There's more astonishing 3D printing material coming from the banks of the Rhine River in an industrial part of Cologne, Germany.

Kai Parthy, a former shoemaker in a Leipzig theater, technician in an underground music club in Cologne, truck mechanic and the materials engineer behind innovative materials like BendLay, Laywoo-D3 and Laybrick, has unveiled LAYFOMM 40 Filament.

This time, the material features a property Parthy says exhibits viscoelasticity. While elastic like rubber, it features a damping effect that might prove ideal for a variety of 3D printing applications from sponges to foams to soft tissues and inner shoe soles.

While polyurethane filaments like NinjaFlex feature a similar property, Parthy says the elastic effect of LAYFOMM includes a retardation element, allowing it to reclaim its shape after a couple seconds or up to minutes and it works at room temperature.

Parthy says viscoelasticity is different from memory-effect in that LAYFOMM exhibits a spring and damping effect, whereas simple rubber is a "spring only" material.

Kelvin-Voigt viscoelasticity diagram

Viscoelasticity is displayed in materials which have both viscous and elastic characteristics when undergoing deformation. While a purely viscous material like honey resists shear flow and strains in a linear fashion under stress, and elastic materials strain when stretched and quickly return to their original state when stress is removed, viscoelastic materials demonstrate both properties and react to strain in a time-dependent manner.

The Kelvin–Voigt model, also known as the Voigt model, is demonstrated when a Newtonian damper and Hookean elastic spring are connected in parallel. This explains the "creep behavior" of such polymers.

Parthy says the viscoelastic properties of LAYFOMM may be determined by using different fluids after a first step of rinsing a printed object in tap-water. He says the ultimate property set of LAYFOMM can be manipulated by soaking printed objects in oils, solutions of various alcohols, in low concentrations of glycerol and in solutions of different salts to achieve the desired results.

After printing on a standard 3D printer, an object is rigid, but after a few days in room-temperature conditions, LAYFOMM begins to fully display its viscoelastic properties.

If you'd like to try LAYFOMM, it's available from Ebay, Matterhackers (free US shipping) and Formfutura.