UDC 621.91.01 APPROACH TO THE DEVELOPMENT AND TESTING OF POSTPROCESSOR THAT GENERATES WORK WITH MILLING SPINDLE OF MULTI-TASK MACHINE TOOLS © Petar Ivanov Hadjiiski PhD, Professor, Technical University of Sofia, Bulgaria Tsvetan Petrov Kaldashev Technical University of Sofia, Bulgaria Abstract. <...> We present and discuss the possibility to develop a postprocessor that generates NC programs with commands to work with rotated axis milling spindle (G68.1) for multi-task machines. <...> Processing of the workpiece is modelled in the manufacturing module of the Pro/Engineer. <...> The postprocessor is developed by a generalized postprocessor G-POST and specialized language to change the outcome of the postprocessor FIL (Factory Interface Language). <...> G68.1 Xxp where Xp, Y, Zp Y0 Zzp I0J1 K0 R_ G69.1, – coordinates of the center of rotation; I, J, K – direction of the axis of rotation; R – angu lar displacement. <...> Due to the fact that the rotation of the milling spindle is directly linked to the rotation about B-axis, it is in the format of the command G68.1, J=1 address. <...> Fig. 1 shows the significance of the addresses stored in the command G68.1. <...> The direction of rotation of the coordinate system Fig. 1. <...> Addresses meaning and setting of the command to rotate the coordinate system G68.1 The opportunity for the postprocessor to generate command G68.1 rotation of the workpiece coordinate system when working with CNC jig is explored. <...> With the use of this command a local coordinate system rotated around the Y-axis is created. <...> The format of the command is as follows [1]: determines the axis by which is organized the feeding of the tool towards the machined surface to obtain the precise dimensions and shape of the workpiece. <...> By rotating the coordinate system in a clockwise direction (Fig. 2, a) the X-axis is determined as a tool axis and in a counter clockwise direction (Fig. 2, b) – the Z-axis is set as a tool axis. <...> Rotation of the coordinate system: a) clockwise b) counter clockwise APPROACH TO THE DEVELOPMENT AND TESTING OF POSTPROCESSOR THAT GENERATES WORK WITH MILLING SPINDLE WITH MULTI-TASK MACHINE TOOLS Fig. 3. <...> When D=0 – the feeding direction is along the Z-axis and D=1 – the feeding direction is along the X-axis; B – angle of rotation of the milling spindle. <...> Treatment is preceded by a displacement along the [3] (Fig. 4) Y-axis <...>