Development of a parametric model and virtual machine to estimate task specific measurement uncertainty for a five-axis multi-sensor coordinate measuring machine

2011 ◽  
Vol 35 (3) ◽  
pp. 431-439 ◽  
Author(s):  
P. Ramu ◽  
J.A. Yagüe ◽  
R.J. Hocken ◽  
J. Miller
Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.


2014 ◽  
Vol 598 ◽  
pp. 189-193
Author(s):  
Hui Zhao ◽  
Yu Jun Cai ◽  
Guo He Li

In this paper, a very detailed process analysis for UAV integral impeller was made. According to the specific processing requirements, the appropriate CNC machine, blank and cutting tools have been choosing. In the rough machining process, various machining strategies have been used for comparing and analyzing, finally a more efficient roughing method with the accurate machining parameters will be obtained. At the same time the machining method have been improved and the processing parameters also have been determined in the semi-finishing process. Through the simulation processing in VERICUT, the possibility of the existence of interference which is usually occurred in the actual processing can be ruled out and the program optimization will be finished in the meantime. Finally, using intelligent three-coordinate measuring machine the consequence will be verified and inspected in the actual machining process.


Author(s):  
M Terrier ◽  
M Giménez ◽  
J-Y Hascoët

Ten years ago a new kind of machine tool was presented in Chicago, based on parallel kinematics architectures. Since then, many of these parallel kinematics machines (PKMs) have been developed around the world. Their main interest lies in their high dynamic characteristics, which could help in going faster in high-speed milling. In order to develop high-speed milling on PKM tools and to highlight their potentialities, the French laboratory IRCCyN is now equipped with the VERNE. This PKM tool has been developed by the Spanish company Fatronik. However, the high-speed milling production process is a complex task, in which a great number of parameters influence the final precision of the part and the productivity of the machine. For example, the NC (numerical control) and computer-aided manufacturing (CAM) parameters (feed forward, milling strategies, etc.), the piece geometry, the machine structure, the tool, etc., have a direct consequence on the final part. Hence, a method has been developed in order to check the capability of the machine (either serial or parallel) in milling, which relies on two approaches. The first one is an experimental approach (either using a coordinate measuring machine or acquiring the output axis encoders), while the second one is a simulated approach. After introducing the kinematics of the VERNE, the experimental approach performed so far will be presented.


2019 ◽  
Vol 10 (1) ◽  
pp. 37 ◽  
Author(s):  
Michaela Kritikos ◽  
Lissette Concepción Maure ◽  
Alfredo Alejandro Leyva Céspedes ◽  
Daynier Rolando Delgado Sobrino ◽  
Róbert Hrušecký

This paper addresses the uncertainty analysis in the case of a coordinate measuring machine. The main goal was analyzing, quantifying, and drawing conclusions on the influence of key factors and their interactions on the measurements’ uncertainty of the variable’s parallelism, angularity, roundness, diameter, and distance. In order to achieve this goal, a Random Factorial Design of Experiments was designed and implemented. It focused on the factors Stylus diameter, Step width, and Speed using three random levels each. For the solution of the experiment, an analysis of variance was used. The study was carried out on the coordinate measuring machine (CMM) ZEISS CenterMax. It was concluded that the interaction effects among Stylus diameter, Step width, and Speed were active at a confidence level of 95%. Besides, it was possible to estimate random factors‘ variance and their contribution to the total variation. Among the main effects, the Stylus diameter showed to be the one with the biggest influence. The paper also quantifies the influence in the measurement uncertainty, where the highest value of standard uncertainty belonged to the Stylus diameter in the evaluation of the variable’s angularity and diameter. Besides, the Speed factor was proved to have the biggest influence on the roundness’ measurement and evaluation.


Author(s):  
Haitao Zhang ◽  
Shugui Liu ◽  
Xinghua Li

REVO five-axis system, designed for the orthogonal coordinate measuring machines, must be reconfigured for the application in the non-orthogonal coordinate measuring machines. First, in this article, error sources of the system and components of measurement data are analyzed; then, scale values of coordinate measuring machine axes, which are essential to derive the coordinates of measured points in non-orthogonal coordinate measuring machine, are separated out. Besides, the mathematical model of REVO is established based on the quasi-rigid body theory, from which the measurement results can be evaluated by data derived instead of that returned by the system. The effectiveness of both separation of scale values and mathematical model of REVO is proved by experiments and practice. The research of this article is of great significance to the application of REVO five-axis system in the non-orthogonal coordinate measuring machine.


