The need for higher accuracies on machine components is on the rise. This is especially apparent in the manufacturing of large aerospace components where current designs are pushing the limits of the machine tool capabilities. One way to make large parts with tight tolerances is to use a high quality machine in a temperature controlled environment. But, as machine tools increase in size the thermal environment cannot economically be controlled to meet tight tolerances. A technique using fiducials has been demonstrated to allow a more common production machine to achieve similar results. This technique allows flexibility in machining strategies that was not otherwise possible. The increased flexibility comes from two main areas: eliminating the need for tight temperature control and the ability to reset coordinate systems as machining progresses. The methodology presented allows the user to choose the number and position of fiducials implemented in the algorithm. For example, with large monolithic aerospace components, one of the major difficulties in achieving part tolerance derives from the size of the machine tool that, until now, was directly related to the size of the part. The potential now exists for an entirely new machine configuration where a large part with fiducials is fed through a small work volume. The fiducials allow the machine reference to be reset resulting in both local and global accuracy with a work volume smaller than the part. Additionally, there are other possible applications for this technology which include: (1) real time, on machine calibration of changing thermal and squareness errors using a master calibration part and (2) a diagnostic and correction tool for evaluation and correction of machine condition after an accidental crash, upon loss of power during cutting, and/or upon rebuild of any part of the machine tool. These applications have the potential to significantly impact quality in both low volume and high volume production environments.
Improving the accuracy of large scale monolithic parts using fiducials
Erhöhung der Genauigkeit großer monolithischer Teile mit Hilfe von Bezugswerten
2005
4 Seiten, 6 Bilder, 6 Tabellen, 9 Quellen
Aufsatz (Konferenz)
Englisch