Hankook Machine Tools Co., Ltd. adopts REDEX ANDANTEX’ DualKRP+ Drives for its newest Rack & Pinion Type Roll Lathes!
Hankook Machine Tools, the machine tools industry leader in Korea, successfully developed and launched the marketing campaign for its new roll lathe R-50W equipped with the DualKRP3+ from REDEX ANDANTEX, the European high-tech rack and pinion planetary drive manufacturer. This lathe provides more precise positioning and overcomes the limited Z-axis movement of existing ball screw-type lathes.
Hankook Machine Tools Co., Ltd., established in 1969, is a forerunner of the machine tools industry with excellence in its in-house research and development capability. Since the development of the first large-scale lathe based on Korean components and technology in the mid 1980s, Hankook Machine Tools has enjoyed a close partnership with major manufacturers in the steel, shipbuilding and other industries for over 25 years through its excellent performance and reliability.
Hankook Machine Tools operates its own multi-product small-volume production facility in addition to a portal machining center to handle all its production orders for CNC horizontal lathes, CNC vertical lathes, CNC roll lathes, semi-CNC lathes, and conventional lathes. Hankook’s up-to-date production organization is capable of producing over 1,000 units annually.
Hankook Machine Tools recently launched its new product R-50W. This rack & pinion type roll lathe provides more precise feeder positioning and overcomes the limited Z-axis movement of existing ball screw type lathes. Following successful development of the new lathe, Hankook is going ahead on its product marketing and distribution. This equipment max. turning diameter is 2,200 mm, the max. processing length is 15,000 mm, and the load capacity between centers is 50 tons. In addition, R-50W complies with the ISO-1708 class precision standards.
For developing this rack & pinion type roll lathe R-50W, Hankook Machine Tools needed to use a drive combining both extra-high stiffness and true zero backlash.
That was the reason for Hankook Machine Tools to choose REDEX ANDANTEX, the European high-tech rack and pinion planetary drive manufacturer.
REDEX ANDANTEX’ DualKRP+ is a high-tech planetary drive which allows easy implementation in various forms. It performs exceptionally well in gantry type machines of portable columns. Based on a two planetary drives design, the DualKRP+ includes the mechanical preload system to ensure full cancellation of the rack & pinion backlash.
DualKRP+ also features the REDEX ANDANTEX-invented fully integrated output pinion technology that provides the exceptional compound stiffness which is essential in high demanding rack & pinion drive applications. This product line offers six universal sizes as a standard. Its implementation is quite easy due to the innovative and compact design.
“Our thorough comparison with competing equipments using REDEX ANDANTEX’ devices, as well as equipments using devices from other drives manufacturers revealed that REDEX ANDANTEX’ solution perfectly fits the specification requirement for our machine,” said Hankook Machine Tools’ Director Kim Dongseok. “Not only does REDEX ANDANTEX have a wide range of products that meet all the various specification requirements we might ask for, but in addition all their products showcased a high level of performance and reliability.”
Kim explained, “we asked for a design specification including travelling distance up to 15,000 mm, angular backlash precision better than 4 arcsec, speed up to 4 m/min, and max. feed force higher than 35,000 N.
REDEX ANDANTEX met all our specification requirements. Their highly reactive technical support service also allows us to be in effective partnership in terms of product quality control.”
Unlike the previous ball screw type lathes, the rack & pinion type lathe R-50W drive includes the gearbox by design. It makes the installation very easy as the gearbox does not need to be installed separately. In terms of travelling distance requests from the customers, simply extending the bed length practically provides unlimited Z-axis movement. This unprecedented level of flexibility allows a wide range of applications. In addition, a linear encoder can
be used to add a closed loop position control to the system and to improve the positioning precision.
Hankook Machine Tools’ roll lathe R-50W is currently targeting the steel and shipbuilding applications. Two units have already been delivered to customers. It is now expected to reach even wider range of applications as it was designed with flexibility in mind, allowing customizing for different environments and specifications. Hankook is currently developing another roll lathe R-70W which again includes REDEX ANDANTEX’ high-tech planetary drives DualKRP4+.
REDEX ANDANTEX’s solutions are successfully implemented in Korea, but also in China, Japan, the USA, Germany, Italy or Spain.
Figure 2. The R-50W’s max. roll turning diameter is 2,200 mm, max. processing length is 15,000 mm, and the load capacity between centers is 50 tons.
Figure 3. REDEX ANDANTEX KRP’s internal structure. The rigidity of KRP+ is a consequence of its design with integrated output pinion and reinforced output bearing. The output pinions are machined to the same diameter as the shafts, giving the optimum compromise between transmissible torque and rigidity at the rack. The output bearing consists of two preloaded and substantially oversized angular contact roller bearings. This construction enables the bearing to support the pinion as close as possible to the force, as only the thickness of the fastening nut separates the pinion from the output bearing. This design considerably reduces radial bending, which is responsible for 60% of overall distortion but is nevertheless still poorly handled by existing systems. The result is increased dynamic precision thanks to its capacity to displace heavier loads at higher speed. Its performance in terms of stiffness combined with its low inertia enable higher accelerations (up to 25 m/s2). As a consequence, the resonance frequencies of the drive systems in which it is incorporated can be raised significantly.
Figure 4. REDEX ANDANTEX DualKRP