Focus on Additive Manufacturing

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An interview with Mr Andrzej Grzesiak, who heads the Fraunhofer Additive Manufacturing Alliance, in the run-up to EMO Hannover 2011 to be held from September 19 to 24

Focus-on-Additive-Manufacturing-1.jpgIf you are building a house, you're hardly going to mill rooms, doors and windows out of a huge block of stone. When it comes to machine housings made of metal, however, this is the norm - for the time being. Although the EMO Hannover 2011, as one of the world's premier platforms for innovation, under its motto of 'More Than Machine Tools', will be opening up the shop window of additive manufacturing just a little, this technology is hardly going to leave foresightful machine tool manufacturers cold. Freelance journalist Walter Frick talked about this to Mr Andrzej Grzesiak, who heads the Fraunhofer Additive Manufacturing Alliance at the Stuttgart-based Fraunhofer Institute for Production Technology and Automation (IPA). Excerpts:

What advantages do additive manufacturing have in regard to producing complex geometries?

The salient advantage of layer-forming processes is that any conceivable shape that can be created in a 3D CAD programme can actually be produced. There are no restrictions in terms of manufacturing transparent or hollow structures. Nor are there any problems with complex geometries and free-form designs.

Focus-on-Additive-Manufacturing-2.jpgAdditive manufacturing was at first reserved for making models and prototypes - where are the practical applications in terms of series production?

We are only at the very beginning of developments. New, improved materials and more stable processes are being developed. Nonetheless, we are already seeing the first best-case applications with implants, dental technology and light automation components. Individualised mass production is up and running almost everywhere in these fields. We are also seeing new applications in aircraft manufacture, where metal-based lightweight construction using titanium is set to play a particularly large role.

Are there any limits to creative design freedom? Will traditional design guidelines be rendered obsolete?

Direct, fast manufacturing by means of additive processes, thanks to its well-nigh limitless freedom in terms of shape and design, enables customised, optimum products to be created. By virtue of the geometric freedom provided, and the high elasticity of the material involved, moreover, it is possible to manufacture snap-fit connections, complicated form-locking elements, spring-force connections and geometries like leaf springs or helical springs. This means fewer parts have to be mounted or connected with tools. This is something design engineers first have to learn.

Focus-on-Additive-Manufacturing-3.jpgWhere do you see the main application categories for additive manufacturing - medical technology, mechanical engineering, tool and die construction, aerospace?

All these fields are of interest. We draw distinctions here not by sectors, but by applications. In all of them, individualised mass production for specialised parts and components can be achieved at affordable prices.

Are there any differences in the user target groups - between micro-systems engineering and forging-die production, for example?

Yes, simply because quite different requirements are posed for the engineering and the materials involved. Quite different technologies will be used here too. It's important not to introduce additive manufacturing techniques everywhere, but first to comprehend what the customers actually need. This will enable additional markets like biotechnology to be successfully penetrated as well.

Focus-on-Additive-Manufacturing-4.jpgWhich of the various methods for additive manufacturing has the best prospects for broadly based industrial adoption in the long term?

You shouldn't compare the various technologies directly. Depending on the particular application being planned, you have to choose the appropriate technology. This is also important for newcomers: first the application, then the technology. Nowadays, laser systems are being used especially in the field of end-part production.

In future, printing technology systems will be used more and more, particularly in micro-systems engineering and biotechnology. There's going to be a lot happening here in the next three to five years.

What role does additive manufacturing play nowadays in automated process chains?

None as yet. Although the integration of new manufacturing methods into industrial process chains offers far-reaching options for optimising production operations, due to the lack of organisation and the stand-alone machines the implementation status is as yet not very far advanced. By reason of minimal batch sizes and the elimination of assembly processes thanks to complete manufacture, there is concomitant potential for streamlining, though this, of course, has to be supported by the correct organisation.

Additive manufacturing enables certain problems to be solved in conventional production structures, though the integration of these systems in the triangular matrix of time/costs/quality is being rendered rather difficult by the current lack of comprehensive production models.

How about the reproducibility of the processes involved, about quality assurance in mass production? Are there any dependable methods of simulation?

The reproducibility of the processes involved is a principal focus of ongoing development work, and will have to be achieved over the next few years.

The subject of quality is dealt with in VDI Guideline 3405, entitled 'Additive Manufacturing Processes'. There are numerous research projects running at the moment, as well as in-house development work at the equipment producers, who then address the issue.

Can additive manufacturing entirely replace conventional processes?

No, nor should this be the goal of development work. The right approach is to define the correct application categories and to replace existing conventional technologies only where commercial and technical advantages are to be gained. The technologies should co-exist and complement each other to optimum effect.

So there's no risk that additive manufacturing will, in the long term, put conventional machine tools out of work?

You should never say never, but I don't think so. Both technologies simply have their own advantages that can be selectively utilised.

There are, however, certain fields, such as dental prosthetics, in which the machine tool will, in my estimation, be replaced over the next few years.

Against this background, what do you expect from the upcoming EMO Hannover 2011?

The major machine tool producers are showing progressively more interest in additive manufacturing. In the final analysis, every machine that processes and produces work pieces is a manufacturing machine.

Whether this is to be done with a laser or a milling head will in future be a matter of choice. Perhaps the first developments will already be on show at the EMO Hannover 2011. I am confident that if it doesn't happen this year, it definitely will soon afterwards.

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