RECENT technology developments in the application of ultra-high pressure coolants (HPC) are changing the way in which advanced metalworking and manufacturing industries, particularly in the USA, are operating their horizontal or vertical machining centres and turning centres, according to Dimac Tooling .
While the emphasis in machine tool technology is to reduce the machining process by a matter of seconds, HPC machining is enabling many complex metal working operation times to be reduced by a measure of minutes or hours.
The use of high pressure coolants, typically at pressures of 70 to 100 bar, using a variety of water based coolants and cutting oils, has produced numerous examples where cycle times have been reduced by up to 50 percent, tool life has increased significantly, often by a factor of twenty five times, and substantial other productivity benefits recorded.
A high pressure coolant supply, when pumped through small orifice tooling or nozzles, produces an acute, high velocity jet stream which penetrates the friction zone between cutting edge and the workplace, providing superior lubrication, cooling and chip removal.
US-based company, CoolJet Systems has been the industry leader in developing HPC technology in the form of a range of systems, including pumps, complete systems and accessories.
These include retrofit systems for machines originally designed to operate at 1.5 to 7 bar.
Dimac Tooling, a specialist in work holding and CNC machine tool accessories, has been appointed the Australian agent for CoolJet Systems, and is able to draw upon the technical expertise and shop experience gained by many advanced manufacturing centres in the USA.
Dimac general manager Paul Fowler, until recently a senior executive of CoolJet Systems, said manufacturers needed to understand at the outset, the function of coolants.
"Traditional 'flood' coolants serve to cool the cutting tool to limit heat related damage, lubricate the chip-tool interface to reduce heat from friction and flush chips away from the cutting tool.
"HPC technology using properly designed coolant nozzles and tool sealing systems, performs these functions to a degree unobtainable with flood coolant."
An additional factor, generated by the cutting speeds of today's advanced tooling can actually prevent low-pressure flood coolants from entering the cutting zone.
The majority of the cooling and lubricating effects of a flood coolant are lost by vaporisation prior to entering the cutting zone.
HPC systems generate high velocity coolant streams travelling at hundreds of kilometres an hour. This high speed stream penetrates the vapour barrier to effectively lubricate and cool the tool.
"When machine operators experience the application of HPC to a long-standing process which has always produced dark blue chips, they are usually amazed that at the same and higher speeds and feeds, silver shiny chips are produced which are cool to touch," Paul Fowler added.
Mr Fowler said there was a wealth of experience to show that conservative payback periods on an investment in a HPC system in a production environment could often be less than twelve months, based on reduced tooling consumption and improved yield.
"It is not uncommon for drastic chip control problems and tool damage situations, where the HPC investment payback can be measured in a few months or even weeks, rather than years.
"And in a smaller job shop environment, utilising high pressure coolant can often be the difference between making parts profitably and not being able to produce them at all," Paul Fowler added.
Dimac Tooling welcomes enquiries on applications of high pressure coolant systems in Australian machining and metalworking applications.