HIGH ACCURACY MACHINING STATION FOR A MULTIPLE SPINDLE ROTARY INDEXING MACHINE TOOL

摘要

The invention relates to improvements in themultiple spindle rotary indexing machine tool systemsof the prior art. Traditionally, such machine toolsystems include a base and an upstanding verticalcolumn which houses a plurality of machining stations eachequipped with two-axis tool slides. In addition, thebase supports a rotatable worktable, which carries anumber of work-holding spindles. As the worktablerotates, these spindles are indexed through successivemachining stations where a variety of operations areperformed. In accordance with the invention, a spindleposition measurement unit is provided to dynamicallymeasure the exact location of each spindle indexed toposition at a modified machining station. A computerizednumerical control system calculates spindle positionerrors based on the position information providedby the measurement unit and offsets tool slide positioncommands to compensate for those errors. As a result,the control unit compensates for both fixed and variablespindle position variations, thus improving themachining tolerances of the machine tool apparatus. Inaccordance with another aspect of the invention, a highaccuracy finishing station is provided which includesspindle position variation measurement and compensationin combination with an independent X and Y axis toolslide positioning system. The tool slide positioningsystem is responsive to CNC commands for speed controland position offset due to spindle errors.