The 10 decisive factors – and the role foam plays in them
For many companies, a drop test is the crucial proof that a product can withstand transport undamaged. The disappointment is all the greater when a newly developed package fails the very first test.
In this article, we focus specifically on the foam insert. As the central damping element, it absorbs a significant portion of the impact energy and substantially influences the stresses ultimately transferred to the product. Even minor design flaws can therefore cause packaging to fail the drop test – even if other components of the packaging system are correctly designed.
In practice, however, it turns out that the foam insert is rarely solely responsible. The cause usually lies in a combination of the insert's design, material selection, and a lack of compatibility with the product, geometry, and load profile.
In this article, we show the ten most common reasons why packaging fails drop tests – and what you should pay attention to during development.
1. The foam is too hard
Many people assume that the hardest possible foam offers the best protection. In fact, the opposite can be true.
If the material is too stiff, the impact energy is hardly absorbed and instead transferred directly to the product. The measured accelerations (G-values) increase significantly. Particularly sensitive devices such as measuring instruments, optics, or electronics can be damaged by even a single fall.
An optimally designed foam works like a spring: it yields in a controlled manner and converts some of the impact energy into deformation.
2. The padding thickness is insufficient.
Besides the material hardness, the available padding thickness plays a crucial role.
The greater the spring travel, the longer the shock can be absorbed. This reduces the maximum stress on the product.
Many projects aim to save material or develop the most compact packaging possible. However, if the padding is made too thin, the foam reaches its load-bearing limit and can no longer adequately absorb the impact.
3. The contact surface is too small.
A common design flaw lies in the contact area between the product and the foam.
If the weight rests on just a few small contact points, the surface pressure increases significantly. The foam becomes locally overloaded and loses some of its damping effect.
Often, the protective effect can be significantly improved simply by using a larger or better distributed contact area – without using additional material.
4. The product weight was not taken into account.
Each type of foam has an optimal load-bearing capacity.
A material that provides excellent protection for a two-kilogram measuring device may be completely unsuitable for a ten-kilogram industrial component.
Therefore, material selection should always be based on weight, center of gravity, drop height and product sensitivity.
5. The focus was ignored.
Many technical products do not have a uniform center of gravity.
Particularly asymmetrical products or assemblies with heavy individual components generate additional torques upon impact, which are often underestimated.
If the product falls on a corner or edge, additional rotational movements occur. This puts some areas under significantly more stress than others.
Good packaging therefore takes into account not only the total weight, but also the weight distribution within the product.
6. The actual transport loads were underestimated.
Not every shipment is handled with care.
Packages are moved on conveyor systems, stacked, loaded, and sometimes dropped from heights of over one meter. International testing procedures such as ISTA simulate precisely these stresses.
Those who design their packaging solely for "careful transport" often experience surprises during actual shipping.
7. The product may move within the packaging.
Even high-quality foam only provides reliable protection if the product is securely fixed.
Even a few millimeters of play can cause the component to accelerate within the packaging and hit hard boundaries.
A precisely manufactured foam insert prevents these relative movements and distributes the forces in a controlled manner.
8. The material properties were chosen incorrectly.
PE-, PU-, EPP- or EPDMFoam materials differ significantly in their damping properties and long-term durability. Upon impact, the product's kinetic energy must be dissipated within milliseconds. The better the foam can absorb this energy over a longer distance, the lower the stress on the product.
A frequently underestimated aspect is the creep behavior of the material. Some polyurethane (PU) flexible foams can develop compression set under continuous stress over time. This means they do not fully regain their original shape and resilience. As a result, the damping effect can deteriorate over time – especially in reusable packaging or when products are stored in the packaging for extended periods.
Materials such as PE or EPP foam offer greater dimensional stability in many applications and retain their protective properties better over many transport cycles.
Therefore, there is no single "best" foam. The crucial factor is selecting the material to suit the application, transport conditions, and desired lifespan.
How a foam insert absorbs shocks
Impact /Fall
Upon impact after the fall, energy is transferred to the packaged product.
Deformation
The foam compresses and increases the suspension travel.
Energy intake
The impact energy is dissipated through the spring travel in the material.
Residual acceleration
Only the remaining energy reaches the product in the form of a reduced G-force.
9. The packaging was never tested under real-world conditions.
Simulations and empirical data are helpful, but they do not replace practical testing.
An instrumented drop test with acceleration sensors shows what loads actually act on the product.
This often leads to insights that were not visible in a purely theoretical interpretation.
10. The entire packaging was not considered as a system.
Protective packaging consists of more than just a cardboard box or a foam insert.
