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Convincing performance and quality

The target oriented use of tool holders provides process improvements and cost benefits

The importance of tool holders for a reliable machining process is well-known in the manufacturing department at GDELS-Mowag in Kreuzlingen. Therefore, the responsible people rely on HAIMER products, such as the vibration- dampening Power Shrink Chuck and the very precise Cool Flash tool cooling system. The result: more reliable chip removal, better surface quality and up to 30 percent longer tool life.

Lake Constance is well-known for whitefish and perches – but also for Piranhas. Surprised? Okay – these piranhas are not fish, but light, protected wheeled vehicles built by General Dynamics European Land Systems – Mowag (GDELS-Mowag) at their plant in Kreuzlingen, Switzerland. A specialty of this Swiss plant is the power transmission for which it operates as a group-wide competence center.

Josef Erlacher is a CNC programmer in the machining department consisting of 100 employees. There, almost everything is produced in-house – from the simplest wave to cubic parts and complex bevel gearing. He explains: “We produce a lot of know-how parts which is why we have a very high production depth. In addition to turning machines and machining centers we also have facilities for grinding, gear milling and hardening.” He points out another advantage of the in-house production: “Since we hardly rely on suppliers, it is in our hands to always provide our components reliably and on time.”

Despite group affiliation and special competence – the team in Kreuzlingen is always subject to high cost pressure. Therefore, they are constantly examining how to improve their processes in order to save time and money. In doing so they not only focus on machines and tools but also on tool holding – i.e. the often underestimated interface between the machine tool spindle and the cutting tool.

Josef Erlacher, who is also responsible for purchasing tools, is certain: “The tool holder bears a great deal of responsibility for the machining quality, spindle lifetime and tool life. After many years of experience we are convinced that HAIMER quality is outstanding. This is why we at GDELS-Mowag constantly use HAIMER tool holders for drilling and milling the cubic parts.” Josef Erlacher further emphasizes that in the past he had bought other, cheaper holders which could not meet his expectations. The machining specialist explains: “This is why we quickly returned to HAIMER products.”

HAIMER GmbH headquartered in Igenhausen, Germany is a family-owned company which in the past 40 years has become the world market leader for tool holding technology and is now acting as a system provider for tool management.

Advantages of vibration dampening tool holders with special cooling

Josef Erlacher knows that HAIMER invests a lot of its resources into research and development and continuously improves its products. Therefore, he is always open for innovations which promise process improvement. Four years ago Dihawag, the local HAIMER distribution partner in Switzerland, showed him the new HAIMER Power Shrink Chucks with Cool Flash for the first time and he immediately agreed to do a test run.

The Power Shrink Chuck differs from the Standard Shrink Chuck through its optimized design which combines high rigidity and vibration dampening. This increases the cutting performance while protecting the machine, spindle and tool. With the HAIMER Cool Flash system, the coolant directly reaches the cutting edge of the tool and eliminates balls of chips. The coolant bores are installed in the tool holder with which the coolant is transported up to the face surface of the chuck. A special design creates high pressure and distributes the cooling lubricant over the entire circumference of the tool shank. At the end of the shank area, the coolant is pressed into chip flutes (adhesion), rinses them free and even at the highest speeds it reaches the cutting edges directly, without sputtering, where it can unfold its cooling effect.

The overall system Power Shrink Chuck with Cool Flash made an impact in the machining department at GDELS-Mowag. Andreas Haug, also CNC programmer at GDELS-Mowag explains: “Although we do not use high speed cutting we have to machine extremely difficult materials.” With these new HAIMER shrink fit chucks we can achieve more reliable chip removal, better surface quality and a much longer tool life of up to 25 to 30% at the same cutting parameters.” His colleague Josef Erlacher confirms: “In the past we used to have problems with chip congestion. With Cool Flash this problem belongs to the past. The chips are removed reliably and the tool is cooled continuously. This is why we switched to work on all challenging operations by using Power Shrink Chucks and the Cool Flash system. Also, whenever we have to make new acquisitions, this combination is our first choice.”

Wide range of HAIMER products for target-oriented use

However, Andreas Haug points out that standard shrink fit chucks are still very effective and used for drilling, reaming and so on. “The use of HAIMER chucks at our facility is very target oriented. Decisive factors are the type of the machining application and the material we work with, which is often very exotic at GDELS-MOWAG. We frequently work with quenched and tempered steel with a strength of up to 1400 N/mm2, where high temperatures occur at the cutting edge. Our special cast materials are also challenging, for example a very abrasive grey cast iron with a tensile strength of 1000 N/mm2. With the HAIMER Power Shrink chuck and the Cool Flash system, we noticed significant process and cost advantages milling these kind of materials.” Josef Erlacher adds: ”We could probably realize higher cutting values, but especially the complex parts for which we use the Power Shrink Chucks are extremely expensive which is why we do not want to take any risks. Since the produced quantities are so low, shortening the processing time is not as important as the other advantages.”

All HAIMER products are produced according to the company philosophy ”Quality Wins”. Josef Erlacher explains: “We are still using shrink fit chucks that are 12 years old and still work perfectly.” The same applies to the Power Clamp shrinking machines. In 2017, GDELS-Mowag replaced its now 13-year-old device with a new HAIMER Power Clamp New Generation (NG). Its essential feature is the intelligent, patented NG coil, which is very flexible and easy to handle. With a simple twist you can adjust the length and diameter to the size of the shrink chuck. There is no need for stop disks. This way, standard or special sized chucks are only heated at the right spot. Erlacher explains: ”Even though our old device was still working perfectly, we are faster with the new one. With a two-digit number of shrinking operations per day, the investment is definitely worthwhile.” Furthermore, there is always a replacement device available for emergencies.

Well-equipped for the future

For GDELS-Mowag there is no doubt that the future of machining will be heavily influenced by digitization. For some time now, Josef Erlacher, Andreas Haug and their colleagues have been busy digitizing their processes. However, they point out that harmonizing the different systems is very important. “We need consistent data flow from CAM to the machine tool. HAIMER is supporting us in this regard, for example, by supplying the digital models for all chucks as 2 and 3D data.”

General Dynamics European Land Systems – Mowag

…belongs to the General Dynamics Corporation, a US global corporation. The headquarters of GDELS is located in Madrid. Currently around 1800 employees are working at the GDELS branches in Germany, Austria, Switzerland, Spain and the Czech Republic. The products range from wheeled armored and tracked combat vehicles to amphibious bridges and ferry systems. The Swiss plant in Kreuzlingen currently employs around 800 people where light tactical and protected wheeled vehicles such as the Piranha, Duro and Eagle are built. In addition, Kreuzlingen is the worldwide competence center for power transmission.