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Interface Mini Load Cells Growing in Product Use and Testing

One of the biggest manufacturing trends over the past decade is the miniaturization of hardware components. Reducing the size and weight of products and the components, while increasing the power of complex technology systems, is growing in use across all industry segments using force measurement in design and production.

The growing trend to utilize sensor technology in miniaturized products has been especially significant in the medical, consumer products, technology and robotics industries. These industries are looking to fit more force and measurement capabilities into a package that is the same size, or in many cases, considerably smaller than previous generations of like products.

To address this expanding trend, Interface Mini™ Load Cells were designed specifically for light touch, light weight, high accuracy, and robust performance to utilize for OEM products and smaller testing applications in confined spaces. Our miniature load cells provide exceedingly accurate measurements, similar to our full-size load cells and utilize our proprietary alloy strain gages. Capacities are available as low as 0.11 lbf / 0.5 N and as high as 100 kN.

These small-scale load cells are engineered and manufactured to provide extremely accurate output data with the same degree of precision performance as our standard load cells. OEM’s must have this sort of precision force technology because many of the devices being made today are minuscule and more complex in comparison to earlier products and testing application use cases.

In the medical device industry, innovative and often small new products are used in various life-saving applications. Any inaccuracy or miscalculation of force can have devastating effects. Take a look at how our Interface LBS Miniature Compression Load Button Load Cell and 9330 High Speed Data Logging Indicator were used to record the force measurements when designing and testing vascular clamp surgical devices. You can also read about the Vascular Clamp application note here.

In our earlier Mini Load Cells 101 blog, we discussed the features and benefits of Mini Load Cells in detail. Today, we are highlighting some of our best-selling and new Mini Load Cell solutions available from Interface.

QS48 TruckSpecial Note: A large variety of our standard miniature load cells are available today through our QS48 e-commerce site for easy online ordering. Click here to order now through our QuickShip program and get your mini’s in as little as 48 hours! If you need something specifically customized, reach out to our expert application engineers who can work with you to design custom miniature load cells that will fit your exact requirements.

INTERFACE MINI™ LOAD CELLS

MB Miniature Beam Load Cell

Model MB is a miniature beam load cell used in medical test machines and a variety of low capacity applications. Performance on this product is +/- 0.03% FS and available capacities are 5 to 250 lbf (22.2 N to 1.11 kN).

Product Features:

  • Proprietary Interface temperature compensated strain gages
  • Performance to 0.03%
  • Low height – 1-inch max
  • Eccentric load compensated
  • ±0.0008% /˚F – max temperature effect on output
  • Low deflection

MBP Overload Protected Miniature Beam Load Cell

Model MBP series load cells provide similar performance to Model MB series with the added safeguard of internal overload protection. This patented overload protection is accomplished via hard stops that are EDM machined into the load cell flexure. This provides greater overload protection (2.5-10lbf ±1000% of full-scale capacity, 100 N ±500% of full-scale capacity), giving the user added protection in more severe applications.

Product Features:

  • Proprietary Interface temperature compensated strain gages
  • 10x overload protection
  • Low height – 1in max
  • 0.0008%F temp. effect on output
  • 5′ Integral Cable (custom lengths available upon request)
  • NIST Traceable Calibration Certificate

WMC Sealed Stainless Steel Miniature Load Cell

Interface Model WMC Stainless Steel Miniature Load Cell is excellent for industrial applications because of its stainless steel, sealed, environmentally protected construction. This product is available in capacities ranging from 5 to 500 lbf (22 to 2200 N).  Submersible versions of this product are available as well.

Product features:

  • Environmentally sealed tension and compression load cell
  • Proprietary Interface temperature compensated strain gages
  • Tension and compression
  • Small Size
  • Stainless Steel Construction
  • Submersible

SSM and SSM2 Sealed S-Type Load Cells

Model SSM is a moderately priced highly-accurate sealed load cell for test machines and other general purpose applications. This product is available in capacities ranging from 50 to 10K lbf (200 N to 50 kN).

Product Features:

  • Proprietary Interface temperature compensated strain gages
  • Environmentally sealed
  • 0.02% non-repeatability
  • 0.0008%/°F (0.0015%/°C) temp. effect on output
  • 0.025% creep
  • Tension and compression

LBM Compression Load Button Load Cell

Model LBM Compression Load Button is very popular.  It is constructed from stainless steel and has a small size. This product is available capacities range from 25 lbf up to 50K lbf.

