On-line measurement of surface roughness by laser light scattering

Abstract

On-line roughness measurement of a surface with one-dimensional manufacturing marks is difficult to implement. For example, a contact stylus-type inspection method often does not perform very well or fails without any prior knowledge of the mark distribution on the surface. In this paper, we propose an on-line surface roughness measurement method based on laser light scattering, which is very effective for roughness measurement of one-dimensional manufacturing surfaces. The surface roughness is obtained from the spatial distribution of the scattered light intensity. The measurement setup has a very simple configuration, which consists of a CCD sensor, a collimated diode laser and an expander. The orientation of the spatial distribution of the scattered light intensity from the surface, which depends on the surface orientation, is detected by the CCD sensor, and then the mark direction can be readily determined from image processing. After that the root-mean-square (RMS) height of the surface roughness is extracted by means of image processing of the scattered light distribution in the direction parallel to the manufacturing mark, rather than in the direction perpendicular to the mark which is often followed by other measurement probes. The experimental tests show that the non-contact method has great potential for on-line surface roughness measurement.

An Application of Sensor Array Processing in Characterizing One Dimensional Surface Roughness

“…In this part, we explain the prototype of surface roughness [15,17,18,19,20] study using a group of arrays of antennas and single transmitter of wave towards the plate with normal incidence, before discussing the implementation of high resolution angle of arrival techniques [1,2], let us describe the type of surface's irregularities we are focused on.…”

“…The roughness of surface is considered as random fluctuations [15,19] of protuberances that compose the material type of the surface, thus the roughness is random, and it can be described by two dimensional [19,20] or one dimensional function [17,18], we focus here on the last category, the statistical description of the randomness states that the height of The plate is placed in ( , ) xyplane, the lines of roughness are parallel to…”

“…The study of such surfaces is performed using profilometric [16] and optical techniques [8,16,17], the global shapes of protuberances are analyzed with optical interferomety using reflected laser beams [17]. In the other hand, the random roughness can be classified into one dimensional [17,18], two dimensional profile [19,20] or even three dimensional [20]. Verification of degree of roughness is an important step in many industrial sectors such as the verification of substrate of some electronic devices [21] and the quality of signal transmission over the sea surface which can be under calm and rough states [12].…”

Laser methods based on an analysis of scattered light for automated, in-process inspection of machined surfaces: A review

“…It was characterized by a low sensitivity to movements and vibrations of the measured elements. Lu and Tian used a similar approach [24]. This has been implemented in an optical measuring head of a similar design [23].…”

Simulation and Visual Control of Chip Size for Constant Surface Roughness

“…Kamguem et al [5] demonstrated that roughness parameters (R a , R t and R z ) can be estimated by using only image-extracted features. Lu and Tian [6] used light scattering techniques to realize the online prediction of machined surface roughness. Two non-optical methods were also developed.…”