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Universal Load Cells 101

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In the force measurement testing world, versatility has tremendous value. That is why some of Interface’s most popular products are designed to provide adaptability for a broad spectrum of testing and force monitoring processes.

These products are engineered for universal use cases, from standard tension and compression LowProfile Load Cells to Interface’s multi-axis sensors that can measure up to 6 axes for additional data.

Universal load cells can measure both tension and compression forces in testing and monitoring applications. Universal load cells provide the ability to capture data on both forces. They are designed for a broad scope of force or weight measurement applications such as weighing scales, material testing machines, and industrial automation equipment.

These load cells are ideal for installations where the load may change from tension to compression. Universal load cells also suit various product and material destructive testing as they are robust and easily mounted in various applications.

Top Benefits of Universal Load Cells

Range of Standard Capacities: Universal load cells are diverse in dimension and capacities. From miniatures like our model ULC, which is the world’s most accurate ultra-low capacity tension and compression load cell measuring loads from 0.1 to 2 N (10.2 grams to 500 gmf) to 1000 Series High Capacity Fatigue Rated LowProfile Load Cell capable of measuring tension and compression over a million pounds of force, Interface has a range of universal options. The requirements of any testing program will define the type of load cell.

Versatility: Universal load cells can measure force in multiple directions, including compression, tension, and shear forces.

Adaptable Accessories: Universal load cells can be used with various accessories and fixtures to suit specific applications. This includes bases, mounting hardware, adapters, cables and protective enclosures. Wireless sensor options are in high demand for universal load cells.

Engineered to Order: Interface offers engineered to order and customization of our load cells to further the application use and flexibility of use.

Products such as universal load cells appeal to highly regulated industries like aerospace, defense, automotive, and industrial automation. In controlled testing, engineers must meet stringent performance measurement standards for components, equipment, and machinery.

Another area in which universal load cells stand out is in material testing. Measuring tension and compression provides critical force data when testing a material that will be used in system that needs to be both strong and flexible for safety and quality purposes.

One of Interface’s most popular load cell model, the 1200 series, is universal. For example, Interface’s Model 1200 and 1201 Series IO-Link Universal Load Cells are pancake style load cells which are IO-Link compatible with an open standard serial communication protocol that allows for the bi-directional exchange of data from sensors and devices.  We also offer a 1200 and 1201 Series 3-Wire Amplified Universal Load Cell.

Features and benefits of the 1200 and 1201 Series IO-Link Universal Load Cell include:

  • Proprietary Interface strain gages
  • Temperature compensated
  • Eccentric load compensated
  • Low deflection
  • Shunt calibration
  • Tension and compression
  • Compact size
  • 3-wire internal amp choice of 4-20 mA, ±5V, ±10V, 0-5V, 0-10V

Patient Hoyer Lift

A Hoyer lift is used to move patients. A medical equipment manufacturer would like a force system to weigh disabled patients and measure the maximum force when using the equipment. Interface’s WTS 1200 Precision LowProfile Wireless Load Cell is attached to the top of the Hoyer lift. The tension and compression force results are wirelessly transmitted to the medical personal’s computer through the WTS-BS-6 Wireless Telemetry Dongle Base Station. Interface’s wireless force system was able to measure the amount of weight a patient while also clarifying the maximum capacity the Hoyer lift can hold during use. Read more about this application here.

If you need a little more flexibility in your testing and monitoring system, Interface universal load cells may be a great option for you.  The choice of a specific load cell will depend on factors such as the required load capacity, accuracy, environmental conditions, and signal compatibility with the rest of the measurement or control system.

ADDITIONAL RESOURCES

Interface 101 Series

Wireless Telemetry Systems 101

Load Cell Sensitivity 101

LowProfile Load Cells 101

ITCA Tension and Compression Load Cell

 

Force Measurement is Fundamental in Material Testing

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Material tests are run to determine the quality, durability, and resistance of materials for parts and products. Selecting the right material is critical to performance of a product, system, or part, especially as it relates to the environmental factors. It is also core for adhering to regulatory standards and compliance requirements.

Whether it is construction and concrete materials, metals, fabrics, biomaterial, plastics, packaging, or some other matter, material testing is fundamental throughout the entire development lifecycle.

Among the various ways to test materials, force measurement is one of the most important. Common uses of force measurement in material tests include applications to measure hardness, torsion, strength, compression, bending, shear, impact, creep, fatigue, and nondestructive capabilities.

