The spindle exact stop function (also known as: spindle positioning function), that is, when the spindle stops, it is controlled to stop at a fixed position. The instruction is M19. The reason for setting exact stop lies in its application, mainly used in:
(1) CNC machine 1165 tool change control: its function is to make the spindle accurately stop at a fixed axial position every time to ensure that the face key on the spindle can be aligned with the keyway on the tool holder during automatic tool change , At the same time, the relative position of the tool holder and the spindle is unchanged every time the tool is installed, which improves the accuracy of repeated installation of the tool, thereby improving the consistency of the hole diameter during hole processing.
(2) Fine boring and retreating of machining center: For example, when boring a large coaxial hole on the inner wall through a small hole on the front wall, or when performing reverse chamfering, the spindle is also required to achieve exact stop, so that the tool tip stops at a fixed point. When the spindle is offset by a certain size, the machining center enables the large blade to enter the box through the small hole on the front wall to boring the large hole.
Working principle:
The exact stop device is installed at the tail of the main shaft, and the coarse positioning plate is fastened to the fine positioning plate with screws. When the machining center stops, the spindle is stopped. The spindle is running before the exact stop.
The spindle of the machining center runs → CNC sends a stop command → the spindle rotates at a low speed (20r/min) → the delay relay delays for a period of time → turns on the non-contact switch power supply → when the inductive block on the coarse positioning plate triggers the non-contact switch → The main motor stops and disconnects the main drive chain → The main shaft continues to rotate due to inertia → The non-contact switch signal sends a signal to the hydraulic cylinder at the same time → The right cavity of the hydraulic cylinder enters the oil → The directional piston moves to the left → The roller rolls on the precision positioning plate →The sheave is jammed.
