Bevel and Extraction of Parts

Parts are extracted from the hull model in a number of different functions, for example, in ppanparts for parts from planar panels, in cpanparts for developed shell plates, in tbchm for shell profiles. In all these modules the bevel information is transferred to the parts and may even affect the geometry of the resulting parts. This is all done quite automatically from the information available in the model.

Examples of operations that are performed:

• The bevel variants will be evaluated along inner seams of plane panels.

• The defined bevel gaps will be subtracted from the geometry of the parts.

• The geometry of parts may have to be re-calculated considering the connection angle (see above).

• In case of complicated bevels several contours will be calculated for the control of the different torches in multi-torch cutting, see the figure below

  

  Figure 1:64. Contours required for bevel cutting, most general case.

A is the moulded curve used in modelling,

B is the derived curve for vertical cutting,

C is the curve controlling the cutting of the bevel on the upper side,

D is the curve controlling the cutting of the "under bevel".

Moreover, an envelope curve will be generated as the "union" of the other curves. This curve indicates the area, affected by the complete cutting of the part and thus restricts an area within which no other part may be nested. This curve is called the bump curve of the part (in the figure above it is the union of curves C and D).

The figure above is showing two identical plate edges but with two different ways to calculate the position of the required plate width because of the bevel angle on the lower side of the plate.

By default, variants are taken care of when calculating the addition of material for the different bevel types. This means that the upper material curve is positioned according to point D in the lower view in the figure above.

In older versions of the system, the upper and lower material curves were calculated from the plate thickness of the bounding plate, that means, the e-measure of the current bevel. This means that the upper material curve ends according to the point D in the upper view in the figure above.

By assigning the value NO to the environment variable SBH_ADJUST_FOR_BEVEL_VARIANT, the old way of calculating the material curves will be activated and the upper material curve will be positioned according to the point D in the upper view in the figure above.