Founded in 1967, Conval, Inc. (Somers, Connecticut) manufactures high-pressure globe valves, which are mainly used in the power generating industry. The valve bodies are machined primarily from steel forgings, as well as aluminum, bronze and Stellite on 20 CNC machines that operate during two shifts. Because the shop has been busy over an extended period of time, Roger Poirier, shop manager, has been evaluating all areas of operation to find possible gains in productivity.
Contamination of the coolant had been one source of continuing production problems. High levels of tramp oil and solids in the coolant flooded the working part, in turn causing rapid tool wear.
"The rapid tool wear required frequent machine adjustments during a run to maintain the company's dimensional specifications," explains Mr. Poirier. "Even with these adjustments, the amount of rework on parts that were not within the desired specification range was bogging down our delivery schedules. In addition, we were pumping out and changing our sumps every 6 weeks."
With mounting issues such as the reduced throughput on the machines and the loss of machine time, the company decided to address the contamination problem. The company's coolant supplier referred Mr. Poirier to Keller Products, Inc. (Lexington, Massachusetts), a provider of sump-side coolant cleaners. After surveying the shop, a Keller salesman recommended the Model 315, one of the company's five standard portable pump/separator units. This cart-mounted unit can clean a typical 60- to 200- gallon sump in a few hours, and it can then be relocated and set up at the next sump. The manufacturer recommends that each sump be treated once per week. Because the Model 315 has the capability to treat two sumps within an 8-hour shift, one separator can maintain the cleanliness of the coolant in ten or more sumps. Keller says its separators incorporate self-priming, air-operated pumps (no electric); a bag filter to remove floating solids that enter the separator with the oily coolant; and customized permanent oil separator elements.
After purchasing the unit, Mr. Poirier describes the results as dramatic. "On the first two machines, we removed 2 to 3 gallons of tramp oil in a few hours," he says. "The bag filter removes the fines associated with machining forged material."
"We are currently approaching 9 months with coolant in the sump, and there is no indication as of yet that the coolant will need to be changed any time soon," continues Mr. Poirier. "Tool life has increased, while the need to make machine adjustments during a run has decreased. Additionally, rework because of coolant issues has been virtually eliminated." Mr. Poirier goes on to mention other noticeable benefits, including the savings associated with reduced downtime and the disposal of coolant for "pumping out 20 CNC machines every 6 weeks."
Approximately 1 month after installing the first Model 315, Conval purchased a second unit in the hope that all 20 of the company's sumps will be kept free of tramp oil and floating solids.