Single Setup Ballbar Testing of 5-Axis Machine Tools to Identify Position-Independent Geometric Errors

Industry is currently seeking rapid methods to verify the accuracy of five-axis machine tools (5A-MTs) throughout their operational life. The ballbar has previously been reported as a tool used to identify position-independent geometric errors within the rotary axes of 5A-MTs. At present, a minimum of two separate ballbar testing set-ups are necessary to identify eight error sources inherent to two rotary axes. This paper presents a method to identify the same errors with the use of a single ballbar testing set-up. By completely removing the need for operator intervention during or between tests, automation leads to significant reductions in process duration. Error identification is first explained mathematically and later evaluated and proven on a commercial 5A-MT. Finally, compensation of these errors demonstrates significantly improved 5-axis contouring capability.