PCS acts as the foundation for the entire tool coordinate framework. It is typically located at a neutral position such as the clamping face or taper reference line. This system ensures that all subsequent coordinate systems, including CIP and MCS, are correctly aligned.
Defining PCS accurately is critical because it influences the placement of cutting inserts and component interfaces. Standards like ISO/TS 13399 provide guidelines for PCS definition, promoting interoperability and reducing setup errors in multi-component tool assemblies.