A Voxel Model-Based Process-Planning Method for Five-Axis Machining of Complicated Parts

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Yamin Li ◽  
Kai Tang ◽  
Long Zeng
Keyword(s):  
Process Planning ◽  
Planning Method ◽  
Dynamic Problems ◽  
Tool Paths ◽  
New Process ◽  
Part Surface ◽  
Voxel Model ◽  
Voxel Representation ◽  
Complex Features ◽  
Five Axis

Abstract This paper presents a new process planning method for five-axis machining, which is particularly suitable for parts with complex features or weak structures. First, we represent the in-process workpiece as a voxel model. Facilitated by the voxel representation, a scalar field called subtraction field is then established between the blank surface and the part surface, whose value at any voxel identifies its removal sequence. This subtraction field helps identify a sequence of intermediate machining layers, which are always accessible to the tool and are free of self-intersection and the layer redundancy problem as suffered, respectively, by the traditional offset layering method and the morphing method. Iso-planar collision-free five-axis tool paths are then determined on the interface surfaces of these machining layers. In addition, to mitigate the deformation of the in-process workpiece and avoid potential dynamic problems such as chattering, we also propose a new machining strategy of alternating between the roughing and finishing operations, which is able to achieve a much higher stiffness of the in-process workpiece. Ample experiments in both computer simulation and physical cutting are performed, and the experimental results convincingly confirm the advantages of our method.

Process planning based on cylindrical or conical surfaces for five-axis wire and arc additive manufacturing

2020 ◽  
Vol 26 (8) ◽  
pp. 1405-1420
Author(s):  
Fusheng Dai ◽  
Haiou Zhang ◽  
Runsheng Li
Keyword(s):  
Additive Manufacturing ◽  
Path Planning ◽  
Process Planning ◽  
Flat Surface ◽  
Welding Process ◽  
Planning Method ◽  
Content Type ◽  
Tool Paths ◽  
Conical Surfaces ◽  
Five Axis

Purpose The study aims to fabricate large metal components with overhangs built on cylindrical or conical surfaces with a high dimensional precision. It proposes methods to address the problems of generating tool-paths on cylindrical or conical surfaces simply and precisely, and planning the welding process on these developable surfaces. Design/methodology/approach The paper presents the algorithm of tool-paths planning on conical surfaces using a parametric slicing equation and a spatial mapping method and deduces the algorithm of five-axis transformation by addressing the rotating question of two sequential points. The welding process is investigated with a regression fitting model on a flat surface, and experimented on a conical surface, which can be flattened onto a flat surface. Findings The paper provides slicing and path-mapping expressions for cylindrical and conical surfaces and a curvature-speed-width (CSW) model for wire and arc additive manufacturing to improve the surface appearances. The path-planning method and CSW model can be applied in the five-axis fabrication of the prototype of an underwater thruster. The CSW model has a confidence coefficient of 98.02% and root mean squared error of 0.2777 mm. The reverse measuring of the finished blades shows the residual deformation: an average positive deformation of about 0.5546 mm on one side of the blades and an average negative deformation of about −0.4718 mm on the other side. Research limitations/implications Because of the chosen research approach, the research results may lack generalizability for the fabrication based on arbitrary surfaces. Originality/value This paper presented an integrated slicing, tool-path planning and welding process planning method for five-axis wire and arc additive manufacturing.

Geodesic Distance Field-based Process Planning for Five-Axis Machining of Complicated Parts

2020 ◽  
pp. 1-27
Author(s):  
Dong He ◽  
Yamin Li ◽  
Zhaoyu Li ◽  
Kai Tang
Keyword(s):  
Process Planning ◽  
Geodesic Distance ◽  
Machining Process ◽  
Rough Machining ◽  
Distance Field ◽  
Tool Paths ◽  
Solid Part ◽  
Level Method ◽  
Machining Operations ◽  
Five Axis

Abstract A critical task in multi-pass process planning for five-axis machining of complicated parts is to determine the intermediate surfaces for rough machining. Traditionally, the intermediate surfaces are simply parallel Z-level planes, and the machining is of the simplest three-axis type. However, for complicated parts, this so-called Z-level method lacks flexibility and causes isolated islands on layers, which require extraneous air movements by the tool. Moreover, the in-process workpiece machined according to the Z-level method suffers from the staircase effect, which often induces unstable dynamic problems on the tool-spindle system. In this paper, we propose a new method of planning a five-axis machining process for a complicated freeform solid part. In our method, the intermediate surfaces are no longer planar but curved, and they are intrinsically influenced by the convex hull of the part. The powerful algebraic tool of geodesic distance field is utilized to generate the desired intermediate surfaces, for which collision-free five-axis machining tool paths are then planned. In addition, we propose a novel idea of alternating between the roughing and finishing machining operations, which helps improve the stiffness of the in-process workpiece. Ample physical cutting experiments are performed, and the experimental results convincingly confirm the advantages of our method.

