RUNNING at eight metres a minute on a complex mould, the Australian-made H&H Ultra4 machining centre from H&H Machine Tools promises to reduce costs, shorten lead times and improve product quality for mould and die makers around the world.
On recent field trials for a Melbourne tool and diemaker the Ultra4 machined an 8-tonne block of steel into a complex plastic injection mould in less than 100 hours -- one third of the job time estimate.
The machine features a unique overhead gantry design in which the CNC acts as a stationary table while the machine's axis is configured as a gantry.
The gantry itself moves overhead via columns located on each side of the table so that the workpiece remains stationary. The overhead gantry ensures the dynamic properties of the machine remain constant, allowing extremely high machine feed rates (up to 30 metres/min) with accelerations up to 0.5g.
For an end user, this means lower cutting tool temperatures, extended life, high efficiency and high volume material removal. The machine also offers substantially improved levels of surface finish.
The Ultra4 incorporates a fully controlled CNC machining 4th axis which can swivel and incline the tool while machining is in progress.
Thomas Hegmann of H&H Machine Tools says tool inclination has significant advantages. It sharply reduces the time required for actual machining via permitting higher feedrates.
Tool length is kept as short as possible while with ball nose end mills tool inclination eliminates "rubbing" so the tool is constantly maintained on the ball radius.
The Ultra4's smart control system allows the machine to run without manual supervision. The intelligent control detects tool wear and is able to select a new cutting tool (from the same family) on a fully automatic basis.
Tool length and head inclination are also measured automatically by a laser, assisting in the generation of very fast machining times, exceptional output and high level of surface finish.
The milling spindle is driven by an 18,000rpm, 21kW motor and for more demanding machining operations, such as machining ribs in hardened tool steel, the machine incorporates a sub-spindle which allows a speed of 40,000rpm using small diameter milling cutters.