Compression forces are some of the main risks faced by goods and packages during the distribution cycle. In our guide on how to use a compression tester, we analyze what a compression tester is, what kinds of loads can be tested, and offer a step-by-step guide to use the equipment.
What is a compression tester?
A compression tester is a machine that can test a material’s resistance to compression (generally used in packaging) and to the creep test.
A compression testing machine can be used to verify the resistance of shipping containers, pallets and load units to compression forces or, in other words, to forces that push from opposite sides of a package.
A compression tester is therefore essential in the design of an adequate and optimized package that is capable of performing when faced with transportation hazards and minimize damages and extra costs.
A number of international standards call for box compression tests, as well as compression tests on other materials, including:
- EN 15552:2008 Packaging: Complete, fillet transport packages and unit loads. Performance testing schedules for common distribution chains.
- ASTM D4169-16 Standard practice for performance testing of shipping containers and systems.
- ISTA Procedures 1C, D; 2A, B; F, H; 4 Series; 6-FEDEX; 6-SAMSCLUB, 6-AMAZON.COM.
When should you use a compression tester?
Certain industries are strongly dependent on the ability to calibrate a material in a way that it can withstand compression forces.
During warehouse storage, it is common for cardboard boxes to be stacked one on top of the other, putting them to the test as a result of the compression forces exerted on them. In order to guarantee that they will not collapse, a machine is necessary that can, as part of a packaging laboratory measure the protective ability of a specific package against this and other situations. The box compression test and the carton compression test are used to find out up to which point this material can protect the goods without failing.
The BCT (Box Compression Test) consists of applying a gradually larger compression force to a load until it fails. In this way, you can obtain a force-deformation curve that allows the resistance of a package to be determined and provides enough information to make decisions in relation to the packaging (e.g., whether to choose a more resistant package).
The box compression strength tester is therefore a very important item when it comes to designing a package that is suitable and resistant. It is also extremely useful to make sure that the boxes will maintain their integrity during storage and handling.
How to use a compression tester
In order to perform a compression test on boxes or other materials, the first step is finding the right compression tester that is suitable for the loads to be tested.
In the case of Safe Load TT, our compression tester allows for testing of shipping containers, pallets and load units.
We have designed a full range of compression testers, available in 25kN to 200kN variants, that can be used for the required range of tests. Furthermore, they are all capable of performing tests at different temperatures and humidity levels since they can be installed inside environmental chambers, mimicking the real environmental conditions that might be experienced by the loads during transportation and storage.
Regarding how to use a compression tester, there are several steps involved:
- Preparing the testing unit. This should include a representative sample of the products, whether they are boxes, pallets or containers.
- Then, the load is placed in the compression tester between the compression platen and the base.
- When performing the test, the machine will move the compression platen so that it exerts pressure on the unit being tested and applies the pressure forces specified by the technician.
The compression tester is driven by an electric motor that moves the compression platen up and down by turning a screw.
The machine measures the displacement of the pressure platen by means of a linear encoder with micrometric precision, and the force by means of a load cell. These two technologies can meet the precision requirements of international standards.
The compression tester also counts with safety features such as limit switches (which stop the moving part of the machine at the end of its track) and emergency stop switches (which would stop the machine in case of danger).
Depending on the chosen machine, the test will be able to apply different forces and perform different types of tests. In the case of the compression testing machine by Safe Load Testing Technologies, our equipment performs three types of tests:
- Constant rate compression: applies an increasingly larger compression force until the tested unit fails.
- Press & hold: applies forces to the load and holds the pressure, so as to test the resistance to these situations. Through this test, the compression tester offers a simulation of the type of threat that the stacking of load units for a specific amount of time implies to the package.
- Press & release: applies a compression force to a load and then releases it, testing whether the package has been able to withstand it.
In this way, it is possible to study in real-time the protective ability of the package in the face of different types of compression forces, tailored to the real conditions experienced during storage and transportation.
In the case of Safe Load TT’s equipment, a series of intuitive controls on a touchscreen allow for the test and all variables to be easily controlled.
A specific example of how to use a compression tester
A company decides to test what type of package is suitable to transport its product, which is quite delicate. The load weighs 10kg and is placed in a package that, according to previous tests, can withstand forces of up to 60kg without failing. This means that it can withstand stacking up to 7 levels during storage and transportation.
After analyzing the distribution cycle, it is determined that, in reality, shipments are performed on pallets that can stack boxes up to 3 levels. This allows for the decision to optimize the package in two ways: choose a less resistant and cheaper packaging or start shipping in stacks of 4 to 5 levels.
In any case, thanks to the compression tester, the company manages to save costs while still guaranteeing the safety of the loads during shipping, handling and storage.
What can a compression testing machine determine?
Testing results are expressed according to different variables, depending on the way in which it has been performed. Testing is generally performed until a rupture in the materials is detected, or up to a certain limit (for example, a maximum number of stacked boxes).
This information is highly valuable to characterize the package across different phases. In the design phase, it allows for the selection of the best materials that are capable of protecting the goods. Later on, the compression tester can also ascertain whether the chosen packaging is adequate.
In any case, these efforts will result in an optimized package that is tailored to the risks that it will face during the distribution cycle and is capable of protecting the goods, avoiding unnecessary costs.
At Safe Load TT we have been advising companies for two decades in relation to their transportation simulations. We deliver turnkey equipment, designed for intuitive use, with a simple maintenance and compliant with a variety of international standards. In addition, we offer advice on the tests to be performed, training on the use of the equipment and post-sales services.
Get in touch with us and we will set the process of optimizing your packaging in motion.