A common strategy for multi axis machining of complex geometry is to create a clean core structure to drive the toolpath pattern and use the gouge checking to either retract or project the toolpath onto the actual part surfaces. If this is the approach you are using then the surface feet per minute (SFM) may not be what you expect since the SFM is based off of the clean core surface and not the actual part geometry. As such if the clean core surface is drastically different in size (ie much smaller or much larger) than the part surfaces you will have a different SFM than what you expect.
Have more questions? Submit a request