Sawing Machine Feed Control Using Torque-Based Engagement Detection
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Solution Overview
Problem
Sawing machines face challenges in efficiently transitioning from an idling feed rate to a working feed rate without damaging the sawing tool, particularly due to the slow changeover in existing methods, which leads to increased non-productive times and potential tool overload.
Innovation Solution
The method involves determining a physical variable related to torque transferred from the sawing tool drive, allowing for a rapid changeover from an idling feed rate to a working feed rate using existing electrical sawing tool drive frequency converters, without additional control equipment, by detecting the moment of material engagement and adjusting the feed rate accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feed rate is increased to reduce non-productive times, then productivity is improved, but the sawing tool may be damaged due to excessive speed upon engagement
Solution Approach 1:
The feed rate is made dynamic by automatically adjusting it based on the detected engagement state. The system transitions from a high idling feed rate to a lower working feed rate when material engagement is detected, optimizing both productivity and tool protection without manual intervention.
Solution Approach 2:
The system uses feedback from torque measurements at the frequency converter to detect when the sawing tool engages with the workpiece. This feedback mechanism triggers automatic feed rate adjustment, ensuring the tool is protected while maintaining high productivity during non-cutting phases.
2Measurement precision
If additional sensors are installed to detect engagement timing, then feed rate control precision is improved, but device complexity increases
Solution Approach 1:
The existing frequency converter's torque measurement capability is utilized to detect material engagement. The system serves itself by using already-present components for dual purposes (motor control and engagement detection), eliminating the need for additional sensors or complex control equipment.
Solution Approach 2:
The frequency converter is made multi-functional by using its torque measurement capability not only for motor control but also for detecting when the sawing tool engages with the workpiece. This universal use of existing components avoids adding specialized detection equipment.
Data Source
AI summary
A method for controlling a sawing machine with a sawing tool, which is driven by an electrical sawing tool drive with a first frequency converter, and with a sawing feed device for moving the driven sawing tool at a feed rate in relation to a workpiece to be sawn, and also to such a sawing machine. The feed rate is changed over from an idling feed rate to a working feed rate when the sawing tool engages in the workpiece. A value of a physical variable which corresponds to the torque transferred from the sawing tool drive to the sawing tool or from which a change in this torque can be calculated is determined here at the first frequency converter. The changeover from the idling feed rate to the working feed rate takes place in dependence on the value of this physical variable.