Product Features:

  • Temperature compensated
  • Integral load button
  • Small diameter
  • Environmentally sealed
  • Stainless steel

LBS Miniature Load Button Load Cell

Model LBS Miniature Compression Load Button is constructed from stainless steel and has a small size. This product is available capacities range from 5 lbf up to 1K lbf (22.2 N to 4.45 kN).

Product Features:

  • Temperature compensated
  • Integral load button
  • Small diameter
  • From 0.12″ height

LWPF1 Press Force Load Washer Load Cell

Model LWPF1 Press Force Load Cell is one of several load washer load cells available from Interface. It features a large thru-hole and short overall height. This product is available in capacities ranging from 2 kN to 100 kN (450 to 22.5K lbf).

Product Features:

  • Short height
  • Large thru hole
  • For press-force monitoring

BPL Pedal Load Cell

BPL Pedal Load CellThe Model BPL is a very LowProfile® load cell is used for measuring force on brake pedals. Interface Model BPL has the lowest sensitivity to off-center loading available and will outperform any competitive model.

Product Features:

  • Lowest nonlinearity and hysteresis of any brake pedal load cell – < 0.05%
  • Ultra-low height
  • Low sensitivity to off-axis loads
  • Mounts directly to pedal with included strap(s)
  • Interchangeable mounting plates
  • For use with gas, brake or clutch pedal
  • Storage case included

There are more than 30 different Interface Mini Load Cells and sensors available, in addition to our ability to provide modified and custom Mini Load Cells solutions. To find the Interface Mini that works for your needs, or to learn more about our expanding lineup of load cells and torque transducers, please visit /products/.

Addressing Off-Axis Loads and Temperature Sensitive Applications

As technology progresses, one of the main differences we see over years and years of iteration on a wide range of consumer and commercial technology is miniaturization. There are hundreds of thousands of examples of advancing technology that went from the room-size of a mainframe decades ago, to a handheld device today. As technology grows more compact and convenient, the equipment used to design, test and manufacture these devices has to follow suit.

This is one of the driving factors for Interface to increase the product types and capabilities in our Load Button Load Cells and Interface Mini Load Cell products. Interface’s Load Button Load Cells are designed for customers who require the measurement of forces in a very confined space. They provide the most accuracy in as little space as possible. Diameters range from 1 inch to 3 inches, with heights from 0.39 inch to 1.5 inches.

For many years, load button load cells have been sensitive to off-axis, eccentric or misaligned loads. This means that if the load is not exactly perpendicular to the surface it’s resting on, the data could become skewed or inaccurate. All on-axis load generates some level, no matter how small, of off-axis extraneous components. This can cause a variety of challenges including slight inaccuracies and reduction of the load cells overload capacity.

With Interface’s family of load button load cells, we bring premium accuracy and repeatability, even under eccentric angular loading. The shaped load button has a spherical radius to help confine misaligned loads to the primary axis of the cell. Our design engineers and force measurement experts have purposefully tested applications under a wide variety of load conditions to ensure that the our load button series can continue to deliver premium performance. We have been extremely pleased with the results and continue to advance our offerings, including the soon to be released precision focused ConvexBT load button load cells.

The load button load cells’ size has in the past precluded the use of internal temperature compensation. We have redesigned our ultra precision product line of load buttons to ensure that this is no longer something the user has to account for when testing a product in certain environmental conditions.

Interface engineers have eliminated this issue by taking the technology out of the load button load cells cable and designing it back into the product. This ensures that temperature-sensitive applications do not suffer from errors caused by the load cell being exposed to different environmental conditions than the cable.

These new features open new possibilities to test compression force on a broader range of products and environments. To learn more about our ultra precision Load Cell Load Buttons and how it can make a difference in your design and testing process when dealing with tight and confined spaces, contact our Application Engineer experts here.

To see the complete line of Load Button Load Cells, visit here.  Watch for the release announcement of our new ultra precision ConvexBT product coming out this month.

Contributors:  James Richardson, Interface Mechanical Engineering Manager and Ted Larson, VP Product Management and Marketing

Source:  Interface Load Cell Field Guide

 

Load Button Load Cells 101

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.