"The OHLF Opens Up Completely New Areas of Research"

The Open Hybrid LabFactory brings together experts from research and industry: an interview with Professor Dr. Klaus Dilger (OHLF) and Thomas Papenheim (IAV)

Lightweight design is a key issue for conventionally powered vehicles and for electric cars. Autonomous driving also makes new demands of the vehicle structures. The Open Hybrid LabFactory (OHLF) in Wolfsburg brings research and industry together under one roof to develop new solutions and make them ready for volume production. In the automotion interview, Professor Klaus Dilger (Chairman of the Open Hybrid LabFactory) and Thomas Papenheim (IAV Executive Vice President for Vehicle Safety and Vehicle Exteriors) talk about the special aspects and prospects for the ambitious project.

Professor Dilger, what are the aims of the Open Hybrid LabFactory?

Dilger: Our aim is to ”democratize“ lightweight design. We want to develop and produce lightweight structures at low costs in terms of material and production. Here it is important to understand the important role played by both the material and the actual production process. While one kilogram of steel costs about one euro, aluminum already costs three to four euro per kilogram, compared to around 20 euro per kilogram for CFRP. Then there's the time it takes to make CFRP parts: processing costs make up about half of the part costs. So we want to move away from monocoque structures made from one single material towards an intelligent material mix that lets us make lightweight structures at competitive costs.

Why has this idea not yet been introduced in volume production?

Dilger: We already have a multi-material mix on the vehicle body level. But here already we encounter complex problems with the joining processes. For example, we can't weld steel to aluminum: instead, the two materials have to be joined mechanically or with an adhesive, resulting in various technical challenges in the production process which can also impact on the properties of the vehicle. It is worth giving a special mention to the differing thermal expansion coefficients of the materials, resulting in adjustments to the process chain and the joining processes. Integrating different materials on the vehicle level is by no means a trivial issue. But the OHLF takes things even further: we want to achieve the multi-material mix on the part level, and in just one step where possible. Our motto: one cycle, one part! The aim is for the production methods to compensate for the higher material costs.

What is IAV's contribution?

Papenheim: We want to play an active role in shaping lightweight design and have already completed a number of projects in recent years, including funded projects. Meanwhile we have become the partner of choice for several OEMs when it comes to lightweight design. But in my view, the OHLF is aiming for a quantum leap. I’m sure that the multi-material mix will become indispensable in future, and we can actively influence this development. This is why we have decided to be full members of the OHLF, with our involvement in the Advisory Board giving us a say in the projects and investments. Our involvement also lets us establish IAV as a leading lightweight design company. This is particularly important in my opinion, because reducing weight will play a central role in the years to come – to achieve the CO2 targets in vehicles with combustion engine and to increase the traveling range of electric vehicles. In future, developments in au
tonomous driving will also result in new vehicle concepts and more extensive uses for lightweight design.

Dilger: Here we're mainly talking about changed vehicle structures. They need to be not just lighter but completely different from what we know today. Electromobility, for example, demands a different concept for the vehicle structure than a vehicle with combustion engine in view of the completely different distribution of mass and attachment points. The same also applies to autonomous driving. Furthermore, in future there will also be more vehicle variants to cope with. In other words, we want to be in a position to produce vehicle structures in a completely new way, for example also in small quantities at low prices.

Papenheim:  I also expect the development process itself to change in the next few years. For example, there will have to be a lot more virtual development and we will need completely new tools. Although this is not specifically a lightweight design issue, it will still have a great impact on this area. IAV is working on such new virtual development methods that we can also contribute to the work of the OHLF. On the other hand, by working together with our other partners we are also learning a lot about what is actually possible in the field of manufacturing.

How much funding has been provided and how long will it last?

Dilger: The federal government is providing us with 30 million euro for projects over a 15-year period, on condition that we create our own infrastructure. So we had to raise a further 60 million euro for the building itself and all the machinery and equipment: here we have received very welcome support from the city of Wolfsburg, the federal state of Lower Saxony and our industrial partners.

Papenheim: IAV also has a financial stake in various OHLF projects over the next few years. One of these is MultiMak2. We are working with partners to create the basic principles for taking key parameters such as weight, stiffness and other material properties to calculate how a material mix will behave or what its life cycle assessment is like. In this context we are setting up a database to help ascertain whether a certain concept is appropriate – not just in terms of lightweight design but also looking at costs or production feasibility.

How many projects are underway?

Dilger: At present we are working on about 80 projects, and have already started planning the second application phase after 2018. Key aspects will include understanding materials and simulation, things that we can work on very well in cooperation with IAV. Among others, we will be looking at the previously mentioned problem of different thermal expansion coefficients and their impact on the production process. We use CT scans to look inside the material and produce new material models. Another focal issue is in understanding the metal/plastic contact surfaces: what do these interfaces have to be like to create a lasting bond between the two materials? This entails characterizing and modifying the contact layers. All this is absolutely fundamental research and in some cases, globally unique.

When do you expect the first results to be used in volume production?

Papenheim: Well it won't happen overnight. But I think we will be able to use the first results in customer projects sometime in the next three years.

Dilger: Other projects have already triggered start-up businesses which in turn also work on funded projects. The OHLF has already produced tangible results that are now going through further development elsewhere.

What does the new building offer in terms of special equipment?

Dilger: On the one hand, we can cover the whole process chain – from textile production through to the finished part. In future we even want to produce our own carbon fibers. On the other hand, we can make everything ourselves, from samples and prototypes through to actual vehicle structures. We've got all the machinery we need here in the building, including injection molding presses and hybrid forming presses. Then there's our large CT scanner, our climate chambers and a special scanning electron microscope for characterizing plastic surfaces.

Is the Open Hybrid LabFactory still looking for more members?

Dilger: Currently almost all positions along the supply chain have been taken, so that we are first aiming to consolidate. But as part of our internationalization strategy, we will be looking to establish networks with other major research facilities worldwide.

Professor Dilger, does the OHLF fulfill your scientific dream?

Dilger: It is certainly an incredible project, already in terms of the sums of money that are involved and this fantastic building. Then it's also great to work at such close quarters with industrial partners, putting our cooperation onto a new level of quality. This naturally gives us valuable impetus in our teaching activities and for our young scientists. The OHLF is definitely something very special and opens the door to completely new fields of research. I've been involved in research for 30 years now and have never experienced this kind of cooperation in any other project.

Many thanks for the interview.