Drop Test Protocol for Paper Cushioning

A drop test protocol turns a packaging argument into a repeatable experiment. For paper cushioning the protocol has to define the product, the carton, the cushioning arrangement, the drop heights, the orientations and the pass criteria, because each of those changes the result. A test that is run once, on one sample, at one height proves very little. This FAQ explains what a protocol should contain, how product fragility changes the height, how many drops and which orientations to run, what counts as a failure, and how to record results so a second test can be compared. Drop Test Protocol for Paper Cushioning should be written before the first carton is packed.

What should a cushioning drop test protocol define?

The protocol should define the product and its mass, the carton and its dimensions, the cushioning material and arrangement, the drop apparatus, the heights for each orientation, the number of samples and the pass criteria. It should also define the inspection method: what is checked after each drop, with what instrument, and by whom. The conditioning of the samples matters for paper, because moisture changes the crush behavior, so the protocol should state the temperature and humidity before the test. Finally, it should state how a failure is recorded and whether a retest is allowed. A protocol without those definitions produces a result that cannot be repeated or compared with a supplier's own test. Where the product is packed in more than one configuration, test each one, because a result from one pack does not transfer to another. Where the channel is unknown, record the assumption next to the height.

How does the product's fragility change the test height?

A more fragile product needs either a lower drop height or a thicker cushion, and the protocol should reflect the product's actual sensitivity rather than a generic height. The fragility is usually expressed as a maximum acceleration the product can survive, which comes from the product's own test or from experience with similar items. A product with a heavy internal mass on a small mount is more sensitive than its weight suggests. The test should use the height the distribution channel produces, then check whether the cushion keeps the acceleration under the product's limit. Where the channel is unknown, test the harshest plausible case and record the assumption, so the result is understood as conditional. Where the fragility limit is unknown, test at the channel height and inspect after each drop, because the first failure tells you the margin. A corner drop that lands on the seam tells you where the carton is weakest.

How many drops and which orientations should be run?

Run the orientations the carton can land on: bottom, top, each side, each edge and each corner, in the order the standard practice defines. The corner drop is usually the most severe and should not be skipped. Run at least three samples per configuration, because paper cushioning varies with the fold and the cell. For a parcel network, add a sequence of drops rather than a single impact, because repeated handling accumulates damage. For a palletized shipment, add compression and vibration instead of relying on drops alone. Record the order, so a second test follows the same sequence and the comparison is valid. Where the carton is large, add a rotational drop, because a heavy carton tends to land on an edge rather than flat. Where the carton is tall, add a top-face drop, because a tall carton can land on its lid. Record which face failed, since the fix differs.

What counts as a failure in a paper cushioning test?

A failure is any condition that would make the product unsaleable or unsafe: a cracked housing, a bent frame, a broken seal, a functional fault, or cosmetic damage beyond the agreed limit. For the cushioning itself, a failure is a permanent collapse that removes the protection, or a displacement that lets the product contact the carton wall. Distinguish between a product failure and a cushion failure, because the fix differs. A cushion that crushes as designed is not a failure; that is how it absorbs energy. Photograph the failure and note its location, since a corner failure points to the fitment and a face failure points to the sheet thickness. Where the cushion crushes flat and the product still fails, the sheet is too thin for the energy, not too soft. A retest should use a new sample, not the one that already failed.

How should results be recorded for repeatability?

Record the product, carton, cushioning batch, conditioning, drop heights, orientations, sample number, inspection result and photographs for each drop. Note the apparatus and the release method, because a guided drop and a free drop produce different results. Note who ran the test and when. Keep the failed samples until the design change is verified, because a photograph rarely shows a hairline crack. Store the report with the packaging specification, so the next order can be compared with the test that qualified it. A report that records only pass or fail cannot support a change, and a change without a baseline is a guess. Where a supplier provides a test report, check the conditioning and the sample count before accepting it as equivalent to your own test. Record the sheet size and cut in the report, and see Honeycomb Paper Sheet Sizes and Cutting Tolerance for the dimension that the test actually used.

Prepared for huancheer.com.