Save weight, time and cost at the same time

11 / 2013 - As automotive interior trim level offerings increase, foam-backed instrument panels laminated with real or artificial leather pose particular challenges. The PURe Skin Technology which is exclusively offered by FRIMO saves weight, time and money at the same time.

This SPE award-winning process involves using a silicone skin that initially serves as a skin substitute. The re-usable PURe Skin is removed once an instrument panel substrate is backfoamed. The visible leather surface of the instrument panel is then press laminated in place of the PURe Skin.

In addition to innovative technology and rigid safety requirements, sophisticated interior design plays an increasingly important role in today's automobiles. For an attractive vehicle interior leather and artificial leather are used as premium decorative surface materials.

Leather skins have a specific wall thickness and stitching that require the geometry of the backfoamed polyurethane to be modified. In the past, this required separate undersizing tools as well as an under skin (thermoformed, spray, or slush skin) to remove the backfoamed part. This extra skin layer significantly compromised haptic properties. The PURe Skin technology eliminates these disadvantages and also offers additional advantages in terms of production flexibility.

PURe Skin – a skin substitute made of silicone

The PURe Skin making process involves using a relatively simple, closed tool to first create a temporary skin made of a two part silicone elastomer. This skin has exactly the same dimensions as the leather skin to be applied later. In addition to the wall thickness of the leather and a spacer fabric (where applicable), these dimensions also include the rear seam. In place of the previously mentioned secondary or under skin, the PURe Skin is backfoamed and is then removed again. This creates an exact undersized surface subsequently laminated with the leather skin. Complex geometries with undercuts present no problems. With a wall thickness of approximately 1 mm, the PURe Skin has an elasticity of more than 200 percent, without permanent deformation. PURe Skin technology also enables the realization of geometries for variants, e.g. for the application of special functional or design elements.

Because a single skin can be reused more than 20 times according to experience, a closing frame is sufficient for the manufacturing of the PURe Skin. This increases the cost efficiency of the process. Large opening areas allow excellent accessibility for handling and tool cleaning. The tools, which are tempered on both sides, are machined from aluminum block material and kept closed using threaded rods.

In terms of storage and shipping, there are no special requirements for the skins. They are insensitive to temperature variations and buckling, and can be stored, stacked and transported without contour support. The PURe Skin has only to be protected against dirt, static buildup and mechanical tearing caused by sharp or pointed objects.

Backfoaming PURe Skin

The PURe Skin is inserted into the foam tool, without preheating, in place of a regular skin (thermoformed foil, spray, or slush skin) and then backfoamed like any other conventional decorative material. The load time is similar to that of conventional skins. As soon as the foaming process is complete, PURe Skin can be easily and manually separated from the urethane foam surface.

Then after additional curing time, the components can be laminated with the leather or artificial skin. As PURe Skin has the same geometry as the leather skin, adding the leather produces the desired surface dimensions. Only PURe Skin comes into contact with the foaming tool during the foaming process. This prevents any problems due to potential contamination by release agents, as sometimes occurs with undersized slush skins, for example. Before laminating, spacers nd/or inserts such as fiber optics can be applied to the foamed component.

Lighter components thanks to PURe Skin

In addition to the advantages mentioned above, eliminating the previously required redundant under skin layer reduces the overall weight of the instrument panel.

Flexible production

Because no special under-sizing tools are required to produce substrate foam sandwich for leather wrapping, unique leather components can be produced using standard tools within the normal production process. This allows for “on the fly” production line changes to produce both synthetic skin as well as leather surfaces.

Cost considerations

Costs can be reduced considerably by eliminating additional models, different tools needed such as foam tools, nickel shells or thermoforming tools as well as tool carriers. Costs for necessary set up and production for the under skins can be completely eliminated. Also after having considered all expenses related to the PURe Skin application, there is a remarkable cost saving potential that individually depends on geometry, volume and specific project requirements.

FRIMO range of services

For a PURe Skin project, FRIMO will develop a cost/benefit analysis during the pre-engineering, provide a design feasibility study part geometry, manufacture the tool and systems technology for the series, validate the tooling at the FRIMO TechCenter, and supply PURe Skins to the customer as an approved auxiliary production aid.

Contact for further information and documentation

FRIMO Group GmbH
Martina Schierholt
Hansaring 1
D-49504 Lotte

Phone.: +49 (0) 54 04 / 8 86 - 1 57
Fax: +49 (0) 54 04 / 8 86 - 51 57
E-Mail: schierholt.m[at]frimo.com