Cold Extrusion Feed Force Control for Tool Wear Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In cold extrusion processes, the increasing friction between the forming tool and workpiece due to lubricant film degradation and material hardening leads to excessive wear and impaired workpiece quality, as existing methods do not effectively manage the feed force and relative movement to optimize the forming process.
Innovation Solution
A method where the feed force is dynamically controlled by setting a limit value based on the material flow point, allowing for partial forming strokes and return strokes to minimize friction, wear, and optimize the forming process, with the possibility of varying the limit value over the forming length to account for changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the forming stroke is continued without interruption to complete the forming length, then the productivity is improved, but the wear of the forming tool increases due to excessive friction
Solution Approach 1:
The forming process is divided into periodic cycles of partial forming strokes followed by return strokes. The control method monitors friction levels and interrupts the forming stroke periodically when friction reaches a threshold, allowing lubricant replenishment and tool cooling, then resumes forming in subsequent cycles until the complete forming length is achieved.
2Manufacturing precision
If the feed force is increased to maintain forming through friction, then the manufacturing precision is maintained, but the energy consumption increases
Solution Approach 1:
The system performs preliminary monitoring of friction levels during the forming stroke and predicts when friction will reach problematic levels. Based on this prediction, it proactively interrupts the forming stroke before excessive feed force is required, allowing lubricant to be replenished and preventing the need for high energy input to overcome friction.
3Reliability
If the forming stroke is interrupted frequently for lubricant application, then the tool wear is reduced, but the productivity decreases
Solution Approach 1:
The control method continuously monitors friction levels during the forming process and uses this feedback to determine the optimal timing for interrupting the forming stroke. The system balances tool wear prevention with productivity by interrupting only when friction reaches a threshold that would cause excessive wear, rather than using fixed frequent interruptions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes wear on the forming tool, ensures maximum processing quality, and reduces the overall path length and cycle time by only performing backstrokes when necessary, resulting in efficient and high-quality workpiece formation.
Implementation Method 1
the forming tool exerts a compressive force on a workpiece to be formed, which pressure is dimensioned in such a way that the yield point of the material of the workpiece is exceeded. Once the material of the workpiece has begun to flow
Implementation Method 2
the amount of the feed force, as a result of which the relative movement of the forming tool and the workpiece required for forming the workpiece occurs, must be increased. Possible reasons for the need to increase the feed force in the course of the forming process are the gradual breakdown of a lubricant film that has been generated between the forming tool and the workpiece to be formed
Data Source
Figure 1~2
AI summary
In a process for forming a workpiece (5) by extrusion, in particular cold extrusion, a forming tool (2) and a workpiece (5) to be formed are moved relative to each other over a forming length with a forming stroke while forming the workpiece (5), wherein the forming tool (2) and the workpiece (5) are subjected to a feed force relative to each other for forming the workpiece (5). The magnitude of the feed force with which the forming tool (2) and the workpiece (5) are subjected relative to each other while forming the workpiece (5) is measured and compared with a previously defined limit value.If the measured feed force reaches or exceeds the defined limit value, a return stroke is performed after a forming partial stroke over a forming part length. During this return stroke, the forming tool (2) and the workpiece (5) to be formed move away from each other over a return stroke length before the forming tool (2) and the workpiece (5) are moved against each other over a further forming partial stroke over another forming part length. A device (1) for carrying out the above method comprises a forming tool (2) and a motor-driven forming drive (3) provided for this purpose, preferably with a numerical control device (20).If the feed force, measured by a force measuring device (16), with which the forming tool (2) and the workpiece (5) are acted upon against each other by means of the forming drive (3) while forming the workpiece (5), reaches or exceeds a defined limit value, the control device (20) controls the motor-driven forming drive (3) such that, after a partial forming stroke, the forming drive (3) moves the forming tool (2) and the workpiece (5) relative to each other with a return stroke. A machining program running on a numerical control device (20) of the device (1) causes the device (1) to carry out the procedure described above.