The use of load cells provides an adaptable tool that can be utilized for various types of material tests. Using force measurement sensors help to detect changes in load, which is used to determine the flexibility, strength, or weakness of properties in materials. This is critical for research and quality control.

For example, in metal material testing load cells are frequently used for characterizing and assessing the quality of metallic components and structures. Material test engineers use load cells to accurately measure the tensile strength, compression resistance, and yield properties of metal samples. By subjecting metals to controlled loads and monitoring the metals deformation during tests, Interface load cells provide critical data that informs engineering decisions and quality control processes. Material tests confirm that the metals chosen for products like aircraft structures, automotive components, and sports equipment, meet stringent performance standards. The measurement sensors are also vital for determining the reliability, longevity and safety of metal materials used for any product or part. See other examples of testing in our new Interface T&M Material Testing Overview.

It is the responsibility of a material testing engineer to determine the resilience, safety, and value of materials through mechanical testing, of which material testing is one of the five categories. Ultimately, product designers and original equipment manufacturers (OEMs) rely upon material testing data to ensure their products can withstand the anticipated levels of force during use. They also need to know if the material will stretch or elongate, as well as pinpoint its exact breaking point.

Interface’s robust line of load cells, multi-axis sensors, and data acquisition systems are used for material testing. It is common to have our 1200 LowProfile load cells installed into material testing machines at test labs and onsite. We also supply a variety of miniature load cells and load pins for material testing, depending on the type of equipment and environment used for tests.

High accuracy load cells are essential in material testing due to their precision, versatility, and ability to provide real-time data, which helps researchers and engineers gain a better understanding of a material’s mechanical properties and behavior under different conditions.

If force must be measured, Interface has a solution. This applies to testing materials used for infrastructure, medical devices, aircraft, rockets, vehicles, robotics and consumer goods. As new materials and composites are introduced in revolutionary ways for use in construction, designing light weight products using polymers, and 3D printed components, it is imperative that material tests validate the use case based on high accuracy measurements.

Our force measurement products are being used to gather data from testing materials in applications used for machines, equipment, structures, packaging and more. Here are a few examples of material testing applications.

Inflatable Space Habitat

Inflatable habitats are the newest innovation in the space industry, creating a new interplanetary dwelling for humans to live and work past the Earth’s atmosphere. An innovative space industry company wanted to test the overall design and material of their inflatable habitats by conducting a burst test. Multiple clevises and LP Stainless Steel Load Pins were attached to the in the webbing material that create the inflatable habitat. When pressure was increased within the inflatable habitat, the load pins captured how much force the heavy duty material will hold at specific pressures until it explodes. Interface’s LP Stainless Steel Load Pins successfully measured the amount of force the inflatable habitat could withstand during the burst test.

Material Tensile Testing Load Frame

A customer wanted to conduct a tensile force test on different samples and materials until failure. Materials include plastic, steel, or woven fabric. They wanted to measure tensile strength, yield strength, and yield stress. Interface’s 1200 Standard Precision LowProfile™ Load Cell was installed into the customer’s test frame. The tensile test was conducted, and force results were captured by the load cell and extensometer were synced through the SI-USB4 4 Channel USB Interface Module. These results were then displayed on the customer’s PC with supplied software. With Interface’s force products, the customer was able to determine the tensile strength, yield strength, and yield stress of a variety of different materials.

Material testing is often the first step in any new product development process. With Interface force measurement solutions, our customers can expect industry-leading accuracy, quality and reliability in testing the materials that will go into their next project. Contact us for products used for various test types.

Interface Solutions for Material Testing Engineers

Tensile Testing for 3D Materials

Bending Beam Load Cell Basics

The Aviation Industry Soars Using Interface Solutions

Interface Solutions for Structural Testing

Interface Solutions Aid Pharmaceutical Industry

Interface Solutions Aid Pharmaceutical Industry

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Among the many highly regulated and incredibly complex industries, the medical industry is highly dependent on tools and resources that are precise and measure with high accuracy.

The medical industry is a broad, encompassing hospitals, medical professionals, payers, medical devices and pharmaceuticals. In each sector, Interface has a long history of providing precision measurement solutions for R&D, prototyping, testing, manufacturing, packaging and monitoring use.

In every use case, safety of patients and quality of products is predicated on extreme accurateness. Throughout a pharmaceutical product’s life cycle, specialized measurement equipment and sensor technologies are used by scientists, engineers, researchers, lab technicians, regulators, quality groups and manufacturers. These instruments are utilized in design and maintenance to provide unmistakable evidence of process quality and safety.

