In machining operations, tools are exposed
to severe conditions of mechanical loading, wear and temperature,
and many operations, such as milling, involve the intermittent engagement
of the tools. Under these conditions, cracks can easily propagate,
causing chipping and ultimately tool failure.
This project's objective was to develop
computational design aids for new generation milling tools based
on coated hard metals with gradient structures. These computational
aids allow a tool designer to test different combinations of coatings
and substrates to optimise load carrying and crack resistance for
the particular application. The transition from non-coated hard
metal milling grades to optimised coated grades with gradient structures
will effectively increase tool life, possibly by 50 %, with consequent
benefits in machining efficiency and costs.
The new tool set will allow tool designers
to move away from trial and error and will greatly improve machining
efficiency, say partners, and with the world-wide cost of milling
estimated at 50,000 MECU, 25 % of which is incurred in Europe, only
a small percentage improvement would have a large economic impact.