Machine tools that offer metal additive manufacturing capability all employ a laser heat source that melts metal powder, with the two functions of laser and powder delivery nearly always integrated within a unit that is toolchanged into and out of position. Variations are seen in power of the laser and the material lay-down rate/bead size, while machining centres and mill-turn machines may be the base. But there are other variations.
The most prominent metalcutting/metal additive combination machine tool development is that from DMG Mori (0247 651 6120) with its Lasertec 65 Additive that was the surprise star of the company’s Bavarian Open House event of early 2014 (see www.machinery.co.uk/59863). Fitted with a laser of maximum 2 kW, the 5-axis machining centre-based Lasertec 65 Additive’s capacity is 600 mm diameter by 400 mm height, with a maximum weight of 600 kg (YouTube http://is.gd/EdkL0P). DMG Mori says that its lay-down rate is 10-times faster than that of a powder bed additive manufacturing machine. Not new, it was not signposted heavily at EMO this year.
The Lasertec 65 Additive was not the first such development, admittedly, because at the EMO 2013 show in Hanover, Coventry-based Manufacturing Technology Centre, the UK’s Hybrid Manufacturing Technologies, Birmingham-based Delcam and German machine tool maker Hamuel Reichenbacher picked up an award for their development (www.machinery.co.uk/56485). And that was related to a UK Technology Strategy Board-backed project, RECLAIM, managed by Delcam that kicked off in 2009 (www.machinery.co.uk/17785).
But German machine tool maker Hermle (Geo Kingsbury, 023 9258 0371) boasts that “for more than 10 years now, we investigate in the development of new additive manufacturing techniques and processes” [sic]. The company didn’t have a machine at EMO, though, while it appears to employ the technology in house, offering a subcontract service to, mostly, firms operating in the mould tool making sector (more details http://is.gd/Ho3WhZ) rather than selling its hybrid machines. Hybrid-manufactured components weighing several hundred kilos and with diameters of up to 500 mm are possible, using Hermle’s C-40, 5-axis machining centre-based system.
SETTING THE PACE
But it is DMG Mori that has got into its stride first, it would appear. At the company’s EMO press conference, CEO Dr Masahiko Mori revealed that the company had installed around 20 machines – half within industry and half within academia. Of the former, no names were given. On the latter, it is process development knowledge that is a target. A comprehensive list of materials is already available, but the process knowledge data being developed will appear in DMG Mori machines in a couple of years’ time, Dr Mori said. Push-button simplicity in metal additive manufacturing on a metalcutting machine tool looms, perhaps.
Another part of the necessary ecosystem is the ability to program such machines, and DMG Mori lays claim to an exclusive development in this area, via Siemens’ NX CADCAM software. This supports full planning of additive and subtractive processes, plus NC programming to support part manufacture via the two approaches. Described as Hybrid CADCAM, this system includes a materials database and associated process parameters for additive manufacturing, automatic control of laser power, plus process parameter documentation that supports optimisation of component quality, explains first user DMG Mori.
Mazak Integrex i-400 AM
Yamazaki Mazak (01905 755755) is also a member of the additive/subtractive club, having first revealed its machine at Japan’s 2014 JIMTOF machine tool exhibition. Called Integrex i-400 AM, this is a horizontal mill-turn lathe-based system and supports 5-axis machining in either cladding or cutting operations via an NC table having both A and C axes, the latter able to pick up parts from the main spindle. The machine makes use of a built-in 1 kW fibre laser to melt metallic powder, applied layer by layer via interchangeable cladding heads stored in the machine’s standard 36-tool magazine. Interestingly, the cladding units actually hail from Hybrid Manufacturing Technologies.
The machine boasts a maximum turning diameter in its spindle of 500 mm for subtractive machining; 300 mm for additive work, plus a machining length of 1,011 mm. For the rotary table, the figures are 250 mm maximum diameter for both processes and a maximum workpiece height of 160 mm.
The exhibited machine had two new cladding heads, a high speed unit for high rate material deposition delivering a bead size of 3 by 1 mm, and a fine cladding head for more intricate feature generation that creates a bead size of 1 by 0.5 mm – “providing robust process flexibility to meet a range of application requirements”, says the company. This two-head approach appears to be a Mazak differentiator.
Machine programming can be undertaken via Mazak’s SmoothX CNC unit (see also p25), although complex parts require offline CAM programming, but only toolpaths are created for additive operation; extra information is added via SmoothX.
Yamazaki Mazak’s Alan Mucklow, European group product manager, says: “Given the potential of additive manufacturing to not only drastically reduce material wastage compared to other manufacturing methods but also in its ability to combine a variety of different metals and alloys, we believe the Integrex i-400 AM to be the start of a hybrid machining revolution.”
LARGE-SCALE EFFORT
Staying with mill-turn technology but moving up the scale a bit and Austria’s WFL (Kyal Machine Tools, 01780 765965) can fit much higher power lasers to its machines, as Machinery revealed earlier this year (www.machinery.co.uk/75353). At the EMO event, the technology’s first major public outing, a 1 m turning diameter M80 Millturn machine with 4,500 mm centre distance was on show, but as well as offering the 10 kW source that Machinery saw, the option of a 40 kW Laserline diode unit was highlighted at EMO. The WFL machine is not only for additive manufacturing or cladding, but also supports hardening and laser welding, for example.
Explains Reinhard Koll, applications engineering manager at WFL: “In spite of the enormous range of processes provided by the Millturn machines, in the past it was essential to unclamp the workpiece in order to carry out further machining in another area, and, if necessary, to then return it to the Millturn for finishing. This is generally necessary during processing operations that require curing, something to be welded on or material cladding.” He examples parts requiring the application of wear-resistant coatings on gear teeth that are manufactured using a WFL Millturn and which then require subsequent ‘curing’.
