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Polycrystalline diamond compact (PDC) cutters are the most extensively used tool for rock drilling in superdeep oil and gas exploration, in which the air drilling technology without drilling fluid is highly promoted. This study examined the performance of PDC cutters in air drilling, including their friction angle, cutting force, specific energy, and wear behaviors, using a home-made testing apparatus and a commercial tribometer. It also investigated the dependence of cutting force on cutting depth and back rake angle. Results obtained in both dry conditions and in drilling fluid media were compared, and a tentative explanation to the observed differences was brought about by these two environments.

Experimental research is carried out to reveal the static frictional behaviors of rubber pipe contact systems. This research is motivated by deep water pipe-laying operations where rubber blocks are used to clamp the pipe to supply sufficient static friction. Within this context, a friction testing instrument has been designed to mimic a situation of the beginning of the pipe-laying installation. Using this instrument, the maximum static friction forces (F) of a rubber pipe contact system are tested. The results show that the ultimate values of the static frictions fluctuate due to the increasing rate of the tangential load (FT). The evolution of contact between rubber and polymethyl methacrylate (PMMA) pipe is observed to identify the formation and propagation of the folds within the apparent contact area. In addition, it is confirmed that the evolution of contact is influenced by the folds and creep of the rubber surface. The creep deformation takes primary effect in accelerating the separation of the interfaces of contact during relative high normal loads (20, 30, 40 N) and low increasing rate of FT; whereas for all of the testing normal loads (10–40 N), the propagation of the folds release the energy which is stored in the interface of rubber when the increasing rate of FT is high. Therefore, the fluctuation of the maximum static friction of the contact system can be regarded as a consequence of interaction of the creep and folds. Furthermore, the instability of the coefficient of static friction in this test has been examined, and it indicated that the creep and folds could affect the static friction distinctly within a certain range of a normal load. This research is beneficial for arranging appropriate normal loads and laying speeds to avoid pipes slipping during a pipe-laying operation.

Under the background of the construction of new engineering and the strategy of “making China 2025”, the society has also put forward new requirements for the personnel training of mechanical specialties. Therefore, combining the training goal of mechanical design, manufacturing and automation in Beijing (Beijing), it is necessary to cultivate new direction and cultivate new growth point for “old” mechanical specialty. And social and economic development has a very important significance.