Core Injection vs. 3D Core Printing

September 26, 2016

Innovation accelerator in engine construction Mahle König focuses on 3D-printed sand cores from ExOne

Mahle König, a company based in Rankweil, Austria, ranks among the world's leading manufacturers of components for high-performance engines in the fields of leisure, motorcycling, as well as industrial and heavy-duty applications. Their strong market position rests primarily on innovative methods such as 3D printing technology from ExOne, a Gersthofen-based company. Even more so, Mahle König applies this future technology for mass production of small to medium lot sizes. Its potential, however, is far from exhausted, as the technical director Dr. Georg Geier explains in an interview.

Mahle König introduced 3D printing processes very early in the series production of engines and components. Does your company consider itself a pioneer of sorts in this area?

It is certainly fair to say so. In fact, the use of modern production methods has always been part of our corporate philosophy. Since its founding by Carl König, Mahle König has regarded itself as a technology driver and innovator. Nowadays, we are pioneers in our field, not least because of the close development partnership with our customers.

What benefits may your company derive from these partnerships?

For two and four-stroke engines, as well as diesel and gas gensets, partnerships favor the construction of numerous products with exceptional performance, efficient consumption, and low emissions. In turn, this relies on the development and production of cylinders, cylinder heads, pistons and piston rings from a single source.

And how about the expertise of the company and its employees?

That's no doubt a key factor too. Furthermore, Mahle König provides an optimal development environment. In this respect, we regard the latest technologies suitable for mass production as an essential building block to develop and build innovative engines. Needless to say, 3D printing counts among such technologies.

Are these technologies also a way to meet challenges generally faced by the engine construction market - and by Mahle König in particular?

Absolutely. In the future, global markets will be influenced by two diametrically opposing paradigms. On the one hand, customers are demanding customized products for their target groups, that is, products that combine high performance, quality and reliability - and this partly in the most adverse environment of high temperature, abundant humidity, or dust. On the other hand, customers expect very cost-effective, resource-saving, and ever-lighter engines.

In this situation, what opportunities arise for suppliers?

Clearly: Growth - that is essential. Today manufacturers primarily seek extremely adaptable suppliers, which lower lead times for larger numbers of new product options, and do so without compromising on quality. At issue here are small and very small series with increasingly complex and sophisticated geometries, for which production technologies constitute a decisive success factor.

And what role does 3D printing play there?

Powerful 3D printing is one of the key technologies to retain production in high-wage countries. For us, 3D printing of sand cores is also an opportunity to increase our technological lead in engine construction, as well as to further secure a unique market position for our Austria's production site through new competences. Our strengths, therefore, lie in superior engineering, and the use of intelligent technologies. Accordingly, we endeavor to expand long-term benefits in the intelligent, highly flexible manufacturing lines, differentiating ourselves from international competition in doing so. This we accomplish through the networked digitizing of the entire production chain: In prototyping and product development, but also as regards the flexibility, quality, and efficiency of mass production.

Can you briefly describe the advantages of 3D printing of sand cores over traditional production processes?

With pleasure. Compared to the classic production, 3D printing offers enormous potential for innovation, both in development and optimization, as well as regarding serial production flexibility. While we cannot yet estimate the total potential of this technology for a global, networked digital production, we already see concrete examples of the enormous impact of 3D printing on all industries and areas. In construction, for example, 3D printing affects process and product quality, as well as flexibility and production optimization.

Benefits of 3D printing over core injection

> CAD design: De-composing of complex internal geometries can be omitted, mold parting design, draft angles and core locks omitted, pressure strips no longer required

> CAM-tool manufacturing: Core boxes and models no longer required, assembly jigs unnecessary

> Initial sample: Function test / zeroing eliminated, necessary adjustments (ventilation etc.) eliminated, binder-dependence eliminates core drying and finishing, deburring unnecessary, tool changes based on measurement results unnecessary

> Cost: Lower investment and change costs, no tool maintenance and storage costs, no tool insurance cost

> Time: Shorter change periods and development times, several tests possible in one step

> Process safety: Reduction of individual components, elimination of manual activities (assemblies), lower testing costs

> Productivity: No tool wear, no risk of tool loss, high user friendliness, without affecting the series, uncomplicated transfer of production from one to another foundry, simple binder changeover

Could you provide some concrete examples?

