Yaskawa YASNAC PC NC Programming Manual - Manual (Page 103)

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YASNAC PCNC Programming Manual Chapter 3: Movement Control Commands
FIGURE 3.4.4.26 Offset Motion if Three or More Blocks not Including Axis Move
Commands are Specified in the Offset Mode
(b) Insertion of dummy block
If there are no axis move commands in three consecutive blocks, the cutting tool is posi-
tioned on the normal end point of the block immediately preceding such blocks. If it is
impossible to specify move commands of the axes in the offset plane due to the retraction
motion of the third axis or other reasons and if normal positioning is not desirable, a
dummy block that includes I, J, or K can be inserted in the program. The dummy block
does not call up actual axis movements, but it only gives the data necessary for the calcu-
lation to generate the offset tool paths. In the example program given below, a dummy
block specifying the same movements as given in the block (N020) where the axis move-
ment restarts in the XY plane after the Z-axis movement is inserted in a program;
addresses I and J are used in the dummy block.