Yoshio Mizugaki

Fractal Path Generation for a Metal-Mold Polishing Robot System and Its Evaluation by the Operability

This paper suggests a new method of Fractal path generation in a robot system of polishing metal molds It is conducted through the generation of a planer Peano curve in the X-Y domain and its orthogonal projection onto the free-form surface of a workpiece The orientation of the end-effector along the path is set perpendicular to the surface By calculating the sum of operability of the robotic linkage along the path the path can be evaluated from the ease of the rebots’ motion The experiments inclusive of the polishing force control are illustrated and a brief conclusion made.

Development of Metal-Mold Polishing Robot System with Contact Pressure Control Using CAD/CAM Data

Abstract This paper presents a new metal-mold polishing robot system which consists of a 6 D.O.F. industrial robot, a compliant polishing end-effector and a robot controller communicating with a CAD/CAM system. The end-effector consists of an air grinder, a spring coil and a sliding guide driven by a stepping motor. The tool path is composed by both a nominal path on the surface of the mold model and an offset relating to the contact pressure based on the end-effectors elasticity. The experimental results support the efficiency of the contact pressure control path as to preventing over-polishing at an edge.

Theoretical Estimation of Machined Surface Profile Based on Cutting Edge Movement and Tool Orientation in Ball-nosed End Milling

Abstract This paper presents the theoretical estimation method of machined surface profile without actual machining in ball-nosed end miling. The fundamental simultaneous equations of identifying the cusp height at any point of a workpiece in the simulated surface have been successfully derived from the geometric relationship between the cutting edge movement and the normal line at the point. By the numerical calculation, the machined surface profile can be estimated and illustrated graphically. It was found that the maximum and minimum cusp heights exist in a narrow range of tool orientation less than 3 degrees near the normal direction.

Geometric Generating Mechanism of Machined Surface by Ball-nosed End Milling

Abstract This paper presents a new geometric estimation method of machined surface by ball-nosed end milling in sphere contouring. Firstly the geometric relationship between a cutting edge and a normal vector of the sphere has been formulated. Through the equation analysis, multi-crossing of them up to three times and the zigzag movement of the cutting edge have been found newly. Also the interference by a major flank was found too. Secondly a numerical calculation solver was developed by Newton-Raphson method. Thirdly the graphical display was realized by a CAD system. Through the observation of machined surfaces, the interference area was confirmed.

Optimal tool selection based on genetic algorithm in a geometric cutting simulation

Abstract This paper presents new methods of offset surface generation and milling tool selection. Firstly the calculation of a workpieces area cut by a tool is done by detecting contact points between the tool and the workpiece in a lattice space model. Secondly the tool selection is made by Genetic Algorithm to minimize the total machining time and the uncut area. A tool set is coded as a binary bit string. It is assumed the tools would be used in the descent order of radius and cut their corresponding area as entirely as possible. Simulations and conclusions are briefly described.

Fractal path application in a metal mold polishing robot system

This paper describes an industrial application of fractal paths in a metal mold polishing robot system. This is characterized by the fact that a fractal curve is suitable to cover a free-form surface uniformly at any complexity due to its plane-filling and self-similar characteristics. Path generation is discussed in terms of the parameter domain of a spline surface and its orthogonal projection. The robot system consists of an articulated industrial robot of 6 d.o.f. and a polishing end-effector with the contact force control. The polishing experiments as to the contact force control and fractal paths are presented.<<ETX>>

Contouring electrical discharge machining with on-machine measuring and dressing of a cylindrical graphite electrode

This paper presents a new approach of contouring electric discharge machining (EDM) by means of the on-machine measuring and dressing of a ball-nosed cylindrical graphite electrode. The on-machine measuring is done in order to detect electrode wear by a laser range sensor. The on-machine dressing is carried out by turning the electrode with a disk shaped cutting tool fixed in the EDM machine. Machining experiments by contouring EDM have been performed and their results are compared with those by diesinking EDM in terms of the total machining time, electrode cost and machining error. Their results support the efficiency and validity of contouring EDM.

Precision Turning by Means of a Simplified Predictive Function of Machining Error

Abstract This study deals with a compensative system for machining errors in turnings by adopting a simplified predictive function and modifying previous NC commands. The predictive function is represented in the form of an exponential function as an experimental expression and installed into an auto NC programming tool as a database. A NC command is modified by varying its depth of cut from which the motion resolution of a lathe is subtracted everywhere the predicted machining error exceeds the motion resolution. The experimental results support the efficiency of the compensative system proposed in some intermittent metal cutting.

Geometric simulation of ball end milling and application for the precise machining

This paper clarifies the geometric influence of tool orientation on the thickness of undeformed chip in ball end milling because the influence of tool orientations on machining accuracy has never been investigated. Not only the shape of undeformed chip but also its thickness varies according to the tool orientations. The authors developed the experimental method for measuring the machining error on inclined surface in any direction and the simulation method of hemi-ellipsoid cutting. The experimental and simulated results support the influence of tool orientations. Through the experimental results and the simulation, the relationship between the tool orientation and the machining error has been clarified. The influence of tool orientation and tool path on the machining error has been discussed too.

Research about Elastic Mechanism of Error Generation in Ball End Milling based in Geometric Analysis

This paper clarifies the elastic mechanism of error generation in ball end milling. At first geometric influence of the tool orientation on the thickness of undeformed chip in the ball end milling is analized precisely. Not only the shape of undeformed chip but also its thickness varies according to the tool orientations. So the authors have established a model of the elastic deformation of the ball end mill caused by the cutting force. As the verification of this model, the authors developed the experimental method for measuring the machining error on inclined surface in any direction and the cutting force is measured in same time. The cutting force on these experiments and the simulated results support the influence of tool orientations. Through the experimental results, the relationship between the tool orientation and the machining error has been clarified. The influence of tool orientation on the machining error has been discussed too. Finally the simple equation has been proposed that decribes the relationship between the geometric value of the cutting area and the elastic deformation of the ball end mill.