The Forming Theory and Computer Simulation of the Rotary Cutting Tools with Helical Teeth and Complex Surfaces
This paper researched the forming theory of the cutting tools with helical teeth and complex surfaces. Deduced the nonlinear equations of the movement of NC system to generate such tools, presented the way to find the solution of the equations, calculated the cross section graphics of the teeth profile and computer simulation of NC machining.
A study on a virtual manufacturing model of a revolving milling cutter in 2-axis numerical control processing
Abstract This paper introduces the same and different points of relative problems in virtually manufacturing a revolving milling cutters that are under two different definitions: equal helix lead cutting edge and equal helix angle cutting edge. The relative problems include the design of the cutting edge curves, the design of the groove and the grinding wheel, the design of the feed speed in 2-axis NC processing, the actual groove curved surface, computer simulation, post-processing, etc. It also gives corresponding common mathematical models and some examples. Finally, some useful conclusions are drawn.
Turbine blade temperature calculation and life estimation - a sensitivity analysis
Abstract The overall operating cost of the modern gas turbines is greatly influenced by the durability of hot section components operating at high temperatures. In turbine operating conditions, some defects may occur which can decrease hot section life. In the present paper, methods used for calculating blade temperature and life are demonstrated and validated. Using these methods, a set of sensitivity analyses on the parameters affecting temperature and life of a high pressure, high temperature turbine first stage blade is carried out. Investigated uncertainties are: (1) blade coating thickness, (2) coolant inlet pressure and temperature (as a result of secondary air system), and (3) gas turbine load variation. Results show that increasing thermal barrier coating thickness by 3 times, leads to rise in the blade life by 9 times. In addition, considering inlet cooling temperature and pressure, deviation in temperature has greater effect on blade life. One of the interesting points that can be realized from the results is that 300 hours operation at 70% load can be equal to one hour operation at base load.