Understanding the Challenges and Solutions When Measuring Small Forces

Measuring small forces accurately can be a significant challenge for calibration labs, researchers, and engineers

Published: Tuesday, March 14, 2023 - 12:03

Small-force measurement is crucial for many applications, such as testing materials, monitoring biomedical devices, and studying the behavior of cells and molecules. In this article, we’ll explore the challenges of measuring small forces and the solutions that are available to address them.

There are several challenges to measuring small forces:
1. Sensitivity: Measuring small forces requires high-sensitivity instruments that are capable of detecting very small changes in force. However, these instruments can also be affected by environmental factors, such as temperature and vibrations, which can result in measurement errors.
2. Dynamic range: The dynamic range of a measuring instrument refers to the range of forces that can be measured accurately.
3. Signal-to-noise ratio: The signal-to-noise ratio refers to the ratio of the desired signal to the unwanted noise that is present in the measurement. Measuring small forces often requires a high signal-to-noise ratio, but this can be difficult to achieve with traditional instruments.
4. Controlling the forces: Having a control system to control the force, so as not to overload the force-measuring device.

There are several solutions for measuring small forces, including:
1. Nanotechnology-based instruments, such as atomic force microscopes (AFMs) and nanoindenters, are designed specifically for measuring small forces. These instruments use a fine probe to apply a force to the sample and measure the resulting deformation.
2. Piezoelectric sensors use the piezoelectric effect to convert mechanical strain into electrical signals. They are highly sensitive and can be used to measure very small forces.
3. Microelectromechanical systems (MEMS) are small mechanical devices that can be integrated into electronic systems. They are capable of measuring small forces and are often used in microscale applications.
4. Force transducers such as Morehouse Miniature S-Type Load Cells are capable of measuring small forces from 0.1 pound of force (lbf) through 50 lbf. These load cells offer overload protection of 10x on capacities up to 10 lbf, and 1.5x protection on other capacities.

Morehouse miniature S-type load cells from 1 lbf to 50 lbf are critical when a small-size load cell with high accuracy and low measurement risk is needed. Based on measured performance, these load cells represent a high standard for miniature S-type load cells with the industry’s lowest range of use, obtaining ASTM E74 Class A-verified range of forces from 5 percent of capacity.

These compression- and tension-type miniature S-type load cells are often the choice for companies that want the lowest possible uncertainties at an affordable price. The Morehouse miniature S-type load cells cost significantly less than other manufacturers’ similar products.

The lower uncertainties allow for shorter setup times, less frequent standard changes, and fewer standards to maintain.

Miniature S-type load cells are suitable for the following uses:
• Field use where space is at a minimum
• Environments that require durable construction, such as force measurement and robotics
• ASTM E74 performance: Lower limit factor (LLF) better than 0.0125 percent, Class A better than 5 percent of capacity using ascending calibration data
• Calibration of small-force equipment
• Applications requiring small forces with extremely high overload protection (10x up to 10 lbf capacities, 1.5x on 20 lbf+ capacities)
• Direct reading applications where an accuracy of better than 0.1 percent is required

If Morehouse S-type miniature load cells don’t meet your needs, Morehouse offers multiple load cell options, most of which can be readily customized to meet customers’ unique requirements.

Summary

Measuring small forces accurately can be a significant challenge, but advances in technology have provided solutions that make it possible. Whether you’re working in a laboratory, an industrial setting, or in the field, understanding the challenges and solutions of small-force measurement is essential for achieving accurate and reliable results. Morehouse S-Type load cells can provide a solution for accurately measuring force from 0.1 lbf through 50 lbf.

Morehouse clarifies complex topics and provides tools such as free guidance documents, Excel sheets, and products to help you make better force measurements. Our mission is to ensure that quality personnel have the resources to make the right decisions about the load cell they purchase.

Everything we do and provide is designed to change how people think about force and torque calibration. We challenge the “just calibrate it,” or even worse, “just sticker it” mentality by educating our customers on what’s important and why it matters, what causes significant errors, and how to focus on reducing them. In addition, Morehouse makes simple-to-use force calibration products, building excellent force equipment with the key tenets of plumb, level, square, rigid, and torsion-free frames.

About The Author

Henry Zumbrun

Henry Zumbrun is president of Morehouse Instrument Co. where he has managed the force and torque calibration lab and services in the family-owned business since the 1990s. Morehouse helps labs lower their force measurement uncertainties and torque, resulting in more-accurate measurements, which lowers costs, reduces risk, and increases quality. Morehouse designs and manufactures products in line with customer requirements, lean, Six Sigma, and best practices guidelines.He has taught various classes and sessions at NCSLI, MSC, A2LA, etc., authored several published papers, written a book titled “Force Calibration for Technicians and Quality Managers: Top Conditions, Methods, and Systems that Impact Force Calibration Results,” and was the primary Author on the “G126 - Guidance on Uncertainty Budgets for Force Measuring Devices” for A2LA. He has been part of the ASTM E28 committee for well over a decade and has made several contributions to the ASTM E74 and E2428 standards through the committee.