Author(s):  
Yohan Kondo ◽  
Kazuyuki Sasajima ◽  
Sonko Osawa ◽  
Osamu Sato ◽  
Masaharu Komori

The pitch accuracy of a gear is graded on the order of 0.1 μm in ISO 1328-1; therefore, it is necessary for gear measuring instruments (GMIs) to be able to measure gears with the required high accuracy. GMIs are evaluated by measuring a calibrated gear or a gearlike artifact. It is, however, difficult to obtain a measurement uncertainty of less than 0.1 μm. The reason for this difficulty is that a gear artifact has a form error and surface roughness, and that the measurement position on the gear face differs slightly from the calibrated position. In view of this situation, we propose a novel multiball artifact (MBA), which is composed of equally spaced pitch balls, a centering ball, and a datum plane. The pitch balls are assumed to act as gear teeth by calibrating the angular pitch between the centers of each pitch ball. The centering ball and the datum plane are used to set a reference axis of the virtual gear. We manufactured an MBA with the pitch balls arranged on a curvic coupling. The angular pitch deviation between the centers of each pitch ball was calibrated using a coordinate measuring machine (CMM) and adopting the multiple-orientation technique. A master gear was also calibrated for comparison. The measurement uncertainty for the cumulative angular pitch deviation was 0.45 arc sec for the MBA and 1.58 arc sec for the master gear. The MBA could be calibrated with small uncertainty compared with the master gear. After the calibration, a virtual gear of the MBA was built using the calibration value. The virtual gear was measured using the gear-measuring software on the CMM. The measurement value was equal within the range of uncertainty of calibration value. It is verified that the superiority of the MBA to the gear artifact is due to the following reasons: (1) The balls can be manufactured with an accuracy of several tens of nanometers. (2) The calibrated result for the MBA is almost independent of a probe-positioning error because the centers of each pitch ball can be measured at multiple points. (3) In setting the reference axis, the gear artifact generally uses a datum cylinder, in contrast, the MBA uses more accurate ball.


Author(s):  
Giovanni Moroni ◽  
Stefano Petro`

Uncertainty is a key concept in any environment which involves measurements to ensure process quality: a trade-off has to be found between measurement costs, which increase as uncertainty lowers, and costs related to measurement errors. In mechanics, geometrical conformance is a common requirement. Two similar standards series deal with the problem of uncertainty in geometrical error estimate: ASME B89.7.3 and ISO 14253. Geometrical inspection is often performed by means of a “Coordinate Measuring Machine” (CMM). For a CMM, a trade off between measurement and errors costs may be found by optimizing the sampling strategy. In this work a cost function will be proposed as support for finding a trade-off between measurement uncertainty and costs. This function may be optimized by means of an heuristic algorithm. The method will involve repeated measurements of calibrated parts to evaluate uncertainty (like in ISO/TS 15330-3). A case study will be proposed.


Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6638
Author(s):  
Michiel Vlaeyen ◽  
Han Haitjema ◽  
Wim Dewulf

Digital twins of measurement systems are used to estimate their measurement uncertainty. In the past, virtual coordinate measuring machines have been extensively researched. Research on digital twins of optical systems is still lacking due to the high number of error contributors. A method to describe a digital twin of an optical measurement system is presented in this article. The discussed optical system is a laser line scanner mounted on a coordinate measuring machine. Each component of the measurement system is mathematically described. The coordinate measuring machine focuses on the hardware errors and the laser line scanner determines the measurement error based on the scan depth, in‑plane angle and out‑of‑plane angle. The digital twin assumes stable measurement conditions and uniform surface characteristics. Based on the Monte Carlo principle, virtual measurements can be used to determine the measurement uncertainty. This is demonstrated by validating the digital twin on a set of calibrated ring gauges. Two validation tests are performed: the first verifies the virtual uncertainty estimation by comparison with experimental data. The second validates the measured diameter of different ring gauges by comparing the estimated confidence interval with the calibrated diameter.


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