Medical and healthcare companies, including those specifically in pharmaceuticals, turn to Interface because our high accuracy force measurement solutions are designed for reliable performance test and measurement projects. The science used in the pharmaceutical industry depends on quality measurement of force and weight. Interface load cells are designed for these types of precise requirements. There is also tremendous demand for Interface’s ability to customize solutions that meet the exact measurement requirements of these sensitive applications. Visit our new Interface Pharmaceutical Industry Solutions.

Interface supports a range of pharmaceutical applications including:

  • Weighing and distributing
  • Specimen testing equipment
  • Tablet hardness testing
  • Tablet forming machine optimization
  • Capsule filling machines
  • Quality control and safety
  • Mixing
  • Packaging and filling
  • Bioreactors and fermenters

Interface force measurement solutions are used for a variety of pharma-related products and machines that help biotechnology and pharmaceutical product engineers to design, test, and manufacture their products.  When it comes to equipment used in the manufacturing of medicine, Interface products are used to optimize production and reduce waste. Our miniature load cells are often integrated into machines and equipment to provide precision measurements during operations.

Types of Interface Load Cells Used by Pharmaceutical Companies

Pharmaceutical Tablet Forming Machine Optimization

A pharmaceutical tablet producer wanted to monitor the forces applied by the tablet forming machine to understand the relationship between raw material, die set, forming force, and the motor’s cycle speed. The goal was to improve productivity and efficiency of the tablet forming process, while reducing losses such as cracked tablets or voids, by adding a dimension of feedback that could be used to assign specific press adjustment criterion for given inputs. An Interface WMC Sealed Stainless Steel Mini Load Cell (10K lbf Capacity) was mounted in the section of the downward press bar. The machine was modified to accomplish this. The load cell was then connected to a 9320 Portable Load Cell Indicator to collect the needed data. After analyzing the data, the tablet producer was able to quantify adjustment levels by monitoring which forces produced the most optimal results for a given cycle speed, die set, and raw material. Productivity and efficiency were greatly improved by the enhancement of the data feedback.

Tablet Hardness Testing for Pharmaceuticals

A pharmaceutical producer wanted to test and monitor the hardness of the pills being created in their tablet forming machine. Interface’s SML Low Height S-Type Load Cell was mounted to the hardness device inside the tablet forming machine. The SML Low Height S-Type Load Cell was then connected to the 9870 High-Speed High Performance TEDS Ready Indicator to record the force measurements. The tablet producer was able to verify and test the specific hardness needed for their tablets being produced by their tablet forming machine.

Pharmaceutical Tablet Machine Hardness Calibration

A customer wanted to regularly recalibrate tablet hardness testers. The customer needed a miniature load cell the size of a sugar cube that replaces the tablets and fits horizontally in the tablet test-box. Therefore, a special cable exit was important for the compression only calibration application. In the past, the machines had to be rebuilt for calibrations, or a complex mechanism had to be integrated to enable vertical calibration. However, Interface’s MCC Miniature Compression Load Cell measures forces on its side with a special cable exit on the flat side that attaches to the calibration indicator, such as the Interface handheld indicator and datalogger Model 9330. The MCC load-cell calibration set compared the applied forces with the hardness tester to make sure that the tablet hardness tester uses the correct force for future tablet hardness tests. The BlueDAQ software helped to log and compare the data of the MCC reference load cell. The customer successfully verified and calibrated the tablet hardness tester machine horizontally to conduct accurate hardness testing on tablets in the future. Interface’s MCC Miniature Compression Load Cell was perfect due to its small size, and convenient to measure the forces on its side.

Like medical devices, pharmaceutical machines and products must undergo a variety of mission-critical tests before they are safe for distribution to uses. Interface products are selected by the pharmaceutical industry is due to our product’s accuracy and reliability, in addition to our deep experience in supplying solutions to those in the medical business.

Pharmaceuticals_InfographicPoster

ADDITIONAL RESOURCES

Spotlighting Medical Device and Healthcare Solutions

Force Solutions for Medical Tablet Forming Machines

Interface Ensures Premium Accuracy and Reliability for Medical Applications

Interface Solutions for Medical Devices and Healthcare

Interface Solutions for Safety and Regulation Testing and Monitoring

Accuracy Matters for Weighing and Scales

 

Advancing Battery Possibilities with Measurement Solutions

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Advancements in batteries have opened new possibilities for the types of cars we drive, products we use in our homes, and even the way we store energy. Force measurement solutions play a crucial role in supporting advancements and innovation in battery technologies, as noted in Advancing Lithium-Ion Battery Test and Measurement.

