LK Metrology
Mounted on a mobile workstation, LK Metrology's new Freedom index table being used to speed the inspection of an assembly using an LK portable measuring arm of the same name.

Ergonomic Rotary Index Table for Portable Arm CMM

March 2, 2023
Component inspection speed increases by up to 40%, with more efficiency and greater accuracy.

LK METROLOGY’s new Freedom Index Table increases the speed for component inspection using portable multi-axis measuring arms by up to 40%.  The CMM manufacturer says that not only is inspection more efficient, but also in some cases it is possible to use a smaller, less expensive arm to access all areas of a component.

Rotation may even avoid having to relocate the arm to enable sufficient access to the back of the part, which would lengthen the measuring cycle and could introduce inaccuracy. Additionally, the operator is not fatigued by repeatedly having to stretch to reach around the component, which can weigh up to 220 lbs (100 kg.)

Requiring no cables, the portable, manually operated, metrology grade index table is compatible with any make of portable measuring arm, not just LK's 6- and 7-axis Freedom arm range, which comprises 34 models. The 11.8-inch (300 mm) or optional 19.6-inch (500 mm) diameter table is quick to set up on a work surface, after which the operator secures the part to be inspected onto the surface with the aid of pre-drilled, threaded fixing holes or integral clamping magnets.

Similarly rapid is initial calibration of the start position by instructing the coordinate system to locate the table using InnovMetric’s PolyWorks|Inspector software. The speed of this procedure is a result of clever positioning of randomly placed, alphanumerically labelled, fiducial dimples machined into the top of the table and around its periphery. By probing three or more of these using the arm, the software recognizes the irregular pattern and automatically knows the orientation. It is then a simple matter to click the on-screen Freedom Index Table macro in the software to update the coordinate system then continue the part inspection.

To access the far side of the part, the table is rotated through 180 degrees (although any intermediate angle is possible), three or more different reference dimples are probed to update the software as to the new position, and measuring continues seamlessly. Both sets of inspection data are aligned automatically by the software. Measurement of geometrical features, evaluation of surfaces using advanced point cloud analysis, part-to-CAD comparison and full reporting in the PolyWorks 3D dimensional analysis and quality control software, all follow in the usual way.

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