Pump/Filter Unit Eliminates Sump Clogging Problems

CSI Manufacturing (Southboro, Massachusetts) is a Swiss CNC screw machine shop specializing in high precision components for fluid controls, aerospace, weapons and telecommunication devices. These products are fabricated from metals such as steel, brass and aluminum.

Maintaining an intensive production schedule-the company operates 16 CNC machines for more than 20 hours per day, 7 days per week-presented the shop with some nagging operating problems. Because of the volume of relatively small parts running steadily in the machine, the concentration of small chips and fines in the oil increased rapidly. Specifically, chips were entering the gundrills, which compromised the parts’ finish and increased tool breakage, leading to unacceptable reject rates and machine stoppages. A subsequent cleaning of the machine resulted in further downtime issues, putting additional burdens on the housekeeping crew.

To address the problem, Steve Doody, president and founder of CSI, purchased the PFA-1002 pump/filter unit from Keller Products (Acton, Massachusetts). This system can be arranged and operated while the machine is running.

The system is mounted in a welded aluminum frame and is fixed to a 20-inch by 30-inch cart. It contains no electrical components and also features a high capacity bag filter, which removes chips and sludge as fine as 5 microns. The pump is capable of delivering up to 20 gpm of clean oil back to the sump. Driven by compressed air, the pump is inherently fireproof.

The unit has the capability to clean suspended solids and settled sludge from a sump in 30 minutes or less, and it eliminates the need to pump out the machine tool. The dirty oil is pulled from the sump via the 1 1/2-inch inlet hose, and it is then strained by the bag filter and continuously returned to the sump. The force of the clean discharge can be used to scour the bottom of the sump to return settled solids for pickup by the inlet line. If the bottom of the sump is particularly dirty, the machine tool can be idled briefly so as to clean the sump. The sump is never emptied, and the machine tool can run for extended periods without additional maintenance.

After using the system, Mr. Doody reported that the problems associated with having solids in the sumps were virtually eliminated. CSI accomplished this by operating the PFA-1002 for a few hours per day, once a week to clean each of its 16 sumps. As a result, Mr. Doody says, "Machines can complete their scheduled runs unattended, while tool life has been extended."

The company incorporates the PFA-1002 for other applications as well. The pump/filter unit removes suspended solids from the oil reclaimed from the chip spinner, which is typically loaded with fines. The self-priming air diaphragm pump allows operators to pump the oil (collected from the chip spinning process) into a 55-gallon drum. The drum can then be moved throughout the shop to top off machines as needed.

"This exemplifies the application of lean manufacturing initiatives-specifically, the elimination of non-value-added time," Mr. Doody says. "The units have increased shop throughput, reduced various problems relating to part finishes and improved overall shop cleanliness and working conditions."