Point to Point Programming
The point to point programming is carried using the following vocabulary words
GOTO for absolute positioning
GODLTA for incremental positioning
GOTO is used to move the spindle from the current position to the point specified in the statement. The general format is
GOTO/ x, y
GOTO/ x, y, z
GOTO/ point
When no Z-value is specified, it is taken from ZSURF in force.
Alternatively GODLTA can be used for incremental positioning as follows:
GODLTA/ dx, dy, dz
GODLTA/ dz
GODLTA/ vector
This results in moving dx along X-axis, dy along Y-axis and dz along Z-axis from the current position. If only one value is specified, it refers to Z-axis.
The actual operation carried out at these points depends on the postprocessor statement CYCLE.
The GOTO statement can also be used to move the tool to a number of points if they are already grouped as a pattern as follows:
GOTO/ pat1
When GOTO is used to move to a pattern the actual path of the tool will be to all the points specified in the pattern in the same order as their definition. However, it is possible to change the order as well as the actual points visited by using modifiers as follows:
AVOID : Avoid the specified points in drilling operation
CONST : Constant as used for numbering sequence in pattern drilling
INVERS : To specify the numbering sequence in reverse order
THRU : All the points through
OMIT : Tool will not visit the specified points
RETAIN : Tool will visit only the specified points
Since GOTO being a point to point command the tool will be moving rapid to the specified point with the assumption being there are no obstructions in between. If there is any obstruction such as the work holding clamping is present then the tool will have to move in Z-axis to clear the obstruction and then go to the programmed point. This is achieved by using the AVOID modifier. The statement
GOTO/PAT1, AVOID, 15, 2, 4.