Machine Highly Complex Geometries with Fewer Setups and Less Operations

Building on the high performance and reliability of their nx-series of four-axis HMCs, the versatile a500Z 5-axis horizontal machining center from Makino Inc. (Mason, OH) adds a fully integrated “Z-type” fifth axis to accommodate more complex part geometry challenges in a minimum number of workholding setups and machining operations. The unique kinematic arrangement of the a500Z minimizes the force path lengths both through the spindle as well as through the workpiece, efficiently transferring both cutting loads and reactive forces into the machine’s three point leveled bed, maximizing both metal removal rates and perishable tool life due to unparalleled system rigidity. This machine accommodates workpieces up to Ø24.8 in (Ø630 mm) x 19.9 in (500 mm) high, with payload weights up to 880 lb (400 kg). Its XY strokes are 28.7 in (730 mm) and 29.5 in (750 mm) respectively, with the Z-stroke ranging from 19.7 in to 27.6 in (500 mm to 700 mm), depending on the rotary axes positioning.

Both rotary tables are direct drive with unlimited 360 deg movement on the B-axis and 180 deg on the innovative ‘slant style’ C-axis unit for a full range of workpiece positioning, ranging from the pallet top sitting horizontal to the spindle centerline to parallel to the spindle centerline, or anywhere in between these two extremes. All axes have closed-loop active temperature control standard, providing not only superior dimensional control but also extended component life, even in the most demanding production environments. With rapid rates for all linear axes of 2,362 ipm (60 m/min) and a B-axis rotation rapid rate of 45,000 deg per minute, this agile platform allows for highly efficient machine movements. The standard 14,000 rpm high power spindle offers output capabilities of 49.6 hp (37 kW) peak power, and 223 ft-lb (303 Nm) peak torque, making it ideal for wide ranging material applications. An optional 20,000 rpm high speed spindle is offered for shops utilizing primarily small diameter tools in high speed machining applications.

Tool changer magazine sizes range from the standard 60-tool capacity ring type unit up to a 313-tool matrix type magazine. The standard automatic pallet changer greatly increases machine utilization, allowing workholding fixture tending on one pallet while the other pallet’s workpiece is being machined. Since the APC is fully integrated into the core of the machine tool, it offers both unparalleled operation ease and system reliability. The Fanuc-based Pro-6 CNC control is standard, featuring a user-friendly touch screen interface, advanced tool data management, and the patented Super Geometric Intelligence (SGI.5) high speed machining control system.

For highly efficient production of midsized cast iron and light alloy parts, the a71nx horizontal machining center has an expanded work envelope, improved ergonomics, increased spindle torque, innovative tool monitoring, advanced motion controls and the Professional 6 control. It features a 19.7 in (500 mm) pallet and added extensions in the XYZ axes, bringing their full-axis travels to 31.5 in, 29.5 in and 32.7 in (800 mm, 750 mm and 830 mm), respectively. These expanded axis travels increase the total machining volume by 16 percent to accommodate larger parts that weigh up to 1,000 kg. Because larger parts frequently require larger tools, the a71nx handles longer and heavier tools. Its standard 60-tool capacity automatic tool changer (ATC) has six reinforced pockets yielding a maximum tool length of 18.9 in/ 22.4 in (CAT/ HSK) and maximum weight of 30 kg. A direct-drive (DD) motor B-axis table delivers dramatically faster indexing time with one-second 90 deg rotation that substantially reduces non-cutting motion, reduces B-axis complexity and eliminates backlash and key component wear for improved reliability.

An updated high-power spindle takes spindle reliability and productivity to a new level. With options available for CAT-50, BT 50 and HSK-A100 interfaces, the standard 10,000 rpm spindle offers 37 kW of power (26 kW continuous power) and 512 Nm of torque (305 Nm continuous) for the flexibility and speed necessary to efficiently machine a variety of ferrous, hard metal or light alloy workpieces. The large-diameter angular contact bearings and direct-inject air-oil lubrication ensure the highest level of rigidity and longevity. An optional 20,000 rpm core-cooled spindle is also available. An innovative casting design and axis construction uses tiered, or stepped, column casting and oversized roller linear guides to boost rigidity, eliminate vibration and extend perishable tool life, even in the most challenging materials. Chip and coolant management is improved by a standard hydro-cyclonic filtration system that cleans coolant down to a 20 μm level, extending the maintenance life of the coolant.

One of the key advantages of the a71nx is its ability to reduce non-cut time from part processes with innovative, patent-pending hardware and control features. A vision-type broken-tool sensor (Vision B.T.S.) comes standard, supporting unattended operation by quickly validating the condition of cutting tools after each tool change. By creating a silhouette of the cutting tools, Vision B.T.S. is also able to evaluate the size and approximate weight of the tool. This information can then be applied to automatically set the tool-change speed to the appropriate setting (fast, medium or slow). This sensor system has fewer moving parts and requires no physical contact with the cutting tool for enhanced, long-term reliability and no risk of chipping delicate tool materials, such as polycrystalline diamond (PCD). The latest inertia active control (IAC) technologies enhance acceleration and deceleration rates in the B-axis, Z-axis and rotational positioning of the ring-type tool magazine. By quickly evaluating the total weight placed on these axes, IAC instantly adjusts acceleration to match the total load, reducing non-value-added times from part processes.

With the Professional 6 (Pro6) control, the a71nx is equipped with two advanced motion controls to minimize non-cut time:

• GI Drilling is a unique G-code drilling cycle that enables the spindle and tool to arc from hole to hole instead of following a square path. This simple change reduces non-cut time by as much as 15 percent on common hole-pattern drilling.
• GI Milling is designed to improve performance in 2D milling by letting the user define a corner-rounding tolerance on each milling path. Even a small tolerance enables the machine to quickly flow through the cut path, completing milling paths in less time.

Together, these functions substantially cut costs in both high volume and low volume production environments by reducing the number of spindles required and freeing up machine availability to take on more work. The exterior of this machine tool makes maintenance easier for the operator: Its L-shaped door, when open, allows more light to enter the machine and prevents fluid from dripping onto the operator during inspection and maintenance. The wide opening on the pallet-loading station doors lends easy access for loading of fixtures and large workpieces. This type of accessibility is crucial for part loading and unloading in robot-automated environments.

Makino Inc., 7680 Innovation Way, Mason, OH 45040, 513-573-7200, Fax: 513-573-7360, www.makino.com.