Mechanical Pre-Treatment

Mechanical pretreatments remove rust, scale, or similar solid impurities. By the simultaneous degreasing workpieces whose adhesive strength is improved for subsequent coating. They generally increase the surface active, since the surface roughness is increased.

Typical methods are sandblasting, sweeping and sanding.

Chemical Degreasing

The workpieces can also be chemically degreased before coating. This is done in two separate cabins for aluminum and steel with aqueous cleaners (supplier NABU).

Depending on the requirements for corrosion protection class and area of the workpiece, the cleaning of the surface is additionally connected to the building of a new, specific surface structure, such as a phosphate or a passivation layer.

Applying conversion layers

The application of a conversion layer connects to the degreasing. Although a pure degreasing enough for a clean surface and most of the connections of the paint or powder already works better mechanically , and thus has a significant impact on the corrosion protection.

A conversion coating improves the corrosion protection again significantly. According to the material, the subsequent step is pickling, phosphating or chromatizing.

Typical procedure for the application of conversion coatings are the phosphating on steel, the pickling on galvanized steel , pickling and passivation on aluminum. Due to the increasing constraints on the chromium-containing layers chrome-free methods are used in the LZR only. For aluminum workpieces pickling and chromate passivation is done by an automatic applicator through which a perfectly uniform surface treatment can be guaranteed.
 

Flushing

After each chemical pretreatment step the rinsing process is of crucial importance . Usually it is necessary to perform one or more rinsing steps to avoid buildup. The most recent of a new rinsing step is therefore carried out with deionized water.

 

Intermediate drying

Before application of the powder, the surface of the workpiece must be absolutely dry. In a dryer especial for retained water, the workpieces are dried immediately after the chemical process.