This research work correlates the wear progression and Specific Cutting Energy (SCE) in turning Ti-6Al-4V alloy using H13 tools (uncoated carbide) in dry conditions from low to high cutting speeds. Flank wear growth of the tool has been investigated at different length of cuts in correlation with the SCE under different cutting conditions. The useful tool life was found to be shorter at high-speed machining conditions, as compared to low-speed machining conditions.

Our investigations concern the dynamics of drillstring, experiment apparatus for simulating drillstring vibration was established. Hammering method is used to measure drillstring lateral natural vibration frequency when the internal and external drilling fluid is considered. The test results show that the drilling fluid can decrease the natural frequency of the drillstring. Additional mass coefficient can get the result with high precision, which can meet the needs of the project.

Parallel mechanism (PM) with limbs of embedding structures means that the limbs in the mechanism are connected in the coupling structure, so as to realize limb coupling, and the PM of common axes between limbs. Characterized by the compact structure, low cost and larger workspace, this kind of PM has very broad application prospects in engineering. In this paper, analysis and improvement are carried out on the input of a compact 3-DOF PM with limbs of embedding structures with larger workspace.