tooling
Virtue brings its own rewards with environmentally friendly and productive ‘MQL’ drilling
The minimalist approach
THE working environment can generate health problems
related to coolant usage, and the cutting and machine tool
industry is working on the problems. One solution is dry
machining, but this can mean reduced tool life, poor surface
finish, plastic deformation of the workpiece and difficulty in
handling high temperature swarf. As an alternative, TaeguTec
has embraced the Minimum Quantity Lubrication (MQL)
process that mixes oil with air to optimise cooling .
MQL tooling delivers environmental benefits for the
customer, and better working conditions for the machine
operator, but there are also potential productivity benefits.
Conventional coolant systems may be the best solution for
general steel machining applications, but with high speed
machining processes generating temperatures of 700 to
1,000 degrees C at the cutting edge this is not necessarily so.
The coolant can evaporate at the contact area before
delivering any substantial benefit, and tool life and surface
finish suffer. A similar situation occurs with low speed
machining of heat resistant alloys such as Inconel. MQL is
also worth considering for interrupted machining: here the
application of fluid may give rise to continual changes of
temperature causing cracks - whilst dry machining causes
heat deformation and poor surface finish.
Enquiry Number: 55
84 MWP march 2008
TaeguTec has concentrated upon deep hole drilling,
particularly up to 30XD range. Prior to recent development
work, tungsten carbide and HSS drills would be used for
deep hole drilling of steel at cutting speeds from 25-60m/min
with a feed of 0.05 to 0.08mm/rev with 5-10 bar of coolant
pressure. With poor productivity and short tool life caused
by poor chip evacuation TaeguTec has developed products to
improve drilling productivity and meet the demands of
improving machine tools.
Developments with Tungsten Carbide drills and machine
tools now allow 30XD drilling at 100m/min with 50-80bar
pressure of coolant. This improves chip evacuation but
generates misting of the coolant, which causes health
problems for the employee and environmental issues for the
company. On the other hand, dry machining generates poor
chip evacuation that leads to poor drill life and performance.
The optimum solution for this increasingly common
operation is MQL drilling.
The new range of TaeguTec MQL drills have optimised
geometries for smooth chip evacuation and low cutting
forces. They reduce coolant use to almost zero whilst speeds
increase to 80 to 150m/min, feed rates to 0.15 to
0.2mm/rev. w.taegutec.co.kr
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