Posthaste Rotation Angles
Setting up Posthaste for correct Rotation Angle Output:
There is a possibility of incorrect rotary angles being output with "CView Machining" (4 axis indexing of 2 axis toolpaths). The following provides a thorough look at the Posthaste and SURFCAM settings for proper rotational output.
--- Fact # 1 ---
The SET AXIS command in SURFCAM defines a vector that shows which direction the indexer is facing.
Examples:
(0,0,0) (1,0,0) indicates that the indexer is on the left end of the machine table (X-), facing towards the right (X+) end.
(0,0,0) (-1,0,0) (or [1,0,0] [0,0,0]) indicates that the indexer is on the RIGHT end of the machine table (X+), facing towards the LEFT (X-) end.
NOTE: The latter is the "default" setup that most vertical machines use.
--- Fact # 2 ---
The INDEX statement in the post template (PostForm file) indicates which end of the table the indexer is on, which is the OPPOSITE way it is facing.
To set up SURFCAM and the post for the most common 4 axis setup (the latter of the above examples) you would use the following settings:
In SURFCAM , SET AXIS should be (0,0,0) (-1,0,0) or an equivalent value such as (1,0,0) (0,0,0), which is typically facing to the left towards X-, on a standard vertical mill.
In PostForm.m , use INDEX X to indicate that the indexer is on the X+ (right) end of the machine table, which means that it is facing left, matching the above “Set Axis” data.
--- Fact # 3 ---
For consistent correct angle output, the SET AXIS data in SURFCAM must be describing the same rotary table orientation as the PostForm file. While SURFCAM’s vector indicates which direction the indexer is facing, the INDEX line in the template tells the post where the indexer is.
Both areas describe the same data in 2 different ways. To make sure these 2 elements match, keep the following in mind when setting the SET AXIS and INDEX values.
If the Set Axis vector is pointing towards X+, Use "Index X-".
If the Set Axis vector is pointing towards X-, Use "Index X".
NOTE: You must apply the same logic to "B axis" (typically horizontal mill) indexing - using INDEX Y or Y- accordingly.
If you need to reverse the sign to a positive or a negative on the rotary angle, use the MULT -1 modifier on the letter A or B. Do NOT just add or take away the “minus” on the INDEXline in the template.
The default SURFCAM installation has the SET AXIS data as follows in the configuration settings (Tools, Options, NC Defaults, 4 axis, Rotary Options) . For a typical "rotary table on the right" setup we would simply compensate for this by setting the post template to Index X-. Again, you can use the Mult -1 modifier if you need to reverse the sign on your rotary axis letter.
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