Automotive Diecasting Supplier Uses Tomograph to Ensure Quality and Process Stability

Management at the TCG UNITECH Group (TCG), an Austrian high-pressure die casting and injection molding company, has achieved what many executives only dream of – outperforming the competition in their industry.

The company went from being just one of many die casting companies to an industry leader in just a few years. To remain competitive, the Managing Directors at the headquarters in Kirchdorf, Austria decided to add a ZEISS computer tomograph to their existing system fleet comprising 16 ZEISS coordinate measuring machines and two ZEISS microscopes. “Inspecting cast blanks with a computer tomograph is still the exception rather than the rule in our industry,” says David Demmelmair, Head of Quality Management at TCG, as he walks through the foundry. The Austrian automotive parts supplier has 1,100 employees, including a joint venture in Dalian, China, and the decision to invest in this innovative technology two years ago reflects the foresight of its two Managing Directors. They see computed tomography as a tremendous opportunity, as Managing Director Walter Mayer explains: “This allowed us to further optimize our own processes and become the casting house that sets the pace.” Peter Wienerroither, the other Managing Director of the TCG, could not agree more: “Automotive manufacturers and their tier 1 suppliers continue to increase their requirements concerning quality, price and sustainability. This requires us to use cutting-edge technology if we want to stand out from our competitors.”

A Bright Future

The two Managing Directors have headed the company since 2012 and are the reason the newspaper OÖNachrichten declared this “one of the most impressive economic success stories of the past several years” at the end of 2017. This achievement was particularly surprising because, in the wake of the economic crisis in 2009, the company – the largest employer in the Kremstal area – was on the verge of collapse. Today, TCG employs 70% more employees than in 2010, and the company generated twice as much revenue in fiscal year 2017 versus this earlier period – the result of bold investment decisions. Since 2010, the company has spent more than 200 million euros expanding and modernizing its machinery. For example: while TCG used to have fewer than 20 die casting machines in 2010, today there are 31. “And that will not even be enough for us to hold our own in light of the automotive market‘s forecast growth,” explains Mayer. Currently, the company is investing 90 million euros in a new, 48,000 m² die casting facility. The first machines are scheduled to be up and running in January 2019. Located near company headquarters, the components produced at this production facility will include an electric power train. “We want to grow by offering all types of drive trains,” says Wienerroither, explaining his company‘s decision. In 2017, the TCG revenue totaled 220 million euros. “For us, this is just a milestone. We are aiming for 250 million euros,” says Mayer. “We see ourselves as the automotive industry‘s partner, and our company is growing by continuing to drive innovation and offering highly complex products.” In addition to developing and manufacturing oil and coolant pumps, the Group also supplies diverse plastic components to companies like Audi, BMW, Daimler, Bosch and VW. TCG focuses most sharply on its approximately 320 different aluminum and magnesium high-pressure cast parts. These include steering gear housings, camshaft carriers, cover plates and thin-walled interior parts which the Austrian company also processes with highly precise, CNC machines so that they are ready to install. In order to optimize their overall die casting processes, they began using a ZEISS METROTOM-1500 over one year ago.

