One way to avoid problems during drilling, particularly deep hole drilling, is to look at your coolant delivery system.
Three types of coolant systems are common: flood coolant, low-pressure through-spindle coolant and high-pressure through-spindle coolant.
With flood coolant, less and less coolant reaches the tool tip the deeper the drill penetrates the workpiece.
Eventually, no coolant can get to the bottom, and machining occurs dry. As a result, chips become impacted in the flutes of the tool even though coolant is visibly flowing over the top of the hole.
In fact, the hole ends up being dry cut, while the tool heats up and is subjected to premature wear or breakage.
However, retrofitting a machine for high-pressure coolant supply can be a costly exercise and for many operations the extremely high-pressure of 70bar is not always necessary.
Medium-pressure coolant systems can be a good alternative, because they still have a positive effect on both chip breaking and heat.
Dimac Tooling has released new Cooljet Medium-Pressure units, which overcomes this issue. The coolant forced into the cutting zone at a medium pressure is more effective in removing heat than at low pressure and increases tool life and allows the use of higher cutting data.
The new Cooljet Medium-Pressure Unit features a fixed coolant flow of 30l/min (8gpm) at 20bar (300psi), a single high-capacity filter and a 150 litre (40 gallon) tank. The unit allows for a quick and affordable installation, without the need to modify the machine tool.
A Plug&Pump interface developed by Cooljet allows rapid and intelligent connection. On top of this, the machine is compact and only occupies a space of .5 metres by 1 metres.