DETERMINATION OF OPERATOR’S IMPACT ON THE MEASUREMENT DONE USING COORDINATE TECHNIQUE

Coordinate measuring arms (CMAs) are devices which more and more often replace conventional coordinate measuring machines because of their undoubted advantages, such as mobility, the opportunity to increase the measuring volume, the opportunity to connect the optical probe, and above all, good price-quality ratio. Because these devices are handheld and redundant, what has the greatest impact on the measurement result accuracy are the operator, the machine kinematics and its ability to obtain repeatable measurement results; despite the fact that one point can be obtained from an infinite number of shoulders’ positions. In this paper it was determined by using R&R method how significant are the impacts of both the operator and the measuring device on the accuracy of measurements done with CMA, both with rigid switch probe and optical probe

Measurements of Tensile Strength and Elongation of 3D Printed Polylactide Solids Produced with Different Temperatures of Extruder Using Coordinate Measuring Technique and Finite Element Method

In order to determine the largest and smallest deformations during 3D printing, measurements were made for pure polylactide (PLA) using a coordinate measuring technique using a measuring arm. The additive manufacturing process was carried out using four nozzle temperatures: 190℃, 200℃, 210℃ and 220℃. The model was properly selected to check the cylindricity, angles of inclination and dimensional deviations from the nominal value of the cuboid. FEM analysis was used to confirm the obtained results. The cylindricity and shape tolerances were shown to be the best at 190℃. The smallest deviations from the angle of 90 ° have solids made at 200 ℃ and 220 ℃. In the case of dimensional tolerances of the centers of the holes relative to each other, the best deviations were obtained for the temperature of 190 ℃ and 220 ℃. The highest stress values during uniaxial stretching using FEM analysis were obtained for samples made with nozzle temperatures of 200°C and 210°C, which are about 31 MPa. For the temperature of 190°C and 220°C, the deviations are the closest to the reference model and are equal to about 30 MPa. In the case of the FEM analysis for single-point bending, the element made at 190°C had a maximum deformation of 0.203 mm, which was the same for the reference model. The largest deviation is noticeable for the printing temperature of 200°C and is 0.211 mm

ESTIMATION OF MEASUREMENT UNCERTAINTY WITH THE USE OF UNCERTAINTY DATABASE CALCULATED FOR OPTICAL COORDINATE MEASUREMENTS OF BASIC GEOMETRY ELEMENTS

The paper presents a method for estimating the uncertainty of optical coordinate measurement based on the use of information about the geometry and the size of measured object as well as information about the measurement system, i.e. maximum permissible error (MPE) of the machine, selection of a sensor, and also the required measurement accuracy, the number of operators, measurement strategy and external conditions contained in the developed uncertainty database. Estimation of uncertainty is done with the use of uncertainties of measurements of basic geometry elements determined by methods available in the Laboratory of Coordinate Metrology at Cracow University of Technology (LCM CUT) (multi-position, comparative and developed in the LCM CUT method dedicated for non-contact measurements) and then with the use of them to determine the uncertainty of a given measured object. Research presented in this paper are aimed at developing a complete database containing all information needed to estimate the measurement uncertainty of various objects, even of a very complex geometry based on previously performed measurements

VALIDATION OF THE METROLOGICAL MODEL OF COORDINATE MEASURING ARM USING MULTIFEATURE CHECK

The article presents the validation research scheme of metrological model of coordinate measuring arm (CMA) using multifeature check. The scheme shows the comparison of the calibration results of the check using selected coordinate methods and criteria of validation. The comparison shows the insignificance of differences between the obtained results of both: metrological model of CMA and multi-position method. It evidently proves the correctness of the development of metrological model of CMA. The use of appropriate quality multifeature check also had a significant impact on the results. This check is now the most accurate measurement length check and its use for this validation process was the most suitable

Accuracy Verification of Surface Models of Architectural Objects from the iPad LiDAR in the Context of Photogrammetry Methods

The creation of accurate three-dimensional models has been radically simplified in recent years by developing photogrammetric methods. However, the photogrammetric procedure requires complex data processing and does not provide an immediate 3D model, so its use during field (in situ) surveys is infeasible. This paper presents the mapping of fragments of built structures at different scales (finest detail, garden sculpture, architectural interior, building facade) by using a LiDAR sensor from the Apple iPad Pro mobile device. The resulting iPad LiDAR and photogrammetric models were compared with reference models derived from laser scanning and point measurements. For small objects with complex geometries acquired by iPad LiDAR, up to 50% of points were unaligned with the reference models, which is much more than for photogrammetric models. This was primarily due to much less frequent sampling and, consequently, a sparser grid. This simplification of object surfaces is highly beneficial in the case of walls and building facades as it smooths out their surfaces. The application potential of the IPad LiDAR Pro is severely constrained by its range cap being 5 m, which greatly limits the size of objects that can be recorded, and excludes most buildings

How to Adapt Mongolian Yurt to the Modern Requirements and European Climate—Airtightness versus CO₂ Concentration?

There are currently trends in the world to transfer and adapt traditional solutions to contemporary needs. This applies, inter alia, to mobile shelters used by nomadic peoples. The article is devoted to the research on the quality of internal air in the yurt and the possibilities of its adaptation to high contemporary quality and environmental requirements, while maintaining its characteristic sustainable values. The tested traditional Mongolian yurt was moved from the dry and cold climate of the Asian steppe to the temperate climate of Central Europe and has been significantly modified. The outer shell materials have been changed, replacing natural materials with modern tight insulating foils. The wood-fired stove has been replaced with an electric heater and the roof opening has been firmly closed. All of these modifications resulted in far-reaching changes in the quality of the internal environment in the yurt. The conducted measurements and simulations of CO2 concentration in the modified yurt proved that the efficiency of ventilation system is not sufficient and that the air quality is very poor (even for a single user). In the case of a larger number of users, the concentration of CO2 has already reached a level that was dangerous to health. The simplest method of improving the air quality in the yurt is its careful unsealing to the required level. Striving for a low energy demand, however, would require a completely different approach (for example, in the form of forced ventilation with a heat recovery unit, ultimately powered with a PV array). Such a solution is very different from the traditional yurt model but is close to modern expectations and environmental requirements