CNC Turning Centers Offer Improved Performance, Accuracy and Reliability
The compact Puma GT2100 series from Doosan includes 8 in and 10 in turning centers that deliver 60 percent more feed thrust for larger drilling capability with minimized cutting vibration and extended tool service life.
Doosan Infracore Machine Tools’ (Pine Brook, NJ) all-new compact Puma GT2100 series include 8 in and 10 in turning centers, incorporating the key advantages of the popular Puma 240 in a more compact and cost competitive package, with improved performance, accuracy and reliability.
Swing over bed is 23.6 in, and swing over saddle is 15.4 in. The maximum turning diameter is 15.4 in, while the maximum bar working diameter is 3.2 in (Puma GT2100(M)B). Maximum turning length is 22.1 in.
An overview of the Puma GT2100.
The 30 deg single-piece slant-bed design reduces the center of gravity of both spindle and cross slide by 12 percent. The natural frequency (NF) — the amount of structural vibration — is a critical factor that affects the machine’s contouring performance and surface finishes.
The NF of the Puma GT2100 bed is 42 percent higher, delivering greater dynamic stability in high-speed operation. Cast design optimized with 3D computerized analysis delivers stable cutting performance with minimized cutting vibration and extended tool service life. Wide ribs and a box-type slideway further reinforce bed rigidity.
An optimized spindle overhang design has minimized the rotational inertial load, enhanced rigidity, and shortened acceleration /deceleration time. Spindle motor is rated at 25 hp. Maximum spindle speed, 4,500 rpm. Rapid travels: 945 ipm (X-axis) and 1,181 ipm (Z-axis).
There are numerous accuracy and performance improvements on the Puma GT2100 series. A larger Z-axis servomotor delivers 60 percent more feed thrust resulting in larger drilling capability. The spindle design features three angular ball bearings in the front and cylindrical roller bearings in the rear, which minimizes thermal growth and increases precision.
The spindle is also shorter for reduced acceleration/deceleration time. The spindle drive belt length has also been reduced contributing to less belt stretch, higher milling accuracy and less belt vibration.
Efforts have also been made to reduce the number of parts, making the design simpler and more reliable. The turrets are a good example. The number of parts has been reduced up to 53 percent. Pulleys, belt and intermediate gears have all been eliminated on the Puma GT2100 and have been replaced with a larger servomotor — a design that is simple, reliable and fast.
Other features include the number of tool stations, 12; OD tool size, 1.0 in x 1.0 in.; maximum boring bar size, 1.6 in; turret indexing time, 0.3 sec.
The BMT55P turret (Puma GT 2100M) tooling is strongly fixed to the turret with four bolts and keys to provide powerful machining performance with high efficiency, high rigidity, and a high precision internal drive system. Stable performance is guaranteed even after extensive milling work. The rotary tool speed is 5,000 rpm with a 7.5 hp rotary tool motor.
The milling turret design has a bevel drive gear and air /oil cooling. The design provides low heat generation, minimizing thermal growth, while providing silent vibration free performance. Increasing the hose size and eliminating intermediate manifolds improve coolant flow rate. Higher flow rate improves cutting performance.
The operating console features a Doosan-Fanuc i control with a large 10.4 in color TFT LCD monitor with PCMCIA Card, USB port, embedded Ethernet connectivity and a swing-type panel (88 deg swing).
Doosan EZ Guide i is included as a standard feature, offering shop floor conversational type programing. Roughing, finishing, castings, grooving, threading, peck drilling and more are all accomplished through EZ Guide’s menu driven functions. Programs are easily generated using cycles instead of long hand code.
Further, the Puma GT2100 is easier to load. Distance from front cover to spindle center is reduced from 17.2 in to 15.3 in. And finally, for a machine with similar specifications, the Puma GT2100 series are 14 percent to 25 percent more compact than the previous models. Cost of floor space does impact the hourly operating cost and, in many cases, shop floor real estate has become an important issue.
The Puma GT2100 guarding has been designed to provide easy access for adjustment, maintenance and service. The chip conveyor design bolts directly to the machine allowing the chip pan and coolant tank to slide out independently. This design eliminates coolant leakage and makes it easy to access and clean the tank. The tail stock guide ways on the Puma GT2100 series are covered and fully protected from chips. This eliminates the ongoing cleanup time required on previous models.
Energy savings is achieved by using a 23 percent more efficient hydraulic unit. An LED work light is now being used, which lasts 10 times longer than the previous halogen type and generates little heat. This helps to keep the work area a little cooler and thermally stable. LED lights also consume much less energy. Auto power-off functions further reduce power consumption and heat.