This section introduces examples of the third requirement in designing high efficiency equipment,(3) waste elimination.Auto-assembling or machining is generally performed by controlling positions of the drive mechanism of three-axis (X-Y-Z axes).This section explains how to eliminate time waste in controlling the drive mechanism of three-axis.

(1)Time waste in controlling multi-axis drive table operation

・For a two-axis (X and Y axes) drive table, automated task is performed by planar two-dimensional motion control, which is realized by mutual drive control for the two axes.

・Fig. 1 shows machining lines along X-axis and Y-axis for the workpiece.Fig. 2 shows how the table is driven taking speed of motion as the Y-axis, and time as the X-axis based on this figure of machining lines.In this example (motions in the Y-axis and X-axis), positioning is programmed for driving one-cycle machining.

・During this one-cycle machining, the main task is a machining process that is performed while the speed of motion in the X-axis remains stable (indicated by red arrows).Time period other than the above (indicated by gray arrows) is considered to be time waste spent for incidental tasks.

・This control program performs drive control of the two independent axes in a concatenated manner by dividing the X-axis drive time and the Y-axis drive time in order to avoid effects such as vibrations from the Y-axis drive during the X-axis drive time.

(2)Reducing time waste in controlling multi-axis drive table operation

・Assuming that this acceleration and deceleration control is optimal for both X and Y axes in Fig. 2, controlling the drive along the Y-axis excluding the machining time outside the area of the workpiece can reduce time waste equal to the Y-axis drive time. Effects such as vibrations from the Y-axis during the X-axis drive can also be avoided (Fig. 3).

・This control of simultaneous drive for the two axes is called a coordinated operation control (Fig. 4).