Adequacy of Technical and Commercial Alternatives Applied to Machine Tool Verification Using Laser Tracker

Abstract

Besides presenting a volumetric verification technique that allows characterization of the different geometric errors of a machine tool (MT) depending on its kinematic chain and geometry through a kinematic model, this paper investigates the influence of measurement tools and techniques available on the final accuracy of the MT. Volumetric verification based on a laser tracker (LT) relates the coordinates of the tool with the coordinates of the LT, including it into the kinematic model. Using a non-lineal optimization process, approximation functions that characterize the joint influence of MT geometric errors are obtained. However, measurement data will be affected by previous compensation of the MT, the accuracy of the measurement system, LT measurement technology, the type of retroreflector used, and techniques used to improve data accuracy, among other sources of errors. This paper studies the adequacy of different commercial alternatives such as: retroreflectors, LTs from different manufacturers, etc., that can be applied in MT verification using a long-range MT. As the accuracy is strongly affected by the uncertainty of its angular encoders, the multilateration technique tries to improve data accuracy using only LT radial information. Nonetheless, a new bundle adjustment which uses radial and angular information is presented in current metrology software. This paper studies both techniques and analyzes their adequacy for MT verification too.

Research of omnidirectional measurement method to detect the errors of multi‐axis numerical control machine tool based on laser tracker

“…The omnidirectional measurement algorithm includes selfcalibration of base stations and the determination of measuring points. Then geometric errors of machine tool are separated by error separation algorithm [12,15].…”

Analysis of the initial thermal stabilization and air turbulences effects on Laser Tracker measurements

“…Laser Tracker systems, as portable coordinate measuring machines, have become a notably important metrological tool for industries that must manage large scale components, such as aerospace, wind power, automotive or even machine tool manufacture [1][2][3][4][5][6]. One common feature of all these sectors is the need to make precise measurements on the shop floor.…”

“…Therefore, the measurement uncertainty of these systems is dependent on the laser system itself, which measures the distance to target (ρ), and the rotary encoders, which provide the angular position (Ɵ, φ). The angular encoders are widely recognized as one of the main sources of uncertainty [7,8] and the reason of the development of the multilateration techniques [6]. Nevertheless, in the continual effort to attain higher accuracies, some improvements related to distance-measuring uncertainty are still possible.…”

“…There are three major manufacturers of Laser Trackers: Leica Geosystems, Faro Inc. and API. Each manufacturer has its own design and system characteristics [6]. The University of Zaragoza has an API Tracker3 LTS-3000 and a Leica Geosystems LTD600.…”

Measurement Parameters Optimized for Sequential Multilateration in Calibrating a Machine Tool with a DOE Method

“…Several techniques and appliances are used to estimate this error in the whole discretized working volume: telescopic ball-bar [10,11], 3D probe-ball [12], R-test [13], laser technology [14][15][16], etc. Laser techniques are the most widespread appliances in the research field and the tracking laser is the most reliable instrument used [15,16].…”