Managing the plating baths in which parts are immersed is a costly part of metal finishing. Companies must make sure the amount of chemicals in the baths is just right in order to plate high-quality parts. Then, after the plating solutions are spent, platers must properly dispose of them.

To put a plug on costs, plating companies are finding ways to better maintain these baths—from turning to new filtration systems and employing automated chemical feeders to using acid bath extenders.

For example, Michigan-based Meridian Automotive Systems installed a new filtration system that utilizes an absorber polymer to purify the company's bright-nickel-plating baths. The result was significantly less filter changes.

"We used to have 208 filter changes a year when we did carbon treating every four months," says Bill Slater, plating manager. "Now we have only 64 and no batch treating. That is a filter change every 45 days, compared to every two weeks with the previous filter system."

Indeed, before employing the new system, filtration was often messy and lengthy because of the huge volumes of nickel the company uses. Plating 6,000-6,500 truck bumpers everyday, the company manages four, 10,000-gallon bright nickel tanks on two automated lines. It also produced a lot of sludge—a substance left over after water is treated with chemicals that neutralize harmful chemicals.

Using the new absorber polymer unit, which filters one tank each day for 9.5 hours, Meridian has been able to send 13,760 lb. less sludge to the landfill a year.

The new filtration system never disrupts production because it continuously sends part of the bright-nickel-plating bath to treatment, boosting efficiency and reducing costs. It has also lowered solution loss; the tanks lose about 42 gallons of nickel-containing solution per day because the absorber polymer must be rinsed after each regeneration cycle. More solution was wasted during the treatments and filter changes of the old system.

The new system has eliminated the need for batch carbon treatments, which had a total annual labor and material cost of about $2,600 per tank and another $5,200 for filter changes. Now, filter changes cost only $83 per change, for a total of $5,312 per year for all the bright-nickel-plating tanks.

Connecticut-based Seaboard Metal Finishing is also enjoying significant savings from learning to manage its baths better. Seaboard switched from manual to automatic chemical additions, saving almost $14,000 annually in labor alone.

The company plates parts—offering nickel, tin, black chrome, antique and other finishes—for a wide range of industries, including automotive, marine, military, electronics, hardware and telecommunications.

Its automated chemical addition system makes sure that just the right amount of chemical is regularly added to Seaboard's tin- and nickel-plating baths to ensure consistent plating. For example, "the nickel plating baths are controlled with chemical feeders, which does the proper amount of nickel brightener, thereby reducing the potential for too much chemical addition that can result in ductility issues as well as wasteful use of chemicals," says Steve Tarantino, president of Seaboard.

Before using the system, "we used to buy 400-500 lb. a week of potassium stannate," says Tarantino. "Now we buy 100 lb. a month. That's only because we have control of the metal through these chemical feeders. We've saved a tremendous amount of costs associated with that." He estimates that cost savings range from $250-300 per week.

The chemical feeders not only save money but also keep product quality high. "Maintaining the proper brightener adds with a brightener feeder has reduced not only our chemical costs but also the amount of rework," says Tarantino.

The right chemistry has also made a difference at North Carolina-based Amplate, Inc., a job shop plating company. President David French learned about a reagent chemistry that could prolong the life of Amplate's acid baths.

The company began using the PRO-pHx acid bath extender, which only calls for simple filtration, in its acid baths for many plating operations—such as its zinc, electrolytic nickel, electroless nickel and decorative chromium plating lines. The result was unusual longevity—many acid baths have passed the 20-month mark and still remain strong.

In fact, since starting to use the acid bath extender in Nov. 2000, the company has not needed to dump any acids.

For example, the acid bath extender has restored the chloride zinc-plating bath, which uses hydrochloric acid, more than 34 times in 20 months. This is no small feat considering that the tank is used for more than 60 hours per week. When the acid bath extender is added, the spent acid becomes as effective as if it were only two-days old.

Due to the acid bath extender, the company's black oxide tank is also performing as a two-day-old acid—when in fact, it's been using the reagent chemistry for over 23 months and is in use for more than 40 hours per week.

The hydrochloric acid tank on the zinc line has benefited from the acid bath extender as well. Previously, the tank had to be dumped every two weeks. Now, it works for five months straight without requiring additional acid extender chemistry.

Amazingly, the return on investment on the acid regeneration chemistry was two weeks. "We saved a ton of money and significantly reduced sludge shipped to the landfill," says French. The company previously disposed of more than 11,000 lb. of neutral salts from acids, but last year, acid disposal was nonexistent. In fact, using the chemistry has generated over $25,000 in savings annually.

Sources: Long Live Acid Baths!
Beverly A. Graves
Products Finishing, Nov. 8, 2002
http://www.pfonline.com/articles/110205.html

Saving Valuable Bath Chemicals
Beverly A. Graves
Products Finishing, Dec. 2, 2002
http://www.pfonline.com/articles/web120201.html

Shining Up Bright Nickel Plating Baths
Beverly A. Graves
Products Finishing, Dec. 15, 2002
http://www.pfonline.com/articles/120201.html