Improving Metal Pretreatment

Improving Metal Pretreatment

Question:

We are one of the leading two-wheeler manufacturers in our country and produce more than one million bikes a year. We have four conveyorized paint lines for metal parts painting. I am interested in knowing more about cleaners used in metal pretreatment. My question is as follows:

Presently our cleaner baths are dumped periodically and fresh baths are prepared once the bath’s oil content reaches 3,000 ppm. This procedure involves cost and environmental concerns and requires too much down time for the preparation of the new cleaner bath. I would like to know about the availability of a cleaner whose constituents can be analyzed and whose life can be extended as much as possible, if a proven mechanism of oil skimmers/sludge separators are in place. I would be thankful if you could help us locate chemical and equipment suppliers who are able to provide this information. R. K.

Answer:

There are alkaline and detergent cleaners commercially available whose chemical and physical properties can be analyzed and controlled instrumentally. There are also skimmers and separators available that will extend cleaner bath life. Both these technologies are well known.

It is the policy of the Painting Clinic column to remain unbiased and not recommend specific equipment and material suppliers. I don’t get many “free lunches” by doing that, but as my Dad used to say there really are no “free lunches.” Instead, I will recommend that you peruse the pages of Products Finishing 2003 DIRECTORY & TECHNOLOGY GUIDE. Suppliers of Cleaning and Phosphating Equipment are shown on pages 324-327. Suppliers of Cleaning and Phosphating Chemical Feeders are shown on page 324. Suppliers of Cleaning Chemicals, aqueous are shown on page 327-329.