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Any physical manufactured product is made of something—its fundamental material is the baseline on which its functionality and usefulness are built. Neglecting materials testing can be the root cause of final product failure in service and damage a brand’s profitability and reputation. Quality materials are the route to quality products.

For a product to be fit-for-purpose and meet legislative and commercial requirements it must check several boxes:

  • Strength—for resilience and durability in its lifetime of service
  • Flexibility—elasticity and recovery to bend and not break
  • Weight—lightness is the influential side effect of an optimized design
  • Manufacturability—forming and finishing to produce the physical item
  • Sustainability—recyclability, eco-design, sustainable materials and lean manufacturing are rapidly evolving drivers
  • Compliance – regulations, standards, and specifications to ensure safety, functionality, and adherence to legal and environmental requirements
  • Internal standards—a brand’s ISP, innovation and the desire to make a market-leading, customer-pleasing product should not get lost in the legislation
  • Functionality—ultimately the product must do what it claims to do on its delivery packaging

These universal, varied and potentially conflicting quality challenges are all able to be benchmarked by calculating the physical properties of raw materials and measurable attributes of a final product or component. Manufacturers use the aptly named universal testing machine to do just that, i.e., all the above.

Forcing The Issue

By testing the object in a controlled physical simulation of its force loading in use, manufacturers can be confident in meeting the ultimate goal of functionality. It is usually not possible to influence these loads— the forces a multi-ton truck’s suspension must withstand, the pressures (and vacuums) a spacecraft must resist, and the treatment a child’s toy must endure—but the ability to replicate the conditions consistently enables raw materials and final product design to be optimized.

Fundamental materials testing is performed to calculate a wide range of physical properties, including but certainly not limited to:

  • Tensile strength
  • Compressive strength
  • Bend strength
  • Elongation
  • Elastic limit
  • Young’s Modulus

These scientific terms quantify how we can compare raw materials between batches of the same type, for QC purposes, or between different types with a view to replacing one with another—better—alternative.

Essential product testing is performed to measure the object’s behavior under the application of loading specific to its intended purpose.

  • Pull-out resistance of a fastener
  • Crush resistance of a packaging box
  • Flexure of a golf club shaft
  • Extensibility of a rubber hose
  • Stretch of a textile
  • Elasticity of a suspension bridge cable

Materials testing is often destructive as we wish to know the ultimate bounds of its capabilities. Product testing may also be destructive but is often nondestructive when measuring how well it performs when being used for its intended purpose.

Material test specimens are loaded in tension, compression or bending to expose their properties in a repeatable and focused manner. By gripping the specimen in a certain way, we can control the stresses (loads) and strains (deformations) to be plugged into the mathematical formulae and return the numbers we require.

Tensile Testing

QM 1123 FEAT Test and Inspection Omnitest 5 extensometer
Loading a standard-shaped dumbbell test specimen under tension to pull it apart, potentially until break, to indicate its stress (Force per Area) and strain (Change in Length) behavior is a fundamental materials test. The curve shows one typical resulting graph and the initial slope where the material acts ‘elastically’ (i.e., can recover if released) is used to calculate Young’s Modulus. UTM force testing software should include these calculations.

Compressive Testing

QM 1123 FEAT Test and Inspection Compression test packaging and rice
Product compression testing has a diverse range of applications. Crush resistance of packaging is used to evaluate how it should be packaged itself when being transported or stacked. Lightweighting or switching to more sustainable alternatives forces manufacturers to re-evaluate raw materials and functional design to meet the same demands. Food products in bulk act as a homogenous material mass with individual particles behaving in a certain way when forced to break down under certain loads—not dissimilar to the internal structure of engineering materials. The ‘mouthfeel’ texture of foodstuffs, e.g., rice, is determined with a multi-blade compression/shear fixture that simulates biting and calculates hardness, stickiness and chewiness to specify cooking instructions or optimize harvesting strategies. A UTM with software capable of Texture Profile Analysis (TPA) formalizes these tests.

Flexure Testing

QM 1123 FEAT Test and Inspection Deflectometer twin column 50kN touch
UTM software and connected deflectometer instrumentation can apply bending to a structure-reinforcing rebar and measure deflection directly on the test piece in the axis of deformation, vital for accurate calculation of material properties. The test frame can accommodate loadcells rated at any value below its capacity. This enables high force / small deformation applications to be performed on the same machine as low force / high deformation applications, which may take advantage of the larger test space available. Where temperature is a critical environmental condition, larger UTMs can support temperature chambers in which this is controlled.

Everything Everywhere All At Once, Digitally

We have seen how a software-controlled universal testing machine is the golden bullet for applying stress, strain and a multitude of other loading conditions on the sample in question. Standard geometry test pieces are used for raw materials work to ensure accurate like-for-like comparisons. For industry-specific product samples, industry-specific fixturing is employed to hold and deform them as appropriate for the loading conditions it will experience in the field.

The software enables complex programs to be built and so precisely controls how the sample is loaded. It also collects the relevant data and automatically performs any calculations—immediately returning the results, as graphs, tables, or a straightforward Pass/Fail. In recent years, the digital revolution has hit the wider manufacturing world—manufacturing 4.0 is well underway—and the advances in implementing the secure handling of data has allowed the policies and process once reserved for the materials science lab to be leveraged elsewhere. Today’s UTM software must be built on architecture and have the connectivity to add value to global companies. Storage, sharing and recall of the data—programs and results—enable the same, consistent implementation of tests across sites, with traceability that is essential in the pharmaceutical and medical industries.

Back To Basics

A final product or component may require modification or replacement for any number of reasons—legislative changes, feedback from maintenance and repair issues, the desire to improve features and functionality. Any one of these triggers may necessitate substitution of raw materials. Organizations with quality assurance capabilities that include materials testing UTM equipment can be responsive by implementing the same test routines to ensure the new product confidently matches or exceeds its predecessor.