Kurt Manufacturing Company - Minneapolis, MN
Kurt adopted the use of a single water-based machining and grinding coolant throughout the company during 1990. This was implemented to pre-empt forth coming Environmental Protection Agency
(EPA) regulations and to capitalize on cost savings through recycling. At that time, 13 different coolants were in use. To determine the coolant to use, a committee including supervisors, engineers, and the safety manager was formed and a design of experiments undertaken using the three most commonly used coolants. Kurt was searching for a coolant that would be: safe for operators
to handle; compatible with all Kurt machining operations; repeatedly recyclable; and able to last three to four months without breaking down.
After four months of testing and collecting data, it was determined that the coolant used did not matter , what mattered was the speed and feed of the machining and tools being used. W.R Grace Coolant Daracool 706LF (a synthetic) was selected as it was the least harmful to personnel in daily operations. The changeover to Daracool was challenging but by involving operators and supervisors in the process, the job was accomplished as a team effort.
Kurt also developed a method of reclaiming and recycling the coolant. The key element of the recycling system is the Sanborn Donaldson Patriot Recycler with its 500-gallon dirty tank and 500-gallon clean tank. This system was adapted and modified to meet the company's needs. A 500-gallon standby clean tank and 500-gallon standby dirty tank were added to the recycler. Attached to the standby dirty tank is a Spenser vacuum system connected throughout the main plant with two-inch PVC piping. To recover coolant, a reclaim operator connects a hose between the sump of a machine and the vacuum system piping. Fluid is pulled into the standby dirty tank. It is recycled through the Sanborn in 500-gallon baths. As the coolant is processed, it can be directed to any machining station in the plant through a 3/4-inch return line, and discharged into a clean holding tank for storage until required. Recycled and dirty coolant is transported to and from other plants in portable Tuff Tanks manufactured by Chemical Handling Equipment, Inc. of Waldbridge, Ohio. The recycler has also been modified to automatically monitor and control bacteria and pH of the coolant.
The coolant change and recycle efforts have eliminated changing coolant every two to four weeks. Kurt has sustained enhanced machining results and has used the same coolant continuously for over one year to date. The additional prime benefit is the reduction of health hazards to employees.