Do we need to have clearance from te CNC manufacturer to implement the FSW head?

No, you do not need permission to mount an FSW head on your machining centre.
Stirweld’s welding head is universal and can be easily installed on any type of CNC. The FSW head behaves like a module added to your CNC. This FSW welding head does not involve any modification of the substance or form of your machine. The manufacturer’s warranty is therefore not engaged.