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Advancing Load Button Load Cell Capabilities with ConvexBT

Demands for high precision testing utilized for compact designs and in confined spaces is growing. The requirements for quality, accuracy and most importantly reliability are what has driven the experienced engineers at Interface to create the newly released ConvexBT™ Load Button Load Cell product line.

The revolutionary design of the ConvexBT is a first of its kind load button load cell, providing better temperature resistance and more enhanced eccentric load rejection. Miniature load cells categorized as load buttons have been sensitive to off-axis, eccentric or misaligned loads. This means if the load is not exactly perpendicular to the surface it is resting on, the data could become skewed or inaccurate.

Interface designed the ConvexBT™ Load Button Load Cell to confine misaligned loads to the primary axis of the cell providing superior performance in comparison to similar products on the market in repeatability, better data and reproducible results.

As technology advances, there is a growing demand to make devices and products more compact and convenient. This trend is happening across industries and is especially prevalent in medical, industrial automation and products reliant on advanced communications technology. To design and validate these products, our customers need force-sensing solutions that can fit in confined spaces and provide extremely accurate data. This is the driving force behind the development of ConvexBT, the next generation in force measurement device.” – Ted Larson, VP product management and marketing, Interface.

CONVEXBT FEATURES AND SPECIFICATIONS

The newly released ConvexBT product comes in two different sizes: 3/8-inch, and 1/2-inch, which are all manufactured using 17-4 PH heat treated stainless steel. These options provide a wide measurement range from 10 to 250 lbf, a compensated temperature range of 60° to 160°F, and an operating temperature range of -40° to 175°F.

Additional specifications for ConvexBT include:

  • 2.00 ± 20% mV/V rated output
  • ± 0.25 non-linearity as a percentage of full scale
  • ± 0.25 hysteresis as a percentage of full scale
  • ± 0.50 static error band as a percentage of full scale

Other load cell load buttons designs have also been extremely sensitive to temperature conditions. Interface has redesigned its ConvexBT ultra-precision product line of load buttons to ensure that this is no longer something the user has to account for by taking the sensing technology disrupted by temperature out of the cable, and designing it directly into the load button.

The new available ConvexBT models include the following capacities:

  1. ConvexBT Model LBSU-10 lbs 3/8″
  2. ConvexBT Model LBSU-25 lbs 3/8″
  3. ConvexBT Model LBSU-50 lbs 3/8″
  4. ConvexBT Model LBSU-100 lbs 1/2″
  5. ConvexBT Model LBSU-250 lbs 1/2″

Additional model capacities will be available this year.  You can view the complete product specifications as well as technical guide by visiting the product page here.

ConvexBT was developed through a combination of intense research into growing technology trends in force measurement and actively collaborating with our customers to understand their unique challenges, By introducing the industry’s most advanced and versatile ultra-precision load button load cells, we are solving the test and measurement challenges associated with miniaturization of existing and new technologies.” – Greg Adams, CEO at Interface

The revolutionary ultra-precision line of ConvexBT™ Load Button Load Cells uniquely uses multi-point calibration for testing force on miniaturized products and within confined spaces where accuracy is paramount to success and safety. The requirements are critical to common buyers of miniature load cells, especially for use in medical devices, robotics and in industrial automation applications

In addition to its ability to solve test and measurement challenges with compact devices, another key benefit of ConvexBT is its versatility in that it can be used as a traditional test and measurement solution. It can also be installed into OEM components and devices as an advanced miniature sensing solution to collect accurate real-time force data on the product as it is in use.

ConvexBT is available now under the product family of Interface Mini® Load Cells. The product is part of a growing line of Interface Load Button Load Cells. The new ConvexBT model LBSU specifications are available here: /product-category/load-button-load-cells/.

Read more about Off-Axis Loads and Temperature Sensitive Applications here.

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