Abstract: Stretching fixation was proposed to improve milling surface quality of TC4 Ti alloy. A plane strain model was developed to analysis the residual stress variation of stretching-fixation milling surface. With a unidirectional mechanical stretching fixture, a stretching-fixation milling experiment was completed on an HSM-600U five axis super-high speed machining center. This was done with the milling speed ranging from 38m/min to 566m/min and the stretching force from 0 to 6330N, and other parameters being kept constant. Surface roughness and residual stress distribution were measured. Experimental results show that stretching fixation has little effect on surface roughness, while increases surface residual compression stress and thickness of residual compression stress layer significantly.

Key words: TC4 Ti alloy, stretching-fixation milling, surface roughness, residual stress, surface quality