Five-Axis Part Machining With Three-Axis CNC Machine and Indexing Table

1998 ◽  
Vol 120 (1) ◽  
pp. 120-128 ◽  
Author(s):  
Suk-Hwan Suh ◽  
Jung-Jae Lee
Keyword(s):  
Tool Path ◽  
Solution Procedure ◽  
Algebraic Solution ◽  
Cnc Machine ◽  
Tool Paths ◽  
Path Computation ◽  
Part Surface ◽  
Five Axis ◽  
Surface Decomposition ◽  
Index Table

In this paper, we develop a versatile CAM method by which five axis machining can be effectively carried out with a three-axis CNC machine together with a rotary-tilt type indexing table. In this method, the part surface is divided into a set of subareas, and each subarea is machined by the virtually oriented tool whose orientation is provided via the index table. The key goal in developing our solution algorithm has been to minimizing the number of part setups (i.e., angle changes in the indexing table) and the surface ridges where multiple tool paths join. A robust algebraic solution procedure for achieving these practical criteria is presented, including the details of surface decomposition, tool path computation, and the interface of the index table. Since the developed method enables utilization of existing machines (equipped with three-axis control) for five-axis machining, the results are practically meaningful, especially for small to medium industries.

Research on Process Planning Method of NC Tube Bending

2011 ◽  
Vol 411 ◽  
pp. 393-397 ◽  
Author(s):  
Jin Rong Zhang ◽  
Feng Li ◽  
Qiang Zhu ◽  
Yong Jun Wang
Keyword(s):  
Process Planning ◽  
Planning Process ◽  
Process Analysis ◽  
Planning Method ◽  
Tube Bending ◽  
Factors Affecting ◽  
Bending Process ◽  
New Process ◽  
Optimal Set

In order to improve efficiency and quality of tube process, a new process planning method for NC tub bending is proposed. Factors affecting NC tube bending process is firstly discussed, and NC bending process planning is also achieved by theoretical process set calculation, occurrence of interference processes set analysis, clamping difficult process analysis and optimal set of processes selection. The method above is effective and useful for planning process of the complex tube bending parts.

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.

Study of The Tool Path Generation Method of an Ultra-Precision Spherical Complex Surface Based on a Five-Axis Machine Tool

2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun
Keyword(s):  
Surface Roughness ◽  
Tool Path ◽  
Spherical Surface ◽  
Tool Path Generation ◽  
Path Generation ◽  
Tool Paths ◽  
Spherical Surfaces ◽  
Spherical Complex ◽  
Ultra Precision ◽  
Five Axis

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.

A Process Planning Method for Improving the Build Performance in Stereolithography

1999 ◽  
Author(s):  
Aaron P. West ◽  
David W. Rosen
Keyword(s):  
Process Planning ◽  
Planning Method ◽  
Analytical Models ◽  
Multi Objective Optimization ◽  
Process Variables ◽  
Build Time ◽  
Insight Into ◽  
Conflicting Goals ◽  
Selection Of

Abstract A process planning method is presented in this paper to aid stereolithography users in the selection of appropriate values of build process variables in order to achieve specific goals and characteristics that are desirable in the end prototype. To accomplish this, user-defined input in the form of goal preferences and feature tolerances are used to control how the prototype will be built by way of process planning. The user inputs will be used to drive the creation of the process plan so that a prototype is produced, which reflects the intent of the operator. The process planning method is adapted from multi-objective optimization and utilizes empirical data, analytical models, and heuristics to quantitatively relate build process variables to goals of surface finish, accuracy, and build time. The objective is to render decision support by handling tradeoffs among conflicting goals quantitatively and give the user some degree of insight into what quality of prototype may ultimately be produced. The process planning method is demonstrated on a part with non-trivial geometric features.

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