# Measuring Procedures for Evaluating the Surface Roughness of Machined Parts
## 1 Introduction
This issue is very extensive, so for this article, we will deal with quantities--the arithmetic mean deviation of the assessed roughness profile and the quality of the surface of the components is relevant for the assessment. Author [PERSON] [1] provides a definition for the term \"surface metrology\", which aims to optimize the functions of the production process and its tools to support effective management. This optimization directly affects the quality of products, making surface metrology crucial in predicting outcomes within the production process. In the paper by [PERSON] [2], a comprehensive review of various methods for measuring surface texture is presented, accompanied by a classification scheme for these methods. [PERSON]'s work [3] focuses on the measurement and uncertainty analysis of surface roughness, specifically addressing the influence of cutting conditions during turning. The study investigates the arithmetic mean deviation of surface roughness (_Ra_) and Material Removal Rate (MRR). In the study conducted by [PERSON] [4], a practical methodology for measuring roughness when turning with tool inserts featuring variable tool faces is introduced. The research emphasizes the importance of adopting a unified roughness measurement methodology to compare the capability of different tool inserts. The study evaluates measured data such as _Ra_, _Rq_, _Rz_, _Rt_, and _Rp_. [PERSON] [5] conducts a detailed experimental study to assess the individual and combined effects of scanning speed and spacing on surface roughness parameters. The study focuses on a reference specimen, selecting profile parameters (_Ra_, _Rq_, and _Rz_) and surface parameters (_Sa_, _Sq_, and _Sz_) as response variables. The findings highlight the significant impact of scanning speed on _Ra_, _Rz_, _Sq_, and _Sz_ measurements, while spacing affects all profile and surface measurements. Surface roughness measurements are primarily performed using stylus roughness meters for machined surfaces. However, atomic force microscopes (AFM) are also utilized for surface roughness evaluation, including the assessment of uncertainty for surface roughness parameter \(Ra\)[6]. Surface topography measurements are becoming more and more popular and complement the 2D analysis of surface texture [7; 8; 9; 10]. The selection of the measurement area is not yet included in the standards, and the size of this area affects the values of the determined parameters. The article [11] presents the results of research on determining the measurement area based on the smooth-rough crossover scale (SCR) and mean profile element spacing (\(RSm\)) parameters. Other works also address the measurement of the surface roughness of components [12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24]. The aim of the article is to determine the uncertainty estimate of the measurement of arithmetic mean deviation of surface roughness \(Ra\) for the used measuring device of surface roughness quantities and to verify the measurement methodology from the point of view of setting the measurement parameters. The problem is that the manufacturer usually does not specify the maximum permissible error of the measuring device, and even for surface roughness standards (calibration etalon), the maximum error of determining its nominal value is not declared either, and therefore, values must be determined by calibration. A fundamental problem in this measurement is the appropriate measurement conditions, and the measurement and evaluation of surface roughness values are characterized by the fact that it is sensitive to the correct selection of measurement conditions. Although there are recommendations that are in some available standards, they may not always take into account the actual measurement conditions, and it is advisable to verify them for specific conditions.