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Among automated assembly line processes, quality control and consistency are essential. Depending on how products are assembled, rectifying problems with earlier stages of the manufacturing process is not always easy. This can subsequently lead to costly and time-consuming delays.1
To prevent these problems in automated industrial processes, one strategy is to utilize built-in sensors during manufacture. For several applications, such as those in the automotive assembly, one obvious use of sensors in quality control is the inclusion of torque sensors for fastening tools.2
The Right Torque
Tightening nuts and bolts according to the appropriate torque settings guarantees optimal component lifetime and performance. Insufficient torque can cause bolts to vibrate and, in the most serious cases, come loose, leading to component damage and engendering obvious safety hazards. Excessive torque can lead to shearing of the bolt, wasting bolt material and potentially destroying the component’s threading. Even if the bolt withstands the extra force, more profound component fatigue and earlier failure can still occur. The hazards associated with erroneous torque configurations are not limited to the bolts themselves; where bolts are utilized for holding together flanges for fluid systems, insufficient or excessive torque on the bolts that join components can cause damaged gaskets or leaks.3
In automated processing, torque configuration can be checked either via a post-assembly audit, wherein bolts are individually assessed, or via in-built sensors that are designed for utilization with torque wrenches. Since audits are often lengthy and time-consuming processes, online sensors that can be connected to data logging and monitoring represent an attractive alternative, particularly as the same sensors may also be utilized for checking tool calibrations and fluctuations over time.4
The incorporation of torque sensors is also essential for satisfying particular calibration standards criteria. For instance, certain industries enforce requirements for products to have been manufactured according to calibration standards (such as the ANS/ISO/IEC 17025:2005 and ANSI/NCSL Z540.3-2006) which require torque verification and monitoring systems to be established alongside tool calibrations.5
Torque sensors may require very different designs, depending on the desired application. For instance, crankshaft pulleys in engines requiring substantial amounts of torque might be best served with strain-gauged-based torque sensor designs. Typically, these are particularly cost-effective sensors and can cope with significant loads. Among alternative applications where extreme precision is needed, piezoelectric-based sensors are characterized by advanced sensitivity and high stiffness, making them the preferable option for dynamic applications.
HITEC Sensor Developments
As the choice of an application’s optimal sensor is critical, using a company with considerable experience in conventional and bespoke sensor design can be of great benefit. HITEC Sensor Developments, identified as a world-leader in the areas of sensor design and force measurement, possesses 85 years of combined experience in providing just this.6
HITEC Sensor Developments possesses a considerable portfolio of products, comprising numerous categories of torque sensors, vehicle test sensors and load cells.
There are numerous designs within HITEC’s torque sensor range, including an ultra-light torque sensor7 and pulley torque sensors configured according to a cogwheel design. The latter is perfect for applications where conventional detachable pulley gears are unable to fit as a result of space requirements.8 For these sensors, the sensor specifications and size of the cogwheel are all completely customizable.
HITEC Sensor Developments torque sensors are broadly utilized in the paper mill and automotive industries. Their strain gauge sensors are utilized for torque measurements for diesel engine bolts, where the capacity of the sensor to have compensated temperature readouts at engine operating conditions of 350 ◦C helps to guarantee consistently precise torque measurements.9 These torque sensors, configured according to a robust strain gauge design, can be applied directly to a bolt, which means that, when the fastener is used, the consequent force can be recorded straightforwardly, also making it easier to calibrate fastening tools.
The socket sensors range represents another sensor line that is highly suitable for use with manufacturing fastening tools.10 Their integration into fastening tools is simple, and they are suitable for operation with torque loads spanning 25 to 7000 ft-lbs. They also have excellent hysteresis of 0.1% of the full specification operating conditions. Intricately crafted from alloy steel, the socket sensors possess an elastomer coating for protecting against mechanical damage, as well as temperature-compensated outputs ranging from 70 to 170 ◦F. These are based on full, four-arm Wheatstone bridge circuits and can be fitted with SDI connectors for interfacing the sensors with either a single data-logging computer or networked infrastructure, enabling the monitoring and refining of manufacturing processes.
As part of their services, HITEC Sensor Developments supplies a comprehensive support package, comprising a review of the initial application and compatibility of the product, as well as installation and calibration if necessary. Among some applications, protective coatings might be utilized for improving sensor durability and lifetime. These resources, coupled with their in-house expertise in bespoke design applications, allow HITEC Sensor Developments to offer the best service on the market for custom and standard torque sensors used in industrial automation.
- Son, Y. K. (1991). A cost estimation model for advanced manufacturing systems. International Journal of Production Research, 29(3), 441–452. https://doi.org/10.1080/00207549108930081
- Tlusty, J., & Andrews, G. C. (1983). A Critical Review of Sensors for Unmanned Machining. CIRP Annals - Manufacturing Technology, 32(2), 563–572. https://doi.org/10.1016/S0007-8506(07)60184-X
- Sears, G., & King, D. (2004). Joint integrity management of critical flanges. International Journal of Pressure Vessels and Piping, 81(6), 513–519. https://doi.org/10.1016/j.ijpvp.2003.12.021
- Mendoza, M., Mendoza, M., Mendoza, E., & González, E. (2015). Augmented Reality as a Tool of Training for Data Collection on Torque Auditing. Procedia Computer Science, 75(Vare), 5–11. https://doi.org/10.1016/j.procs.2015.12.186
- Calibration Standards (2019), http://www.ncsli.org/i/i/sp/z540/z540s/iMIS/Store/z540s.aspx?hkey=ebe5ca19-e0f7-4c5c-a6dc-70121c857d05
- HITEC Sensors (2019) https://www.hitecsensors.com/about-us/history/
- Ultralight Torque Sensor (2019) https://www.hitecsensors.com/sensor_products/reaction-torque-sensors-ultra-light-torque-sensor-01040/
- Cogwheel Torque Sensors (2019) https://www.hitecsensors.com/sensor_products/torque-sensors-cog-wheel-01034/
- Applications (2019) https://www.hitecsensors.com/applications/automotive/
- Socket Sensors (2019) https://www.hitecsensors.com/sensor_products/reaction-torque-sensors-socket-sensors-01190/
This information has been sourced, reviewed and adapted from materials provided by HITEC Sensor Developments, Inc.
For more information on this source, please visit HITEC Sensor Developments, Inc.