| In the machining industry, because of its pollution to environment and harmful threaten to human beings, the usages of oil-type cutting fluid have getting more and more limitation. Green cutting become an encouraged developing technology. In this dissertation, on the current status and characteristics analyzing of such green cutting technology at home and abroad, the systematic research has been carried out on the low temperature air cutting technology.First, the work was conducted to check the feasibility of the replacement of oil-based cutting fluid with water-based cutting fluid. By employment of boiling heat transfer ways, the film boiling critical heat flux and critical superheat degree of water-based cutting fluid has been gained from experiments. Innovatively, it was quantitatively analyzed and determined that the film boiling working temperature of water-based cutting fluid locates in the ranges of 130℃～170℃. The critical heat flux for vaporization of water-based fluid is less than that of water. The water-based cutting fluid, because of invalid in cooling under the state of film boiling, can not exert an effective cooling on the cutting region during the process of machining. A new and more advanced choice is to use the low temperature air injecting fluid instead of the traditional cutting fluid. Combining the refrigeration and machining technology, the dry cold air at -35℃ was gained. With the injecting feeding manner of the cold air for cutting, an application of the green technology is realized in turning manufacturing trials. In order to clarify the cooling and lubrication mechanism of cryogenic cold air, the cutting temperature, cutting forces, wear of cutting tool and cutting chip have been systematically researched with the help of numerical calculation and experiments. The cooling and lubrication effects, as well as the performance of machining quality improvement, enhanced by the low temperature air injecting, have also been analyzed in detail. The results are as follows. Three dimensional temperature fields in cutting tools were numerically computed. The temperature distribution in the cutting region was obtained under the cold air cutting. The relationships, among the cooling effects and cold air temperature, pressure as well as injecting angle, were analyzed and verified in experiments. The experiments, on the effects of cold air injection in cooling, wear of tool, cutting chip behavior and roughness of work pieces, revealed that different injecting angles have different contributions. Sets of optimal injecting angles were obtained from the testing of five injecting angles. The results from the experiment on cutting forces showed that cold air injecting exerts less influence on main cutting forces. The lubrication properties of cold air injection don't behave in the conventional form of friction reducing, but decrease the wear of cutting tool by reducing the plasticity of work piece and tool as well as the enhancement of strength of metal materials and tool. By comparing research on the dry and cold air cutting, it is verified that the cold air decreases the surface plastic property of tool and the cutting temperature, so that the front and back face wears of tool are reduced, and the tool life has been prolonged.Cold air can reduce the surface plasticity of manufactured metals, and improve the chip breaking effects. In the experimental ranges of injecting temperature and pressure, there was no cold-brittle phenomena occurred in metal materials. The pressure of cold air and injecting angle have magnificent influence on chip breaking efficiencies. From the experiments, sets of suitable cold air parameters have been innovated in the precondition to maintain a high manufacturing quality. Cold air injecting can efficiently restrain the accumulated hump of chip and scale fin on the manufactured surface of work pieces, and reduce the roughness of work pieces. Thus, cutting quality can be improved. The above positive roles conclude that the low temperature air inject...
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