Just over two years ago, Bill Wanner and Payton Hage, owners of Wanner Engineering (Minneapolis, MN) and CEO / President, respectively, made the investment decision to purchase highly automated machining systems. The 25-year-old company needed the flexibility and productivity provided by such a system to outpace their competition and remain responsive to customers' delivery requirements. According to Hage, flexibility was a critical factor.

"Wanner Engineering designs and manufactures pumps for a variety of industries, used in all types of environments," Hage explains. "Our pumps are used in such applications as car washes, in trucks for lawn care and steam carpet cleaning, in cogeneration power plants for lime slurry, in submarines producing nuclear grade water by reverse osmosis. And, in machine tools for both low and high pressure applications, with diaphragm style pumps that handle coolants with particles up to 500 microns in size. They're used for pumping all types of fluids -- hot, cold, acids and corrosives, and thick suspensions. Consequently, pump components are made from cast iron, brass, hastaloy, stainless steels, aluminum and polypropylene, depending upon the application.

"We wanted the agility to be able to fill a customer's order for a single pump, when necessary, by machining all the needed components on a JIT basis. This could mean running an aluminum housing, followed by a stainless steel manifold, plus steel cylinders, cast iron cylinder housing and valve plate, and numerous other parts from any of the materials -- one right after the other."

The machining system Wanner and Hage chose was the Mazak Palletech Series, consisting of two horizontal machining centers and a 15-pallet part pre-staging, machine loading/unloading and transfer unit. They also specified that each machine be equipped with Mayfran International's (Cleveland, OH) ConSep 2000™ chip handling conveyor/coolant cleaning systems, which at the time was a new technology, having been introduced in 1996.

Payton Hage is pictured, left, standing by one of the Mayfran ConSep 2000 and AT Coolant Cleaner packages, holding a part typical of those that Wanner manufactures. The large dark blue unit behind the part is one of the Hydra-Cell pumps Wanner manufactures.

"We've worked with Mayfran in the past, providing pumps for many of their systems, so we were familiar with the operation of the ConSep," says Hage. "Its ability to handle a wide variety of chip shapes and volumes produced from different materials seemed the ideal option for our particular application. And, because the machining system operates with high pressure coolant flow, we also added bag filter units to clean the coolant."

For the most part, reports Hage, the machining system and the ConSeps have lived up to and surpassed their expectations. Except, that is, for one small detail -- although a variety of materials are used, the predominance of cast iron machining meant a large amount of small fines and superfines (below 50-micron size) were accumulating as sludge and clogging up the bag filters, restricting coolant flow and requiring frequent maintenance for cleaning.

"It was somewhat ironic and very irritating that the coolant system -- in particular the bag filters -- would disrupt our productivity," Hage remarks. "Our machine operators reported that the filters, when processing cast iron parts, would slime up in a matter of minutes. This may be slightly exaggerated, since they were responsible for maintaining the machines and replacing the filters, but not far from missing the mark...the productivity and flexibility we sought were lost to a large extent because of this sludge removal downtime."

Consider, for example, the blockage of coolant distribution channels that will restrict and reduce flow to tools and parts. This can result in chips not being properly flushed from parts and workholding devices, premature tool wear, inaccurate tool compensations, and higher temperatures that can work harden areas of the part. Eventually, the entire coolant management system will not function properly. Also, when chips, fines, and superfines accumulate in the reservoir, to the point where their volume displaces too much of the fluid, pumps cavitate and the coolant temperature elevates, resulting in evaporation and possible issues detrimental to part quality.

Fortunately, Mayfran shortly thereafter introduced the AT-Coolant Cleaner, an independent, maintenance-free, media-free coolant filter unit that easily integrates with the ConSep system. The new filters provide 10-15 micron coolant cleaning, in addition to the ConSep 2000's preliminary 50-micron separation, through a mechanical process -- there are no bags or other media to purchase, clean, replace, or dispose of. Particles and sludge, separated from the coolant, are carried away by conveyor to a scrap hopper.

Once installed, the CS-2000 and AT-Coolant Cleaner combinations have virtually eliminated migration of process-harmful contaminants to the "clean side" of the process, a critical element in the performance equation of today's high pressure operations.

For Wanner Engineering, this means unrestricted flow rates running at variable rates of up to 15 gpm and in pressures from 800 to 1000 psi, plus less wear on machine tool components, workholding devices and tools, and longer coolant life. In addition, the company's waste stream liability has been significantly lowered and the potential for spills and overflows has been greatly reduced.

"We've been operating the machining cell for about 18 months now, with the AT-Coolant Cleaners on the job," notes Hage. "In that time the system has not had to be shut down once for cleaning of chips or sludge. This performance has exceeded our expectations."

The standard Mayfran ConSep 2000 system consists of a hinged and perforated steel belt conveyor for larger chips and strings, plus a lower drag conveyor and filter drum for removal of fines. Large chips and strings are simply carried away to the chip discharge chute by the steel conveyor as coolant flows down to the lower area containing the drag conveyor and filter drum. The coolant is maintained at a level below the height of the steel conveyor, helping to drain residual fluid from chips, while minimizing the problem of floating chips.

The integral ConSep filter unit, different than the AT-Coolant Cleaner filter, segregates particulates to 50 micron nominal and features a self-cleaning, pressurized backwash for the drum's poly fiber media. After the backwash cycle, the lower conveyor then picks up and carries off the fines. The over/under location of the two discharge chutes allows chips and fines to be collected in the same hopper. The pressurized backwash system for the mesh filter eliminates downtime for manual cleaning.