The interplay of all components is crucial: outer packaging, inner padding, fixing, center of gravity, material properties, manufacturing tolerances and transport route.
Only when all elements are coordinated does a package emerge that provides reliable protection.
How does NOVAPOR manufacture reliable protective packaging?
At NOVAPOR, the development of protective packaging doesn't begin with the selection of a material, but with a detailed analysis of the product to be protected. This includes considering factors such as weight, center of gravity, and sensitivity to impacts. The subsequent transport route, potential drop heights, and storage and handling requirements are also factored into the development process.
Based on this information, we select the appropriate materials and develop a design that effectively dissipates forces and reliably protects the product throughout the entire transport process. In addition to the protective effect, we also consider factors such as the available installation space, the desired packaging size, and cost-effective mass production.
Through prototypes, practical trials, and – if necessary – instrumented drop tests, we test our developments even before series production. This allows potential weaknesses to be identified and optimized early on.
The result is not a standard package, but a custom-designed protective package that is optimally tailored to the product, transport conditions and economic requirements.
Most drop tests fail not because of inferior materials, but because of an insufficient match between product and packaging.
Even small changes to padding thickness, contact area or material selection can significantly reduce impact stress and save material at the same time.
Those who systematically develop protective packaging and test it under real-world conditions not only increase transport safety, but also sustainably reduce complaints, transport damage and consequential costs.
Our approach to drop-testable packaging
NOVAPOR develops protective packaging that proves its worth in practice – not just in the test lab:
analysis
Product, weight, requirements
focus
Investigation and evaluation
analysis
Product, weight, requirements
focus
Investigation and evaluation
Choice of material
Cushioning characteristic curve and key values
construction
CAD design of the foam insert
Choice of material
Cushioning characteristic curve and key values
construction
CAD design of the foam insert
prototype
Prototype construction and functional testing
Drop test
Testing according to ISTA / real loads
prototype
Prototype construction and functional testing
Drop test
Testing according to ISTA / real loads
optimization
Adjustments until the optimal solution is found.
Series production
Quality assurance and production
optimization
Adjustments until the optimal solution is found.
Series production
Quality assurance and production
analysis
Product, weight, requirements
focus
Investigation and evaluation
Choice of material
Cushioning characteristic curve and key values
construction
CAD design of the foam insert
prototype
Prototype construction and functional testing
Drop test
Testing according to ISTA / real loads
optimization
Adjustments until the optimal solution is found.
Series production
Quality assurance and production
Frequently asked questions (FAQ)
Why did my packaging fail the drop test?
The most common causes are unsuitable material selection, insufficient padding thickness, an incorrect contact surface, or inadequate product securing. A disregarded center of gravity or unrealistic assumptions about the transport route can also lead to packaging failing the drop test.
Which foam is best suited for drop tests?
There's no single answer to that. The choice depends on factors such as product weight, sensitivity, drop height, and environmental conditions. Depending on the application, PE, PU, EPP, or EPDM foams may be suitable.
Can a thicker foam insert improve a drop test?
Yes, often. Greater pad thickness increases the braking distance and thus reduces the maximum impact load. However, the thickness must always be appropriate for the material hardness and the product weight.
Why is the contact area so important?
A larger contact area distributes the forces more evenly across the foam. This prevents local overloading and improves the damping effect.
Is a sturdy cardboard box sufficient protection?
No. The cardboard box primarily protects against external influences and provides stability. The actual impact protection is provided by the inner packaging or the foam insert.
What drop height must a transport package withstand?
This depends on the shipping method and the customer's requirements. International standards such as ISTA define different drop heights depending on the package weight, simulating realistic transport conditions.
What does the G-value mean in a drop test?
The G-value describes the maximum acceleration that acts on a product during an impact. The more fragile the product, the lower this value should be. Many electronic or optical devices require maximum loads of approximately 20 to 50 G, while robust industrial components can withstand significantly higher values.
When should a drop test be performed?
Ideally, this should happen during the development phase. This allows weaknesses to be identified before the packaging goes into mass production. This saves costs and reduces the risk of subsequent transport damage.
How does Novapor develop transport-safe packaging?
If you are unsure whether your packaging can reliably withstand the actual stresses of transport, we would be happy to assist you with the technical design and optimization of your protective packaging. We develop customized packaging based on product weight, center of gravity, fragility, and transport route. Through design, material selection, prototyping, and drop tests, we create protective packaging tailored to the specific application.
Is it possible to calculate the cost of packaging before construction?
Partly, yes. An initial design can be created using cushioning curves, material data, and empirical data. However, prototypes and real-world drop tests are always recommended for safety-critical products, as the behavior of complex systems cannot be fully calculated.