When creating a post configurator post processor for a 5-axis mill, the user has the option to set an offset for the center of rotation for the 4th and 5th axes if they are all not aligned in space.
After setting these numbers, the code output does not change. The XYZ coordinates remain the same.
SolutionThere are two requirements for the post to use these offset values.
First, absolute output should be turned off. This is only useful in the case where the 3D model is perfectly aligned to the real machine tool model and its the 4th and 5th axis pivot point. If absolute mode is on, the post will automatically read the MCS zero junction and the local offset and calculate on those values and will not take into consideration the 4th & 5th axis point.
Second, it is important that the operation is under a Fixture Offset local MCS coordinate system. If the operation is under a CSYS Rotation local MCS, these 4th and 5th axis offset points will not be applied. This is a design intent of the post.
Typically, the Main MCS is set at machine zero (wherever that is in space or on the table), and then the local fixture offset MCS is placed wherever the setup dictates.