The primary areas for battery developement utilizing Interface load cells and instrumentation are design, testing, and manufacturing. From structural integrity and safety tests to material testing and optimization, Interface measurement solutions are used for evolving batteries and their applications across many industries.

Interface is a preferred provider of force measurment solutions to the automotive industry, where they have long utilized our load cells and instrumentation for different battery testing. Learn more about our battery solutions for the auto and vehicle industry here.

As batteries become more powerful, ensuring their structural integrity for safety purposes becomes paramount. Our load cells are used to accurately measure the forces during various mechanical stresses, such as compression and impact testing. These measurement solutions can help to assess their robustness and identify potential weak points of the battery structure. Read: Electric Vehicle Structural Battery Testing

Understanding how battery materials respond to forces is critical in optimizing their performance and durability. Testing new materials is critical in developing new battery capabilities and capacities. With the introduction of new battery types, there is a requirement to thoroughly assess the chemicals and materials used in the battery, it’s encasing and the surrounding environment.

Load cells can be integrated into battery testing setups to monitor the mechanical stress on batteries during charge and discharge cycles. Load cells are utilized in thermal testing chambers to measure the mechanical stress experienced by batteries during thermal cycling. Load cells that are designed for high cycle counts for fatigue and stress testing are ideal for this type of measurement.

Interface products are important in the quality control processes of battery manufacturing. By validating the mechanical properties of batteries at different production stages, manufacturers can maintain consistent quality and comply with industry standards and safety regulations. All types of batteries are regulated in many countries to ensure safety, environmental protection, and consumer rights. The specific regulations may vary; however, most batteries are designed to meet the maximum industry standards.

Advancements in battery testing are essential for a wide range of industries that rely on batteries as a crucial component of their products or operations. Some of the industries that heavily rely on battery testing include automotive, particularly electric vehicles (EVs), renewable energy, consumer electronics, manufacturers, aerospace and aviation, medical devices, military, industrial equipment,, transportation and shipping, and maritime.

How are load cells used in battery testing?

The most common types of battery testing include capacity testing, safety testing, environmental testing, and manufacturing quality control. Load cells are commonly used for battery compression tests, impact testing, and thermal expansion and contraction.

Battery Compression Testing

This is crucial to ensure the battery’s structural integrity and safety under different conditions. During compression testing, the battery is subjected to controlled forces using hydraulic or mechanical presses, and load cells placed between the battery and the press measure the applied force accurately. Engineers can analyze the data to determine how the battery deforms and behaves under pressure, helping them design safer and more robust battery packs.

Interface low profile load cells, like our popular 1200 series or through-hole load cells like our precision load washers are often used for compression tests on batteries. Low profile load cells have a flat, disk-like shape and are suitable for applications where the force needs to be applied in a perpendicular direction to the cell’s surface. Through-hole load cells, on the other hand, have a central hole through which the force is applied, making them suitable for applications where the load needs to pass through the load cell.  Interface offers a wide range of models including high-capacity, compression-only, precision, and mounting options for our load cells.

Battery Impact Testing

Load cells can be integrated into a machine, drop tower or other testing setups, where the battery is dropped from a specific height to create impact. The load cells measure the impact force experienced by the battery during the fall. This data is vital for evaluating the battery’s ability to withstand sudden shocks and impacts, ensuring it meets safety standards for real-world situations.

For impact testing, high-capacity load cells with a rugged and robust design are preferred. Impact events can generate high forces in a short period, so the load cells must be capable of handling such sudden loads without damage. Interface’s S-type load cells or rod-end load cells are commonly used for impact testing applications due to their ability to measure tension and compression forces accurately.

Battery Thermal Expansion and Contraction Testing

Load cells are used in thermal testing chambers to measure the changes in mechanical stress that occur within the battery as the temperature fluctuates. By analyzing how the load on the cells changes with temperature, engineers can assess the battery’s performance and structural stability under different thermal conditions, which is critical for battery design and optimization.

In thermal testing applications, miniature load cells often used. Miniature WMC load cells are compact and can be easily integrated into small spaces within thermal chambers. Strain gages offer excellent sensitivity and are suitable for measuring small changes in mechanical stress that occur during thermal expansion and contraction testing.

