Introduction

Certain application and system requirements must be observed when processing IGP fine-textured coatings:

VR 214 informs the processor about the process parameters that have a significant influence on the coating result. In principle, IGP fine structure powders are very application reliable and ensure a uniform structure formation within a wide range of coating thicknesses. IGP fine-textured powder coatings are labelled with a "1 or 4" in the third position of the IGP product code (e.g.: 561, 591,...). The gloss is labelled in the fourth position as "M" for a matt and as "T" for a deep matte gloss (example: 381M, 561T,).

Structural training

In principle, IGP fine structure powders produce uniform surface structures within a wide range of layer thicknesses. In order to achieve a uniform texture, Film thicknesses of 60 - 90 µm are recommended as an average measurement and medium high-voltage settings between 60 and 80 kV should be used. Settings greater than 80 kV can have a negative influence on the coating result, especially at shorter spraying distances. Limiting the spray current (µA) is not absolutely necessary, but can contribute to the formation of a more uniform structure. A value <10µA is recommended.

In order to minimise the influence of the high voltage and Film thickness on the structure, the use of ion-leakage rings (low-ion charge) is recommended. Film thicknesses of up to 150 µm can be achieved when coating with ion-leakage rings without noticeable changes to the surface. The use of ion-leakage rings is particularly recommended when components are coated manually or objects with difficult geometries need to be coated. During coating, the spraying distance should not be less than 200-250 mm. Smaller distances may result in visible streaking on the surface. A greater distance must be maintained, especially with IGP coating powders with pearl mica effect, to prevent streaks and cloud formation. Please also refer to processing guideline VR201.1 (Processing of IGP effect powder coatings) and processing guideline 213 (LivingSurfaces). When processing fine texture powders, it is important to avoid large differences in layer thickness on the components. This often occurs during manual pre- and follow-up coating and on outer edges (picture frame effect). In order to reduce differences in coating thickness during pre-coating and subsequent automatic final coating, it is advisable to carry out tests before starting the coating process to determine the areas that require pre-coating.

In this way, double coating of parts of the object can be avoided. With light, red, yellow and orange shades, complete coverage of the substrate is not always guaranteed with the recommended layer thicknesses. A pre-coating in the corresponding shade is recommended to cover the substrate (2-layer structure).

Mounting the parts

The mounting of the workpieces must be determined before coating (horizontal or vertical). The distances between the coating objects within the hanger as well as the distances between the hangers should be as small and even as possible. If the distances between the hangers are large, it is advisable to switch the guns on and off automatically via a parts detection system.

Earthing

When processing fine-textured powder coatings, particular care must be taken to ensure sufficient earthing. This measure contributes significantly to a uniform layer thickness and texture embossing.