CNC Feed Scheduling Based on Spindle Bending Moments
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Solution Overview
Problem
Milling and grinding processes face inefficiencies due to simplistic assumptions about bending moments, leading to high factors of safety and reduced productivity, particularly in machining complex aerospace components where tool breakage is a concern.
Innovation Solution
A method for calculating and scheduling feed rates based on predicted bending moments during CNC machining processes, using a virtual machining simulation environment to determine customized feed rates that account for local forces and axial distances, thereby optimizing tool path parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high factors of safety are used in milling and grinding processes, then tool breakage is prevented, but productivity is reduced and machining time is extended
Solution Approach 1:
The patent implements dynamic feed rate adjustment based on real-time bending moment calculations during machining. The feed rate is continuously modified according to the actual mechanical loading conditions of the tool, allowing the system to operate at higher speeds when conditions permit while preventing tool breakage when loading exceeds thresholds. This dynamic approach replaces static high safety factors with adaptive control.
Solution Approach 2:
The system changes the feed rate parameter dynamically based on calculated bending moments. By monitoring the bending moment at the tool interface and comparing it against threshold values, the system adjusts the feed rate to optimize both productivity and tool safety. This parameter adaptation allows higher overall material removal rates while maintaining reliability.
2Device complexity
If minimal modeling is done to predict cutter breakage, then process complexity is reduced, but manufacturing precision and reliability are compromised
Solution Approach 1:
The patent replaces complex empirical or physics-based modeling approaches with a simplified bending moment calculation method. Instead of using detailed finite element analysis or complex material models, the system calculates bending moments based on basic mechanical principles involving cutting forces and tool overhang distances. This substitution maintains sufficient prediction accuracy while dramatically reducing computational complexity.
3Reliability
If high factors of safety are applied in machining, then tool breakage risk is minimized, but machine and tool utilization is reduced
Solution Approach 1:
The system implements a feedback mechanism where bending moments are continuously calculated during machining operations based on actual cutting conditions. The feed rate is adjusted in real-time based on this feedback, allowing the machine to operate at optimal utilization levels without compromising tool safety. This closed-loop control enables higher overall machine utilization compared to static conservative approaches.
Data Source
AI summary
A feed rate scheduling method may comprise: receiving an engagement geometry of a subtractive component for use in a computer numerical control (CNC) machining process; receiving a tool path for forming a component from a workpiece via the CNC machining process; calculating a plurality of bending moments of a spindle at various intervals along the tool path; and determining a feed rate schedule for the tool path of the subtractive component based on the plurality of bending moment.