Mechanical tests


Why use mechanical tests? Because they provide you with a quick figure of how much force the end user needs to open a packaging.


End users’ opening grips

Before it is possible to make a mechanical test it is important to know the end users’ opening grips, which can be identified by using end user studies and video observations (see method for observation).


It is important that the mechanical test is as close to the opening procedure people use, otherwise the result will not be accurate. The end users’ opening grips are not always similar. It is a good idea to measure the force needed for the most frequently used opening grips in order to create an accurate picture of the force potentially needed for opening the packaging.


Carrying out the mechanical test

The mechanical test can be made on e.g. a pull bench (for most types of packaging) or in a torquemeter (for packaging types with screw caps). Both will measure the force needed to open. Generally 10 repetitions for each type of packaging will be sufficient. You will then be able to calculate average and standard deviation (SD) from the results. The average for the mechanical test (only averages with a small SD) can be used to evaluate how easy the packaging is opened. Use the average from the mechanical test and insert it together with the packaging dimensions in the calculation model for critical force in order to get a picture of how many men and women potentially will be able to open the packaging.

It is important to consider the SD as this expresses how similar the packaging is to open from time to time. The average will also be influenced by single measurements differing a lot from the rest of the measurements. It is therefore important that the SD is small compared to the average.



Mechanical test carried out at Danish Tecnological Institute, Taastrup