Modern metal plating is a process that was developed in the early 1800s. It’s now widely used for coating everything from chrome bathroom fixtures to parts used in the aerospace industry. Metal plating is the process of putting a thin coating of metal over another object (the work), which is also often metal. The coating metal is chosen for its beneficial properties based on the specific application. Sometimes it’s purely decorative, for example gold or silver plating on jewelry. Sometimes a plating material is chosen for a combination of reasons — perhaps because it’s both decorative and protective, as in many chrome applications. And there are many other reasons you might want something to be coated with metal.
AOTCO Metal Finishing, Inc., is a supplier of specification plating and electropolishing services in Billerica, Mass. In business since 1975, AOTCO provides specialty plating to the aerospace, optical, telecommunications, medical, and electronics industries. Its customers include Ball Aerospace, Boeing, Lockheed Martin, Northrup Grumman, Raytheon, and Rolls Royce, among others.
Although it does work for some big companies, AOTCO is a relatively small company with about 45 employees. The company works extensively with gold, silver, nickel, tins, and coppers.
“We do just about any kind of electroplating and electroless nickel plating,” said Tim Tripodi, Facilities Manager for AOTCO. “Basically what we do is we put metal on metal.”
The electroplating industry uses copious amounts of water. Depending on what part of the process the water is used for, it can be contaminated with heavy metals, harsh chemicals and acids, oil and grease.
“The water cleans the material before you plate it and it cleans it after. It’s kind of like painting. If you don’t clean that surface, the plating won’t stick to it,” Tripodi said. “Before you go in the bath you go in the water to rinse off any of the acids that you might have used to clean the surface, what we call activating the surface.”
AOTCO uses about 8,000 gallons per day of water for its various cleaning, plating, and rinsing processes. Periodically, the baths and rinsing basins are drained into small pits. The spent fluid is then transferred to a larger pit to be treated. Some of the water may be gravity fed into the larger pit areas, but most of it is pumped.
There was a time when the plant was configured so all of the spent liquid was gravity fed, but after a fire many years ago, the plant was rebuilt and configured to primarily use pumping rather than gravity.
“Right now I have probably nine pumps working,” Tripodi said. “Generally I have a Perfecta® pump in a small tank that receives all this water and it’s pumped to another larger pit where the water is treated.”
Different areas receive different qualities of water depending on what’s being plated, but generally the water is aggressive — sometimes extremely so. Sulfuric acid, hydrofluoric acid, and phosphoric acid are commonly used in the plating process.
“Those are the three — if they’re real strong they’ll go after everything in the pump” including the plastic covering, Tripodi said.
He explained there’s not a good way of knowing the exact potency of the water once it’s drained into a pit where it may mix with other spent liquid. Each job is unique and has its own learning curve. A particular job may have a new kind of part that suddenly starts dragging more acid than normal into the rinse and unexpectedly subjects the pump to harsher chemicals.
“There’s not a lot you can do with that other than try to dilute it more,” Tripodi said.
Not only do the pumps have to hold up to harsh chemicals, they also need to be a sturdy, reliable, all around pump.
“Most of them do have some sort of head pressure on them. There’s a couple that have more head pressure on them than others. They’re pumping up probably 13 feet and then quite a distance horizontally,” Tripodi said.
Moving the highly caustic, often hot, water would be a challenge for any pump. AOTCO started using the BJM Perfecta® pumps about 24 years ago. They have stuck with them because they performed better than anything else on the market and continue to do so. To some extent, plating technology in general, the AOTCO plant, and the ingenuity used in building Perfecta® pumps, have grown up together.
Although the general concept of electroplating hasn’t changed much from when it was first invented, in practice there have been significant improvements to the process in terms of the technology and chemicals that are used.
These improvements have placed a corresponding and increasing demand on the equipment — namely the pumps that are in continual contact with the aggressive liquids involved in electroplating. As the electroplating process has improved, the Perfecta® pumps have had to keep pace.
“I started using the Perfecta® pumps probably 24 years ago,” Tripodi said. “They have increased the material that the pumps are made of. They make them now with stainless steel components and titanium components.”
AOTCO sources its pumps from Maltz Sales, headquartered in Foxboro, Mass. Maltz offers a comprehensive line of BJM Pumps, but for this job, the Perfecta® Series pumps continue to fill the bill.
“They’re a good fit for this. They’re corrosion resistant, they’re submersible, and they have a float on them,” said Skip Bowen, sales person for Maltz. Bowen, who is the representative for the AOTCO account has been with Maltz for 13 years and feels confident in continuing to recommend the BJM’s Perfecta® Series pumps.
“They’re a very good pump company. They respond well, they’re a good price, and they’ve got a good inventory. We stock these submersible Perfecta® pumps, and we sell quite a few of them to AOTCO and several other companies,” Bowen said.
In addition to the heavy duty 304 and 316 stainless steel and titanium options, some of the specifics that make the Perfecta®Series pumps especially well-suited for this and similar applications:
- Only Electric Submersible Pump in the world that has its entire motor encapsulated in NORYL®.
- Virtually unbreakable.
- Compact and lightweight at only 13.5 lbs.
- Never rusts. Excellent resistance against acids, alkalis (Consult chemical resistance chart for compatibility between pump materials and liquid before operating pump.)
- On/off mechanical switch is easily adjusted to provide level control and to eliminate unnecessary running.
- Two discharge ports: one 1 ¼ in. inside threaded connection and one 1 ½ in. tapered hose connection delivered with each pump.
- Thermal breaker incorporated in motor windings shuts off power before over heating due to locked rotor or long periods of running dry (130oC).
- For permanent installation temperature not to exceed 135oF.
- For intermittent use submerge less than 20 minutes in 195oF maximum.