hard anodizing / sulfuric / chromic / sulfo-tartaric
hard, sulfuric, chromic, sulfo-tartaric
Type of substrate:
industrial, medical, for the construction industry, for the food industry, for robotics
medium series, large series, small series, individual
Loose Bulk Goods
Small bulk goods of aluminium, which are not stackable (e.g. rivets, screws, lathe-cut parts) can be anodized as "loose goods” in a similar manner like at barrel galvanizing.
However, since the anodized layer has a very high electrical resistance and acts as an insulator, anodizing in a rotating drum is not possible. Aluminum small parts must therefore be clamped in suitable devices as bulk material and can then be anodized and optionally dyed in a dip dyeing process.
Due to this type of processing, however, visible contact points are inevitable, especially in the case of colored articles. If these bother, they must - as with the AI rivets shown here - be sorted out for rework. Depending on the requirements and geometry of the parts, this results in a reworking rate of approx. 10-20%.
Despite the sorting work, however, this method remains far less expensive than individual processessing. In addition, since small holes can not stick together (as possible when painting), it is not replaceable for many applications.