Enhancing Aluminum Vibratory Finishing: A Case Study

The Challenge

A client specializing in third-party surface treatments contacted us with the need to improve the quality of vibratory finishing for aluminum parts. Specifically, the client brightens various types of aluminum (both extruded and die-cast) using a vibratory finishing machine. This machine treats the parts with the aid of steel spheres, to which a specific acidic brightening detergent is added.

At the same time, the client requested that the new product be phosphate-free, as they wished to move towards a formulation with a lower environmental impact than the current one.

Our Solution

Aluminum vibratory finishing with steel spheres is a process particularly suitable for conferring a high-quality surface finish to a large number of small parts, treated inside vibratory finishing machines.

This type of process consists of cleaning and smoothing the surfaces to be treated, due to the mechanical action produced between the parts rubbing against each other in addition to that produced by the steel spheres.

The rubbing action significantly reduces substrate residues (roughness), thus making the treated surface mirror-like.

This action is always supported by the action, very important, of a specific chemical compound, commonly called a brightener, which has the function of cleaning the surfaces, lightening them as much as possible and lubricating the steel spheres so that they can work on the surfaces without scratching them.

Specifically, after a first phase in which we assessed the feasibility of what was requested by the client, we contacted our suppliers, expressing our willingness to experiment with innovative solutions.

After a series of preliminary tests carried out in the laboratory and tests carried out directly on the client’s plant, testing the new raw materials proposed to us, we were able to formulate a product for the brightening of aluminum more effective than the one previously used and totally free of phosphates.

The new acid brightener was then balanced in such a way that the spheres, appropriately lubricated, work uniformly on the surfaces, thus reducing their roughness and making them smooth and shiny.