Study of deformation and compensation for Ram-Quill type spindle

Ram-Quill combination spindle has been applied widely in Horizontal Boring Milling Machine. It is a great benefit that the machine can be used for various applications. But as the report of experiment, the ram housing bent when it is moved for more than half of its maximum travel. The straightness of Ram housing is out of the tolerance and the run-out of the spindle is way behind the requirement when spindle is at the maximum extension point. This paper proposes an electro-hydraulic monitoring and compensation system which will be able to adjust the pressure to the mechanism in time. The experiments prove that the straightness of horizontal surface can meet the requirement, and a ball bar test at the extremely weak point shows an improvement of the roundness tolerance for 15%. This can make the machine becoming superior equipment for high precision machining.