CT scanner for reliable results

More than two years ago, Rene Klaffenböck, Head of the Lab team and Environmental Officer at TCG, explained to company management why the investment in a computer tomograph or CT scanner would pay off for the casting company. The engineer‘s calculations won out, and a ZEISS METROTOM 1500 has been in use right next to the production line at the Kirchdorf site since 2016. What is the greatest benefit of the system according to Demmelmair and Klaffenböck? “We can now determine whether the porosities detected are air pockets or shrinkage very quickly and, most importantly, reliably. This insight enables our die casting team to make the right adjustments to the machines,“ says Klaffenböck. Thanks to the ZEISS METROTOM 1500, TCG can now combine potential changes to the component directly with die casting process parameters and take targeted countermeasures if there are errors. The initial results have confirmed that the engineer‘s calculations were correct, even though Klaffenböck is still waiting on the exact figures for the reduction in scrap because the machine has only been in use a short while. Process optimization is not the only advantage of this CT scanner: now quality managers no longer have to perform additional measurements with other machines. “Instead of four quality-assurance inspections, we just measure once on the ZEISS METROTOM,“ reports Klaffenböck. It used to be the case that the die casting employees first needed to inspect a component like a steering column with an X-ray system to identify and analyze potential cavities. If anything appeared defective, then the parts were taken to the lab. The particular locations on the components were ground down and then analyzed under a microscope, a process that took several hours under the best conditions. Meanwhile, other potentially defective parts were still being produced. Thanks to the CT scanner, there is no longer any need to inspect die cast parts on a CMM, and no employee has to walk all the way across the factory premises to the measuring lab to deliver the parts. Klaffenböck knows that this is all a real time saver. Moreover, an external service provider used to measure the die cast parts with a fringe-light projector. Introducing cutting-edge technology has eliminated this step and made the overall process even quicker. Klaffenböck has nothing but praise for the new system: “Without the CT scanner, we would have had to invest in additional measuring systems and operators. And in spite of all that, we would still need more than an hour to determine the type of defect and how best to respond.“ And that is not all: with new orders, another advantage of the CT scanner has come into play. “For new parts or sampling, we now receive a complete, detailed image, and tool correction is fast and efficient with ZEISS Reverse Engineering software,” says Demmelmair. Moreover, customers have corroborated the promising initial results at TCG. “This has sped up approval for batch production,” says Demmelmair. Finally, Demmelmair and Klaffenböck expect that computed tomography will save automotive suppliers both time and money. However, the introduction of the CT scanner has hardly made the company‘s coordinate measuring machines (CMMs) superfluous. “They are still an indispensable part of the quality assurance process for machined, ready-to-install parts,” says Demmelmair.

 Ahead Of The Competition

“A CT scanner is an innovative technology,” explains Klaffenböck. “Thus it was and is challenging to develop measurement strategies that ensure our CT results are comparable to those we would get with our other measuring systems and methods.” This is one job that he and his colleagues spent months working on. For example: to adequately assess visible defects in the volume model, Klaffenböck had the conspicuous areas on the test object ground down layer by layer and studied with a light microscope. The engineer has filed the results and what his team has learned in innumerable folders. And that‘s not all. These records also contain the series of measurements for positioning the cast parts in the CT scanner. The components to be measured are generally not the same size and do not have the same thickness. Thus metrology experience is necessary to ensure that the workpiece alignment delivers an optimum result in the CT scanner. “Achieving the desired level of precision and a valid result with the CT scanner required a lot of additional preparatory work,” says the enthusiastic Quality Manager. The number of binders lining the walls of his office truly does speak volumes. Demmelmair and Klaffenböck are bringing their CT know-how to the CT-Real research project headed by the Austrian  Gießerei-Institut. One of the project‘s focal points is on developing a standard for the reliable measurement of die cast parts with a computer tomograph. Klaffenböck illustrates by just how much his company is leading the way in terms of expertise: “By being an early adopter of this new technology, we have a two to three-year lead in our industry. This know-how has helped ensure the future of this site, because we can calculate process defects on the manufactured part at the beginning of the value chain.” This does not mean that the young engineer is not thinking ahead to what comes next. Reducing the measuring times with the CT scanner is at the top of his to-do list. “This is a challenge we can only tackle with ZEISS’s assistance,” says Klaffenböck, who is as enthusiastic about the partnership with the optics company as Demmelmair. “The team from Oberkochen were the only ones who wanted or were able to realize flexible automation and the high degree of system precision for cast parts.” On top of this, the company had been collaborating with ZEISS for decades. All 16 coordinate measuring machines and the two microscopes are ZEISS systems, as are the styli and the temperature monitoring system, ZEISS TEMPAR. “Bundling ZEISS expertise has resulted in outstanding synergies,” says Klaffenböck. Thus we can use the measuring programs written in CALYPSO for the virtual inspection of the characteristics from the volume models created with the ZEISS METROTOM with only minimal adjustments. “This not only saves us time,” says Demmelmair.

“We, along with our quality-conscious customers, can be certain that our measuring results are right thanks to the ZEISS solutions‘ level of precision. Now that we have learned to perform accurate measurements with the CT scanner, we will start using this technology to inspect cast parts inline.” ZEISS PiWeb is used to conduct statistical analyses for the approximately 250 measurements performed each week. The quality experts know the length of the ramp-up phase for these die cast machines which exert up to 2,800 tons of force. “This knowledge helps us optimize our manufacturing processes and thus prevent rejects,” says Demmelmair. “I see computed tomography as a key part of keeping TCG and its manufacturing sites in central Europe ahead of the competition.”

For more information: www.zeiss.com