# Experimental Study of the Volumetric Error Effect on the Resulting Working Accuracy--Roundness
## 1 Introduction
From publication [20], it is obvious that it is necessary to ensure correct positioning of the temperature sensors in order to obtain valid data for correction of the measured data. Here, this information was used to verify machine stability and to correct the thermal expansion of machine components. Individual measuring devices can also be categorised according to the size of the machine tools. This classification is divided into small, medium and large CNC machine tools according to the size of the working space and the loading of the machine from the workpiece [21]. Not all machine tool sizes can be used with all devices and they should be selected according to the accuracy of the measuring equipment. Geometric accuracy is assessed according to ISO 230. These procedures are usually part of verification when deploying new methods of compensation of machine tools or models to predict machine accuracy [22]. It is based on the basic methods of compensating for the geometric errors of the tillage machines summarised in publication [23]. Another standard that can be used to verify the accuracy of a machine is the tests based on ISO 230-4 that mostly  
The working accuracy of a machine can be verified using ISO 10791-7 of the standardised component [27]. This workpiece is specified to verify the production accuracy of three-axis kinematics with the option of assessing several dimensional and shape deviations. Publications [22] and [28] describe the effect of machine load on the position of the rotary axis, as well as the resulting orientation errors. When assessing the geometric errors of the machine, it is necessary to consider the machining forces and heat dissipation in the machine. This publication is focused on describing the dependence between the volumetric accuracy of the machine and the resulting working accuracy, assessed on the error of workpiece roundness under finishing conditions of machining. The dependence between volumetric accuracy and roundness error is described in publication [29], according to ISO 230-4. The presented experiment focuses on the verification of the correlation between the volumetric accuracy of machines and production accuracy. In this case, geometric accuracy is represented by volumetric accuracy. The measurements of volumetric accuracy are based on the indirect method, using the self-guiding laser interferometer LaserTRACER. This method is described, for example, in [3]. In order to assess the influence of volumetric accuracy on the resulting working accuracy, it is important to observe constant ambient conditions due to the repeatability of the production of test workpieces. The negative effect of temperature on the change in volumetric accuracy is described in [30]. Production accuracy is represented in a test workpiece designed to verify roundness error. This is then verified by the Talyrond 5955 measuring device. The roundness results of the workpiece are then compared to those obtained with the circular interpolation test, according to ISO 230-4. The measuring device used is the Ballbar QC20-w.