Read EV Battery Testing Solutions Utilize Interface Mini Load Cells

Interface Force Load Cell Considerations Used for Battery Testing

  • Capacity: Choose a load cell with a capacity that covers the expected force range during testing. Ensure that the load cell can handle the maximum force that might be applied during compression, impact, or thermal testing.
  • Accuracy: Look for load cells with high accuracy and low hysteresis to ensure precise and repeatable measurements, especially when evaluating the mechanical properties and behavior of EV batteries under various test conditions. Interface is known for accuracy in measurement. All specifications related to the accuracy are available on each product’s datasheet.
  • Model Design: The load cell’s form factor should be robust and durable to withstand the demands of testing. A rugged design, preferrably stainless steel, is essential for impact testing and to ensure the load cell remains stable and reliable throughout the testing process.
  • Compatibility: Ensure that the measurement device is compatible with the testing equipment and data acquisition system being used in the battery testing setup. Interface will work with you in selecting the right sensor, instrumentation, cable and any accessories based on your test plan.
  • Calibration and Temperature Compensation: All Interface load cells have calibration certificates. The temperature compensation features are outlined in the model specifications. Accurate calibration and temperature compensation are vital for obtaining reliable and accurate force measurements, especially during thermal testing.
  • Application-specific features: Depending on the type of battery testing, certain load cell features, such as high-frequency response for impact testing or low profile designs for compression testing in confined spaces, might be beneficial. Discuss with our application engineers if you have questions on selecting the right products.

Overall, advancements in battery testing have far-reaching implications across various industries, enabling the development and deployment of safer, more efficient, and higher-performing battery technologies, which are essential for the ongoing transition to a sustainable and electrified future. To learn more about solutions that Interface has supplied for battery testing, and affiliated components used in the advancements of batteries, contact us. Our solutions team is ready to help.

Additional Resources

Electric Vehicle Battery Load Testing Feature and Application

Feature Article Highlights Interface Solutions for EV Battery Testing

EV Battery Testing Solutions Utilize Interface Mini Load Cells

Advancing Lithium-Ion Battery Test and Measurement

Electric Vehicle Structural Battery Testing App Note

Electric Vehicle Battery Monitoring

Interface Powers Smart Transportation Solutions

 

Load Pins 101

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A load pin is a type of load cell that can replace bolts, clevis, sheave, and equalizer pins, as well as other load-bearing components to measure tensile and compression forces. Load pins are internally gauged with a bored center containing strain gauges, allowing them to convert force into an electrical signal for engineers to accurately collect data.

Most applications for load pins in the past have been for overhead equipment like cranes and lifts. Load pins have expanded in popularity and are now often used to test and measure force, load, and limitations in a much larger variety of applications. This includes uses not only for cranes and lifting devices, but also construction equipment, industrial machines, nautical craft and equipment, aerospace, and civil engineering applications. A primary system approach with structural applications is for safety and to prevent excesses in loading and lifting.

New model types with wireless and Bluetooth technology are also resulting in more use cases for these specialized force measurement solutions. This applies to both test and measurement as well as for installed OEM components within a larger structure or apparatus.

Top Load Pin Benefits

  • Easy to install new or retrofit
  • Robust construction
  • Replaces existing load bearing pins without any system modifications
  • Engineered to order designs available
  • Can be supplied with integral connector
  • Custom sizes and higher capacities available

Load pins come in many standard shapes and sizes, as well customization options to meet a specific design or use requirement. Interface provides these measuring devices, which often replace a bolt or pin, for safety and application monitoring. Some of our load pins are exclusively designed to meet the needs of applications in hazardous environments like the oil and gas industry, or marine industry where they’ll be submerged in water during testing and for continuous use.

The Interface Load Pins are machined from high tensile stainless steel and are suitable for exposed situations including seawater. We offer standard load pins with ratings between 1.1K lbf to 3.3M lbf (500kgs to 1500 MT). We also offer custom manufactured load pins suit applications from 100 kgs to 1500+ MT.

LP Stainless-Steel Load Pin – Great for lifting applications for both short and long distances. This product can be amplified with 5VDC, 10VDC or 4-20mA Outputs. It can also be made to meet ATEX requirements. Model LP Load pin is available in capacities up to 3,000,000 lbf (13.3 kN).

WTSLP Wireless Stainless-Steel Load Pin – This advanced load can transmit wirelessly up to 600 (1,969 feet) meters in distance (clear line of sight) to a handheld display or USB base station.  The capacities range goes all the way up to 3,000,000 lbf (13.3 kN). The wireless option utilizes low power consumption for long battery life. It is configured and calibrated via PC using a base station and telemetry toolkit and compatible with Interface WTS Wireless products. The load pin is robust and uses a lightweight housing. It is environmentally sealed to IP67.

