Edge banding (G108)

The wood machining and furniture industry needs the edge banding function for the exact glueing of veneer strips. When a veneer strip is glued on, the position of the beginning of the edge on different workpieces may differ by several millimeters. Thus, the veneer strip must be cut at a position that is different from the NC block boundary. This is a two-dimensional problem on the XY plane and includes linear and circular movements.

The beginning of the veneer edge is measured by a leading probe (Fig. 16). The measured values are used for determining the exact position at which the veneer edge must be cut.

The following behavior must be achieved:

When the measuring probe is crossed, the interpolator outputs a defined residual path. The system then waits until all axes are inside the control window. Next, an M function of synchronization type MNE_SNS [1]-3 is transferred to the PLC interface that causes the veneer strip to be cut. After acknowledgement, interpolation is continued up to the programmed target point. Only one MNE_SNS-function may be active. This means, multiple programming in one NC-block is not allowed. But the MNE_SNS-function may be programmed together with M-functions of other synchronization types.

Fig.16: Glueing on a veneer strip and edge banding

G108 Edge banding (modal)

Edge banding is activated by the modal function G108. Depending on the settings in the channel parameter list [1]-28 following two methods are possible:

If only one CNC axis is moved, G108 also is allowed without main axis motion. In this special case the measurement can be executed in one of the dragged axis.