The container compression test measures the compressive strength of packages such as boxes, drums, and cans. It usually provides a plot of deformation vs compressive force.
It is commonly used to evaluate shipping containers made of corrugated fiberboard as well as wooden boxes and crates. Industrial and consumer packages other than boxes can also be subjected to compression testing: drum, pail, bottle, tub [1] etc. Package components are also evaluated for compression resistance. [2]
It is usually a laboratory test involving a special machine, a compression tester, to apply controlled compression on a test specimen. A universal testing machine is sometimes configured to perform a package compression test. Compression testing can also involve a superimposed dead load to a test package.
A common method of conducting the test, as described in several published standard test methods, is to compress a box at a constant rate of 1⁄2 inch per minute (13 mm/min) 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 dynamic loads have some relationship with expected field loads.: [3] 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. [4] The results of static load testing can be:
As with any laboratory testing field validation is necessary to determine suitability.
Corrugated shipping containers are exposed to compression hazards during storage and shipment. Proper compression strength is a key performance factor.
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. [11] One of the commonly referenced empirical estimations was published by McKee in 1963. [12] 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 testing of filled and closed boxes remains necessary.
Fiber Box Association have a method for calculating the required compression losses which includes the following factors:
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. [13] Package testing methods are available to evaluate these compression dynamics.
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 making corrugated boxes. The corrugated medium sheet and the linerboard(s) are made of kraft containerboard, a paperboard material usually over 0.25 millimetres (0.01 in) thick.
Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging can be described as a coordinated system of preparing goods for transport, warehousing, logistics, sale, and end use. Packaging contains, protects, preserves, transports, informs, and sells. In many countries it is fully integrated into government, business, institutional, industrial, and for personal use.
A pallet is a flat transport structure, which supports goods in a stable fashion while being lifted by a forklift, a pallet jack, a front loader, a jacking device, or an erect crane. Many pallets can handle a load of 1,000 kg (2,200 lb). While most pallets are wooden, pallets can also be made of plastic, metal, paper, and recycled materials.
A Slip sheet is “a corrugated, solid fiber, or plastic sheet onto which a unit load can be assembled. A protruding short panel can be grasped by the jaws of a pull-pack truck and the load pulled back onto the pull-pack platform.”
Strapping, also known as bundling and banding, is the process of applying a strap to an item to combine, stabilize, hold, reinforce, or fasten it. A strap may also be referred to as strapping. Strapping is most commonly used in the packaging industry.
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 strength, bending, shear, hardness, and torsion testing, providing valuable data for designing and ensuring the quality of materials. An earlier name for a tensile testing machine is a tensometer. The "universal" part of the name reflects that it can perform many standard tests application on materials, components, and structures.
In materials science, a triaxial shear test is a common method to measure the mechanical properties of many deformable solids, especially soil and rock, and other granular materials or powders. There are several variations on the test. In a triaxial shear test, stress is applied to a sample of the material being tested in a way which results in stresses along one axis being different from the stresses in perpendicular directions. This is typically achieved by placing the sample between two parallel platens which apply stress in one direction, and applying fluid pressure to the specimen to apply stress in the perpendicular directions.
Package cushioning is used to protect items during shipment. Vibration and impact shock during shipment and loading/unloading are controlled by cushioning to reduce the chance of product damage.
A bulk box, also known as a bulk bin, skid box, pallet box, bin box, gaylord, or octabin, is a pallet-size box used for storage and shipping of bulk or packaged goods. Bulk boxes can be designed to hold many different types of items such as plastic pellets, watermelons, electronic components, and even liquids; some bulk boxes are stackable.
The term unit load refers to the size of an assemblage into which a number of individual items are combined for ease of storage and handling, for example a pallet load represents a unit load which can be moved easily with a pallet jack or forklift truck, or a container load represents a unit for shipping purposes. A unit load can be packed tightly into a warehouse rack, intermodal container, truck or boxcars, yet can be easily broken apart at a distribution point, usually a distribution center, wholesaler, or retail store for sale to consumers or for use.
A wooden box is a container made of wood for storage or as a shipping container.
Filament tape or strapping tape is a pressure-sensitive tape consisting of a pressure-sensitive adhesive coated onto a backing material which is usually a polypropylene or polyester film and fiberglass filaments embedded to add high tensile strength.
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 boxes. In the context of international shipping trade, "container" or "shipping container" is virtually synonymous with "intermodal freight container", a container designed to be moved from one mode of transport to another without unloading and reloading.
Corrugated box design is the process of matching design factors for corrugated fiberboard or corrugated plastic boxes with the functional physical, processing and end-use requirements. Packaging engineers work to meet the performance requirements of a box while controlling total costs throughout the system. Corrugated boxes are shipping containers used for transport packaging and have important functional and economic considerations.
The edge crush test is a laboratory test method that is used to measure the cross-direction crushing of a sample of corrugated board. It gives information on the ability of a particular board construction to resist crushing. It provides some relationship with the peak top-to-bottom compression strength of empty singlewall regular slotted containers in laboratory conditions.
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 the associated processes.
Cardboard is a generic term for heavy paper-based products. The construction can range from a thick paper known as paperboard to corrugated fiberboard which is made of multiple plies of material. Natural cardboards can range from grey to light brown in color, depending on the specific product; dyes, pigments, printing, and coatings are available.
In technical usage in the shipping industry, a pail is a type of cylindrical shipping container with a capacity of about 3 to 50 litres. It can have straight or slanted sides and usually has a handle or bail. In non-technical usage, a pail is synonymous with a bucket.
Package handles, or carriers, are used to help people use packaging. They are designed to simplify and to improve the ergonomics of lifting and carrying packages. Handles on consumer packages add convenience and help facilitate use and pouring. The effect of handles on package material costs and the packaging line efficiencies are also critical. A handle can be defined as “an accessory attached to a container or part for the purpose of holding or carrying.” Sometimes a handle can be used to hang a package for dispensing or use.
A shipping tube, mailing tube, or cardboard tube is a shipping container used to ship long items. It is usually a long package with a narrow cross-section: square, triangle, or round.