Load Pin Application

One of the largest scale applications of load pins we provided were used to measure force on a large bridge infrastructure project in the western U.S. The goal was to continuously monitor the standard force created by regular traffic, as well as the seismic force before, during, and after earthquakes. The monitoring sensors needed to be integrated into a dampener that would be attached to the structural tower.

The solution allows the company to monitor force from emitted data to cross-reference the standard traffic force with the seismic force to understand its effect on the bridge. Its purpose is to help with predictive maintenance and influence future bridge designs to better compensate for the forces of an earthquake or other natural disasters, which are common in this part of the world.

READ THE SEISMIC BRIDGE MONITORING APPLICATION NOTE HERE

READ THE INFRASTRUCTURE CASE STUDY HERE

The project required a custom product that could handle the inimitable and considerable force of a bridge under every scenario of distress. Engineers developed a custom load pin to handle the force of movement in the bridge in the event of an earthquake. This load pin was much larger than our standard version and is rated at 900,000 lbf. The large load pins were designed to be integrated into the dampener with wireless data acquisition modules connected to the load pins to allow for remote access to the data. With the integration of Interface’s custom load pins and data acquisition module, the customer was always able to continuously collect data for real-time evaluation. The sturdy construction of our load pins and 900,000 lbf rating allowed for readings during all degrees of seismic activity.

To learn more about our wide variety of load pins and there many applications, please contact our application specialists today.

Load Cell Test Protocols and Calibrations

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In the Interface Load Cell Field Guide, our engineers and product design experts detail important troubleshooting tips and best practices to help test and measurement professionals understand the intricacies of load cells and applications for force measurement devices. In this post, our team has outlined some helpful advice for testing protocols, error sourcing and calibrations.

The first step in creating test protocols and calibration use cases is to define the mode you are testing. Load cells are routinely conditioned in either tension or compression mode and then calibrated. If a calibration in the opposite mode is also required, the cell is first conditioned in that mode prior to the second calibration. The calibration data reflects the operation of the cell only when it is conditioned in the mode in question.

For this reason, it is important that the test protocol, which is the sequence of the load applications, must be planned before any determination of possible error sources can begin. In most instances, a specification of acceptance must be devised to ensure that the requirements of the load cell user are met.

Typical error sources in force test and measurement are usually identified as being related to:

  • Lack of protocol
  • Replication of actual use case
  • Conditioning
  • Alignment
  • Adapters
  • Cables
  • Instrumentation
  • Threads and loading
  • Temperature
  • Excitation voltage
  • Bolting
  • Materials

In very stringent applications, users generally can correct test data for nonlinearity of the load cell, removing a substantial amount of the total error.  If this can’t be done, nonlinearity will be part of the error budget.

An error budget is the maximum amount of time that a technical system can fail without service level consequences. In force test and measurement, it is sometimes referred to as uncertainty budget.

Nonlinearity is the algebraic difference between output at a specific load and the corresponding point on the straight line drawn between minimum load and maximum load.

Nonrepeatability is essentially a function of the resolution and stability of the signal conditioning electronics.  Load cells typically have nonrepeatability that is better than the load frames, fixtures and electronics used to measure it.

Nonrepeatabillty is the maximum difference between output readings for repeating loading under identical loading and environmental conditions.

The remaining source of error, hysteresis, is highly dependent on the load sequence test protocol.  It is possible to optimize the test protocol in most cases, to minimize the introduction of unwanted hysteresis into the measurements.

Hysteresis is the algebraic differences between output at a given load descending from maximum load and output at the same load ascending from minimum load.

There are cases when users are constrained, either by requirement or product specification, to operate a load cell in an undefined way that will result in unknown hysteresis effects. In such instances, the user will have to accept the worst-case hysteresis as an operating specification.

Some load cells must be operated in both tension and compression mode during their normal use cycle, without the ability to recondition the cell before changing modes. This results in a condition called toggle, a non-return to zero after looping through both modes. The magnitude of toggle is a broad range. There are several solutions to the toggle problem, including using a higher capacity load cell so that it can operate over a smaller range of its capacity, use a cell made from a lower toggle material or require a tighter specification.

ONLINE RESOURCE: INTERFACE TECHNICAL INFORMATION

For questions about testing protocols, conditioning, or calibration, contact our technical experts. If you need calibration services, we are here and ready to help.  Click here to request a calibration or repair service today.

Load Button Load Cells 101

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Manufactured devices, technology advancements and product designs are getting smaller and smaller as innovations demand less space to do more for their consumers. As engineers are designing products with miniaturized components, they also need high quality test and measurement solutions that produce accurate results within these smaller testing spaces.

