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Performance Characteristics of a Developed Non- Circular Boring Attachment

IT Tuleun
TN Guma


Non-circular boring is an unconventional and one of the difficult machining processes on any of the ordinary
machine tools. A non-circular boring attachment, which works on a servomechanism and which can be applied
on engine lathes has been developed. The attachment incorporates a given template and chain drive for power
transmission. The attachment was tested for all the twelve spindle speeds of the lathe, from 22.4 rpm to 1000rpm.
Non-circular bores of good surface finish ranging from 0.23 μm to 6.5 μm were produced, mainly in the spindle
speed range of 22.4 rpm to 180rpm, depth of cut of up to 2mm and feed rate of up to 0.371mm/rev. Experimental
force analysis of the attachment indicated that the cutting forces are linearly or quasi-linearly related to the three
boring variables. Results also show that the cutting forces are dynamic at the start of boring when the cutting is
intermittently around the periphery of the bore until the full shape of the template is obtained.