Product Spotlight

New Makino a51nx and a61nx HMCs Extend Machining Capabilities

Makino’s new a51nx and a61nx horizontal machining centers extend the capabilities of the highly successful a-series with a host of technologies that offer next-generation productivity, accuracy and reliability.

The a51nx and a61nx have larger work envelopes, higher machine strength and rigidity far beyond levels typically associated with 40-taper machines. All this, plus advanced spindles and axis guide enhancements, combines to deliver increased speed and precision in larger part applications.

Expanded Work Envelope

The a51nx and a61nx models boast expanded axis travels. The a51nx features a 560-mm (22.0-inch) X-axis and extended Y- and Z-axes of 640 mm (25.2 inches) for an industry-leading total axis volume of 8.1 cubic feet. The additional Y-stroke yields a 14 percent bigger working envelope that accommodates larger parts or more parts per fixture.

The standard a61nx features a 730-mm (28.7-inch) X-axis, 650-mm (25.6-inch) Y-axis and extended Z-axis of 800 mm (31.5 inches). An optional tall column on the a61nx expands the Y-axis to 730 mm (28.7 inches), making it beneficial for large die-cast or near-net-shape applications, which require the additional stroke but not the power of a 50-taper spindle. Thanks to the expanded Z-axis stroke, maximum tool length on the a51nx and a61nx models is increased to 430 mm (16.9 inches) and 510 mm (20.1 inches), respectively, which is advantageous for line-boring applications.

More Spindle Power

The a51nx and a61nx machines have new, more powerful standard and optional spindles. The standard spindle is a 14,000-rpm design with 240 Nm of duty-rated torque and 22 kW of continuous output, a 19 percent increase over the previous model. An optional 300-Nm spindle designed for high metal-removal rates in ferrous applications is also available, opening up new machining opportunities typically reserved for larger machines. Along with the two new spindles, the current 20,000-rpm core-cooled spindle remains available as an option on the a51nx and a61nx machines.

Higher Machine Strength and Rigidity

Casting design and axis guide improvements of the nx machines deliver higher stiffness, load capacities and precision. A new cross-roller guide design yields improved rigidity for higher metal-removal rates, reduced vibration and improved tool life.

Several major casting enhancements coupled with the use of cross-roller guides enable customers to effectively use the additional 14 percent Y-stroke.

Higher Productivity

The nx machines are designed with a 1G-axis acceleration supplemented by high-power servo motors and enhanced casting rigidity for faster acceleration. To accommodate quicker acceleration/deceleration times, the nx machines add cooling to the ballscrew nut and linear guide packs.

Additionally, nx models have a standard direct-drive (DD) motor B-axis table for a dramatically faster indexing time over the previous worm-gear-driven NC rotary table (NCRT). The motor includes an inertia control system that adjusts table speed and acceleration based on pallet payload. Due to the speed of the DD motor, it may lead to fewer machines required in high-volume, high-tool-count automotive applications. The DD motor table also reduces B-axis complexity and eliminates backlash and key component wear.

Expanding Reliability

Makino’s a-Series machines have a well-established reputation for reliability as well as low maintenance, thanks to their long-lasting way covers, rigid spindle design and robust automatic tool changer (ATC). Nx machines leverage these proven designs and advance reliability with new features.

The ATC shutter door typically sees millions of cycles over the life span of a machine. On nx machines, a high-speed servo-driven ball screw actuates the ATC shutter door, improving responsiveness, ease of setup and maintenance. The servo axis also reduces exposure of the ATC to the work envelope. The net result is improved reliability and cleaner ATC environments.