Opening Faces


Usually for mechanical reasons, primary breakdown solutions are sometimes required to have opening faces. An opening face can be on the top or bottom or left or right side of the log. It is a guarantee that some of the log surface will be milled off in the primary break down. RL uses these terms in sort of an ad hoc manner some of which is described in the figure below. The opening face is computed differently on the sides than it is on the top or bottom.



Side Opening Faces

Looking at the side view above, the values of A, B and C are important for the opening face on the left or the right. These values are computed from configration parameters. The value of C is LeftMinFace on the left side and RightMinFace on the right side. To compute the value of A and B the parameter LeftFlitchFaceIgnoreFraction is used on the left. The value of A is this IgnoreFraction parameter times the log length rounded down to a multiple of two feet. Of course, B = Log Length - A. (Note A could be zero even if the IgnoreFraction parameter is non-zero.) Some typical values are given it the table below. A IgnoreFraction of one or more turns off the left or right opening face requirement, this is the default. (A negative value for MinFace will also turn off the opening face requirement.)


Face Length in feet vs Ignore Fraction (1st Column) & Log Length in feet (1st Row)
  8 10 12 14 16 18 20
0.1 8 10 12 14 16 18 18
0.12 8 10 12 14 16 16 18
0.125 8 10 12 14 14 16 18
0.15 8 10 12 12 14 16 18
0.167 8 10 10 12 14 16 18
0.2 8 8 10 12 14 16 16
0.25 6 8 10 12 14 14 16
0.334 6 8 8 10 12 12 14
0.5 4 6 6 8 8 10 10
0.667 4 4 4 6 6 6 8
1.0 0 0 0 0 0 0 0


Top and Bottom Opening Faces

This feature is available in curve cant mode. The figure above has the different values D and E dealing with the top or bottom opening faces. Similar to the value C, there are TopMinFace and BotMinFace parameters. However the values of D and E are computed completely different. The parameters in question are MinCantFaceStartFromTip and MinCantFaceEndFromTip with default values of two feet and eight feet. This minimum face is only require to exist between 2-8 feet in this example. If the log is a prefect shape, the face will extend all the way back to the butt as shown in the figure but it is not required. Thus the length D + E is often shorter than the log length. Here D is 2, the MinCantFaceStartFromTip and E is at least 6 = 8 - 2 = StopFromTip - StartFromTip. The StartFromTip is rounded down to a multiple of two and the StopFromTip is rounded up to a multiple of two. Top and bottom opening faces are available only in curve cant mode. (A negative value for MinFace will also turn off the top or bottom opening face requirement.)

Top anb Bottom opening faces are now on a cant by cant basis. The is a different parameter for each cant width of 4 inch, 6 inch, 8 inch, 10 inch, 12 inch and 5Q width. (added 10 Apr 1998.)


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