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A New Approach to Spindle Radial Error Evaluation Using a Machine Vision System

Kavitha C., Ashok S. D.

Metrology and Measurement Systems

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2017

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Vol. 24, nr 1

201--219

EN

The spindle rotational accuracy is one of the important issues in a machine tool which affects the surface topography and dimensional accuracy of a workpiece. This paper presents a machine-vision-based approach to radial error measurement of a lathe spindle using a CMOS camera and a PC-based image processing system. In the present work, a precisely machined cylindrical master is mounted on the spindle as a datum surface and variations of its position are captured using the camera for evaluating runout of the spindle. The Circular Hough Transform (CHT) is used to detect variations of the centre position of the master cylinder during spindle rotation at subpixel level from a sequence of images. Radial error values of the spindle are evaluated using the Fourier series analysis of the centre position of the master cylinder calculated with the least squares curve fitting technique. The experiments have been carried out on a lathe at different operating speeds and the spindle radial error estimation results are presented. The proposed method provides a simpler approach to on-machine estimation of the spindle radial error in machine tools.

2

Analysis of the Pitch Circle Runout in Involute Splined Connections

Kroczak J., Dudziak M., Podolski T.

Machine Dynamics Research

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2011

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Vol. 35, No. 2

13-19

EN

The paper presents measuring methods of the pitch circle runout of involute splines and determination of the roundness deviation of the pitch circle from its runout results. The analysis of the influence of the runout on the tooth thickness, pitch and profile deviations is also shown. It was pointed out that the most characteristic roundness deviation is a pitch circle ovality of internal involute spline. This type of deviation often occurs for the parts with high hardness of material. The ovality is the reason for unequal contact depth of teeth and irregularity of interference or backlash.

3

Numerical simulation model for the determination of surface roughness in side milling as a function of feed and of the tool edges radii

Rojas H. G., Corral I. B., Calvet J. V.

Archives of Materials Science

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2007

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Vol. 28, nr 1-4

51-55

EN

A numerical model was developed in order to predict the surface roughness before machining the part. This model is based on the geometric tool-part intersection and allows defining the surface topography of the part as a function of the feed and of the radii of the tool edges. In this first study the problem of runout, i.e. differences between the radii of the different tool edges, is analyzed. The computational model allows determining the value of the average roughness (Ra) and the maximum roughness height (peak-to-valley) (Rt) along a line, in the direction of the feed, for a family of tools defined by an average radius of the edge and its standard deviation, assuming a normal behaviour. It was observed that the obtained values of average roughness Ra do not follow a normal distribution even though the values of the radii were randomly taken according to a normal law. A graphic was also obtained with the maximum and minimum value of average roughness Ra for each value of feed per tooth and per turn fz.