Abstract: A system and method for monitoring tool wear in CNC machining operations by monitoring spindle power and extracting instantaneous cutting geometry. The method is based on a physics-based two parameter process model and measuring at two different cutting conditions. The process model parameters are measured with easily accessible spindle power. In contrast to spindle power alone which is influenced by many factors, most especially by variable cutting conditions and by the tool condition, the process model parameters are independent of the geometrically variable cutting conditions and provide a simple and direct measure of tool wear. The two process model parameters change differently depending on the mechanism of the tool wear, specifically flank wear versus cutting edge degradation. This provides a diagnostic for tool wear.

Abstract: A system and method are provided for real-time measurement of tool forces. A relationship between a sensor characteristic and tool forces is determined by first directly measuring tool forces for a standard tool, work piece, and part program in a central facility. A force profile indicative of the tool forces and the standard tool, work piece, and part program are provided to a user at a user facility. The sensor characteristic for a CNC machine at the user facility is then measured for the standard tool, work piece, and part program. Based on the force profile determined at the central facility, the relationship between the sensor characteristic and tool forces is determined. Thereafter, the sensor characteristic of the CNC machine is measured for a work piece, part program and desired tool and converted to tool forces using the relationship between the sensor characteristic and tool forces.

Abstract: A system and method are provided for real-time measurement of tool forces. A relationship between a motor characteristic and tool forces is determined by first directly measuring tool forces for a standard tool, work piece, and part program in a central facility. A force profile indicative of the tool forces and the standard tool, work piece, and part program are provided to a user at a user facility. The motor characteristic for a CNC machine at the user facility is then measured for the standard tool, work piece, and part program. Based on the force profile determined at the central facility, the relationship between the motor characteristic and tool forces is determined. Thereafter, the motor characteristic of the CNC machine is measured for a desired tool, work piece, and part program and converted to tool forces using the relationship between the motor characteristic and tool forces.

Abstract: The present invention provides a method for determining the Frequency Response Function for a collection of tools in a CNC machine by taking four measurements (three of which are independent) on a single tool, held in the same or similar tool holder, spindle and CNC machine. The method uses inverse Receptance Coupling Substructure Analysis (RCSA) to obtain the receptances of the system, exclusive of the single tool. Standard (forward) RCSA is then used with these receptances and certain analytic expressions for the receptances of a freely supported tool to obtain the FRF for each tool in the collection of tools. This information can be used to predict stable, chatter-free depths of cut over a range of spindle speeds in CNC machining, identifying both the limiting depth of cut at any speed as well as special spindle speeds where unusually large, chatter-free depths of cut are available.