Norbar Case Study
Ensuring Torque Accuracy
Transducerised vs. Non-Transducerised Cordless Tools
Introduction
Torque accuracy is critical in industries where the integrity of bolted joints affects safety, performance, and longevity. This case study compares the performance of transducerised cordless tools, such as the Norbar EBT, with non-transducerised tools, focusing on torque accuracy and consistency under varying conditions like battery voltage, temperature, and joint type.
The Importance of Torque Accuracy
Achieving precise torque is essential in assembly processes across sectors such as automotive, aerospace, and heavy industries. Variations in applied torque can lead to over-tightening or under-tightening, which compromises the reliability and safety of the equipment.
Transducerised tools use a sensitive, calibrated transducer that continuously measures torque during operation, ensuring that the applied torque matches the target. This guarantees consistent accuracy regardless of changes in battery voltage, external temperatures, or the nature of the joint (hard or soft). In contrast, non-transducerised tools rely on current draw algorithms that estimate torque. However, this approach is highly susceptible to external factors, leading to significant inaccuracies.
Comparison: Transducerised Tools vs. Non Transducerised Tools
Norbar EBT – Transducerised Tool
The Norbar EBT is a transducerised cordless tool that provides exceptional torque accuracy. The tool incorporates a transducer that measures the actual applied torque during operation, adjusting in real-time to ensure consistent results, regardless of fluctuations in battery voltage or temperature.
In tests, the Norbar EBT demonstrated consistent torque output even when the battery voltage dropped. For example, when the voltage dropped from 20.89V to 17.38V, the torque remained within the acceptable tolerance range of ±5% from the target torque of 4000 Nm, ensuring accuracy across both hard and soft joints.
Non-Transducerised Tools
Non-transducerised tools operate using a current draw algorithm to estimate torque, which leads to several challenges:
- Battery Dependency: As the battery voltage decreases, so does the tool’s torque accuracy. The tests show a clear drop in torque accuracy from the first to the last trigger pull, with variations of up to 15%.
- Temperature Sensitivity: Temperature fluctuations cause further accuracy drift, making these tools less reliable in extreme environments.
- Joint Type Influence: Whether working with hard or soft joints, non-transducerised tools experience higher variability in torque output due to the lack of real-time adjustments.
For example, as the battery voltage dropped from 40.7V to 33.02V, the non-transducerised tool’s torque output ranged widely, from 3962.1 Nm to 3677.1 Nm, showcasing significant deviations.
Results and Analysis
The data indicates that transducerised tools, such as the Norbar EBT, maintain precise torque control across a range of conditions, ensuring compliance with industry torque specifications. On the other hand, non-transducerised tools experience increasing inaccuracy as the battery drains or environmental conditions change.
This variability is unacceptable in critical applications, where even small deviations in torque can lead to equipment failure or compromised safety.
The Norbar EBT consistently delivered torque within the ±5% tolerance across all tests, while non transducerised tools failed to meet the required accuracy, particularly under adverse conditions.
Conclusion
Investing in transducerised cordless tools like the Norbar EBT ensures greater reliability and torque accuracy, reducing the risk of bolted joint failures and enhancing safety. While non transducerised tools may be less expensive upfront, their susceptibility to environmental factors and battery fluctuations makes them a less reliable choice for applications where precision is critical.
By choosing transducerised tools, companies can ensure consistent assembly quality, reduce downtime due to improper torque, and maintain safety standards across various environments.
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