Programming is via a CAM system plus WFL-specific cycles (WFL uses TopSolid but other CAM systems can be used). Its own software, Millturn PRO, part of its online simulation program CrashGuard Studio, supports both on- and off-machine programming.
Other members of this growing metalcutting/metal additive club that attended EMO include Japan’s Sodick and Matsuura, Spain’s Ibarmia and America’s Hurco, all with machining centre-based technology.
The Sodick development sees a powder bed/laser approach plus separate milling spindle
First launched at Japan’s 2014 JIMTOF, Sodick’s OPM250E (Sodi-Tech, 024 7651 1677) has been developed to provide particular benefits in the design and manufacture of plastic injection mould tools, combining 3D printing to produce conformal cooling channels with a 45,000 rpm spindle to support the cutting of high quality finishes. This machine is different to all the others so far mentioned in that it combines powder bed laser sintering with metalcutting. That means that there is a dedicated mirror-positioned laser beam for melting powder and a separate machining spindle for cutting. For the OPM250E, a part is built up layer-by-layer with machining interspersed with that.
The machine has a working envelope of 250 mm3, so is aimed at small parts – mobile telephone cases is an example instanced. It has a 500 W laser source and the LN2RP CNC unit “offers the one stop manufacturing method for dies and moulds, from CAD design to NC program”. An external CAM system from OPM Laboratory Co (http://opmlabenglish.net), Marks-Mills, is available, with various modules to support laser sintering, machining optimisation and simulation. OPM Laboratory Co is a CAM specialist in this additive manufacturing area, particularly as regards mould tools and conformal cooling.
Matsuura’s offering (01530 511400), the Lumex Avance-25 metal laser sintering hybrid milling machine unveiled in 2011, is, like Sodick’s example, a combination of powder bed and separate milling spindle.
It has been sold into the die and mould industry in Japan and Asia, reports said last year, so there wasn’t much fuss around this machine on Matsuura’s stand at EMO because, once again, it isn’t new. The machine “performs the sintering of complicated mould dies without splitting them, thus eliminating assembly and adjustment stages and making it possible to produce mould dies with no dimensional errors”, says Matsuura (see YouTube http://is.gd/eEkdAE). The machine went on sale in North America in January 2014.
Ibarmia’s effort, unveiled first at this EMO, operates at the larger end of the scale, with the company saying it can fit a 3 kW laser source and powder supply system to its Multiprocess machining centres. Large machines having X-axis strokes of from 1,600 to 12,000 mm are offered by Ibarmia, which, the company says, means that it offers “one of the biggest working areas in the market for hybrid machines”. (The laser source/powder supply head is manufactured by Germany’s Precitec (www.precitec.de/en).
Ibarmia has added this capability first to its moving-column machining centres with fixed table range, ZVH, with the result being its ZVH Add+Process model. As part of its development, Ibarmia (Dynamic Machine Tools, 01642 479295) has worked on optimising the cladding process, as it calls it, with various models generated to optimise process parameters and define properties of the layered material. Process control and monitoring have additionally been developed.
Programmed by using a CAM system without any additive awareness in toolpath terms (although says Siemens NX is coming), the machine CNC is where additive process knowledge resides. Says the company: “We ‘trick’ the program by starting from the ‘final geometry’, generating a program to remove all the material and then inverting the axes.”
Hurco (01494 442222) was another company displaying additive manufacturing, intended for use on its machining centres, but this was very low-key stuff. A mock-up of a head was shown but little detail available. A key difference between Hurco’s effort and others is that it is plastic additive manufacturing that is the focus, with a plastic wire filament feeding into a head that is manually mounted to and removed from the spindle unit. The head features on-device control that modifies temperature and feed rate, with the rotation of the spindle generating heat, in fact.
Now, apart from these combination machines, there are moves by other well-known machine tool companies to climb onto the additive manufacturing bandwagon, but through different means.
In the case of GF Machining Solutions (024 7653 8666), an EDM and high speed and 5-axis machining specialist, this is via a partnership with additive manufacturing expert EOS (01926 623107). At EMO, GF Machining Solutions introduced its AgieCharmilles AM S 290 Tooling, based on the EOS M 290 powder bed machine. Once again, it is mould tools and conformal cooling that are the targets here, but a complete production system is the aim.
“GF and EOS will undertake the integration of the additive manufacturing machines into the production process of mould inserts, including the necessary software and automation link with downstream machine tools and measuring devices,” says GF Machine Solutions. This automation was not a clear part of the EMO display, however; future developments are, therefore, awaited.
GRINDING COMPANY INITIATIVE
Finally, United Grinding (which comprises Blohm, Ewag, Jung, Maegerle, Mikrose, Studer, Schaudt and Walter) has this year established a joint venture with the university-affiliated Inspire AG, called IRPD AG and headquartered in St Gallen, Switzerland. “IRPD specialises in additive manufacturing processes such as laser-based processes and 3D printing. The focus of the joint venture is to further develop these cutting-edge production processes and thereby benefit from current research findings.
ETH Zurich has made significant investments in Inspire AG,” says the company, and CEO United Grinding Group AG Stephan Nell adds: “Additive manufacturing processes are of high strategic relevance for us.”
As to whether this additive manufacturing capability will make it into the group’s grinding machines, Fred Gaegauf, CTO United Grinding Group, would not be drawn at the group’s EMO press conference. German creep-feed grinding specialist Elb (not at the show) has already done this,for example.
Quite clearly, additive manufacturing developments both new and recent by metalcutting machine tool makers are beginning to add up to a strong trend.
This article was originally published in the November issue of Machinery magazine.
