Stretch Wrap and Pallet Stability: Using Method B to Benchmark Suppliers

Stretch Wrap and Pallet Stability: Using Method B to Benchmark Suppliers

Stretch wrap plays a central role in pallet stability. It must prevent loads from shifting or collapsing during transport, while also resisting puncture from sharp edges and corners. Traditional metrics such as elongation and holding force are important, but they do not fully describe how the film behaves under sudden, localized impact. Method B dart impact testing adds a more realistic perspective when benchmarking stretch wrap suppliers.

Method B uses a larger dart and a higher drop height (1.50 m) than Method A, resulting in significantly higher impact energies. For stretch wraps and industrial pallet films within the standard thickness range, this method can simulate worst-case events such as impacts from pallet corners, strapping buckles, or unexpected collisions. By measuring the failure mass M50 under Method B, you gain a quantitative measure of how resistant a film is to catastrophic puncture.

To benchmark suppliers, start by defining a consistent test protocol. All candidate films should be tested at the same thickness range, conditioning conditions, and Method B settings. Using the staircase method, determine M50 for each film. It is good practice to test multiple rolls and multiple positions within each roll to capture manufacturing variability. The result is a data set that reflects both average toughness and consistency.

When analyzing the data, consider more than just the average M50. The spread of results and the presence of outliers can be telling. A supplier whose film occasionally shows very low M50 values may pose a higher risk of unexpected pallet failures, even if the average is acceptable. On the other hand, a supplier with slightly lower average M50 but very tight distribution might offer more predictable performance.

Beyond pure performance, Method B results can be combined with cost and sustainability considerations. For example, if a higher-priced film offers only marginal toughness improvements, it may not be worth the premium. Conversely, a downgauged film that maintains M50 within an acceptable range may deliver material savings without compromising safety. Using Method B dart impact testing in this structured way helps logistics centers and brand owners make evidence-based decisions about stretch wrap suppliers and specifications.