Composite materials have clear benefits for manufactured parts in aerospace, medical, automotive applications and many other industries. Ensuring the highest part accuracy is critical. Force measurement and material testing are essential processes for product designers and manufacturers to gain insightful data to create high-quality composite components.
As consumers, we apply a certain amount of force to complete everyday tasks. Even simple motions, such as turning a key or operating a remote control, requires a specific amount of applied force. Whether to accommodate human ergonomics or to meet product safety regulations, manufacturers apply force measurement processes for every product they design.
Polymer composites in particular are changing the way composites are used. They have a high strength-to-weight ratio and are relatively easy and inexpensive to manufacture.
To ensure polymer composites can withstand expected force, product designers and OEMs determine if the material will stretch or elongate and identify its exact breaking point. The major objective of any test and measurement process is to build a coherent set of materials data, but for composite materials, one size rarely fits all.
For example, composites data are likely to be unique to each sector, product, and application. The most common tests for tensile strength (MPa or PSI) are tensile chord modulus of elasticity (MPa or PSI), tensile strain (%), Poisson’s ratio and transition strain (%). However, when testing composites, the application should not presuppose any prior knowledge of required measurements.
Using Starrett L3 software as an example, rather than providing preset data, the user creates a test method for the specific material. The product designer or OEM can then easily analyze the stress, strain, load, distance and time for each material, with measurements displayed on graphs and data tables with statistics and tolerances. Tests can use tension, compression, flexural, cyclic, sheer and frictional forces.
The unfamiliarity of composite materials requires mechanical testing throughout the entire design and production process. Consequently, automation is attractive to manufacturers eager to reap the rewards of composite materials.
Automated software packages should be capable of creating an interface that links hardware and software to improve processes. For force measurement software applications, programming experience should be optional, not essential, as with easy-to-use software, such as from Starrett.
By exporting measurement data through a USB or wirelessly, manufacturers can access high-resolution graphs based on load, distance, height and time of the measurement. In addition, a Starrett L2 plus system archives historical test data, making it available for analysis at a later date and helping to speed future tests and navigate potential problems or errors. This intelligent software increases the accuracy of force measurement while also improving precision.
As some composites are not yet fully scalable materials and mass manufacturing data are not readily available, testing and measurement will play a major role in the research that creates data.
James M. Clinton is product manager for force and material test products, L.S. Starrett Co.