioplasty was introduced and it was divided according to maximum normal curvature in the discrete points after skull patch surface dispersed. Then the tool axis vector was determined by the lead angle of the tool, corresponding to generating the tool path in each area; At last, the implant shaping mold for cranioplasty was produced by five-axis NC machine.

scholarly journals Maximum Intersection of Spherical Polygons and Workpiece Orientation for 4- and 5-Axis Machining

1992 ◽  
Vol 114 (3) ◽  
pp. 477-485 ◽  
Author(s):  
K. Tang ◽  
T. Woo ◽  
J. Gan
Keyword(s):  
Great Circle ◽  
Numerical Control ◽  
Central Projection ◽  
Infinitely Many Solutions ◽  
Curved Surfaces ◽  
Projection Mapping ◽  
Nc Machine ◽  
Workpiece Orientation ◽  
Maximum Intersection

Orienting the workpiece in such a way as to minimize the number of setups in a 4-axis or a 5-axis Numerical Control (NC) machine is formulated as follows: Given a set of spherical polygons (that are representations of curved surfaces visible to a 3-axis NC machine), find a great circle (the 4th axis) or a band (the 4th and the 5th axes) containing a great circle that intersects the polygons maximally. While there are potentially infinitely many solutions to this problem, a sphere is partitioned into O(N2) regions based on the N polygons. Within each of these regions, it is shown that it requires O(NlogN) time to determine maximum intersections and all the solutions are congruent. Central projection mapping is employed so as to present the algorithms in the plane.

The Study of Globoidal Indexing Cam CNC Machine Tools

2013 ◽  
Vol 753-755 ◽  
pp. 888-891
Author(s):  
Tian Xia ◽  
Ling Xu ◽  
Jian Xing Si
Keyword(s):  
Structural Design ◽  
Machine Tools ◽  
Cnc Machine Tools ◽  
Motion Simulation ◽  
Cnc Machine ◽  
Development Status ◽  
Nc Machine Tool ◽  
Nc Machine ◽  
New Type ◽  
Five Axis

Briefly analyzed the development status of the globoidal indexing cam, processing principles and process, put forward the necessity of researching and developing new type NC machine of globoidal indexing cam, the structural design of five-axis linkage NC machine tool of Globoidal indexing Cam. On the basis of using the Solidworks 3D modeling and motion simulation, interference check.

Efficient NC Simulation for Multi-Axis Solid Machining With a Universal APT Cutter

2009 ◽  
Vol 9 (2) ◽  
Author(s):  
Hong-Tzong Yau ◽  
Lee-Sen Tsou
Keyword(s):  
Computer Aided Design ◽  
Numerical Control ◽  
Tool Geometry ◽  
Algebraic Equations ◽  
Sculptured Surfaces ◽  
Simulation Accuracy ◽  
Nc Simulation ◽  
Marching Cube Algorithm ◽  
Voxel Representation ◽  
Five Axis

In multi-axis machining of dies and molds with complex sculptured surfaces, numerical control (NC) simulation/verification is a must for the avoidance of expensive rework and material waste. Despite the fact that NC simulation has been extensively used by industries for many years, efficient, accurate, and reliable view-independent simulation of multi-axis NC machining still remains a difficult challenge. This paper presents the use of adaptive voxel data structure in conjunction with the modeling of a universal cutter for the development of an efficient and reliable multi-axis (typically five-axis) simulation procedure. The octree-based voxel representation of the workpiece saves a significant amount of memory space without sacrificing the simulation accuracy. Rendering of the voxel-based model is view independent and does not suffer from any aliasing effect, due to the real-time triangulation of the boundary surfaces using an extended marching cube algorithm. Implicit algebraic equations are used to model the automatically programed tool geometry, which can represent a universal cutter with high precision. In addition, the proposed method allows users to perform error analysis and gouging detection by comparing the machined surfaces with the original computer-aided design (CAD) model. Illustration of the implementation and experimental results demonstrate that the proposed method is reliable, accurate, and highly efficient.

Motion Accuracy Enhancement of Five-Axis Machine Tools by Modified CL-Data

2018 ◽  
Vol 12 (5) ◽  
pp. 699-706 ◽  
Author(s):  
Ryuta Sato ◽  
Shogo Hasegawa ◽  
Keiichi Shirase ◽  
Masanobu Hasegawa ◽  
Akira Saito ◽  
...  
Keyword(s):  
Machine Tools ◽  
Numerical Control ◽  
Geometrical Shape ◽  
Motion Trajectories ◽  
Shape Errors ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Simulation And Experiment ◽  
Profile Machining ◽  
Five Axis

The motion trajectories of machine tools directly influence the geometrical shape of machined workpieces. Hence, improvement in their motion accuracy is required. It is known that machined shape errors occurring in numerical control (NC) machine tools can be compensated for by modifying the CL-data, based on the amount of error calculated by the measurement results of the machined shape of the workpiece. However, by using this method the shape errors cannot be compensated accurately in five-axis machining, because the final machining shape may not reflect the motion trajectory of a tool owing to the motion errors of the translational and rotary axes. In this study, a modification method of the cutter location (CL)-data, based on the amount of motion errors of the tool center-point trajectory during the machining motion, is newly proposed. The simulation and experiment of a wing profile machining motion is performed, to confirm the effectiveness of the proposed method. From the results, we confirm that the motion accuracy can be significantly improved by applying the proposed method.

Approach to Machining Setup Process Planning of NC Machine Tools Based on Graph Theory

2012 ◽  
Vol 542-543 ◽  
pp. 1190-1195 ◽  
Author(s):  
Guo Zheng Zhang ◽  
Jiang Han ◽  
You Yu Liu
Keyword(s):  
Graph Theory ◽  
Process Planning ◽  
Machine Tools ◽  
Nc Machining ◽  
Numerical Control ◽  
Machining Process ◽  
Fixture Design ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Machining Process Planning

Setup datum of fixture design is an important factor of Numerical Control (NC) machining process planning. Using graph theory of FTG (Feature Tolerance relationship Graph) and DMG (Datum and Machining feature relationship Graph) technology, the feature relationship was proposed to construct a relational table of DMMT (Datum and Machining and Machine Tools) in NC machining setup process. The degree of graph as a discriminant evidence of the machining setup datum was given, so that the machining setup process planning was correctly designed. Combined with the capability of NC machine tools, the unit normal vector of feature facet between the feature datum and machining facet were multiplied to determine the fixture capability, which provide a reasonable proposal of machining setup process for multi-position rotation and multi-piece fixture design. Finally, a case study of machining setup process planning and multi-piece fixture equipment design from corporation was presented to verify the feasibility of the method that was based on the graph theory.

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