Papers by Keyword: Alignment Errors

Abstract: The main goal of the kinematic feed chains used on numerically controlled machine tools is to ensure the relative position between the manufactured part and the cutting tool tip with a high accuracy. Therefore, the positioning precision is a major performance criterion for CNC machine tools. The guidance system of the machine table, together with the actuation system and the closed-loop control system, represents a key factor in manufacturing high precision machine tools. Mounting and alignment errors of guideways, both in vertical and horizontal directions, directly affect the table positioning precision and implicitly, the manufacturing precision of the machine tool. Guideways misalignment also generates stresses, plays and excessive run-out. The present paper contains a method of experimental analysis regarding the influence of guideways alignment errors on the positioning precision of the kinematic feed chains, which takes into account the alignment of the two guide rails, both in vertical and horizontal plans. The feed axis used in the experimental setup is closed-loop controlled, making use of an indirect position measurement system.

Abstract: The nose roundness is one of the most important indexes of lapping quality of rounded diamond cutting tools. Due to its special characters and requirements, a new measuring method was proposed based on atomic force microscope (AFM) and precision-revolution spindle. However, in the measurement the alignment errors of tools with the spindle axis have great influence on the measuring result. By a carefully deducting, the relations between the deviation and the alignment errors were presented. The deviation increases with the eccentric linearly, and has the same value with the eccentric. But it varies with θ dramatically and forms a parabola curve when the deflection angle is negative, otherwise, varies with θ gently and forms a flat Gaussian curve.

Abstract: This paper discuses the development of the optical sensor due to detect the micro crack and measure the surface property of the contact surface in the equipment. To measure the surface property is an index for detecting no uniformity contact and / or micro crack on the contact surface. So, there is demand of the development of the sensor to measure the surface property in using equipment. This sensor has two optical systems, called stylus and skid, to reduce the influence of vibrations on the measurement result. The stylus measures the surface property with the vibration, and the skid measures only the displacement between the sensor and the objective surface at the same place as the stylus, i.e. the vibration. Therefore, the stylus signal minus skid signal shows the surface property. In this research, the proposal of the principle of this system, the methods of the development and the evaluation of the stylus system of the sensor and the development of prototype sensor is described.

Abstract: The sensitivity of various combinations of optics to alignment errors is investigated. A large number of tests with varying specimen displacements and incident beam misalignments are performed for both line and point focus residual stress optics combinations. This investigation includes experiments with mixed combinations of typical “focusing beam optics” and “parallel beam optics”. It is verified if the peak positions are either sensitive to height errors like for the focusing beam geometry or insensitive like for the parallel beam geometry. The peak position sensitivity is classified for all combinations of incident beam and diffracted beam optics modules.