When hydrostatic-driven guideways first came on the scene, they were lauded for their abilities to reduce friction and for their good damping behavior in machine tooling applications. Although more expensive than machines using conventional ball or roller-based linear guides, the benefits of grinding machines equipped with hydrostatics – including the ability to carry heavy loads and the high robustness - were too compelling to ignore, and the machine tool industry soon embraced the technology. In fact, for thirty years Hardinge has been using hydrostatics in our grinding machines to achieve higher productivity, increased precision, and improved response time.
Why use Hydrostatics?
While hydrostatics-based grinding machines may cost more initially, many machine shops are willing to pay the price to be able to produce parts in one-step into tolerance and with less wear and tear on the machine itself. No wear and tear can substantially increase the longevity of the grinding machine, enhancing ROI by extending the useful life of the equipment.
Not to be ignored is the improved productivity which can be achieved with the hydrostatic system’s design. With conventional machines, moving components ride on way systems using rolling elements that produce metal-to-metal contact. In contrast, the moving part of a hydrostatic way system “floats” on a well-defined pressurized film of oil on top of a precision-grinded surface. Oil is pumped into pockets on defined positions to build up the oil-film and to guarantee high system stiffness. By suspending the moving part in oil, the hydrostatic machine has negligible friction in the free-direction of the axis. Stick-slip-Effects at low feed rates during finishing of the part cannot occur.
Effective Vibration Damping Delivers Improved Results
By avoiding direct surface-to-surface contact in grinding applications, hydrostatic guideways can improve weight-carrying capacity and maintain a low-friction experience during machine movement. Without the friction, machine tools can accelerate more mass at a higher rate. They can also tackle applications involving wide grinding wheels and heavy stock removal.
Today, hydrostatic guide systems are improved and combine the high-quality damping of traditional designs with the performance and flexibility of rolling profile rails. As a result, hydrostatic linear guides are considered the best technical solution for vibration damping at the point of system loading. It’s important to minimize the impact of vibration in the machining process, as it can significantly degrade workpiece accuracy and surface quality. Effective vibration damping can make a big difference when you need to achieve a precise appearance, smoothness or flatness of a part.
Vibrations on a machine tool are always a function of their construction with mass positioning (static and dynamic), stiffness and the damping of the system. Under heavy load conditions – grinding quality can be critically disturbed by vibrations. For example surface quality and roundness of a part is out of tolerance because of chattering - a bad tool-workpiece interaction. In this case the damping of the hydrostatic system helps tremendously to reduce the effects vibration, because stiffness and mass position of the machine and of the tooling is limited by design.
As a result, hydrostatic-based machines are the best choice for high-speed, heavy-load machining and high-precision grinding applications. In Hardinge equipment, no-friction grinding and excellent vibration damping helps to enable the highest surface quality.
Hardinge Kellenberger 1000 - Handling Special Materials with Speed and Accuracy
In keeping with our commitment to deliver machining solutions with super precision capabilities, Hardinge offers our flagship hydrostatic-based cylindrical grinding machine, the Kellenberger® 1000. Combining functional design with high-precision technology, this CNC-controlled universal grinding system has advanced components, such an automatic cylinder correction and synchronous tailstock, that are optimized to meet the varied and demanding requirements of our customers.
The Kellenberger 1000 stands out for a number of reasons, including the excellent static and dynamic rigidity of its machine base, which permits a three-point set-up while not requiring any specific adjustments on the building’s foundations. The increased stiffness achieved with this design enables consistent sustainable productivity, done with the highest precision.
Another advantage of the Kellenberger 1000 is its compact and easy-maintenance design, with service/maintenance doors providing simple access to machine components integrated in the back. The tried-and-true integral transportation concept (hook machine) helps reduce machine commissioning times while ensuring a compact installation area. The enhanced comprehensive machine cooling system helps provide optimal temperature stability along with minimized thermal drift.
The Kellenberger 1000 machine design is crafted for big jobs, with an extended machine table that optimizes the positioning of the grinding wheel and accommodates a larger travel distance. A heavy-duty functional machine casing with increased sheet metal thickness enables more process reliability and supports a larger internal grinding wheel diameter of up to 125mm. It also can be configured for a number of specific applications used by different industries.
Along with its flexibility and energy-efficient features, the machine’s durable pre-tensioned hydrostatic make the Kellenberger 1000 a wise capital investment by delivering higher accuracy and better surface quality. Separating the machine base from the assemblies and equipping the hydrostatic guides with interpolating axes ensure high quality grinding result at faster positioning speeds. With optimum measuring-machine accuracy, the Kellenberger 1000 can complete grinding tasks with superb precision and productivity.
Hardinge – Providing the Right Machine Tool Solution and Support Every Time
With thirty years’ experience with hydrostatics, Hardinge understands the benefits and best applications for this technology. A leading international provider of advanced metal cutting solutions, we provide customers with highly reliable and technologically advanced CNC turning, milling and grinding machines and workholding accessories.