Printed TPU Lattice: Can It Replace Foam?

Foam is cheap, and that's the hard part about replacing it. A printed TPU lattice earns its place where foam can't do the job, like a custom shape or soft and firm zones in the same part.

Can a Printed TPU Lattice Replace Foam in a Product?

Yes, at low volumes and where the shape or the feel has to be tuned. It won't beat cut or molded foam on cost per part, so the case has to rest on fit and performance.

An r/AdditiveManufacturing poster asked for "real talk" on elastomer lattices for a consumer foam product at roughly 100 to 1,000 units.

How a printed TPU lattice gets its stiffness

The material sets the range. The geometry sets the feel. A 2023 study in Polymers tested printed elastomer lattices built from Kelvin cells. Its uniform lattice in a 95 Shore A TPU measured 2.17 MPa structural stiffness, against 39.1 MPa listed for the solid material, at about 23% volume fraction. A version with struts 50% thinner at the bottom compressed further and bottomed out sooner. The study's TPU parts weren't powder-printed, so treat the numbers as a trend, not a spec.

That's the lever foam doesn't give you. Change strut size across the part and you get a soft heel and a firm edge from one material. The same study found the stiffer TPU absorbed more energy before bottoming out, while a much softer elastomer did better on low-energy comfort.

For how thin printed sections behave when they flex, our posts on minimum wall thickness for a flexing nylon part and walls or ribs for repeated flexing are a starting point, though TPU behaves very differently from nylon.

Before you swap the foam out

Price the surface, not just the volume. Our printing quote is built from "bounding box, surface area and solid volume," and a lattice is mostly surface. It'll weigh far less than a solid part, but don't expect the price to drop at the same rate.

Leave the powder a way out. Unfused powder has to come out of every cell, so tiny, dense cells are a risk. Ask us about cell size when you quote.

Then squeeze real samples. A stiffness number won't tell you how a grip or pad feels after a week of use, so print two or three cell sizes and compare them by hand.

TPU at DigiForge

TPU is on our Materials page for "flexible printed parts, gaskets, grips." Upload STL, OBJ or 3MF; the engine checks watertightness and triangle count automatically, so keep heavy lattice meshes clean.