Feed-rate control using fuzzy reasoning for NC machine tools

In this article, a 3D design and machining system based on an NC machine tool with a rotary unit is first introduced to effectively produce attractive paint rollers. A post-processor is proposed to transform a base tool path called cutter location data (CL data) to NC data, mapping the y-directional pick feed to the rotational angle of the rotary unit. The 3D machining system with the postprocessor allows us easily to transcribe a relief design on a flat model surface to a cylindrical model surface. The postprocessor has another function that systematically adjusts the feed-rate according to the curvature of each design to prevent the machined surface from being chipped. The post-processor generates suitable feed-rate codes by using a simple fuzzy reasoning method while checking the edges in relief designs. Experimental results show that wooden paint rollers with attractive relief designs can be successfully machined without undesirable edge chipping. Next, the proposed fuzzy feed-rate generator is further applied to a mold-polishing robot, so that the polishing time can be reduced by about 30% compared with the case without the generator. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

数控刀位轨迹的新算法

CAM中的一个关键技术就是数控刀位轨迹的生成。本文在HANSEN[1]提出的干涉标志量概念及算法基础上，提出了新的理论观点及相应的新算法。新算法用在研制的美术造型图案模腔自动加工成型系统即GNC统中，几年来运行验证效果一直良好。     

Optimizing tool orientations for 5-axis machining by configuration-space search method

This paper presents a methodology and algorithms of optimizing and smoothing the tool orientation control for 5-axis sculptured surface machining. A searching method in the machining configuration space (C-space) is proposed to find the optimal tool orientation by considering the local gouging, rear gouging and global tool collision in machining. Based on the machined surface error analysis, a boundary search method is developed first to find a set of feasible tool orientations in the C-space to eliminate gouging and collision. By using the minimum cusp height as the objective function, we first determine the locally optimal tool orientation in the C-space to minimize the machined surface error. Considering the adjacent part geometry and the alternative feasible tool orientations in the C-space, tool orientations are then globally optimized and smoothed to minimize the dramatic change of tool orientation during machining. The developed method can be used to automate the planning and programming of tool path generation for high performance 5-axis sculptured surface machining. Computer implementation and examples are also provided in the paper.     

A machining potential field approach to tool path generation for multi-axis sculptured surface machining

This paper presents a machining potential field (MPF) method to generate tool paths for multi-axis sculptured surface machining. A machining potential field is constructed by considering both the part geometry and the cutter geometry to represent the machining-oriented information on the part surface for machining planning. The largest feasible machining strip width and the optimal cutting direction at a surface point can be found on the constructed machining potential field. The tool paths can be generated by following the optimal cutting direction. Compared to the traditional iso-parametric and iso-planar path generation methods, the generated MPF multi-axis tool paths can achieve better surface finish with shorter machining time. Feasible cutter sizes and cutter orientations can also be determined by using the MPF method. The developed techniques can be used to automate the multi-axis tool path generation and to improve the machining efficiency of sculptured surface machining.     

Intelligent machining system for the artistic design of wooden paint rollers

In this paper, a 3D design and machining system based on a 3-axis NC machine tool with a rotary unit is introduced to efficiently produce the artistic design of wooden paint rollers. The paint rollers are used to execute a relief wall just after painting. A simple post-processor is first proposed for the NC machine tool to transform a base tool path called cutter location data (CL data) to NC data, mapping the y-directional pick feed to the rotational angle of the rotary unit. Also, the post-processor has a novel function that elaborately adjusts feed rate values according to the curvature of each design so as not to chip the carved surface. The suitable feed rate values are generated by using a simple fuzzy reasoning method while checking edges and curvatures in a relief design. The post-processor allows the 3-axis NC machine tool with a rotary unit to easily carve an artistic relief design on a cylindrical wooden workpiece without an undesirable edge chipping. Experimental results show that wooden paint rollers with an artistic relief design can be successfully machined without any chipping.     

Simulation of normal machining of 3D free-form surface by an orthogonal 3-leg parallel machine tool with 5-DOF

A novel orthogonal 3-leg parallel machine tool (PMT) with 5 DOFs is designed for normal machining a 3D free-form surface s. A CAD variation geometry approach is adopted for pre-solving the extension/rotation of the linear/rotational actuators and the pose of this PMT. First, a simulation mechanism of this PMT is created by using the CAD variation geometry technique. Second, a s and a guiding plane of the tool path are constructed, the tool axis of the PMT is kept perpendicular to s, and then a simulation PMT is created. Third, in the light of the two kinds of prescribed tool paths, the extension/rotation of the linear/rotational actuators and the pose of the PMT are pre-solved automatically and visualized dynamically.     

An application-independent methodology of feature recognition with explicit representation of feature interaction

The existing feature-based design and feature recognition methods cannot fulfil the requirements of automated process planning. It is now recognized that satisfactory modelling of interactions between features is necessary for developing an automated process planning system. The selection of an optimum manufacturing process for a part needs to be considered at the conceptual design phase to incorporate the capabilities and constraints of the process in design. This paper describes a methodology of feature recognition that is independent of manufacturing process and explicitly generates geometric feature interactions in a part. The paper illustrates generation of feature sets for shape-forming processes, and describes a method to convert the process-independent features into machinable volumes and tool paths for material removal processes.