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Compression testing plays a crucial role in the packaging industry by providing a comprehensive assessment of a material’s ability to withstand external forces and pressures during handling, transportation, and storage. For this reason, understanding the operation of the compression testing machine and its advantages is highly important for a company.

What are Compression Tests?

Compression tests are a type of mechanical testing used to determine the behavior of materials when subjected to compressive forces. These tests are essential for understanding how a material responds to applied loads that tend to reduce its size or volume.

Compression testing helps assess the strength, stiffness, and deformation characteristics of materials under compression.

Types of compression testing

  • Uniaxial compression testing
    This is a compression test in which the compression forces are applied on a single axis, making it a perfect complement to the tension tests.
  • Fatigue testing
    Fatigue testing seeks to find the permanent change at the level of structure in a material after subjecting it to compressive forces in a progressive manner, which may fail.
  • Force deformation curve tests
    These tests are intended to define the elastic strength and plasticity of the material when subjected to compressive forces. Many materials present an elastic behavior before their deformation or rupture, defined by a linear relationship between the compressive force and the deformation. This means that the sample will start to deform when the compressive force is applied on the sides of the box, but will take its original shape and size when it is removed, as long as the point where the material exhibits plastic behavior is not reached. In this case, the box will deform or break without returning to its initial state.
  • Resistance verification tests
    These tests are used to test and compare the properties of materials against compressive forces. The information extracted about the strength of such materials is essential during the design or validation stage of Packaging.

Compression testing modes and their role in packaging optimization

In a compression test, the package is placed between the two plates of the compression tester, which distribute the applied force that pushes inward from opposite sides.

Different testing modes:

  • BCT (Box Compression Test) determination.
  • Creep characterization.
  • Apply and hold.
  • Apply and release.

BCT (Box Compression Test)

Box compression testing methods include the BCT (Box Compression Test), which consists of applying an increasing compression force to a load until failure.

Through this test, it is possible to obtain a force-deformation curve, thereby calculating the resistance of the package. This information allows for making decisions regarding the packaging (e.g., whether using a stronger one is necessary).

Apply and hold

In the press-and-hold test, forces are applied to the load, and the pressure is maintained for a certain duration. This test assesses the package’s resistance to sustained compression or pressure situations.

The press-and-hold test evaluates how well the package maintains its structural integrity under continuous compression. It provides insights into the long-term durability and stability of the packaging when subjected to prolonged pressure.

Apply and release

In this test, compression forces are applied to a load, and then they are released. The purpose of this test is to verify the resilience or resistance of a package. By subjecting the package to a temporary compression force and then releasing it, you can assess how well the package recovers from the compression.

This test helps determine if the packaging material and design can withstand external pressure and return to its original form after being compressed.

Creep characterization

The creep test, also known as a creep or time-dependent deformation test, assesses how materials deform over an extended period under a constant load. A representative sample of the material is subjected to a constant load, and the resulting deformation is continuously measured and recorded.

This test is crucial for understanding a material’s long-term stability and its ability to withstand sustained loads, providing valuable insights for applications such as material engineering, structural design, and product development.

Enhance packaging integrity: unlocking potential through compression testing machines

Investing in compression testing technologies is not just a precautionary measure but a smart strategy to ensure customer satisfaction and operational efficiency across the entire distribution chain. Here’s a brief overview of the importance of compression testing in packaging:

Product Integrity and Protection:

Compression testing helps ensure that packaging materials can withstand the weight and pressure exerted on them when stacked or stored in a warehouse or during transportation. This is critical for maintaining the integrity of the packaged products, especially for delicate or fragile items.

Stacking and Palletizing:

Many packaged goods are stored in warehouses or transported in stacked pallets. Compression testing helps determine how well packaging can withstand the load without deforming, collapsing, or compromising the products within. This is particularly important for optimizing storage space and ensuring efficient logistics.

Regulatory Compliance:

Regulatory bodies often set standards for packaging strength and performance to ensure the safety of products during handling and transportation. Compression testing is a key method for assessing compliance with these standards, helping manufacturers adhere to industry regulations.

Transportation Safety:

During transportation, packages are subjected to various external forces, including vibrations, shocks, and compressive loads. Compression testing helps in designing packaging that can withstand these conditions, reducing the risk of damage to the products and minimizing the potential for losses during transit.

Cost Optimization:

Understanding the compression strength of packaging materials allows manufacturers to optimize the use of materials. This can lead to cost savings by avoiding over-engineering or using more material than necessary while still meeting the required strength and durability criteria.

Retail Shelf Stability:

Products often spend time on retail shelves before being purchased. Packaging needs to withstand the pressures of stacking and handling in a retail environment. Compression testing helps in designing packaging that maintains its structural integrity and aesthetic appeal under these conditions.

Consumer Satisfaction:

Packaging that fails to protect its contents can lead to customer dissatisfaction. Compression testing helps manufacturers design packaging that meets the necessary strength requirements, ensuring that products reach consumers in optimal condition. This contributes to positive brand perception and customer loyalty.

Compression Testing Regulations

To successfully conduct compression tests, it’s crucial to have a compression machine that not only performs its task but also ensures compliance with the relevant regulations.

ASTM D642:

  • Standardized test method for determining compressive strength.
  • Applies to shipping containers, unit loads, and components.
  • Measures compressive strength of various packaging types.

  • Significant Tappi standard for packaging.
  • Measures the resistance of corrugated or solid fiber shipping containers to external compressive forces.
ISO 2872:

  • International standard specifying two methods for compressive testing of complete packages.
  • Can be a single test for deformation analysis or part of a sequence for assessing distribution cycle endurance.
ISO 13820:

  • Describes equipment specifications for compressive testing on materials like paper, cardboard, and corrugated fiberboard.
  • Two options for compression machines: one with fixed platforms applying forces at a constant rate and another with a deformable bar, where neither the rate nor the pressure is constant.

Safe Load Testing Technologies Solution: innPress Compression Testing Systems

innPress – Our Accurate and Reliable Compression Testers

Safe Load Testing Technologies presents the innPress family, featuring a diverse range of compression machine models meticulously crafted for performing compression tests and creep tests on shipping containers, pallets, and load units.

Amongst these innovations, we are thrilled to introduce a robust and versatile electric machine. This cutting-edge equipment offers precise compression testing with an adjustable stroke, facilitating on-site data collection.

Additionally, its advanced capabilities include automatic report generation, and streamlining the testing process for unparalleled efficiency and accuracy.

Find out more about how to ensure load stability in our free downloadable ebook Guide to Load Stability. And don’t hesitate to contact us if you need a compressometer or advice for your project.

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