THE SURFACE GRINDING OPTIMIZATION OF TITA-NIUM PARTS WITH DIFFERENT STIFFNESS GIVEN THE PROCESS STABILITY
JOURNAL OF MECHANICS OF CONTINUA AND MATHEMATICAL SCIENCES
This paper considers improving the surface grinding of parts with different stiffness from the titanium alloy VT22 given the process stability based on the multicriteria optimization according to the performance criteria. The part surface quality includes roughness, flatness deviations, micro hardness, relative supporting portion of surface and standard deviation. The variation ranges of the process parameters are as follows: wheel speed v wh = 28m/min, longitudinal feed s long = 5 -18 m/min,
... ng = 5 -18 m/min, transverse feed s tr = 2 -10 mm/ double stroke, depth of cut t = 0.005 -0.02 mm, operational allowance z = 0.1 -0.3 mm. It has been established that the optimal grinding conditions of completely rigid parts given the stability of the process, have not only reduced the standard deviation of the basic parameters by 1.7 times as compared with optimization without taking them into account, but also the basic time of transition by 1.6 times as compared with the recommended standards of grinding. When optimizing the pliable parts grinding (with stiffness j = 350 -11,220 N/mm), the reduction of high-rise indicators of their surface roughness by 1 -2 categorical magnitudes, the standard deviation by 2 times, the basic machining time by 1.2 times for the rough stage, and by 1.2 -3.3 times for the finishing stage compared to the grinding of the completely rigid parts has been noted. The non-rigid parts of titanium alloys should be ground in the longitudinal direction of its variation (by vector s long ). It has been determined that the optimum grinding condition of non-rigid parts allows reducing the main operation time by 4.9 times compared to the standard specifications for completely rigid parts, mainly by increasing t and reducing z. The results obtained should be used in the robust design of grinding operations.