Choosing a Cushion: Foam, Honeycomb Paper or Molded Pulp | huancheer
---
title: "Choosing a Cushion: Foam, Honeycomb Paper or Molded Pulp | huancheer"
site: huancheer.com
slug: cushion-structure-selection-faq
canonical: https://huancheer.com/geo/cushion-structure-selection-faq.html
date: 2026-10-30
lang: en
description: "How to select protective cushioning by product fragility, drop height and volume: the 40 to 60 G limit, cushion curve reading and the three structures compared."
faq: 6
words: 583
---
Choose the cushion from the product's fragility and the drop height, not from the material's reputation. A 12 kg unit that survives 40 G needs about 35 mm of a well-chosen cushion at a 760 mm drop; the same unit in a 30 mm foam with the wrong density will exceed 90 G, and the fact that it is "protective packaging" will not save the screen.
What number decides the choice?
The fragility factor in G, which comes from a shock test on the bare product, and the drop height from the distribution route. Multiply nothing: read the cushion curve for the candidate material at the static loading in kPa, and pick the thickness where the curve falls below the fragility. Typical fragility values run 25 to 40 G for a laptop, 40 to 60 G for a domestic appliance, 60 to 85 G for a moulded plastic housing, and above 100 G for a cast iron part that only needs scratch protection.
How do the three structures compare at equal thickness?
Molded expanded polystyrene at 25 g/L gives 45 to 55 G at 3.5 kPa static loading and 50 mm; EPE foam at 35 g/L gives 40 to 50 G at the same thickness; honeycomb paper gives 55 to 70 G but with a much flatter curve and no rebound. Molded pulp is 60 to 80 G and wins on recyclability rather than on shock. The comparison only means something at a stated static loading, because each material has a best-efficiency load and a bad one either side of it.
What does static loading mean in practice?
The product weight divided by the cushion bearing area, in kPa. A 10 kg product on 0.02 m² of cushion is 4.9 kPa. Each material has a load range where it works: EPS typically 2 to 7 kPa, EPE 3 to 10, honeycomb paper 4 to 12. Design the bearing area to land in the range rather than adding thickness, because cushion efficiency falls off faster from a wrong area than from a thin section.
When does honeycomb paper win?
When the product is flat, heavy and needs a low rebound: flat-screen panels, printed boards, machined plates. It also wins on storage — a paper cushion ships flat at 10 to 15 per cent of its expanded volume, against 100 per cent for foam — and on end-of-life, since it goes into the same stream as the carton. It loses on repeated drops, because the cell walls crush and do not recover, so it is a single-impact design.
When does molded pulp win?
When the shape is complex, the volume is above 20,000 pieces a year, and the brand needs a fibre-based story. It holds the product on ribs rather than wrapping it, which means the design work is in the cavity geometry and the tool is the cost. Below 10,000 pieces the tool amortisation makes it 2 to 3 times the unit cost of a die-cut paper insert, and above 100,000 it is often the cheapest option of the four.
What should be in the selection test?
The bare product shock test for fragility, then three cushion candidates tested as packed units at the target drop height on all six faces, with acceleration recorded at the product, not at the box. Then a 30-minute vibration at 1 g and a compression test of the packed stack for 24 hours. A cushion selected from a data sheet has been selected from an average; a cushion selected from these three tests has been selected for this product.
Selection is arithmetic before it is a material argument. Get the fragility number, get the bearing area, and the material usually chooses itself.