A company had a process where they were etching metal components with an acid bath.  The system consisted of four baths where the metal parts would be dipped.  The four baths consisted of a wash, rinse, acid bath, and rinse again.  The automated system was contained inside an enclosed booth; and, once the parts were placed inside a 24” (610mm) X 18” (457mm) basket, a sliding door was closed to initiate the operation.  The timing sequence consisted of the basket being dipped into each bath for a certain length of time.  Between each bath cycle, the basket would be raised above the solution, and an open pipe blow-off would remove excess liquid from the part with compressed air.   They complained that the parts were not getting dry enough, and cross-contamination was causing process problems.  The acid bath was becoming more neutral and the effectiveness of the etching was being sacrificed.  The rinse water was becoming more “soapy” after the cleaning bath and more acidic after the acid bath.  Overall, they had to replace every one of the bath solutions which caused shut-downs and extra expense.

From similar applications, I was able to recommend a great solution.  Because of the acidic solution and corrosive environment, I recommended two stainless steel Super Air Knives, model 110024SS.  They are manufactured in 303 stainless steel.  EXAIR also offers 316 stainless steel as well as PVDF for more acidic or caustic etching.  Instead of using the open pipes to blow off the parts, the customer could replace them with the Super Air Knives.  They can easily be mounted above the front and back of the basket, blowing at a downward angle toward the dip tank.  The two Super Air Knives would remove the liquid solution from the parts as well as the basket to put back into the same dipping tank.  The more solution that is removed, the less liquid that will transfer from one solution to the next; thus, reducing cross-contamination dramatically.

After installing the model 110024SS Super Air Knives in their system, they started to see a vast improvement in their etching process.  The etching acid was able to be used roughly 40% longer as compared to the prior method.  As an added feature, the Super Air Knives decreased the time to blow off the parts as they can be adjusted for optimum cleaning.  Less waste and faster production times were how the EXAIR Super Air Knives helped the customer above.  If you have a similar application and want to discuss how we can improve your dipping process, please speak to one of our Application Engineers.  We’ll be happy to help.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb