How egg cartons are made
A pulp egg carton is recycled newspaper that was sucked onto a wire mold and baked dry.
- stations
- 6
- things upstream
- 14
- raw sources
- 7
- steps from the ground
- 5
The short version
Recycled paper is broken down in water into a thin fiber slurry. A mesh mold shaped like a tray of egg cups is dunked in it, and a vacuum pulls the fibers tight against the mesh. The damp pulp shell is then dried in an oven or between heated dies, which also makes the lid smoother and firmer.
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Break paper into slurry
Old paper and newsprint are churned in water until they separate into a runny slush of loose fibers.
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Vacuum fibers onto a mesh
A fine wire mesh in the shape of the carton dips into the slurry, or has slurry sprayed at it. A vacuum behind the mesh pulls water through, leaving a mat of fibers where the water was.
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Transfer the wet shell
The damp pulp shell is lifted off the mesh and carried toward the drying stage while it is still soft.
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Dry it firm
Ovens carry the damp shells through hot air until the water is gone, and each carton shrinks and stiffens as it dries.
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Press the lid smooth
Some cartons are pressed between heated mating dies while they dry. This gives the lid a smoother, firmer surface that takes printing better than the rough egg cups.
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Stack and ship
The finished cartons nest inside each other for the trip to the egg packer.
Worth repeating
- A British Columbia newspaper editor, Joseph Coyle, invented the egg carton in 1911 to settle a dispute over a farmer's broken eggs.
- The hinged lid that lets cartons of six or twelve stack was added in the 1950s by H.G. Bennett, working for the company Hartmann.
- Each dimple in the carton isolates its egg from the neighbors and soaks up shock, which keeps shells from cracking.
Back to the ground
Follow every input upstream and egg carton starts as these 7 raw sources.
Keep walking
Sources
Cite this page: "How egg cartons are made." Assembly Line, 2026-11-03. https://assemblyline.org/make/egg-carton