Premium clamping devices ensure process reliability

The contract manufacturer Schittl from Deutsch Kaltenbrunn specializes in the production of one-offs and small series projects. Based on a recommendation from the multi-brand dealer Metzler, they use chucks from BIG KAISER. This is their story.

"Fast, flexible, precise" is how its Managing Director, Roman Gradwohl, describes the specialist machining company Schittl. Located in Burgenland, Austria, this contract manufacturer supplies customers from Austria and Germany with precision parts, with a focus on prototypes and small series runs for standard mechanical engineering applications.

Customers benefit from a wide range of services, including turning, milling, mill-turning, measuring, all performed on CNC machines controlled using the latest CAM programs. From 1000x1000 mm 5-axis simultaneous machining to the smallest die sinking EDM parts, Schittl covers a very wide range of tasks and sizes.

The machinery is operated by a young, well-trained team. "We have a flat hierarchy, with 5 senior managers and 57 employees. Instead of a plant manager, we have had success with self-managed machining groups. Every employee has been trained to operate a machine as well as perform CAM programming tasks and, therefore, has the flexibility to independently decide whether to program off-line or perform a simple machining task directly on the machine. Everyone is very motivated by the high degree of personal responsibility," says Roman Gradwohl.

The company's ultra-modern fleet of machinery includes equipment of all sizes to provide customers not only with optimal results but also optimal hourly machining rates," explains Roman Gradwohl. "It is important for each individual part to be machined on the most suitable machine. A simple 3-axis milled part does not have to be manufactured using a 5-axis simultaneous machining center. Just because something is physically possible doesn't necessarily make it the optimal solution."

Roman Gradwohl has been successful in applying his recipe of combining modern machinery with highly trained, motivated employees. And he knows the contract manufacturing market inside out: 

"Today, delivering quality is a pre-requisite for all manufacturers. This applies both to us as well as price-focused competitors from other countries. Nevertheless, we provide the guarantee that a quality product is delivered first time, every time, and there is no risk of products needing to be reworked. We are able to offer reasonable delivery deadlines and our customers have the peace of mind that they can rely on us."

Schittl needs many kinds of tools for the smooth operation of its extensive machine park. For this purpose, the company works closely with the solution-focused multi-brand dealer Metzler. Machining has been part of the core competence of this renowned Vorarlberg company for well over a quarter of a century. It holds over 100,000 items on stock.

Harald Gelis, Head of Profiteam Cutting at Metzler, explains the procedure in more detail, "Of course, we have several suppliers for most tools. However, when it comes to special requirements, we always prefer to recommend the products from BIG KAISER. Especially when clamping taps and reamers, we need premium tools to ensure the highest possible process reliability."

Process optimization through better handling

The fit of a bored hole is always a critical point. In the past, Schittl manufactured these with reamers in precision collets. Although this approach proved to be precise over many years of operation, it also required a great deal of maintenance. Tools needed to be cleaned after each use, which due to the long slots could become relatively costly. When a chip gets jammed inside, the production process can suffer significant disruptions as the clamping force and concentricity are massively impaired.

"I recommended the HMC power chuck from BIG KAISER," remembers Christoph Pum, Specialist Salesman for Cutting at Metzler. "They're simply unbeatable in handling."

The New Hi-Power Milling Chuck, also affectionately known as HMC, is a high-performance power chuck that provides high concentric accuracy due to its design and mode of action. Defined slots in its body ensure the even deformation of the chuck and thus guarantee an even and strong clamping force. The key benefit: handling becomes far easier, since there is no way for chips to jam inside the HMC. The uncomplicated, narrow and straight shape of the chuck means that the slots are not susceptible to jamming. Furthermore, this makes them easier to clean, for example when changing diameters. As the possibility of overlooked debris become less likely, clamping process reliability can be guaranteed with a greater degree of confidence.

"At first, I was quite skeptical whether the concentric accuracy of the power chuck would be sufficient for our precise fits," admits Roman Gradwohl. "However, when we tested it, repeatability and handling were more than convincing. The factory specifications were consistently surpassed. In addition, the holder is ideally suited for milling."

A welcome side effect of the high quality of BIG KAISER tools: Schittl clamped not only reamers in the chucks but also experimented with their HPC milling cutters. Thanks to the tools' strong damping ability, perfect surface quality could be achieved even at higher machining speeds. "Today, we have practically eliminated the use of indexable insert cutters," reports Roman Gradwohl.

Process safety

"Another challenge at Schittl is reliable threading," notes Harald Gelis. "Machine tapping of threads requires that the rotation of the tap must perfectly match the feed rate. It lacks a degree of freedom, so on systems without length compensation, it often happens that the tap breaks off due to high lateral forces. The production process is thereby significantly disrupted and the workpiece can easily be ruined. The MEGA Synchro tapping holder from BIG KAISER compensates for synchronization errors during rigid tapping by means of automatic length compensation. The occurring lateral forces are reduced by 90% without limiting rotational stiffness. This is enabled by the synchro adjuster, a special rubber sleeve that permits a defined shift."

"A scrap part does not only mean high costs for us," explains Roman Gradwohl. "For batch sizes of 1, a defective workpiece simultaneously results in a rejection rate of 50 percent. We can't afford to be practicing on such projects. It's got to hit the mark on the first try. For this reason, the MEGA Synchro tapping holder delivers a rapid return on the higher investment costs and enables us to meet tight delivery deadlines."

Modularity supersedes special tools

The MEGA Synchro tapping holder can be extended with modular spacers to provide good accessibility. Spacers are fitted to ensure perfect concentricity even with large extensions. Even though it is a modular solution, BIG KAISER provides optimal cooling characteristics. Each extension is hollow-drilled to supply the coolant to the tool.

"I was particularly impressed by the modularity of this solution. Prior to this, we had separate special tools for each specific case. The problem was, however, that having to order special tools for each individual project would prevent us from meeting the demanding deadlines that we are set. With the new modular solution from BIG KAISER, we are able to offer our customers rapid, quality solutions even on special projects. What's more, the extensions function seamlessly with any MEGA Synchro tapping holder, regardless of the type. Our large fleet of machines has four different spindle standards. That's a whole lot of tools saved."

BIG KAISER has a product line of 48 basic holders and 182 tapping holders. Each of the resulting thousands of possible combinations replaces a special tool.

Goals achieved thanks to the right tool solution

Harald Gelis is certain of one thing, "We have found an excellent solution for Schittl. With the HMC milling chuck and the MEGA Synchro tapping holder from BIG KAISER, their workpieces are not only produced in exceptional quality but also economically with reduced complexity, but most importantly with process reliability".