Machine Tool Feed Path Control for True-Circular Eccentric Machining
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Solution Overview
Problem
In true-circular machining eccentric from a spindle axis, intermittent cutting occurs when the circumferential cutting edge path around the eccentric center position on the X-Y plane is outside the workpiece, leading to tool damage and reduced accuracy, affecting various machine tools including machining centers.
Innovation Solution
A machine tool with a control unit that determines an intermediate center position and eccentric radius for each divided rotation angle, ensuring the cutting edge remains in contact with the workpiece by moving the spindle and tool post in a direction perpendicular to the spindle axis, maintaining a maximum feed speed to prevent intermittent cutting and improve machining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If true-circular machining is performed with a fixed eccentric center position and radius, then the machining path is simple to control, but intermittent cutting occurs when the cutting edge path is outside the workpiece, leading to tool damage and reduced accuracy
Solution Approach 1:
The patent applies dynamics by making the eccentric center position and eccentric radius variable rather than fixed. The control unit dynamically adjusts the intermediate eccentric center position (Pi) and intermediate eccentric radius (ri) for each divided rotation angle based on the current cutting edge position and workpiece geometry, ensuring the cutting edge remains within the workpiece boundaries throughout the machining process.
Solution Approach 2:
The patent changes the parameters of the machining path by calculating and adjusting the intermediate eccentric center position and intermediate eccentric radius for each divided rotation angle. This parameter adjustment ensures that the cutting edge path stays within the workpiece boundaries, preventing intermittent cutting while maintaining continuous engagement with the workpiece material.
2Manufacturing precision
If the cutting edge path is extended to complete true-circular machining, then the machining coverage is improved, but the cutting edge may separate from and contact the workpiece intermittently, increasing tool damage risk
Solution Approach 1:
The patent applies preliminary action by calculating the intermediate eccentric center position and intermediate eccentric radius in advance for each divided rotation angle before actual machining. This pre-calculation ensures that the cutting edge path is predetermined to remain within the workpiece boundaries, preventing intermittent separation and contact that would cause tool damage.
Solution Approach 2:
The patent uses feedback by continuously monitoring the cutting edge position relative to the workpiece boundaries and adjusting the intermediate eccentric center position and radius accordingly. The control unit calculates the optimal path based on the initial position of the cutting edge and the workpiece geometry, ensuring continuous contact throughout the machining process.
3Reliability
If the spindle and tool post are moved to adjust the cutting path, then intermittent cutting can be avoided, but the system complexity and control difficulty increase
Solution Approach 1:
The patent applies universality by making the control unit perform multiple functions: calculating intermediate eccentric center positions, determining intermediate eccentric radii, dividing rotation angles, and generating control commands for both the spindle and tool post movements. This multi-functional approach manages system complexity by consolidating control logic in a single intelligent unit.
Data Source
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AI summary
A technology capable of improving the accuracy of true-circular machining while avoiding an occurrence of intermittent cutting. A control unit U1 of a machine tool 1 determines an intermediate center position (Pi) in the moving direction D1 for each divided rotation angle (E) smaller than a single rotation of the spindle 11 and an intermediate eccentric radius (ri) around the intermediate center position (Pi) according to an initial position (Po) of the cutting edge TOt in contact with the workpiece W1 in the moving direction D1, the eccentric center position (Pc), and the eccentric radius (rc) to keep the cutting edge TOt in contact with the workpiece W1 as the moving object moves in the moving direction D1 within a predetermined maximum feed speed (F) until a true-circular machining around the eccentric center position (Pc) is complete on the workpiece W1. The control unit U1 moves the moving object in the moving direction D1 as the spindle 11 rotates to perform a cutting of the intermediate eccentric radius (ri) around the intermediate eccentric center position (Pi) for each divided rotation angle (E) on the workpiece W1.