Future-orientated advice
In order to be able to clamp components as reliably and efficiently as possible, the right clamping device must be found for each workpiece pool. Fraune Metallbearbeitung, which initially relied on fixed-jaw clamps, showed just how crucial advice can be in this regard. Reiner Hartmann from Gressel made the Delbrück-based company rethink its approach. A reorientation that has proven to be a sound investment to this day – for example in the assembly of an automated 5-axis machining centre.
Fraune Metallbearbeitung is a provider of machining services that sees itself as both a development supporter and idea realiser. From design consulting and feasibility studies to the creation of initial sample test reports, the company supports its customers in all phases of value creation and quality assurance. Above all, it also ensures that projects are implemented in a customised manner. In the further development of its product portfolio, Fraune supports customers from the mechanical engineering and motorsport sectors as well as representatives of the medical technology and aerospace industries.
For machining, the Delbrück-based company utilises a technology park consisting of 3-axis and 5-axis machining centres, turning/milling machines and 3D CAD/CAM systems. In combination with tactile 3D measuring technology, the company is able to produce complex geometries with high precision – from prototype to series production. Fraune supplements these capabilities with services such as 2D laser cutting and welding for component production as well as surface finishing by anodising, electroplating, galvanising, chrome-plating or powder coating.
A decision is pending
The company was founded in 1991 by Martin Fraune as a side business, initially serving individual and small commercial customers with conventional turning and milling, surface and cylindrical grinding. In 2012, his son Heinrich joined the company and has been consistently driving the switch to CNC technology ever since. The first 5-axis machine arrived in the same year. “That was also the moment when we decided on a specific workpiece clamping technology,” says Fraune. With fast and fixed jaw clamps, there were several options, which of course also included the costs. For his father, however, it was clear: “You can buy cheaply now, but then you’ll have to look into the subject again at some point. Or you can buy from Gressel and have peace of mind.” That’s exactly what happened. The fact that the junior boss was right with his decision is shown by the fact that the tensioner from back then is still in the race today. After almost 13 years of service. “He has earned his money and continues to do so,” says Fraune, referring to Gressel’s “Gripos”.
The balance sheet is clear
The decisive factor in the decision in favour of the quick-release clamp was above all the advice from Hartmann, Sales Technician DE North & East at Gressel, who first showed Fraune the flexibility of the system. “I was about to get into embossing technology. Thank God I didn’t, because we are far too broadly positioned with our parts. In 90% of cases, that wouldn’t have worked,” he says with relief. Hartmann adds: “When a young entrepreneur has bought a new machine and is fighting for every cent, you need powerful arguments.” Because the fixed-jaw clamp is generally considered to be somewhat more precise, this also included proving that the Gripos achieves the required precision over the long term. And that with a wide variety of applications and materials, ranging from mild steel and aluminium to brass and copper – not even counting exotic materials. And all this in dimensions of 250 x 250 x 250 mm and batch sizes from 1 to 1000. Today, Fraune has long since summarised: “It is the most flexible vice we have to date.”
Consistency in automation
In order to meet the demands of various customers for series production, Fraune still has to grow regularly. This is flanked by automation, whereby experience has shown: The automation of existing machines is often associated with unplanned consequences. When the last purchase of a 5-axis machine was due, Fraune soon favoured a complete solution from Hedelius. “Overnight and weekend production would not have worked with a retrofitted existing machine,” he is convinced. The automation of the “Acura 65”, on the other hand, was secured with an extensive tool magazine. There was also a pallet storage system for 22 pallets and a further 12 for pre-setting. For workpiece clamping, Fraune once again relied on the universal systems from Gressel. “Today, we prepare the respective clamping devices, set them up on the Hedelius pallets and work with a wide variety of batches. For example, a series part is placed on pallets 1 to 14, while the other eight are used for variable production using a zero-point clamping system.” The Delbrück-based company also works unmanned in this constellation. “We retool accordingly so that the machine can work autonomously at night or over the weekend.
Variable clamping of workpieces
The parts are usually machined in a first clamping operation, then reclamped and the other side machined. Nothing unusual then. On the Acura, centric clamps “C2.0” in size 125 are used for this. The fact that Fraune has “never had any problems” with them is due to the high clamping force of up to 35 kN as well as the high precision. “At the same time, many conversion options can be realised quickly,” reports Fraune. “For example, the installation of two centric clamps or the use of floating jaws. This allows us to turn the C2.0 into a 4-fold clamp and produce 88 parts with 22 pallets.”
The Delbrück-based company also regularly works with the “gredoc” zero-point clamping system, with which various clamping devices can be used with particular flexibility. The C2.0 125 always forms the basis for first-side machining. However, shorter versions are also used. The C2.0’s little brother, the “SC2.0” fixed-jaw clamp, is also used for moulding clamping. Finally, the small “C3”, the latest centric clamp from Gressel, is used in the measuring room alongside the C2.0. “When my colleague saw the C3 for the first time, he immediately put it on his measuring machine.” The fact that he also uses the gredoc once again demonstrates the consistency of the Gressel systems.
Positioned for the future
“In order to fully utilise the potential of automation with the Acura 65, Fraune thought bigger and had the 5-axis machine equipped with a large tool magazine, a large pallet storage system and universal clamping devices,” summarises Michael Jürging, Managing Director of the machine tool and machining technology company of the same name, which distributes Hedelius as well as Gressel. “In doing so, we have remained true to our motto of always doing everything in-house,” adds Fraune. “If we take a step forwards in production, we do the same in other areas wherever possible.” And here he means the measuring room. Consultancy is always important. “For example, when manufacturing a component, we went from a cuboid to a round part. After a tip from Reiner Hartmann, we were able to increase this to 16 parts with eight pallets and two gredocs.” Hartmann sometimes receives a sample part by post for which a solution needs to be found. For small parts, for example. “When the C3 arrived, we initially didn’t trust it to do any machining. We had concerns about the stability and holding forces. Now we know: It’s really great. Especially in terms of accessibility.”
Fraune is well positioned for the future when it comes to workpiece clamping technology. Especially as it works like Lego: If there is a special component, for example, the appropriate additions can always be built onto the gredoc. “We are therefore pleased that we have also moved in the direction of the zero-point clamping system with the centric clamp. Starting from the Gressel modular system, the systems can be expanded from end to end.”
Contacts
Gressel AG
Schützenstrasse 25
CH-8355 Aadorf
Telefon: +41 52 368 16 16
E-Mail: info@gressel.ch
Web: www.gressel.ch
Fraune Metallbearbeitung GmbH & Co. KG
Untereichen 15
D-33129 Delbrück
Telefon: +49 5250 8873
E-Mail: kontakt@fraune-metallbearbeitung.de
Web: fraune-metallbearbeitung.de
