Research On An Approximation Hole Center Positioning Method And It’s Extended Application

Hole is an important orientation elements and processing, measuring objects ofbox-type workpiece. The processing of large box-type workpiece needs large machine.So it causes the following questions, the first, large workpiece processing needs largemachine, processing time is very expensive. The second, the efficiency of traditionalmeasurement and positioning method is low, and the compensation is inconvenience,so high precision positioning and processing need a lot of time to complete. The last,at home and abroad, the processing gap of large box-type workpiece mainly manifestsin the length of auxiliary time, and the time of measuring and positioning are mainfactors of auxiliary time.Take marine engine box as example, usually the first question of processing isthe correct localization of workpiece in the machine tool. The request that a axis ofbox-type workpiece is parallel to a axis of machine is a most common orientation.The actual survey found that it costs a lot of time. Therefore, how to reduceworkpiece positioning time becomes very meaningful. In order to complete hole heartpositioning rapidly, an approximation hole center positioning method is given byrotating laser displacement sensor without angular coordinate in this paper. Laserdisplacement sensor is installed on the rotatable spindle, and the rotatable spindle isplaced randomly at the different positions around hole center. Spindle is moved alongtwo directions respectively, which are mutually perpendicular and perpendicular withspindle on machine tool, according to the alteration of sensor data when sensor rotatesone revolution, and the curves change trend of sensor data is the smallest (theory iszero), at this time, the axis of hole is coincidence with the axis of spindle at the pointof hole heart. The coordinate value displayed in the machine tool is the coordinate ofhole heart in the machine tool. Write measurement procedures to realize datareceiving, processing and real-time displaying dynamically. Hole pitch measurementis conventional measuring methods for common and time-consuming work. With theapplication of the approximant positioning method of hole heart, two parallel axishole heart can be found quickly and accurately, so as to determine the distancebetween two hole heart. Analysis error source and error effect to get the accuracy of hole pitch measurement.The main work includes the following aspects:1. Research of development present situation and common method for hole heartpositioning.2. Design hole heart positioning system and hole heart positioning measuringprobe.3. Program the software which includes communication of wireless transceivermodule, use serial port to receive sensor measurement data from wireless module,measuring data’s real-time processing, displaying and saving, display measuringresults as the mode of graphics visual.4. Hole heart positioning measurement and experimental verification. Install holeheart positioning measuring probe on the spindle, using hole heart positioning methodto measure the hole heart of standard ring gauge and do hole heart positioningexperiment repeatedly.5. The combination of approximation hole center positioning method and holeheart positioning probe is able to measure hole heart of two shaft hole to be measuredaccurately, through the multiple of measurement, the hole pitch is got. Compare themeasuring hole pitch result to the result which is got from three coordinate machine.6. Analysis error source and error effect of hole heart positioning and hole pitchmeasurement system, make summary and put forward improvement of measurementsystem.