Automatic Handling Technology for Precision Turning of Two-Sided Parts

precision fabrication;transfer;alignment

Furst, Stephen Joseph ; Jeffrey Eischen, Committee Member,Stefan Seelecke, Committee Member,Thomas Dow, Committee Chair,Furst, Stephen Joseph ; Jeffrey Eischen ; Committee Member ; Stefan Seelecke ; Committee Member ; Thomas Dow ; Committee Chair

University:North Carolina State University

关键词: precision fabrication;    transfer;    alignment;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/135/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

ABSTRACTFURST, STEPHEN JOSEPH.Automatic Handling Technology for Precision Turning of Two-Sided Parts.(Under the direction of Dr. Thomas A. Dow.)The fabrication of precision two-sided artifacts is a difficult, time-consuming task.Both sides of such artifacts need to be precision turned on a lathe.Two separate chucks are required to hold the part during machining of the inner contour (IC) and outer contour (OC).Currently, a skilled operator is needed to transfer the part from one chuck to another.To ensure that reference surfaces on both sides are correctly oriented on the machining chuck, the operator must realign the part by measuring run-out with a gage and tapping the part into place.The goal of this study is to develop an automatic transfer and realignment process for a part on a dual-spindle machining center.A hemispherical shell is chosen for demonstration because hemispheres lack “self-aligningâ€Âfeatures, and thus require the most complex handling capability.At the moment of transfer, it is desired to have the axial separation between the part and receiving chuck no less than 125 µm (0.005†).Also, the radial gap between an ideal part and the receiving chuck should vary by less than 8 µm (0.0003†), meaning the radial misalignment between the hemispherical part and spindle centerlines is less than 4 µm.A transfer procedure was developed and demonstrated at the Precision Engineering Center (PEC).The demonstration showed that at the moment of part transfer, the radial misalignment between the part surface and receiving pot chuck was less than 1.5 µm (60µin. ) and the axial position of the part will have an uncertainty of 5 µm.In addition to the transfer procedure, a method was developed to realign the part in the event that radial run-out occurs during transfer.This method involves measuring the magnitude and direction of the radial run-out with either a touch probe mounted to the machine slides or an analog electronic gage.The part is then tapped in the appropriate direction by a mass driven with a voice coil until the part and spindle centerlines are within 5 µm (0.0002†) of each other.A procedure was developed to employ this actuator in part realignment.This procedure was successful in repeatedly repositioned a hemispherical part with an initial run-out of 1-2.5 mm (0.3-1†) to within 5 µm of the spindle centerline.This capability shows that the run-out of a part manually placed on a OC chuck or transferred from an IC chuck to an OC chuck can be corrected.