General properties of contour mode

The process of polynomial contouring is calculated from the geometrical path contour of the main axes in space. The given conditions, e.g. corner deviation or percentage path velocity, result in a position on the original contour from which the contour can be changed or replaced by a contouring curve (polynomial). This means that the starting or target point of the contouring curve which is known on the original path curve.

Using the determined starting and target points of the polynomial of the main axes calculated using the conditions, it is also possible to specify the position of the tracking axes at which their original contour can be replaced by a polynomial.

With tracking axes, as with main axes, a curvature and direction-continuous polynomial is inserted between the corner distances of the pre-block and post-block, taking into consideration the max. acceleration of these axes. However, the originally specified corner deviation refers only to the deviation of the main axis in space so that, if required, an additional limit value can be specified for the maximum deviation of the tracking axes. Any theoretical excess of this deviation by the tracking axis causes a reduction in the contouring curve (reduction in corner distance).

Polynomial contouring is automatically suppressed depending on the transition between the pre-block and post-block if:

• The transition of all axes is mirrored tangentially or directly.
• The transition of the main axes is tangential and no maximum deviation (value = 0) was specified for the tracking axes.
• After programming G61, program end is reached without post-block.

Maximum corner distance, minimum residual block length

In addition, the following restrictions apply in order to generate smooth transitions.

• The corner distance may assume a maximum of 50% of the original block length. If the corner distance selected is greater, the distance of the pre-block and post-block is limited accordingly. If the corner distance at block start and block end is 50% of the original block length, the block is skipped completely.
• When parameterising the contouring function, the minimum residual block length can be set between 0% and 100%. This corresponds to a variable maximum corner distance from 50% to 0%. At every program start, the minimal residual block length is first set to 0% (block can be completely contoured). If the minimum residual block length is specified as 10%, for example, the corner distances of this block can be maximum (100% - 10%) / 2 = 45% of the original block length.
• In circular blocks the maximum corner distance (distance travelled on circle) is limited so that the angle covered does not exceed 90°.