Modern Machine Shop
Doosan’s Lynx 220LMSA turning center features a subspindle, live tooling and a longer bed that accommodates parts as large as 9.45" in diameter by 20" long. Designed for heavy cuts in difficult materials, the machine is equipped with a gearless, 20-hp AC spindle motor that can achieve a maximum torque of 93.6 foot-pounds in seconds, the company says. The spindle motor is aligned with the headstock and controls both the spindle in two-axis mode and the full-contouring C axis in three-axis mode.
The one-piece bed is strategically ribbed to maximize rigidity, while its fine-grain Meehanite composition absorbs vibration and helps dissipate heat, the company says. The bed’s 30-degree slant angle is said to provide a short and constant distance from tool tip to guideway, easy access to the chuck, turret and spindle, and efficient flow of chips and coolant to the chip bin.
The linear-motion guideways are widely spaced for stability and provide X- and Z-axis rapid traverse rates of 1,181 ipm and 1,417 ipm, respectively. A four-row, circular-arc configuration supports the same load capacity in all directions. Precision ballscrews are centered between the guideways and mounted directly to the AC servomotors to reduce backlash from intermediate gears or belts. A torque limiter clutch senses abnormal loads and immediately stops axis movement. Repeatability is ±0.00008" along the X axis and ±0.00012" along the Z axis.
The 24-position turret accepts live, BMT 45P tooling at each of its 12 stations. A 5-hp, rotating tool spindle motor generates speeds ranging to 6,000 rpm and as much as 17.3 foot-pounds of low-end torque. The bi-directional tool selection system offers 15-sec. station-to-station indexing with index repeatability of ±0.0005 degree.
Automatic forced lubrication, with a 100 hr. lubricant reservoir, is delivered to all guideways and ballscrews through non-clogging pistons. A 1.2 hp centrifugal pump delivers coolant through the turret to ball nozzles at each turret station.