Burscheid, Germany-- With two-colour slush skins, in PVC or TPU, automotive interior systems supplier Johnson Controls says it now offers another technology for the surfaces of automotive interiors. This extended in-house competence gives carmakers a variety of options, in harmonised colour, grain and shine of car interior components, whether they are slush or thermoformed skins, said the interiors expert.
"Slush skins meet the highest quality demands for colour characteristics and shine in the automotive industry. At the same time they also create varied design options as complex geometries with extremely precise large undercuts and even small radii can be produced," said Han Hendriks, vice president for global interiors development at Johnson Controls Automotive Experience, in a company statement.
"In addition, we are now able to produce two-colour slush skins in a single production step. Up to now, this was only possible in a single colour, which restricted the way the process could be used," Hendriks said.
Slush skin technology shapes a part using a galvanically produced mould. To make an instrument panel, a bath filled with slush powder is connected to a galvanic mould that is heated up to 230°C. By rotating the bath with the galvanic mould, the coagulating PVC (polyvinyl chloride) powder is distributed over the grained tool surface. The quantity of powder that sticks to the mould is determined by precisely adjusting temperature, rotation and time.
When the powder has settled on the heated inside surface of the mould, the mould is removed and the melted PVC powder coagulates in the tool, forming a homogeneous skin. After cooling to around 50°C the skin can be removed from the mould.
Advantages of slush skins include contour-specific reproduction, and distortion-free depiction of a grained surface with even thickness distribution. "Later when the substrate is coated, for example on an instrument panel blank, this results in an extremely precise fit, and the even material thickness ensures a pleasant touch also in such critical areas as undercuts and tight radii," said Hendriks.
Johnson Controls said slush skins, usually made from PVC, but sometimes also from TPU (thermoplastic polyurethane elastomer) are very versatile. Different shine levels and 'haptic' effects can be produced.
The exact reproduction of the surface of the galvanic moulds even enables slush skins to imitate decorative stitching realistically. The technology is also excellent in terms of colour consistency, resistance to scratches and aging, and not least in the low emissions it generates.
To be able to offer two-colour slush skins, Johnson Controls is using masking technology, with the tool partially covered by a mask. A robot sprays a 0.6 mm powder layer on the uncovered areas of the mould. Then the mask is removed and the rest of the process is carried out as usual.