Achieving Power and Flexibility with INOFlex®

What do a cocoa press, printing machine and wind power plant have in common? Very little, except that all three contain parts machined by Kersten Maschinenbau using HWR INOFlex® clamps.

Located in Niederau, Germany, Kersten Maschinenbau GmbH has built a competitive advantage out of maintaining the capabilities needed to manufacture an incredibly diverse range of parts. To accomplish this, the company relies on the expertise and reliability of its staff, an ultra-modern range of machines and the INOFlex® compensating, centrically clamping four-jaw chuck from HWR.

Established as a craft company in 1965, Kersten reorientated itself as a machine construction supplier after German reunification. In 1990, the company was staffed by 15 employees and made the choice to invest in its first CNC machining center. Today, Kersten employs 130 and houses more than 30 ultra-modern machines.

For Kersten, flexibility and efficiency are major concerns, and its technical equipment plays an important role in achieving these. For example, the machine construction supplier realized that it needed a more advanced clamping system to manufacture diverse high-precision components. When evaluating its options, Kersten noted that the clamp needed to be easily accessible for tools and also ensure flexibility and operator safely. Dipl.-Ing. Mathias Scheel, head of production planning and tool preparation at Kersten, believed he might have found a solution in the HWR INOFlex® VL chuck.


INOFlex® is a universal, compensating, centrically clamping four-jaw chuck. It securely clamps  round, rectangular and geometrically irregular parts from 160 to 1,200 mm in diameter, making it an ideal solution for shops producing a wide range of part types.

“What I immediately liked was all clamping jaws of the four-jaw chuck resting in a compensating manner against the workpiece, from the operation of only one spindle, and that this workpiece centres to the middle”, recalls Mr. Scheel. “And we were, of course, extremely interested in the possibility of clamping round, cubic and geometrically misshaped workpieces with a single clamp.”

Soon after discovering INOFlex, Kersten was operating three of these flexible chucks: a 400 manual chuck, 700 VL chuck and 420 VL.

“We are very satisfied with the INOFlex® chucks”, says Mr. Scheel. “The quality of the products is fine and the patent of the compensating four-jaw chuck functions flawlessly.”


Many of Kersten’s parts previously had to be clamped using intricate clamping iron or magnet clamping plate fittings. Switching these applications to INOFlex has provided significant setup time reductions. Today, the company deploys INOFlex wherever traditional clamping devices are nearing their limits. It has found the chucks to be especially helpful in improving the concentricity of thin-walled parts.

Kersten also was able to increase process security and safety with INOFlex. Applications on the company’s Alzmetall GS1400 turning/milling centers provide an excellent example of this.

“For safety reasons, it was not possible to use the turning function given several clamping operations,” says Mr. Scheel. “This is now quite easy thanks to the INOFlex clamp.”

INOFlex also improves flexibility by allowing parts to be machined on five sides. Setup times have been shortened and the company appreciates how easy it is to load blanks. Such loading only requires the operators to clean the supporting parts and then insert the next workpiece.


In addition to the two Alzmetall GS1400 turning/milling centers, Kersten applies the INOFlex® VD400 manual chuck on practically every machine in the turning shop.

The company’s own production of special purpose brackets allows the compensating INOFlex VL070 and VL042 four-jaw centering clamps to be mounted directly onto the maching table or  via the zero-point clamping system installed on almost all machining centers.

“As a result, the VL070 can be fitted on our two Alzmetall GS1400s, the Reiden RX18, Hermle C50U, Hermle C42U, Ibarmia ZVH58 and all three-axis machining centers,” says Mr. Scheel. “And in addition to the above, the most recently bought VL042 can be fitted on our two Hermle C800Us, where it replaces the somewhat older three-jaw chuck that has had its day.”


“The fact that we constructed the base plates ourselves was important”, says Udo Kersten, CEO of Kersten. “The best thing is that HWR has been absolutely flexible at all times.”

“The the quality of the 3D-data provided is something we find very good,” adds Mathias Scheel. “We need precision 3D models to draw up the clamping plans and CNC programs in the production planning phase. This provides us with the basis to precisely and realistically simulate each machining situation and the interaction with machine and tool models in advance.”

The integrated vice functions with one or two fixed stop jaws allows the customer – apart from the compensating four-jaw chuck – to use the product as a vice, fixed stop clamp or two-jaw clamp.

The incredible quality and abundant flexibility of the INOFlex system have provided Kersten with precisely what it needs: the ability to quickly respond to orders from customers that require parts diverse in their size, geometry and requirements.

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