Interface has created a series Load Button Load Cells to meet these exact requirements. These load buttons are designed and manufactured to specifically fit into small and confined spaces, providing the precision-based measurements as expected from larger load cells.

Interface Load Button Load Cells are compact strain gauge-based sensors used in a wide variety of applications, including test and measurement and for general measurement applications. Interface standard LBM and LBS Load Button Load Cells can fulfill the need for compression force measurements at a very respectable precision level for most applications.

Product diameters range from 1 inch to 3 inches, with heights from 0.39 inch to 1.5 inches. The shaped load button load cell has a spherical radius to help confine misaligned loads to the primary axis of the cell. And while these products are small, they are capable of measuring compression forces from 10 lbf all the way to 50,000 lbf. The spherical radius of our Load Cell Load Buttons also help to confine misaligned loads to the primary axis of the cell.

Interface Load Button Load Cells 

Interface’s Custom Solutions Team and Product Engineers can also help to design a specific size and capacity to fit our customer’s exact requirements. Let us know what you need by contacting us here.

Load Button Load Cells Functionality and Proper Use

Applications that use compression loads on load button load cells requires an understanding of the distribution of forces between surfaces of various shapes and finishes.

The first and most important rule is to always avoid applying a compression load flat-to-flat from a plate to the top surface of a load button hub. The reason for this is simple, it’s impossible to maintain two surfaces parallel enough to guarantee that the force will end up being centered on the primary axis of the load button load cell. Any slight misalignment, even by a few micro-inches, could move the contact point off to one edge of a hub, thus inducing a large moment into the measurement.

Minor misalignments merely shift the contact point slightly off the centerline. In addition to compensating for misalignment, the use of a load button load cell of the correct spherical radius is necessary to confine the stresses at the contact point within the limits of the materials. Generally, load button load cells and bearing plates are made from hardened tool steel, and the contacting surfaces are ground to a finish of 32µ inch RMS. If you use too small of a radius it will cause a failure of the material at the contact point, and a rough finish will result in galling and wear of the loading surfaces.

Interface Load Button Load Cells in the Real World 

The evolving world of technology and product design has created a high demand for these types of small and accurate testing equipment. Innovative industries are looking at new ways to fit more capabilities into a single device that is the same size or even smaller. OEM applications that require this type of testing equipment include medical devices, drones, industrial automation, packaging and robotics.

We have highlighted a few examples of how Interface Load Button Load Cells have been used in the medical industry to solve complex challenges related to measuring compression force in confined spaces.

Measuring Vascular Clamp Force

A customer in the medical industry wanted to test various types of vascular clamps to see which type would generate the best clamping force for surgery. Using a Model LBS Load Cell, the clamps were secured onto the compression button. A Model 9330 High Speed Data Logging Indicator provided compression force measurements and allowed the customer to determine the most appropriate clamp type. Read the full application use case here.

Optimizing Surgical Stapler Force

Another customer needed to optimize the design of their surgical stapler to make it easier and more efficient for a medical professional to use. The original equipment manufacturer mounted the surgical stapler onto a test rig to enable force verification, and then connected a Model LBMU Compression Load Cell Button to a Model 9890 Load Cell Indicator. The indicator would collect compression force data from the stapler, and that data was then analyzed to allow the OEM to determine the design changes needed to reduce the amount of force applied to use the stapler.  Learn more about this application here.

For more information on our expanding lineup of Load Button Load Cells, see the overview below. In addition, say tuned in to the IQ Blog for an exciting announcement about new Interface Load Button Load Cell technology.  Most standard Load Button Load Cells are available to ship within 2 business days. Contact us for more information or visit our QS48 now.

Click here to see the full line of Load Button Load Cells.  

Strain Gages 101

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A strain gage is a sensor that varies its resistance as it’s stretched or compressed. When tension or compression is applied, the strain gage converts force, pressure, and weight into a change that can then be measured in the electrical resistance.

At the heart and soul of every load cell is a strain gage. This is the pinnacle technology that allows engineers to collect and analyze force data. In the industry, it is known as force measurement.

Strain gages are made through a photo-etch process using a flexible backing and a very thin foil. The way a strain gage works is when the backing and foil stretches or compresses, resistance goes up and down respectively. We know this as force. Think of stretching like a three-lane highway switching to two lanes, and vice versa for compression with two lanes going into three. As the load cell’s internal strain gage experiences force, it sends a signal with a precise measurement of the amount of force it’s experiencing.

