The container compression test measures the

compressive strength In mechanics, compressive strength (or compression strength) is the capacity of a material or Structural system, structure to withstand Structural load, loads tending to reduce size (Compression (physics), compression). It is opposed to ''tensil ...

of packages such as boxes, drums, and cans. It usually provides a plot of deformation vs compressive

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

. It is commonly used to evaluate

shipping container A shipping container is a container with strength suitable to withstand shipment, storage, and handling. Shipping containers range from large reusable steel boxes used for intermodal shipments to the ubiquitous corrugated box design, corrugated b ...

s made of

corrugated fiberboard Corrugated fiberboard, corrugated cardboard, or corrugated is a type of packaging material consisting of a fluted corrugated sheet and one or two flat linerboards. It is made on "flute lamination machines" or "corrugators" and is used for maki ...

as well as

wooden box A wooden box is a container made of wood for storage or as a shipping container. Construction may include several types of wood; lumber (timber), plywood, engineered woods, etc. For some purposes, decorative woods are used. Boxes as shi ...

es and

crate A crate is a large shipping container, often made of wood, typically used to transport or store large, heavy items. Steel and aluminium crates are also used. Specialized crates were designed for specific products, and were often made to be reus ...

s. Industrial and consumer packages other than boxes can also be subjected to compression testing: drum, pail, bottle, tub etc. Package components are also evaluated for compression resistance. It is usually a laboratory test involving a special machine, a compression tester, to apply controlled compression on a test

specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository f ...

. A

universal testing machine A universal testing machine (UTM), also known as a universal tester, universal tensile machine, materials testing machine, materials test frame, is used to test the tensile strength (pulling) and compressive strength (pushing), flexural stren ...

is sometimes configured to perform a package compression test. Compression testing can also involve a superimposed ''dead load'' to a test package.

Test procedures

A common method of conducting the test, as described in several published standard

test method A test method is a method for a test in science or engineering, such as a physical test, chemical test, or statistical test. It is a specified procedure that produces a test result. To ensure accurate and relevant results, a test method should b ...

s, is to compress a box at a constant rate of between two rigid platens. The platens can be fixed so that they remain parallel or one can be pivoted or "floating". The test can be conducted on empty or filled boxes, with or without a box closure. Conditioning to standard temperature and humidity is important. The results of the constant rate of compression test can be: * The peak load * The deformation at peak load * The load at a critical deformation (head space, etc.) * The ability of a container to protect the contents from compression damage * etc. The dynamic loads have some relationship with expected field loads.: often factors of 4 or 5 are used to estimate the allowable working load on boxes. A test can also be conducted with platens that are not mechanically driven but are free to move with a fixed mass (or fixed force) loaded upon them. The results of static load testing can be: * The time to failure * The time to a critical deformation * The ability of a container to protect the contents from compression damage * etc. As with any laboratory testing field validation is necessary to determine suitability.

Corrugated box testing

Corrugated shipping containers are exposed to compression hazards during storage and shipment. Proper compression strength is a key performance factor.

Factors potentially affecting test results

* Size and construction of the specific shipping container under test * Grade and flute structure of

Moisture content Water content or moisture content is the quantity of water contained in a material, such as soil (called ''soil moisture''), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed ...

of the corrugated board (based on

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...

) * Orientation of the box during the test * Inner supports, if used during testing (wood, corrugated board, cushioning) * Contents (when box is tested with contents) * Box closure * Whether the compression machine has "fixed" or "floating" (swiveled) platens. * Previous handling or testing of box *Vent and hand holes * etc.

Estimations

Corrugated fiberboard can be evaluated by many material test methods including an Edge Crush Test (ECT). There have been efforts to estimate the peak compression strength of a box (usually empty, regular singelwall slotted containers, top-to-bottom) based on various board properties. Some have involved

finite element analysis Finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical models, mathematical modeling. Typical problem areas of interest include the traditional fields of structural ...

. One of the commonly referenced

empirical Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law. There is no general agreement on how t ...

estimations was published by McKee in 1963. This used the board ECT, the MD and CD flexural stiffness, the box perimeter, and the box depth. Simplifications have used a formula involving the board ECT, the board thickness, and the box perimeter. Most estimations do not relate well to other box orientations, box styles, or to filled boxes.

Physical test A physical test is a qualitative or quantitative procedure that consists of determination of one or more characteristics of a given product, process or service according to a specified procedure.ASTM E 1301, Standard Guide for Proficiency Testing ...

ing of filled and closed boxes remains necessary.

Calculating compression requirement

Fiber Box Association have a method for calculating the required compression losses which includes the following factors: * Time * Moisture * Palletizing type * Pallet patterns * Pallet type * Handling

Dynamic compression

Containers can be subjected to compression forces that involve distribution dynamics. For example, a package may be impacted by an object being dropped onto it (vertical load) or impacted by freight sliding into it (horizontal load). Vehicle vibration can involve a stack of containers and create dynamic compression responses.

Package testing Package testing or packaging testing involves the measurement of a characteristic or property involved with packaging. This includes packaging materials, packaging components, primary packages, shipping containers, and unit loads, as well as th ...

methods are available to evaluate these compression dynamics.

References

Relevant Standards

ASTM ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and s ...

Standard D642 Test Method for Determining Compressive Resistance of Shipping Containers, Components, and Unit Loads. *

Standard D4577 Test Method for Compression Resistance of a Container Under Constant Load *

Standard D7030 Test Method for Short Term Creep Performance of Corrugated Fiberboard Containers Under Constant Load Using a Compression Test Machine *German Standard

DIN DIN or Din or din may refer to: People and language * Din (name), people with the name * Dīn, an Arabic word with three general senses: judgment, custom, and religion from which the name originates * Dinka language (ISO 639 code: din), spoken ...

55440-1 Packaging Test; compression test; test with a constant conveyance-speed *

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

12048 Packaging—Complete, filled transport packages—Compression and stacking tests using a compression tester

External links

* Package Compression Testin

{{packaging Paper products Packaging materials Containers