Ram spindle tolerance compensation for horizontal borer

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 runout 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 compensation 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 65.8 %. This can improve the tolerance of the machine, becoming a superior device.