Fang-Jung Shiou

AUTOMATED OPTICAL INSPECTION SYSTEM FOR THE RUNOUT TOLERANCE OF CIRCULAR SAW BLADES

Circular saw blades are fundamental cutting tools applied to cut off materials. Inspection of finished products of circular saw blades is important in order to ensure their manufacturing quality and sawing performance. Traditionally, a contact inspection method is adopted to measure the runout amounts of circular saw blades. In order to improve the quality of the runout inspection, a non-contact inspection method based on machine vision is required. In this paper, an automated optical inspection (AOI) system was developed exclusively for inspecting the runout tolerance of circular saw blades. Based on the integration of motion control and image processing techniques, calibration and automated inspection processes for the developed AOI system were then established. Experiments to inspect circular saw blade samples were also conducted in order to test the feasibility and reliability of the developed AOI system. From the experimental results, the developed AOI system, in combination with the automated inspection process, could achieve sufficient repeatability and was verified to be able to inspect the runout tolerance of certain circular saw blades.

Design analysis and applications of a 3D laser ball bar for accuracy calibration of multiaxis machines

Abstract Conventional techniques for measuring the volumetric errors of Cartesian coordinate machine tools are time consuming using a laser interferometer or step gauges. For multiaxis machines, where the spindle can swing, volumetric error calibration is even more difficult. In this study, a novel 3D laser ball bar (3D-LBB) has been developed for the easy setup and rapid measurement of the tool position relative to the worktable at any working point of multiaxis machines. The instrument makes use of one laser ball bar and two rotary laser encoders to detect the target path in the spherical coordinate system. The design of the instrument is discussed, and the error attributes are analyzed to enhance the instruments accuracy. Applications to the volumetric error measurement of a robot and two types of machine tools have demonstrated the high-precision capability of this 3D laser ball bar.

Design of a Meso-scale 3-axis Milling with Nanometer Accuracy

The objective of this research was to develop a meso-scale 3-axis milling machine with a nanometer resolution. The main elements of the Z-axis design of the meso-scale 3-axis milling machine are a pagoda structure, a high speed air bearing spindle, two HR8 ultrasonic motors, a laser diffraction grating interferometer system (LDGI) and a coaxial counter-balance system for the spindle. The optimal geometrical dimensions of the pagoda structure have been determined by ANSYS software. According to the simulation results, the maximum static deformation along the z-axis of the pagoda was about 5.05 nm. Vibration amplitude tests of the Z-axis of a micro-milling machine driven by either an ultrasonic motor or two ultrasonic motors have also been caried out to provide better design information for the Z-axis. The meso-scale 3-axis milling machine is equipped with an X-Y coplanar positioning stage with nanometer resolution, including the low-cost components and two ultrasonic motors, in order to reduce both the complexity and errors resulting from the combination of a long-stroke stage and short-travel stage. The coplanar stage developed by Nation Taiwan University was integrated with two laser diffraction grating interferometer systems as displacement feedback sensors, so that a two-axis closed-loop control was possible. The positioning accuracy of the coplanar stage was about 200 nm after error compensation, base on the test results. A circular positioning test with the radius of 100 μm using the stage developed was tested, and the overall roundness error was about 4.01 μm based on the preliminary test results.