Study on the CNC grinding machine tool for the radome

The radome is a revolution shell part made of hard and brittle material and has 3-D complex curved surface. The electric thickness of the radome is an important electromagnetic performance index, determined by the geometric thickness and the dielectric constant of the material. For the semi-finished radome, its electric thickness can usually not meet the requirement of the design owing to the error of the geometric thickness and the non-uniformity of the dielectric constant of the material. Therefore, it is necessary to precisely grind the inner surface of the radome to compensate the electric thickness error by altering the geometric thickness. To this end, a three-axis CNC precision measuring and grinding machine tool, which is controlled by a industrial personal computer (IPC) and a programmable multi-Axis controller (PMAC), was designed and developed. In order to avoid installation errors caused by separate loading operation and to ensure the grinding accuracy, the measuring and grinding process of the radome are accomplished in the same installing position on the machine tool in a manner of "once-loading and two-step-operation". First, the inner surface is precisely measured to set up a process datum and then, the finish grinding process is performed based on the datum and the required grinding allowance in the machine tool. It is shown in practice that the radome ground by the machine tool satisfies the requirement for the precision of the electric thickness.