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Traditional methods for measuring geometric errors in machine tools, including interferometry and Double Ball Bar (DBB), are known to be expensive and time-intensive. Consequently, a non-contact calibration system called the "Laser R-test" has been developed. This innovative system is designed to measure both position-independent geometric errors (PIGEs) and position-dependent geometric errors (PDGEs) efficiently. Since its development in 2000, this tool has been instrumental in analyzing eccentricity errors, angular position errors, and simultaneous trajectory errors. Through extensive research, it has been determined that the total error in a five-axis machine tool can be controlled to below 40 µm after compensating for eccentricity parameters and angular position errors. However, reducing this error to below ± 10 µm is challenging, primarily due to wobble errors in the orientation of the rotary axis without compensating. In this study, a new methodology based on Laser R-test and Rodrigues' rotation formula has been developed to establish a PIGE model of rotary axis. Based on the methodology, the 8 PIGEs can be analyzed by measuring 5 coordinate positions. The compensation of 8 PIGEs in the rotary axis is completed within 30 min using the inspection path. Compatibility with ISO-10791–6 standards for BK1, BK2, and BK4 path tests is confirmed, validating the compensation effects. A precision of below ± 10 µm is achieved, with inspection time reduced by over 50%. This system can complete multiple errors by simply using the different paths. This greatly reduces the setup time for future users, enhancing its commercial applicability. [ABSTRACT FROM AUTHOR]

The elastic deflection of the working areas of the active tool parts has a direct effect on the workpiece contact and thus on the component quality. Knowledge regarding the elastic behavior for typical process loads is of great importance for simulation of manufacturing processes as well as for the process layout, for example to maintain high predictive accuracy of the simulation methods or to reduce costs of the tool tryout process. With the aid of an experimental analysis, the deflection of the working areas for centric and eccentric loads is investigated using the example of a servo-screw press. The analyses focus on the evaluation of the machine's symmetry properties as well as the stroke position-dependent stiffness behavior. Based on the results of the experimental analysis, the quantification of the stiffness properties of the press slide for the process typical working space is carried out and boundary conditions for modeling of machine and process interactions are evaluated. [ABSTRACT FROM AUTHOR]

Single point incremental forming (SPIF) process has the potential to replace conventional sheet forming process in industrial applications. For this, its major defects, especially poor geometrical accuracy, should be overcome. This process is influenced by many factors such as step size, tool diameter, and friction coefficient. The optimum selection of these process parameters plays a significant role to ensure the quality of the product. This paper presents the optimization aspects of SPIF parameters for titanium denture plate. The optimization strategy is determined by numerical simulation based on Box-Behnken design of experiments and response surface methodology. The Multi-Objective Genetic Algorithm and the Global Optimum Determination by Linking and Interchanging Kindred Evaluators algorithm have been proposed for application to find the optimum solutions. Minimizing the sheet thickness, the final achieved depth and the maximum forming force were considered as objectives. For results evaluation, the denture plate was manufactured using SPIF with the optimum process parameters. The comparison of the final geometry with the target geometry was conducted using an optical measurement system. It is shown that the applied method provides a robust way for the selection of optimum parameters in SPIF. [ABSTRACT FROM AUTHOR]

This paper deals with an approach to identify geometrical deviations of flexible parts from optical measurements. Each step of the approach defines a specific issue which we try to respond to. The problem of measurement uncertainties is solved using an original filtering method, which permits to only consider a few number of points. These points are registered on a mesh of the CAD model of the constrained geometry. The shape resulting from deflection can be identified through the finite-element simulation of the part's deformation due to its own weight and the measuring set-up. Finally, geometrical deviations are obtained by subtracting geometrical deflections to measured geometrical deviations. The method is illustrated in an experimental test case. [ABSTRACT FROM AUTHOR]

This article introduces the concept of a measurement-aided welding cell (MAWC). It then focuses on developing the MAWC for body and chassis components in the automotive industry. Industry 4.0 requires flexibility and reconfigurability from manufacturing systems, which has been addressed by cellular manufacturing systems (CMS). Traditional automotive welding technology is not flexible enough to be used as a CMS. So, the core of automotive production does not meet the needs of next-generation manufacturing and Industry 4.0. For the first time, this demand has been answered-by the MAWC. The MAWC is based on two handling robots, a welding robot and an optical measurement system, all integrated into one welding cell. The measurement system controls guides and gives feedback to the handling and welding robots. This way, accurate welding is based on actual part-to-part adjustment, rather than hard mechanical tooling. The lack of hard mechanical tooling allows flexibility. Measurement-assisted assembly and machining is not new. However, it has not previously been applied to complex welding processes, because traditional measurement technologies have not been satisfactory. A newly developed system using multi-camera measurement technology meets the flexibility requirements. The technology required for a MAWC is reviewed and found to be in common use in the automotive industry. Three development projects are presented in which the main functions of a MAWC are successfully demonstrated. Two of these projects were done with BMW. A MAWC allows the manufacturing process to immediately swap to a different product on the same line, increasing the production line utilisation rate and making it possible to produce several low-volume products in one manufacturing system. So, the MAWC will not only yield benefits from its scalable capacity and global decentralization, but it will also open new business opportunities for manufacturing low-volume luxury car parts or post-production spare parts. [ABSTRACT FROM AUTHOR]

Temperature drifts, tool deterioration, unknown vibrations, as well as spindle play are major effects which decrease the achievable precision of CNC lathes and lead to shape deviations of the processed workpieces. Since currently no measurement system exists for precise, in situ, 3D shape monitoring, much effort is required to simulate and compensate these effects. In this article, we propose an optical measurement principle for first part quality manufacturing. The absolute shape, meaning the diameter and surface profile, of the workpiece is determined from its tangential velocity and the surface distance. In order to allow keyhole access, both measurands are determined simultaneously with a single sensor. Measurements inside a metal working lathe show that the standard uncertainty for the absolute shape measurement is below 1 μm. The measurement uncertainty is nearly independent of the lateral surface velocity and roughness. The in situ measurements are compared to measurements with a tactile coordinate measurement machine for reference. [ABSTRACT FROM AUTHOR]

Many car manufacturers are installing in-line car body measurement systems in order to achieve dimensional quality control of the whole production. The geometrical tolerances required by this product are narrowing increasingly; consequently, it is necessary to design these systems to calculate corrections and uncertainties as accurately as possible. This paper studies the error sources and analyzes their influence on measurement results by means of simulation and experimental tests during a nine-month study. The final goal of this work is to describe an optimization procedure for the accuracy improvement of the system. This is achieved mainly by applying a number of corrections designed to minimize the errors detected during the practical tests, and by means of algorithms to eliminate dispersions caused by a lack of stability in the positioning of the car body in the optical measurement system, or by temperature variations to reduce the final error. [ABSTRACT FROM AUTHOR]