There are many different types of strain gages for a variety of environments and force measurement needs. The major difference in strain gages is the base material used in the manufacturing process. Different materials are used when a load cell needs to perform optimally in a variety of temperatures, humidity levels, and elevations. Matching the correct strain gage and a load cell to the customer’s needs is critical to accuracy.

“Here at Interface, we pride ourselves on developing the most accurate force measurement tools, and it starts with our proprietary manufacturing of the strain gage.”  Scott Dunne, Production Engineering Manager

More than 52 years ago, when our founder Richard F. Caris started Interface, he purchased over a mile of foil, which is the base material used in strain gages. Caris understood the only way to ensure Interface customers received quality results from their force measurement products was to control every aspect of engineering design, product development, and production.

The key ingredient to our precision accuracy and reliability is the fact that we have vertically integrated the entire manufacturing process from design to production and have a deep understanding of the materials necessary to suit every client’s need for optimal results

Many load cell makers purchase their strain gages from a third party. This means there’s more variability in their manufacturing process and you often find the variances in their materials clash and diminish the accuracy, or they are not correctly suited for the customer’s project requirements.  Interface makes all their own strain gages.

We have learned everything there is to know about strain gage manufacturing and can guarantee the quality of our load cells in any environment based on this tenured expertise and having manufactured and calibrated hundreds of thousands (ok, millions) of force measurement devices. And here’s a fun fact, although we’ve manufactured hundreds of thousands of load cells and strain gages, we haven’t even used half of the original mile of foil we purchased in 1968. Good product managed well can go a long way!

For more information on Interface’s commitment to accuracy and reliability, we have written The Load Cell Field Guide, the definitive resource on load cells. It is available on Amazon. You can also download our latest technical white paper, Contributing Factors to Load Cell Accuracy, for free by clicking here.

Contributor:  Scott Dunne, Production Engineering Manager, Interface

Compression Force Testing 101

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Compression is a type of force that we apply every day often without thinking and compression is intensely tested in many of the products we use on a daily basis.

Compression force is defined as the energy generated from compressing an object or substance. Compressive force is simply the direction of the force applied to the load cell. The compressive strength of materials and structures is an incredibly important engineering consideration in both designs and build.

Whether you are clicking the keys on your laptop at work or slamming on your brakes to avoid an accident on your morning commute, you are using the compression force. Testing of the compression force is essential in developing a reliable and sturdy product that can withstand the pressure applied to it many times over. Often, safety is at the core of compression testing.

Load cells incorporated into the testing process work by measuring the pushing force of an application on a single axis. The strain gage compresses to measure the load applied. The deformation of the strain gage provides the measurement data. Application tests measure the total compression force the products or structures can handle, as well as the effects of compression over time through stress tests. In both cases, original equipment manufacturers (OEMs) need accurate measurements to guarantee their products can withstand compression in the short and long-term.

Interface supplies a variety of compression-focused load cells and accessories for all types of applications, both for test and measurement, as well as for inclusion in originally manufactured products and solutions. These compression load cells are often used in vehicles, industrial automation, aerospace, and defense industries. Applications are wide-ranging, from testing the impact of drones dropping packages to the material strength of bridges during an earthquake. Interface load cells are highly-rated to provide the most accurate data and reliability over time, which is why engineers rely on Interface compression-only load cells.

Here are a few of the compression load cells available from Interface:

1601 Gold Standard® Calibration Compression-Only LowProfile® Load Cells – Interface’s Gold Standard® Load Cells are designed for calibrating other load cells. The 1601 load cell is compression-only and has options available for a second and third bridge and overload protection.

1201 Compression-Only Standard Precision LowProfile® Load Cells – The Interface 1201 LowProfile® load cell provides a “compression-only” force measurement. Its spherical-shaped top surface helps provide minimal off-axis loading. 1201 is our most popular load cell designed for static applications and has a higher output than most competitive load cells.

2101 Dual Range Standard Compression-Only Load Cells – The Interface Model 2101 consists of lower and higher capacity model 1200 type load cells which are stacked with overload protection built into the lower capacity load cell permitting the high resolution to be obtained at both low and high levels of capacity. The Model 1201 is LowProfile® moment compensated.

LBM Compression Load Button Load Cells – The Interface LBM Compression Load Button is constructed from stainless steel and has a small size for all types of sensor apps and testing. This product is available in capacities that range from 25 lbf up to 50K lbf.

There is a variety of other standard compression-only load cells, including modified and custom Interface compression testing options in multiple capacities. For more information on our compression-only products or any of Interface’s industry-leading force measurement solutions, contact our Application Engineers.