There is an increasing number of machine tool companies offering products that combine additive and subtractive manufacturing on the one platform.
A ‘hybrid’ machine designed ostensibly for the manufacture of moulds is available from Sodick (
www.sodick.org).
The OPM250L is at the heart of a process for the fast manufacture of tools that are optimised for the efficient production of high-quality moulded parts. This machine, which features linear-motor drives, uses the powder-bed principle for additive manufacturing via a 500W fibre laser and a 50µm particle size.
It also features a 45,000rev/min spindle for high-speed milling, which is used to machine any required areas every 0.5mm of build height, thereby allowing the manufacture of one-piece moulds while achieving the level of high quality, shape and finish not attainable by additive manufacturing alone.
The machine is used in conjunction with ‘OPM mold’ for the optimum design of cooling channels; and compared with conventional mould manufacture, costs and lead times can be more than halved. Furthermore, the moulded product is invariably superior.
Meanwhile, Worcester-based Yamazaki Mazak UK Ltd (
www.mazakeu.com) offers its Integrex i-400AM hybrid machine. This makes use of a built-in 1kW fibre laser to melt metallic powder, which is applied layer by layer via interchangeable cladding heads.
These heads are stored in the machine’s standard 36-tool magazine and provide the ability to automatically change between additive and subtractive tooling, optimising process cycle times.
Once the additive-manufacturing process is complete, the machine’s multi-tasking capability finishes the component; and because the machine incorporates full A and C axes, it can machine and clad using full five-axis operations, further enhancing the range of geometries that can be produced.
The Integrex i-400 AM technology can be used to clad a range of material types, including stainless steel, nickel alloys and copper. This ability to cover a variety of materials makes the machine ideal for a range of applications, from repairing worn or damaged components to adding critical features or producing new parts.
The machine can be fitted with two high-performance heads: a high-speed cladding head for high-rate material deposition, delivering a bead size of 3 x 1mm; and a fine cladding head for more-intricate feature generation with a bead size of 1 x 0.5mm. Finished parts can also be laser-marked using the same head technology.
The machine retains the high level of performance of the Integrex i-series family, including 50m/min rapid-traverse rates, a 30kW 3,300rev/min main spindle and a 22kW 12,000rev/min milling spindle. It also incorporates Mazak’s latest generation of CNC — SmoothX — which has a 19in touch-screen and can be tilted and rotated to suit the operator.
Coventry-based DMG Mori UK (
www.dmgmori.com) offers its Lasertec 65 3D, a machine that has integrated additive manufacturing with lasers into a fully fledged five-axis machining centre, thus allowing the additive manufacturing of full components to precise finished-part quality — and allowing steep contours to be produced without the need for supporting structures.
Moreover, the combination of additive manufacturing with material removal on one machine allows entirely new applications and geometries to be developed, while the flexible switching between laser and milling operations allows for the direct machining of features that could not be accessed on the finished part.
The Lasertec 65 3D uses laser deposition welding for the additive process, whereby metal powder is welded to the basic material; a co-axial shielding gas protects against oxidation during the build-up process, and the metal layers can be machined conventionally after cooling.
Furthermore, compared with powder-bed additive manufacturing, powder feed is up to 10-times faster; and (depending on the laser and nozzle geometry) wall thicknesses from 0.1 to 5mm are possible. Workpieces up to 500mm in diameter, 350mm high and weighing a maximum of 600kg can be produced.