Okuma 5-axis Auto Tuning simplifies and speeds up elimination of machine inaccuracies

The 5-Axis Auto Tuning System option for Okuma's horizontal-spindle MU-H and vertical-spindle MU-V series of 5-axis machining centres performs measurements and compensation automatically, reducing adjustment time from five hours to 10 minutes. The system is not only faster, but also, unlike manual procedures, not susceptible to human error. A 5-axis machine has three linear axes (X, Y and Z) and two rotational axes (A and C) for machining complex parts. The more axes a machine has, the greater the potential for geometric errors, which can change over time due, for example, to movement of the floor surface. Errors include displacement of the centre position of the rotary axis, tilt of the rotary axis with respect to the orthogonal axes and thermal deformation, changes in the installation environment over time. Errors can cause steps when machining a slope, shape defects when profile-milling a curve and other problems. Okuma's 5-Axis Auto Tuning System measures geometric errors using a touch probe and datum sphere, the operational procedure being displayed on the Okuma OSP control screen. Tuning is performed for movement accuracy by means of compensation offsets fed to the control, based on the measured results. It is common for kinematic errors in a 5-axis CNC machine tool to affect the quality of a finished part. Wear and tear can take its toll on the kinematic chain and result in quality issues. Furthermore, machines drift out of level over time and even the smallest bumps can cause geometric errors. With Okuma's automated system, adjustments can be performed in around 10 minutes, depending on machine size. The process does not require a high level of operator skill. It measures the machine and automatically compensates for all geometric errors as well as volumetric accuracy. The minimised disruption also means that checks can be performed more frequently.