Cleaning of dies at Hydro
The extrusion of aluminium requires regular cleaning of the dies. Cleaning of the dies involves two steps. First, the dies are immersed in a heated solution of NaOH for a certain period of time. During this process, the aluminum that is present will dissolve and thus the die is cleaned.
In the second step, the die is cleaned with water to wash out as much of the remaining pollution as possible.
This is a relatively dangerous job, given the presence of NaOH, and the release of H2 gas during the process. Furthermore, unpleasant fumes will be released throughout the process.
Therefore, PCA has developed a system in which the dies are treated in closed process baths which are in underpressure. As a result, hardly any fumes are released into the environment. Additionally, a relatively high flow rate of air ventilation is applied in order to limit the H2 concentration and prevent the risk of explosion.
Another advantage of the PCA process is that the operator does never come into contact with NaOH. The process baths are completely empty when the operator places the dies in the baths. The cover will only open after all steps have been completed (including the rinse cycle) and the operator can remove the molds from the process bath.