We find a good example in the increasingly complex geometries required to build high-performance, ever lighter, and more fuel-efficient engines. And improving these demands a corresponding reduction in manufacturing tolerances. It is precisely here that conventional production methods are reaching their limits. On the other hand, digital sand core printing allows representing such complex geometries in a single core instead of a multipart core package. That means that drafts become unnecessary, loose parts need not be considered, and undercuts are possible. Not to mention that the finishing process for aluminum die casting can be omitted if cores are produced digitally. Expressed otherwise: there can be no errors in a non-existent process.

So, is 3D printing equally profitable for all batch sizes?

Not yet. At present, 3D sand printing is particularly interesting for series of small to medium batch sizes. We're nonetheless still skeptical when it comes to mass production. As I said, not yet! We expect that the process will soon grow its potential by increasing print speed and a growing capacity to produce variants and modifications - also those developed in series. In the future, therefore, the process will become a smart alternative to conventional techniques even for larger series - possibly also in hybrid mode. Accordingly, we see our current entry into 3D sand printing technology as an investment in the future, because we can adapt processes to the required dynamics of the digital industry today.

Could you provide further examples of the future potential of this technology?

For example, 3D printing has huge future potential for research and development. This technology allows geometries that were impossible with conventional processes up to that point. In turn, this paves way for the construction of hitherto unthinkable engines. What is more, the "one-piece core" offers an ever more precise reproduction by eliminating the manual core assembly. This clearly increases process reliability, while reducing testing costs and production scrap in a consistent manner.

Does that affect development and delivery times?

Absolutely. Today, Mahle König is capable of notably reducing delivery and development times by reducing or eliminating costs and time-consuming tool processes. Under these conditions, series-parallel developments become much more interesting. Of course, the same applies to the flexible shaping of variants, small series or special versions - for example racing variants of standard motors. Changes are incorporated in almost real time in production, given that they are passed directly as CAD (without tools) information. There is no risk of damage due to production errors and tool wear in this digital production environment.

What about the environmental impact of the technology? Is this something your company considers?

Of course. Currently, we 3D print with an environmentally friendly binder system based on silicates. Thus, we combine the innovative possibilities of digital core production, with a resource-saving and especially low-emission production. Lower odor emissions are a major advantage over organic binder systems. For us, this represents a further and major step towards an efficient and sustainable production in Austria. What other reasons made you choose a silicate binder from ExOne? With ExOne, the first and, as far as we know, only supplier to offer a market-ready solution for the production and processing of inorganic cores based on silicate in 3D printing, we can quickly and easily leverage the technical advantages of this process for our production. For example, to avoid gas-related defects in the cast component and prevent condensation build-up in the mold, which substantially reduces cleaning costs. For a die casting manufacturer like ourselves, there are convincing arguments to support this technology.

You collaborate with ExOne on 3D printing. What was the key factor underlying this decision?

First and foremost, the good teamwork. In our view, only close partnership can deliver strong results. All customers, in fact, can and should expect such cooperation from us. And we expect the same from our service providers. With ExOne, we found the right partner.

Are there any other reasons?

In our opinion, ExOne has the most compelling technology package for 3D sand printing. Moreover, the company won us over from the first day with its deep understanding of our tasks and products. And there is just another crucial factor. We seek to make every process step as environmentally friendly and emission-free as possible, especially in such a resource-intensive process as casting. ExOne supports us in that respect. ExOne is the first and, as far as we know, only supplier offering a marketable solution for the production and processing of sand cores in the program, where a modern, environmentally neutral binder is used. Last but not least, digital 3D printing with ExOne technology allows emission reductions during core drying and casting.

Thank you for speaking with us.

www.exone.com

www.koenig-kg.at