Wire Feed Buffer Control for High-Speed Forming Machines
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Solution Overview
Problem
Highly dynamic forming machines face challenges in feeding elongated workpieces with fluctuating speeds and accelerations, leading to uneven material withdrawal and potential quality issues in produced parts.
Innovation Solution
A method and device that utilize an auxiliary feed device with a buffer store to maintain continuous feeding of workpieces to the forming machine, with a sensor system controlling the conveying speed to manage tension and length variations, and optional tension compensation mechanisms to ensure consistent workpiece delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the reel runs at high speed to meet the forming machine's acceleration demands, then the feed speed increases, but the coil unwinding becomes unstable and material discharge irregularities occur
Solution Approach 1:
The patent applies preliminary action by defining and pre-planning the reel's speed-time profile in advance, starting it a predefined time interval ahead of the feed speed profile. This allows the reel to be prepared and positioned optimally before the actual high-speed feeding begins, ensuring smooth transition and stable unwinding even at high speeds.
Solution Approach 2:
The patent implements dynamics by making the reel speed variable rather than constant. The reel drive controller dynamically adjusts the reel speed according to a predefined speed-time profile that matches the forming machine's intermittent infeed and fluctuating speed requirements, allowing the system to adapt to changing operational conditions while maintaining unwinding stability.
2Productivity
If the feed mechanism uses strong accelerations to meet production demands, then productivity increases, but the restraining forces on the coil create tension and potential stalling
Solution Approach 1:
The patent applies preliminary action by pre-planning the speed-time profile with appropriate acceleration and deceleration phases. The reel is accelerated and positioned in advance according to the predicted feed requirements, allowing strong accelerations to be applied smoothly without sudden force spikes that would create excessive restraining forces on the coil.
Solution Approach 2:
The patent implements dynamics by using variable speed control that dynamically balances the feed mechanism's acceleration demands with the coil's restraining forces. The reel drive controller adjusts speed in real-time according to the predefined profile, ensuring that accelerations are applied at optimal moments when restraining forces are manageable, thereby maintaining both high productivity and force balance.
3Extent of automation
If a predefined speed-time profile is used for reel control, then the feeding process is simplified and automated, but no further control adjustments can be made in response to actual wire feed movement
Solution Approach 1:
The patent applies feedback by continuously monitoring the actual wire feed movement and using this information to make real-time control adjustments. The system compares the actual wire feed speed with the predefined speed-time profile and dynamically adjusts the reel speed to compensate for deviations, ensuring accurate feeding despite variations in material properties or machine conditions.
Solution Approach 2:
The patent implements dynamics by transitioning from a static predefined profile to a dynamic control system that continuously adapts. The reel drive controller uses the predefined profile as a baseline but dynamically modifies it based on real-time feedback from wire feed movement, combining the simplicity of automation with the flexibility of adaptive control.
Data Source
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AI summary
In a method for feeding an elongate workpiece, e.g. a wire (110), to a forming machine (200), the forming machine has a draw-in device (210) for drawing in the fed workpiece and for conveying the workpiece to a tool region (220) of the forming machine, which draw-in device can be operated at varying draw-in speed. A workpiece store (112) is provided in the form of a coil. Workpiece portions are led from the workpiece store to an auxiliary draw-in device (330). The auxiliary draw-in device (330) is driven by means of an auxiliary drive (335) and conveys the workpiece at a specifiable conveying speed into a downstream buffer (350). The workpiece (110) forms a workpiece loop (115) of variable length in the buffer (350), between an inlet (352) and an outlet (354) of the buffer, and is led from the outlet (354) of the buffer (210) to the draw-in device of the forming machine. The degree of filling of the buffer (350) is sensed by means of a sensor system (370). The conveying speed of the auxiliary draw-in device (330) is controlled in accordance with sensor signals of the sensor system.