Departments - Technical Tips
Quick Chip Disposal and Clean Coolant
1/8/2010
Coolant has long been a critical element in machining operations.
An Ohio contract manufacturer turned to Maytran International's MagSep Conveyor for a dedicated cast iron application on its a61 Makino HMC.Coolant has long been a critical element in machining operations. The increased speeds and higher metal removal rates of today’s newer machines create more chips, placing increased demands on the coolant and on associated chip-removal and coolant filtration equipment. Many machining operations have moved to high-pressure coolant systems for faster chip removal and greater precision – magnifying the adverse effects of chips or other contaminants.
An Ohio contract manufacturer that produces parts for the energy and solar power industries on a 5-axis Makino a61 horizontal machining center recently discovered this issue. That is because in addition to chips, cast iron machining creates fine particles, in the range of 25µm, which quickly suspend in the coolant to create sludge. Therefore, with today’s high-performance CNC lathes and machining centers with high cutting speeds, this can produce many cast iron fines in a short time period.
For example, a 30hp machining center can produce up to 25ft3 of chips and 150in3 of sludge in a 24 hour time period. Chips and sludge on typical machine installations can migrate through to the “clean side” of the coolant system resulting in increased wear, which necessitates more frequent and costly maintenance causing lost production time.
The problem of chips and fines migrating back into the machining process is a critical element in the performance equation. Consider the blockage of coolant distribution channels, including the system’s pump, reducing coolant flow to tools and parts. This can result in chips not properly flushing from parts and workholding, premature tool wear, inaccurate tool compensations, and higher heat that can work harden areas of the part. Eventually, the pumps will cavitate, potentially burning out motors or wearing seals. In addition, when chips and fines accumulate in the reservoir – to the point where their volume displaces too much of the fluid – the coolant temperatures begin to rise, resulting in evaporation and further quality issues.
For a solution, they turned to Mayfran International, who supplied a MagSep Conveyor for the dedicated cast iron application. With the MagSep magnetic drag (or scraper) conveyor, coolant and chips are directed to the magnetic surface before exiting the conveyor. The magnetic bottom pan attracts ferrous chips and fines and the conveyor flights continually remove chips from the bottom pan while clean coolant exits the tank.
This results in coolant clean enough for many machining operations but for this application Mayfran upped the ante with the addition of an AT-Cleaner Coolant Cleaning system. The AT-Cleaner, a media-free unit, further cleans the coolant, removing fines and maintaining a 10 to 15 nominal micron level in the coolant. In addition, the AT-Cleaner is maintenance-free, requiring no media filters to change and dispose of, resulting in lower costs and more spindle uptime.
Benefits of the Mayfran MagSep/AT-Cleaner approach quickly became obvious: The company eliminated eight days of downtime totaling 320 labor hours, and eliminated $8,000 in drum screen replacement costs every three months. Understandably pleased with these results, and the rapid payback they saw, they plan to add a Mayfran MagSep with AT-Cleaner to their next machine.
In an unforgiving competitive environment, machining facilities are constantly striving to optimize all aspects of their operation. Time and energy are expended on questions of machine tool design, control technology, material handling, and process improvement strategies. Rarely do questions of chip disposal and coolant management receive the same degree of attention. They should. Chip and coolant management impact cost, quality and productivity – in other words, they impact survival.
Mayfran International
Cleveland, OH
mayfran.com