CNC Machine Calibration


cnc-cmmsThe machine tool industry is developing quickly. Initiatives to improve efficiency, and reduce scrap and production costs have created the need to understand manufacturing processes better than ever before. Knowing the capability of machine tools before metal cutting is the foundation of any machining process. Historically, machine tool rotary axes were confined to large machines, or small indexing tables. As the introduction of smaller 5-axis machines and mill-turn designs increases, so do the challenges associated with their measurement. Both linear axes and rotary axes are subject to errors relative to the intended positioning. This can be due to machine installation errors, collisions or general wear in use. Errors in either the angular positioning accuracy or alignment of the axes can produce significant defects in finished parts. 

CNC Error Mapping & Compensation

The XR20-W rotary axis calibrator works in conjunction with Renishaw XL80 and XM laser systems. The XR20-W consists of an integrated angular retroreflector mounted on a precision servo-controlled axis. The angular position of this axis, and the optics relative to the main body housing, is controlled by a very high accuracy encoder system with the scale directly machined onto the main bearing. Using a Renishaw XR20 Rotary Axis Calibrator coupled with a XL80 linear measurement interferometer, ECM is able to measure all geometric axis in a machine independently and with extreme accuracy. Machine accuracy can then be improved by making targeted alterations to the machine’s assembly using the data to apply error compensation.  

Periodic measurement of a machine’s performance capability is the foundation of process control, providing a known, stable environment in which manufacturing is to be performed. Quantifying process capability reduces costs and improves efficiency.