Honeycomb Paper GSM Selection FAQ: 90, 110 and 130 gsm

Choosing a core grade by habit is expensive in both directions. This FAQ answers the questions packers ask when they match a honeycomb grade to a product and a route.

Which honeycomb GSM should I choose?

Choose by the compression load the packed carton will see, not by the heaviest grade available. A 90 gsm core suits light products and short routes, 110 gsm covers most general export cartons, and 130 gsm is for heavy items, high stacks or long sea legs. Cell size matters as much as weight: a small cell at 110 gsm can outperform a large cell at 130 gsm for a light product because the load is distributed over more walls. Test two or three grades at the same cell size on your own packed carton, and choose the lightest one that passes with a margin. A useful check is to weigh a carton packed with each grade and compare it with the same carton packed to the tested specification. The difference in packed weight is the material cost of over-specification, and on a container it also changes the freight because weight and volume both matter. A grade that passes with a comfortable margin is not automatically the better choice; the margin has a cost, and the buyer should decide how much margin the route actually needs.

Why did a heavier grade not fix corner breakage?

Because the failure may come from the cell geometry rather than the paper weight. A large cell leaves fewer walls to carry the load, and the cushion densifies early, transmitting shock to the product. Adding weight to the paper delays that but does not change the geometry. Moving to a smaller cell at the same or a lighter grade often solves the problem at lower cost. Run a compression test on the packed carton and look at where the curve enters densification, then compare that load with what the stack applies. Ask how the supplier controls cell size and expansion at the line. A roll that is slit slightly wide can open to a different thickness, and a glue pattern that is off can leave cells that do not hold their shape. Request the tolerance for expanded thickness and the inspection frequency, then measure a sample at goods-in. A cushion that is ten percent thinner than specified loses a meaningful share of its compression performance, and the loss is invisible until the damage appears.

How does humidity change performance?

Paper loses compression strength as moisture content rises, and a container on a long route can hold high humidity for weeks. A pack that passes in a dry lab may fail at sea. Condition the test samples at the humidity the route will produce, or apply a derating factor agreed with the supplier, and protect the carton with a moisture barrier if the product is sensitive. Store rolls flat and dry, wrap the pallet for the ocean leg, and record the storage humidity so a later failure can be explained rather than guessed at. Keep the packaging specification with the carton drawing rather than in a separate document. When a carton changes, the cushioning spec should be reviewed in the same meeting, because a change in the box dimension changes the void and the way the cushion sits. A spec that lives in a different folder is the one that gets missed, and the result is a pack that passed the test on a previous carton and fails on the new one.

How do I compare cost between grades fairly?

Compare cost per protected unit, not cost per roll. Calculate how much expanded cushion one roll yields at the specified cell size and thickness, then divide the roll price by the number of cartons that can be packed to the tested specification. A lighter grade that needs more layers to pass a drop test can cost more than a heavier grade used in a single layer. The same calculation exposes over-specification: a 130 gsm core on a light product passes easily but consumes more paper and more warehouse space per carton. Train the receiving team to check the roll label against the purchase order before the roll goes to the line. A mixed pallet with two grades is efficient for the supplier and dangerous for the packer, because the wrong roll produces a pack that looks correct and performs worse. A coloured label or a distinct core colour makes the grade visible at a glance, and that simple visual control prevents most of the mix-ups.

What line discipline keeps the specification working?

Open the cells evenly to the specified thickness and check with a gauge at the start of each shift, because stretching one edge creates a soft side that collapses first. Store rolls flat, dry and off the floor, rotate stock, and record the roll lot on the packing sheet so a claim can be traced to a batch. Keep one retained sample per lot and review damage data monthly against grade and cell size. Most improvement in a cushioning program comes from those habits rather than from changing supplier. Finally, review the damage data every quarter against the grade, the cell size and the route. A change in the carrier, the container or the product mix can move the failure rate without any change in the material. A quarterly review catches that drift before a customer does, and it gives the buyer evidence for the next negotiation rather than an impression that the packing got worse.

A related decision is the number of layers. Two layers of a lighter grade can outperform one layer of a heavier grade in a deep void, because the layers slide and distribute the load, but the packing time doubles. Test the layer count on the actual carton and compare the labour cost with the material saving. A pack that is cheap per square meter but slow to assemble can cost more per carton than a single heavier layer.

Finally, ask the supplier for the recycled content and the fiber source if the pack carries an environmental claim. A honeycomb core is often made from recycled kraft, but the claim needs a chain of custody and a definition that the customer's market accepts. Keep the documentation with the specification, and make sure the claim wording matches what the certificate covers rather than what the sales sheet suggests.

A final point on documentation: keep the compression curve, the conditioning humidity, the cell size and the roll lot together in one file for each grade used, and review it whenever the carton or the route changes. When a customer claim arrives, the first question is which material was in the carton, and a record answers it in seconds. A supplier who provides the curve with the shipment is easier to defend than one who provides a datasheet once a year, and the file costs nothing to maintain.