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GH4169 is comparatively a new superalloy mainly used as turbine components because of its outstanding combination properties such as high-temperature strength, thermal stability and wear resistance. But these also make it hard to cut, and its machined surface quality and integrity are particularly sensitive to the manufacturing process employed. The existing researches on machining-induced surface integrity and machinability of hard-to-cut materials are briefly reviewed; the effects of processing parameters on surface integrity for GH4169 components are studied in detail via orthogonal-designed external grinding experiment. The single-factorial plain grinding experiment was designed to further investigate the influence of depth of cut on the surface integrity characteristics. The surface roughness, residual stress distribution, microhardness profile and microstructural alteration within the subsurface were obtained and analyzed. It was shown that the surface integrity is susceptible to the magnitude of depth of cut, and the components ground with low depth of cut are of more acceptable surface quality with less variation in residual stress and microhardness within the machining-affected layer than those obtained with high depth of cut. No severe microstructural alteration or adverse surface cracking was discerned when the depth of cut is reasonably set

The existing automatic control program and its parameters for three machines in a fully mechanized coalmining face are static and simplex and are therefore inadequate for satisfying the complex and dynamic environment of underground coal mines. To overcome this problem, a collaborative mathematical model is established that includes the effects of a dynamic environment. A virtual reality collaborative planning simulator with methods for the three machines is also proposed based on a multi-agent system (MAS). According to the dynamic characteristics of the environment, equipment and technologies, a fully mechanized Unity3D simulator (FMUnitySim) is designed in terms of multiple factors and multiple dimensions. The factors affecting the coordinated operation of the three machines are analyzed and modeled. The communication modes, coordination, and redundant sensing process among multiple agents, which include the shearer agent and the scraper conveyor agent, are also investigated in detail. Using this system, the key parameters of the three machines can be planned and adjusted online to design and distinctly observe the corresponding collaborative simulations of coordinated operation with multiple perspectives and in real time. Tests of different maximum shearer haulage speeds for regular or reverse transporting coal are designed; their key parameters, including the average shearer haulage speed, average follower distance, and average scraper conveyor load, are planned and simulated using FMUnitySim. The optimal parameter combination is obtained by analyzing and comparing the simulation results. The proposed FMUnitySim offers an effective means and theoretical basis for the rapid planning and safe automatic production of a fully mechanized coalmining face.