ABSTRACTS, cont.

TIME-DEPENDENT EFFECTS OF CONTACT PERTURBATION IN MACHINING
NAMRC41-1610
James Mann, M4 Sciences LLC, West Lafayette, IN, United States, Christopher Saldana, Pennsylvania State University,
University Park, United States
The present study characterizes the effects of modulation amplitude on forces and specific energies in machining
of AA6061-T6. These effects are correlated with tool load duty cycles that vary directly with modulation amplitude.
Closed-form expressions were derived to evaluate fraction of time spent cutting in the presence of modulation.
The duty cycle ratio ranges from 1 to 0.5 depending on the modulation amplitude used for a specific modulation
frequency and spindle frequency combination. When the duty cycle decreased, average machining forces rise
while the apparent average machining forces and specific energies both decrease. Use of apparent average
machining forces for describing tool load profiles was found to be tenuous as maximum load on the tool
actually increases in the presence of modulation. The ability to modify the fraction of time spent cutting has
direct implications for affecting changes in thermal dissipation and interface lubrication, which are important in
characterizing the effects of machining conditions on surface integrity and cutting tool performance.
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