Force gauges may not be the most familiar term to engineers and quality control professionals. When asked the question of how to measure force, people might think of load cells, or perhaps think of tensile testing machines or materials testing machines. People could be forgiven for not realizing that force gauges were relatively basic before the dramatic changes in the digital revolution of the 1980s and 1990s. And today, they still play a unique and subtle role that can be difficult to define precisely.
Basic knowledge
A force gauges can be a universal solution for a specific test, or it can be an integral part of a larger testing system. It can be handheld or integrated into a manual or motorized test bench. Its design features make it simple enough for hand-operated testing, yet complex enough to integrate with PLCs, data acquisition software, motorized test stands and other automated equipment. They are commonly used in research, quality control, and production environments.
How do digital force gauges work?
At the heart of a digital force gauge is a strain-based load cell. Strain gauges applied to a load cell stretch and retract when variable forces deform their structure. The deformation of the strain gauge changes the resistance in the circuit, thus relating force to voltage. This signal is converted into a digital signal, further processed by a microprocessor, and converted into lbF, kgF, N and other measurement units for display on an LCD. The load cell is mounted in a metal housing that is strong enough to withstand the maximum rated force. Connected to the load cell is a threaded rod for connecting corresponding accessories, such as hooks, pressure heads, and special clamps.
How to choose the appropriate measuring range for force gauges
Force gauges are available in a variety of ranges and resolutions to suit a variety of applications. For example, a suture manufacturer may need to measure a force of 50N, while a wire harness manufacturer may need to measure 5000N.
For any application, a range should be selected that is as close as possible to the maximum expected force. Because accuracy is usually specified as a percentage of full scale, lower force readings will have increasingly larger errors as a percentage of reading. For example, if the choice of force gauges includes 5, 10, 20 and 50N range models, and the requirement is a 15N force, then the 20N model is most suitable. Generally speaking, a force gauges should be used between 20% and 80% of its range for optimal accuracy and safety factors. sisco provides 0-5N, 0-10N, 0-20N, 0-50N,..., 0-200N, 0-500N force gauges, welcome to shop.
In many applications, the peak force is of most interest, that is, the force at which the specimen breaks, engages, or loosens. This force is often how manufacturers measure the performance of their products. In other cases, a load cell is used to apply a specific force to a sample to determine whether the sample remains intact, such as in wire crimp pull testing.
Although force gauges can be handheld in less demanding applications, best practice is to mount the force gauges on a test bench, actuator mechanism, or other fixture. This type of installation reduces the effects due to operator changes, which can cause inconsistencies in readings. It also helps ensure axial alignment relative to the load cell. Side loading is difficult to avoid during handheld testing and can skew force readings and potentially damage the load cell.
Choose an appropriate force gauges model
Over the years, the variety of force gauges specifications has increased to meet accuracy, physical size, user interface, output, and other requirements. More complex force gauges structures have a range of functions that in the past were relegated to more complex testing machines. For example, upper and lower limits can be configured in a force gauge. An indicator and buzzer alert the operator if results fall outside established reference ranges. Signal output functions can trigger alarms, buzzers or PLCs for integration into production or test stations.
In addition to the simple peak force mentioned earlier, continuous data collection is sometimes required to analyze force versus time or versus distance, when combined with displacement encoders or scales. The force gauge's USB output can be used to transfer data to a PC for tabulation, graphing and further manipulation. Continuous analog output can flow to a data acquisition system.
The data memory provides the user with the ability to save individual peak readings for later download, a useful feature if measurements are taken away from the computer. For special applications that require the acquisition of continuous data at high speed, or where data needs to be acquired over long periods of time, some instruments can acquire this data and store it in memory - thus eliminating the need for data acquisition hardware and software.
Measuring average force over time is a common requirement in the packaging industry, and the external triggering feature accurately captures the force at switch actuation. In busy test environments, high throughput and ergonomics are priorities. Some force gauges achieve these goals through foot switch inputs to activate data output for functions such as data output, data storage, and clear display. These types of functions can also automatically trigger a stop and save data when a sample break is detected. In multi-player environments, concerns about inappropriate use or parameter modification can be eliminated through password protection.
Force gauges usage
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Electronic Appliances: Force gauges are used to test buttons, switches, and other components in electronic appliances like smartphones, laptops, and remote controls to ensure they can withstand repeated use and function reliably.
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Light Industry and Textiles: In the textile and garment industry, force gauges are employed to measure the tensile strength of fabrics, zippers, and buttons, ensuring they meet quality standards.
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Construction Hardware: Construction materials and hardware components, such as fasteners, bolts, and brackets, undergo force testing to guarantee their strength and durability in building and construction applications.
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Lighters and Ignition Devices: Manufacturers of lighters and ignition devices use force gauges to verify the ignition mechanisms' reliability, ensuring safe and consistent performance.
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Fire-Fighting Equipment: Force gauges play a crucial role in testing and certifying the strength of firefighting equipment, such as hoses, nozzles, and couplings, to ensure they can withstand high-pressure situations.
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Pens: The writing pressure and actuation force of pens are measured with force gauges to determine the ease of use and the quality of the writing experience.
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Locks: In the security industry, force gauges are used to assess the durability and resistance of locks, padlocks, and other security devices against tampering and break-ins.
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Fishing Gear: Force gauges assist in evaluating the tension and strength of fishing lines, reels, and other fishing equipment, ensuring they can handle the stress of catching fish.
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Power Machinery: Force gauges are crucial for testing the components of power machinery, including engine parts, gears, and transmission systems, to confirm their durability and performance.
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Scientific Research Institutions: Scientific researchers use force gauges in various experiments and studies, from biomechanics to material science, where precise force measurements are necessary to collect data and draw conclusions.
Calibration of force gauges
Load cells are calibrated using certified weights or a primary standard load cell such as a load cell with indicator. For force gauges with a capacity of approximately 100 lbf or less, a simple benchtop L-shaped stand with hooks and weights is suitable. For load cells with capacities above 100 pounds of force, load cells are more widely used and are often installed in high-capacity force test stands. The fine pitch of this test stand facilitates accurate positioning to load the gage to a specific calibration point. Multiple calibration points can be specified during the calibration process, which helps ensure accuracy even when the linearity of the load cell is not perfect.
The generally recommended calibration interval is one year, however, accuracy verification should be done more frequently, especially if the force gauges has been dropped or overloaded. Overloading does not always damage load cells as they usually have a safe overload capacity of at least 150%
Measuring force quantifies a product's behavior and performance. The force gauges is an invaluable tool for materials, assembly and finished product manufacturers in nearly every industry.
