The distribution of products requires that none of the product’s properties are negatively affected since the moment the product is finished until it arrives at the customer’s doorstep. This is one of the main purposes of packaging. To accomplish this, a package must withstand the entire distribution cycle. Among other things, this implies that it must withstand the hazards of transportation, which include accelerations that might affect the load’s upright position. When the load is deformed as a result of speed and fails to maintain its shape, this might lead the cargo to topple over.
The main problems related to poor stability
The problem with deformation is not just about the cargo toppling over. If the load gets deformed, it might get rejected by the recipient at any of the logistics centres. In automated warehouses, there is usually a clearance gauge where the load is received that discards loads that are deformed since they are at risk of toppling over. Outside of automated warehouses, an excessive cargo deformation might prevent it from being stored on shelves, and even lead to serious accidents.
The greatest problem with a package that fails to stay upright is the lack of stability. If the packaging system is not stable enough, the load might topple or even lead to serious consequences, which include a loss of product to personnel or nearby persons being crushed. An accident that is, unfortunately, common, takes place when the doors of a container or transport are opened and the load is tilted against the door. When the door is opened, it results in an avalanche that sometimes leads to crushing fatalities.
Another problem that results from a lack of stability during transportation is the cargo projecting out of the vehicle. This problem is so serious that governments around the world require the packaging and transport to withstand a certain degree acceleration. Typically, 0.8G in the direction of travel and 0.5G sideways and backward. Countries as distant as the United States, Australia and Japan have transport stability requirements in place. The European Union has gone one step further and also established the EUMOS 40509 standard to evaluate the stability.
Standards and regulations to consider
Nowadays, there are several policy-setting bodies that are working toward regulating stability and testing procedures. Two of these testing procedures are the tilt test and the horizontal stability test.
Through testing, companies can also enjoy other benefits of transport simulation in relation to package and distribution optimization:
- Cost savings, avoiding over-packaging and shrinkage due to under-packaging.
- Increased safety, reducing damages to the goods during shipping & handling while guaranteeing the safety of the transport operator.
- Increased customer satisfaction, who receives a product in good condition.
Tilt testing consists of a testing procedure to evaluate the stability of a load under conditions that are similar to those that take place during transportation, in a laboratory setting. For the performance of this test, the load is tilted until it reaches a predetermined tilt or until failure, observing how the package reacts in order to improve it.
The load becomes a complex unit for which it is necessary to know how the packaging, pallet and handling equipment interact. The package tilt simulation evaluates the resistance of cargo securing systems.
Performing tilt simulation testing enables companies to enjoy a series of benefits:
- On one hand, it is a simple method to ensure that the cargo maintains its rigidity during transportation. This means that this method is highly recommended as a test to be performed at the end of the production line.
- In addition, this method is highly recommended throughout various phases of the analysis of a package, such as quality control systems or when comparing different packages during design.
- Tilt simulation is also particularly important at a time when sustainable package initiatives are being lauded and incentivized both by government bodies and the end customer. Performing tilt testing therefore enables companies to reduce packaging materials and their weight, optimizing the packaging of unit loads and increasing their sustainability.
When focusing on the types of products that might benefit the most from this test, this could be the case for products with a high rigidity that are transported as a compact unit in packages with little slack. This would include companies of the furniture or ceramics sector.
Tilt simulation process
The performance of a tilt simulation can be broken down into three basic steps:
- The sample, prepared for the simulation, is placed on a platform, securing it using the cargo securing system to be tested.
- The load is inclined up to a predetermined angle. This angle is defined based on the coefficient of sliding friction, the required resistance and the mass being tested.
- Once this angle is reached, the system undergoing the test must not exceed the deformation threshold for a given amount of time.
When extrapolating it to palletized loads, two methods can be used:
- Verification: this consists of tilting the load up to the angle required to determine the coefficient of sliding friction while under the acceleration that it needs to withstand. Once the tilt equivalent to the target Gs is reached, the position must be maintained for at least 5s.
- Characterization: this implies tilting the unit load until failure. After knowing the angle of failure and the coefficient of sliding friction of the surface, it is possible to calculate the equivalent acceleration in order to define a stability limit.
When evaluating lashing systems, it is necessary to use machines especially designed to tilt package testing. However, when evaluating packages, any system that allows one part of the sample to be elevated may be used.
Limits of tilt simulation
The EN12195 standard includes tilt testing as one of the methods to guarantee a safe cargo stowage.
This test is effective to ensure the stability of a load under transport-like conditions; however, this standard has a few limitations:
- Toppling over or shock might occur when the center of gravity of the load exceeds the turning point. It is therefore not possible to test accelerations that exceed that point.
- In specific cases (such as bulk cargo), the load might shift when modifying the inclination, thereby altering the test result.
- This is a static test, which means that it cannot reproduce certain dynamic effects experienced by loads during transportation.
- Other limitations include the testing of loads with a low resonance frequency or the reproduction of stabilities in excess of 1G.
Differences between the tilt test and the horizontal stability test
It is quite easy to see the difference in response to a static phenomenon, as opposed to a dynamic one, just by comparing what happens in our cars when we brake, increasing the pressure on the brake pedal all the way, tapping the pedal or slamming on the brakes.
Different studies have demonstrated that the dynamic response resulting from a sudden change in acceleration augments the effect due to phenomena related to cargo resonance.
The cargo stability test consists of subjecting the sample to a rectangular acceleration pulse and studying the deformation that takes place during the performance of the test and at the end.
There are different standards that outline how to perform a horizontal stability test, with one of the most widespread being the one defined in the EUMOS 40509 standard.
The horizontal stability test allows for the reproduction of the effects of the dynamic phenomena that take place when accelerating during transportation.
The foregoing allows us to conclude that the tilt test is not the same as the horizontal stability test, even if they have similar applications in certain cases. There are a number of differences: the tilt test does not allow for the reproduction of the dynamic response, but it can reproduce some of the effects. The means to perform the tilt test are more affordable. The tilt test is limited by the dynamics of the sample, and there are certain levels that will be impossible to test because the load topples over before the effects of the equivalent acceleration are experienced.
In reality, one should not think these tests -tilt test or acceleration test- to be mutually exclusive; even when the tests might have their nuances, these two methods can complement each other. The horizontal testing method is the most adequate to verify the stability, but if one does not count with a horizontal stability tester such as the Boomerang Horizontal Stability tester, for example, the tilt method may be used during the entire package design phase and, once the prototypes are ready, verify their stability using a stability tester. If there is no horizontal stability solution at hand to perform it, the equivalent stability value for the prototype as measured on the tilt tester can be used as a way to verify the quality at the end of the line.
How we can Safe Load TT help you?
At Safe Load Testing Technologies we are leaders in the design of projects to improve the stability and safety of loads throughout the distribution cycle.
Our track-record in the transport simulation and packaging optimization industry allows us to design testing solutions, such as the acceleration or tilt tests, in a way that is precise and reliable. Moreover, our solutions are designed to comply with the regulations in effect and obtain economic and sustainability benefits.
Do you want to improve the stability and safety of your loads? Are you looking for a personalized solution tailored to your distribution cycle? Get in touch with us and let’s talk about how we can help.