{"id":14764,"date":"2026-09-24T04:59:28","date_gmt":"2026-09-24T04:59:28","guid":{"rendered":"https:\/\/bonitopak.com\/wet-pressing-vs-dry-pressing-molded-pulp\/"},"modified":"2026-09-28T05:29:09","modified_gmt":"2026-09-28T05:29:09","slug":"wet-pressing-vs-dry-pressing-molded-pulp","status":"publish","type":"post","link":"https:\/\/bonitopak.com\/fr\/wet-pressing-vs-dry-pressing-molded-pulp\/","title":{"rendered":"Wet Pressing vs. Dry Pressing Molded Pulp Trays: How to Choose the Right Process for Your Product"},"content":{"rendered":"

By Leo Chan | Writer, BonitoPak | 20+ years in molded pulp packaging<\/em><\/p>\n

The choice between wet pressing vs dry pressing decides four things at once: how your tray looks, how thick its walls are, what the tooling costs, and what each unit costs. Everything else in a molded pulp quote follows from it.<\/p>\n

The short answer is simple enough. If your customer sees the tray, look at wet pressing. If the tray is hidden inside a box or carries something rugged, dry pressing does the job for less. The rest of this guide covers the cases where the answer isn’t that obvious.<\/p>\n

The Difference in One Table<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n
Facteur<\/th>\nPressage \u00e0 sec<\/th>\nWet pressing (thermoformed)<\/th>\n<\/tr>\n<\/thead>\n
How it dries<\/strong><\/td>\nFormed, then dried in an oven or dryer<\/td>\nDried inside heated matched tools<\/td>\n<\/tr>\n
Surface<\/strong><\/td>\nOne smoother side, one rough, visible fiber<\/td>\nBoth faces smooth and dense<\/td>\n<\/tr>\n
Typical wall<\/strong><\/td>\nThicker<\/td>\nThinner<\/td>\n<\/tr>\n
Detail and draft angles<\/strong><\/td>\nSofter detail, more draft needed<\/td>\nFine detail, minimal draft<\/td>\n<\/tr>\n
Outillage<\/strong><\/td>\nSimpler and cheaper<\/td>\nHeated matched tools, more expensive<\/td>\n<\/tr>\n
Cycle time<\/strong><\/td>\nFaster output per line<\/td>\nSlower, limited by the heated press<\/td>\n<\/tr>\n
Unit cost<\/strong><\/td>\nPlus bas<\/td>\nPlus \u00e9lev\u00e9<\/td>\n<\/tr>\n
Id\u00e9al pour<\/strong><\/td>\nEgg trays, industrial dunnage, seedling trays, hidden inserts<\/td>\nRetail packaging, electronics, cosmetics, anything on display<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

What Each Process Actually Does<\/h2>\n

Both processes start the same way. Recycled paper or plant fiber is pulped with water, and a vacuum pulls that fiber onto a mesh mold shaped like the product.<\/p>\n

Pressage \u00e0 sec<\/strong> releases the formed part and dries it afterward, usually in an oven or a multi-layer dryer. Because the part dries unsupported, the walls stay thicker and slightly springy, and the surface keeps the texture of the mesh on one side.<\/p>\n

Pressage humide<\/strong>, often called thermoforming, dries the part between heated tools under pressure. The fiber is compacted while the water leaves, which produces a thin, dense wall with two smooth faces and crisp detail. No separate oven stage is needed.<\/p>\n

That single difference, drying inside the tool versus outside it, explains every other item in the table above.<\/p>\n

Where the Industry Types Fit In<\/h2>\n

The International Molded Fiber Association (IMFA) classifies molded fiber into four types, and it’s useful shorthand when you talk to suppliers.<\/p>\n

\n\n\n\n\n\n\n\n\n
Type<\/th>\nDescription<\/th>\nTypical wall thickness<\/th>\n<\/tr>\n<\/thead>\n
Type 1<\/strong><\/td>\nThick wall, single mold<\/td>\nAbout 5 to 10 mm<\/td>\n<\/tr>\n
Type 2<\/strong><\/td>\nTransfer molded, one forming and one transfer mold<\/td>\nAbout 3 to 5 mm<\/td>\n<\/tr>\n
Type 3<\/strong><\/td>\nThermoformed fiber, multiple heated molds<\/td>\nAbout 2 to 4 mm<\/td>\n<\/tr>\n
Type 4<\/strong><\/td>\nProcessed, meaning any type with secondary treatment<\/td>\nVariable<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Types 1 and 2 are dry pressed territory. Type 3 is wet pressing. Type 4 is whatever you add afterward, such as printing, coating, or die cutting.<\/p>\n

Suppliers quote their own achievable ranges, and they’re often tighter than the IMFA bands because equipment and fiber vary. Ask for the range your supplier can actually hold rather than a number from an industry chart. Our article on the 4 types de p\u00e2te \u00e0 papier moul\u00e9e<\/a> covers how we apply these categories.<\/p>\n

Finition de la surface<\/h2>\n

This is what most buyers notice first.<\/p>\n

Dry pressed trays show fiber. One face, the one that sat against the mesh, is smoother than the other. In good light you can see the grain. For an egg tray or an industrial insert, nobody minds. For a cosmetics tray sitting in an open gift box, it reads as unfinished.<\/p>\n

Wet pressed molded pulp comes out smooth on both faces, with sharper edges and finer definition. They can hold small logos, fine ribs, and tight radii that dry pressing would soften. That finish is also easier to print on and to label cleanly.<\/p>\n

If your packaging is opened by a customer, that difference is the whole argument.<\/p>\n

Wall Thickness and Protection<\/h2>\n

Thicker walls absorb more energy. That’s why dry pressed trays suit fragile items that take real handling, including eggs, glassware, and heavy industrial parts. The fiber compresses under impact and recovers.<\/p>\n

Wet pressed walls are thinner and denser. They’re strong for their weight and hold their shape well, but there’s less bulk material to absorb a shock. For a light product that needs a premium presentation, that tradeoff is fine. For a heavy product on a rough route, it usually isn’t.<\/p>\n

There’s a common mistake worth naming here: choosing wet pressing for packaging nobody sees. You pay for the finish and lose some cushioning at the same time.<\/p>\n

Detail, Draft Angles, and Tolerances<\/h2>\n

Dry pressed parts need more draft, meaning a more generous taper on the walls, so the part releases cleanly and nests properly. Fine text and sharp internal corners come out soft.<\/p>\n

Wet pressed parts hold tighter geometry with minimal draft, which matters when the tray has to locate a product precisely. If you’re designing a fitted insert for electronics or cosmetics, this is usually the deciding factor rather than appearance.<\/p>\n

Cost: Tooling, Cycle Time, and Unit Price<\/h2>\n

Three cost effects run in the same direction:<\/p>\n