Large part production for industrial machinery, construction vehicles and heavy trucks, diesel engines, oil and gas machinery, and oversize dies and molds is no small job.
Some of these components can weigh up to 11,000 pounds, making a horizontal machining center of extraordinary capacity a must-have tool for efficient large part production machining. That’s why Makino has introduced the a120nx, one of its largest horizontal machining center platforms to date. Despite its size, the a120nx is also fast and accurate, while maintaining the legendary nx-series level of uptime and reliability.
Everything about the a120nx is sized for heavy-duty manufacturing:
- The work zone is Ø82.7 inches by 70.9 inches tall (Ø2,100 mm by 1,800 mm).
- The standard pallet size is 39.4 inches by 39.4 inches (1,000 mm by 1,000 mm),
with an option for 49.2 inches by 39.4 inches (1,250 mm by 1,000 mm).
- The standard automatic tool changer (ATC) magazine stores 204 tools, each of
which can be up to Ø14.0 inches (Ø356 mm) by 35.4 inches 900 mm) long,
and weigh up to 77 pounds (35 kg).
Supporting these outstanding payload capacities and providing a stable platform for repeatable precision machining is a three-point support of the bed casting. This design characteristic of the Makino nx-series machines simplifies installation, enables easy redeployment or relocation of the machine, and maintains the machine geometry and alignments.
“Big structural parts can pose big problems if you approach them the same way that you would other parts. With the a120nx, we wanted to take advantage of the many recent technological enhancements on our other nx-series machines,” said John Einberger, product line manager at Makino. “To ensure the a120nx is up to the unique challenges of machining the largest parts, we incorporated our core competencies, such as three-point leveling, multi-tiered column design, and precision pallet location and clamping system. These machining center design tenants, coupled with Makino’s renowned process know-how, work in concert to provide a fast, reliable solution for taking on parts of elephantine proportions.”
Building on the rigidity of the bed casting, the a120nx employs a unique tiered column design. There is a large step up in height from the front to rear X-axis linear guides that boosts machine rigidity high in the Y-axis by redirecting cutting forces back into the bed casting. This design provides a greater resistance to Z-axis cutting forces throughout the work envelope. Robust cross roller-style B-axis table bearings work in concert with a high force table clamping system to ensure stable cutting throughout the bigger work zone. Large parts frequently mean large features, too. Tool length, diameter and weight capacities of the a120nx support large face mills, boring bars and line-bar applications.
Feature-to-feature movements have the propensity to be much longer when machining large parts, requiring rapid traverse rates to be maximized in order to cover these increased distances quickly. To maintain ideal geometry and accuracy, the a120nx manages the heat generated by rapid traverse of 2,126 inches per minute using systems such as core-cooled ballscrews on all linear axes to ensure consistent accuracy during continuous production. Additionally, the ballscrews are all dual supported and pre-tensioned to ensure unparalleled dynamic positioning repeatability.
Powerful Spindle, Pallet Clamping for Speed and Accuracy
The nx-series spindle designs have improvements in productivity in cutting and non-cutting performance. The standard high torque 8,000-rpm spindle boosts continuous power levels by 19 percent over levels typical to machines of this class. With 50 continuous (74 peak) horsepower available, this spindle is ideally suited for heavy roughing of iron castings and hard-metal applications. In addition, the spindle features significant improvements in acceleration and deceleration due to its high duty rated performance characteristics that reduce rigid tapping times by up to 30 percent. Also available is an optional 18,000-rpm high power spindle, ideally suited to high metal removal rate machining of light alloy structural components.
The a120nx is equipped with Makino’s four cone pallet location and clamping system that delivers a secure 46,500 pounds of force on the pallet. This superior clamping capability, combined with all pallets built to a master pallet, eliminates deflection. An engineered precision air-blow system provides locating surfaces cleaning, as well as pallet clamp confirmation as standard features.
Additional chip and coolant management features include the nx-series center trough design being applied to this large capacity machining platform. The a120nx’s internally sloped surfaces remove obstructions between the workpiece and external chip conveyor, leading to efficient chip evacuation from the machining area. This innovative center trough design, combined with a simple, solid-panel Z-axis cover, reduces maintenance needs.
“This is an area that is frequently overlooked on many machine tools and results in interrupted operations, increased labor costs, machine damage, part-quality issues and reduced tool life. A properly designed chip and coolant management system like the ones on the a120nx can serve to boost manufacturing profitability,” Einberger said.
The a120nx comes to the market ‘automation ready’, being fully compatible with Makino’s versatile multi-machine, multi-pallet MMC-2 flexible manufacturing system, complete with Makino’s highly capable MAS-A5 cell controller.
Even when working with large parts, speed is a priority for businesses that must meet customers’ delivery demands. The automatic pallet changer (APC) switches from one pallet to the next in as little as 38 seconds. Tools are loaded into the automatic tool changer (ATC) from an exterior loading station without interrupting the machining process. Options for an ATC magazine side broken-tool sensor (BTSOMA), and automatic tool length measuring device, and an automatic workpiece measuring device are available.
|Pallet||39.4" (option 49.2" x 39.4")|
|Spindle RPM||8,000 (option 18,000)|
|Rapid Traverse||2,126 IPM|
|Cutting Feedrate||2,126 IPM|
|Maximum Workpiece||Ø82.7" x 70.9" high|
|Maximum Payload||6,600 lbs (option 11,000 lbs)|
|Tool to Tool||2.2 sec (12 kg) / 3.3 sec (35 kg)|
|Maximum Tool Length||35.4"|
|Maximum Tool Diameter||Ø14.0"|
|Maximum Tool Weight||77 lbs|
The a120nx 4-axis horizontal machining center expands the stroke and work-envelope size to accommodate structural components for heavy industrial, construction, vehicles, semi-conductor, oil and gas machinery.