DETERMINATION OF MINIMAL MACHINING ALLOWANCES IN IRON CASTINGS

S u m m a r y Method of assessing of minimal machining allowances of casts using optical measurement is introduced. Inclination of technological surfaces, their flatness error as well as positioning of the workpiece on the machine tool have been taking into account. The minimal values of allowances are calculated based on the acquired cloud of points representing the surface, which is subsequently substituted with plane according to 3D least square method. Flatness error is calculated and used for determining the value of allowance on single surface by vector analysis. Minimization of volume to be machined by implementing genetic algorithm is presented. Minimal allowances obtained by the method constitute the constraints for further minimization of removed volume. Three sets of casts were measured and minimal machining allowances were determined and compared with ISO 8062:1997 and DIN 1680-1:1980 standards. Optimization of machining allowances results in decreasing the time and costs of manufacturing